Stepwise synthesis and characterization of oligomers based on 1,1′-binaphthol with 3,3′-acetylene spacer

A selective mono de-iodination led to an alternative preparation of a mono-iodo binaphthol-derivative in high yield. With the mono-iodo compound, several structurally well-defined, 1,1'-binaphthol-based optically active oligomers with a 3,3'-acetylene spacer were synthesized through palladium catalyzed, stepwise-coupling methods. The electrical and photo-physical properties of the oligomers have been examined. The electrical; photo-absorption, excitation and fluorescent data for various oligomers indicated that there is a very limited conjugation present between the naphthylene rings. The atropic of 1,1'-binaphthyl moiety led to twist and rigid main chain in the oligomers and;polymers. With the changes of the external environment such as solvents, solvent viscosity and ambient temperature, the wavelengths of absorption and fluorescence and the intensities of absorption are changed slightly, but the fluorescent intensity and quantum yield can be influenced. The luminescent behaviors of the longer chain oligomer exhibit the twisted intramolecular charge transfer characteristic, which has a potential application in wavelength-stable light emitting material adaptable to ambient temperature and the solvent used in wide range. (C) 1998 Elsevier Science Ltd. All rights reserved.