A simple strategy has been developed for the synthesis of α,α′-dibenzoylbenzodipyrroles, which are key synthons for the synthesis of fused porphyrinoids. α,α′-Dibenzoylbenzodipyrroles were characterized by high-resolution mass spectrometry (HRMS), NMR, and X-ray crystallography. To show the use of α,α′-dibenzoylbenzodipyrrole, we synthesized five different fused meso-aryl sapphyrins under acid-catalyzed reaction conditions. α,α′-Dibenzoylbenzodipyrrole was reduced to diol and condensed with five different tripyrranes such as aza, oxa, thia, selena, and telluratripyrranes under mild acid-catalyzed conditions to afford fused meso-aryl sapphyrins in 15–18% yields. One-dimensional (1D) and two-dimensional (2D) NMR studies revealed that in fused sapphyrins, the furan ring in oxabenzosapphyrin and the pyrrole ring in benzosapphyrin, which are present opposite to the benzodipyrrole moiety, attained ring inversion (inverted sapphyrins), whereas the selenophene ring in selenabenzosapphyrin and the tellurophene ring in tellurabenzosapphyrin did not show ring inversion (normal sapphyrins). However, thiabenzosapphyrin exhibits both normal and inverted conformations in different ratios. All fused sapphyrins showed typical aromatic absorption features; however, the absorption features of normal fused sapphyrins are different from the inverted fused sapphyrins. Redox studies indicate that normal fused sapphyrins are difficult to oxidize but easier to reduce compared to inverted fused sapphyrins. Density functional theory (DFT) studies support the experimental observations.

We report the synthesis of rare examples of nonaromatic doubly fused fluorene embedded heterosapphyrins by [3+2] condensation of 2,7-bis((1H-pyrrol-2-yl)(p-tolyl)methyl)-9H-fluorene (fluorene based tripyrrane) and [2,2'-bithiophene]-5,5'-diylbis(4-aryl)methanol] (bithiophene diol) in CH2Cl2 using BF3.OEt2...

A series of novel covalently linked meso‐BODIPYnyl dithiahomoporphyrins was synthesized by treating readily available tetrapyrrane and appropriate formyl BODIPY derivatives in the presence of catalytic amount of BF3·OEt2 in CH2Cl2 followed by oxidation using DDQ. The meso‐BODIPYnyl dithiahomoporphyrins were characterized by HR‐MS, 1D, 2D NMR and absorption spectroscopy, cyclic voltammetry and DFT studies. The spectral and electrochemical studies suggest that the BODIPY and homoporphyrin units in meso‐BODIPYnyl dithiahomoporphyrins retain their original identities. The compounds were non‐fluorescent due to intramolecular charge transfer from dithiahomoporphyrin moiety to a respective BODIPY unit in meso‐BODIPYnyl dithiahomoporphyrins. The DFT studies supported the intramolecular charge transfer between the two chromophores in meso‐BODIPYnyl dithiahomoporphyrins.

A simple rapid synthetic route is developed to synthesize new fused meso-aryl oxasapphyrins in 8–10% yield using easily accessible 3-benzoylpyrrole as the key precursor. The method involves McMurry coupling of 3-benzoylpyrrole to obtain an E/Z mixture of dipyrroethene, which was subjected to benzoylation followed by NaBH4 reduction to afford dipyrroethene diol in situ that was then condensed with 16-oxatripyrrane under mild acid-catalyzed conditions to afford fused oxasapphyrins.