On the nature of the dimethylphosphinomethanide ligand in organometallic chemistry

The purpose of this work was to examine the behavior of the dimethylphosphinomethanide ligand in Group IV organometallic chemistry. The potential LX interaction between the phosphorous atom and the metal center was investigated. The ligand was examined for potential use in metallocene-based Ziegler-Natta catalysis of olefinic monomers. The complexes were analyzed by multinuclear NMR and were tested for reactivity toward propylene polymerization. The Lewis acid complex, tris(pentafluorophenyl)borane, was utilized in the attempted generation of a Ziegler-Natta active catalyst. The Lewis acid was expected to remove the dimethylphosphinomethanide ligand after the formation of a dative bond between the phosphorous atom of the metallocene complex and the boron atom of the Lewis acid. The data supports the formation of a phosphorous-boron dative bond. However, the data do not support the complete abstraction of the dimethylphosphinomethanide ligand. The data do not confirm the metallocene-Lewis acid complex to be active towards propylene.