I seriously doubt they would, Iran has many enemies in this world. If they launched any such weapon they would be in the cross hairs of many nations.
Then again I don't think Iran us that stupid. They are playing gotcha games, I think in order to disrupt the world to make the USA and Israel appear as the global enemy. Allowing other non combative nations to formulate fear.
It is a very smart play, if they get us believing that there are nukes over there another ten years of war depleting our resources. Its very much the same as a smaller boxer tiring out a larger stronger boxer.
I can't see any reason a nation would be so bent on suicide.