Porphyrin, single-face-hindered

As the formation of five-coordinate complexes with nitrogenous bases largely depends on the size of the host cavity, single-face-hindered porphyrins have been developed pocket [40], cyclophane [41-44], bridged [45], crowned [46], capped [47-53], strapped [54-60] and hybrid [61], In these compounds, the size and the chemical nature of the superstructure can be conveniently varied by changing the number of methylene groups and the aromatic substituent incorporated. 

This strategy has also been independently proposed by Battersby and coworkers [87-89] to produce doubly strapped porphyrins. They used the diacid chloride of coproporphyrin I (28) as the starting compound. Coupling reactions with anthracenediol gave the single-faced-hindered porphyrin (29). 

Mono-axially coordinated species are most conveniently formed by the reaction of single face-hindered Fe(II) porphyrins with isocyanide in a non-coordinating solvent, such as toluene or benzene,or when four-coordinate PFe are reacted under an inert atmosphere with nitrogen bases, such as imidazoles and pyridines in the presence of isocyanide This... 

Gerothanassis, I. R, Momenteau, M. (1987). NMR spectroscopy as a tool for studying synthetic oxygen carriers related to biological systems Application to a synthetic single-face hindered iron porphyrin-dioxygen complex in solution, J. Am. Chem. Soc., 109 6944. 

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