Surface functionalization: an efficient alternative for promoting the catalytic activity of closed shell gold clusters

Density functional theory calculations within the framework of generalized gradient approximation (GGA), meta-GGA, and local functionals were carried out to investigate the reactivity and catalytic activity of Ag n ( n = 15–20) clusters. Our results reveal that all the Ag n clusters in this size range, except Ag 20 , adsorb O 2 preferably in the bridged mode with enhanced binding energy as compared to the atop mode. The O 2 binding energies range from 0.77 to 0.29 in the bridged mode and from 0.36 to 0.15 eV in the atop mode of O 2 adsorption. The strong binding in the case of the bridged mode of O 2 adsorption is also reflected in the increase in O–O bond distance. Natural bond orbital charge analysis and vibrational frequency calculations reveal that enhanced charge transfer occurs to the O 2 molecule and there is significant red shift in the stretching frequency of O–O bond in the case of the bridged mode of O 2 adsorption on the clusters, thereby confirming the above results. Moreover, the simulated CO oxidation reaction pathways show that the oxidation of the CO molecule is highly facile on Ag 16 and Ag 18 clusters involving small kinetic barriers and higher heats toward CO 2 formation.

show abstract

“…TZVP types of basis sets have been widely used for interactions of small molecules with transition metals and clusters. 53 − 56 …”

Section: Computational Detailsmentioning

confidence: 99%

“…The LANL2DZ basis set and the corresponding Los Alamos relativistic effective core potential were used for the silver atoms, and the TZVP basis set was used for carbon and oxygen atoms. TZVP types of basis sets have been widely used for interactions of small molecules with transition metals and clusters. − …”

Section: Computational Detailsmentioning

confidence: 99%

Probing the Site-Specific Reactivity and Catalytic Activity of Ag_n (n = 15–20) Silver Clusters

et al. 2022

Self Cite

View full text Add to dashboard Cite

show abstract

“…The fluorescent gold nanoclusters have attracted great interest and exhibit prospective potential in bioimaging and biocatalytic treatment. ,,,− To date, multiple fluorescent gold nanoclusters have been developed for bioimaging such as Au 25 , Au 38 , and Au 22 . ,− The gold nanoclusters present excellent biocompatibility and water solubility on account of proper surface ligands and ultrasmall size, which is typically below 5 nm, less than the threshold of renal clearance, and reveal promise for clinical translation. ,,− The fluorescent gold nanoclusters show discrete energy levels and molecule-like properties in absorption and fluorescence features as a result of quantum confinement. − Both the Au core and the charge transfer states incorporating the surface ligands contribute to their fluorescence emission. Metal doping has shown the ability to promote the brightness and QY of the gold nanoclusters, , and ligands also have remarkable influences on the fluorescence properties while the understanding is far from completed. ,,− Thus, elucidating the interaction of the Au core and surface ligands and finding the regularity influence of the ligands on optical properties may accelerate the research and development of gold nanoclusters for bioimaging.…”

Section: Introductionmentioning

confidence: 99%

Ligand Engineering of Gold Nanoclusters for NIR-II Imaging

Guo,

Zhang,

Zhao

et al. 2023

ACS Appl. Nano Mater.

View full text Add to dashboard Cite

Near-infrared-II (NIR-II) imaging has shown great potential in medical diagnosis and surgical navigation, but developing safe, photostable, high-brightness molecular probes remains a great challenge. Due to their ultrasmall size resulting in highly efficient renal clearance, gold nanoclusters have shown great clinical potential. In this work, we systematically explored the effect of different ligands on the luminescence and bioactivity of gold nanoclusters. Our results show that gold nanoclusters protected by thioglycolic acid (TGA) and 6-mercaptohexanoic acid (MHA) exhibit the strongest fluorescence, while 3mercaptopropionic acid (MPA)-and sodium sulfide (Na 2 S)-protected gold nanoclusters show the weakest NIR-II signal. Further doping showed that the Cd-doped MPA and MHA-protected gold nanoclusters exhibited enhanced fluorescence, but the cysteine (Cys)-, glutathione (GSH)-, and Na 2 S-protected gold nanoclusters showed fluorescence quenching after doping, indicating significant ligand selectivity. Because of the unique multi-energy structure and the large number of electronic states at the highest occupied molecular orbital energy level, MPA-and MHA-protected gold nanoclusters exhibit high stability and photostability. In addition, gold nanoclusters with different ligands exhibited different selective enzyme-mimicking activities of peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT). Imaging in vivo showed that gold nanoclusters could accomplish reliable imaging of cerebral vasculature, hindlimb vessels, and spine as well as monitor renal clearance. The stable nanoclusters allow the time window of imaging to reach 125 min for hindlimb imaging and 270 min for spinal imaging. The gold nanoclusters exhibit a high signal-tonoise ratio of up to 11 for whole-body imaging and show efficient renal clearance and low toxicity at an injected dose of 50 mg/kg.

show abstract

Surface functionalization: an efficient alternative for promoting the catalytic activity of closed shell gold clusters

Abstract: Surface functionalization through adsorption of ligands or non-metal atoms is considered to be an interesting and viable approach for tuning the physicochemical properties of gold clusters. Highly stable and magic...

Cited by 2 publications

References 66 publications

Probing the Site-Specific Reactivity and Catalytic Activity of Ag_n (n = 15–20) Silver Clusters

Probing the Site-Specific Reactivity and Catalytic Activity of Ag_n (n = 15–20) Silver Clusters

Ligand Engineering of Gold Nanoclusters for NIR-II Imaging

Contact Info

Product

Resources

About

Surface functionalization: an efficient alternative for promoting the catalytic activity of closed shell gold clusters

Abstract: Surface functionalization through adsorption of ligands or non-metal atoms is considered to be an interesting and viable approach for tuning the physicochemical properties of gold clusters. Highly stable and magic...

Cited by 2 publications

References 66 publications

Probing the Site-Specific Reactivity and Catalytic Activity of Agn (n = 15–20) Silver Clusters

Probing the Site-Specific Reactivity and Catalytic Activity of Agn (n = 15–20) Silver Clusters

Ligand Engineering of Gold Nanoclusters for NIR-II Imaging

Contact Info

Product

Resources

About

Probing the Site-Specific Reactivity and Catalytic Activity of Ag_n (n = 15–20) Silver Clusters

Probing the Site-Specific Reactivity and Catalytic Activity of Ag_n (n = 15–20) Silver Clusters