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[摘要]：Two types of beta- functionalized (mono nitrated and perbrominated) meso tetrakis(5-halothien-;2-yl) porphyrins, which can be used as precursors for the synthesis of other asymmetric and highly substituted porphyrins, have been synthesised and characterized. Introduction of a nitro group at the beta- position shifted soret band 11-16 nm to the red region and redox potentials to > 170 mV for oxidation and > 250 mV for reduction anodically. Perbromination of halothienylporphyrins lead to enhanced bathochromically shifted uv- visible spectral bands, but had only marginal influence on oxidation potentials. Effect of mono nitro group and eight bromo groups on the electronic properties of the porphyrins is attributed, respectively to, the electron deficiency created in the porphyrin pi- system and the nonplanar conformation induced by the bulky bromo groups. |
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