Importance of Molecular Meshing for the Stabilization of Solvophobic Assemblies

Abstract

The effect of the methyl groups in neutral gear-shaped amphiphiles (GSAs) on the stability of nanocubes was investigated using a novel C-symmetric GSA, which was synthesized using selective alternate trilithiation of a pentabrominated hexaphenylbenzene derivative. The lack of only one methyl group in the GSA decreased the association constant for the assembly of the nanocube by 3 orders of magnitude. A surface analysis recently developed by the authors (SAVPR: surface analysis with varying probe radii) was carried out for characteristic isomers of the nanocube consisting of C-symmetric GSAs. It was found that the methyl groups near the equator of the nanocube play a significant role in the stabilization of the nanocubes.

Induced-fit expansion and contraction of a self-assembled nanocube finely responding to neutral and anionic guests

“…3b ), suggesting a large distortion around the poles by the encapsulation of a rodlike or a large planar molecule with the longest side of 12 Å. This is consistent with the previous finding that the molecular meshing around the equator is stronger than that around the poles 40 , 41 . In every case, a further desymmetrization of the nanocube upon the complexation was not observed by 1 H NMR spectroscopy, indicating that the tumbling motion of the guest molecule(s) in the nanocube is much faster than the NMR timescale.…”

Polarizability and isotope effects on dispersion interactions in water

“…1c), suggesting that the dispersion interactions around X play a significant role on the stability of the nanocube. As the twelve substituents (X) along the equator (X E ) are denser than the six substituents around the poles (X P ), the dispersion interactions (X···X and X···π) around X E is likely to be stronger 23 .…”

Multiple‐Porphyrin Functionalized Hexabenzocoronenes

“…Hexaphenylbenzenes (HPBs) and their oxidized derivatives hexa‐ peri ‐hexabenzocoronenes (HBCs) have received tremendous attention during the past 20 years in materials chemistry, for example in molecular electronics and nonlinear optics . They have proven to be a suitable scaffold for catalytic applications, the design of supramolecular architectures, as well as a perfectly sized template for the preparation of nano‐ring and nano‐ball structures. In contrast, porphyrins and related macrocycles, which are found in nature in different appearances such as heme, chlorophyll, or bacteriochlorophyll, have attracted the attention from the scientific community ever since their discovery.…”

“…Hexaphenylbenzenes (HPBs) and their oxidized derivatives hexa-peri-hexabenzocoronenes (HBCs)h ave received tremendous attention during the past 20 years in materials chemistry, for example in moleculare lectronics and nonlinearo ptics. [1][2][3][4][5] They have provent obeasuitable scaffold for catalytic applications, [6,7] the design of supramolecular architectures, [8,9] as well as ap erfectly sized template fort he preparation of nanoring [10,11] and nano-ball [12] structures.I nc ontrast, porphyrins and related macrocycles,w hich are foundi nn ature in different appearances such as heme, chlorophyll,o rb acteriochlorophyll, have attracted the attention from the scientific community ever since their discovery.D ue to their photophysical charac-teristics, featuring high extinction coefficients in the visiblelight region, porphyrins have provent ob ea ni deal chromophoref or light-harvesting architectures. [13][14][15][16][17][18][19][20][21] Thec ombination of both buildingb locks, porphyrins and HPBs, was initiated in 2002 by the synthesis of aH PB core, surrounded by six directly meso-attached porphyrins.…”