A Novel Multifunctional Cd-MOF Containing Thiazolo[5,4-d]thiazole and Azo Moieties for Highly Efficient Adsorption of Iodine and Catalytic CO2 Cycloaddition

A novel complex, {[Cd(NO3)(4,4′-Azo)0.5(DPTzTz)]·DMF}n (MOF-1), was obtained by assembling photoactive ligand 2,5-di(pyridin-4-yl)thiazolo[5,4-d]thiazole (DPTzTz) and azo-functionalized dicarboxylic acid linker (4,4′-azodibenzoic acid = 4,4′- H2Azo) under solvothermal conditions. MOF-1 bears a 2-fold interpenetrated 3D framework with 1D open channels. The channel wall was decorated with Lewis acidic Cd(II) center and Lewis basic groups (N═N, TzTz). The title complex exhibited excellent thermal stability and robust chemical stability. After activation, the sample (MOF-1a) can act as a heterogeneous catalyst for the CO2 cycloaddition reaction under mild conditions. Moreover, it can encapsulate 680.1 mg·g–1 and 737.2 mg·g–1 iodine in the vapor phase and in cyclohexane solution (320 mg·L–1), respectively. MOF-1a shows easy recovery and reuse without an obvious decrease of catalytic activity and adsorption capacity. Therefore, MOF-1 is a multifunctional and stable material for iodine adsorption and catalytic CO2 cycloaddition.