Dichloridobis[3-(4-chlorophenyl)-2,N,N-trimethyl-2,3-dihydro-1,2,4-oxadiazole-5-amine-κN 4]platinum(II)–4-chlorobenzaldehyde (1/1)

In the title 1:1 co-crystal, [PtCl2(C11H14ClN3O)2]·C7H5ClO, the coordination polyhedron of the PtII atom is slightly distorted square-planar with the chloride and 2,3-dihydro-1,2,4-oxadiazole ligands mutually trans, as the Pt atom lies on an inversion center. The 4-chlorobenzaldehyde molecules are statistically disordered about an inversion centre with equal occupancies for the two positions. The PtII complex forms a three-dimensional structure through C—H⋯Cl and weaker C—H⋯O interactions with the 4-chlorobenzaldehyde molecule.

In the title 1:1 co-crystal, [PtCl 2 (C 11 H 14 ClN 3 O) 2 ]ÁC 7 H 5 ClO, the coordination polyhedron of the Pt II atom is slightly distorted square-planar with the chloride and 2,3-dihydro-1,2,4-oxadiazole ligands mutually trans, as the Pt atom lies on an inversion center. The 4-chlorobenzaldehyde molecules are statistically disordered about an inversion centre with equal occupancies for the two positions. The Pt II complex forms a three-dimensional structure through C-HÁ Á ÁCl and weaker C-HÁ Á ÁO interactions with the 4-chlorobenzaldehyde molecule.

Experimental
Crystal data [PtCl 2 (C 11 H 15 Table 1 Hydrogen-bond geometry (Å , ).  In the past decade, a great attention has been paid to metal-mediated cycloaddition (CA) of various dipoles to nitriles.
Indeed, the activation of nitrile substrates by a metal center often results in promotion of CAs, which are not feasible in the so-called pure organic chemistry. In addition, metal-mediated CA represents an efficient route to free and/or coordinated heterocycles that could be either difficult to obtain or even inaccessible via metal-free protocols (Bokach et al., 2011;Bokach & Kukushkin, 2006). Furthermore, an interest in platinum complexes with 2,3-dihydro-1,2,4-oxadiazole as a ligand is caused by their potential applications in medicine.
In 1, the complex molecule contains one crystallographically independent Pt atom that lies on an inversion center and is coordinated by two equivalent Clanions and two N atoms ( Fig. 1) of the heterocyclic ligands each of which are mutually trans. The Pt(1)-N(1) bond length is typical for (imine)Pt II species (Allen et al., 1987). The N(4)-C(5) (1.301 (4) Å) distance is characteristic for the N=C double bond (Fritsky et al., 2006;Penkova et al., 2009), while the N(4)-C(3) and N(2)-C(3) (1.476 (4) and 1.474 (4), respectively) are specific for the N-C single bonds (Allen et al., 1987). Both asymmetric C(3) atoms in the heterocyclic ligands exhibit the same configuration (RR/SS). The p-chlorobenzaldehyde molecules are statistically disordered about an inversion centre with equal occupancies for the two half-occupied positions.
The platinum complexes are arranged in layers parallel to the (001) plane (Fig. 2). The p-chlorobenzaldehyde molecules occupy sites in between the layers of platinum(II) complexes.

Experimental
The platinum complex was synthesized by a cycloaddition reaction between the complex trans-[PtCl 2 (NCNMe 2 ) 2 ] and the nitrone p-ClC6H4C(H)=N(O)Me as described previously (Kritchenkov et al., 2011). Crystals of 1 were obtained from the reaction mixture by slow evaporation of the solvent (dichloromethane) at room temperature; p-chlorobenzaldehyde was generated in the reaction mixture by hydration of the nitrone in the undried solvent.

Refinement
The carbon-and nitrogen-bound H atoms were placed in calculated positions and were included in the refinement in the riding model approximation, with U iso (H) set to 1.5U eq (C) and C-H 0.96 Å for the methyl groups, 1.2U eq (C) and C-H 0.98 Å for the tertiary CH groups, 1.2U eq (C) and C-H 0.93 Å for the carbon atoms of the benzene rings and aldehyde group, and 1.2U eq (N) and N-H 0.91 Å for the tertiary NH groups.    where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 1.63 e Å −3 Δρ min = −1.21 e Å −3 Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. 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^ > 2sigma(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Occ. (