Alternating Cu(II) chains with bridging pyrazine, oxy- and halo-ligands.

AbstractTwo new Cu(II)-based structures containing alternating chains and their magnetic properties are reported. Reaction of CuBr2 and 2-aminopyridine in methanol yielded [(2-aminopyridine)μ-Br(μ-OMe)Cu]n (<bold>1</bold>) which crystallizes in the triclinic space group <italic>P</italic>-1. Cu(II) ions are linked alternately by bibromide and bi-methoxide bridges into chains parallel to the <italic>a</italic>-axis. Reaction of copper perchlorate hexahydrate with 4-pyridone and pyrazine in methanol yielded [(μ-pz)(μ-κ-O-4-pyridone)2(μ-OH)2Cu2]n(ClO4)2n (<bold>2</bold>). The Cu(II) ions are alternately linked by bihydroxide and bi-κ-O-4-pyridone species parallel to the <italic>a</italic>-axis. Those chains are further linked by bridging pyrazine molecules ∼ parallel to the <italic>b</italic>-axis, with the pyrazine molecules and bi-hydroxide bridges alternating. The net effect is a rectangular lattice where each side of the rectangle is an alternating chain. The layers are separated by perchlorate ions. Both compounds are diamagnetic at room temperature. [ABSTRACT FROM AUTHOR]