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)
%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 = {2019-07-15T13:41:23.000+0200},
author = {Klein, Axel and Hasenzahl, Steffen and Kaim, Wolfgang and Fiedler, Jan.},
biburl = {https://puma.ub.uni-stuttgart.de/bibtex/2f2aeaa5757900a4a49031ef478443597/b_schwederski},
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 = {2019-07-15T11:42:10.000+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
}