Brazil and Turkey negotiated a deal with Iran. That deal was similar, but not identical, to deal(s) negotiated earlier with Iran that failed in some way. The United States responded by saying that the IAEA would have to review the agreement first. It also announced that the five veto-bearing members of the United Nations Security Council had agreed on another round of sanctions against Iran. The deal still must be reviewed, as well, by Iran's powers that be, who have undone previous deals.
I think that is accurate so far.
It is not clear to me that the announcement of support for a vote on sanctions is the same as rejecting the Iranian offer. Many are taking it that way. One argument is that Iran cannot negotiate under the threat of sanctions. I'm not sure why this is the case. Iran has been negotiating, and sanctions are in effect, which seems worse than simply a threat of sanctions.
The Iranian offer would deposit 1200 kilograms of its 3.5% enriched uranium with Turkey, and within a year would get in return fabricated fuel rods for its Teheran Research Reactor. It is also reported that Iran would continue to enrich uranium to 20%, which would no longer be necessary if it is getting fuel for the TRR. So Iran has given a bit on the timing and location of the swap, but it is holding onto a step toward weapons-grade enrichment. Iran also has about twice as much low-enriched uranium now as it did when the offer of a swap was first made. This goes back to that idea of getting the low-enriched uranium out of Iran's hands, which has clouded the negotiations from the first and provided a provocation to Iranian hard-liners.
Turkey and Brazil may or may not feel betrayed; this is one issue that I simply can't decipher from what is reported in the media. Did President Obama personally ask for or encourage their negotiations? Was there constant communication between them and the United States?
“What they wanted us to do was give the confidence to Iran to do the swap. We have done our duty,” said Davutoglu, calling the deal an important step for regional and global peace. “We were told that if Iran gives 1,200 kg without conditions, then the required atmosphere of trust would be created [to avoid sanctions]. So if we do all these things, and they still talk about sanctions … [it] will damage the psychological trust that has been created.” (source)Note that "without conditions." The Turks clearly are aware of that stipulation, which seems not to have been met.
It is hard to believe that there were no communications between Brazil, Turkey, and the United States. Some large part of such communications would have been secret, however, and we are unlikely to hear that full story any time soon.
The deal, as presented by Brazil and Turkey, seems not to have been fully approved by Iran, whatever that may take. It appears that there are factions in Iran who will not accept any deal that is acceptable to the United States, and that they sometimes have veto power. So would it make sense for the United States to accept and then have the deal slapped down again?
Here's the text of the sanctions resolution. And here are several pieces that lean more toward opinion than reporting. They contain some good points, but mostly jump much further ahead than I think is justified on the basis of the information I've seen.
New York Times editorial
M. J. Rosenberg