1618657-63-8Relevant academic research and scientific papers
Fine-tuning the energy barrier for metal-mediated dinitrogen N≡N bond cleavage
Keane, Andrew J.,Yonke, Brendan L.,Hirotsu, Masakazu,Zavalij, Peter Y.,Sita, Lawrence R.
supporting information, p. 9906 - 9909 (2014/08/05)
Experimental data support a mechanism for N≡N bond cleavage within a series of group 5 bimetallic dinitrogen complexes of general formula, {Cp*M[N(iPr)C(R)N(iPr)]}2(μ-N 2) (Cp* = η5-C5Me5) (M = Nb, Ta), that proceeds in solution through an intramolecular end-on-bridged (μ- η1:η1-N 2) to side-on-bridged (μ- η2: η2-N2) isomerization process to quantitatively provide the corresponding bimetallic bis(μ-nitrido) complexes, {Cp*M[N( iPr)C(R)N(iPr)](μ-N)}2. It is further demonstrated that subtle changes in the steric and electronic features of the distal R-substituent, where R = Me, Ph and NMe2, can serve to modulate the magnitude of the free energy barrier height for N≡N bond cleavage as assessed by kinetic studies and experimentally derived activation parameters. The origin of the contrasting kinetic stability of the first-row congener, {Cp*V[N(iPr)C(Me)N(iPr)]} 2(μ- η1:η1-N2) toward N≡N bond cleavage is rationalized in terms of a ground-state electronic structure that favors a significantly less-reduced μ-N2 fragment.
