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Abstract The simultaneous construction of multiple stereogenic elements in a single step is highly appealing and desirable in the field of asymmetric synthesis. Furthermore, the catalytic enantioselective synthesis of inherently chiral calix[n]arenes with high enantiopurity has long been a challenging endeavor. Herein, we report an enantioselective cobalt-catalyzed C–H activation/annulation for the efficient construction of inherently chiral calix[4]arenes bearing multiple C–N axially chiral element. By employing the benzamide tethered calix[4]arene as the substrate, the C–H annulation with alkynes can be successfully accomplished, leading to the generation of multiple stereogenic elements. A wide range of calix[4]arenes and alkynes are found to be well compatible, and exhibit good yields, high enantioselectivity and excellent diastereoselectivity. Notably, the gram-scale reaction, catalytic application, synthetic transformations, and chiral recognition further showcase the potential applications of this protocol.

Abstract The N−N atropisomer, as an important and intriguing chiral system, was widely present in natural products, pharmaceutical lead compounds, and advanced material skeletons. The anisotropic structural characteristics caused by its special axial rotation have always been one of the challenges that chemists strive to overcome. Herein, we report an efficient method for the enantioselective synthesis of N−N axially chiral frameworks via a cobalt-catalyzed atroposelective C-H activation/annulation process. The reaction proceeds under mild conditions by using Co(OAc)2·4H2O as the catalyst with a chiral salicyl-oxazoline (Salox) ligand and O2 as an oxidant, affording a variety of N−N axially chiral products with high yields and enantioselectivities. This protocol provides an efficient approach for the facile construction of N−N atropisomers and further expands the range of of N−N axially chiral derivatives. Additionally, under the conditions of electrocatalysis, the desired N−N axially chiral products were also successfully achieved with good to excellent efficiencies and enantioselectivities.

A family of pyridine–oxazoline-ligated cobalt complexes L2CoCl2 3a–h were synthesized and characterized. Determined via single-crystal X-ray diffraction, complexes 3a and 3d, ligated by two ligands, displayed a distorted tetrahedral coordination of a cobalt center. The X-ray structure indicated the pyridine–oxazoline ligands acted as unusual mono-dentate ligands by coordinating only to Noxazoline. Upon activation with AlEt2Cl (diethylaluminum chloride), these cobalt complexes all exhibited high catalytic activity (up to 2.5 × 106 g·molCo−1·h−1), affording cis-1,4-co-3,4-polyisoprene with molecular weights of 4.4–176 kg mol−1 and a narrow Ð of 1.79–3.42, suggesting a single-site nature of the active sites. The structure of cobalt catalysts and reaction parameters, especially co-catalysts and the reaction temperature, all have significant influence on the polymerization activity but not on the microstructure of polyisoprene.

An efficient Cp*Rh(III)-catalyzed direct acylmethylation of 2H-indazoles with sulfoxonium ylides has been realized under air atmosphere via chelation-assisted strategy. This protocol enables a regioselective access to a variety of ortho-acylmethylated 2-phenylindazole derivatives in moderate to good yield, which has the advantages of broad substrate scope, good functional group tolerance, and operational convenience. The H/D exchange experiment reveals that a reversible cleavage of C–H bond might not be the rate-limiting step in this transformation.

Fluorescent chemosensors are powerful imaging tools used in a broad range of biomedical fields. However, the application of fluorescent dyes in bioimaging still remains challenging, with small Stokes shifts, interfering signals, background noise, and self-quenching on current microscope configurations. In this work, we reported a supramolecular cage (CA) by coordination-driven self-assembly of benzothiadiazole derivatives and Eu(OTf)3. The CA exhibited high fluorescence with a quantum yield (QY) of 38.57%, good photoluminescence (PL) stability, and a large Stokes shift (153 nm). Furthermore, the CCK-8 assay against U87 glioblastoma cells verified the low cytotoxicity of CA. We revealed that the designed probes could be used as U87 cells targeting bioimaging.

In recent years, incredible endeavors have been devoted to the design and self-assembly of discrete metal–organic cages (MOCs) with expanding intricacy and functionality. The controlled synthesis of metal–organic supramolecular cages with large branched chains remains an interesting and challenging work in supramolecular chemistry. Herein, a tetrahedral metal–organic supramolecular cage (ZnII4L4) containing 12 dendritic carbazole arms is unprecedentedly constructed through coordination-driven subcomponent self-assembly and characterized in different ways. Interestingly, tetrahedral supramolecular Cage-1 exhibited the potential for aggregation-induced emission (AIE) performance and stimulus-responsive luminescence features, and it achieved color-tunable photoluminescence due to the introduction of dendritic carbazole arms. Crucially, owing to the great photophysical properties of Cage-1 in solution, Cage-1 was enabled to act as a fluorescent ink for the vapor-responsive recording and wiping of information.

Porous organometallic nanomaterials are a new class of materials based on a three-dimensional structure. They have excellent applications in different fields, but their applications in gas storage and separation have not been fully developed. CO2 adsorption storage and hydrocarbon separation has been a challenging industrial problem. Several typical molecular adsorbents have been used to study the separation, but the problems of long-term stability, high selectivity and synthetic complexity of these adsorbents remain to be solved. Here, we have designed and synthesized tetrahedral metal supramolecular nanocage with custom cavities based on the unique rigid structure of triptycene derivatives. Using the unique discrete porous structure of tetrahedral metal nanocages, the gas adsorption and separation performance of the metal supramolecular nanocage was investigated. By analyzing the adsorption and desorption isotherms and the multi-component competitive adsorption curves, we noticed that the tetrahedral supramolecular nanocages had good CO2 storage capacity and good separation capacity for C2H2/CO2 and C2H2/N2. All these indicate that porous organic metal nanomaterials are expected to be a new energy saving separation material.

A cobalt-catalyzed C(sp2)–H alkoxylation of 1-naphthylamine derivatives has been disclosed, which represents an efficient approach to synthesize aryl ethers with broad functional group tolerance. It is noteworthy that secondary alcohols, such as hexafluoroisopropanol, isopropanol, isobutanol, and isopentanol, were well tolerated under the current catalytic system. Moreover, a series of biologically relevant fluorine-aryl ethers were easily obtained under mild reaction conditions after the removal of the directing group.

In the title compound, [Fe(C5H5)(C20H13N2O2)], the substituted cyclopentadienyl ring and quinoline system are approximately coplanar, making a dihedral angle of 5.18 (6)°, while the dihedral angle between the quinoline system and the benzene ring is 28.45 (8)°. There is high thermal motion in the free cyclopentadienyl ring compared with the substituted cyclopentadienyl ring. The conformation of the two cyclopentadienyl rings in the ferrocenyl moiety is eclipsed.

The complete molecule of the title compund, C15H14Br2O2, is generated by the application of crystallographic twofold symmetry, with the central C atom lying on the rotation axis. The dihedral angle between the benzene rings is 62.4 (3)°. In the crystal, short Br...Br contacts [3.4885 (16) Å] occur.

The title compound, C30H23IO2P2S2, was synthesized by the reaction of 2-iodobenzene-1,3-diol, chlorodiphenylphosphine, Et3N and sulfur. The P=S bonds project to opposite sides of the central aromatic ring. The O—P—S and C—P—S bond angles are significantly larger than the O—P—C and C—P—C bond angles, indicating significant distortion of the tetrahedral geometries of the P atoms. The P=S bond lengths of 1.9311 (13) and 1.9302 (12) Å in the title compound are shorter than that found in Ph3P=S [1.950 (3) Å] because the replacement of one C atom attached the P atom by an O atom increases the effective electronegativity of the P atom.

The asymmetric unit of the title compound, C16H14N2, contains two independent molecules in which the dihedral angles between the pyrimidine and naphthaline rings are 38.20 (5) and 39.35 (5)°. Intermolecular C—H...π contacts and π–π stacking interactions [centroid–centroid distances = 3.766 (1) and 3.792 (1) Å] are present in the crystal structure.

In the title compound, C6H7IN2, the non-H atoms of the molecule are located on a crystallographic mirror plane; the H atoms of the methyl groups are therefore disordered over two positions of equal occupancy. In the crystal structure, short intermolecular I...N contacts [3.390 (3) Å] are found, linking the molecules into zigzag chains. In addition, there are intermolecular π–π stacking interactions between the pyrimidine rings of adjacent molecules [centroid–centroid distance = 3.5168 (10) Å], resulting in a two-dimensional supramolecular architecture.

In the title compound, [Fe(C5H5)(C12H12NO)], the dihedral angle between the pyridyl and substituted cyclopentadienyl rings is 23.58 (3)°. The crystal structure is characterized by weak intermolecular C—H...N hydrogen-bonding contacts, leading to the formation of chains running parallel to the n-glide planes. A weak intermolecular C—H...π contact is also present.

In the title compound, [FePdBr(C5H5)(C11H10N2)(C26H36NP)]·CH2Cl2, the Pd atom displays a distorted square-planar coordination environment. The five-membered metallacycle adopts an envelope conformation with the coordinated cyclopentadienyl C atom 0.4222 (4) Å out of plane. The dihedral angle between the pyrimidinyl ring and substituted cyclopentadienyl ring is 21.47 (2)°. In the crystal structure, the dimeric unit is generated through the C—H...π contact via a crystallographic inversion centre, while the C—H...Cl contacts in the dimeric centre link the dichlormethane molecules with the Pd complex molecules.

In the title compound, [Fe(C5H5)(C11H13N4)], the triazolyl and Cp ring form a dihedral angle of 76.6 (3)°. In the crystal structure, there are both intra- and intermolecular C—H...π interactions, forming a one-dimensional chain structure along [010].