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A family of bandgap-tunable pyrroles structurally related to rylene dyes was computationally designed and prepared using robust, easily scalable chemistry. These pyrroles show highly variable fluorescence properties and can be used as building blocks for the synthesis of electron-deficient oligopyrroles. The latter application is demonstrated through the development of π-extended porphyrins containing naphthalenediamide or naphthalenediimide units. These new macrocycles exhibit simultaneously tunable visible and near-IR absorptions, an ability to accept up to 8 electrons via electrochemical reduction, and high internal molecular free volumes. When chemically reduced under inert conditions, the most electron-deficient of these macrocycles revealed reversible formation of eight charged states, characterized by remarkably red-shifted optical absorptions, extending beyond 2200 nm. Such features make these oligopyrroles of interest as functional chromophores, charge-storage materials, and tectons for crystal engineering.

Octulene, the higher homologue of kekulene and septulene, was synthesized using the fold-in method. This new hydrocarbon macrocycle contains a large 24-membered inner circuit, which is peripherally fused to 24 benzene rings. Such an arrangement produces considerable hyperbolic distortion of the π-conjugated surface. The consequences of distortion in octulene were explored using photophysical methods, which revealed a reduced electronic band gap and greater flexibility of the π system. Octulene contains a functional cavity with a diameter larger than 5.5 Å that is capable of efficiently binding the chloride anion in a nonpolar solvent (K = 2.2(4)×10 m , 1 % dichloromethane (DCM) in benzene). The octulene-chloride interaction is stabilized by eight weak C(sp )H⋅⋅⋅Cl bonds, providing the first example of a hydrocarbon-based anion receptor.

The synthesis of dioxadiazuliporphyrinogen 7 and its oxidized forms: dioxadiazuliporphyrin 8 and dication 8(2+), is reported. These compounds were characterized in solution using UV-vis and 1H and 13C NMR spectroscopic means and in the solid state via single-crystal X-ray diffraction analysis. Dioxadiazuliporphyrin is a nonaromatic porphyrinoid, readily and reversibly oxidizable to its cation radical and to the aromatic carbaporphyrinoid dication, which can be viewed as a 21,23-dicarba-22,24-dioxaporphyrin with two fused tropylium rings. Further insight into the geometric and magnetic manifestations of aromaticity and antiaromaticity in the case of the redox couple 8, 8(2+) is obtained using density functional calculations and nucleus-independent chemical shifts.

A hexapyrrolohexaazacoronene derivative containing 37 fused rings, the largest such system to date, was obtained from a naphthalenomonoimide-pyrrole hybrid in a concise and efficient synthesis. This large heterocycle is electron-deficient and shows extended redox activity, spanning at least 13 oxidation levels, but is otherwise chemically stable. Radial expansion of the π system creates a chromophore characterized by strong fluorescence and solvatochromism in the neutral state, and strong near-infrared absorption in the charged states. Additionally, the enlarged and ruffled aromatic surface supports a unique self-assembly mode in the crystal, leading to the formation of highly solvated organic clathrates.

In this study, we reported a simple and efficient route for the one-pot sonochemical synthesis of substituted 3-pyrrolin-2-ones by citric acid as an additive.

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Chiral heteroaromatic propellers based on radially p-extended hexapyrrolohexaazacoronenes were obtained in ac oncise synthesis from suitably functionalizedd onoracceptor monopyrroles.T oo vercome steric hindrance,anew cyclodehydrogenation method was developed, and it uses bromine electrophiles as oxidative coupling agents instead of the commonly employed high-potential oxidants.T he new reaction offers high yields of propeller-shaped targets,even for electron-deficient precursors,a nd shows electrophile-dependent stereoselectivity,w ith N-bromosuccinimide and dibromine yielding,r espectively D 6 -a nd C 2 -symmetric products. The propeller azacoronenes are chiral and can be separated into configurationally stable enantiomers.I na ddition to providing steric bulk, peripheral functionalization considerably affects the electronic properties of the propellers,w hich exhibit reduced optical and electrochemical band gaps,a nd amore clearly defined electroreduction behavior.