The crystal structure of the [Ag62S12(SBu(t))32](2+) nanocluster (denoted as NC-I) has been successfully determined, and it shows a complete face-centered-cubic (FCC) Ag14 core structure with a Ag48(SBu(t))32 shell configuration interconnected by 12 sulfide ions, which is similar to the [Ag62S13(SBu(t))32](4+) structure (denoted as NC-II for short) reported by Wang. Interestingly, NC-I exhibits prominent differences in the optical properties in comparison with the case of the NC-II nanocluster. We employed femtosecond transient absorption spectroscopy to further identify the differences between the two nanoclusters. The results show that the quenching of photoluminescence in NC-I in comparison to that of NC-II is caused by the free valence electrons, which dramatically change the ligand to metal charge transfer (LMCT, S 3p → Ag 5s). To get further insight into these, we carried out time-dependent density functional theory (TDDFT) calculations on the electronic structure and optical absorption spectra of NC-I and NC-II. These findings offer a new insight into the structure and property evolution of silver cluster materials.

Searching for highly efficient and stable bifunctional electrocatalysts toward hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is highly desirable for the practical application of water electrolysis under alkaline electrolyte. Although electrocatalysts based on transition metal sulfides (TMSs) are widely studied as efficient (pre)catalysts toward OER under alkaline media, their HER performances are far less than the state‐of‐the‐art Pt catalyst. Herein, the synthesis of nitrogen doped 3D dandelion‐flower‐like CoS2 architecture directly grown on Ni foam (N‐CoS2/NF) is reported that possesses outstanding HER activity and durability, with an overpotential of 28 mV to obtain the current density of 10 mA cm−2, exceeding almost all the documented TMS‐based electrocatalysts. Density functional theory calculations and experimental results reveal that the d‐band center of CoS2 could be efficiently tailored by N doping, resulting in optimized adsorption free energies of hydrogen (ΔG*H) and water , which can accelerate the HER process in alkaline electrolyte. Besides, the resulting N‐CoS2/NF also displays excellent performance for OER, making it a high‐performance bifunctional electrocatalyst toward overall water splitting, with a cell voltage of 1.50 V to achieve 10 mA cm−2.

Molecules capable of performing highly efficient energy transfer and ultrafast photoinduced electron transfer in well-defined multichromophoric structures are indispensable to the development of artificial photofunctional systems. Herein, we report on the synthesis, characterization, and photophysical properties of a rationally designed multichromophoric tetracationic cyclophane, DAPPBox, containing a diazaperopyrenium (DAPP) unit and an extended viologen (ExBIPY) unit, which are linked together by two p-xylylene bridges. Both H NMR spectroscopy and single-crystal X-ray diffraction analysis confirm the formation of an asymmetric, rigid, box-like cyclophane, DAPPBox. The solid-state superstructure of this cyclophane reveals a herringbone-type packing motif, leading to two types of π···π interactions: (i) between the ExBIPY unit and the DAPP unit (π···π distance of 3.7 Å) in the adjacent parallel cyclophane, as well as (ii) between the ExBIPY unit (π···π distance of 3.2 Å) and phenylene ring in the closest orthogonal cyclophane. Moreover, the solution-phase photophysical properties of this cyclophane have been investigated by both steady-state and time-resolved absorption and emission spectroscopies. Upon photoexcitation of DAPPBox at 330 nm, rapid and quantitative intramolecular energy transfer occurs from the ExBIPY unit to the DAPP unit in 0.5 ps to yield DAPP. The same excitation wavelength simultaneously populates a higher excited state of DAPP which then undergoes ultrafast intramolecular electron transfer from DAPP to ExBIPY to yield the DAPP-ExBIPY radical ion pair in τ = 1.5 ps. Selective excitation of DAPP at 505 nm populates a lower excited state where electron transfer is kinetically unfavorable.

Atomically precise nanoclusters (APNCs), as ideal model catalysts, revealed great advantages to deep-understand of reaction mechanisms in heterogeneous catalysis. Boosting the activity of APNCs is the most critical issue under the premise of maintaining structure invariance. Herein, utilizing Metal-Support Interaction (MSI) strategy, we prepared an excellent and recyclable catalyst for aerobic oxidation by combination of an otherwise inert nanocluster [Pd 3 Cl(PPh 2 ) 2 (PPh 3 ) 3 ] + [SbF 6 ] À (denoted as Pd 3 Cl) with functional titanate nanotubes (TNT). The promising Pd 3 Cl/TNT composite gives rise to excellent conversion with 100% selectivity without any additives at 30 8C under an oxygen pressure. This result is unprecedented in ligand-on nanocluster catalysts without high temperature calcination. The distinct difference between their activities of Pd 3 Cl/TNT composite and fresh Pd 3 Cl nanocluster is explained by the presence of the MSI effect, as confirmed using X-ray photoelectron spectroscopy (XPS) analysis. Theoretical simulations are further carried out to elucidate the catalytic mechanism, indicating the MSI effect promotes the crucial b-H elimination step in both kinetic and thermodynamic aspects. This work presents the example of atomic-level understanding of the effect of MSI on facilitating the APNCs catalytic properties.

We have conducted a theoretical study on the electronic transport behaviour of two molecular diodes connected in series. The single diode is composed of o-nitrotoluene and o-aminotoluene connecting via a σ-bridge, and the tandem diode is two single diodes connecting via a π-bridge. It was found that the rectification ratio was greatly improved due to the electronic coupling in the tandem diode. The rectification ratio of the tandem molecular diode can be 20 times higher than that of the single diode, which is quite different from a traditional diode. In addition, we also found that the high rectification ratio correlates with the intramolecular coupling of the tandem system. When long conjugated wires are employed in two single diodes, the rectification ratio is reduced.