Chalcogen bonding in synthesis, catalysis and design of materials Mahmudov, Kamran T; Kopylovich, Maximilian N; Guedes da Silva, M. Fátima C ...
Dalton transactions : an international journal of inorganic chemistry,
08/2017, Letnik:
46, Številka:
31
Journal Article
Recenzirano
Odprti dostop
Chalcogen bonding is a type of noncovalent interaction in which a covalently bonded chalcogen atom (O, S, Se or Te) acts as an electrophilic species towards a nucleophilic (negative) region(s) in ...another or in the same molecule. In general, this interaction is strengthened by the presence of an electron-withdrawing group on the electron-acceptor chalcogen atom and upon moving down in the periodic table of elements, from O to Te. Following a short discussion of the phenomenon of chalcogen bonding, this Perspective presents some demonstrative experimental observations in which this bonding is crucial for synthetic transformations, crystal engineering, catalysis and design of materials as synthons/tectons.
This Perspective highlights the use of chalcogen bonding as a versatile synthon for the synthesis, catalysis and construction of both organic and inorganic materials.
Resonance‐assisted hydrogen bonding (RAHB), a concept introduced by Gilli and co‐workers in 1989, concerns a kind of intramolecular H‐bonding strengthened by a conjugated π‐system, usually in 6‐, 8‐, ...or 10‐membered rings. This Review highlights the involvement of RAHB as a driving force in the synthesis of organic, coordination, and organometallic compounds, as a handy tool in the activation of covalent bonds, and in starting moieties for synthetic transformations. The unique roles of RAHB in molecular recognition and switches, E/Z isomeric resolution, racemization and epimerization of amino acids and chiral amino alcohols, solvatochromism, liquid‐crystalline compounds, and in synthons for crystal engineering and polymer materials are also discussed. The Review can provide practical guidance for synthetic chemists that are interested in exploring and further developing RAHB‐assisted synthesis and design of materials.
That resonates well: Resonance‐assisted hydrogen bonding (RAHB) concerns a kind of intramolecular H‐bonding strengthened by a conjugated π‐system, usually in 6‐, 8‐ or 10‐ membered rings. This Review offers an overview on the role of RAHB in synthetic pathways for the preparation of organic and coordination compounds, as well as on its effects on their properties.
The organocatalytic reduction of C&z.dbd;C and C&z.dbd;N double bonds with biomimetic reductants,
e.g.
Hantzsch 1,4-dihydropyridine esters and benzothiazolines, is reviewed. Very high yields and ...stereoselectivities have been achieved with a variety of catalysts, including chiral amines, thioureas and phosphoric acids, even with loadings equivalent to those of transition metal-catalyzed reactions in some cases. Reductive amination reactions and the dearomatization of heteroaromatic substrates are the subject of more than one half of the contributions. Of lately, methodologies based on kinetic resolution, cascade reactions involving transfer hydrogenation and the development of novel reductants have become prominent in an area which brings great prospects for the future of target oriented-synthesis.
Robust, environmentally friendly reductants enable highly enantioselective reactions in the presence of chiral catalysts.
Alkane Functionalization Pombeiro, Armando J. L; Guedes da Silva, Maria de Fatima Costa
2019, 2018-12-19, 2018-12-28
eBook
Written by a team of leading experts on the topic, the book examines the latest research developments in the synthesis of valuable functionalized organic compounds from alkanes. The authors describe ...the various modes of interaction of alkanes with metal centres and examine theoxidative alkane functionalization upon C-O bond formation. They address the many types of mechanisms, discuss typical catalytic systems and highlight the strategies inspired by biological catalytic systems.
With the increasing population, food toxicity has become a prevalent concern due to the growing contaminants of food products. Therefore, the need for new materials for toxicant detection and food ...quality monitoring will always be in demand. Metal-organic frameworks (MOFs) based on luminescence and electrochemical sensors with tunable porosity and active surface area are promising materials for food contaminants monitoring. This review summarizes and studies the most recent progress on MOF sensors for detecting food contaminants such as pesticides, antibiotics, toxins, biomolecules, and ionic species. First, with the introduction of MOFs, food contaminants and materials for toxicants detection are discussed. Then the insights into the MOFs as emerging materials for sensing applications with luminescent and electrochemical properties, signal changes, and sensing mechanisms are discussed. Next, recent advances in luminescent and electrochemical MOFs food sensors and their sensitivity, selectivity, and capacities for common food toxicants are summarized. Further, the challenges and outlooks are discussed for providing a new pathway for MOF food contaminant detection tools. Overall, a timely source of information on advanced MOF materials provides materials for next-generation food sensors.
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•Metal-organic frameworks (MOFs) are studied for food contaminants monitoring.•Materials for food contaminants detection are discussed.•MOF sensors design and development and analytical performances are discussed.•Advantages, limitations, challenges, and future trends for MOF food sensors are highlighted.
Cross‐dehydrogenative coupling of two C−H bonds or a C−H and an X−H bond (X=N, O, P, S, etc.) has emerged as a powerful new synthetic methodology in the last 12 years. Using this approach, simple ...ethers, often utilized as solvents, and more complex ones, as well as thioethers, have become important alkylating agents, when reacted directly, under oxidative conditions in the presence of suitable reagents. This environmentally friendly, sustainable procedure, has been used to alkylate a wide range of substrates, from simple ketones and acids to alkyl benzenes, coumarins, indoles, oxazoles, benzoxazoles or (benzo)thiazoles and more. This Review is a systematic presentation of the developments in transition metal‐catalyzed CDC reactions, including photoredox processes, which took place between 2014 and early 2018, with an emphasis on the later years.
To alkylate them all: Simple ethers and thioethers can be used to alkylate a variety of substrates, in high yields under mild conditions. The only by‐products are two moles of hydrogen. The literature published in the last 4 years is reviewed herein.
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•COFs/MOFs development, sustainability, reusability, and stabilities are discussed.•COFs/MOFs electrochemical sensors for drugs and pharmaceutical residue are studied.•Strategies to ...improve the detection sensitivity, selectivity, and response time of COFs/MOFs sensors are discussed.•Challenges and outlooks for COFs and MOFs electrochemical sensors are discussed.
Pharmaceutical residues are the undecomposed remains from drugs used in the medical and food industries. Due to their potential adverse effects on human health and natural ecosystems, they are of increasing worldwide concern. The acute detection of pharmaceutical residues can give a rapid examination of their quantity and then prevent them from further contamination. Herein, this study summarizes and discusses the most recent porous covalent-organic frameworks (COFs) and metal–organic frameworks (MOFs) for the electrochemical detection of various pharmaceutical residues. The review first introduces a brief overview of drug toxicity and its effects on living organisms. Subsequently, different porous materials and drug detection techniques are discussed with materials’ properties and applications. Then the development of COFs and MOFs has been addressed with their structural properties and sensing applications. Further, the stability, reusability, and sustainability of MOFs/COFs are reviewed and discussed. Besides, COFs and MOFs’ detection limits, linear ranges, the role of functionalities, and immobilized nanoparticles are analyzed and discussed. Lastly, this review summarized and discussed the MOF@COF composite as sensors, the fabrication strategies to enhance detection potential, and the current challenges in this area.
Intramolecular chalcogen bonding in arylhydrazones of sulfamethizole is strengthened by conjugation in the π‐system of a noncovalent five‐membered ring. The S⋅⋅⋅O distance in the sulfamethizole ...moiety of these compounds ranges from 2.698(3) to 2.806(15) Å, which indicates its strong dependence on the attached arylhydrazone fragments. Information on the nature of the intramolecular chalcogen bond was afforded by DFT calculations.
A new synthon: Three new arylhydrazone dyes have been synthesized and characterized by single‐crystal X‐ray diffraction to investigate the effect of attached substituents on the aromatic moiety of the molecules, highlighting the role of the resonance assisted chalcogen bond synthon in the structural features of these dyes.
A series of new (1
E
,1′
E
)-2,2′-((perfluoro-1,4-phenylene)bis(2,2-dichloroethene-1,1-diyl))bis(1-(
para
-substituted phenyl)diazenes) have been synthesized
via
CuCl catalyzed olefination of the ...corresponding Schiff bases with CCl
4
in the presence of tetramethylethylenediamine (TMEDA) in DMSO. Cl O and Cl F types of halogen bonds were found in these bis-azo dyes, which depend on the electron-donating or -accepting properties of the
para
-substituent (-OCH
3
, -CH
3
, -H, -F) of the azoaromatic ring. DFT calculations demonstrate that noncovalent interactions play a significant role in the stabilization of the intermolecular networks of the structures under study.
A perfluorinated aromatic link was used as a synthon in the design of bis-azo dyes.
Nitrogen ligands Pombeiro, Armando J. L
Dalton transactions : an international journal of inorganic chemistry,
10/2019, Letnik:
48, Številka:
37
Journal Article
Recenzirano
This special web collection of Dalton Transactions focuses on nitrogen ligands, as a tribute to the 150
th
anniversary of the development of the periodic table.
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