open access

https://hdl.handle.net/2115/93021

Giant Crystalline Molecular Rotors that Operate in the Solid State

英語

N-Heterocyclic Carbenes

2023-08-31

Wiley-Blackwell

Angewandte chemie-international edition

e202309694

Molecular motion in the solid state is typically precluded by the highly dense environment, and only molecules with a limited range of sizes show such dynamics. Here, we demonstrate the solid-state rotational motion of two giant molecules, i.e., triptycene and pentiptycene, by encapsulating a bulky N-heterocyclic carbene (NHC) Au(I) complex in the crystalline media. To date, triptycene is the largest molecule (surface area: 245 & ANGS;2; volume: 219 & ANGS;3) for which rotation has been reported in the solid state, with the largest rotational diameter among reported solid-state molecular rotors (9.5 & ANGS;). However, the pentiptycene rotator that is the subject of this study (surface area: 392 & ANGS;2; volume: 361 & ANGS;3; rotational diameter: 13.0 & ANGS;) surpasses this record. Single-crystal X-ray diffraction analyses of both the developed rotors revealed that these possess sufficient free volume around the rotator. The molecular motion in the solid state was confirmed using variable-temperature solid-state 2H spin-echo NMR studies. The triptycene rotor exhibited three-fold rotation, while temperature-dependent changes of the rotational angle were observed for the pentiptycene rotor. Here, we have described the first example of crystalline materials in which bulky iptycene derivatives (triptycene and pentiptycene) exhibit rotational dynamics in the solid state. It is revealed that encapsulation by a large concave NHC ligand provides reasonable rotational space around the central rotator. This platform will enable further design of systems in which large and complicated molecular units exhibit rotational motion in solid.image

学術雑誌論文

Accepted Manuscript

This is the peer reviewed version of the following article: Ando, R., Sato-Tomita, A., Ito, H., Jin, M., Angew. Chem. Int. Ed. 2023, e202309694., which has been published in final form at https://doi.org/10.1002/anie.202309694. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.

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