Search Results (20)

Annulated organic molecular structures with planar, fused backbones exhibit superior properties compared to non-fused systems, including high crystallinity, strong π–π stacking, and excellent charge transport characteristics. The rational design of annulated compounds with targeted characteristics presents a significant challenge that requires a comprehensive understanding of structure–property relationships. This work addresses this by synthesizing a series of novel push–pull systems featuring benzothieno[3,2-b]benzothiophene (BT) or its nitrogen-rich analogue, indolo[3,2-b]indole (ID), as electron-donating units, connected via a phenylene π-spacer to two distinct electron-accepting groups (carbonyl or dicyanovinyl). The thermal, structural, optical and electrochemical properties of these compounds were thoroughly investigated. Computational studies of the optical and electrochemical properties, including those of unsubstituted ID and BT model cores, showed excellent agreement with experimental data, validating the theoretical models. Notably, ID-based derivatives exhibited remarkably high photoluminescence quantum yield and enhanced solubility compared to their BT counterparts, along with thermal properties that are more favorable for device fabrication. This work provides the first systematic comparison of these annulated cores, offering novel structure–property insights that may support the rational design of organic functional materials and contribute to the further development of organic electronics. Full article

Two new species of free-living marine nematodes from mangrove wetlands of Beihai, Guangxi province in China, are described and illustrated. Trissonchulus sinensis sp. nov. is characterized by a head continuous with the body, an amphidial fovea pouch-shaped, pharynx expanding gradually but not forming a posterior bulb, spicules sclerotized, blade-shaped, slightly curved ventrally, proximal part enlarged with a prominent central septum, posterior part slender and handle-like; gubernaculum small, composed of two distally connected sheet-like structures with tooth-like ends, and lacking apophysis. Metachromadora sinica sp. nov. is characterized by a cuticle that is finely annulated, labial sensilla papilliform, cephalic setae four in number, amphideal fovea loop-shaped, exhibiting a double-contoured appearance, pharyngeal bulb well-developed, internal cuticular lumen tripartite, lateral epidermal ridges present, spicules slender with an enlarged capitulum, gubernaculum boat-shaped, precloacal supplements absent, tail conical with two setose protuberances, three pairs of subventral preanal setae, and a pair of papillae situated anterior to the anus. Nearly full-length SSU sequences and D2-D3 of LSU sequences are provided for the new species. Phylogenetic analysis of SSU provided support for the current classification status of the two new species. In the SSU phylogenetic tree, the family Ironidae was recovered as a separate monophyletic clade. However, the phylogenetic relationships within the family Desmodoridae were complicated, and the subfamilies Desmodorinae and Spiriniinae were polyphyletic. A comprehensive taxonomic approach combining morphological observations and molecular phylogeny construction would be particularly valuable in a more robust nematode taxonomy. Full article

Hypoxia and activation of the pentose phosphate pathway (PPP), as well as overexpression of glucose-6-phosphate dehydrogenase (G6PD), are hallmark features of glioblastomas (GBM), contributing significantly to tumor progression metabolic adaptation and drug resistance. This study aimed to evaluate the cytotoxic effects of nine synthetic compounds incorporating annulated benzimidazole and nitrothiazole scaffolds in two glioblastoma cell lines (A172 and U87-MG) under both normoxic and hypoxic conditions. Three compounds (BZM-7, BZM-9, and CNZ-3) demonstrated potent anticancer activity, with CNZ-3 exhibiting the highest efficacy, particularly in hypoxia. The study further investigated the effects of these compounds on the expression of the G6PD gene, as well as post-translational regulatory genes SIRT2 and KAT9, and the angiogenesis-related VEGF gene. Transcriptional analyses showed that the nitrothiazole-derived compound CNZ-3 significantly downregulated G6PD, SIRT2, KAT9 and VEGF expression under hypoxic conditions, suggesting selective interference with hypoxia-adaptative pathways. In contrast, BZM-7 and BZM-9 showed distinct expression patterns, indicating diverse mechanisms of action despite structural similarity. In addition, BZM-7, BZM-9, and CNZ-3 were identified as potent inhibitors of recombinant G6PD, demonstrating both enzymatic inhibition and structural alterations, suggesting that G6PD could be a relevant therapeutic target for these compounds. Furthermore, molecular docking analysis revealed favorable binding interactions between the compounds and key amino acids of the G6PD, reinforcing their potential as a direct enzyme inhibitors. These findings highlight the pivotal role of G6PD in gliomas under hypoxic conditions and support its inhibition as a promising therapeutic strategy. Full article

Background/Objectives: Oxidative stress, the Warburg effect, and resistance to apoptosis are key hallmarks driving colorectal tumorigenesis. This study aimed to develop novel multi-target compounds capable of modulating these pathways. Methods: A library of 24 newly synthesized compounds—incorporating annulated thiophene, thiazole, quinazolinone, 2-oxoindoline, and 1,2,3-oxadiazole scaffolds, as well as N-(1-(4-hydroxy-3-methoxyphenyl)-3-oxo-3-(2-(phenylcarbamothioyl)hydrazineyl) prop-1-en-2-yl)benzamide—was evaluated for antioxidant activity (DPPH assay), PDK-1 and LDHA inhibition, cytotoxic effects against LoVo and HCT-116 colon carcinoma cells, with parallel assessment of safety profiles on normal HUVECs. The underlying anticancer mechanism of the most active compound was investigated through analysis of cell cycle distribution, apoptosis induction, intracellular reactive oxygen species levels, mitochondrial membrane potential disruption, and expression levels of apoptosis-related genes. Molecular docking assessed binding interactions within LDHA and PDK-1 active sites. The physicochemical, drug-likeness, and ADMET properties of the multi-bioactive candidates were predicted in silico. Results: Among the synthesized compounds, thiophenes 3b and 3d exhibited potent PDK-1/LDHA and DPPH/LDHA inhibitions, along with significant cytotoxic effects on LoVo/HCT-116 cells (IC₅₀ in µM: 190.30/170.21 and 156.60/160.96, respectively), while showing minimal cytotoxicity toward HUVECs. Molecular docking revealed favorable interactions with key amino acid residues within the LDHA and/or PDK-1 active sites. Compound 3d notably induced G2/M (LoVo) and G1 (HCT-116) arrest and promoted apoptosis via enhancing ROS generation, modulating Bax/Bcl-2 expressions, disrupting mitochondrial membrane potential, and ultimately activating caspses-3. In silico predictions indicated their promising drug-likeness and pharmacokinetics, though high lipophilicity, poor solubility (especially for 3b), and potential toxicity risks were identified as limitations. Conclusions: Thiophenes 3b and 3d emerged as promising multi-target candidates; however, structural optimization is warranted to enhance their solubility, bioavailability, and safety to support further development as lead anti-colon cancer agents. Full article

Azulene-based polycyclic hydrocarbons have garnered much attention as potential materials for organic optoelectronic devices and as molecular models for graphene nanosheets with structural defects. Although various methods for ring fusions to an azulene core have been established for ring fusions to an azulene core, efficient synthetic methodologies for ortho- and peri-fusion to an azulene core are still lacking, which hinders the investigation of the effect of the ortho- and peri-fusion on the electronic properties of the embedded azulene core. Herein, we describe the synthesis and characterization of quinoxaline-fused cyclopenta[cd]azulene 4 as a new ortho- and peri-fused azulene derivative. The target molecule 4 was successfully synthesized in four steps from 4-methylazulene. The ring annulation decreased the lowest excitation energy compared with that of azulene and its structural isomer 5 and led to multiple reversible reduction processes. Characterization of the molecular geometry and optoelectronic properties of 4 revealed that the embedded azulene core preserves its original aromaticity, while the fused quinoxaline acts as a nucleophilic and basic site. These features suggest that 4 could serve as a metal ligand, a near-infrared absorber, and a component in organic functional devices. Full article

Using quantum chemical calculation data obtained by the DFT method with the B3PW91/TZVP and M062X/def2TZVP theory levels, the possibility of the existence of four Be(II) coordination compounds, each of which contains in the inner coordination sphere and the double deprotonated forms of subporphyrazine (H₂SP), mono[benzo]subporphyrazine (H₂MBSP), di[benzo]subporphyrazine (H₂DBSP), and tri[benzo]subporphyrazine (subphthalocyanine) (H₂TBSP) with a ratio Be(II) ion/ligand = 1:1, were examined Selected geometric parameters of the molecular structures of these (666)macrotricyclic complexes with closed contours are given; it was noted that BeN3 chelate nodes have a trigonal–pyramidal structure and exhibit a very significant (almost 30°) deviation from coplanarity; however, all three 6-membered metal-chelate and three 5-membered non-chelate rings in each of these compounds are practically planar and deviate from coplanarity by no more than 2.5°. The bond angles between two nitrogen atoms and a Be atom are equal to 60° (in the [BeSP] and [BeTBSP]) or less by no more than 0.5° (in the [BeMBSP] and [BeDBSP]). The presence of annulated benzo groups has little effect on the parameters of the molecular structures of these complexes. Good agreement between the structural data obtained using the above two versions of the DFT method was noticed. NBO analysis data for these complexes are presented; it was noted that, according to both DFT methods used, the ground state of the each of complexes under study is a spin singlet. Standard thermodynamic parameters of formation (standard enthalpy Δ_fH⁰, entropy S⁰, and Gibbs free energy Δ_fG⁰) for the above-mentioned macrocyclic compounds were calculated. Full article

This work aimed to develop organic photocatalysts (PCs) that could mediate organocatalytic atom transfer radical polymerization (O-ATRP) under visible light. Through the core-modification of known chromophoric structures and ring-locking to reach a conjugation extension, annulated N-aryl benzo[kl]acridines were identified as effective visible light-responsive photocatalysts. The corresponding selenium-doped structure showed excellent performance in the O-ATRP of methacrylates, which could afford polymer products with controlled molecular weights and low dispersities under the irradiation of visible light at a 100 ppm catalyst loading. Full article

Two series of novel [1,2,4]triazolo[4,3-c]- and [1,2,4]triazolo[1,5-c]quinazoline fluorophores with 4′-amino[1,1′]-biphenyl residue at position 5 have been prepared via Pd-catalyzed cross-coupling Suzuki–Miyaura reactions. The treatment of 2-(4-bromophenyl)-4-hydrazinoquinazoline with orthoesters in solvent-free conditions or in absolute ethanol leads to the formation of [4,3-c]-annulated triazoloquinazolines, whereas [1,5-c] isomers are formed in acidic media as a result of Dimroth rearrangement. A 1D-NMR and 2D-NMR spectroscopy, as well as a single-crystal X-ray diffraction analysis, unambiguously confirmed the annelation type and determined the molecular structure of p-bromophenyl intermediates and target products. Photophysical properties of the target compounds were investigated in two solvents and in the solid state and compared with those of related 3-aryl-substituted [1,2,4]triazolo[4,3-c]quinazolines. The exclusion of the aryl fragment from the triazole ring has been revealed to improve fluorescence quantum yield in solution. Most of the synthesized structures show moderate to high quantum yields in solution. Additionally, the effect of solvent polarity on the absorption and emission spectra of fluorophores has been studied, and considerable fluorosolvatochromism has been stated. Moreover, electrochemical investigation and DFT calculations have been performed; their results are consistent with the experimental observation. Full article

The construction of high-performance n-type semiconductors is crucial for the advancement of organic electronics. As an attractive n-type semiconductor, molecular systems based on perylene diimide derivatives (PDIs) have been extensively investigated over recent years. Owing to the fascinating aggregated structure and high performance, S-heterocyclic annulated PDIs (SPDIs) are receiving increasing attention. However, the relationship between the structure and the electrical properties of SPDIs has not been deeply revealed, restricting the progress of PDI-based organic electronics. Here, we developed two novel SPDIs with linear and dendronized substituents in the imide position, named linear SPDI and dendronized SPDI, respectively. A series of structural and property characterizations indicated that linear SPDI formed a long-range-ordered crystalline structure based on helical supramolecular columns, while dendronized SPDI, with longer alkyl side chains, formed a 3D-ordered crystalline structure at a low temperature, which transformed into a hexagonal columnar liquid crystal structure at a high temperature. Moreover, no significant charge carrier transport signal was examined for linear SPDI, while dendronized SPDI had a charge carrier mobility of 3.5 × 10⁻³ cm² V⁻¹ s⁻¹ and 2.1 × 10⁻³ cm² V⁻¹ s⁻¹ in the crystalline and liquid crystalline state, respectively. These findings highlight the importance of the structure–function relationship in PDIs, and also offer useful roadmaps for the design of high-performance organic electronics for down-to-earth applications. Full article

Dehydrohelicene-based molecules stand out as highly promising scaffolds and captivating chiroptical materials, characterized by their unique chirality. Their quasi-helical π-conjugated molecular architecture, featuring successively ortho-annulated aromatic rings, endows them with remarkable thermal stability and optical properties. Over the past decade, diverse approaches have emerged for synthesizing these scaffolds, reinvigorating this field, with anticipated increased attention in the coming years. This review provides a comprehensive overview of the historical evolution of dehydrohelicene chemistry since the pioneering work of Zander and Franke in 1969 and highlights recent advancements in the synthesis of various molecules incorporating dehydrohelicene motifs. We elucidate the intriguing structural features and optical merits of these molecules, occasionally drawing comparisons with their helicene or circulene analogs to underscore the significance of the bond between the helical termini. Full article

1,3-butadiynamides—the ethynylogous variants of ynamides—receive considerable attention as precursors of complex molecular scaffolds for organic and heterocyclic chemistry. The synthetic potential of these C4-building blocks reveals itself in sophisticated transition-metal catalyzed annulation reactions and in metal-free or silver-mediated HDDA (Hexa-dehydro-Diels–Alder) cycloadditions. 1,3-Butadiynamides also gain significance as optoelectronic materials and in less explored views on their unique helical twisted frontier molecular orbitals (Hel-FMOs). The present account summarizes different methodologies for the synthesis of 1,3-butadiynamides followed by the description of their molecular structure and electronic properties. Finally, the surprisingly rich chemistry of 1,3-butadiynamides as versatile C4-building blocks in heterocyclic chemistry is reviewed by compiling their exciting reactivity, specificity and opportunities for organic synthesis. Besides chemical transformations and use in synthesis, a focus is set on the mechanistic understanding of the chemistry of 1,3-butadiynamides—suggesting that 1,3-butadiynamides are not just simple alkynes. These ethynylogous variants of ynamides have their own molecular character and chemical reactivity and reflect a new class of remarkably useful compounds. Full article

This work covers the development of non-fullerene acceptors for use in organic photovoltaics built using the N-annulated perylene diimide dye. The classic perylene diimide dye has been extensively used to construct non-fullerene acceptors, leading to device power conversion efficiencies of over 10%. Strong visible light absorption and deep frontier molecular energy levels have made such materials (both molecular and polymeric) near ideal for pairing with narrow-gap conjugated polymers in bulk-heterojunction active layers. The N-annulation of the dye provides an extra site for side-chain engineering and alters the electronic structure of the polycyclic aromatic core. In addition, N-annulation allows for selective bromination of the perylene core, leading to building blocks that are useful for the construction of large molecular frameworks using the atom-economical direct heteroarylation cross-coupling method. Herein, we detail a series of molecules developed by our team that are based on the N-annulated perylene diimide in the form of dimers with different cores (both electron-rich and electron-deficient); dimers with varied side chains; tetramers with varying geometries; and large, asymmetric molecules with internal energy cascades. The use of these molecules as non-fullerene acceptors in organic photovoltaic devices (binary and ternary blends, outdoor and indoor light applications, and spin-coated vs. slot-die-coated photoactive layers) is presented. Full article

Based on the structures of natural products streptochlorin and pimprinine derived from marine or soil microorganisms, a series of streptochlorin derivatives containing the nitrile group were designed and synthesized through acylation and oxidative annulation. Evaluation for antifungal activity showed that compound 3a could be regarded as the most promising candidate—it demonstrated over 85% growth inhibition against Botrytis cinerea, Gibberella zeae, and Colletotrichum lagenarium, as well as a broad antifungal spectrum in primary screening at the concentration of 50 μg/mL. The SAR study revealed that non-substituent or alkyl substituent at the 2-position of oxazole ring were favorable for antifungal activity, while aryl and monosubstituted aryl were detrimental to activity. Molecular docking models indicated that 3a formed hydrogen bonds and hydrophobic interactions with Leucyl-tRNA Synthetase, offering a perspective for the possible mechanism of action for antifungal activity of the target compounds. Full article

Benzothioxanthene imide (BTI) has recently emerged as an interesting and promising block for organic electronics. In this contribution, we report on the impact of the N-annulation of the latter dye on the optoelectronic of π-extended molecular structures. To do so, the thiophene-diketopyrrolopyrrole was selected, as central π-conjugated core, and either end-capped with two BTIs or its N-annulated version, namely the TCI. While almost similar band gaps were measured for individual rylene imide dyes, significant differences were highlighted, and rationalized, on their π-extended counterparts. Full article

For the first time, 5-formyl-1-(pyridin-3-yl)-1H-1,2,3-triazole-4-carboxylate was synthesized via a two-step scheme. The molecular structure of the compound was determined by a single-crystal X-ray diffraction analysis. The Hirshfeld surface analysis was used to study various intermolecular interactions. The crystalline structure is marked by the presence of three types of π-interactions (n→π*, lp···π, and π···π) between the -C(H)=O group and triazole rings. The compound is a versatile polyfunctional building block for construction of annulated 1,2,3-triazoles. Full article