On a possible role of dicarboxylate ions in the formation of open-framework metallophosphates

Abstract

Three dicarboxylic acids (oxalic, malonic and terephthalic) were investigated as possible pillars in the formation of metallophosphates with extended structures in the presence of 1,2-diaminopropane (DAP) as a structure-directing agent. Only the oxalate ion was proven to be a suitable building block in the formation of hybrid networks. The terephthalate ion seems to possess the ability to be structurally involved in lattice formation, although not in networks of the hybrid type. The malonate ion in this system showed no propensity towards lattice formation, i.e., malonic acid merely exits as an intercalated species inside the 2-D zincophosphate structure. Different pillar-functioning ability has been attributed to structural differences of the three dicarboxylate ions.