The chlorine-35 and antimony-121 and -123 nuclear quadrupole resonance spectra of five-membered ring chelate derivatives of antimony pentachloride

Abstract

The ³⁵Cl and ^121,123Sb quadrupole resonance spectra of several five-membered ring chelate derivatives of antimony pentachloride are reported. Four of these are of known structure: the singly chelated derivatives of tropolone, N-methyloxamide, and NN′-dimethyloxadiamide, and the doubly chelated derivative of oxalic acid. The doubly chelated derivative of NN′-dimethyloxadiamide, of unknown crystal structure, has also been measured. The ³⁵Cl resonance frequencies of the axial and equatorial chlorine atoms are quite distinct and, for the tropolone complex, imply a 10% difference between the ionicity of the axial and equatorial groups, and are affected to a different extent by the nature of the chelate group. The large value of the ¹²¹Sb asymmetry parameter of the oxalate complex is satisfactorily explained by the observed small angular deformations of the geometry from that of a regular octahedron.