Redox Conversion of Cobalt(II)‐Diselenide to Cobalt(III)‐Selenolate Compounds: Comparison with Their Sulfur Analogs

The synthesis of the selenium-based ligand L1SeSeL1 (2,2’-diselanediylbis(N,N-bis(pyridin-2-ylmethyl)ethan-1-amine) is described along with its reactivity cobalt(II) salts. cobalt(II)-diselenide complex [Co2(L1SeSeL1)Cl4] was obtained in good yield, and spectroscopic properties closely resemble that sulfur analog. Reaction Co(II) thiocyanate results formation cobalt(III) compound [Co(L1Se)(NCS)2], similar to reaction L1SSL1. redox-conversion reactions from Co(II)-diselenide [Co(L1SeSeL1)Cl4] using external triggers such as removal halide ions or addition strong-field 8-quinolinolate resulted yields Co(III)-selenolate complexes [Co(L1Se)(MeCN)2](SbF6)2 [Co(L1Se)(quin)]Cl. Our computational studies show ligand-field splitting energy selenium compounds smaller than their analogs, indicating cobalt(III)-selenolate may be more arduous for related compounds.