Reaction mechanism for 2 No2 molecules

[Sciencegeeknm]

On the attached file I have tried to work out the reaction pathway. The reaction given at the top is from a chemistry lecture I watched but no mechanism was given.

In the first mechanism I just reacted one of the N20 molecules with hydroxide. The hydroxide attaching to the Nitrogen and is then deprotenated  by the second OH-  I now have H20 and N03- but it doesn't explain how the second N20 molecule ends up with a second electron on the Nitrogen.

In the second mechanism (which I think is correct) the 2 N20 molecules join together to form the dimer N2O4. OH- attacks the anti bonding orbital of the  Positive Nitrogen and the 2 electrons from the N-N bond go onto the other N20 molecule. The OH attached is now deprotenated by the second OH- to leave H20,N03- and of course a lone pair on the Nitrogen.

It would be great if someone could verify the second mechanism as correct .

Regards 

Nick