Recent progress in host–guest metal–organic frameworks: Construction and emergent properties

• The design principles and synthesis strategies of host–guest MOFs is logically reviewed. • The properties and applications of host–guest MOFs originating from synergistic effect are demonstrated. • Further development of host–guest MOFs is suggested. Metal–organic frameworks (MOFs) as a class of unique porous crystalline materials have developed rapidly in the past decades. The unique features of component diversities, structural designability, and tunable porosities of MOFs endow them inherent superiorities as hosts to accommodate diverse species of guests. The resulting host–guest MOFs reveal a variety of properties and applications, which could be readily modulated through the tuning of the host, the guest, and the host–guest interactions. Therefore, the host–guest MOFs have attracted much attention and become a hot topic for research. This review will concentrate on the recent progress of host–guest MOFs. The achievements and understanding of host–guest MOF, including the components of host–guest systems, the types of species interactions, and the characterization methods have been reviewed and discussed. Based on this, the design and tuning principles for the construction of host–guest MOFs have been highlighted. The recently typical examples of function-oriented construction of host–guest MOF for various properties including optical, electrical, and catalytic properties have been overviewed. Furthermore, the challenges and perspectives of developing host–guest MOF materials have been generalized.