4,4′-(Ethene-1,2-diyl)dipyridinium 4-[2-(pyridin-4-yl)ethenyl]pyridinium octacyanidomolybdate(V) tetrahydrate

The crystal structure of the title compound, (C12H12N2)(C12H11N2)[Mo(CN)8]·4H2O, consists of 4,4′-(ethene-1,2-diyl)dipyridinium and 4-[2-(pyridin-4-yl)ethenyl]pyridinium cations disordered over the same site, an [Mo(CN)8]3− anion and four water molecules of crystallization. The eight-coordinate [Mo(CN)8]3− unit exhibits a slightly distorted square-antiprismatic geometry. In the structure, the cations (crystallographic symmetry, 2) and anions (crystallographic symmetry, 222) are arranged alternately by N—H⋯O and O—H⋯N hydrogen bonds, forming layers parallel to the bc plane. These layers are further linked through O—H⋯N hydrogen bonds, generating a three-dimensional supramolecular network.

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2006); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 In the past few years, much attention has been put into the design and construction of multi-functional materials . Octacyanometallates [M(CN) 8 ] n-(M = Mo, W; n = 3, 4) with flexible coordination modes and lower symmetries have been aggressively studied recently (Nowicka et al., 2012), because these building blocks can adopt various geometries, e.g., square antiprismatic, dodecahedral or bicapped trigonal prismatic, depending on the external environments. The combination of the [M(CN) 8 ] nprecusors and the second metal centers has produced various dimensional molecular structures and the resulting materials have displayed intriguing properties (Sieklucka et al., 2011).
However, the development of octacyano-and lanthanide-based assemblies has been somewhat hampered by the tendency of the lanthanide ions to adopt higher coordination numbers, their ability to easily adapt to a given environment, and in  (Prins et al., 2007;Tanase et al., 2008).
The average distances of Mo1-C and C-N bonds are 2.1682 and 1.156 Å, respectively, while the Mo1-CN bonds are almost linear with the maximum deviation from linearity of 3.8°.

Experimental
Single crystals of the title compound were prepared at room temperature by slow diffusion of a CH program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2006); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figure 2
The three-dimensional supramolecular network of the title compound.

4,4′-(Ethene-1,2-diyl)dipyridinium 4-[2-(pyridin-4-yl)ethenyl]pyridinium octacyanidomolybdate(V) tetrahydrate
Crystal data (C 12  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.