Molbank, Vol. 2017, Article M952: Solvent-Mediated Synthesis of M(II)-Coordination Polymer Part 1: Crystal Structure of Poly(1,2-di(4-pyridyl)ethylene-k2N,N`)-bis(1,4-benzenediacetato-k4O,O´,O´´,O´´`)zinc(II)], C22H18ZnN2O4 (Molbank)

An interaction of water-methanol solution of sodium1,4-benzenediacetate (bda) and 4,4´-bipyridylethelene (bpee) with aqueous solution of Zn(NO3)2·6H2O at room temperature yielded colourless crystals of 1 after three weeks in a sealed glass tube. The compound with composition C22H18ZnN2O4 crystallizes in monoclinic space group P21/c, with the following cell dimensions: a = 10.4566(2), b = 13.3085(2), c = 13.7189(2) Å, ? = 101.491(1)°. In the structure of 1, two Zn(II) neighbours are connected by two bda ligands adopting chelating and bidentate-bridging coordination modes to form a dimeric unit (Zn2O8N4) with the Zn-Zn distance of 4.0432(6) Å. The carboxyl-bridged dimeric units are extended along the [001] direction by bpee co-ligands and further linked by bda ligand to form a three-dimensional network structure. The IR shows the characteristic bands of the carboxylates at 1611/1507 cm-1 and 1424/1373 cm-1, respectively, for asymmetric and symmetric stretching -CO2- vibrations. The separation ?[?asym(CO2-) - ?sym(CO2-)] values of 187 and 134 cm-1 are indicative of chelating and bidentate bridging coordination modes of the carboxylate to the metal centre.