University of Oulu

Zandria Lamprecht, Frederick P. Malan, David C. Liles, Simon Lotz, Daniela I. Bezuidenhout, Synthesis and structure of annulated dithieno[2,3-b;3ʹ,2ʹ-d]thienyl- and ring-opened 3,3ʹ-bithienyl Fischer carbene complexes, Journal of Organometallic Chemistry, Volume 925, 2020, 121466, ISSN 0022-328X,

Synthesis and structure of annulated dithieno[2,3-b;3′,2′-d]thienyl- and ring-opened 3,3′-bithienyl Fischer carbene complexes

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Author: Lamprecht, Zandria1; Malan, Frederick P.1; Liles, David C.1;
Organizations: 1Department of Chemistry, University of Pretoria, Private Bag X20, Hatfield, 0028, Pretoria, South Africa
2Laboratory of Inorganic Chemistry, Environmental and Chemical Engineering, University of Oulu, P. O. Box 3000, 90014, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.8 MB)
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Language: English
Published: Elsevier, 2020
Publish Date: 2020-09-07


Nucleophilic attack on the central sulphur of dithieno[2,3-b;3′,2′-d]thiophene (DTT) by n-BuLi opens the central thiophene ring and afforded, after subsequent reaction with Cr(CO)₆ and alkylation with [Et₃O][BF₄], a series of mono- and biscarbene complexes containing a 3,3′-dithienyl backbone with a SBu substituent. Repeating the reaction with diisopropylamine as the nucleophile, leads to a dihydrodesulphurization reaction with ring-opening of the central thiophene ring of DTT and elimination of the sulphur atom. Subsequent reaction with n-BuLi or LDA, Cr(CO)₆ and [Et₃O][BF₄] afforded 3,3′-dithienyl mono- and biscarbene complexes. In both instances α,α′-dithienothiophene biscarbene complex was observed spectroscopically but not isolated. By using α,α′-dibromodithieno[2,3-b;3′,2′]thiophene as substrate, improved yields of the targeted mono- and biscarbene complexes of [2,3-b;3′,2′-d]-DTT (M=Cr, W) could be obtained. The biscarbene complexes were unstable in the reaction mixture but in the case of tungsten could be isolated after in situ aminolysis with dimethylamine. The use of KHMDS as base converted Cr(CO)₆ to K[Cr(CO)₅(CN)] and after reaction with DTT and subsequent alkylation with [Et₃O][BF₄], afforded the chromium tetracarbonyl carbene complex of DTT.

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Series: Journal of organometallic chemistry
ISSN: 0022-328X
ISSN-E: 1872-8561
ISSN-L: 0022-328X
Volume: 925
Article number: 121466
DOI: 10.1016/j.jorganchem.2020.121466
Type of Publication: A1 Journal article – refereed
Field of Science: 116 Chemical sciences
215 Chemical engineering
Funding: The authors gratefully acknowledge the National Research Foundation, South Africa (NRF 105740; NRF 105529 NRF 87788 and NRF 9772) and Sasol Technology R&D Pty. Ltd. (South Africa) for financial support.
Copyright information: © 2020 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license. ( )