Naphthyl and biphenyl para-substituted POCOP-Ni(II) pincer complexes as efficient catalysts in C-S cross-coupling reactions

A series of six novel para-poly-aromatic acyl-functionalized nickel POCOP-pincer complexes, [NiCl{C6H2-4-Y-2,6-(OPR2)(2)}] (Y = [1,1 '-biphenyl]-4-carboxylate, 2-naphthoate, R = Pr-i, Bu-t, Ph), have been synthesized in a straightforward manner in high yields. All new complexes have been fully characterized by standard techniques and three of them unequivocally confirmed by single crystal X-ray diffraction analysis. The catalytic activity of the complexes was examined in C-S cross coupling reactions of iodobenzene with both aryl and alkyl thiols showing high conversions with low catalyst loadings.