ESR and Magnetic Susceptibility Studies on High-Spin Tetrahedral Cobalt(II)–Thiolate Complexes: An Approach to Rubredoxin-Type Active Sites

Magnetic susceptibility and ESR studies on high-spin (S=3⁄2) tetrahedral cobalt(II)–thiolate complexes were performed for A2[Co(SPh)4]; A=Me4N (1a), Et4N (1b), Ph4P (1c) and (Et4N)2[Co(SR)4]; R=C6H4-p-Me (2), C6H4-p-Cl (3), C6F5 (4). It was found that the magnitude of zero-field splitting and the anisotropy of g-factor are exceptionally large for 1c as D≈−100 cm−1, E≈0, gx≈gy