Article
Polymer Science
Steffen M. Weidner, Andreas Meyer, Jana Falkenhagen, Hans R. Kricheldorf
Summary: This study investigated the polycondensation of ethyl l-lactate (ELA) using seven different tin catalysts and other compounds. The results showed successful synthesis of polylactide (PLA) and revealed the formation of polycondensation and cyclic structures through loops on the surface of crystallites in the solid state.
Article
Chemistry, Multidisciplinary
Rami Hador, Michael Shuster, Vincenzo Venditto, Moshe Kol
Summary: This study proposes a new approach to tolerate stereoerrors in the polymer by crowding them in a stereogradient copolymer. A zirconium complex of an amine tris(phenolate) ligand is used as a catalyst for the ring opening polymerization of meso-lactide at room temperature, and stereogradient copolymers are formed in the polymerization of mixtures of meso-lactide/L-lactide at 180 degrees C. These stereogradient copolymers exhibit enhanced crystallinities compared to stereorandom copolymers obtained with tin octanoate.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Polymer Science
Lidong Feng, Xinchao Bian, Gao Li, Xuesi Chen
Summary: The study shows that the compatibility between PLLA and PLDLA-m decreases as the L-lactate unit content in PLDLA-m decreases, impacting the crystallization and compatibility of the blends.
Article
Polymer Science
Steffen M. Weidner, Andreas Meyer, Hans R. Kricheldorf
Summary: L-lactide was polymerized in toluene using tin(II) 2-ethylhexanoate as the catalyst. The crystalline properties of the resulting polyLAs were studied under different concentrations, reaction times, and temperatures. It was found that the presence of solvent promoted cyclization, leading to the formation of cyclic polylactides. A new hypothesis for the crystal growth of cyclic polyLAs was proposed.
Article
Chemistry, Multidisciplinary
Thomas M. McGuire, Antoine Buchard, Charlotte Williams
Summary: A commercial Sn(II) catalyst combined with a commercial alcohol has been found to efficiently convert waste PLLA plastic into pure L-lactic acid at low temperatures. This catalyst system exhibits not only excellent catalytic activity and yield, but also significantly lower usage compared to previous catalysts.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Hans R. Kricheldorf, Steffen M. Weidner, Andreas Meyer
Summary: The alcohol-initiated ROPs of l-lactide at 160 degrees C for 72 hours produced high melting crystallites with melting temperatures of 189-193 degrees C, especially when using cyclic Sn(ii) compounds as catalysts. This suggests that the choice of catalyst can significantly impact the properties of the crystalline products.
Article
Chemistry, Multidisciplinary
Thomas M. McGuire, Antoine Buchard, Charlotte Williams
Summary: This study presents an efficient method for chemical recycling of waste Poly(L-lactic acid) (PLLA) using a commercial Sn(II) catalyst and nonvolatile commercial alcohol. The depolymerization of PLLA to yield pure L-lactide (L-LA) can be achieved at low temperatures, and the catalyst system shows outstanding activity and selectivity. Furthermore, the catalyst system can be recycled multiple times without loss of its catalytic productivity.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Linnea Cederholm, Jakob Wohlert, Peter Olsen, Minna Hakkarainen, Karin Odelius
Summary: By selecting solvents that strongly interact with the monomer, the peak temperature of poly(L-lactic acid) can be reduced, enabling efficient chemical recycling and repolymerization of the recycled L-lactide with control over molecular weight and dispersity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Megha D. Deokar, Baijayantimala Garnaik, Swaminathan Sivaram
Summary: Well-defined six-arm star-branched bio-degradable block copolymers were prepared using controlled ring-opening polymerization and a sequential monomer addition method. The study found that the sequence of enchainment could be changed by reversing the order of monomer addition, resulting in different crystalline or amorphous blocks. However, disruption of the block structure was observed in one of the copolymers due to competing transesterification reactions. Differential scanning calorimetry studies showed interesting phase morphologies in these sequence-controlled block copolymers. Blending these copolymers with a commercially sourced polymer led to improved tensile toughness in the blend.
Article
Polymer Science
Julia Sanchez-Bodon, Leire Ruiz-Rubio, Estibaliz Hernaez-Lavina, Jose Luis Vilas-Vilela, Ma Isabel Moreno-Benitez
Summary: This study focuses on the effectiveness of using CuAAC click reaction to link a fluorophore to PLLA surface. It also discusses the covalent immobilization of the anti-inflammatory drug indomethacin on PLLA surface using the same reaction method.
Article
Polymer Science
Steffen M. Weidner, Andreas Meyer, Hans R. Kricheldorf
Summary: Alcohol-initiated ROPs of L-Lactide at high temperature result in the formation of cyclic and linear PLA. The crystalline structure of cyclic PLA is made up by extended rings, which is different from that of linear PLA. Experimental results further support this interpretation.
Article
Chemistry, Multidisciplinary
Xianyue Zhou, Qiuyang Liu, Guangqiang Xu, Rulin Yang, Hongguang Sun, Qinggang Wang
Summary: Chemical upcycling of end-of-life poly(lactide) plastics to lactide, lactate ester and new poly(lactide) has been achieved using magnesium bis[bis(trimethylsilyl)amide] [Mg(HMDS)2] as a promoter. Mg(HMDS)2 demonstrated high efficiency in L-lactide polymerization and poly(lactide) depolymerization. A new depolymerization-repolymerization strategy was proposed to directly transform poly(lactide) into new poly(lactide), providing a theoretical basis for catalyst design and promoting the development of degradable polymers.
CHINESE CHEMICAL LETTERS
(2023)
Article
Polymer Science
Lidong Feng, Xinchao Bian, Gao Li, Xuesi Chen
Summary: By investigating the thermal properties, morphology, and thermal stability of PLLA/PDLA blends, a new stereoamorphous mesophase (sam-PLA) structure was discovered, and the relationship between different phases in the PLLA/PDLA blends was explored.
Article
Biochemistry & Molecular Biology
Renata Barczynska-Felusiak, Malgorzata Pastusiak, Piotr Rychter, Bozena Kaczmarczyk, Michal Sobota, Andrzej Wanic, Anna Kaps, Marzena Jaworska-Kik, Arkadiusz Orchel, Piotr Dobrzynski
Summary: The study presented a synthesis method for poly(l-lactide) with bacteriostatic properties using specific zinc complexes as initiators, showing stronger antibacterial and antifungal activities compared to primary Schiff bases. The synthesized polymer exhibited significant antibacterial effects against Pseudomonas aeruginosa, Staphylococcus aureus, and Aspergillus brasiliensis, without fibroblast cytotoxicity.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2021)
Article
Polymer Science
Shuang Li, Han Lu, Ling Zhu, Meixue Yan, Xiaohui Kang, Yi Luo
Summary: The mechanisms of ring-opening polymerization of L-lactide and trimethylene carbonate using DMAP/Sac as a bifunctional catalyst were investigated using DFT calculations. A new two-component organocatalyst Adenine/Sac was also designed and evaluated for its catalytic performance. The results showed that Adenine/Sac exhibited higher catalytic activity in the ring-opening of L-lactide and trimethylene carbonate.
Article
Chemistry, Multidisciplinary
Yu Harabuchi, Hiroki Hayashi, Hideaki Takano, Tsuyoshi Mita, Satoshi Maeda
Summary: Systematic reaction path exploration revealed the entire mechanism of Knowles's light-promoted catalytic intramolecular hydroamination. This study found that bond formation/cleavage competes with single electron transfer and that reduction and proton shuttle processes proceed concertedly.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Review
Chemistry, Physical
Satoshi Maeda, Yu Harabuchi, Hiroki Hayashi, Tsuyoshi Mita
Summary: Predicting the entire process of a chemical reaction and directly discovering chemical reactions and their product yields through kinetic simulations is made possible by narrowing the search space based on the kinetic analysis of the reaction path network. The authors propose a practical method by combining artificial force induced reaction and rate constant matrix contraction methods, offering forward and backward algorithms for this purpose. The effectiveness of these methods is demonstrated through numerical verification and application to actual reaction discovery, highlighting the challenges and prospects of ab initio reaction discovery.
ANNUAL REVIEW OF PHYSICAL CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Geoffrey Roberts, Jonathan Haslam, Satoshi Maeda
Summary: In this study, a workflow employing the AFIR method was used to investigate the self-assembly process of the SIFSIX-3-Zn MOF. Multiple competing pathways involving interconvertible intermediates were identified, providing a plausible explanation for the stochastic multistage processes believed to be key in MOF formation. This work represents the first application of an automated reaction mechanism discovery method to a MOF system.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Atsuyuki Nakao, Yu Harabuchi, Satoshi Maeda, Koji Tsuda
Summary: This research proposes a method based on graph neural networks to optimize the choice of transformation patterns for efficient energy landscape exploration. Artificial force has proven to be useful in overcoming energy barriers and searching a large portion of the energy landscape.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Polymer Science
Kai Chen, Chun -Yu Chen, Hsin-Lung Chen, Ryoya Komaki, Nao Kawakami, Takuya Isono, Toshifumi Satoh, Du -Yuan Hung, Ying-Ling Liu
Summary: This study reveals the strong effects of molecular architecture and configuration on the self-assembly behavior of sugar-based block copolymers. The configuration prescribed by the substituted positions of the block chains exerts a significant influence on the formation of hydrogen bonding and the resistance against bending. These findings provide insights into the controlled fabrication of ordered structures in green materials.
Article
Polymer Science
Xiaochao Xia, Tianle Gao, Feng Li, Ryota Suzuki, Takuya Isono, Toshifumi Satoh
Summary: Switchable polymerization has potential for synthesizing sequence-controlled macromolecules similar to natural biopolymers, but is limited to three-and four-component systems. We expanded its scope to five-component systems using a reactivity gradient among 12 monomers. Different copolymerizations were achieved using a catalyst, allowing for the synthesis of gradient and block copolymers. Anhydride reactivity was predicted using 13C NMR chemical shifts. This comonomer library allows for the prediction and preparation of more complex copolymer structures.
Article
Polymer Science
Huan Li, Yingying Li, Yudan Wang, Lijia Liu, Hongxing Dong, Chunhong Zhang, Toshifumi Satoh
Summary: In this study, a Lys-BPEA crosslinker was synthesized using primary amines rich in lysine end groups. An antibacterial self-healing hydrogel (PAA/Lys-BPEA) was prepared by introducing polyamine Lys-BPEA into PAA via ionic bonding and electrostatic interaction. The PAA/Lys-BPEA hydrogel exhibited excellent antibacterial and self-healing properties, making it an ideal choice for the design of smart self-healing devices and antibacterial surface coatings.
Article
Polymer Science
Ryohei Sato, Atsuo Utagawa, Koji Fushimi, Feng Li, Takuya Isono, Kenji Tajima, Toshifumi Satoh, Shin-ichiro Sato, Hiroshi Hirata, Yoshihiro Kikkawa, Takuya Yamamoto
Summary: The redox behaviors of macrocyclic molecules with an entirely pi-conjugated system were investigated in this study. Cyclic P3HT with different degrees of polymerization (DPn) were synthesized, and its unique redox behaviors were compared with linear P3HT. Cyclic P3HT showed a decrease in HOMO level and greater stability during cyclic voltammetry measurement, indicating stronger dicationic properties due to polaron-polaron interactions.
Article
Chemistry, Multidisciplinary
Yong Zheng, Julong Jiang, Mingoo Jin, Daiyo Miura, Fei Xue Lu, Koji Kubota, Tasuku Nakajima, Satoshi Maeda, Hajime Ito, Jian Ping Gong
Summary: In this study, a novel strategy for real-time visualization of mechanochemical damages in hydrogels was developed using prefluorescent probes via oxygen-relayed free-radical trapping. This method allows for the detection of mechanochemical damages in hydrogels made from brittle networks of varied chemical structures, without introducing any chemical structural changes in the materials.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Biochemistry & Molecular Biology
Ruben Staub, Philippe Gantzer, Yu Harabuchi, Satoshi Maeda, Alexandre Varnek
Summary: In this article, the feasibility of using Neural Network Potentials (NNP) to accelerate the Artificial Force Induced Reaction (AFIR) method is investigated. A novel theoretical study of ethylene hydrogenation using the AFIR method is reported, and the resulting reaction path network is analyzed. The limitations of general purpose NNP models in such studies are identified, and a solution involving fast semiempirical predictions is proposed to overcome these challenges.
Article
Chemistry, Multidisciplinary
Erika Terada, Takuya Isono, Toshifumi Satoh, Takuya Yamamoto, Toyoji Kakuchi, Shinichiro Sato
Summary: Recently, temperature-responsive polymers tethered to oligooxyethylene side chains terminated with alkyl groups were experimentally investigated. Molecular dynamics simulations were used to study aqueous solutions of poly(glycidyl ether)s with different numbers of oxyethylene units. The thermal responses of chain extensions, hydrogen bond recombination, and water-solvation shells were analyzed. The phase-transition temperature was not directly related to the polymer-chain extensions, but the temperature response of the water-solvation shell around the alkyl group showed a noticeable correlation. The relationship between TCRP and TCLP was found to be affected by polymer-chain fluctuation.
Article
Chemistry, Physical
Taisuke Hasegawa, Satoshi Hagiwara, Minoru Otani, Satoshi Maeda
Summary: This article presents a combined simulation method that combines single-component artificial force induced reaction (SC-AFIR) and effective screening medium combined with the reference interaction site model (ESM-RISM), enabling the exploration of reliable reaction pathways at the solid-liquid interface. It was applied to study the dissociation pathway of an H2O molecule at the Cu(111)/water interface.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Hien Thi Phan, Shoko Furukawa, Koto Imai, Hiroya Tomita, Takuya Isono, Toshifumi Satoh, Ken'ichiro Matsumoto
Summary: Bacterial polyhydroxyalkanoate (PHA) synthase PhaC(AR) and its mutated variants were used to synthesize block copolymers with poly(d-lactate) (PDLA) segments. Beneficial mutations N149D and F314H increased the incorporation of D-lactate (LA) units, resulting in the synthesis of P(3HB)-b-PDLA and P(3HHx)-b-PDLA. This study demonstrates a new method for the synthesis of block copolyesters with isotactic PDLA segments from renewable resources using engineered polyester synthase.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Article
Polymer Science
Yamato Ebii, Yoshinobu Mato, Feng Li, Kenji Tajima, Takuya Yamamoto, Takuya Isono, Toshifumi Satoh
Summary: In this study, multicyclic polystyrene (mc-PS) was successfully synthesized through the cyclopolymerization of alpha,omega-dinorbornenyl end-functionalized PS macromonomers mediated by the Grubbs third-generation catalyst. The number of cyclic units in the obtained mc-PS was controlled by adjusting the macromonomer-to-G3 ratio, with a maximum of 239 units achieved. The developed cyclopolymerization strategy provides a new approach for the synthesis of multicyclic polymers and has significant implications for fundamental studies and material applications.
Article
Chemistry, Multidisciplinary
Yaodong Wang, Yudan Wang, Lijia Liu, Kexiao Sang, Chunhong Zhang, Toshifumi Satoh
Summary: Metal-free catalysts have emerged as an important research focus in catalysis due to the growing concern over heavy metal pollution. In this study, a heterogeneous catalyst, l-Pro-l-Pro-l-Phe-l-Phe-OMe, was synthesized by connecting an aromatic amino acid dipeptide (l-Phe-l-Phe-OMe) with a proline dipeptide (l-Pro-l-Pro) through solid phase synthesis. The catalyst's structure was characterized using SEM, XRD, NMR, and FTIR spectroscopy, with X-ray diffractometry revealing a rod crystal structure. Furthermore, l-Pro-l-Pro-l-Phe-l-Phe-OMe exhibited superior catalytic activity compared to a homogeneous small molecule catalyst (high enantioselectivity, ee > 97%) in heterogeneous asymmetric aldol reactions and demonstrated good recyclability.
REACTION CHEMISTRY & ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Michal Novotny, Matus Dubecky, Frantisek Karlicky
Summary: This paper investigates the accuracy of different DFT-based computational approaches in calculating the equilibrium lattice constants and exfoliation energy of hexagonal boron nitride (h-BN). The results are compared with experiments and reference QMC calculations to evaluate the accuracy of these computational methods.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2024)
Article
Chemistry, Multidisciplinary
Luigi Crisci, Federico Coppola, Alessio Petrone, Nadia Rega
Summary: The charge transfer dynamics in asymmetrically substituted indenotetracene molecules upon photo-excitation were investigated using real-time time-dependent density functional theory simulations. The study found that the electron-donating character of the substituents affects the overall electronic energy spacing and ultrafast charge transfer dynamics.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2024)
Article
Chemistry, Multidisciplinary
Vasilii Korotenko, Hendrik Zipse
Summary: The stability of various radicals and molecules has been studied using different theoretical methods, and good correlations between theoretical calculations and experimental results have been found. The effects of hydrogen bonding interactions on the stability of oxygen-centered radicals have also been investigated.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2024)
Article
Chemistry, Multidisciplinary
Oleg Egorov, Michael Rey, Dominika Viglaska, Andrei V. Nikitin
Summary: In this work, the rovibrational energy levels of four isotopologues of methylene were calculated using a new accurate ab initio potential energy surface. The accuracy of the calculations was improved by considering scalar relativistic effects, DBOC, and high-order electronic correlations. For the first time, all available experimental rovibrational transitions were reproduced with high accuracy, without any empirical corrections.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2024)
