Poly[(μ2-3,6-di-4-pyridyl-1,2,4,5-tetrazine)(μ2-thiocyanato)copper(I)]

The title compound, [Cu(NCS)(C12H8N6)]n, is a self-assembled two-dimensional metal–organic network. The Cu atom is linked by two N atoms from two 3,6-di-4-pyridyl-1,2,4,5-tetrazine ligands and by the N and S atoms from two thiocyanate ligands in a distorted tetrahedral environment. The Cu atom and the thiocyanate ligand occupy a crystallographic mirror plane m, and a crystallographic inversion centre is in the middle of the tetrazine ring, generating the zigzag fashion of the two-dimensional network. The infinite –Cu—SCN—Cu—SCN– chain is due to translational symmetry along the a axis. These chains are further connected through the 3,6-di-4-pyridyl-1,2,4,5-tetrazine ligands that bridge the CuI centers, generating a two-dimensional network. There are π—π stacking interactions between the pyridine and tetrazine rings (perpendicular distances of 3.357 and 3.418 Å), with a centroid–centroid distance of 3.6785 (16) Å.

The title compound, [Cu(NCS)(C 12 H 8 N 6 )] n , is a selfassembled two-dimensional metal-organic network. The Cu atom is linked by two N atoms from two 3,6-di-4-pyridyl-1,2,4,5-tetrazine ligands and by the N and S atoms from two thiocyanate ligands in a distorted tetrahedral environment. The Cu atom and the thiocyanate ligand occupy a crystallographic mirror plane m, and a crystallographic inversion centre is in the middle of the tetrazine ring, generating the zigzag fashion of the two-dimensional network. The infinite -Cu-SCN-Cu-SCN-chain is due to translational symmetry along the a axis. These chains are further connected through the 3,6-di-4-pyridyl-1,2,4,5-tetrazine ligands that bridge the Cu I centers, generating a two-dimensional network. There are stacking interactions between the pyridine and tetrazine rings (perpendicular distances of 3.357 and 3.418 Å ), with a centroid-centroid distance of 3.6785 (16) Å .

Comment
The coordination polymers that based on metal halides and N-donor ligands are one of the most important and promising fields in magnetism, nonlinear optics, electronics, catalysis and molecular topologies (Oxtoby et al., 2003;Hsu et al., 2006), the title compound is an example.

Experimental
CuSCN (12.2 mg) and NH 4 SCN(1.4 mg) were added into 2.5 ml DMF and the solution were stirred for 10 min at room temperature until became clarification. Then, the resulting solution was subsequently filterated to a tube, then 2.5 ml solution of i.-pron and 3,6-di-4-pyridyl-1,2,4,5-tetrazine added to afford a black filtrate. Many prismatic black crystals were obtained a few weeks later.

Refinement
H atoms were positioned geometrically and refined as a riding model, with U iso (H) = 1.2U eq (pyridyl C atoms). The C-H bond lengths are 0.93 Å.
supplementary materials sup-2 Figures   Fig. 1. A section of the two-dimensional structure of the title complex, with atom labels and 30% probability displacement ellipsoids. H atoms have been omitted. [symmetry codes: i = -1 + x, y, z; ii = 1 + x, y, z; iii = x, 1/2 -y, z; iv = -1 -x, -y, 1 -z.] 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.