Synthesis and crystal structures of the first C2-symmetric bis-aldimine NCN–pincer complexes of platinum and palladium

Abstract

( S, S)-2,6-bis[( N-α-methylbenzyl)imino]phenylpalladium bromide was synthesised by oxidative addition of palladium(0) to ( S, S)-1-bromo-2,6-bis[( N-α-methylbenzyl)imino]benzene. In contrast, ( S, S)-2,6-bis[( N-α-methylbenzyl)imino]phenylplatinum chloride was synthesised by direct C–H activation from the reaction of potassium tetrachloroplatinate with ( S, S)-1,3-bis[( N-α-methylbenzyl)imino]benzene. The X-ray crystal structures of both pincer complexes were obtained. Treatment of both complexes with silver hexafluoroanimonate gave effective but not stereoselective catalysts for a Michael reaction between methyl vinyl ketone and methyl 2-cyanopropanoate.