Coordination of 3,3'-Bipyridazine With Bivalent Copper, Palladium and Platinum

Abstract

Bis ( ligand ) complexes of the diimine 3,3′-bipyridazine (L) with bivalent copper, palladium and platinum are described. Green and violet forms of [CuL₂] [BF₄]₂ were obtained, and the electronic and vibrational spectra suggest coordinated fluoroborate groups in the violet species. In the green complex a tetragonal structure is indicated. Coordination of perchlorate in [PdL₂] [ClO₄]₂ is also indicated but not in [PtL₂] [ClO₄]₂. Structure determination of the latter complex reveals a strictly planar PtN₄ moiety, and in fact the whole complex cation is approximately planar. Reduced interligand repulsions, compared to those operative in bis ( ligand ) complexes of 2,2?-bipyridine, are believed to allow the essentially planar conformation. The structure of [PtL₂] [ClO₄]₂ was determined at 295 K by single-crystal X-ray diffraction methods, and was refined to a residual of 0.033 for 1942 'observed' independent reflections. Crystal data: [PtL₂][ClO₄]₂ monoclinic, space group P2₁/c (C^5/2h, No. 14), a 7.919(2), b 13.086(3), c 10.313(3)Ǻ, β 107.16(2)°.