Theoretical Predictions and Single-Crystal Neutron Diffraction and Inelastic Neutron Scattering Studies on the Reaction of Dihydrogen with the Dinuclear Dinitrogen Complex of Zirconium [P₂N₂]Zr(μ-η²-N₂)Zr[P₂N₂], P₂N₂ = PhP(CH₂SiMe₂NSiMe₂CH₂)₂PPh

A single-crystal neutron diffraction analysis along with density functional calculations and incoherent inelastic neutron scattering studies has conclusively shown that the dihydrogen adduct of [P 2 N 2 ]Zr(μ-η 2 -N 2 )Zr[P 2 N 2 ] ( 1 ) (where P 2 N 2 = PhP(CH 2 SiMe 2 NSiMe 2 CH 2 ) 2 PPh) is [P 2 N 2 ]Zr(μ-η 2 -N 2 H)(μ-H)Zr[P 2 N 2 ] ( 2 ), the complex with a bridging hydride and a N−N−H moiety, and not the dihydrogen complex [P 2 N 2 ]Zr(μ-η 2 -N 2 )(μ-η 2 -H 2 )Zr[P 2 N 2 ] ( 3 ), as was proposed on the basis of X-ray crystallographic data. In addition, DFT calculations show that the reaction of 1 with both H 2 and SiH 4 is exothermic while an endothermic reaction is found for the reaction of 1 with CH 4 .