An electron transfer series of octahedral chromium complexes containing a redox non-innocent α-diimine ligand

Abstract

An electron-transfer series of octahedral α-diimine complexes [(^HL^Cy)₃Cr]ⁿ⁺(BARF)_n (n = 2, 1, 0) has been synthesized and crystallographically characterized. Cyclic voltammetry indicated additional formation of [(^HL^Cy)₃Cr]³⁺. The molecular structures suggested that all redox processes were ligand-based. Magnetic moments were consistent with spin ground states of S = 0 for [^HL^Cy₃Cr]⁰, S = 1/2 for [^HL^Cy₃Cr]⁺¹, and S = 1 for [^HL^Cy₃Cr]⁺². The experimental data is consistent with chromium maintaining the +III oxidation state throughout, while being coordinated by varying numbers of neutral diimines (^HL^Cy) and diimine radical anions (^HL^Cy˙⁻).