CRYSTAL-STRUCTURES OF POLYMERIC COMPLEXES OF ZINC(II) BROMIDE AND PERCHLORATE WITH 1,4-DIAZONIABICYCLO[2.2.2]OCTANE-1,4-DIACETATE

Two zinc(II) complexes containing a flexible double betaine, namely [{ Zn(L)Br-2}(n)]. nH(2)O (1), and [{Zn(L)(2)(H2O)(2)}(n)](ClO4)(2n). 4nH (2)O (2) [L = 1,4-diazoniabicyclo [2.2.2]octane-1,4-diacetate, -O2CCH2 N+(CH2CH2)(3)N+CH2CO2-], have been prepared and shown to have polymeri c structures by single-crystal X-ray analysis. Complex (1) exhibits an infinite zigzag chain in which each zinc(II) atom is coordinated by t wo unidentate carboxylate oxygen atoms and two bromide ligands in a di storted tetrahedral geometry. Complex (2) consists of an assembly of c ationic Zn(L)(2)(H2O)(2)(2+) moieties and discrete perchlorate anions as well as lattice water molecules. In (2) each zinc(II) atom is coord inated by two pairs of unidentate carboxylate oxygen atoms and two aqu a ligands in a distorted octahedral geometry and cross-linked by skele tons of double betaine ligands to form a corrugated layer structure co rresponding to the plane (100).