Hydroporphyrins basicity

The j8 hydrogens of the pyrroline rings are substituted with deuterium under basic conditions (BulOK-BulOD/THF, r.t) without isomerization to other hydroporphyrins. The acidic proton-... 

There are several other nonaromatic hydroporphyrins known.2 14 Phlorins (5,22-dihydropor-phyrins) are stable only in acidic media (El/2 —0.04 V vs. SCE, pH2/HCl) but easily oxidized to porphyrins under neutral to basic conditions (El/2 = — 0.5 to — 0.7 V vs. SCE) unless the methylene bridge is blocked with substituents. Their spectra are characterized by two bands at 430nm (e 105) and 650 nm (broad). The former is accompanied by a band at 370nm (s 104), and both red-shift by 20 nm on metallation. The latter shifts to 750 nm on protonation and to more than 800 nm on metallation. Phlorins are at the same oxidation level as chlorins, and are the intermediates of photochemical conversions of porphyrins to chlorins. 

Hydrogen ligands, 689-711 Hydrogen selenide metal complexes, 663 Hydrogen sulfide metal complexes, 516 Hydrogen telluride metal complexes, 670 Hydroporphyrins, 814-856 basicity, 853 dehydrogenation, 853 demetallation, 854 deuteration, 853 mass spectra, 852 metallation, 854 NMR, 852 non-aromatic, 855 photochemistry, 854 redox chemistry, 855 synthesis, 852... 

Nomenclature follows IUPAC recommendations (79PAC2251). The basic macrocyclic system I is named porphyrin, which implies that the pyrrolic nitrogen atoms are placed in positions-21 and -23, regardless of the structure of the actual tautomer. Hydro prefixes are then considered in ascending numerical order. I attempt here to maintain the arrangements of the formulas of hydroporphyrins resulting from these rules. 

The relative basicities of hydroporphyrins as inversely related to the strength of phosphoric acid needed to extract them from benzene solution are TPP > TPC s TPiBC > TPBC (69JA7485). 

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