Spectroscopy and Photophysics of Monomethyl-Substituted Derivatives of 5-Deazaalloxazine and 10-Ethyl-5-Deaza-Isoalloxazine
作者:Dorota Prukała、Magdalena Taczkowska、Mateusz Gierszewski、Tomasz Pędziński、Marek Sikorski
DOI:10.1007/s10895-013-1320-9
日期:2014.3
Steady-state and time-resolved spectra were used to describe the singlet and triplet states of 8-methyl-5-deazaalloxazine (8-Me-5-DAll), 9-methyl-5-deazaalloxazine (9-Me-5-DAll) and 10-ethyl-5-deaza-isoalloxazine (10-Et-5-DIAll). Solvatochromic properties were described using different polarity scales, including Δf and the four-parameter scale proposed by Catalán. The results indicate that the Catalán scale shows a strong influence of solvent acidity (hydrogen-bond donating ability) on the emission properties of 8-Me-5-DAll and 9-Me-5-DAll. These results indicate the importance of intermolecular solute-solvent hydrogen-bonding interactions in the excited state of these compounds. Contrary to deazaalloxazines, solvent acidity affects the absorption spectra of 10-Et-5-DIAll. Fluorescence lifetimes and quantum yields and also transient absorption spectra were determined for all of the compounds studied. Electronic structure and S 0 -S i , S 0 -T i , T 1 -T i transitions energies and oscillator strengths were calculated using the TD-DFT methods. Theoretical calculations were compared to experimental data.
利用稳态光谱和时间分辨光谱描述了 8-甲基-5-脱氮哒嗪(8-Me-5-DAll)、9-甲基-5-脱氮哒嗪(9-Me-5-DAll)和 10-乙基-5-脱氮异哒嗪(10-Et-5-DIAll)的单线态和三线态。采用不同的极性标度(包括 Δf 和卡塔兰提出的四参数标度)对溶变色特性进行了描述。结果表明,Catalán 标度显示了溶剂酸性(氢键捐赠能力)对 8-Me-5-DAll 和 9-Me-5-DAll 发射特性的强烈影响。这些结果表明了分子间溶质-溶剂氢键相互作用在这些化合物激发态中的重要性。与去氮氮氧化物相反,溶剂的酸性会影响 10-Et-5-DIAll 的吸收光谱。研究人员测定了所有化合物的荧光寿命和量子产率以及瞬态吸收光谱。使用 TD-DFT 方法计算了电子结构和 S 0 -S i 、S 0 -T i 、T 1 -T i 转变的能量和振荡器强度。理论计算结果与实验数据进行了比较。