Thiolates thermolysis

Scheme 1. The solvent-free controlled thermolysis of gold(I) thiolate complex producing gold nanoparticles stabilized by alkyl groups derived from the precursor.

Scheme 2. Production of size-regulated gold nanoparticles stabilized by primary amines, tertiary amines, sulfides, and thiols formed by the controlled thermolysis of gold(I) thiolate complex in the presence of amine (reprinted from Ref. [11], 2005, with permission from Elsevier).

Betaines 261 are stable crystalline compounds. Knowledge of their chemical reactions is still limited. Alkaline hydrolysis of aryl derivatives (261 R = Ar) gives the 2-azobenzoic acids 266 but the mechanism of this rearrangement is unknown. Reduction by tin and hydrochloric acid gives the hydrazides 267. Thermolysis of the p-tolyl compound (261 R = p-MeC6H4) (120 C at 0.1 mm Hg) gives the isomeric triazine (268 R = >-MeC6H4). Phosphorus pentasulfide converts the 2-methyl derivative (261 R = Me) into 2-methyl l,2,3-benzotriazinium-4-thiolate (272 R = Me) (Section in,B,15). 

Much of this work has been directed towards materials-based applications, as volatile compounds might be CVD precursors see Chemical Vapor Deposition) and the ability of the thiolates and their fellows to react with the free chalcogens may assist doping lanthanide ions into optical and electrical materials. Thus, thermolysis of the [Ln(SePh)3(thf)3] (Ln =... 

Reports that thermolysis of metal chalcogenolate complexes offers a low-temperature route to the synthesis of novel solid state materials (32) is also stimulating research in this area. As is the case with copper(I) thiolates, lithium thiolates are often aggregated species (Section III.C) and from the few magnesium thiolate structures known (Section III.D) one sees a preference for monomeric and dimeric formulations when bulky substituents are present. 

In this part of the chapter we discuss (a) the controlled thermolysis of thiolate solutions in polystyrene matrix at temperatures above the polymer glass transition temperature and (b) the reaction mechanism in the case of silver-polystyrene nanocomposite systems. However, the same reaction mechanism is probably involved in the thermolysis of other mercaptide-polystyrene systems. This technique has proven to be an excellent new preparative scheme for the generation of both metal and sulfide clusters in polymers. In particular, high-molecular-weight n-alkanethiolates have shown to be the most effective compound class since the low volatility of thermolysis by-products avoids film foaming during the annealing process. 

Larsen, T. H., Sigman, M., Ghezelbash, A., Doty, R. C., and Korgel, B. A., Solventless synthesis of copper sulfide nanorods by thermolysis of a single source thiolate-derived precursor, J. Am. Chem. Soc.. 125,5638-5639 (2003). 

Several reports related to CdS nanocrystals incorporated in PS matrix have been reported in the literature [200-202]. Zhao et al. described preparation of small nanoparticles of CdS by a hydrothermal procedure in an aqueous solution that yields transparent CdS/PS nanocomposite films [200]. CdS/PS nanocomposites were also prepared successfully using in-situ thermolysis synthesis of a cadmium thiolate precursor dispersed in the polymer [201, 202]. The preparation of CdS/PS via a thermolysis method has several interesting advantages with respect to the common methods of precipitation for example, the CdS precursor is easy to prepare and is stable under normal conditions. The thermal and structural properties of CdS/PS nanocomposites also were broadly investigated [201,202]. 

---