Preparation Of Helical Metal Nanotubes Using Chiral Amphiphiles

Chiral metal nanoparticles have received much interest since the first report on chiralglutathione-protected gold nanoparticles. The formation of these chiral particles has beenproposed to originate from their chiral core, chiral surfaces or chiral arrangement ofnanoparticles. Chiral low-molecular weight amphiphiles (LMWAs) can self-assemble intochiral nanostructures such as helical nanofibers and twisted/coiled nanoribbons. Thesechiral nanostructures can then be transcripted to nanomaterials. Morphologies of Ptnanostructures have usually been controlled using cationic surfactants, and nanoparticlesand nanowires have been obtained. Straight Pt nanotubes have been prepared usingone-dimensional nanocrystals as templates. However, reports on other morphologies arerare.Herein, a series of chiral LMWAs have been synthesized, including LL-12Val8PyBr，DD-12Val8PyBr, LL-12Val8PyClO4, DD-12Val8PyClO4, L-18Val8PyClO4, D-18Val8PyClO4which were characterized using NMR, IR, elemental analysis and circular dichroism (CD).Then, optically active single-handed helical Pt nanotubes were prepared using these chiralLMWAs self-assemblies as the templates. The morphology of the nanostructures observedby scanning electron microscopy (SEM) and transmission electron microscopy (TEM), CDindicated that Pt nanotubes were optical activity. We studied the influence of the reactionconditions on the results. Moreover, asymmetric catalysis behaviuor was studied. The othernanostructures of Pd, Au, Ag were also controlled using the self-assemblies of LL-andDD-12Val11PyBr as the templates. They were characterized using SEM, TEM, CD. Thesenanomaterials have potential applications in asymmetric catalysis and chirality sensor.