Template‐Directed Approach Towards the Realization of Ordered Heterogeneity in Bimetallic Metal–Organic Frameworks

Controlling the arrangement of different metal ions to achieve ordered heterogeneity in metal–organic frameworks (MOFs) has been a great challenge. Herein, we introduce a template‐directed approach, in which a 1D metal–organic polymer incorporating well‐defined binding pockets for the secondary metal ions used as a structural template and starting material for the preparation of well‐ordered bimetallic MOF‐74s under heterogeneous‐phase hydrothermal reaction conditions in the presence of secondary metal ions such as Ni²⁺ and Mg²⁺ in 3 h. The resulting bimetallic MOF‐74s were found to possess a nearly 1:1 metal ratio regardless of their initial stoichiometry in the reaction mixture, thus demonstrating the possibility of controlling the arrangement of metal ions within the secondary building blocks in MOFs to tune their intrinsic properties such as gas affinity.     

Construction of Covalent‐Organic Frameworks (COFs) from Amorphous Covalent Organic Polymers via Linkage Replacement

Covalent‐organic frameworks (COFs) as porous crystalline materials show promising potential applications. However, developing facile strategies for the construction of COFs directly from amorphous covalent organic polymers (COPs) is still a great challenge. To this end, we report a novel approach for easy preparation of COFs from amorphous COPs through the linkage replacement under different types of reactions. Four COFs with high crystallinity and porosity were constructed via the linkage substitution of polyimide‐linked COPs to imine‐linked COFs as well as imine‐linked COPs to polyimide‐linked COFs. The realization of the linkage substitution would significantly expand the research scope of COFs.     

Three‐Dimensional Anionic Cyclodextrin‐Based Covalent Organic Frameworks

Three‐dimensional covalent organic frameworks (3D COFs) are promising crystalline materials with well‐defined structures, high porosity, and low density; however, the limited choice of building blocks and synthetic difficulties have hampered their development. Herein, we used a flexible and aliphatic macrocycle, namely γ‐cyclodextrin (γ‐CD), as the soft struts for the construction of a polymeric and periodic 3D extended network, with the units joined via tetrakis(spiroborate) tetrahedra with various counterions. The inclusion of pliable moieties in the robust open framework endows these CD‐COFs with dynamic features, leading to a prominent Li ion conductivity of up to 2.7 mS cm⁻¹ at 30 °C and excellent long‐term Li ion stripping/plating stability. Exchanging the counterions within the pores can effectively modulate the interactions between the CD‐COF and CO₂ molecules.