Anodic Electrochemistry of Free and Coordinated 1,1‘-Bis(di-tert-butylphosphino)ferrocene
Abstract
The electrochemistry of 1,1‘-bis(di-tert-butylphosphino)ferrocene (dtbpf) was examined in methylene chloride with tetrabutylammonium hexafluorophosphate as the supporting electrolyte. Two new complexes in which dtbpf was bound to a transition metal were prepared and characterized. The two new complexes as well as two previously reported complexes were analyzed by cyclic voltammetry. In addition, the chalcogenids, dtbpfS2 and dtbpfSe2, were prepared and characterized by NMR and the structure of dtbpfSe2 was determined. The oxidation of dtbpfS2 is a simple one-electron process due to the presence of the iron center. In contrast, the oxidation of dtbpfSe2 is electrochemically irreversible and appears to proceed by an EE mechanism. Chemical oxidation of dtbpfSe2 resulted in the formation of [dtbpfSe2][BF4]2, in which a Se?Se bond formed. This compound was characterized by 31P NMR and X-ray crystallography. A detailed analysis of the electrochemistry suggests that the oxidation of dtbpfSe2 occurs by two separate one-electron processes. In addition, formation of the Se?Se bond was reversible.