This article is devoted to spectral properties of non-associated 16,17-dihydroxy- and dialkyloxy violanthrones, in order to study the relationship between the nature of alkoxy substituents and the UV/Vis absorption/emission characteristics of these dyes. Solvatochromic and solvatofluorochromic effects of the violanthrone derivatives are investigated as well.

It is found that lengthening of the substituent's alkyl chain in the dye molecules results in a hypsochromic shift of the long-wavelength absorption band and does not influence the position of the emission band. This spectral behavior is explained by the interplay of the electron-releasing ability of the alkoxy substituents and the varying flatness of the dialkoxy substituted violanthrone molecules in their electronic ground and excited states. It is also shown that the position of the absorption and emission bands depends on the intensity of non-specific interactions between dyes and solvents, and linearly correlate with values of the Kirkwood and Lippert parameters.

The results can be useful in process development of new light concentrators and photovoltaic films. Violanthrone derivatives can be used as various mixtures of non-associated and dimer forms with different UV/Vis spectral behavior, depending on dye concentration and medium polarity.

为了研究烷氧基取代基的性质与这些染料的UV / Vis吸收/发射特性之间的关系，本文专门介绍了非缔合的16,17-二羟基和二烷氧基紫蒽酮的光谱性质。还研究了紫罗兰酮衍生物的溶剂变色和溶剂氟变色作用。

已经发现，染料分子中取代基的烷基链的延长导致长波长吸收带的变色移动，并且不影响发射带的位置。该光谱行为由烷氧基取代基的电子释放能力与二烷氧基取代的紫蒽酮分子在其电子基态和激发态下变化的平坦度的相互作用所解释。还显示出吸收带和发射带的位置取决于染料和溶剂之间非特异性相互作用的强度，并且与柯克伍德和利珀特参数的值线性相关。

该结果可用于新的聚光器和光伏膜的工艺开发。紫兰酮衍生物可以用作非缔合形式和二聚体形式的各种混合物，具有不同的UV / Vis光谱行为，具体取决于染料浓度和介质极性。