Two isostructural Zn/Co-MOFs with penetrating structures: multifunctional properties of both luminescence sensing and conversion of CO 2 into cyclic carbonates.

Two new metal-organic frameworks (MOFs), namely, {[Zn(HL)(bpea)]·DMF} n (Zn-MOF-1) and {[Co(HL)(bpea)]·DMF} n (Co-MOF-2) (H 3 L = 3-(3,5-dicarboxybenzyloxy)benzoic acid, bpea = 1,2-di(pyridyl)ethane), were obtained by the reaction of H 3 L and N-containing ligand bpea with Zn(NO 3 ) 2 ·6H 2 O and Co(NO 3 ) 2 ·6H 2 O, respectively. The isomorphic Zn-MOF-1 and Co-MOF-2 featured a 3D penetrating framework with different stabilities, luminescence, and catalytic properties. Luminescence measurement indicated that Zn-MOF-1 could be used to detect Al 3+ through a turn-on effect with a detection limit of 0.42 μM. The sensing mechanism experiments showed that the enhanced luminescence of Zn-MOF-1 toward Al 3+ may be due to the weak interaction between Al 3+ and Zn-MOF-1 and the absorbance-caused enhancement (ACE) mechanism. Meanwhile, both Zn-MOF-1 and Co-MOF-2 showed interesting CO 2 adsorption properties and could catalyze the cycloaddition of CO 2 to epoxides resulting in 96 and 92% ideal products within 12 hours, respectively. They can be cycled up to 5 times without significant loss of catalytic efficiency.