Structural characterisation methods for supramolecular chemistry that go beyond crystallography

Abstract

In this tutorial review, we present an introduction to structural characterisation techniques commonly used for non-crystalline supramolecular compounds and discuss their application based on recent case studies.

Disassembly Mechanisms and Energetics of Polymetallic Rings and Rotaxanes with Ion Mobility Mass Spectrometry

“…Structure is provided in the form of collision cross sections (CCS), which can be compared to those predicted from theoretical candidate geometries. A number of studies demonstrate the use of IM-MS for the characterization of polymetallic compounds, [1][2][3][4][5] but only a handful have considered the disassembly process. For example, Wesdemiotis and coworkers showed the collisional activation of a terpyridine-based hexameric Cd-complex and subsequently used ion mobility to separate the macrocyclic precursor ion from linear isomers.…”

“…10 µM PhCd and AmNi were used in 500 µM NaI and 4:1 toluene/methanol (PhCd) or 7:3 methanol/DCM (AmNi).The intact thread cation TAm + was observed, whereas no TPh + ions could be detected (FigureS31). b) CCSN2 Distributions of [PhCd + Na] + and its fragments(4,5) at Elab = 90 eV (top) as well as [AmNi + Na] + and its fragments(6,7) at Elab = 120 eV (bottom).…”

Metallosupramolecular cages: from design principles and characterisation techniques to applications

“…This section will introduce the approach for characterising and identifying an unknown cage(s) and studying its host-guest chemistry, discuss recent technique advances/developments as well as highlight challenges to characterisation. Characterisation 47 is reliant on a number of techniques and this section will focus on the three most commonly used techniques-NMR spectroscopy, mass spectrometry (MS) and X-ray crystallography-since these provide complementary information; NMR spectroscopy reveals the symmetry of the resulting self-assembled architecture(s) through the number of ligand environments, mass spectrometry the stoichiometry of the metal ion and organic ligand building blocks and X-ray crystallography the 3-dimensional connectivity of the building blocks within the cage. Finally, advances in computational methods for aiding cage characterisation and design will be discussed.…”

“…There are a number of excellent reviews on the NMR characterisation of supramolecular structures in general. [47][48][49][50] This section will be divided into the NMR characterisation of the: (a) self-assembly process; (b) resulting cage(s); (c) host-guest chemistry.…”

Cyclodextrin-pillar[n]arene hybridized macrocyclic systems

“…As a significant macrocyclic compound 1 in supramolecular chemistry [2][3][4] produced from starch by enzymatic conversion, 5,6 cyclodextrin (CD), 7,8 consisting of several glucose subunits connected by α-1,4 glycosidic bonds (Chart 1), has gained much more attention recently due to its interesting applications in government-approved coronavirus drugs. 9,10 Actually, due to its nano-sized hydrophobic cavity, rigid and particular aqueous solubility and biocompatibility, 13 CD could be used widely in biomedicines such as drug delivery and pharmaceutical, [14][15][16] chemical industries and environmental engineering, 17,18 as well as food and agriculture.…”