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連続したイオンペアによる可視光に対するブロミド光酸化
Guocan Li1, Wesley B Swords1, Gerald J Meyer1
1Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States.
Journal of the American Chemical Society
|September 22, 2017
まとめ
ブルミドをルテニウム複合体 ([Ru ((deeb)) ((bpz)) 2+) に加えると,異なる光物理的性質を持つイオンペアを形成する. 第2のイオンペア ([Ru2+, 2Br−]*) は,電子の移動速度が遅いため,発光が強化されている.
科学分野:
- 協調化学
- フォト物理学
- 電子移転
背景:
- ルテニウム (II) ポリピリジル複合体は,その光物理学的および電子移転特性のために広く研究されている.
- イオンペアリングは,電荷のある金属複合体の興奮状態の振る舞いに大きく影響する.
- イオンペア形成とその電子伝送への影響を理解することは,機能的な材料の設計に不可欠です.
研究 の 目的:
- 二塩基メタンの[Ru (deeb) (bpz) ]2+とブロミドイオン間のイオンペアの形成を調査する.
- これらのイオンペア種の光物理的および電子伝送特性を特徴付ける.
- 発光と電子移転の観測された変化を制御する構造的および電子的要因を明らかにする.
主な方法:
- ブロミドを二塩基メタン溶液 [Ru ((deeb)) ((bpz)) ]2+に定位する.
- 1H NMRと光発光 (PL) 測定を含むスペクトル解析
- 密度関数理論 (DFT) の計算は,実験構造データを補完する.
- 電子移転速度の定数を定めるための運動研究.
主要な成果:
- [Ru2+, Br−]+と[Ru2+, 2Br−]*という2つの連続したイオンペアの種が,異なる均衡定数で形成された.
- 最初のイオンペア ([Ru2+, Br−]+*) は非発光であり,第二のイオンペア ([Ru2+, 2Br−]*) は部分発光回復を示した (τ = 65 ± 5 ns).
- ブロミン原子 (Br•) は, Br2•− を形成する主要な電子移転産物として識別された.
- 電子移転速度の定数 (ket) を決定し,DFT計算からのクーロンビック作業項 (ΔGw) と相関させた.
結論:
- ブロミドと[Ru (deeb) (bpz) ]2+のイオンペアリングにより,その光物理的および電子伝送特性が大幅に変化する.
- 第二のイオンペアの増光は,電子移転のギブスの自由エネルギー変化があまり好ましくないことに起因する.
- DFT計算は,イオンペアリングと電子転送プロセスの構造とエネルギーに関する貴重な洞察を提供します.
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