Synthesis And Photocatalytic Property Of Gold Nanoparticles By Using A Series Of Bolaform Amphiphiles

The gold nanoparticle, a kind of famous material in recent years, has goodbiocompatibility and optical properties, which can be used in the fields like biomedicine,sensing, catalysis and other else.As mentioned in previous reports, a variety of preparationmethods and many different kinds of capping agents have been explored to preparefunctionalized gold nanoparticles with tailored properties.The capacity to control size,shape and surface functionalization to yield certain surface properties as well as to be able tomanipulate the colloid stability of nanoparticle dispersions are important issues related totheir practical applications. Bolaamphiphiles, consisting of two polar functionalheadgroups that are linked covalently by one or more hydrophobic hydrocarbon chains,have been also attracting considerable attention in recent years.In this paper, we report the synthesis of four bolaform Schiff base amphiphiles withhydrophilic ethyleneamine spacers and aromatic headgroups.we also report the synthesis oftwo bolaform cholesteryl imide derivatives with different lengths of ethyleneaminespacers.We designed and utilized these bolaform amphiphiles for the following reasons.Firstly, although the effect of the hydrophilic spacers in gemini amphiphiles on the goldnanoprisms has been clarified in the report work, the exact behavior of the linker/spacer inthe synthesis of gold nanoparticles at a liquid-liquid interface still remains unclear.Secondly, the selection of different headgroups, such as phenyl，naphthyl and cholesterylmoieties with π-π stacking and large spatial hindrance, may cause some special features inorganized structures. By stirring the aqueous solution containing AuCl₄^-ions with thechloroform solution of bolaform amphiphile, AuCl₄^-ions were transferred into the organicphase and reduced to gold nanoparticles by amino group. Spectral and morphologicalmeasurements indicated that these bolaform amphiphiles could serve as both capping andreducing agents. Different gold nanostructures can be obtained depending on the differentspacers, headgroups of bolaform amphiphiles and the molar ratios of amphiphile to AuCl₄^-ions. The photocatalytic properties of as-made gold nanoparticles on the degradation ofmethyl orange indicated the headgroups and spacers in the amphiphiles played an importantrole in regulating the catalytic behaviors. The present work gave an original investigation ofsynthesis and regulation of gold nanostructures by utilizing bolaform amphiphiles with different substituted headgroups and spacers.