%0 Journal Article %1 Samanta.2008 %A Samanta, Subhas %A Singh, Priti %A Fiedler, Jan %A Zalis, Stanislav %A Kaim, Wolfgang %A Goswami, Sreebrata. %D 2008 %J Inorganic Chemistry %K 8 ESR UV crystal diradical electrochem metal osmium oxidn phenylaminophenylazopyridine phenylaminophenylazopyridine;group prepn ruthenium singlet spectroelectrochem;phenylaminophenylazopyridine structure %N 5 %P 1625--1633 %R 10.1021/ic702301a %T Singlet Diradical Complexes of Ruthenium and Osmium: Geometrical and Electronic Structures and their Unexpected Changes on Oxidation %V 47 %X Reaction of HL, HLa (2-[(2-N-phenylamino)phenylazo]pyridine), HLb (2-[2-N-(4-methylphenyl)aminophenylazo]pyridine), or HLc (2-[2-N-(4-chlorophenyl)aminophenylazo]pyridine), with KRuO4 or OsO4 and PPh3 under exhaustive deoxygenation (PPh3 $\rightarrow$ OPPh3) yields diamagnetic compds. ML2. Crystal structure detn. for M(La)2 indicates the ligand radical dianion state, L.bul.2-, as evident from a typical N-N bond length of $\sim$1.33 \AA for a 1-electron reduced azo function. The resulting spin-coupled complexes, MIV(L.bul.2-)2, can be oxidized in two reversible 1-electron steps, as probed by cyclic voltammetry and UV-visible-NIR spectroelectrochem. The paramagnetic intermediates, [M(La)2]+, are distinguished by intense NIR absorption, largely metal-centered spin as revealed by EPR, and, in the case of [Os(La)2]I3, by crystallog. detd. shortening of the N=N bond to $\sim$1.30 \AA, corresponding to a coordinated unreduced azo function. Thus, oxidn. of MIV(L.bul.2-)2 involves partial redn. of the metal in [MIII(L-)2]+ because intramol. double electron transfer is offsetting the external charge removal. D.-functional theory calcns. were employed to confirm the structural features and to support the spectroscopic assignments. [on SciFinder(R)]

@article{Samanta.2008, abstract = {Reaction of HL, HLa (2-[(2-N-phenylamino)phenylazo]pyridine), HLb (2-[{2-N-(4-methylphenyl)amino}phenylazo]pyridine), or HLc (2-[{2-N-(4-chlorophenyl)amino}phenylazo]pyridine), with KRuO4 or OsO4 and PPh3 under exhaustive deoxygenation (PPh3 $\rightarrow$ OPPh3) yields diamagnetic compds. ML2. Crystal structure detn. for M(La)2 indicates the ligand radical dianion state, L.bul.2-, as evident from a typical N-N bond length of $\sim$1.33 {\AA} for a 1-electron reduced azo function. The resulting spin-coupled complexes, MIV(L.bul.2-)2, can be oxidized in two reversible 1-electron steps, as probed by cyclic voltammetry and UV-visible-NIR spectroelectrochem. The paramagnetic intermediates, [M(La)2]+, are distinguished by intense NIR absorption, largely metal-centered spin as revealed by EPR, and, in the case of [Os(La)2]I3, by crystallog. detd. shortening of the N=N bond to $\sim$1.30 {\AA}, corresponding to a coordinated unreduced azo function. Thus, oxidn. of MIV(L.bul.2-)2 involves partial redn. of the metal in [MIII(L-)2]+ because intramol. double electron transfer is offsetting the external charge removal. D.-functional theory calcns. were employed to confirm the structural features and to support the spectroscopic assignments. [on SciFinder(R)]}, added-at = {2022-06-15T11:26:56.000+0200}, author = {Samanta, Subhas and Singh, Priti and Fiedler, Jan and Zalis, Stanislav and Kaim, Wolfgang and Goswami, Sreebrata.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/28950c41ae4f0d549e5eaf027172d5bcf/huebleriac}, doi = {10.1021/ic702301a}, interhash = {1b1d485edea96886ada4586681e9f47f}, intrahash = {8950c41ae4f0d549e5eaf027172d5bcf}, issn = {0020-1669}, journal = {Inorganic Chemistry}, keywords = {8 ESR UV crystal diradical electrochem metal osmium oxidn phenylaminophenylazopyridine phenylaminophenylazopyridine;group prepn ruthenium singlet spectroelectrochem;phenylaminophenylazopyridine structure}, number = 5, pages = {1625--1633}, timestamp = {2022-06-15T09:26:56.000+0200}, title = {Singlet Diradical Complexes of Ruthenium and Osmium: Geometrical and Electronic Structures and their Unexpected Changes on Oxidation}, volume = 47, year = 2008 }