Electron Spin Resonance of Titanium (III) Acetylacetonate

Abstract

The ESR spectra of titanium (III) acetylacetonate present in small amounts in single crystals of aluminum (III) acetylacetonate has been investigated both at room temperature and at liquid‐nitrogen temperature. The spectra arising from the isotopes with no nuclear spin gave the following: g‖ = 2.000±0.002; g_‖ = 1.921±0.001. The linewidths at room temperature were about 70 G, but narrowed down to less than 10 G at liquid‐nitrogen temperatures. At liquid‐nitrogen temperatures, the hyperfine spectrum due to isotopes Ti⁴⁷ and Ti⁴⁹ was observed and is shown to confirm previous assignments of nuclear spins. The hyperfine components of the spin Hamiltonian were found to be: A = 6.3±3.0×10^—4 cm^—1; B = 17.5±0.5×10^—4 cm^—1. It is shown that these results are consistent with an A₁ ground state and with the E_a state, being from 2000 to 4000 cm^—1 above the ground state. Further, it is shown that the results suggest a considerable degree of covalent interaction involving π electrons of the ligands.