Electrochemical Evidence for Hemilabile Coordination of 1,3-Dimethyllumazine to [1,1 '-Bis(diorganophosphino)ferrocene]copper(I)
The complex cations [Cu(dippf)(DML)](+) ([1](+)) and [Cu(dppf)(DML)](+) ([2](+)), where dippf = 1,1'-bis(diisopropylphosphino)ferrocene, dppf = 1,1'-bis(diphenylphosphino)ferrocene, and DML = 1,3-dimethyllumazine, were prepared and crystallized as BF4- or PF6- salts. Structure determinatio...
Published in: | Organometallics |
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Main Authors: | , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2014
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Subjects: | |
Online Access: | https://doi.org/10.1021/om500039a http://hdl.handle.net/11104/0238723 |
Summary: | The complex cations [Cu(dippf)(DML)](+) ([1](+)) and [Cu(dppf)(DML)](+) ([2](+)), where dippf = 1,1'-bis(diisopropylphosphino)ferrocene, dppf = 1,1'-bis(diphenylphosphino)ferrocene, and DML = 1,3-dimethyllumazine, were prepared and crystallized as BF4- or PF6- salts. Structure determinations of the tetrafluoroborates revealed asymmetric O-4,N-5 chelation of DML to copper(I) with longer Cu-O bonds of about 2.25 angstrom. Reversible oxidation to [1](2+) and [2](2+) proceeds at the ferrocene units, while reduction leads to the neutral radical complexes [1] and [2] with the unpaired electron localized on the DML ligand. The occurrence of two voltammetric steps for the one-electron-reduction process is attributed to a two-species equilibrium caused by the hemilabile coordination of DML. Electrochemical and spectroelectrochemical measurements (UV-vis, IR) reveal increased coordination lability of the reduced complexes and their slow fragmentation. |
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