- Halogenated closo-Dodecaborate Anions Stabilize Weakly Bound [(Me3NH)3X]2+ (X = Cl, Br) Dications in the Solid State
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Cocrystallization of [Me3NH]2[B12Y12] (Y = Cl, Br, I) with 1 equiv. of [Me3NH]X (X = Cl, Br) from acetonitrile/diethyl ether solution produced large colorless single crystals of [(Me3NH)3X][B12Y12]. Four different compounds of this type were prepared and structurally characterized. The compounds consist of weakly coordinating perhalogenated closo-dodecaborate [B12Y12]2– dianions and unprecedented weakly bound discrete [(Me3NH)3X]2+ dications. The [(Me3NH)3X]2+ dications are built up from a central halide anion and three [Me3NH]+ cations bound by N–H···X hydrogen bonds. The cations have a pyramidal structure, as determined by X-ray diffraction, which is in contrast to quantum-chemical calculations, which predict a trigonal-planar structure. While the [(Me3NH)3Cl]2+ and [(Me3NH)3Br]2+ cations were easily prepared, attempts to synthesize the corresponding [(Me3NH)3F]2+ and [(Me3NH)3I]2+ cations failed. Three further crystal structures containing the angulated [(Me3NH)2X]+ cation stabilized by [B12Cl12]2–, [B12Br12]2–, or [Me3NB12Cl11]– are reported as well.
- Bolli, Christoph,Derendorf, Janis,Jenne, Carsten,Ke?ler, Mathias
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supporting information
p. 4552 - 4558
(2017/10/25)
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- Photodegradative surfactants: p-dodecylbenzyltrimethylammonium bromide as a photodegradative emulsifier for microemulsion polymerization
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A photodegradative surfactant, p-dodecylbenzyltrimethylammonium bromide, was used as an emulsifier for micro-emulsion polymerization of methyl methacrylate in water. The resulting polymer latex was coagulated during UV irradiation. The analysis of the centrifuged solid after irradiation indicated almost perfection of both recovery of the polymer and removal of surface-active species from it. Copyright
- Itoh, Yoshihiro,Horiuchi, Satoshi,Yamamoto, Kenji
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p. 814 - 815
(2007/10/03)
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- Photodegradative surfactants: Photolysis of p-dodecylbenzyltrimethylammonium bromide in aqueous solution
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Upon UV irradiation, a benzyl-containing cationic surfactant, p-dodecylbenzyltrimethylammonium bromide, has been converted to a nonsurfactant, which can be separated from the aqueous solution by coprecipitation with CaSO4.
- Itoh, Yoshihiro,Yamamoto, Kenji,Shirai, Hirofusa
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- AMINOLYSIS OF VINYLAMMONIUM SALTS. EFFECTS OF STRUCTURE AND MEDIUM
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The kinetics of the aminolysis of a series of vinylammonium salts ZCH=CHN+R3*X- were investigated in polar solvents and in water at 25 deg C.A quantitative assessment was made of the effect of the nature of the medium and the structure of activating group Z on the rate of the investigated processes.The aminolysis rate of the salts increases with increase in the donating characteristics of the solvent on account of the greater stabilization of the transition state compared with the initial state.Increase in the accepting characteristics of the medium leads to retardation of the process as a result of increase in the electrophilic solvation of the amine in the initial state.
- Kravchenko, V. V.,Popov, A. F.,Kotenko, A. A.
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p. 1332 - 1336
(2007/10/02)
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- Stereochemistry of Photosolvolysis of (-)-1-Phenylethyltrimethylammonium Iodide in Water and in Methanol, and Nucleophile Capture Ratios during Photosolvolysis of Some Benzylammonium Salts
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The photosolvolysis of (-)-1-phenylethyltrimethylammonium iodide in water or methanol is characterised by extensive racemisation accompanied by some net configurational inversion, a result similar to that generally observed in thermal solvolysis via ion-pairs at chiral secondary centres.Recovered quaternary salt from the photolysis in water is only slightly if at all racemised, while likewise there is no observable epimerisation at nitrogen in recovered benzylammonium salts following photolysis in methanol of suitable derivatives of camphidine, trans-decahydroquinoline, and 4-phenylpiperidine.A strong preference for formation of the methyl ether rather than the alcohol is exhibited on either photochemical or thermal solvolysis of 1-p-methoxyphenylethyltrimethylammonium iodide in aqueous methanol, but nucleophile capture ratios during photosolvolysis of simple benzyltrimethylammonium salts in this mixed solvent system are much lower.
- Lillis, Veronica,Kenna, James Mc,Kenna, Jean Mc,Smith, Martin J.,Taylor, Paul S.,Williams, Ian H.
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- The Mechanism of Photolysis of Some Benzyltrimethylammonium Salts in Water and in Alcohols
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Photolysis of a range of benzyltrimethylammonium and 3,5-dimethoxybenzyltimethylammonium salts in water or methanol at 253.7 nm gave typically benzyl alcohols (or benzyl methyl ethers), toluenes, bibenzyls and isomers, and di- and tri-methylammonium salts.By detailed sensitisation and quenching experiments it was established that, in the photolysis of benzyltrimethylammonium bromide in aqueous t-butyl alcohol, benzyl t-butyl ether, benzyl alcohol, and some toluene were produced by a singlet pathway and bibenzyl by a triplet pathway.A general mechanistic scheme for all the photolyses studied is thus suggested.
- Appleton, David C.,Bull, David C.,Givens, Richard S.,Lillis, Veronica,Kenna, James Mc,et al.
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- Carboxyl terminated polydienes
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Carboxyl terminated polymers prepared by reacting a cyclic anhydride with a liquid polymeric hydroxyl terminated polymer selected from polyethers, polydienes, and copolymers of the dienes with styrene or acrylonitrile in the presence of a catalyst selected from quaternary ammonium salts and from halogen acid salts of amines. The carboxyl terminated polymers can be used as flexibilizers in epoxy resins.
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