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The direct C−H to C−N bond conversion at room temperature using heterogeneous visible‐light catalysts is both interesting and challenging. Herein, we disclosed visible‐light‐promoted hydroacylation of azodicarboxylates using uranyl‐organic framework [UO2(OH)(cpt)]n (Ucpt, Hcpt=4‐(4′‐carboxyphenyl)‐1,2,4‐triazole) as an efficient heterogeneous hydrogen atom transfer photocatalyst. In this procedure, diverse benzaldehydes are compatible using dimethyl carbonate (DMC) as a green solvent at room temperature, achieving direct conversion of C−H to C−N bond with excellent yields (up to 99%). The key to excellent catalytic activity lies in the fact that the coordination of the conjugated ligand changes the HOMO energy level of Ucpt, resulting in more active sites and longer‐lived photo excitons. Simultaneously, this heterogeneous photocatalyst can be easily separated and reused for seven successive cycles and maintain high catalytic activity, showing outstanding sustainability and recyclability. [ABSTRACT FROM AUTHOR]

A 4p–4f cluster incorporated polyoxometalate (POM), namely, H18{[(H4pic)4Eu10Se13O28(H2O)12](α-GeW9O34)4·40H2O (1-Eu, H4pic = isonicotinic acid), has been first synthesized and characterized. 1-Eu features an interesting four-shell structure, representing the largest Se-4f cluster incorporated POM known to date. Besides, 1-Eu exhibits excellent Lewis acid–base catalytic activity and reusablity in catalyzing the gram-scale dehydration condensation reaction of hydrazines and 1,3-diketones to synthesize polysubstituted pyrazoles. [ABSTRACT FROM AUTHOR]

Two new three-dimensional (3D) metal–organic frameworks (MOFs), namely {[Cu2(L)(4,4′-bipy)(OH)]·H2O}n (1) and {[Mn3(L)2(4,4′-bipy)(DMA)2]·H2O}n (2), were constructed by a newly synthesized thioether carboxylic acid ligand 5-((formic acid-3-sulfur)methyl)isophthalic acid (H3L) and 4,4′-bipyridine (4,4′-bipy). Thioether bonds in H3L can rotate freely in space, which are conducive in constructing MOFs with rich and stable structures. Simultaneously, the uncoordinated sulfur atoms affect the polarity of the framework and play an important role in adsorption. Gas adsorption results indicated that 1 can selectively adsorb CO2 from the mixture of CH4/CO2. Moreover, due to the high catalytic activity of [Cu4(COO)6N4O2] clusters, 1 is also an excellent recyclable catalyst that can chemically fix CO2 into cyclic carbonate under mild solvent-free conditions. Therefore, 1 may be explored as a dual-functional material for industrial adsorption and catalysis. [ABSTRACT FROM AUTHOR]

The coordination preference of different metal ions and ligands have an immense influence on the constructions of functional MOF materials. In this work, two new monometallic complexes, namely [Ag(HL)(bipy)0.5] (1) and {[Tb(L)1.5(H2O)]⋅4 H2O}n (2) (bipy=4,4‐bipyridine), have been synthesized successfully by employing a bifunctional 2‐(imidazol‐1‐yl)terephthalic acid (H2L) ligand. After that, two new different heterometallic–organic frameworks (HMOFs), namely {[TbAg(L)2(H2O)3]⋅H2O}n (3) and [TbAg(L)2(H2O)]n (4), were obtained from complexes 1 and 2 as the precursors based on a rational stepwise construction strategy and the theory of hard and soft acids and bases (HSAB principle), respectively. The HMOFs bearing dual metallic catalytic sites (Tb and Ag) can be used as heterogeneous catalysts without losing performance for the chemical fixation of CO2 with epoxides including the sterically hindered epoxides, demonstrating some of the highest reported catalytic activity values. This work may provide a new synthetic route toward tailoring new HMOFs with excellent catalytic activity. [ABSTRACT FROM AUTHOR]

A convenient and direct approach has been developed for the preparation of pyrazole derivatives by the condensation cyclization of hydrazines/hydrazide and 1,3‐diketones in the presence of Cu1.5PMo12O40 (0.33 mol%) under mild conditions (r.t.‐60 °C, 10–30 min). Notably, the reaction was found to be scalable as 99% yield was obtained when the reaction was performed at a 5‐mmol scale. This solvent‐free and halogen‐free catalytic system represents an effective economic and environmentally friendly method for the construction of pyrazoles. Cu1.5PMo12O40 was found to be an effective, inexpensive and green catalyst for the preparation of pyrazole derivatives by the condensation–cyclization of hydrazines and 1,3‐diketones under mild conditions (room temperature to 60°C, 10–30 min). [ABSTRACT FROM AUTHOR]