Interaction in molecular crystals, 157 [1,2]. Mixed crystal growth and structure determinations of tetrakis(3,4-dimethylphenyl)-imidodiphosphate salts with alkali cation ratios K circle plus/Rb circle plus(1 : 5) and Rb circle plus/Cs circle plus(1 : 1)

Mixed crystals of tetrakis(3,4-dimethylphenyl) imidodiphosphate salts with alkalication ratios K+/Rb+ (1:5) and Rb+/Cs+ (1:1), (1:3) as well as (3:1) have been grown by suspending finely ground stoichiometric mixtures of alka li carbonates in toluene solutions of the strongly chelating ligand HN(PO(O R)(2))(2). The cation ratios were measured by Total Reflexion X-Ray Fluores cence (TXRF) analysis and the single crystal structures of the polymeric K/Rb+ as well as the Rb+/Cs+ imidodiphosphate salts determined by X-ray stru cture analysis. The selectivity of the various alkali ions for insertion in the crystal lattices of the individual imidodiphosphate salts has been con firmed by concentration-dependent crystallizations and discussed based on t he structural analysis of the differing ligand conformations. The unit cell parameter dependence on the alkali cation radii provided information on va n der Waals interactions between adjacent phenyl rings of the imidodiphosph ate ligands and suggests the selective alkali cation insertion to be partly due to supramolecular repulsion within the lipophilic phenyl skin during t he self-aggregation of the polymeric salt chains.