関連する実験動画

Updated: Jun 6, 2026

Thermochemical Studies of Ni(II) and Zn(II) Ternary Complexes Using Ion Mobility-Mass Spectrometry

Thermochemical Studies of Ni(II) and Zn(II) Ternary Complexes Using Ion Mobility-Mass Spectrometry

Published on: June 8, 2022

値フォトエレクトロンフォトイオン偶然スペクトロスコーピーのメタルロセーンイオンにおける結合エネルギーとイソメリゼーション

Agnes Révész¹, László Szepes, Tomas Baer

¹Institute of Chemistry, Eötvös Loránd University, Budapest, Hungary.

Journal of the American Chemical Society

|December 2, 2010

まとめ

この研究では,値フォトエレクトロンフォトイオン偶然スペクトロスコーピーを用いて,メタルロセネイオン断片化を分析しました. 金属-cyclopentadienyl結合解離エネルギーを決定し,電子構造に関連する傾向を明らかにしました.

科学分野:

物理化学物理化学
スペクトル顕微鏡検査です.
コンピューティング・ケミストリー

背景:

メタロセンのイオンは,有機金属化学において極めて重要です.
解離経路を理解することは,反応性を予測する鍵です.
以前の研究では,詳細なエネルギーとメカニズムに関する洞察が欠けていました.

研究の目的:

メタルロセーンイオン (Cp(2) M(+),M = Cr,Co,Ni) の解離機構,エネルギー,運動を研究する.
0K出現エネルギーとM-Cp結合解離エネルギーを決定する.
結合エネルギーは,メタロセネイオンの電子構造と相関する.

主な方法:

エネルギー選択イオンのための値光電子光イオン偶然スペクトロスコーピー (TPEPICO)
硬直活性化複合体 (RAC) ライス-ラムスペルガー-カッセル-マルカス (RRKM) 理論とモデリングのための簡略化された統計アディアバティックチャネルモデル (SSACM).
構造とパラメータの決定のための密度関数理論 (DFT) 計算 (B3LYP/6-311G(d,p))

主要な成果:

中性サイクロペンタディエニルリガンドの喪失による主要な断片化が観察されました.
小規模な断片化チャネル (CH,C,H,2損失) とコバルトセン (H原子損失) とニケロセン (異体化,H,2損失) の特定の経路が特定されました.
0Kの出現エネルギー (Cr: 10.57 ± 0.14 eV,Co: 11.01 ± 0.13 eV,Ni: 10.18 ± 0.13 eV) とM-Cp結合解離エネルギー (Cr: 5.04 ± 0.16 eV,Co: 5.77 ± 0.15 eV,Ni: 3.96 ± 0.15 eV) を決定した.

結論:

簡略化された統計的アディアバティックチャネルモデル (SSACM) は,解離エネルギーの信頼性の高い結果を提供しました.
M-Cp結合エネルギーの動向は,メタロセネイオンの電子構造と相関しています.
この研究は,金属ロセノイオン化学と反応性を理解するための重要なデータを提供します.

さらに関連する動画

Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F−

Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F⁻

Published on: July 27, 2018

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization

Published on: November 29, 2018

関連する概念動画

Chemical Ionization (CI) Mass Spectrometry

Chemical Ionization (CI) Mass Spectrometry

The molecular ion peak of a molecule in the mass spectrum provides vital information for molecular identification. However, conventional electron impact ionization can lead to the rapid dissociation of some molecular ions before they reach the detector. A milder ionization method is required to increase the lifetime of such ionized analyte molecules. Chemical ionization (CI) is a gas-phase protonation reaction useful for mass-analyzing analyte molecules that are easily protonated to yield the...

Mass Spectrometry: Alkene Fragmentation

Mass Spectrometry: Alkene Fragmentation

Alkenes lose one electron from the unsaturated π bond upon ionization and form stable molecular ions. Further fragmentation of alkenes occurs through three different reaction pathways. The most prominent fragmentation is the cleavage at the allylic position. The resultant allylic carbocation is resonance stabilized. In the mass spectra of terminal alkenes, this fragment appears at a mass-to-charge ratio of 41. In the internal alkenes, where there are two choices of allylic cleavage, the...

Cycloaddition Reactions: MO Requirements for Photochemical Activation

Cycloaddition Reactions: MO Requirements for Photochemical Activation

Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.

Photochemical Electrocyclic Reactions: Stereochemistry

Photochemical Electrocyclic Reactions: Stereochemistry

The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation

π Molecular Orbitals of the Allyl Cation and Anion

π Molecular Orbitals of the Allyl Cation and Anion

An allyl group is a three-carbon conjugated system where the sp³-hybridized allylic carbon is bonded to a CH=CH2 group via a single bond. Allyl anions can be obtained by treating propene with a strong base that can deprotonate methyl groups. Allyl cations are formed as intermediates during substitution reactions involving allylic halides. In both cases, the hybridization of the allylic carbon changes from sp3 to sp2, giving rise to a carbon chain with three sp2-hybridized carbons, each with an...

Thermal Electrocyclic Reactions: Stereochemistry

Thermal Electrocyclic Reactions: Stereochemistry

The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.