anti-syn and anti-anti coordination of the bridging CO32- group in [Cu2(Phen)4(μ-CO3)]B10H10 binuclear complexes: Synthesis, structure, and magnetic properties

A redox reaction that occurs in the [Cu2B10H10]/Phen system in CH3CN/DMSO and CH3CN/DMF in air yields a Cu(II) binuclear complex, [(Phen)(2)Cu(CO3)Cu(Phen)(2)](2+). The [Cu-2(Phen)(4)(mu-CO3)]B10H10 center dot 2.5DMSO center dot 2H(2)O (I) and [Cu-2(Phen)(4)(mu-CO3)]B10H10 center dot 4DMF (II) compounds have been isolated and studied by X-ray crystallography at 150 K and EPR at 295 K. Their magnetic properties have been studied in the range 300-2 K. In the cations of both compounds, the bridging CO (3) (2-) group is bidentately coordinated to two Cu atoms. The cations in I and II have different spatial orientations of the Cu-O bonds: anti-syn and anti-anti, respectively. Compound I has weak magnetic interactions caused by a short CuaEuro broken vertical bar Cu distance (4.441 ) in the dimer. No exchange coupling is observed in II.