Macrocycle Co‐Crystals Showing Vapochromism to Haloalkanes

Abstract

Organic co-crystal engineering is a promising method to make multifunctional materials. Here, the marriage of macrocyclic chemistry and co-crystal engineering provides a smart strategy to build vapochromic materials. The macrocycle co-crystals (MCCs) were constructed from p-electron rich pillar[5]arene (P5) and an electron-deficient pyromellitic diimide derivative (PDI) on a 10 g scale. MCCs of P5-PDI are in red owing to the formation of a charge-transfer (CT) complex. After solvent removal, a white crystalline solid with a new structure (P5-PDIa) is yielded, which exhibits selective vapochromic responses to volatile organic compounds (VOCs) of haloalkanes, accompanied by color changes from white to red or orange. Powder and single-crystal X-ray diffraction analyses reveal that the color changes are attributed to the vapor-triggered solid-state structural transformation to form CT co-crystals. Coating films of P5 and PDI on glass showed a visible vapochromic behavior with good reversibility. Scheme 1. Chemical structures of a) co-crystal composition of P5 and PDI, b) haloalkane molecules, and c) other selected VOCs.

Structurally Diverse Macrocycle Co-Crystals for Solid-State Luminescence Modulation

“…Meanwhile, the solid-state photoluminescence quantum yield (PLQY, Ф F ) and uorescence lifetime (τ) were also determined to better understand the optical properties (Supplementary Figs. [29][30][31][32][33][34][35][36]. The results are listed in Table 1, and the corresponding decay curves are presented in Fig.…”

“…29 These co-crystals should be characterized by tunable stoichiometric ratios and interesting properties, the origin of which can be traced back to the polygonal topological structures and the presence of interior cavities. To date, few reports on macrocycle co-crystals (MCCs) based on naphthalenediimide-based molecular triangle, 30,31 pillar[n]arene, [32][33][34][35] and pagoda [4]arene 36 have been reported by Stoddart' group, Huang' group, Chen' group and us. It is challenging to construct MCCs with identical co-components but varying donor (D)-acceptor (A) stoichiometries and study the superstructure-property relationships characterizing the molecules.…”

Supramolecular Tessellations via Pillar[n]arenes-Based Exo–Wall Interactions

“…52−59 Benefiting from the electron-rich 1,4-dialkoxybenzene repeating units of pillar[n]arenes, the inspiration for the supramolecular tessellation was to introduce the charge-transfer (CT) interactions between donors (electron-rich pillar[n]arenes) and acceptors (electron-deficient guests) in the building blocks. 60,61 Propagation of the generated interactions in the CT assemblies was believed to direct the supramolecular tessellations with highly ordered tiling structure and morphology at the molecular level. Here, the electrostatic potential maps of TFB, DFN, and EtP6 were calculated to illustrate the possibility of the external complexation behaviors.…”

A vapochromic dye/graphene coated long-period fiber grating for benzene vapor sensing

“…19,20 Vapochromic materials have drawn intensive attention for visible VOC sensing and are becoming one of the most promising sensitive materials for VOC sensing. [21][22][23] There are several kinds of vapochromic materials, including organic-metal complexes, metal-organic frameworks, porous coordination polymers, and pure organic dyes. 6,14,18,[24][25][26][27][28][29][30] Unlike the extensive studies of metal-containing vapochromic materials, there are only a handful of reports on vapochromic pure organic dyes.…”