Article
Electrochemistry
Juan Pablo F. Rebolledo-Chavez, Marisela Cruz-Ramirez, David Ramirez-Palma, Janet Ocampo-Hernandez, Angel Mendoza, Fernando Cortes-Guzman, Luis Ortiz-Frade
Summary: This paper reports the synthesis, characterization, and electrochemical studies of a series of novel Ni-II complexes, as well as the comparison with a tris-chelate complex to understand the role of flexible tetradentate ligands in CO2 reduction. Spectro-electrochemical experiments and theoretical studies were conducted to rationalize the electrochemical reductions and predict the pathway of CO2 reduction.
ELECTROCHIMICA ACTA
(2021)
Article
Polymer Science
Michael R. Martinez, Ferdinando De Luca Bossa, Mateusz Olszewski, Krzysztof Matyjaszewski
Summary: In this study, a poly(n-butyl methacrylate) macroinitiator was depolymerized, and high concentrations of monomer were successfully recovered. This method achieved selective monomer recovery through rotary distillation, while also discovering the possibility of alkyl halide decomposition leading to reduced initiation efficiency and increased thermal stability of the polymer.
Article
Polymer Science
Michael R. Martinez, Ferdinando De Luca Bossa, Mateusz Olszewski, Krzysztof Matyjaszewski
Summary: This study demonstrates a new method for efficient depolymerization of a poly(n-butyl methacrylate) macroinitiator at high temperature, achieving high monomer recovery rates and selectivity. Incubation of the macroinitiators led to evidence of alkyl halide decomposition, affecting the initiation efficiencies and thermal stability of the polymer.
Article
Chemistry, Inorganic & Nuclear
Gege Qiu, Donglin Diao, Leo Chaussy, Sabine Michaud-Chevallier, A. Jalila Simaan, Paola Nava, Alexandre Martinez, Cedric Colomban
Summary: In this study, a capped bioinspired ligand with a tris(2-pyridyl-methyl)amine (TPA) unit and a triazole-based intramolecular H-bonding secondary sphere was synthesized. The resulting cage has a well-defined cavity and combines hydrophobic nature with H-bonding properties.
DALTON TRANSACTIONS
(2022)
Article
Polymer Science
Arman Moini Jazani, Dirk J. Schild, Julian Sobieski, Xiaolei Hu, Krzysztof Matyjaszewski
Summary: This study demonstrates the ATRP of OEOMA(500) in water using CuBr2 and TPMA as catalysts under blue or green-light irradiation without the need for additional reagents or deoxygenation. The choice of TPMA supplier and purity significantly affect the reaction outcome.
MACROMOLECULAR RAPID COMMUNICATIONS
(2022)
Article
Chemistry, Inorganic & Nuclear
Nadia Alessandra Carmo dos Santos, Elena Badetti, Federico Begato, Klaus Wurst, Giulia Licini, Cristiano Zonta
Summary: The continuous improvement of reaction screening methodologies has led to the development of novel high-throughput analytical technologies. Chiroptical spectroscopies have emerged as promising techniques, especially when combined with stereodynamic probes for optical signal amplification. Mixing metals in the synthesis of novel supramolecular architectures based on TPMA can influence the chiroptical properties of the formed compounds.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Gege Qiu, Djamel Eddine Khatmi, Alexandre Martinez, Paola Nava
Summary: The study reveals that diastereomers with P/P (or M/M) configurations of the CTV and TPA units are more stable than those with P/M (or M/P) configurations. Isomerization pathways with low energy barriers account for the observed H-1-NMR signal.
Review
Chemistry, Inorganic & Nuclear
Carlo Bravin, Elena Badetti, Giulia Licini, Cristiano Zonta
Summary: TPMA is an important ligand that can form stable and catalytically active complexes with various metals, leading to its wide applications in different fields such as sensors, molecular switches, chiral probes, and building blocks in the synthesis of supramolecular cages.
COORDINATION CHEMISTRY REVIEWS
(2021)
Article
Chemistry, Inorganic & Nuclear
Josiah G. D. Elsberg, Stephen N. Anderson, David L. Tierney, Eric W. Reinheimer, Lisa M. Berreau
Summary: The synthetic, structural, and reactivity investigations of tris-(2-pyridylmethyl)amine (TPA)-ligated Cu(II) 1,3-diketonate complexes show anaerobic retro-Claisen type C-C bond cleavage reactivity exceeding that found in analogs supported by chelate ligands with fewer and/or weaker pyridyl interactions.
DALTON TRANSACTIONS
(2021)
Article
Chemistry, Physical
Marcos Palmeira-Mello, Juliana Lima Souza, Anthuan Ferino Perez, Amanda dos Santos Cavalcanti, Suzana Assad Kahn, Nady Passe-Coutrin, Idania Rodeiro Guerra, Antonio Domenech-Carbo, Ulises Javier Jauregui-Haza, Alessandra Mendonca Teles de Souza, Mauricio Lanznaster, Gerardo Cebrian-Torrejon
Summary: Osteosarcoma is a rare malignant bone tumor with high levels of microRNAs and key proteins involved in intracellular signaling pathways. Chemotherapy with Cisplatin and Doxorubicin can cause side effects and drug resistance. The tri(2-pyridylmethyl)amine shows potential activity against osteosarcoma cells by interacting with DNA and other biological targets.
JOURNAL OF MOLECULAR STRUCTURE
(2021)
Article
Chemistry, Physical
Alyona A. Starikova, Maxim G. Chegerev, Andrey G. Starikov
Summary: A computational study on cobalt complexes with specific ligands was conducted to predict magnetic bistability mechanisms and understand the relationship between exchange interactions and the nature of radical groups. By comparing the results with analogous compounds, directional synthesis of new paramagnetic species was planned.
CHEMICAL PHYSICS LETTERS
(2021)
Article
Polymer Science
Bengang Zhang, Xinyi Chen, Antonio Pizzi, Mathieu Petrissans, Stephane Dumarcay, Anelie Petrissans, Xiaojian Zhou, Guanben Du, Baptiste Colin, Xuedong Xi
Summary: Condensed tannin copolymerized with hyperbranched tris(2-aminoethyl)amine-urea to form a particleboard thermosetting adhesive without aldehydes, meeting the relevant standards for internal bond strength. The adhesive can cure effectively at a low temperature of 180 degrees C and has zero formaldehyde emission. The tannin acts as a cross-linking agent, enhancing the overall bonding performance. The chemical analysis reveals that substitution and rare reaction occur between tannin and the amine and amide groups.
Article
Chemistry, Physical
Koteswara Rao Gorantla, Bhabani S. Mallik
Summary: In this study, the reaction mechanism of the oxygen evolution reaction catalyzed by penta-coordinated and hexa-coordinated cobalt complexes was investigated using density functional theory. It was found that the activation barrier for the oxygen-oxygen bond formation by the penta-coordinated complex was lower than that of the hexa-coordinated complex. Through spin density analysis, it was observed that the oxo-complexes were stabilized by sharing spin density on the nitrogen atoms. Additionally, the penta-coordinated complex required a lower activation free energy barrier in the catalytic cycle compared to the hexa-coordinated complex.
SUSTAINABLE ENERGY & FUELS
(2021)
Article
Chemistry, Inorganic & Nuclear
Tomoyo Misawa-Suzuki, Ryoto Ikeda, Ryoya Komatsu, Ryo Toriba, Ryo Miyamoto, Hirotaka Nagao
Summary: Bis(2-pyridylmethyl)ether (bpme) was used as a tridentate ligand coordinated to the cobalt(II) or iron(III) center, leading to the development of new material conversion reaction centers. The study revealed the formation of five-coordinate cobalt(II) complexes and hexa-coordinate iron(III) complexes. In addition, distinctive redox behaviors were observed in organic solvents.
Article
Engineering, Chemical
Zhe Zhai, Kuo Chen, Hao Yang, Yan Huang, Hongling Lan, Xingming Jie, Q. Jason Niu, Yuchao Zhao
Summary: In this study, a patching strategy was employed to fabricate a polyarylate-polyamide hybrid nanofiltration membrane with improved ionic rejection and high permeance. The membrane exhibited excellent anti-compression ability and long-term stability. The study also calculated the permeability of the membrane, which was among the most permeable nanofiltration membranes reported recently.
Article
Chemistry, Multidisciplinary
Tomoya Ishizuka, Takahiko Kojima
Summary: This manuscript surveys the synthesis and properties of porphyrin derivatives with fused five-membered rings at the periphery. These derivatives exhibit unique properties, such as expanded aromatic and anti-aromatic circuits passing through the outer rim of the fused rings.
JOURNAL OF PORPHYRINS AND PHTHALOCYANINES
(2023)
Article
Chemistry, Multidisciplinary
Takayuki Iwata, Masato Hanada, Satoru Kumagai, Tatsuro Yoshinaga, Yoshihito Shiota, Kazunari Yoshizawa, Mitsuru Shindo
Summary: In this study, Hiyama coupling was achieved through intramolecular substituent transfer from silicon, resulting in the formation of 1,8,13-trisubstituted chiral triptycenes based on triptycene. The proximity effect of substituents on triptycene played a crucial role in the formation of the oxy-palladacycle and the activation of the silyl group for sigma-bond metathesis. After bromination and nucleophilic ring opening, a secondary intramolecular Hiyama coupling provided diverse 1,8,13-trisubstituted chiral triptycenes. Optical resolution of 1,8,13-triptycene yielded optically active forms for the first time.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Inorganic & Nuclear
Keita Shichijo, Yohei Kametani, Yoshihito Shiota, Kazunari Yoshizawa, Mamoru Fujitsuka, Hisashi Shimakoshi
Summary: A dehydrocorrin complex, Co(II)-pyrocobester (P ( -Co(II) )), was semisynthesized from cyanocobalamin and its photochemical and electrochemical properties were compared to those of the cobester (C ( -Co(II) )). The UV-vis absorptions of P ( -Co(II) ) in CH2Cl2 were red-shifted due to the pi-expansion of the macrocycle in the pyrocobester. The redox couple of P ( -Co(II) ) was positively shifted compared to that of C ( -Co(II) ), coinciding with the high electronegativity of the dehydrocorrin macrocycle. The reactivity of P ( -Co(I) ) was evaluated by its reaction with methyl iodide.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Seiji Ogo, Takeshi Yatabe, Tamon Tome, Riko Takenaka, Yoshihito Shiota, Kenji Kato
Summary: In this study, a homogeneous catalyst is used to synthesize hydrogen peroxide using H2 and O2 in water, eliminating the need for flammable H2/O2 mixtures and cocatalysts. The catalyst is capable of extracting electrons from H2, storing them for the reduction of O2, and then converting the reduced oxygen to H2O2. The catalyst exhibits the highest turnover number (TON) among all homogeneous catalysts.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Multidisciplinary Sciences
Hiroto Fujisaki, Tomoya Ishizuka, Hiroaki Kotani, Yoshihito Shiota, Kazunari Yoshizawa, Takahiko Kojima
Summary: Efficient oxidation of alkanes, especially methane, is essential for using natural gas as chemical feedstock. Current industrial processes use high-temperature and high-pressure steam reforming to generate a gas mixture that can be further converted into products like methanol. However, this study demonstrates a new strategy using N-heterocyclic carbene-ligated Fe-II complexes to capture hydrophobic methane substrate from an aqueous solution, oxidize it to hydrophilic methanol, and release it back into the solution. By increasing the size of the hydrophobic cavities, the effect can be enhanced, achieving a turnover number of 5.0 x 10(2) and a methanol selectivity of 83% during a 3-hour methane oxidation reaction.
Article
Chemistry, Inorganic & Nuclear
Yohei Kametani, Kei Ikeda, Kazunari Yoshizawa, Yoshihito Shiota
Summary: In this study, the reduction mechanism of nitrite by a copper(II) complex was investigated using density functional theory calculations. Two possible reaction pathways were proposed based on different coordination modes of nitrite to copper, and the Cu-ONO pathway was found to be energetically favorable. The involvement of different proton-coupled electron transfer modes in each pathway was revealed by intrinsic reaction coordinate and intrinsic bond orbital analyses.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Tomoya Ishizuka, Atsushi Hosokawa, Takuya Kawanishi, Hiroaki Kotani, Yipeng Zhi, Takahiko Kojima
Summary: The promise of artificial photosynthesis in solving environmental and energy issues has sparked intensive research into photocatalytic systems for CO2 reduction. This study focuses on a dinuclear Ru-II complex that acts as a self-photosensitizing catalyst, demonstrating high efficiency and durability in CO2 reduction to produce CO.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Tomoya Ishizuka, Taichi Kogawa, Chisato Ogawa, Hiroaki Kotani, Yoshihito Shiota, Kazunari Yoshizawa, Takahiko Kojima
Summary: We synthesized and characterized a Ru-II-OH2 complex and studied its coordination equilibrium and oxidation reaction. The complex exhibits η6 coordination and intramolecular hydrogen bonding, which are important for catalytic oxidation reactions.
Review
Chemistry, Physical
Hiroto Fujisaki, Takahiko Kojima
Summary: This article surveys recent progress in the efficient and selective functionalization of methane using molecular metal complexes as catalysts. The reactions involve C-H bond cleavage by high-valent metal-oxo complexes and C-H bond activation at lower-valent metal centers, resulting in the formation of C-O or C-C bonds through oxygen-rebound, reductive elimination or insertion processes. The importance of hydrophobic environments around metal centers to improve the efficiency and product selectivity of CH4 oxidation is also discussed.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Naoki Tabata, Takumi Uchino, Chitoshi Kitamura, Kazunari Yoshizawa, Yoshihito Shiota, Shin-ichiro Kato
Summary: We have demonstrated site-selective radical reactions of the stable open-shell singlet diradicaloids DFTh and DFFu with HSn(n-Bu)(3) and azo-based radical initiators. Treatment with HSn(n-Bu)(3) induces hydrogenation at the five-membered ring, while treatment with AIBN induces substitution at the peripheral six-membered rings. One-pot substitution/hydrogenation reactions of DFTh/DFFu with various azo-based radical initiators and HSn(n-Bu)(3) have also been developed. Theoretical calculations reveal the mechanism of these radical reactions and the site-selectivity, which are controlled by the balance of spin density and steric hindrance.
Article
Chemistry, Multidisciplinary
Seiji Ogo, Takeshi Yatabe, Tamon Tome, Riko Takenaka, Yoshihito Shiota, Kenji Kato
Summary: This paper reports a method for the synthesis of H2O2 using a homogeneous catalyst in water, using only H2 and O2 without flammable mixtures or cocatalysts. The catalyst can remove electrons from H2, store them for the reduction of O2, and allow the protonation of the reduced oxygen to form H2O2. The turnover number (TON) is 910 under an H2/O2 (95/5) atmosphere (1.9 MPa) for 12 hours at 23 degrees C, which is the highest among any homogeneous catalysts. Furthermore, a reaction mechanism based on two crystal structures is proposed.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Hiroto Fujisaki, Masaya Okamura, Shiro Hikichi, Takahiko Kojima
Summary: Fe(ii) complexes with pentadentate ligands, including N-heterocyclic carbene moieties, were immobilized onto perfluorinated mesoporous aluminosilicate. These heterogeneous catalysts exhibited excellent performance and selectivity in alkane hydroxylation and cyclohexene epoxidation using H2O2 as the oxidant in CH3CN solvent.
CHEMICAL COMMUNICATIONS
(2023)