Shape-persistent fluorescent tetraphenylmethane dendrimers†
We report the first examples of a new class of rigid dendrimers made of three-dimensional tetraphenylmethane units connected by ethynylene linkers. Designed to obtain a persistent globular shape, minimal backfolding of terminal groups and well-defined cavities at low generations, the dendrimers were synthesized until the second generation by a convergent strategy based on Sonogashira couplings. Their structure and size were confirmed by NMR, MALDI-TOF-MS and SEC among other techniques. The dendrimers showed intrinsic fluorescence with quantum yields of ∼0.6.