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An efficient and highly selective phosphine-free NN-manganese(I) complex catalyst system was developed for the acceptorless dehydrogenative coupling of alcohols with amines to form imines. The coupling reactions underwent at 3 mol % catalyst loading, and a large range of alcohols and amines with diverse functional groups was applied, including challenging diol and diamine. The target imine products were obtained in good to excellent yields. The present work provides an alternative method to construct highly active nonprecious metal complex catalysts based on phosphine-free ligands.

Electrochemical sensors, with their outstanding sensitivity, excellent selectivity, ease of operation, and lower manufacturing costs, have found widespread applications in fields such as disease diagnosis, environmental monitoring, and food safety. In the development of sensing materials, metal-organic frameworks (MOFs) have become a research hotspot due to their high specific surface area, tunable pore structures, and high designability. Recently, conductive metal-organic frameworks (CMOFs) have brought innovative opportunities to the field of electrochemical sensing, attributing to their remarkable capabilities in catalysis, electron transport, and signal amplification. This review summarizes the significant progress of CMOFs in the field of electrochemical sensing. Firstly, the design and synthesis strategies for CMOFs used in electrochemical sensing are explored, including enhancing the electrochemical properties of MOFs through precise design of different metal nodes and ligands or viapost-synthetic modification techniques, covering Cu-based CMOFs, Ni-based CMOFs, Fe-based CMOFs, and CMOF composites. Furthermore, this article elaborately discusses the breakthrough achievements of electrochemical sensors based on CMOFs in applications such as the determination of inorganic ions, detection of organic pollutants, and recognition of gases and biomolecules, and introduces the principles of electrochemical sensing methods and the role of CMOFs in enhancing the performance of electrochemical sensors. Finally, this review analyzes the main challenges currently faced by CMOFs in the field of electrochemical sensors and offers perspectives on their future development. These challenges mainly include stability, selectivity, production costs, and the realization of their large-scale application. CMOFs provide new ideas and material platforms for the development of electrochemical sensors. As researchers deepen their understanding of their properties and technological advances continue, the application prospects of CMOF-based electrochemical sensors will be even broader.

Pincer-type ruthenium(II)-NNN complex catalysts bearing a chiral bis(NHTs)-substituted imidazolyl-oxazolinyl-pyridine ligand were synthesized and structurally characterized by NMR, IR, elemental analysis, and X-ray single-crystal crystallographic determinations. The two NHTs groups substituted on the imidazolyl moiety of the chiral NNN ligand exhibited a remarkable effect on the enantioselectivity of the Ru(II)-NNN complexes for the asymmetric transfer hydrogenation (ATH) of ketones. The Ru(II)-NNN complex bearing a chiral (NHTs)2-substituted imidazolyl-(isopropyl)oxazolinyl-pyridine ligand exhibited excellent catalytic activity, reaching an enantioselectivity up to 99.9% ee for the target alcohol products.

Bimetallic ruthenium(II) complexes bearing a bis(pyrazolylimidazolylpyridine) ligand bridged by a rotatable single C–C bond or methylene linker were synthesized, structurally characterized, and exhibited diverse catalytic activities for the transfer hydrogenation (TH) reactions of ketones in refluxing isopropyl alcohol. Both the unprotected NH functionality and bridging methylene moiety demonstrated an acceleration effect on such TH reactions. Combination of the NH and CH2skeleton functionalities into the bimetallic Ru(II)–NNN complexes remarkably enhanced the catalytic activities of the complex catalysts. Density functional theory calculations have suggested that the difference in the catalytic activities of these Ru(II)–NNN complexes is attributed to the inherent nucleophilic character of the coordinative nitrogen atoms in the bis(NNN) ligand, and the metal–metal interaction resulted from the number of net natural bond orbital charges on these nitrogen atoms.

A pincer-type Ru(II)-NNP complex bearing a pyrazolyl-(NH-PtBu2)-pyridine ligand was synthesized and structurally characterized by NMR, IR, elemental analysis, and X-ray single-crystal crystallographic determinations, which efficiently catalyzed the synthesis of multisubstituted pyrroles and pyridines by means of the reactions of secondary alcohols and β- or γ-amino alcohols through deoxygenation and selective C–N and C–C bond formation. The coupling reactions took place with 0.3 mol % catalyst loading and tolerated diverse functional groups. The present work provides an alternative method to construct highly active transition-metal complex catalysts from readily available ligands.