title: Two-dimensional nanostructures by the assembly of n-type tetraazaanthracene-based conjugated molecules.
abstract: On the basis of our previous communication concerning a new family of thiophene-armed tetraazaanthracene molecules, we present a further intensive investigation on this class of compounds substituted with different alkyl chains and their self-assembled two-dimensional (2D) nanostructures. These tetraazaanthracene molecules with different alkyl chains were prepared in good yields using the synthetic strategy we developed. In addition to the expected typical n-type character, one compound exhibited aggregation behavior upon electrochemical reduction. Moreover, all molecules in the neutral state showed a strong tendency to aggregate in a binary solvent, as confirmed by optical spectral measurements. To investigate such self-assembly behavior, a phase-transfer method with a dichloromethane/methanol (2:3) binary solvent system was used to prepare the nanostructures. By means of atomic force microscopy, transmission electron microscopy, and X-ray diffraction, we found that the morphology of assembled 2D sheet-like structures could be adjusted by varying the alkyl chain. The weak interactions arising from the heteroatoms (N and S) in the conjugated backbones play a key role in the formation and stabilization of layered structures.
authors.affiliation: School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (P.R. China).
authors.forename: Chunyang
authors.initials: C
authors.lastname: He
authors.forename: Dongqing
authors.initials: D
authors.lastname: Wu
authors.forename: Fan
authors.initials: F
authors.lastname: Zhang
authors.forename: Minzhao
authors.initials: M
authors.lastname: Xue
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Zhuang
authors.forename: Feng
authors.initials: F
authors.lastname: Qiu
authors.forename: Xinliang
authors.initials: X
authors.lastname: Feng
keywords: nanostructures; noncovalent interactions; self-assembly; tetraazaanthracene; two-dimensional structures