Figure 5. Molecular orbital energy diagram for Zn-MOF-nitrobenzene showing the vertical electronic transitions for the maxima absorption band at B3LYP/def2-TZVPP theoretical level
Guang‐Yue and Ke‐Li in 2018 highlight that the host-guest interaction can be generated and that some molecular orbitals of guests appear located between the molecular orbitals involved in the emissive state, for that reason, radiative deactivation is blocked, resulting in the Turn-off .57 In this sense, our results indicated that when nitrobenzene is confined into the Zn-MOF is generates a mixture of states of Zn-MOF and nitrobenzene. In the Zn-MOF-nitrobenzene is observed that the analyte-centered molecular orbital corresponds to the LUMO, while the orbitals just above the LUMO are orbitals located on the BYP linker, which represent the molecular orbitals that correspond to the emissive states in analyte-free Zn-MOF, see Figure 6.