Synthesis and coordination chemistry of thiophenol-based heterodonor ligands containing P,S, As,S and P,SAs donor atoms

Abstract

This review article describes the synthesis and coordination chemistry of three types of thiophenol-based heterodonor ligands containing tertiary phosphine and/or arsine groups in combination with sulfur. Phenylthio(diphenyl)phosphine and -arsine ligands, EPh2(SPh) (E = P, As), incorporate an E–S bond in their structures. Upon reaction with different metal carbonyls, metal-mediated cleavage of the E–S bonds of these ligands has been observed, leading to a variety of sulfur- and phosphorus- or arsenic-containing metallacycles. The structurally isomeric phosphino- and arsinoarylthiols HSC6H4-2-EPh2 (ESH) combine a phosphine or arsine centre with a thiol functionality, which is usually deprotonated on coordination. These compounds have been shown to be very versatile ligands that form stable complexes with a wide range of transition metals. The heterotopic ligand 1-Ph2AsSC6H4-2-PPh2 (P,SAs) not only combines the properties of phenylthio(diphenyl)arsine and 2-diphenylphosphanylbenzenethiol by incorporating all three donor atoms in its structure, but also allows the effect of the PPh2 group in the ortho position on the cleavage of the As–S bond to be studied.