Terbium-oxalate-pyridinedicarboxylate coordination polymers suggesting the reductive coupling of carbon dioxide (Co2) to oxolate (C2O42-):: [Tb2 (3,5-PDC)2(H2O)4(C2O4)]•2H2O and [Tb(2,4-PDC) (H2O) (C2O4)0.5] (PDC = pyridinedicarboxylate)

Under hydrothermal conditions, Tb(NO3)(3).5H(2)O reacted with 3,5-pyridinedicarboxylic acid (3,5-PDCH2) to give a 3-D coordination polymer with the empirical formula of [Tb-2 (3,5-PDC)(2)(H2O)(4)(C2O4)].2H(2)O (1). Tb(NO3)(3).5H(2)O also reacted with 2,4-pyridinedicarboxylic acid (2,4-PDCH2) to give another 3-D coordination polymer [Tb-2 (2,4-PDC)(2)(H2O)(2)(C2O4)] (2). The structures of both polymers have been determined by X-ray diffraction. X-ray structure analyses show that both polymers contain bridging oxalate (C2O42-) ligands, which might have been formed by the reductive coupling of CO, molecules released from the PDC2- ligands through the C-C bond cleavage. (C) 2002 Elsevier Science B.V. All rights reserved.