Crystal structure of the coordination compound of triiodidomethyltin(IV) with 2,2'-bi-pyridine, MeSnI3·bipy.

The title compound, (2,2'-bi-pyridine-κ(2) N,N')tri-iodido-meth-yltin(IV), [Sn(CH3)I3(C10H8N2)], crystallizing in the non-centrosymmetric ortho-rhom-bic space group Pca21 as an inversion twin, represents one of the few structurally characterized coordination compounds of an organotin(IV) trihalide with 2,2'-biypridine. Its distorted octa-hedral geometry shows a meridional arrangement of the I atoms and the methyl group is in-plane with the five-membered chelate ring. Asymmetric bonding of the biypridine ligand to the tin(IV) atom is reflected by different Sn-N bond lengths [2.268 (4) Å versus 2.293 (4) Å] and caused by the static trans effect of the methyl group. Sn-I bond lengths show some differences with respect to their orientation to the methyl group or the bi-pyridine ligand, respectively. Angular distortions in the coordination sphere of the Sn(IV) atom mainly arise from the large I atoms. Distortion of the 2,2'-bi-pyridine ligand as a result of its coordination to the Sn(IV) atom are described by the twisting angle of 2.5 (2)° between the least-squares planes of the two pyridine rings, as well as by the angle of 6.2 (2)° between the two lines through the pyridine-connecting C atoms and the para-orientated C atoms. Directional inter-molecular inter-actions are restricted to weak I⋯H van der Waals contacts.