A well-defined mesoporous amine silica surface via a selective treatment of SBA-15 with ammonia

2D double-quantum (1)H-(1)H NMR unambiguously shows that the "isolated" ≡Si-OH surface silanols of dehydroxylated SBA-15 are converted upon treatment with ammonia into single silylamine surface site ≡Si-NH(2). The "gem" di-silanols (=Si(OH)(2)) remain intact. Treatment using HMDS produces (=Si(OSiMe(3))(2)) but leaves ≡Si-NH(2) untouched. The resulting surface is hydrophobic and stable.