Facile pathways to multichromophoric arrays based on a truxene platform

Multi-branched dyes were synthesized using a truxene platform appropriately functionalized with iodo residues, the key step here being a controlled iodination process giving access to mono-, di-, tri- and hexa-derivatives. Conversion of the iodo compounds to the corresponding alkynes followed by cross-coupling with iodophenylindacenes catalysed by Pd(0) or with chloro-Pt(II) complexes catalysed by Cu(I) enabled the introduction of multiple chromophore/luminophore units. Both neutral and cationic species involving Pt(II) centres were obtained in excellent yields. Connection of ethynylpyrene units to boron within the hexa-grafted truxene Bodipys provided very efficient cascade singlet energy transfer from the pyrene to the yellow emitter. Irradiation in the truxene core also resulted in quantitative energy transfer to the organic dyes.