Ligand-centred reactivity of bis(picolyl)amine iridium: sequential deprotonation, oxidation and oxygenation of a "non-innocent" ligand.
Treatment of [Ir(bpa)(cod)](+) complex [1](+) with a strong base (e.g., tBuO(-)) led to unexpected double deprotonation to form the anionic [Ir(bpa-2H)(cod)](-) species [3](-), via the mono-deprotonated neutral amido complex [Ir(bpa-H)(cod)] as an isolable intermediate. A certain degree of aromaticity of the obtained metal-chelate ring may explain the favourable double deprotonation. The rhodium analogue [4](-) was prepared in situ. The new species [M(bpa-2H)(cod)](-) (M = Rh, Ir) are best described as two-electron reduced analogues of the cationic imine complexes [M(I)(cod)(Py-CH(2)-N=CH-Py)](+). One-electron oxidation of [3](-) and [4](-) produced the ligand radical complexes [3](*) and [4](*). Oxygenation of [3](-) with O(2) gave the neutral carboxamido complex [Ir(cod)(py-CH(2)-N-CO-py)] via the ligand radical complex [3](*) as a detectable intermediate.
Instituto de Ciencia de materiales de Aragón, CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50007 Zaragoza, Spain. ctejel@unizar.es
Cristina
C
Tejel
M Pilar
MP
del Río
Miguel A
MA
Ciriano
Eduard J
EJ
Reijerse
Frantisek
F
Hartl
Stanislav
S
Zális
Dennis G H
DG
Hetterscheid
Nearchos
N
Tsichlis i Spithas
Bas
B
de Bruin
D008024:Ligands; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D011522:Protons; D011789:Quantum Theory; D013057:Spectrum Analysis; D013997:Time Factors
D008024:Ligands; D009942:Organometallic Compounds; D011522:Protons; C546560:bis(picolyl)amine iridium; D010100:Oxygen