Synthesis,Characterization And Properties Of Porphrin-based Metal-Organic-Gel

Recently,mesoporous materials have drawn much attention and been applied in numerous fields,owning to their high surface area as well as outstanding thermal stability.An efficient and easy way to fabricate mesoporous materials is using metal-organic gel(MOG)as the raw materials.As we all know,porphyrin has been used as sensitizer,catalyst and medicine in the cure of cancer as a result of their special physical-chemistry activity.Up to now,there is little paper about porphyrin-based MOG.As reported in the previous articles,the porphyrin-based MOGs almost belong to the supramolecular gel(physical gel),with bad mechanical property and low thermal stability,which limit their use as mesoporous materials seriously.To solve this problem,we designed and synthesized six rigid porphyrins,named tetra(4-aminophenyl)porphyrin(TAPP),tetra(4-carboxyphenyl)porphyrin(TCPP),5,10,15-tris(4-carboxyphenyl)-20-phenylporphyrin(P1),5,15-di(4-carboxyphenyl)-10,20-diphenylporphyrin(P2),5-(4-carboxyphenyl)-10,15,20-triphenylporphyrin(P3)and 5-(4-carboxylphenyl)-10,15,20-tris(4-pyridyl)porphyrin(P4).The MOG1 was prepared by solvothermal method with TAPP and Co(Ac)2·4H2O as start materials.In the same way,MOG2,MOG3,MOG4 were prepared by the reaction of TCPP with Cr(NO3)3·9H2O,Al(NO3)3·9H2O and Fe(NO3)3·9H2O,respectively.MOG5,MOG6 were obtained by P1 reacting with Cr(NO3)3·9H2O,Al(NO3)3·9H2O,respectively;And MOG7,MOG8 were obtained by P2 and P4 reacting with Cr(NO3)3·9H2O,respectively.Finally,when TAPP reacted with both of Co(Ac)2·4H2O and Ni(Ac)2·7H2O,we obtained a porphyrin-based MOG containing two different metal ions,marked MOG9.Similarly,MOG10 was prepared by using TAPP,Co(Ac)2·4H2O and Mn(Ac)2·4H2O as start materials.Moreover,we investigated the influence factors in the formation and drying process of porphyrin-based MOG.The results showed that xerogel obtained by simply drying the wet gel at room temperature was collapsed easily.In order to fabricate metal-organic aerogel with stable mesoporous structure,we dried the porphyrin wet gel under the supercritical conditions of CO2,and obtained the corresponding aerogels MOA1-MOA10.These aerogels were characterized by SEM,TEM,FT-IR,and N2 absorption-desorption.Finally,we tested their catalytic activities in the oxidation of ethylbenzene;Their adsorption capacities to some solvents and dyes were also evaluated.