Issue 32, 2019

Sulphur–sulphur, sulphur–selenium, selenium–selenium and selenium–carbon bond activation using Fe3(CO)12: an unexpected formation of an Fe2(CO)6 complex containing a μ23-C,O,Se-ligand

Abstract

Three diiron hexacarbonyl complexes containing dithiolato (5), diselenolato (6), and selenolato-thiolato ligands (7), respectively, have been prepared as [FeFe]-hydrogenase mimics. Treatment of Fe3(CO)12 with one equivalent of the corresponding 5-membered heterocycles 1, 3 and 4 in toluene at reflux afforded the corresponding complexes 5–7. The reaction of 5,5-bis(bromomethyl)-2,2-dimethyl-1,3-dioxane with in situ generated Na2Se2 results in the formation of 8,8-dimethyl-7,9-dioxa-2,3-diselenaspiro[4.5]decane (1) and traces of 7,7-dimethyl-6,8-dioxa-2-selenaspiro[3.4]nonane (2). Alternatively, 5,5-bis(bromomethyl)-2,2-dimethyl-1,3-dioxane reacts with in situ generated Na2Se yielding compound 2 in 26% yield. When Fe3(CO)12 reacts under reflux with the selenaspiro compound 2 in toluene, the unique diiron complex, [Fe2(CO)623-Se,C,O-SeCH2C7H12O2}] (8), is obtained as a result of an initial selenium–carbon bond activation. Compounds 5, 6, 7, and 8 were characterized by IR, 1H, 13C{1H}, and 77Se{1H} NMR spectroscopy, mass spectrometry, elemental analysis, and X-ray single-crystal structure analysis. The chiral complex 8 shows a coordination of the O atom at the dioxane ring to one Fe atom and the O–CH carbanionic group to the other Fe atom. Furthermore, we investigated the redox properties and the catalytic behaviour of complexes 5–8 in the presence of AcOH as a source of protons. The reduction of complexes 5–7 is accompanied by a chemical process resulting in an overall two-electron transfer at their primary reduction wave. This observation is consistent with an ECE reduction (E = electrochemical process, C = chemical process), while each reduction event in the case of complex 8 involves simple transfer of one electron. Moreover, high level DFT calculations were performed on neutral 8 and its reduction products 8 and 82−.

Graphical abstract: Sulphur–sulphur, sulphur–selenium, selenium–selenium and selenium–carbon bond activation using Fe3(CO)12: an unexpected formation of an Fe2(CO)6 complex containing a μ2,κ3-C,O,Se-ligand

Supplementary files

Article information

Article type
Paper
Submitted
21 မေ 2019
Accepted
01 ဇူ 2019
First published
02 ဇူ 2019

New J. Chem., 2019,43, 12580-12593

Sulphur–sulphur, sulphur–selenium, selenium–selenium and selenium–carbon bond activation using Fe3(CO)12: an unexpected formation of an Fe2(CO)6 complex containing a μ23-C,O,Se-ligand

R. Trautwein, H. Abul-Futouh, H. Görls, W. Imhof, L. R. Almazahreh and W. Weigand, New J. Chem., 2019, 43, 12580 DOI: 10.1039/C9NJ02642H

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