Solvent mediated photoluminescence responses over mixed-linker cadmium (II) based metal–organic frameworks

Subtle change of solvothermal condition afforded two structurally diverse mixed-linker cadmium-based metal-organic frameworks (MOFs) with remarkable luminescence property. Single MOF being responsive towards both “turn on” and turn off” type of responses selectively with specific solvent has rarely been reported previously. Three dimensional mixed-linker cadmium based metal–organic framework (MOF), [Cd 2 (L 1 ) 2 (L 2 ) 0.5 (H 2 O)] n ( 1 ) and {[Cd 3 (L 1a ) 2 (L 2 ) 2 ]⋅H 2 O} n ( 2 ) (L 1 = pyrazole-3,5 dicarboxylate, L 1a = pyrazolate-3,5 dicarboxylate and L 2 = 4,4′-azopyridine) have been synthesized by solvothermal methods. Notably, subtle change in reaction conditions afforded two strikingly different MOFs. Compounds have been characterized structurally by single-crystal X-ray analysis. Both the compounds feature a pillared-layer framework structure. Photoluminescence properties of the framework compounds have been investigated in the solid state as well as in solvent dispersed medium. Interestingly, solvent specific turn-on/turn-off photo-luminescence responses have been observed for both the compounds ( 1 ) and ( 2 ).