He has butted heads with them a few times, they kind of have a "Treaty". They are probably the only ones that can really rein him in. Fucking with their money is likely a way to do it, but even forbes is saying the current sanctions will only have a modest hit to the Russian economy. Inflation is going to happen a lot, but rich people can weather that easily enough.
I don't know, maybe Chechnya will heat up again.