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Titolo:
Fe(CH4)(n)(+) and Ni(CH4)(n)(+) clusters: experimental and theoretical bond energies for n=1-6
Autore:
Zhang, Q; Kemper, PR; Bowers, MT;
Indirizzi:
Univ Calif Santa Barbara, Dept Chem, Santa Barbara, CA 93106 USA Univ Calif Santa Barbara Santa Barbara CA USA 93106 Barbara, CA 93106 USA
Titolo Testata:
INTERNATIONAL JOURNAL OF MASS SPECTROMETRY
fascicolo: 1-3, volume: 210, anno: 2001,
pagine: 265 - 281
SICI:
1387-3806(20011001)210:1-3<265:FANCEA>2.0.ZU;2-H
Fonte:
ISI
Lingua:
ENG
Soggetto:
ASSISTED MECHANISM; BINDING-ENERGIES; POSITIVE-IONS; GAS-PHASE; METAL; ACTIVATION; METHANE; LIGAND; X=1-4; ATOMS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
34
Recensione:
Indirizzi per estratti:
Indirizzo: Bowers, MT Univ Calif Santa Barbara, Dept Chem, Santa Barbara, CA 93106 USA Univ Calif Santa Barbara Santa Barbara CA USA 93106 93106 USA
Citazione:
Q. Zhang et al., "Fe(CH4)(n)(+) and Ni(CH4)(n)(+) clusters: experimental and theoretical bond energies for n=1-6", INT J MASS, 210(1-3), 2001, pp. 265-281

Abstract

Measurements are reported for sequential clustering of CH4 to Fe+ and Ni+ ions under equilibrium conditions. Detailed density functional theory calculations were performed to provide structural and electronic configuration information and to help analyse and interpret the experimental data. The calculations indicate that the first two CH, ligands add on opposite sides of the Fe+ core ion in an eta (3) configuration, in an eta (2) configuration for Ni+, and induce significant s/d hybridization on both of the metal centers. This hybridization both reduces Pauli repulsion and fosters sigma donation from the ligands into the 4s orbital on M+. Another major covalent interaction is the donation from CH4 into the singly occupied d orbital(s) on M for both eta (2) and eta (3) configurations. For Fe+ the change of spin state, from D-6 (3d(6)4s(1)) to F-4 (3d(7)), takes place during the clustering of the first methane ligand. The clustering of the third CH4 to Fe+ and Ni+, unlike Co+(CH4)(3), is not impeded by the s/d hybridization present for n = 1 and 2. The interactions of all three CH4 ligands, with the Fe+ and Ni+ core are essentially the same. The m/z 120 peak [nominally Fe+(CH4)(4)]and the m/z 122 peak [nominally Ni+(CH4)(4)] were formed irreversible in the temperature range from 270 to 170 K, probably due to the persistent impurity we reported earlier for the Co+ system. The n = 5 and 6 ligands are very weakly bound and begin a second solvation shell. Calculations suggest the n = 6 cluster forms a pseudo octahedral complex. (C) 2001 Elsevier Science B.V.

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Documento generato il 11/07/20 alle ore 19:23:20