Pore-Directed Solid-State Selective Photoinduced E-Z Isomerization and Dimerization Within Metal-Organic Frameworks

Design and construction of suitable pore microenvironments for selective catalytic reactions of small guest molecules is a major goal for chemists. Herein, we report control of competitive E-Z photoisomerization and photodimerization within porous metalorganic frameworks (MOFs) by fine-tuning the pore microenvironments using different dicarboxylate linkers. MOFs with small pores ((E)-XMOF 1 and (E)X-MOF1') favor the photoinduced E-Z isomerization of one encapsulated diaryl alkene substrate while those with large pores (((E)-X)2MOF(2)) prefer the photodimerization of two encapsulated alkene substrates. Both reactions show broad functional group compatibility and proceed stereospecifically in good yields under mild conditions. High local concentration of diaryl alkene ligands and their preorientation within pores facilitate stereoselective dimerization. This pore engineering strategy is applicable to control and create pore microenvironemnts for other photoinduced organic reactions within porous MOFs. [GRAPHICS] .