IIIn showed broad and structureless absorption curves. However, the trend of bathochromic shift of long wavelength absorption maxima with increasing length of polyene chain suggests that no alternation in the type of light-absorption of polyene chromophore is caused by the introduction of electron donating and withdrawing substituents in the terminal phenyl groups.
α-对
甲氧基苯基-ω-对
硝基苯基多烯(IIIn,n=1-5)是通过对
甲氧基苯基多烯醛(I,n=1-5)与衍生自对硝基苄基三苯基
溴化
鏻(II)的正膦的 Wittig 反应制备的. IIIn 的电子光谱显示出宽且无结构的吸收曲线。然而,随着多烯链长度的增加,长波长吸收最大值的红移趋势表明多烯发色团的吸光类型没有变化是由于在末端苯基中引入给电子和吸电子取代基引起的。