A second polymorph of catena-poly[[(1,10-phenanthroline-κ2 N,N′)copper(II)]-di-μ-thiocyanato-κ2 N:S;κ2 S:N]

In the title coordination polymer, [Cu(NCS)2(C12H8N2)]n, the CuII atom is situated on a twofold rotation axis and is coordinated by two N atoms from the bidentate 1,10-phenanthroline ligand and four thiocyanate groups to confer a CuN4S2 octahedral geometry and resulting in a layer structure extending parallel to (100).

In the title coordination polymer, [Cu(NCS) 2 (C 12 H 8 N 2 )] n , the Cu II atom is situated on a twofold rotation axis and is coordinated by two N atoms from the bidentate 1,10phenanthroline ligand and four thiocyanate groups to confer a CuN 4 S 2 octahedral geometry and resulting in a layer structure extending parallel to (100).

Comment
Phenanthroline and its derivatives have been achieving rapidly increasing attention not only for their potential application as functional materials, but aslo from their intriguing variety of architectures and topologies. 1, 10-Phenanthroline, as one kind of those ligand, has usually been used to construct a great variety of structurally interesting entities, such as monomers (Breneman et al. 1993), ploymers (Kulkarni et al. 2002;Morpurgo et al. 1984).
The structure of the title compound (I) is illustrated in Fig. 1. the Cu II atom is coordinated by two N atoms from1, 10-Phenanthroline ligand, as well as by the two N atoms and two S atoms from four thiocyanate groups to confer a distorted octahedral coordination at the metal centre. Two S atoms occupy the axial position, showing weak interaction of Cu1-S1 bond [2.952 (3)], which give rise to one-dimensional chain along (100), the crystal packing is stabilized by the intermolecular π-π stacking interaction (Fig. 2).
In contrast to the first polymorph of this composition in which the distance of Cu-S bonds are longer [3.163 (2)  99.1 (1)°, which make the octahedral geometry of this compound more disordered than the title compoud.

Experimental
The mixture of CuSCN (0.0244 g, 0.2 mmol), 1, 10-Phenanthroline (0.0132 g, 0.1 mmol), were placed and sealed in a 10 ml Teflon-lined stainless steel reactor and heated to 160 °C for 72 h, then cooled down to room temperature at a rate of 5°C / 60 min. Single crystals suitable for X-ray diffraction were obtained in the form of black bars in ca 35% yield.
The web of checkcif show one Alert level B(Hirshfeld Test Diff S1 -C7..8.52 su), we think this is the result of the sightly distorted S atom of the thiocyanate group for his weak interaction to the Cu atom.

Special details
Geometry. All e.s. 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.