Syntheses, characterization, crystal structure and magnetic properties of copper(II) alpha,beta-unsaturated carboxylate complexes with acetamide

Two copper(II) alpha,beta,-unsaturated carboxylate complexes with acetamide , Cu-2(CH2=CHCOO)(4)(C2H5NO)(2)(1) and Cu-2[CH2=C(CH3)COO](4)(C2H5NO)(2)(2) , have been synthesized and characterized by elemental analyses, IR, ESR, e lectronic spectra and magnetic studies. The single crystal X-ray diffractio n study of two complexes shows that complex 1 crystallizes in the monolinic space group with P2(1)/c, a = 1.5333(5) nm, b = 1.0044(3) nm, c = 1.6184(7 ) nm, beta = 115.28(3)degrees, Z = 4, and R = 0.0701, while complex 2 is tr iclinic, with space group P (1) over bar, a = 0.93327(11) nm, b = 1.12484(1 1) nm, c = 1.3740(6) nn, alpha = 94.90(2)degrees, beta = 108.409(14)degrees , gamma = 110.556(5)degrees, Z = 2 and R = 0.0351. Two copper(II) atoms are bridged by four alpha,beta-unsaturated carboxylate groups, with each coppe r(II) atom coordinated with an acetamide molecule in the axial position, fo rming a distorted square pyramidal configuration. The symmetric center is b etween the two copper(II) atoms. The Cu-Cu bond distance is 0.26302(13) nm for the complex 1 and 0.26383(4) nm for the complex 2. The Cu-Cu distance a nd magnetic studies suggest that there exist antiferromagnetic interaction between two copper(II) atoms.