Bis{3-[2-(methylsulfonyl)pyrimidin-4-yl]pyridinium} tetrachloridocadmium

In the title compound, (C10H10N3O2S)2[CdCl4], the CdII ion lies on a twofold axis and is coordinated by four chloride anions, with bond distances of 2.4787 (10) and 2.4410 (10) Å. A chain along the c axis is formed by C—H⋯N hydrogen-bonding interactions and a weak π–π interaction is observed between the pyrimidine rings of two adjacent parallel chains [centroid–centroid distance = 3.722 (2) Å]. N—H⋯Cl, CN—H⋯Cl and N—H⋯O interactions also occur.

In the title compound, (C 10 H 10 N 3 O 2 S) 2 [CdCl 4 ], the Cd II ion lies on a twofold axis and is coordinated by four chloride anions, with bond distances of 2.4787 (10) and 2.4410 (10) Å . A chain along the c axis is formed by C-HÁ Á ÁN hydrogenbonding interactions and a weakinteraction is observed between the pyrimidine rings of two adjacent parallel chains [centroid-centroid distance = 3.722 (2) Å ]. N-HÁ Á ÁCl, CN-HÁ Á ÁCl and N-HÁ Á ÁO interactions also occur.
DH is indebted to the Natural Science Fund for Colleges and Universities in Jiangsu Province (09KJD150009) for financial support.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: VN2019).

Comment
Crystal engineering of coordination compounds has attracted a great deal of attention in the recent years because of their potential as functional materials (Huang et al., 2001;Dong et al., 2008Dong et al., , 2009). One of the most efficient and powerful strategies for constructing such compounds is directed self-assembly of designed organic ligands and inorganic metal ions.
Although self-assembly directed by metal-containing species is mainly assisted by coordination bond-base approach, other non-covalent interactions such as hydrogen bonding and aromatic π-π stacking also have a significant impact on the architecture of the final product. One example is the dinuclear Zn II macrocyclic species reported by Huang et al. (2001). Here we describe the Cd II title complex.

Experimental
All solvents and chemicals were of analytical grade and were purchased from Aldrich or ACROS. They were used without further purification. For the synthesis of the title compound, a solution of CdCl 4 (6.4 mg, 0.025 mmol) in methanol (5 mL) was very slowly dropped on the top of a solution of L (11.76 mg, 0.05 mmol) in chloroform (5 mL) in a tube. Pale yellow single crystals formed after six days.

Refinement
All hydrogen atoms were geometrically positioned (C-H 0.93-0.97 Å) and refined in riding motion, with U iso (H)=1.2-1.5 U eq of the parent atom. Proton H3a was refined freely.