A series of new four-coordinate Ir(I) complexes IrCl(N2C5X4)(PR3)2 (X = Cl, Br; R = phenyl, p-fluorophenyl, p-tolyl) has been prepared by allowing the neutral diazo molecule to react with “IrCl(PR3)2”. The complexes have been characterized spectroscopically: Ir is in a square-planar environment with trans phosphine ligands and with the N2C5X4 ligand attached in the singly bent fashion through the terminal nitrogen atom. The complex IrCl(N2C5Cl4)(PPh3)2 reacts with PMe3, PMe2Ph, PMePh2, t-BuNC, and NO+ to form the respective five-coordinate complexes. In these complexes, which have been characterized by the usual analytical and spectroscopic techniques, the N2C5C14 molecule remains coordinated in an r)3fashion. The complex IrCl(N2C5Cl4)(PPh3)2 reacts with HC1 to form the six-coordinate Ir(III) oxidative addition product. Reaction of this complex, prepared in situ, with A-methyl-N-nitroso-p-toluenesulfonamide yields the six-coordinate nitrosyl/diazo complex IrCl2(N2C5Cl4)(NO)(PPh3)2. An orthometalated hydrido species IrHCl(2, 7-Br2N2C13H5)(PPh3)2 is formed in the reaction of IrCl(N2)(PPh3)2 with 2, 7-dibromo-9-diazofluorene in the presence of ethanol. The analogous four-coordinate Rh systems, RhCl(N2C5X4)(PR3)2 (X = Cl, Br; R = Ph, i-Pr, p-FC6H4, Cy, t-Bu), were generated as transient intermediates but could not be isolated even at low temperature. The significant differences in the chemistries of IrCl(N2C5Cl4)(PPh3)2 and IrCl(N2Ph)(PPh3)2 + are contrasted.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry