METAL-BETAINE INTERACTIONS .1. CRYSTAL-STRUCTURE OF POLYMERIC TRANS-DIAQUABIS(PYRIDINE BETAINE)MANGANESE(II) DICHLORIDE

A new polymeric betaine complex of manganese(II), of stoichiometry [Mn(C5H5NCH2COO)2 (H2O)2]Cl2, has been prepared and characterized by infrared spectroscopy and X-ray crystallography. The complex exhibits strong carboxylate absorptions at 1624, 1396, 1384, and 715 cm-1. The crystal structure has been refined to R(F) = 0.057 for 2342 observed (\F(o)\ > 6 sigma \F(o)\ Mo K alpha data. The complex consists of a packing of syn-anti carboxylate-bridged, one-dimensional polymeric chains running parallel to the a axis. Each Mn(II) atom is located at an inversion center, with aqua ligands occupying the trans positions in a slightly distorted octahedron. The chloride ions and aqua ligands are alternately linked by O-H... Cl hydrogen bonds into a (Cl-.H2O) infinity zigzag chain also running parallel to the a axis.