Efficient formation of lipophilic dihydroxotin(IV) porphyrins and bis-porphyrins

Treatment of dichloro- and dicarboxylato-tin(IV) porphyrins with K2CO3 in THF–H2O (4 ∶ 1) is a mild and highly efficient method for formation of dihydroxotin(IV) porphyrins; unlike other reported procedures, this method is especially good for lipophilic porphyrins and bis-porphyrins. The synthesis of the mixed metal dihydroxotin(IV) zinc(II) bis-porphyrins 15 and 21 from the corresponding monozinc(II) free-base bis-porphyrins 13 and 19 without loss of the coordinated zinc(II) by hydrolysis or transmetalation illustrates the usefulness and mildness of the methodology.