Like when Obama called Putin to congratulate him on his victory?
Or do you mean when Obama said about Putin, before their Beluga Breakfast meeting in Russia: “I am aware of not only the extraordinary work that you've done on behalf of the Russian people in your previous role as prime minis-, uh, as president, but in your current role as prime minister,"
Or maybe you mean when he praised Putin with:
Russia was a help on this. I’ll be honest with you. I was not sure given the strong differences we are having with Russia right now around Ukraine, whether this would sustain itself. Putin and the Russian government compartmentalized on this in a way that surprised me, and we would have not achieved this agreement had it not been for Russia’s willingness to stick with us and the other P5-plus members in insisting on a strong deal.”