结构化学最新文献

The ligand effects have been extensively investigated in Au and Ag nanoclusters, while corresponding research efforts focusing on Cu nanoclusters remain relatively insufficient. Such a scarcity could primarily be attributed to the inherent instability of Cu nanoclusters relative to their Au/Ag analogues. In this work, we report the controllable preparation and structural determination of a hydride-containing Cu₂₈ nanocluster with a chemical formula of Cu₂₈H₁₀(SPh^pOMe)₁₈(DPPOE)₃. The combination of Cu₂₈H₁₀(SPh^pOMe)₁₈(DPPOE)₃ and previously reported Cu₂₈H₁₀(SPh^oMe)₁₈(TPP)₃ constructs a structure-correlated cluster pair with comparable structures and properties. Accordingly, the ligand effects in directing the geometric structures and physicochemical properties (including optical absorptions and catalytic activities towards the selected hydrogenation) of copper nanoclusters were analyzed. Overall, this work presents a structure-correlated Cu₂₈ pair that enables the atomic-level understanding of ligand effects on the structures and properties of metal nanoclusters.

Photoluminescence (PL) has been increasingly applied in anticounterfeiting and encryption as counterfeiting becomes more prevalent. However, common luminescent encryption techniques are based on static PL measurements and are easy to counterfeit. In this work, we have developed a thermal vapor deposition (TVD) approach using melem as the unique starting material to synthesize highly homogeneous carbon nitride (CN) thin films featuring unique dynamic PL switching properties. After being irradiated by a white LED, the blue PL intensity of the CN film increases significantly and then fades in darkness, demonstrating excellent recyclability. Experimental results prove that CN films contain cyano groups in the structure, and density functional theory (DFT) calculations indicate that the integration of cyano groups results in traps within the bandgap of CN, suggesting that the dynamic PL switching effect is essentially associated with the fullness of the trap states. We have therefore developed an advanced luminescent device for the secure transmission of encrypted information through controlled illumination. It can be easily read with a portable UV (365 nm) lamp and effectively erased using the white LED, thereby preventing information leakage and showing great potential for many applications.

Photocatalytic CO₂ hydrogenation reactions can produce high-value-added chemicals for industry, solving the environmental problems caused by excessive CO₂ emissions. Iron oxides are commonly used in photocatalytic reactions due to their various structures and suitable band gaps. Nevertheless, the structural evolution and real active components during photocatalytic CO₂ hydrogenation reaction are rarely studied. Herein, a variety of iron oxides including α-Fe₂O₃, γ-Fe₂O₃, Fe₃O₄ and FeO were derived from Prussian blue precursors to investigate the CO₂ hydrogenation performance, structural evolution and active components. Especially, the typical α- and γ-Fe₂O₃ are converted to Fe₃O₄ during the reaction, while Fe/Fe_xO_y remains structurally stable. Meanwhile, it is confirmed that Fe₃O₄ is the main active component for CO production and the formation of hydrocarbons (CH₄ and C₂–C₄) are highly dependent on the Fe/Fe_xO_y heterojunctions. The optimal yields of CO, CH₄ and C₂–C₄ hydrocarbons over the best catalyst (FeFe-550) can achieve 4 mmol g⁻¹ h⁻¹, 350 μmol g⁻¹ h⁻¹ and 150 μmol g⁻¹ h⁻¹, respectively due to their suitable metal/oxide component distribution. This work examines the structural evolution of different iron oxide catalysts in the photocatalytic CO₂ hydrogenation reaction, identifies the active components as well as reveals the relationship between components and the products, and offers valuable insights into the efficient utilization of CO₂.