Specificity of structure of zinc(2) halides with cyclic tetraaminne ligands. Crystal structures of ZnCyclamX2, X=Cl, Br, I

Crystal structure of ZnCyclamX2, X=Cl, Br, I, Cyclam(C10H24N4)=1,4,8,11-tetraazacyclotetradecane, was defined. The complexes are monomer tetragonally-bipyramid structures with meso-planar conformation Cyclam. Metal atoms is statistically shifted from equatorial plane by 0.24 A in case X=Cl; 0.33 A - X=Br; and 0.40 A - X=I. Secondary (elongated) axial bonds are nonequilibrium: Zn-Cl 2.424(8) and 2.0905(8) A, Zn-Br 2.555(4) and 3.214(4) A; Zn-I 2.753(1) and 3.543(1) A. Judging by geometry of the complexes and 13C[1H]NMR data statistical shift of Zn is dynamic character. The assumption is made that intramolecular motion increases stability of the complexes and characterizes specific type of binding, inherent of d10-metal complexes. It is shown that antibate correlation in the lengths of equatorial and axial bonds ascertained for slightly distorted octahedral complexes is just both for pyramid and bipyramid complexes with axial long-range action