How can I regulate 7.2V to 5V?
why would you do that with a Negative voltage regulator when it says in the datasheet: DC input voltage: - 5 to - 18 V, and it already told you its a negative one in the second line of the datasheet?
7805 should work, it has a voltage dropout of 2V, so if u get below 7V at the input it wont be able to regulate to 5V.