A family of luminescent metal–organic frameworks: synthesis, structure, and sensing studies

Abstract

Herein we report three novel luminescent metal–organic frameworks (MOFs) viz. [Co(bpeb)(hfipbb)_0.5]_n (LCo-1), [Zn(bpeb)₂(hfipbb)]_n (L-Zn) and [Co(bpeb)₂(oba)]_n (LCo-2) (where bpeb, hfipbb and oba represent (1,4-bis[2-(4-pyridyl)ethynyl]benzene), 4,4′-(hexafluoroisopropylidene)bis(benzoic acid) and 4,4¹-oxybis(benzoic acid) respectively), which were synthesized through the solvothermal method and characterized by SC-XRD. Compounds LCo-1 and L-Zn adopt two-dimensional layered structures while compound LCo-2 is a 3-dimensional framework. The observed dimensionality changes of LCo-1 and LCo-2 from 2D to 3D are due to the different bridging modes of carboxylic acid ligands. In LCo-1 and L-Zn, the hfipbb ligand coordinates to the metal center in a monodentate fashion {(κ¹)-(κ¹)-(κ¹)-(κ¹)-μ₄}, and in LCo-2, dba coordinates in a {(κ¹)-(κ¹)-μ₂} manner. Photoluminescence studies reveal that all three compounds show interesting sensing behavior towards nitroaromatic compounds.