作者:Julien E. Gautrot、Philip Hodge、Domenico Cupertino、Madeleine Helliwell
DOI:10.1039/b608628d
日期:——
In this work we present some experimental evidence of the existence of carbonylâÏ electron cloud interactions. Such interactions are analogous to anionâÏ interactions, which have been predicted to be energetically favourable in the case of electron deficient aromatic rings. UV-Visible spectroscopy and cyclic voltammetry results obtained for 9,10-anthraquinone, 1,1â²-bis-9,10-anthraquinone, poly(9,10-anthraquinone-1,4-diyl) and other 1,4-diaryl substituted anthraquinone derivatives are described. It was found that the steric hindrance occurring between the carbonyl groups and the adjacent aromatic substituent forces the plane of the anthraquinone moiety and that of the aromatic substituent to adopt a nearly orthogonal conformation, resulting in relatively strong carbonylâÏ interactions that affect both the UV-Vis absorption spectrum and the reduction potential of the compound. Moreover, in the case of thiophene substituted derivatives, the torsion angle between the anthraquinone moiety and its aromatic substituent is smaller and therefore carbonylâÏ interaction effects are not observed in these compounds.
在这项研究中,我们通过实验证明了羰基电子云相互作用的存在。这种相互作用类似于阴离子âÏ相互作用,根据预测,这种相互作用在缺电子芳香环的情况下能量上是有利的。文中介绍了 9,10-蒽醌、1,1â²-双-9,10-蒽醌、聚(9,10-蒽醌-1,4-二基)和其他 1,4-二基取代的蒽醌衍生物的紫外可见光谱和循环伏安法结果。研究发现,羰基和相邻芳香取代基之间产生的立体阻碍迫使蒽醌分子的平面和芳香取代基的平面采用近乎正交的构象,从而产生相对较强的羰基âÏ相互作用,影响化合物的紫外-可见吸收光谱和还原电位。此外,在噻吩取代的衍生物中,蒽醌分子与其芳香取代基之间的扭转角较小,因此在这些化合物中观察不到羰基相互作用效应。