In this work we present an exhaustive, experimental and theoretical, investigation on the structural, vibrational, electronic, and energetic properties of TS-1 catalyst. The perturbation induced by adsorption of water and ammonia ligands, which represent two key molecules in the industrial processes catalyzed by TS-1, is also discussed in great detail on both experimental and computational ground. Theory and experiments allow us to present a picture able to describe in a satisfactory way the interaction of both molecules with Ti(IV) sites and with the hosting siliceous matrix.