SYNTHESIS AND CHARACTERIZATION OF MONONUCLEAR COMPLEXES CONTAINING 3-ACETYLAMINO-1,2,4-TRIAZOLE (AAT) - X-RAY STRUCTURE OF [CO(AAT)2(H2O)2]BR2

The spectroscopic characteristics of the isostructural compounds [M(aa t)2(H2O)2]X2 (aat=3-acetylamino-1,2,4-triazole; M=Co, Cu, X=Br, Cl; M= Ni, X=Cl) are described. The structure of [Co(aat)2(H2O)2]Br2 has been determined by X-ray diffraction methods. Crystals are monoclinic, spa ce group P2, la with a = 9.686(3), b = 14.433(4), c = 6.169(2) angstro m, beta = 92.84(2)-degrees and Z = 2. The structure was refined to fin al R and R' values of 0.033 and 0.039 for 1066 observed reflections. I n the mononuclear cationic complex, having an imposed crystallographic C(i) symmetry, the cobalt atom is surrounded in a slightly distorted octahedral arrangement by two axial water molecules (Co-Ow=2.108(5) an gstrom) and in the equatorial plane by two oxygen atoms (Co-O(1) = 2.1 00(4) angstrom) and two triazole nitrogen atoms (Co--N(3)=2.063(5) ang strom) from two aat chelating ligands. The complex cations are associa ted in chains, with interposed bromide anions, by hydrogen bonding sys tem.