共查询到20条相似文献,搜索用时 31 毫秒
1.
V. B. Goncharov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2006,80(2):288-290
Reactions of oxygen-containing molybdenum clusters MoxOy (x = 1–3, y = 1–9) with iron carbonyl ions Fe(CO) n + (n = 1–3) were studied by the ion cyclotron resonance technique. The reactions were found to yield mixed Fe-Mo oxo clusters MoxOyFe+ (x = 2, 3; y = 5, 6, 8, 9). 相似文献
2.
Excited Mn+ ions formed by electron ionization of Mn2(CO)10 are deexcited in superelastic electron-ion collisions. The ions are held in the trap of a Fourier transform ion cyclotron resonance spectrometer and subjected to bombardment by an electron beam of varying energy. The population of excited Mn+ ions after exposure to the beam is monitored by examining reaction of the trapped Mn+ ions with Cr(CO)6. Charge transfer to form Cr(CO) 6 + is exothermic and efficient only for excited Mn+. It is found that deexcitation is read if y observable for electrons with energies less than 2 eV. 相似文献
3.
Neil J. Coville 《Journal of organometallic chemistry》1981,218(3):337-349
The reaction between η5-C5H5M(CO)3I (M Mo, W) and isonitriles, RNC, (RNC PhCH2NC, t-BuNC and 2,6-dimethylphenylisocyanide (XyNC)) is catalysed by the dimer [η5-C5H5M(CO)3]2 (M = Mo, W) to yield η5-C5H5M(CO)3?n(RNC)nI (n = 1–3) and [η5-C5H5Mo(RNC)4]I. The complexes (η5-C5H5)2Mo2(CO)6?n(RNC)n (n = 1, RNC = MeNC, PhCH2NC, XyNC, t-BuNC; n = 2, RNC = t-BuNC) have been prepared in moderate yield from the direct reaction between [η5-C5H5Mo(CO)3]2 and RNC, and also catalyse the above reaction. A reaction pathway involving a fast non-chain radical mechanism and a slower chain radical mechanism is proposed to account for the catalysed reaction. 相似文献
4.
《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
5.
《Chemical physics letters》1986,125(2):97-100
Relative partial photoionization cross sections as a function of photon energy, over the range 20–110 eV, have been measured for the valence bands of Cr(CO)6, Mo(CO)6 and W(CO)6. All three t2g−1 bands show a very pronounced increase in intensity at photon energies (hv) corresponding to np resonant absorption (Cr(CO)6, hv = 52.5 eV, n = 3; Mo(CO)6,hv = 48 eV, n = 4; W(CO)6, hv = 44 and 53 eV, n = 5). The other valence bands show a small intensity increase at similar energies. Observation of such resonant photoemission provides an unambiguous method for assignment of nd bands in the photoelectron spectra of gas-phase molecules. 相似文献
6.
Linda Feketeová Richard A. J. O'Hair 《Rapid communications in mass spectrometry : RCM》2009,23(1):60-64
The collision‐induced dissociation (CID) and electron‐induced dissociation (EID) spectra of the [(NaCl)m(Na)n]n+ clusters of sodium chloride have been examined in a hybrid linear ion trap Fourier transform ion cyclotron resonance mass spectrometer. For singly charged cluster ions (n = 1), mass spectra for CID and EID of the precursor exhibit clear differences, which become more pronounced for the larger cluster ions. Whereas CID yields fewer product ions, EID produces all possible [(NaCl)xNa]+ product ions. In the case of doubly charged cluster ions, EID again leads to a larger variety of product ions. In addition, doubly charged product ions have been observed due to loss of neutral NaCl unit(s). For example, EID of [(NaCl)11(Na)2]2+ leads to formation of [(NaCl)10(Na)2]2+, which appears to be the smallest doubly charged cluster of sodium chloride observed experimentally to date. The most abundant product ions in EID spectra are predominantly magic number cluster ions. Finally, [(NaCl)m(Na)2]+ . radical cations, formed via capture of low‐energy electrons, fragment via the loss of [(NaCl)n(Na)] . radical neutrals. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
7.
A.E. Sánchez-Peláez M.F. Perpiñán A. Santos 《Journal of organometallic chemistry》1985,296(3):367-375
The reactions of the zerovalent carbonyl complexes Mo(CO)6 and Mo(CO)4(bipy) with a series of uninegative bidentate (X,Y)-donor ligands (X,Y = xanthates, dithiocarbamates, o-aminophenoxide, o-aminothiophenoxide, 2-picolinate and thioacetate) lead to new anionic tetracarbonyl complex anions [Mo0(X,Y)(CO)4]?. These anions, which can be isolated as their tetraphenylphosphonium salts, contain the (X,Y)-ligand as a bidentate group. In the case of (X,Y) = monothioacetate the decarbonylated species [PPh4][MoII(TA)3] is formed. The reacions of the new complexes with allyl bromide and methyl iodide are described. 相似文献
8.
《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
9.
《Journal of organometallic chemistry》1987,326(1):83-88
Mass spectra of π-(CH3)nC5H5−nRe(CO)3 MenCpReT) (n = 0–5) and t-BuCpReT were recorded, from which it was found that molecular ion (M+) fragmentation for MenCpReT (n = 0, 1) differs from that for MenCpReT (n = 2–5). The (M – 2CO)+ ions have maximum intensity in n = 0, 1 complexes, and the (M – 2CO – H2)+ ions, in n = 2–5 complexes. H2 elimination from (M – 2CO)+ is typical of rhenium π-cyclopentadienyl complex fragmentation, where the number of methyl groups in the Cp ring is > 1, and seems to occur with participation of the Re atom. 相似文献
10.
Reaction between cis-[Mo(CO)2(dmpe)2] (dmpe =Me2PCH2CH2PMe2) and organic π-acids tetracyanoethene (TCNE), 1,2,4,5-tetracyanobenzene (TCNB) and 1,3,5-trinitrobenzene (TNB) proceeds via electron transfer from the metal complex, which is oxidised to the 17-electron trans-[Mo(CO)2(dmpe)2]+ ion, to the organic acceptor which is reduced to the radical anion. The final products of the reactions are characterised ascis-[Mo{C2(CN)3} (CO)2(dmpe)2] [CN], cis-[Mo{C6H2(CN)4} (CO)2(dmpe)2] [C6H2(CN)4]8 and [Mo(CO)2(dmpe)2 · 2 C6H3(NO2)3] by analysis and spectroscopic (IR, NMR, ESR) measurements which are compared with those of cis-[MoX(CO)2(dmpe)2]X (X = Cl, Br, I) and fac, fac-[Mo2Cl4(CO)4(dmpe)3]. The reaction of cis-[Cr(CO)2(dmpe)2] with TCNE gives trans-[Cr(CO)2(dmpe)2]+ [TCNE]? only. 相似文献
11.
The kinetic energy dependence of collision-induced dissociation (CID) of dicobalt ion (Co
2
+
) with He, Ar, and Xe has been investigated using guided ion-beam mass spectrometry. The change in efficiency of CID as the target gas is changed is in general agreement with previous CID studies of other systems: the cross section with Ar is 0.5 that with Xe, and no product ions are found with He. By varying the conditions under which the reactant ions are formed, the degree of internal excitation of the dicobalt ions is changed. The internal energies can be characterized by a Maxwell-Boltzmann distribution. We find that CID and reactions with O2 and CO are very sensitive to Co
2
+
internal energy. The bond-dissociation energy derived from this work is Do(Co
2
+
)=2.75±0.10 eV (63.4±2.3 kcal/mol). The Co
2
+
results are compared with a previous study of Fe
2
+
. 相似文献
12.
《Journal of Inorganic and Nuclear Chemistry》1981,43(3):431-435
The behavior of the isolated Mo(PF3)x(CO)6−x species under mild thermal neutron irradiation conditions has been examined. It has been established that these compounds are sufficiently stable so that heat and γ-irradiation will not complicate the interpretation of the hot-atom events. The retention of 99Mo in the parent compound upon a 98Mo(n, γ)99Mo reaction is markedly reduced by the substitution of PF3 into Mo(CO)6. The 99Mo formed from a single species like Mo(PF3)3(CO)3 is found predominantly in “inorganic” form (about 80%). The fraction in the form of 99Mo(PF3)x(CO)6−x species has a composition strongly biased to x = 0–2. 相似文献
13.
Feketeová L Khairallah GN Brunet C Lemoine J Antoine R Dugourd P O'Hair RA 《Rapid communications in mass spectrometry : RCM》2010,24(22):3255-3260
Electrospray ionization (ESI) of tryptophan gives rise to multiply charged, non‐covalent tryptophan cluster anions, [Trpn–xH]x?, in a linear ion trap mass spectrometer, as confirmed by high‐resolution experiments performed on a Fourier transform ion cyclotron resonance (FT‐ICR) mass spectrometer. The smallest multiply charged clusters that can be formed in the linear ion trap as a function of charge state are: x = 2, n = 7; x = 3, n = 16; x = 4, n = 31. The fragmentation of the dianionic cluster [Trp9–2H]2? was examined via low‐energy collision‐induced dissociation (CID), ultraviolet photodissociation (UVPD) at 266 nm and electron‐induced dissociation (EID) at electron energies ranging from >0 to 30 eV. CID proceeds mostly via charge separation and evaporation of neutral tryptophan. The smallest doubly charged cluster that can be formed via evaporation of neutral tryptophans is [Trp7–2H]2?, consistent with the observation of this cluster in the ESI mass spectrum. UVPD gives singly charged tryptophan clusters ranging from n = 2 to n = 9. The latter ion arises from ejection of an electron to give the radical anion cluster, [Trp9–2H]?.. The types of gas‐phase EID reactions observed are dependent on the energy of the electrons. Loss of neutral tryptophan is an important channel at lower energies, with the smallest doubly charged ion, [Trp7–2H]2?, being observed at 19.8 eV. Coulomb explosion starts to occur at 19.8 eV to form the singly charged cluster ions [Trpx–H]? (x = 1–8) via highly asymmetric fission. At 21.8 eV a small amount of [Trp2–H–NH3]? is observed. Thus CID, UVPD and EID are complementary techniques for the study of the fragmentation reactions of cluster ions. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
14.
(pyH)3Mo2Br7(H2O)2 (pyH = Pyridinium cation) was prepared from the solution of (NH4)5Mo2Cl9 · H2O in 1:1 HBr by the addition of pyHBr. The compound has monoclinic unit cell: P 21/n with a = 10.250(4), b = 11.891(4), c = 11.971(3) Å and β = 112.86(2)°. Z = 2, D calcd. = 2.54, D obsd. = 2.52(2) g cm?3. The structure has been refined to the unweighted and weighted residuals of 7.8 and 8.7%. The structure contains Mo2Br6(H2O)22?, C5H6N+ and Br? ions. Short Mo? Mo distance 2.130(4) Å reflects the strong bond. H2O is coordinated to molybdenum at 2.19(3) Å. Distribution of H2O molecules and Br? ions around Mo2 is different from (picH)2Mo2X6(H2O)2 (X = Br, I) and determined by the two-fold axes perpendicular to the Mo? Mo direction and the plane defined by two H2O molecules and 2 Br atoms. Three independent Mo? Br distances are 2.574(4), 2.606(5) and 2.569(5) Å. Specific structure of the Mo2Br6(H2O)22? ion has no synthetic consequences and reaction with neutral aromatic nitrogen bases leads to the known Mo2Br4L4 compounds. 相似文献
15.
《Journal of organometallic chemistry》1987,319(2):213-217
Trimethylamine N-oxide (TMNO)-initiated decarbonylations of Mo(CO)6 followed by phosphine additions yield the complexes Mo(CO)5(Ph2PCH2PPh2), which consists of a unidentate diphosphine, and the dinuclear phosphine-bridged complexes Mo2(CO)10(μ-Ph2P(CH2)nPPh2) (where n = 2, 3) at ambient temperatures. The IR and NMR (1H and 31P) spectroscopic and structural properties of these complexes are presented and discussed. Some thermal analytical data are summarised. 相似文献
16.
《International journal of mass spectrometry》1999,182(2-3):131-141
Two series of bonding isomers of Ni(II) coordination compounds with tetradentate quasimacrocyclic ligands based on S-substituted isothiocarbohydrazides were characterized by electron impact (EI) mass spectrometry and by tandem mass spectrometry methods. Conventional EI mass spectra were more isomer specific than metastable ion (MI) and collision induced dissociation (CID) mass spectra of the molecular ions. The MI (and CID) mass spectra of the isomers were very similar. This effect resulted from a facile randomization of Ni–N bonds in the ions possessing low internal energies, prior to their dissociation. The compounds were found to be convenient precursors for coordinatively unsaturated metal-containing ions, [NiLn]+ and [RNiLn]+ (n = 1, 2; L = NCCH3, NCSCH3; R = OH, NO). Most of these species had a structure of mono- or disolvated nickel ion. The dissociation of [HONiNCCH3]+ ions was consistent with the formation of two isomers: one corresponding to the [HONi]+ ion solvated by acetonitrile and the other is a complex of H2O with [NiNCCH2]+. A structure of [HO,Ni,(NCCH3)2]+ ions was best represented by a five-membered cycle formed by two acetonitrile units and the metal atom with the OH group attached to one of the nitrogen atoms. 相似文献
17.
Talat Yalcin Imre G. Csizmadia Michael R. Peterson Alex G. Harrison 《Journal of the American Society for Mass Spectrometry》1996,7(3):233-242
The unimolecular and low energy collision-induced fragmentation reactions of the MH+ ions of N-acetyl-tri-alanine, N-acetyl-tri-alanine methyl ester, N-acetyl-tetra-alanine, tetra-alanine, penta-alanine, hexa-glycine, and Leu-enkephalin have been studied with a particular emphasis on the formation and fragmentation of B n (n=3,4,5) ions. In addition, the metastable ion fragmentation reactions of protonated tetra-glycine, penta-glycine, and Leu-enkephalin amide have been studied. B n ions are prominent stable species in all spectra. The B n ions fragment, in part, by elimination of CO to form A n ions; this reaction occurs on the metastable ion time scale with a substantial release of kinetic energy (T 1/2=0. 3–0. 5 eV) that indicates that a stable configuration of the B n ion fragments by way of a reacting configuration that is higher in energy than the fragmentation products, A n + CO. Ab initio calculations strongly suggest that the stable configuration of the B3 and B4 ions is a protonated oxazolone formed by interaction of the developing charge with the next-nearest carbonyl group as HX is lost from the protonated species H-(Yyy) n -X · H+. The higher B n ions also fragment, in part, to form the next-lower B ion, presumably in its stable protonated oxazolone form. This reaction is rationalized in terms of the three-dimensional structure of the B n ions and it is proposed that the neutral eliminated is an α-lactam. 相似文献
18.
The formation of negative ions in electron transfer reactions between hyperthermal alkali atoms (Na, K) and WF6 has been studied in the energy range 0–30 eV c.m. Relative cross sections and translational energy thresholds for ion pair formation have been measured, from which the following electron affinities (EA) and bond dissociation energies (D) have been derived: EA(WF6) = 3.7 eV, EA(WF5) = 1.25 eV, D(WF5—F) = 5.1 eV, D)WF5—F?) = 5.4 eV, D(WF?5—F) = 7.6 eV. Several ion molecule reactions are discussed which result in formation of secondary fragmentation ions and WF?7. 相似文献
19.
Gaseous mixtures of germane or methylgermane with ammonia and methylgermane with phosphine have been studied by ion trap mass spectrometry. Rate constants of reactions of the primary ions and of the most important secondary ion species are reported, together with the calculated collisional rate constants and efficiencies of reaction. The GeHn+ (n = 0–3) ions, formed by electron ionization of both GeH4 and CH3GeH3, react with ammonia yielding, among others, the GeHn+ (n = 2–4) ion family, which, in a successive and slow reaction with NH3, only give the unreactive ammonium ion. Also, the CH3GeHn+ (n = 1, 2) species do not form Ge–N bonds, whereas secondary ions of germane, such as Ge2H2+, produce species containing germanium and nitrogen together. In the CH3GeH3/PH3 mixture a great number of ions are formed with rather high rate constants from primary ions of both reagent molecules and from phosphorus containing secondary ions. GePHn+ (n = 2–4) ions further react with methylgermane leading to cluster ions with increasing size such as Ge2PHn+ and Ge2CPHn+. The experimental conditions favoring the chain propagation of ions containing Ge and N, or Ge and P, with or without C, important in the chemical vapor deposition of materials of interest in photovoltaic technology, are discussed. 相似文献
20.
T. Pradeep S. A. Miller R. G. Cooks 《Journal of the American Society for Mass Spectrometry》1993,4(10):769-773
Mass-selected projectile ions in the tens of electronvolt energy range undergo surface-induced dissociation upon collision with a liquid perfluorinated polyether (PFPE) surface. The efficiency of translational-to-vibrational (T-V) energy transfer is similar to that observed for a fluorinated self-assembled monolayer (SAM) surface. The thermometer ion W(CO)^’ was used to detenrrine an average T-V conversion efficiency of 18% in the collision energy range of 30–50 eV. The surface can be bombarded for several hours without displaying any change in the scattered ion products. Ion-surface reactions occur with some projectiles and are analogous to those seen with the fluorinated SAM surface. For example, WF ? + (m=1–5) and W(CO)nF ? + (n=1–2, m=1–2) are generated upon collisions of W(CO) 6 + with the PFPE liquid surface. The ion-surface reactions observed suggest that F atoms and/or CF3 groups are accessible for reaction while the oxygen atoms lie below the outermost surface layer. Chemical sputtering of the liquid surface also occurs and yields common fluorocarbon fragment ions, including CF 3 + , C2F 5 + , and C3F 7 + and the oxygenated product CFO+. The liquid surface is remarkably free of hydrocarbon impurities. Collisions of the pyrazine and benzene molecular ions, both probes for hydrocarbon impurities, resulted in very little protonated pyrazine or protonated benzene. 相似文献