%0 Journal Article %1 Grupp.2014 %A Grupp, Anita %A Bubrin, Martina %A Ehret, Fabian %A Zeng, Qiang %A Hartl, Frantisek %A Kvapilova, Hana %A Zalis, Stanislav %A Kaim, Wolfgang. %D 2014 %J European Journal of Inorganic Chemistry %K ESR acetylacetonato alpha charge complex configuration crystal diazabutadiene excited ground ligand metal mol pentanedionate prepn radical ruthenium spectroelectrochem;diimine state structure;stabilization transfer %N 1 %P 110--119 %R 10.1002/ejic.201301206 %T RuII(a-diimine) or RuIII(a-diimine·-)? Structural, Spectroscopic, and Theoretical Evidence for the Stabilization of a Prominent Metal-to-Ligand Charge-Transfer Excited-State Configuration in the Ground State %V 2014 %X The new compds. [Ru(R-DAB)(acac)2] (R-DAB = 1,4-diorganyl-1,4-diazabuta-1,3-diene; R = tert-Bu, 4-methoxyphenyl, 2,6-dimethylphenyl; acac- = 2,4-pentanedionate) exhibit intrachelate ring bond lengths 1.297 \textless d(CN) \textless 1.344 \AA and 1.382 \textless d(CC) \textless 1.425 \AA, which suggest a RuIII(R-DAB·-) oxidn. state formulation. This notion is confirmed by the negligible solvatochromism of the intense (e $\approx$ 104M-1 cm-1) charge-transfer absorption band in the visible region and by DFT calcns. Oxidn. of the compds. occurs mainly at the R-DAB·- radical ligand to produce UV/Vis/NIR and ESR spectroelectrochem. detectable RuIII species, whereas the redn. proceeds less reversibly and yields predominantly (R-DAB)-ligand-based spin for the 4-methoxyphenyl deriv., measured at low temp. The results are discussed with respect to metal-to-ligand charge-transfer (MLCT) excited states of conventional (a-diimine)ruthenium(II) complexes and in view of other (a-diimine)metal complexes with ambiguous oxidn.-state assignments. [on SciFinder(R)]

@article{Grupp.2014, abstract = {The new compds. [Ru(R-DAB)(acac)2] (R-DAB = 1,4-diorganyl-1,4-diazabuta-1,3-diene; R = tert-Bu, 4-methoxyphenyl, 2,6-dimethylphenyl; acac- = 2,4-pentanedionate) exhibit intrachelate ring bond lengths 1.297 {\textless} d(CN) {\textless} 1.344 {\AA} and 1.382 {\textless} d(CC) {\textless} 1.425 {\AA}, which suggest a RuIII(R-DAB·-) oxidn. state formulation. This notion is confirmed by the negligible solvatochromism of the intense (\textgreek{e} $\approx$ 104M-1 cm-1) charge-transfer absorption band in the visible region and by DFT calcns. Oxidn. of the compds. occurs mainly at the R-DAB·- radical ligand to produce UV/Vis/NIR and ESR spectroelectrochem. detectable RuIII species, whereas the redn. proceeds less reversibly and yields predominantly (R-DAB)-ligand-based spin for the 4-methoxyphenyl deriv., measured at low temp. The results are discussed with respect to metal-to-ligand charge-transfer (MLCT) excited states of conventional (\textgreek{a}-diimine)ruthenium(II) complexes and in view of other (\textgreek{a}-diimine)metal complexes with ambiguous oxidn.-state assignments. [on SciFinder(R)]}, added-at = {2022-06-15T11:26:56.000+0200}, author = {Grupp, Anita and Bubrin, Martina and Ehret, Fabian and Zeng, Qiang and Hartl, Frantisek and Kvapilova, Hana and Zalis, Stanislav and Kaim, Wolfgang.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/2fd6a76bb6f8275d754e6e0a79d439fc0/huebleriac}, doi = {10.1002/ejic.201301206}, interhash = {6694fd3f06b3bd97e0da48d1c78fed4d}, intrahash = {fd6a76bb6f8275d754e6e0a79d439fc0}, issn = {1434-1948}, journal = {European Journal of Inorganic Chemistry}, keywords = {ESR acetylacetonato alpha charge complex configuration crystal diazabutadiene excited ground ligand metal mol pentanedionate prepn radical ruthenium spectroelectrochem;diimine state structure;stabilization transfer}, number = 1, pages = {110--119}, timestamp = {2022-06-15T09:26:56.000+0200}, title = {RuII(\textgreek{a}-diimine) or RuIII(\textgreek{a}-diimine·-)? Structural, Spectroscopic, and Theoretical Evidence for the Stabilization of a Prominent Metal-to-Ligand Charge-Transfer Excited-State Configuration in the Ground State}, volume = 2014, year = 2014 }