Out with Acetonitrile: Water-assisted Accelerated-Aging Synthesis of CuI-Pyrazine Hybrid Materials

2021 ◽  
Author(s):  
Will Lucas ◽  
Feier Hou
Keyword(s):  
Hybrid Materials ◽  
Elevated Temperatures ◽  
Accelerated Aging ◽  
Synthetic Method ◽  
Ambient Conditions ◽  
Reaction Conditions ◽  
Dry Grinding ◽  
Excess Amount ◽  
First Time ◽  
Two Hybrid

CuI and pyrazine form three hybrid materials, [(CuI)2(pyrazine)] (Yellow), [(CuI)2(pyrazine)2] (Orange), and [(CuI)(pyrazine)] (Red). In this work, Red was prepared using a green synthetic method, water-assisted accelerated-aging synthesis, for the first time. The syntheses were performed under ambient conditions with only water and no organic solvents. Depending on the reaction conditions, the other two hybrid materials can be formed as well: Orange was formed immediately after dry grinding CuI and pyrazine, while Yellow can be formed from Red and excess amount of CuI at mildly elevated temperatures. The impacts of temperature and types and amounts of liquid added to the aging mixture on the accelerated-aging synthesis were studied, and mechanisms of the synthesis and interconversions between the three CuI-pyrazine hybrid materials were proposed.

scholarly journals Catalytic activation of ethylene C-H bonds on uniform d8 Ir(I) and Ni(II) cations in zeolites: toward molecular level understanding of ethylene polymerization on heterogeneous catalysts

2019 ◽  
Author(s):  
Nicholas R. Jaegers ◽  
Konstantin Khivantsev ◽  
Libor Kovarik ◽  
Dan Klaus ◽  
Jian Zhi Hu ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Molecular Level ◽  
Ambient Conditions ◽  
Reaction Conditions ◽  
Catalytic Activation ◽  
Dehydrogenative Coupling ◽  
Ethylene Conversion ◽  
Active Metal ◽  
First Time

<div> <p>The homolytic activation of the strong C-H bonds in ethylene is demonstrated, for the first time, on d<sup>8</sup> Ir(I) and Ni(II) single atoms in the cationic positions of zeolites H-FAU and H-BEA under ambient conditions. The oxidative addition of C<sub>2</sub>H<sub>4</sub> to the metal center occurs with the formation of a d<sup>6</sup> metal vinyl hydride, explaining the initiation of the Cossee-Arlman cycle on d<sup>8</sup> M(I/II) sites in the absence of pre-existing M-H bonds. Under mild reaction conditions (80-220ᵒC, 1 bar), the catalytic dimerization to butenes and dehydrogenative coupling of ethylene to butadiene occurs over these catalysts. Butene-1 is not converted to butadiene under the reaction conditions applied. Post-reaction characterization of the two materials reveals that the active metal cations remain site-isolated whereas deactivation occurs due to the formation of carbonaceous deposits on the zeolites. Our findings have significant implications for the molecular level understanding of ethylene conversion and the development of new ways to functionalize C-H bonds under mild conditions.</p> </div>

Activation of Ethylene C-H Bonds on Uniform D8 Ir(I) and Ni(II) Cations in Zeolites: Catalytic Butadiene and Butenes Production Under Mild Conditions

2019 ◽  
Author(s):  
Nicholas R. Jaegers ◽  
Konstantin Khivantsev ◽  
Libor Kovarik ◽  
Dan Klaus ◽  
Jian Zhi Hu ◽  
...  
Keyword(s):  
Molecular Level ◽  
Ambient Conditions ◽  
Reaction Conditions ◽  
Mild Conditions ◽  
Carbonaceous Deposits ◽  
Dehydrogenative Coupling ◽  
Ethylene Conversion ◽  
Active Metal ◽  
First Time

<div> <p>The homolytic activation of the strong C-H bonds in ethylene is demonstrated, for the first time, on d<sup>8</sup> Ir(I) and Ni(II) single atoms in the cationic positions of zeolites H-FAU and H-BEA under ambient conditions. The oxidative addition of C<sub>2</sub>H<sub>4</sub> to the metal center occurs with the formation of a Ir(III) and Ni(IV) vynil hydride, explaining the initiation of the Cossee-Arlman cycle on d<sup>8</sup> M(I/II) sites in the absence of pre-existing M-H bonds. Under mild reaction conditions (80-220ᵒC, 1 bar), the catalytic dimerization to butenes and the unprecedented dehydrogenative coupling of ethylene to butadiene occurs over these catalysts. Butene-1 is not converted to butadiene under the reaction conditions applied. Post-reaction characterization of the two materials reveals that the active metal cations remain site-isolated whereas deactivation occurs due to the formation of carbonaceous deposits on the zeolites. Our findings have significant implications for the molecular level understanding of ethylene conversion and the development of new ways to functionalize C-H bonds under mild conditions.</p> </div>

scholarly journals Catalytic activation of ethylene C-H bonds on uniform d8 Ir(I) and Ni(II) cations in zeolites: toward molecular level understanding of ethylene polymerization on heterogeneous catalysts

2019 ◽  
Author(s):  
Nicholas R. Jaegers ◽  
Konstantin Khivantsev ◽  
Libor Kovarik ◽  
Dan Klaus ◽  
Jian Zhi Hu ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Molecular Level ◽  
Ambient Conditions ◽  
Reaction Conditions ◽  
Catalytic Activation ◽  
Dehydrogenative Coupling ◽  
Ethylene Conversion ◽  
Active Metal ◽  
First Time

<div> <p>The homolytic activation of the strong C-H bonds in ethylene is demonstrated, for the first time, on d<sup>8</sup> Ir(I) and Ni(II) single atoms in the cationic positions of zeolites H-FAU and H-BEA under ambient conditions. The oxidative addition of C<sub>2</sub>H<sub>4</sub> to the metal center occurs with the formation of a d<sup>6</sup> metal vinyl hydride, explaining the initiation of the Cossee-Arlman cycle on d<sup>8</sup> M(I/II) sites in the absence of pre-existing M-H bonds. Under mild reaction conditions (80-220ᵒC, 1 bar), the catalytic dimerization to butenes and dehydrogenative coupling of ethylene to butadiene occurs over these catalysts. Butene-1 is not converted to butadiene under the reaction conditions applied. Post-reaction characterization of the two materials reveals that the active metal cations remain site-isolated whereas deactivation occurs due to the formation of carbonaceous deposits on the zeolites. Our findings have significant implications for the molecular level understanding of ethylene conversion and the development of new ways to functionalize C-H bonds under mild conditions.</p> </div>

Direct Cyclization of Alkenyl Thioester via Transition Metal‐hydrogen Atom Transfer/radical‐polar Crossover Mechanism

2019 ◽  
Author(s):  
Shiori Date ◽  
Kensei Hamasaki ◽  
Karen Sunagawa ◽  
Hiroki Koyama ◽  
Chikayoshi Sebe ◽  
...  
Keyword(s):  
Natural Products ◽  
Hydrogen Atom ◽  
Transition Metal ◽  
Hydrogen Atom Transfer ◽  
Synthetic Method ◽  
Atom Transfer ◽  
Reaction Conditions ◽  
Hydride Hydrogen ◽  
Sulfur Heterocycles ◽  
One Step

<div>We report here a catalytic, Markovnikov selective, and scalable synthetic method for the synthesis of saturated sulfur heterocycles, which are found in the structures of pharmaceuticals and natural products, in one step from an alkenyl thioester. Unlike a potentially labile alkenyl thiol, an alkenyl thioester is stable and easy to prepare. The powerful Co catalysis via a cobalt hydride hydrogen atom transfer and radical-polar crossover mechanism enabled simultaneous cyclization and deprotection. The substrate scope was expanded by the extensive optimization of the reaction conditions and tuning of the thioester unit.</div>

scholarly journals A Sustainable Improvement of ω-Bromoalkylphosphonates Synthesis to Access Novel KuQuinones

Organics ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 107-117
Author(s):  
Mattia Forchetta ◽  
Valeria Conte ◽  
Giulia Fiorani ◽  
Pierluca Galloni ◽  
Federica Sabuzi
Keyword(s):  
Metal Oxides ◽  
Phosphonic Acid ◽  
Organic Molecules ◽  
Building Blocks ◽  
Reaction Conditions ◽  
Phosphonic Acids ◽  
Sustainable Improvement ◽  
Phosphonate Esters ◽  
First Time ◽  
Complex Organic

Owing to the attractiveness of organic phosphonic acids and esters in the pharmacological field and in the functionalization of conductive metal-oxides, the research of effective synthetic protocols is pivotal. Among the others, ω-bromoalkylphosphonates are gaining particular attention because they are useful building blocks for the tailored functionalization of complex organic molecules. Hence, in this work, the optimization of Michaelis–Arbuzov reaction conditions for ω-bromoalkylphosphonates has been performed, to improve process sustainability while maintaining good yields. Synthesized ω-bromoalkylphosphonates have been successfully adopted for the synthesis of new KuQuinone phosphonate esters and, by hydrolysis, phosphonic acid KuQuinone derivatives have been obtained for the first time. Considering the high affinity with metal-oxides, KuQuinones bearing phosphonic acid terminal groups are promising candidates for biomedical and photo(electro)chemical applications.

Sulfonyl Radical Triggered Selective Iodosulfonylation and Bicycli-zations of 1,6-Dienes

2021 ◽  
Author(s):  
Shi-Ping Wu ◽  
Dong-Kai Wang ◽  
Qing-Qing Kang ◽  
Guo-Ping Ge ◽  
Hongxing Zheng ◽  
...  
Keyword(s):  
Functional Group ◽  
High Selectivity ◽  
Reaction Conditions ◽  
First Time

A novel sulfonyl radical triggered selective iodosulfonylation and bicyclizations of 1,6-dienes has been described for the first time. High selectivity and efficiency, mild reaction conditions, excellent functional group compatibility, and...

scholarly journals Recent advances in the electrochemical construction of heterocycles

2014 ◽  
Vol 10 ◽  
pp. 2858-2873 ◽  
Author(s):  
Robert Francke
Keyword(s):  
Heterocyclic Compounds ◽  
Elevated Temperatures ◽  
Ring Formation ◽  
Environmentally Benign ◽  
Heterocyclic Chemistry ◽  
Ambient Conditions ◽  
Recent Developments ◽  
Strong Acids ◽  
Selection Of ◽  
Made In

Due to the fact that the major portion of pharmaceuticals and agrochemicals contains heterocyclic units and since the overall number of commercially used heterocyclic compounds is steadily growing, heterocyclic chemistry remains in the focus of the synthetic community. Enormous efforts have been made in the last decades in order to render the production of such compounds more selective and efficient. However, most of the conventional methods for the construction of heterocyclic cores still involve the use of strong acids or bases, the operation at elevated temperatures and/or the use of expensive catalysts and reagents. In this regard, electrosynthesis can provide a milder and more environmentally benign alternative. In fact, numerous examples for the electrochemical construction of heterocycles have been reported in recent years. These cases demonstrate that ring formation can be achieved efficiently under ambient conditions without the use of additional reagents. In order to account for the recent developments in this field, a selection of representative reactions is presented and discussed in this review.

Recent results in trapped-ion quantum computing at NIST

2001 ◽  
Vol 1 (Special) ◽  
pp. 113-123
Author(s):  
D. Kielpinski ◽  
A. Ben-Kish ◽  
J. Britton ◽  
V. Meyer ◽  
M.A. Rowe ◽  
...  
Keyword(s):  
The State ◽  
Entangled State ◽  
Bell’S Inequality ◽  
Ambient Conditions ◽  
Bell's Inequality ◽  
Quantum Register ◽  
Sigma Level ◽  
Universal Quantum ◽  
Encoding Method ◽  
First Time

We review recent experiments on entanglement, Bell's inequality, and decoherence-free subspaces in a quantum register of trapped {9Be+} ions. We have demonstrated entanglement of up to four ions using the technique of Molmer and Sorensen. This method produces the state ({|\uparrow\uparrow\rangle}+{|\downarrow\downarrow\rangle})/\sqrt{2} for two ions and the state ({\downarrow}{\downarrow}{\downarrow}{\downarrow} \rangle + | {\uparrow}{\uparrow}{\uparrow}{\uparrow} \rangle)/\sqrt{2} for four ions. We generate the entanglement deterministically in each shot of the experiment. Measurements on the two-ion entangled state violates Bell's inequality at the 8\sigma level. Because of the high detector efficiency of our apparatus, this experiment closes the detector loophole for Bell's inequality measurements for the first time. This measurement is also the first violation of Bell's inequality by massive particles that does not implicitly assume results from quantum mechanics. Finally, we have demonstrated reversible encoding of an arbitrary qubit, originally contained in one ion, into a decoherence-free subspace (DFS) of two ions. The DFS-encoded qubit resists applied collective dephasing noise and retains coherence under ambient conditions 3.6 times longer than does an unencoded qubit. The encoding method, which uses single-ion gates and the two-ion entangling gate, demonstrates all the elements required for two-qubit universal quantum logic.

scholarly journals Temperature and UV light affect the activity of marine cell-free enzymes

2017 ◽  
Vol 14 (17) ◽  
pp. 3971-3977 ◽  
Author(s):  
Blair Thomson ◽  
Christopher David Hepburn ◽  
Miles Lamare ◽  
Federico Baltar
Keyword(s):  
Organic Matter ◽  
Extracellular Enzymes ◽  
Elevated Temperatures ◽  
Uv Light ◽  
Control Mechanisms ◽  
Potential Control ◽  
Control Factors ◽  
Rate Limiting Step ◽  
Ocean Environment ◽  
First Time

Abstract. Microbial extracellular enzymatic activity (EEA) is the rate-limiting step in the degradation of organic matter in the oceans. These extracellular enzymes exist in two forms: cell-bound, which are attached to the microbial cell wall, and cell-free, which are completely free of the cell. Contrary to previous understanding, cell-free extracellular enzymes make up a substantial proportion of the total marine EEA. Little is known about these abundant cell-free enzymes, including what factors control their activity once they are away from their sites (cells). Experiments were run to assess how cell-free enzymes (excluding microbes) respond to ultraviolet radiation (UVR) and temperature manipulations, previously suggested as potential control factors for these enzymes. The experiments were done with New Zealand coastal waters and the enzymes studied were alkaline phosphatase (APase), β-glucosidase, (BGase), and leucine aminopeptidase (LAPase). Environmentally relevant UVR (i.e. in situ UVR levels measured at our site) reduced cell-free enzyme activities by up to 87 % when compared to controls, likely a consequence of photodegradation. This effect of UVR on cell-free enzymes differed depending on the UVR fraction. Ambient levels of UV radiation were shown to reduce the activity of cell-free enzymes for the first time. Elevated temperatures (15 °C) increased the activity of cell-free enzymes by up to 53 % when compared to controls (10 °C), likely by enhancing the catalytic activity of the enzymes. Our results suggest the importance of both UVR and temperature as control mechanisms for cell-free enzymes. Given the projected warming ocean environment and the variable UVR light regime, it is possible that there could be major changes in the cell-free EEA and in the enzymes contribution to organic matter remineralization in the future.

scholarly journals The Eschenmoser coupling reaction under continuous-flow conditions

2011 ◽  
Vol 7 ◽  
pp. 1164-1172 ◽  
Author(s):  
Sukhdeep Singh ◽  
J Michael Köhler ◽  
Andreas Schober ◽  
G Alexander Groß
Keyword(s):  
Continuous Flow ◽  
Elevated Temperatures ◽  
Reaction Times ◽  
Coupling Reaction ◽  
Flow Chemistry ◽  
Flow Conditions ◽  
Reaction Conditions ◽  
Bond Forming ◽  
Carbon Carbon Bond ◽  
Reaction Proceeds

The Eschenmoser coupling is a useful carbon–carbon bond forming reaction which has been used in various different synthesis strategies. The reaction proceeds smoothly if S-alkylated ternary thioamides or thiolactames are used. In the case of S-alkylated secondary thioamides or thiolactames, the Eschenmoser coupling needs prolonged reaction times and elevated temperatures to deliver valuable yields. We have used a flow chemistry system to promote the Eschenmoser coupling under enhanced reaction conditions in order to convert the demanding precursors such as S-alkylated secondary thioamides and thiolactames in an efficient way. Under pressurized reaction conditions at about 220 °C, the desired Eschenmoser coupling products were obtained within 70 s residence time. The reaction kinetics was investigated and 15 examples of different building block combinations are given.

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