Solvatofluorochromism of N-[2-(2-hydroxylethylamino)-ethyl]-1,8-naphthalimide in protic solvent
摘要:
A N-substituted naphthalimide derivative N-[2-(2-hydroxylethylamino)-ethyl]-1,8-naphthalimide (HEAN), which contains potential acceptors for hydrogen bond, was synthesized and fully characterized. The fluorescence and UV/vis behaviors of HEAN in different solvents were investigated, and its Stokes shift value and fluorescence quantum yield (Phi(f)) in each solvent were determined. A remarkable fluorescence enhancement of HEAN in protic-polar solvents but a great quenching effect in apolar, less-polar and aprotic-polar solvents were observed, suggesting the key role of the proticity of solvents. In the protic-polar solvents, the fluorescence intensity and the quantum yield of HEAN increased along with a slight red-shift of the characteristic emission wavelength (lambda(em)) with the increase of solvent polarity. Maximum Or value of 0.453 for HEAN was found in water solvent with a Stokes shift of 4636 cm(-1). The inhibition of the photoinduced electron transfer (PET) by the intermolecular hydrogen-bonding interactions between protic solvents and HEAN was proposed to be responsible for its strong fluorescence enhancement. Such solvatofluorochromic property of HEAN may make it as a prospective fluorescent chemosensor to distinguish a protic solvent from aprotic solvents. (c) 2008 Elsevier B.V. All rights reserved.