Reaction of HL, HLa (2-(2-N-phenylamino)phenylazopyridine), HLb (2-2-N-(4-methylphenyl)aminophenylazopyridine), or HLc (2-2-N-(4-chlorophenyl)aminophenylazopyridine), 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)2I3, 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)
%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)phenylazopyridine), HLb (2-2-N-(4-methylphenyl)aminophenylazopyridine), or HLc (2-2-N-(4-chlorophenyl)aminophenylazopyridine), 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)2I3, 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 = {2019-07-15T13:41:23.000+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/b_schwederski},
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 = {2019-07-15T11:42:10.000+0200},
title = {Singlet Diradical Complexes of Ruthenium and Osmium: Geometrical and Electronic Structures and their Unexpected Changes on Oxidation},
volume = 47,
year = 2008
}