How do we represent the reduction of dinitrogen?
The reaction is thermodynamically downhill, i.e. it is exothermic and releases energy. Of course the reaction has a very high activation energy, and requires effective catalysis to reduce this energy of activation. There are some good examples of in vitro dinitrogen activation, i.e. experiments at single metal centres, which can be conveniently studied.
Why should the reaction require high energy of activation?