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1.
The charge stripping mass spectra of [C2H5O]+ ions permit the clear identification of four distinct species: \documentclass{article}\pagestyle{empty}\begin{document}${\rm CH}_{\rm 3} - {\rm O - }\mathop {\rm C}\limits^{\rm + } {\rm H}_{\rm 2}$\end{document}, \documentclass{article}\pagestyle{empty}\begin{document}${\rm CH}_{\rm 3} - \mathop {\rm C}\limits^{\rm + } {\rm H - OH}$\end{document}, and \documentclass{article}\pagestyle{empty}\begin{document}${\rm CH}_{\rm 2} = {\rm CH - }\mathop {\rm O}\limits^{\rm + } {\rm H}_{\rm 2}$\end{document}. The latter, the vinyloxonium ion, has not been identified before. It is generated from ionized n-butanol and 1,3-propanediol. Its heat of formation is estimated to be 623±12 kJ mol?1. The charge stripping method is more sensitive to these ion structures than conventional collisional activation, which focuses attention on singly charged fragment ions.  相似文献   

2.
Ion cyclotron resonance spectrometry and deuterium labeling have been used to determine that nondecomposing \documentclass{article}\pagestyle{empty}\begin{document}${\rm (CH}_{\rm 3} {\rm)}_{\rm 2} \mathop {\rm N}\limits^{\rm + } {\rm = CH}_{\rm 2}$\end{document} ions do not isomerize to \documentclass{article}\pagestyle{empty}\begin{document}${\rm CH}_{\rm 3} {\rm CH = }\mathop {\rm N}\limits^{\rm + } {\rm HCH}_{\rm 3}$\end{document}.  相似文献   

3.
Several \documentclass{article}\pagestyle{empty}\begin{document}$ \left[{{\rm C}_{{\rm 4}} {\rm H}_{{\rm\ 8}} } \right]_{}^{_.^ + } $\end{document} ion isomers yield characteristic and distinguishable collisional activation spectra: \documentclass{article}\pagestyle{empty}\begin{document}$ \left[{{\rm 1-butene} } \right]_{}^{_.^ + } $\end{document} and/or \documentclass{article}\pagestyle{empty}\begin{document}$ \left[{{\rm 2-butene} } \right]_{}^{_.^ + } $\end{document} (a-b), \documentclass{article}\pagestyle{empty}\begin{document}$ \left[{{\rm isobutene} } \right]_{}^{_.^ + } $\end{document} (c) and [cyclobutane]+ (e), while the collisional activation spectrum of \documentclass{article}\pagestyle{empty}\begin{document}$ \left[{{\rm methylcyclopropane} } \right]_{}^{_.^ + } $\end{document} (d) could also arise from a combination of a-b and c. Although ready isomerization may occur for \documentclass{article}\pagestyle{empty}\begin{document}$ \left[{{\rm C}_{{\rm 4}} {\rm H}_{{\rm 8}} } \right]_{}^{_.^ + } $\end{document} ions of higher internal energy, such as d or ea, b, and/or c, the isomeric product ions identified from many precursors are consistent with previously postulated rearrangement mechanisms. 1,4-Eliminations of HX occur in 1-alkanols and, in part, 1-buthanethiol and 1-bromobutane. The collisional activation data are consistent with a substantial proportion of 1,3-elimination in 1- and 2-chlorobutane, although 1,2-elimination may also occur in the latter, and the formation of the methylcycloprpane ion from n-butyl vinyl ether and from n-butyl formate. Surprisingly, cyclohexane yields the \documentclass{article}\pagestyle{empty}\begin{document}$ \left[{{\rm linear butene} } \right]_{}^{_.^ + } $\end{document} ions a-b, not \documentclass{article}\pagestyle{empty}\begin{document}$ \left[{{\rm cyclobutane} } \right]_{}^{_.^ + } $\end{document}, e.  相似文献   

4.
\documentclass{article}\pagestyle{empty}\begin{document}$ \left[{{\rm C}_{{\rm 10}} {\rm H}_{{\rm 14}} } \right]_{}^{_.^ + } $\end{document} ions have been generated from a number of adamantanoid compounds, both by ionization and ionization followed-by fragmentation. Metastable ion abundance ratios of competitive reactions indicate the decomposition of these ions from common structures in all cases.  相似文献   

5.
Characterization of [C4H5O]+ ions in the gas phase using their collisional activation spectra shows that the four C3H5\documentclass{article}\pagestyle{empty}\begin{document} $\mathop {\rm C}\limits^ + =\!= $\end{document}O isomers CH2?C(CH3)\documentclass{article}\pagestyle{empty}\begin{document} $\mathop {\rm C}\limits^ + =\!= $\end{document}O, CH2?CHCH2\documentclass{article}\pagestyle{empty}\begin{document} $\mathop {\rm C}\limits^ + =\!= $\end{document}O, CH3CH?CH\documentclass{article}\pagestyle{empty}\begin{document} $\mathop {\rm C}\limits^ + =\!= $\end{document}O and ?? \documentclass{article}\pagestyle{empty}\begin{document} $\mathop {\rm C}\limits^ + =\!= $\end{document}O are stable for ≥ 10?5 s. It is concluded further from the characteristic shapes for the unimolecular loss of CO from C3H5\documentclass{article}\pagestyle{empty}\begin{document} $\mathop {\rm C}\limits^ + =\!= $\end{document}O ions generated from a series of precursor molecules that the CH2?CH(CH3)\documentclass{article}\pagestyle{empty}\begin{document} $\mathop {\rm C}\limits^ + =\!= $\end{document}O- and CH2?CHCH2\documentclass{article}\pagestyle{empty}\begin{document} $\mathop {\rm C}\limits^ + =\!= $\end{document}O-type ions dissociate over different potential surfaces to yield [allyl]+ and [2-propenyl]+ [C3H5]+ product ions respectively. Cyclopropyl carbonyl-type ions lose CO with a large kinetic energy release, which points to ring opening in the transition state, whereas this loss from CH3CH?CH\documentclass{article}\pagestyle{empty}\begin{document} $\mathop {\rm C}\limits^ + =\!= $\end{document}O-type ions is proposed to occur via a rate determining 1,2-H shift to yield 2-propenyl cations.  相似文献   

6.
Hydrogen evolution reaction (HER) is the major cathodic reaction which competes \begin{document}${\rm C}\rm{O}_\rm{2}$\end{document} reduction reaction (\begin{document}${\rm C}\rm{O}_\rm{2}$\end{document} RR) on Pt electrode. Molecular level understanding on how these two reactions interact with each other and what the key factors are of \begin{document}${\rm C}\rm{O}_\rm{2}$\end{document} RR kinetics and selectivity will be of great help in optimizing electrolysers for \begin{document}${\rm C}\rm{O}_\rm{2}$\end{document} reduction. In this work, we report our results of hydrogen evolution and \begin{document}${\rm C}\rm{O}_\rm{2}$\end{document} reduction on Pt(111) and Pt film electrodes in \begin{document}${\rm C}\rm{O}_\rm{2}$\end{document} saturated acid solution by cyclic voltammetry and infrared spectroscopy. In solution with pH > 2, the major process is HER and the interfacial pH increases abruptly during HER; \begin{document}${\rm C}\rm{O}_\rm{ad}$\end{document} is the only adsorbed intermediate detected in \begin{document}${\rm C}\rm{O}_\rm{2}$\end{document} reduction by infrared spectroscopy; the rate for \begin{document}${\rm C}\rm{O}_\rm{ad}$\end{document} formation increases with the coverage of UPD-H and reaches maximum at the onset potential for HER; the decrease of \begin{document}${\rm C}\rm{O}_\rm{ad}$\end{document} formation under HER is attributed to the available limited sites and the limited residence time for the reduction intermediate (\begin{document}$\rm{H}_\rm{ad}$\end{document}), which is necessary for \begin{document}${\rm C}\rm{O}_\rm{2}$\end{document} adsorption and reduction.  相似文献   

7.
The reactions of metastable $ {\rm CH}_{\rm 2} = {\rm CHCH =}\mathop {{\rm OCH}_{\rm 3}}\limits^{\rm +} $ oxonium ions generated by alkyl radical loss from ionized allylic alkenyl methyl ethers are reported and discussed. Three main reactions occur, corresponding to expulsion of H2O, C2H4/CO and CH2O. There is also a very minor amount of C3H6 elimination. The mechanisms of these processes have been probed by 2H- and 13C-labelling experiments. Special attention is given to the influence of isotope effects on the kinetic energy release accompanying loss of formaldehyde from 2H-labelled analogues of $ {\rm CH}_{\rm 2} = {\rm CHCH =}\mathop {{\rm OCH}_{\rm 3}}\limits^{\rm + } $. Suggestions for interpreting these reactions in terms of routes involving ion–neutral complexes are put forward.  相似文献   

8.
Loss of an alkyl group X? from acetylenic alcohols HC?C? CX(OH)(CH3) and gas phase protonation of HC?C? CO? CH3 are both shown to yield stable HC?C? \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm C}\limits^{\rm + } $\end{document}(OH)(CH3) ions. Ions of this structure are unique among all other [C4H5O]+ isomers by having m/z 43 [C2H3O]+ as base peak in both the metastable ion and collisional activation spectra. It is concluded that the composite metastable peak for formation of m/z 43 corresponds to two distinct reaction profiles which lead to the same product ion, CH3\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm C}\limits^{\rm + } $\end{document}?O, and neutral, HC?CH. It is further shown that the [C4H5O]+ ions from related alcohols (like HC?C? CH(OH)(CH3)) which have an α-H atom available for isomerization into energy rich allenyl type molecular ions, consist of a second stable structure, H2C?\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm C}\limits^{\rm + } $\end{document}? C(OH)?CH2.  相似文献   

9.
The development of \begin{document}$\rm{Bi}_2$\end{document}W\begin{document}$\rm{O}_6$\end{document}-based materials has become one of research hotspots due to the increasing demands on high-efficient photocatalyst responding to visible light. In this work, the effect of high energy radiation (\begin{document}$\gamma$\end{document}-ray) on the structure and the photocatalytic activity of \begin{document}$\rm{Bi}_2$\end{document}W\begin{document}$\rm{O}_6$\end{document} nanocrystals was first studied. No morphological change of \begin{document}$\rm{Bi}_2$\end{document}W\begin{document}$\rm{O}_6$\end{document} nanocrystals was observed by SEM under \begin{document}$\gamma$\end{document}-ray radiation. However, the XRD spectra of the irradiated \begin{document}$\rm{Bi}_2$\end{document}W\begin{document}$\rm{O}_6$\end{document} nanocrystals showed the characteristic 2\begin{document}$\theta$\end{document} of (113) plane shifts slightly from 28.37\begin{document}$^{\rm{o}}$\end{document} to 28.45\begin{document}$^{\rm{o}}$\end{document} with the increase of the absorbed dose, confirming the change in the crystal structure of \begin{document}$\rm{Bi}_2$\end{document}W\begin{document}$\rm{O}_6$\end{document}. The XPS results proved the crystal structure change was originated from the generation of oxygen vacancy defects under high-dose radiation. The photocatalytic activity of \begin{document}$\rm{Bi}_2$\end{document}W\begin{document}$\rm{O}_6$\end{document} on the decomposition of methylene blue (MB) in water under visible light increases gradually with the increase of absorbed dose. Moreover, the improved photocatalytic performance of the irradiated \begin{document}$\rm{Bi}_2$\end{document}W\begin{document}$\rm{O}_6$\end{document} nanocrystals remained after three cycles of photocatalysis, indicating a good stability of the created oxygen vacancy defects. This work gives a new simple way to improve photocatalytic performance of \begin{document}$\rm{Bi}_2$\end{document}W\begin{document}$\rm{O}_6$\end{document} through creating oxygen vacancy defects in the crystal structure by \begin{document}$\gamma$\end{document}-ray radiation.  相似文献   

10.
Five new monomers of transition metal complexes containing a styryl group, trans-\documentclass{article}\pagestyle{empty}\begin{document}$ {\rm Pd}({\rm PBu}_{\rm 3})_2 \rlap{--} ({\rm C}_6 {\rm H}_4 {\rm CH} \hbox{=\hskip-2pt=} {\rm CH}_2 ){\rm X\ X \hbox{=\hskip-2pt=} Cl(Ia),\ X \hbox{=\hskip-2pt=} Br(Ib)},\ {\rm X \hbox{=\hskip-2pt=} CN(Ic),\ X \hbox{=\hskip-2pt=} Ph(Id)} $\end{document} and trans-\documentclass{article}\pagestyle{empty}\begin{document}${\rm Pt(PBu}_{\rm 3} {\rm )}_{\rm 2} \rlap{--} ({\rm C}_{\rm 6} {\rm H}_{\rm 4} {\rm CH} \hbox{=\hskip-2pt=} {\rm CH}_2 ){\rm Cl}({\rm II})$\end{document}, were synthesized. The monomers were readily homopolymerized in benzene with the use of AIBN or BBu3–oxygen as the initiator. Copolymerization of Ia with styrene was carried out by using AIBN. From the Cl content of the copolymers by analysis, monomer reactivity ratios and Qe values were obtained as follows: r1 = 1.49, r2 = 0.45; Q2 = 0.41, e2 = ?1.4 (M1 = styrene, M2 = Ia). Based on the above data, the σ-bonded palladium moiety at para position of styrene acts as a strongly electron-donating group to the phenyl ring. This is also supported by the olefinic β-carbon chemical shift of 13C NMR for Ia.  相似文献   

11.
Ab initio molecular orbital calculations with split-valence plus polarization basis sets and incorporating electron correlation and zero-point energy corrections have been used to examine possible equilibrium structures on the [C2H7N]+˙ surface. In addition to the radical cations of ethylamine and dimethylamine, three other isomers were found which have comparable energy, but which have no stable neutral counterparts. These are \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm C}\limits^{\rm .} {\rm H}_{\rm 2} {\rm CH}_{\rm 2} \mathop {\rm N}\limits^{\rm + } {\rm H}_{\rm 3} $\end{document}, \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} \mathop {\rm C}\limits^{\rm .} {\rm H}\mathop {\rm N}\limits^{\rm + } {\rm H}_{\rm 3} $\end{document}and\documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} \mathop {\rm N}\limits^{\rm + } {\rm H}_{\rm 2} \mathop {\rm C}\limits^. {\rm H}_{\rm 2} {\rm }, $\end{document} with calculated energies relative to the ethylamine radical cation of ?33, ?28 and 4 kJ mol?1, respectively. Substantial barriers for rearrangement among the various isomers and significant binding energies with respect to possible fragmentation products are found. The predictions for \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm C}\limits^. {\rm H}_{\rm 2} {\rm CH}_{\rm 2} \mathop {\rm N}\limits^ + {\rm H}_{\rm 3} $\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} \mathop {\rm C}\limits^{\rm .} {\rm H}\mathop {\rm N}\limits^{\rm + } {\rm H}_{\rm 3}$\end{document} are consistent with their recent observation in the gas phase. The remaining isomer, \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} \mathop {\rm N}\limits^{\rm + } {\rm H}_{\rm 2} \mathop {\rm C}\limits^{\rm .} {\rm H}_{\rm 2} {\rm },$\end{document}is also predicted to be experimentally observable.  相似文献   

12.
Evidence is presented for the gas phase generation of at least eight stable isomeric [C2H7O2]+ ions. These include energy-rich protonated peroxides (ions \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} {\rm CH}_2 {\rm O}\mathop {\rm O}\limits^{\rm + } {\rm H}_{\rm 2} $\end{document} (e), \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} {\rm CH}_{\rm 2} \mathop {\rm O}\limits^{\rm + } {\rm (H)OH} $\end{document} (f) and \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} {\rm O}\mathop {\rm O}\limits^{\rm + } {\rm (H)CH}_{\rm 3} {\rm (g)),} $\end{document} (g)), proton-bound dimers (ions \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} {\rm CH = O} \cdot \cdot \cdot \mathop {\rm H}\limits^{\rm 3} \cdot \cdot \cdot {\rm OH}_{\rm 2} $\end{document} (h) and \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH2 = O} \cdot \cdot \cdot \mathop {\rm H}\limits^{\rm + } \cdot \cdot \cdot {\rm HOCH}_{\rm 3} $\end{document} (i)) and hydroxy-protonated species (ions \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 2} {\rm (OH)CH}_{\rm 2} \mathop {\rm O}\limits^{\rm + } {\rm H}_{\rm 2} (a), $\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} {\rm CH(OH)}\mathop {\rm O}\limits^{\rm + } {\rm H}_{\rm 2} $\end{document} (b) and \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} {\rm OCH}_{\rm 2} \mathop {\rm O}\limits^{\rm + } {\rm H}_{\rm 2} $\end{document} (c)). The important points of the present study are (i) that these ions are prevented by high barriers from facile interconversion and (ii) that both electron-impact- and proton-induced gas phase decompositions seem to proceed via multistep reactions, some of which eventually result in the formation of proton-bound dimers.  相似文献   

13.
The γ-distonic radical ions R$ \mathop {\rm O}\limits^ + $CHR′CH2?HR″ and their molecular ion counterparts R$ \mathop {\rm O}\limits^{{\rm + } \cdot } $CHR′CH2CH2R″ have been studied by isotopic labelling and collision-induced dissociation, applying a potential to the collision cell in order to separate activated from spontaneous decompositions. The stability of CH3$ \mathop {\rm O}\limits^ + $HCH(CH3)CH2?HCH3, C2H5$ \mathop {\rm O}\limits^ + $HCH(CH3)CH2?HCH3, CH3$ \mathop {\rm O}\limits^ + $HCH(CH3)CH2?H2, CH3$ \mathop {\rm O}\limits^ + $HCH2CH2?HCH3 and C2H5$ \mathop {\rm O}\limits^ + $HCH2CH2?HCH3, has been demonstrated and their characteristic decomposition, alcohol loss, identified. For all these γ-distonic ions, the 1,4-H abstraction leading to their molecular ion counterpart exhibits a primary isotope effect.  相似文献   

14.
The structures of copolymers of aziridines with cyclic imides were determined by means of infrared spectrometry, paper electrophoresis of the hydrolyzate, and NMR spectrometry. The structure of the repeating unit in the copolymer of ethylenimine with succinimide was \documentclass{article}\pagestyle{empty}\begin{document}$\rlap{--} ({\rm CH}_2 {\rm CH}_2 {\rm NHCOCH}_2 {\rm CH}_2 {\rm CONH}\rlap{--} ) $\end{document}. The endgroups of the copolymer were N-acylethylenimine ring, N-substituted succinimide ring, and primary amide group. The copolymer of ethylenimine with N-ethylsuccinimide had the repeating unit of \documentclass{article}\pagestyle{empty}\begin{document}$ \rlap{--} [{\rm CH}_2 {\rm CH}_2 {\rm NHCOCH}_2 {\rm CH}_2 {\rm CON}({\rm C}_2 {\rm H}_5 )\rlap{--} ] $\end{document} and the endgroups of N-acylethylenimine and N-substituted succinimide ring. N-Ethylethylenimine did not copolymerize with succinimide, but in the presence of water, the reaction occurred to give an amorphous polymer. This copolymer had the repeating unit \documentclass{article}\pagestyle{empty}\begin{document}$ \rlap{--} [{\rm CH}_2 {\rm CH}_2 {\rm NHCOCH}_2 {\rm CH}_2 {\rm CON}({\rm C}_2 {\rm H}_5 )\rlap{--} ] $\end{document} and the endgroups were N-substituted succinimide ring and amine group but not N-acylethylenimine ring. On the basis of this structural information, the initiation reaction was discussed.  相似文献   

15.
A comparative study of the average molecular optical anisotropy 〈γ2〉 of the polyoxyethylene chain, \documentclass{article}\pagestyle{empty}\begin{document}${\rm R} \hbox{---} {\rm O}\rlap{--} ({\rm CH}_2 {\rm CH}_2 {\rm O}\rlap{--} )_n {\rm R}$\end{document} where R = CH3, H and n is the degree of polymerization of the molecule, was carried out for the different internal rotational models considered in Part I of this series. In particular, the results obtained show that the condition of interdependence between internal rotational angles of nearest-neighboring bonds increases the average molecular optical anisotropy by about 4% (n ? 1), compared with the case of independent rotations. This increase is much weaker than in polyethylene chains, for which it is about 20% under analogous conditions.  相似文献   

16.
The photochemical interaction of triplet acetophenone /TRO/ with α-phenyl ethyl hydroperoxide /HROOH/ has been studied in CCl4 and CH3CN. In CCl4 only the \(/n\pi /^{\rlap{--} x}\) state ofTRO is active abstracting hydrogen from HROOH molecules. In CH3CN both hydrogen abstraction and homolysis of HROOH take place, that is both \(/n\pi /^{\rlap{--} x}\) and \(/\pi \pi /^{\rlap{--} x}\) states of triplet RO play active role.  相似文献   

17.
The [C4H8O] ion in the mass spectrum of 1-hepten-3-ol is shown to be \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm{CH}}_{\rm{3}} {\rm{CH}}_{\rm{2}} {\rm{C(= }}\mathop {\rm{O}}\limits^{\rm{ + }} {\rm{H}})\mathop {\rm{C}}\limits^{\rm{.}} {\rm{H}}_{\rm{2}} $\end{document} by collisional activation spectra, appearance energies and comparison of the ratios of the intensities of metastable decompositions. [C4H8O] appears to be formed by rearrangement of ionized 1-hepten-3-ol to \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm{CH}}_{\rm{3}} \mathop {\rm{C}}\limits^{\rm{.}} {\rm{HC(= }}\mathop {\rm{O}}\limits^{\rm{ + }} {\rm{H)CH}}_{\rm{2}} {\rm{CH}}_{\rm{2}} {\rm{CH}}_{\rm{2}} {\rm{CH}}_{\rm{3}} $\end{document} followed by γ-hydrogen rearrangement-β-cleavage.  相似文献   

18.
The unimolecular decompositions of two isomers of [C3H8N]+, \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} {\rm CH}_{\rm 2} {\rm CH} = \mathop {\rm N}\limits^ + {\rm H}_2 $\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} {\rm CH}_{\rm 2} \mathop {\rm N}\limits^ + {\rm H = CH}_{\rm 2} $\end{document}, are discussed in terms of the potential energy profile over which reaction may be considered to occur. The energy needed to promote slow (metastable) dissociations of either ion is found to be less than that required to cause isomerization to the other structure. This finding is supported by the observation of different decomposition pathways, different metastable peak shapes for C2H4 loss, the results of 2H labelling studies, and energy measurements on the two ions. The corresponding potential energy profile for decomposition of the oxygen analogues, \documentclass{article}\pagestyle{empty}\begin{document}${\rm CH}_{\rm 3} {\rm CH}_{\rm 2} {\rm CH =\!= }\mathop {\rm O}\limits^ + {\rm H} $\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} {\rm CH}_{\rm 2} \mathop {\rm O}\limits^ + {\rm = CH}_{\rm 2} $\end{document}, is compared and contrasted with that proposed for the [C3H8N]+ isomers. This analysis indicates that for the oxygen analogues, the energy needed to decompose either ion is very similar to that required to cause isomerization to the other structure. Consequently, dissociation of either ion is finely balanced with rearrangement to the other and similar reactions are observed. Detailed mechanisms are proposed for loss of H2O and C2H4 from each ion and it is shown that these mechanisms are consistent with 2H and 13C labelling studies, the kinetic energy release associated with each decomposition channel, the relative competition between H2O and C2H4 loss and energy measurements.  相似文献   

19.
On Chalcogenolates. 171. Reaction of N,N′-Diphenyl Formamidine with Carbon Disulfide. 4. Esters of N,N′-Diphenyl-N-Formimidoyl Dithiocarbamic Acid Potassium N,N′-diphenyl N-formimidoyl dithiocarbamate reacts with alkyl halides to yield the corresponding esters \documentclass{article}\pagestyle{empty}\begin{document}${\rm C}_6 {\rm H}_5 {\rm N} = CH - {\rm N}({\rm C}_6 {\rm H}_5) - {\rm CR} - {\rm SR, where R = CH}_3,{\rm C}_2 {\rm H}_5,{\rm CH}_2 - {\rm C}_6 {\rm H}_5,$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}${\rm and (C}_6 {\rm H}_5 {\rm N} = CH - {\rm N}({\rm C}_6 {\rm H}_5) - {\rm CS)}_{\rm 2} = {\rm CH}_2 .$\end{document} The phenyl ester (R = C6H5) has been synthesized by reaction of N,N′-diphenyl formamidine with the phenyl ester of chlorodithioformic acid. The prepared compounds have been characterized by means of electron absorption, infrared, nuclear magnetic resonance (1H and 13C), and mass spectra.  相似文献   

20.
Linear polyacroleins prepared by anionic polymerization give the structural repeat units of the types \documentclass{article}\pagestyle{empty}\begin{document}$ \rlap{--}[{\rm CH}\left( {{\rm CHO}} \right)\hbox{--} {\rm CH}_{\rm 2} {\rm \rlap{--} ], \rlap{--} [CH}_{\rm 2} \hbox{--} {\rm CH}\left( {{\rm CHO}} \right)\rlap{--} ], $\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$ \rlap{--} [{\rm CH}\left( {{\rm CH}\hbox {\rm CH}_2 } \right)\hbox{\rm O\rlap{--} ]} $\end{document} without any cyclization. Analysis of these polymers by several methods reveal the nature and amount of each structural species, and an estimation of their distribution along the polymeric chain.  相似文献   

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