Institute of Physical Chemistry, Polish Academy of Sciences , Warsaw 01-224, Poland.
J Phys Chem A. 2014 Feb 13;118(6):1038-46. doi: 10.1021/jp412139r. Epub 2014 Jan 30.
Three octaalkyl-substituted cyclo[4]naphthobipyrroles, studied in solution in the form of their sulfates, reveal absorption and magnetic circular dichroism (MCD) spectra very similar to those of the parent cyclo[8]pyrrole. A unique feature of these systems is a strong absorption in the near IR region. The analysis of MCD patterns based on a perimeter model reveals a hard-chromophore character of cyclo[4]naphthobipyrroles, i.e., ΔHOMO ≪ ΔLUMO. Comparison of Raman spectra obtained for crystalline samples and solutions, combined with the analysis of absorption and MCD spectra based on quantum chemical calculations reveals that cyclo[4]naphthobipyrroles exist in solutions as undissociated sulfates of the doubly protonated forms.
三种八烷基取代的环己[4]萘并双吡咯，以硫酸盐的形式在溶液中进行研究，其吸收和磁圆二色性（MCD）光谱与母体环己[8]吡咯非常相似。这些系统的一个独特特征是在近红外区域有很强的吸收。基于周长模型的 MCD 模式分析表明，环己[4]萘并双吡咯具有硬生色团的性质，即 HOMO 跃迁能 ΔHOMO 远小于 LUMO 跃迁能 ΔLUMO。对晶体样品和溶液的拉曼光谱进行比较，并结合基于量子化学计算的吸收和 MCD 光谱分析表明，环己[4]萘并双吡咯在溶液中以双质子化形式的未离解硫酸盐存在。
