名称:
Novel 5-benzazolyl-10,15,20-triphenylporphyrins and β,meso-benzoxazolyl-bridged porphyrin dyads: Synthesis, characterization and photophysical properties
摘要:
Novel 5-benzazolyl-10,15,20-triphenylporphyrins and beta,meso-benzoxazole-linked diporphyrins were synthesized through La(OTf)(3) catalyzed reaction of newly prepared 5-(3,4-diam nophenyl)-10,15,20-triphenylporphyrin or 5-(3-amino-4-hydroxyphenyl)-10,15,20-triphenylporphyrin with aromatic aldehydes in 1,2-dichlorobenzene. On metalation with zinc acetate, freebase beta,meso-benzoxazole-linked diporphyrin was successfully converted to the Zn-Zn diporphyrin complex in good yield. The synthesized porphyrin analogues were characterized using electronic absorption, IR and H-1 NMR spectroscopy in addition to mass and elemental analyses. The fluorescence studies of 5-benzazolyl-10,15,20-triphenylporphyrins showed efficient intramolecular energy transfer from the pyrene and fluorene subunits to the porphyrin core. In addition, the fluorescence quenching observed in beta-meso-benzoxazolyl-bridged porphyrin dyads was attributed to the possible nonplanarity of it component of the diporphyrins. The freebase-Ni diporphyrin complex underwent strong emission quenching in comparison to that of freebase diporphyrin and dizinc diporphyrin analogues. (C) 2011 Elsevier Ltd. All rights reserved.