Synthesis and characterization of technetium complexes with phosphoruscontaining ligands. The homoleptic trimethylphosphite, dimethylmethylphosphonite and methyldiethylphosphinite technetium(I) cations

Abstract

Technetium(I) complexes of trimethylphosphite (tmp), dimethylmethylphosphonite (dmmp) and methyldiethylphosphinite (mdep) have been synthesized through direct interaction of the ligand with sodium pertechnetate. The homoeleptic, hexakis (ligand), cationic complexes can be isolated as tetraphenylborate salts. Characterization using multinuclear NMR of 99Tc (−422 and −248 ppm versus TcO 4 − for the tmp and dmmp complexes, respectively) and 31P (158.5 and 248 ppm versus 85% H 3PO 4 for the tmp and dmmp complexes, respectively) gives chemical shift values which compare favorably with previous data on Tc-phosphine and transition-metal-phosphite complexes. Mass spectra (fast atom bombardment and plasma desorption) of the tmp and dmmp complexes exhibit the expected parent peaks and show series of peaks attributed to stepwise loss of ligand molecules or possible decompositon products. X-ray photoelectron spectra of the tmp and dmmp complexes are consistent with formulation as the Tc(I) oxidation state when referenced to well-characterized complexes in known oxidation states.