What were the details of the Louisiana Purchase, and why was Jefferson conflicted about the deal?

Details of Louisiana Purchase: United States purchase 827,000 square miles of land west of the Mississippi River which previously belonged to the French Empire for $15 million.

At that time, Jefferson's had two main concerns about the deal :

- The region surrounding the purchased territory was shared between Spain and Great Britain. He's worried that a potential conflict might occurred with them because of the purchase

- The constitution did not directly stated that the president has the power to purchase the territory belonged to another countries.

which sentences ? that question is incomplete