Nucleoside-Assisted Self-Assembly of Oligo(p-phenylenevinylene)s at Liquid/Solid Interface: Chirality and Nanostructures

Abstract

The formation of DNA nucleoside-assisted π-conjugated nanostructures was studied by means of scanning tunneling microscopy (STM) and force field simulations. Upon adsorption of the achiral oligo(p-phenylenevinylene) (OPV) derivative at the liquid/solid interface, racemic conglomerates with mirror related rosettes are formed. Addition of the DNA nucleosides D- and L-thymidine, which act as "chiral handles", has a major effect on the supramolecular structure and the expression of chirality of the achiral OPV molecules. The influence of these "chiral handles" on the expression of chirality is probed at two levels: monolayer symmetry and monolayer orientation with respect to the substrate. This was further explored by tuning the molar ratio of the building blocks. Molecular modeling simulations give an atomistic insight into the monolayer construction, as well as the energetics governing the assembly. Thymidine is able to direct the chirality and the pattern of OPV molecules on the surface, creating chiral lamellae of π-conjugated dimers.

Supramolecular Chirality in Self-Assembled Systems

“…For example, when Lhistidine methyl ester (L-His-OMe) or D-histidine methyl ester (D-His-OMe) was mixed with g-TPP/Zn cyclohexane gels, very different CD and fluorescence spectra were obtained ( Figure 125B and 125C). 356 Smith and co-workers thoroughly investigated two-component organogels based on the coassembly of an L-lysine dendron (151) with different amines ( Figure 126A). For these systems, when the chiral amines were used for the coassembly, very interesting chiral recognition phenomena can be detected.…”

Hydrogen bond directed assembly of oligothiophene/fullerene superstructures on Au(111)

“…To a first-order approximation the assemblies are mirror images. Chiral rosette formation as a consequence of H-bonding and surface adsorption has been studied before with both chiral [30,32,39,40] and achiral [33,34] monomers.…”

“…Self-complementary H-bonding has been shown to compete with strong adsorbate-substrate and substratesubstrate interactions to program the formation of closed cyclic assemblies, or rosettes [27,[29][30][31][32][33][34][35][36][37][38][39][40], that can be visualized with atomic resolution on surfaces [41][42][43]. Among the motifs, phthalhydrazide (PH) derivatives have been found to form H-bonded cyclic trimers (e.g., (PH) 3 , Fig.…”

Concentration-dependent structure and structural transition from chirality to nonchirality at the liquid–solid interface by coassembly

“…STM experiments about the solution concentration-dependence were carried out at 20-25°C in the atmospheric environment. STM tips were prepared by mechanically cutting Pt/Ir wire (80 : 20). Except for flattening to remove the tilting effect of the substrate plane, the images were recorded under constant current mode and shown without further processing.…”