Lanthanide coordination polymers with dicarboxylate-like ligands: crystal structures of polymeric lanthanum(III) and terbium(III) complexes with flexible double betaines

Four novel polymeric lanthanide(III) complexes of two new double betaine de rivatives have been synthesized and structurally determined. In [{La-2(L-1) (2)(H2O)(9)}(n)]Cl-6n. 2nH(2)O (1) and [{Tb(L-1)(H2O)(4)}(n)]Cl-3n. nH(2)O (2) (L-1 =4,4'-trimethylenedipyridinio-N,N'-diacetate), the lanthanide(III) ions form a two-dimensional layer in which each pair of lanthanide(III) io ns is bridged by two syn-anti mu-carboxylato-O,O' groups. Adjacent layers a re cross-linked through hydrogen bonds among aqua ligands, lattice water mo lecules and chloride ions, to form a three-dimensional network. Isomorphous [{Ln(L-1)(H2O)(4)}(n)]Cl-3n. 5nH(2)O (Ln=La, 3; Ln=Tb, 4; L-2=1,3 bis(pyri dinio-4-carboxylato)-propane) each contain a centrosymmetric paddle-wheel-l ike dimeric unit in which each pair of adjacent metal atoms is bridged by f our syn-syn mu-carboxylato-O,O' groups that are oriented nearly perpendicul ar to each other about the metal-metal axis. Neighboring dimeric subunits a re bridged by a pair of flexible LL ligands into a polymeric chain. Adjacen t chains are inter-linked by hydrogen bonds among aqua ligands, lattice wat er molecules and chloride ions into a three-dimensional network. (C) 1999 E lsevier Science Ltd. All rights reserved.