The article suggests that financing companies used by Trump were "laundering" "dirty" money from eastern Europe, but that's as far as the allegations go. They don't even define how the money was "dirty" or what money was being "laundered."
When I think of money laundering, I think of drug money or illegal bookmaking money being run through a legitimate business to give it "legal" status. Or, I think of taxable funds being improperly made into non-taxable funds.
I don't get from this article that Trump was laundering money. I don't get from this article that Trump was trading future access for quick cash. I don't get from this article that Trump is being blackmailed over past involvements from his troubled projects. I don't get from this article that Trump was planning a future Presidential run when he was involved in financing these projects. I don't get from this article that Trump needed dirty money to finance his 2016 campaign.
Therefore, I'm not getting the collusion angle for Mueller to be investigating. Associating with questionable people is not enough to accuse someone. That's not to say that Mueller isn't expanding his charter to look for any infractions of any kind, but in my opinion, he's straying quite far from the idea that Trump colluded with Russians to steal the election from Hillary Clinton by chasing these leads.
-PJ