Improved synthesis of tetraaryl-1,4-dihydropyrrolo[3,2-b]pyrroles a promising dye for organic electronic devices: An experimental and theoretical approach

Abstract

Pyrrolo-[3,2-b]pyrroles represent a class of promising materials for application in organic electronics with interesting optoelectronic properties and great synthesis versatility, but yields obtained from varied synthetic routes are still very low, hindering their effective application for industrial purposes. In this report, we present a method for the synthesis of tetraaryl-1,4-dihydropyrrolo-[3,2-b]pyrrole derivatives by multicomponent reactions employing niobium pentachloride as a catalyst. The optical characterization of the products is also presented. Electronic structure calculations were performed to help the interpretation of the synthesis process, as well as the optical properties of the systems. Excellent yields and low reaction times were obtained, indicating that NbCl 5 is an efficient catalyst for such systems. The products show promising properties for optoelectronic applications that can be adjusted by the choice of benzaldehyde derivatives used in the synthesis.

The Antioxidant Peptide Salamandrin-I: First Bioactive Peptide Identified from Skin Secretion of Salamandra Genus (Salamandra salamandra)

“…In order to understand the antioxidant activity-structure relationship of salamandrin-I, electronic properties of the peptide were investigated and compared with glutathione and Trolox, whose structures are presented in Figure 4A-C. Figure 4D,E show the relative position of the frontier orbitals (HOMO: highest occupied molecular orbital and LUMO: lowest unoccupied molecular orbital), as well as the DAM associated with these compounds and other common antioxidants [55]. Note that salamandrin-I, glutathione, and Trolox present similar frontier energy levels, which suggests that these compounds have analogue electron acceptor/donor properties.…”

“…In general, these indexes indicate which sites are prone to interact with electrophiles (f − ), nucleophiles (f + ), or free radicals (f 0 ). The stick graphs represent the local softness of the antioxidants (AOX) in relation to the ROS species (H 2 O 2 , HOO • and OH • ), and according to the hard and soft acids and bases (HSAB) principle, chemical reactions are supposed to occur more effectively between atoms with comparable chemical softness [55]. Once the compounds' activity was associated with their oxidant/reductive properties, the plausibility was investigated of salamandrin-I, glutathione and Trolox to act as: i) electrophiles (for AOX reduction: s + /s − ), ii) nucleophiles (for AOX oxidation: s − /s + ), and iii) free-radicals (s 0 /s 0 ).…”

Acetylated cashew gum-based nanoparticles for the incorporation of alkaloid epiisopiloturine

“…Such indexes describe how the electronic populations of the atoms change after the releasing/withdrawing of electrons in/from a given system, allowing to identify molecular sites that are prone to interact with nucleophiles (f + ) or electrophiles (f − ) [31]. In particular, these descriptors have been successfully employed in the study of polymers [[32], [33], [34], [35]] and molecules reactivity [11,27,31,36,37]. The simulations were carried out in vacuo and without temperature effects using the same DFT/B3LYP/6-31G approach employed in the optimizations.…”

“…The simulations were carried out in vacuo and without temperature effects using the same DFT/B3LYP/6-31G approach employed in the optimizations. Hirshfeld partition charge model was employed to estimate the electronic populations to avoid negative CAFIs [ [31], [32], [33], [34], [35]].…”

Multicomponent reactions mediated by NbCl 5 for the synthesis of phthalonitrile-quinoline dyads: Methodology, scope, mechanistic insights and applications in phthalocyanine synthesis

“…However, they are not always cost competitive nor easily scaled up. As part of our research interests on synthetic methodologies using NbCl 5 [40][41][42][43][44][45][46][47][48][49][50], we report a new approach for the functionalization of 4formylphthalonitrile (1) with substituted anilines and terminal phenylacetylenes via a multicomponent reaction (MCR) promoted by NbCl 5 in the presence of p-chloranil.…”