共查询到20条相似文献,搜索用时 22 毫秒
1.
《International journal of mass spectrometry and ion processes》1996,152(1):61-68
Gaseous mixtures of phosphine and germane have been investigated by ion trap mass spectrometry. Reaction pathways together with rate constants of the main reactions are reported. The mechanisms of ion/molecule reactions have been elucidated by single and multiple isolation steps. The GeHn+ (n = 1–3) ions react with phosphine to give GePHn+ (n = 2–4) ions. The GePH4+ ion further reacts with GeH4 to yield Ge2PH6+. The GePHn+ (n = 2–4) mixed ionic family also originates from the P+ phosphine primary ion, as well as from the P2Hn+ (n = 0–3) secondary ions of phosphine reacting with neutral germane and from Ge2H2+ reacting with phosphine. The main reaction pathways of the PHn+ (n = 0–2) ions with GeH4 lead to the formation of the GeH2+ and GeH3+ ionic species. Protonation of phosphine from different ionic precursors is a very common process and yields the stable phosphonium ion, PH4+. Trends in total abundances of secondary GePHn+ (n = 2–4) ions as function of reaction time for different PH3/GeH4 pressure ratios show that excess of germane slightly affects the nucleation of mixed Ge-P ions. 相似文献
2.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1993,49(9):1213-1220
Gas phase ion—molecule reactions occurring in GeH4/SiH4 systems under different partial pressures and their mechanisms have been investigated by ion trap mass spectrometry (ITMS). SiH+n (n=0–3) and GeH+n (n = 0–3) are the main ionic species at zero reaction time when the GeH4: SiH4 ratio is in the range 1:1 to 1:12. Self-condensation sequences are observed at increasing reaction times. Moreover, formation of ions containing GeSi bonds, such as GeSiH+n (in = 2–5) and GeSi2H+n (n = 4, 5), occurs by reactions of Si2H+n (n = 2–5) and Si3H+n (n = 4, 5) with GeH4. At longer reaction times, further substitution of silicon with germanium in GeSiH+n (n = 2–5) ions has been observed, to give Ge2H+n (n = 2–5). 相似文献
3.
I. S. Ignat’ev T. A. Kochina D. V. Vrazhnov 《Russian Journal of General Chemistry》2007,77(4):575-580
The potential energy surfaces of the (CH3)nH3?n M+ ions, where n = 1, 2; M = Si, Ge, were scanned using the B3LYP method with 6–31G* and aug-cc-pVDZ basis sets. The major attention was given to isomeric species having the form of complexes of the HM+ and CH3M+ ions with hydrogen, methane, and ethane molecules. These species were characterized previously neither by experimental nor by theoretical methods. It was found that these species become more stable in going from Si to Ge; the complex [CH3Ge+CH4] is the second isomer in the energy after (CH3)2HGe+. However, the heights of the activation barriers to formation of these complexes from the most stable isomer, though decreasing in going from Si to Ge, remain relatively high and, what is particularly important, somewhat exceed the activation barrier to formation of the complex [H3Ge+·C2H4]. 相似文献
4.
《Journal of organometallic chemistry》1986,303(3):337-341
Calculations have been made, using the MNDO-UHF SCF method, of molecular and electronic structures of a range of neutral organogermanes and of the corresponding cation radicals. The cation radical (GeMe4)+ is calculated to have D2d symmetry as an isolated ion, while (Ge2Me6)+ is a σ radical in which the SOMO is strongly localised in the GeGe bond. The cation radicals (Me3Ge)2O+ and (Me3Ge)2NH+ are n-π radicals, while (Me3Ge)2CH2+ dissociates to Me3Ge+ and Me3GeCH2•, which is planar at the radical centre. Both (Me3Ge)2O2 and (Me3Ge)2S2+ have trans-planar skeletons. 相似文献
5.
Michèle Decouzon Jean-Fraçois Gal Jérôme Gayraud Pierre-Charles Maria Gian-Angelo Vaglio Paolo Volpe 《Journal of the American Society for Mass Spectrometry》1993,4(1):54-57
An accurate gas-phase acidity for germane (enthalpy scale, equivalent to the proton affinity of GeH3 ?), ΔH acid o(GeH4) = 1502.0 ± 5.1 kJ mol?1, is obtained by constructing a consistent acidity ladder between GeH4, and H2S by using Fourier transform-ion cyclotron resonance spectrometry, and 0 and 298.15 K values for the first bond dissociation energy of GeH4 are proposed: D0 o(H3Ge-H) = 352 ± 9 kJ mol?1; D o(H3Ge-H) = 358 ± 9 kJ mol?1, respectively. These results are compared with experimental and theoretical data reported in the literature. Methylgermane was found to be a weaker acid than germane by approximately 35 kJ mol?1: ΔH acid o = 1536.6 kJ mol?1. 相似文献
6.
《Journal of organometallic chemistry》1986,299(1):29-40
The hydrogenation of (CF3)nGeX4-n (X = halogen, n = 1–3) with NaBH4 in an acidic medium has been investigated. Deuteration with NaBD4 and D3PO4 gave the partially deuterated species CF3GeHnD3-n and (CF3)2GeHnD2-n in reasonable isotopic purity. The (CF3)2GeHBr was isolated and converted into the halides (CF3)2GeHX (X = F, Cl, I) by treatment with AgX or HX. Insertion of CF2 into a GeH bond has been observed, and (CF3)(CF2H)GeH2 has been characterized. Direct alkylation of GeH bonds was brought about by reaction with a mixture of RI and R′2Zn (R, R′= CH3, C2H5), and the methyl(trif]uoromethyl)germanes CF3GeH2(CH3), CF3GeH(CH3)2 and (CF3)2GeH(CH3) were isolated. For R = CD3, R′ = CH3 the product distribution can be accounted in terms of two competing mechanisms. 相似文献
7.
E. Weger K. Levsen I. Ruppert P. C. Burgers J. K. Terlouw 《Journal of mass spectrometry : JMS》1983,18(8):327-330
Collisional activation spectra were used to characterize isomeric ion structures for [CH5P]+˙ and [C2H7P]+˙ radical cations and [C2H6P]+ even-electron ions. Apart from ionized methylphosphane, [CH3PH2]+˙, ions of structure [CH2PH3]+˙ appear to be stable in the gas phase. Among the isomeric [C2H7P]+˙ ions stable ion structures [CH2PH2CH3]+˙ and [CH2CH2PH3]+˙/[CH3CHPH3]+˙ are proposed as being generated by appropriate dissociative ionization reactions of alkyl phosphanes. At least three isomeric [C2H6]+ ions appear to exist, of which \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} - \mathop {\rm P}\limits^{\rm + } {\rm H = CH}_{\rm 2} $\end{document} could be identified positively. 相似文献
8.
Paola Antoniotti Lorenza Operti Roberto Rabezzana Francesca Turco Gian Angelo Vaglio Felice Grandinetti 《Journal of mass spectrometry : JMS》2009,44(5):725-734
The gas phase ion chemistry of silane/hydrogen sulfide and germane/hydrogen sulfide mixtures was studied by ion trap mass spectrometry (ITMS), in both positive and negative ionization mode. In positive ionization, formation of X/S (X = Si, Ge) mixed ions mainly takes place via reactions of silane or germane ions with H2S, through condensation followed by dehydrogenation. This is particularly evident in the system with silane. On the other side, reactions of HnS2+ ions with XH4 (X = Si, Ge) invariably lead to formation of a single X? S bond. In negative ionization, a more limited number of mixed ion species is detected, but their overall abundance reaches appreciable values, especially in the SiH4/H2S system. Present results clearly indicate that ion processes play an important role in formation and growth of clusters eventually leading to deposition of amorphous solids in chemical vapor deposition (CVD) processes. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
9.
《Mendeleev Communications》2022,32(1):22-24
A series of novel arylgermanium hydrides ArnGeH4–n (n = 1–3) and diaryl(chloro)germanium hydrides Ar2Ge(Cl)H were synthesized and characterized. Systematic preparation and purification were achieved via the lithium chloride–triflic acid and the optimized Grignard route. Arylgermanium hydrides ArnGeH4–n (Ar = 2,5-Me2C6H3, n = 1–3) were characterized by 1H and 73Ge NMR spectroscopy and single crystal X-ray diffractometry. 相似文献
10.
V. N. Smirnov 《Kinetics and Catalysis》2007,48(5):615-619
Rate constants for the two stages of germane dissociation (GeH4 → GeH2 + H2(I) and GeH2 → Ge + H2(II) have been derived from the studies of the chemiluminescence kinetics during germane dissociation in the presence of nitrous oxide behind shock waves at 1060–1300 K and the full density equal to ~10?5 mol/cm3. Analysis in terms of the RRKM model gave the following expressions for the rate constants of these reactions in the high and low pressure limits: k 1, ∞ = 2.0 × 1014exp(?208.0/RT) s?1; k 1, 0 = 1.7 × 1018(1000/T)3.85exp(?208.0/RT) cm3/(mol s); and k 2, 0 = 2.8 × 1015(1000/T)1.32exp(?135.0/RT) cm3/(mol s). The results, in combination with the available enthalpies of formation of radical GeH2, show that the back reaction for stage (I) has an energy barrier of about 66 kJ/mol. 相似文献
11.
C. M. Holznagel R. Bakhtiar D. B. Jacobson 《Journal of the American Society for Mass Spectrometry》1991,2(4):278-291
Specific ion/molecule reactions are demonstrated that distinguish the structures of the following isomeric organosilylenium ions: Si(CH3) 3 + and SiH(CH3)(C2H5)+; Si(CH3)2(C2H5)+ and SiH(C2H5) 2 + ; and Si(CH3)2(i?C3H7)+, Si(CH3)2(n?C3H7)+, Si(CH3)(C2H5) 2 + , and Si(CH3)3(π?C2H4)+. Both methanol and isotopically labeled ethene yield structure-specific reactions with these ions. Methanol reacts with alkylsilylenium ions by competitive elimination of a corresponding alkane or dehydrogenation and yields a methoxysilylenium ion. Isotopically labeled ethene reacts specifically with alkylsilylenium ions containing a two-carbon or larger alkyl substituent by displacement of the corresponding olefin and yields an ethylsilylenium ion. Methanol reactions were found to be efficient for all systems, whereas isotopically labeled ethene reaction efficiencies were quite variable, with dialkylsilylenium ions reacting rapidly and trialkylsilylenium ions reacting much more slowly. Mechanisms for these reactions and differences in the kinetics are discussed. 相似文献
12.
Viet Q. Nguyen X. G. Chen Alfred L. Yergey 《Journal of the American Society for Mass Spectrometry》1997,8(11):1175-1179
Hydration of alkylammonium ions under nonanalytical electrospray ionization conditions has been found to yield cluster ions with more than 20 water molecules associated with the central ion. These cluster ion species are taken to be an approximation of the conditions in liquid water. Many of the alkylammonium cation mass spectra exhibit water cluster numbers that appear to be particularly favorable, i.e., “magic number clusters” (MNC). We have found MNC in hydrates of mono- and tetra-alkyl ammonium ions, NH3(C m H2m+1)+(H2O) n , m=1–8 and N(C m H2m+1) 4 + (H2O) n , m=2–8. In contrast, NH2(CH3) 2 + (H2O) n , NH(CH3) 3 + (H2O) n1 and N(CH3) 4 + (H2O) n do not exhibit any MNC. We conjecture that the structures of these magic number clusters correspond to exohedral structures in which the ion is situated on the surface of the water cage in contrast to the widely accepted caged ion structures of H3O+(H2O) n and NH 4 + (H2O) n . 相似文献
13.
Teng W Allis DG Ruhlandt-Senge K 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(4):1309-1319
The preparation of a series of crown ether ligated alkali metal (M=K, Rb, Cs) germyl derivatives M(crown ether)nGeH3 through the hydrolysis of the respective tris(trimethylsilyl)germanides is reported. Depending on the alkali metal and the crown ether diameter, the hydrides display either contact molecules or separated ions in the solid state, providing a unique structural insight into the geometry of the obscure GeH3? ion. Germyl derivatives displaying M? Ge bonds in the solid state are of the general formula [M([18]crown‐6)(thf)GeH3] with M=K ( 1 ) and M=Rb ( 4 ). The compounds display an unexpected geometry with two of the GeH3 hydrogen atoms closely approaching the metal center, resulting in a partially inverted structure. Interestingly, the lone pair at germanium is not pointed towards the alkali metal, rather two of the three hydrides are approaching the alkali metal center to display M? H interactions. Separated ions display alkali metal cations bound to two crown ethers in a sandwich‐type arrangement and non‐coordinated GeH3? ions to afford complexes of the type [M(crown ether)2][GeH3] with M=K, crown ether=[15]crown‐5 ( 2 ); M=K, crown ether=[12]crown‐4 ( 3 ); and M=Cs, crown ether=[18]crown‐6 ( 5 ). The highly reactive germyl derivatives were characterized by using X‐ray crystallography, 1H and 13C NMR, and IR spectroscopy. Density functional theory (DFT) and second‐order Møller–Plesset perturbation theory (MP2) calculations were performed to analyze the geometry of the GeH3? ion in the contact molecules 1 and 4 . 相似文献
14.
Arthur J. LaPlante Sean A. Peebles Charles J. Wurrey 《Journal of Molecular Structure》2011,985(1):5-13
The FT-microwave spectrum of n-butylgermane, CH3CH2CH2CH2GeH3 has been investigated from 4000 to 18,000 MHz and the microwave spectra have been observed for all of the five naturally occurring germanium isotopologues for the anti-anti (aa) conformer. The dipole moment for the 74Ge containing species has been measured, giving a total dipole moment of 0.881 (26) D. In addition, the vibrational spectrum of n-butylgermane is described. Modestly complete assignments are made for the aa conformer. The relative stabilities of the five conformers are calculated, and the anti-anti (aa) conformer is found to be the most stable in all calculations done. This conclusion is confirmed by the infrared and Raman spectrum of the annealed crystal. The dipole moments of all conformers are calculated to be approximately equal and less than 1 D, ranging from approximately 0.8 to 0.9 D. 相似文献
15.
CASSCF–MRMP2 calculations have been carried out to analyze the reactions of the methyl fluoride molecule with the atomic ions Ge+, As+, Se+ and Sb+. For these interactions, potential energy curves for the low‐lying electronic states were calculated for different approaching modes of the fragments. Particularly, those channels leading to C? H and C? F oxidative addition products, H2FC? M? H+ and H3C? M? F+, respectively were explored, as well as the paths which evolve to the abstraction (M? F++CH3) and the elimination (CH2M++HF) asymptotes. For the reaction Ge++CH3F the only favorable channel leads to fluorine abstraction by the ion. As+ and Sb+ can react with CH3F along pathways yielding stable addition products. However, a viable path joining the oxidative addition product H3C? M? F+ with the elimination asymptote CH2M++HF was found for the reaction of the fluorocarbon compound with As+. No favorable channels were detected for the interaction of fluoromethane with Se+. The results discussed herein allow rationalizing some of the experimental data found for these interactions through gas‐phase mass spectrometry. 相似文献
16.
The reaction of PHn+ ions (n = 0–3) were examined with a number of neutrals using ion cyclotron resonance techniques. The reactions examined have significance for the distribution of phosphorus in interstellar molecules. The results indicate that interstellar molecules containing the PO bond are likely to be more abundant than those containing the PH bond. 相似文献
17.
Cross section measurements for the proton transfer reactions of NH+4, CH3NH+3, and PH+4 with Ca(g) have been obtained over a range of low ion kinetic energies. For all reactions studied the cross sections drop sharply with increase in ion kinetic energy, indicating exothermic behavior. The results show that Ca(g) is an unusually strong base with a proton affinity in excess of 9.2 eV. Cross sections for the PH+4Ca reaction are an order to magnitude higher than those for the NH+4Ca reaction for ion energies between one and three eV. This effect is not explained by simple theories of ion-induced dipole interactions. It is suggested that the enhanced rate of the PH+4Ca reaction may be due to d-orbital participation. 相似文献
18.
Paola Antoniotti Lorenza Operti Roberto Rabezzana Francesca Turco Cristina Zanzottera Maria Giordani Felice Grandinetti 《Journal of mass spectrometry : JMS》2009,44(9):1348-1358
The gas‐phase reaction of CH3+ with NF3 was investigated by ion trap mass spectrometry (ITMS). The observed products include NF2+ and CH2F+. Under the same experimental conditions, SiH3+ reacts with NF3 and forms up to six ionic products, namely (in order of decreasing efficiency) NF2+, SiH2F+, SiHF2+, SiF+, SiHF+, and NHF+. The GeH3+ cation is instead totally unreactive toward NF3. The different reactivity of XH3+ (X = C, Si, Ge) toward NF3 has been rationalized by ab initio calculations performed at the MP2 and coupled cluster level of theory. In the reaction of both CH3+ and SiH3+, the kinetically relevant intermediate is the fluorine‐coordinated isomer H3X‐F‐NF2+ (X = C, Si). This species forms from the exoergic attack of XH3+ to one of the F atoms of NF3 and undergoes dissociation and isomerization processes which eventually result in the experimentally observed products. The nitrogen‐coordinated isomers H3X‐NF3+ (X = C, Si) were located as minimum‐energy structures but do not play an active role in the reaction mechanism. The inertness of GeH3+ toward NF3 is also explained by the endoergic character of the dissociation processes involving the H3Ge‐F‐NF2+ isomer. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
19.
The behaviour in aqueous solution of some aminocarboxylates of the type NH2(CH2)nS(CH2)m-1COO? (abbreviated as n,m-NSO; n and m = 2 or 3) in equilibria with H+, Cu2+ and Ni2+ ions has been investigated potentiometrically and calorimetrically at 25° C in a 0.5 M KNO3 medium.The protonation of the amino function and especially the carboxylate function is attended by strong desolvation effects, which are characterized by low exothermic enthalpies and strongly positive entropies of protonation.In [Cu(n,m-NSO)]+ and [Ni(n,m-NSO)]+ the aminocarboxylates act as tridentate ligands, forming complexes with a strong hard—hard character. The biligand species [Ni(n,m-NSO)2] behave as six-coordinated complexes whereas in [Cu(n,m-NSO)2] the second ligand is bound only through the N and S donor, forming a five-coordinated species.Finally, the n,m-NSO ligands also form protonated species with the Cu2+ ion. 相似文献
20.
《Tetrahedron》1986,42(22):6225-6234
Ab initio molecular orbital calculations on the distonic radical cations CH2(CH2)nN+H3 and their conventional isomers CH3(CH2)nNH2+ (n = 0,1, 2 and 3) indicate a preference in each case for the distonic isomer. The energy difference appears to converge with increasing n towards a limit which is close to the energy difference between the component systems CH3·H2+CH3+NH3 (representing the distonic isomer) and CH3CH3+CH3NH2+ (representing the conventional isomer). The generality of this result is assessed by using results for the component systems CH3·Y+CH3X+H and CH3YH+CH3X+. (or CH3YH+. + CH3X) to predict the relative energies of the distonic ions ·Y(CH2)nX+H and their conventional isomers HY(CH2)nX+. (X = NH2, OH, F, PH2, SH, Cl; Y = CH2, NH, O) and testing the predictions through explicit calculations for systems with n = 0,1 and 2. Although the predictions based on component systems are often close to the results of direct calculations, there are substantial discrepancies in a number of cases; the reasons for such discrepancies are discussed. Caution must be exercised in applying this and related predictive schemes. For the systems examined in the present study, the conventional radical cation is predicted in most cases to lie lower in energy than its distonic isomer. It is found that the more important factors contributing to a preference for distonic over conventional radical cations are the presence in the system of a group(X) with high proton affinity and the absence of a group (X, Y or perturbed (C—C) with low ionization energy. 相似文献