Novel and facile procedure for the synthesis of Ni(II) and Pd(II) PSCOP pincer complexes: evaluation of their catalytic activity on C-S, C-Se and C-C cross coupling reactions

Abstract

A new and facile procedure for the synthesis of non-symmetric phosphinito-thiophosphinito PSCOP pincer complexes based on Ni(II) and Pd(II) was developed. The synthesis of the complexes was carried out in a single step, starting from 3,3-dihydroxydiphenyldisulfide. The Ni(II) complexes were tested as catalysts in C-S and C-Se coupling reactions, being the t Bu derivative 3-Ni the one exhibiting the best performance in both transformations. In this case, the sterics of the substrates was studied, showing that higher steric hindrance leads to lower yields. Analogously, the Pd(II) complexes were used as catalyst in Suzuki-Miyaura couplings of para-substituted bromobenzenes and phenyl boronic acid, being the analogous t Bu derivative complex 3-Pd the best catalysts for this process, exhibiting tolerance to a wide range of functional groups.