Homoleptische Carbenkomplexe, IV. Tetrakis(N-alkylimidazolin-2-yliden)palladium and -platin/Homoleptic Carbene Complexes, IV. Tetrakis(N-alkylimidazolin-2-ylidene)palladium and -platinum

Abstract

Homoleptic complexes of palladium and platinum containing carbenoid imidazole ligands (1, 12-19 ) have been synthesized either directly from C2-lithiated N-methyl-imidazole and Pdl 2 or, indirectly (and more efficiently), from isocyanides and 2-am inoacetaldehyde diethylacetale in the presence of Pdl 2 , Ptl 2 or K 2 PtCl 4 via the respective “ open chain” diaminocarbenes 2-11. Selected IR , NMR ( 1 H , 13 C), and pos-FAB mass spectrometric data of the new compounds are reported. The X-ray structure analysis of tetrakis(N -methylimidazolin-2-ylidene)palladium-diiodide (lb ) reveals a geometry of the heterocyclic ligands which deviates considerably from the one expected for extensive 6π-electron delocalization across the ring.