Anhydrous Aluminum Chloride Catalyzed Methylene Group Inclusion: Mechanistic, Spectral and Single Crystal X-Ray Structural Study on Methanediyl Bis(Cyclohexylmethylcarbamodithioate)

Abstract

In this study anhydrous AlCl3 is used as a catalyst for the inclusion of a methylene group in to cyclohexylmethyldithiocarbamic acid to form methanediyl bis(cyclohexylmethylcarbamodithioate). Dichloromethane is used as a methylene group bearer in the reaction. A suitable mechanistic pathway involving +CH2Cl is discussed. FTIR, NMR and Mass spectral techniques have been used in the analysis. Single crystal X-ray structure of the compound was determined. FTIR spectrum of the compound showed υc-s band at 1073 cm-1 and υC-H vibrations appeared at 2853 and 2928 cm-1. Thioureide stretching band was observed at 1473 cm-1. The molecular ion peak in the Mass spectroscopy confirmed the proposed formula. H1 NMR spectrum of the compound showed a signal at 4.33(s) ppm for α-CH of the cyclohexyl ring and -CH3 protonsattached to nitrogen appeared at 3.40 ppm. Methylene proton (S-CH2-S) signal appeared at 3.16 ppm which is largely deshielded by the presence of two electronegative sulphur atoms on either side. The characteristic methylene carbon (S-CH2-S) signal appeared at 45.46 ppm in the 13C NMR spectrum. Single crystal X-ray structural analysis of the compound showed it to be monomeric. Methylene carbon in S-CH2-S, C(9) is tetrahedrally bonded to two hydrogen atoms and two sulphur atoms S(2), S(3). The molecule stacks its cyclohexyl rings along ‘c’ axis of the unit cell. Short contacts in the form of supramolecular interactions such as C---S and S---S exist in the solid state at 3.49 and 3.50 Å respectively.