摘要:
AbstractBiodriven self‐organization of α‐quinquethiophene (t5): Cast films of 5′TA3′‐t5 are electroactive, photoluminescent, and chiral. Their growth is not directed by intermolecular Watson–Crick hydrogen bonding between the A⋅⋅⋅T moieties of interacting molecules, but is governed by intra‐ and intermolecular thiophene–nucleobase stacking interactions.magnified imageThe synthesis and properties of 5′TA3′‐t5 (8 a) and 5′CG3′‐t5 (8 b) conjugates, in which the self‐complementary dinucleotides TA and CG are covalently bound to the central ring of α‐quinquethiophene (t5), are described. According to molecular mechanics calculations, the preferred conformation of both 8 a and 8 b is that with the dinucleotide folded over the planar t5 backbone, with the nucleobases facing t5 at stacking distance. The calculations show that the aggregation process of 8 a and 8 b is driven by a mix of nucleobase‐thiophene interactions, hydrogen bonding between nucleobases (non Watson–Crick (W&C) in TA, and W&C in CG), van der Waals, and electrostatic interactions. While 8 b is scarcely soluble in any solvents, 8 a is soluble in water, indicating that the aggregates of the former are more stable than those of the latter. Microfluidic‐induced self‐assembly studies of 8 a showed the formation of lamellar, spherulitic, and dendritic supramolecular structures, depending on the concentration and solvent evaporation time. The self‐assembled structures displayed micrometer dimensions in the xy plane of the substrate and nanometer dimensions in the z direction. Spatially resolved confocal microscopy and spectroscopy showed that the aggregates were characterized by intense fluorescence emission. Cast films of 8 a from water solutions showed chirality transfer from the dinucleotide to t5. The hole mobility of the cast films of 8 a was estimated using a two‐electrode device under high vacuum and found to be up to two orders of magnitude greater than those previously measured for dinucleotide–quarterthiophene conjugates under the same experimental conditions.