Jump to main content
Jump to site search
Access to RSC content Close the message box

Continue to access RSC content when you are not at your institution. Follow our step-by-step guide.


Issue 44, 2015
Previous Article Next Article

Synthesis and properties of mono- and dimetal Fischer multicarbene complexes derived from thiophene and thieno[2,3-b]thiophene

Author affiliations

Abstract

Access to multicarbene complexes of a fused thienothiophene substrate was obtained by the use of the tetrabrominated thieno[2,3-b]thiophene precursor in a lithium–bromide exchange reaction, followed by nucleophilic attack on metal hexacarbonyls (M = Cr, W). Subsequent alkylation afforded unique triscarbene complexes [M(CO)4{{C(OEt)}2C6H1S2C(OEt)}M(CO)5] (M = Cr 12, W 13) featuring three non-equivalent carbene ligands on a single thiophene linker, as well as the bischelated tetracarbene complexes [M(CO)4{{C(OEt)}2C6S2{C(OEt)}2}M(CO)4] (M = Cr 14, W 15). The triscarbene complexes 12 and 13 are the first examples of multi-alkoxycarbene complexes featuring three non-equivalent carbene ligands. The reaction also afforded the chelated mononuclear biscarbene complexes [M(CO)4{C(OEt)}2C6H2S2] (M = Cr 10, W 11) in low yields. Similarly, employing tetrabromothiophene as precursor yielded the mononuclear chelate biscarbene complexes [M(CO)4{C(OEt)}2C4H2S] (M = Cr 6, W 7) and the dinuclear tetracarbene complexes [M(CO)4{{C(OEt)}2C4S{C(OEt)}2}M(CO)4] (M = Cr 8, W 9). Modification of the classic Fischer carbene synthetic methodology to a process of stepwise additions of lithiating agent and metal carbonyls to thieno[2,3-b]thiophene, facilitates the formation of the mixed metal biscarbene complex [W(CO)5C(OEt){C6H2S2}C(OEt)Cr(CO)5] 5, as analogue of the homonuclear biscarbene complexes [M(CO)5C(OEt){C6H2S2}C(OEt)M(CO)5], (M = Cr 3, W 4). The monocarbene complexes [M(CO)5{C(OEt)C6H3S2}], (M = Cr 1, W 2) were also obtained in high yields, and the molecular structures of the tungsten complexes, with the exception of 9 and 11, were confirmed by single crystal X-ray diffraction studies.

Graphical abstract: Synthesis and properties of mono- and dimetal Fischer multicarbene complexes derived from thiophene and thieno[2,3-b]thiophene

Back to tab navigation

Supplementary files

Article information


Submitted
11 Sep 2015
Accepted
09 Oct 2015
First published
13 Oct 2015

Dalton Trans., 2015,44, 19218-19231
Article type
Paper
Author version available

Synthesis and properties of mono- and dimetal Fischer multicarbene complexes derived from thiophene and thieno[2,3-b]thiophene

Z. Lamprecht, N. A. van Jaarsveld, D. I. Bezuidenhout, D. C. Liles and S. Lotz, Dalton Trans., 2015, 44, 19218
DOI: 10.1039/C5DT03555D

Social activity

Search articles by author

Spotlight

Advertisements