Complexes of dimethyldihalotin(IV) with imidazole and pyrazole: the crystal structure of dibromobis(pyrazole)dimethyltin(IV)

• Published in: Journal of organometallic chemistry Vol. 338; no. 2; pp. 187 - 193
• Main Authors: Alberte, B., González, A.Sánchez, García, E., Casas, J.S., Sordo, J., Castellano, E.E.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 12.01.1988
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/0022-328X(88)80501-1

A series of neutral adducts of dimethyltin(IV) dihalides of general formula Me 2SnX 2L 2 (where L = imidazole, pyrazole) has been prepared. The structure of the complex dibromobis(pyrazole)dimethyltin(IV) has been determined by X-ray diffraction. (Crystal data: Br 2C 8H 14N 4Sn, M = 444.7; orthorhombic, Pbca, a 7.644(1), b 13.955(7), c 26.249(4) Å, V 2800(2) Å 3, Z = 8, R = 0.041). The compound consists of discrete trans-SnMe 2Br 2(HPz) 2 units with the metal atom octahedrally coordinated to two Br atoms (SnBr 2.703(2), 2.766(2) Å; BrSnBr 178.78(7)°), to two methyl carbons (both SnC 2.13(2) Å; CSnC 179.0(6)°), and to two pyrazole groups (SnN 2.34(1), 2.36(1) Å; NSnN 175.8(4)°). The dihedral angle between the two pyrazole rings is 8.9°. The IR data are consistent with this trans-stereochemistry for all the complexes. The 1H NMR data indicate that the pyrazole compounds dissociate in DMSO- d 6 solution but in CDCl 3 solution the trans-configuration can be also present if an excess of the ligand is present.