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(H₂TCB)_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 P2₁/n with a = 1.0723(4) nm, b = 0.7168(3) nm, c = 1.7155(6) nm, β = 97.079(4)°, V = 1.3086(8) nm³, Z = 4, and final R₁ = 0.0203, wR₂ = 0.0404. In 1, the protonated carboxylate groups are free, the other carboxylate groups are bonded to Tb³⁺ ion in three modes: the chelating bidentate, the bridging bidentate and bridging tridentate. Moreover each Tb³⁺ ion is coordinated by nine oxygen atoms from six carboxylate groups and one water molecule respectively to complete a deformed tricapped trigonal prismatic geometry. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)