Synthesis, Structures And Properties Of Porphyrin-polyoxometalates Hybrids

Porphyrins are a class of naturally occurring macrocyclic compounds, which play a very important role in the metabolism of living organisms. Porphyrins and their metal complexes have been found application as catalysts, sensors and molecular electronic devices. Polyoxometalates are remarkable for their important optical, electronic, magnetic characters owning to their nanometer-sized shapes and electronic structures involving d-Ï€ orbits and d-Ï€ electrons. Therefore, the compound porphyrins modified by polyoxometalates will produce new optical and electronic characters.It is very important for developing new organic-inorganic hybrid material.Eight porphyrins compounds have been prepared and characterized through IR, UV-vis spectroscopic analyses in this paper. The mechanism and substituent effect of porphyrins derivatives UV-Vis spectra have been studied in depth.lts UV-Vis spectra includes Soret band and Q bands. The Soret band absorption was attributed toÏ€â†'Ï€*(a2uâ†'eR*) of porphyrin ring in420nm and Q bands containing of four weak absorption peaks ware caused by Ï€â†'Ï€*(a1uâ†'eR*) of porphyrin ring. Compared to porphyrin, the Q bands of metalloporphyrin have turned into two absorption peaks. In addition, the absorbance bands of the porphyrin with electron withdrawing group were blue-shifted, otherwise, the absorbance bands were red-shiftedTwo alkylimido derivatives of hexamolybdate,(Bu4N)2[Mo6O18(N2-C6H4COOCH3)] and (Bu4N)2[Mo6O18(N2-C6H4COOCH2CH3)] have been synthesized by a reaction of [(C4H9)4N]4[a-Mo8O26] and aminobenzoate hydrochloride with N,N’-dicyclohexyl-carbodiimide (DCC) as a dehydrating agent in dry acetonitrile solution. The products have been characterized through routine spectroscopic analyses (IR,1H NMR, UV-Vis) and their structural determinations were studied through single crystal X-ray crystallography. The anions of (Bu4N)2[Mo6O18(N2-C6H4COOCH3)] generate one-dimensional chain through intermolecular hydrogen bond (C3-O9…H3).The anions of (Bu4N)2[Mo6O18(N2-C6H4COOCH2CH3)] are more complex, Each hexamolybdate anion have formed the intramolecular hydrogen bond through C9A-H9AC…O11, then two inversion hexamolybdate anions have been assembled into a dimer throughC5A—O7…H5A. In addition, there have been the Ï€-Ï€ stacking interactions in dimer. Finally, these dimmers have been linked into an infinite one-dimensional polymolybdate chain via C3A—O19…H3A hydrogen bonds. On the basis of the previous research, the author have explored the synthesis of covalent and ionic porphyrin-polyoxometalate compound. In addition, the synthesis and propertise need further research.