A new platform for NCN dimethylamino pincer complexes: Synthesis and structural studies

The reaction of 2,6-(2-{Me2NCH2}C6H4)2C6H3I (2) with Pd2(dba)3 produced the NCN diamine pincer complex [2,6-(2-Me2{NCH2}C6H4)2C6H3PdI] (3) by an oxidative addition route. The structural analysis of ligand precursor 2 revealed a syn-conformation in the solid state. Single crystal X-ray analysis of complex 3 revealed a conventional square planar geometry about the palladium center and a global C2 symmetric structure. Variable temperature and concentration NMR spectroscopic studies of complex 3 suggest an equilibrium between 3 and the dinuclear species [{2,6-(2-{Me2NCH2}C6H4)2C6H3Pd}2μ2-I]I in CDCl3 solution. An unusual carbonate complex [{2,6-(2-{Me2NCH2}C6H4)2C6H3Pd}3μ3-CO3]I3 (4) was also structurally characterized as a minor product during synthesis of 3.