For the concept of aromaticity, energetic quantification is crucial. However, this has been elusive for excited-state (Baird) aromaticity. Here we report our serendipitous discovery of two nonplanar thiophene-fused chiral [4n]annulenes Th4 COT Saddle and Th6 CDH Screw, which by computational analysis turned out to be a pair of molecules suitable for energetic quantification of Baird aromaticity. Their enantiomers were separable chromatographically but racemized thermally, enabling investigation of the ring inversion kinetics. In contrast to Th6 CDH Screw, which inverts through a nonplanar transition state, the inversion of Th4 COT Saddle, progressing through a planar transition state, was remarkably accelerated upon photoexcitation. As predicted by Baird’s theory, the planar conformation of Th4 COT Saddle is stabilized in the photoexcited state, thereby enabling lower activation enthalpy than that in the ground state. The lowering of the activation enthalpy, i.e., the energetic impact of excited-state aromaticity, was quantified experimentally to be as high as 21–22 kcal mol–1.

In stacking-based supramolecular polymerization, chiral hydrogen bonding (H-bonding) monomers often prefer to adapt a homochiral monomer sequence. Herein, we investigated the polymerization of a chiral thiophene-fused cyclooctatetraene (COT) as a novel nonplanar-core monomer and found the first example of the formation of an alternating heterochiral supramolecular copolymer. Although single enantiomer (−) or (+)-COT alone did not polymerize, when (−) and (+)-COT were mixed together, supramolecular polymerization took place to give a stereochemically alternating copolymer. By means of the microcrystal electron crystallography of a shorter side-chained COT analogue, we found that the resulting heterochiral supramolecular copolymer adapted an alternating arrangement of H-bonded and polar π-stacked parts. A computational study using density-functional theory (DFT) suggested that such an alternating heterochiral preference occurs because it allows two thiophene amide moieties facing each other to effectively cancel their in-plane dipole moments.

31 surfaces were investigated in the present work. The dynamic growth behavior was observed with low energy electron microscopy (LEEM), and the local surface structure change was monitored with selected area low energy electron diffraction (LEED). Xray generated photo emission electron microscopy using synchrotron radiation (SR-XPEEM) was employed in order to see the variation of the chemical state on the surface. On both p 3 × p 3 and p 31 × p 31 surfaces, Sb adsorption induces the surface structural change and modifies the chemical interaction of In atoms with Si. In atoms are replaced by impinged Sb atoms, and the discharged In atoms form islands.

Using a photochemically fluttering thiophene-fused cyclooctatetraene derivative (COT) as a nonplanar chiral monomer, we have succeeded in remotely suspending the supramolecular polymerization in a temporal manner by a completely new strategy. The COT monomer with an 8π electron core adopts a saddle shape in the ground state and flutters 5.8 × 10 3 times faster upon photoirradiation than in the dark as a result of the stabilized planar conformation by the excited-state aromaticity (Baird aromaticity). Detailed investigation revealed that without photoirradiation the rate constant of the fluttering motion is 1/560 times smaller than that of the chain elongation, indicating that the fluttering of COT does not affect the chain elongation in the dark. In contrast, under photoirradiation (365 nm), the fluttering of COT is at least 11 times more rapid than the chain elongation, thereby suppressing the elongation event. The rapid fluttering of COT to suspend the chain elongation is not accompanied by a decrease in active monomer concentration, leading to depolymerization.

We have developed the advanced ink containing ball spacers for the precise positioning of spacers using Ink‐Jet method. This technology has been achieved by selecting ink properties in order that ball spacers gather in BM area in droplet drying process.