Here's the easy way to beat the first Deus Ex boss straight from the Future Press guide:
Throw grenades at his feet to stun him as Wombat suggested, but then follow up by throwing the items in the room that can explode at him, and in some instances, shoot them so they explode on him. The red, explosive barrel in the back of the room takes off about 50-75% of his health by itself.
The funny moment was I had him nearly dead apparently and I was nearly dead also and he accidentally shot the fire extinguisher near him trying to shoot me and that was enough damage to kill him.
And Wombat, I figured you'd loved the inventory system since it was from RE 4.