@article{anariba_tiznado_diers_schmidt_muresan_lindsey_zaera_bocian_2008, title={Comprehensive characterization of hybrid junctions comprised of a porphyrin monolayer sandwiched between a coinage metal overlayer and a Si(100) substrate}, volume={112}, ISSN={["1932-7447"]}, DOI={10.1021/jp802428y}, abstractNote={The promise of molecular electronics has stimulated a variety of approaches for making hybrid junctions wherein molecules are sandwiched between two metal contacts or a metal and a semiconductor contact. However, the fate of molecules subsequent to deposition of a top metal contact has generally not been well characterized. Toward this goal, the interaction of evaporated Cu, Ag, and Au films deposited in varying thicknesses (3, 5, and 8 nm) on a series of monolayer-coverage porphyrins covalently attached to Si(100) substrates was investigated. Each porphyrin contains a triallyl tripod attached to the porphyrin via a p-phenylene unit, which anchors the porphyrin to the Si(100) substrate via hydrosilylation of the allyl groups. All of the porphyrins are Zn chelates bearing meso p-tolyl substituents orthogonal (lateral) to the tripodal surface anchor, but contain different substituents in the meso position opposite (distal) to the surface anchor, p-tolyl, α,α,α-trifluoro-p-tolyl, pentafluorophenyl, or p-cyan...}, number={25}, journal={JOURNAL OF PHYSICAL CHEMISTRY C}, author={Anariba, Franklin and Tiznado, Hugo and Diers, James R. and Schmidt, Izabela and Muresan, Ana Z. and Lindsey, Jonathan S. and Zaera, Francisco and Bocian, David F.}, year={2008}, month={Jun}, pages={9474–9485} }
 @article{muresan_lindsey_2008, title={Design and synthesis of water-soluble bioconjugatable trans-AB-porphyrins}, volume={64}, ISSN={["1464-5416"]}, DOI={10.1016/j.tet.2008.08.096}, abstractNote={Three free base porphyrins have been prepared that bear a polar and facially encumbering 2,4,6-tris-(carboxymethoxy)phenyl motif at one meso (5-) position. The only other substituent (15-position) comprises phenyl, formyl, or p-aminophenyl. The porphyrins exhibit solubility in water (or aqueous buffer solutions) at pH ≥7 and concentrations >1 mM at room temperature. The concise syntheses, water solubility, and bioconjugatable handle make these porphyrin constructs suitable for biological applications.}, number={50}, journal={TETRAHEDRON}, author={Muresan, Ana Z. and Lindsey, Jonathan S.}, year={2008}, month={Dec}, pages={11440–11448} }
 @misc{lindsey_muthukumaran_sharada_muresan_youngblood_2008, title={Metal complexation of 1-acyldipyrromethanes and porphyrins formed therefrom}, volume={7,323,561}, number={2008 Jan. 29}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Lindsey, J. S. and Muthukumaran, K. and Sharada, D. S. and Muresan, A. Z. and Youngblood, W. J.}, year={2008} }
 @article{anariba_schmidt_muresan_lindsey_bocian_2008, title={Metal-molecule interactions upon deposition of copper overlayers on reactively functionalized porphyrin monolayers on Si(100)}, volume={24}, ISSN={["0743-7463"]}, DOI={10.1021/la800472c}, abstractNote={The interaction of evaporated Cu deposited on a series of porphyrins in monolayers covalently attached to Si(100) substrates was investigated using cyclic voltammetry and FTIR spectroscopy. Each porphyrin contains a triallyl tripod attached to the porphyrin via a p-phenylene unit. The tripod anchors the porphyrin to the Si(100) substrate via hydrosilylation of the allyl groups. Two of the porphyrins are Zn chelates that possess meso p-cyanophenyl substituentsone, ZnP-CND, contains a single group opposite (distal) to the tripodal surface anchor, whereas the other, ZnP-CNL, contains two groups orthogonal (lateral) to the surface anchor. A third Zn porphyrin, ZnP, containing nonreactive p-tolyl groups at all three nonanchoring meso positions, was examined for comparison. The fourth porphyrin, FbP-HD, is a metal-free species (free base) that contains nonreactive phenyl (distal) and p-tolyl groups (lateral) at the three nonanchoring meso positions. The fifth porphyrin, CuP-HD, is the Cu chelate of FbP-HD, and serves as a reference complex for evaluating the effects of Cu metal deposition onto FbP-HD. The studies indicate that all of the porphyrin monolayers are robust under the conditions of Cu deposition, experiencing no noticeable degradation. In addition, the Cu metal does not penetrate through the monolayer to form electrically conductive filaments. For the ZnP-CND monolayers, the deposited Cu quantitatively reacts/complexes with the distal cyano group. In contrast, for the ZnP-CNL monolayers no reaction/complexation of the lateral cyano groups is observed. For the FbP-HD monolayers, Cu deposition results in quantitative insertion of Cu into the free base porphyrin. Collectively, the studies demonstrate that porphyrin monolayers are amenable to direct deposition of Cu overlayers and that functionalization of the porphyrins can be used to mediate the attributes of the metal-molecule junction.}, number={13}, journal={LANGMUIR}, author={Anariba, Franklin and Schmidt, Lzabela and Muresan, Ana Z. and Lindsey, Jonathan S. and Bocian, David F.}, year={2008}, month={Jul}, pages={6698–6704} }
 @article{muresan_thamyongkit_diers_holten_lindsey_bocian_2008, title={Regiospecifically alpha-C-13-labeled porphyrins for studies of ground-state hole transfer in multiporphyrin arrays}, volume={73}, ISSN={["0022-3263"]}, DOI={10.1021/jo8012836}, abstractNote={Insight into the electronic communication between the individual constituents of multicomponent molecular architectures is essential for the rational design of molecular electronic and/or photonic devices. To clock the ground-state hole/electron-transfer process in oxidized multiporphyrin architectures, a p-diphenylethyne-linked zinc porphyrin dyad was prepared wherein one porphyrin bears two (13)C atoms and the other porphyrin is unlabeled. The (13)C atoms are located at the 1- and 9-positions (alpha-carbons symmetrically disposed to the position of linker attachment), which are sites of electron/spin density in the a(1u) HOMO of the porphyrin. The (13)C labels were introduced by reaction of KS(13)CN with allyl bromide to give the allyl isothiocyanate, which upon Trofimov pyrrole synthesis followed by methylation gave 2-(methylthio)pyrrole-2-(13)C. Reaction of the latter with paraformaldehyde followed by hydrodesulfurization gave dipyrromethane-1,9-(13)C, which upon condensation with a dipyrromethane-1,9-dicarbinol bearing three pentafluorophenyl groups gave the tris(pentafluorophenyl)porphyrin bearing (13)C labels at the 1,9-positions and an unsubstituted meso (5-) position. Zinc insertion, bromination at the 5-position, and Suzuki coupling with an unlabeled porphyrin bearing a suitably functionalized diphenylethyne linker gave the regiospecifically labeled zinc porphyrin dyad. Examination of the monocation of the isotopically labeled dyad via electron paramagnetic resonance (EPR) spectroscopy (and comparison with the monocations of benchmark monomers, where hole transfer cannot occur) showed that the hole transfer between porphyrin constituents of the dyad is slow (<10(6) s(-1)) on the EPR time scale at room temperature. The slow rate stems from the a(1u) HOMO of the electron-deficient porphyrins, which has a node at the site of linker connection. In contrast, analogous dyads of electron-rich porphyrins (wherein the HOMO is a(2u) and has a lobe at the site of linker connection) studied previously exhibit rates of hole transfer that are fast (>5 x 10(7) s(-1)) on the EPR time scale at room temperature.}, number={18}, journal={JOURNAL OF ORGANIC CHEMISTRY}, author={Muresan, Ana Z. and Thamyongkit, Patchanita and Diers, James R. and Holten, Dewey and Lindsey, Jonathan S. and Bocian, David F.}, year={2008}, month={Sep}, pages={6947–6959} }
 @article{thamyongkit_muresan_diers_holten_bocian_lindsey_2007, title={Meso-C-13-labeled porphyrins for studies of ground-state hole transfer in multiporphyrin arrays}, volume={72}, ISSN={["0022-3263"]}, DOI={10.1021/jo070593x}, abstractNote={Understanding electronic communication among interacting chromophores provides the foundation for a variety of applications. The ground-state electronic communication in diphenylethyne-linked zinc-porphyrin dyads has been investigated by a novel molecular design strategy that entails introduction of a 13C-atom (*) at specific sites of the porphyrins where there is substantial electron density in the relevant frontier (highest occupied) molecular orbital. The site of 13C substitution is at a meso-position, either the site of attachment of the linker (proximal, "P") or the site trans to the linker (distal, "D"). The substituents (R) at the non-linking meso-positions are mesityl, tridec-7-yl ("swallowtail"), or p-tolyl groups. Altogether five isotopically labeled porphyrin dyads have been prepared. The hole/electron-transfer properties of one-electron oxidized dyads have been examined by electron paramagnetic resonance (EPR) spectroscopy. The introduction of the meso-13C label provides a "clock" (via the hyperfine interactions) that allows investigation of a time scale for hole transfer that is 3-4 times shorter than that provided by the natural abundance 14N nuclei of the pyrrole nitrogen atoms. The EPR studies indicate that the hole transfer, which has been previously shown to be fast on the time scale of the 14N hyperfine clock ( approximately 220 ns), remains fast on the time scale of the 13C hyperfine clock ( approximately 50 ns).}, number={14}, journal={JOURNAL OF ORGANIC CHEMISTRY}, author={Thamyongkit, Patchanita and Muresan, Ana Z. and Diers, James R. and Holten, Dewey and Bocian, David F. and Lindsey, Jonathan S.}, year={2007}, month={Jul}, pages={5207–5217} }
 @article{kulikov_schmidt_muresan_lee_bocian_lindsey_2007, title={Synthesis of porphyrins for metal deposition studies in molecular information storage applications}, volume={11}, ISSN={["1099-1409"]}, DOI={10.1142/S1088424607000801}, abstractNote={ Porphyrins may serve as the active charge-storage medium in memory chips. A series of 14 porphyrins (trans-A2B2, trans-AB2C, or A4 type; free base, copper or zinc chelate) has been synthesized for investigation of metal deposition on porphyrin monolayers. Each trans-AB2C porphyrin is equipped with a surface attachment group and a distal functional group (or flanking functional groups). The surface attachment groups include S-acetylthiomethyl, hydroxymethyl, TMS-ethynyl, allyl, and triallylmethyl; the functional groups include amino, cyano, dipyrrin-5-yl, formyl, and nitro; all of which are attached to the p-position of a porphyrin meso-phenyl group. Two non-redox-active triallylmethyl-substituted arenes were also prepared for use as control compounds. }, number={10}, journal={JOURNAL OF PORPHYRINS AND PHTHALOCYANINES}, author={Kulikov, Oleg V. and Schmidt, Izabela and Muresan, Ana Z. and Lee, Marcia A. -P. and Bocian, David F. and Lindsey, Jonathan S.}, year={2007}, pages={699–712} }
 @article{chen_zhang_wasinger_attenkofer_jennings_muresan_lindsey_2007, title={Tracking electrons and atoms in a photoexcited metalloporphyrin by X-ray transient absorption spectroscopy}, volume={129}, ISSN={["0002-7863"]}, DOI={10.1021/ja072979v}, abstractNote={Simultaneously tracking electronic and molecular structures of a photoexcited metalloporphyrin, present for only 200 ps in a dilute solution, has been realized using X-ray transient absorption spectroscopy (XTA). Using laser pulses as excitation sources and delayed X-ray pulses as probes, we were able to identify the excited state electronic configuration of a nickel porphyrin as singly occupied 3dx2-y2 and 3dz2 molecular orbitals (MOs) with an energy gap of ∼2.2 eV, and energy shifts 4pz MOs to 1.5 eV higher relative to that of the ground state, and an expanded porphyrin ring characterized by lengthening of Ni−N and Ni−C bonds. Moreover, kinetic XTA signals at different X-ray photon energies demonstrate the capability for acquiring the correlation and coherence between different optically excited states with the same technique. These results provide guidance for theoretical calculations as well as insightful understanding of optically excited states that play important roles in photochemical processes.}, number={31}, journal={JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, author={Chen, Lin X. and Zhang, Xiaoyi and Wasinger, Erik C. and Attenkofer, Klaus and Jennings, Guy and Muresan, Ana Z. and Lindsey, Jonathan S.}, year={2007}, month={Aug}, pages={9616-+} }
 @article{zhang_wasinger_muresan_attenkofer_jennings_lindsey_chen_2007, title={Ultrafast stimulated emission and structural dynamics in nickel porphyrins}, volume={111}, ISSN={["1089-5639"]}, DOI={10.1021/jp0751763}, abstractNote={The excited-state structural dynamics of nickel(II)tetrakis(2,4,6-trimethylphenyl)porphyrin (NiTMP) and nickel(II)tetrakis(tridec-7-yl)porphyrin (NiSWTP) in a toluene solution were investigated via ultrafast transient optical absorption spectroscopy. An ultrashort stimulated emission between 620 and 670 nm from the S1 state was observed in both nickel porphyrins only when this state was directly generated via Q-band excitation, whereas such a stimulated emission was absent under B (Soret)-band excitation. Because the stimulated emission in the spectral region occurs only from the S1 state, this photoexcitation-wavelength-dependent behavior of Ni(II) porphyrins is attributed to a faster intersystem crossing from the S2 state than the internal conversion S2 --> S1. The dynamics of the excited-state pathways involving the (pi, pi*) and (d, d) states varies with the meso-substituted peripheral groups, which is attributed to the nickel porphyrin macrocycle distortion from a planar configuration. Evidence for intramolecular vibrational relaxation within 2 ps and vibrational cooling in 6-20 ps of a (d, d) excited state has been established for NiTMP and NiSWTP. Finally, the lifetimes of the vibrationally relaxed (d, d) state also depend on the nature of the peripheral groups, decreasing from 200 ps for NiTMP to 100 ps for the bulkier NiSWTP.}, number={46}, journal={JOURNAL OF PHYSICAL CHEMISTRY A}, author={Zhang, Xiaoyi and Wasinger, Erik C. and Muresan, Ana Z. and Attenkofer, Klaus and Jennings, Guy and Lindsey, Jonathan S. and Chen, Lin X.}, year={2007}, month={Nov}, pages={11736–11742} }
 @article{sharada_muresan_muthukumaran_lindsey_2005, title={Direct synthesis of palladium porphyrins from acyldipyrromethanes}, volume={70}, ISSN={["1520-6904"]}, DOI={10.1021/jo050120v}, abstractNote={[reaction: see text] Palladium porphyrins are valuable photosensitizers and luminescent agents in biology and materials chemistry. New methodology is described wherein a 1-acyldipyrromethane is converted into the palladium chelate of a trans-A(2)B(2) porphyrin via a one-flask reaction. The reaction entails self-condensation of the 1-acyldipyrromethane in refluxing ethanol containing KOH (5-10 mol equiv) and Pd(CH(3)CN)(2)Cl(2) (0.6 mol equiv) exposed to air. This direct route to palladium porphyrins is more expedient than the four steps of the traditional synthesis: (1) reduction of the 1-acyldipyrromethane; (2) acid-catalyzed condensation; (3) oxidation of the porphyrinogen intermediate; and (4) metal insertion. The new synthesis requires neither acid nor DDQ and formally entails only a 2e(-) + 2H(+) oxidation overall versus the traditional multistep synthesis which requires a 2e(-) + 2H(+) reduction per each 1-acyldipyrromethane (4e(-) + 4H(+) overall) followed by a 6e(-) + 6H(+) oxidation. The analogous reaction of a 1,9-diacyldipyrromethane and a dipyrromethane also gives the palladium porphyrin. Seven palladium porphyrins have been prepared in yields of 25-57%. The direct route also can be used with Cu(OAc)(2).H(2)O to give the copper porphyrin albeit in low yield. In summary, this methodology readily affords palladium porphyrins directly from acyldipyrromethanes.}, number={9}, journal={JOURNAL OF ORGANIC CHEMISTRY}, author={Sharada, DS and Muresan, AZ and Muthukumaran, K and Lindsey, JS}, year={2005}, month={Apr}, pages={3500–3510} }