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The effect of the rate of photoinduced electron transfer on the photodecarboxylation efficiency in phthalimide photochemistry
Journal of Photochemistry and Photobiology A: Chemistry ( IF 4.1 ) Pub Date : 2020-12-28 , DOI: 10.1016/j.jphotochem.2020.113109
Leo Mandić , Margareta Sohora , Branka Mihaljević , László Biczók , Nikola Basarić

Reactivity in photoinduced electron transfer reactions (PET) has been investigated in a series of molecules possessing different distances between the electron donor (carboxylate or alkoxyphenyl) and the phthalimide as the electron acceptor. The molecules were strategically designed to separate the donor and the acceptor by a rigid adamantane spacer or through a peptide backbone with different number of amino acid residues. PET was investigated by laser flash photolysis (LFP). Although previous reports demonstrated that the quantum yields of the photodecarboxylation reaction (ΦR) depend on the distance between the donor and acceptor moieties, the measured lifetimes of the triplet excited state did not provide information on the rates of PET. Due to reversible PET and back electron transfer processes in compounds 1-5, the measured lifetimes correspond to the sum of the rate constants for the disappearance of the charge transfer species. In the series of peptides, three different PET processes take place and LFP provided rate constant for the reactions occurring subsequent to the intrastrand PET between the carboxylate and the alkoxyphenyl radical cation. The understanding of the factors that affect intramolecular PET processes is important for the rational design of different applications.



中文翻译:

邻苯二甲酰亚胺光化学中光诱导电子转移速率对光脱羧效率的影响

已经在一系列电子供体(羧酸盐或烷氧基苯基)和邻苯二甲酰亚胺作为电子受体之间具有不同距离的分子中研究了光诱导电子转移反应(PET)中的反应性。这些分子经过战略性设计,可以通过刚性的金刚烷间隔子或具有不同数目氨基酸残基的肽主链来分离供体和受体。通过激光闪光光解(LFP)研究了PET。虽然以前的报告表明,photodecarboxylation反应的量子产率(Φ ř)取决于供体和受体部分之间的距离,三重激发态的测量寿命无法提供有关PET速率的信息。由于化合物中可逆PET和背面电子转移过程1 - 5,测得的寿命对应于速率常数的电荷转移物质的消失的总和。在一系列肽中,发生了三种不同的PET过程,并且LFP为链内PET在羧酸盐和烷氧基苯基自由基阳离子之间发生的反应提供了速率常数。了解影响分子内PET工艺的因素对于合理设计不同应用非常重要。

更新日期:2021-01-12
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