Construction of MOF-74 analogues through pre-installation of functional ligands: efficient directional functionalization and properties

Abstract

Metal–organic frameworks (MOFs) have garnered significant interest owing to their tunable structures and versatile properties. In this study, the construction of MOF-74 analogues based on pre-installation of functional ligands has been investigated. Five distinct ligands and their corresponding complexes are synthesized and characterized. The ligands are strategically designed to impart specific functional groups, enabling enhanced reactivity and tailored properties. Building upon the previously synthesized compounds, an efficient method for the directional functionalization of MOF-74 analogues under moderate conditions has been outlined. This method involves pre-installation through directive substitution of the ligands with suitable functional groups viz. –F, –Br, –I, –CH₃ and –CN, allowing precise control over the resulting MOF's properties and functionalities. The study presents the characteristics and properties of [Cu(L¹)]_n (1), [Cu(L³)]_n (2), [Cu(L⁴)]_n (3), [Cu(L⁵)]_n (4) and [Cu(L⁶)]_n (5) complexes, highlighting their distinct features and potential applications. The findings from this research contribute to the fundamental understanding of MOF-74 analogues' synthesis and the efficient functionalization of these materials. The outlined methodology opens new avenues for the tailored design of MOFs with desired properties, enabling their potential utilization in diverse applications, such as catalysis, gas storage and luminescence sensing properties.