Abstract
Mononuclear chromium(III) complexes of formula mer-[CrIIICl3(pz*H)3] (pz*H = pyrazole (pzH), and substituted pyrazoles: 3-Me-pzH, 4-Me-pzH, 4-Cl-pzH, 4-Br-pzH, 4-I-pzH) and trans-[CrIIICl2(pzH)4]Cl were synthesized from reactions of CrCl3 hydrate and pyrazole ligands and crystallographically characterized. The fluxional behavior of the complexes, attributed to pyrazole tautomerization, was probed by variable temperature 1H NMR spectra in the −50 °C to +23 °C range and activation parameters were derived. Q-band EPR were recorded and analyzed for mer-[CrIIICl3(pz*H)3] (R = H, Me, Cl) showing satellite features corresponding to weak zero-field splitting (zfs).
