%0 Journal Article %1 Waldhoer.1995 %A Waldhoer, Eberhard %A Poppe, Juergen %A Kaim, Wolfgang %A Cutin, Edgardo H. %A Garcia Posse, Monica E. %A Katz, Nestor E. %D 1995 %J Inorganic Chemistry %K azobispyridine azobispyridine;ESR azobispyridine;electrochem bipyrazine charge complex;MLCT cyano cyano;iron iron redox ruthenium transfer %N 11 %P 3093--3096 %R 10.1021/ic00115a042 %T EPR Evidence for Low-Lying MLCT States in Tetracyanoiron and -ruthenium Complexes with Strongly p-Accepting Chelate Ligands. Comparison with Isoelectronic Tetracarbonylmetal Species %V 34 %X [(Bpz)M(CN)4]2- (M = Fe, Ru) and [(abpy)Fe(CN)4]2- with the strongly p-accepting chelate ligands 2,2'-bipyrazine (bpz) and 2,2'-azobis(pyridine) (abpy) were prepd. as potassium or tetrabutylammonium salts and were characterized by IR and UV/visible absorption spectroscopy. Cyclic voltammetry in acetonitrile, DMF, or water revealed reversible 1-electron oxidn. processes, while the redn. waves showed reversibility only in aprotic solvents. EPR studies of the spectroelectrochem. generated (1-) and (3-) states confirm the MLCT formulation for the lowest excited states of the (2-) precursor complexes by showing typical low-spin Fe(III) signals of the oxidized species [(abpy)Fe(CN)4]- and partially hyperfine-structured spectra for the reduced forms [(bpz)M(CN)4]3-. The latter are clearly tetracyanoiron(II) or -ruthenium(II) complexes of the corresponding anion radical acceptor ligands and are thus isoelectronic with monoanionic tetracarbonylchromium(0) or -molybdenum(0) radial complexes. [on SciFinder(R)]

@article{Waldhoer.1995, abstract = {[(Bpz)M(CN)4]2- (M = Fe, Ru) and [(abpy)Fe(CN)4]2- with the strongly \textgreek{p}-accepting chelate ligands 2,2'-bipyrazine (bpz) and 2,2'-azobis(pyridine) (abpy) were prepd. as potassium or tetrabutylammonium salts and were characterized by IR and UV/visible absorption spectroscopy. Cyclic voltammetry in acetonitrile, DMF, or water revealed reversible 1-electron oxidn. processes, while the redn. waves showed reversibility only in aprotic solvents. EPR studies of the spectroelectrochem. generated (1-) and (3-) states confirm the MLCT formulation for the lowest excited states of the (2-) precursor complexes by showing typical low-spin Fe(III) signals of the oxidized species [(abpy)Fe(CN)4]- and partially hyperfine-structured spectra for the reduced forms [(bpz)M(CN)4]3-. The latter are clearly tetracyanoiron(II) or -ruthenium(II) complexes of the corresponding anion radical acceptor ligands and are thus isoelectronic with monoanionic tetracarbonylchromium(0) or -molybdenum(0) radial complexes. [on SciFinder(R)]}, added-at = {2022-06-15T11:26:56.000+0200}, author = {Waldhoer, Eberhard and Poppe, Juergen and Kaim, Wolfgang and Cutin, Edgardo H. and {Garcia Posse}, Monica E. and Katz, Nestor E.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/281850ec891415299ea0be8dcd0e869f7/huebleriac}, doi = {10.1021/ic00115a042}, interhash = {08bbb0e60c4711b4345ee5a00348ec3b}, intrahash = {81850ec891415299ea0be8dcd0e869f7}, issn = {0020-1669}, journal = {Inorganic Chemistry}, keywords = {azobispyridine azobispyridine;ESR azobispyridine;electrochem bipyrazine charge complex;MLCT cyano cyano;iron iron redox ruthenium transfer}, number = 11, pages = {3093--3096}, timestamp = {2022-06-15T09:26:56.000+0200}, title = {EPR Evidence for Low-Lying MLCT States in Tetracyanoiron and -ruthenium Complexes with Strongly \textgreek{p}-Accepting Chelate Ligands. Comparison with Isoelectronic Tetracarbonylmetal Species}, volume = 34, year = 1995 }