ATTO 647N belongs to a new generation of fluorescent labels for the red spectral region. Characteristic features of the label are strong absorption, high fluorescence quantum yield, high thermal and photostability, exceptionally high stability towards atmospheric ozone and only little triplet formation. In common with most dye labels, absorption and fluorescence are independent of pH, at least in the range of pH 4 to 11, used in typical applications.

ATTO 647N and its derivatives are supplied as solvent-free perchlorate salts. The dye is moderately hydrophilic. Its NHS-ester and maleimide show excellent solubility in polar solvents like DMF, DMSO or acetonitrile. For details of coupling see our recommended labeling procedure (PDF). The fluorescence is excited most efficiently in the range 625 - 660 nm. A suitable excitation source is, for instance, the 647 nm line of the Krypton-Ion laser or a Diode-Laser emitting at 650 nm.

As supplied the dye consists of a mixture of two diastereomers with practically identical absorption and fluorescence properties.