%0 Journal Article %1 Ladwig.1992 %A Ladwig, Monika %A Kaim, Wolfgang. %D 1992 %J Journal of Organometallic Chemistry %K bipyridine catalytic complex complex;electronic electrochem gas hydrogen hydrogen;iridium intermediate iridium photocatalysis prodn prodn;water reaction shift structure %N 1 %P 79--90 %R 10.1016/0022-328X(92)80055-3 %T Electronic structure of catalytic intermediates for production of hydrogen: (C5Me5)Ir(bpy) and its conjugated acid %V 439 %X Chem. and electrochem. two-electron redn. of the IrIII complex (C5Me5)ClIr(bpy)(Cl), bpy = 2,2'-bipyridine, yields highly reactive (C5Me5)Ir(bpy), the conjugated acid of which was postulated as an intermediate in the homogeneous photo-catalysis of the water gas shift reaction. Cyclovoltammetric, UV/Vis-, 1H- and 13C-NMR-spectroscopic measurements in aprotic and protic solvents have revealed the electronic structures of the neutral \dqIrI\dq complex and of (C5Me5)IrH(bpy)+. In the very electron-rich neutral complex there is even more p back donation to bpy than in the analogous compd. (C5Me5)Rh(bpy), as is evident from the very neg. redn. potential, the high field NMR shifts for the bpy ligand, and from the unusually structured absorption spectrum in the visible. As a consequence, the photo- and electro-chem. behavior of (C5Me5)IrH(bpy)+ and (C5Me5)Ir(bpy) is best described by assigning a (-I) oxidn. state to the electron-buffering 2,2'-bipyridine ligand. on SciFinder(R)

@article{Ladwig.1992, abstract = {Chem. and electrochem. two-electron redn. of the IrIII complex [(C5Me5)ClIr(bpy)](Cl), bpy = 2,2'-bipyridine, yields highly reactive (C5Me5)Ir(bpy), the conjugated acid of which was postulated as an intermediate in the homogeneous photo-catalysis of the water gas shift reaction. Cyclovoltammetric, UV/Vis-, 1H- and 13C-NMR-spectroscopic measurements in aprotic and protic solvents have revealed the electronic structures of the neutral {\dq}IrI{\dq} complex and of [(C5Me5)IrH(bpy)]+. In the very electron-rich neutral complex there is even more \textgreek{p} back donation to bpy than in the analogous compd. (C5Me5)Rh(bpy), as is evident from the very neg. redn. potential, the high field NMR shifts for the bpy ligand, and from the unusually structured absorption spectrum in the visible. As a consequence, the photo- and electro-chem. behavior of [(C5Me5)IrH(bpy)]+ and [(C5Me5)Ir(bpy)] is best described by assigning a (-I) oxidn. state to the electron-buffering 2,2'-bipyridine ligand. [on SciFinder(R)]}, added-at = {2022-06-15T11:26:56.000+0200}, author = {Ladwig, Monika and Kaim, Wolfgang.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/200795e0decd61cf05268f83088420601/huebleriac}, doi = {10.1016/0022-328X(92)80055-3}, interhash = {5a008a7541360b77ffec9d8e92731c4c}, intrahash = {00795e0decd61cf05268f83088420601}, journal = {Journal of Organometallic Chemistry}, keywords = {bipyridine catalytic complex complex;electronic electrochem gas hydrogen hydrogen;iridium intermediate iridium photocatalysis prodn prodn;water reaction shift structure}, number = 1, pages = {79--90}, timestamp = {2022-06-15T09:26:56.000+0200}, title = {Electronic structure of catalytic intermediates for production of hydrogen: (C5Me5)Ir(bpy) and its conjugated acid}, volume = 439, year = 1992 }