title: Studies on the sulfation of cellulose α-lipoate and ability of the sulfated product to stabilize colloidal suspensions of gold nanoparticles.
abstract: A versatile method for the synthesis of cellulose α-lipoate with a low degree of substitution (DS) has been developed using N,N-dimethylacetamide (DMA)/LiCl as a solvent and N,N'-carbonyldiimidazole (CDI) as an esterification reagent. The cellulose α-lipoate with DS of α-lipoate groups of 0.26 was converted with sulfur trioxide-pyridine complex in dimethyl sulfoxide (DMSO) as solvent. The sulfation is accompanied by an unexpected partial oxidation of the disulfide moiety leading to the formation of the corresponding stereoisomers of S-oxides. The resulting mixture of water-soluble cellulose α- and β-lipoate sulfate possesses a DS of sulfuric acid half ester groups of 1.78. This cellulose-α/β-lipoate sulfate derivative can be used as an effective stabilizer and solubilizer for the formation of colloidal suspensions of gold nanoparticles formed in situ in aqueous solution.
authors.affiliation: Friedrich Schiller University of Jena, Institute for Organic Chemistry and Macromolecular Chemistry, Center of Excellence for Polysaccharide Research, Humboldtstraße 10, D-07743 Jena, Germany.
authors.forename: Velina
authors.initials: V
authors.lastname: Sarbova
authors.affiliation: Friedrich Schiller University of Jena, Institute for Organic Chemistry and Macromolecular Chemistry, Center of Excellence for Polysaccharide Research, Humboldtstraße 10, D-07743 Jena, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Koschella
authors.affiliation: University of Hull, Cottingham Road, Kingston Upon Hull HU6 7RX, UK.
authors.forename: Fei
authors.initials: F
authors.lastname: Cheng
authors.affiliation: University of Hull, Cottingham Road, Kingston Upon Hull HU6 7RX, UK.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Kelly
authors.affiliation: Friedrich Schiller University of Jena, Institute for Organic Chemistry and Macromolecular Chemistry, Center of Excellence for Polysaccharide Research, Humboldtstraße 10, D-07743 Jena, Germany. Electronic address: thomas.heinze@uni-jena.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Heinze
mesh_terms: D002482:Cellulose / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D003102:Colloids; D006046:Gold; D053768:Metal Nanoparticles / Q000737:chemistry*; D008063:Thioctic Acid / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D003102:Colloids; D008063:Thioctic Acid; D006046:Gold; D002482:Cellulose
keywords: Esterification of cellulose; Gold nanoparticles; Oxidation; Sulfur-containing cellulose derivatives; Water-solubility