On-Surface Crystallization Behaviors of H-Bond Donor–Acceptor Complexes at Liquid/Solid Interfaces

Abstract

Two-dimensional (2D) crystallization behaviors of A-TPC n (n = 4, 6, 10), T3C 4 , and hydrogen-bonded complexes T3C 4 @TPC n (n = 4, 6, 10) are investigated by means of scanning tunneling microscope (STM) observations and density functional theory (DFT) calculations. The STM observations reveal that A-TPC 4 , A-TPC 10 , and T3C 4 self-organize into dumbbell-shaped structures, well-ordered bright arrays, and zigzag structures, respectively. Interestingly, T3C 4 @TPC 10 fails to form the cage-ball structure, whereas T3C 4 @TPC 4 and T3C 4 @TPC 6 co-assemble into cage-ball structures with the same lattice parameters. The filling rates of the balls of these two kinds of cage-ball structures depend heavily on the deposition sequence. As a result, the filling rates of the cages in T3C 4 /A-TPC n (n = 4, 6) with deposition of T3C 4 anterior to A-TPC n are higher than those in A-TPC n /T3C 4 (n = 4, 6) with the opposite deposition sequence. Furthermore, lattice defects formed by T3C 4 coexist with the cage-ball structures. Moreover, the similar energy per unit area of lattice defects (−0.101 kcal mol −1 Å −2 ) and the two cage-ball networks (−0.194 and −0.208 kcal mol −1 Å −2 , respectively), illustrating the similar stabilities of lattice defects and cage-ball networks, demonstrates the rationality of lattice defects. Combining STM investigations and DFT calculations, this work could provide a useful approach to investigate the 2D crystallization mechanisms of supramolecular liquid crystals on surfaces.

π-Conjugated Macrocycle Host–Guest Coassembly with C60 on HOPG

“…Host–guest coassembly is a highly efficient strategy to design accurate and controllable orderly π-conjugated architectures on solid surfaces at the molecular level system, which makes host–guest chemistry attract much attention. − Host networks with rigid cavities will not be changed by guest molecules. , The host–guest architectures with the dynamic process are also observed by scanning tunneling microscopy (STM), which has developed a new way for the observation of the world at the nanometer scale. − Recently, many coassembled systems on the solid/liquid interface have been investigated by the STM technique. − Zhang et al reported that two shape-persistent circular molecules displayed a surprising concentration-controlled self-assembly behavior at the highly oriented pyrolytic graphite (HOPG)/liquid interface and captured C70 into the cavities to make up stable complexes . Cheng et al studied the adsorption of selectivity and competitivity with guest molecules C70 and coronene in the electron donor–acceptor-conjugated macrocycles systems.…”