54985-05-6Relevant academic research and scientific papers
Oxidation of the carbonylbis(1,2-bis(dipbenylphosphino)ethane)iridium(I) cation. Preparation and characterization of a series of iridium(III) carbonyl dications
Lilga, Michael A.,Ibers, James A.
, p. 3538 - 3543 (2008/10/08)
Oxidation of Ir(CO)(dppe)2+ with halogens affords cis-IrX(CO)(dppe)22+ (X = Cl, Br) while oxidation with HBF4 affords cis-IrH(CO)(dppe)22+. The species trans-IrX(CO)(dppe)22+ (X = Cl, Br) are prepared by the oxidation of Ir(CO)(dppe)2+ with nitrosonium ion in the presence of Cl- or Br-. The complex trans-IrH(CO)(dppe)22+ is most conveniently prepared by protonation of [Ir(dppe)2]BF4 with HBF4·Et2O to afford the intermediate IrH(dppe)22+, followed by CO addition. In contrast, both cis- and trans-IrCl(CO)(dppe)22+ species are formed by the electrochemical oxidation of Ir(CO)(dppe)2+ in chloride media. The trans isomer is reduced at a more negative potential and is thus thermodynamically the more stable. Reversible deprotonation of cis-[IrH(CO)(dppe)2][BF4]2 by chloride implies that the acidity of this compound is of the order of that of HCl, unusually strong for a third-row transition-metal hydrido complex.
