Vanadium oxide anion cluster reactions with methyl isobutyrate...

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作者：

A Dinca，TP Davis，KJ Fisher，DR Smith，GD Willett

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摘要：

Laser ablation of vanadium pentoxide (V 2O 5) powder produces VO 3-, V 2O 5-, V 3O 7-, V 3O 8-, and V 4O 10- cluster ions which have subsequently been reacted with methyl isobutyrate, methyl methacrylate monomer and its dimer in the ion cell region of a Fourier transform ion cyclotron resonance mass spectrometer. Gas phase ion/molecule chemistry has revealed that reactivity decreases with increased mass of the vanadium oxide cluster anions. VO 3-, V 2O 5- , and V 3O 7- ions react with the three reagents, methyl isobutyrate, methyl methacrylate and its dimer, respectively, either by addition of a whole reagent molecule or an associated fragment. All products formed are a result of parallel processes, V 4O 10- undergoes no reaction for reaction times of up to 500 s, while V 3O 8- adds a water molecule. Although the ions possess a net negative charge, the reactive site toward electron rich reagents such as methyl isobutyrate, methyl methacrylate and its dimer is the under-coordinated vanadium atom. This observation is supported by the lack of reactivity toward the studied reagents by those anions (V 3O 8- and V 4O 10-) whose most likely stable structures contain fully coordinated vanadium atoms

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关键词：

Experimental/ cyclotron resonance Fourier transform spectra ion-molecule reactions laser ablation mass spectra mass spectroscopic chemical analysis molecular clusters negative ions organic compounds vanadium compounds/ vanadium oxide anion cluster VO x- laser ablation FT/ICR mass spectrometry V 2O 5 powder VO 3-+methyl isobutyrate reaction VO 3-+methyl methacrylate reaction VO 3-+methyl methacrylate dimer reaction V 2O 5- V 3O 7- V 3O 8- V 4O 10- cluster ions ion cell region Fourier transform ion cyclotron resonance mass spectrometer gas phase ion+molecule chemistry reagent molecule water molecule reaction times net negative charge reactive site electron rich reagents under-coordinated vanadium atom reactivity stable structures fully coordinated vanadium atoms V 2O 5 VO 3 V 3O 7 V 3O 8 V 4O 10/ A8230F Ion-molecule, ion-ion, and charge-transfer reactions A3640J Interactions of clusters (collisions and reactions) A3520X Molecular mass spectra A8280M Mass spectrometr