Crystal structure of poly[[(l3-hydroxido-j3O:O:O)-(l3-selenato-j3O1:O2:O3)tris[l3-2-(1,2,4-triazol-4-yl)acetato-j3N1:N2:O]tricopper(II)] dihydrate]

Abstract

The title coordination polymer, {[Cu3(C4H4N3O9)3(SeO4)(OH)]2H2O}n or ([Cu3(3-OH)(trgly)3(SeO4)]2H2O), crystallizes in the monoclinic space group P21/c. The three independent Cu2+ cations adopt distorted square-pyramidal geometries with {O2N2+O} polyhedra. The three copper centres are bridged by a 3-OH anion, leading to a triangular [Cu3(3-OH)] core. 2-(1,2,4-Triazol-4-yl)-acetic acid (trgly-H) acts in a deprotonated form as a 3-3N1:N2:O ligand. The three triazolyl groups bridge three copper centres of the hydroxo-cluster in an N1:N2 mode, thus supporting the triangular geometry. The [Cu3(3-OH)(tr)3] clusters serve as secondary building units (SBUs). Each SBU can be regarded as a six-connected node, which is linked to six neighbouring triangles through carboxylate groups, generating a two-dimensional uninodal (3,6) coordination network. The selenate anion is bound in a 3-3O1:O2:O3 fashion to the trinuclear copper platform. The [Cu3(OH)(trgly)3(SeO4)] coordination layers and guest water molecules are linked together by numerous O-H O and C-H O hydrogen bonds, leading to a three-dimensional structure.