Hendi Zohreh, Jamali Sirous, Chabok Seyed Mohamad J, Jamjah Ali, Samouei Hamidreza, Jamshidi Zahra
Department of Chemistry, Sharif University of Technology, P.O. Box 11155-3516, Tehran, Iran.
Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, United States.
Inorg Chem. 2021 Sep 6;60(17):12924-12933. doi: 10.1021/acs.inorgchem.1c01302. Epub 2021 Aug 17.
Naphthalimide derivatives provide highly versatile self-assembled systems and aggregated forms with fascinating emission properties that make them potential candidates for many applications such as bioimaging and sensing. Although various aggregated species of naphthalimide derivatives have been well documented, little is known about the correlation between their structure and photophysical properties. Here the preparation of a series of tetrameric naphthalimide molecules in which naphthalimide units are linked by bis-N-heterocyclic carbene complexes of coinage metals is described. An in-depth structural investigation into these tetramers has been carried out in solution and the solid state using spectroscopic methods, X-ray crystallography, and computational methods. The experimental and calculated data indicate that the magnitude of the intramolecular interchromophoric π-interactions increases either by an increase in the metal ionic radius or on going from the solid to the solution state. These tetrameric naphthalimide compounds show intramolecular excimeric emissions in the solid and solution phases. However, the quantum yield efficiencies of these excimeric emissions show a trend similar to that for the intramolecular π-interactions either by going from the solution to the solid state or with an increase in the metal ionic radius. Surprisingly, the amine derivative analogues of the silver(I) compound showed an unusual increase in the emission quantum yield efficiency to 92% in solution due to intramolecular hydrogen bonds between amine substituents on adjacent naphthalimde units.
萘酰亚胺衍生物提供了高度通用的自组装体系和具有迷人发射特性的聚集形式，这使其成为生物成像和传感等许多应用的潜在候选物。尽管萘酰亚胺衍生物的各种聚集物种已有充分记录，但关于它们的结构与光物理性质之间的相关性却知之甚少。本文描述了一系列四聚萘酰亚胺分子的制备，其中萘酰亚胺单元通过货币金属的双-N-杂环卡宾配合物相连。利用光谱方法、X射线晶体学和计算方法，对这些四聚体在溶液和固态下进行了深入的结构研究。实验和计算数据表明，分子内发色团间π相互作用的强度会随着金属离子半径的增加或从固态转变为溶液态而增强。这些四聚萘酰亚胺化合物在固态和溶液相中均表现出分子内激基缔合物发射。然而，这些激基缔合物发射的量子产率效率呈现出一种趋势，即无论是从溶液态转变为固态，还是随着金属离子半径的增加，都与分子内π相互作用的趋势相似。令人惊讶的是，由于相邻萘酰亚胺单元上胺取代基之间的分子内氢键作用，银（I）化合物的胺衍生物类似物在溶液中的发射量子产率效率异常增加至92%。
