%0 Journal Article %1 Ghumaan.2007 %A Ghumaan, Sandeep %A Sarkar, Biprajit %A Patil, Mahendra P. %A Fiedler, Jan %A Sunoj, Raghavan B. %A Kaim, Wolfgang %A Lahiri, Goutam Kumar. %D 2007 %J Polyhedron %K DFT MO acac diquinoxalinophenazine electrochem frontier mixed prepn redox;spectroelectrochem ruthenium substituted trinuclear trinuclear;EPR trinuclear;mixed trinuclear;ruthenium valence %N 13 %P 3409--3418 %R 10.1016/j.poly.2007.03.030 %T Multiple one-electron oxidation and reduction of trinuclear bis(2,4-pentanedionato)ruthenium complexes with substituted diquinoxalino2,3-a:2',3'-cphenazine ligands %V 26 %X The complexes (m3-L1/L2)Ru(acac)23, acac- = 2,4-pentanedionato, L1 = 2,3,8,9,14,15-hexachlorodiquinoxalino2,3-a:2',3'-cphenazine and L2 = 2,3,8,9,14,15- hexamethyldiquinoxalino2,3-a:2',3'-cphenazine, undergo stepwise 1-electron oxidn. involving a total of three electrons and stepwise 1-electron redn. with three (L2) or four electrons (L1). All reversibly accessible states were characterized by UV-visible-NIR spectroelectrochem. Oxidn. leads to mixed-valent intermediates (μ3-L)Ru(acac)23+ and (μ3-L)Ru(acac)232+ of which the RuIIIRuIIRuII combinations exhibit higher comproportionation consts. Kc than the RuIIIRuIIIRuII states - in contrast to a previous report for the unsubstituted parent systems (μ3-L3)Ru(acac)23+/2+, L3 = diquinoxalino2,3-a:2',3'-cphenazine. No conspicuous intervalence charge transfer absorptions were obsd. for the mixed-valent intermediates in the visible to near-IR regions. The monocations and monoanions were characterized by EPR spectroscopy, revealing rhombic Ru(III) type signals for the former. Electron addn. produces Ru(II) complexes of the reduced forms of the ligands L; a high resoln. EPR spectrum with 14N and 35,37Cl hyperfine coupling and negligible g anisotropy was found for (μ3-L1)Ru(acac)23-. DFT calcns. of (m3-L1)Ru(acac)23 confirm several ligand-centered low-lying unoccupied MOs for redn. and several metal-based high-lying occupied MOs for electron withdrawal, resulting in low-energy metal-to-ligand charge transfer (MLCT) transitions. on SciFinder(R)

@article{Ghumaan.2007, abstract = {The complexes (\textgreek{m}3-L1/L2)[Ru(acac)2]3, acac- = 2,4-pentanedionato, L1 = 2,3,8,9,14,15-hexachlorodiquinoxalino[2,3-a:2',3'-c]phenazine and L2 = 2,3,8,9,14,15- hexamethyldiquinoxalino[2,3-a:2',3'-c]phenazine, undergo stepwise 1-electron oxidn. involving a total of three electrons and stepwise 1-electron redn. with three (L2) or four electrons (L1). All reversibly accessible states were characterized by UV-visible-NIR spectroelectrochem. Oxidn. leads to mixed-valent intermediates {(μ3-L)[Ru(acac)2]3}+ and {(μ3-L)[Ru(acac)2]3}2+ of which the RuIIIRuIIRuII combinations exhibit higher comproportionation consts. Kc than the RuIIIRuIIIRuII states - in contrast to a previous report for the unsubstituted parent systems {(μ3-L3)[Ru(acac)2]3}+/2+, L3 = diquinoxalino[2,3-a:2',3'-c]phenazine. No conspicuous intervalence charge transfer absorptions were obsd. for the mixed-valent intermediates in the visible to near-IR regions. The monocations and monoanions were characterized by EPR spectroscopy, revealing rhombic Ru(III) type signals for the former. Electron addn. produces Ru(II) complexes of the reduced forms of the ligands L; a high resoln. EPR spectrum with 14N and 35,37Cl hyperfine coupling and negligible g anisotropy was found for {(μ3-L1)[Ru(acac)2]3}-. DFT calcns. of (\textgreek{m}3-L1)[Ru(acac)2]3 confirm several ligand-centered low-lying unoccupied MOs for redn. and several metal-based high-lying occupied MOs for electron withdrawal, resulting in low-energy metal-to-ligand charge transfer (MLCT) transitions. [on SciFinder(R)]}, added-at = {2022-06-15T11:26:56.000+0200}, author = {Ghumaan, Sandeep and Sarkar, Biprajit and Patil, Mahendra P. and Fiedler, Jan and Sunoj, Raghavan B. and Kaim, Wolfgang and Lahiri, Goutam Kumar.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/2490986865dddb6ee76d60542e9cdccc2/huebleriac}, doi = {10.1016/j.poly.2007.03.030}, interhash = {44600712e1f0e24903ea1fa0a428d847}, intrahash = {490986865dddb6ee76d60542e9cdccc2}, issn = {0277-5387}, journal = {Polyhedron}, keywords = {DFT MO acac diquinoxalinophenazine electrochem frontier mixed prepn redox;spectroelectrochem ruthenium substituted trinuclear trinuclear;EPR trinuclear;mixed trinuclear;ruthenium valence}, number = 13, pages = {3409--3418}, timestamp = {2022-06-15T09:26:56.000+0200}, title = {Multiple one-electron oxidation and reduction of trinuclear bis(2,4-pentanedionato)ruthenium complexes with substituted diquinoxalino[2,3-a:2',3'-c]phenazine ligands}, volume = 26, year = 2007 }