catena-Poly[silver(I)-bis[μ-4-methyl-1H-1,2,4-triazole-3(4H)-thione-κ2 S:S]-silver(I)-di-μ-thiocyanato-κ2 S:N;κ2 N:S]

In the title one-dimensional coordination polymer, [Ag2(NCS)2(C3H5N3S)2]n, the AgI atom adopts a distorted tetrahedral AgNS3 geometry. Adjacent AgI atoms in the [001] chain are alternately linked by pairs of bridging 4-methyl-1H-1,2,4-triazole-3(4H)-thione (Hmptrz) ligands (via their S atoms) and double thiocyanate bridges linking through both S and N atoms (μ-1,3-SCN). An intrachain N—H⋯N hydrogen bond occurs between the NH group of the triazole ring and the N atom of the thiocyanate bridging ligand. A (101) sheet structure arises from interchain S⋯N short contacts [3.239 (3) Å] involving the thiocyanate S atom and the triazole-ring N atom and possible very weak π–π stacking [centroid–centroid separation = 4.0762 (18) Å] between the triazole rings.


metal-organic compounds
Financial support from the Center of Excellent for Innovation in Chemistry (PERCH-CIC), Office of the Higher Education Commission, Ministry of Education, and Graduate School, Prince of Songkla University, are gratefully acknowledge.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HB7066). One of the active areas of meterial research is the coordination compounds of the metal ions with the multifunctional ligands leading to the structural diversities and properties (Zhang et al., 2009;Wang et al., 2011). For this work, we report the mixed ligands Ag(I) complex containg multidonor atoms, 4-methyl-1,2,4-triazole-3-thiol (Hmptrz) and thiocyanate ligands. The Hmptrz is one of 1,2,4-triazole derivative ligands -based heterocyclic thioamide containing thiol group which has three potential donor atoms. Both Hmptrz and thiocyanate group are amphidentate ligands, which can bind to the metal center with either the N or S atom or both of them (Zhang et al., 1999;Jiang et al., 2011).
The title complex exhibits a one-dimensional chain polymeric structure and the asymmetric unit consists of one Ag(I) atom, one Hmptrz molecule and one SCNanion. The chemical structure of this complex is shown in Scheme I and the crystal structure is depicted in Figure 1.
The Ag atom features a distorted tetrahedral environment with the range of angles from 101.00 (2) to 124.52 (3) o . Each Ag is bonded by two µ 2 -S-bridging atoms of two Hmptrz molecules with the distances of 2.5554 (8) and 2.6688 (8) Å.
An infintite one-dimensional structure of this complex is based on [Ag(µ 2-Hmptrz)(µ 2 -1,3-SCN)] double-bridges, in which both Hmptrz and SCNligands adopt the µ 2 -end-on and µ 2 -end-to-end bridging mode, respectively. As illustated in The weak intra-molecular hydrogen bonding interaction [N1-H1···N4 i , (i) = -x + 1, -y, -z + 1] is found between N(1) of triazole ring and N(4) of thiocyanate bridging ligand at 2.954 (4) Å. The inter-short contact at 3.239 (3) Å arises from S2 donor of triazole ring with N2 acceptor from the thiocyanate bridge of the neighbouring adjacent chain which is smaller than the sum of S and N van der Waals radii (1.80 + 1.55 Å). In addition, the π···π stacking between the triazole rings of the neighbouring chain is observed with the centroid-centriod distance of 4.0762 (18)  generate the supramolecular layer interactions related by ac-plane. A view of intra-molecular hydrogen bonding is depected in Figure 3 and The layered network interactions in crystal packing are shown in Figure 4.

Experimental
A mixture of AgNO 3 (0.15 g, 0.88 mmol), KSCN (0.09 g, 0.87 mmol) in EtOH 30 ml was heated and stirred to 75 °C for 1 h. After that, the Hmptrz ligand (0.1 g, 0.087 mmol was added to the mixture and further continuous stirring for 12 h.
The colorless crystals of the complex were obtained after the colorless filtrate was kept to stand at room temperature for a day. The complex melts at 130-132°C.

Refinement
All carbon H-atom of the triazole ring and the methyl group were placed in calculated positions (C-sp 2 -H = 0.93 and Csp 3 = 0.96 Å) and were included in the refinement in the riding-model approximation, with U iso (H) = 1.2U eq (C) and U iso (H) = 1.5U eq (C), respectively. The H atom of triazole ring N atom is located in a difference map and restrained, N-H = 0.86 Å with U iso (H) = 1.2U eq (N).

Figure 1
The structure of the title complex with displacement ellipsoids plotted at the 30% probability level.  The one-dimensional chain of the title complex.

Figure 3
The intra-chain hydrogen-bonding interactions of the title complex.  The two-dimensional-layer inter-interactions of the title complex. All H atoms not involving the interactions are omitted. 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 R-factors(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.