In the first part of an exclusive two-part interview, Iranian Foreign Minister Mohammad Javad Zarif refutes the idea that sanctions against Iran helped bring the country back to the negotiating table over its nuclear ambitions. "If the U.S. government wanted to antagonize the Iranian people... then the sanctions have succeeded," he says. The first part of the interview airs on PBS on April 28, 2015. For more, visit www.charlierose.com