Poly[aqua(mu3-benzene-1,2-dicarboxylato)bis(mu3-hydroxido)bis(mu2-isonicotinato)dierbium(III) monohydrate] and the thulium analogue.

The two isomorphous lanthanide coordination polymers, {[Ln(2)(C(6)H(4)NO(2))(2)(C(8)H(4)O(4))(OH)(2)(H(2)O)].H(2)O}(n) (Ln = Er and Tm), contain two crystallographically independent Ln ions which are both eight-coordinated by O atoms, but with quite different coordination environments. In both crystal structures, adjacent Ln atoms are bridged by mu(3)-OH groups and carboxylate groups of isonicotinate and benzene-1,2-dicarboxylate ligands, forming infinite chains in which the Er...Er and Tm...Tm distances are in the ranges 3.622 (3)-3.894 (4) and 3.599 (7)-3.873 (1) A, respectively. Adjacent chains are further connected through hydrogen bonds and pi-pi interactions into a three-dimensional supramolecular framework.