Molecular Modeling of poly(p-phenylenevinylene):: Synthesis and photophysical properties of oligomers

A series of oligo(phenylenevinylene)s (OPVs) of different lengths containing aldehyde and dialdehyde groups on the ends were synthesized and characterized. Their photophysical properties were also investigated via ultraviolet-visible, steady-state, and time-resolved fluorescence spectra. The results indicated that the absorption maximum, radiative rate constant, and excitation maximum of an OPVnCHO oligomer series (where n represents the oligomeric length) showed linear relationships with the reciprocal number of conjugated units. Similarly, the absorption maximum and emission lifetime of the oligomers of an OPVn-2CHO series showed linear relationships with the reciprocal number of conjugated units. The dependence of the fluorescence intensities of the OPVs on the concentration of the quencher C-60 was evaluated. Apparently, upon photoexcitation, the OPVs underwent significant fluorescence quenching. The results for different OPV derivatives and a quenching mechanistic discussion showed that the static quenching contribution was indeed responsible for the significant upward curvature. (c) 2007 Wiley Periodicals, Inc.