Read the buyer's/renter's agreement with the agent.
The answer--contained for certain in the agreement--is "probably yes."
You say there was never an executed lease. OK. So? Read the signed agreement to see what the proposed tenant agreed to.
The question isn't (here) whether there was a "deal" in the form of a lease. The question is whether there was a "deal" in the form of an agreement where the real estate agent was owed money if he/she performed certain services.