A sensor for formaldehyde detection: luminescent metal-organic framework [Zn2(H2L)(2,2′-bpy)2(H2O)]n

Density functional theory and time-dependent density functional theory methods have been used to investigate the hydrogen bonding between the Metal-organic framework [Zn-2(H2L)(2,2'-bpy)(2)(H2O)](n) and formaldehyde in the electronically excited state. The calculated geometric configuration, H-1 NMR chemical shift and IR spectra of the hydrogen-bonded complex demonstrated that the hydrogen bond was strengthened in the excited state S-1. The strengthening of the hydrogen bond in the S1 state would lead to a luminescence decreasing phenomenon of [Zn-2(H2L)(2,2'-bpy)(2)(H2O)](n), and the fluorescent rate constant of [Zn-2(H2L)(2,2'-bpy)(2)(H2O)](n) was decreased when encapsulating formaldehyde into it. Taken together, these results indicated that [Zn-2(H2L)(2,2'-bpy)(2)(H2O)](n) could be used for the detection of formaldehyde.