Lyotropic Liquid Crystallinity of Linear and Star Poly(quinoxaline-2,3-diyl)s: Isotropic-Liquid Crystal Phase Equilibria in Tetrahydrofuran

Hasegawa H., Terao K., Sato T., et al. Lyotropic Liquid Crystallinity of Linear and Star Poly(quinoxaline-2,3-diyl)s: Isotropic-Liquid Crystal Phase Equilibria in Tetrahydrofuran. Macromolecules, 52(9), 3158-3164, April 16, 2019. Copyright © 2019, American Chemical Society. https://doi.org/10.1021/acs.macromol.9b00460

Pre-regulation of the planar chirality of pillar[5]arenes for preparing discrete chiral nanotubes

Regulating the chirality of macrocyclic host molecules and supramolecular assemblies is crucial because chirality often plays a role in governing the properties of these systems. Herein, we describe pillar[5]arene-based chiral nanotube formation via pre-regulation of the building blocks' chirality, which is different from frequently used post-regulation strategies. The planar chirality of rim-differentiated pillar[5]arenes is initially regulated by chiral awakening and further induction/inversion through stepwise achiral external stimuli. The pre-regulated chiral information is well stored in discrete nanotubes by interacting with a per-alkylamino-substituted pillar[5]arene. Such pre-regulation is more efficient than post-regulating the chirality of nanotubes

Real-time chirality transfer monitoring from statistically random to discrete homochiral nanotubes

Real time monitoring of chirality transfer processes is necessary to better understand their kinetic properties. Herein, we monitor an ideal chirality transfer process from a statistically random distribution to a diastereomerically pure assembly in real time. The chirality transfer is based on discrete trimeric tubular assemblies of planar chiral pillar[5]arenes, achieving the construction of diastereomerically pure trimers of pillar[5]arenes through synergistic effect of ion pairing between a racemic rim-differentiated pillar[5]arene pentaacid bearing five benzoic acids on one rim and five alkyl chains on the other, and an optically resolved pillar[5]arene decaamine bearing ten amines. When the decaamine is mixed with the pentaacid, the decaamine is sandwiched by two pentaacids through ten ion pairs, initially producing a statistically random mixture of a homochiral trimer and two heterochiral trimers. The heterochiral trimers gradually dissociate and reassemble into the homochiral trimers after unit flipping of the pentaacid, leading to chirality transfer from the decaamine and producing diastereomerically pure trimers

Photochemistry and spectroscopy of molecules at surfaces: Insights from ab initio molecular dynamics

Resumen del trabajo presentado al 2nd CECAM Workshop: "Challenges in reaction dynamics of gas-­surface interactions and methodological advances in dissipative and non­adiabatic processes", celebrado en Toulouse (France) del 27 al 30 de septiembre de 2021.Peer reviewe

Synthesis and luminescent properties of pyrenylvinylene-substituted tripylborane

A novel luminescent compound, bis((E)-2-pyren-1-yl-vinyl)-2, 4, 6-triisopropylphenylborane (3) was synthesized by hydroboration reaction and was fully characterized. The obtained compound was further investigated by single-crystal X-ray diffraction analysis and DFT calculations. The extended structure tells us their herringbone structures with closely faced pairs of the molecules. Comparing the photoluminescent spectra between solution-state and solid state, the spectrum of the solid state of the compound 3 exhibited dramatically red-shifted fluorescent emission. This change also supports the efficient π-stacking behavior of the compound 3

シンキ ケイコウセイ ホウソ ガンユウ コウブンシ ノ ゴウセイ

京都大学0048新制・課程博士博士(工学)甲第13845号工博第2949号新制||工||1435(附属図書館)UT51-2008-C761京都大学大学院工学研究科高分子化学専攻(主査)教授 中條 善樹, 教授 赤木 和夫, 教授 杉野目 道紀学位規則第4条第1項該当Doctor of EngineeringKyoto UniversityDA

Synthesis and luminescent properties of pyrenylvinylene-substituted tripylborane

A novel luminescent compound, bis((E)-2-pyren-1-yl-vinyl)-2, 4, 6-triisopropylphenylborane (3) was synthesized by hydroboration reaction and was fully characterized. The obtained compound was further investigated by single-crystal X-ray diffraction analysis and DFT calculations. The extended structure tells us their herringbone structures with closely faced pairs of the molecules. Comparing the photoluminescent spectra between solution-state and solid state, the spectrum of the solid state of the compound 3 exhibited dramatically red-shifted fluorescent emission. This change also supports the efficient π-stacking behavior of the compound 3

Catalytic asymmetric synthesis using chirality-switchable helical polymer as a chiral ligand

ingle-handed PQXphos, i.e., helical poly(quinoxaline-2, 3-diyl)s bearing diarylphosphino pendant groups, served as remarkable chiral ligands in palladium-catalyzed asymmetric hydrosilylation of styrenes and asymmetric biaryl synthesis by Suzuki–Miyaura coupling, affording up to 98 % enantiomeric excess (e.e.) in both reactions. A palladium complex of high-molecular-weight variant (1000mer) of PQXphos could be reused eight times by virtue of the formation of an insoluble polymer complex. PQXphos underwent solvent-dependent inversion of the helical sense, enabling production of either of two enantiomeric products using a single PQXphos