This Ukraine / Crimea crisis is most likely to disrupt not only the European M&A sector but also the global one. This crisis already affected global markets and most of the Russian businesses and banks are withdrawing and moving funds back to Russia as they are afraid of possible sanctions from EU and US.
Short term .. probably only Russian companies involved will be affected but problem is that in a longer term the region will have a big percentage of investors who will lack the confidence to pursue existing plans.
Russia represents around 19% of all international M&A value for 2013 and an impact caused by possible economic sanctions will be seen for sure in the region in the coming months as this represents a huge value of the total market.