Excess proton hydrate structures with large proton polarizability in the channel of trioxaalkyl phosphate

Complexes of tributyl phosphate (TBPO) and tris(10-chloro-3,6,9-trioxadecyl) phosphate (TODPO) with HAuCl4 and their hydrates with various amounts of water were studied by FT-IR spectroscopy. TBPO with HAuCl4 forms homoconjugated PO+H···OP ⇌ PO···H+OP hydrogen bonds with large proton polarizability. In hydrates of homoconjugated PO+H···OP ⇌ PO···H+OP complexes, H5O2+ is formed with a hydrogen bond having large proton polarizability. In the 1:1 mixture no H3O+, but both H5O2+ and PO+H···OP ⇌ PO···H+OP homoconjugated bonds are present in the a 1:1 ratio. In the protonated and hydrated mixtures of TODPO no homoconjugated PO+H···OP ⇌ PO···H+OP hydrogen bonds and no H5O2+ species are found. In these complexes the proton and water molecules are present in the channels which show large proton polarizability. The behaviour of these protonated and hydrated channels is discussed with respect to the behaviour of the gramicidin channel.