The dendronized perylene 3,4:9,10-tetracarboxylic acid bisimide (PBI) (3,4,5)12G1-3-PBI was recently shown to self-assemble in a complex helical column containing tetramers of PBI as the basic repeat unit. The tetramers contain a pair of two molecules arranged side-by-side and another pair in the next stratum of the column, turned upside-down and rotated around the column axis. The intra- and inter-tetramer rotation angle and stacking distance are different. At high temperature this dendronized PBI self-assemble via a thermodynamically controlled process in a 2D hexagonal columnar phase while at low temperature in a 3D orthorhombic columnar array via a kinetically controlled process. Here we report the synthesis and structural analysis of a library of (3,4,5)nG1-3-PBI with n = 14 to 4, and the discovery that at n = 9 and 8 the kinetically controlled self-assembly from low temperature is transformed in a thermodynamically controlled process. In addition, the orthorhombic columnar array for n = 9 and 8 transforms from the thermodynamic product into kinetic one. The new thermodynamic product at low temperature is a self-repaired helical column with identical intra- and inter-tetramer distance of 3.5 Å that forms a 3D monoclinic periodic array via a kinetically controlled self-assembly process. This remarkable discovery is important for both the fundamental understanding of the self-assembly and for technological applications related to the molecular design of supramolecular electronics and solar cell.
Citation: Journal of the American Chemical Society
Pub Type: Journals
self assembly, diffraction, organic electronics, photovoltaics