Mechanistic studies on the interaction of [(kappa3-P,P,P-NP3)IrH3] [NP3 = N(CH2CH2PPh2)3] with HBF4 and fluorinated alcohols by combined NMR, IR, and DFT techniques.
The novel iridium(III) hydride [(kappa(3)-P,P,P-NP(3))IrH(3)] [NP(3) = N(CH(2)CH(2)PPh(2))(3)] was synthesized and characterized by spectroscopic methods and X-ray crystallography. Its reactivity with strong (HBF(4)) and medium-strength [the fluorinated alcohols 1,1,1-trifluoroethanol (TFE) and 1,1,1,3,3,3-hexafluoroisopropanol (HFIP)] proton donors was investigated through low-temperature IR and multinuclear NMR spectroscopy. In the case of the weak acid TFE, the only species observed in the 190-298 K temperature range was the dihydrogen-bonded adduct between the hydride and the alcohol, while with the stronger acid HBF(4), the proton transfer was complete, giving rise to a new intermediate [(kappa(3)-P,P,P-NP(3))IrH(4)](+). With a medium-strength acid like HFIP, two different sets of signals for the intermediate species were observed besides dihydrogen bond formation. In all cases, the final reaction product at ambient temperature was found to be the stable dihydride [(kappa(4)-NP(3))IrH(2)](+), after slow molecular dihydrogen release. The nature of the short-living species was investigated with the help of density functional theory calculations at the M05-2X//6-31++G(df,pd) level of theory.
Rossin
Andrea
A
Instituto di Chimica dei Composti Organometallici (ICCOM-CNR), Via Madonna del Piano 10, 50019 Sesto Fiorentino (Firenze), Italy.
Gutsul
Evgenii I
EI
Belkova
Natalia V
NV
Epstein
Lina M
LM
Gonsalvi
Luca
L
Lledós
Agustí
A
Lyssenko
Konstantin A
KA
Peruzzini
Maurizio
M
Shubina
Elena S
ES
Zanobini
Fabrizio
F