Synthesis and characterization of two stable paramagnetic octahedral chromium(IV) complexes with dianionic tridentate SNO donor ligands and of a chromium(III) complex with a ONO donor ligand

Two novel paramagnetic octahedral chromium(IV) complexes with dianionic tridentate SNO donor ligands, [Cr(abtsal)2] and [Cr(4-PhTSCsal)2]·H2O having magnetic moments 2.98 and 2.83BM, exhibit X-band powder EPR spectra which show the allowed transition ΔMs=±1 as well as the “forbidden” half-field transition ΔMs=±2. The LNT frozen glass EPR spectrum of [Cr(abtsal)2] shows the presence of zero-field split rhombic symmetry character, and results in the parameters g≅2.0, D=740G, and E=260G. A related dianionic tridentate ONO donor ligand stabilized a paramagnetic octahedral chromium(III) complex that has been structurally characterized by X-ray crystallography.