Theoretical investigation on the white-light emission from a single-polymer system with simultaneous blue and orange emission (Part II)

4-alkoxyethoxy-N-octadecyl-1,8-naphthalimide fluorescent sensor for human serum albumin and other major blood proteins: design, synthesis and solvent effect

A series of 4-alkoxyethoxy-N-octadecyl-1,8-naphthalimides with intense blue fluorescence were designed and synthesized as polarity and spectrofluorimetric probes for the determination of proteins. In solvents of different polarities, the Stokes shifts of two dyes increased with increasing solvent polarity and fluorescence quantum yields decreased significantly, suggesting that electronic transiting from ground to excited states was π-π(*) in character. Dipole moment changes were estimated from solvent-dependent Stokes shift data using a solvatochromic method based on bulk solvent polarity functions and the microscopic solvent polarity parameter (E(T)N). These results were generally consistent with semi-empirical molecular orbital calculations and were found to be quite reliable based on the fact that the correlation of the solvatochromic Stokes shifts with E(T)N was superior to that obtained using bulk solvent polarity functions. Fluorescence data revealed that the fluorescence quenching of human serum albumin (HSA) by dyes was the result of the formation of a Dye-HSA complex. The method was applied to the determination of total proteins (HSA + immunoglobulins) in human serum samples and results were in good agreement with those reported by the research institute.

ELECTRON-WITHDRAWING SUBSTITUTED BTD-BASED DERIVATIVE: ELECTRONIC AND OPTICAL PROPERTIES, CHARGE TRANSFER, STABILITY STUDY

To provide guidelines for designing new functional materials in organic light emitting diodes, the effect of the electron-withdrawing substitution on the electronic, optical, charge transport properties, and stability of 2,1,3-benzothiadiazole (BTD)-based derivative has been investigated on the basis of the quantum chemical calculations. The results show that introduction of the electron-withdrawing group on terminal N, N-disubstituted amino unit causes the absorption and emission wavelength maxima shift to shorter wavelength relative to the pristine molecule. In addition, the reorganization energies of designed BTD-based derivatives are calculated to investigate their charge carrier properties. The electrostatic surface potentials of investigated derivatives are calculated to evaluate their stabilities.