Trichloro- and triisopropoxy-niobium(V) and tantalum(V) bis -( O , O ′-alkylene dithiophosphates): synthesis and characterization

Abstract

Trichloro- and triisopropoxy-niobium(V) and tantalum(V) alkylene dithiophosphates, (M = Nb(V) or Ta(V); G =–CHMeCHMe–,–CMe2CMe2–,–CH2CMe2CH2–,–CH2CEt2CH2–or–CMe2CH2CHMe–and X = Cl or OPri) have been synthesized by reaction of metal(V) chloride, MCl5, or triisopropoxymetal(V) dichloride, (PriO)3MCl2, with the sodium salts of O,O′-alkylene dithiophosphoric acids, in 1 : 2 molar ratio in THF under anhydrous conditions. These pink-purple or light-yellow compounds are viscous, semi-solid or solid, hydrolyzable and soluble in common organic solvents. These compounds have been characterized by elemental analyses, molecular weight determinations and spectral studies like IR and heteronuclear NMR (1H, 13C and 31P), which indicated a bidentate mode of chelation of dithio ligands, leading to a pentagonal bipyramidal geometry around the niobium(V) or tantalum(V) centers.