A time-dependent density functional theory study on the effect of electronic excited-state hydrogen bonding on luminescent MOFs

We have investigated a new silver-based luminescent metal-organic framework (MOF) using density functional theory and time-dependent density functional theory methods. We theoretically demonstrated that the H center dot center dot center dot O hydrogen bond is strengthened and the Ag-O coordination bond is shortened significantly due to strengthening of the hydrogen bond in the S-1 state. When the hydrogen bond is formed, the mechanism of luminescence changes from a ligand-to-metal charge transfer (LMCT) coupled with intraligand charge transfer (LLCT) to LMCT, and the luminescence is found to be enhanced.