Synthesis, characterization, and crystal structures of tin(IV) 1-pyrrolethiocarboxylates

Abstract

Tin 1-pyrrolecarbothioates (1-pyrrolethiocarboxylates) SnR_4–nL_n(L = OSC[graphic omitted]H, n= 1–4) have been synthesized and characterized by i.r., n.m.r. (¹H, ¹³C, and ¹¹⁹Sn), and ¹¹⁹Sn Mössbauer spectral studies. X-Ray crystal and molecular structure analyses were performed on the compounds SnPh₃L, SnMe₂L₂, SnPhL₃, and SnL₄. The triphenyltin complex is tetrahedral with a sulphur-bonded ligand. The bis complex can be considered to be essentially tetrahedral or as highly distorted octahedral if very weak Sn–O interactions (average bond length 2.65 Å) are taken into account. The phenyltin tris complex contains a seven-co-ordinated tin atom in a distorted pentagonal-bipyramidal environment with all the three ligands bound to the tin in an anisobidentate fashion (average Sn–O 2.506 Å). The complex SnL₄ shows a distorted-octahedral co-ordination geometry with two thiocarbamates functioning as bidentate chelates, the other two as monodentate ligands through the sulphur atom. In solution, these structures are essentially retained, as indicated by the n.m.r. spectral features.