1,6- and 1,7-regioisomers of dinitro- and diamino-substituted perylene bisimides: synthesis, photophysical and electrochemical properties

Regiochemically Pure 1,6-Ditriflato-Perylene Diimide: Preparation and Transformation

Preparation of regioisomerically pure 1,6-disubstituted perylene diimide (PDI) is not a trivial task owing to the lack of facile synthetic and separation methodologies for the precursors. Herein, we present a simple synthesis for 1,6-ditriflato-PDI (1,6-diOTf-PDI) using 1,6,9,10-tetrabromo-perylene monoimide 1 as the starting material. The selective methoxylation of 1 at the 1,6-position is the key step. Based on a four-step sequence of selective methoxylation, domino carbonylative amidation, demethylation, and triflation, 1,6-diOTf-PDI can be obtained in a satisfactory yield. Moreover, as a building block, 1,6-diOTf-PDIa can readily undergo Suzuki and Sonogashira cross-coupling reactions.

Visible-Light-Mediated Synthesis of AzaBenzannulated Perylenediimide-Based Light-Harvesting Dyads

Intramolecular imine photocyclization has been explored for grafting on the bay region of perylenediimide (PDI) different electro- and photoactive chromophores to achieve new AzaBenzannulated-PDI (AzaBPDI) dyads. Triphenylamine (TPA), fluorene (Fl), perylenemonoimide (PMI), and perylenediimide (PDI) units have been successfully assembled to AzaBPDI using this straightforward one-pot synthesis starting from the easily accessible 1-aminoPDI. This original procedure was compared to the well-known Pictet-Spengler reaction and appears to be an attractive alternative in terms of versatility and efficiency with higher yields obtained. The optical and electrochemical properties of these molecular systems demonstrated large absorption capabilities in the visible range, good accepting abilities with low LUMO levels, and efficient electronic interactions between chromophoric units such as energy or electron transfers. In addition, with their large dihedral angle estimated by theoretical calculations, those dyads should present interesting applications in various organic optoelectronic devices. In particular, the PMI-AzaBPDI and PDI-AzaBPDI dyads presenting low LUMO levels, a broad absorption in the visible range, and a twisted conformation make them good candidates as non-fullerene acceptors in organic solar cells.

Nitro-Perylenediimide: An Emerging Building Block for the Synthesis of Functional Organic Materials

Perylenediimide (PDI) is one of the most important classes of dyes and is intensively explored in the field of functional organic materials. The functionalization of this electron-deficient aromatic core is well-known to tune the outstanding optoelectronic properties of PDI derivatives. In this respect, the functionalization has been mostly addressed in bay-positions to halogenated derivatives through nucleophilic substitutions or metal-catalyzed coupling reactions. Being aware of the synthetic difficulties of obtaining the key intermediate 1-bromoPDI, we will present as an alternative in this review the potential of 1-nitroPDI: a powerful building block to access a large variety of PDI-based materials.

Progress in the synthesis of perylene bisimide dyes

Rapid progress in the synthesis of perylene bisimide dyes gave an old scaffold new life.

Influence of imide-substituents on the H-type aggregates of perylene diimides bearing cetyloxy side-chains at bay positions

A series of perylene-3,4:9,10-tetracarboxylic acid diimides (PDIs, namely TYR-PDI, AEP-PDI, CET-PDI, ANP-PDI and KOD-PDI), comprising long linear cetyloxy side-chains functionalized at the 1,7-bay positions and the different substituents (i.e., hydrophobic/hydrophilic segments) symmetrically linked at the two imide-positions of the perylene core were synthesized to investigate the influence of imide-substituent patterns on the aggregation behaviours of PDIs. The photophysical properties of these PDIs were studied by UV-Vis absorption, fluorescence and time-resolved photoluminescence spectroscopy. The differences in the photophysical properties of the PDIs indicate (i) blue-shifted and broadening absorption properties in both solution and thin-films, (ii) red-shifted and broadening fluorescence behavior at their emission maximum in solution, however, blue-shifted fluorescence behavior in thin-films, and (iii) obviously longer fluorescence life-times corresponding to the existence of rotationally displaced H-type aggregates. The formation of short-range ordered rod-like microstructures through face-to-face alignment of columnar rectangular H-type PDI aggregates was rationalized by scanning electron microscopy. The X-ray diffraction study revealed that the formation of well-defined columnar rectangular (Col_rp) H-type PDI aggregates indicated a nearly constant intracolumnar stacking distance of ∼3.9 Å for all PDIs. All of these findings were consistent with the formation of hydrophobic/hydrophilic interactions between the imide-substituents in addition to the strong hydrophobic π-π stacking interactions between the conjugated perylene cores, which were enforced in the H-type PDI aggregates that spontaneously self-organized into Col_rp structures.

Library of Azabenz-Annulated Core-Extended Perylene Derivatives with Diverse Substitution Patterns and Tunable Electronic and Optical Properties

Here, we present a collection of different azabenz-annulated perylene derivatives. By developing new synthetic strategies and improving existing protocols, we have expanded the structural diversity of these dye molecules to a multifunctional class of ligating chromophores. The Pictet-Spengler (PS) reaction of 1-amino-perylenes with different aldehydes is used to modify the terminal substitution pattern. PS transformations of 1,6- and/or 1,7-diamino perylenes result in 2-fold annulated nitrogen-containing coronene-type molecules like anti-(ab)2-PBI 15, syn-(ab)2-PBI 16, and syn-(ab)2-PTE 18. In addition, azabenz-annulated perylene bisanhydrides (ab-PBA 6 and syn-(ab)2-PBA 19) were explored as universal starting materials providing access to any desired imide functionality. Furthermore, a newly developed regioselective nitration procedure for perylene monoimide diesters (PMIDE) enables the synthesis of 1-nitro-PMIDE 10 and thus of azabenz-annulated perylene derivatives with unsymmetric peri-substitution patterns (ab-PMIDE 12 and ab-PMIMA 13). According to our spectroscopic and theoretical investigations, the optical and electrochemical properties of these multifunctional chromophores can easily be modified and adjusted to many desirable applications following the synthetic strategies presented in this work.

1,6- and 1,7-Regioisomers of Highly Soluble Amino-Substituted Perylene Tetracarboxylic Dianhydrides: Synthesis, Optical and Electrochemical Properties

1,6- and 1,7-regioisomers of diamino-substituted perylene tetracarboxylic dianhydrides (PTCDs) with different n-alkyl chain lengths (n = 6, 12 or 18) were synthesized and characterized by NMR spectroscopy and high-resolution mass spectrometry. These dyes are highly soluble in most organic solvents and even in nonpolar solvents, such as hexane. To the best of our knowledge, this is the first time the 1,6-diamino-substituted PTCDs (2a-2c) have been obtained in pure form. The regioisomers 1a-1c (1,7-) and 2a-2c (1,6-) exhibit significant differences in their optical characteristics. In addition to the longest wavelength absorption band at around 674 nm, 2a-2c exhibit another shoulder band at ca. 600 nm, and consequently, cover a large part of the visible region relative to those of 1a-1c. Upon excitation, 2a-2c also show larger dipole moment changes than those of 1a-1c; the dipole moments of all compounds have been estimated using Lippert-Mataga equation. Moreover, all the dyes show a unique charge transfer emission in the near-infrared region, of which the peak wavelengths exhibit strong solvatochromism. They all exhibit one irreversible one-electron oxidation and two quasi-reversible one-electron reductions in dichloromethane at modest potentials. Complementary density functional theory calculations performed on these chromophores are reported in order to rationalize their electronic structure and optical properties.

Selectively detecting trace picric acid by reduced perylene bisimide with POSS substituents and their nanoaggregates

Reduced perylene bisimides (PBIs) with two substituents of polyhedral oligomeric silsesquioxane (POSS) are designed and synthesized for rapid and selective detection of picric acid in THF solution.