catena-Poly[[chloridocopper(I)]-μ-η2,σ1-3-(2-allyl-2H-tetrazol-5-yl)pyridine]

The title compound, [CuCl(C9H9N5)]n, prepared by solvothermal synthesis, is a new homometallic CuI–olefin coordination polymer in which the CuI atoms are linked by the 3-(2-allyl-2H-tetrazol-5-yl)pyridine ligands and are each bonded to one terminal Cl atom. The organic ligand acts as a bidentate ligand bridging two neighboring Cu centers through the bonds to the N atom of the pyridine ring and the double bond of the allyl group. Weak Cu⋯Cl [3.136 (8) Å), C—H⋯Cl and C—H⋯N interactions connect the coordination polymers into a three-dimensional structure.

The title compound, [CuCl(C 9 H 9 N 5 )] n , prepared by solvothermal synthesis, is a new homometallic Cu I -olefin coordination polymer in which the Cu I atoms are linked by the 3-(2allyl-2H-tetrazol-5-yl)pyridine ligands and are each bonded to one terminal Cl atom. The organic ligand acts as a bidentate ligand bridging two neighboring Cu centers through the bonds to the N atom of the pyridine ring and the double bond of the allyl group. Weak CuÁ Á ÁCl [3.136 (8) Å ), C-HÁ Á ÁCl and C-HÁ Á ÁN interactions connect the coordination polymers into a three-dimensional structure.

catena-Poly[[chloridocopper(I)]-
Under hydrothermal or solvothermal conditions some interesting reactions occur. Often new compounds can be obtained that cannot be synthesized using conventional solution techniques. In sealed tube, unstable copper(I) salt can exist under vacuum, and thus interesting copper(I) coordination compounds can be obtained (Ye et al., 2005(Ye et al., , 2007. The title compound, as colorless block crystals suitable for X-ray analysis, was obtained through solvothermal treatment of CuCl and 3-(2-allyl-2H-tetrazol -5-yl)pyridine in methanol at 75°C. Isostructural product was obtained when CuBr was used for the reaction (Wang, 2008).
The 3-(2-allyl-2H-tetrazol-5-yl) pyridine ligands bind to the copper(I) centers through the N atom of pyridine and double bond of the allyl group (C8-C9 1.364 (5) Å). The copper atom is coordinated to two olefinic organic ligands and one terminal Cl atom in a trigonal environment (Fig 1, Table 1). The organic ligands link the neighboring Cu centers to form a homometallic Cu(I) coordination polymer developing along the c axis. Unfortunately, the N atoms of the tetrazole ring fail to coordinate to Cu(I) (Fig. 1).
Finally, weak Cu-Cl (3.136 Å), C-H···Cl and C-H···N interactions between the coordination polymers lead to the formation of the three-dimensional structure (Fig. 2).

Experimental
A mixture of 3-(2-allyl-2H-tetrazol-5-yl)pyridine(20 mg, 0.2 mmol), CuCl (17.9 mg, 0.2 mmol) were placed in a thick Pyrex tube (ca 20 cm in length). After addition of methanol, the tube was frozen with liquid nitrogen, evacuated under vaccum, sealed with a torch and kept at 348 K. Colorless block-shaped crystals suitable for X-ray analysis were obtained after 5 d (yield 61% based on the organic ligand).

Refinement
All H atoms were fixed geometrically and treated as riding with C-H = 0.93 Å (aromatic), 0.97 Å (methylene) and 0.96Å (methyl) with U iso (H) = 1.2U eq (Caromatic, Cmethylene) and U iso (H) = 1.5U eq (Cmethyl). Fig. 1. A view of the title compound with displacement ellipsoids shown at the 30% probability level [symmetry codes: A: x, y -1, z + 1; B: x, y + 1, z -1; C: x, y + 2, z -2.  Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.