- IR spectroscopic identification of electron attachment products of CCl4 in solid argon
-
The electron attachment products of CCl4 due to photoinduced electron transfer (using the 4.88 eV photons of a Hg lamp) from N,N-dimethylaniline and N,N,N',N'-tetramethyl-p-phenylenediamine were investigated by FTIR spectroscopy in solid argon along with extensive ab initio calculations. Two attachment products have been detected by IR spectroscopy for the first time, i.e. the anions of CCl4 and CCl3, which are characterized by the complex structures Cl2CCl ··· Cl- and ClCCl ··· Cl-, respectively.
- Richter, Andreas,Meyer, Hermann,Mueller, Thomas,Specht, Harald,Schweig, Armin
-
-
Read Online
- Competing electron transfer, proton abstraction and nucleopilic substitutions in gas-phase reactions of (radical) anions with chloro- and bromomethanes
-
The product ion distributions and rates of the gas-phase reactions of two series of (radical) anions with chloroand bromomethanes (CH3Cl, CH2Cl4, CH3Cl3, CCl4, CH3Br, CH2Br2, CHBr3 and CBr4) were determined with the use of Fourier transform ion cyclotron resonance (FT-ICR) mass spectromelry. The first series consists of anions (HO-, CH3O-, C2H5O-, C3H7O- and CH3S-), for which the corresponding neutral radicals have a relatively high electron affinity (EA > 150 kJ mol-1). The second series consists of (radical) anions (CH2S-, CH2-CHCH2-, CH2-C(CH3)CH2-, C6H4- and C6H5-), for which the corresponding neutral species have a relatively low electron affinity (EA -1). These (radical) anions react mainly with the halomethanes to afford (i) halide ions, (ii) halomethyl anions with the same number of halogen atoms as in the parent halomethane and (iii) halomethyl anions with one halogen atom less than the parent substrate. The last process involves nucleophilic attack on a halogen atom and is particularly important in the reactions with substrates containing three or four halogen atoms. The halide ions may arise by a number of different pathways, such as SN2 substitution, α-elimination, halogen attack followed by dissociation of the thus formed halomethyl anion and overall dissociative electron transfer. The SN2 process is held responsible for the formation of halide ions in the reactions with monohalomethanes, whereas α-elimination is likely to be of importance only for the reactions with trichloro- and tribromomethanes. Attack on a halogen atom followed by dissociation of the ion generated initially is likely to be important if CCl4 or CBr4 is the substrate. Electron transfer is only a dominant pathway in the reactions of the CH2S- ion with the halomethanes. The occurrence of electron transfer in the reactions of this ion with CHCl3, CCl4 and CHBr3 is evidenced by the formation of minor amounts of stable halomethane radical anions in addition to the generation of CH2SCl- or CH2SBr- ions and abundant halide ions. The interplay between the various possible reactions is discussed on the basis of thermodynamic considerations and the rates of the overall processes.
- Staneke,Groothuis,Ingemann,Nibbering
-
p. 471 - 486
(2007/10/03)
-
- STUDY OF THE ALKALINE CLEAVAGE OF THE P-C BOND IN PHOSPHINE OXIDES AND DERIVATIVES OF TRICHLOROMETHANEPHOSPHONATE
-
A study of alkaline decomposition of aromatic phosphine oxides containing p- and o-nitrobenzyl, and trichloromethyl as leaving groups, is reported.The property of the trichloromethyl group as leaving group, and the CCl3--group's further decomposition in the hydrolysis of diethyl and disodium trichloromethanephosphonates, have also been investigated.
- Aksnes, Gunnar,Gierstae, Roald,Wulvik, Erik A.
-
p. 141 - 152
(2007/10/02)
-
- Gas-Phase Reactions of O- and O2- with a Variety of Halogenated Compounds
-
The flowing afterglow technique has been applied to a comparative study, for a series of halogenated compounds, of dissociative attachment and reaction with O- and O2-.The ion product spectrum produced by reaction with O- and O2- overlaps but is more diverse than that obtained by dissociative attachment.Absolute rate constants for the O- and O2- reactions are reported.A few reactions, for which exothermic mechanisms can be written, were found to be quite inefficient.
- Streit, Gerald E.
-
p. 2321 - 2324
(2007/10/02)
-