Deripaska is a very powerful/influential Russian oligarch with very close ties to Putin/Kremlin.
Blavatnik lives in the U.S. (NYC) and is Deripaska's business partner.
Why was House Ds Campaign Committee (DCCC) still taking Blavatnik's campaign donations after 2016 and as recent as '18?
During and since '16 Blavatnik has written multiple big dollar checks to Schumer, Gottheimer, Kander, Cory Booker, Biden, Manchin, Rahm Emanuel and of course Hillary Clinton. Also the DCCC ($64,800), another $61,300 to the DNC and $86,200 to the DSCC.
After he had maxed out to Kander he gave the Missouri Democratic State Committee $10,000 to spend on Kander's failed Senate campaign. Kathleen Rice was another D who got big multiple contributions from Blavatnik.