Review
Chemistry, Analytical
Shuyi Yuan, Lei Zhao, Fangqin Wang, Lilan Tan, Datong Wu
Summary: Chiral resolution is important and challenging due to the different biological activity and physicochemical property of (R)- and (S)-isomers. Optically active helical polymers have been synthesized as chiral selectors, which are used for chromatographic chiral separation and enantioselective adsorption/crystallization, with good enantioseparation efficiency.
JOURNAL OF SEPARATION SCIENCE
(2023)
Review
Polymer Science
Guanzhao Wu
Summary: Chiral separation by HPLC using a CSP is a reliable method for obtaining pure enantiomers. Helical polyacetylene derivatives show excellent chiral recognition abilities and are promising CSP candidates for HPLC. This review discusses the development of helical polyacetylene derivatives with different chiral pendants and their potential as coated CSPs for enantioseparation in HPLC.
Review
Chemistry, Medicinal
David Jin Han Seog, Nguyen van Kien, Jae Jeong Ryoo
Summary: This updated minireview focuses on chiral stationary phases (CSPs) based on amino alcohols. The study highlights the use of amino alcohols as starting materials for the preparation of chiral catalysts in asymmetric organic synthesis and CSPs for chiral separations. Important developments and applications of various CSPs, including Pirkle-type CSPs, ligand exchange CSPs, alpha-amino acid-derived amino alcohol CSPs, and symmetric CSPs, are summarized to propose ideas for developing new CSPs with improved performance.
Article
Chemistry, Multidisciplinary
Chen Yuan, Wenyan Jia, Ziyun Yu, Yanan Li, Min Zi, Li-Ming Yuan, Yong Cui
Summary: This study demonstrates that two olefin-linked covalent organic frameworks (COFs) featuring chiral crown ether groups can be general chiral stationary phases (CSPs) for extensive separation in gas chromatography (GC) and both normal-phase and reversed-phase high-performance liquid chromatography (HPLC). These COFs show high stability under different chemical environments and have the ability for enantioselective recognition of guest molecules.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Kentaro Tanaka, Ryo Inoue, Yasuhiro Morisaki
Summary: By utilizing enantiopure building blocks, optically active cyclic dimers, trimers, and tetramers were prepared, showing clear Cotton effects and corresponding CPL signs. While the cyclic dimer did not emit CPL, the cyclic trimer and tetramer exhibited intense CPL emissions with a relatively high dissymmetry factor. Their optical and chiroptical properties were reproduced by time-dependent density functional theory calculations.
CHEMISTRY-AN ASIAN JOURNAL
(2022)
Article
Chemistry, Medicinal
William L. Champion, William L. Watts, Weston J. Umstead
Summary: While not initially a focus or priority, the activity of individual enantiomers of widely used pesticides has been emphasized in recent decades. This study investigated the enantioselective separations of seven such organophosphorus pesticides using chiral high-performance liquid chromatography. The results provide new chiral separations and insight into the effect of mobile phase strength and temperature on the separations, allowing for further optimization of analysis conditions.
Article
Chemistry, Analytical
Attila Bajtai, Istvan Ilisz, Robert Berkecz, Ferenc Fulop, Wolfgang Lindner, Antal Peter
Summary: This study investigated the diastereo- and enantioseparation of Cinchona alkaloid analogs using liquid chromatographic and subcritical fluid chromatographic modalities. The Chiralpak IC and IG columns were found to be the best in both modalities. Temperature was identified as a crucial factor in the separation process.
JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
(2021)
Article
Chemistry, Analytical
Adriaan Ampe, Elena Bandini, Ken Broeckhoven, Frederic Lynen
Summary: Temperature-responsive liquid chromatography (TRLC) offers an alternative approach for optimization of retention and selectivity in HPLC. By utilizing temperature gradients on stimuli-responsive stationary phases and eliminating the need for solvent gradients, TRLC can be used with aqueous mobile phases, making it a green alternative to reversed-phase separations. This study developed a flow-through modification procedure that allows on-column modification of aminopropyl silica columns, achieving identical column efficiency compared to existing TRLC columns. Flow-through produced columns showed higher retention at elevated temperatures despite reduced carbon load. The presence of stationary phase gradients was observed, and its influence on retention was studied through novel retention experiments.
ANALYTICA CHIMICA ACTA
(2023)
Article
Biochemical Research Methods
Yi-Lun Yan, Dong Guo, Jia-Lin Wu, Xi-Hao Tang, Jia-Jun Luo, Shu-Qing Li, Jun Fan, Sheng-Run Zheng, Wei-Guang Zhang, Song-Liang Cai
Summary: This study demonstrates the utilization of stable spherical covalent organic frameworks (SCOFs) as matrixes for the fabrication of new chiral stationary phases (CSPs). The synthesized SCOF-based CSPs exhibit high resolution abilities for enantiomeric separation in high-performance liquid chromatography (HPLC). Compared to silica-based CSPs, the prepared SCOF-based CSPs show superior acid and base stability.
JOURNAL OF CHROMATOGRAPHY A
(2022)
Article
Chemistry, Multidisciplinary
Aoi Morisaki, Ryo Inoue, Yasuhiro Morisaki
Summary: This study reports the synthesis of optically active cyclic tetramers from two enantiomerically pure [2.2]paracyclophane compounds. The combination of the absolute configurations of the planar chiral pseudo-ortho- and pseudo-meta-[2.2]paracyclophane units determined the formation of parallel-#- or weave-#-structures. The weave-#-shaped cyclic tetramer exhibited good chiroptical properties and emitted circularly polarized luminescence with high anisotropy and brightness.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Review
Polymer Science
Hai Zhong, Jianping Deng
Summary: Chirality is widely present in nature and plays a significant role in living organisms. Polyamides, as an important class of polymers, can create attractive chiral polymers when chirality is introduced. Optically active polyamides have diverse applications in fields such as asymmetric catalysis and membrane separation.
MACROMOLECULAR RAPID COMMUNICATIONS
(2021)
Review
Chemistry, Analytical
Bei Liu, Hui Li, Kaijun Quan, Jia Chen, Hongdeng Qiu
Summary: This review article focuses on the application of periodic mesoporous organosilica (PMO) materials with organic functionalities in chromatographic separation, including packed columns and monolithic columns. The correlation between PMO chromatographic stationary phase compositions and chromatographic performance is discussed by summarizing the functional bridges, synthesis methods, and modification methods. The research directions for further development of a more highly efficient PMO chromatographic column are also outlined.
TRAC-TRENDS IN ANALYTICAL CHEMISTRY
(2023)
Article
Chemistry, Medicinal
Daisuke Hirose, Mai Nozaki, Miyuki Maruta, Katsuhiro Maeda
Summary: This article reports solvent-dependent helix inversion in poly(diphenylacetylene) (PDPA) derivatives. The helix-senses of the polymer backbone were stably maintained at room temperature, and the optically active substituents in the pendants generated opposite circularly polarized light in the same solvent. The combination of the polymer backbone's helix-sense and the chirality of the pendants led to different chiral recognition abilities.
Article
Biochemical Research Methods
Denisa Folprechtova, Kveta Kalikova, Kian Kadkhodaei, Cornelia Reiterer, Daniel W. Armstrong, Eva Tesarova, Martin G. Schmid
Summary: Novel psychoactive substances (NPS) are synthetic compounds designed to mimic the effects of recreational drugs while avoiding current drug control laws. Chiral NPS present challenges due to limited information on the pharmacological and toxicological properties of their enantiomers. The use of vancomycin-based chiral stationary phases shows high enantioselective potential in fast separation methods for various classes of NPS in both supercritical fluid chromatography and liquid chromatography.
JOURNAL OF CHROMATOGRAPHY A
(2021)
Review
Biochemical Research Methods
Huifeng Liu, Zhihai Wu, Jia Chen, Jianhua Wang, Hongdeng Qiu
Summary: Chirality is a common phenomenon in nature and the separation of chiral drugs is crucial for their safe utilization. High-performance liquid chromatography (HPLC) is an effective tool for compound separation and analysis, with chromatographic packing playing a key role. Chiral pharmaceutical separation and analysis in HPLC rely on chiral stationary phases (CSPs), thus various CSPs are being developed to meet the needs of chiral drug separation and analysis.
JOURNAL OF CHROMATOGRAPHY A
(2023)
Article
Chemistry, Medicinal
Tomoyuki Ikai, Shogo Okuda, Eiji Yashima
Summary: Two novel poly(biphenylylacetylene)s containing asymmetric alkylphenyl groups were synthesized, and their effects on macromolecular helicity induction and static helicity memory were investigated. The polymers exhibited high chiral recognition ability in high-performance liquid chromatography experiments.
Article
Polymer Science
Tomoyuki Ikai, Shoki Takeda, Eiji Yashima
Summary: In this study, a dynamically racemic helical copolymer was discovered to fold into an excess one-handed helix in the presence of a small amount of optically active amines, and the induced helicity was retained after removal of the chiral amines. The copolymer showed high sensitivity for detecting the chirality of chiral amines, even in the presence of a very low amount, and exhibited Cotton effects.
Article
Chemistry, Multidisciplinary
Makoto Tadokoro, Masaki Itoh, Ryota Nishimura, Kensuke Sekiguchi, Norihisa Hoshino, Hajime Kamebuchi, Jun Miyazaki, Fumiya Kobayashi, Motohiro Mizuno, Tomoyuki Akutagawa
Summary: A new H-bonded crystal with three imidazole and three imidazolate groups was synthesized to achieve a higher-temperature proton conductor. The crystal exhibited a rare cubic network topology and showed a proton conductivity higher than that of other materials. The high proton conductivity was attributed to molecular rotations and hopping motions as well as isotropic whole-molecule rotation at elevated temperatures.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Physical
Takuya Kurihara, Munehiro Inukai, Motohiro Mizuno
Summary: In this study, the dynamics of CO2 adsorption and diffusion in metal-organic frameworks (MOFs) were investigated using solid-state nuclear magnetic resonance (NMR) spectroscopy. The rotational motion of ligands in the narrow pore windows of MOFs was found to affect the dynamics of adsorbed CO2. The diffusion rate of adsorbed CO2 was significantly slower in the MOFs with smaller pores, and it was influenced by the steric hindrance of the rotating ligands. Additionally, the diffusion of adsorbed CH4 was also affected by the steric hindrance, showing a size-selective effect.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Polymer Science
Tomoyuki Ikai, Shogo Okuda, Motoki Aizawa, Eiji Yashima
Summary: The one-handed helix induction and chiral recognition abilities of cis-poly(biphenylylacetylene) derivatives with chiral and achiral pendant groups were investigated. The chiral recognition abilities were significantly influenced by the types of pendant residues.
Article
Chemistry, Inorganic & Nuclear
Takuya Kurihara, Kotaro Ohara, Kentaro Kadota, Hitoshi Izu, Yusuke Nishiyama, Motohiro Mizuno, Satoshi Horike
Summary: Glassy-state coordination polymers (CPs) composed of anionic and neutral ligands were constructed. The relationship between the ligand dynamics and glass formability of CPs was studied.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Wei Zheng, Kosuke Oki, Ranajit Saha, Yuh Hijikata, Eiji Yashima, Tomoyuki Ikai
Summary: Defect-free one-handed contracted helical tubular ladder polymers with a pi-electron-rich cylindrical helical cavity were synthesized and exhibited high enantioseparation abilities. The formation of the pi-electron-rich cylindrical helical cavity is key to the highly-enantioseparation ability. Molecular dynamics simulations suggested that chiral aromatics can be encapsulated by specific pi-pi and/or hydrophobic interactions.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Polymer Science
Tomoyuki Ikai, Shun Anzai, Kosuke Oki, Eiji Yashima
Summary: In this study, a series of novel chiral/achiral copolymers with configurationally labile optically active helicene pendants were synthesized. It was found that the copolymers could maintain their preferred helicity even after the pendant helicene units were completely racemized, thanks to the static memory of the main-chain helicity. On the other hand, the helicity memory of the helicene-free homopolymer was lost rapidly.
JOURNAL OF POLYMER SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Tomoyuki Ikai, Koshi Nakamura, Kosuke Mizumoto, Kosuke Oki, Eiji Yashima
Summary: In this study, we report a novel way to remotely control the helicity of chiral/achiral biphenylylacetylene copolymers with amphiphilic oligo(ethylene glycol) (OEG) side chains. By introducing a small amount of chiral binaphthyl residues (<= 10 mol %) at the terminal of achiral OEG spacers, a complete one-handed helix can be induced in water. The helix-sense can be inverted at a specific spacer length. The superiority of this covalent-bond driven remote helicity control over noncovalent helicity induction is demonstrated.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Tomoyuki Ikai, Kosuke Oki, Shoya Yamakawa, Eiji Yashima
Summary: Enantiopure [6]helicene and carbo[7]helicene with opposite helicity were synthesized simultaneously and quantitatively (>99 %) through stepwise acid-promoted intramolecular alkyne annulations. The stereocontrol of helical handedness of the [6]- and [7]helicenes was achieved by the doubly axial chirality of the precursors. The cyclizations proceeded in a stepwise manner, resulting in the production of enantiopure circularly polarized luminescent [6]- and [7]helicenes with opposite helicity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Tomoyuki Ikai, Masaki Ito, Kosuke Oki, Nozomu Suzuki, Eiji Yashima
Summary: A series of poly(biarylylacetylene)s (PBAs) with axially-chiral pyridyl-N-oxide residues and different substituents were synthesized. Despite having the same twist-sense, all PBAs formed a preferred-handed helix with the helical sense preference depending on the substituents. Among them, the propoxy-bound helical PBA showed exceptional chiral recognition ability as a CSP in HPLC, efficiently resolving various chiral aromatic and aliphatic alcohols, which are difficult to separate using commercially-available CSPs. These practical CSPs can be produced from racemic PBA through deracemization of the biaryl units using a chiral alcohol.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Tomoyuki Ikai, Sayaka Miyoshi, Kosuke Oki, Ranajit Saha, Yuh Hijikata, Eiji Yashima
Summary: We report the synthesis and resolution of a fully p-conjugated helical ladder polymer with a rigid helical cavity, composed of achiral units. The isolated excess one-handed helical ladder polymer showed strong circular dichroism and thermal stability, maintaining its optical activity in solution.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Misaki Nakagawa, Shinpei Kusaka, Atsushi Kiyose, Toshinobu Nakajo, Hiroaki Iguchi, Motohiro Mizuno, Ryotaro Matsuda
Summary: In this study, the authors found that by confining trans-4-styrylpyridine (4-spy) in a flexible metal-organic framework (MOF) nanospace, [2+2] cycloadducts can be selectively obtained, even when the distance between two C C bonds of 4-spy in the crystal is larger than the conventionally observed upper limit. This unusual cyclization reaction is suggested to occur due to the transient proximity of the 4-spy due to the swing motion in the nanospace. The MOF nanospace with its high degree of molecular structural freedom can be applied to different platforms that do not require the fine constraints of reactive distances for solid-phase reactions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Tomoyuki Ikai, Yuki Morita, Tsuyoshi Majima, Shoki Takeda, Ryoma Ishidate, Kosuke Oki, Nozomu Suzuki, Hajime Ohtani, Hiromi Aoi, Katsuhiro Maeda, Kento Okoshi, Eiji Yashima
Summary: It is found that an extremely small amount of chiral BPA monomers can completely control the one-handed helicity in synthetic polymers, and chiral substituents can amplify the helical bias. The helical structures of the one-handed helical copolymers can be determined by high-resolution atomic force microscopy and X-ray diffraction. The strong helix-biasing power of the chiral BPA makes it useful for enantiomer separation in chromatography.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Kosuke Oki, Wei Zheng, Eiji Yashima, Tomoyuki Ikai
Summary: Optically-pure triptycene-based metallomacrocycles were synthesized for the first time through the coordination-driven self-assembly of enantiopure triptycene-derived ligands. Additionally, a pair of enantiomeric homochiral metallomacrocycles were also produced through the coordination-driven homochiral self-sorting of racemic ligands, demonstrating the shape-persistent nature of the ladder-structured ligands.
CHEMICAL COMMUNICATIONS
(2023)
