Synthesis, Structure, and Asymmetrization of Tri-p-tolylantimony Derivatives of Alpha-Substituted Acetic, Methacrylic, and Crotonic Acids

Abstract

The aim of this work was to synthesize tri-p-tolylantimony dicarboxylates containing substituted acetic, methacrylic, and crotonic acids, to study their structure using IR, NMR, and X-ray methods, and to explore the possibility of obtaining asymmetric dicarboxylates with one non-polymerizing carboxylate fragment and one polymerizable fragment. The reaction of tri-p-tolylantimony with H₂O₂ or t-BuOOH and the corresponding carboxylic acids resulted in the synthesis of derivatives of tri-p-tolylantimony with yields of 57–90%, including saturated dicarboxylates (p-Tol₃Sb(O₂CCH₃)₂, p-Tol₃Sb(O₂CCH₂Cl)₂, p-Tol₃Sb(O₂CCHCl₂)₂, p-Tol₃Sb(O₂CCCl₃)₂, p-Tol₃Sb(O₂CCH₂CN)₂) and unsaturated dicarboxylates (p-Tol₃Sb(O₂CC(CH₃)=CH₂)₂, p-Tol₃Sb(O₂CCH=CHCH₃)₂). The structures of the obtained compounds were studied using modern physicochemical methods, including NMR and X-ray crystallography with the structural parameter τ, as well as IR spectroscopy with a comparison of the differences in the wavenumbers of the valence vibrations ν_as(COO) and ν_s(COO). For the first time, the possibility of synthesizing an asymmetric tri-p-tolylantimony dicarboxylate via a disproportionation reaction was explored, and the equilibrium constant of this reaction was calculated.