Self-Assembly of Functionalized Twistarenes into Supramolecular Assemblies with Chiroptical Property and Photoconductive Behavior.

A pair of novel chiral 1-phenylethylamine-modified twistarenes (4 and 11; compound 4 = 9,14-di-tert-butyl-7,16-diphenyl-2-(1-phenylethyl)-1H-benzo[8',9']triphenyleno[2',3':6,7]fluoreno[2,1,9-def]isoquinoline-1,3(2H)-dione) have been synthesized and characterized, and how the solvent component affects the chirality transfer of their self-assembled processes is investigated in mixtures with THF and H2O. The ordered assembly of 11 exhibits circular dichroism response. In addition, both 11a and 11b display positive photoconducting behavior.

Straightforward Synthesis of Pentagon-Embedded Expanded [11]Helicenes for Radiative Cooling Property.

Two new pentagon-embedded carbo[11]helicenes have been designed and synthesized in a three-step process, which are the first example of carbo[11]helicenes through the post-functionalization of twistacene. TD-DFT analyses indicate that both of them possess high enantiomerization barriers of 42.29 kcal/mol and 40.76 kcal/mol, respectively. They emit strong red fluorescence and can be chemically oxidized into stable cationic radicals upon addition of AgSbF6 evidenced by the bathochromic-shifted absorption spectra and the appearance of electronic paramagnetic resonance (EPR) signals. In addition, such helical derivatives can be chosen as radiative cooling materials in a glass model house, and the maxima of 5.4 °C for the former and 6.5 °C for the latter are found in the comparative tests, which might be caused by the NIR reflective response.

Heptagon-Embedded Helicene Derivatives: Synthesis, Crystal Structural Analyses, and Circularly Polarized Luminescence.

Two pairs of isomers of heptagon-embedded helical arenes (3/6 and 10/13) have been strategically prepared, where the molecular structures of 3 and 13 have been identified through single crystal X-ray diffraction analysis. The effect of the heptagon unit on the physical properties of 3, 6, 10, and 13 is investigated in a comparative manner, and the results indicate that the optical enantiomers of 13 obtained from HPLC exhibit promising chiroptical properties.

Synthesis, Crystal Analysis, and Physical Properties of Double [6]helicene-Containing Heteroarenes with Circularly Polarized Luminescence.

Two novel helical heteronanographenes bearing a [6]helicene unit (3a and 5a) have been synthesized, and their molecular structures are unambiguously determined via single-crystal X-ray diffraction analyses. Density functional theory calculations suggest that the as-prepared compounds have isomerization barriers of 29.02 kcal/mol for 3a and 34.07 kcal/mol for 5a, respectively. Optical enantiomers of 5a exhibit appealing chiroptical properties.

Effect of Annulation Mode of Twistarene on the Physical Property and Self-Assembly Behavior of Functionalized Curved Aromatic Molecules.

Four novel curved polycyclic aromatic hydrocarbons 3 a, 5, 8, 15 a have been synthesized and characterized, where molecules 3 a and 15 a bear [5]carbohelicene units. X-ray single crystal analyses indicate that compound 3 a shows offset packing arrangements of (P5 )- and (M5 )-isomers, and 15 a has a symmetrical plane and looks like a butterfly. In comparison, 8 exhibits a slightly curved structure, in which the significant convex-to-convex π-overlap with the shortest distance of 3.42 Šoccurs. In addition, the effect of annulation mode of twistarenes on the physical properties, self-assembly behaviors, and switchable photoconductivity of the as-prepared curved aromatic compounds were further examined in a comparative manner.