ビタミンB12および関連するコブ (III) アラミンにおける超高速興奮状態ダイナミクス
Joseph J Shiang1, Allwyn G Cole, Roseanne J Sension
1Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, USA.
Journal of the American Chemical Society
|January 19, 2006
まとめ
ビタミンB12の興奮状態のダイナミクスは,超高速光譜を用いて研究されました. 軸性リガンドと溶媒の極性によって影響された短期間の中間状態が観察され,リガンドから金属への電荷移転状態に起因しました.
科学分野:
- フォトケミストリー フォトケミストリー
- スペクトロスコーピーは,スペクトロスコーピーを用います.
- バイオケミストリー バイオケミストリー
背景:
- ビタミンB12 (コバラミン) は,様々な生物学的プロセスに不可欠です.
- 興奮状態のダイナミクスを理解することは,その機能を明らかにする鍵です.
研究 の 目的:
- ビタミンB12 (シアノコバラミン,CNCbl) と関連するコブ (III) アラミンの興奮状態の光物理学を調査する.
- 光刺激によって形成される一時的な中間状態を特徴づけるために.
主な方法:
- フェムト秒のトランジント赤外線 (IR) と可視吸収スペクトロスコピー.
- サイアノコバラミン,アジドコバラミン,アクオコバラミンの時間解像度測定.
主要な成果:
- 短期的な興奮状態の急速な形成に続いて,基底状態の回復 (ピコ秒時間スケール).
- 中間状態の寿命は,軸性リガンドのシグマドナー能力と溶媒の極性に依存する.
- Spectraは,リガンドから金属への電荷移転 (LMCT) 状態を示唆し,コリガンド結合が弱体化している.
結論:
- 暫定的な状態は,Co 3d(z2) LMCT状態に対するcorrin ring piである可能性が高い.
- このLMCT状態には,弱体化および延長されたコバルト-軸性リガンド結合が含まれています.
- アキシアルリガンドと溶媒の性質は,興奮状態のリラックス経路に大きな影響を与えます.
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