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Bench‐stable meso‐substituted di(p/m‐benzi)homoporphyrins were synthesized through acid‐catalyzed condensation of dipyrrole derivatives with aryl aldehydes. The insertion of a 1,1,2,2‐tetraphenylethene (TPE) or but‐2‐ene‐2,3‐diyldibenzene unit in the porphyrin framework results in the formation of dibenzihomoporphyrins, merging the features of hydrocarbons and porphyrins. Single crystal X‐ray analyses established the non‐planar structure of these molecules, with the phenylene rings out of the mean plane, as defined by the dipyrromethene moiety and the two meso‐carbon atoms. Spectroscopic and structural investigations show that the macrocycles exhibit characteristics of both TPE or but‐2‐ene‐2,3‐diyldibenzene and dipyrromethene units indicating the non‐aromatic characteristics of the compounds synthesized. Additionally, the dibenzihomoporphyrins were found to generate singlet oxygen, potentially allowing their use as photosensitizers., A series of dibenzihomoporphyrins were synthesized by incorporation of phenylene para‐ and meta‐linkages into the macrocycles. Structural elucidation revealed non‐aromatic property due to a lack of effective π‐conjugation and non‐planarity of the macrocycles. Furthermore, these macrocycles were shown to act as photosensitizers for singlet oxygen generation.John Wiley & Sons, Ltd.

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 BF3OEt2 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.

Stable nonaromatic [20] dithiaporphyrin (2.1.1.1) macrocycles were synthesized in decent yields by condensing readily available butene-2,3-diyl-bisthiophene-2,5diyl-bis(p-methoxyphenylmethanol) with different meso-aryl dipyrromethanes under mild acid catalyzed conditions. The [20]clithiaporphyrin (2.1.1.1) macrocydes are the first members of the expanded poiphyrin analogues of [18]dithiaporphyrin (1.1.1.1) and consist of two pyrroles and two thiophenes connected through five meso-carbon bridges. The [20]dithiaporphyrin macrocycles were confirmed by mass spectroscopy, 1D and 2D NMR spectroscopy, and X-ray crystallography. The X-ray structure revealed that the macrocycle is highly distorted and that the two thiophene rings are completely out from the "mean-plane" defined by the dipyrromethene moiety and the two meso-carbons. In the absorption spectrum, the macrocycles showed one strong band at similar to 420 nm and one weak band at similar to 720 nm. The electrochemical studies revealed that the macrocycles are stable under redox conditions. The metal sensing studies indicated that these macrocycles have the potential to sense specific metal ions such as Hg2+ ions. Two covalently linked dithiahomoporphyrin fluorophore dyads were synthesized by coupling iodo-functionalized dithiahomoporphyrin with an ethynyl-functionalized fluorophore such as boron dipyrromethene (BODIPY) and BF2 smaragdyrin under mild Pd(0) coupling conditions. The potential of these dyads as a fluorescent sensor for Hg2+ was explored, and the studies indicated that both dyads can be used as fluorescent sensors.

A series of new [20]dioxahomoporphyrins have been synthesized by [2+2]condensation of (but-2-ene-2,3-diyldifuran-2,5-diyl) bis(p-methoxyphenylmethanol) with appropriate meso-aryldipyrromethanes under mild acid-catalyzed conditions. The X-ray structure determined for one of the dioxahomoporphyrins revealed that the macrocycle is significantly distorted and the two furan rings are completely out-of-plane from the mean plane. The [20]dioxahomoporphyrin macrocycles are stable and non-aromatic, and have been characterized in detail by HRMS, 1D and 2D NMR spectroscopy, UV/Vis spectrophotometry and electrochemical techniques. The iodo-functionalized [20]dioxahomoporphyrin was used to synthesize a covalently linked diphenylethyne-bridged [20]dioxahomoporphyrin- porphyrin dyad by coupling with an ethynyl-functionalized porphyrin under mild copper-free Pd-0 catalytic conditions. The metallation of the porphyrin macrocycle of the [20]dioxahomoporphyrin- porphyrin dyad was carried out by treating the dyad with the appropriate metal salt under standard conditions and the resulting [20]dioxahomoporphyrin-metalloporphyrin dyads were characterized by various spectral and electrochemical techniques. The results of the studies indicated that in the dyads the dioxahomoporphyrin and porphyrin/metalloporphyrin units interact weakly and retain their individual features.