@article{burns_huang_weare_bartolotti_wang_yao_li_franzen_2015, title={Aerobic oxidation of beta-isophorone by tetraphenylporphYrin catalysts in pyridine solution}, volume={410}, ISSN={["1873-314X"]}, DOI={10.1016/j.molcata.2015.09.015}, abstractNote={A kinetic study was conducted using five metallo-tetraphenylporphyrins (MTPPs) as catalysts for the aerobic oxidation reaction of β-isophorone (β-IP) to ketoisophorone (KIP). The oxidation reaction catalyzed by MTPPs (M = Cr, Mn, Fe, Co and Cu) was observed over a seven hour period under a range of experimental conditions. Changes in the specificity of conversion of reactant to the product, KIP, and the main side-product, α-isophorone (α-IP), were observed at temperatures ranging from 60 °C to 75 °C, in solvents with varying compositions of pyridine and β-IP, with different MTPP catalysts, oxygen gas flow rates, and solution agitation frequencies. Control experiments show that MTPP catalysts modestly increase the rate of KIP formation, but significantly improve specificity through the apparent suppression of α-IP formation. Analysis revealed that MnTPP (CH3COO−) produced the highest product specificity ratio [KIP]/[α-IP]. Given that all of the metals were in the 3+ oxidation state in this study and there was no observed binding by O2 to any of the MTPP catalysts, the catalytic mechanism is suggested to involve the binding of β-IP to the MTPP metal center. Binding of β-IP is most favorable when pyridine is the trans ligand, but β-IP is also observed to weakly bind when trans to acetate in the MnTPP adduct. This conclusion is supported by electronic absorption spectroscopy, resonance Raman spectroscopy and density functional theory (DFT) calculations. The role played by the catalyst appears to be the activation of hydrogen abstraction following the substrate's ligation to the metal, rather than the more traditional role of MTPPs as O2 activation catalysts by ligation of diatomic O2. β-IP oxidation is an example of a case where the catalyst appears to have a more important role for improving the specificity of the reaction (through decreasing side-product formation) rather than increasing the rate of product formation.}, journal={JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL}, author={Burns, Eric and Huang, Tao and Weare, Walter W. and Bartolotti, Libero and Wang, Xinyu and Yao, Jia and Li, Haoran and Franzen, Stefan}, year={2015}, month={Dec}, pages={110–120} }
 @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{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{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={Abstract}, 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} }