catena-Poly[[iodidocopper(I)]-μ-4,4′,6,6′-tetramethyl-2,2′-(ethylenedithio)dipyrimidine-κ2 N:N′]

In the title coordination polymer, [CuI(C14H18N4S2)]n, the CuI center is trigonally coordinated by two pyrimidine N-atom donors from two distinct dithioether ligands and one iodide anion. The Cu and I atoms are located on a twofold axis, whereas the midpoint of the central C—C bond of the dithioether ligand is located on an inversion center. Each organic ligand, acting in a bidentate mode, bridges two CuI ions, resulting in the formation of polymeric zigzag chains. The dihedral angle between the two pyrimidine units bonded to the metal center is 88.01 (2)°. The crystal packing is mainly stabilized by van der Waals forces and π–π stacking interactions, with an interplanar distance between the pyrimidine rings of adjacent chains of 3.638 (3) Å.

In the title coordination polymer, [CuI(C 14 H 18 N 4 S 2 )] n , the Cu I center is trigonally coordinated by two pyrimidine N-atom donors from two distinct dithioether ligands and one iodide anion. The Cu and I atoms are located on a twofold axis, whereas the midpoint of the central C-C bond of the dithioether ligand is located on an inversion center. Each organic ligand, acting in a bidentate mode, bridges two Cu I ions, resulting in the formation of polymeric zigzag chains. The dihedral angle between the two pyrimidine units bonded to the metal center is 88.01 (2) . The crystal packing is mainly stabilized by van der Waals forces andstacking interactions, with an interplanar distance between the pyrimidine rings of adjacent chains of 3.638 (3) Å .

Related literature
For applications of closed-shell metal atoms or ions, see: Catalano et al. (2000). For applications of conjugated multibranched molecules in optical materials, see: Nishihara et al. (1989); Roberto et al. (2000). For the structures of CuI complexes with similar ligands, see: Shi et al. (2008).

Comment
Previous studies have shown that the bonding interaction between closed-shell metal atoms or ions is gaining increasing attention (Catalano et al., 2000), there are a few reports of similar association in the case of alkyl copper (I) complexes. Heterocycle-based aromatic systems with conjugated multi-branched structure possess potential applications in optical image processing, all-optical switching, and integrated optical devices (Nishihara et al., 1989;Roberto et al., 2000). Pyrimidine is a π-electron deficient with its ionization potential value of 10.41 eV and metal complexes of such ligand has been reported (Shi et al., 2008). On the other hand, pyrimidine ring has well known reactivity in the positions 4 and 6, which can easily undergo reactions with an aromatic aldehyde in solvent-free condition. Therefore we pay our attention to the pyrimidine system. As part of our ongoing investigation on d 10 ions and pyrimidine derivatives, the title compound, has been prepared and its crystal structure is presented here.
The molecular structure of the title compound shows that Cu atom coordinated in a triangle-planar configuration ( Fig.   1) with two equal Cu-N and one Cu-I bonds ( Table 1). The dihedral angles formed by the two pyrimidine rings (N1, C2, N2, C6, C5, C3 and N1A, C2A, N2A, C6A, C5A, C3A) is 88.01 (2)°. Each ligand, acting in a bidentate mode, bridges two Cu ions, resulting in the formation of polymeric zigzag chains. The crystal packing is mainly stabilized by van der Waals forces and π-π interactions, with the shortest distance of 3.938 (3)Å along c axis.

Refinement
All H atoms were positioned geometrically with C-H =0.97 and 0.96 Å for methylene and methyl H atoms, respectively, and constrained to ride on their parent atoms, with U iso (H) = xU eq (C), where x = 1.5 for methyl H and x = 1.2 for methylene H atoms.

catena-Poly[[iodidocopper(I)]-µ-4,4',6,6'-tetramethyl-2,2'-(ethylenedithio)dipyrimidine-κ 2 N:N']
Crystal data [CuI(C 14   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.
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )