Ambassador Susan Rice wore purple for her remarks on Iran to the Security Council last week. It's worth watching the whole video for two different angles on her outfit:
These colors work for her, as does the round scoop neck which is echoed by the shape of her necklace. My only concern here are her earrings. The dangling shape in this case is distracting, and the close match with her necklace makes for too much of the same design motif within a close space.
Please note that I did not deride her for being "matchy." There is a strong wave in the fashion press right now against "matching" but there's nothing wrong with it when done correctly. You just need to recognize when you have too much of a good thing.