Trichlorido(4-methylbenzyl)bis(1H-pyrazole-κN 2)tin(IV)

The six-coordinate SnIV atom in the title compound, [Sn(C8H9)Cl3(C3H4N2)2], shows an octahedral coordination. The N atoms of the N-heterocycle are cis to each other. The Sn—N bond that is trans to the Sn—C bond is shorter than the Sn—N bond trans to the Sn—Cl bond. Weak N—H⋯Cl hydrogen bonds link adjacent molecules, generating a double chain running along the c axis.

The six-coordinate Sn IV atom in the title compound, [Sn(C 8 H 9 )Cl 3 (C 3 H 4 N 2 ) 2 ], shows an octahedral coordination. The N atoms of the N-heterocycle are cis to each other. The Sn-N bond that is trans to the Sn-C bond is shorter than the Sn-N bond trans to the Sn-Cl bond. Weak N-HÁ Á ÁCl hydrogen bonds link adjacent molecules, generating a double chain running along the c axis.

Comment
Dibenzyltin dichloride and benzyltin trichloride can be synthesized by the direct action of benzyl chloride on stannous chloride; other ring-substituted analogs are similarly synthesized (Sisido et al., 1961). The title compound results from the reaction of di(4-methylbenzyl)tin dichloride with pyrazole to afford the pyrazole adduct of a monoorganotin trichloride.
There are few examples of monororganotin chlorides forming adducts with N-heterocycles. Phenyltin trichloride forms a 1:2 adduct with pyrazole (Casas et al., 1996). The 4-methylbenzyl analog affords a similar 1:2 adduct. The six-coordinate Sn IV atom in SnCl 3 (C 8 H 9 )(C 3 H 4 N 2 ) 2 (Scheme I) shows octahedral coordination. The N atoms of the N-heterocycle are cis to each other and the three Cl atoms are coplanar (Fig. 1). The geometry can be described as being a mer-octahedron. The Sn-N bond that is trans to the Sn-C bond is shorter than the Sn-N bond trans to the Sn-Cl bond.

Experimental
Di(4-methylbenzyl)tin dichloride was synthesized by using a literature procedure (Sisido et al., 1961). The compound (0.4 g, 1 mmol) and pyrazole (0.136 g, 2 mmol) of pyrazole were dissolved in ethanol (100 ml) and the solution was heated for an hour. The solution was filtered and then set aside for the growth of colorless crystals.

Refinement
Carbon-bound H-atoms were placed in calculated positions (C-H 0.95 to 0.99 Å) and were included in the refinement in the riding model approximation, with U(H) set to 1.2 times U eq (C). The amino H-atoms were located in a difference Fourier map, and were refined isotropically with a distance restraint of N-H 0.88±0.01 Å. Fig. 1. Anisotropic displacement ellipsoid plot (Barbour, 2001) of SnCl 3 (C 8 H 9 )(C 3 H 4 N 2 ) 2 at the 70% probability level; hydrogen atoms are drawn as spheres of arbitrary radius.