Synthesis and Properties of a Covalently Linked Angular Perylene Imide Dimer

Utilizing the unexplored chemistry of a monocarbon analog to perylene bisimide, a covalently linked angular perylene dimer was synthesized. On the basis of measured optical properties and molecular modeling, the spectral changes relative to a monomeric reference perylene can be explained by an angle-dependent oblique exciton coupling model. With a roughly trigonal interchromophore arrangement, the dimer building block is promising for larger, cyclic assemblies to mimic naturally occurring light harvesting complexes

Regioselectivity in Sequential Nucleophilic Substitution of Tetrabromonaphthalene Diimides

Nucleophilic substitution of tetrabromosubstituted naphthalene diimides (NDIs) with aniline was studied in detail to explore the regioselectivity as three different diamino-substituted regioisomeric products can be formed. We found that the regioselectivity of the nucleophilic disubstitution of 2,3,6,7-tetrabromonaphthalene diimide with aniline is dependent on reaction solvents and additives. In dichloromethane and chloroform without an additive the 2,7-diamino-3,6-dibromo-NDI isomer was formed regioselectively, while in DMF under similar reaction conditions the 2,3-diamino-6,7-dibromo isomer was observed as the major regioisomer. The third possible regioisomer 2,6-diamino-3,7-dibromo product was formed, if at all, in an insignificant amount. Tetrabutylammonium fluoride (TBAF) additive exerts a dramatic effect on the regioselectivity of this reaction, as in dichloromethane without TBAF the 2,7-diamino isomer was formed regioselectively, while without TBAF the 2,3-diamino isomer was formed exclusively. This remarkable effect of TBAF can be rationalized in terms of a deprotonation of the monoamino-tribromo-NDI generated in the first step of this sequential reaction as an intermediate by fluoride ions leading to an anionic species as indicated by UV–vis and NMR experiments whose electronic properties direct the regioselective attack of the second amine molecule. Our efforts led to the exclusively regioselective synthesis of 2,7-diamino-3,6-dibromo- and 2,3-diamino-6,7-dibromo-NDIs for the first time

Synthesis of a Non-aggregating Bay-Unsubstituted Perylene Bisimide Dye with Latent Bromo Groups for C–C Cross Coupling

To address the absence of synthetic routes to access easily functionalizable, non-aggregating, and soluble bay-unsubstituted perylene bisimide dyes, an efficient, three-step, multigram-scale synthesis of the divergent building block <i>N</i>,<i>N</i>′-bis(4-bromo-2,6-diisopropylphenyl)perylene-3,4:9,10-tetracarboxylic bisimide is reported. Suzuki coupling yields new dyes that maintain excellent solubility and exhibit unity quantum yields in CHCl₃, THF, toluene, and CH₃CN. The methodology reported here enables access to dyes with sensitive functional groups such as aldehydes that are not accessible by traditional imidization routes

Synthesis of a Non-aggregating Bay-Unsubstituted Perylene Bisimide Dye with Latent Bromo Groups for C–C Cross Coupling

To address the absence of synthetic routes to access easily functionalizable, non-aggregating, and soluble bay-unsubstituted perylene bisimide dyes, an efficient, three-step, multigram-scale synthesis of the divergent building block <i>N</i>,<i>N</i>′-bis(4-bromo-2,6-diisopropylphenyl)perylene-3,4:9,10-tetracarboxylic bisimide is reported. Suzuki coupling yields new dyes that maintain excellent solubility and exhibit unity quantum yields in CHCl₃, THF, toluene, and CH₃CN. The methodology reported here enables access to dyes with sensitive functional groups such as aldehydes that are not accessible by traditional imidization routes

Diindole-Annulated Naphthalene Diimides: Synthesis and Optical and Electronic Properties of <i>Syn</i>- and <i>Anti</i>-Isomers

Here we report a selective method for the core-extension of naphthalene diimide (NDI) with two annulated indole rings leading to carbazolo­[2,3-<i>b</i>]­carbazole diimides (CbDIs) with exclusive <i>syn</i>-connectivity based on a regioselective nucleophilic substitution reaction of Br₄-NDI with arylamines, followed by palladium-catalyzed intramolecular C–C coupling. The oxygen analogues of <i>anti</i>-CbDIs, namely <i>anti</i>-benzofurobenzofuran diimides (<i>anti</i>-BfDIs), were obtained from 2,6-Br₂-NDI and 2-bromophenol. The <i>syn</i>- and <i>anti</i>-isomers of CbDIs were unambiguously characterized by single-crystal X-ray analysis. The optical properties of the present core-enlarged NDIs were studied, revealing clear differences in the absorption characteristics of the <i>syn</i>- and <i>anti</i>-isomers of CbDI, on one hand, and CbDI vs BfDI derivatives, on the other hand. Cyclic voltammetry studies showed that the redox properties are dependent on the substituents at the CbDI-core and oxygen atom containing BfDIs are more prone to reduction than the respective nitrogen analogues CbDIs. Vacuum-processed organic field effect transistors reveal CbDI and BfDI derivatives with n-channel, p-channel, as well as ambient transport characteristics with mobility values up to 0.2 cm²/(V s)

Giant Electroactive M₄L₆ Tetrahedral Host Self-Assembled with Fe(II) Vertices and Perylene Bisimide Dye Edges

Self-assembly of octahedral Fe­(II) ions and linear perylene bisimide (PBI) dyes with 2,2′-bipyridine groups covalently attached at the imide positions quantitatively yields an Fe₄(PBI)₆ tetrahedron by the directional bonding approach. With an edge length of 3.9 nm and estimated internal volume >950 ų, tetrahedron <b>T</b> is one of the largest M₄L₆ tetrahedra ever reported. Importantly, many of the desirable photo- and electroactive properties of the PBI ligands are transferred to the nanoscale metallo­supra­molecule. Tetrahedron <b>T</b> absorbs strongly across the visible spectrum out to 650 nm and exhibits a total of 7 highly reversible electrochemical oxidation and reduction waves spanning a 3.0 V range. This facile cycling of 34 electrons between +18 and −16 charged species is likely enabled due to the porous nature of the tetrahedron that allows the necessary counterions to freely flow in and out of the host. Host–guest encapsulation of C₆₀ by <b>T</b> in acetonitrile was studied by ¹³C NMR spectroscopy, UV–vis spectroscopy, and ESI-MS, confirming that the tetrahedron is a suitable host for large, functional guest molecules

Diindole-Annulated Naphthalene Diimides: Synthesis and Optical and Electronic Properties of <i>Syn</i>- and <i>Anti</i>-Isomers

Here we report a selective method for the core-extension of naphthalene diimide (NDI) with two annulated indole rings leading to carbazolo­[2,3-<i>b</i>]­carbazole diimides (CbDIs) with exclusive <i>syn</i>-connectivity based on a regioselective nucleophilic substitution reaction of Br₄-NDI with arylamines, followed by palladium-catalyzed intramolecular C–C coupling. The oxygen analogues of <i>anti</i>-CbDIs, namely <i>anti</i>-benzofurobenzofuran diimides (<i>anti</i>-BfDIs), were obtained from 2,6-Br₂-NDI and 2-bromophenol. The <i>syn</i>- and <i>anti</i>-isomers of CbDIs were unambiguously characterized by single-crystal X-ray analysis. The optical properties of the present core-enlarged NDIs were studied, revealing clear differences in the absorption characteristics of the <i>syn</i>- and <i>anti</i>-isomers of CbDI, on one hand, and CbDI vs BfDI derivatives, on the other hand. Cyclic voltammetry studies showed that the redox properties are dependent on the substituents at the CbDI-core and oxygen atom containing BfDIs are more prone to reduction than the respective nitrogen analogues CbDIs. Vacuum-processed organic field effect transistors reveal CbDI and BfDI derivatives with n-channel, p-channel, as well as ambient transport characteristics with mobility values up to 0.2 cm²/(V s)

Diindole-Annulated Naphthalene Diimides: Synthesis and Optical and Electronic Properties of <i>Syn</i>- and <i>Anti</i>-Isomers

Here we report a selective method for the core-extension of naphthalene diimide (NDI) with two annulated indole rings leading to carbazolo­[2,3-<i>b</i>]­carbazole diimides (CbDIs) with exclusive <i>syn</i>-connectivity based on a regioselective nucleophilic substitution reaction of Br₄-NDI with arylamines, followed by palladium-catalyzed intramolecular C–C coupling. The oxygen analogues of <i>anti</i>-CbDIs, namely <i>anti</i>-benzofurobenzofuran diimides (<i>anti</i>-BfDIs), were obtained from 2,6-Br₂-NDI and 2-bromophenol. The <i>syn</i>- and <i>anti</i>-isomers of CbDIs were unambiguously characterized by single-crystal X-ray analysis. The optical properties of the present core-enlarged NDIs were studied, revealing clear differences in the absorption characteristics of the <i>syn</i>- and <i>anti</i>-isomers of CbDI, on one hand, and CbDI vs BfDI derivatives, on the other hand. Cyclic voltammetry studies showed that the redox properties are dependent on the substituents at the CbDI-core and oxygen atom containing BfDIs are more prone to reduction than the respective nitrogen analogues CbDIs. Vacuum-processed organic field effect transistors reveal CbDI and BfDI derivatives with n-channel, p-channel, as well as ambient transport characteristics with mobility values up to 0.2 cm²/(V s)

A General Synthetic Route to Polycyclic Aromatic Dicarboximides by Palladium-Catalyzed Annulation Reaction

Here we report a general method for the synthesis of polycyclic aromatic dicarboximides (PADIs) by palladium-catalyzed annulation of naphthalene dicarboximide to different types of aromatic substrates. Reaction conditions were optimized by systematic variation of ligand, solvent, and additive. It was shown that solvent has a decisive effect on the yield of the reaction products, and thus 1-chloronaphthalene as solvent afforded the highest yield. By applying the optimized reaction conditions, a broad series of planar carbo- and heterocycle containing PADIs were synthesized in up to 97% yield. Moreover, this approach could be applied to curved aromatic scaffold to achieve the respective bowl-shaped PADI. Two-fold annulation was accomplished by employing arene diboronic esters, affording polycyclic aromatic bis­(dicarboximides). The optical and electrochemical properties of this broad series of PADIs were explored as well

Electron-Poor Bowl-Shaped Polycyclic Aromatic Dicarboximides: Synthesis, Crystal Structures, and Optical and Redox Properties

Two new bowl-shaped polycyclic aromatic hydrocarbons, based on corannulene and naphthalene dicarboximide, are synthesized by an improved Suzuki–Miyaura cross-coupling and C–H arylation cascade reaction. Crystallographic analyses confirm structural assignments and provide insight into molecular interactions in the solid state. The new bowl-shaped molecules show reversible oxidation and reduction, intense visible range absorption, and high fluorescence quantum yields. These molecules can be considered bowl-shaped congeners of planar perylene dicarboximides