Details

Autor(en) / Beteiligte

• Pons, Vincent
• Heinekey, D. Michael

Titel

An Elongated Dihydrogen Complex of Iridium

Ist Teil von

• Journal of the American Chemical Society, 2003-07, Vol.125 (28), p.8428-8429

Ort / Verlag

Washington, DC: American Chemical Society

Erscheinungsjahr

2003

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Reaction of [Cp*Ir(dmpm)Cl]Cl with [Et3Si]B(ArF)4 (dmpm = bisdimethyl-phosphinomethane; ArF = C6F5) under hydrogen gas affords the dicationic complex [Cp*Ir(dmpm)H2]2+ (1), which is readily deprotonated by weak bases to give [Cp*Ir(dmpm)H]+. Complex 1 exists as a mixture of two isomers (97:3). On the basis of the magnitude of 2 J H - P couplings and T 1 measurements, a cis-dihydride or dihydrogen complex structure is suggested for the predominant isomer 1- cis ( 2 J H - P = 6 Hz), with the minor isomer assigned a transoid structure 1- trans ( 2 J H - P = 20 Hz). When the preparative reaction is carried out with HD gas, the resonance in the 1H NMR spectrum assigned to 1- cis- d 1 exhibits J H - D = 9.0 Hz. The observed values of 1 J H - D vary significantly with temperature, increasing from 7.0 Hz at 223K to 9.0 Hz at 300 K. The observed chemical shift of 1- cis- d 1 also varies significantly with temperature. These observations are interpreted in terms of a dynamic equilibrium between a cis-dihydride and a dihydrogen complex.