Heterocyclic-based ferrocenyl carboselenolates: Synthesis, solid-state structure and electrochemical investigations

Deeb Taher, Firas F. Awwadi, J. Matthaeus Speck, Marcus Korb, Dieter Schaarschmidt, Saddam Weheabby, Almeqdad Y. Habashneh, Mousa Al-Noaimi, Mohammad El-Khateeb, Sultan T. Abu-Orabi, Heinrich Lang

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Abstract

Treatment of two equiv. of [Fe(eta(5)-C5H5)(eta(5)-C5H4SeSiMe3)] (1) with one equiv. of 2,5-(ClC(O))(2)-(C4H2X)-C-c (2) produced the corresponding ferrocenyl carboselenolates 2,5-[(FcSeC(O))(2)-(C4H2X)-C-c] (3) ([Fc = Fe(eta(5)-C5H5)(eta(5)-C5H4)]; a, X = O; b, X = NMe; c, X = Se). On the other hand, [Fe(eta 5-C5H4SiMe3)(2)] (4) reacted with 2-ClC(O)-cC4H3X (5) in a 1: 2 M ratio to give [Fe(eta(5)-C5H4SeC(O)-2-(C4H3X)-C-c)(2)] (6) (a, X = O; b, X = NMe; c, X = Se). Compounds 3a-c and 6a-c have been characterized by elemental analysis, NMR (H-1, C-13{H-1}, Se-77{H-1}) and IR spectroscopy. The structures of 3a-c and 6a in the solid state were determined by single crystal X-ray structure analysis. The cyclic voltammetry measurements for 3a-c and 6aec show reversible electrochemical processes (Fc/Fc(+)) between 135 and 170 mV for 3a-c and between 135 and 220 mV for 6a-c using [NnBu(4)][B(C6F5)(4)] as the supporting electrolyte. It was found that the furyl-and selenophyl-functionalized systems resulted in a significantly higher Fc/Fc(+) redox potential (E-0') as observed for the more electron-rich pyrrolyl derivatives. The Fc/Fc(+) redox potential (E-0') for 6a-c is significantly higher than the one for 3a-c, due to the presence of two selenoester moieties attached to the ferrocene in 6a-c. Spectroelectrochemical UVeVis/NIR studies of 3b reveal that the two Fc/Fc(+) centers in the mixed-valent species are not electronically intercommunicating via the heterocyclic bridge. (C) 2017 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)55-62
Number of pages8
JournalJournal of Organometallic Chemistry
Volume845
DOIs
Publication statusPublished - 15 Sep 2017
Externally publishedYes

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