Porphyrins and related compounds

N-confused tetrahydroxyphenyl and tetra-alkoxyphenyl porphyrins represented as:

• and the corresponding chlorins (dihydroporphyrins) and bacteriochlorins (tetrahydroporphyrins), including tautomers in all cases, and their metallates and salts, including internal salts:
• —OR1 standing for a hydroxy group (R1=hydrogen) or an alkoxy group where R1 is a branched or unbranched alkyl group containing from 1 to 4 carbon atoms, and where OR1 may be at any position on the phenyl ring but particularly meta and there may be zero, one, two or three groups per phenyl ring provided at least one of the rings is substituted and
• —R standing for hydrogen, when IIB and IIA represent the same molecule, or
• R═X, a branched or unbranched alkyl group of 1 to 6 carbon atoms, or an aralkyl group the alkyl chain of which contains 1 to 3 carbon atoms, or alternatively
• R═XY where X is as last and Y consists of 1 to 3 substituents which are attached to any of the carbons in X and may be linked, and which are selected from:
• ═—SO3H, CO2H and their C1 to C12 esters and amides.
• ═—OH or OR2 where R2=a polyhydroxylated alkyl chain from 1 to 20 carbon atoms, e.g. a carbohydrate or a folic acid residue.
• ═—NR3R4 where R3, R4 are the same or different and may be hydrogen or an alkyl group of 1 to 12 carbon atoms or a polyhydroxylated alkyl chain or folic acid residue as last.
• =Z—P where P is an end-capped polyalkylene preferably polyethylene glycol group of molecular weight of 2,000 to 100,000, preferably 5,000 to 40,000 and very preferably 10,000 to 20,000 Da and Z is a linker group to attach P e.g. the —O(C═O)NH(CH2)6NH(C═O)O— group.
• R5=hydrogen, a halogen or a nitro group.