Designing energetic covalent organic frameworks for stabilizing high-energy compounds

As an emerging high-energy compound,3-nitro-1,2,4-triazol-5-one(NTO)is used in military explosives and rocket propellants.However,the strong acidic corrosion of NTO,and the high sensitivity and poor thermostability of its salts,severely restrict their practical applications.Therefore,a novel strategy to design and construct energetic covalent organic frameworks(COFs)is proposed in this study.We have successfully prepared a two-dimensional crystalline energetic COF(named ECOF-1)assembled from triaminoguanidine salt,in which NTO anions are trapped in the porous framework via the ionic interaction and hydrogen bonds.The results show that ECOF-1 exhibits superior thermal stability than energetic salt of NTO.It also exhibits insensitivity and excellent heat of detonation of 7,971.71 kJ·kg−1.ECOF-1 greatly inhibits the corrosiveness of NTO.In prospect,energetic COFs are promising as a functional platform to design high-energy and insensitive energetic materials.

Self-assembly of anthraquinone covalent organic frameworks as 1D superstructures for highly efficient CO_(2) electroreduction to CH_(4)

The design of selective and efficient covalent organic frameworks(COFs)based electrocatalysts with tunable morphology for efficient CO_(2) reduction reaction(CO_(2)RR)to CH_(4) is highly desirable.Here,two kinds of anthraquinone-based COFs(i.e.,AAn-COF and OH-AAn-COF)with tunable 1D superstructures(e.g.,nanofibers(NF)and hollow tubes(HT))have been produced via Schiff-base condensation reaction.Interestingly,a rarely reported nanosheet-based self-template mechanism and a nanosheet-crimping mechanism have been demonstrated for the production of COF-based nanofibers and hollow tubes,respectively.Besides,the obtained COF-based superstructures can be post-modified with transition metals for efficient CO_(2)RR.Specifically,AAn-COF-Cu(NF)and OH-AAn-COF-Cu(HT)exhibit superior faradaic-efficiency with CH_(4)(FECH_(4))of 77%(-128.1 mA cm^(-2),-0.9 V)and 61%(-99.5 mA cm^(-2),-1.0 V)in a flow-cell,respectively.Noteworthy,the achieved FECH_(4) of AAn-COF-Cu(NF)(77%)is the highest one among reported crystalline COFs.This work provides a general methodology in exploring morphology-controlled COFs for electrocatalytic CO_(2)RR.

Predicting of Covalent Organic Frameworks for Membrane-based Isobutene/1,3-Butadiene Separation:Combining Molecular Simulation and Machine Learning

Efficient separation of C4 olefins is of critical importance and a challenging task in petrochemical industry. Covalent organic frameworks(COFs) could be used as promising candidates for membrane-based isobutene/1,3-butadiene(i-C4H8/C4H6) separation. Owing to large amounts of COFs appearing, however, the rapid prediction of optimal COFs is imperative before experimental efforts. In this work, we combine molecular simulation and machine learning to study COF membranes for efficient isolation of i-C4H8 over C4H6. Using molecular simulation, four potential COF membranes, which possess both high membrane performance score (MPS) value and moderate membrane selectivity were screened out and the mechanism of membrane separation further revealed is an adsorption dominated process. Further, random forest(RF) model with high prediction accuracy(R2>0.84) was obtained and used for elucidating key factors in controlling the membrane selectivity and i-C4H8 permeability. Ultimately, the optimal COF features were obtained through structure-performance relationship study. Our results may trigger experimental efforts to accelerate the design of novel COFs with better i-C4H8/C4H6separation performance.

Copper(Ⅱ) ions-immobilized virus-like hollow covalent organic frameworks for highly efficient capture and sensitive analysis of amyloid beta-peptide 1–42 by MALDI-MS

Amyloid beta-peptide 1-42(Aβ1-42)is one of the biomarkers of Alzheimer's disease,and its selective capture and quantitative detection are important for diagnosis and treatment of Alzheimer's disease.Herein,copper(Ⅱ)ions-immobilized virus-like hollow covalent organic frameworks(V-HCOFs@Cu^(2+))were synthesized by a facile approach.The as-prepared V-HCOFs@Cu^(2+)showed unique morphology,ultra-high specific surface(2552 m^(2)/g),uniform mesoporous structure(3.2 nm),superior chemical stability and abundant binding sites.Based on these excellent properties,the V-HCOFs@Cu^(2+)could be adopted as an ideal enrichment probe for highly efficient capture of Aβ1-42,exhibiting high adsorption capacity(320 mg/g),and fast adsorption equilibration time(3 min).In addition,an attractive approach of the V-HCOFs@Cu^(2+)-based matrix-assisted laser desorption/ionization mass spectrometry(MALDI-MS)was developed for the rapid screening and quantitative analysis of Aβ1-42 in human serum by using C-peptide as an internal standard,which exhibited low limit of detection(LOD,0.2 fmol/μL),and satisfactory recovery.This work provides an alternative solution for enrichment of biomarkers and also offers the potential applications of COFs in clinical analysis.

基于金纳米颗粒/共价有机骨架COF-TpPa-1无标记型C-反应蛋白免疫传感器的研制

采用高温溶剂热法合成了共价有机框架材料(COF-TpPa-1),通过还原法将金纳米颗粒负载到COF-TpPa-1材料上,制得了Au NPs/COF-TpPa-1纳米材料,并将其作为固定基质来固定CRP抗体,制备了无标记型C-反应蛋白(CRP)免疫传感器。修饰在电极上的Au NPs/COF-TpPa-1可直接催化对硝基苯酚的还原,当CRP抗体与抗原结合后,阻碍了电极表面的电子传递速率,使得检测电流减小,通过电流与抗原浓度之间的关系,实现对CRP的检测。线性范围为0.01~150 ng/mL,检测下限为3 pg/mL,相关系数为0.9980。该传感器检测下限低,灵敏度高,方法简便。

手性共价有机骨架掺杂有机聚合物毛细管整体柱的制备及表征

采用1,3,5-三甲酰间苯三酚和二乙酰-L-酒石酸酐在无水四氢呋喃反应生成手性有机单体CTp,继而与对苯二胺在无水乙醇和无水四氢呋喃的条件下反应,生成手性共价有机骨架CTpPa-1。以制得的CTpPa-1为手性功能单体,十二烷醇和环己醇为二元制孔剂,甲基丙烯酸缩水甘油酯为非手性功能单体,2,2-偶氮二异丁腈为引发剂,乙二醇二甲基丙烯酸酯作为交联剂在内径75μm的毛细管中进行缩合反应,最终制备出手性CTpPa-1毛细管整体柱。通过X射线衍射、红外光谱对CTpPa-1进行了表征、通过红外光谱、扫描电子显微镜对手性CTpPa-1毛细管整体柱进行了表征,探究了整体柱固定相的组成、形貌。实验结果表明,手性CTpPa-1毛细管整体柱可以承受高压,不会在流动相作用下坍塌,具有较好的通透性。