Redox‐Active N‐Heterocyclic Germylenes and Stannylenes with a Ferrocene‐1, 1′‐diyl Backbone. Issue 5 (23rd December 2016)

• Record Type: Journal Article
• Authors: Oetzel, Jan; Weyer, Nadine; Bruhn, Clemens; Leibold, Michael; Gerke, Birgit; Pöttgen, Rainer; Maier, Markus; Winter, Rainer F.; Holthausen, Max. C.; Siemeling, Ulrich
• Is Part Of: Chemistry. Volume 23:Issue 5(2017)
• Page Start: 1187
• Page End: 1199
• Publication Date: 2016-12-23
• Subjects: cyclic voltammetry -- germanium -- iron -- metallocenes -- tin; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201605074
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: We describe ferrocene‐based N‐heterocyclic germylenes and stannylenes of the type [Fe{(η 5 ‐C5 H4 )NR}2 E:] (1 R E; E=Ge, Sn; R=neopentyl (Np), mesityl (Mes), trimethylsilyl (TMS)), which constitute the first examples of redox‐functionalised N‐heterocyclic tetrylenes (NHTs). These compounds are thermally stable and were structurally characterised by means of X‐ray diffraction studies, except for the neopentyl‐substituted stannylene1 Np Sn, the decomposition of which afforded the aminoiminoferrocene [fc(NHCH2 t Bu)(N=CH t Bu)] (2 ) and the spiro tin(IV) compound (1 Np )2 Sn (3 ). DFT calculations show that the HOMO of the NHTs of our study is localised on the ferrocenylene backbone. A one‐electron oxidation process affords ions of the type1 R E +. . In contrast to the NHC system1 R C, the localised ferrocenium‐type nature of the oxidised form does not compromise the fundamental tetrylene character of1 R E +. . Abstract : Be positive, tetrylene ! N‐heterocyclic germylenes and stannylenes with a ferrocenylene backbone are described, which are the first examples of redox‐functionalised N‐heterocyclic terylenes (see figure). Consistent with the strongly localised nature of the HOMO, the oxidation process is ferrocene based. The ferrocenium‐type nature of the resulting cation does not compromise the fundamental tetrylene character of these species, thus opening the door to a reversible umpolung of their electronic profile by redox switching.