The copper(II) complexes di-mu-bromo-bis{[2,6-bis(pyrazol-1-yl)pyridine]perchloratocopper(II)} and [2,6-bis(pyrazol-1-yl)pyridine]dibromocopper(II).

The two title compounds, di-mu-bromo-bis{[2,6-bis(pyrazol-1-yl-kappaN(2))pyridine-kappaN](perchlorato-kappaO)copper(II)}, [Cu(2)Br(2)(ClO(4))(2)(C(11)H(9)N(5))(2)], (I), and [2,6-bis(pyrazol-1-yl)pyridine]dibromocopper(II), [CuBr(2)(C(11)H(9)N(5))], (II), were synthesized by only slight modifications of the same reaction; compound (II) was formed by adding one molar equivalent of pyrazole (C(3)N(2)H(4)) to the reaction mixture of (I). Compound (I) is a bromo-bridged dinuclear copper(II) compound stabilized by weak interactions with the perchlorate anions (ClO(4)(-)), while (II) is a related mononuclear species, which has a distorted square-pyramidal geometry.