ABSTRACT
The synthesis of various periphery-substituted shape-persistent cage compounds by twelve-fold condensation reactions of four triptycene triamines and six salicyldialdehydes is described, where the substituents systematically vary in bulkiness. The resulting cage compounds were studied as permanent porous material by nitrogen sorption measurements. When the material is amorphous, the steric demand of the cages exterior does not strongly influence the gas uptake, resulting in BET surface areas of approximately 700â m(2) g(-1) for all cage compounds 3 c-e, independently of the substituents bulkiness. In the crystalline state, materials of the same compounds show a strong interconnection between steric demand of the peripheral substituent and the resulting BET surface area. With increasing bulkiness, the overall BET surface area decreases, for example 1291â m(2) g(-1) (for cage compoundâ 3 c with methyl substituents), 309â m(2) g(-1) (for cage compound 3 d with 2-(2-ethyl-pentyl) substituents) and 22â m(2) g(-1) (for cage compound 3 e with trityl substituents). Furthermore, we found that two different crystalline polymorphs of the cage compoundâ 3 a (with tert-butyl substituents) differ also in nitrogen sorption, resulting in a BET surface area of 1377â m(2) g(-1), when synthesized from THF and 2071â m(2) g(-1), when recrystallized from DMSO.
ABSTRACT
The one-pot three component synthesis of metal containing microporous organic polymers with high BET surface areas is presented. The metal salphen units were built during the formation of the porous polymers. Selective gas adsorption depending on the metal ions is discussed.