New Structural Insights into Mechanically Interlocked Polymers Revealed by Ion Mobility Mass Spectrometry

Abstract

Mechanically interlocked polymers can possess significant additional physical properties, in comparison to those associated with their constituent parts. Their unique properties make them attractive for a range of potential applications, such as as biomaterials and molecular machines. Their efficient and reproducible synthesis is therefore of much interest. Both their synthesis and subsequent characterization are intriguing yet demanding. The properties of mechanically interlocked polymeric systems depend not only on the properties of their individual components but also on the topology of the subsequent product. Here traveling wave ion mobility mass spectrometry has been used to investigate the structural properties of a polyrotaxane system. Ion mobility studies reveal that this system remains linear in form with increase in size. Both ion mobility studies and tandem mass spectrometry studies indicate that the macrocycle preferentially remains associated with the ammonium moiety of the polymeric repeat unit and is impeded from moving freely along the axle. This is consistent with NMR observations of the average structure. Analysis of mechanically interlocked polymers by ion mobility mass spectrometry provides additional structural insights into these systems relating to dynamics, heterogeneity, and topology. This molecule-specific information is vital in order to understand the origin of a system's functional properties.

Optimization and Insights into the Mechanism of Formation of Mechanically Interlocked Derivatives of Single‐Walled Carbon Nanotubes

“…[13] The mechanical bond provides rotaxanes with unique dynamic properties that have been exploited in the synthesis of molecular machinery. [14][15][16] Most examples of rotaxanes reportedt o date comprise small-molecule organicc omponents,b ut there is ag rowing interest in mechanically interlocked materials, such as polyrotaxanes, [17][18][19][20] rotaxanated metal organic frameworks, [21][22][23] and organic-inorganic rotaxanehybrids. [24][25][26] We have recently introduced the mechanicalb ond as an ew tool for the chemical derivatization of carbon nanotubes, bringingt ogether the fields of SWNT chemistry and MIMs.…”

Separation of catechin epimers by complexation using ion mobility mass spectrometry

“…rapid gas‐phase separation, structural identification of ions by comparison of their experimental drift times with these obtained by computational modeling. Recent applications of IM‐MS include the structural characterization of such biologically relevant (macro)molecules as oligonucleotides, carbohydrates, lipids, proteins and structural description of noncovalent complexes such as chaperonin complexes, the organometallic ruthenium anticancer complex and its adducts with a DNA oligonucleotide, and interlocked polymers …”

“…Recent applications of IM-MS include the structural characterization of such biologically relevant (macro)molecules as oligonucleotides, [1] carbohydrates, [2] lipids, [3] proteins [4] and structural description of noncovalent complexes such as chaperonin complexes, [5] the organometallic ruthenium anticancer complex and its adducts with a DNA oligonucleotide, [6] and interlocked polymers. [7] In contrast to the mass spectrometry (where ions are separated by mass to charge ratio, m/z), in the IM-MS approach they are additionally dispersed by size (ion's collision cross section). [8] Hence, this method makes possible to distinguish between many types of ions such as isomers, isobars and conformers that differ in the ion's collision cross section values.…”

Mehrdimensionale Massenspektrometrie von synthetischen Polymeren und modernen Materialien

“…MS‐Dimension die Dekonvolution des chemischen Rauschens und die Trennung von Ionen sowohl nach dem Ladungszustand als auch nach der Größe/Form, wodurch der Dynamikbereich vergrößert, die Nachweisempfindlichkeit erhöht und die Spektreninterpretation erleichtert wird. Diese Vorteile haben dazu geführt, dass sich die IM‐MS als effektive Analysenmethode zur Charakterisierung komplexer Gemische aus polymeren Isomeren, Isobaren oder Konformeren, supramolekularen Aggregaten, Polymer‐Polypeptid‐Hybridmaterialien und Polymeren, die sich in der Struktur oder der Chiralität unterscheiden, etabliert hat. In den Abschnitten 4.1–4.3 wird der Nutzen der IM‐MS anhand ausgewählter Studien zu supramolekularen Polymeren, Hybridmaterialien und Produkten der thermischen Desorption/Zersetzung nichtionisierbarer Polymere veranschaulicht.…”