Synthesis of seminaphtho-phospha-fluorescein dyes based on the consecutive arylation of aryldichlorophosphines.

Seminaphtho-phospha-fluorescein (SNAPF), a phosphine-oxide-containing unsymmetric fluorescein dye, was synthesized based on the consecutive arylation of PhPCl2, followed by Friedel-Crafts cyclization. The resulting SNAPF exhibited several attractive photophysical properties including an intense fluorescence in the NIR region and a large Stokes shift.