An electron spin resonance study of dimeric titanium(III) complexes

Abstract

The e.s.r. spectra of dimethylformamide solutions of the titanium(III) complexes of mandelic, malic, citric, cyclopentane-1,2,3,4-tetracarboxylic, 5-sulphosalicylic, 5-chlorosalicyclic, p-aminosalicyclic, and phthalic acids, salicylamide and 8-hydroxyquinoline have been observed. The results provide evidence for the formation of dimeric species from the observation of spectra at 77 K due to ΔM= 1 transition in the g ca. 2 region and in most cases the observation of low-field components of the spectra at g ca. 4. The solution of an appropriate spin Hamiltonian which includes the magnetic dipole–dipole interaction between the titanium ions makes possible the computer simulation of the line shapes of the spectra associated with the dimeric species. By this procedure the magnetic parameters of the titanium(III) pairs have been evaluated, the parameter of chief interest being the distance between the metal ions in the dimeric complexes. This information has been used to suggest possible structures of these dimers.