Intramolecular electron transfer in the mixed-valence [Co(3,5-DTBCat)(3,5-DTBSQ)(bpy)] complex: Beyond valence tautomerism

The series of complexes [Co(Q)2(bpy)]n (n = −1, 0, +1) that can be derived by partial reduction or oxidation of complex 1, ls-Co(III) has been synthesized and studied. The results support the theoretical calculations which pointed to an intervalence transfer (IT) from the Cat2− to the SQ− ligand rather than a LMCT transition as the origin for the low-energy band transition centered at 2500 nm observed for 1, ls-Co(III).