Hydrogen-bonding study of photoexcited 4-nitro-1,8-naphthalimide in hydrogen-donating solvents

Abstract

Abstract:The solute-solvent interactions of 4-nitro-1,8-naphthalimide (4NNI) as a hydrogen bond acceptor in hydrogen donating methanol (MeOH) solvent in electronic excited states were investigated by means of the timedependent density functional theory(TDDFT). We calculated the S 0 state geometry optimizations, electronic transition energies and corresponding oscillation strengths of the low-lying electronically excited states for the isolated 4NNi and hydrogen-bonded 4NNi-(MeOH) 1,4 complexes using the density functional theory (DFT) and TDDFT methods. The electronic excitation energies of the hydrogen-bonded complexes are correspondingly decreased compared to that of the isolated 4NNi, which revealed that the intermolecular hydrogen bond C=O· · · H-O and N=O· · · H-O in the hydrogen-bonded 4NNi-(MeOH) 1,4 are strengthened in the electronically excited state. The calculated results are consistent with the mechanism that hydrogen bond strengthening will induce a redshift of the corresponding electronic spectra, while hydrogen bond weakening will cause a blueshift. Furthermore, we believe that the deduction we used to depict the trend of the hydrogen bond changes in excited states exists in many other fluorescent dyes in solution.

Spectroscopic and Biological Properties of the 3-Imino-1,8-naphthalimide Derivatives as Fluorophores for Cellular Imaging

“…The experiments also showed that the interactions between the ImNIDs and the presence of a polar compound (DMSO) affected the emission properties. Based on the above considerations, it can be concluded that the ability of 1,8-naphthalimide derivatives to form intermolecular interactions might significantly affect the photophysical properties of the system, which has also been considered in other works [40,41].…”