Template-framework interactions in chiral AlPOs

We report the first computer simulation study of a chiral aluminium phosphate, GTex2, with stoichiometry [Co(tn)₃]Al₃(PO₄)₄ · 2H₂O where tn is 1,3-diaminopropane. The study is designed to elucidate the factors that stabilise these novel chiral materials. To this end, two different models of the intercalating template for the material have been considered: one in which only the shape of the template is considered, and a second in which the shape is supplemented with hydrogen bond interactions. A simple model - a large, charged sphere - was found incapable of stabilising the AlPO structure. The overlap forces that define the shape of the template were found to be essential in providing the mechanical stability of the material, but quantitative agreement with the experimental structure was only found when the hydrogen bond interactions were included. Interlayer hydrogen-bonded water was found to play an important role in bridging between the template and the inorganic layer. Calculations of the IR and inelastic neutron scattering spectra are also presented.