PUMA publications for /user/b_schwederski/dinuclear;electronicMon Jul 15 13:41:23 CEST 2019Inorganica Chimica Acta1-2269--278Electronic and molecular structure of 2,2'-bipyrimidine-bridged bis(organoplatinum) complexes in various oxidation states. Radical-bridged diplatinum species and the absence of a Pt(III)/Pt(II) mixed-valent intermediate2641997diplatinum;DFT platinum crystal dinuclear;electronic organoplatinum mol bridged dinuclear;electrochem bipyrimidine oxidn structure Dinuclear organoplatinum compds. RnPt(bpym)PtRn (R = Me, n = 2, 4; R = mesityl, n = 2; bpym = 2,2'-bipyrimidine) were prepd. and characterized. The neutral compds. and their neighboring oxidn. states were studied using cyclic voltammetry, 1H NMR or EPR spectroscopy and UV-Vis spectroelectrochem. Oxidn. state assignments based on these data could be made for the following compds.: R2PtII(bpym)PtIIR2, [R2PtII(bpym-I)PtIIR2]·-, [R2PtII(bpym-II)PtIIR2]2-, [Mes2PtIII(bpym)PtIIIMes2]2+, Me4PtIV(bpym)PtIVMe4, [Me4PtIV(bpym-I)PtIVMe4]·-. The two-electron oxidn. of Mes2Pt(bpym)PtMes2, i.e. the absence of a stable Pt(III)/Pt(II) mixed-valent state, confirms that the highest-lying occupied metal orbitals (dz2) do not communicate via the \textgreek{p} system of the bridging ligand. A crystal structure anal. of photoreactive Me4PtIV(bpym)PtIVMe4 was obtained: space group Pbca, a = 12.830(2) {\AA}, b = 11.502(2) {\AA}, c = 12.877(2) {\AA}, V = 1900.3(5) {\AA}3, Z = 4. The structural refinement revealed elongated axial Pt-Me bonds of about 2.13 {\AA}. The structural features could be well reproduced by a DFT calcn. of H4PtIV(bpym)PtIVH4 which also confirmed the \textgreek{s} character of the HOMO. Of the ligand-reduced systems, the Pt(II) species exhibits a higher degree of g anisotropy than the Pt(IV) species. Low-lying excited states of the species generated were assigned through information from vibrational structuring, solvatochromic behavior and from (spectro)electrochem. results. [on SciFinder(R)]