Yan-Shang Kang

Rh(III)-Catalyzed meta-C–H Olefination Directed by a Nitrile Template

A range of Rh(III)-catalyzed ortho-C-H functionalizations have been developed; however, extension of this reactivity to remote C-H functionalizations through large-ring rhodacyclic intermediates has yet to be demonstrated. Herein we report the first example of the use of a U-shaped nitrile template to direct Rh(III)-catalyzed remote meta-C-H activation via a postulated 12-membered macrocyclic intermediate. Because the ligands used for Rh(III) catalysts are significantly different from those of Pd(II) catalysts, this offers new opportunities for future development of ligand-promoted meta-C-H activation reactions.

A facile approach to fabricate porous UMCM-150 nanostructures and their adsorption behavior for methylene blue from aqueous solution

Well-dispersed hierarchical flower-like and net-like architectures of UMCM-150 were successfully prepared by a facile and rapid method at room temperature. Owing to the high surface area and pore volume, the UMCM-150 flower-like nanostructures exhibit excellent adsorption capability for the dye of methylene blue (MB) with a maximum capacity of 560 mg g−1, which is higher than that of most materials reported to date. The influence of variables such as initial pH and MB concentration, contact time and shape of UMCM-150 nanostructures was investigated. The results indicate that the UMCM-150 nanostructures have promising application in the MB dye containing wastewater treatment.

Ligand‐Promoted Rhodium(III)‐Catalyzed ortho‐C−H Amination with Free Amines

Ligand development for rhodium(III)-catalyzed C-H activation reactions has largely been limited to cyclopentadienyl (Cp) based scaffolds. 2-Methylquinoline has now been identified as a feasible ligand that can coordinate to the metal center of Cp*RhCl to accelerate the cleavage of the C-H bond of N-pentafluorophenylbenzamides, providing a new structural lead for ligand design. The compatibility of this reaction with secondary free amines and anilines also overcomes the limitations of palladium(II)-catalyzed C-H amination reactions.

Functional group effects on structure and topology of cadmium(II) frameworks with mixed organic ligands

Four new Cd(II) frameworks [Cd(tib)(p-BDC-OH)]·H2O (1), [Cd(tib)(m-BDC-OH)]·3H2O (2), [Cd(tib)(m-BDC-CH3)]·3H2O (3) and [Cd(tib)(m-BDC-CH3)]·11H2O (4) (tib = 1,3,5-tris(1-imidazolyl)benzene, p-H2BDC-R = 2-R-1,4-benzenedicarboxylic acid, m-H2BDC-R = 5-R-1,3-benzenedicarboxylic acid, R = OH or CH3) have been successfully synthesized under solvothermal conditions. 1 is a 3D framework with a Point symbol of {810}{83} constructed from Cd-tib 3D net and Cd-p-BDC-OH 1D helical chain. 2 and 3 possess different 3D structures with the same topology of {4·62}{4·66·83} built from Cd-tib 2D networks and Cd-m-BDC-R 1D linear chains, while 4 is a 2D network with {42·67·8}{42·6} topology based on Cd-tib and Cd-m-BDC-CH3 1D chains. The results show that the dicarboxylate ligands and reaction medium play important role in determining the structures of MOFs. Moreover, ferroelectric and photoluminescence properties of the complexes were studied.

Efficient and Reusable Metal−Organic Framework Catalyst for Carboxylative Cyclization of Propargylamines with Carbon Dioxide

Carbon dioxide (CO2) capture and transformation are important for decreasing the concentration of atmospheric CO2. To effectively capture CO2 and further fix it into valuable chemical products, functionalized dynamic metal–organic frameworks (MOFs) have been utilized not only because of their inherent cavity for accommodating CO2 but also owing to their reversible structural transformations in response to external stimuli for regulating the reaction. Herein, we report a dynamic and functional MOF [Cd3(L)2(BDC)3]2⋅16 DMF (MOF‐1 a; DMF=N,N‐dimethylformamide) achieved by reaction of the amino tripodal imidazole ligand N1‐(4‐(1 H‐imidazol‐1‐yl)benzyl)‐N1‐ (2‐aminoethyl)ethane‐1,2‐diamine (L) and 1,4‐benzenedicarboxylic acid (H2BDC) with cadmium salt. MOF‐1 a not only shows unprecedented high catalytic activity [initial turnover number (TON) up to 9300] and broad substrate scope for the carboxylative cyclization of propargylamines with CO2, but also can be switched on and off upon reversible structural transformation owing to its dynamic five‐fold interpenetrating structure. Further studies demonstrate that MOF‐1 a shows selective catalytic properties depending on the size of substrates, similarly to sophisticated biological systems.

Sorption and sensing properties of coordination polymers with mixed 1,3,5-tri(1-imidazolyl)benzene and 2,6-naphthalenedicarboxylate ligands

Under hydro/solvothermal conditions, the assembly of imidazole-containing ligand 1,3,5-tri(1-imidazolyl)benzene (tib) and 2,6-naphthalenedicarboxylic acid (H2NDC) with different transition metal salts provides five new coordination polymers [M2(tib)2(NDC)(H2O)2] SO4·XH2O (1: M = Cd, X = 4; 2: M = Co, X = 4; 3: M = Ni, X = 3), [Cd2(tib)2(NDC)(NO3)2] 2.5DMF·H2O (4) (DMF = N,N-dimethylformamide) and [Zn(tib)2/3(NDC)] (5). 1–3 have the same three-fold interpenetrating 3D framework structures with SO42− as counteranion, while 4 with NO3− as terminal ligand exhibits a wave-like 2D layer structure, which is further extended into a 3D framework by hydrogen bonds. In addition, complex 5 obtained at high temperature is an interesting two-fold interpenetrating 3D structure. Sorption and photoluminescence properties of the complexes were investigated. 4 displays selective adsorption of CO2 over N2. Furthermore, 1 and 4 can be used to probe acetone molecules selectively and rapidly via fluorescence quenching.

Rhodium-Catalyzed Direct Ortho C–H Arylation Using Ketone as Directing Group with Boron Reagent

A general method for selective ortho C-H arylation of ketone, with boron reagent enabled by rhodium complexes with excellent yields, is developed. The transformation is characterized by the use of air-stable Rh catalyst, high monoarylation selectivity, and excellent yields of most of the substrates.