10.1021/om500039a.s001
Rajkumar Jana
Rajkumar
Jana
Biprajit Sarkar
Biprajit
Sarkar
Sabine Strobel
Sabine
Strobel
Shaikh
M. Mobin
Shaikh
M.
Mobin
Wolfgang Kaim
Wolfgang
Kaim
Jan Fiedler
Jan
Fiedler
Electrochemical Evidence for Hemilabile Coordination
of 1,3-Dimethyllumazine to [1,1′-Bis(diorganophosphino)ferrocene]copper(I)
American Chemical Society
2014
voltammetric steps
BF
coordination lability
DML ligand
spectroelectrochemical measurements
Electrochemical Evidence
PF
UV
ferrocene units
2.25 Å. Reversible oxidation
Hemilabile Coordination
hemilabile coordination
Cu
complex
Structure determinations
IR
2014-09-22 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Electrochemical_Evidence_for_Hemilabile_Coordination_of_1_3_Dimethyllumazine_to_1_1_Bis_diorganophosphino_ferrocene_copper_I_/2253181
The complex cations [Cu(dippf)(DML)]<sup>+</sup> ([<b>1</b>]<sup>+</sup>) and [Cu(dppf)(DML)]<sup>+</sup> ([<b>2</b>]<sup>+</sup>), where dippf = 1,1′-bis(diisopropylphosphino)ferrocene,
dppf = 1,1′-bis(diphenylphosphino)ferrocene, and DML = 1,3-dimethyllumazine,
were prepared and crystallized as BF<sub>4</sub><sup>–</sup> or PF<sub>6</sub><sup>–</sup> salts. Structure determinations
of the tetrafluoroborates revealed asymmetric O<sup>4</sup>,N<sup>5</sup> chelation of DML to copper(I) with longer Cu–O bonds
of about 2.25 Å. Reversible oxidation to [<b>1</b>]<sup>2+</sup> and [<b>2</b>]<sup>2+</sup> proceeds at the ferrocene
units, while reduction leads to the neutral radical complexes [<b>1</b>] and [<b>2</b>] 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.