Abstract:
Novel chromium and tungsten mono- and multiethoxycarbene
complexes were synthesized from tris(4-
bromophenyl)amine and tri(2-furyl)phosphine substrates. A
comparative study between the amine and phosphine
multicarbene complexes revealed small differences between
the respective compounds. In solution, an equilibrium
situation was observed between the mono- and bis-carbene
complexes of tri(2-furyl)phosphine. The monocarbene amine
ligand differs from the analogous phosphine ligand in the way
the heteroatom lone pair electrons are able to interact with the
carbene functionality. Unlike for the phosphine, the greater electron delocalization of the amine affected the coordination ability
of the ligand when reacted with [Pt(COD)Cl2]. These properties of the monocarbene-carrying ligands were confirmed and
supported by solid state structural studies, spectroscopic data, and density functional theory (DFT) calculations.
