Regulation Mechanism of Spin-Orbit Coupling in Charge-Transfer-Induced Luminescence of Imidazopyrazinone Derivatives

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• 作者：Hiroshi Isobe ; Syusuke Yamanaka ; Seiki Kuramitsu ; Kizashi Yamaguchi
• 刊名：Journal of the American Chemical Society
• 出版年：2008
• 出版时间：January 9, 2008
• 年：2008
• 卷：130
• 期：1
• 页码：132 - 149
• 全文大小：608K
• 年卷期：v.130,no.1(January 9, 2008)
• ISSN：1520-5126

文摘

The spin transition in the reactions of the derivatives of imidazo[1,2-a]pyrazin-3(7H)-one (1H)with a triplet molecular oxygen (³O₂) has been investigated by the geometry optimization at the B3LYP/6-31+G(d) level and the evaluation of the electronic matrix elements for spin-orbit coupling (SOC) usingthe full Pauli-Breit SOC operator. The reductive activation for the ³O₂ reaction is affected by the protonactivity and solvent polarity of a surrounding reaction field. In a polar aprotic solvent, a base-promptedanionic substrate may react with ³O₂ in a stepwise manner through complete electron transfer from thesubstrate anion to ³O₂, while the irreversible concerted ³O₂ addition via intersystem crossing may becomecomplete in a less polar solvent. SOC in the thermal decomposition of a resulting peroxide adduct can becontrolled by the protonation state of the substrate. There exists an optimal protonation state for thesuppression of SOC in the charge-transfer-induced luminescence (CTIL) of the peroxide, which is closelyrelated with the ability of a substituent to donate an electron. This will constitute a necessary condition forthe high efficiency of chemi- and bioluminescence.