89463-04-7Relevant academic research and scientific papers
Steric and electronic control of the Arbuzov reaction in transition-metal halides: A 1H and 31P NMR study of the reaction of [CpCo(L L)X]+ complexes (L L = N, P, as chelate ligands; X- = Cl-, Br-, I-, CN-) with P(OCH3)3
Landon, Shayne J.,Brill, Thomas B.
, p. 1266 - 1271 (2008/10/08)
Synthesis of a series of complexes, [CpCo(L L)X]+ (L L = N, P, As chelate ligands; X- = Cl-, Br-, I-, CN-), was undertaken with the goal of characterizing the Michaelis-Arbuzov reaction between these complexes and P(OCH3)3. 1H and 31P NMR results provide support for the previously postulated two-step mechanism involving an initial equilibrium reaction [CpCo(L L)X]+ + P(OCH3)3 ? {CpCo(L L)[P(OCH3)3]}2+ + X- followed by alkylation of X- to produce an organometal-phosphonate complex, {CpCo(L L)[P(OCH3)3]}2+ + X- → {CpCo(L L)[P(O)(OCH3)2]}+ + CH3X. Several of the intermediate phosphite dications were synthesized and characterized. They enable the above reactions to be qualitatively separated. The initial reaction was quenched by sterically bulky chelate ligands. The rate of the overall reaction parallels the electron donor power of the attacking nucleophile (CN- > I- > Br- > Cl-) and also depends on the donor atoms of L L (N > P). Chelate dissociation occurs when L L = As. The results for [CpCo(L L)X]+ and other transition metal-halide complexes are discussed in terms of why the Arbuzov reaction takes place in some of these complexes but not with others.
