Synthesis and characterisation of organotin(IV) derivatives of ambidentate ligands containing nitrogen and sulphur donor atoms

Abstract

A series of organotin(IV) derivatives of bis(pyrimidin-2-ylthio)methane ( ptm ), 1,2-bis(pyrimidin-2-ylthio)ethane ( pte ) and 1,6-bis(pyrimidin-2-ylthio)hexane ( pth ) have been prepared in dichloromethane at room temperature. The 2:1 (M/L) molar ratio compounds have a general formula of [Sn 2 Cl x Ph 8-x L] ( x = 2, 4, 6, 8; L = ptm , pte and pth ). A 1:1 complex was also obtained by reacting SnClPh 3 with pth . The organotin derivatives were characterised by multinuclear NMR ( 1 H, 13 C and 119 Sn) and infrared spectroscopy, gel permeation chromatography (GPC), microanalysis and melting point. In the triphenyltin derivatives, 1 , 5 , 9 and 10 the tin atoms show a distorted trigonal-bipyramidal confi guration where the ligand is monodentate towards the metal atom. In the compounds 2 -4 , 6 -8 and 11 -13 , the tin atoms each exhibit a distorted octahedral confi guration. Chelation is formed between the tin nucleus and the coordinating sulphur and nitrogen atoms. The correlation between the 1 J ( 13 C-119 Sn) and C-Sn-C bond angle indicates formation of 5-coordinate compounds.

Stereoselective Epimerizations of Glycosyl Thiols

“…The use of 119 Sn NMR spectroscopy proved diagnostic for probing the interaction of SnCl 4 with 3β in dichloromethane. There was a peak at δ −149 ppm in the proton decoupled 119 Sn NMR spectrum for free SnCl 4 (0.9 M solution in CDCl 3 ), whereas on addition of 3β the colorless solution became a brick red color and the 119 Sn peak shifted to −188.9 ppm, consistent with formation of a hexavalent tin complex in solution . This proposal was supported by 1 H and 13 C NMR analysis of the mixture generated after 3α (0.068 mmol) was dissolved in CDCl 3 (0.75 mL) and 2 equiv of SnCl 4 was added (from a solution in CDCl 3 ), which provided information on the complex formed between 3β and SnCl 4 ( 3β-SnCl 4 ).…”

Organotin(IV) Dithiocarbamate Complexes: Chemistry and Biological Activity

“…Chemical shifts (δ) in the range of −600 to −700nm suggest either 6- or 7-coordination geometry around the tin center. This has been attributed to a possible chemical equilibrium between octahedral and pentagonal-bypiramidal arrangement due to intramolecular metal ligand bond [ 74 ].…”

The Coordination Chemistry in the Antifungal Effect of Tin(IV)-Bis(Pyrimidin-2-Ylthio)Alkane Derivatives

“…The bis(pyrimidin-2-ylthio)alkanes and the organotin(IV) derivatives were prepared and characterized by our research group [27,28]. These compounds have the tin(IV) atom at the center of an octahedron as well as a trigonal bipyramidal arrangement., The pyrimidin-2-ylthioalkanes are coordinated by the monodentate, bridging bidentate and bridging tetradentate modes as shown in Fig.…”

“…A number of octahedral first-row transition metal complexes are recognized to show antifungal activity [26]. Considering that the Zn(II)-and Mn(II)-sulfur are typical bonds of the marketable fungicides Zineb (Zinc ethane-1,2-diylbis(dithiocarbamate) and Maneb (Manganese ethylene-1,2-bisdithiocarbamate), the tin(IV)-sulfur bond in complex-6 (see Fig.2) reinforces its antifungal activity, but the toxic effect of this compound is probably due to by-products from decomposition in solution [27]. On the other hand, the tin(IV)-sulfur bond is not present in the active complexes 1, 2, 5, 9 and 10 (see Fig.2) according to the infrared spectroscopy [27].…”