Oxygen atoms ethereal

The name ether refers to any compound that has two alkyl groups linked through an oxygen atom. Ether is also used as an everyday name for diethyl ether, Et20. You might compare this use of the word ether with the common use of the word alcohol to mean ethanol. Diethyl ether is a highly flammable solvent that boils at only 35 °C. It used to be used as an anaesthetic. Tetrahydrofuran (THF) is another commonly used solvent and is a cyclic ether. 

Ethers, esters, and ketones are molecules containing carbon, hydrogen, and oxygen atoms. Ethers are colorless and have a sweet odor. Some ethers have anesthetic properties and are used medicinally. Enflurane, isoflurane, and sevoflurane are all ethers that are used clinically as anesthetics. Esters include ethyl and methyl acetate. They are used in various adhesives, gums, resins, waxes, and oils. Ketones are very effective solvents for fats, resins, and lacquers. Examples are acetone (the solvent in nail polish and nail polish remover) and methyl butyl ketone (widely used in paint thinners). 

The observation that the bulky adamantyl A -THC (13, Fig. 3) (Khanolkar et al. 2000 Palmer et al. 2002) exhibits considerable affinity and selectivity for CBi points to a greater tolerance for steric bulk in that receptor subsite. Oxygen atoms (ethers) and unsaturations (Busch-Petersen et al. 1996 Papahatjis et al. 1998)... 

Other compounds containing lone pairs of electrons readily form co-ordinate links and in each case a change in spatial configuration accompanies the bond formation. The oxygen atom in dimethyl ether, CHj—O—CHj, has two lone pairs of electrons and is able to donate one pair to, for example, boron trichloride ... 

The covalently bonded oxygen atom still has two lone pairs of electrons and can act as an electron pair donor. It rarely donates both pairs (to achieve 4-coordination) and usually only one donor bond is formed. A water molecule, for example, can donate to a proton, forming H30, and diethyl ether can donate to an acceptor such as boron trifluoride ... 

Enol ethers (Figure 2-58a) have two electron pairs on the oxygen atom in two different orbitals, one delocalized across the two carbon atoms, the other strictly localized on the oxygen atom (Figure 2-58b). Ionization ftom either of these two orbitals is associated with two quite different ionization potentials, a situation that cannot be handled by the present connection tables. 

The argtiments of Norman and his co-workers seem to give affirmative answers to the first and second of these questions, but it is doubtful if the available data further require such an answer for the third question. It can be argued that the crucial comparison made between the behaviour of benzyltrimethylammonium ion and protonated benzyl methyl ether is invalid, and that it is possible to interpret the results in terms of nitration by the nitronium ion, modified by protonation of the oxygen atom of the ether a case for the possible involvement of the nitro-nium ion in specific interaction leading to o-substitution has been made. ... 

Alkoxide ion (RO ) The oxygen atom of a metal alkoxide acts as a nucleophile to replace the halogen of an alkyl halide The product is an ether... 

As shown m Figure 16 1 however the presence of an oxygen atom permits ethers to participate m hydrogen bonds to water molecules These attractive forces cause ethers to dissolve m water to approximately the same extent as comparably constituted alco hols Alkanes cannot engage m hydrogen bonding to water... 

The strength of this bonding depends on the kind of ether Simple ethers form relatively weak complexes with metal ions but Charles J Pedersen of Du Pont discovered that cer tain polyethers form much more stable complexes with metal ions than do simple ethers Pedersen prepared a series of macrocyclic polyethers cyclic compounds contain mg four or more oxygens m a ring of 12 or more atoms He called these compounds crown ethers, because their molecular models resemble crowns Systematic nomencla ture of crown ethers is somewhat cumbersome and so Pedersen devised a shorthand description whereby the word crown is preceded by the total number of atoms m the ring and is followed by the number of oxygen atoms... 

Section 16 2 The oxygen atom m an ether or epoxide affects the shape of the mole cule in much the same way as an sp hybridized carbon of an alkane or cycloalkane... 

Although epoxides are always considered to have their oxygen atom as part of a three membered ring the prefix epoxy in the lUPAC system of nomenclature can be used to denote a cyclic ether of vanous sizes Thus... 

Multiple ether oxygen atoms can be present in the molecule. Cleavage and coupling reactions occur with direct fluorination although to a lesser extent than with ECF. This allows the direct fluorination of acid-sensitive materials, such as the formal shown below, which would not survive ECF (8). 

C-Glycosyl compounds have a carbon atom ia place of the exocycHc oxygen atom of the acetal group and, therefore, are branched cycHc ethers. An example is the naturally occurring anthroquiaone dye, carminic acid [1260-17-9] (Cl Natural Red 4). 

Another group of macrocyclic ligands that have been extensively studied are the cycHc polyethers, such as dibenzo-[18]-crown-6 (5), in which the donor atoms are ether oxygen functions separated by two or three carbon atoms. The name crown ethers has been proposed (2) for this class of compounds because of the resemblance of their molecular models to a crown. Sandwich stmctures are also known in which the metal atom is coordinated with the oxygen atoms of two crown molecules. 

Related to the crown ethers are compounds, such as hexamethyl-[14]-4,ll-diene (6), which differ by the replacement of one or more of the oxygen atoms by other kinds of donor atoms, particularly N or S. MacrocycHc amine and thioether compounds have been synthesized. Compounds having more than one kind of heteroatom in the ring are called mixed-donor macrocycles. The naturally occurring metaboUtes nonactin [6833-84-7] and monactin [7182-54-9] have both ether and ester groups incorporated in the macrocyclic stmcture. 

Crystallisable polymers have also been prepared from diphenylol compounds containing sulphur or oxygen atoms or both between the aromatic rings. Of these the polycarbonates from di-(4-hydroxyphenyl)ether and from di-(4-hydroxy-phenyl)sulphide crystallise sufficiently to form opaque products. Both materials are insoluble in the usual solvents. The diphenyl sulphide polymer also has excellent resistance to hydrolysing agents and very low water absorption. Schnell" quotes a water absorption of only 0.09% for a sample at 90% relative humidity and 250°C. Both the sulphide and ether polymers have melting ranges of about 220-240°C. The di-(4-hydroxyphenyl)sulphoxide and the di-(4-hydroxy-phenyl)sulphone yield hydrolysable polymers but whereas the polymer from the former is soluble in common solvents the latter is insoluble. 

The C(ls) and 0(ls) spectra of polyphenylene ether (PPE) before and after evaporation of chromium onto the surface are shown in Fig. 23. C(ls) spectra of neat PPE consisted of two components, near 284.6 and 286.0 eV, that were assigned to carbon atoms in the benzene and methyl groups and in the ether groups, respectively. The 0(ls) spectrum consisted of a single peak, near 533.4 eV, that was assigned to the ether oxygen atoms. After evaporation of chromium, a new peak related to formation of Cr202 was observed near 531.0 eV. 

The ethers are a group of compounds with the general formula R-O-R . The R, of course, stands for any hydrocarbon backbone, and the R also stands for any hydrocarbon backbone, but the designation R is used to indicate that the second hydrocarbon backbone may be different from the first. In other words, both the hydrocarbon backbones in the formula may be the same, but the is used to indicate that it may also be different. R-O-R as the general formula for the ethers is also correct. The fact that there are two hydrocarbon backbones on either side of an oxygen atom means that there will be two hydrocarbon names used. 

Up to 1915 it had been established that oscine was a tertiary bas containing one hydroxyl group, and that the second oxygen atom wi probably present in an etheric linkage. It was also known that on oxid ... 

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