Copper(Ⅱ) fumarate complex with 2,2'-bipyridine, [Cu~2(fum)(bipy)~4] [fum]·12H~2O, has been synthesized and characterized by elemental analyses, IR, electronic reflectance spectra and magnetic studies. The single crystal X-ray diffraction study shows that the complex is triclinic, with space group P1(#2), a=1.0697(2) nm, b=1.2820(2) nm, c=1.0470(3) nm, α=101.88(2)°, β=101.93(2)°, γ=79.41(1)°, Z=1, and R=0.033. Two copper(Ⅱ) atoms are bridged by a fumarate group, with each copper(Ⅱ) atom coordinated with two 2,2'-bipyridine molecules, forming a distorted trigonal bipyramidal configuration. The alternating temperature magnetic susceptibility study suggest that there exist weak ferromagnetic interaction between two copper(Ⅱ) atoms.

Key words: COPPER COMPLEX, BUTENEDIOIC ACID P, BIPYRIDINE P, ELEMENTAL ANALYSIS, INFRARED SPECTROPHOTOMETRY, CRYSTAL STRUCTURE