Activation and Coordination of Ammonia at [Cp*Ir(H) 2 ]: NMR and Matrix Isolation Studies

1 H NMR exchange spectroscopy of a reaction mixture of [Cp*Ir(H) 4 ] ( 1 ; Cp*=1,2,3,4,5‐pentamethylcyclopentadienyl) and ammonia suggests an exchange of hydrogen atoms between the hydrido ligands and ammonia. Treatment of 1 with ND 3 led to an H/D exchange between ND 3 and the hydrido ligands of 1 . Subsequent studies showed that photolysis of 1 isolated in frozen argon matrices leads to the formation of the iridium compounds [Cp*Ir(H) 2 ] ( 2 ) and [Cp*Ir(H) 3 ] ( 4 ), as it was confirmed by IR spectroscopy. In the presence of water the aqua complex [Cp*Ir(H) 2 (OH 2 )] ( 3 ) was generated simultaneously. Accordingly, photolysis of 1 in an argon matrix doped with ammonia gave rise to the ammine complex [Cp*Ir(H) 2 (NH 3 )] ( 5 ). IR assignments were supported by calculations of the gas‐phase IR spectra of 1 – 5 by DFT methods.