Nuclear quadrupole resonance studies of chelated antimony complexes. Part 2. The crystal structure and the35Cl and121,123Sb resonance frequencies of tetrachloro(acetylacetonato)antimony(V) and related compounds

Abstract

35 Cl and 121,123Sb nuclear quadrupole resonance (n.q.r.) spectra of tetrachloro (acetylacetonato)antimony(v), (1), and ten related compounds have been observed and measured in the range 77–300 K. The crystal structures of (1) and of tetrachloro(benzoylbenzophenato)antimony (5) are also reported. The n.q.r. spectrum of the latter compound indicates the occurrence of a second-order phase-change in the neighbourhood of 135 K; this is confirmed by thermal analysis. Comparison of the crystal structure and n.q.r. spectrum of (1) indicates that a similar phase-change takes place here below 77 K. The distinction between the 35Cl resonance frequencies of the axial and equatorial chlorine atoms of these compounds, already suggested in Part 1, is confirmed.