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Fluorocarbons are chemical compounds with carbon-fluorine bonds. Compounds that contain many C-F bonds often has distinctive properties, e.g., enhanced stability, volatility, and hydrophobicity. Fluorocarbons and their derivatives are commercial polymers, refrigerants, drugs, and anesthetics.
In organometallic chemistry, organolithium reagents are chemical compounds that contain carbon–lithium (C–Li) bonds. These reagents are important in organic synthesis, and are frequently used to transfer the organic group or the lithium atom to the substrates in synthetic steps, through nucleophilic addition or simple deprotonation. Organolithium reagents are used in industry as an initiator for anionic polymerization, which leads to the production of various elastomers. They have also been applied in asymmetric synthesis in the pharmaceutical industry. Due to the large difference in electronegativity between the carbon atom and the lithium atom, the C−Li bond is highly ionic. Owing to the polar nature of the C−Li bond, organolithium reagents are good nucleophiles and strong bases. For laboratory organic synthesis, many organolithium reagents are commercially available in solution form. These reagents are highly reactive, and are sometimes pyrophoric.
Supramolecular chemistry refers to the branch of chemistry concerning chemical systems composed of a discrete number of molecules. The strength of the forces responsible for spatial organization of the system range from weak intermolecular forces, electrostatic charge, or hydrogen bonding to strong covalent bonding, provided that the electronic coupling strength remains small relative to the energy parameters of the component. While traditional chemistry concentrates on the covalent bond, supramolecular chemistry examines the weaker and reversible non-covalent interactions between molecules. These forces include hydrogen bonding, metal coordination, hydrophobic forces, van der Waals forces, pi–pi interactions and electrostatic effects.
The term molecular recognition refers to the specific interaction between two or more molecules through noncovalent bonding such as hydrogen bonding, metal coordination, hydrophobic forces, van der Waals forces, π-π interactions, halogen bonding, or resonant interaction effects. In addition to these direct interactions, solvents can play a dominant indirect role in driving molecular recognition in solution. The host and guest involved in molecular recognition exhibit molecular complementarity. Exceptions are molecular containers, including e.g. nanotubes, in which portals essentially control selectivity.
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CrystEngComm is a peer-reviewed online-only scientific journal publishing original research and review articles on all aspects of crystal engineering including properties, polymorphism, target materials, and crystalline nanomaterials. It is published biweekly by the Royal Society of Chemistry and the editor-in-chief is Pierangelo Metrangolo. According to the Journal Citation Reports, the journal has a 2020 impact factor of 3.545. CrystEngComm has a close association with the virtual web community, CrystEngCommunity.
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In chemistry, molecular oxohalides (oxyhalides) are a group of chemical compounds in which both oxygen and halogen atoms are attached to another chemical element A in a single molecule. They have the general formula AOmXn, where X = fluorine (F), chlorine (Cl), bromine (Br), and/or iodine (I). The element A may be a main group element, a transition element or an actinide. The term oxohalide, or oxyhalide, may also refer to minerals and other crystalline substances with the same overall chemical formula, but having an ionic structure.
Hydrodefluorination (HDF) is a type of organic reaction in which in a substrate of a carbon–fluorine bond is replaced by a carbon–hydrogen bond. The topic is of some interest to scientific research. In one general strategy for the synthesis of fluorinated compounds with a specific substitution pattern, the substrate is a cheaply available perfluorinated hydrocarbon. An example is the conversion of hexafluorobenzene (C6F6) to pentafluorobenzene (C6F5H) by certain zirconocene hydrido complexes. In this type of reaction the thermodynamic driving force is the formation of a metal-fluorine bond that can offset the cleavage of the very stable C-F bond. Other substrates that have been investigated are fluorinated alkenes. Another reaction type is oxidative addition of a metal into a C-F bond followed by a reductive elimination step in presence of a hydrogen source. For example, perfluoronated pyridine reacts with bis(cyclooctadiene)nickel(0) and triethylphosphine to the oxidative addition product and then with HCl to the ortho-hydrodefluorinated product. In reductive hydrodefluorination the fluorocarbon is reduced in a series of single electron transfer steps through the radical anion, the radical and the anion with ultimate loss of a fluorine anion. An example is the conversion of pentafluorobenzoic acid to 3,4,5-tetrafluorobenzoic acid in a reaction of zinc dust in aqueous ammonia.
Fluorine forms a great variety of chemical compounds, within which it always adopts an oxidation state of −1. With other atoms, fluorine forms either polar covalent bonds or ionic bonds. Most frequently, covalent bonds involving fluorine atoms are single bonds, although at least two examples of a higher order bond exist. Fluoride may act as a bridging ligand between two metals in some complex molecules. Molecules containing fluorine may also exhibit hydrogen bonding. Fluorine's chemistry includes inorganic compounds formed with hydrogen, metals, nonmetals, and even noble gases; as well as a diverse set of organic compounds. For many elements the highest known oxidation state can be achieved in a fluoride. For some elements this is achieved exclusively in a fluoride, for others exclusively in an oxide; and for still others the highest oxidation states of oxides and fluorides are always equal.
Pierangelo Metrangolo is an Italian chemist with interests in supramolecular chemistry and functional materials. He also has an interest in crystal engineering, in particular by using the halogen bond. He is Vice-President and President-Elect of the Physical and Biophysical Chemistry Division of IUPAC.
The European Symposium on Fluorine Chemistry (ESFC) is a triennial academic conference on Fluorine chemistry founded in 1965. The conference is held in Europe, but traditionally it brings together the fluorine community from all over the world. The scientific programme of the Symposium covers all the areas of fluorine chemistry relevant to fundamental and applied research.
A chalcogen bond (ChB) is an attractive interaction in the family of σ-hole interactions, along with halogen bonds. Electrostatic, charge-transfer (CT) and dispersion terms have been identified as contributing to this type of interaction. In terms of CT contribution, this family of attractive interactions has been modeled as an electron donor ) interacting with the σ* orbital of a C-X bond of the bond donor. In terms of electrostatic interactions, the molecular electrostatic potential (MEP) maps is often invoked to visualize the electron density of the donor and an electrophilic region on the acceptor, where the potential is depleted, referred to as a σ-hole. ChBs, much like hydrogen and halogen bonds, have been invoked in various non-covalent interactions, such as protein folding, crystal engineering, self-assembly, catalysis, transport, sensing, templation, and drug design.
Dmitrii "Dima" F. Perepichka is the Chair of Chemistry Department and Sir William C. MacDonald Chair Professor in Chemistry at McGill University. His research interest are primarily in the area of organic electronics. He has contributed in the understanding of structural electronics effects of organic conjugated materials at molecular, supramolecular, and macromolecular levels via the study of small molecules, supramolecular (co-)assemblies, polymers, covalent organic frameworks, and on-surface assemblies/polymers.
Diiodoacetylene is the organoiodine compound with the formula C2I2. It is a white, volatile solid that dissolves in organic solvents. It is prepared by iodination of trimethylsilylacetylene. Although samples explode above 80 °C, diiodoacetylene is the most readily handled of the dihaloacetylenes. Dichloroacetylene, for example, is more volatile and more explosive. As confirmed by X-ray crystallography, diiodoacetylene is linear. It is however a shock, heat and friction sensitive compound. Like other haloalkynes, diiodoacetylene is a strong halogen bond donor.
Sigma hole Interactions are a family of intermolecular forces that can occur between several classes of molecules and arise from an energetically stabilizing interaction between a positively charged site, termed a sigma hole, and a negatively charge site, typically a lone pair, on different atoms that are not covalently bonded to each other. These interactions are usually rationalized primarily via dispersion and electrostatic charge-transfer, and are characterized by a strong directional preference that makes them useful in applications in which control over supramolecular chemistry is desired.
References
- ↑ "RCS News, June 2011, pag. 30: RCS-SCI Award to Giuseppe Resnati" (PDF).
- ↑ Halogen Bonding: Fundamentals and Applications Metrangolo, P. and Resnati, G. Eds.; 2008; Springer; Berlin, Heidelberg, New York. ISBN 978-3-540-74329-3
- ↑ G. Resnati et al. The Chalcogen Bond in Crystalline Solids: A World Parallel to Halogen Bond Accounts of Chemical Research 2019, 52, 1311-1324 (DOI: org/10.1021/acs.accounts.9b00037)
- ↑ G. Resnati Synthesis of Chiral and Bioactive Fluoroorganic Compounds Tetrahedron 1993, 49, 9385-9445 (DOI:10.1016/S00404020(01)80212-X)
- ↑ G. Resnati et al. Perfluorinated Oxaziridines: Synthesis and Reactivity Chemical Reviews 1996, 96, 1809-1824 (DOI: 10.1021/cr941146h)
- ↑ G. Resnati et al. 19F Magnetic Resonance Imaging (MRI): From Design of Materials to Clinical Applications Chemical Reviews 2015, 115, 1106−1129 (DOI: org/10.1021/cr500286d)
- ↑ "Resnati coordinated an IUPAC project on crystal engineering".
- ↑ G. Resnati et al. Halogen Bonding in Supramolecular Chemistry Angew. Chem. Int. Ed. 2008, 47, 6114-6127 ( DOI: 10.1002/anie.200800128 )
- ↑ G. Resnati et al. Halogen bonded Borromean networks by design: topology invariance and metric tuning in a library of multi-component systems Chemical Sci. 2017 ( DOI: 10.1039/C6SC04478F )
- ↑ G. Resnati et al. Halogen Bonding Based Recognition Processes: A World Parallel to Hydrogen Bonding Acc. Chem. Res. 2005, 38, 386-395 (DOI: 10.1021/ar0400995 )
- ↑ G. Resnati et al. An Adaptable and Dynamically Porous Organic Salt Traps Unique Tetrahalide Dianions Angew. Chem. Int. Ed. 2013, 52, 13444-13448 ( DOI: 10.1002/anie.201307552 )
- ↑ G. Resnati et al. Halogen-bonding-triggered supramolecular gel formation Nature Chem. 2013, 5, 42-47 ( DOI:10.1038/nchem.1496 )
- ↑ Halogen Bonding I - Impact on Materials Chemistry and Life Sciences Metrangolo P. and Resnati G. Eds.; 2014; Springer; Berlin, Heidelberg, New York. ISBN 978-3-319-14056-8
- ↑ Halogen Bonding II - Impact on Materials Chemistry and Life Sciences Metrangolo P. and Resnati G. Eds.; 2015; Springer; Berlin, Heidelberg, New York. ISBN 978-3-319-15731-3
- ↑ "ICNI-2022, The van der Waals Prize".
- ↑ "RCS News, June 2011, pag. 30: RCS-SCI Award to Giuseppe Resnati" (PDF).
- ↑ "Intermolecular Interactions and Structural Aspects in Organic Chemistry awards" (PDF).
- ↑ "Academy of Europe: Resnati Giuseppe".
- ↑ Journal of Fluorine Chemistry: Editorial Board.
- ↑ Rogers, Robin D. (2012). "Crystal Growth & Design Around the World in 2012, DOI:10.1021/cg201654d". Crystal Growth & Design. 12: 1–2. doi:10.1021/cg201654d.
- ↑ "ISXB-1".
- ↑ "Official Web-site of the Faraday Discussion".
- ↑ "Rotary Club Morimondo Abbazia".
- ↑ "L'Orma, anno XL, N.1, Marzo 2022" (PDF).
- ↑ "Order of the Holy Sepulchre of Jerusalem".
- ↑ "Sacred Military Constantinian Order of Saint George (Spain)".
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