It's becomingeven more obvious that President Trump is not about service to the nation, but...
about increasing Trump profits and visibility.
After his last string of bankruptcies and failures, his handlers showed him the better way of not buying or building buildings with his name on them (which he was really not that good at, and which tended to fail) but to use his true talents of Barnum bluster and bragging to sell his name to be put on the buildings of others.
Now that he is President, he has the biggest selling point of all-- "Pay me, the US President, to put my name on your building."
There is that implicit threat that the President could look unkindly on someone who didn't take such an offer that couldn't be refused. There is also the thought of buying his name as a "gift" that wouldn't really be a bribe-- but what else would it be?
The "emoluments" language has been mentioned, and here is the law on Presidential gifts:
https://fas.org/sgp/crs/misc/R42662.pdf