Issue 9, 2019

2H NMR reveals liquid state-like dynamics of arene guests inside hexameric pyrogallol[4]arene capsules in the solid state

Abstract

The dynamics of guests in molecular encapsulation complexes have been studied extensively in solution, but the corresponding behavior of those guests when the capsules are present in the solid state is not as well understood. Here we report on comparative solution 1H and solid-state 2H NMR measurements of encapsulation complexes of fluorene(-d2), fluoranthene(-d10), and pyrene(-d10) in pyrogallol[4]arene hexamers assembled in the solid state by ball milling. In solution, the 1H spectra show that these rigid guests tumble and exchange positions quickly within the capsules’ interiors, with the exception of pyrene, which has slower tumbling and positional exchange. Static solid-state 2H NMR using the deuterated guests shows that, when the capsules are in the solid state, their guests retain the liquid state-like dynamics observed for the capsules in solution. When the pyrogallol[4]arene hexamers’ pendant decyl groups were substituted with propyl groups, guest dynamics in the solid state were slowed. We propose that these pendant alkyl groups form an interdigitated and dynamic waxy domain surrounding the capsules in the solid state, and that the greater mobility of the decyl groups is translated across the walls of the host, resulting in more rapid guest dynamics in the capsules’ interiors.

Graphical abstract: 2H NMR reveals liquid state-like dynamics of arene guests inside hexameric pyrogallol[4]arene capsules in the solid state

Supplementary files

Article information

Article type
Research Article
Submitted
11 ፌብሩ 2019
Accepted
29 ማርች 2019
First published
01 ኤፕሪ 2019

Org. Chem. Front., 2019,6, 1361-1366

Author version available

2H NMR reveals liquid state-like dynamics of arene guests inside hexameric pyrogallol[4]arene capsules in the solid state

I. J. Islas, D. Stengel, C. A. Garcia, J. B. Addison, G. N. Samaan, G. P. Holland and B. W. Purse, Org. Chem. Front., 2019, 6, 1361 DOI: 10.1039/C9QO00232D

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements