Fluorescent phenyl xanthene dyes are described that comprise any
fluorescein, rhodamine or rhodol comprising a particular C9 phenyl ring.
One or both of the ortho groups on the lower C9 phenyl ring is ortho
substituted with a group selected from alkyl, heteroalkyl, alkoxy, halo,
haloalkyl, amino, mercapto, alkylthio, cyano, isocyano, cyanato,
mercaptocyanato, nitroso, nitro, azido, sulfeno, sulfinyl, and sulfino.
In one embodiment, halo and/or hydroxy groups are used. Optimal dyes
contain a lower C9 phenyl ring in which both ortho groups are the same
and the lower ring exhibits some form a symmetry relative to an imaginary
axis running from the phenyl rings point of attachment to the remainder
of the xanthene dye through a point para to the point of attachment. The
phenyl xanthene dyes may be activated. Furthermore, the phenyl xanthene
dyes may be conjugated to one or more substances including other dyes.
The phenyl xanthene dyes are useful for a number of purposes, including
labels for use in automated DNA sequencing as well the formation of
fluorescent "bar codes" for polymeric particles used in the multiplexed
analysis of analytes.