We report the controlled growth of Au25（SR）18 and Au38（SR）24 （where R = CH2CH2Ph） nanoclusters of molecular purity via size-focusing from the same crude product that contains a distribution of nanoclusters. In t...We report the controlled growth of Au25（SR）18 and Au38（SR）24 （where R = CH2CH2Ph） nanoclusters of molecular purity via size-focusing from the same crude product that contains a distribution of nanoclusters. In this method, gold salt was first mixed with tetraoctylammonium bromide （TOAB）, and then reacted with excess thiol to form Au（I）-SR polymers in THF （as opposed to toluene in previous work）, followed by NaBH4 reduction. The resultant crude product contains polydisperse nanoclusters and was then used as the common starting material for controlled growth of Au25（SR）18 and Au38（SR）24, respectively. In Route I, Au25（SR）18 nanoclusters of molecular purify were produced from the crude product alter 6 h aging at room temperature. In Route II, the crude product was isolated and further subjected to thermal thiol etching in a toluene solution containing excess thiol, and one obtained pure Au38（SR）24 nanoclusters, instead of Au25（SR）Is. This work not only provides a robust and simple method to prepare both Au25（SR）18 and Au3s（SR）24 nanoclusters, but also reveals that these two nanoclusters require different environments for the size-focusing growth process.展开更多
We report herein a class of superatomic AU13 clusters stabilized by different N-heterocyclic carbenes(NHCs).The clusters show diverse metal surface structures,properties and functions as exemplified by:(1)the first an...We report herein a class of superatomic AU13 clusters stabilized by different N-heterocyclic carbenes(NHCs).The clusters show diverse metal surface structures,properties and functions as exemplified by:(1)the first anionic AU13 cluster[Au1g(NHC-1)sBr6],which has bulky NHC-1 ligands that lead to a rather open metal surface contributing to its high catalytic activity;(2)the tricationic cluster[Au13(NHC-2)sBr2]+which has bidentate,benzyl-rich NHC-2 ligands that make it ultra-stable and highly-luminescent,suitable for bio-imaging;and(3)by bearing two pyridyl groups on NHC-3,the dicationic cluster[Au:a(NHC-3)gClg]f+exhibits reversible and stable visible absorption and solubility responses to protonation/deprotonation cycles,making it a potential pH sensor(NHC-1=1,3-disopropylbenzimidazolin-ylidene;NHC-2=1,3-bis(1-benzyl-1H-benzimidazol-1-ium-yl)propane;NHC-3=1,3-bis(icolyI)benzimidazolin-ylidene).The study nicely demonstrates the importance of ligands in designing metal nanoclusters with desired functionalities.展开更多
We reported the synthesis ofAul3o（SPh-Br）50（Br-Ph-SH=4-bromothiophenol） nanocluster with high purity and high yield via ＂size focusing＂ and ＂ligand exchange＂ processes. The time of synthetic process was signif...We reported the synthesis ofAul3o（SPh-Br）50（Br-Ph-SH=4-bromothiophenol） nanocluster with high purity and high yield via ＂size focusing＂ and ＂ligand exchange＂ processes. The time of synthetic process was significantly reduced compared with previous synthetic routine. AU130（SPh-Br）50 was determined by UV-Vis absorption spectros- copy and matrix-assisted laser desorption ionization（MALDI） mass spectroscopy. Thermo-gravimetric analysis （TGA） and size-exclusion chromatogram（SEC） analyses confirmed the purity of AU130（SPh-Br）50. The yield of gold nanoc- lusters was 20%（based on HAuCl4）.展开更多
基金supported by the Air Force Office of Scientific Research under AFOSR Award (FA9550-11-1-9999, FA9550-11-1-0147)the Camille Dreyfus Teacher-Scholar Awards Programsupport by the China Scholarship Council (CSC)
文摘We report the controlled growth of Au25（SR）18 and Au38（SR）24 （where R = CH2CH2Ph） nanoclusters of molecular purity via size-focusing from the same crude product that contains a distribution of nanoclusters. In this method, gold salt was first mixed with tetraoctylammonium bromide （TOAB）, and then reacted with excess thiol to form Au（I）-SR polymers in THF （as opposed to toluene in previous work）, followed by NaBH4 reduction. The resultant crude product contains polydisperse nanoclusters and was then used as the common starting material for controlled growth of Au25（SR）18 and Au38（SR）24, respectively. In Route I, Au25（SR）18 nanoclusters of molecular purify were produced from the crude product alter 6 h aging at room temperature. In Route II, the crude product was isolated and further subjected to thermal thiol etching in a toluene solution containing excess thiol, and one obtained pure Au38（SR）24 nanoclusters, instead of Au25（SR）Is. This work not only provides a robust and simple method to prepare both Au25（SR）18 and Au3s（SR）24 nanoclusters, but also reveals that these two nanoclusters require different environments for the size-focusing growth process.
基金the National Key R&D Program of China(No.2017YFA0207304)the National Nautural Science Foundation of China(Nos.21890752,21731005,21802109,and 21721001)the fundamental research funds for central universities(No.20720190043)for financial support.
文摘We report herein a class of superatomic AU13 clusters stabilized by different N-heterocyclic carbenes(NHCs).The clusters show diverse metal surface structures,properties and functions as exemplified by:(1)the first anionic AU13 cluster[Au1g(NHC-1)sBr6],which has bulky NHC-1 ligands that lead to a rather open metal surface contributing to its high catalytic activity;(2)the tricationic cluster[Au13(NHC-2)sBr2]+which has bidentate,benzyl-rich NHC-2 ligands that make it ultra-stable and highly-luminescent,suitable for bio-imaging;and(3)by bearing two pyridyl groups on NHC-3,the dicationic cluster[Au:a(NHC-3)gClg]f+exhibits reversible and stable visible absorption and solubility responses to protonation/deprotonation cycles,making it a potential pH sensor(NHC-1=1,3-disopropylbenzimidazolin-ylidene;NHC-2=1,3-bis(1-benzyl-1H-benzimidazol-1-ium-yl)propane;NHC-3=1,3-bis(icolyI)benzimidazolin-ylidene).The study nicely demonstrates the importance of ligands in designing metal nanoclusters with desired functionalities.
基金Projects(82073604, 81903369) supported by the National Natural Science Foundation of ChinaProject(S202010555075) supported by the National Innovation Training Program for College Students,ChinaProject (CX20210962) supported by the Postgraduate Research and Innovation Project of Hunan Province,China。
文摘We reported the synthesis ofAul3o（SPh-Br）50（Br-Ph-SH=4-bromothiophenol） nanocluster with high purity and high yield via ＂size focusing＂ and ＂ligand exchange＂ processes. The time of synthetic process was significantly reduced compared with previous synthetic routine. AU130（SPh-Br）50 was determined by UV-Vis absorption spectros- copy and matrix-assisted laser desorption ionization（MALDI） mass spectroscopy. Thermo-gravimetric analysis （TGA） and size-exclusion chromatogram（SEC） analyses confirmed the purity of AU130（SPh-Br）50. The yield of gold nanoc- lusters was 20%（based on HAuCl4）.
