Dinitrogen Activation by Dihydrogen and a PNP-Ligated Titanium Complex.

The hydrogenolysis of the PNP-ligated titanium dialkyl complex {(PNP)Ti(CH2SiMe3)2} (1, PNP = N(C6H3-2-PiPr2-4-CH3)2) with H2 (1 atm) in the presence of N2 (1 atm) afforded a binuclear titanium side-on/end-on dinitrogen complex {[(PNP)Ti]2(μ2,η1,η2-N2)(μ2-H)2} (2) at room temperature, which upon heating at 60 °C with H2 gave a μ2-imido/μ2-nitrido/hydrido complex {[(PNP)Ti]2(μ2-NH)(μ2-N)H} (3) through the cleavage and partial hydrogenation of the N2 unit. The mechanistic aspects of the hydrogenation of the N2 unit in 2 with H2 have been elucidated by the density functional theory calculations.