In-situ EPR Studies of Reaction Pathways in Titania Photocatalyst-Promoted Alkylation of Alkenes

Shona Rhydderch; Russell F. Howe

doi:10.3390/molecules20034055

In-situ EPR Studies of Reaction Pathways in Titania Photocatalyst-Promoted Alkylation of Alkenes

Shona Rhydderch, Russell F. Howe

Chemistry

Research output: Contribution to journal › Article › peer-review

5 Citations (Scopus)

9 Downloads (Pure)

Abstract

In situ EPR spectroscopy at cryogenic temperatures has been used to observe and identify paramagnetic species produced when titania is irradiated in the presence of reactants used in the photocatalytic alkylation of maleimide with t-butyl carboxylic acid or phenoxyacetic acid. It is shown that maleimide acts as an acceptor of conduction band electrons. Valence band holes oxidise t-butyl carboxylic acid to the t-butyl radical and phenoxyacetic acid to the phenoxyacetic acid radical cation. In the presence of maleimide, the phenoxymethyl radical is formed from phenoxyacetic acid. The relevance of these observations to the mechanisms of titania photocatalyst-promoted alkylation of alkenes is discussed.

Original language	English
Pages (from-to)	4055-4070
Number of pages	16
Journal	Molecules
Volume	20
Issue number	3
Early online date	3 Mar 2015
DOIs	https://doi.org/10.3390/molecules20034055
Publication status	Published - 3 Mar 2015

Bibliographical note

Acknowledgments
This work was supported by Engineering and Physical Sciences Research Council (EPSRC) Grant EP/I00372X/1. The EPR spectrometer was purchased under EPSRC Grant EP/F032560/1. We thank Andrew Mills for use of the spectroradiometric measurement system.

Keywords

EPR spectroscopy
titania
photocatalysis
alkene alkylation

Access to Document

10.3390/molecules20034055Licence: CC BY

molecules-20-04055
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. http://creativecommons.org/licenses/by/4.0/
Final published version, 822 KBLicence: CC BY

Cite this

@article{b2f911364fee439fb2ddbf5ea4b488b8,

title = "In-situ EPR Studies of Reaction Pathways in Titania Photocatalyst-Promoted Alkylation of Alkenes",

abstract = "In situ EPR spectroscopy at cryogenic temperatures has been used to observe and identify paramagnetic species produced when titania is irradiated in the presence of reactants used in the photocatalytic alkylation of maleimide with t-butyl carboxylic acid or phenoxyacetic acid. It is shown that maleimide acts as an acceptor of conduction band electrons. Valence band holes oxidise t-butyl carboxylic acid to the t-butyl radical and phenoxyacetic acid to the phenoxyacetic acid radical cation. In the presence of maleimide, the phenoxymethyl radical is formed from phenoxyacetic acid. The relevance of these observations to the mechanisms of titania photocatalyst-promoted alkylation of alkenes is discussed.",

keywords = "EPR spectroscopy, titania, photocatalysis, alkene alkylation",

author = "Shona Rhydderch and Howe, {Russell F.}",

note = "Acknowledgments This work was supported by Engineering and Physical Sciences Research Council (EPSRC) Grant EP/I00372X/1. The EPR spectrometer was purchased under EPSRC Grant EP/F032560/1. We thank Andrew Mills for use of the spectroradiometric measurement system.",

year = "2015",

month = mar,

day = "3",

doi = "10.3390/molecules20034055",

language = "English",

volume = "20",

pages = "4055--4070",

journal = "Molecules",

issn = "1420-3049",

publisher = "MOLECULAR DIVERSITY PRESERVATION INTERNATIONAL-MDPI",

number = "3",

}

TY - JOUR

T1 - In-situ EPR Studies of Reaction Pathways in Titania Photocatalyst-Promoted Alkylation of Alkenes

AU - Rhydderch, Shona

AU - Howe, Russell F.

N1 - Acknowledgments This work was supported by Engineering and Physical Sciences Research Council (EPSRC) Grant EP/I00372X/1. The EPR spectrometer was purchased under EPSRC Grant EP/F032560/1. We thank Andrew Mills for use of the spectroradiometric measurement system.

PY - 2015/3/3

Y1 - 2015/3/3

N2 - In situ EPR spectroscopy at cryogenic temperatures has been used to observe and identify paramagnetic species produced when titania is irradiated in the presence of reactants used in the photocatalytic alkylation of maleimide with t-butyl carboxylic acid or phenoxyacetic acid. It is shown that maleimide acts as an acceptor of conduction band electrons. Valence band holes oxidise t-butyl carboxylic acid to the t-butyl radical and phenoxyacetic acid to the phenoxyacetic acid radical cation. In the presence of maleimide, the phenoxymethyl radical is formed from phenoxyacetic acid. The relevance of these observations to the mechanisms of titania photocatalyst-promoted alkylation of alkenes is discussed.

AB - In situ EPR spectroscopy at cryogenic temperatures has been used to observe and identify paramagnetic species produced when titania is irradiated in the presence of reactants used in the photocatalytic alkylation of maleimide with t-butyl carboxylic acid or phenoxyacetic acid. It is shown that maleimide acts as an acceptor of conduction band electrons. Valence band holes oxidise t-butyl carboxylic acid to the t-butyl radical and phenoxyacetic acid to the phenoxyacetic acid radical cation. In the presence of maleimide, the phenoxymethyl radical is formed from phenoxyacetic acid. The relevance of these observations to the mechanisms of titania photocatalyst-promoted alkylation of alkenes is discussed.

KW - EPR spectroscopy

KW - titania

KW - photocatalysis

KW - alkene alkylation

U2 - 10.3390/molecules20034055

DO - 10.3390/molecules20034055

M3 - Article

SN - 1420-3049

VL - 20

SP - 4055

EP - 4070

JO - Molecules

JF - Molecules

IS - 3

ER -

In-situ EPR Studies of Reaction Pathways in Titania Photocatalyst-Promoted Alkylation of Alkenes

Abstract

Bibliographical note

Keywords

Access to Document

Fingerprint

Cite this