Synthesis, Stabilization, Functionalization and, DFT Calculations of GoldNanoparticles in Fluorous Phases (PTFE and Ionic Liquids)

摘要

Gold nanoparticles (Au-NPs)were reproducibly obtained by thermal,photolytic, or microwave-assisted de-composition/reduction under argonfrom Au(CO)C1 or KAuC14 in the pres-ence of n-butylimidazol dispersed inthe ionic liquids (ILs) BMIm+13F4,BMIm+0Tf-, or BtMA+NTf2-(BMIm+=n-butylmethylimidazolium,BtMAn-butyltrimethylammonium,OTf03SCF3, NTf,N-(02SCF3)2). The ultra small and uni-form nanoparticles of about 1-2 nm di-ameter were produced in BMIm+BF,-and increased in size with the molecu-lar volume of the ionic liquid anion usedinBMIrn+0Tf-andBtMA+NTf2-. Under argon the Au-NP/IL dispersion is stable without anyadditional stabilizers or capping mole-cules. From the ionic liquids, the goldnanoparticles can be functionalizedwith organic thiol ligands, transferred,and stabilized in different polar andnonpolar organic solvents. Au-NPs canalso be brought onto and stabilized byinteraction with a polytetrafluoroethy-lene (PTFE, Teflon) surface. Densityfunctional theory (DFT) calculationsfavor interactions between IL anionsinstead of IL cations. This suggests aAuF interaction and anionic Au,, sta-bilization in fluorine-containing ILs.The 19F NMR signal in BMIm+13F4shows a small Au-NP concentration-de-pendent shift. Characterization of thedispersed and deposited gold nanopar-ticles was done by transmission elec-tron microscopy (TEM/HRTEM),transmission electron diffraction(TED), dynamic light scattering(DLS), UV/Vis absorbance spectrosco-py, scanning electron microscopy(SEM), electron spin resonance (ESR),and electron probe micro analyses(EPM, SEM/EDX).