{4′-[4-(4,4′-Bipyridin-1-ylmethyl)phenyl]-2,2′:6′,2′′-terpyridine}chloridoplatinum(II) bis(perchlorate) acetonitrile disolvate sesquihydrate

The asymmetric unit of the title compound, [PtCl(C32H24N5)](ClO4)2·2CH3CN·1.5H2O, comprises two unique PtII complex cations, four perchlorate anions, four acetonitrile solvent molecules and three water molecules. The Pt atom is four-coordinated by a tridentate chelating 2,2′:6′,2′′-terpyridine ligand and a chloride ion in a square-planar geometry with modest distortion imposed by the constraint of the terpyridyl ligand. The r.m.s. deviations from the plane comprising the four ligand donor atoms and the Pt atom are 0.0381 and 0.0472 Å in the two complex cations.

The asymmetric unit of the title compound, [PtCl(C 32 H 24 N 5 )]-(ClO 4 ) 2 Á2CH 3 CNÁ1.5H 2 O, comprises two unique Pt II complex cations, four perchlorate anions, four acetonitrile solvent molecules and three water molecules. The Pt atom is fourcoordinated by a tridentate chelating 2,2 0 :6 0 ,2 00 -terpyridine ligand and a chloride ion in a square-planar geometry with modest distortion imposed by the constraint of the terpyridyl ligand. The r.m.s. deviations from the plane comprising the four ligand donor atoms and the Pt atom are 0.0381 and 0.0472 Å in the two complex cations.

Related literature
For the synthesis of the terpyridyl ligand, see: Kronke (1976); Collin et al. (1991). For the synthesis of Pt II -terpyridyl complexes, see: Jarosz et al.
This work was supported financially by the National Basic Research Program of China (973 Program 2007CB613304) and the Foundation of the Bureau of International Cooperation of the Chinese Academy of Science (GJHZ200817).

Experimental
The ligand 4'-p-tolyl-[2,2':6',2'']terpyridine was prepared by a literature method (Kronke, 1976), and bromination was carried out in the presence of N-bromosuccinimide and a small amount of benzoyl peroxide in CCl 4 . The title complex was prepared as previously reported (Jarosz et al., 2008). The bipyridinium appended terpyridine ligand (0.56 g, 1 mmol), synthesized according to a previously reported procedure (Collin et al., 1991), was mixed with Pt(DMSO) 2 Cl 2 (0.47 g, 1.1 mmol) in 50 mL acetonitrile/chloroform (v/v, 2:1). The mixture was stirred at reflux for 30 h, and a saturated aqueous solution of sodium perchlorate was added after cooled to room temperature. The resulting orange precipitate was collected by filtration and washed with water and diethyl ether. Recrystallization by vapor diffusion of diethyl ether into a dichloromethane/acetonitrile (v/v, 1:1) mixture gave yellow crystals.

Refinement
The H atoms were placed in calculated positions [aromatic C-H = 0.93Å and Uiso(H) = 1.2Ueq(C)]. Those of the methyl groups were rotated to fit the electron densidy [ C-H = 0.96Å and Uiso(H) = 1.5Ueq(C)]. The H atoms were included in the refinements in the riding-model approximation. The water H atoms were located in a difference Fourier map and fixed in these positions with distance restraints of O-H = 0.85Å. Fig. 1. The asymmetric unit of the title compound with ellipsoids drawn at the 30% probability level.

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 supplementary materials sup-3 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.