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Dovas A. Saulys Cornelis E. C. A. Hop Donald F. Gaines 《Journal of the American Society for Mass Spectrometry》1994,5(6):537-543
Metastable ion (MI) and collision-induced dissociation (CID) mass spectra have been recorded and compared for all nine C4H12Si+. isomers. The (Me)4Si+., t-BuSiH 3 +. , s-BuSiH 3 + , and (Me)2EtSiH+. isomers have unique MI and CID mass spectra. The MI mass spectra, including the kinetic energy release values, of (Me)(i-Pr)SiH 2 +. and (Me)(n-Pr)SiH 2 +. are identical, which implies isomerization. MI data also suggest that a fraction of the n-BuSiH 3 +. ions rearrange into branched (Me)2EtSiH+. ions and a fraction of the n-BuSiH 3 +. ions rearrange into branched s-BuSiH 3 +. ions. A comparison with the isomeric C5H 12 +. pentanes reveals a crucial difference: H2 loss occurs for n-BuSiH 3 +. , i-BuSiH 3 +. , s-BuSiH 3 +. , (Me)(n-Pr)SiH 2 +. , (Me)(i-Pr)SiH 2 +. , and Et2SiH 2 +. , but not for any of the C5Hi 12 +. isomers. Generation of four- or five-membered silicon containing rings is suggested for H2 loss from the C4H12Si+. silanes. 相似文献
2.
Cornelis E. C. A. Hop Dovas A. Saulys Donald F. Gaines 《Journal of the American Society for Mass Spectrometry》1995,6(9):860-865
Two borane salts ([(Me)4N][B3H8] and Cs[B3H8]) were examined by electrospray mass spectrometry in the positive ion mode. Acetonitrile solutions provided the most informative spectra; the salts exhibited a remarkable degree of clustering under electrospray conditions, and virtually all signals corresponded to cationic cluster ions of the general formula {[cation m+] x [anion n?] y }(mx ? ny)+. In contrast, methanol solutions of these salts produced only B(OCH3) 4 ? cluster ions under otherwise identical conditions. 11B NMR analyses corroborate the identities of the methanol solution species that enter the electrospray source and the reaction product generated during the electrospray process. 相似文献
3.
Dovas A. Saulys Ilia A. Guzei 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(8):m369-m371
The asymmetric unit of the title compound, (C5H6N)2[NbCl4O(C5H5N)]Cl or (pyH)2[O=NbCl4(py)]Cl (py is pyridine), contains a discrete anionic niobium(V) complex, [O=NbCl4(py)]−, and two protonated pyridine molecules, which form medium–strong hydrogen bonds with the Cl− counter‐ion. The Nb=O distance of 1.7643 (17) Å is the longest among those in congener niobium complexes reported to date. Extensive density functional theory studies of conformations of [O=NbCl4(py)]− and structural data mining raise doubts regarding the reliability of the length of this Nb=O double bond. 相似文献
4.
Albergo S Bellwied R Bennett M Boemi D Bonner B Caines H Christie W Costa S Crawford HJ Cronqvist M Debbe R Engelage J Flores I Greiner L Hallman T Hijazi G Hoffmann G Huang HZ Humanic TJ Insolia A Jensen P Judd EG Kainz K Kaplan M Kelly S Kotov I Kunde G Lindstrom PJ Ljubicic T Llope W LoCurto G Longacre R Lynn D Madansky L Mahzeh N Milosevich Z Mitchell JM Mitchell JW Nehmeh S Nociforo C Paganis S Pandey SU Potenza R Russ DE Saulys A Schambach J Sheen J Sugarbaker E Takahashi J Tang J 《Physical review letters》2002,88(6):062301
E896 has measured Lambda production in 11.6A GeV/c Au-Au collisions over virtually the whole rapidity phase space. The midrapidity p(t) distributions have been measured for the first time at this energy and appear to indicate that the Lambda hyperons have different freeze-out conditions than protons. A comparison with the relativistic quantum molecular dynamics model shows that while there is good shape agreement at high rapidity the model predicts significantly different slopes of the m(t) spectra at midrapidity. The data, where overlap occurs, are consistent with previously reported measurements. 相似文献
5.
Rath MG Cason NM Bensinger JR Bishop JM Biswas NN Busenitz JK Etkin A Foley KJ Fortner MR Fortney LR Goo J Kenney VP Kirsch LE Kramer MA Lindenbaum SJ Longacre RS Love WA McCrory E Morris TW Piekarz H Piekarz J Platner ED Poster RA Ruchti RC Saulys AC Shephard WD Zogrofou P 《Physical review D: Particles and fields》1989,40(3):693-705
6.
Hop CE Saulys DA Gaines DF Szulejko JE McMahon TB 《Journal of mass spectrometry : JMS》2000,35(8):1003-1010
Metastable Ion (MI) and collision-induced dissociation (CID) mass spectra for all isomeric even-electron [C(4)H(12)Si - H](+) ions were recorded and compared. Deuterium labeling experiments indicated that most precursors give rise to silylium ions. Silylium ions with two or more methyl groups are found to lose C(2)H(4) after isomerization via a straightforward hydrogen transfer to the appropriate ethylsilylium ion. Similarly, all isomeric propyl- and butyl-containing silylium ions are found to lose C(2)H(4) by rearrangement preceding dissociation. In the CI source of the mass spectrometer many of the silylium ions are found to cluster with the parent neutral silane present in the source to give stable [M - H](+)+M adduct ions. The MI and CID spectra of these adduct ions were also obtained. In the MI spectra of all adducts, except i-BuSiH(3), only the starting silylium ion is observed. Under CID conditions generation of silylium ions dominates. Deuterium labeling studies show that this dissociation may be accompanied by some rearrangement, in particular for the adducts from i-BuSiH(3). High-pressure mass spectrometric clustering equilibrium measurements were also carried out to determine the enthalpies and entropies of binding of the silylium ions to the neutral silanes. These measurements yield insight into the effects of various alkyl group substitutions on the association thermochemistry in these adducts. Copyright 2000 John Wiley & Sons, Ltd. 相似文献
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Ilia A. Guzei John Roberts Dovas A. Saulys 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(3):m141-m143
The title compound, (C5H6N)[NbCl4O(C5H5N)]·C5H5N, crystallizes as discrete ions, with a very strong linear N—H?N hydrogen‐bonding interaction between the cation and the solvate pyridine molecule [N?N 2.755 (5) Å]. All chemical species occupy crystallographic twofold axes. The ligated and solvate pyridines form ABABAB stacks in the lattice. There is pseudosymmetry which emulates a centred unit cell in Amm2, but it is not supported by the diffraction pattern, which is consistent with the correct space group Pnc2. Three crystallographic software packages suggested space group Amm2 over Pnc2, while a fourth indicated Pnc2, a subgroup of Amm2. 相似文献
8.
J.R. Bensinger S.M. Jacobs L.E. Kirsch S.C. Moore P.E. Schmidt S.U. Chung K.J. Foley W.A. Love W.J. Miller T.W. Morris S. Ozaki E.D. Platner S.D. Protopopescu A.C. Saulys E.H. Willen S.J. Lindenbaum R.M. Edelstein D.R. Green D.P. Weygand 《Nuclear Physics B》1977,119(1):77-84
Using the multiparticle spectrometer facility (MPS) at BNL, we have set upper limits on the formation of a meson state in the mass range 2.99–3.14 GeV from proton-anti-proton annihilations. The upper limits are, in terms of the cross section integrated over the width, 18 MeV · μb for the final state , and 2 MeV · μb for KSKL. 相似文献
9.
Rath MG Cason NM Bensinger JR Bishop JM Biswas NN Busenitz JK Etkin A Foley KJ Fortner MR Fortney LR Goo J Goshaw AT Kenney VP Kirsch LE Kramer MA Lindenbaum SJ Longacre RS Love WA McCrory E Morris TW Piekarz H Piekarz J Platner ED Poster RA Robertson WJ Ruchti RC Saulys AC Shephard WD Zogrofou P 《Physical review letters》1988,61(7):802-805
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