This story is part of a recurring pro-Kremlin disinformation narrative that Western sanctions in general and Western sanctions against Russia in particular are illegal, unjust and ineffective.
Sanctions against Turkey were applied under the Countering America's Adversaries Through Sanctions Act (CAATSA) which specifically mentions Russia under Title II (Sanctions with Respect to the Russian Federation and Combatting Terrorism and Illicit Financing).
Additionally, on September 20 2018, President Donald Trump delegated the authority to implement the actions required in CAATSA to the Secretary of State and Secretary of the Treasury in Executive Order (EO) 13849. Under this decision, the US Treasury sanctioned officials and targeted entities supporting Russia's occupation of Crimea.
The sanctions against Turkey were imposed against the Presidency of Defense Industries (SSB) and four of its senior officials as Ankara decided to procure the S-400 surface-to-air antimissile system from Russia. The United States had repeatedly warned Turkey that the Russian system constitutes a risk both for the interoperability of NATO defence systems but also for the security F-35 aircrafts. Furthermore, the U.S. has already informally sanctioned Turkey by suspending its participation in the F-35 programme and maintaining control of F-35 air systems for which Ankara has already paid.
Further reading on the Russian narrative about ineffective Western sanctions can be consulted in this article by StopFake. More cases related to sanctions are available here.