IR多フォトン解離スペクトロスコーピーで測定されたガスのベンゼン-NOカチオンのPi複合構造
Barbara Chiavarino1, Maria Elisa Crestoni, Simonetta Fornarini
1Dipartimento di Studi di Chimica e Tecnologia delle Sostanze Biologicamente Attive, Università di Roma La Sapienza, I-00185 Roma, Italy.
Journal of the American Chemical Society
|September 21, 2006
まとめ
ガス相赤外線複数の光子解離 (IRMPD) スペクトロスコーピーは[C(6) H(6) NO](+) イオンの2つのイソマーを区別しました. この技術では,ベンゼン-NO ((+)) pi複合体と,アロマティック・ニトロゼーション反応の理解に不可欠な,プロトン化ニトロゾベンゼンを成功裏に区別することができました.
科学分野:
- 物理化学 物理化学
- スペクトル顕微鏡検査です.
- 化学イオン化による化学イオン化
背景:
- アロマティック・ニトロゼーション反応には,[C(6) H(6) NO](+) イオンのような重要な中間物質が含まれる.
- これらの中間物質の同位体形態を区別することは,反応機構を理解するために極めて重要です.
- 衝突誘発解離のような以前の方法には,同位体差別の限界があります.
研究 の 目的:
- ガス相 [C(6) H(6) NO](+) イオンを2つの同位体形態で生成し,分析する.
- 構造の解明のために赤外線複数の光子解離 (IRMPD) 光譜を用いる.
- アイソメアの識別のためのIRMPDスペクトルと計算されたIR吸収スペクトルを比較する.
主な方法:
- イオントラップ (FT-ICRとPaulイオントラップ) と結合した自由電子レーザー (FEL) を使用して[C(6) H(6) NO]+) イオンの生成.
- 800~2200cm~-1) の範囲で,IR複数の光子解離 (IRMPD) 光譜を用いたイオンの分析.
- 密度関数理論 (DFT) で計算されたIR吸収スペクトルと実験的なIRMPDスペクトルの比較.
主要な成果:
- [C ((6) H ((6) NO)) ((+)) の2つの異なる同位体形態が生成され,分析されました.
- IRMPDのスペクトロスコピーは,1つの同位体を[ベンゼン,NO](+) のpi複合体として特定し,1963cm(-1) の突出帯によって特徴づけられました.
- ニトロソベンゼンの電気スプレーによるイオン化によって形成された2番目の同位体は,計算上最も安定した同位体であるプロトン化ニトロソベンゼンとして識別されました.
結論:
- IRMPDスペクトロスコピーは,同位体 [C(6) H(6) NO](+) 種を区別するための強力な技術です.
- [ベンゼン,NO](+) pi複合体は,ベンゼンとNO(+) の間の非共性イオンアダクトを表しています.
- この研究は,アロマティック・ニトロゼーション反応の中間物質に関する重要な構造的洞察を提供します.
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