Preparation and photocoagulation in chloroform of Au nanoparticles capped with azobenzene-derivatized alkanesulfides

Azobenzene-derivatized alkanesulfides di[10-(4-ethoxyphenylazo)-2-methyl-phenoxydecanyl] sulfide (2AM10)(2)S, and di[10-(4-octylphenylazo)-2-methyl-phenoxypentyl] sulfide (8AM5)(2)S, were synthesized and used to prepare capped Au nanoparticles. The conversion of photoisomerization (trans to cis) of these sulfides on Au nanoparticles dispersed in chloroform was 70-80%. Au nanoparticles capped with cis(2AM10)(2)S were found to coagulate in chloroform, while those capped with trans-(2AM10)(2)S dispersed in chloroform. However, Au nanoparticles capped with (8AM5)(2)S always formed a dispersion in chloroform regardless of whether (8AM5)(2)S was in the trans or cis conformation. (C) 2008 Elsevier B.V. All rights reserved.