Pannipara Mehboobali, Asiri Abdullah M, Alamry Khalid A, Arshad Muhammad N, El-Daly Samy A
Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia.
Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia; Center of Excellence for Advanced Materials Research, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia.
Spectrochim Acta A Mol Biomol Spectrosc. 2015 Feb 5;136 Pt C:1893-902. doi: 10.1016/j.saa.2014.10.105. Epub 2014 Nov 1.
The spectral and photophysical properties of two chalcones containing electron donating and accepting groups with intramolecular charge transfer characteristics were synthesized and characterized by (1)H NMR, (13)C NMR and X-ray crystallography. Both compounds show very strong solvent polarity dependent changes in their photophysical characteristics, namely, remarkable red shift in the emission spectra with increasing solvent polarity, large change in Stokes shift, significant reduction in the fluorescence quantum yield; indicating that the fluorescence states of these compounds are of intramolecular charge transfer (ICT) character. The solvent effect on the photophysical parameters such as singlet absorption, molar absorptivity, oscillator strength, dipole moment, fluorescence spectra, and fluorescence quantum yield of both compounds have been investigated comprehensively. For both dyes, Lippert-Mataga and Reichardt's correlations were used to estimate the difference between the excited and ground state dipole moments (Δμ). The interactions of dyes with colloidal silver nanoparticles (Ag NPs) were also studied in ethanol using steady state fluorescence quenching measurements. The fluorescence quenching data reveal that dynamic quenching and energy transfer play a major role in the fluorescence quenching of dyes by Ag NPs.
合成了两种具有分子内电荷转移特性的含供电子和吸电子基团的查尔酮，并通过¹H NMR、¹³C NMR和X射线晶体学对其光谱和光物理性质进行了表征。两种化合物的光物理特性均表现出非常强烈的溶剂极性依赖性变化，即随着溶剂极性的增加，发射光谱出现显著红移，斯托克斯位移变化很大，荧光量子产率显著降低；这表明这些化合物的荧光态具有分子内电荷转移（ICT）特征。全面研究了溶剂对这两种化合物的光物理参数的影响，如单重态吸收、摩尔吸光系数、振子强度、偶极矩、荧光光谱和荧光量子产率。对于这两种染料，使用Lippert-Mataga和Reichardt相关性来估计激发态和基态偶极矩之间的差异（Δμ）。还在乙醇中使用稳态荧光猝灭测量研究了染料与胶体银纳米颗粒（Ag NPs）的相互作用。荧光猝灭数据表明，动态猝灭和能量转移在Ag NPs对染料的荧光猝灭中起主要作用。
