Insights into the Synthesis and the Solution Behavior of meso-Aryloxy- and Alkoxy-Substituted Porphyrins

meso-RO-appended (R = alkyl, aryl) porphyrins bearing one or two OR substituents at the tetrapyrrolic macrocycle were synthesized in good yields from 5,15-dibromo-10,20-diphenylporphyrins 2H(Br2DPP), Ni(Br2DPP) and Zn(Br2DPP) using an SNAr reaction. By varying the solvent, the base, the temperature, and the time of the reaction, the optimum conditions were established, and the selective introduction of one or two meso-RO substituents at the periphery of the macrocycle was achieved. Moreover, monofunctionalization of Ni(Br2DPP) according to an SNAr reaction was used as a key step for the synthesis of rarely explored unsymmetrical porphyrinyl alkyl ethers. H-1 NMR studies of these ethers in CDCl3 revealed concentration-dependent aggregation of the zinc derivative through coordination of the central metal ion of one molecule to the peripheral oxygen atom of a second tetrapyrrolic macrocycle.