Synthesis, Structural Characterization, and Biological Studies of Six- and Five-Coordinate Organotin(IV) Complexes with the Thioamides 2-Mercaptobenzothiazole, 5-Chloro-2-mercaptobenzothiazole, and 2-Mercaptobenzoxazole

Organotin(IV) complexes with the formulas [(C6H5)3Sn(mbzt)] (1), [(C6H5)3Sn(cmbzt)] (3), and [(C6H5)2Sn(cmbzt)2]
(4) (Hmbzt = 2-mercaptobenzothiazole and Hcmbzt = 5-chloro-2-mercaptobenzothiazole) have been synthesized
and characterized by elemental analysis; FT-IR, Raman, 1H, 13C, and 119Sn NMR, and Mössbauer spectroscopic
techniques; and X-ray crystallography at various temperatures. The crystal structures of complexes 1, 3, and 4
were determined by X-ray diffraction at room temperature [295(1) or 293(2) K]. The complexes [(C6H5)3Sn(mbzo)]
(2) and [(n-C4H9)2Sn(cmbzt)2] (5) (Hmbzo = 2-mercaptobenzoxazole) were synthesized by new improved methods,
and their structures were determined at low temperature [100(1) K] and compared to those solved at room
temperature. Comparison with {(CH3)2Sn(cmbzt)2]} (6), already reported, was also attempted. The influence of
temperature on the geometry of the complexes is discussed. In the cases of complexes 1−3, three carbon atoms
from phenyl groups and one sulfur atom and one nitrogen atom from thione ligands form a tetrahedrally distorted
trigonal-bipyramidal geometry around the five-coordinate tin(IV) ion. In complexes 4−6, two carbon atoms from aryl
groups and two sulfur atoms and two nitrogen atoms from thione ligands form a distorted tetrahedral geometry,
tending toward octahedral, around the six-coordinate tin(IV) ions, with trans-C2, cis-N2, and cis-S2 configurations.
Although the C−Sn and S−Sn bond distances are found to be constant in compounds 1−6, their N−Sn bond
lengths vary significantly (from 2.635 to 3.078 Å), with the longer distances found in the cases of five-coordinate
complexes 1−3.