Self-assembly of semifluorinated minidendrons attached to electron-acceptor groups into pyramidal columns

The synthesis and self-assembly of twelve semifluorinated first-generation dendrons or minidendrons attached to electron-acceptor (n-type) groups generated from various combinations of eight acceptors and three dendrons are reported. Dendrons attached to small electron-acceptor molecules mediate their self-assembly into pi-stacks located in the center of a supramolecular helical pyramidal column with the long axis of the acceptor perpendicular to the long axis of the column. Dendrons attached to large electron-acceptor molecules, such as perylene bisimide, mediate the assembly of their acceptors in an unprecedented arrangement of pi-stacks that have the long axis of the acceptors parallel to the long axis of the supramolecular pyramidal column. All supra-molecular columns self-organize into various periodic columnar arrays that exhibit liquid-crystalline phases, crystalline phases, or a liquid-crystalline phase with enhanced intracolumnar order. The present study demonstrates the simplicity and the versatility of the concept of assembly of n-type electroactive groups mediated by semifluorinated dendrons and assesses the scope and limitations of this supramolecular strategy.