Science China Chemistry最新文献

For room temperature self-healing triboelectric nanogenerators (TENGs), the inherent contradiction between mechanical strength and self-healing properties was an urgent problem to be solved. Based on the phenol-carbamate bond, this paper proposed a strategy to design a new molecular structure and coordinate the triple dynamic bonds, which provided a feasible strategy to solve this contradiction. With polytetramethylene ether glycol (M_n = 1,000) as the soft segment in the main chain of polyurethane (PU), meanwhile methylene diphenyl diisocyanate and 4,4′-dihydroxybiphenyl (BP) as the hard segment and chain extension agent, respectively, the combination of tetrad benzene ring endowed the resultant 4BP-PU with π-π interaction. The effective reversible dissociation and association with hydrogen bond not only bestowed 4BP-PU with high mechanical strength (16.14 MPa), but also promoted high self-healing efficiency (94.8%) at room temperature. 4BP-PU was selected as the elastic substrate between polydimethylsiloxane and copper sheet to prepare a self-healing TENG to collect energy from natural motion. Consequently, the rational molecular structure design provided new ideas for developing self-healing materials and fabricating energy harvest electronics.

Helical poly(arylacetylene)s have formed an intriguing class of polymers, whose chiralities are dynamic and liable to external stimuli. By combining dendronized polymer topology with dendritic oligoethylene glycols (OEGs), we here report on synthesis of a homologous series of thermoresponsive dendronized poly(arylacetylene)s with either poly(phenyl acetylene) or poly (naphthalene acetylene) as the backbones, and investigate tunability of their helical conformations. These polymers carry dendritic OEG pendants with either methoxyl- or ethoxyl-terminals to tune their unprecedent thermoresponsive behaviors, and at the same time, dendritic shielding plays an important role in mediating their thermal phase transition temperatures. Helicity of these polymers is originated from the chiral alanine or phenylalanine moieties within the dendritic pendants, which can be tailored through manipulating solvation in different organic solvents or via thermal dehydration and collapse in water. Furthermore, achiral additives such as linear or dendritic OEGs and benzene derivatives can act similarly as thermal dehydration to induce chirality transitions of these polymers in aqueous phase through interplay competitions between the additives and the polymers against their hydration.

Hepatocellular carcinoma (HCC) is a highly aggressive liver malignancy and the main form of liver cancer. Early diagnosis and treatment of HCC can effectively reduce mortality. Carboxylesterase (CE)-specific detection and imaging can be used for early diagnosis and image-guided surgical of HCC. However, traditional optical probes suffer from poor selectivity and low imaging signal-to-noise ratio. Here, we have constructed a series of chemiluminescent probes for carboxylesterase detection based on the strategy of enzymatic pocket-oriented steric tailoring techniques. The probes with different unique and excellent properties have been obtained through the structure-based steric hindrance adjustment on the recognition site. Here, CE-2 has been successfully used for high-throughput screening of rapid carboxylesterase inhibitors due to its extremely low detection limit (2.5 × 10⁻⁴ U mL⁻¹) and fast recognition ability. CE-3 has been successfully used for image-guided surgery of orthotopic hepatocellular carcinoma due to its ultra-long chemiluminescence imaging (over 12 h) of hepatocellular carcinoma. This study may promote advances in the rapid detection and screening of inhibitory drugs for CE and the field of surgical navigation in HCC.

Utilizing diverse organic crosslinkers for cyclization has proven to be an effective approach to creating peptide libraries, enabling the rapid discovery of functional peptides. Existing crosslinkers usually provide a tiny and flexible molecular scaffold to constrain peptide conformations, leading to larger cyclic peptides retaining a high degree of flexibility. Moreover, the limited structural impact of the crosslinkers undermines the feasibility of diversifying cyclic peptide structures by varying the types of crosslinker scaffolds. These limitations hamper the robustness of various cyclic peptide libraries for ligands and drug discovery and development. Herein, we present a unique crosslinker featuring a bulky and rigid biphenyl-dihydrothiazole (BDT) scaffold for the rapid and biocompatible cyclization of linear peptides. This scaffold was used to construct phage display BDT-cyclic peptide libraries, enabling the effective identification of cyclic peptide binders with low-nanomolar binding affinity toward BCL-X_L, a protein target with potential for cancer therapy. Thus, this study introduces a novel method for constructing cyclic peptide libraries with rigidly constrained and diverse structures, offering a promising avenue for the de novo discovery of cyclic peptide ligands and drugs.

Rare earth metal-organic frameworks (RE-MOFs) have drawn wide attention owing to diverse network structures and various application prospects. However, due to the unpredictable formation of the nodes, it is still challenging to design novel RE-MOFs. A novel versatile strategy was developed employing a RE-acetate complex (RE₂(CH₃COO)₆·4H₂O) as a precursor to construct RE-MOFs. 2D RE-MOFs (RE-DBP) and 3D RE-MOFs (RE-TCPP) could be obtained by using dicarboxylic porphyrin ligands H₂DBP and tetracarboxylic porphyrin ligands H₂TCPP, respectively. Ten RE-MOFs were further synthesized to verify the universality of the methodology. Highly crystalline RE-MOFs could also be prepared at room temperature via the developed strategy, which could significantly promote large-scale preparation and practical application of RE-MOFs. As proof of the concept, the performance of porphyrin-based RE-MOFs was investigated in the photocatalytic cycloaddition of CO₂ with epoxides. Among the RE-DBP(Co) MOFs, Tb-DBP(Co) exhibited the best photocatalytic performance, which was also greater than that of the corresponding 3D MOF Tb-TCPP(Co) due to the optimal 2D structure and thus the accelerated photogenerated charge separation and transfer process. This work not only provides a novel versatile strategy to design and develop RE-MOFs, but also proposes a promising approach for the potential bulk production of RE-MOFs at room temperature.

Electrochemical CO₂ reduction reaction (CO₂RR) has been regarded as one of the most promising solutions to achieving “zero carbon emission”. In most of the CO₂RR-related studies, high-purity CO₂ has been employed as the feed gas; however, in practice, CO₂ is generally emitted in low concentrations, so it is of great significance to realize high-selectivity electroreduction of low-concentration CO₂ with large concentration fluctuation. In this work, we constructed a dual-active-site catalyst and successfully achieved CO₂ local enrichment and conversion for low-concentration CO₂. Operando experiments reveal that the catalyst has one type of site for activating CO₂ and one type of site for binding the reaction intermediates. The dual-active-site catalyst displays a selectivity for formic acid consistently above 97% over a broad potential window (from −0.9 to −1.6 V vs. RHE). Even when fed with a low-concentration CO₂ stream (volume ratio from 50% down to 10%), the dual-active-site catalyst could display high activity and selectivity (>91%). In particular, the selectivity is still above 85% when the CO₂ volume ratio is as low as 5%. This work offers a feasible route for converting low-concentration CO₂ via a synergistic effect for dual-active-site catalysts.