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1. H ₂ evolution from H ₂ O via O–H oxidative addition across a 9,10-diboraanthracene

   https://doi.org/10.1039/D0CC05261B  

   Taylor, Jordan W.; Harman, W. Hill (November 2020, Chemical Communications)

   null (Ed.)

   The water reactivity of the boroauride complex ([Au(B 2 P 2 )][K(18-c-6)]; (B 2 P 2 , 9,10-bis(2-(diisopropylphosphino)-phenyl)-9,10-dihydroboranthrene) and its corresponding two-electron oxidized complex, Au(B 2 P 2 )Cl, are presented. Au(B 2 P 2 )Cl is tolerant to H 2 O and forms the hydroxide complex Au(B 2 P 2 )OH in the presence of H 2 O and triethylamine. [Au(B 2 P 2 )]Cl and [Au(B 2 P 2 )]OH are poor Lewis acids as judged by the Gutmann–Becket method, with [Au(B 2 P 2 )]OH displaying facile hydroxide exchange between B atoms of the DBA ring as evidenced by variable temperature NMR spectroscopy. The reduced boroauride complex [Au(B 2 P 2 )] − reacts with 1 equivalent of H 2 O to produce a hydride/hydroxide product, [Au(B 2 P 2 )(H)(OH)] − , that rapidly evolves H 2 upon further H 2 O reaction to yield the dihydroxide compound, [Au(B 2 P 2 )(OH) 2 ] − . [Au(B 2 P 2 )]Cl can be regenerated from [Au(B 2 P 2 )(OH) 2 ] − via HCl·Et 2 O, providing a synthetic cycle for H 2 evolution from H 2 O enabled by O–H oxidative addition at a diboraanthracene unit. 

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2. [Au(Np ^# )Cl]: highly reactive and broadly applicable Au( i )–NHC catalysts for alkyne π-activation reactions

   https://doi.org/10.1039/D3CY00717K  

   Rahman, Md Mahbubur; Gao, Pengcheng; Zhao, Qun; Lalancette, Roger; Szostak, Roman; Szostak, Michal (August 2023, Catalysis Science & Technology)

   We report [Au(NHC)Cl] complexes featuring IPr# ligands that hinge upon modular peralkylation of aniline. Wingtip-flexible [Au(Np#)Cl] is a broadly applicable catalyst with the reactivity outperforming [Au(IPr)Cl] and [Au(IPr*)Cl] complexes. 

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3. ZnO-Au Hybrid Metamaterial Thin Films with Tunable Optical Properties

   https://doi.org/10.3390/cryst14010065  

   Bhatt, Nirali A; Paldi, Robynne L; Barnard, James P; Lu, Juanjuan; He, Zihao; Yang, Bo; Shen, Chao; Song, Jiawei; Sarma, Raktim; Siddiqui, Aleem; et al (January 2024, Crystals)

   ZnO-Au nanocomposite thin films have been previously reported as hybrid metamaterials with unique optical properties such as plasmonic resonance properties and hyperbolic behaviors. In this study, Au composition in the ZnO-Au nanocomposites has been effectively tuned by target composition variation and thus resulted in microstructure and optical property tuning. Specifically, all the ZnO-Au nanocomposite thin films grown through the pulsed laser deposition (PLD) method show obvious vertically aligned nanocomposite (VAN) structure with the Au nanopillars embedded in the ZnO matrix. Moreover, the average diameter of Au nanopillars increases as Au concentration increases, which also leads to the redshifts in the surface plasmon resonance (SPR) wavelength and changes in the hyperbolic behaviors of the films. As a whole, this work discusses how strain-driven tuning of optical properties and microstructure resulted through a novel Au concentration variation approach which has not been previously attempted in the ZnO-Au thin film system. These highly ordered films present great promise in the areas of sensing, waveguides, and nanophotonics to name a few. 

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4. Optical properties of nanoporous gold foams

   https://doi.org/10.1063/1.5030128  

   Asane, J_K; Qi, Z.; Biener, M_M; Liberman, V.; Noginov, M_A (September 2018, AIP Advances)

   We fabricated and experimentally studied Au nano-foams and Al2O3 scaffolds filled with Au nanoparticles (NPs). We found that while the reflectance spectra of Au nano-foams depended very little on the 8-10 nm Al2O3 ALD coating, the spectra were highly sensitive to annealing, which increased the sizes of voids and ligaments from 50-100 nm to ∼300 nm. The effective dielectric permittivities of the Au nano-foams and Al2O3 scaffolds with Au NPs were extremely high, ∼50. At the same time, Au nano-foams covered with a dielectric (MgF2) featured bright structural colors, calling for the model, which extends beyond the effective medium approximation. 

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5. Gold Catalysts Synthesized Using a Modified Incipient Wetness Impregnation Method for Propylene Epoxidation

   https://doi.org/10.1002/cctc.202001053  

   Lu, Zheng; Kunisch, Jacob; Gan, Zhuoran; Bunian, Muntaseer; Wu, Tianpin; Lei, Yu (September 2020, ChemCatChem)

   Abstract Propylene epoxidation in the presence of oxygen and hydrogen were measured for a series of Au/TS‐1 catalysts prepared by a modified incipient wetness impregnation (mIWI) method. This method enables precise control of the Au : Ti ratio in the Au/TS‐1 catalysts. The optimized Au/TS‐1 catalyst exhibited 12 % propylene conversion, 87 % PO selectivity, and 25 % hydrogen efficiency. The particle size of gold nanoparticles prepared by the modified IWI was between 2 and 3 nm, as demonstrated by XRD patterns, STEM images, and X‐ray absorption spectroscopy at the Au L₃edge. XPS spectra showed that the surface species on the catalysts were similar. UV‐Vis spectra suggested that in the modified IWI method, the chlorine ligands in Au(Cl)₄⁻were replaced by hydroxyl groups, which contributes to form small gold nanoparticles. Kinetic studies showed that the active sites of Au(mIWI)/TS‐1 are similar to the Au(DP)/TS‐1 prepared by deposition precipitation. 

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