Grøndahl, L.,Josephsen, J., Bruun, R. M. and Larsen, S.,  Acta Chem.Scand.  53(1999)1069-1077

Syntheses and characterisation by ¹H NMR and IR of the platinum(II) complexes [PtI₂(Ph₂C=NH)₂], [PtCl₂(Ph₂C=NH)₂], [PtCl(Ph(Ph-H)C=NH)(NH₂CH₂CH₂NH₂)] and trans-(N,N)-[PtCl(Ph(Ph-H)C=NH)(Ph₂C=NH)] are described. Absorption and emission spectra at room temperature for the latter complex are reported. The crystal structure of trans-(N,N)-[PtCl(Ph(Ph-H)C=NH)(Ph₂C=NH)].1/2{(CH₃)₂CO} was determined by X-ray diffraction methods. Space group C2/c, a = 14.318(4) Å, b = 22.854(4) Å. c = 15.212(3) Å and b = 108.42(2)°,using 10 368 reflections in the refinement of 291 parameters gave R = 0.037 and wR2 = 0.074 (for all data). The ligands surround platinum in a planar configuration with bond lengths of Pt-Cl 2.404(1) Å, Pt-N(monodentate imine ligand) 2.004(3) Å, Pt-N(bidentate imine ligand) 1.979(3) Å and Pt-C 1.988(3) Å. The chemical shifts in the 1H NMR spectrum of trans-(N,N)-[PtCl(Ph(Ph-H)C=NH)(Ph₂C=NH)] (in CDCl₃) display variations with concentration of the complex that indicates dimerisation. The dimerisation constant was determined from the change in chemical shift for the NH proton of the ortho-metalated ligand, K = 1.25(4) M^-1 at 300 K. The structure of the dimer in solution is proposed to resemble one of the types of interactions that are encountered between platinum complexes in the solid state.