For a class of non compact Riemannian manifolds with ends (M, g), we give pseudodifferential expansions of bounded functions of the semi-classical Laplacian h 2 ∆g, h ∈ (0, 1]. We then study related L p boundedness properties and show in particular that, although ϕ(−h 2 ∆g) is not bounded on L p (M, dg) in general, it is always bounded on suitable weighted L p spaces.