Effect of CH₃OH on the luminescent properties of the [Zn(sfdb)(bpy)(H₂O)]_n·0.5nCH₃OH metal-organic framework

The influence of CH₃OH solvent on the luminescent properties of the [Zn(sfdb)(bpy)(H₂O)]_n·0.5nCH₃OH (sfdb = 4,4-sulfonyldibenzoic acid, bpy = 2,2-bipyridine) metal-organic framework (MOF) was investigated by considering the hydrogen bond between CH₃OH and [Zn(sfdb)(bpy)(H₂O)]_n in an electronically excited state using density functional theory and time-dependent density functional theory methods. The calculated geometry, infrared spectrum, and UV-vis spectrum in the ground state are consistent with the experimental results. The frontier molecular orbitals and electronic configuration indicated that the origin of the luminescence is ligand-to-ligand charge transfer rather than ligand-to-metal charge transfer, as has been previously proposed. Wefound that the O3⋯H11 hydrogen bond is weaker in the excited state than in the ground state, and the weaker hydrogen bond in the electronically excited state should enhance the luminescence. The results show that the CH₃OH solvent changes the luminescence properties of [Zn(sfdb)(bpy)(H₂O)]_n, which provides potential opportunities for the design of diverse luminescent MOFs.