Issue 42, 2020, Issue in Progress

Thiol–ene coupling reaction achievement and monitoring by “in situ” UV irradiation NMR spectroscopy

Abstract

In this study, the possibilities of a new “in situ” LED UV illumination NMR spectroscopic technique for performing an initiator-free thiol–ene “click” coupling reaction of an allyl-functionalized poly(allyl glycidyl ether) (PAGE) prepolymer with a number of mono- and di-oligo polyethylene glycol (PEG) thiols is demonstrated. The state-of-the-art setup constructed with LEDs as UV light sources that illuminate through optical fibers directly into an NMR testing tube at a fixed wavelength of 365 nm is appropriate for various polymeric materials and biologically active substances. The selected experimental protocol uses a series of periods of irradiation and dark periods, thus providing opportunities to conduct an effective thiol–ene “click” reaction and simultaneously study the kinetics of the photochemical reaction with the exposure time, as well as macromolecular association directly in a solution applying the whole types of NMR methods: from conventional 1H or 13C NMR to diffusion NMR spectroscopy (DOSY). In addition, the molecular mass characteristics of the prepared copolymers were studied by gel-permeation chromatography (GPC). The observed differences in the reaction rates as well as in the size of species formed (the corresponding hydrodynamic radiuses Rh of aggregates) as a result of the coupling process of parent PAGE prepolymers and model PEG thiols were thoroughly discussed and the reaction pathway proposed.

Graphical abstract: Thiol–ene coupling reaction achievement and monitoring by “in situ” UV irradiation NMR spectroscopy

Supplementary files

Article information

Article type
Paper
Submitted
30 Apr 2020
Accepted
18 Jun 2020
First published
02 Jul 2020
This article is Open Access
Creative Commons BY-NC license

RSC Adv., 2020,10, 25214-25222

Thiol–ene coupling reaction achievement and monitoring by “in situ” UV irradiation NMR spectroscopy

N. Toncheva-Moncheva, M. Dangalov, N. G. Vassilev and C. P. Novakov, RSC Adv., 2020, 10, 25214 DOI: 10.1039/D0RA03902K

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. You can use material from this article in other publications, without requesting further permission from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.

To request permission to reproduce material from this article in a commercial publication, 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 commercial 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