Synthesis and characterization of a new strontium(II) coordination polymer based on a μ2-tridentate bridging zwitterionic glycine

Abstract

The synthesis and characterization of a new Sr(II) coordination polymer (CP), [Sr(H2O)(H-gly)2Cl2] n (1) (H-gly = glycine), is described. Compound 1 crystallizes in the centrosymmetric orthorhombic space group Pcnb and its structure consists of a central Sr(II), a water molecule, a zwitterionic glycine, and a chloride. The central metal is nine coordinate, bonded to six oxygens from four different bridging H-gly ligands, two symmetry-related chlorides, and a terminal water molecule. The μ2-tridentate bridging zwitterionic glycine results in the formation of a 1-D CP with an Sr···Sr separation of 4.560 Å across the chain. The chloride, H-gly, and coordinated water are involved in five varieties of hydrogen bonding. A comparative study of the structural chemistry of several alkaline-earth glycine compounds is described.