Disappeared supramolecular isomer reappears with perylene guest

Abstract

Among different types of polymorphism, disappearing polymorphism deals with the metastable kinetic form which can not be reproduced after its first isolation. In the world of coordination polymers (CPs) and metal–organic frameworks (MOFs), despite the fact that many types of supramolecular isomerism exist, we are unaware of disappearing supramolecular isomerism akin to disappearing polymorphism. This work reports a MOF with dia topology that could not be reproduced, but subsequent synthesis yielded another supramolecular isomer, a double-pillared-layer MOF. When perylene was added in the same reaction, the disappeared dia MOF reappeared with perylene as a guest in the channels. Interestingly, the photoluminescence of the dia MOF with a perylene guest is dominated by the emission of the guest molecule. The influence of guest molecules on the stabilization of the supramolecular isomers of a MOF opens up a strategy to access MOFs with different structures.

π-Stacking among the Anthracenyl Groups of a Copper Complex Resulted in Doubling of Unit Cell Volume To Provide New Polymorphs

“…The formations of Herringbone structures are guided by solvent, host–guest interactions, effect of substituents, and stimuli . Stacking among the phenyl rings occur in several ways such as edge-to-face, face-to-face, or oblique types, as illustrated in Figure a . It may be seen that the face-to-face parallel molecules either having eclipsed (Figure a (iii) or partly eclipsed (Figure a (vi)) geometries may be further arranged in different ways at translated positions in the case of eclipsed pairs, or as in a uni-directional manner (Figure a (vii)) or in bi-directions (Figure a (viii)).…”

Transformation of One-Dimensional Ladders into Two-Dimensional Networks via Simple Solvate Exchange in Single-Crystal-to-Single-Crystal Mode

“…Studies on self-assembly and related synthetic methodologies have provided information useful to the structural control and development of metal–ligand framework materials. − Tuning of supramolecular isomers, a challenging issue, can aid fundamental understanding and facilitate development of functional molecular coordination materials. − Such an efficient methodology for construction of desirable molecular coordination materials from building blocks is a hot topic and has already yielded exciting advances in various task-specific practical functionalities such as photoelectronic devices, ion exchangers, desiccants, molecular sieves, sensors, catalysts, negative Poisson’s ratio materials, guest-preorganizers, and state-transition materials. − Generally, self-assembly of metal ions with designed organic ligands gives rise to serendipitous products containing supramolecular isomers − owing to the intrinsic presence of unusually weak interactions − and reaction conditions related to solvent, temperature, pH, photoenergy, and the crystallization method. − As for the diverse supramolecular isomers possibly obtainable from identical building blocks, research into selective product formation is keenly required and can provide a good opportunity for investigation of the detailed structure–property relationships of functional coordination polymers. − …”

Regioisomers of singly bridged calix[6]crown-6 and their heavy alkali metal complexes: a molecular baseball glove for caesium(I)

“…Since the pioneering works of Pedersen, Lehn and Cram, supramolecular chemistry of macrocycles is still significant in chemistry and biology because many of the roots and concepts came from the phenomena found in biological process such as molecular recognition, self-assembly, enzyme catalysis and ion transport (Pedersen, 1967;Izatt et al, 1995;Lindoy, 1990;Lehn, 1995). Supramolecular chemistry has been extended to various research areas such as metal-organic frameworks, metal-organic coordination cages, hydrogen-bonded organic frameworks, covalent organic frameworks,stacked frameworks, as well as applications of macrocyclic complexes and continuous studies being carried out (Zhou et al, 2012;Fujita et al, 2005;Cook et al, 2013;Chakraborty et al, 2021;Deng et al, 2020;Ouyang et al, 2017Ouyang et al, , 2018Li et al, 2014Li et al, , 2021Park et al, 2020;Britton et al, 2021;Boer et al, 2019;Braunecker et al, 2018;Hong et al, 2021;Yadava et al, 2020). The advances of experimental instruments for structural analyses including single-crystal X-ray diffraction and high-field NMR have also led such progress.…”