Photochemical Dihydrogen Production Using an Analogue of the Active Site of [NiFe] Hydrogenase

Summers, Peter A.; Dawson, Joe; Ghiotto, Fabio; Hanson-Heine, Magnus W.D.; Vuong, Khuong Q.; Davies, E. Stephen; Sun, Xue-Z.; Besley, Nicholas A.; McMaster, Jonathan; George, Michael W.; Schr�der, Martin

Abstract

The photoproduction of dihydrogen (H2) by a low molecular weight analogue of the active site of [NiFe] hydrogenase has been investigated by the reduction of the [NiFe2] cluster, 1, by a photosensitier PS (PS = [ReCl(CO)3(bpy)] or [Ru(bpy)3][PF6]2). Reductive quenching of the 3MLCT excited state of the photosensitiser by NEt3 or N(CH2CH2OH)3 (TEOA) generates PS•−, and subsequent intermolecular electron transfer to 1 produces the reduced anionic form of 1. Time-resolved infrared spectroscopy (TRIR) has been used to probe the intermediates throughout the reduction of 1 and subsequent photocatalytic H2 production from [HTEOA][BF4], which was monitored by gas chromatography. Two structural isomers of the reduced form of 1 (1a•− and 1b•−) were detected by Fourier transform infrared spectroscopy (FTIR) in both CH3CN and DMF (dimethylformamide), while only 1a•− was detected in CH2Cl2. Structures for these intermediates are proposed from the results of density functional theory calculations and FTIR spectroscopy. 1a•− is assigned to a similar structure to 1 with six terminal carbonyl ligands, while calculations suggest that in 1b•− two of the carbonyl groups bridge the Fe centres, consistent with the peak observed at 1714 cm−1 in the FTIR spectrum for 1b•− in CH3CN, assigned to a ν(CO) stretching vibration. The formation of 1a•− and 1b•− and the production of H2 was studied in CH3CN, DMF and CH2Cl2. Although the more catalytically active species (1a•− or 1b•−) could not be determined, photocatalysis was observed only in CH3CN and DMF.

Citation

Summers, P. A., Dawson, J., Ghiotto, F., Hanson-Heine, M. W., Vuong, K. . Q., Davies, E. S., …Schröder, M. (2014). Photochemical Dihydrogen Production Using an Analogue of the Active Site of [NiFe] Hydrogenase. Inorganic Chemistry, 53(9), 4430-4439. https://doi.org/10.1021/ic500089b

• Journal Article Type: Article
• Online Publication Date: Apr 22, 2014
• Publication Date: May 5, 2014
• Deposit Date: Aug 27, 2015
• Publicly Available Date: Aug 27, 2015
• Journal: Inorganic Chemistry
• Print ISSN: 0020-1669
• Electronic ISSN: 1520-510X
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 53
• Issue: 9
• Pages: 4430-4439
• DOI: https://doi.org/10.1021/ic500089b
• Keywords: Hydrogenase, rhenium, nickel, iron, thiolate, time-resolved IR, proton reduction
• Public URL: https://nottingham-repository.worktribe.com/output/726725
• Publisher URL: http://pubs.acs.org/doi/abs/10.1021/ic500089b
• Additional Information: Received 14 January 2014; ; This document is the unedited author's version of a Submitted Work that was subsequently accepted for publication in Inorganic Chemisry, copyright © American Chemical Society after peer review. To access the final edited and published work, see http://pubs.acs.org/doi/abs/10.1021/ic500089b