Synthesis and Redox Properties of Superbenzene Porphyrin Conjugates

Abstract

Superbenzene porphyrin conjugates find wide range of applications from nonlinear optical materials to semiconductors. Herein, we report the synthesis and characterization of 5,15-bis(3,5-di-tert-butylphenyl)-10,20-bis-(pentaphenylphenyl)phenylporphyrin and its Zinc-metallated complex. Oxidative planarization of 5,15-bis(3,5-di-tert-butylphenyl)-10,20-bis(pentaphenylphenyl)phenylporphyrin and its metallated complex was carried out by using NOBF 4 as an oxidizing agent. The formation of superbenzene porphyrin conjugates validates its Scholl type reactions. The laboratory-synthesized porphyrin conjugates were characterized experimentally using spectroscopic techniques such as 1 H NMR, 13 C NMR, electron spin resonance, and ultraviolet−visible spectroscopy for structural conformation. In addition, density functional theory calculations were carried out to validate the experimental results. The theoretical and experimental results show that the 4-(pentaphenylphenyl)phenyl ligand increases the stability, optical properties, and rate of planarization of synthesized porphyrins. The conjugates exhibited intense and distant electronic communication between two hexabenzocoronene sites, taking advantage of porphyrin as a π-spacer. The π-radical cation has also been found to be an intermediate in oxidative C−C bond formation. NICS calculations support such a conclusion.

Synthesis of Chrysoporphyrins and a Related Benzopyrene-Fused System

“…However, in our hands the dihexyl-substituted nickel(II) complex 26d failed to cyclize with a variety of reagents including ferric chloride, DDQ, Sc(OTf) 3 -DDQ, 28 and nitrosonium tetrafluoroborate. 29 Similarly, no cyclization was observed for free base porphyrin 11c under most of these conditions. Fortunately, reaction of 11c with ferric chloride proved to be the exception.…”

“…Scholl reactions with porphyrins have been well studied and are often carried out on metalated derivatives. However, in our hands the dihexyl-substituted nickel­(II) complex 26d failed to cyclize with a variety of reagents including ferric chloride, DDQ, Sc­(OTf) 3 -DDQ, and nitrosonium tetrafluoroborate . Similarly, no cyclization was observed for free base porphyrin 11c under most of these conditions.…”

Applications of supramolecular assemblies in drug delivery and photodynamic therapy

“…48 The applications of hexa-cata-hexabenzocoronene have been rarely reported to date. Porphyrin conjugates based on hexabenzocoronene display photochromism, are capable of showing absorption in NIR of electromagnetic spectrum [49][50][51] and are anticipated to be viable candidates for PDT and magnetic resonance imaging. Multifunctionalized fluorescent dyes are of great interest for photo based cancer theranostics.…”

Diels–Alder Cycloaddition with CO, CO2, SO2, or N2 Extrusion: A Powerful Tool for Material Chemistry

“…Nisa et al, employed DA cycloaddition with CO extrusion and cyclodehydrocondensation in synthesizing porphyrin bearing two Ph 5 Ph or two HBC motifs ( Scheme 155 ) [ 209 ]. Moreover, Zn-complexes of the ligands mentioned above were synthesized.…”

“… DA cycloaddition with CO extrusion and Scholl reaction engaged in synthetic route leading to the porphyrins equipped with the Ph 5 Ph or HBC-motifs [ 209 ]. Reagents and conditions: a = Ph 2 O, 260 °C; b = next steps; and c = Scholl reaction.…”