Hydrothermal synthesis and structure of a novel terbium coordination polymer with packing cavities, {[Tb(TCB)1/2(H2TCB)1/2(H2O)](H2O)2}n (H2TCB = 1,2,4,5-benzenetetracarboxylic acid)

A novel terbium coordination polymer {[Tb(TCB)(1/2)(H2TOB)(1/2)(H2O)](H2O)(2)}(n) (H2TCB = 1, 2, 4, 5-benzenetetracarboxylic acid) (1) has been hydrothermally synthesized and determined by single crystal X-ray diffraction method, which features a very interesting three-dimensional framework with large packing cavities. It crystallizes in the monoclinic space group P2(1)/n with a = 1.0723(4) nm, b = 0.7168(3) nm, c = 1.7155(6) nm, beta = 97.079(4)degrees, V = 1.3086(8) nm(3), Z = 4, and final R-1 = 0.0203, wR(2) = 0.0404. In 1, the protonated carboxylate groups are free, the other carboxylate groups are bonded to Tb (3+) ion in three modes: the chelating bidentate, the bridging bidentate and bridging tridentate. Moreover each Tb 31 ion is coordinated by nine oxygen atoms from six carboxylate groups and one water molecule respectively to complete a deformed tricapped trigonal prismatic geometry. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.