Preparation and characterization of carbonyltetrakis (trimethylphosphine) rhenium (I) chloride.

Abstract

The current work focused on the preparation of organometallic derivatives of rhenium metal carbonyl complexes. The ligand derivatives were prepared as precursors to the metal carbonyl complex target species. The ligands that were coordinated to the metal carbonyl moeity are triphenylphosphine and trimethylphosphine. These ligands were prepared by a microscale Grignard synthesis beginning from readily available starting reagents. The purity and characterization of these ligands were performed by FT-IR spectroscopy. The derivatives were coordinated to the metal carbonyl moeities by allowing the two species to react in refluxing bis-(2-methoxyethyl)ether and triethanolamine solvents. The reactions required a minimum of six hours, on the microscale, in order to ensure completion. The former solvent was chosen for coordination of triphenylphosphine; and the latter for coordination of trimethylphosphine. The resulting rhenium carbonyl products were characterized by FT-IR spectroscopy. Carbonyl stretching frequencies for many compounds containing strongly k-accepting ligands give characteristic absorption bands in the 2000 cm-region. These stretching frequencies often yield real Cotton-Kraihanzel force constants if the two physically different cis-CO-CO interactions are differentiated [1].