Diphosphine-induced chiral propeller arrangement of gold nanoclusters for singlet oxygen photogeneration

摘要

In this study,1,2-bis(diphenylphosphino)ethane (dppe) ligands are used to synthesize gold nanoclusters with an icosahedral Au13 core.The nanoclusters are characterized and formulated as [Au13(dppe)5Cl2]Cl3 using synchrotron radiation X-ray diffraction,UV/Vis absorption spectroscopy,electrospray ionization mass spectrometry,and density functional theory (DFT) calculations.The bidentate feature of dppe ligands and the positions of coordinating surface gold atoms induce a helical arrangement that forms a propeller-like structure,which reduces the symmetry of the gold nanocluster to C1.Therefore,dppe ligands perform as a directing agent to create chiral an ansa metallamacrocycle [Au13(dppe)5Cl2]3+ nanocluster,as confirmed by simulated electronic circular dichroism spectrum.The highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap of the [Au13(dppe)sCl2]3+ cluster is determined as approx.1.9 eV,and further confirmed by ultraviolet photoemission spectroscopy analysis and DFT simulation.Furthermore,the photoactivity of [Au13(dppe)5Cl2]3+ is investigated,with the nanocluster shown to possess near-infrared photoluminescence properties,which can be employed for 1O2 photogeneration.The quantum yield of 1O2 photogeneration using the [Au13(dppe)5Cl2]3+ nanocluster is up to 0.71,which is considerably higher than those of anthracene (an organic dye),and Au25 and Au38 nanoclusters.