Intercalates of Strontium Phenylphosphonate with Alcohols - Structure Analysis by Experimental and Molecular Modeling Methods
Abstract
Alcohol intercalated strontium phenylphosphonates were prepared by the addition of alcohols to an aqueous solution of strontium phenylphosphonate (SrPhP). These intercalates are unstable and de-intercalate spontaneously at ambient conditions.
For the complete elucidation of their structure, a combination of a single-crystal X-ray diffraction and molecular modeling was used. The structure of the host layers in methanol (SrPhP center dot MeOH) and ethanol (SrPhP center dot EtOH) intercalates is composed of strontium atoms, which are eight-coordinate by oxygen atoms of the phosphonato groups and of water molecules.
The structures of SrPhP center dot MeOH and SrPhP center dot EtOH differ in the orientation of the phenyl rings. The alcohol molecules reside in the cavities formed by the phenyl rings and are coordinated to the Sr atoms of the host layer through their oxygen atoms.
On the basis of the structure of SrPhP center dot EtOH, the structures of propanol and butanol intercalates and of strontium phenylphosphonate dihydrate (SrPhP center dot 2H(2)O) were modeled. The proposed model of SrPhP center dot 2H(2)O, which features three kinds of water molecules, elucidates the temperature-and humidity-dependent behavior of the compound.