Gas Phase Chemistry of Bis(pentamethylcyclopentadienyl)samarium

and, Joaquim Marçalo; Matos, António Pires de; Evans, William J.

doi:10.1021/om9504359

Cited by 24 publications

(34 citation statements)

References 29 publications

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“…Table shows that the metal ions examined fall into two distinct groups on the basis of the reaction pathways traversed. One group of metal ions, Sm + , Eu + , Tm + , Yb + , and the group 2 ions, Ca + , Sr + , and Ba + , form the M(C 5 Me 4 CH 2 ) + ion as the main primary product, with variable contributions from M(C 5 Me 5 ) + and M(C 5 Me 4 H) + ions and from M(C 5 Me 4 ) + in the case of Tm + . The second group of metal ions, the remainder of the lanthanide ions, as well as the group 3 ions, Sc + and Y + , give rise to a large number of products that correspond to single and multiple losses of neutral species, such as H 2 , CH 4 , and other small hydrocarbon molecules, and at the same time do not lead to the formation of M(C 5 Me 5 ) + and M(C 5 Me 4 H) + ions.…”

Section: Resultsmentioning

confidence: 99%

“…The primary products of the reactions of C 5 Me 5 H with the ions Eu + , Tm + , Yb + , Ca + , Sr + , and Ba + showed similar reactivities to that observed previously in the samarium case: 5 formation of the M(C 5 Me 5 ) 2 + ion from the M(C 5 Me 4 CH 2 ) + ion (with a minor contribution from M(C 5 Me 4 CH 2 ) 2 + 37 ), adduct formation in the case of the M(C 5 Me 5 ) + ion, and ligand exchange plus adduct formation in the case of the M(C 5 Me 4 H) + ion. Convincing evidence was presented in the case of Sm + for the formulation of M(C 5 Me 5 ) 2 + as the metallocene . The absence of stable trivalent states for the alkaline-earth elements could raise doubts concerning the ligation of the cyclopentadienyl moieties in the group 2 M(C 5 Me 5 ) 2 + products.…”

Section: Resultsmentioning

confidence: 99%

“…In the last two decades, an extensive chemistry has developed for organolanthanide compounds containing the pentamethylcyclopentadienyl ligand, C 5 Me 5 . − In an effort to further explore the chemistry of organolanthanide species, we have recently described the first gas-phase ion chemistry experiments involving a lanthanide metallocene, namely the bis(pentamethylcyclopentadienyl)samarium complex, Sm(C 5 Me 5 ) 2 , which showed remarkable similarities with the gas-phase behavior of d transition element metallocenes …”

Section: Introductionmentioning

confidence: 99%

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Reactivity of Lanthanide, Group 2, and Group 3 Metal and Metal Oxide Cations with Pentamethylcyclopentadiene: Gas-Phase Synthesis of Cyclopentadienyl Cations

and¹,

Matos²,

Evans

1997

Organometallics

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The gas-phase reactivity of lanthanide (Ln+ = La+−Lu+), group 2 (Ca+, Sr+, and Ba+), and group 3 (Sc+ and Y+) cations, and of their corresponding monoxide ions MO+, with pentamethylcyclopentadiene (C5Me5H) was studied by Fourier transform ion cyclotron resonance mass spectrometry. The reactivity of Eu+, Tm+, Yb+, and the alkaline earth metal ions was similar to that observed previously for Sm+, namely formation of the fulvenide ion M(C5Me4CH2)+ as the main primary product and the metallocene ion M(C5Me5)2 + as the main secondary product. With Sc+, Y+, and the remaining lanthanide series ions, several other species were observed in the primary reactions, corresponding to single and multiple losses of neutral molecules such as H2 and CH4. These differences in reactivity appear to correlate with the accessibility of reactive excited state electron configurations of the metal ions. In the case of the metal oxide cations MO+, the reactivity with pentamethylcyclopentadiene appears to be determined by the strength of the M+−O bonds. The ions with the strongest bonds, LaO+, CeO+, PrO+, and NdO+, formed M(C5Me5)(OH)+ as the sole primary product, which reacted further, eliminating water, to give the metallocene ion M(C5Me5)2 +. ScO+, YO+, and the lanthanide series ions SmO+, GdO+−TmO+, and LuO+ yielded MO(C5Me4CH2)+ and M(C5Me4CH2)+ as the primary products in addition to M(C5Me5)(OH)+. These metal oxides gave M(C5Me4CH2)2 + and M(C5Me5)2 + as secondary products. The ions with the weakest M+−O bonds, EuO+, YbO+, CaO+, SrO+, and BaO+, formed MOH+ as a primary product and M(C5Me5)+ as a secondary product.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Reactivity of Lanthanide, Group 2, and Group 3 Metal and Metal Oxide Cations with Pentamethylcyclopentadiene: Gas-Phase Synthesis of Cyclopentadienyl Cations

and¹,

Matos²,

Evans

1997

Organometallics

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“…1 Although early investigations of metal ion-hydrocarbon reactions focused primarily on first-row transition metals, 2 recent studies have proceeded to examine lanthanide ions (Ln + ). [3][4][5][6][7][8] Whereas condensed-phase organolanthanide chemistry is largely similar across the series, 9 substantial systematic discrepancies have been revealed in the corresponding gas-phase Ln + chemistries. 7 Some of these distinctions are explained by the Ln + ground state electronic configurations and variations in the energy required to promote a nonbonding 4f electron to a valence 5d or 6s reactive orbital.…”

Section: Introductionmentioning

confidence: 99%

Gas-Phase Organolanthanide (Ln) Chemistry: Formation of Ln⁺−{Benzene} and Ln⁺−{Benzyne} Complexes by Reactions of Laser-Ablated Ln⁺ with Cyclic Hydrocarbons

Gibson

1996

J. Phys. Chem.

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Nascent laser-ablated lanthanide metal ions, Ln + , were reacted with cyclohexacarbons, C 6 H 6+2n (n ) 0, 1, 2, or 3), and the resulting organometallic complex ions, {Ln + }-{C p H q }, were identified by time-of-flight mass spectrometry. Cyclohexane and cyclohexadiene were especially reactive, primarily undergoing one or more dehydrogenations to produce adduct ions corresponding to the benzene and benzyne complexes, {Ln + }-{C 6 H 6 } and {Ln + }-{C 6 H 4 }. Also identified as minor products were the "sandwich" complexes, {C 6 H 6 }-{Ln + }-{C 6 H 6 }. Carbon-carbon bond activation was generally an unimportant reaction channel, with small yields of {Ln + }-{C p H q } for p e 5. Significant differences were observed in product yields and distributions between the several Ln + studied, providing the following comparative reactivities: Ce unreactive]. These differences are explained by the metal ion ground state electronic configurations (typically 4f n-1 6s 1 ) and promotion energies (PE) for excitation of a (nonbonding) 4f electron to a valence 5d orbital. For example, upon reaction with 1,3-cyclohexadiene, Eu + (PE ) 394 kJ mol -1 ) was virtually inert while Tb + (PE ) 38 kJ mol -1 ) produced abundant Tb + ‚{C 6 H 6 }. The distinctive Ln + reactivities indicate that most ablated Ln + were in the ground or a low-lying (j0.3 eV) electronic state. Contrasting the reactivities of two or more Ln + co-ablated from a multicomponent target circumvented effects of experimental variables and provided especially reliable comparative reactivities. In addition to the primary chemical effects, variations in product abundances with ion velocity indicated enhanced H 2 loss for high-energy ion-molecule collisions.

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“…The reactivity of lanthanide and actinide ions with hydrocarbons and other organic molecules in the gas phase has received considerable attention in recent times, compared with the small number of reports in the last two decades in which the reactivity of d transition-metal ions was extensively studied. − This recent research involving the f-block ions has been mainly due to efforts of our groups, − of Schwarz and co-workers, − and more recently of Gibson, , expanding previous work from the groups of Beauchamp, − Freiser, − Armentrout, , and Geribaldi. − Concerning the reactivity of actinide ions with organic molecules in particular, reports to date include ion-beam studies of the reactions of U + with CD 4 , , CH 3 F, CH 3 Cl, and CCl 4 , a preliminary Fourier transform ion cyclotron resonance mass spectrometric (FT-ICR/MS) study of the reactivity of U + with 1,3,5-tri- tert -butylbenzene and 2,4,6-tri- tert -butylphenol, and very recent FT-ICR/MS studies of the reactions of U + 15 and Th + 11 with alkanes and alkenes.…”

Section: Introductionmentioning

confidence: 99%

Gas-Phase Actinide Ion Chemistry: FT-ICR/MS Study of the Reactions of Thorium and Uranium Metal and Oxide Ions with Arenes

Marçalo¹,

Leal²,

Matos³

et al. 1997

Organometallics

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Gas-phase reactions of M+, M2+, MO+ (M = Th and U), and UO2 + with several arenes (benzene, naphthalene, toluene, mesitylene, hexamethylbenzene, and 1,3,5-tri-tert-butylbenzene) have been studied by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR/MS). For M+ ions C−H and/or C−C bond activation was observed in the primary reactions for all of the arenes studied. MO+ and UO2 + ions yielded the adduct species, with the exceptions of the reactions of MO+ with hexamethylbenzene and 1,3,5-tri-tert-butylbenzene, for which bond activation products also formed. In the M2+ reactions charge-transfer products dominated, but formation of doubly charged bond activation products was also observed with all the arenes. Product distributions and reaction rate constants are reported and related to the electronic configurations of the reacting ions, the polarizabilities of the arenes, and the energetics of the different reactions.

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Gas Phase Chemistry of Bis(pentamethylcyclopentadienyl)samarium

Cited by 24 publications

References 29 publications

Reactivity of Lanthanide, Group 2, and Group 3 Metal and Metal Oxide Cations with Pentamethylcyclopentadiene: Gas-Phase Synthesis of Cyclopentadienyl Cations

Reactivity of Lanthanide, Group 2, and Group 3 Metal and Metal Oxide Cations with Pentamethylcyclopentadiene: Gas-Phase Synthesis of Cyclopentadienyl Cations

Gas-Phase Organolanthanide (Ln) Chemistry: Formation of Ln⁺−{Benzene} and Ln⁺−{Benzyne} Complexes by Reactions of Laser-Ablated Ln⁺ with Cyclic Hydrocarbons

Gas-Phase Actinide Ion Chemistry: FT-ICR/MS Study of the Reactions of Thorium and Uranium Metal and Oxide Ions with Arenes

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Gas Phase Chemistry of Bis(pentamethylcyclopentadienyl)samarium

Cited by 24 publications

References 29 publications

Reactivity of Lanthanide, Group 2, and Group 3 Metal and Metal Oxide Cations with Pentamethylcyclopentadiene: Gas-Phase Synthesis of Cyclopentadienyl Cations

Reactivity of Lanthanide, Group 2, and Group 3 Metal and Metal Oxide Cations with Pentamethylcyclopentadiene: Gas-Phase Synthesis of Cyclopentadienyl Cations

Gas-Phase Organolanthanide (Ln) Chemistry: Formation of Ln+−{Benzene} and Ln+−{Benzyne} Complexes by Reactions of Laser-Ablated Ln+ with Cyclic Hydrocarbons

Gas-Phase Actinide Ion Chemistry: FT-ICR/MS Study of the Reactions of Thorium and Uranium Metal and Oxide Ions with Arenes

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Gas-Phase Organolanthanide (Ln) Chemistry: Formation of Ln⁺−{Benzene} and Ln⁺−{Benzyne} Complexes by Reactions of Laser-Ablated Ln⁺ with Cyclic Hydrocarbons