Synthesis of N-fused dithia and dibenzihomoporphyrins

N-Fused dithia and dibenzi homoporphyrins have been synthesized using a[2+2]approach by condensing one equivalent of appropriate dithienyl/di p-phenylene ethene diol with one equivalent of N-confused dipyrromethane in CH_(2)Cl_(2) under mild acid catalysed conditions.The X-ray structure obtainedfor the N-fused dibenzi homoporphyrin revealed that the fused tripentacyclic ring was planar and wastilted by an angle of 11.35°whereas the p-phenylene moieties were highly deviated by angles of 48.70°and 50.93°from the mean plane defined by five meso carbon atoms.The NMR and absorption featuressuggested the non-aromatic nature of both N-fused dithia and dibenzi homoporphyrins.The DFT studiesrevealed that the N-fused dithia homoporphyrin was highly distorted with one thiophene ring facingoutside the macrocyclic cavity.The spectral features of both N-fused dithia and dibenzi homoporphyrinswere supported by TD-DFT studies.