Alkynylpyrenes as improved pyrene-based biomolecular probes with the advantages of high fluorescence quantum yields and long absorption/emission wavelengths.

The photochemical properties of various alkynylpyrene derivatives have been investigated in detail with a view to developing a new class of pyrene-based biomolecular probes. The absorption maxima of the alkynylpyrenes were seen to be shifted to longer wavelengths compared with those of the unsubstituted parent pyrene. Fluorescence quantum yields of the alkynylpyrenes dramatically increased up to 0.99 in ethanol, and only slight quenching of the fluorescence occurred even under aerated conditions. The alkynylpyrenes have been successfully introduced into representative biomolecules such as peptides, proteins, and DNAs. The detectabilities of the labeled biomolecules were significantly improved, with the unique photochemical characteristics of the pyrene nucleus being maintained.