Design, synthesis and pH sensing properties of novel PAMAM light-harvesting dendrons based on rhodamine 6G and 1,8-naphthalimide.

Herein we report on the design, divergent synthesis and photophysical behavior of novel PAMAM light-harvesting dendrons from first and second generation. The surface of novel compounds is labeled with 4-alkylamino-1,8-naphthalimide yellow-green emitting "donor" fluorophores capable of absorbing light and efficiently transferring the energy to a single rhodamine "acceptor" dye. Due to the pH dependent rhodamine absorption the novel systems show "off-on" switching energy transfer mechanism from alkaline to acid media. The results obtained illustrate the high potential of the synthesized wavelength-shifting fluorophores as efficient pH chemosensing materials.