Mu-peroxo-bis[trans-chloro(1,4,8,11-tetraazacyclotetradecane)cobalt(III)] bis(tetraphenylborate) diacetone solvate

The title complex, [Co(2)Cl(2)(mu-O(2))(cyclam)(2)](C(24)H(20)B)(2).2Me(2)CO, was obtained when [Co(cyclam)Cl(2)](BPh(4))(2) was crystallized from acetone in air; cyclam is 1,4,8,11-tetraazacyclotetradecane, C(10)H(24)N(4). The peroxo O-O moiety straddles a crystallographic centre of inversion (the two octahedral Co atoms are symmetrically bridged by the O(2) moiety), hence only half of the complex cation is in the asymmetric unit. A comparison of the O-O [1.483 (3) A], Co-Cl [2.2647 (8) A] and Co-O [1.894 (2) A] bond lengths with similar bonds in previously determined structures indicates the oxidation of Co(II) to Co(III) during the crystallization process. In the crystal lattice, cation dimers are encapsulated by six [BPh(4)](-) anions, with C-H...pi hydrogen bonds between the cyclam methylene groups and the phenyl rings of the anion.