@article{grice_varsbergs_zhang_zingales_johnson_sommer_karver_2024, title={Structural, computational, docking and biological studies of a triaminopyrimidine caspase-1 inhibitor}, volume={1318}, ISSN={["1872-8014"]}, DOI={10.1016/j.molstruc.2024.139297}, journal={JOURNAL OF MOLECULAR STRUCTURE}, author={Grice, Kyle A. and Varsbergs, Zoe M. and Zhang, Yingjie and Zingales, Sarah K. and Johnson, Adam R. and Sommer, Roger D. and Karver, Caitlin E.}, year={2024}, month={Dec} } @article{grice_crespo_anselmo_bobrov_farooqui_lawando_sommer_2023, title={Synthesis, characterization, computational studies, and reactivity of platinum(II) complexes of alkyl phosphite ligands}, volume={999}, ISSN={["1872-8561"]}, DOI={10.1016/j.jorganchem.2023.122817}, abstractNote={Air-stable phosphite-ligated platinum complexes of the form cis-Pt(P(OR)3)2Cl2 and cis-Pt(P(OR)3)2Me2 based on five small alkyl phosphite ligands have been synthesized and characterized. The crystal structures for several of these species are reported, allowing for comparison between spectroscopic and structural parameters. Michaelis-Arbuzov-type dealkylation during synthesis was observed for some of the phosphite ligands, and a dealkylated product was structurally characterized. Density Functional Theory (DFT) and Quantum Theory of Atoms in Molecules (QTAIM) was also used to examine the electronic structure of the phosphite compounds. The QTAIM results support the increased π-acidity of the phosphite ligands compared to analogous phosphines. Thermolysis experiments were performed to examine the stability and reactivity of Pt(P(OR)3)2X2 species. It was found that coordinated P(OiPr)3 ligands decompose via cyclometallation and propylene extrusion.}, journal={JOURNAL OF ORGANOMETALLIC CHEMISTRY}, author={Grice, Kyle A. and Crespo, Edgar J. and Anselmo, Mirachelle M. and Bobrov, Sean F. and Farooqui, Farah T. and Lawando, Anthony E. and Sommer, Roger D.}, year={2023}, month={Oct} } @article{han_sommer_boyle_zhou_young_borodin_henderson_2022, title={Electrolyte Solvation and Ionic Association: Part IX. Structures and Raman Spectroscopic Characterization of LiFSI Solvates}, volume={169}, ISSN={["1945-7111"]}, url={https://doi.org/10.1149/1945-7111/ac9a07}, DOI={10.1149/1945-7111/ac9a07}, abstractNote={The bis(fluorosulfonyl)imide anion N(SO2F)2 − (i.e., FSI−) (also referred to as bis(fluorosulfonyl)amide (i.e., FSA−) and imidodi(sulphuryl fluoride)) has attracted tremendous interest in recent years for its utility in both lithium salts and ionic liquids for battery electrolyte applications. To facilitate the understanding of the characteristics of this anion, crystal structures are reported here for the uncoordinated anion in LiFSI-based solvates with cryptand CRYPT-222 and tetraglyme (G4). These crystalline solvates were analyzed by Raman spectroscopy to aid in assigning the Raman bands to the modes of ion coordination found in liquid electrolytes. These structures, as well as a thorough review of other relevant crystallographic data, provide insights into the rather remarkable properties of the FSI− anion with regard to solvate formation and electrolyte properties.}, number={11}, journal={JOURNAL OF THE ELECTROCHEMICAL SOCIETY}, author={Han, Sang-Don and Sommer, Roger D. and Boyle, Paul D. and Zhou, Zhi-Bin and Young, Victor G. and Borodin, Oleg and Henderson, Wesley A.}, year={2022}, month={Nov} } @article{yun_han_borodin_seo_afroz_sommer_henderson_2022, title={Solvate Structures and Computational/Spectroscopic Characterization of LiCF3SO3 Electrolytes}, volume={126}, ISSN={["1932-7455"]}, DOI={10.1021/acs.jpcc.2c06170}, abstractNote={An extensive correlation study has been conducted utilizing known LiCF3SO3 solvate crystal structures having specific modes of CF3SO3–···Li+ ion coordination and the corresponding anion Raman vibrational band positions to delineate the assignments of specific vibrational bands to these ion coordination modes. To facilitate this study, three new crystalline solvate structures─(12C4)2:LiCF3SO3, (BN)1:LiCF3SO3, and (MA)1:LiCF3SO3 with 12-crown-4 (12C4), butyronitrile (BN) and methyl acetate (MA)─have been determined. The trifluoromethanesulfonate or "triflate" anion is an excellent probe for exploring electrolyte interactions since two separate Raman bands may be used for the evaluation and the anion exhibits a wide range of coordination modes in electrolytes with varying solvents.}, number={43}, journal={JOURNAL OF PHYSICAL CHEMISTRY C}, author={Yun, Sung-Hyun and Han, Sang-Don and Borodin, Oleg and Seo, Daniel M. and Afroz, Taliman and Sommer, Roger D. and Henderson, Wesley A.}, year={2022}, month={Nov}, pages={18251–18265} } @article{fick_liu_nussbaumer_kreutz_rangadurai_xu_sommer_shi_scheiner_stelling_2021, title={Probing the Hydrogen-Bonding Environment of Individual Bases in DNA Duplexes with Isotope-Edited Infrared Spectroscopy}, volume={125}, ISSN={["1520-5207"]}, url={https://doi.org/10.1021/acs.jpcb.1c01351}, DOI={10.1021/acs.jpcb.1c01351}, abstractNote={Measuring the strength of the hydrogen bonds between DNA base pairs is of vital importance for understanding how our genetic code is physically accessed and recognized in cells, particularly during replication and transcription. Therefore, it is important to develop probes for these key hydrogen bonds (H-bonds) that dictate events critical to cellular function, such as the localized melting of DNA. The vibrations of carbonyl bonds are well-known probes of their H-bonding environment, and their signals can be observed with infrared (IR) spectroscopy. Yet, pinpointing a single bond of interest in the complex IR spectrum of DNA is challenging due to the large number of carbonyl signals that overlap with each other. Here, we develop a method using isotope editing and infrared (IR) spectroscopy to isolate IR signals from the thymine (T) C2=O carbonyl. We use solvatochromatic studies to show that the TC2=O signal’s position in the IR spectrum is sensitive to the H-bonding capacity of the solvent. Our results indicate that C2=O of a single T base within DNA duplexes experiences weak H-bonding interactions. This finding is consistent with the existence of a third, noncanonical CH···O H-bond between adenine and thymine in both Watson–Crick and Hoogsteen base pairs in DNA.}, number={28}, journal={JOURNAL OF PHYSICAL CHEMISTRY B}, publisher={American Chemical Society (ACS)}, author={Fick, Robert J. and Liu, Amy Y. and Nussbaumer, Felix and Kreutz, Christoph and Rangadurai, Atul and Xu, Yu and Sommer, Roger D. and Shi, Honglue and Scheiner, Steve and Stelling, Allison L.}, year={2021}, month={Jul}, pages={7613–7627} } @article{nguyen_wang_sommer_lindsey_2020, title={Asymmetric Synthesis of a Bacteriochlorophyll Model Compound Containing trans-Dialkyl Substituents in Ring D}, volume={85}, url={https://doi.org/10.1021/acs.joc.0c00608}, DOI={10.1021/acs.joc.0c00608}, abstractNote={Challenges to the de novo synthesis of bacteriochlorophyll a (BChl a), the chief pigment for anoxygenic bacterial photosynthesis, include creating the macrocycle along with the trans-dialkyl substituents in both pyrroline rings (B and D). A known route to a model bacteriochlorophyll with a gem-dimethyl group in each pyrroline ring has been probed for utility in the synthesis of BChl a by preparation of a hybrid macrocycle (BC-1), which contains a trans-dialkyl group in ring D and a gem-dimethyl group in ring B. Stereochemical definition began with the synthesis of (2S,3S)-2-ethyl-3-methylpent-4-ynoic acid, a precursor to the trans-dialkyl-substituted AD dihydrodipyrrin. Knoevenagel condensation of the latter and a gem-dimethyl, β-ketoester-substituted BC dihydrodipyrrin afforded the enone (E, 70%; Z, 3%); subsequent double-ring cyclization of the E-enone (via Nazarov, electrophilic aromatic substitution, and elimination reactions) gave BC-1 (53% yield) along with a trace of chlorin byproduct (1.4% relative to BC-1 upon fluorescence assay). BC-1 exhibited the desired trans-dialkyl stereochemistry in ring D and was obtained as a 7:1 mixture of (expected) epimers owing to the configuration of the 132-carbomethoxy substituent. The strategy wherein trans-dialkyl substituents are installed very early and carried through to completion, as validated herein, potentially opens a synthetic path to native photosynthetic pigments.}, number={10}, journal={The Journal of Organic Chemistry}, publisher={American Chemical Society (ACS)}, author={Nguyen, Khiem Chau and Wang, Pengzhi and Sommer, Roger D. and Lindsey, Jonathan S.}, year={2020}, month={May}, pages={6605–6619} } @article{donal f. o'shea_sommer_taniguchi_lindsey_2020, title={Crystal Structure of 1,9-Dibromo-5-phenyldipyrrin, Tetrapyrrole Synthesis Derivative and Free Base Ligand of BODIPY Building Blocks}, volume={36}, ISSN={["1883-3578"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85089361305&partnerID=MN8TOARS}, DOI={10.2116/xraystruct.36.21}, abstractNote={A free base ligand of a BODIPY building block, 1,9-dibromo-5-phenyldipyrrin (2), was synthesized. The crystal structure was determined by the single crustal X-ray diffraction method at 293 K. The compound crystallizes in a monoclinic system and was characterized as follows: P21/c, a = 9.94150(10), b = 15.8691(3), c = 10.2160(2)Å, β = 118.8050(6), Z = 4, V = 1412.28(4)Å3, Dcalcd = 1.778 g/cm3, Z = 4. The R1 [I > 2σ(I)] and wR2 (all data) values are 0.0266 and 0.0653, respectively, for all 2896 independent reflections.}, journal={X-RAY STRUCTURE ANALYSIS ONLINE}, author={Donal F. O'shea and Sommer, Roger D. and Taniguchi, Masahiko and Lindsey, Jonathan S.}, year={2020}, month={Jul}, pages={21–22} } @article{guzmán santiago_brown_sommer_ison_2020, title={Identification of key functionalization species in the Cp*Ir(iii)-catalyzed-ortho halogenation of benzamides}, volume={49}, ISSN={1477-9226 1477-9234}, url={http://dx.doi.org/10.1039/D0DT00565G}, DOI={10.1039/D0DT00565G}, abstractNote={Cp*Ir(iii) complexes have been shown to be effective for the halogenation of N,N-diisopropylbenzamides with N-halosuccinimide as a suitable halogen source.}, number={45}, journal={Dalton Transactions}, publisher={Royal Society of Chemistry (RSC)}, author={Guzmán Santiago, Alexis J. and Brown, Caleb A. and Sommer, Roger D. and Ison, Elon A.}, year={2020}, pages={16166–16174} } @article{shultz_kirk_zhang_stasiw_wang_yang_habel-rodriguez_stein_sommer_2020, title={Spectroscopic Signatures of Resonance Inhibition Reveal Differences in Donor–Bridge and Bridge–Acceptor Couplings}, volume={142}, url={https://doi.org/10.1021/jacs.0c00326}, DOI={10.1021/jacs.0c00326}, abstractNote={The torsional dependence of the ground state magnetic exchange coupling (J), and the corresponding electronic coupling matrix element (HDA) for eight transition metal complexes possessing donor-acceptor (D-A) biradical ligands is presented. These biradical ligands are comprised of an S= ½ metal semiquinone (SQ) donor and an S = ½ nitronylnitroxide (NN) acceptor, which are coupled to each other via para-phenylene, methyl-substituted para-phenylenes, or bicyclo[2.2.2]octane ring. The observed trends in electronic absorption- and resonance Raman spectral features are in accord with reduction in electronic and magnetic coupling between D and A units within the framework of our valence bond configuration interaction model. Moreover, our spectroscopic results highlight different orbital mechanisms that modulate coupling in these complexes, that is not manifest in the ferromagnetic JSQ-B-NN values. The work provides new detailed insight into the effects of torsional rotations which contribute to inhomogeneities in experimentally determined exchange couplings, electron transfer rates, and electron transport conductance measurements.}, number={10}, journal={Journal of the American Chemical Society}, publisher={American Chemical Society (ACS)}, author={Shultz, David A. and Kirk, Martin L. and Zhang, Jinyuan and Stasiw, Daniel E. and Wang, Guangbin and Yang, Jing and Habel-Rodriguez, Diana and Stein, Benjamin W. and Sommer, Roger D.}, year={2020}, month={Mar}, pages={4916–4924} } @article{lambić_sommer_ison_2020, title={Synthesis and reactivity of nitridorhenium complexes incorporating the mercaptoethylsulfide (SSS) ligand}, volume={49}, url={https://doi.org/10.1039/D0DT00631A}, DOI={10.1039/D0DT00631A}, abstractNote={The steric profile of the SSS ligand combined with enhanced nucleophilicity of the nitrido group is important for FLP reactivity.}, journal={Dalton Transactions}, publisher={Royal Society of Chemistry (RSC)}, author={Lambić, N.S. and Sommer, R.D. and Ison, E.A.}, year={2020}, pages={6127–6134} } @article{short_sommer_falzone_huang_weare_roizen_2019, title={A five-coordinate iron(III) porphyrin complex including a neutral axial pyridine N-oxide ligand}, volume={75}, url={https://doi.org/10.1107/S2053229619005849}, DOI={10.1107/S2053229619005849}, abstractNote={While six-coordinate iron(III) porphyrin complexes with pyridine N-oxides as axial ligands have been studied as they exhibit rare spin-crossover behavior, studies of five-coordinate iron(III) porphyrin complexes including neutral axial ligands are rare. A five-coordinate pyridine N-oxide–5,10,15,20-tetraphenylporphyrinate–iron(III) complex, namely (pyridine N-oxide-κO)(5,10,15,20-tetraphenylporphinato-κ4 N,N′,N′′,N′′′)iron(III) hexafluoroantimonate(V) dichloromethane disolvate, [Fe(C44H28N4)(C5H5NO)][SbF6]·2CH2Cl2, was isolated and its crystal structure determined in the space group P\overline{1}. The porphyrin core is moderately saddled and the Fe—O—N bond angle is 122.08 (13)°. The average Fe—N bond length is 2.03 Å and the Fe—ONC5H5 bond length is 1.9500 (14) Å. This complex provides a rare example of a five-coordinate iron(III) porphyrin complex that is coordinated to a neutral organic ligand through an O-monodentate binding mode.}, number={6}, journal={Acta Crystallographica Section C Structural Chemistry}, publisher={International Union of Crystallography (IUCr)}, author={Short, Melanie A. and Sommer, Roger D. and Falzone, Alec J. and Huang, Tao and Weare, Walter W. and Roizen, Jennifer L.}, year={2019}, month={Jun}, pages={717–722} } @article{brown_lilly_lambic_sommer_ison_2020, title={Synthesis and Reactivity of Re(III) and Re(V) Fischer Carbenes}, volume={39}, ISSN={["1520-6041"]}, DOI={10.1021/acs.organomet.9b00600}, abstractNote={Direct insertion of CO and isocyanides, RNC, into Re–R bonds results in high-oxidation-state acyl and iminoacyl complexes that can be treated with an electrophile to generate rare examples of rheni...}, number={3}, journal={ORGANOMETALLICS}, author={Brown, Caleb A. and Lilly, Cassandra P. and Lambic, Nikola S. and Sommer, Roger D. and Ison, Elon A.}, year={2020}, month={Feb}, pages={388–396} } @article{garcia_pech_sommer_gorman_2019, title={Synthesis of 5,12-Diazapentacenes and Their Properties}, volume={84}, ISSN={["1520-6904"]}, url={https://doi.org/10.1021/acs.joc.9b01628}, DOI={10.1021/acs.joc.9b01628}, abstractNote={An efficient synthesis via a precursor route to a new class of linear dialkyldiaminoazapentacenes is reported. The synthetic route involves the coupling of 4 substituted aniline derivatives to 2,5 dibromoterephthalonitrile via Buchwald Hartwig amination followed by an acid mediated cyclization to furnish the diazapentacenes. These reactions occur under short reaction times (<2 h.) and high yields (77-99%) and do not require column chromatography for purification. The electrochemical and optical properties of the diazapentacenes were evaluated, and the values indicate that these molecules are promising n-type materials for organic electronic devices. The photostability of these molecules was significantly greater than unsubstituted acenes. Their method of degradation via endoperoxide generation was confirmed by X-ray crystallography and mass spectrometry.}, number={23}, journal={JOURNAL OF ORGANIC CHEMISTRY}, publisher={American Chemical Society (ACS)}, author={Garcia, Rosalva C. and Pech, Matthew J. and Sommer, Roger and Gorman, Christopher B.}, year={2019}, month={Dec}, pages={15079–15086} } @article{chakraborty_yarnell_sommer_roy_castellano_2018, title={Excited-State Processes of Cyclometalated Platinum(II) Charge-Transfer Dimers Bridged by Hydroxypyridines}, volume={57}, ISSN={0020-1669 1520-510X}, url={http://dx.doi.org/10.1021/acs.inorgchem.7b02736}, DOI={10.1021/acs.inorgchem.7b02736}, abstractNote={A series of four anti-disposed dinuclear platinum(II) complexes featuring metal-metal-to-ligand charge-transfer (MMLCT) excited states, bridged by either 2-hydroxy-6-methylpyridine or 2-hydroxy-6-phenylpyridine and cyclometalated with 7,8-benzoquinoline or 2-phenylpyridine, are presented. The 2-hydroxypyridine bridging ligands control intramolecular d8-d8 metal-metal σ interactions, affecting the frontier orbitals' electronic structure, resulting in marked changes to the ground- and excited-state properties of these complexes. Three of these molecules possess reversible one-electron oxidations in cyclic voltammetry experiments as a result of strong intramolecular metallophilic interactions. In this series of molecules, X-ray crystallography revealed Pt-Pt distances ranging between 2.815 and 2.878 Å; the former represents the shortest reported metal-metal distance for platinum(II) dimers possessing low-energy MMLCT transitions. All four molecules reported here display visible absorption bands beyond 500 nm and feature MMLCT-based red photoluminescence (PL) above 700 nm at room temperature with high PL quantum yields (up to 4%) and long excited-state lifetimes (up to 341 ns). The latter were recorded using both transient PL and transient absorption experiments that self-consistently yielded quantitatively identical excited-state lifetimes. The energy-gap law was successfully applied to this series of chromophores, documenting this behavior for the first time in molecules possessing MMLCT excited states. The combined data illustrate that entirely new classes of MMLCT chromophores can be envisioned using bridging pyridyl hydroxides in cooperation with various C^N cyclometalates to achieve photophysical properties suitable for excited-state electron- and energy-transfer chemistry.}, number={3}, journal={Inorganic Chemistry}, publisher={American Chemical Society (ACS)}, author={Chakraborty, Arnab and Yarnell, James E. and Sommer, Roger D. and Roy, Subhangi and Castellano, Felix N.}, year={2018}, month={Jan}, pages={1298–1310} } @article{hou_powel_dougherty_sommer_maggard_2018, title={Tunable Optical and Photocatalytic Properties of Low-Dimensional Copper(I)-Iodide Hybrids Using Coordinating Organic Ligands}, volume={18}, ISSN={["1528-7505"]}, DOI={10.1021/acs.cgd.8b00788}, abstractNote={A family of copper(I)-iodide/organic hybrid compounds was investigated for the impact of coordinating organic ligands on their structures, as well as on their optical and photocatalytic properties. This included the synthesis of two new crystalline compounds, [(CuI)2(bpmd)] and [(CuI)2(bpp)] (bpmd = 2,2′-bipyrimidine, bpp = 2,3-bis(2-pyridyl)pyrazine), both of which consist of chain structures formed by (CuI)2 rhombus-shaped dimers that are further coordinated to the N-groups of the bridging organic ligands. To more broadly investigate structure–property relationships within this system, nine related copper(I)-iodide/organic hybrid compounds, that is, [(CuI)2Ln] (n = 1 or 2; L = 1,2-bis(4-pyridyl) ethylene (bpe); 2,2′-bipyrimidine (bpmd); 2,3-bis(2-pyridyl) pyrazine (bpp); 4,4′-bipyridine (44bpy); pyridazine (pdz); pyrimidine (pmd); pyrazine (pz); pyrazinamide (pza); quinoxaline (quin)) were also prepared in high purity containing extended (CuI)∞ chains or sheets coordinated to bridging or terminating org...}, number={9}, journal={CRYSTAL GROWTH & DESIGN}, author={Hou, Feier and Powel, Matthew and Dougherty, Daniel B. and Sommer, Roger D. and Maggard, Paul A.}, year={2018}, month={Sep}, pages={5406–5416} } @article{perez_smeltz_sommer_boyle_ison_2017, title={Cationic rhenium ((III)) complexes: synthesis, characterization, and reactivity for hydrosilylation of aldehydes}, volume={46}, DOI={10.1039/c7dt00271h}, abstractNote={Cationic Re(iii) complexes are shown to be more active for the catalytic hydrosilylation of benzaldehydes than their neutral acetate precursors.}, number={14}, journal={Dalton Transactions (Cambridge, England : 2003)}, author={Perez, D. E. and Smeltz, J. L. and Sommer, Roger D. and Boyle, P. D. and Ison, E. A.}, year={2017}, pages={4609–4616} } @article{lambic_brown_sommer_ison_2017, title={Dramatic Increase in the Rate of Olefin Insertion by Coordination of Lewis Acids to the Oxo Ligand in Oxorhenium(V) Hydrides}, volume={36}, ISSN={["1520-6041"]}, DOI={10.1021/acs.organomet.7b00291}, abstractNote={In this work we show that classic coordination of the oxo group in an oxorhenium hydride complex to M(C6F5)3 (M = Al, B) leads to dramatic increases in the rate of migratory olefin insertion. Combined experimental and computational studies have been utilized to understand the reasons for the rate enhancement upon coordination of the oxo group to the Lewis acid. The mechanism for migratory insertion involves coordination of the olefin to rhenium in the equatorial plane. This induces mixing of the rhenium–hydride σ bond with a rhenium–oxygen π* orbital. This results in an accumulation of electron density on the oxo ligand. The Lewis acid lowers the barrier for migratory insertion by diminishing the electron density on the oxo ligand in the transition state.}, number={10}, journal={ORGANOMETALLICS}, publisher={American Chemical Society (ACS)}, author={Lambic, Nikola S. and Brown, Caleb A. and Sommer, Roger D. and Ison, Elon A.}, year={2017}, month={May}, pages={2042–2051} } @article{kirk_shultz_zhang_dangi_ingersol_yang_finney_sommer_wojtas_2017, title={Heterospin biradicals provide insight into molecular conductance and rectification}, volume={8}, ISSN={2041-6520 2041-6539}, url={http://dx.doi.org/10.1039/C7SC00073A}, DOI={10.1039/c7sc00073a}, abstractNote={Properties of two isomeric triplet ground state biradical molecules, which serve as constant-bias analogs of single-molecule electronic devices, are described and experimental results are compared with transport calculations in a device geometry.}, number={8}, journal={Chemical Science}, publisher={Royal Society of Chemistry (RSC)}, author={Kirk, Martin L. and Shultz, David A. and Zhang, Jinyuan and Dangi, Ranjana and Ingersol, Laura and Yang, Jing and Finney, Nathaniel S. and Sommer, Roger D. and Wojtas, Lukasz}, year={2017}, pages={5408–5415} } @article{lambic_sommer_ison_2018, title={High-valent nitridorhenium(V) complexes containing PNP ligands: implications of ligand flexibility}, volume={47}, ISSN={["1477-9234"]}, url={https://doi.org/10.1039/C7DT03615A}, DOI={10.1039/c7dt03615a}, abstractNote={The synthesis of (PNP)Re(N)X (PNP = [2-P(CHMe2)2-4-MeC6H3]2N, X = Cl and Me) complexes is described.}, number={3}, journal={DALTON TRANSACTIONS}, publisher={Royal Society of Chemistry (RSC)}, author={Lambic, Nikola S. and Sommer, Roger D. and Ison, Elon A.}, year={2018}, month={Jan}, pages={758–768} } @article{patil_ghosh_cao_sommer_grice_waris_patil_2017, title={Novel 5-arylthio-5H-chromenopyridines as a new class of anti-fibrotic agents}, volume={27}, ISSN={["1464-3405"]}, DOI={10.1016/j.bmcl.2017.01.089}, abstractNote={Liver fibrosis is a critical wound healing response to chronic liver injury such as hepatitis C virus (HCV) infection. If persistent, liver fibrosis can lead to cirrhosis and hepatocellular carcinoma (HCC). The development of new therapies for preventing liver fibrosis and its progression to cancer associated with HCV infection remains a critical challenge. Identification of novel anti-fibrotic compounds will provide opportunities for innovative therapeutic intervention of HCV-mediated liver fibrosis. We designed and synthesized a focused set of 5-arylthio-5H-chromenopyridines as a new class of anti-fibrotic agents. Liver fibrosis assays demonstrated that the compounds 3a and 3c show inhibitory activity towards human hepatic stellate cells (LX2) activation at 10μM. The HCV NS3 and NS5A proteins in HCV subgenome-expressing cells were also significantly reduced in cells treated with 3a and 3c, suggesting the possible inhibitory role of the compounds in HCV translation/replication activities. We have also examined the reactivity of these compounds with medicinally-relevant metal compounds such as platinum and gold. The reactivity of these complexes with metals and during Mass Spectrometry suggests that CS bond cleavage is relatively facile.}, number={5}, journal={BIOORGANIC & MEDICINAL CHEMISTRY LETTERS}, publisher={Elsevier BV}, author={Patil, Renukadevi and Ghosh, Anandita and Cao, Phoebus Sun and Sommer, Roger D. and Grice, Kyle A. and Waris, Gulam and Patil, Shivaputra}, year={2017}, month={Mar}, pages={1129–1135} } @article{grice_patil_ghosh_paner_guerrero_camacho_cao_niyazi_zainab_sommer_et al._2018, title={Understanding the structure and reactivity of the C-S linkage in biologically active 5-arylthio-5H-chromenopyridines}, volume={42}, ISSN={["1369-9261"]}, url={https://doi.org/10.1039/C7NJ03724D}, DOI={10.1039/c7nj03724d}, abstractNote={Biologically-active 5-arylthio-5H-chromenopyridines were examined to understand their chemical properties.}, number={2}, journal={NEW JOURNAL OF CHEMISTRY}, publisher={Royal Society of Chemistry (RSC)}, author={Grice, Kyle A. and Patil, Renukadevi and Ghosh, Anandita and Paner, Jesse D. and Guerrero, Michael A. and Camacho, Ehxciquiel Jaeroume M. and Cao, Phoebus Sun and Niyazi, Aeshah H. and Zainab, Sitwat and Sommer, Roger D. and et al.}, year={2018}, month={Jan}, pages={1151–1158} } @article{huggins_minrovic_corey_jacobs_melander_sommer_zurawski_melander_2017, title={1,2,4-Triazolidine-3-thiones as Narrow Spectrum Antibiotics against Multidrug-Resistant Acinetobacter baumannii}, volume={8}, ISSN={["1948-5875"]}, DOI={10.1021/acsmedchemlett.6b00296}, abstractNote={With only two new classes of antibiotics developed in the last 40 years, novel antibiotics are desperately needed to combat the growing problem of multidrug-resistant and extensively drug resistant bacteria, particularly Gram-negative bacteria. Described in this letter is the synthesis and antibiotic activity of 1,2,4-triazolidine-3-thiones as narrow spectrum antibiotics. Optimization of the 1,2,4-triazolidine-3-thione scaffold identified a small molecule with potent antibiotic activity against multiple strains of multidrug-resistant and extensively drug-resistant Acinetobacter baumannii. This small molecule also shows single dose, in vivo activity in a Galleria mellonella infection model with A. baumannii and represents a promising start in the development of a class of drugs that can target this bacterial pathogen.}, number={1}, journal={ACS MEDICINAL CHEMISTRY LETTERS}, publisher={American Chemical Society (ACS)}, author={Huggins, William M. and Minrovic, Bradley M. and Corey, Brendan W. and Jacobs, Anna C. and Melander, Roberta J. and Sommer, Roger D. and Zurawski, Daniel V. and Melander, Christian}, year={2017}, month={Jan}, pages={27–31} } @article{goggins_lekich_weare_sommer_ribeiro_pinheiro_2016, title={A Periodic Walk through a Series of First-Row, Oxido-Bridged, Heterodimetallic Molecules: Synthesis and Structure}, volume={2016}, ISSN={["1099-0682"]}, DOI={10.1002/ejic.201501325}, abstractNote={AbstractA series of heterodimetallic molecules, centered around an LTi=O→M2+L′ (M = Mn, Fe, Co, Ni, Cu, Zn) core, are described. Each of these complexes are structurally similar, with L = tmtaa and L′ = Py5Me2. The Ti=O→M linkage is slightly bent, varying from 157° (Mn) to 170° (Zn), with bond lengths typical of a dative bond between the Ti=O group and the M2+ center. The relative strength of the heterodimetallic linkage is correlated with the Lewis acidity of the M2+ precursor, with Mn2+ showing the strongest interaction and Ni2+ the weakest. By varying the metal identity the electrochemical properties of the molecules can be tuned, along with the M3+/2+ redox couple. This series of complexes provide a platform for studying structure/function relationships in heterodimetallic molecules linked through a single atom. For instance, spectroscopic features such as IR stretching frequencies can be roughly correlated with structural features such as bond lengths and angles.}, number={7}, journal={EUROPEAN JOURNAL OF INORGANIC CHEMISTRY}, publisher={Wiley}, author={Goggins, Eric M. and Lekich, Travis T. and Weare, Walter W. and Sommer, Roger D. and Ribeiro, Marcos A. and Pinheiro, Carlos B.}, year={2016}, month={Mar}, pages={1054–1059} } @article{allen_lathrop_patel_moody_sommer_coombs_2016, title={ChemInform Abstract: Synthesis of 7-Norbornenols via Diels-Alder Cycloadditions of Cyclopentadienol Generated by Decomposition of Ferrocenium Cation.}, volume={47}, DOI={10.1002/chin.201609095}, abstractNote={AbstractIn situ generated cyclopentadienol is trapped via Diels—Alder reaction with various dienophiles to produce single diastereomers of norborneol derivatives.}, number={9}, journal={ChemInform}, publisher={Wiley}, author={Allen, Stacey K. and Lathrop, Thomas E. and Patel, Sweta B. and Moody, Deanna M. Harrell and Sommer, Roger D. and Coombs, Thomas C.}, year={2016}, month={Feb}, pages={no-no} } @article{robbins_lilly_sommer_ison_2016, title={Effect of the Ancillary Ligand on the Mechanism for CO Migratory Insertion in High-Valent Oxorhenium Complexes}, volume={35}, ISSN={["1520-6041"]}, DOI={10.1021/acs.organomet.6b00570}, abstractNote={Several oxorhenium complexes bearing an SSS pincer ligand were isolated and characterized, and their reactivity with carbon monoxide was explored. The corresponding oxorhenium(V) acyl derivatives were also isolated and characterized. Carbonylation reactions required high pressures (400 psi) and temperatures (50 °C). The mechanism for carbonylation was explored with DFT (M06) calculations and revealed that the most likely mechanism for carbonylation involved stepwise formation of CO adducts followed by migration of the carbonyl ligand to the alkyl/aryl groups.}, number={20}, journal={ORGANOMETALLICS}, publisher={American Chemical Society (ACS)}, author={Robbins, Leanna K. and Lilly, Cassandra P. and Sommer, Roger D. and Ison, Elon A.}, year={2016}, month={Oct}, pages={3530–3537} } @article{lambic_lilly_sommer_ison_2016, title={Mechanism for the Reaction of CO with Oxorhenium Hydrides: Migratory Insertion of CO into Rhenium Hydride and Formyl Bonds leads to Migration from Rhenium to the Oxo Ligand}, volume={35}, ISSN={["1520-6041"]}, DOI={10.1021/acs.organomet.6b00591}, abstractNote={Computational studies (M06) have been performed in synergy with experimental studies to show that the thermodynamics for insertion of CO into an oxorhenium–hydride bond to form a formyl ligand is favorable despite conventional wisdom to the contrary. Further, it is shown that insertion of CO into formyl ligands to form α-dicarbonyl ligands is also a viable pathway and results in hydroxy carbonyl or formate complexes, depending on the nature of the ancillary ligand.}, number={17}, journal={ORGANOMETALLICS}, publisher={American Chemical Society (ACS)}, author={Lambic, Nikola S. and Lilly, Cassandra P. and Sommer, Roger D. and Ison, Elon A.}, year={2016}, month={Sep}, pages={3060–3068} } @article{frasco_mukherjee_sommer_perry_lambic_abboud_jakubikoya_ison_2016, title={Nondirected C-H Activation of Arenes with Cp*Ir(III) Acetate Complexes: An Experimental and Computational Study}, volume={35}, ISSN={["1520-6041"]}, DOI={10.1021/acs.organomet.6b00308}, abstractNote={Combined experimental and computational studies have revealed factors that influence the nondirected C–H activation in Cp*Ir complexes that contain carboxylate ligands. A two-step acetate-assisted pathway was shown to be operational where the first step involves substrate binding and the second step involves cleavage of the C–H bond of the substrate. A nonlinear Hammett plot was obtained to examine substituted arenes where a strong electronic dependence (ρ = 1.67) was observed for electron-donating groups, whereas no electronic dependence was observed for electron-withdrawing groups. Electron-donating substituents in the para position were shown to have a bigger impact on the C–H bond cleavage step, whereas electron-withdrawing substituents influenced the substrate-binding step. Although cleavage of the C–H bond was predicted to be more facile with arenes that contain substituents in the para position by DFT calculations, the cyclometalations of anisole and benzonitrile were observed experimentally. This ...}, number={15}, journal={ORGANOMETALLICS}, publisher={American Chemical Society (ACS)}, author={Frasco, Daniel A. and Mukherjee, Sriparna and Sommer, Roger D. and Perry, Cody M. and Lambic, Nikola S. and Abboud, Khalil A. and Jakubikoya, Elena and Ison, Elon A.}, year={2016}, month={Aug}, pages={2435–2445} } @article{lambic_lilly_robbins_sommer_ison_2016, title={Reductive Carbonylation of Oxorhenium Hydrides Induced by Lewis Acids}, volume={35}, ISSN={["1520-6041"]}, DOI={10.1021/acs.organomet.6b00393}, abstractNote={Several oxorhenium hydride complexes with chelating diamidopyridine (DAP), diamidoamine (DAAm), and 2-mercaptoethyl sulfide (SSS) groups have been isolated and characterized. Adduct formation is observed when the DAP complex 1a is treated with the Lewis acid B(C6F5)3. However, treatment of 1a,b with B(C6F5)3 or BF3·OEt2 in the presence of CO results in reduction of the metal center by four electrons from Re(V) to Re(I).}, number={17}, journal={ORGANOMETALLICS}, publisher={American Chemical Society (ACS)}, author={Lambic, Nikola S. and Lilly, Cassandra P. and Robbins, Leanna K. and Sommer, Roger D. and Ison, Elon A.}, year={2016}, month={Sep}, pages={2822–2829} } @article{cao_sommer_grice_2016, title={Structural comparison of suberanilohydroxamic acid (SAHA) and other zinc-enzyme inhibitors bound to a monomeric zinc species}, volume={114}, ISSN={["0277-5387"]}, DOI={10.1016/j.poly.2016.01.029}, abstractNote={Histone Deacetylase (HDAC) and similar proteins contain an active Zn–OH group and have been targets for inhibitors. Known inhibitors such as suberanilohydroxamic acid (SAHA), suberohydroxamic acid (SBHA), valproic acid, and 8-hydroxyquinoline (8-HQ) derivatives act on these enzymes by binding to the zinc center. To examine how these drugs interacted with zinc centers and to examine their structural differences, a homogeneous zinc complex was synthesized and reacted with SAHA, SBHA, valproic acid, and 8-HQ to form stable adducts, which were characterized by spectroscopy and X-ray crystallography. A comparison of their structures with known complexes and enzyme active sites bound to drugs was performed in order to understand how these drugs interact with their targets.}, journal={POLYHEDRON}, publisher={Elsevier BV}, author={Cao, Phoebus Sun and Sommer, Roger D. and Grice, Kyle A.}, year={2016}, month={Aug}, pages={344–350} } @article{lambic_sommer_ison_2016, title={Transition-Metal Oxos as the Lewis Basic Component of Frustrated Lewis Pairs}, volume={138}, ISSN={["1520-5126"]}, DOI={10.1021/jacs.6b00705}, abstractNote={The reaction of oxorhenium complexes that incorporate diamidopyridine (DAP) ligands with B(C6F5)3 results in the formation of classical Lewis acid-base adducts. The adducts effectively catalyze the hydrogenation of a variety of unactivated olefins at 100 °C. Control reactions with these complexes or B(C6F5)3 alone did not yield any hydrogenated products under these conditions. Mechanistic studies suggest a frustrated Lewis pair is generated between the oxorhenium DAP complexes and B(C6F5)3, which is effective at olefin hydrogenation. Thus, we demonstrate for the first time that the incorporation of a transition-metal oxo in a frustrated Lewis pair can have a synergistic effect and results in enhanced catalytic activity.}, number={14}, journal={JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, publisher={American Chemical Society (ACS)}, author={Lambic, Nikola S. and Sommer, Roger D. and Ison, Elon A.}, year={2016}, month={Apr}, pages={4832–4842} } @article{lambic_sommer_ison_2017, title={Tuning Catalytic Activity in the Hydrogenation of Unactivated Olefins with Transition-Metal Oxos as the Lewis Base Component of Frustrated Lewis Pairs}, volume={7}, ISSN={["2155-5435"]}, DOI={10.1021/acscatal.6b03313}, abstractNote={The steric and electronic demands of the catalytic olefin hydrogenation of tert-butylethylene with oxorhenium/Lewis acid FLPs were evaluated. The sterics of the ligand were altered by installing bulkier isopropyl groups in the 2,6-positions of the diamidopyridine (DAP) ligand. Lewis acid/base adducts were not isolated for complexes with this ligand; however, species incorporating isopropyl groups were still active in catalytic hydrogenation. Modifications were also made to the Lewis acid, and catalytic reactions were performed with Piers’ borane, HB(C6F5)2, and the aluminum analogue Al(C6F5)3. The rate of catalytic hydrogenation was shown to strongly correlate with the size of the alkyl, aryl, or hydride ligand. This was confirmed by a linear Taft plot with the steric sensitivity factor δ = −0.57, which suggests that reaction rates are faster with sterically larger X substituents. These data were used to develop a catalyst ((MesDAP)Re(O)(Ph)/HB(C6F5)2) that achieved a TON of 840 for the hydrogenation of t...}, number={2}, journal={ACS CATALYSIS}, publisher={American Chemical Society (ACS)}, author={Lambic, Nikola S. and Sommer, Roger D. and Ison, Elon A.}, year={2017}, month={Feb}, pages={1170–1180} } @article{wilcox_losey_folmer_martin_zeller_sommer_2015, title={ChemInform Abstract: Crystalline and Liquid Structure of Zinc Chloride Trihydrate: A Unique Ionic Liquid.}, volume={46}, DOI={10.1002/chin.201516006}, abstractNote={AbstractThe H2O/ZnCl2 phase diagram is re‐investigated in the vicinity of 75 mol% H2O.}, number={16}, journal={ChemInform}, publisher={Wiley}, author={Wilcox, Robert J. and Losey, Bradley P. and Folmer, Jacob C. W. and Martin, James D. and Zeller, Matthias and Sommer, Roger}, year={2015}, month={Apr}, pages={no-no} } @article{wilcox_losey_folmer_martin_zeller_sommer_2015, title={Crystalline and Liquid Structure of Zinc Chloride Trihydrate: A Unique Ionic Liquid}, volume={54}, ISSN={0020-1669 1520-510X}, url={http://dx.doi.org/10.1021/ic5024532}, DOI={10.1021/ic5024532}, abstractNote={The water/ZnCl(2) phase diagram in the vicinity of the 75 mol % water composition is reported, demonstrating the existence of a congruently melting phase. Single crystals of this 3-equiv hydrate were grown, and the crystal structure of [Zn(OH(2))(6)][ZnCl(4)] was determined. Synchrotron X-ray and neutron diffraction and IR and Raman spectroscopy along with reverse Monte Carlo modeling demonstrate that a CsCl-type packing of the molecular ions persists into the liquid state. Consistent with the crystalline and liquid structural data, IR spectroscopy demonstrates that the O-H bonds of coordinated water do not exhibit strong intermolecular hydrogen ion bonding but are significantly weakened because of the water's coordination to Lewis acidic zinc ions. The O-H bond weakening makes this system a very strong hydrogen-bond donor, whereas the ionic packing along with the nonpolar geometry of the molecular ions makes this system a novel nonpolar, hydrogen-bonding, ionic liquid solvent.}, number={3}, journal={Inorganic Chemistry}, publisher={American Chemical Society (ACS)}, author={Wilcox, Robert J. and Losey, Bradley P. and Folmer, Jacob C. W. and Martin, James D. and Zeller, Matthias and Sommer, Roger}, year={2015}, month={Jan}, pages={1109–1119} } @article{stasiw_zhang_wang_dangi_stein_shultz_kirk_wojtas_sommer_2015, title={Determining the Conformational Landscape of a and pi Coupling Using para-Phenylene and "Aviram-Ratner" Bridges}, volume={137}, ISSN={["0002-7863"]}, DOI={10.1021/jacs.5b04629}, abstractNote={The torsional dependence of donor-bridge-acceptor (D-B-A) electronic coupling matrix elements (H(DA), determined from the magnetic exchange coupling, J) involving a spin SD = 1/2 metal semiquinone (Zn-SQ) donor and a spin S(A) = 1/2 nitronylnitroxide (NN) acceptor mediated by the σ/π-systems of para-phenylene and methyl-substituted para-phenylene bridges and by the σ-system of a bicyclo[2.2.2]octane (BCO) bridge are presented and discussed. The positions of methyl group(s) on the phenylene bridge allow for an experimentally determined evaluation of conformationally dependent (π) and conformationally independent (σ) contributions to the electronic and magnetic exchange couplings in these D-B-A biradicals at parity of D and A. The trend in the experimental magnetic exchange couplings are well described by CASSCF calculations. The torsional dependence of the pairwise exchange interactions are further illuminated in three-dimensional, "Ramachandran-type" plots that relate D-B and B-A torsions to both electronic and exchange couplings. Analysis of the magnetic data shows large variations in magnetic exchange (J ≈ 1-175 cm(-1)) and electronic coupling (H(DA) ≈ 450-6000 cm(-1)) as a function of bridge conformation relative to the donor and acceptor. This has allowed for an experimental determination of both the σ- and π-orbital contributions to the exchange and electronic couplings.}, number={29}, journal={JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, author={Stasiw, Daniel E. and Zhang, Jinyuan and Wang, Guangbin and Dangi, Ranjana and Stein, Benjamin W. and Shultz, David A. and Kirk, Martin L. and Wojtas, Lukasz and Sommer, Roger D.}, year={2015}, month={Jul}, pages={9222–9225} } @article{zhang_reddy_jiang_taniguchi_sommer_lindsey_2015, title={Elaboration of an unexplored substitution site in synthetic bacteriochlorins}, volume={19}, ISSN={["1099-1409"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84937975805&partnerID=MN8TOARS}, DOI={10.1142/s1088424615500534}, abstractNote={ The ability to introduce substituents at designated sites about the perimeter of synthetic bacteriochlorins – analogs of bacteriochlorophylls of bacterial photosynthesis – remains a subject of ongoing study. Here, the self-condensation of a dihydrodipyrrin-dioxolane affords a 5-[2-(trimethylsiloxy)ethoxy]bacteriochlorin. Like a 5-methoxybacteriochlorin, the latter undergoes regioselective bromination at the 15-position, directed by the distal 5-alkoxy group. On the other hand, attempted bromination of a bacteriochlorin bearing a 5-(2-hydroxyethoxy) group resulted in intramolecular ether formation with the adjacent β-pyrroline position to give an annulated dioxepine ring (confirmed by single-crystal X-ray structural analysis). The hydroxyethoxy group at the 5-position can be derivatized by acylation. In addition, the installation of auxochromes (methoxycarbonyl, phenylethynyl) at the β-pyrrole rings causes a substantial bathochromic shift of the long-wavelength absorption band (812 nm) and companion fluorescence emission band (821 nm). Taken together, the modification of the 5-substituent complements existing methods for installing a single substituent on the bacteriochlorin macrocycle. }, number={7}, journal={JOURNAL OF PORPHYRINS AND PHTHALOCYANINES}, publisher={World Scientific Pub Co Pte Lt}, author={Zhang, Nuonuo and Reddy, Kanumuri Ramesh and Jiang, Jianbing and Taniguchi, Masahiko and Sommer, Roger D. and Lindsey, Jonathan S.}, year={2015}, month={Jul}, pages={887–902} } @article{huang_wu_song_xu_smirnova_weare_sommer_2015, title={Ferromagnetic coupling in d(1)-d(3) linear oxido-bridged heterometallic complexes: ground-state models of metal-to-metal charge transfer excited states}, volume={44}, ISSN={["1477-9234"]}, DOI={10.1039/c5dt02719e}, abstractNote={Linear heterobimetallic oxido-bridged d1–d3 compounds are described which are proposed as models for magnetic coupling of MMCT excited states.}, number={43}, journal={DALTON TRANSACTIONS}, publisher={Royal Society of Chemistry (RSC)}, author={Huang, Tao and Wu, Xinyuan and Song, Xiao and Xu, Hao and Smirnova, Tatyana I. and Weare, Walter W. and Sommer, Roger D.}, year={2015}, pages={18937–18944} } @article{grice_kositarut_lawando_sommer_2015, title={Intramolecular C-H activation by air-stable Pt(II) phosphite complexes}, volume={799-800}, ISSN={["1872-8561"]}, DOI={10.1016/j.jorganchem.2015.09.031}, abstractNote={Air-stable L2PtMe2 complexes ligated by bulky aryl phosphite ligands were synthesized and characterized. The aryl phosphite ligands were prepared from substituted phenols and PCl3 or P(NMe2)3 without the use of an external base. The steric environment of the phenol controlled the number of substitutions at P(NMe2)3, resulting in selective formation of P(NMe2)(O-2,6-Me2C6H3)2. The phosphite ligands and their corresponding platinum(II) complexes were found to be air stable and robust. X-ray diffraction structures of the platinum(II) complexes were obtained in order to determine the steric environment around the metal centers. Thermolysis of the L2PtMe2 complexes in C6D6 at 100 °C results in loss of methane and formation of one major platinum-containing product in high yield. The products of thermolysis were found to be a result of cyclometalation by C–H activation of a sp3 C–H bond in the ligand to form a 6-membered ring, as confirmed by X-ray crystallography.}, journal={JOURNAL OF ORGANOMETALLIC CHEMISTRY}, publisher={Elsevier BV}, author={Grice, Kyle A. and Kositarut, Jason A. and Lawando, Anthony E. and Sommer, Roger D.}, year={2015}, month={Dec}, pages={201–207} } @article{choing_francis_clendenning_schuurman_sommer_tamblyn_weare_cuk_2015, title={Long-Lived LMCT in a d(0) Vanadium(V) Complex by Internal Conversion to a State of 3d(xy) Character}, volume={119}, ISSN={["1932-7447"]}, DOI={10.1021/acs.jpcc.5b00513}, abstractNote={The excited state dynamics of a d0 vanadium(V) oxido ligand-to-metal charge transfer (LMCT) complex, VOLF, were investigated via a combination of static optical and X-ray absorption (XAS) spectroscopy, transient optical absorption spectroscopy, and time-dependent density functional theory (TD-DFT). Upon excitation of the LMCT in the visible region, transient absorption data reveal that internal conversion traps the excited carrier population into a long-lived charge transfer state of 3dxy electron character, S1(dxy). The internal conversion is substantiated by an isosbestic point in the transient absorption data, two nearby charge transfer states that couple well by TD-DFT, multiple rates in the ground state recovery, and the decay kinetics of an excited state absorption with the energy of a d-d transition in O K-edge XAS spectra. The long lifetime (∼420 ps) of S1(dxy) can be ascribed to its poor optical and vibrational coupling to a distorted ground state (S0*) via a negligible electronic dipole transiti...}, number={30}, journal={JOURNAL OF PHYSICAL CHEMISTRY C}, author={Choing, Stephanie N. and Francis, Aaron J. and Clendenning, Graham and Schuurman, Michael S. and Sommer, Roger D. and Tamblyn, Isaac and Weare, Walter W. and Cuk, Tanja}, year={2015}, month={Jul}, pages={17029–17038} } @article{lehman_pahls_meredith_sommer_heinekey_cundari_ison_2015, title={Oxyfunctionalization with Cp*Ir-III(NHC)(Me)(CI) with O-2: Identification of a Rare Bimetallic Ir-IV mu-Oxo Intermediate}, volume={137}, ISSN={["0002-7863"]}, DOI={10.1021/ja512905t}, abstractNote={Methanol formation from [Cp*Ir(III)(NHC)Me(CD2Cl2)](+) occurs quantitatively at room temperature with air (O2) as the oxidant and ethanol as a proton source. A rare example of a diiridium bimetallic complex, [(Cp*Ir(NHC)Me)2(μ-O)][(BAr(F)4)2], 3, was isolated and shown to be an intermediate in this reaction. The electronic absorption spectrum of 3 features a broad observation at ∼660 nm, which is primarily responsible for its blue color. In addition, 3 is diamagnetic and can be characterized by NMR spectroscopy. Complex 3 was also characterized by X-ray crystallography and contains an Ir(IV)-O-Ir(IV) core in which two d(5) Ir(IV) centers are bridged by an oxo ligand. DFT and MCSCF calculations reveal several important features of the electronic structure of 3, most notably, that the μ-oxo bridge facilitates communication between the two Ir centers, and σ/π mixing yields a nonlinear arrangement of the μ-oxo core (Ir-O-Ir ∼ 150°) to facilitate oxygen atom transfer. The formation of 3 results from an Ir oxo/oxyl intermediate that may be described by two competing bonding models, which are close in energy and have formal Ir-O bond orders of 2 but differ markedly in their electronic structures. The radical traps TEMPO and 1,4-cyclohexadiene do not inhibit the formation of 3; however, methanol formation from 3 is inhibited by TEMPO. Isotope labeling studies confirmed the origin of the methyl group in the methanol product is the iridium-methyl bond in the [Cp*Ir(NHC)Me(CD2Cl2)][BAr(F)4] starting material. Isolation of the diiridium-containing product [(Cp*Ir(NHC)Cl)2][(BAr(F)4)2], 4, in high yields at the end of the reaction suggests that the Cp* and NHC ligands remain bound to the iridium and are not significantly degraded under reaction conditions.}, number={10}, journal={JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, author={Lehman, Matthew C. and Pahls, Dale R. and Meredith, Joseph M. and Sommer, Roger D. and Heinekey, D. Michael and Cundari, Thomas R. and Ison, Elon A.}, year={2015}, month={Mar}, pages={3574–3584} } @article{kulikov_siriwardane_mccandless_barnes_sevryugina_desousa_wu_sommer_novak_2015, title={Self-Assembly of n-Alkyl-and Aryl-Side Chain Ureas and Their Derivatives as Evidenced by SEM and X-ray Analysis}, volume={2015}, ISSN={["1099-0690"]}, DOI={10.1002/ejoc.201501242}, abstractNote={AbstractA small library of ureas and related compounds was synthesized and examined by scanning electron microscopy (SEM), single‐crystal X‐ray diffraction, powder X‐ray (pXRD), and polarized optical microscopy (POM) techniques in order to elucidate the factors controlling their self‐assembly in the solid state. Inspection of the 12 solid‐state structures revealed that molecules in the crystal lattice are held together by intermolecular H‐bonding, π–π stacking as well as C‐H/π interactions. The same interactions are likely responsible for the formation of supramolecular aggregates (e.g. sheet‐like assemblies, micro‐ and nano‐fibers, and the porous networks easily identifiable by SEM technique) and in certain cases led to the small molecules gelation.}, number={34}, journal={EUROPEAN JOURNAL OF ORGANIC CHEMISTRY}, author={Kulikov, Oleg V. and Siriwardane, Dumindika A. and McCandless, Gregory T. and Barnes, Charles and Sevryugina, Yulia V. and DeSousa, Joseph D. and Wu, Jingbo and Sommer, Roger and Novak, Bruce M.}, year={2015}, month={Dec}, pages={7511–7518} } @article{han_yun_borodin_seo_sommer_young_henderson_2015, title={Solvate Structures and Computational/Spectroscopic Characterization of LiPF6 Electrolytes}, volume={119}, DOI={10.1021/acs.jpcc.5b00826}, abstractNote={Crystal structures have been determined for both LiBF4 and HBF4 solvates: (acetonitrile)(2):LiBF4, (ethylene glycol diethyl ether)(1):LiBF4, (diethylene glycol diethyl ether)(1):LiBF4, (tetrahydrofuran)(1):LiBF4, (methyl methoxyacetate)(1):LiBF4, (succinonitrile)(1):LiBF4, (N,N,N',N '',N ''-pentamethyldiethylenetriamine)(1):HBF4, (N,N,N',N'-tetramethylethylenediamine)(3/2):HBF4, and (phenanthroline)(2):HBF4. These, as well as other known LiBF4 solvate structures, have been characterized by Raman vibrational spectroscopy to unambiguously assign the anion Raman band positions to specific forms of BF4-center dot center dot center dot Li+ cation coordination. In addition, complementary DFT calculations of BF4-center dot center dot center dot Li+ cation complexes have provided additional insight into the challenges associated with accurately interpreting the anion interactions from experimental Raman spectra. This information provides a crucial tool for the characterization of the ionic association interactions within electrolytes.}, number={16}, journal={The Journal of Physical Chemistry C}, publisher={American Chemical Society (ACS)}, author={Han, Sang-Don and Yun, Sung-Hyun and Borodin, Oleg and Seo, Daniel M. and Sommer, Roger D. and Young, Victor G. and Henderson, Wesley A.}, year={2015}, month={Apr}, pages={8492–8500} } @article{allen_lathrop_patel_moody_sommer_coombs_2015, title={Synthesis of 7-norbornenols via Diels-Alder cycloadditions of cyclopentadienol generated by decomposition of ferrocenium cation}, volume={56}, ISSN={["0040-4039"]}, DOI={10.1016/j.tetlet.2015.09.051}, abstractNote={Ferrocenium hexafluorophosphate, Cp2FePF6, was determined to be a convenient source of cyclopentadienol when stirred open to air in a mixture of acetonitrile and water. The cyclopentadienol was intercepted via Diels–Alder reaction with a variety of dienophiles to afford cycloadducts having 7-norbornenol cores. Reactions were stereoselective, producing single diastereomers from endo approach of the dienophile syn to the OH substituent of the cyclopentadienol.}, number={44}, journal={TETRAHEDRON LETTERS}, publisher={Elsevier BV}, author={Allen, Stacey K. and Lathrop, Thomas E. and Patel, Sweta B. and Moody, Deanna M. Harrell and Sommer, Roger D. and Coombs, Thomas C.}, year={2015}, month={Oct}, pages={6038–6042} } @article{wu_huang_lekich_sommer_weare_2015, title={Synthesis of Unsupported d(1)-d(x) dx Oxido-Bridged Heterobimetallic Complexes Containing V-IV: A New Direction for Metal-to-Metal Charge Transfer}, volume={54}, ISSN={["1520-510X"]}, DOI={10.1021/acs.inorgchem.5b00370}, abstractNote={Heterobimetallic complexes composed only of first-row transition metals [(TMTAA)V(IV)═O→M(II)Py5Me2](OTf)2 (TMTAA = 7,16-dihydro-6,8,15,17-tetramethyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecine; Py5Me2 = 2,6-bis(1,1-bis(2-pyridyl)ethyl)pyridine; M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II); OTf = trifluoromethanesulfonate) have been synthesized through a dative interaction between a terminal oxido and M(II) metal centers. This is the first series of V(IV)═O→M(II) heterobimetallic complexes containing an unsupported oxido bridge. Among these five complexes, only V(IV)═O→Fe(II) (3b) has a clear new absorption band upon formation of the dinuclear species (502 nm, ε = 1700 M(-1) cm(-1)). This feature is assigned to a metal-to-metal charge transfer (MMCT) transition from V(IV) to Fe(II), which forms a V(V)-O-Fe(I) excited state. This assignment is supported by electrochemical data, electronic absorption profiles, and resonance Raman spectroscopy and represents the first report of visible-light induced MMCT in a heterobimetallic oxido-bridged molecule where the electron originates on a d(1) metal center.}, number={11}, journal={INORGANIC CHEMISTRY}, publisher={American Chemical Society (ACS)}, author={Wu, Xinyuan and Huang, Tao and Lekich, Travis T. and Sommer, Roger D. and Weare, Walter W.}, year={2015}, month={Jun}, pages={5322–5328} } @article{falzone_nguyen_weare_sommer_boyle_2014, place={Cambridge, UK}, title={An unsupported metal hydroxide for the design of molecular μ-oxo bridged heterobimetallic complexes [Erratum to document cited in CA160:321591]}, volume={50}, number={67}, journal={Chemical Communications}, publisher={Chemical Communications}, author={Falzone, A.J. and Nguyen, J. and Weare, W.W. and Sommer, R.D. and Boyle, P.D.}, year={2014}, pages={9608} } @article{mcowen_delp_paillard_herriot_han_boyle_sommer_henderson_2014, title={Anion Coordination Interactions in Solvates with the Lithium Salts LiDCTA and LiTDI}, volume={118}, ISSN={["1932-7447"]}, DOI={10.1021/jp412601x}, abstractNote={Lithium 4,5-dicyano-1,2,3-triazolate (LiDCTA) and lithium 2-trifluoromethyl-4,5-dicyanoimidazole (LiTDI) are two salts proposed for lithium battery electrolyte applications, but little is known about the manner in which the DCTA– and TDI– anions coordinate Li+ cations. To explore this in depth, crystal structures are reported here for two solvates with LiDCTA—(G2)1:LiDCTA and (G1)1:LiDCTA—with diglyme and monoglyme, respectively; and seven solvates with LiTDI—(G1)2:LiTDI, (G2)2:LiTDI, (G3)1:LiTDI, (THF)1:LiTDI, (EC)1:LiTDI, (PC)1:LiTDI, and (DMC)1/2:LiTDI—with monoglyme, diglyme, triglyme, tetrahydrofuran, ethylene carbonate, propylene carbonate, and dimethyl carbonate, respectively. These latter solvate structures are compared with the previously reported acetonitrile (AN)2:LiTDI structure. The solvates indicate that the LiTDI salt is much less associated than the LiDCTA salt and that the ions in LiTDI, when aggregated in solvates, have a very similar TDI–···Li+ cation mode of coordination through both t...}, number={15}, journal={JOURNAL OF PHYSICAL CHEMISTRY C}, publisher={American Chemical Society (ACS)}, author={McOwen, Dennis W. and Delp, Samuel A. and Paillard, Elie and Herriot, Cristelle and Han, Sang-Don and Boyle, Paul D. and Sommer, Roger D. and Henderson, Wesley A.}, year={2014}, month={Apr}, pages={7781–7787} } @article{bartelmess_francis_el roz_castellano_weare_sommer_2014, title={Light-Driven Hydrogen Evolution by BODIPY-Sensitized Cobaloxime Catalysts}, volume={53}, ISSN={["1520-510X"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84899787366&partnerID=MN8TOARS}, DOI={10.1021/ic500218q}, abstractNote={We report four photocatalytically active cobaloxime complexes for light-driven hydrogen evolution. The cobaloxime catalysts are sensitized by different meso-pyridyl boron dipyrromethene (BODIPY) chromophores, bearing either two bromo- or iodo-substituents on the BODIPY core. The pyridine linker between the BODIPY and cobaloxime is further modified by a methyl substituent on the pyridine, influencing the stability and electronic properties of the cobaloxime catalyst and thus the photocatalytic efficiency of each system. Four cobaloxime catalyst complexes and three novel BODIPY chromophores are synthesized and characterized by absorption, fluorescence, infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry, and electrochemistry. Crystal structures for the BODIPY-cobaloxime complexes 2 and 3 are presented. In contrast to the photocatalytically inactive, nonhalogenated reference complex 1, the four newly reported molecules are active for photocatalytic hydrogen evolution, with a maximum turnover number (TON) of 30.9 mol equiv of H2 per catalyst for the meso-methylpyridyl 2,6-diiodo BODIPY-sensitized cobaloxime complex 5. We conclude that accessing the photoexcited triplet state of the BODIPY chromophore by introducing heavy atoms (i.e., bromine or iodine) is necessary for efficient electron transfer in this system, enabling catalytic hydrogen generation. In addition, relatively electron-donating pyridyl linkers improve the stability of the complex, increasing the overall TON for hydrogen production.}, number={9}, journal={INORGANIC CHEMISTRY}, publisher={American Chemical Society (ACS)}, author={Bartelmess, Juergen and Francis, Aaron J. and El Roz, Karim A. and Castellano, Felix N. and Weare, Walter W. and Sommer, Roger D.}, year={2014}, month={May}, pages={4527–4534} } @article{huang_wu_weare_sommer_2014, title={Mono-Oxido-Bridged Heterobimetallic and Heterotrimetallic Compounds Containing Titanium(IV) and Chromium(III)}, volume={2014}, ISSN={["1099-0682"]}, DOI={10.1002/ejic.201402800}, abstractNote={AbstractA series of oxido‐bridged heterobi‐ and heterotrimetallic complexes, [(tmtaa)Ti=O→Cr(Por)Cl] and [(tmtaa)Ti=O→Cr(Por)←O=Ti(tmtaa)]+ (tmtaa = 7,16‐dihydro‐6,8,15,17‐tetramethyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecine; Por = 5,10,15,20‐tetraarylporphyrin), have been synthesized. To the best of our knowledge, these complexes are the first structurally characterized examples to contain a Ti=O→Cr or Ti=O→Cr←O=Ti structural motif. Crystal structures of representative heterobimetallic compounds, including the Ti=O→Cr binuclear complex 2 and two separate trimers, [Ti=O→Cr←O=Ti]SbF6 (10) and [Ti=O→Cr←O=Ti]Cl (12), are reported. The bi‐ and trimetallic molecules have similar structural parameters, including Ti–O, Cr–O, and Ti–O–Cr bond lengths and angles with a linear Ti=O→Cr geometry. Magnetic studies showed that a high‐spin CrIII (S = 3/2) center is present in both the bi‐ and trinuclear molecules. The redox potentials for CrIV/III (ΔE = 320 mV) and Por/Por·– (ΔE = 260 mV) can be tuned by modifying the porphyrin ligand. By determining the thermodynamics and kinetics of the formation of these complexes by titration experiments and electrochemistry, it was found that the bi‐ and trimetallic species undergo isomerization in solution, allowing easy substitution of the apical chlorido ligand.}, number={33}, journal={EUROPEAN JOURNAL OF INORGANIC CHEMISTRY}, publisher={Wiley}, author={Huang, Tao and Wu, Xinyuan and Weare, Walter W. and Sommer, Roger D.}, year={2014}, month={Nov}, pages={5662–5674} } @article{lehman_boyle_sommer_ison_2014, title={Oxyfunctionalization with Cp*Ir-III(NHC)(Me)L Complexes}, volume={33}, ISSN={["1520-6041"]}, DOI={10.1021/om5007352}, abstractNote={A series of monomethyl Cp*IrIII complexes were synthesized and studied for the formation of methanol in water. Methanol yields of 75(4)% in the presence of O2 were obtained. From isotope labeling studies, it was determined that O2 is the source of the oxygen atom in the product. From kinetic studies, oxyfunctionalization appears to proceed by dissociation of an L-type ligand followed by O2 binding and insertion.}, number={19}, journal={ORGANOMETALLICS}, publisher={American Chemical Society (ACS)}, author={Lehman, Matthew C. and Boyle, Paul D. and Sommer, Roger D. and Ison, Elon A.}, year={2014}, month={Oct}, pages={5081–5084} } @article{liu_ptaszek_mass_minkler_sommer_bhaumik_lindsey_2014, title={Regioselective β-pyrrolic electrophilic substitution of hydrodipyrrin–dialkylboron complexes facilitates access to synthetic models for chlorophyll f}, volume={38}, ISSN={1144-0546 1369-9261}, url={http://dx.doi.org/10.1039/C3NJ01508D}, DOI={10.1039/c3nj01508d}, abstractNote={Substituents in ring A of chlorophylls can exert profound effects on spectral properties. A de novo route to synthetic chlorins employs a tetrahydrodipyrrin reactant containing pyrrole and pyrroline rings. Complexation of the tetrahydrodipyrrin with a dialkylboron motif caused electrophilic substitution (bromination, formylation) to proceed predominantly at the β7- rather than α-position of the pyrrole ring, whereas an analogous dihydrodipyrrin underwent substitution equally at the 7- and 8-positions. The fully unsaturated dipyrrin–difluoroboron complex is known to undergo electrophilic substitution at the 8-position. The 7-position of the hydrodipyrrin ultimately gives rise to substituents at the chlorin 2-position (ring A), which heretofore has been little accessed. The position of substitution was confirmed by four single-crystal X-ray structures. Two isomeric formylchlorins were prepared by Pd-mediated carbonylation of the corresponding bromochlorins. Access to a 2-formylchlorin relied on bromination of the tetrahydrodipyrrin–dibutylboron complex, whereas a 3-formylchlorin was prepared by installation of the bromo group in the earliest precursor, pyrrole-2-carboxaldehyde. The two formylchlorins differ in absorption spectral properties: the Qy absorption maximum is 654 or 664 nm for the 2- or 3-formylchlorin, respectively. The synthetic formylchlorins provide initial models for understanding the strong red absorption of native 2- or 3-formylchlorophylls (f and d).}, number={4}, journal={New Journal of Chemistry}, publisher={Royal Society of Chemistry (RSC)}, author={Liu, Mengran and Ptaszek, Marcin and Mass, Olga and Minkler, Daniel F. and Sommer, Roger D. and Bhaumik, Jayeeta and Lindsey, Jonathan S.}, year={2014}, pages={1717} } @article{seo_boyle_sommer_daubert_borodin_henderson_2014, title={Solvate Structures and Spectroscopic Characterization of LiTFSI Electrolytes}, volume={118}, ISSN={["1520-6106"]}, DOI={10.1021/jp505006x}, abstractNote={A Raman spectroscopic evaluation of numerous crystalline solvates with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI or LiN(SO2CF3)2) has been conducted over a wide temperature range. Four new crystalline solvate structures-(PHEN)3:LiTFSI, (2,9-DMPHEN)2:LiTFSI, (G3)1:LiTFSI and (2,6-DMPy)1/2:LiTFSI with phenanthroline, 2,9-dimethyl[1,10]phenanthroline, triglyme, and 2,6-dimethylpyridine, respectively-have been determined to aid in this study. The spectroscopic data have been correlated with varying modes of TFSI(-)···Li(+) cation coordination within the solvate structures to create an electrolyte characterization tool to facilitate the Raman band deconvolution assignments for the determination of ionic association interactions within electrolytes containing LiTFSI. It is found, however, that significant difficulties may be encountered when identifying the distributions of specific forms of TFSI(-) anion coordination present in liquid electrolyte mixtures due to the wide range of TFSI(-)···Li(+) cation interactions possible and the overlap of the corresponding spectroscopic data signatures.}, number={47}, journal={JOURNAL OF PHYSICAL CHEMISTRY B}, publisher={American Chemical Society (ACS)}, author={Seo, Daniel M. and Boyle, Paul D. and Sommer, Roger D. and Daubert, James S. and Borodin, Oleg and Henderson, Wesley A.}, year={2014}, month={Nov}, pages={13601–13608} } @article{kirk_shultz_stasiw_lewis_wang_brannen_sommer_boyle_2014, title={Superexchange Contributions to Distance Dependence of Electron Transfer/Transport: Exchange and Electronic Coupling in Oligo(para-Phenylene)- and Oligo(2,5-Thiophene)-Bridged Donor-Bridge-Acceptor Biradical Complexes [Erratum to document cited in CA159:719548]}, volume={136}, ISSN={0002-7863 1520-5126}, url={http://dx.doi.org/10.1021/JA500971X}, DOI={10.1021/ja500971x}, abstractNote={ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionNEXTORIGINAL ARTICLEThis notice is a correctionCorrection to "Superexchange Contributions to Distance Dependence of Electron Transfer/Transport: Exchange and Electronic Coupling in Oligo(para-Phenylene)- and Oligo(2,5-Thiophene)-Bridged Donor–Bridge–Acceptor Biradical Complexes"Martin L. Kirk*, David A. Shultz*, Daniel E. Stasiw, Geoffry F. Lewis, Guangbin Wang, Candice L. Brannen, Roger D. Sommer, and Paul D. BoyleCite this: J. Am. Chem. Soc. 2014, 136, 10, 4089Publication Date (Web):February 28, 2014Publication History Published online28 February 2014Published inissue 12 March 2014https://pubs.acs.org/doi/10.1021/ja500971xhttps://doi.org/10.1021/ja500971xcorrectionACS PublicationsCopyright © 2014 American Chemical Society. This publication is available under these Terms of Use. Request reuse permissions This publication is free to access through this site. Learn MoreArticle Views1241Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. 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Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail PDF (121 KB) Get e-Alertsclose Get e-Alerts}, number={10}, journal={Journal of American Chemical Society}, publisher={American Chemical Society (ACS)}, author={Kirk, M.L. and Shultz, D.A. and Stasiw, D.E. and Lewis, G.F. and Wang, G. and Brannen, C.L. and Sommer, R.D. and Boyle, P.D.}, year={2014}, pages={4089} } @article{king_sommer_watkins-curry_chan_maggard_2015, title={Synthesis, Structure, and Thermal Instability of the Cu2Ta4O11 Phase}, volume={15}, ISSN={["1528-7505"]}, DOI={10.1021/cg500987c}, abstractNote={The Cu(I)-tantalate, Cu2Ta4O11, has been synthesized by flux methods in high purity and characterized by single-crystal X-ray diffraction (space group R3c (167), a = 6.219(2) A, c = 37.107(1) A). The compound is a new n = 1 member of the Cu(I)-tantalate CuxTa3n+1O8n+3 series of structures and can be prepared in a molten CuCl flux within a relatively low temperature range of ∼625–700 °C, in comparison to the synthesis of Cu5Ta11O30 (n = 1.5) and Cu3Ta7O19 (n = 2) at ∼800 to 1000 °C. The structure consists of layers of TaO7 pentagonal bipyramids that alternate with layers of isolated TaO6 octahedra and linearly coordinated Cu(I) cations. An increasing Cu-site vacancy across this series from Cu3Ta7O19 (100%), to Cu5Ta11O30 (83.3%), to Cu2Ta4O11 (66.7%) leads to an increasing fraction of O atoms that are not locally charge balanced by the Ta(V)/Cu(I) cations and thus yields decreased stability of Cu2Ta4O11. Thermal analysis shows that Cu2Ta4O11 decomposes in air or under flowing nitrogen at temperatures abov...}, number={2}, journal={CRYSTAL GROWTH & DESIGN}, publisher={American Chemical Society (ACS)}, author={King, Nacole and Sommer, Roger D. and Watkins-Curry, Pilanda and Chan, Julia Y. and Maggard, Paul A.}, year={2015}, month={Feb}, pages={552–558} } @article{frasco_sommer_ison_2015, title={ortho-C–H Activation of Thiobenzoic Acid: Synthesis, Characterization, and Reactivity of Iridium Thiobenzoate Complexes}, volume={34}, ISSN={["1520-6041"]}, DOI={10.1021/om501115u}, abstractNote={Cp*Ir(Me2SO)(OAc)2, 1, has been shown to activate an ortho-C–H-bond of thiobenzoic acid in methanol at 100 °C to form the novel iridium complex (Cp*Ir(S(O)CC6H4))2, 5. Unlike the similar reaction with benzoic acid, this new iridium complex exists as a dimer with bridging sulfur ligands. To our knowledge, this is the first example of metal facilitated C–H activation of thiobenzoic acid. Complex 5 reacted with CO to form Cp*Ir(CO)(S(O)CC6H4), 6. Complex 5 was also shown to react with the electrophilic methyl reagents methyl iodide and methyl triflate. The reaction with methyl iodide resulted in the formation of Cp*Ir(I)(SMe(O)CC6H4), 7, while the reaction with methyl triflate resulted in the bimetallic complex [(Cp*Ir(SMe(O)CC6H4)(Cp*Ir(S(O)CC6H4)][OTf], 8. The order of reactivity with electrophilic methyl reagents was MeOTf > MeI >MeOAc, which reflects the nucleophilic character of the sulfoxyl group of the cyclometalated thiobenzoate ligand. Attempts at cyclization with complex 5 and olefins and alkynes w...}, number={1}, journal={Organometallics}, publisher={American Chemical Society (ACS)}, author={Frasco, D.A. and Sommer, R.D. and Ison, E.A.}, year={2015}, pages={275–279} } @article{falzone_nguyen_weare_sommer_boyle_2014, title={An unsupported metal hydroxide for the design of molecular mu-oxo bridged heterobimetallic complexes}, volume={50}, ISSN={["1364-548X"]}, DOI={10.1039/c3cc49066a}, abstractNote={A terminal and unsupported chromium(iii) hydroxide is reported.}, number={17}, journal={CHEMICAL COMMUNICATIONS}, author={Falzone, A. J. and Nguyen, J. and Weare, W. W. and Sommer, R. D. and Boyle, P. D.}, year={2014}, pages={2139–2141} } @article{kirk_shultz_stasiw_lewis_wang_brannen_sommer_boyle_2013, title={Superexchange Contributions to Distance Dependence of Electron Transfer/Transport: Exchange and Electronic Coupling in Oligo(para-Phenylene)- and Oligo(2,5-Thiophene)-Bridged Donor–Bridge–Acceptor Biradical Complexes}, volume={135}, ISSN={0002-7863 1520-5126}, url={http://dx.doi.org/10.1021/JA4081887}, DOI={10.1021/ja4081887}, abstractNote={The preparation and characterization of three new donor-bridge-acceptor biradical complexes are described. Using variable-temperature magnetic susceptibility, EPR hyperfine coupling constants, and the results of X-ray crystal structures, we evaluate both exchange and electronic couplings as a function of bridge length for two quintessential molecular bridges: oligo(para-phenylene), β = 0.39 Å(-1) and oligo(2,5-thiophene), β = 0.22 Å(-1). This report represents the first direct comparison of exchange/electronic couplings and distance attenuation parameters (β) for these bridges. The work provides a direct measurement of superexchange contributions to β, with no contribution from incoherent hopping. The different β values determined for oligo(para-phenylene) and oligo(2,5-thiophene) are due primarily to the D-B energy gap, Δ, rather than bridge-bridge electronic couplings, H(BB). This is supported by the fact that the H(BB) values extracted from the experimental data for oligo(para-phenylene) (H(BB) = 11,400 cm(-1)) and oligo(2,5-thiophene) (12,300 cm(-1)) differ by <10%. The results presented here offer unique insight into the intrinsic molecular factors that govern H(DA) and β, which are important for understanding the electronic origin of electron transfer and electron transport mediated by molecular bridges.}, number={45}, journal={Journal of the American Chemical Society}, publisher={American Chemical Society (ACS)}, author={Kirk, Martin L. and Shultz, David A. and Stasiw, Daniel E. and Lewis, Geoffrey F. and Wang, Guangbin and Brannen, Candice L. and Sommer, Roger D. and Boyle, Paul D.}, year={2013}, month={Nov}, pages={17144–17154} } @article{bartelmess_weare_sommer_2013, title={Synthesis, characterization and structural investigation of novel meso-pyridyl BODIPY–cobaloxime complexes}, volume={42}, DOI={10.1039/c3dt51849c}, abstractNote={We report the synthesis of four boron-dipyrromethene (BODIPY) sensitized cobaloxime complexes as structural models of light-driven proton reduction catalysts. The BODIPY chromophore is covalently linked to the cobaloxime via a pyridine molecule in the meso-position of the BODIPY. Electron withdrawing or donating substituents on the pyridine (e.g. chloro- or methyl-groups) allow a comparison of the influence of these substituents on cobaloxime-BODIPY interactions. This includes altering the overall stability of the complexes and tuning the catalytically relevant Co(II/III) redox couple over a range of 220 mV, which will assist in the design of future cobaloxime-chromophore complexes. All complexes were characterized using electrochemistry, electronic absorption and fluorescence spectroscopy. Additionally, we present crystal structures of the four new BODIPY-cobaloxime complexes and elucidate the influence of the structural modifications. We found that these compounds produce sub-stoichiometric quantities of hydrogen under standard photon-driven hydrogen evolving conditions.}, number={41}, journal={Dalton Transactions}, publisher={Royal Society of Chemistry (RSC)}, author={Bartelmess, Juergen and Weare, Walter W. and Sommer, Roger D.}, year={2013}, pages={14883} } @article{spore_rizzo_noll_sommer_2010, title={A growing family: New structures of coordination polymers containing adamantane-shaped phosphorus–nitrogen cage ligands}, volume={364}, DOI={10.1016/j.ica.2010.08.052}, abstractNote={Two new structurally characterized coordination polymers containing the P4(NR)6 ligand system are described. A convenient one-pot synthesis of P4(NR)6 (R = benzyl) via reaction of lithiated primary amine with phosphorus trichloride demonstrates an expanded scope for the preparation of this adamantane-type structure. Reactions of P4(NR)6 (R = Et, Bn) with cuprous iodide yield different products due to the differences in steric demands of the ligands.}, number={1}, journal={Inorganica Chimica Acta}, publisher={Elsevier BV}, author={Spore, Alex B. and Rizzo, Natalie M. and Noll, Bruce C. and Sommer, Roger D.}, year={2010}, pages={261–265} }