Ag₄₄(EBT)₂₆(TPP)₄ Nanoclusters With Tailored Molecular and Electronic Structure

Abstract

Although atomically precise metalloid nanoclusters (NCs) of identical sizew ith distinctly different molecular structures are highly desirable to understand the structural effects on the optical and photophysical properties,t heir synthesis remains highly challenging.H erein, we employed phosphine and thiol capping ligands featuring appropriate steric effects and synthesized acharge-neutral Ag NC with the formula Ag 44 (EBT) 26 (TPP) 4 (EBT:2-ethylbenzenethiolate; TPP:t riphenylphosphine). The single-crystal X-rays tructure reveals that this NC has ahollowmetal core of Ag 12 @Ag 20 and am etal-ligand shell of Ag 12 (EBT) 26 (TPP) 4 .T he presence of mixed ligands and long V-shaped metal-ligand motifs on this NC has resulted in an enhancement of the NIR-II photoluminescence quantum yield by > 25-fold compared to an allthiolate-stabilized anionic [Ag 44 (SR) 30 ] 4À NC (SR:t hiolate). Time-dependent density-functional calculations showt hat our Ag 44 NC is an 18-electron superatom with am odulated electronic structure as compared to the [Ag 44 (SR) 30 ] 4À anion, significantly influencing its optical properties.

Alkynyl and halogen co-protected (AuAg)44 nanoclusters: a comparative study on their optical absorbance, structure, and hydrogen evolution performance

“…As mentioned above, a similar M 12 @M 20 metal kernel has been documented in previous studies, including Ag 44 , 32,33 Au 12 Ag 32 , 33,34 and Au 12 Cu 32 35 NCs protected by thiolate ligands. The major difference between the thiolate-protected and alkynyl-protected M 44 (M = Au/Ag/Cu) NCs is observed in the outmost shell.…”

“…In the thiolate clusters, two of the peri-pheral 12 metal atoms bond with 5 thiolate ligands to form a total of six M 2 (SR) 5 staple motifs. [32][33][34][35] Furthermore, each staple motif unit connects with six edges on the dodecahedral M 20 shell to fully protect the metal clusters. In sharp contrast, the surface bonding motifs are totally different in the alkynyl protected (AuAg) 44 NCs in this study.…”

Ag44(EBT)26(TPP)4 Nanoclusters With Tailored Molecular and Electronic Structure

“…TheS CXRD analysis of as uitable single-crystal reveals that the synthesized NC consists of 44 Ag atoms and 26 EBT and four TPP ligands (Figure 1). [25] No counterions are located in the molecular structure,i ndicating that its electronic charge is zero.T hus,t he chemical formula of the NCs determined through the SCXRD is Ag 44 (EBT) 26 (TPP) 4 .T he number of metal atoms and ligands is identical to that of an all-thiolate-protected Ag NC of [Ag 44 (SR) 30 ] 4À , [23b] wherein four thiolates of [Ag 44 (SR) 30 ] 4À are substituted by four phosphines and the 4-charge is switched to zero.The packing structure shows that its unit cell accommodates two NCs ( Figure S3) in contrast to one NC in the unit cell of [Ag 44 (SPhF 2 ) 30 ] 4À with four counterions. [23b] TheAg 44 (EBT) 26 -(TPP) 4 NC is found to crystallize in at riclinic system with aspace group of P " 1(Table S1 in Supporting Information).…”

Ultrasmall Luminescent Metal Nanoparticles: Surface Engineering Strategies for Biological Targeting and Imaging

“…Ultrasmall luminescent metal nanoparticles (ULMNPs, mainly including Au, [ 1 , 2 , 3 , 4 , 5 ] Ag, [ 6 , 7 , 8 , 9 , 10 ] and Cu [ 11 , 12 , 13 , 14 , 15 ] ) are typically classified as atomically precise metal nanoclusters and metal nanoparticles with core sizes below ≈3 nm. The quantum confinement effect begins to appear, and the optical and electronic properties are typically dominated by electrons in discrete energy levels, such as semiconductor quantum dots (QDs), [ 16 ] which are different from the delocalized electrons observed in plasmonic metal nanoparticles (PMNPs).…”