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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Dual Fluorescence and Excited-State Structural Relaxations in Donor-Acceptor Stilbenes
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Dual Fluorescence and Excited-State Structural Relaxations in Donor-Acceptor Stilbenes

机译:供体-受体Stilbenes中的双重荧光和激发态结构弛豫。

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摘要

The time-resolved fluorescence behavior of two derivatives of 4-(dimethylamino)-4'-cyanostilbene (DCS) bearing a more voluminous (JCS) and less voluminous anilino group (ACS) was investigated in ethanol by reconstructing the emission spectra using picosecond time-resolved single-photon-counting technique. For JCS, these spectra exhibit a temporary isosbestic point, a clear indication of level dynamics between two emitting excited singlet states (LE and CT). Kinetic evaluation yielded a precursor-successor relationship between LE and CT and CT formation time constants of 4 ps for ACS and 8 ps for JCS. This slowing of the reaction for the compound with the larger volume of the donor moiety supports the assumption of a twisting mechanism being a major component of the reaction coordinate. An additional transient red shift of the CT band is observed for both compounds and follows the relatively slow solvation dynamics (ethanol).
机译:通过使用皮秒时间重建发射光谱,研究了乙醇中具有较大体积(JCS)和较小体积苯胺基(ACS)的4-(二甲基氨基)-4'-氰基苯乙烯(DCS)的两种衍生物的时间分辨荧光行为解析的单光子计数技术。对于JCS,这些光谱显示出一个临时的等吸收点,清楚地表明了两个发射的激发单重态(LE和CT)之间的水平动力学。动力学评估得出LE和CT之间的前体-后继关系,ACS的CT形成时间常数为4 ps,JCS的CT形成时间常数为8 ps。对于具有较大体积的供体部分的化合物,反应的这种减慢支持了扭转机制是反应坐标的主要成分的假设。对于这两种化合物,都观察到了CT谱带的另一个瞬时红移,并遵循相对较慢的溶剂化动力学(乙醇)。

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