Synthesis of dialkyl, diaryl and metallacyclic complexes of Ni and Pd containing pyridine, α-diimines and other nitrogen ligands: Crystal structures of the complexes cis-NiR 2py 2 (R=benzyl, mesityl)

Abstract

The alkylation of NiCl 2py 4 or PdCl 2py 2 with organomagnesium or organolithium reagents affords dialkyl complexes cis-MR 2py 2 (R=Me, CH 2SiMe 3, CH 2Ph, CH 2CMe 2Ph, 2,4,6-C 6H 2Me 3). The methyl and trimethylsilyl derivatives undergo ligand exchange reactions with chelating nitrogen ligands (α-diimines or 2-imidoylpyridines), yielding the corresponding dialkyl derivatives in good to excellent yields. A catalytic amount of PMe 3 induces the transformation of the nickel complex Ni(CH 2CMe 2Ph) 2py 2 into the metallacyclic derivative NiCH 2 CMe 2-o- C 6 H 4( py) 2 .The latter, and the related palladacycle Pd( CH 2 CMe 2-o- C 6 H 4) ( cod) , also undergo facile ligand exchange reactions.