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Mesogens, which are typically stiff rodlike or disklike molecules, are able to self-organize into liquid crystal (LC) phases in a certain temperature range. Such mesogens, or LC groups, can be attached to polymer chains in various configurations including within the backbone (main-chain LC polymers) or at the ends of side-chains attached to the backbone in an end-on or side-on configuration (side-chain LC polymers or SCLCPs), which can display synergistic properties arising from both their LC and polymeric character. At lower temperatures, chain conformations may be significantly altered due to the mesoscale LC ordering; thus, when heated from the LC ordered state through the LC to isotropic phase transition, the chains return from a more stretched to a more random coil conformation. This can cause macroscopic shape changes, which depend significantly on the type of LC attachment and other architectural properties of the polymer. Here, to study the structure–property relationships for SCLCPs with a range of different architectures, we develop a coarse-grained model that includes torsional potentials along with LC interactions of a Gay–Berne form. We create systems of different side-chain lengths, chain stiffnesses, and LC attachment types and track their structural properties as a function of temperature. Our modeled systems indeed form a variety of well-organized mesophase structures at low temperatures, and we predict higher LC-to-isotropic transition temperatures for the end-on side-chain systems than for analogous side-on side-chain systems. Understanding these phase transitions and their dependence on polymer architecture can be useful in designing materials with reversible and controllable deformations. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of two bis(dithiolene) proligands involving heteroatomic linkers such as 1,4-dithiine and dihydro-1,4-disiline between the two protected dithiolene moieties are described. Two bimetallic complexes involving these heteroatomic bridges between two redox active bis(cyclopentadienyl)molybdenum dithiolene moieties have been synthesized and characterized by electrochemistry, spectroelectrochemistry, and their properties rationalized with (TD-)DFT. Cyclic voltammetry experiments show sequential oxidation of the two redox centers with ΔE values between successive one-electron transfers varying according to the nature of the bridge. Depending on the nature of the heteroatomic bridge, the bis-oxidized complexes exhibit either a diradical character with both radicals essentially localized on the metallacycles, or a closed-shell dicationic state. [ABSTRACT FROM AUTHOR]

As the demand for clean water sources increases, it is crucial to identify the best wastewater treatment technology that is cost-effective and energy efficient. Despite their separation performance and durability limitations due to the membrane materials and chemicals used in current production techniques, membranes are useful for recovering water from contaminated water sources. This review focuses on nanocellulose-based membranes that utilize various methods, as biodegradable and inexpensive nanocellulose has been used widely in membrane research in recent years. The research regarding nanocellulose-based membranes is growing widely as incorporating nanocellulose enhances the hydrophilic properties and mechanical strength and increases the membrane adsorption capacities, which is ideal for future commercialization. The material high aspect ratio explains this potential, large specific surface area, good capacity retention, and environmental inertness. In addition to the benefits already described, active sites include chemical moieties that might improve the efficacy of pollutants attaching to surfaces. Besides that, nanocellulose could be chemically modified to increase the surface affinity and reactivity of membranes to remove specific contaminants efficiently. Future research directions for lignocellulosic nanocellulose for wastewater treatment and the difficulties and possibilities of nanocellulose-based membranes in these fields are also discussed. Lastly, the application of nanocelluloses in water treatment with an emphasis on membranes and filters fabricated primarily of nanocellulose. Hence, nanocellulose for these membrane applications provides tremendous potential for the wastewater treatment industry. [ABSTRACT FROM AUTHOR]

pH-responsive spirocyclic cyanine dyes were designed and synthesized. The equilibrium constant for cyclization (pKcycl) could be rationally controlled by changing the nucleophilic moiety and the side chains. Encapsulation in polymeric micelles inhibited the H-aggregation of the dye, and the pKcycl could be shifted according to the amphiphilic polymer employed. [ABSTRACT FROM AUTHOR]

Structurally symmetric dyes using functionalized fluorenes and benzotriazole as the main building moieties have been synthesized and found to exhibit efficient dual-state emission (DSE) and interesting two-wavelength or dual amplified spontaneous emission (dual-ASE) behaviors in the solution phase, which may benefit the development of organic gain materials with dual-wavelength amplification. [ABSTRACT FROM AUTHOR]

A synthetic method for preparation of optically active trifluoromethylthio (SCF3) compounds by a copper‐catalyzed regio‐ and enantioselective hydroboration of 1‐trifluoromethylthioalkenes with H‐Bpin has been developed. The enantioselective hydrocupration of an in situ generated CuH species and subsequent boration reaction generate a chiral SCF3‐containing alkylboronate, of which Bpin moiety can be further transformed to deliver various optically active SCF3 molecules. Computational studies suggest that the SCF3 group successfully controls the regioselectivity in the reaction. [ABSTRACT FROM AUTHOR]

A synthetic method for preparation of optically active trifluoromethylthio (SCF3) compounds by a copper‐catalyzed regio‐ and enantioselective hydroboration of 1‐trifluoromethylthioalkenes with H‐Bpin has been developed. The enantioselective hydrocupration of an in situ generated CuH species and subsequent boration reaction generate a chiral SCF3‐containing alkylboronate, of which Bpin moiety can be further transformed to deliver various optically active SCF3 molecules. Computational studies suggest that the SCF3 group successfully controls the regioselectivity in the reaction. [ABSTRACT FROM AUTHOR]

The field of supported catalysis has experienced increased attention with respect to the development of novel architectures for immobilizing catalytic species, aiming to maintain or enhance their activity while facilitating the easy recovery and reuse of the active moiety. Dendrimers have been identified as promising candidates capable of imparting such properties to catalysts through selective functionalization. The present study details the synthesis of two polyphosphorhydrazone (PPH) dendrons, each incorporating azide or acetylene groups at the core for subsequent coupling through "click" triazole chemistry. Employing this methodology, a novel PPH Janus dendrimer was successfully synthesized, featuring ten polyethylene glycol (PEG) chains on one side of the structure and ten Ru(p-cymene) derivatives on the other. This design was intended to confer dual properties, influencing solubility modulation, and allowing the presence of active catalytic moieties. The synthesized dendrimer underwent testing in the isomerization of allyl alcohols in organic solvents and biphasic solvent mixtures. The results demonstrated a positive dendritic effect compared with model monometallic and bimetallic species, providing a proof-ofconcept for the first PPH Janus dendrimer with tested applications in catalysis. [ABSTRACT FROM AUTHOR]

A novel cascade reaction initiated by an enantioselective aminocatalysed 1,3‐dipolar [6+4] cycloaddition between catalytically generated trienamines and 3‐oxidopyridinium betaines is presented. The [6+4] cycloadduct spontaneously undergoes an intramolecular enamine‐mediated aldol, hydrolysis, and E1cb sequence, which ultimately affords a chiral hexahydroazulene framework. In this process, three new C−C bonds and three new stereocenters are formed, enabled by a formal unfolding of the pyridine moiety from the dipolar reagent. The hexahydroazulenes are formed with excellent diastereo‐, regio‐ and periselectivity (>20 : 1), up to 96 % ee, and yields up to 52 %. Synthetic elaborations of this scaffold were performed, providing access to a variety of functionalised hydroazulene compounds, of which some were found to display biological activity in U‐2OS osteosarcoma cells in cell painting assays. [ABSTRACT FROM AUTHOR]

Wild‐type sortase A is an important virulence factor displaying a diverse array of proteins on the surface of bacteria. This protein display relies on the transpeptidase activity of sortase A, which is widely engineered to allow protein ligation and protein engineering based on the interaction between sortase A and peptides. Here an unknown interaction is found between sortase A from Staphylococcus aureus and nucleic acids, in which exogenously expressed engineered sortase A binds oligonucleotides in vitro and is independent of its canonical transpeptidase activity. When incubated with mammalian cells, engineered sortase A further mediates oligonucleotide labeling to the cell surface, where sortase A attaches itself and is part of the labeled moiety. The labeling reaction can also be mediated by many classes of wild‐type sortases as well. Cell surface GAG appears involved in sortase‐mediated oligonucleotide cell labeling, as demonstrated by CRISPR screening. This interaction property is utilized to develop a technique called CellID to facilitate sample multiplexing for scRNA‐seq and shows the potential of using sortases to label cells with diverse oligonucleotides. Together, the binding between sortase A and nucleic acids opens a new avenue to understanding the virulence of wild‐type sortases and exploring the application of sortases in biotechnology. [ABSTRACT FROM AUTHOR]

A novel fluorogenic alkyl diazirine photocrosslinker bearing an o‐hydroxycinnamate moiety has been developed for identification of the targets of bioactive molecules. The o‐hydroxycinnamate moiety can be converted to the corresponding 7‐hydroxycoumarin derivative, which should be created on the interacting site within the photocaptured target protein. The label yield and fluorescence intensity have been immensely improved in comparison with our previous aromatic crosslinkers to facilitate target identification in small quantities. [ABSTRACT FROM AUTHOR]

Endoplasmic reticulum (ER) is one of the most important sub‐cellular organelles which controls myriads of biological functions including protein biosynthesis with proper functional folded form, protein misfolding, protein transport into Golgi body for secretion, Ca2+ homeostasis and so on. Subsequently, dysregulation in ER function leads to ER stress followed by disease pathology like cancer. Hence, targeting ER in the cancer cells emerged as one of the futuristic strategies for cancer treatment. However, the major challenge is to selectively and specifically target ER in the sub‐cellular milieu in the cancer tissues, due to the lack of ER targeting chemical moieties to recognize the ER markers. To address this, in the last decade, numerous biomaterials were explored to selectively impair and image ER in cancer cells to induce ER stress. This review outlines those biomaterials which consists of carbon and silicon materials, lipid nanoparticles (liposomes and micelles), supramolecular self‐assembled nanostructures, cell membrane‐coated nanoparticles and metallic nanoparticles. Moreover, we also discuss the challenges and possible solutions of this promising field to usher the readers towards next‐generation ER targeted cancer therapy. [ABSTRACT FROM AUTHOR]

The coexistence of two fragments, a chiral isosteviol moiety and an achiral pyridinoyl-hydrazone moiety, in the molecules of pyridinoyl-hydrazone derivatives of isosteviol results in the realization of two distinct supramolecular motifs in their crystals, namely, a true homochiral motif and a pseudosymmetric homochiral motif. [ABSTRACT FROM AUTHOR]

Inkjet 3D printing has potential in the additive manufacturing of electronic circuits and devices. However, inks that can be used for printing layers with T5%>300 °C or hardness>200 MPa have been rarely reported. Cyanate ester (CE) polymers have excellent thermal stability, high strength, and low shrinkage compared to other common dielectric inks for inkjet 3D printing, but cannot be quickly shaped by ultraviolet (UV) irradiation or thermal treatment. Combining CEs with UV-curable monomers may be a possible way to accelerate crosslinking, but there are challenges from the adverse effects of the dilution of both monomers. In this study, dielectric inks with acrylate and cyanate moieties were developed. The low viscosity and surface tension of the CE precursor (Bisphenol E cyanate ester) were combined with photocurable acrylate diluent monomers and cross-linker to realize an ink suitable for inkjet 3D printing. An internal dual three-dimensional cross-linked network structure resin was prepared by a combination of photocuring and thermal curing with T5% up to 326.69 °C, hardness up to 431.84 MPa, dielectric constant of 2.70 at 8 GHz, and shrinkage of 1.64%. The developed dielectric inks can be applied to the 3D printing of printed circuit boards and other electronic devices that require dielectric properties. [ABSTRACT FROM AUTHOR]

A new series of hybrids of α-tocopherol and aryl/heterocyclic moieties through 1,2,3-triazole linker were made by rationally combining a biologically active α-tocopherol and substituted aromatic or heterocyclic moieties in single molecular frame using the click chemistry method. In a nutshell, the novel compounds (3a-h) were made by O-alkylating α-tocopherol, proceeded by copper (I)-catalyzed click reaction and the Huisgen [3 + 2] cycloaddition using various aromatic and heterocyclic azides (2a-h). By using 1H, 13C NMR, and mass spectroscopy techniques, all of the recently synthesized compounds were characterized and their antibacterial and antioxidant capabilities were assessed. Among the synthesized compounds, the most effective synthetic molecule against all bacterial strains was 3e with a naphthyl moiety, whereas 3d with a phenolic moiety showed potent antioxidant activity. To better understand the binding interactions, exploratory molecular docking investigation was conducted against the faBH enzyme of E. coli. [ABSTRACT FROM AUTHOR]

Herein, the chemical synthesis of new thiazole-based benzenesulfonamide-linked morpholine 4a,b–7via late-stage thiazolation of the corresponding thiosemicarbazone 3 is reported. The skeletal formulas of the new compounds were confirmed via instrumental analysis (FT-IR, NMR, and EI-MS). Their structural geometry optimization and the related quantum chemical descriptors were predicted via DFT-B3LYP/6-31G(d) calculations. Their antimicrobial screening demonstrated that all the tested compounds except 4a and b showed antibacterial efficacy against multidrug-resistant Klebsiella pneumoniae with an inhibition zone ranging from 10 to 15 mm. Compound 7, which bears a 4-thiazolone moiety, is the most potent towards K. pneumoniae with an inhibition zone diameter (IZD) of 15 mm and is the sole molecule that exhibited broad-spectrum antimicrobial activity against all pathogenic bacterial and fungal strains with an IZD spanning from 11 to 18 mm. Enzymatic in vitro bioassays indicated that 7 is more potent towards DHFR (IC50 = 0.521 ± 0.027 μg mL−1) than DNA gyrase (IC50 = 6.14 ± 0.27 μg mL−1). The best action mode via molecular docking disclosed that 7 is interlocked into the cavity centre of DHFR with a lower binding fitness (−123.615 kcal mol−1) than DNA gyrase (−112.537 kcal mol−1), validating the experimental results and showing that the 4-thiazolone-linked methyl ester and sulfonamide units are responsible for the hydrogen bonding interactions. Accordingly, thiazole 7 could be a promising antimicrobial lead candidate. [ABSTRACT FROM AUTHOR]

Starfish provide important saponins with diverse bioactivities as the secondary metabolites, among which 2‐O‐glycosylated glycosides are commonly found. Preparation of those 1,2‐trans 2‐O‐glycosylated glycosides usually relies on 2‐O‐acyl participation requiring the selective installation and cleavage of 2‐O‐acyl groups. A convergent synthesis using 2‐O‐glycosylated oligosaccharide donors would be more straightforward but also pose greater challenges. Herein, we report a convergent synthesis of a distinctive tetrasaccharide isolated from starfish Asterias rollestoni Bell. Dual 2‐(diphenylphosphinoyl)acetyl (DPPA) groups at O3 and O4 on galactose moiety led to high β‐selectivities (β/α=12/1 or β only) in the challenging [2+2] glycosylation, giving the desired tetrasaccharides in >90 % yields from the 2‐O‐glycosylated disaccharide donors. These synthetic studies have also unambiguously revised the structure of these natural tetrasaccharides. This work would facilitate further studies on new inhibitors of α‐glucosidase as hypoglycemic drugs. [ABSTRACT FROM AUTHOR]

We report the room temperature phosphorescence upon iodination on a crystalline eumelanin monomer with shielded hydroxyl moieties, ethyl 5,6‐dimethoxyindole‐2‐carboxylate (DMICE). Ultrafast intersystem crossing (ISC) is observed in the iodinated (IDMICE) as well as brominated (BDMICE) analogues of the eumelanin monomer derivative in solution. The triplet quantum yields (φT) and intersystem crossing rates (kISC) of the halogenated eumelanin derivatives are φTBDMICE ${{\phi{} }_{T}^{BDMICE}}$ =25.4±1.1 %; kISCBDMICE ${{k}_{ISC}^{BDMICE}}$ =1.95×109 s−1 and φTIDMICE ${{\phi{} }_{T}^{IDMICE}}$ =59.1±1.6 %; kISCIDMICE= ${{k}_{ISC}^{IDMICE}=}$ 1.36×1010 s−1, as monitored using transient absorption spectroscopy. Theoretical calculations based on nuclear ensemble method reveal that computed kISC and spin‐orbit coupling matrix elements for eumelanin derivatives are larger for IDMICE relative to BDMICE. The halogen and π‐π interactions, with distinct excitonic coupling and higher ISC rate promote phosphorescence in IDMICE molecular crystals. Accessing triplet excited states and resultant photoluminescence through structural modification of eumelanin scaffolds paves way for exploring the versatility of eumelanin‐inspired molecules as bio‐functional materials. [ABSTRACT FROM AUTHOR]

Incorporating stimuli‐responsive components into RNA constructs provides precise spatiotemporal control over RNA structures and functions. Despite considerable advancements, the utilization of redox‐responsive stimuli for the activation of caged RNAs remains scarce. In this context, we present a novel strategy that leverages post‐synthetic acylation coupled with redox‐responsive chemistry to exert control over RNA. To achieve this, we design and synthesize a series of acylating reagents specifically tailored for introducing disulfide‐containing acyl adducts into the 2′‐OH groups of RNA ("cloaking"). Our data reveal that these acyl moieties can be readily appended, effectively blocking RNA catalytic activity and folding. We also demonstrate the traceless release and reactivation of caged RNAs ("uncloaking") through reducing stimuli. By employing this strategy, RNA exhibits rapid cellular uptake, effective distribution and activation in the cytosol without lysosomal entrapment. We anticipate that our methodology will be accessible to laboratories engaged in RNA biology and holds promise as a versatile platform for RNA‐based applications. [ABSTRACT FROM AUTHOR]

One of the important issues for RNA-targeting drugs is to improve their binding properties. Herein, we modified berberine, which interacts with structured RNAs, with the guanidine moiety. Protein expression from target mRNA was efficiently reduced by the modification, suggesting a simple strategy to improve the therapeutic activity. [ABSTRACT FROM AUTHOR]

It is challenging to design and synthesize stable crystalline structures with heterogeneous pores. Herein, we design and synthesize a new azole ligand with rich aromatic moieties and trifluoromethyl groups, and construct a new stable metal azolate framework, which possesses a special three-dimensional (3D) framework with rare nonintersecting 1D/2D pore channels. [ABSTRACT FROM AUTHOR]

Incorporating stimuli‐responsive components into RNA constructs provides precise spatiotemporal control over RNA structures and functions. Despite considerable advancements, the utilization of redox‐responsive stimuli for the activation of caged RNAs remains scarce. In this context, we present a novel strategy that leverages post‐synthetic acylation coupled with redox‐responsive chemistry to exert control over RNA. To achieve this, we design and synthesize a series of acylating reagents specifically tailored for introducing disulfide‐containing acyl adducts into the 2′‐OH groups of RNA ("cloaking"). Our data reveal that these acyl moieties can be readily appended, effectively blocking RNA catalytic activity and folding. We also demonstrate the traceless release and reactivation of caged RNAs ("uncloaking") through reducing stimuli. By employing this strategy, RNA exhibits rapid cellular uptake, effective distribution and activation in the cytosol without lysosomal entrapment. We anticipate that our methodology will be accessible to laboratories engaged in RNA biology and holds promise as a versatile platform for RNA‐based applications. [ABSTRACT FROM AUTHOR]

Alkenyl oxindoles have been characterized as autophagosome-tethering compounds (ATTECs), which can target mutant huntingtin protein (mHTT) for lysosomal degradation. In order to expand the application of alkenyl oxindoles for targeted protein degradation, we designed and synthesized a series of heterobifunctional compounds by conjugating different alkenyl oxindoles with bromodomain-containing protein 4 (BRD4) inhibitor JQ1. Through structure-activity relationship study, we successfully developed JQ1-alkenyl oxindole conjugates that potently degrade BRD4. Unexpectedly, we found that these molecules degrade BRD4 through the ubiquitin-proteasome system, rather than the autophagy-lysosomal pathway. Using pooled CRISPR interference (CRISPRi) screening, we revealed that JQ1-alkenyl oxindole conjugates recruit the E3 ubiquitin ligase complex CRL4DCAF11 for substrate degradation. Furthermore, we validated the most potent heterobifunctional molecule HL435 as a promising drug-like lead compound to exert antitumor activity both in vitro and in a mouse xenograft tumor model. Our research provides new employable proteolysis targeting chimera (PROTAC) moieties for targeted protein degradation, providing new possibilities for drug discovery. Targeted protein degradation strategies are promising avenues for drug development, but it is important to broaden the toolbox of E3 ligases that can be engaged. This study shows that alkenyl oxindole compounds act as novel E3 ligase ligands and recruit the CRL4-DCAF11 E3 ubiquitin ligase complex for substrate degradation. [ABSTRACT FROM AUTHOR]

Herein, we demonstrate that carbamoyl radicals generated through an organophotocatalytic protocol from 4‐carbamoyl‐dihydropyridines (carbamoyl‐DHPs) can be incorporated into Morita‐Baylis‐Hillman (MBH) carbonates, affording a range of polyfunctionalized scaffolds with yields ranging from 63–98%. Reaction monitoring experiments, scale‐up, reuse of the organophotocatalyst, and the hydrogenation of the succinamic ester's alkene moiety was also conducted, in order to showcase the mechanistic features and the robustness of this photochemical protocol. [ABSTRACT FROM AUTHOR]

We described a base‐promoted O‐arylation of N3‐hydroxyl quinazolinones with diaryliodonium salts and sequential BF3 ⋅ OEt2 and visible light‐controlled [3,3]‐ or [1,3]‐rearrangements of quinazolinone N−O aryl moieties to prepare a variety of 2‐(quinazolin‐4‐yloxy)phenols and atropisomeric 3‐(2‐hydroxyphenyl)quinazolin‐4‐ones in 44%‐75% yields and 28%‐70% yields, respectively. Mechanistic studies showed that HBF4 generated in situ from BF3 ⋅ Et2O and water served as the catalyst in this process and aryloxyquinazolinium salts are vital intermediates promoting the [3,3]‐ or [1,3]‐rearrangements. The N−O aryl moieties of aryloxyquinazolinium salts were found to undergo solely [3,3]‐rearrangement with heating whereas [1,3]‐rearrangement occurred via a radical process under irradiation of visible light. This method highlights the formation of aryloxyquinazolinium salts based on the use of BF3 ⋅ OEt2 and visible light to prompt [1,3]‐rearrangement generating atropisomeric quinazolinones. [ABSTRACT FROM AUTHOR]

The eukaryotic mRNA life cycle includes transcription, nuclear mRNA export and degradation. To quantify all these processes simultaneously, we perform thiol-linked alkylation after metabolic labeling of RNA with 4-thiouridine (4sU), followed by sequencing of RNA (SLAM-seq) in the nuclear and cytosolic compartments of human cancer cells. We develop a model that reliably quantifies mRNA-specific synthesis, nuclear export, and nuclear and cytosolic degradation rates on a genome-wide scale. We find that nuclear degradation of polyadenylated mRNA is negligible and nuclear mRNA export is slow, while cytosolic mRNA degradation is comparatively fast. Consequently, an mRNA molecule generally spends most of its life in the nucleus. We also observe large differences in the nuclear export rates of different 3'UTR transcript isoforms. Furthermore, we identify genes whose expression is abruptly induced upon metabolic labeling. These transcripts are exported substantially faster than average mRNAs, suggesting the existence of alternative export pathways. Our results highlight nuclear mRNA export as a limiting factor in mRNA metabolism and gene regulation. Author summary: In our work, we aim to quantify two fundamental processes in the life cycle of a eukaryotic messenger RNA (mRNA), namely export from the nuclear compartment to the cytosol, and degradation. To enable a genome-wide evaluation, we have implemented an experimental-bioinformatics approach. We use a chemical moiety, 4-thiouridine (4sU), which is incorporated into RNA molecules when added to the solution, to mark RNA which is recently synthesized and distinguish it from already existing RNA. We take a time series of recent and already existing RNA within both the nuclear and cytoplasmic cellular compartments. We have devised a computational model that can reliably quantify mRNA nuclear export and cytosolic degradation rates from this data. We revealed that the export of mRNA from the nucleus to the cytoplasm emerges as a comparatively tardy event. Subsequently, mRNA molecules within the cytoplasm experience swift degradation. This identifies the nucleus as the predominant residence for the greater portion of an mRNA's lifecycle. Yet, we have also found notable exceptions from this scheme which are immediately exported after transcription without delay, suggesting the plausible existence of alternative mRNA export pathways. In sum, our research underscores the pivotal role of nuclear mRNA export as a determining factor in the orchestration of mRNA metabolism and the regulation of gene expression within eukaryotic cells. [ABSTRACT FROM AUTHOR]

Stimulus-responsive materials containing selenide under oxidizing conditions have wide application prospects, especially in biomedicine. Due to the intricate preparation process, the scarcity of studies on the structure–activity relationship of regulatory factors in the oxidative stimulus response poses challenges to material design. Herein, based on selenol-ene chemistry, a diverse library of unsymmetric selenides is synthesized, enabling systematic investigation into the regulation of selenide oxidative elimination with variable substituent groups and positions. The α/β-positions of β-carbonyl unsymmetric selenides are efficiently modified with electron-donating or electron-withdrawing groups through a one-pot, two-step reaction involving ammonolysis of γ-selenobutyrolactone (SBL), followed by nucleophilic addition with unsaturated acrylate. In situ NMR tracking shows that the oxidative elimination of selenide had a distinct substituent effect. Both the electron and steric effects of the substituent influence the induction period of the selenide oxidative and elimination reactions. With the optimal substituent and position, the selenides would exhibit a timebomb-type response upon oxidation stimulus. Finally, a novel amphiphilic polymer comprising selenide-linked polyethylene glycol (PEG) and cholesterol moieties is synthesized as a representative ROS-sensitive material and exhibits a time-dependent reduction in micelle size. [ABSTRACT FROM AUTHOR]

The current study includes synthetic approaches for some linear heterocyclic compounds containing chromone moiety. Chromenopyridopyrimidine bearing amino-thione functions 4 was efficiently synthesized starting from 6,8-dimethylchromone-3-carbonitrile (1). The novel chromenopyridothiadiazolopyrimidines were synthesized through condensation of the key precursor 4 with some mono-electrophilic reagents. In addition, heteroannulated chromenopyridopyrimidothiadiazines were synthesized through condensation of compound 4 with some α-halogenated carbonyl reagents. The synthesized products were examined for their antimicrobial efficiency appearing remarkable activity against the inspected microorganisms especially compounds 7, 12 and 14. The synthesized products were inferred using analytical and spectral data. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: A new family of dibenzoullazine derivatives was synthesized through 1,3‐dipolar cycloaddition of polycyclic aromatic azomethine ylides with alkynylbenziodoxoles followed by oxidation. The benziodoxole moiety in the resulting products was used as a versatile linchpin for the synthesis of structurally diverse functional dibenzoullazines that are difficult to access by other synthetic methods. [ABSTRACT FROM AUTHOR]

The present study employs X-ray photoelectron spectroscopy (XPS) to analyze plastic samples subjected to degradation processes with the aim to gain insight on the relevant chemical processes and disclose fragmentation mechanisms. Two model plastics, namely polystyrene (PS) and polyethylene (PE), are selected and analyzed before and after artificial UV radiation-triggered weathering, under simulated environmental hydrodynamic conditions, in fresh and marine water for different time intervals. The object of the study is to identify and quantify chemical groups possibly evidencing the occurrence of hydrolysis and oxidation reactions, which are the basis of degradation processes in the environment, determining macroplastic fragmentation. Artificially weathered plastic samples are analyzed also by Raman and FT-IR spectroscopy. Changes in surface chemistry with weathering are revealed by XPS, involving the increase in chemical moieties (hydroxyl, carbonyl, and carboxyl functionalities) which can be correlated with the degradation processes responsible for macroplastic fragmentation. On the other hand, the absence of significant modifications upon plastics weathering evidenced by Raman and FT-IR spectroscopy confirms the importance of investigating plastics surface, which represents the very first part of the materials exposed to degradation agents, thus revealing the power of XPS studies for this purpose. The XPS data on experimentally weathered particles are compared with ones obtained on microplastics collected from real marine environment for investigating the occurring degradation processes. [ABSTRACT FROM AUTHOR]

We present a systematic review of the methods developed for the synthesis of the aromathecin family of compounds (benz[6,7]indolizino[1,2-b]quinolin-11(13H)-ones) and their derivatives. These methods can be broadly classified into four categories based on the construction of pentacyclic structures: Category 1: by constructing a pyridone moiety (D-ring) on the pyrroloquinoline ring (A/B/C-ring), Category 2: by constructing a pyridine moiety (B-ring) on the pyrroloisoquinolone ring (C/D/E-ring), Category 3: by constructing an indolizidinone moiety (C/D-ring) in a tandem reaction, and Category 4: by constructing a pyrrolidine moiety (C-ring) on the isoquinolone ring (D/E-ring). [ABSTRACT FROM AUTHOR]

A novel chiral photoswitch composed of a binaphthyl unit and a hexafluorocyclopentene ring has been synthesized. This chiral photoswitch exhibited thermally reversible photochromism between the binaphthyl and helicenoid forms based on 6π-electrocyclization. The helicity of the binaphthyl moiety was reversed upon stereospecific photocyclization and reverted back during the thermal ring opening. [ABSTRACT FROM AUTHOR]

The highly strained, phenylene‐derived organic cages are typically regarded as very rigid entities, yet their deformation potential and supramolecular properties remain underexplored. Herein, we report a pliable conjugated phenylene nanocage by synergistically merging rigid and flexible building blocks. The anisotropic cage molecule contains branched phenylene chains capped by a calix[6]arene moiety, the delicate conformational changes of which endow the cage with a remarkably deformable cavity. When complexing with fullerene guests, the cage showcases excellent guest‐adaptivity, with its cavity volume capable of swelling by as much as 85 %. [ABSTRACT FROM AUTHOR]

Mechanically interlocked molecules (MIMs) represent an exciting yet underexplored area of research in the context of carbon nanoscience. Recently, work from our group and others has shown that small carbon nanotube fragments—[n]cycloparaphenylenes ([n]CPPs) and related nanohoop macrocycles—may be integrated into mechanically interlocked architectures by leveraging supramolecular interactions, covalent tethers, or metal‐ion templates. Still, available synthetic methods are typically difficult and low yielding, and general methods that allow for the creation of a wide variety of these structures are limited. Here we report an efficient route to interlocked nanohoop structures via the active template Cu‐catalyzed azide‐alkyne cycloaddition (AT−CuAAC) reaction. With the appropriate choice of substituents, a macrocyclic precursor to 2,2′‐bipyridyl embedded [9]CPP (bipy[9]CPP) participates in the AT−CuAAC reaction to provide [2]rotaxanes in near‐quantitative yield, which can then be converted into the fully π‐conjugated catenane structures. Through this approach, two nanohoop[2]catenanes are synthesized which consist of a bipy[9]CPP catenated with either Tz[10]CPP or Tz[12]CPP (where Tz denotes a 1,2,3‐triazole moiety replacing one phenylene ring in the [n]CPP backbone). [ABSTRACT FROM AUTHOR]

The highly strained, phenylene‐derived organic cages are typically regarded as very rigid entities, yet their deformation potential and supramolecular properties remain underexplored. Herein, we report a pliable conjugated phenylene nanocage by synergistically merging rigid and flexible building blocks. The anisotropic cage molecule contains branched phenylene chains capped by a calix[6]arene moiety, the delicate conformational changes of which endow the cage with a remarkably deformable cavity. When complexing with fullerene guests, the cage showcases excellent guest‐adaptivity, with its cavity volume capable of swelling by as much as 85 %. [ABSTRACT FROM AUTHOR]

Mechanically interlocked molecules (MIMs) represent an exciting yet underexplored area of research in the context of carbon nanoscience. Recently, work from our group and others has shown that small carbon nanotube fragments—[n]cycloparaphenylenes ([n]CPPs) and related nanohoop macrocycles—may be integrated into mechanically interlocked architectures by leveraging supramolecular interactions, covalent tethers, or metal‐ion templates. Still, available synthetic methods are typically difficult and low yielding, and general methods that allow for the creation of a wide variety of these structures are limited. Here we report an efficient route to interlocked nanohoop structures via the active template Cu‐catalyzed azide‐alkyne cycloaddition (AT−CuAAC) reaction. With the appropriate choice of substituents, a macrocyclic precursor to 2,2′‐bipyridyl embedded [9]CPP (bipy[9]CPP) participates in the AT−CuAAC reaction to provide [2]rotaxanes in near‐quantitative yield, which can then be converted into the fully π‐conjugated catenane structures. Through this approach, two nanohoop[2]catenanes are synthesized which consist of a bipy[9]CPP catenated with either Tz[10]CPP or Tz[12]CPP (where Tz denotes a 1,2,3‐triazole moiety replacing one phenylene ring in the [n]CPP backbone). [ABSTRACT FROM AUTHOR]

A porous organic polymer (POP) has been developed for dual-ion storage in all organic symmetric rechargeable batteries. The triphenylamine-pyrene-based POP could host sodium and hexafluorophosphate ions acting as the anode and the cathode, respectively, through the adsorption-intercalation and insertion mechanism. The current study highlights the concept of widening the potential window of a dual ion battery by judicious selection of the constituent moieties. [ABSTRACT FROM AUTHOR]

Stretching a segment of a polymer beyond its contour length makes its (primarily backbone) bonds more dissociatively labile, which enables polymer mechanochemistry. Integrating some backbone bonds into suitably designed molecular moieties yields mechanistically and kinetically diverse chemistry, which is becoming increasingly exploitable. Examples include, most prominently, attempts to improve mechanical properties of bulk polymers, as well as prospective applications in drug delivery and synthesis. This review aims to highlight an emerging effort to apply the concepts and experimental tools of mechanochemistry to fundamental physical questions in soft matter. A succinct summary of the state‐of‐the‐knowledge of the field, with emphasis on foundational concepts and generalizable observations, is followed by analysis of 3 recent examples of mechanochemistry yielding molecular‐level details of elastomer failure, macromolecular chain dynamics in elongational flows and kinetic allostery. We conclude with reasons to assume that the highlighted approaches are generalizable to a broader range of physical problems than considered to date. [ABSTRACT FROM AUTHOR]

Selective partial C--Cl bond reduction represents an important strategy for the construction of valuable chlorine-containing skeletons. Herein, we report an efficient and straightforward mono-(deutero)hydrodechlorination strategy of various trichloroacetyl esters and amides for the incorporation of gem-dichloromethyl moieties. The proposed mechanism involves key electron donor--acceptor (EDA) complexes formed between catalytic cyclohexanethiol (CySH) and substrates, which undergo single-electron transfer (SET) processes under blue light irradiation to provide the gem-dichloro radical anion and CyS•. A gram-scale reaction and late-stage modification of bioactive molecules further demonstrate the potential utility of this methodology. [ABSTRACT FROM AUTHOR]

Retrosynthetic design and synthesis with structural isolation of two unprecedented core modified N-confused N-fused porphodimethene-like porphyrinoids possessing a [5.5.5.5] tetracyclic ring with tunable photophysical properties is reported. The solid-state X-ray crystal structure reveals the expected cis geometry for the meso-sp³ carbons. Controlled chemical oxidation of the porphodimethene analogue 11 bearing the N-confused pyrrole moiety to the corresponding porphotrimethene 12 has been achieved in quantitative yield, while 10 bearing the N-methyl N-confused pyrrole moiety remained unsusceptible to chemical oxidation. All three S2N3 hybrid N-confused N-fused porphodi(tri)methene-like porphyrinoids 10-12 could recognize the fluoride anion with high selectivity; however, porphodimethene 10 and porphotrimethene 12 do so via deprotonation rather than an anion recognition based mechanism as has been anticipated in the case of porphodimethene 11. [ABSTRACT FROM AUTHOR]

Stretching a segment of a polymer beyond its contour length makes its (primarily backbone) bonds more dissociatively labile, which enables polymer mechanochemistry. Integrating some backbone bonds into suitably designed molecular moieties yields mechanistically and kinetically diverse chemistry, which is becoming increasingly exploitable. Examples include, most prominently, attempts to improve mechanical properties of bulk polymers, as well as prospective applications in drug delivery and synthesis. This review aims to highlight an emerging effort to apply the concepts and experimental tools of mechanochemistry to fundamental physical questions in soft matter. A succinct summary of the state‐of‐the‐knowledge of the field, with emphasis on foundational concepts and generalizable observations, is followed by analysis of 3 recent examples of mechanochemistry yielding molecular‐level details of elastomer failure, macromolecular chain dynamics in elongational flows and kinetic allostery. We conclude with reasons to assume that the highlighted approaches are generalizable to a broader range of physical problems than considered to date. [ABSTRACT FROM AUTHOR]

BODIPY based molecules functionalized with water soluble moieties have been developed and recognized as liable triplet photosensitizers for phototherapeutic applications. In this work, we have prepared BODIPY analogues with dicarboxylic acid groups and bearing iodine or fullerene moieties for efficient intersystem crossing which display far‐red absorption band and high singlet oxygen production both in organic and aqueous media. In this perspective by using similar design the effect of the halogenation of the dyes versus spin converter on the skeleton were compared. The structures of the synthesized BODIPYs and BODIPY‐C60 (6–10) were elucidated by mass, 1H and 13C NMR spectroscopic techniques. Photophysical and photochemical properties of the compounds were examined using UV‐Vis. absorption and fluorescence emission spectrophotometers. The absorption intensities of the trap molecules (DPBF and ADBA) reduced because of singlet oxygen generation in the media. This study may provide useful infrastructure to elucidate the relationship between the use of fullerene (9) or iodine (10) where singlet oxygen quantum yield of 9 and 10 are determined as 0.87 and 0.97 respectively. [ABSTRACT FROM AUTHOR]

The amide bond is one of the most important structural units in nature, as it is part of the backbone of peptides and natural proteins, as well as some essential amino acids, DNA, RNA, hormones, or vitamins found in the body. Furthermore, this bond is significant in the pharmaceutical industry due to its presence in the structure of numerous APIs contained in drugs. This paper reviews the most important methods collected in the bibliography for the preparation of this moiety. [ABSTRACT FROM AUTHOR]

Pi (π) interactions originating from the N-H bond of amine and ethylene moiety have been explored on the mechanism of aromatic nucleophilic substitution (ArSN) of the nitro group of 4-methylene-5,7-dinitroquinazoline with methylamine in the gas phase and solvent media within DFT framework. The free energy profiles confirmed that the amination should take place at peri-position and calculations support the one-step mechanism through a transition state with no intermediate in the reaction route. Stabilisation of peri-transition state by intramolecular weak interaction akin to hydrogen bonding N-H—CH2 = C leads to the regioselective amination at peri-position of 4-methylene-5,7-dinitroquinazoline. The intramolecular hydrogen bond interactions at N-H—CH2 = C in the peri-transition state are strongly supported by a red shift in N-H stretching vibrations in simulated IR spectra and are confirmed by studying energetics of amination of structural/electronic analogues of 4-methylene-5,7-dinitroquinazoline. The present study established that ethylene plays an important role as an efficient H-bond acceptor in fixing the regioselectivity at peri-position in the amination of 4-methylene-5,7-dinitroquinazoline. This is the first-ever report for the exploration of the role of ethylene moiety as a hydrogen bond acceptor in mediating the regioselectivity of organic reactions. [ABSTRACT FROM AUTHOR]

A series of 4-carboxyphenyl/4-hydroxyphenyl meso-substituted porphyrins were synthesized, purified, and characterized. The compounds exhibited anti-HIV-1 activities, in vitro, under both non-photodynamic (non-PDT) and photodynamic (PDT) conditions. Specifically, the porphyrins inhibited HIV-1 virus entry, with c-PB2(OH)2 and PB(OH)3 showing significant anti-HIV-1 activity. All of the porphyrins inhibited HIV-1 subtype B and C virus entry under PDT conditions. Our study demonstrated that the compounds bearing combinations of 4-carboxyphenyl/4-hydroxyphenyl moieties were not toxic even at higher concentrations, as compared to the reference porphyrins 5,10,15,20-tetra-(4-carboxyphenyl)porphyrin (TCPP) and 5,10,15,20-tetra-(4-hydroxyphenyl)porphyrin (THPP), under PDT conditions. This study underscores the promising potential of these compounds as HIV entry inhibitors in both non-PDT and PDT scenarios. [ABSTRACT FROM AUTHOR]

Dye-decolorizing peroxidases are heme peroxidases with a broad range of substrate specificity. Their physiological function is still largely unknown, but a role in the depolymerization of plant cell wall polymers has been widely proposed. Here, a new expression system for bacterial dye-decolorizing peroxidases as well as the activity with previously unexplored plant molecules are reported. The dye-decolorizing peroxidase from Amycolatopsis 75iv2 (DyP2) was heterologously produced in the Gram-positive bacterium Streptomyces lividans TK24 in both intracellular and extracellular forms without external heme supplementation. The enzyme was tested on a series of O-glycosides, which are plant secondary metabolites with a phenyl glycosidic linkage. O-glycosides are of great interest, both for studying the compounds themselves and as potential models for studying specific lignin-carbohydrate complexes. The primary DyP reaction products of salicin, arbutin, fraxin, naringin, rutin, and gossypin were oxidatively coupled oligomers. A cleavage of the glycone moiety upon radical polymerization was observed when using arbutin, fraxin, rutin, and gossypin as substrates. The amount of released glucose from arbutin and fraxin reached 23% and 3% of the total substrate, respectively. The proposed mechanism suggests a destabilization of the ether linkage due to the localization of the radical in the para position. In addition, DyP2 was tested on complex lignocellulosic materials such as wheat straw, spruce, willow, and puri fied water-soluble lignin fractions, but no remarkable changes in the carbohydrate pro file were observed, despite obvious oxidative activity. The exact action of DyP2 on such lignin-carbohydrate complexes therefore remains elusive. [ABSTRACT FROM AUTHOR]

meso-Tetrahexylporphyrin was converted to its corresponding 7,8-dihydroxychlorin using an osmium tetroxide-mediated dihydroxylation strategy. Its diol moiety was shown to be able to undergo a number of subsequent oxidation reactions to form a chlorin dione and porpholactone, the first meso-alkylporphyrin-based porphyrinoid containing a non-pyrrolic building block. Further, the diol chlorin was shown to be susceptible to dehydration, forming the porphyrin enol that is in equilibrium with its keto-chlorin form. The meso-hexylchlorin dione could be reduced and it underwent mono- and bis-methylation reactions using methyl-Grignard reagents, and trifluoromethylation using the Ruppert-Prakash reagent. The optical and spectroscopic properties of the products are discussed and contrasted to their corresponding meso-aryl derivatives (where known). This contribution establishes meso-tetrahexyl-7,8-dihydroxychlorins as a new and versatile class of chlorins that is susceptible to a broad range of conversions to generate functionalized chlorins and a pyrrole-modified chlorin analogue. [ABSTRACT FROM AUTHOR]

The two star-shaped viologens containing 1,3,5-substituted phenyl (1) and triphenylamine (2) central cores and n-hexyl chains were synthesized and characterized. Both compounds exhibited promising optoelectronic properties and underwent multiple oxidation/reduction processes resulting in various colors. Four possible redox states of tripyridium salt containing a phenyl or triphenylamine core can occur depending on the applied potentials. The wide color range, from colorless through blue, azure to green-gray, was observed during the electrochemical reduction of compound 1. In the case of compound 2, the color change observed during spectroelectrochemical measurements was from yellow to colorless during the cathodic process and from yellow to green during the anodic process. The observed color change for both viologens was reversible. The triphenylamine-cored viologen (2) also exhibited emission in visible range and solvatochromism. It also exhibited luminescence in the solid state when excited with a UV lamp. These studies provide insights into the design of advanced materials for applications in displays. [ABSTRACT FROM AUTHOR]

The Rutaceae family is one of the most studied plant families due to the large number of alkaloids isolated from them with outstanding biological properties, among them the quinoline-based alkaloids Graveoline 1 and Dubamine 2. The most common methods for the synthesis of alkaloids 1 and 2 and their derivatives involves cycloaddition reactions or metal-catalyzed coupling processes but with some limitations in scope and functionalization of the quinoline moiety. As a continuation of our current studies on the synthesis and chemical transformation of 2-aminochalcones, we are reporting here an efficient metal-free approach for the total synthesis of alkaloids 1 and 2 along with their analogues with structural diversity, through a two-step sequence involving intramolecular cyclization, oxidation/aromatization, N-methylation and oxidative C-C bond processes, starting from dihydroquinolin-4-ones as common precursors for the construction of the structures of both classes of alkaloids. [ABSTRACT FROM AUTHOR]