%0 Journal Article %1 Klein.1998 %A Klein, Axel %A Hasenzahl, Steffen %A Kaim, Wolfgang %A Fiedler, Jan. %D 1998 %J Organometallics %K bridged cyclic dinuclear ligand organo organoplatinum organoplatinum;mixed organoplatinum;platinum prepn;spectroelectrochem pyrazine tetrazine valent voltammetry %N 16 %P 3532--3538 %R 10.1021/OM980107J %T On the Question of Mixed-Valent States in Ligand-Bridged Dinuclear Organoplatinum Compounds RkPt(m-L)PtRkn, k = 2 or 4 %V 17 %X Sym. dinuclear complexes between the bis-bidentate bridging ligands m-L (m-L = 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine (bptz) or 2,5-bis(1-phenyliminoethyl)pyrazine (bpip)) and the organoplatinum fragments PtMes2 (Mes = mesityl), PtMe2, or PtMe4 were synthesized as deeply colored compds. Low-energy charge-transfer transitions from metal d orbitals (PtII) or metal-carbon s bond combinations (PtIV) to low-lying p* orbitals of the p acceptor ligands are responsible for long-wavelength absorption maxima lmax(CT) \textgreater 700 nm. UV/Vis and EPR spectroelectrochem. results for reversible redn. processes indicate the formation of PtIV2(m-L.bul.-) and PtII2(m-L.bul.-) species, however, the latter exhibit a significant metal contribution according to a PtII/PtI formulation. Cyclic voltammetry reveals that the remarkable system Mes2Pt(m-bptz)PtMes2n forms an enormously stabilized radical anion (n = 1-) with DE1/2 = 1250 V and Kc = 1021.2 and a PtIII/PtII mixed-valent state (n = 1+) with DE1/2 = 80 mV and Kc = 23. This small Kc value is attributed to the predominantly ds orbital character of the redox orbitals on the Pt(II) centers. on SciFinder(R)

@article{Klein.1998, abstract = {Sym. dinuclear complexes between the bis-bidentate bridging ligands \textgreek{m}-L (\textgreek{m}-L = 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine (bptz) or 2,5-bis(1-phenyliminoethyl)pyrazine (bpip)) and the organoplatinum fragments PtMes2 (Mes = mesityl), PtMe2, or PtMe4 were synthesized as deeply colored compds. Low-energy charge-transfer transitions from metal d orbitals (PtII) or metal-carbon \textgreek{s} bond combinations (PtIV) to low-lying \textgreek{p}* orbitals of the \textgreek{p} acceptor ligands are responsible for long-wavelength absorption maxima \textgreek{l}max(CT) {\textgreater} 700 nm. UV/Vis and EPR spectroelectrochem. results for reversible redn. processes indicate the formation of [PtIV]2(\textgreek{m}-L.bul.-) and [PtII]2(\textgreek{m}-L.bul.-) species, however, the latter exhibit a significant metal contribution according to a PtII/PtI formulation. Cyclic voltammetry reveals that the remarkable system [Mes2Pt(\textgreek{m}-bptz)PtMes2]n forms an enormously stabilized radical anion (n = 1-) with \textgreek{D}E1/2 = 1250 V and Kc = 1021.2 and a PtIII/PtII mixed-valent state (n = 1+) with \textgreek{D}E1/2 = 80 mV and Kc = 23. This small Kc value is attributed to the predominantly d\textgreek{s} orbital character of the redox orbitals on the Pt(II) centers. [on SciFinder(R)]}, added-at = {2022-06-15T11:26:56.000+0200}, author = {Klein, Axel and Hasenzahl, Steffen and Kaim, Wolfgang and Fiedler, Jan.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/2f2aeaa5757900a4a49031ef478443597/huebleriac}, doi = {10.1021/OM980107J}, interhash = {f66557ac0849d82f406804c46a47e889}, intrahash = {f2aeaa5757900a4a49031ef478443597}, issn = {0276-7333}, journal = {Organometallics}, keywords = {bridged cyclic dinuclear ligand organo organoplatinum organoplatinum;mixed organoplatinum;platinum prepn;spectroelectrochem pyrazine tetrazine valent voltammetry}, number = 16, pages = {3532--3538}, timestamp = {2022-06-15T09:26:56.000+0200}, title = {On the Question of Mixed-Valent States in Ligand-Bridged Dinuclear Organoplatinum Compounds [RkPt(\textgreek{m}-L)PtRk]n, k = 2 or 4}, volume = 17, year = 1998 }