Crystal structure of poly[[(μ(3)-hydroxido-κ(3) O:O:O)(μ(3)-selenato-κ(3) O (1):O (2):O (3))tris­[μ(3)-2-(1,2,4-triazol-4-yl)acetato-κ(3) N (1):N (2):O]tricopper(II)] dihydrate]

The title coordination polymer, {[Cu(3)(C(4)H(4)N(3)O(9))(3)(SeO(4))(OH)]·2H(2)O}(n) or ([Cu(3)(μ(3)-OH)(trgly)(3)(SeO(4))]·2H(2)O), crystallizes in the monoclinic space group P2(1)/c. The three independent Cu(2+) cations adopt distorted square-pyramidal geometries with {O(2)N(2)+O} polyhedra. The three copper centres are bridged by a μ(3)-OH anion, leading to a triangular [Cu(3)(μ(3)-OH)] core. 2-(1,2,4-Triazol-4-yl)acetic acid (trgly-H) acts in a deprotonated form as a μ(3)-κ(3) N (1):N (2):O ligand. The three triazolyl groups bridge three copper centres of the hydroxo-cluster in an N (1):N (2) mode, thus supporting the triangular geometry. The [Cu(3)(μ(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 μ(3)-κ(3) O (1):O (2):O (3) fashion to the trinuclear copper platform. The [Cu(3)(OH)(trgly)(3)(SeO(4))] 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.