X-Ray and NMR Study of the Structural Features of SCS-Pincer Metal Complexes of the Group 10 Triad

Abstract

SCS-pincer metal complexes [MX(SCS)] (SCS = [2,6-(RSCH 2 ) 2 C 6 H 3 ] −; R = Ph: Ph SCS; R = Me: Me SCS; M = Pd, Pt, Ni) have been synthesized via mild and tolerant oxidative addition procedures. The complexes have been characterized by 1 H and 13 C NMR spectroscopy and X-ray crystal structure determination. Interestingly, the crystal structures of [NiBr( Me SCS)] 4, [PdBr( Me SCS)] 5, [PtBr( Me SCS)] 6, and [PtBr( Ph SCS)] 8 each have a unit cell with a unique set of independent [MBr( R SCS)] molecules; each of these structures has a different conformation of the five-membered ortho -chelate ring (including the configuration of the coordinated S-center) in the solid state. The temperature-dependent 1 H NMR resonance patterns of these complexes in solution were related to structural features encountered in the solid state and allowed us to assign all dynamic processes ( rac/meso isomerizations) that occurred in solution.