Main content area

Temperature-Directed Hierarchical Surface Supramolecular Assembly

Wang, Li-Mei, Yue, Jie-Yu, Zheng, Qi-Yu, Wang, Dong
Journal of physical chemistry 2019 v.123 no.22 pp. 13775-13781
ambient temperature, annealing, chemical interactions, entropy, graphene, nanomaterials
The hierarchical organization of building blocks is an important characteristic of self-assembly. Herein, we report a series of triangular hierarchical assemblies formed by C₃-symmetric 5,10,15-triethyl-10,15-dihydro-5H-diindolo[3,2-a:3′,2′-c]carbazole-2,7,12-tricarbaldehyde (M1) on the graphite surface. The molecule assembles into a hexagonal array on the graphite surface at room temperature with a trimeric assembly motif as the basic building block of the hierarchical assembly. With the increase of annealing temperature, the sizes of triangles in hierarchical assemblies vary from large to small with the presence of antiparallelly arranged molecular dimers as building blocks at the triangular boundaries. The hierarchical-order-level-dependent intermolecular interaction and molecule–substrate interaction were modeled, and the entropy contributions of alkyl substitution at different temperatures were proposed to account for the observed structural evolution process. This work provides a new example of hierarchical assembly directed by temperature and is beneficial for the understanding of both the assembling process and the underlying kinetics and thermodynamics for hierarchical molecular nanostructures.