Ti47andTi49Hyperfine Structure in the Electron Spin Resonance of Titanium (III) Complexes

Abstract

Satellite lines have been resolved in the solution electron spin resonance spectra of two complexes of titanium (III). These lines arise from hyperfine interaction of the unpaired electron with the odd isotopes of titanium, ${\mathrm{Ti}}^{47}$ and ${\mathrm{Ti}}^{49}$. The nuclear spins of the two isotopes are found to be $\frac{5}{2}$ and $\frac{7}{2}$, respectively, in agreement with earlier nuclear induction intensity measurements. The Ti hyperfine constants for the two complexes are almost identical (50.0 Mc/sec). The two complexes studied are a one-to-one complex between titanium (III) and the OC${\mathrm{H}}_{3}^{\ensuremath{-}}$ ion, and the Ti${\mathrm{F}}_{2}^{+}$ ion. The preparation of these complexes is discussed. In the case of the Ti${\mathrm{F}}_{2}^{+}$ ion, an additional hyperfine interaction is observed with the two fluorine nuclei. The splitting constant for the fluorine interaction is 21.1 Mc/sec.The optical spectra of these complexes show large splittings of the $d$-electron levels which are believed to be the result of strong axial perturbations by the coordinating ligands. These splittings lengthen the electron spin lattice relaxation time sufficiently to permit the resolution of the satellite lines.