Binuclear Cluster Research Articles

Identifying substrate triggers for appressorium development in Setosphaeria turcica and functional characterization of Zn(II)2Cys6 transcription factors StTF1 and StTF2

Northern corn leaf blight is a devastating disease caused by Setosphaeria turcica (S. turcica), leading to significant yield losses in maize. S. turcica initiates infection through a specialized structure known as the appressorium, which only forms on conducive substrates. In this study, we introduce a semi‑silicone water polyurethane resin (Si-PUD) that induces only germ tube formation from S. turcica conidia. A mixed coating of Si-PUD and polytetrafluoroethylene successfully triggers appressorium formation. Both coatings maintain optical transparency, chemical resistance, and thermal stability, which facilitate microscopic observations and the development of high-throughput systems. These coatings also demonstrate similar effects on Bipolaris maydis (B. maydis), suggesting their potential universal applicability. Utilizing coating-induced synchronous appressorium formation and proteomic analyses, we identified five genes essential for S. turcica appressorium development. Functional analyses of two zinc binuclear cluster domain-containing transcription factors, StTF1 and StTF2, revealed their critical roles in appressorium development and pathogenicity. This study not only develops a novel method for inducing appressorium formation but also lays the groundwork for rapid screening of environmentally-friendly fungicides that inhibit appressorium development.

A luminescent Cu2I2P2S2-type binuclear complex and its fluorescence sensing for pyridine.

Luminescent CuI complexes are an important class of coordination compounds due to their relative abundance, low cost and ability to display excellent luminescence. The title Cu2I2P2S2-type binuclear complex, di-μ-iodido-bis[(thiourea-κS)(triphenylphosphine-κP)copper(I)], [Cu2I2(CH4N2S)2(C18H15P)2], conventionally abbreviated as Cu2I2TPP2TU2, where TPP and TU represent triphenylphosphine and thiourea, respectively, is described. In this complex, each CuI atom adopts a CuI2PS four-coordination mode and pairs of atoms are connected to each other by two μ2-I ligands to form a centrosymmetric binuclear cluster. It was also found that the paper-based film of this complex exhibited obvious luminescence light-up sensing for pyridine and 4-methylpyridine.

Two new 3D cobalt(II) coordination polymers constructed by semi-rigid carboxylic acid ligand: Syntheses, structures and properties

Two novel coordination polymers, {[Co2(L)(H2O)5]·H2O}n (1), and {[Co5(L)2(H2O)6(μ3-OH)2]·2C3H7NO·2H2O}n (2) (H4L = 3, 3′, 5, 5′-diphenyl ether tetracarboxylic acid, C16H10O9) have been synthesized by assembling semi-rigid aromatic polycarboxylic acids with transition-metal cobalt salts, and structurally characterized by elemental analysis, thermogravimetric analysis, IR spectrum, powder X-ray diffraction, and single crystal X-ray diffraction analysis. Structural analysis showed both the L ligands in CP 1 and CP 2 were regarded as 4 connection points, while the binuclear clusters in CP 1 and the pentanuclear clusters in CP 2 were regarded as 4 connection points and 8 connection points, respectively. Finally, both CP 1 and CP 2 were 3D network structures connected by two nodes (4, 4-connected for CP 1 and 4, 8-connected for CP 2). In addition, temperature-dependent susceptibilities have been measured in the range of 2 to 300 K, indicating that both CP 1 and CP 2 have antiferromagnetic coupling between adjacent Co(II) ions. Finally, Electrochemical experiments show that the CP 1 and CP 2 have good electrochemical behaviors.

Discovery of a Ni2+-dependent heterohexameric metformin hydrolase

The biguanide drug metformin is a first-line blood glucose-lowering medication for type 2 diabetes, leading to its presence in the global environment. However, little is known about the fate of metformin by microbial catabolism. Here, we characterize a Ni2+-dependent heterohexameric enzyme (MetCaCb) from the ureohydrolase superfamily, catalyzing the hydrolysis of metformin into guanylurea and dimethylamine. Either subunit alone is catalytically inactive, but together they work as an active enzyme highly specific for metformin. The crystal structure of the MetCaCb complex shows the coordination of the binuclear metal cluster only in MetCa, with MetCb as a protein binder of its active cognate. An in-silico search and functional assay discover a group of MetCaCb-like protein pairs exhibiting metformin hydrolase activity in the environment. Our findings not only establish the genetic and biochemical foundation for metformin catabolism but also provide additional insights into the adaption of the ancient enzymes toward newly occurred substrate.

A dual RNA-seq analyses revealed dynamic arms race during the invasion of walnut by Colletotrichum gloeosporioides

BackgroundWalnut anthracnose caused by Colletotrichum gloeosporioides seriously endangers the yield and quality of walnut, and has now become a catastrophic disease in the walnut industry. Therefore, understanding both pathogen invasion mechanisms and host response processes is crucial to defense against C. gloeosporioides infection.ResultsHere, we investigated the mechanisms of interaction between walnut fruits (anthracnose-resistant F26 fruit bracts and anthracnose-susceptible F423 fruit bracts) and C. gloeosporioides at three infection time points (24hpi, 48hpi, and 72hpi) using a high-resolution time series dual transcriptomic analysis, characterizing the arms race between walnut and C. gloeosporioides. A total of 20,780 and 6670 differentially expressed genes (DEGs) were identified in walnut and C. gloeosporioides against 24hpi, respectively. Generous DEGs in walnut exhibited opposite expression patterns between F26 and F423, which indicated that different resistant materials exhibited different transcriptional responses to C. gloeosporioides during the infection process. KEGG functional enrichment analysis indicated that F26 displayed a broader response to C. gloeosporioides than F423. Meanwhile, the functional analysis of the C. gloeosporioides transcriptome was conducted and found that PHI, SignalP, CAZy, TCDB genes, the Fungal Zn (2)-Cys (6) binuclear cluster domain (PF00172.19) and the Cytochrome P450 (PF00067.23) were largely prominent in F26 fruit. These results suggested that C. gloeosporioides secreted some type of effector proteins in walnut fruit and appeared a different behavior based on the developmental stage of the walnut.ConclusionsOur present results shed light on the arms race process by which C. gloeosporioides attacked host and walnut against pathogen infection, laying the foundation for the green prevention of walnut anthracnose.

Computational therapeutic repurposing of tavaborole targeting arginase-1 for venous leg ulcer

Venous leg ulcers (VLUs) pose a growing healthcare challenge due to aging, obesity, and sedentary lifestyles. Despite various treatments available, addressing the complex nature of VLUs remains difficult. In this context, this study investigates repurposing boronated drugs to inhibit arginase 1 activity for VLU treatment. The molecular docking study conducted by Schrodinger GLIDE targeted the binuclear manganese cluster of arginase 1 enzyme (2PHO). Further, the ligand-protein complex was subjected to molecular dynamic studies at 500 ns in Gromacs-2019.4. Trajectory analysis was performed using the GROMACS simulation package of protein RMSD, RMSF, RG, SASA, and H-Bond. The docking study revealed intriguing results where the tavaborole showed a better docking score (-3.957 Kcal/mol) compared to the substrate L-arginine (-3.379 Kcal/mol) and standard L-norvaline (-3.141 Kcal/mol). Tavaborole interaction with aspartic acid ultimately suggests that the drug molecule binds to the catalytic site of arginase 1, potentially influencing the enzyme's function. The dynamics study revealed the compounds' stability and compactness of the protein throughout the simulation. The RMSD, RMSF, SASA, RG, inter and intra H-bond, PCA, FEL, and MMBSA studies affirmed the ligand-protein and protein complex flexibility, compactness, binding energy, van der waals energy, and solvation dynamics. These results revealed the stability and the interaction of the ligand with the catalytic site of arginase 1 enzyme, triggering the study towards the VLU treatment.

Interconnections between the Cation/Alkaline pH-Responsive Slt and the Ambient pH Response of PacC/Pal Pathways in Aspergillus nidulans.

In the filamentous ascomycete Aspergillus nidulans, at least three high hierarchy transcription factors are required for growth at extracellular alkaline pH: SltA, PacC and CrzA. Transcriptomic profiles depending on alkaline pH and SltA function showed that pacC expression might be under SltA regulation. Additional transcriptional studies of PacC and the only pH-regulated pal gene, palF, confirmed both the strong dependence on ambient pH and the function of SltA. The regulation of pacC expression is dependent on the activity of the zinc binuclear (C6) cluster transcription factor PacX. However, we found that the ablation of sltA in the pacX- mutant background specifically prevents the increase in pacC expression levels without affecting PacC protein levels, showing a novel specific function of the PacX factor. The loss of sltA function causes the anomalous proteolytic processing of PacC and a reduction in the post-translational modifications of PalF. At alkaline pH, in a null sltA background, PacC72kDa accumulates, detection of the intermediate PacC53kDa form is extremely low and the final processed form of 27 kDa shows altered electrophoretic mobility. Constitutive ubiquitination of PalF or the presence of alkalinity-mimicking mutations in pacC, such as pacCc14 and pacCc700, resembling PacC53kDa and PacC27kDa, respectively, allowed the normal processing of PacC but did not rescue the alkaline pH-sensitive phenotype caused by the null sltA allele. Overall, data show that Slt and PacC/Pal pathways are interconnected, but the transcription factor SltA is on a higher hierarchical level than PacC on regulating the tolerance to the ambient alkalinity in A. nidulans.

A molybdenum-ciprofloxacin complex with an isopolyoxometalate having DNA binding and antibacterial activity

In this study, an antibacterial complex based on the quinolone antibacterial drug ciprofloxacin (CF) and a polyoxometalate was synthesized, Mo2O5(CF)2(CFd)2(β-Mo8O26)·5H2O (1). Complex 1 was characterized by elemental analysis and X-ray single-crystal diffraction. Single-crystal structural analysis revealed that 1 was made of β-Mo8 clusters, binuclear molybdenum clusters Mo2O5(CF)2(CFd)2, and water molecules. The antibacterial activity of 1 has been tested against three microorganisms (Staphylococcus aureus, Escherichia coli, and Bacillus subtilis strains); the antibacterial activities of 1 were higher than those of free CF at the same mass amounts. The interaction between 1 and calf thymus DNA (CT-DNA) was investigated using Uv-vis spectroscopy to determine the binding constants. The results indicated that intercalation is the probable mode of action, with 1 demonstrating higher binding constants (K b) to CT-DNA (1.8 × 105 M−1) compared to pure CF (4.9 × 104 M−1). These findings show that the implementation of molybdate for ciprofloxacin modification resulted in the formation of a metal complex with enhanced antibacterial activity over CF and significantly improving its binding affinity to DNA.

Investigation of inhibition kinetics of various plant extracts on polyphenol oxidase enzyme from Paulownia Tomentosa and binding mechanism by molecular docking

Polyphenol oxidase/tyrosinase enzyme, which contains binuclear copper clusters play an important role in melanogenesis and enzymatic browning. Therefore, its inhibitors can be attractive in cosmetics and medicinal industries as depigmentation agents and also in food and agriculture industries as antibrowning compounds. Our aim in this study is to find natural plant extracts that will inhibit the polyphenol oxidase enzyme. The inhibitory effects of Verbascum thapsus, Tanacetum vulgare, Solanum nigrum and Datura stramonium herbal plant extracts obtained from Kosovo on the polyphenol oxidase enzyme activity were investigated. Polyphenol oxidase from the Poulownia tomentosa plant was purified using the three-phase purification method. It is determined that T. vulgare extract showed the most effective inhibitory effect with 0.43 mg/mL IC50 value. In order to explain and support the binding mechanism of the best inhibitor extract, the phenolic content of the T. vulgare extract was determined by LC-MS/MS and the mechanism of the inhibitory effect was explained by performing a molecular docking study for the phenolic compounds it contained at the highest rate.

Asymmetric triply bridged lanthanide binuclear clusters with distinctly different magnetic behaviors

Isomorphic binuclear clusters Gd and Dy with antiferromagnetic and ferromagnetic couplings are separately exhibiting single-molecule magnetic behavior and strong magnetocaloric entropy.

Water-Soluble Polyoxometal Clusters of Molybdenum (V) with Pyrazole and Triazole: Synthesis and Study of Cytotoxicity and Antiviral Activity.

Among well-studied and actively developing compounds are polyoxometalates (POMs), which show application in many fields. Extending this class of compounds, we introduce a new subclass of polyoxometal clusters (POMCs) [Mo12O28(μ-L)8]4- (L = pyrazolate (pz) or triazolate (1,2,3-trz or 1,2,4-trz)), structurally similar to POM, but containing binuclear Mo2O4 clusters linked by bridging oxo- and organic ligands. The complexes obtained by ampoule synthesis from the binuclear cluster [Mo2O4(C2O4)2(H2O)2]2- in a melt of an organic ligand are soluble and stable in aqueous solutions. In addition to the detailed characterization in solid state and in aqueous solution, the biological properties of the compounds on normal and cancer cells were investigated, and antiviral activity against influenza A virus (subtype H5N1) was demonstrated.

Construction of 2D layered metal‐organic frameworks based on the norbornene‐derived ligand with fascinating magnetic and luminescent properties

AbstractThree new two‐dimensional metal‐organic frameworks (MOFs), namely [Cu3(NDIC)3 ⋅ C2H5OH ⋅ 2H2O]n (1), [Co2(NDIC)2 ⋅ 2 C3H7NO ⋅ H2O]n ⋅ nC2H5OH (2) and [(Zn3O)2(Zn(H2O)4)(NDIC)6 ⋅ C3H7NO ⋅ C2H5OH ⋅ C2H5O ⋅ 7H2O]n (3) based on the ligand 5‐norbonene‐2,3‐dicarboximide isophthalic acid (H2NDIC) have been synthesized under solvothermal condition, which have been further characterized by single crystal X‐ray diffraction analysis, powder X‐ray diffraction ( PXRD) elemental analysis, ICP, TG and FT‐IR spectroscopy. The ligand displayed distinctive coordination modes to connect mononuclear metal ion, binuclear and trinuclear metal clusters to generate different 2D layered structures in compound 1–3. Compound 1 shows KGM type network based on paddle‐wheel Cu2(COO)4 as secondary building units (SBUs). Compounds 2 and 3 have the undulating 2D (4, 4) SQL topology with the point symbol (44 ⋅ 62) based on Co2(COO)4 and Zn3(μ3‐O)(COO)4 as SBUs, respectively. The magnetic properties of compound 1–2 and the luminescent property of compound 3 and its fluorescent detection for Fe3+ has been investigated and discussed.

A Multifunctional Co-Based Metal-Organic Framework as a Platform for Proton Conduction and Ni trophenols Reduction.

The design and development of proton conduction materials for clean energy-related applications is obviously important and highly desired but challenging. An ultrastable cobalt-based metal-organic framework Co-MOF, formulated as [Co2(btzip)2(μ2-OH2)] (namely, LCUH-103, H2btzip = 4, 6-bis(triazol-1-yl)-isophthalic acid) had been successfully synthesized via the hydrothermal method. LCUH-103 exhibits a three-dimensional framework and a one-dimensional microporous channel structure with scu topology based on the binuclear metallic cluster {Co2}. LCUH-103 indicated excellent chemical and thermal stability; peculiarly, it can retain its entire framework in acid and alkali solutions with different pH values for 24 h. The excellent stability is a prerequisite for studying its proton conductivity, and its proton conductivity σ can reach up to 1.25 × 10-3 S·cm-1 at 80 °C and 100% relative humidity (RH). In order to enhance its proton conductivity, the proton-conducting material Im@LCUH-103 had been prepared by encapsulating imidazole molecules into the channels of LCUH-103. Im@LCUH-103 indicated an excellent proton conductivity of 3.18 × 10-2 S·cm-1 at 80 °C and 100% RH, which is 1 order of magnitude higher than that of original LCUH-103. The proton conduction mechanism was systematically studied by various detection means and theoretical calculations. Meanwhile, LCUH-103 is also an excellent carrier for palladium nanoparticles (Pd NPs) via a wetness impregnation strategy, and the nitrophenols (4/3/2-NP) reduction in aqueous solution by Pd@LCUH-103 indicated an outstanding conversion efficiency, high rate constant (k), and exceptional cycling stability. Specifically, the k value of 4-NP reduction by Pd@LCUH-103 is superior to many other reported catalysts, and its k value is as high as 1.34 min-1 and the cycling stability can reach up to 6 cycles. Notably, its turnover frequency (TOF) value is nearly 196.88 times more than that of Pd/C (wt 5%) in the reaction, indicating its excellent stability and catalytic activity.

Two diverse 3D 6-connected Cd(II)/Co(II) MOFs based on binuclear clusters as fluorescence sensors for detection of Fe3+, Cr2O72− and nitrobenzene

Two novel three-dimensional (3D) Cd(II)/Co(II) metal-organic frameworks (MOFs), [Cd2(seb)2(bbmb)(H2O)2]n (1) and {[Co2(seb)2(bbmb)2(H2O)]·0·5H2O}n (2), were synthesized under hydrothermal conditions based on sebacic acid (H2seb) and 4,4′-Bis(benzimidazol-1-ylmethyl) biphenyl (bbmb) ligands. Their crystal structures were structurally characterized by single-crystal X-ray diffraction. MOFs 1 and 2 both show a 3D framework based on binuclear Cd2 or Co2 clusters, respectively. In 1, the Cd2 clusters are linked by seb2- into a 2D corrugated layer. These layers are further connected by bbmb to generate a 3D structure with 6-connected (44·610·8) mab topology. In 2, the Co2 clusters form a 1D chain through the bbmb ligands, the chains are linked by seb2− into a 3D framework with 6-connected (48·54·63) bsn topology. Fluorescence sensing experiments show that 1 and 2 have good ability for detection of Fe3+, Cr2O72− and nitrobenzene (NB) with low detection limits as 5.83μM, 1.36μM and 2.70 × 10−7M for 1 and 6.19μM, 1.40μM and 2.90 × 10−7M for 2, respectively. Furthermore, the sensing mechanism was also investigated in detail by various detection means and theoretical calculations.

Structure, spectroscopy, and metal exchange among M(III) clusters with salicylidene-α-hydroxy acid chelates (M = Al, Ga, In, Fe)

The tetradentate salicylidene-α-hydroxy acid chelate, 3,5-diCl-Sal-AHA, was previously shown to form trinuclear clusters with the similarly-sized Fe(III) and Ga(III) ions, but a binuclear structure was observed with the much larger uranyl ion. To determine the structural effect of ionic size, complexes of 3,5-diCl-Sal-AHA with the smaller Al(III) ion and larger In(III) ion were prepared. X-ray data show that Al(III) forms a trinuclear cluster similar to those of Fe(III) and Ga(III). However, ESI-MS data show that Al(III) trinuclear clusters exist in equilibrium with binuclear clusters, with basic conditions favoring increased binuclear cluster formation. X-ray data from a crystal obtained from basic solution of Al(III) with 3,5-diCl-Sal-AHA show a binuclear, carbonato-bridged complex. ESI-MS data for the In(III) complex indicate that it forms a trinuclear cluster. The Fe(III), Ga(III), Al(III), and In(III) complexes all have strong circular dichroism spectra, while only the Al(III), Ga(III), and In(III) complexes are fluorescent. When the Group 13 metal complexes are treated with ferric chloride, Fe(III) displaces Al(III), Ga(III), and In(III) in aqueous methanol, but no metal exchange occurs in dry methanol.

Influence of Cmr1 in the Regulation of Antioxidant Function Melanin Biosynthesis in Aureobasidium pullulans.

We have successfully identified the transcription factor Cmr1 from the fungus Aureobasidium pullulans Hit-lcy3T, which regulates melanin biosynthesis genes. Bioinformatics analysis revealed that the Cmr1 gene encodes a protein of 945 amino acids, containing two Cys2His2 zinc finger domains and a Zn(II)2Cys6 binuclear cluster domain located at the N-terminus of Cmr1. To investigate the function of the Cmr1 gene, we performed gene knockout and overexpression experiments. Our results showed that Cmr1 is a key regulator of melanin synthesis in Hit-lcy3T, and its absence caused developmental defects. Conversely, overexpression of Cmr1 significantly increased the number of chlamydospores in Hit-lcy3T and improved melanin production. RT-qPCR analysis further revealed that overexpression of Cmr1 enhanced the expression of several genes involved in melanin biosynthesis, including Cmr1, PKS, SCD1, and THR1. Melanin extracted from the Hit-lcy3T was characterized using UV and IR spectroscopy. Furthermore, we assessed the antioxidant properties of Hit-lcy3T melanin and found that it possesses strong scavenging activity against DPPH·, ABTS·, and OH·, but weaker activity against O2-·. These findings suggest that Hit-lcy3T melanin holds promise for future development as a functional food additive.

Profiling the Pyrenophora tritici-repentis secretome: The Pf2 transcription factor regulates the secretion of the effector proteins ToxA and ToxB.

The global wheat disease tan spot is caused by the necrotrophic fungal pathogen Pyrenophora tritici-repentis (Ptr) which secretes necrotrophic effectors to facilitate host plant colonization. We previously reported a role of the Zn2 Cys6 binuclear cluster transcription factor Pf2 in the regulation of the Ptr effector ToxA. Here, we show that Pf2 is also a positive regulator of ToxB, via targeted deletion of PtrPf2 which resulted in reduced ToxB expression and defects in conidiation and pathogenicity. To further investigate the function of Ptr Pf2 in regulating protein secretion, the secretome profiles of two Δptrpf2 mutants of two Ptr races (races 1 and 5) were evaluated using a SWATH-mass spectrometry (MS) quantitative approach. Analysis of the secretomes of the Δptrpf2 mutants from in vitro culture filtrate identified more than 500 secreted proteins, with 25% unique to each race. Of the identified proteins, less than 6% were significantly differentially regulated by Ptr Pf2. Among the downregulated proteins were ToxA and ToxB, specific to race 1 and race 5 respectively, demonstrating the role of Ptr Pf2 as a positive regulator of both effectors. Significant motif sequences identified in both ToxA and ToxB putative promoter regions were further explored via GFP reporter assays.

Structural and Biochemical Insights into Post-Translational Arginine-to-Ornithine Peptide Modifications by an Atypical Arginase.

Landornamide A is a ribosomally synthesized and post-translationally modified peptide (RiPP) natural product with antiviral activity. Its biosynthetic gene cluster encodes─among other maturases─the peptide arginase OspR, which converts arginine to ornithine units in an unusual post-translational modification. Peptide arginases are a recently discovered RiPP maturase family with few characterized representatives. They show little sequence similarity to conventional arginases, a well-characterized enzyme family catalyzing the hydrolysis of free arginine to ornithine and urea. Peptide arginases are highly promiscuous and accept a variety of substrate sequences. The molecular basis for binding the large peptide substrate and for the high promiscuity of peptide arginases remains unclear. Here, we report the first crystal structure of a peptide arginase at a resolution of 2.6 Å. The three-dimensional structure reveals common features and differences between conventional arginases and the peptide arginase: the binuclear metal cluster and the active-site environment strongly resemble each other, while the quaternary structures diverge. Kinetic analyses of OspR with various substrates provide new insights into the order of biosynthetic reactions during the post-translational maturation of landornamide A. These results provide the basis for pathway engineering to generate derivatives of landornamide A and for the general application of peptide arginases as biosynthetic tools for peptide engineering.

Towards Arginase Inhibition: Hybrid SAR Protocol for Property Mapping of Chlorinated N-arylcinnamamides.

A series of seventeen 4-chlorocinnamanilides and seventeen 3,4-dichlorocinnamanilides were characterized for their antiplasmodial activity. In vitro screening on a chloroquine-sensitive strain of Plasmodium falciparum 3D7/MRA-102 highlighted that 23 compounds possessed IC50 < 30 µM. Typically, 3,4-dichlorocinnamanilides showed a broader range of activity compared to 4-chlorocinnamanilides. (2E)-N-[3,5-bis(trifluoromethyl)phenyl]-3-(3,4-dichlorophenyl)prop-2-en-amide with IC50 = 1.6 µM was the most effective agent, while the other eight most active derivatives showed IC50 in the range from 1.8 to 4.6 µM. A good correlation between the experimental logk and the estimated clogP was recorded for the whole ensemble of the lipophilicity generators. Moreover, the SAR-mediated similarity assessment of the novel (di)chlorinated N-arylcinnamamides was conducted using the collaborative (hybrid) ligand-based and structure-related protocols. In consequence, an 'averaged' selection-driven interaction pattern was produced based in namely 'pseudo-consensus' 3D pharmacophore mapping. The molecular docking approach was engaged for the most potent antiplasmodial agents in order to gain an insight into the arginase-inhibitor binding mode. The docking study revealed that (di)chlorinated aromatic (C-phenyl) rings are oriented towards the binuclear manganese cluster in the energetically favorable poses of the chloroquine and the most potent arginase inhibitors. Additionally, the water-mediated hydrogen bonds were formed via carbonyl function present in the new N-arylcinnamamides and the fluorine substituent (alone or in trifluoromethyl group) of N-phenyl ring seems to play a key role in forming the halogen bonds.

Mechanochemical Activation of Superradiance in Paramagnetic Polymer Composites.

The review examines the effect of radio-frequency superradiance during pulsed mechanochemical activation of polymer composites under high pressure. Mechanochemical activation is implemented in three modes: (a) rheological explosion of polymer composite under rapid uniaxial compression, when an elastic wave pulse occurs in a polymer composite sample and implements the physico-chemical transformations leading to the occurrence of a superradiance pulse; (b) parametric mode, when an elastic wave pulse is introduced from the outside through a waveguide into a composite sample; (c) the mode of rapid pressure release, which also leads to the occurrence of a superradiance pulse. Paramagnetic polymer composites-namely polystyrene-binuclear clusters Co(QH)2-O-Co(QH)2 or Mn(QH)2-O-Mn(QH)2, where QH is a ligand based on QH2-3,6-di-tert-butylpyrocatechin)-are considered as objects implementing such processes. These binuclear clusters exhibit the Dzyaloshinskii-Moriya effect, and polymer composites based on them exhibit multiferroic properties. A composite of a molecular magnet in polystyrene matrix (Eu(III)(SQ)3·bipy complex with four unpaired electrons on Eu(III) and on SQ ligands; SQ is 3,6-di-tert-butylquinolate paramagnetic ligand) is also considered. The binuclear clusters and europium complexes form 2D nano-objects in the polymer matrix with a diameter of 50-100 nm and a thickness of ~ 1-2 nm. The review considers the formalisms of Dicke, Lorentz, Landau-Lifshitz-Blombergen and Havriliak-Negami equations, which make it possible to conduct a time-frequency analysis of these processes, to obtain data on the relaxation processes of spin and charge density in objects responsible for the process of radio-frequency superradiation. It is also shown that the analysis of electron spin resonance data allows us to provide a probable quantum chemical scheme for the implementation of the radio-frequency superradiance process. The phenomenon of superradiation has a great deal of potential in such areas as energy-saving technologies, wireless power transmission and storage devices. The technique of studying fast mechanochemical processes considered in the review allows us to investigate the mechanisms of interaction of magnetic and electrical subsystems in multiferroics and molecular magnets, which expands the scientific base for the creation of new functional materials and enables the solving of related problems of condensed matter physics.