Molecular Engineering of N-heteroacenes and Macrocyclic Arenes: Design, Synthesis and Properties.

摘要

Detailed in this thesis is molecular engineering of N-heteroacenes and macrocyclic arenes including design, synthesis and investigations on their organic semiconductor properties. Chapter 1 reviews the advances in the area of the large N-heteroacenes, which have four or more linearly fused six-membered rings, in terms of structure, synthesis, molecular packing and their applications as electronic materials.;Chapter 2 presents three new members of N-heteropentacenes that have adjacent pyrazine and dihydropyrazine rings at one end of the pentacene backbone. Interesting findings from this study include self-complementary N-H•••N H-bonds in the solid state, solvent-dependent UV-vis absorptions caused by H-bonding and new p-type organic semiconductors with field effect mobility up to 0.7 cm2V-1s-1.;Chapter 3 introduces novel silylethynylated N-heteropentacenes that have three adjacent pyrazine rings at the center of a pentacene backbone. These hexaazapentacenes exhibit a record low energy level of lowest unoccupied molecular orbital (LUMO) for N-heteropentacenes and thus able to oxidize dihydroanthracene to anthracene. Their synthetic precursors are the corresponding dihydrohexaaza pentacenes, which also exhibit interesting H-bonding.;Chapter 4 presents a novel electron-deficient thiadiazolophenazine, which was found to function as an air-stable n-type organic semiconductor in solution-processed thin film transistors with field effect mobility up to 0.7 cm2V -1s-1. We demonstrate that S-N dipole-dipole interactions enforce self-complementary head-to-head packing while bulky triisopropylsilyl groups in this compound lead to a one dimensional pi-pi stacking of the aromatic cores.;Chapter 5 reports novel conjugated macrocycles based on phenanthrene, which are connected with varied linkers leading to planar and tubular structures. We have conducted a comparative study on flat or nearly flat conjugated macrocycles with focus on self-assembly behavior and solution-processed organic semiconductor property which is dependent on their ability of self-aggregation in solution. Lewis acid-catalyzed [4+2] benzannulation on the flat macrocycle 5.2 leads to the coronal macrocycle, whose pi-backbone is a new segment of [6,6]-carbon nanotube. This suggests a new strategy to synthesize pi-extended nanorings from flat conjugated macrocycles that are more easily accessed.