Understanding the catalytic mechanism of bimetallic nanocatalysts remains challenging. Here, we adopt an adsorbate mediated thermal reduction approach to yield monodispersed AuPd catalysts with continuous change of the Pd-Au coordination numbers embedded in a mesoporous carbonaceous matrix. The structure of nanoalloys is well-defined, allowing for a direct determination of the structure-property relationship. The results show that the Pd single atom and dimer are the active sites for the base-free oxidation of primary alcohols. Remarkably, the d -orbital charge on the surface of Pd serves as a descriptor to the adsorbate states and hence the catalytic performance. The maximum d -charge gain occurred in a composition with 33–50 at% Pd corresponds to up to 9 times enhancement in the reaction rate compared to the neat Pd. The findings not only open an avenue towards the rational design of catalysts but also enable the identification of key steps involved in the catalytic reactions.

It is very challenging to realize well-controlled structural transformations in artificial supramolecules. Herein we report the construction of a novel family of multi-bisthienylethene hexagons with precise control of the shape and size as well as the specific number of photochromic units via coordination-driven self-assembly. These newly developed multi-bisthienylethene hexagons are highly sensitive and responsive to photostimuli, especially allowing for quantitative reversible supramolecular transformations triggered by light irradiation.

The completely C2-selective arylation of N-methylindole was achieved by using a reusable solid Pd catalyst and water as a solvent without any other ligands or additives or exclusion of air. The catalysts possess well-dispersed Pd nanoparticles (~ 1.5 nm), N-containing functional groups (~ 11 wt%), and uniform mesopores (~ 5 nm). The turnover frequency (TOF) is calculated to be 82 h -1 .Arylations of both N-H indoles and N-protected indoles with diaryliodonium salts were achieved to give the desired products in high to excellent isolated yields in water.Mercapto-functionalized silica as a selective trapping agent, together with hot infiltration, confirms the undetected leaching of Pd. The catalyst samples can be reused at least 8 times without any additional activation treatment. The catalytic performance of the Pd catalyst is also compared with the performance of other mesoporous Pd catalysts on silica, carbon, and resins. The catalytic activity and stability of the present catalyst may be related to the well-dispersed Pd nanoparticles, the electron-rich environment stabilized by the N-containing functional groups, and the large, uniform mesopores.

A coordination-assisted pyrolysis procedure was adopted to encapsulate palladium (Pd) nanoparticles in a mesoporous carbonaceous matrix. X-ray diffraction and transmission electron microscopy measurements revealed that approximately 2.5 nm nanoparticles were highly dispersed inside the well-ordered porous framework. High-resolution TEM and temperature-programmed hydride decomposition analysis demonstrated the formation of interstitial carbon in the Pd lattice. Diffuse reflectance infrared Fourier transform spectroscopy indicated that carbon species could be deposited on low-coordinated surface sites of the Pd particles. This catalyst exhibited high activity in the selective hydrogenation of cinnamaldehyde (CAL) at 80 °C under an H2 pressure of 1.0 MPa (turnover frequency (TOF) of 2.4 s–1) to produce hydrocinnamyl aldehyde with high selectivity (HCAL; approximately 80%) in water and could be reused eight times with no clear activity loss. A trapping agent poisoning experiment using solid SH-SBA-15 revealed unobvious leaching of Pd into the solution. Exposure to thiourea with a S:Pd ratio of 0.1 resulted in slight activity and undetectable selectivity losses over the current catalyst in the selective hydrogenation of CAL at 80 °C under an H2 pressure of 1.0 MPa. However, a 50% activity loss was observed for commercial Pd/C. Even after an increase in the thiourea concentration to a S:Pd ratio of 3, the TOF remained at 1.9 s–1 with a negligible effect on the HCAL selectivity. Nearly complete deactivation of Pd/C occurred upon high exposure to thiourea. DFT calculations showed that the presence of surface or subsurface carbon can enhance the poison tolerance of the encapsulated Pd catalysts. The enhanced hydrogenation activity and strong poison tolerance are consistent with the interpretation that Pd nanoparticles are modified by carbonaceous deposits.

A photochemically active dithiazolethene BN was designed and synthesized, exhibiting a specific gated photochromism. That is, the photochromic reactivity of BN is prevented to a great extent by BF(3), showing a "Lock" gate.