Crystal structure of catena-poly[[aqua(2,2′:6′,2′′-terpyridine-κ3 N,N′,N′′)cobalt(II)]-μ-cyanido-κ2 N:C-[dicyanidoplatinum(II)]-μ-cyanido-κ2 C:N]

The title compound, [Co(C15H11N3)(H2O){Pt(CN)4}]n, is a one-dimensional coordination polymer formed under hydrothermal reaction conditions. The CoII site has sixfold coordination with a distorted octahedral geometry, while the PtII ion is coordinated by four cyanide groups in an almost regular square-planar geometry. The compound contains twofold rotation symmetry about its CoII ion, the water molecule and the terpyridine ligand, and the PtII atom resides on an inversion center. trans-Bridging by the tetracyanidoplatinate(II) anions links the CoII cations, forming chains parallel to [-101]. Additionally, each CoII atom is coordinated by one water molecule and one tridentate 2,2′:6′,2′′-terpyridine ligand. O—H⋯N hydrogen-bonding interactions are found between adjacent chains and help to consolidate the crystal packing. In addition, relatively weak π–π stacking interactions exist between the terpyridine ligands of adjacent chains [interplanar distance = 3.464 (7) Å]. No Pt⋯Pt interactions are observed in the structure.

The neutral, one-dimensional [Co (C 15  and also weak π-stacking interactions (3.464 (7) Å). Also worth noting is the orientation of the coordinated tpy molecules in the one-dimensional chains; viewing parallel to the chain reveals that these molecules are located on alternating sides of the chains. A similar situation also occurs in [Eu (C 15 (Smith, et al., 2012) contains one-dimensional chains where all of the terpyridine molecules reside on a single side of the chain. There are not any platinophilic (Pt···Pt) interactions in this compound as observed in many previous tetracyanoplatinate salts (Gliemann & Yersin, 1985).

S2. Synthesis and Crystallization
The title compound was synthesized by first mixing aqueous solutions of 0.05 M CoClO 4 and 0.05 M K 2 [Pt(CN) 4 ] (500 µL each). A pink precipitate was immediately formed which was then separated from the mother liquor by centrifugation followed by decantation. The resultant pink solid was placed in an oven at 110 °C for approximately one hour during supporting information which time it underwent a color transformation from pink to violet purple. A few milligrams of the powder was placed into a 23 mL teflon-lined Parr reaction vessel with 500 µL of deionized water. The reaction vessel was then heated in a box oven at 110 °C for 72 hours. During this process, impregnated 2,2′:6′,2"-terpyridine leached out of the teflon liner into the reaction. Once the reaction vessel had cooled pink needle-shaped single crystals of the title compound were isolated.

S3. Refinement
Crystal data, data collection and structure refinement details are summarized in Table 1. H-atoms were placed in calculated positions and allowed to ride during subsequent refinement, with U iso (H) = 1.2U eq (C) and C-H distances of 0.93 Å for ring hydrogens and U iso (H) = 1.5U eq (O) and O-H distances of 0.85 Å for hydrogen atoms of the water.

Figure 1
A ball-and-stick representation of the one-dimensional chains in (I).

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > 2σ(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