Iran could teach Russia how to evade sanctions and 'money launder', according to an opinion piece in the WSJ (Dubowitz and Zweig)
Of Tehran could serve as Russia's broker, taking a cut of the "illicit" trade it facilitates on Russia's behalf.
Iran has a 'money laundering' architecture, a system they could make available to others.
US/West kicked Iran of Swift, reduced their oil sales from 2.5b barrels to a few hundred thousand. So Iran has dealt with harsher sanctions than Russia (which still sells gas to Europe and has some institutions on Swift reportedly).