Covalent organic frameworks (COFs) are an emerging class of crystalline porous organic materials which are fabricated via reticular chemistry. Their topologic structures can be precisely predicted on the basis of the structures of building blocks. However, constructing COFs with complicated structures has remained a great challenge, due to the limited strategies that can access to the structural complexity of COFs. In this work, we have developed a new approach to produce COFs bearing three different kinds of pores. The design is fulfilled by the combination of vertex-truncation with multiple-linking-site strategy. On the basis of this design, a “V”-shaped building block carrying two aldehyde groups on the end of each branch has been synthesized. Condensation of it with 1,4-diaminobenzene or benzidine leads to the formation of two triple-pore COFs, TP-COF-DAB and TP-COF-BZ, respectively. The topological structures of the triple-pore COFs have been confirmed by PXRD studies, synchrotron small-angle X-ray scattering (SAXS) experiments, theoretical simulations, and pore size distribution analyses. Furthermore, for the first time, an in situ COF-to-COF transformation has also been achieved by heating TP-COF-BZ with 1,4-diaminobenzene under solvothermal condition, which leads to the formation of TP-COF-DAB via in situ replacing the benzidine linkers in TP-COF-BZ with 1,4-diaminobenzene linkers.

AbstractAmphiphilic molecules have long been regarded as an important class of supramolecular building blocks for the fabrication of nanomaterials. While most previous researches have mainly focused on amphiphlies with flexible structures, in this work, four novel amphiphiles possessing wholly-rigid skeletons have been designed and synthesized. These molecules were built by using 4,4’-bipyridin-1-ium or viologen as hydrophilic moieties and phenyl or biphenyl as hydrophobic segments, bridged by a pyridazine unit. Their self-assembly behavior has been investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and transmission electron microscopy (TEM), which revealed they could self-assemble into well-ordered nanoarchitectures with various morphologies such as vesicles, micro/nanorods and nanotubes in water or methanol, depending on their hydrophilic/hydrophobic fraction ratios.

Two novel covalent organic frameworks (COFs) bearing Kagome lattices have been fabricated through the condensations of a D2h symmetrical tetraaldehyde and C2 symmetrical aromatic diamines of various lengths.

The topology of a covalent organic framework (COF) is generally believed to be dictated by the symmetries of the monomers used for the condensation reaction. In this context, the use of monomers with different symmetries is usually required to afford COFs with different topologies. Herein, we report a conceptual strategy to regulate the topology of 2D COFs by introducing alkyl substituents into the skeleton of a parent monomer. The resulting monomers, sharing the same C2 symmetry, were assembled with a D2h symmetric tetraamine to generate a dual-pore COF or single-pore COFs, depending on the sizes of the substituents, which were evidenced using PXRD studies and pore size distribution analyses. These results demonstrate that the substituent is able to exert a significant influence on the topology of COFs, which is crucial for their application.

We herein report the construction of a new heteropore COF which consists of two different kinds of micropores with unprecedented shapes. It exists as hollow microspheres and exhibits an extremely high volatile iodine uptake (up to 481 wt%) by encapsulating iodine in the inner cavities and porous shells of the microspheres.

A model system has been established to construct two-dimensional (2D) covalent organic frameworks (COFs) by taking advantage of the variable orientation of imine bonds. During the assembly process, the imine bonds adopt an unprecedented heterodromous orientation to facilitate the formation of the COFs.

It is very important to create novel topologies and improve structural complexity for covalent organic frameworks (COFs) that might lead to unprecedented properties and applications. Despite the progress achieved over the past decade, the structural diversity and complexity of COFs are quite limited. In this Communication, we report the construction of COFs bearing three different kinds of pores through the heterostructural mixed linker strategy involving the condensation of a D2h-symmetric tetraamine and two C2-symmetric dialdehydes of different lengths. The complicated structures of the triple-pore COFs have been confirmed by powder X-ray diffraction and pore size distribution analyses.

Although a lot of covalent organic frameworks (COFs) have been constructed over the past 10 years, the topologies of COFs are still quite limited. In this work, we report one-step construction of a COF with an unprecedented topology from the combination of C3-symmetrical and C2-symmetrical building blocks. It contains two types of triangular micropores of different sizes and chemical environments: one is 11.3 Å and the other is 15.2 Å. The structure of the dual-pore COF was confirmed by powder X-ray diffraction (PXRD) investigation, nitrogen adsorption–desorption study, and theoretical calculations.

Covalent organic frameworks (COFs) are crystalline porous materials bearing microporous or mesoporous pores. The type and size of pores play crucial roles in regulating the properties of COFs. In this work, a novel COF, which bears two different kinds of ordered pores with controllable sizes: one within microporous range (7.1 Å) and the other in mesoporous range (26.9 Å), has been constructed via one-step synthesis. The structure of the dual-pore COF was confirmed by PXRD investigation, nitrogen adsorption–desorption study, and theoretical calculations.

The topology of a covalent organic framework (COF) is generally believed to be dictated by the symmetries of the monomers used for the condensation reaction. In this context, the use of monomers with different symmetries is usually required to afford COFs with different topologies. Herein, we report a conceptual strategy to regulate the topology of 2D COFs by introducing alkyl substituents into the skeleton of a parent monomer. The resulting monomers, sharing the same C2 symmetry, were assembled with a D2h symmetric tetraamine to generate a dual-pore COF or single-pore COFs, depending on the sizes of the substituents, which were evidenced using PXRD studies and pore size distribution analyses. These results demonstrate that the substituent is able to exert a significant influence on the topology of COFs, which is crucial for their application.

A model system has been established to construct two-dimensional (2D) covalent organic frameworks (COFs) by taking advantage of the variable orientation of imine bonds. During the assembly process, the imine bonds adopt an unprecedented heterodromous orientation to facilitate the formation of the COFs.

We herein report the construction of a new heteropore COF which consists of two different kinds of micropores with unprecedented shapes. It exists as hollow microspheres and exhibits an extremely high volatile iodine uptake (up to 481 wt%) by encapsulating iodine in the inner cavities and porous shells of the microspheres.

A strategy to construct covalent organic frameworks (COFs) bearing two different kinds of pores has been developed, by which two dual-pore COFs were fabricated through the condensation reactions of two D2h symmetrical building blocks. The COFs exhibit good adsorption capacities for CO2 and H2.

This paper reports the construction of folded and helical supramolecular structures through the self-assembly of a series of flexible linear donor oligomers induced by a rigid rod-like acceptor template. The donor oligomers were constructed by connecting two, four, six, and eight 1,5-dioxynaphthalene (DAN) units with polyether chains, respectively, and the acceptor template was generated by incorporating 4,4′-bipyridine moieties at the 3,6-positions of a pyridazine skeleton. 1H NMR, UV-vis, and fluorescence spectroscopy studies indicated that the formation of the folded and helical structures was mainly driven by the intermolecular donor–acceptor interactions between the electron-rich DAN units and the electron-deficient template, which was further supported by DFT calculations. It was also found that the strength of the interactions between the donor oligomers and the acceptor template remarkably increased with the elongation of the oligomers.