Poly[aqua(mu2-benzene-1,4-dicarboxylato)(mu2-4,4'-bipyridine N,N'-dioxide)cadmium(II)], a threefold interpenetrating diamond net.

In the title compound, [Cd(C(8)H(4)O(4))(C(10)H(8)N(2)O(2))(H(2)O)](n), (I), each Cd(II) atom is seven-coordinated in a distorted monocapped trigonal prismatic coordination geometry, surrounded by four carboxylate O atoms from two different benzene-1,4-dicarboxylate (1,4-bdc) anions, two O atoms from two distinct 4,4'-bipyridine N,N'-dioxide (bpdo) ligands and one water O atom. The Cd(II) atom and the water O atom are on a twofold rotation axis. The bpdo and 1,4-bdc ligands are on centers of inversion. Each crystallographically unique Cd(II) center is bridged by the 1,4-bdc dianions and bpdo ligands to give a three-dimensional diamond framework containing large adamantanoid cages. Three identical such nets are interlocked with each other, thus directly leading to the formation of a threefold interpenetrated three-dimensional diamond architecture. To the best of our knowledge, (I) is the first example of a threefold interpenetrating diamond net based on both bpdo and carboxylate ligands. There are strong linear O-H...O hydrogen bonds between the water molecules and carboxylate O atoms within different diamond nets. Each diamond net is hydrogen bonded to its two neighbors through these hydrogen bonds, which further consolidates the threefold interpenetrating diamond framework.