Benzene Moiety Research Articles

Design and Synthesis of Multipath Compact Cyclophanes for Quantum Interference Studies

To investigate interference phenomena and con­duc­tance properties in mechanically controlled break junctions (MCBJs), macrocycles 1 and 2 (BMCs: for BenzeneMacroCycles), containing a meta‐substituted benzene moiety with solubilizing tert‐butyl groups, as well as structures 3 and 4 (TMCs: for ThiopheneMacroCycles), featuring 2,5‐connected 3,4‐hexyl‐thio­phene corners, were synthesized. Macrocycles 1 and 2 respect­ively 3 and 4 differ in the positions of the acetyl‐protected sulfur anchoring groups, which impacts both, the individual transport efficiency of their parallel electronic pathways and their overall molecular wire lengths. All macrocycles were synthesized based on a series of Sonogashira cross‐coupling reactions. For 3 and 4, a 2‐(4‐pyridin­yl)ethyl protecting group for the sulfur atoms was successful, while for macrocycles 1 and 2 the more common tert‐butyl protecting group did the job. To our delight, proof‐of‐concept charge transport studies conducted in an MCBJ setup demon­strated the expected trends regarding improved conductance intensities for the TMCs compared to the BMCs. Furthermore, the corres­ponding molecular plateaus from the breaking experiments were in the expected length range of the S‐S distances for all compounds. We also found that the overall conductance seems to follow a more complex transport mechanism than just the sum of contributions from both channels.

Novel Bis(4-aminophenoxy) Benzene-Based Aramid Copolymers with Enhanced Solution Processability.

Aramid copolymers have garnered significant interest due to their potential applications in extreme environments such as the aerospace, defense, and automotive industries. Recent developments in aramid copolymers have moved beyond their traditional use in high-strength, high-temperature resistant fibers. There is now a demand for new polymers that can easily be processed into thin films for applications such as electrical insulation films and membranes, utilizing the inherent properties of aramid copolymers. In this work, we demonstrate two novel aramid copolymers that are capable of polymerizing in polar organic solvents with a high degree of polymerization, achieved by incorporating flexible bis(4-aminophenoxy) benzene moieties into the chain backbone. The synthesized MBAB-aramid and PBAB-aramid have enabled the fabrication of exceptionally thin, clear films, with an average molecular weight exceeding 150 kDa and a thickness ranging from 3 to 10 μm. The dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) reveal that the thin films of MBAB-aramid and PBAB-aramid exhibited glass transition temperatures of 270.1 °C and 292.7 °C, respectively, and thermal decomposition temperatures of 449.6 °C and 465.5 °C, respectively. The mechanical tensile analysis of the 5 μm thick films confirmed that the tensile strengths, with elongation at break, are 107.1 MPa (50.7%) for MBAB-aramid and 113.5 MPa (58.4%) for PBAB-aramid, respectively. The thermal and mechanical properties consistently differ between the two polymers, which is attributed to variations in the linearity of the polymer structures and the resulting differences in the density of intermolecular hydrogen bonding and pi-pi interactions. The resulting high-strength, ultra-thin aramid materials offer numerous potential applications in thin films, membranes, and functional coatings across various industries.

Peripheral substituent effect on ‘turn-on’ fluorescence of BODIPY derivatives for sensing benzene moieties

In this work, a series of dipyrrometheneboron difluoride (BODIPY) derivatives, BT-F, BT-H, and BT-OMe, was prepared to study the peripheral substituent effect on 'turn-on' fluorescent for benzene moieties including benzene, toluene, and xylene (BTX). The photophysical- and electrochemical properties of the three compounds were systematically studied by steady-state UV–visible and PL spectroscopies, and cyclic voltammetry along with DFT calculations. Among various organic solvents, all compounds selectively showed strong 'turn-on' fluorescence in BTX solvents, proving that these compounds can be used as BTX probes. As the portion of BTX increases, the emission band shows a hypsochromic shift, indicating that the enhanced emission originated from exciplex formation in the excited state. Among them, BT-OMe, which has methoxy groups at peripheral positions, showed the highest sensing capability to BTX. The electron-donating nature of the methoxy group enhances the electron population on the BODIPY core and the triphenylamine groups, which results in strong interaction with BTX in the excited state.

Rationale design and synthesis of new roflumilast analogues as preferential selective and potent PDE-4B inhibitors

In this study, we designed and synthesized novel analogues of roflumilast that exhibit selective inhibition of PDE-4B. To accomplish this target; synthesis of novel series (4a-u, 5a-i, and 6) was done, aiming at obtaining new PDE-4B inhibitors hits based on the proposed pharmacophore, 1-(cyclopropylmethoxy)-2-(difluoromethoxy) benzene moiety. Enzyme assay was used to measure the IC50 values for the PDE-4B inhibition of all the synthesized compounds along with roflumilast as a reference drug. The results demonstrated that most of the examined candidates exhibited considerable inhibitory activity against the PDE-4B enzyme. The four compounds (4i, 4k, 4p, and 4q) exhibited the highest potency (IC50 = 7.25, 7.15, 5.50, 7.19 nM, respectively) with no significant inhibition difference from roflumilast (no statistical difference at p < 0.05). Interestingly, compound 4p with 3-OH and 4-OCH3 substituents was found to be the most potent against PDE-4B enzyme (IC50 = 5.50 nM), compared to that of roflumilast (IC50 = 2.36 nM). Moreover, the most potent derivatives 4i, 4k, 4p, and 4q were further tested for PDE-4D inhibitory activity to investigate their PDE-4D/PDE-4B selectivity ratio. Compound 4k showed the highest selectivity towards PDE-4B isozyme more than the reference drug roflumilast (PDE-4D/4B IC50 ratio for compound 4k and roflumilast = 3.22 and 3.02, respectively). Additionally, compound 4p was chosen to test its selectivity for PDE-4B over PDE-8A, PDE-11A, and PDE-1B compared to thereference drug roflumilast. Compound 4p showed approximately 6-fold selectivity for PDE-4B over PDE-8A, about 5-fold selectivity for PDE-4B over PDE-11A, and 11-fold selectivity of PDE-4B over PDE-1B. Compound 4p showed a higher selectivity towards PDE-4B than PDE-1B, more than the reference compound roflumilast. Furthermore, the most potent compounds (4i, 4k, 4p, 4q) were subjected to further investigation, and their effects on the cAMP level and percentage of inhibition of tumor necrosis factor-alpha (TNF-α) were studied and compared with reference drug roflumilast. Compound 4q showed the highest increase in the level of intracellular cAMP (6.55 ± 0.37 pmol/mL) and compound 4i showed the highest % of TNF-α inhibition (77.22 %). On the other side, a molecular docking study against PDE-4B clarified that all the examined candidates achieved nearly similar binding modes with similar orientations to that of the native roflumilast ligand and showed higher docking scores than roflumilast.

Consciousness: a quantum optical effect in fluorescent protein pathways

This paper presents a physical mechanism of embodied consciousness based on the dynamic organicity theory. We use the entropic pilot wave theory to describe the quantum dipole oscillations from dipole-bound delocalized (quasi-free) electrons in nonpolar nanocavities of aromatic amino acid residues (benzene moiety /cyclic hydrocarbons that contain resonance structures) and their fluorescent pathways. These pathways contain cavity quasipolariton condensates composed of quantized polarization waves of entangled photons. The behavior of oscillating molecular dipoles is influenced by the quantum nature of dynamic organicity, which causes energy fluctuations necessary to move delocalized electrons and create bare polaritons (quantized polarization waves). These waves correspond to photon quasiparticles interacting with water molecules to form quasipolaritons, softened by interacting with hydroxide ions (OH-) within crystal lattices of interfacial water H30. When [H3O+]=[OH−], the solution is neutral in hydrophobic nanocavities. In such nonpolar cavities, evanescent photons (non-radiative transitions in the absence of any source) are emitted while protons (H+) diffuse due to recombination with hydroxide (OH-) ions, acting as protonic analogs of ‘holes’ or excitons. In protein pores, proton motion strongly coupled with π-electron delocalization is a conduit for exciton-photon (polariton) and its polarization wave component. Internal energy fluctuations comprise both quantum potential energy and negative quantum kinetic energy. We explore how quantum potential energy influences the negentropic effect of a 'repulsive force' guided by entropic pilot waves through pilot wave force (negentropic force), functioning as an information-based action of the polarization wave as a conduit of the cavity quasipolariton. When the rate of change of quantum entropy is zero, and momentum of the polarization wave is zero the internal energy transduction between quantum potential energy to quantum kinetic energy manifests as the negentropic force and facilitates the movement of information-based action for information encoding when negative quantum kinetic energy happens at certain times. Experiments have shown that biphoton entanglement interferes with anaesthetics. We postulate that the disruption of cavity polaritonic condensate through its polarization wave component disrupts the decoding of information, suggesting consciousness is attributed to a quantum optical effect. Therefore, we further theorize that consciousness is attributed to the negative quantum kinetic energy of the polarization wave, which provides an informational structure of multiscale redundancy when negentropic action reduces information redundancy. This has profound implications for understanding consciousness as nonmechanical action channeled through negentropic force when the rate of change of quantum entropy is zero.

Enantioselective Synthesis, Crystal Structures, and Stereoisomerism of Substituted o,m,o,p-Tetraphenylenes.

We have achieved the enantioselective synthesis of highly strained, substituted o,m,o,p-tetraphenylenes (≤98% ee) via the cationic Rh(I)/(R)-H8-BINAP complex-catalyzed chemo-, regio-, and enantioselective intermolecular cross-[2+2+2] cycloaddition of teraryl diynes with dimethyl acetylenedicarboxylate. X-ray crystallographic analyses demonstrate the highly bent structures of the para-substituted benzene moieties, and density functional theory calculations reveal the large local strain of the paraphenylene unit. 1H nuclear magnetic resonance analyses and theoretical calculations elucidate the stereoisomerism, indicating that the nonrotatable ortho-disubstituted biphenyl structure results in cis and trans isomers.

Conformation and Photodissociation Process of Benzo-15-Crown-5 and Benzo-18-Crown-6 Complexes with Ammonium Ions Investigated by Cold UV and IR Spectroscopy in the Gas Phase.

We examined the conformation of benzo-15-crown-5 (B15C5) and benzo-18-crown-6 (B18C6) complexes with ammonium ions, NH4+, CH3NH3+ (MeNH3+), CH3CH2NH3+ (EtNH3+), and CH3CH2CH2NH3+ (PrNH3+), using cold UV and IR spectroscopy in the gas phase. We measured the UV photodissociation (UVPD) spectra of the ammonium complexes and compared them with those of the K+(B15C5) and K+(B18C6) complexes in order to identify the conformation on the basis of the band position. The number of possible conformations for the ammonium complexes of B15C5 is limited compared with alkali metal ions with similar ionic radii. The NH4+(B15C5), MeNH3+(B15C5), and EtNH3+(B15C5) complexes show two conformers, whereas the K+(B15C5) complex has three stable conformers. In the case of the PrNH3+(B15C5) complex, one conformer was found predominantly in the UVPD spectrum. The ammonium complexes of B15C5 prefer to adopt crown conformations with large dihedral angles on the C-O-C-C atoms around the benzene moiety. In the case of the ammonium complexes of B18C6, two or three conformers were found in the UVPD spectra. One conformation of the B18C6 complexes is similar to that of the K+(B18C6) complex, which has a planar form on the C-O-C-C atoms around the benzene moiety. The other but dominant conformations of the ammonium complexes could be attributed to those with large C-O-C-C dihedral angles. These conformational findings for the ammonium complexes suggest that the benzo-crown ethers tend to adopt nonplanar conformations around the benzene moiety to encapsulate the ammonium ions. The IR-UV double-resonance (DR) spectra of the B15C5 and B18C6 complexes were compared to those of benzo-12-crown-4 (B12C4) and dibenzo-18-crown-6 (DB18C6) complexes. The N-H···O hydrogen bond (H-bond) is weaker with increasing ring size from B12C4 to B18C6, although the calculated binding energy is smaller for B12C4 than for B18C6. This result indicates that cooperative H-bonds with three N-H groups can strengthen the intermolecular bond between the ammonium ions and B18C6. The difference in the conformational preference between the ammonium and K+ complexes is attributed to directed N-H···O H-bonds in the ammonium complexes. Proton transfer and dissociation of the crown ring were also observed for the photoexcitation of the NH4+(B15C5) and NH4+(B18C6) complexes.

Electron-Beam-Induced Modification of N-Heterocyclic Carbenes: Carbon Nanomembrane Formation.

Electron irradiation of self-assembled monolayers (SAMs) is a versatile tool for lithographic methods and the formation of new 2D materials such as carbon nanomembranes (CNMs). While the interaction between the electron beam and standard thiolate SAMs has been well studied, the effect of electron irradiation for chemically and thermally ultrastable N-heterocyclic carbenes (NHCs) remains unknown. Here we analyze electron irradiation of NHC SAMs featuring different numbers of benzene moieties and different sizes of the nitrogen side groups to modify their structure. Our results provide design rules to optimize NHC SAMs for effective electron-beam modification that includes the formation of sulfur-free CNMs, which are more suitable for ultrafiltration applications. Considering that NHC monolayers exhibit up to 100 times higher stability of their bonding with the metal substrate toward electron-irradiation compared to standard SAMs, they offer a new alternative for chemical lithography where structural modification of SAMs should be limited to the functional group.

New Analogues of the Nicotinamide Phosphoribosyltransferase Inhibitor FK866 as Potential Anti-Pancreatic Cancer Agents.

During the past two decades, many nicotinamide phosphoribosyltransferase (NAMPT) inhibitors were prepared and tested because this enzyme is overexpressed in pancreatic cancer. Although FK866 is a well-known, strong NAMPT inhibitor, it suffers severe drawbacks. Our work aimed to synthesize efficient NAMPT inhibitors featuring better pharmacokinetic properties than the pyridine-containing FK866. To this aim, the new anticancer agents were based on benzene, pyridazine, or benzothiazole moieties as a cap group instead of the pyridine unit found in FK866 and other NAMPT inhibitors. The new compounds, prepared exploiting standard heterocycle chemistry and coupling reactions (e.g., formation of amides, ureas, and cyanoguanidines, copper-mediated azide-alkyne cycloaddition), have been fully characterized using NMR and HRMS analyses. Their activity has been evaluated using cytotoxicity and intracellular NAD depletion assays in the human pancreatic cancer cell line MiaPaCa-2. Among the 14 products obtained, compound 28, bearing a pyridazine unit as the cap group and a thiophene moiety as the tail group, showed 6.7 nanomolar inhibition activity in the intracellular NAD depletion assay and 43 nanomolar inhibition in the MiaPaCa-2 cells cytotoxicity assay, comparable to that observed for FK866. The positive results observed for some newly synthesized molecules, particularly those carrying a thiophene unit as a tail group, indicate that they could act as in vivo anti-pancreatic cancer agents.

1,3,5–2,4,6‐Functionalized Benzene Molecular Cage: An Environmentally Responsive Scaffold that Supports Hierarchical Superstructures

AbstractNew stimulus‐responsive scaffolds are of interest as constituents of hierarchical supramolecular ensembles. 1,3,5–2,4,6‐Functionalized, facially segregated benzene moieties have a time‐honored role as building blocks for host molecules. However, their user as switchable motifs in the construction of multi‐component supramolecular structures remains poorly explored. Here, we report a molecular cage 1, which consists of a bent anthracene dimer 3 paired with 1,3,5‐tris(aminomethyl)‐2,4,6‐triethylbenzene 2. As the result of the pH‐induced ababab↔bababa isomerization of the constituent‐functionalized benzene units derived from 2, this cage can reversibly convert between an open state and a closed form, both in solution and in the solid state. Cage 1 was used to create stimuli‐responsive hierarchical superstructures, namely Russian doll‐like complexes with [K⊂18‐crown‐6⊂1]+ and [K⊂cryptand‐222⊂1]+. The reversible assembly and disassembly of these superstructures could be induced by switching cage 1 from its open to closed form. The present study thus provides an unusual example where pH‐triggered conformation motion within a cage‐like scaffold is used to control the formation and disassociation of hierarchical ensembles.

1,3,5-2,4,6-Functionalized Benzene Molecular Cage: An Environmentally Responsive Scaffold that Supports Hierarchical Superstructures.

New stimulus-responsive scaffolds are of interest as constituents of hierarchical supramolecular ensembles. 1,3,5-2,4,6-Functionalized, facially segregated benzene moieties have a time-honored role as building blocks for host molecules. However, their user as switchable motifs in the construction of multi-component supramolecular structures remains poorly explored. Here, we report a molecular cage 1, which consists of a bent anthracene dimer 3 paired with 1,3,5-tris(aminomethyl)-2,4,6-triethylbenzene 2. As the result of the pH-induced ababab↔bababa isomerization of the constituent-functionalized benzene units derived from 2, this cage can reversibly convert between an open state and a closed form, both in solution and in the solid state. Cage 1 was used to create stimuli-responsive hierarchical superstructures, namely Russian doll-like complexes with [K⊂18-crown-6⊂1]+ and [K⊂cryptand-222⊂1]+. The reversible assembly and disassembly of these superstructures could be induced by switching cage 1 from its open to closed form. The present study thus provides an unusual example where pH-triggered conformation motion within a cage-like scaffold is used to control the formation and disassociation of hierarchical ensembles.

Leveraging Isoreticular Principle to Elucidate the Key Role of Inherent Hydrogen-Bonding Anchoring Sites in Enhancing Water Sorption Cyclability of Zr(IV) Metal-Organic Frameworks.

Water adsorption/desorption cyclability of porous materials is a prerequisite for diverse applications, including atmospheric water harvesting (AWH), humidity autocontrol (HAC), heat pumps and chillers, and hydrolytic catalysis. However, unambiguous molecular insights into the correlation between underlying building blocks and the cyclability are still highly elusive. In this work, by taking advantage of the well-established isoreticular synthetic principle in Zr(IV) metal-organic frameworks (Zr-MOFs), we show that the inherent density of hydrogen atoms in the organic skeleton can play a key role in regulating the water sorption cyclability of MOFs. The ease of isoreticular practice of Zr-MOFs enables the successful syntheses of two pairs of isostructural Zr-MOFs (NU-901 and NU-903, NU-950 and SJTU-9) from pyrene- or benzene-cored carboxylate linkers, which feature scu and sqc topological nets, respectively. NU-901 and NU-950 comprised of pyrene skeletons carrying more hydrogen-bonding anchoring sites show distinctly inferior cyclability as compared with NU-903 and SJTU-9 built of benzene units. Single-crystal X-ray crystallography analysis of the hydrated structure clearly unveils the water molecule-involved interactions with the hydrogen-bonding donors of benzene moieties. Remarkably, NU-903 and SJTU-9 isomers exhibit outstanding water vapor sorption capacities as well as working capacities at the desired humidity range with potential implementations covering indoor humidity control and water harvesting. Our findings uncover the importance of hydrogen-bonding anchoring site engineering of organic scaffold in manipulating the framework durability toward water sorption cycle and will also likely facilitate the rational design and development of highly robust porous materials.

Tension Induced Photoluminescence Enhancement in an Organic Single Crystal.

Organic single crystals possess distinct advantages due to their highly ordered molecular structures, resulting in improved stability, enhanced carrier mobility, and superior optical characteristics. However, their mechanical rigidity and brittleness impede the applications in flexible and wearable optoelectronic devices. Here, photoluminescence (PL) emission from 2,6-diphenylanthracene (DPA) single crystals is studied under tensile strain, which shows PL enhancement by more than two times with a strain of ≈1.42%. Such a tension induced PL enhancement is reversible, exhibiting no clear optical degradations during 100 cycles of bending and recovery processes. Theoretical calculations reveal that the deformation of molecular structure under strain induces a decrease of the dihedral between anthracene and benzene moieties in DPA molecules. Further, the increased molecular conjugation enhances the molecular oscillator strength, leading to the brightened PL emission. Meanwhile, with the decreased dihedral, the molecular vibrations in DPA crystals are suppressed, which can reduce the non-radiative decay rate. In contrast, no tension induced PL enhancement is observed in polycrystalline DPA thin films as the strain can be released via the grain boundaries. This study highlights the superior optical performance of DPA single crystals under strain field, which will provide new possibilities for DPA-based flexible devices.

Synthesis and characterization of a highly fluorescent benzofuran dimer derived from estradiol

AbstractPd‐catalyzed cyclization of a fluorescent dimer in which two cores of the potent estrogenic estradiol are bridged by the 1,4‐diethynil benzene moiety led to a steroid dimer bearing the 1,4‐di(benzofuran‐2‐yl)benzene. The obtained compound showed an intense blue fluorescence characterized by a broad emission band between 350 and 550 nm, with four maxima at 384, 403, 435, and 456 nm. The benzofuran dimer showed an 18‐fold increased quantum yield compared with that of its synthetic precursor.

Synthesis, Characterization, in silico DFT, Molecular docking, ADMET Profiling Studies and Toxicity Predictions of Ag(I) Complex Derived from 4‐Aminoacetophenone

AbstractThe reaction of the synthesized (E)‐1‐(4‐((2,4‐dihydroxy‐6‐methylphenyl)diazenyl)phenyl)ethan‐1‐one, (DMPDE) ligand with Ag(I) ion at room temperature resulted in the formation of the complex; [Ag(DMPDE)(H2O)2]. 1H NMR, 13C NMR, FTIR, UV‐Vis, mass spectra, elemental analyses, thermal analysis (TGA/DTA), and molar conductance measurements were done to elucidate the structure of synthetic compounds. The results revealed an interesting geometrical variation; tetrahedral for Ag(I) complex. FT‐IR spectra demonstrated that the ligand (DMPDE) under investigation behaves as a bidentate ligand (N,O) through the nitrogen atom of the azo group which is the farthest of the acetophenone moiety and oxygen phenolic for benzene moiety and forms a stable five‐membered chelating ring. The electronic structure, molecular electrostatic potential (MEP) and quantum chemical calculations of the newly synthesized compounds are investigated theoretically at the DFT/B3LYP level of theory. Additionally, the ligand (DMPDE) and Ag(I) complex were screened against the growth of pathogenic bacteria [Actinomycosis (G+), E. Escherichia Coli (G−)] and fungi (Penicillium spp.) compared with the reference antibiotics, Chloramphenicol and Nystatin. Furthermore, 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) was used to evaluate the antioxidant activities of the ligand and its complex, which showed they both possess significant antioxidant properties in comparison with L‐ascorbic acid (Vit. C) as standard. Based on docking studies, (DMPDE) and Ag(I) complex demonstrated a greater affinity for (PDB ID: 3T88), which corresponds to Escherichia coli protein (−6.7818 kcal/mol) and (−6.7928 kcal/mol), respectively. Interestingly, the most active Ag(I) complex inside the active site of cervical cancer receptor (PDB ID: 4XR8) demonstrated a higher binding energy (−6.2631 kcal/mol) than free ligand (−5.8561 kcal/mol). In silico, ADMET displayed that compounds obey the Lipinski rule and the “Veber's rule. Consequently, is likely to exhibit oral bioavailability with good LD50 and a safety profile that includes non‐cytotoxicity, non‐immunotoxicity, and non‐skin sensitization. Finally, the compounds synthesized showed significant anticancer activity in human cervical cancer cell lines HeLa and SiHa compared with positive controls (cisplatin) and normal human hepatic cells (WRL‐68). In the present study, all tested cancer cell lines showed promising activity against Ag(I) complex, whose IC50 value ranged from (61.02 to 71.09) μg/mL.

Biological Evaluation of Isosteric Applicability of 1,3-Substituted Cuneanes as m-Substituted Benzenes Enabled by Selective Isomerization of 1,4-Substituted Cubanes.

We herein evaluate a biological applicability of 1,3-substituted cuneanes as an isostere of m-substituted benzenes based on its structural similarity. An investigation of a method to obtain 1,3-substituted cuneanes by selective isomerization of 1,4-substituted cubanes enables this attempt by giving a key synthetic step to obtain a cuneane analogs of pharmaceuticals having m-substituted benzene moiety. Biological evaluation of the synthesized analogs and in silico study of the obtained result revealed a potential usage of cuneane skeleton in medicinal chemistry.

The effect of weak π-π interactions on single-molecule electron transport properties of the tetraphenylethene molecule and its derivatives: a first-principles study.

Intramolecular π-π interactions are a significant research focus in fields such as chemistry, biology, and materials science. Different configurations of benzene-benzene moieties within a molecule can affect the magnitude of their π-π interactions, consequently influencing the electronic transport capabilities of the molecule. In this study, we designed three π-conjugated molecules, TPEM, TPEEM, and TEEPM, based on tetraphenylethene (TPE). These three molecules exhibit three distinct π-conjugated structures: linear cis-π-conjugation, linear trans-π-conjugation, and cross-π-conjugation. Thereinto, TPEM and TPEEM molecules share the same TPE core, with identical π-π interaction distances, while the TEEPM molecule has acetylene groups between the TPE units, thereby increasing the π-π interaction distances between the benzene moieties. Using density functional theory calculations combined with non-equilibrium Green's function (DFT+NEGF), our results reveal that the conductance order of different π-conjugated structures in TPEM and TPEEM molecules is as follows: cis > cross ≈ trans. Through analysis of transmission spectra, transmission pathways, and the innermost π orbitals, we find that in TPEM and TPEEM molecules, the cis- and cross-π-conjugated structures exhibit π-π interactions between benzene moieties and provide special through-space electron transport pathways, enhancing their electronic transport capabilities in coordination with the bonded molecular framework, whereas their trans-conjugated structures only allow electron transport along the molecular backbone. In contrast, in TEEPM molecule, due to the absence of π-π interactions, the conductance of different π-conjugated structures is primarily determined by the molecular backbone and follows the order: trans > cis > cross. These findings provide a theoretical basis for designing single-molecule electronic devices with multiple electron channels based on intramolecular π-π interactions.

A bipolar polymer cathode for sodium-ion batteries.

A bipolar polymer cathode material, containing redox-active azo benzene and diamine moieties, was synthesized for sodium-ion batteries. The n-type azo group and p-type amine group enable a wide cutoff window with an initial capacity of 93 mA h g-1 at 50 mA g-1 and a high voltage plateau at ∼3.3 V.

Triggered Crosslinking of Main-Chain Enediyne Polyurethanes via Bergman Cyclization.

Crosslinking chemistries occupy an important position in polymer modification with a particular importance when triggered in response to external stimuli. Enediyne (EDY) moieties are used as functional entities in this work, known to undergo a pericyclic Bergman cyclization (BC) to induce a triggered crosslinking of polyurethanes (PU) via the intermediately formed diradicals. Diamino-EDYs, where the distance between the enyne-moieties is known to be critical to induce a BC, are placed repetitively as main-chain structural elements in isophorone-based PUs to induce reinforcement upon heating, compression, or stretching. A 7-day compression under room temperature results in a ≈69% activation of the BC, together with the observation of an increase in tensile strength by 62% after 25 stretching cycles. The occurrence of BC is further proven by the decreased exothermic values in differential scanning calorimetry, together with characteristic peaks of the formed benzene moieties via IR spectroscopy. Purely heat-induced crosslinking contributes to 191% of the maximum tensile strength in comparison to the virgin PU. The BC herein forms an excellent crosslinking strategy, triggered by heat or force in PU materials.

Novel 1,2,4-Triazole- and Tetrazole-Containing 4H-Thiopyrano[2,3-b]quinolines: Synthesis Based on the Thio-Michael/aza-Morita–Baylis–Hillman Tandem Reaction and Investigation of Antiviral Activity

A novel method for synthesizing 1,2,4-triazole- and tetrazole-containing 4H-thiopyrano[2,3-b]quinolines using a new combination of the thio-Michael and aza-Morita–Baylis–Hillman reactions was developed. Target compounds were evaluated for their cytotoxicities and antiviral activities against influenza A/Puerto Rico/8/34 virus in MDCK cells. The compounds showed low toxicity and some exhibited moderate antiviral activity. Molecular docking identified the M2 channel and polymerase basic protein 2 as potential targets. We observed that the antiviral activity of thiopyrano[2,3-b]quinolines is notably affected by both the nature and position of the substituent within the tetrazole ring, as well as the substituent within the benzene moiety of quinoline. These findings contribute to the further search for new antiviral agents against influenza A viruses among derivatives of thiopyrano[2,3-b]quinoline.