4-Substituted 1-Acyloxypyridine-2(1<i>H</i>)-thiones: Experimental and Computational Studies of the Substituent Effect on Electronic Absorption Spectra
作者:Aleksandra Jankowiak、Piotr Kaszynski
DOI:10.1021/jo901522r
日期:2009.10.2
practically substituent independent. Both absorption bands exhibit a modest negative solvatochromic effect. The experimental absorption energies correlate better with excitation energies calculated for N-acetyloxy analogues 2 with the ZINDO//DFT than with the TD-DFT//DFT method. Calculations for a series of 12 N-acetates 2 predict the most blue-shifted π → π* transition for the alkoxy substituent and most
一系列的8个4-取代的1-(金刚烷-1-羰氧基)吡啶-2(1 H)-硫酮(1,X = H,OC 7 H 15,Me,CF 3,SC 3 H 7,CN,COOMe ,和Cl)的制备,并通过MeCN和环己烷中的UV-可见光谱进行表征。所观察到的最低能量过渡,指定为π CS →π*环,表现出显着效果的取代基,λ最大距离333(X = OC范围7 ħ 15)至415纳米(X = CN)。除1b以外的所有酯的实验λ最大值(X = OC 7 H15)与σp −参数相关(ρ= 0.41±0.03,r 2 = 0.95)。相反,吸收带在约295纳米的能量,被指定为π CS →π* CS,实际上是取代基独立的。两个吸收带均显示出适度的负溶剂变色效应。与用TD-DFT // DFT方法相比,用ZINDO // DFT计算的N-乙酰氧基类似物2的实验吸收能更好地与激发能相关。一系列12种N-乙酸酯2的计算预测了