Spectroscopic evidence for hemilabile behavior in a β-ketophosphonate complex of molybdenum(VI)

Article abstract of DOI:10.1080/00945719809351664

The β-ketophosphonate complexes dichlorodioxo(diethyl(2-phenyl-2-oxoethyl)phosphonate)molybdenum(VI) (5a) and dichlorodioxo(triethylphosphonoacetate)molybdenum (VI) (5b) have been synthesized in 61-80% yield and characterized by NMR and IR spectroscopies. The crystal structure of (5a) (orthorhombic, 2₁2₁2₁, a = 8.0909 (5) A, b = 14.1432 (5) A, c = 14.9749 (8) A, Z = 4) shows that the β-ketophosphonate ligand is coordinated to the molybdenum atom in a bidentate binding mode. In solution, compound (5a) displays hemilabile behavior as revealed by an IR spectrum recorded in CH₃CN. Reaction of (5a) with diphenylsulfoxide (DPSO) in CH₂Cl₂ results in complete displacement of the β-ketophosphonate ligand and formation of dichlorodioxobis(diphenylsulfoxide)-molybdenum(VI) (8) in 96% yield.