catena-Poly[[[diaquacopper(II)]-bis(μ2-di-4-pyridyl disulfide-κ2 N:N′)] bis(hydrogen phthalate) monohydrate]

The asymmetric unit of the title compound, {[Cu(C10H8N2S2)2(H2O)2](C8H5O4)2·H2O}n, contains one CuII ion, two bridging di-4-pyridyl disulfide (4-DPDS) ligands of the same chirality, two coordinating water molecules, two hydrogen phthalate anions and one uncoordinated water molecule. The polymeric structure consists of two types of polymeric chains, each composed from repeated chiral rhomboids. The CuII ions adopt a distorted octahedral coordination geometry and are coordinated by four pyridine N atoms and two water O atoms. The coordinated water molecules and hydrogen phthalate anions are located between the repeated rhomboidal chains, and form hydrogen bonds with the coordinated water molecules.

The asymmetric unit of the title compound, {[Cu(4-DPDS) 2 (H 2 O) 2 ].2(C 8 H 5 O 4 ) -.H 2 O} n (4-DPDS = 4,4'dipyridinedisulfide),contains one Cu II ion, two bridging 4-DPDS ligands of the same chirality, two coordinating water molecules, two hydrogen phthalate anions and one lattice water molecule (Fig. 1). The copper atoms are each coordinated by four pyridine nitrogen atoms and two aqua ligands to complete an elongated octahedral CuN 4 O 2 chromophore of "4 + 2" coordination type due to Jahn-Teller effect. The equatorial positions are occupied by four N toms of four 4-DPDS ligands, and the axial ones by two aqua O atoms. The Cu-O distances of 2.513 (3) Å and 2.438 (3) Å are significantly larger than those to the nitrogen atoms (Cu-N = 2.031 (3)-2.054 (3) Å), indicating a weak coordination capability of the aqua ligand.
The cis and trans N-Cu-N angles fall in the regions 88.97 (9)-90.99 (9)° and 173.34 (13)-176.78 (12)°, respectively, exhibiting small deviation from the corresponding values for a regular geometry. The bond lengths (with the Cu atoms) are all within the normal ranges (Manna et al., 2007).
The Cu atoms are bridged by four 4-DPDS ligands to form one-dimensional double-stranded chains extending in the [010] direction. The one-dimensional chains with respect to the neighbour are close-packed in ···ABAB··· sequence (Fig. 2). Despite the Cu-Cu distance spanned by the two 4-DPDS are 10.732 (2) Å, but no similar mesoporous structure form, because the HLanions and lattice H 2 O molecule reside in cavities in the one-dimensional chain metallacycle. The HLanions play a role in balancing in charge, the carboxylic -COOH groups favor formation of strong intramolecular hydrogen bond to carboxylate O6 atom and O11 atom, and the lattice H 2 O molecule form hydrogen bonds to two HLainions. The distance of S-S between adjacent chains is 5.17 (1) Å, which is much greater than van der waals distance (3.7 Å), shows that there is no S-S weak interaction.The chains are linked via those interchain hydrogen bonds between the aqua ligand and the carboxylate atoms (Table 1) into two-dimensional layers (Fig. 3).

Experimental
Dropwise addition of 0.5 ml 1.0 M NaOH to a aqueous solution of Cu(NO 3 ) 2 .3H 2 O (0.0603 g, 0.25 mmol) in 4 ml H 2 O produced the blue precipitate, which was then centrifuged and washed with double-distilled water four times. The precipitate was subsequently moved to a stirred suspension of phthalic acid (0.0510 g, 0.25 mmol) and DPDS (4,4'-dipyridinedisulfide) (0.0575 g, 0.25 mmol) in 30 ml hot water. The mixture was further stirred for 30 min and the insoluble solid was filtere off. The colourless filtrate was allowed to stand at the room temperature. Slow evaporation for about a month afforded a small amount of blue block crystals.

Refinement
H atoms bonded to C atoms were geometrically positioned and were refined using a riding model, with U iso (H) = 1.2 U eq (C).
H atoms attached to O atoms were found in a difference Fourier synthesis and were refined using a riding model, with the O-H distances fixed as initially found and with U iso (H) values set at 1.2 Ueq(O).