title: Phosphonioalkylthiosulfate zwitterions--new masked thiol ligands for the formation of cationic functionalised gold nanoparticles.
abstract: We report the synthesis and structural characterisation of a new family of stable phosphonioalkylthiosulfate zwitterions, R3P+ (CH2)nS2O3- (R = Ph or Bu, n = 3,4,6, 8 or 10) which behave as cationic masked thiolate ligands with applications in the functionalisation of gold nanoparticles, having potential as new diagnostic biorecognition systems. The ligands were prepared by treatment of omega-bromoalkylphosphonium salts with sodium thiosulfate. The crystal and molecular structures of the zwitterions (R = Ph, n = 3) and (R = Bu, n = 3) were determined. A series of phosphonioalkanethiolate-capped gold nanoparticles dispersed in water was prepared by borohydride reduction of potassium tetrachloroaurate in the presence of the zwitterions in a dichloromethane-water system. UV-visible spectroscopy and scanning transmission electron-microscopy indicated that capped nanoparticles of ca. 5 nm diameter were present.
authors.affiliation: Biomedical Research Centre, Sheffield Hallam University, Howard St., Sheffield, UK S1 1WB.
authors.forename: Yon
authors.initials: Y
authors.lastname: Ju-Nam
authors.forename: Neil
authors.initials: N
authors.lastname: Bricklebank
authors.forename: David W
authors.initials: DW
authors.lastname: Allen
authors.forename: Philip H E
authors.initials: PH
authors.lastname: Gardiner
authors.forename: Mark E
authors.initials: ME
authors.lastname: Light
authors.forename: Michael B
authors.initials: MB
authors.lastname: Hursthouse
mesh_terms: D018360:Crystallography, X-Ray; D006046:Gold / Q000737:chemistry*; D006860:Hydrogen Bonding; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D017348:Microscopy, Electron, Scanning Transmission; D009943:Organophosphorus Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013439:Sulfhydryl Reagents / Q000138:chemical synthesis / Q000737:chemistry*; D013463:Sulfuric Acid Esters / Q000138:chemical synthesis / Q000737:chemistry
chemical_list: D009943:Organophosphorus Compounds; D013439:Sulfhydryl Reagents; D013463:Sulfuric Acid Esters; D006046:Gold