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A.230nmB.240~260nmC.262~295nmD.305~389nmE.>400nm

A.230nm
B.240~260nm
C.262~295nm
D.305~389nm
E.>400nm
羟基蒽醌的UV吸收峰位置和强度受β-酚羟基影响的是( )。

发布时间:2024-04-25
参考答案

答案:C解析:羟基蒽醌衍生物的紫外光谱与蒽醌母核相似,多数在230nm附近还有一强峰,有五个主要吸收带,即第Ⅰ峰:230nm左右;第Ⅱ峰:240~260nm(由苯样结构引起);第Ⅲ峰:262~295nm(由醌样结构引起);第Ⅳ峰:305~389nm(由苯样结构引起);第Ⅴ峰:>400nm(由醌样结构中的C=O引起)。 以上各吸收带的具体峰位与吸收强度与蒽醌母核上取代基的性质、数目及取代位置有关。峰带Ⅰ的最大吸收波长随分子中酚羟基数目的增多而向红移,但该红移与酚羟基的位置无关。峰带Ⅲ受β-酚羟基的影响,β-酚羟基的存在可使该带红移,且吸收强度增加。峰带Ⅳ受供电基影响,一般规律是α位有-CH3、-OH、-OCH3时,峰位红移,强度降低,而当取代基处于β位时,则吸收峰强度增大。峰带Ⅴ主要受α-羟基的影响,α-羟基数目越多,峰带Ⅴ红移值也越大。

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