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Spatial cables in suspension bridges may twist between two adjacent suspension points due to transverse tension. To determine the spatial torsion angle of the cables, a scale-reduced suspender bridge model was fabricated and tested in this study. The cable torsion angles of the bridge model under different loading cases were obtained and presented. Theoretical methods (e.g., the coordinate method and the angle method) to calculate the spatial cable torsion angle in the suspender bridge were developed by analyzing the deforming characteristics of the suspender cables. The feasibility and predictive accuracy of the proposed methods were assessed using the experimental results. Results show that the proposed coordinate and angle methods produced similar torsion angles for the main cables, showing a maximum relative error of 10.4 %. Compared to the coordinate method's complex data transformation and measurement procedures, the angle method is more convenient, efficient, and easier to calculate the torsion angle of the main cable. Despite the capability of calculating the spatial cable torsion angles, the coordinate method also exhibits advanced capability in determining the geometric curves of the main cable under different spatial angles. [ABSTRACT FROM AUTHOR]

Recent simulation studies have revealed a wealth of distinct crystal polymorphs encountered in the self-organization of polymer systems driven by entropy or free energy. The present analysis, based on the concept of self-avoiding random walks (SAWs) on crystal lattices, is useful to calculate upper bounds for the entropy difference of the crystals that are formed during polymer crystallization and thus to predict the thermodynamic stability of distinct polymorphs. Here, we compare two pairs of crystals sharing the same coordination number, ncoord: hexagonal close-packed (HCP) and face centered cubic (FCC), both having ncoord = 12 and the same packing density, and the less dense simple hexagonal (HEX) and body centered cubic (BCC) lattices, with ncoord = 8. In both cases, once a critical number of steps is reached, one of the crystals shows a higher number of SAWs compatible with its geometry. We explain the observed trends in terms of the bending and torsion angles as imposed by the geometric constraints of the crystal lattice. [ABSTRACT FROM AUTHOR]

High‐contrast mechano‐responsive luminescence (MRL) materials with mechano‐induced emission enhancement properties are fascinating candidates but few, for applications in rewritable media and recording devices. Here, an interesting design strategy of "Y‐shape" donor‐acceptor (D−A) type molecules for high‐contrast MRL materials was presented, based on substituted diphenylamine donor and planar acceptor. Interestingly, their D−A torsion angles are small in crystals but increased after ground, resulted in planar and twist intramolecular charge transfer (PICT and TICT) states, respectively. Therefore, high‐contrast MRL switching between weak blue (450 nm) fluorescence and bright yellow (552 nm) thermally activated delayed fluorescence (TADF) can be achieved for compound TXDO (4,4′‐dimethoxydiphenylamine donor), which photoluminescence quantum yield increased from 2.8 % to 54.7 % after ground. Most importantly, the two independent D−A conjugation dihedral angles are actually independent in the "Y‐shape" molecules. Especially for compound TXDT (4,4′‐di‐tert‐butyldiphenylamine donor), its crystal exhibited both PICT and TICT processes inside, resulted from the different dihedral angles of 11.8° and 35.5°, respectively. The TXDT crystal thus showed dual‐peak emission, including both TICT fluorescence and PICT room‐temperature phosphorescence. Therefore, this strategy of "Y‐shape" D−A type molecules provide a new approach to design advanced luminescent materials with mechano‐induced TADF feature, for high‐contrast MRL and single‐component white luminescence. [ABSTRACT FROM AUTHOR]

The performances of turbine blades have a significant impact on the energy conversion efficiency of vertical solar power plants. In the present study, such a relationship is assessed by considering two kinds of airfoil blades, designed by using the Wilson theory. In particular, numerical simulations are conducted using the SST K − ω model and assuming a wind speed of 3–6 m/s and seven or eight blades. The two airfoils are the NACA63121 (with a larger chord length) and the AMES63212; It is shown that the torsion angle of the former is smaller, and its wind drag ratio is larger; furthermore, the resistance is increased by about 66.3% on average. Within the scope of the study, the results show that the NACA63212 airfoil is better than the AMES63212 airfoil in terms of power, with an average improvement of about 2.8%. The simulation results have a certain guiding significance for selecting turbine blade airfoils and improving turbine efficiency. [ABSTRACT FROM AUTHOR]

In the title compound, C19H15NO, the dihedral angle between the benzene rings of the carbazole moiety is 1.73 (12)° and the methoxy-substituted phenyl ring deviates from the mean plane of the carbazole grouping (r.m.s. deviation = 0.020 Å) by 56.78 (8)°. In the crystal, weak C—H...π interactions link the molecules. The two-dimensional fingerprint plots derived from the Hirshfeld surface indicate that H...H (51.2%) and C...H/H...C (39.9%) contacts dominate the packing.

Sandwich round tubes are widely used in vehicle engineering and aerospace fields because of their light weight, low cost and high energy absorption rate. In order to improve the crashworthiness of the sandwich round tube, an axial impact simulation study was conducted using the finite element software Ansys to analyze the effects of the number of ribs, wall thickness and inner circle diameter on its crashworthiness. The structure of the sandwich tube was optimized by combining the response surface method and the second generation genetic algorithm (NSGA-II), and finally the structure was twisted to investigate the effect of twisting angle on the impact resistance performance. The results show that the wall thickness has the greatest effect on the impact resistance, and the inner circle diameter has basically no effect on the peak compression force. The torsional core tube can increase the specific energy absorption without increasing the peak compression force, and the impact resistance performance is significantly improved. The best effect is achieved when the torsional angle is 45°, which is 10. 75% higher than that before torsion, providing a new method for the design of impact resistance of the core tube. [ABSTRACT FROM AUTHOR]

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The structural plasticity of proteins at the molecular level is largely dictated by backbone torsion angles, which play a critical role in ligand recognition and binding. To establish the anion-induced cooperative arrangement of the main-chain (mc) torsion, herein, we analyzed a set of naturally occurring CαNN motifs as "static models" for their anion-binding competence through docking and molecular dynamics simulations and decoded its torsion angle influenced mc-driven anion recognition potential. By comparing a pool of 20 distinct sets of CαNN motif with identical sequences in their "anion bound/present, aP" and "anion free/absent, aA" versions, we could discern that there exists a positive correlation between the "difference of anion residence time (ΔR T )" and "difference among the main-chain torsion angle" of the aP and aA population. Notably, the anion interaction with CαNNs is locally energetically favorable even in a context-free non-proteinaceous environment and if the difference of the mc-torsion angles involving the Cα -1 , N 0 , N 1 residues for a population is higher between the aP and aA state, the difference among the ligand R T is also greater. At the atomistic level, the accommodation of anion is highly synergistic and cooperatively sways the interacting mc-atom torsions. By comparing the clustering of H-bonding patterns, the free energy of binding, and R T in both states, we provide evidence that to establish favorable thermodynamics and kinetics of ligand accommodation in these short structural motifs, proper reorientation of local-mc governed by torsions is a prerequisite. Our findings position the CαNN motif as a promising scaffold for peptidomimetic design and emphasize the critical role of loop region dynamics in protein structure-function relationships., (© 2025 Wiley Periodicals LLC.)

The seismic behavior of the independent type of a stone masonry loess cave (SMLC) is examined. A tri-directional shake table test was employed on 1:4 reduced-scale specimen of SMLC. The specimen represented a typical traditional dwelling of the loess region in China, consisting of unreinforced masonry walls and inner loess, without any seismic treatment. The dynamic parameters directly measured by the test include the acceleration response, displacement response of each key position of the stone masonry loess cave, and the detailed record of the damage form of the structure under each loading. The analysis results indicated that the simplified model design method not only satisfied the main similarity relationship of the reduced-scale structure shaking table test, but also achieved excellent test results. Through the calculation results to determine the torsion angle of the node and the deformation between the layers, corresponding strengthening measures could be proposed for the life extension protection of this traditional building. Finally, according to the analysis of the test results, the damage state and damage level of the prototype of the SMLC is established. [ABSTRACT FROM AUTHOR]

Some expensive and challenging laboratory or field tests must be done to obtain the engineering properties of rocks. For avoiding time and cost consumption, some researchers have used simple tests to estimate some engineering properties. The friction-transfer test is partially destructive and can estimate the rock uniaxial compressive strength (UCS) using experimental equations or a previously prepared calibration graph. In this study, some engineering properties of seven types of limy rocks from Qom formation, collected from Hamadan province, were estimated using friction-transfer test results. Regression analysis between friction-transfer and physical properties tests show that the best relationship is between porosity (n%) and friction-transfer value (T) and torsion angle (θ) (R2 = 0.74). Friction-transfer engineering property regression analysis shows that the best relation is obtained between Brazilian tensile strength (BTS) and T, θ, because of the higher R2 (0.80). Relatively high coefficients of the determination indicate that the friction transfer can successfully predict the UCS of rocks. A conversion factor equal to 0.48 was obtained for estimating UCS by T values for this study data. Highlights: •The friction-transfer test is partially destructive, which can be used to estimate the rock uniaxial compressive strength indirectly. •Regression analysis shows that the best relation obtained between Brazilian Tensile Strength and Friction-transfer, torsion angle, because of the higher R2 (0.80). •Relatively high coefficients of the determination indicate that the friction-transfer can successfully predict the UCS of rocks. •The conversion factor equal to 0.48 was obtained for estimating uniaxial compressive strength by friction-transfer values for this study data. [ABSTRACT FROM AUTHOR]

There is little investigation into the impact of molecular conformation on device efficiency and degradation of boron‐nitrogen thermally activated delayed fluorescence emitters (BN‐TADF). Herein, three highly‐efficient green BN‐TADF emitters have been designed to unveil the impact of peripheral phenyl groups on device efficiencies and lifetimes. Compared to BN‐PhOH with the lowest EQEmax of 19 %, BN‐PhOCH3 and BN‐PhN(CH3)2 have achieved strongly enhanced EQEmax of 25.6 % and 24.1 %, respectively. Importantly, the device lifetimes (LT50) are dramatically improved from 1.7 h of BN‐PhOH to 4.4 h of BN‐PhOCH3 and 7.7 h of BN‐PhN(CH3)2 without encapsulation. According to in situ Raman spectroscopy and simulations, BN‐PhN(CH3)2 of less conformation change after aging exhibits the best photostability. It is proposed that the torsion angle change between the BN core and the peripheral phenyl group results in BN‐TADF degradation. This knowledge means precisely tuning peripheral groups of BN‐TADF can achieve both higher device efficiencies and longer lifetimes. [ABSTRACT FROM AUTHOR]

Sesquiterpene lactones, a class of natural compounds abundant in the Asteraceae family, have gained attention owing to their diverse biological activities, and particularly their anti-proliferative effects on human cancer cells. In this study, we systematically investigated the structure-activity relationship of ten sesquiterpene lactones with the aim of elucidating the structural determinants for the STAT3 inhibition governing their anti-proliferative effects. Our findings revealed a significant correlation between the STAT3 inhibitory activity and the anti-proliferative effects of sesquiterpene lactones in MDA-MB-231 breast cancer cell lines. Among the compounds tested, alantolactone and isoalantolactone emerged as the most potent STAT3 inhibitors, highlighting their potential as candidates for anticancer drug development. Through protein-ligand docking studies, we revealed the structural basis of STAT3 inhibition by sesquiterpene lactones, emphasizing the critical role of hydrogen-bonding interactions with key residues, including Arg609, Ser611, Glu612, and Ser613, in the SH2 domain of STAT3. Furthermore, our conformational analysis revealed the decisive role of the torsion angle within the geometry-optimized structures of sesquiterpene lactones in their STAT3 inhibitory activity ( R =0.80, p <0.01). These findings not only provide preclinical evidence for sesquiterpene lactones as promising phytomedicines against diseases associated with abnormal STAT3 activation, but also highlight the importance of stereochemical aspects in their activity.

Molecular structures of (R)-2,2′-dimethyl-1,1′-binaphthyl [monoclinic, a = 11.24420 (11), b = 10.56190 (9), c = 13.27180 (13) Å, β = 90.7041 (9)°, space group P21] and (±)-2-bromomethyl-2′-dibromomethyl-1,1′-binaphthyl [triclinic, a = 9.4637 (14), b = 9.9721 (18), c = 9.9922 (19) Å, α = 100.093 (5), β = 97.141 (5), γ = 92.585 (4)°, space group P-1] are reported and compared with those of other simple 2,2′-disubstituted-1,1′-binaphthyls. Inter-ring bond length and torsion angles are compared with other simple 2,2′-disubstututed-1,1′-binaphthyls. [ABSTRACT FROM AUTHOR]

The hoisting rope in the kilometer-deep coal mine exhibits the tension–torsion fretting fatigue behaviors of inclined crossed steel wires in acid solution. Distinct contact load and torsion angles of steel wires in the rope cause different crack propagation behaviors, which greatly affect the fatigue lives of steel wires. Therefore, the effects of contact load and torsion angle on the crack propagation behaviors of inclined crossed steel wires during tension–torsion fretting fatigue in acid solution were investigated in the present study. The three-dimensional X-ray tomographic micro-imaging system was used to reveal evolutions of crack profiles and crack propagation depths during the test. The evolution of friction coefficient between steel wires during the test is presented. The three-dimensional white light interference microscope, electrochemical analyzer, and scanning electron microscope were employed to investigate the wear depth profiles, Tafel polarization curves and impedance spectra, and wear scar morphologies, respectively, of steel wires. Effects of contact load and torsion angle on crack propagation behaviors of inclined crossed steel wires during the tests were explored through analyses of friction and wear mechanisms and electrochemical corrosion damage. The results show that as the contact load and torsion angle increase, the crack propagation depth and rate of steel wire both increase and the fatigue life of steel wire decreases. Those are mainly attributed to the increases in the average tangential force between steel wires, wear depth, electrochemical corrosion tendency, and surface damage of steel wire as well as the decrease in corrosion resistance. [ABSTRACT FROM AUTHOR]

Abstract Generating low-energy molecular conformers is a key task for many areas of computational chemistry, molecular modeling and cheminformatics. Most current conformer generation methods primarily focus on generating geometrically diverse conformers rather than finding the most probable or energetically lowest minima. Here, we present a new stochastic search method called the Bayesian optimization algorithm (BOA) for finding the lowest energy conformation of a given molecule. We compare BOA with uniform random search, and systematic search as implemented in Confab, to determine which method finds the lowest energy. Energetic difference, root-mean-square deviation, and torsion fingerprint deviation are used to quantify the performance of the conformer search algorithms. In general, we find BOA requires far fewer evaluations than systematic or uniform random search to find low-energy minima. For molecules with four or more rotatable bonds, Confab typically evaluates $$10^{4}$$ 104 (median) conformers in its search, while BOA only requires $$10^{2}$$ 102 energy evaluations to find top candidates. Despite using evaluating fewer conformers, 20–40% of the time BOA finds lower-energy conformations than a systematic Confab search for molecules with four or more rotatable bonds.

Aiming at lacking of effective, reliable and full-scale torsion angle calibration device for calibration of torsion angle of the active rotating clamp of torsion testing machine which was needed to be calibrated regularly, the structure and working principle of the torsion testing machine were researched, and a calibration system for torsion angle based on photoelectric shaft encoder was proposed. The structure of the calibration system was designed, and its workflow was established, and the calibration system for torsion angle based on photoelectric shaft encoder was built. The torsion angle of torsion testing machine was calibrated by using the calibration system. The calibration result was evaluated for its uncertainty. And the relative error calculation and the repeatability calculation were also carried out for the calibration result. The results indicate that the calibration system for torsion angle has the characteristics of simple structure, convenient operation and stable performance, which can not only meet the measurement requirement of torsion angle in JJG269 - 2006 Torsion Testing Machine Verification Regulations, but also provide a reference for the development and construction of calibration device for the torsion angle of torsion testing machine with higher accuracy and higher efficiency. [ABSTRACT FROM AUTHOR]

The propeller blades used in unmanned multi-rotor aircraft are mainly fixed-wing propellers, but their aerodynamic environments are not the same. The parametric modeling of the original blades is established by using the inverse reconfiguration technique and based on CFD technology the design of the parametric reference model’s torsional angle distribution and the leaf-type stacking pattern in the vertical flight state is optimized. The results show that the efficiency of the blade in the hovering state is greatly improved within the power allowable range.

Taking advantage of the known planarity of the N‐acetyl group of N‐acetylglucosamine, an analysis of the quality of carbohydrate structures found in the protein databank was performed. Few obvious defects of the local geometry of the carbonyl group were observed. However, the N‐acetyl group was often found in the less favorable cis conformation (12% of the cases). It was also found severely twisted in numerous instances, especially in structures with a resolution poorer than 1.9 Å determined between 2000 and 2015. Though the automated PDB‐REDO procedure has proved able to improve nearly 85% of the structural models deposited to the PDB, and does prove able to cure most severely twisted conformations of the N‐acetyl group, it fails to correct its high rate of cis conformations. More generally, for structures with a resolution poorer than 1.6 Å, it produces N‐acetylglucosamine models in slightly poorer agreement with experimental data, as measured using real‐space correlation coefficients. Significant improvements are thus still needed, at least as far as this carbohydrate structure is concerned. [ABSTRACT FROM AUTHOR]

Predicting structural properties of proteins plays a key role in predicting the 3D structure of proteins. In this study, new structural profile matrices (SPM) are developed for protein secondary structure, solvent accessibility and torsion angle class predictions, which could be used as input to 3D prediction algorithms. The structural templates employed in computing SPMs are detected by eight alignment methods in LOMETS server, gap affine alignment method, ScanProsite, PfamScan, and HHblits. The contribution of each template is weighted by its similarity to target, which is assessed by several sequence alignment scores. For comparison, the SPMs are also computed using Homolpro, which uses BLAST for target template alignments and does not assign weights to templates. Incorporating the SPMs into DSPRED classifier, the prediction accuracy improves significantly as demonstrated by cross-validation experiments on two difficult benchmarks. The most accurate predictions are obtained using the SPMs derived by threading methods in LOMETS server. On the other hand, the computational cost of computing these SPMs was the highest. [ABSTRACT FROM AUTHOR]

Presented here are the synthesis, characterization and study (using single crystal X‐ray diffraction, Raman scattering, quantum mechanics calculations) of the structures of a series of biphenyls substituted in positions 3, 3′, 4 and 4′ with a variety of R (R = methyl, acetyl, hexyl) groups connected to the biphenyl core through oxygen atoms. The molecular conformation, particularly the torsion angle between aromatic rings has been extensively studied both in the solid as well as in the liquid state. The results show that the compounds appearing as rigorously planar in the solid present instead a twisted conformation in the melt. The solid versus melt issue strongly suggests that the reasons for planarity are to be found in the packing restraints. A 'rule of thumb' is suggested for the design of biphenyls with different molecular conformations, based on the selection of the OR substituent. [ABSTRACT FROM AUTHOR]

Abstract Background Protein structure can be described by backbone torsion angles: rotational angles about the N-Cα bond (φ) and the Cα-C bond (ψ) or the angle between Cαi-1-Cαi-Cαi + 1 (θ) and the rotational angle about the Cαi-Cαi + 1 bond (τ). Thus, their accurate prediction is useful for structure prediction and model refinement. Early methods predicted torsion angles in a few discrete bins whereas most recent methods have focused on prediction of angles in real, continuous values. Real value prediction, however, is unable to provide the information on probabilities of predicted angles. Results Here, we propose to predict angles in fine grids of 5° by using deep learning neural networks. We found that this grid-based technique can yield 2–6% higher accuracy in predicting angles in the same 5° bin than existing prediction techniques compared. We further demonstrate the usefulness of predicted probabilities at given angle bins in discrimination of intrinsically disorder regions and in selection of protein models. Conclusions The proposed method may be useful for characterizing protein structure and disorder. The method is available at http://sparks-lab.org/server/SPIDER2/ as a part of SPIDER2 package.

The hoisting rope in the kilometer-deep coal mine exhibits the tension–torsion fretting fatigue behaviors of inclined crossed steel wires in acid solution. Distinct contact load and torsion angles of steel wires in the rope cause different crack propagation behaviors, which greatly affect the fatigue lives of steel wires. Therefore, the effects of contact load and torsion angle on the crack propagation behaviors of inclined crossed steel wires during tension–torsion fretting fatigue in acid solution were investigated in the present study. The three-dimensional X-ray tomographic micro-imaging system was used to reveal evolutions of crack profiles and crack propagation depths during the test. The evolution of friction coefficient between steel wires during the test is presented. The three-dimensional white light interference microscope, electrochemical analyzer, and scanning electron microscope were employed to investigate the wear depth profiles, Tafel polarization curves and impedance spectra, and wear scar morphologies, respectively, of steel wires. Effects of contact load and torsion angle on crack propagation behaviors of inclined crossed steel wires during the tests were explored through analyses of friction and wear mechanisms and electrochemical corrosion damage. The results show that as the contact load and torsion angle increase, the crack propagation depth and rate of steel wire both increase and the fatigue life of steel wire decreases. Those are mainly attributed to the increases in the average tangential force between steel wires, wear depth, electrochemical corrosion tendency, and surface damage of steel wire as well as the decrease in corrosion resistance.

Xylobiose (β-d-xylopyranosyl-(1 → 4)-d-xylopyranose) could be regarded as the shortest and simplest xylan, a member of the hemicellulose family of molecules that interact with cellulose and lignin in plants. Those interactions, important in plant growth as well as in utilization of wood and cereal grains, depend partly on the molecular shapes. In this work, xylan conformations were modeled with xylobiose using the same density functional theory (DFT) quantum mechanics approach used previously for cellobiose, with both vacuum and solvated models. The region of lowest energy for the solvated model (but not for the vacuum model) accommodates the experimentally observed left-handed, threefold helical shape of xylan hydrate as well as most di- and oligosaccharide structures from the Cambridge Structural Database and the Protein Data Bank. We compared the energy surfaces of xylobiose and cellobiose to learn the effect of the CH2OH group of cellobiose. That comparison, and a similar comparison of non-hydroxyl bearing analogs, showed that the C6 group increased the relative energies of structures having ψC5 values between − 100° and + 40°. The energy map for the solvated, non-hydroxyl bearing xylobiose analog was surprisingly predictive of the observed experimental crystal structures. Comparisons with xylobiose maps from the literature are also presented. Although hydrogen bonding is frequently invoked to explain changes in carbohydrate structure and properties, condensed-phase experimental structures were predicted better by modeling methods with diminished strengths of hydrogen bonds. That suggests they are relatively unimportant in influencing the structure of β-(1 → 4)-linked molecules, in agreement with other work in the literature. [ABSTRACT FROM AUTHOR]

Proteomics is the extensive investigation of proteins which has empowered the recognizable proof of consistently expanding quantities of protein. Proteins are necessary part of living life form, with numerous capacities. The proteome is the complete arrangement of proteins that are created or altered by a life form or framework of the organism. Proteome fluctuates with time and unambiguous prerequisites, or stresses, that a cell or organism experiences. Proteomics is an interdisciplinary area that has derived from the hereditary data of different genome ventures. Much proteomics information is gathered with the assistance of high throughput techniques, for example, mass spectrometry and microarray. It would regularly take weeks or months to analyze the information and perform examinations by hand. Therefore, scholars and scientific experts are teaming up with computer science researchers and mathematicians to make projects and pipeline to computationally examine the protein information. Utilizing bioinformatics procedures, scientists are prepared to do quicker investigation and protein information storing. The goal of this paper is to brief about the review of machine learning procedures and its application in the field of proteomics. • Study of machine learning algorithm, proteomics,artificial neural network. • Study of machine learning algorithm for protein secondary structure prediction. • Study of machine learning algorithm for protein tertiary structure prediction. • Study of machine learning algorithm for protein torsion angle prediction. • Study of machine learning algorithm for protein loop modeling. [ABSTRACT FROM AUTHOR]

This paper presents a coupled thermo-mechanical analytical solution for friction-assisted tube-straining method. Heat transfer, velocity field, and energy equations were derived for this process and were coupled into an incremental analysis. Derived equations were solved in many time intervals with mobile boundary conditions and heat input. Mechanical and thermal parts of the presented model were initially examined independently, then were coupled and compared with finite element method and experimental tests. Experimental tests were executed on commercially pure copper to monitor temperature field, extrusion force, and deformation behavior. Torsion angle of the processed tube was predicted by the computational model and was verified with finite element method and experimental test. [ABSTRACT FROM AUTHOR]

Graphical abstract We report herein a unique experimental realization of predicted ferromagnetic coupling for near orthogonal bridged pyrazole units, with corroborating theoretical Broken Symmetry-DFT calculations. Abstract The syntheses, crystal structures, magnetic properties and DFT calculations of four Cu(II) complexes of the formula [{Cu(2,2′-bpy)(HCPCA)}(H 2 O) 2 ]·3H 2 O (1), [Cu(dmbp)(HCPCA)] (2), [Cu(phen)(HCPCA)]·H 2 O (3) and [Cu(phen)(CPCA)] 2 ·DMF (4) [H 2 CPCA = 3-(3-carboxyphenyl)-1H-pyrazole-5-carboxylic acid, phen = 1,10-phenanthroline] are reported here. Our main focus was to design ta ferromagnetic complex and therefore concentrated on the mononuclear and binuclear copper complexes 3 and 4. In complex 3 the pyrazole unit of the H 2 CPCA ligand binds (as HCPCA-) in a monodentate fashion to form the mononuclear complex, and in complex 4 the pyrazole unit of the H 2 CPCA ligand binds (as CPCA2−) in a bidentate fashion to form a binuclear complex, creating a near orthogonal orientation between the two Cu(II) ions. Temperature dependent magnetic susceptibility measurements show the appearance of weak ferromagnetic interactions for complex 4 , whereas complex 3 shows paramagnetic behavior. The results are in excellent agreement with theoretical Broken Symmetry-DFT calculations. [ABSTRACT FROM AUTHOR]

The first pyroborate in the Li 2 O-MgO-B 2 O 3 system, Li 3.366 Mg 0.317 B 2 O 5 , has been synthesized via high temperature solution method. The crystal structure can be described as isolated B 2 O 5 units connecting with the Li(2)O 5 chains to generate the 2 ∞ [Li 2 (2)B 2 O 5 ] layers, which condense alone a -axis, and the co-occupied Li(1)/Mg atoms fill into the voids between the layers. Interestingly, edge- and face-sharing Li(2)O 5 polyhedra are rarely found in Li 3.366 Mg 0.317 B 2 O 5 and its maternal compound β -Li 4 B 2 O 5 . Moreover, torsion and dihedral angles between two BO 3 triangles of B 2 O 5 in Li 4−2x Mg x B 2 O 5 (x = 0, 0.317, 2) are investigated to explore the structure regulation via introduction of the Mg 2+ cation. The structure refinement, thermal stability and infrared spectrum are presented in detail. [ABSTRACT FROM AUTHOR]