Dinitrogen activation by zirconium dimer loaded C60

Dinitrogen activation plays an important role in the production of many essential nitrogen based compounds needed for all life. Using density functional theory together with dispersion correction (DFT+D), the activation of molecular nitrogen with a gas phase Zr dimer and a Zr dimer loaded C60 is investigated. The present calculations show that the optimised trans-Zr2N2 configuration is planar but this configuration exhibits a butterfly shape when it is supported by C60. Furthermore, it is shown that the activation of dinitrogen is facilitated by the Zr dimer stabilized by C60. Additional calculations are carried out to look at the products of the reactions with H2 and a catalytic cycle for the reduction of N2 to NH3 is constructed. Reaction of two molecules of H2 with Zr2N2 molecule loaded C60 is exothermic while reaction of only one molecule of H2 with free Zr2N2 molecule is exothermic again highlighting the importance of stabilization with C60.