Single-crystal electron paramagnetic resonance study of a trigonal vanadium tris(dithiolate) complex

The Electronic Structure and Spectroscopy of Metallo‐Dithiolene Complexes

“…However, the results of the single-crystal study allowed for the unambiguous determination of the sign for the principle components of the hyperfine tensor, yielding A k ¼ 10 G and A ? ¼ À100 G (Table XV) (408). Note that hAi is now À63.3 G, in agreement with the results of Maki except for the sign of hAi, which was not determined in their frozen glass study.…”

“…However, only the former researchers made concrete attempts to understand the key electronic structure factors that stabilize the TP geometry over the more common octahedral arrangement. Furthermore, the MO description of Gray and co-workers (280,406) has met with more general acceptance due to its ability to explain the electronic origin of the EPR derived spin-Hamiltonian parameters (g i and A i ) for numerous TP metallo-tris(dithiolenes) (387,388,408,409), as well as their effective magnetic moments and the salient features of their electronic absorption spectra (280,406).…”

“…Slightly different versions of the McGarvey equations were used by Stiefel and co-workers (408) in the analysis of the hyperfine coupling and g values, and these are given below:…”

Long Coherence Times in Nuclear Spin-Free Vanadyl Qubits

“…This causes spin-containing solvent nuclei to occupy different positions relative to the vanadium center in the two molecule typesan important consideration as environmental nuclear spins are frequently a main contributor to decoherence. ,,, The two configurations of the metal ion also alter the strength of the molecule’s vibrational coupling with the surrounding solvent molecules, which can affect T 1 . The second dramatic change is in the orbital containing the unpaired electron; in vanadyl complexes it is predominately d x 2 – y 2 in character, whereas in VS 6 complexes the orbital is predominately d z 2 in character. − This change modifies the extent of the electron delocalization from the metal center, potentially increasing interactions of the unpaired electron with the local environment, and therefore affecting decoherence and spin–lattice relaxation . In the expansive EPR literature on both vanadyl and VS 6 complexes, ,− there is a sole, recent investigation on the effect of substituting a vanadyl complex for the analogous VS 6 complex on T 2 and T 1 .…”

“…The second dramatic change is in the orbital containing the unpaired electron; in vanadyl complexes it is predominately d x 2 – y 2 in character, whereas in VS 6 complexes the orbital is predominately d z 2 in character. − This change modifies the extent of the electron delocalization from the metal center, potentially increasing interactions of the unpaired electron with the local environment, and therefore affecting decoherence and spin–lattice relaxation . In the expansive EPR literature on both vanadyl and VS 6 complexes, ,− there is a sole, recent investigation on the effect of substituting a vanadyl complex for the analogous VS 6 complex on T 2 and T 1 . However, the scope of this study was limited to the examination of a single pair of complexes in the solid state and at relatively high concentrations.…”