High-resolution IR spectroscopy has been employed to study isolated, switchable [2]rotaxanes. IR absorption spectra of two-station rotaxanes, their separate thread, and macrocycle components, as well as those of the individual stations incorporated into the thread, have been measured in the 1800-1000 cm(-1) region. These spectra have been fully analyzed, aided by quantum chemical predictions of the IR spectra. From these analyses, a comprehensive picture emerges of the conformational structure and binding interactions between the mechanically interlocked components of the rotaxane.
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http://dx.doi.org/10.1021/jp200909v | DOI Listing |
Chemistry
November 2024
Núcleo de Química de Heterociclos (NUQUIMHE), Departamento de Química, Universidade Federal de Santa Maria (UFSM), 97105-900, Santa Maria, Rio Grande do Sul, Brasil.
One of the most recent focuses in supramolecular chemistry is developing molecules designed to exhibit programmable properties at the molecular level. Rotaxanes, which function as molecular machines with movements controlled by external stimuli, are prime candidates for this purpose. However, the controlled synthesis of rotaxanes, especially amide-benzylic rotaxanes with more than two components, remains an area ripe for exploration.
View Article and Find Full Text PDFOrg Biomol Chem
November 2023
Departamento de Química Orgánica, Facultad de Química, Regional Campus of International Excellence "Campus Mare Nostrum", Universidad de Murcia, E-30100 Murcia, Spain.
Sci Rep
June 2018
Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka, 560-0043, Japan.
In the molecular world, molecular ratchets can realize the unidirectional movement in molecular machines. However, construction of artificial molecular ratchets has been still a great challenge. In this study, we investigate the formation of pseudo-rotaxane of a newly designed two-station axis molecule with α-cyclodextrin (α-CD) and the deuteration of acidic protons in the axis in DO by H NMR at varying temperatures.
View Article and Find Full Text PDFChemistry
August 2018
Dipartimento di Chimica "G. Ciamician", Università di Bologna, Via Selmi 2, 40126, Bologna, Italy.
Operating molecular machines are based on switchable systems whose components can be set in motion in a controllable fashion. The presence of nonsymmetrical elements is a mandatory requirement to obtain and demonstrate the unidirectionality of motion. Calixarene-based macrocycles have proved to be very efficient hosts in the design of oriented rotaxanes and of pseudorotaxanes with strict control over the direction of complexation.
View Article and Find Full Text PDFChem Sci
August 2016
Chemistry Research Laboratory , Department of Chemistry , University of Oxford, 12, Mansfield Road , Oxford , OX1 3TA , UK . Email: ; ; Tel: +44 (0)1865 285142.
Two bistable halogen and hydrogen bonding-naphthalene diimide [2]rotaxanes have been prepared and the system incorporating a halogen bond donor anion recognition site is demonstrated to exhibit superior anion induced translational motion of the macrocyclic wheel component relative to the hydrogen bonding analogue. Proton NMR spectroscopy is used to estimate the percentage occupancies of the macrocycle at the respective station and importantly indicates that the halogen bonding rotaxane displays superior positional integrity in competitive protic solvent media as a consequence of strong halogen bond-halide anion binding interactions.
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