Mazzotta F, Zitzer G, Speiser B, Kunz D. Electron-Deficient Imidazolium Substituted Cp Ligands and their Ru Complexes.
Chemistry 2020;
26:16291-16305. [PMID:
32996227 PMCID:
PMC7756557 DOI:
10.1002/chem.202002801]
[Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Indexed: 12/27/2022]
Abstract
The synthesis of electron-poor mono-, di- and tri(imidazolium)-substituted Cp-ylides is presented and their electronic properties are discussed based on NMR spectroscopy, X-ray structure analyses, electrochemical investigations and DFT calculations as well as by their reactivity toward [Ru(CH3 CN)3 Cp*](PF6 ). With mono- and di(imidazolium)-substituted cyclopentadienides the respective monocationic and dicationic ruthenocences are formed (X-ray), whereas tri(imidazolium) cyclopentadienides are too electron-poor to form the ruthenocenes. Cyclic voltammetric analysis of the ruthenocenes shows reversible oxidation at a potential that increases with every additional electron-withdrawing imidazolium substituent at the Cp ligand by 0.53-0.55 V in an electrolyte based on a weakly coordinating anion. A reversible oxidation can be observed for the free 1,3-disubstituted ligand as well.
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