Thiolate oligomers

In order to increase the yield of the thiolate we carried the reaction published by Wayne in water instead of ethanol. We also increased the amount of thiourea by a factor of 2.5 to 3.0 times. This procedure allowed us to prevent the reaction between the unreacted chloride and the formed thiolate. By doing so we managed to increase the yield of the thiolate oligomers from 50% to about 85%. 

The solubility of these oligomers is important for their practical use in medicine. In the 1 1 reactions, the nature of the thiolate is important since the solubility of the resulting oligomer is affected by substituents on the thiolate moiety. Polar groups... 

Polymer formation is still observed with some sterically hindered thiolates, 2,4,6-Ao-propyl thiophenolate, and 2,4,6-trimethyl thiophenolate complexes have been studied. They can be synthesized by the reaction of Zn[N(SiMe3)2]2 with the appropriate arene chalcogenol. With the least steric bulk, the trimethyl derivative forms coordination polymers that can only be dissolved in strongly coordinating solvents. The iso-propyl derivative is more soluble forming oligomers in solution. 1... 

To arrange AuNPs into a monolayer, Simon and coworkers [74] reported a simple protocol via the oligonucleotides complementary immobiUzation. 5 -Amino-modified oligonucleotide was immobilized on the substrate surface first, and then, 15 nm gold particles modified with thiolated DNA oligomers were coupled to the surface through DNA base pairing. The resulted nanoparticle monolayers were demonstrated to have a thermally activated conductivity. A similar approach has been used to insert a liposome into a DNA chip [75] (Fig. lib). 

Boyer et al.(C. Boyer, J.J. Robin, B. Boutevin, unpublished results) used the nucleophilic addition of thiolate onto the double bond of alkyl (meth)acrylate to obtain monodispersed telechelic oligomers. This method is based on the nucleophilic character of the thiolate ion in the presence of a monomer carrying two acrylate or methacrylate functions to obtain the corresponding telechelic oligomers. The nucleophilic addition of the thiolate ion onto the double bond is quantitative (Scheme 4). 

Gold thiolate complexes, 88, are widely used in the treatment of rheumatoid arthritis . These complexes have AuS2 coordination environments and form oligomers " (AuSR) . 

Thiolated polymers, also termed thiomers, are conventional mucoadhesive polymers chemically modified to contain a cysteine residue in the polymer chain and thus establish covalent disulfide bonds with mucin." They can be manufactured to be either cationic (mostly thiolated chitosans) or anionic (carboxylic acid-containing polymers) however, their mucoadhesive extent will mostly be determined by their capacity to covalently bind to mucin. The polypeptide backbone of mucin can be divided into three major subunits tandem repeat array, carboxyl-, and amino-terminal domains. While the amino-terminal domain contains some of the cysteine residues, the carboxyl-terminal domain contains more than 10% of the cysteine residues. These cysteine-rich regions are responsible for forming the large mucin oligomers and ultimately, the groups that allow for the covalent mucoadhesive bond formation with oral mucosal systems." ... 

Lee, C.-Y., Canavan, H.E., Gamble, L.J., Castner, D. (2005) Evidence of impurities in thiolated single-stranded DNA oligomers and their effect on DNA self-assembly on gold. Langmuir, 21,5134-5141. 

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