Reactivity of boron cluster anions [B10H10]2−, [B10Cl10]2− and [B12H12]2− in cobalt(II)/cobalt(III) complexation with 1,10-phenanthroline

•Mono- and binuclear cobalt(II) complexes with boron cluster anions [B10H10]2−, [B10Cl10]2− and [B12H12]2− were synthesized.•The first cobalt(III) complex with low reactive [B12H12]2− was obtained.•The crystal structures were determined by X-ray diffraction.

Reactivity of three boron cluster anions [B10H10]2−, [B10Cl10]2− and [B12H12]2− with cobalt(II) chloride and 1,10-phenanthroline was studied in acetonitrile and DMF, in the presence of an oxidizing agent CeIV and without it. It was found that the nature of the boron cluster, solvent used, reagents ratio and cobalt complexation chemistry affect reaction path. Cobalt(II) complexes [Co(phen)3][An] (An = [B10H10]2−, [B10Cl10]2− and [B12H12]2−), [Co(phen)2(μ-Cl)2Co(phen)2][B10Cl10] as well as the first cobalt(III) complex with boron cluster [Co(phen)3][B12H12]NO3 were formed and characterized by IR and UV–Vis spectroscopy as well as X-ray diffraction. Selective preparation of known substituted derivative 1,2-[B10H8(phen)] was carried out. In addition, cobalt(II) and cobalt(III) complexes [Co(phen)3]Cl2·7.5H2O and [Co(phen)2Cl2]NO3·H2O were structurally characterized.

Graphical abstractPhen-containing mononuclear hexacoordinate cobalt(II) complexes [Co(phen)3][BnXn] (n = 10, 12; X = H, Cl) as well as a binuclear cobalt(II) complex [Co2(phen)4Cl2][B10Cl10] were synthesized. For low reactive [B12H12]2−, the first cobalt(III) complex was obtained.Figure optionsDownload full-size imageDownload as PowerPoint slide