Structurally diverse macrocycle co-crystals for solid-state luminescence modulation

• Published in: Nature communications 2024-03, Vol.15 (1), p.2535-8, Article 2535
• Main Authors: Li, Bin, Liu, Lingling, Wang, Yuan, Liu, Kun, Zheng, Zhe, Sun, Shougang, Hu, Yongxu, Li, Liqiang, Li, Chunju
• Format: Article
• Language: English
• Subjects: 639/301/923/966; 639/638/298/398; 639/638/541/961; Charge transfer; Crystal structure; Crystallization; Crystals; Density functional theory; Emission; Emissions; Fabrication; Functional materials; Humanities and Social Sciences; Luminescence; multidisciplinary; Optical properties; Ratios; Science; Science (multidisciplinary); Stoichiometry; Structure-function relationships; Superstructures; X-ray diffraction
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-46788-6

Organic co-crystals offer an opportunity to fabricate organic functional materials. Traditional co-crystals are generally packed following the segregated or mixed stacking mode, leading to the lack of structural and functional diversity. Herein, we report three sets of macrocycle co-crystals with identical co-constitutions. The macrocycle co-crystals differ in the stoichiometric ratios (2:1, 1:1, and 2:3) of the constituents and molecular packing modes. The co-crystals are constructed using triangular pyrene-macrocycle and 1,2,4,5-tetracyanobenzene exploiting exo-wall charge-transfer interactions. Interestingly, the three co-crystals exhibit distinct, tunable emission properties. The corresponding emission peaks appear at 575, 602, and 635 nm, covering yellow via orange to red. The X-ray diffraction analyses and the density functional theory calculations reveal the superstructure-property relationships that is attributed to the formation of different ratios of charge-transfer transition states between the donor and acceptor motifs, resulting in red-shifted luminescence. Organic co-crystals are useful in the fabrication of functional materials, but it is challenging to achieve structural diversity of co-crystals. Here, the authors report nine sets of macrocycle cocrystals with diverse structures and stoichiometric ratios giving different luminescence properties.