Synthesis and reactions of 20 π-electron β-tetrakis(trifluoromethyl)-meso-tetraphenylporphyrins

The 20 pi-electron nonaromatic isophlorin 2 had been successfully isolated and thoroughly characterized and was formed by reduction of Cu(II) beta-tetrakis(trifluoromethyl)-meso-tetraphenylporphyrin (Cu1) with activated zinc powder. However, the reaction utilizing Ni(II) beta-tetrakis(trifluoromethyl)-meso-tetraphenylporphyrin (Ni1) as a substrate and Na2S2O4 as a reductant at 100 degrees C resulted in the formation of a porphydimethene 5. Subsequent N-methylation of the isophlorin 2 led to N-dimethylated isophlorin 3 or N-tetramethylated isophlorin 4 depending on the choice of the base used.