Synthesis, properties and selected applications of some sulfur containing organic compounds

Abstract

This work involves sulfur-containing compounds and consists of three studies: 1) Preparation of a sulfur-containing compound, 2-cyano-2-(hydroxyimino)-dithioacetic acid, by a thionation reaction; 2) The secondary interactions (hydrogen bonding) of three imidazole-2-thione derivatives and their aggregation behaviour in solution, the solid state and over polycrystalline gold surface; 3) Synthesis of L-cysteinate-intercalated CaAl-layered double hydroxide (LDH) and study on the interlamellar selective oxidation process of the intercalated L-cysteinate. Chapter 1 contains a few personal reflections as well as a brief statement of the research and aims of the thesis. Chapter 2 of the thesis deals with an entire overview on organosulfur compounds from basic concepts, properties, applications to synthetic methodologies. Contents on thiocarbonyl compounds are also specially emphasized. Next, a brief introduction on imidazole-2-thione derivatives as well as the secondary interactions between these molecules and their self-assembly capacities is described. A concise description on LDHs is also found at the end of chapter. Results of the work including synthesis of 2-cyano-2-(hydroxyimino)-dithioacetic acid; analysis of the secondary interactions (hydrogen bonding) as well as the aggregation behavior of three imidazole-2-thione derivatives in solution, the solid state and over polycrystalline gold surface are reported and discussed in chapter 3. Chapter 3 also includes results on preparation of L-cysteinate-intercalated LDH and examination of selective oxidation of the intercalated cysteinate anions. The first work is an attempt to develop a convenient three-step process for preparation of a ligand in which a thionation reaction is the key step. In the next step, complexation of the resultant ligand with Co(II), Ni(II), Cu(II) ions is scouted. Structural characterization of the intermediates and the ligand were accomplished. In addition, an independent study on the secondary interactions (hydrogen bonding) and self-assembly capacities of three imidazole-2-thione derivatives is also carried out and reported. The work is proceded with results on the synthesis of L-cysteinate-intercalated CaAl-LDH, its structural elucidation and evaluation of selectivity of interlamellar oxidation of the intercalated cysteinate anion to cystinate in aqueous and cysteinate sulfenic acid in acetone. In chapter 4, concluding remarks of the research are summarized. Finally, entire details about experimental work of the thesis including materials, instruments and analytical techniques employed, recipes for preparation of intermediates, ligand and complexes, procedures for synthesis of LDH, the intercalation and oxidation reactions are represented in chapter 5.