Unexpected organic hydrate luminogens in the solid state

• Published in: Nature communications 2021-04, Vol.12 (1), p.2339-2339, Article 2339
• Main Authors: Zhou, Feng, Gu, Peiyang, Luo, Zhipu, Bisoyi, Hari Krishna, Ji, Yujin, Li, Youyong, Xu, Qingfeng, Li, Quan, Lu, Jianmei
• Format: Article
• Language: English
• Subjects: 639/301/357/551; 639/301/923/3931; 639/638/298/398; Atmosphere; Benzimidazoles; Crystal lattices; Crystal structure; Deuterium; Donors (electronic); Emission; Emissions; Fluorescence; Heavy water; Humanities and Social Sciences; Hydrogen; Hydrogen atoms; Hydrogen bonding; Hydrogen bonds; Imines; Intercalation; multidisciplinary; Nitrogen atoms; Photoluminescence; Science; Science (multidisciplinary); Solid state; Water chemistry
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-22685-0

Developing organic photoluminescent materials with high emission efficiencies in the solid state under a water atmosphere is important for practical applications. Herein, we report the formation of both intra- and intermolecular hydrogen bonds in three tautomerizable Schiff-base molecules which comprise active hydrogen atoms that act as proton donors and acceptors, simultaneously hindering emission properties. The intercalation of water molecules into their crystal lattices leads to structural rearrangement and organic hydrate luminogen formation in the crystalline phase, triggering significantly enhanced fluorescence emission. By suppressing hydrogen atom shuttling between two nitrogen atoms in the benzimidazole ring, water molecules act as hydrogen bond donors to alter the electronic transition of the molecular keto form from nπ* to lower-energy ππ* in the excited state, leading to enhancing emission from the keto form. Furthermore, the keto-state emission can be enhanced using deuterium oxide (D 2 O) owing to isotope effects, providing a new opportunity for detecting and quantifying D 2 O. Developing organic photoluminescent materials with high emission efficiencies in the solid state under a water atmosphere is important for practical applications. Here, the authors report the formation of intra- and intermolecular hydrogen bonds in a tautomerizable Schiff base and intercalation of water in the crystal lattice leading to a luminescent organic hydrate.