Department of Creative Engineering, National Institute of Technology, Kitakyushu College, 5-20-1 Shi-i, Kokuraminami-ku, Kitakyushu 802-0985, Japan.
Advanced School of Creative Engineering, National Institute of Technology, Kitakyushu College, 5-20-1 Shi-i, Kokuraminami-ku, Kitakyushu 802-0985, Japan.
Molecules. 2017 Oct 26;22(11):1816. doi: 10.3390/molecules22111816.
Photoluminescent divinylbipyrroles were synthesized from 3,3',4,4'-tetraetyl-2,2'-bipyrrole-5,5'-dicarboxaldehyde and activated methylene compounds via aldol condensation. For mechanistic clarity, molecular structures of Meldrum's acid- and 1,3-dimethylbarbituric acid-derived divinylbipyrroles were determined by single-crystal X-ray diffraction. Photoluminescent properties of the synthesized divinylbipyrroles in dichloromethane were found to be dependent on the presence of electron withdrawing groups at the vinylic terminal. The divinylbipyrroles derived from malononitrile, Meldrum's acid, and 1,3-dimethylbarbituric acid showed fluorescent peaks at 553, 576, and 602 nm respectively. Computational studies indicated that the alkyl substituents on the bipyrrole 3 and 3' positions increased energy level of the highest occupied molecular orbital (HOMO) compared to the unsubstituted derivatives and provided rationale for the bathochromic shift of the ultraviolet-visible (UV-Vis) spectra compared to the previously reported analogs.
通过醇醛缩合反应，从 3,3',4,4'-四乙基-2,2'-联吡啶-5,5'-二甲酸醛和活性亚甲基化合物合成了光致发光的二乙烯基联吡啶。为了清楚地阐明机理，通过单晶 X 射线衍射确定了源自 Meldrum 酸和 1,3-二甲基巴比妥酸的二乙烯基联吡啶的分子结构。在二氯甲烷中，合成的二乙烯基联吡啶的光致发光性质取决于在乙烯基末端是否存在吸电子基团。来自丙二腈、Meldrum 酸和 1,3-二甲基巴比妥酸的二乙烯基联吡啶分别在 553、576 和 602nm 处显示出荧光峰。计算研究表明，与未取代的衍生物相比，联吡啶 3 和 3' 位上的烷基取代基增加了最高占据分子轨道（HOMO）的能级，并为紫外-可见（UV-Vis）光谱的红移提供了依据，与之前报道的类似物相比。
