A double-layered zinc(II) coordination polymer with the ligand 3,5-bis(carboxylatomethoxy)benzoate.

In the title compound, poly[hexaaquabis[mu(4)-3,5-bis(carboxylatomethoxy)benzoato]trizinc(II)], [Zn(3)(C(11)H(7)O(8))(2)(H(2)O)(6)](n), there are two crystallographically distinct Zn(II) cations which are bridged by polycarboxylate ligands in a mu(4)-bridging mode. A pair of ligands bridges adjacent Zn atoms to give centrosymmetric dimetal building blocks which act as four-connected nodes to be further interlinked into a two-dimensional double-layered framework with (4,4) topology. Other Zn atoms, lying on inversion centres, occupy the cavities of this topological structure. This submission shows a versatile polycarboxylate ligand with rigid and flexible functional groups, the co-operation and complementarity of which would meet the coordination requirements of a variety of topological structures.

{µ-trans-N,N'-Bis[(diphenyl-phosphan-yl)meth-yl]benzene-1,4-diamine-κP:P'}bis-{(acetonitrile-κN)[dipyrido[3,2-a:2',3'-c]phenazine-κN,N]copper(I)} bis-(tetra-fluoridoborate).

In the centrosymmetric dinuclear title compound, [Cu(2)(C(2)H(3)N)(2)(C(18)H(10)N(4))(2)(C(32)H(30)N(2)P(2))](BF(4))(2), the Cu(I) centre is coordinated by two N atoms from a dipyridophenazine ligand, one P atom from an N,N'-bis-[(diphenyl-phosphan-yl)meth-yl]benzene-1,4-diamine (bpbda) ligand, and one N atom from an acetonitrile mol-ecule in a distorted tetra-hedral geometry. The bpbda ligand, lying on an inversion center, bridges two Cu(I) centres into a Z-shaped complex. Intra-molecular π-π inter-actions between the dipyridophenazine ligand and the benzene ring of the bpbda ligand are observed [centroid-centroid distance = 3.459 (3) Å]. The crystal structure also involves inter-molecular π-π inter-actions between the dipyridophenazine ligands [centroid-centroid distance = 3.506 (3) Å], which lead to a one-dimensional supra-molecular structure.

Tetra-aqua-bis(2-methyl-benzimidazolium-1,3-diacetato-κO)zinc(II) tetra-hydrate.

The asymmetric unit of the title compound, [Zn(C(12)H(11)N(2)O(4))(2)(H(2)O)(4)]·4H(2)O, contains one-half of the complex mol-ecule and two uncoordin-ated water mol-ecules. The four water O atoms in the equatorial plane around the Zn(II) centre ( symmetry) form a distorted square-planar arrangement, while the distorted octa-hedral coordination geometry is completed by the O atoms of the zwitterionic 2-methyl-benzimidazolium-1,3-diacetate ligands in the axial positions. The benzimidazole ring system is planar, with a maximum deviation of 0.041 (3) Å. Intra-molecular O-H⋯O hydrogen bonding results in the formation of a non-planar six-membered ring. In the crystal structure, strong intra- and inter-molecular O-H⋯O hydrogen bonds link the mol-ecules into a three-dimensional network. π-π contacts between benzimidazole rings [centroid-centroid distance = 3.899 (1) Å] may further stabilize the structure.

A coordination polymer of CdCl2 with the novel zwitterionic dicarboxylate ligand 2,2'-(2-methylbenzimidazolium-1,3-diyl)diacetate (pda).

The title compound, poly[chlorido[mu(4)-2,2'-(2-methylbenzimidazolium-1,3-diyl)diacetato]cadmium(II)], [Cd(C(12)H(11)N(2)O(4))Cl](n), is an undulating two-dimensional polymer consisting of a paddlewheel Cd(2)(CO(2))(4) cluster which lies on an inversion centre. These paddlewheel clusters act as four-connected square building units interlinked via bridging zwitterionic dicarboxylate ligands into a corrugated layer which is consolidated by pi-pi interactions between benzene rings of benzimidazole groups. Neighbouring layers are further assembled via interlayer pi-pi interactions into a three-dimensional supramolecular structure. The key feature of this study is the synthesis of a paddlewheel-based polymer constructed with a novel multifunctional zwitterionic dicarboxylate ligand.