{[P(o-tolyl)3]Br}2[Cu2Br6](Br2)--an ionic compound containing molecular bromine

Dark green cuboid-shaped crystals of the composition {P(o-tolyl) 3]Br} 2Cu 2Br 6](Br 2) are obtained by the reaction of P(o-tolyl) 3 and CuBr 2 with Br 2 in the ionic liquid NMeBu 3]N(Tf) 2]. The bromocuprate crystallizes triclinic space group P1; Z = 1; a = 10.667(2) A; b = 10.695(2) A; c = 11.582(2) A; alpha = 74.42(3) degrees ; beta = 75.64(3) degrees ; and gamma = 85.68(3) degrees ]. The title compound is constituted of {P(o-tolyl) 3]Br} (+) cations and Cu 2Br 6] (2-) anions and contains molecular dibromine d Br-Br = 2.341(1) A]. The latter is verified by thermogravimetry and mass spectrometry.