A novel 1,8-naphthalimide probe: synthesis and interactions with nucleic acid and its precursor

Three novel, water-soluble N-substituted 1,8-naphthalimides as the spectroscopic probes of nucleic acid, N-(2-hydroxyethyl)-1,8-naphthalimide (NI1), 1,8-naphthalimide-N-acetic acid (NI2) and 1,8-naphthalimide-N-caproic acid (NI3), were synthesized and photophysically characterized. The steady-state fluorescence quenching of the NI probes with nucleic acids (NA) and their precursors (nucleobases and nucleosides) were studied by Stern–Volmer correlation. The rate constants for bimolecular quenching were obtained in Tris buffer solution. The transient absorption spectroscopy by nanosecond laser flash photolysis were explored to identify the transient species and to determine the kinetics. The dynamic interaction mechanism was attributed to electron transfer (ET) and energy transfer via ³NI.