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Shin Aoki - One of the best experts on this subject based on the ideXlab platform.
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catalytic hydrolysis of Phosphate monoester by supramolecular phosphatases formed from a monoalkylated dizinc ii complex cyclic diimide units and copper ii in two phase solvent system
Inorganic Chemistry, 2019Co-Authors: Akib Bin Rahman, Hiroki Imafuku, Yuya Miyazawa, Ananda Kafle, Yutaka Saga, Hideki Sakai, Shin AokiAbstract:Design and synthesis of enzyme mimic with programmed molecular interaction among several building blocks including metal complexes and metal chelators is of intellectual and practical significance. The preparation of artificial enzymes that mimic the natural enzymes such as hydrolases, phosphatases, etc. remains a great challenge in the field of supramolecular chemistry. Herein we report on the design and synthesis of asymmetric (nonsymmetric) supermolecules by the 2:2:2 self-assembly of an amphiphilic zinc(II)–cyclen complex containing a 2,2′-bipyridyl linker and one long alkyl chain (Zn2L3), barbital analogues, and Cu2+ as model compounds of an enzyme alkaline phosphatase that catalyzes the hydrolysis of Phosphate monoesters such as mono(4-Nitrophenyl)Phosphate at neutral pH in two-phase solvent system (H2O/CHCl3) in pH 7.4 and 37 °C. Hydrolytic activity of these complexes was found to be catalytic, and their catalytic turnover numbers are 3–4. The mechanistic studies based on the UV/vis and emission sp...
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Catalytic Hydrolysis of Phosphate Monoester by Supramolecular Phosphatases Formed from a Monoalkylated Dizinc(II) Complex, Cyclic Diimide Units, and Copper(II) in Two-Phase Solvent System
2019Co-Authors: Akib Bin Rahman, Hiroki Imafuku, Yuya Miyazawa, Ananda Kafle, Yutaka Saga, Hideki Sakai, Shin AokiAbstract:Design and synthesis of enzyme mimic with programmed molecular interaction among several building blocks including metal complexes and metal chelators is of intellectual and practical significance. The preparation of artificial enzymes that mimic the natural enzymes such as hydrolases, phosphatases, etc. remains a great challenge in the field of supramolecular chemistry. Herein we report on the design and synthesis of asymmetric (nonsymmetric) supermolecules by the 2:2:2 self-assembly of an amphiphilic zinc(II)–cyclen complex containing a 2,2′-bipyridyl linker and one long alkyl chain (Zn2L3), barbital analogues, and Cu2+ as model compounds of an enzyme alkaline phosphatase that catalyzes the hydrolysis of Phosphate monoesters such as mono(4-Nitrophenyl)Phosphate at neutral pH in two-phase solvent system (H2O/CHCl3) in pH 7.4 and 37 °C. Hydrolytic activity of these complexes was found to be catalytic, and their catalytic turnover numbers are 3–4. The mechanistic studies based on the UV/vis and emission spectra of the H2O and CHCl3 phases of the reaction mixtures suggest that the hydrophilicity/hydrophobicity balance of the supramolecular catalysts is an important factor for catalytic activity
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supramolecular phosphatases formed by the self assembly of the bis zn2 cyclen complex copper ii and barbital derivatives in water
Chemistry-an Asian Journal, 2014Co-Authors: Yuya Miyazawa, Mohd Zulkefeli, Yosuke Hisamatsu, Asami Suzuki, Motoo Shiro, Shin AokiAbstract:In our previous paper, we reported that a dimeric Zn(2+) complex with a 2,2'-bipyridyl linker (Zn2L(1)), cyanuric acid (CA), and a Cu(2+) ion automatically assemble in aqueous solution to form 4:4:4 complex 3, which selectively catalyzes the hydrolysis of mono(4-Nitrophenyl)Phosphate (MNP) at neutral pH. Herein, we report that the use of barbital (Bar) instead of CA for the self-assembly with Zn2L(1) and Cu(2+) induces 2:2:2 complexation of these components, and not the 4:4:4 complex, to form supramolecular complex 6 a, the structure and equilibrium characteristics of which were studied by analytical and physical measurements. The finding show that 6 a also accelerates the hydrolysis of MNP, similarly to 3. Moreover, inspired by the crystal structure of 6 a, we prepared barbital units that contain functional groups on their side chains in an attempt to produce supramolecular phosphatases that possess functional groups near the Cu2(μ-OH)2 catalytic core so as to mimic the catalytic center of alkaline phosphatase (AP).
Omar K Farha - One of the best experts on this subject based on the ideXlab platform.
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rapid biomimetic degradation of a nerve agent simulant by incorporating imidazole bases into a metal organic framework
ACS Catalysis, 2021Co-Authors: Hongbin Luo, Omar K Farha, Anthony J Castro, Megan C Wasson, Willmer I Flores, Yangyang LiuAbstract:Metal-organic frameworks (MOFs) are excellent catalytic materials for the hydrolytic degradation of nerve agents and their simulants. However, most of the MOF-based hydrolysis catalysts to date are reliant on liquid water media buffered by a volatile liquid base. To overcome this practical limitation, we developed a simple and feasible strategy to synthesize MOF composites that structurally mimic phosphotriesterase's active site as well as its ligated histidine residues. By incorporating imidazole and its derivative into the pores of MOF-808, the obtained MOF composites achieved rapid degradation of a nerve agent simulant (dimethyl-4-Nitrophenyl Phosphate, DMNP) in pure water as well as in a humid environment without liquid base. Remarkably, one of the composites Im@MOF-808 displayed the highest catalytic activity for DMNP hydrolysis in unbuffered aqueous solutions among all reported MOF-based catalysts. Furthermore, solid-phase catalysis showed that Im@MOF-808 can also rapidly hydrolyze DMNP under high-humidity conditions without bulk water or external bases. This work provides a viable solution toward the implementation of MOF materials into protective equipment for practical nerve agent detoxification.
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dual function metal organic framework as a versatile catalyst for detoxifying chemical warfare agent simulants
ACS Nano, 2015Co-Authors: Suyoung Moon, Joseph T. Hupp, Omar K FarhaAbstract:The nanocrystals of a porphyrin-based zirconium(IV) metal–organic framework (MOF) are used as a dual-function catalyst for the simultaneous detoxification of two chemical warfare agent simulants at room temperature. Simulants of nerve agent (such as GD, VX) and mustard gas, dimethyl 4-Nitrophenyl Phosphate and 2-chloroethyl ethyl sulfide, have been hydrolyzed and oxidized, respectively, to nontoxic products via a pair of pathways catalyzed by the same MOF. Phosphotriesterase-like activity of the Zr6-containing node combined with photoactivity of the porphyrin linker gives rise to a versatile MOF catalyst. In addition, bringing the MOF crystals down to the nanoregime leads to acceleration of the catalysis.
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Dual-Function Metal–Organic Framework as a Versatile Catalyst for Detoxifying Chemical Warfare Agent Simulants
2015Co-Authors: Yangyang Liu, Suyoung Moon, Joseph T. Hupp, Omar K FarhaAbstract:The nanocrystals of a porphyrin-based zirconium(IV) metal–organic framework (MOF) are used as a dual-function catalyst for the simultaneous detoxification of two chemical warfare agent simulants at room temperature. Simulants of nerve agent (such as GD, VX) and mustard gas, dimethyl 4-Nitrophenyl Phosphate and 2-chloroethyl ethyl sulfide, have been hydrolyzed and oxidized, respectively, to nontoxic products via a pair of pathways catalyzed by the same MOF. Phosphotriesterase-like activity of the Zr6-containing node combined with photoactivity of the porphyrin linker gives rise to a versatile MOF catalyst. In addition, bringing the MOF crystals down to the nanoregime leads to acceleration of the catalysis
Stan R Brown - One of the best experts on this subject based on the ideXlab platform.
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investigation of the effect of oxy bridging groups in dinuclear zn ii complexes that catalyze the cleavage of a simple Phosphate diester rna analogue
Inorganic Chemistry, 2009Co-Authors: Mark F Mohamed, Alexei A Neverov, Stan R BrownAbstract:Two sets of dinuclear Zn(II) complexes were prepared to determine the effect of the presence of oxyanionic bridging groups between the metal centers on the catalytic activity toward the methanolysis of the RNA analogue 2-hydroxypropyl-4-Nitrophenyl Phosphate (HPNPP, 2). The Zn(II)2 complexes of bis(di-(2-pyridylmethyl)amino)-m-xylene (6) and 2,6-bis(di-(2-pyridylmethyl)amino)-4-methylphenol (7) were compared to assess the effect of a bridging phenoxide ligand, while the Zn(II)2 complex of 1,3-bis-N1-(1,5,9-triazacyclododecyl)-propan-2-ol (8) was prepared to determine the effect of the 2-propoxy group compared to the previously studied complex of 1,3-bis-N1-(1,5,9-triazacyclododecyl)-propane (4). Detailed kinetic studies of the cleavage of 2 including kobs vs [catalyst] plots and sspH-rate profiles were performed for each system along with potentiometric titration experiments to determine the acid dissociation constants for the catalytically relevant groups. The results show that inclusion of the phenoxy b...
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enzyme like acceleration for the hydrolysis of a dna model promoted by a dinuclear zn ii catalyst in dilute aqueous ethanol
Journal of the American Chemical Society, 2008Co-Authors: Tony C Liu, Alexei A Neverov, Stan R BrownAbstract:The rates and products of cleavage of methyl (2-chloro-4-Nitrophenyl) Phosphate (2) promoted by a dinuclear Zn(II) complex (3) of 1,3-bis-N,N'(1,5,9-triazacyclododecyl)propane along with 1 equiv of ethoxide were investigated in ethanol solution containing small amounts of water (8 mM or=1.6 x 10(17) times relative to the background hydroxide reaction, suggesting that complex 3 promotes the hydrolysis at least 1000 times more effectively than ethanolysis.
Yuya Miyazawa - One of the best experts on this subject based on the ideXlab platform.
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catalytic hydrolysis of Phosphate monoester by supramolecular phosphatases formed from a monoalkylated dizinc ii complex cyclic diimide units and copper ii in two phase solvent system
Inorganic Chemistry, 2019Co-Authors: Akib Bin Rahman, Hiroki Imafuku, Yuya Miyazawa, Ananda Kafle, Yutaka Saga, Hideki Sakai, Shin AokiAbstract:Design and synthesis of enzyme mimic with programmed molecular interaction among several building blocks including metal complexes and metal chelators is of intellectual and practical significance. The preparation of artificial enzymes that mimic the natural enzymes such as hydrolases, phosphatases, etc. remains a great challenge in the field of supramolecular chemistry. Herein we report on the design and synthesis of asymmetric (nonsymmetric) supermolecules by the 2:2:2 self-assembly of an amphiphilic zinc(II)–cyclen complex containing a 2,2′-bipyridyl linker and one long alkyl chain (Zn2L3), barbital analogues, and Cu2+ as model compounds of an enzyme alkaline phosphatase that catalyzes the hydrolysis of Phosphate monoesters such as mono(4-Nitrophenyl)Phosphate at neutral pH in two-phase solvent system (H2O/CHCl3) in pH 7.4 and 37 °C. Hydrolytic activity of these complexes was found to be catalytic, and their catalytic turnover numbers are 3–4. The mechanistic studies based on the UV/vis and emission sp...
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Catalytic Hydrolysis of Phosphate Monoester by Supramolecular Phosphatases Formed from a Monoalkylated Dizinc(II) Complex, Cyclic Diimide Units, and Copper(II) in Two-Phase Solvent System
2019Co-Authors: Akib Bin Rahman, Hiroki Imafuku, Yuya Miyazawa, Ananda Kafle, Yutaka Saga, Hideki Sakai, Shin AokiAbstract:Design and synthesis of enzyme mimic with programmed molecular interaction among several building blocks including metal complexes and metal chelators is of intellectual and practical significance. The preparation of artificial enzymes that mimic the natural enzymes such as hydrolases, phosphatases, etc. remains a great challenge in the field of supramolecular chemistry. Herein we report on the design and synthesis of asymmetric (nonsymmetric) supermolecules by the 2:2:2 self-assembly of an amphiphilic zinc(II)–cyclen complex containing a 2,2′-bipyridyl linker and one long alkyl chain (Zn2L3), barbital analogues, and Cu2+ as model compounds of an enzyme alkaline phosphatase that catalyzes the hydrolysis of Phosphate monoesters such as mono(4-Nitrophenyl)Phosphate at neutral pH in two-phase solvent system (H2O/CHCl3) in pH 7.4 and 37 °C. Hydrolytic activity of these complexes was found to be catalytic, and their catalytic turnover numbers are 3–4. The mechanistic studies based on the UV/vis and emission spectra of the H2O and CHCl3 phases of the reaction mixtures suggest that the hydrophilicity/hydrophobicity balance of the supramolecular catalysts is an important factor for catalytic activity
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supramolecular phosphatases formed by the self assembly of the bis zn2 cyclen complex copper ii and barbital derivatives in water
Chemistry-an Asian Journal, 2014Co-Authors: Yuya Miyazawa, Mohd Zulkefeli, Yosuke Hisamatsu, Asami Suzuki, Motoo Shiro, Shin AokiAbstract:In our previous paper, we reported that a dimeric Zn(2+) complex with a 2,2'-bipyridyl linker (Zn2L(1)), cyanuric acid (CA), and a Cu(2+) ion automatically assemble in aqueous solution to form 4:4:4 complex 3, which selectively catalyzes the hydrolysis of mono(4-Nitrophenyl)Phosphate (MNP) at neutral pH. Herein, we report that the use of barbital (Bar) instead of CA for the self-assembly with Zn2L(1) and Cu(2+) induces 2:2:2 complexation of these components, and not the 4:4:4 complex, to form supramolecular complex 6 a, the structure and equilibrium characteristics of which were studied by analytical and physical measurements. The finding show that 6 a also accelerates the hydrolysis of MNP, similarly to 3. Moreover, inspired by the crystal structure of 6 a, we prepared barbital units that contain functional groups on their side chains in an attempt to produce supramolecular phosphatases that possess functional groups near the Cu2(μ-OH)2 catalytic core so as to mimic the catalytic center of alkaline phosphatase (AP).
Seth M Cohen - One of the best experts on this subject based on the ideXlab platform.
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high throughput screening of mofs for breakdown of v series nerve agents
ACS Applied Materials & Interfaces, 2020Co-Authors: Joseph M Palomba, Mark Kalaj, Steven P. Harvey, Brian R Pimentel, Jared B Decoste, Gregory W Peterson, Seth M CohenAbstract:Metal-organic frameworks (MOFs) have shown promise for the catalytic decomposition of chemical weapons. Finding the best materials for the degradation of nerve agents requires the ability to screen a high number of samples and elucidate the key parameters of effective catalysis. In this work, a high-throughput screening (HTS) method has been developed to evaluate MOFs as catalysts, specifically against the V-class of nerve agents. Over 100 MOFs have been tested using the V-class simulant, O,O-diethyl S-phenyl phosphorothioate (DEPPT), revealing good activity for some UiO-66 derivatives. A medium-throughput hydrolysis assay for the nerve agent O-ethyl S-[2-(diisopropylamino)ethyl]methylphosphonothioate (VX) was also performed using six MOFs selected from HTS and was validated by 31P NMR. The results demonstrated that the DEPPT-based assay is a good indicator of V-series agent reactivity and should be considered in addition to the common (4-Nitrophenyl)Phosphate (DMNP) assay that is used for G-series agents.
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halogen bonding in uio 66 frameworks promotes superior chemical warfare agent simulant degradation
Chemical Communications, 2019Co-Authors: Mark Kalaj, Joseph M Palomba, Kyle C Bentz, M R Momeni, Kyle S Barcus, Francesco Paesani, Seth M CohenAbstract:Herein, a series of halogenated UiO-66 derivatives was synthesized and analyzed for the breakdown of the chemical warfare agent simulant dimethyl-4-Nitrophenyl Phosphate (DMNP) to analyze ligand effects. UiO-66-I degrades DMNP at a rate four times faster than the most active previously reported MOFs. MOF defects were quantified and ruled out as a cause for increased activity. Theoretical calculations suggest the enhanced activity of UiO-66-I originates from halogen bonding of the iodine atom to the phosphoester linkage allowing for more rapid hydrolysis of the P–O bond.
