We report herein a series of Cp*Ir complexes containing a rigid 8-aminoquinoline­sulfonamide moiety as highly efficient catalysts for the dehydrogenation of formic acid (FA). The complex [Cp*Ir­(L)­Cl] (HL = N-(quinolin-8-yl)­benzene­sulfonamide) displayed a high turnover frequency (TOF) of 2.97 × 104 h–1 and a good stability (>100 h) at 60 °C. Comparative studies of [Cp*Ir­(L)­Cl] with the rigid ligand and [Cp*Ir­(L′)­Cl] (HL′ = N-propylpypridine-2-sulfonamide) without the rigid aminoquinoline moiety demonstrated that the 8-amino­quinoline moiety could dramatically enhance the stability of the catalyst. The electron-donating ability of the N,N′-chelating ligand was tuned by functionalizing the phenyl group of the L ligand with OMe, Cl, and CF3 to have a systematical perturbation of the electronic structure of [Cp*Ir­(L)­Cl]. Experimental kinetic studies and density functional theory (DFT) calculations on this series of Cp*Ir complexes revealed that (i) the electron-donating groups enhance the hydrogen formation step while slowing down the β-hydride elimination and (ii) the electron-withdrawing groups display the opposite effect on these reaction steps, which in turn leads to lower optimum pH for catalytic activity compared to the electron-donating groups.

Developing novel carbonaceous materials with definite chemical structures is conducive to understanding structure-property relationships and expanding their applications in supported metal catalysts. Herein, a brand-new pyridine-substituted graphdiyne (Py-GDY) is synthesized...

Surface functionalization of carbon materials is of interest in many research fields, such as electrocatalysis, interfacial engineering, and supercapacitors. As an emerging carbon material, γ-graphyne has attracted broad attention. Herein, we report that the surface functionalization of a γ-graphyne-like carbon material (γ-G1) is achieved by immobilizing functional groups via the click chemistry. Texture analysis of aberration-corrected microscopy, X-ray photoelectron spectroscopy, and electrochemistry confirm the successful surface modification of γ-G1 through a strong covalent linkage 1,2,3-triazole. The direct linkage of functional groups on γ-G1 via the click chemistry represents a general method for preparing other functional materials by using γ-graphyne-like materials as a skeleton.