Ion Chemistry of OV(OCH3)3 in the Gas Phase: Molecular Cations and Anions and Their Primary Fragmentations

详细信息    查看全文

• 作者：Detlef Schrö ; der ; Jessica Loos ; Marianne Engeser ; Helmut Schwarz ; Hans-Christian Jankowiak ; Robert Berger ; Roland Thissen ; Odile Dutuit ; Jens Dö ; bler ; and Joachim Sauer
• 刊名：Inorganic Chemistry
• 出版年：2004
• 出版时间：March 22, 2004
• 年：2004
• 卷：43
• 期：6
• 页码：1976 - 1985
• 全文大小：158K
• 年卷期：v.43,no.6(March 22, 2004)
• ISSN：1520-510X

文摘

Trimethyl vanadate(V), OV(OCH₃)₃ (1), is examined by various mass spectrometric means. Photoionizationexperiments yield an ionization energy of IE(OV(OCH₃)₃) = 9.54 ± 0.05 eV for the neutral molecule. The primaryfragmentation of the molecular cation 1⁺, i.e., loss of neutral formaldehyde, can occur via two independent routesof hydrogen migrations to afford the formal V^IV compounds HOV(OCH₃)₂⁺ and OV(OCH₃)(CH₃OH)⁺, respectively.These two pathways are associated with low-lying activation barriers of almost identical height. At elevated energies,direct V-O bond cleavage of 1⁺ allows for expulsion of a methoxy radical concomitant with the generation of thecationic fragment OV(OCH₃)₂⁺, a formal V^V compound. Trimethyl vanadate can also form a molecular anion, 1^-,whose most abundant dissociation channel involves loss of a methyl radical, thereby leading to the formal V^Vcompound OV(OCH₃)₂O^-. Various mass spectrometric experiments and extensive theoretical studies provide detailedinsight into the ion structures and the relative energetics of the primary dissociation reactions of the molecularcations and anions of 1.