The rod-shaped Au25 nanocluster possesses a low photoluminescence quantum yield (QY=0.1%) and hence is not of practical use in bioimaging related applications. Herein, we show that substituting silver atoms for gold the 25-atom matrix can drastically enhance photoluminescence. obtained Ag(x)Au(25-x) (x=1-13) nanoclusters exhibit high (QY=40.1%), which striking contrast with normally weakly luminescent species (x=1-12, QY=0.21%). X-ray crystallography further determines substitution sites Ag...

We report the crystal structure of a new nanocluster formulated as Au28(TBBT)20, where TBBT = 4-tert-butylbenzenethiolate. It exhibits rod-like Au20 kernel consisting two interpenetrating cuboctahedra. The is protected by four dimeric "staples" (-SR-Au-SR-Au-SR-) and eight bridging thiolates (-SR-). unit cell Au28(TBBT)20 single crystals contains pair enantiomers. origin chirality primarily rooted in rotating arrangement staples well (quasi-D2 symmetry). enantiomers were separated chiral...

We report single-atom doping of gold nanoclusters (NCs), and its drastic effects on the optical, electronic, catalytic properties, using 25-atom system as a model. In our synthetic approach, mixture Pt(1)Au(24)(SC(2)H(4)Ph)(18) Au(25)(SC(2)H(4)Ph)(18) was produced via size-focusing process, then NCs were obtained by selective decomposition in with concentrated H(2)O(2) followed purification size-exclusion chromatography. Experimental theoretical analyses confirmed that possesses Pt-centered...

We report the X-ray structure of a cyclohexanethiolate-capped [Au23(SR)16]− nanocluster (counterion: tetraoctylammonium, TOA+). The comprises cuboctahedron-based bipyramidal Au15 kernel, which is protected by two staple-like trimeric Au3(SR)4 motifs, monomeric Au(SR)2 and four plain bridging SR ligands. Electronic analysis reveals nonsuperatomic feature confirms kernel surface motifs. staple motif are unprecedented offer new insight in understanding evolution gold nanoclusters.

Understanding the isomerism phenomenon at nanoscale is a challenging task because of prerequisites precise composition and structural information on nanoparticles. Herein, we report ligand-induced, thermally reversible isomerization between two thiolate-protected 28-gold-atom nanoclusters, i.e. Au28(S-c-C6H11)20 (where -c-C6H11 = cyclohexyl) Au28(SPh-(t)Bu)20 -Ph-(t)Bu 4-tert-butylphenyl). The intriguing ligand effect in dictating stability Au28(SR)20 structures further investigated via...

Solving the total structures of gold nanoclusters is critical importance for understanding their electronic, optical and catalytic properties. Herein, we report X-ray structure a charge-neutral Au24(SCH2Ph-tBu)20 nanocluster. This features bi-tetrahedral Au8 kernel protected by four tetrameric staple-like motifs. Electronic analysis further carried out absorption spectrum interpreted. The Au24(SCH2Ph-tBu)20, Au23(S-c-C6H11)16 Au25(SCH2CH2Ph)18 constitute first crystallographically...

Controlling nanoparticles with atomic precision has long been a major dream of nanochemists. This first realized in the case gold nanoparticles. We previously discussed size-focusing methodology for syntheses atomically precise nanoclusters protected by thiolate ligands (referred to as Aun(SR)m, where n and m represent exact numbers atoms surface ligands). led molecularly pure such Au25(SR)18, Au38(SR)24, Au144(SR)60, many others recent work. In this Perspective article, we shall further...

Abstract Unravelling the atomic structures of small gold clusters is key to understanding origin metallic bonds and nucleation from organometallic precursors. Herein we report X‐ray crystal structure a charge‐neutral [Au 18 (SC 6 H 11 ) 14 ] cluster. This exhibits an unprecedented bi‐octahedral (or hexagonal close packing) Au 9 kernel protected by staple‐like motifs including one tetramer, dimer, three monomers. Until present, cluster smallest crystallographically characterized thiolates...

The [Au37(PPh3)10(SR)10X2]+ nanocluster (where SR = thiolate and X Cl/Br) was theoretically predicted in 2007, but since then, there has been no experimental success the synthesis structure determination. Herein, we report a kinetically controlled, selective of [Au37(PPh3)10(SC2H4Ph)10X2]+ (counterion: Cl– or Br–) with its crystal characterized by X-ray crystallography. This shows rod-like assembled from three icosahedral Au13 units linear fashion, consistent earlier prediction. optical...

We report the synthesis and total structure determination of a Au(24) nanocluster protected by mixed ligands phosphine thiolate. Single crystal X-ray crystallography electrospray ionization mass spectrometry (ESI-MS) unequivocally determined cluster formula to be [Au(24)(PPh(3))(10)(SC(2)H(4)Ph)(5)X(2)](+), where X = Cl and/or Br. The consists two incomplete (i.e., one vertex missing) icosahedral Au(12) units joined five thiolate linkages. This shows interesting differences from previously...

We report a method for heavy doping of the Au25(SR)18 nanocluster (where R = C6H11) with silver through Ag(I)-thiolate complex induced size/structure transformation Au23(SR)16(-) into Au25-xAgx(SR)18(-). X-ray crystallographic analysis revealed that Ag dopants are distributed not only in icosahedral core but also surface staple motifs; latter was achieved earlier studies alloy Au25-xAgx nanoclusters.

Because of the small size and large surface area thiolate-protected Au nanoclusters (NCs), protecting ligands are expected to play a substantial role in modulating structure properties, particularly solution phase. However, little is known on how thiolate explicitly modulate structural properties NCs at atomic level, even though this information critical for predicting performance application settings including as catalyst interacting with molecules sensor biomolecular systems. Here, we...

A versatile method for the design of colloidal crystals involves use DNA as a particle-directing ligand. With such systems, DNA-nanoparticle conjugates are considered programmable atom equivalents (PAEs), and rules have been devised to engineer crystallization outcomes. This work shows that when reduced in size grafting density, PAEs behave electron (EEs), roaming through stabilizing lattices defined by larger PAEs, electrons do metals classical picture. discovery defines new property...

Thiolato-protected gold nanoclusters have acquired wide applications; however, on the fundamental science end there is still a lack of deep understanding their high stability. Recent success in transforming highly robust biicosahedral Au38(SCH2CH2Ph)24 nanocluster into an extremely stable tetrahedral Au36(SPh-(t)Bu)24 raises important question: Is transformation due to bulkiness effect SPh-(t)Bu or electronic conjugation aromatic ligand as opposed nonaromatic SCH2CH2Ph? Toward this goal, we...

Abstract The rod‐shaped Au 25 nanocluster possesses a low photoluminescence quantum yield (QY=0.1 %) and hence is not of practical use in bioimaging related applications. Herein, we show that substituting silver atoms for gold the 25‐atom matrix can drastically enhance photoluminescence. obtained Ag x 25− ( =1–13) nanoclusters exhibit high (QY=40.1 %), which striking contrast with normally weakly luminescent species =1–12, QY=0.21 %). X‐ray crystallography further determines substitution...

This study describes the antimicrobial resistance temporal trends and seasonal variation of Escherichia coli (E. coli) urinary tract infections (UTIs) over five years, from 2009 to 2013, compares prevalence in hospital- community-acquired E. UTI. A cross sectional UTIs patients attending a tertiary referral hospital Canberra, Australia was undertaken. Time series analysis performed illustrate trends. Only first positive UTI per patient year included analysis. total 15,022 cultures 8724 were...

Abstract Unravelling the atomic structures of small gold clusters is key to understanding origin metallic bonds and nucleation from organometallic precursors. Herein we report X‐ray crystal structure a charge‐neutral [Au 18 (SC 6 H 11 ) 14 ] cluster. This exhibits an unprecedented bi‐octahedral (or hexagonal close packing) Au 9 kernel protected by staple‐like motifs including one tetramer, dimer, three monomers. Until present, cluster smallest crystallographically characterized thiolates...

The catalytic potential of atomically precise quantum-sized gold nanoclusters (Au38(SC2H4Ph)24) is explored for the three-component coupling an aldehyde, alkyne and amine to synthesize propargylamines. A high efficiency with a very low loading (0.01 mol%) achieved. Furthermore, synergistic effect electron-deficient surface (i.e. Auδ+, 0 < δ+ 1) electron-rich Au23 core ligand-protected critical this reaction.

We report the first example of a chiral mixed thiolate/stibine-protected gold cluster, formulated as Au18(S-Adm)8(SbPh3)4Br2 (where S-Adm = 1-adamantanethiolate). Single crystal X-ray crystallography reveals origin chirality in cluster to be introduction rotating arrangement Au2(S-Adm)3 and Au(S-Adm)2 staple motifs on an achiral Au13 core subsequent capping remaining atoms by SbPh3 Br- ligands. Interestingly, structure properties this new Au18 are found different from other reported clusters...

Abstract The biological properties of spherical nucleic acids (SNAs) are largely independent nanoparticle core identity but significantly affected by oligonucleotide surface density. Additionally, the payload‐to‐carrier (i.e., DNA‐to‐nanoparticle) mass ratio SNAs is inversely proportional to size. While with many types and sizes have been developed, all in vivo analyses SNA behavior limited cores &gt;10 nm diameter. However, “ultrasmall” constructs (&lt;10 diameter) can exhibit increased...

A trio of thiolate-protected atomically precise gold nanoclusters, [Au23(S-c-C6H11)16]–, Au24(SCH2pHtBu)20 and [Au25(SCH2CH2pH)18]–, are utilized as catalysts for 4-nitrophenol (4-NP) reduction to 4-aminophenol (4-AP). Despite nearly identical sizes (~1 nm), the three nanoclusters possess distinctly different atomic packing structures surface ligand binding modes, which contribute catalytic performance. The [Au23(S-c-C6H11)16]– nanocluster shows highest activity with a kinetic rate constant...

Poly-L-lysine (PLL) grafted ordered mesoporous material was prepared by a combination of NCA polymerization and click chemistry. Large pore SBA-15 with mesopore diameter ∼12 nm synthesized using previously reported method. The surface this modified azidopropyl groups. This "clickable" then reacted an alkyne terminated poly-L-lysine the ring-opening ε-cbz-L-lysine N-TMS propargylamine as initiator. procedure allows grafting uniform polymer film high loading. No appreciable blocking observed...