Both-faces hindered porphyrins. Part 4. Synthesis of functionalized basket-handle porphyrins designed for a strict intramolecular axial ligation in superstructured complexes

Abstract

The concept of basket-handle porphyries, in a cross-trans configuration, is applied to the design of new compounds which possess a chemical group attached to the central carbon of one bridging chain in order to mimic the axial co-ordination of the active site of hemoproteins. The key intermediates used in these syntheses are prepared from 5,1 0,1 5,20-tetraphenylporphyrin the two phenyl groups in opposing positions of which are bridged by a ketonic chain, whilst the two other phenyl groups carry a polymethylene chain, (8b) and (24), or a pyridyl one, (33) and (41), via ether or amide linkages. These compounds are clearly reduced to alcohol derivatives which may be further derivatived under mild conditions to give functionalized porphyries having pendant 0, N, and S donor chemical groups as potential axial ligands. Additional diketonic porphyries (8c) and (40) have been obtained during the preceding synthesis to allow the preparation of symmetrical disubstituted compounds. The characterization of these new superstructured porphyries was established by ¹H n.m.r. spectroscopy as well as the relative inner or outer position of the substituted chemical groups.