Spectroscopic studies of the excited-state intramolecular proton and electron transfer processes of methyl benzoate derivatives in cucurbit[7]uril nanocage

Insight into Molecular Interactions of Two Methyl Benzoate Derivatives with Bovine Serum Albumin

“…As expected, fluorescence decay profile of II recorded in the absence of BSA consists of a slow decay τ 2 = 0.8 ns as a major component (76%) with a small contribution of a fast decay component ( τ 1 = 200 ps, A 1 = 24%). According to our previous works [ 35 , 37 ], we can state that the slow component can be assigned to the emission from ESIPT state, whereas the decay time of the fast component originates from the emission of LE state.…”

“…In our previous paper, the mechanism of supramolecular solvation dynamics of the methyl benzoate derivatives in aqueous solution with CB[7] has been investigated according to the procedure described by Maroncelli and Fleming [ 37 , 39 , 40 ]. We have shown that solvation dynamics which occurs in subpicosecond time scale in neat solvents of different polarities is slowed down significantly when organic molecule is relocated to CB[7] cavity.…”

“…The interaction of I and II with the model transport protein BSA is studied using steady-state and state-of-the-art time-resolved spectroscopic techniques, which proved to be helpful in understanding the mechanisms of the processes leading to the formation of a stable small organic molecule-protein complexes (quenching, binding and thermodynamic parameters). Overall, our current (in combination with our previous) studies offer a detailed outlook into the dynamic and structural aspects of chemical (CDs, cucurbit[7]urils) [ 33 , 34 , 35 , 36 , 37 ] and biological (BSA) host–guest interactions. Especially, we investigate the effects exerted by biological and chemical nanocavity on the excited-state intramolecular proton and electron transfer processes that may occur in supramolecular systems.…”

“…We have recently undertaken spectroscopic investigations of the some methyl benzoate derivatives which, on the one hand, are interesting from the spectroscopic point of view (they are capable of exhibiting Twisted Intramolecular Charge Transfer- and/or Excited State Intramolecular Proton Transfer-type behaviour) and, conversely, they have potential in applications e.g., TICT and ESIPT fluorescence probes, metal ion sensors, active materials in dry xerographic toners or lasing medium in proton transfer lasers [ 28 , 29 , 30 , 31 , 32 ]. Our scientific attention has been focused not only on the description of the TICT and ESIPT processes of organic molecules in different organic solvents and heterogeneous systems, but also in aqueous solution in the presence of the supramolecular compounds (α-, β- and γ-cyclodextrins, cucurbit[7]uril) [ 33 , 34 , 35 , 36 , 37 ]. We have shown that photochemical and photophysical properties of investigated molecules encapsulated in macrocyclic host macrocyclic host are significantly different from those observed in bulk solution.…”

“…These significant changes in spectroscopic behaviours were attributed to the formation of stable 1:1 and/or 1:2 inclusion complexes. The effect of macrocyclic host complexation on TICT and ESIPT photochemistry has been interpreted in terms of the protection of the embedded organic molecule in host cavity from the neighbouring water molecules (reduction of hydrogen bonds upon encapsulation), size and shape of macrocyclic host, orientation of the guest molecule in micropockets, restriction on molecular motion and the reduced polarity effect introduced by cavities as compared to the aqueous phase [ 33 , 34 , 35 , 36 , 37 ].…”