%0 Journal Article %1 Kundu.2011 %A Kundu, Tanaya %A Sarkar, Biprajit %A Mondal, Tapan Kumar %A Mobin, Shaikh M. %A Urbanos, Francisco A. %A Fiedler, Jan %A Jimenez-Aparicio, Reyes %A Kaim, Wolfgang %A Lahiri, Goutam Kumar. %D 2011 %J Inorganic Chemistry %K absorption complex complex;ESR complex;IR complex;electronic complex;prepn complex;spin coupling dinuclear electrochem pyridylpyrazine ruthenium semiquinone structure %N 11 %P 4753--4763 %R 10.1021/ic102280q %T Redox-Rich Spin-Spin-Coupled Semiquinoneruthenium Dimers with Intense Near-IR Absorption %V 50 %X Using the RuCl(m-tppz)ClRu2+ tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine platform for bridging two o-quinone/catecholate two-step redox systems (unsubstituted, Qn, or 3,5-di-tert-butyl-substituted, DTBQn), the authors have obtained the stable complexes (Q·-)RuIICl(m-tppz)ClRuII(Q·-) (1) and the structurally characterized (DTBQ·-)RuIICl(m-tppz)ClRuII(DTBQ·-) (2). The compds. exhibit mostly quinone-ligand-based redox activity within a narrow potential range, high-intensity near-IR absorptions (lmax $\approx$ 920 nm; e \textgreater 50,000 M-1/cm-1), and variable intra- and intermol. spin-spin interactions. D. functional theory calcns., EPR, and spectroelectrochem. results (UV-visible-near-IR region) for three one-electron-redn. and two one-electron-oxidn. processes were used to probe the electronic structures of the systems in the various accessible valence states. EPR spectroscopy of the singly charged doublet species showed semiquinone-type response for 1+, 2+, and 2-, while 1 exhibits more metal based spin, a consequence of the easier redn. of Q as compared to DTBQ. Comparison with the analogous redox series involving a more basic N-phenyliminoquinone ligand reveals significant differences related to the shifted redox potentials, different space requirements, and different interactions between the metals and the quinone-type ligands. As a result, the tppz bridge is reduced here only after full redn. of the terminal quinone ligands to their catecholate states. on SciFinder(R)

@article{Kundu.2011, abstract = {Using the [RuCl(\textgreek{m}-tppz)ClRu]2+ [tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine] platform for bridging two o-quinone/catecholate two-step redox systems (unsubstituted, Qn, or 3,5-di-tert-butyl-substituted, DTBQn), the authors have obtained the stable complexes [(Q·-)RuIICl(\textgreek{m}-tppz)ClRuII(Q·-)] (1) and the structurally characterized [(DTBQ·-)RuIICl(\textgreek{m}-tppz)ClRuII(DTBQ·-)] (2). The compds. exhibit mostly quinone-ligand-based redox activity within a narrow potential range, high-intensity near-IR absorptions (\textgreek{l}max $\approx$ 920 nm; \textgreek{e} {\textgreater} 50,000 M-1/cm-1), and variable intra- and intermol. spin-spin interactions. D. functional theory calcns., EPR, and spectroelectrochem. results (UV-visible-near-IR region) for three one-electron-redn. and two one-electron-oxidn. processes were used to probe the electronic structures of the systems in the various accessible valence states. EPR spectroscopy of the singly charged doublet species showed semiquinone-type response for 1+, 2+, and 2-, while 1 exhibits more metal based spin, a consequence of the easier redn. of Q as compared to DTBQ. Comparison with the analogous redox series involving a more basic N-phenyliminoquinone ligand reveals significant differences related to the shifted redox potentials, different space requirements, and different interactions between the metals and the quinone-type ligands. As a result, the tppz bridge is reduced here only after full redn. of the terminal quinone ligands to their catecholate states. [on SciFinder(R)]}, added-at = {2022-06-15T11:26:56.000+0200}, author = {Kundu, Tanaya and Sarkar, Biprajit and Mondal, Tapan Kumar and Mobin, Shaikh M. and Urbanos, Francisco A. and Fiedler, Jan and Jimenez-Aparicio, Reyes and Kaim, Wolfgang and Lahiri, Goutam Kumar.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/2338be0fa314190200bf11a0cc12276c0/huebleriac}, doi = {10.1021/ic102280q}, interhash = {9f88ecda7a1357a059cd58e6f61050ef}, intrahash = {338be0fa314190200bf11a0cc12276c0}, issn = {0020-1669}, journal = {Inorganic Chemistry}, keywords = {absorption complex complex;ESR complex;IR complex;electronic complex;prepn complex;spin coupling dinuclear electrochem pyridylpyrazine ruthenium semiquinone structure}, number = 11, pages = {4753--4763}, timestamp = {2022-06-15T09:26:56.000+0200}, title = {Redox-Rich Spin-Spin-Coupled Semiquinoneruthenium Dimers with Intense Near-IR Absorption}, volume = 50, year = 2011 }