Pyramidal Configuration Research Articles

Structural and Biological Comparative Studies on M(II)-Complexes (M = Co, Mn, Cu, Ni, Zn) of Hydrazone-s-Triazine Ligand Bearing Pyridyl Arm

The molecular and supramolecular structures of some M(II) complexes (M = Co, Mn, Cu, Ni, Zn) with a hydrazone-s-triazine ligand (BMPyTr) were discussed based on single crystal X-ray diffraction (SCXRD), Hirshfeld and DFT analyses. A new Co(II) complex of the same ligand was synthesized and its structure was confirmed to be [Co(BMPyTr)Cl2]·H2O based on FTIR and UV–Vis spectra, elemental analysis and SCXRD. The geometry around Co(II) was a distorted square pyramidal configuration (τ5 = 0.4), where Co(II) ion is coordinated to one NNN-tridentate ligand (BMPyTr) and two Cl- ions. A Hirshfeld analysis indicated all potential contacts within the crystal structure, where the percentages of O⋯H, N⋯H, C⋯H, and H⋯H contacts in one unit were 11.2, 9.3, 11.4, and 45.9%, respectively, while the respective values for the other complex unit were 10.3, 8.8, 10.6, and 48.0%. According to DFT calculations, the presence of strongly coordinating anions, such as Cl-, in addition to the large metal ion size, were found to be the main reasons for the small M-BMPyTr interaction energies in the cases of [Mn(BMPyTr)Cl2] (260.79 kcal/mol) and [Co(BMPyTr)Cl2]·H2O (307.46 kcal/mol) complexes. Interestingly, the Co(II) complex had potential activity against both Gram-positive (S. aureus and B. subtilis) and Gram-negative (E. coli and P. vulgaris) bacterial strains with inhibition zone diameters of 13, 15, 16, and 18 mm, respectively. Also, the new [Co(BMPyTr)Cl2]·H2O (IC50 = 131.2 ± 6.8 μM) complex had slightly better cytotoxic activity against HCT-116 cell line compared to BMPyTr (145.3 ± 7.1 μM).

Photochemical Origins of Iron Flocculation in Acid Mine Drainage.

Acid mine drainage (AMD) raises a global environmental concern impacting the iron cycle. Although the formation of Fe(III) minerals in AMD-impacted waters has previously been reported to be regulated by biological processes, the role of abiotic processes remains largely unknown. This study first reported that a photochemical reaction coupled with O2 significantly accelerated the formation of Fe(III) flocculates (i.e., schwertmannite) in the AMD, as evidenced by the comparison of samples from contaminated sites across different natural conditions at latitudes 24-29° N. Combined with experimental and modeling results, it is further discovered that the intramolecular oxidation of photogenerated Fe(II) with a five-coordinative pyramidal configuration (i.e., [(H2O)5Fe]2+) by O2 was the key in enhancing the photooxidation of Fe(II) in the simulated AMD. The in situ attenuated total reflectance-Fourier transform infrared spectrometry (ATR-FTIR), UV-vis spectroscopy, solvent substitution, and quantum yield analyses indicated that, acting as a precursor for flocculation, [(H2O)5Fe]2+ likely originated from both the dissolved and colloidal forms of Fe(III) through homogeneous and surface ligand-to-metal charge transfers. Density functional theory calculations and X-ray absorption spectroscopy results further suggested that the specific oxidation pathways of Fe(II) produced the highly reactive iron species and triggered the hydrolysis and formation of transient dihydroxo dimers. The proposed new pathways of Fe cycle are crucial in controlling the mobility of heavy metal anions in acidic waters and enhance the understanding of complicated iron biochemistry that is related to the fate of contaminants and nutrients.

Designing of some VO(II), Co(II) and Hg(II) Schiff base complexes: Synthesis, structure elucidation, anticancer and biopesticidal activities, DFT and docking approaches

New VO(II), Co(II) and Hg(II) chelates of bi- or tetradentate isatin based ligand i.e.:-2-(((E)-2-oxo-1,4-dihydrocyclohepta [b]pyrrol-3(2H)-ylidene)amino)-N-(8-((1-(2-((E)-2-oxoindolin-3-phenyl)vinyl) amino) naphthalen-1-yl) benzamide (H2L) were synthesized and well characterized. The reaction between N,N′-(naphthalene-1,8-diyl)bis(2-aminobenzamide) and di-oxazine-2,4 dione (isatin) yielded the Schiff base (H2L). The compounds have been identified by different physicochemical and spectroscopic approaches and DFT as well. From all measurements square pyramidal, distorted octahedral or square planar configurations have been suggested for the chelates 1, 2 and 3, respectively. The Coats-Redfern equations were used to calculate and define the dynamics properties of decomposition stages from TGA (Ea, A, ΔH*, ΔS*, and ΔG*). The in vitro anticancer property of the obtained compounds towards human hepato (HepG2) and human breast (MCF-7) carcinoma cell lines has been screened. Also, the biopesticidal effect of these compounds against spodoptera littoralis has been examined. Data showed that, the tested [Hg(H2L)(L)] complex (3) possesses the most anticancer efficacy against both HepG2 and MCF-7 cells, with half inhibitory concentration (IC50) = 5.78 ± 0.029, 11.24 ± 0.58 μg/mL, respectively also, this complex considered as good an insecticide with the concentration lethal to 50 percent of test organisms (LC50) = 27585.45 ppm after 72 h. The insecticide and tumor inhibition properties were compared with the theoretical molecular docking findings with the specification of the active species in the designated proteins.

Structure of N-acetoxy-N-benzyloxyurea

The crystal structure of N-acetoxy-N-benzyloxyurea has been studied by single crystal X-ray diffraction study. It has demonstrated that this compound is a typical anomeric amide. ON(1)O nitrogen atom has a pyramidal configuration; the sum of the bond angles centered on N(1) atom is 335.20 and this atom is sp3 hybridized. The N(2) nitrogen atom of the carbamoyl moiety (H2NC=O) has planar configuration. The N–OAc bond is somewhat elongated and the N–OBn bond is shortened due to the action of nO(Bn)*N–OAc anomeric effect. In the molecule of N-acetoxy-N-benzyloxyurea, the N–C amide bonds are nonequivalent, and the (AcO)(BnO)N–C(O) bond is longer that the H2N–C(O) bond. Evidently, that this difference in bond lengths is caused by the stronger conjugation between lone pair (Lp) of the N(2) atom and the C=O carbonyl compared to conjugation between the lone pair of N(1) atom and the C=O carbonyl. The overall analysis of the structural parameters on all known N-acyloxy-N-alkoxyureas had been done. In addition, the structural parameters of N-acetoxy-N-benzyloxyurea have been compared with the same structural parameters of N-benzyloxyurea and N-benzyloxy-N-methoxyurea.

Structural, spectroscopic, fluorescent, and computational studies of binuclear copper (II) and zinc (II) complexes with an asymmetric salamo‐type ligand

Salamo‐type ligand H2L was designed and synthesized and reacted with Cu (II) and Zn (II) acetate, respectively, to obtain two binuclear Cu (II) and Zn (II) complexes: [Cu2(L)2]·2CH3OH (1) and [Zn2(L)2] (2) having the same coordination number but distinct geometries. Complex 1 is a Cu (II) complex containing two crystalline ethanol molecules, where two Cu (II) atoms are surrounded by two utterly deprotonated (L)2− parts, forming slightly twisted tetragonal pyramidal configurations of pentacoordinate. In complex 2, two utterly deprotonated (L)2− parts surround two Zn (II) atoms, forming pentadentate twisted triangular bipyramidal configurations. The complexes were elucidated via IR analyses and ultraviolet spectroscopy. Using DFT theoretical calculation, MEPs, IRI, and Hirshfeld surface analysis to investigate further the molecular interactions and reaction sites. Ultimately, the fluorescence characteristics of H2L and its complexes 1 and 2 were discussed.

Surface Orthogonal Patterning and Bidirectional Self-Assembly of Nanoparticles Tethered by V-Shaped Diblock Copolymers.

We investigated the surface orthogonal patterning and bidirectional self-assembly of binary hairy nanoparticles (NPs) constructed by uniformly tethering a single NP with multiple V-shaped AB diblock copolymers using Brownian dynamics simulations in a poor solvent. At low concentration, the chain collapse and microphase separation of binary polymer brushes can lead to the patterning of the NP surface into A- and B-type orthogonal patches with various numbers of domains (valency), n = 1-6, that adopt spherical, linear, triangular, tetrahedral, square pyramidal, and pentagonal pyramidal configurations. There is a linear relationship between the valency and the average ratio of NP diameter to the polymers' unperturbed root-mean-square end-to-end distance for the corresponding valency. The linear slope depends on the grafting density and is independent of the interaction parameters between polymers. At high concentration, the orthogonal patch NPs serve as building blocks and exhibit directional attractions by overlapping the same type of domains, resulting in self-assembly into a series of fascinating architectures depending on the valency and polymer length. Notably, the 2-valent orthogonal patch NPs have the bidirectional bonding ability to form the two-dimensional (2D) square NP arrays by two distinct pathways. Simultaneously patching A and B blocks enables the one-step formation of 2D square arrays via bidirectional growth, whereas step-by-step patching causes the directional formation of 1D chains followed by 2D square arrays. Moreover, the gap between NPs in the 2D square arrays is related to the polymer length but independent of the NP diameter. These 2D square NP arrays are of significant value in practical applications such as integrated circuit manufacturing and nanotechnology.

Rational design of precious tetrametallic single-cluster catalysts for electrocatalytic nitrate reduction reaction

Single cluster catalysts (SCCs) with high metal loading can exhibit extraordinary catalytic activity in electrocatalytic reactions, but the rational design of active sites remains a challenge. Herein, we proposed a series of SCCs with pyramid-shaped precious tetrametallic clusters anchored on g-CN monolayer (M4/g-CN) as efficient catalysts for the electrochemical reduction of nitrate to ammonia (NO3RR). By means of first-principle computations, the stability, catalytic mechanism and activity, as well as selectivity of these SCCs are systematically investigated. The calculation results show that most SCCs (Ru4/g-CN, Rh4/g-CN, Pd4/g-CN, Os4/g-CN, Ir4/g-CN, Pt4/g-CN) are thermodynamically stable due to the strong binding energy and significant charge transfer behavior between tetrametallic clusters and g-CN support. More important, the volcano curve between limiting potentials and adsorption free energy of NO3‾ can be established, in which Ir4/g-CN can exhibit optimal NO3RR activity due to its location of volcano top. Further analysis of electronic structures reveals that the special pyramid configuration can significantly promote the enrichment of charge on active site and elevate its d-band center, and thus facilitates the NO3RR. This finding pours new vigor into the development of the SCCs family.

Optimization, guidance, and control of low-thrust transfers from the Lunar Gateway to low lunar orbit

The Lunar Gateway will represent a primary space system useful for the Artemis program, Earth–Moon transportation, and deep space exploration. It is expected to serve as a staging location and logistic outpost on the way to the lunar surface. This study focuses on low-thrust transfer dynamics, from the Near-Rectilinear Halo Orbit traveled by Gateway to a specified Low-altitude Lunar Orbit (LLO). More specifically, this research addresses two closely-related problems: (i) determination of the minimum-time low-thrust trajectory and (ii) design, implementation, and testing of a guidance and control architecture, for a space vehicle that travels from Gateway to LLO. Orbit dynamics is described in terms of modified equinoctial elements, with the inclusion of all the relevant perturbations, in the context of a high-fidelity multibody ephemeris model. The minimum-time trajectory from Gateway to a specified lunar orbit is detected through an indirect heuristic approach, which uses the analytical conditions arising in optimal control theory in conjunction with a heuristic technique. However, future missions will pursue a growing level of autonomy, and this circumstance implies the mandatory design and implementation of an efficient feedback guidance scheme, capable of compensating for nonnominal flight conditions. This research proposes nonlinear orbit control as a viable and effective option for autonomous explicit guidance of low-thrust transfers from Gateway to LLO. This approach allows defining a feedback law that enjoys quasi-global stability properties without requiring any offline reference trajectory. The overall spacecraft dynamics is modeled and simulated, including attitude control and actuation. The latter is demanded to an array of reaction wheels, arranged in a pyramidal configuration. Guidance, attitude control, and actuation are implemented in an iterative scheme. Monte Carlo simulations demonstrate that the guidance and control architecture at hand is effective in nonnominal flight conditions, i.e. with random starting point from Gateway as well as in case of temporary unavailability of the propulsion system. The numerical results also point out that only a modest propellant penalty is associated with the use of feedback guidance and control in comparison to the minimum-time optimal trajectory.

Structure and Optical Properties of Sn-Based Halide Perovskites (C10H18N2)SnX4 (X = Cl, Br, I).

Low-dimensional tin-based halide perovskites are considered as eco-friendly substitutions of the iconic lead-based perovskites to host the potential as optoelectronic materials. However, a fundamental understanding of the structure-property relationship of these Sn(II)-based hybrids is still inadequate due to the limited members of this material family. To our knowledge, there is still lack of reports on a series of Sn(II)-based halide perovskites with the same organic cation but covering chloride, bromide, and iodide. In this work, three new halide perovskites TMPDASnX4 (X = Cl, Br, I) (TMPDA = N,N,N',N'-tetramethyl-1,4-phenylenediamine) are successfully synthesized, which provide the ideal paradigm to study the halogen-dependent evolution of the structure and properties of Sn(II)-based hybrid perovskites. Despite sharing the same monoclinic lattice (P21/m space group), it is demonstrated that TMPDASnCl4 adopts a one-dimensional structure composed of a five-coordinated pyramid configuration due to an extremely long Sn···Cl distance, while the typical two-dimensional motif is still maintained in TMPDASnBr4 and TMPDASnI4. The ambient stability is declined in the order from chloride to bromide and then to iodide. TMPDASnCl4 exhibits a broad-band bluish-white-light emission (centered at 515 nm, full width at half-maximum (fwhm) = 193 nm) with the Commission Internationale de l' Elairage (CIE) coordinates as (0.29, 0.34). Further, the correlated color temperature and color-rendering index were determined as 7617 K and 80.5, respectively. Based on the synthesis of new crystals, our work sheds light on the composition-structure-property relationship of hybrid Sn(II)-based halide perovskites.

A computational study on the second-order nonlinear optical response of a new unsymmetrical oxovanadium complex

A new unsymmetrical N2O2 Schiff base oxovanadium (IV) complex, VOLPy, was synthesized with excellent yield and characterized using conventional methods. The crystal structure of the VOLPy complex was determined through X-ray diffraction, revealing a distorted square pyramidal coordination configuration around the central vanadium ion. The solid-state structure is stabilized by various non-covalent short contacts, generating complex 3D supramolecular network. The electrochemical properties of the VOLPy complex were investigated in different media, demonstrating diffusion-controlled reversible or quasi-reversible processes within the potential range of 200–1000 mV, involving a single electron VV/VIV reduction. The diffusion coefficients were calculated using Levich plots Ilim = f(ω1/2). Using quantum calculations at the CAM-B3LYP level with a 6-311G**/LanL2DZ basis set, we systematically assessed various structural parameters, electronic properties, linear and nonlinear optical responses at static and dynamic regimes for oxovanadium complexes, V(V)OL and V(IV)OL, in both gaseous and solvent environments. The results reveal a robust alignment between quantum calculations and experimental data, with only minor deviations. This study anticipates that these specifically designated complexes hold substantial potential as excellent candidates for second-order nonlinear optical (NLO) materials.

High Performance Organic Solar Cells Prepared with Bi‐Triangular Pyramidal Organic Phosphonium Interface Material

AbstractNowadays, amine containing electrode interface material destroy the non‐fullerene acceptor becomes a hard nut to crack for organic solar cells. Developing water‐soluble interface material which is no chemical reaction with non‐fullerene acceptor is an important research theme. Here, we report two bi‐triangular pyramidal electronic configuration organic‐phosphonium bromides as non‐amine cathode interfacial layer for fabricating high‐efficiency stable organic solar cells. The power conversion efficiency (PCE) of inverted device structure with PBDB‐T/ITIC as active layer is up to 11.58 % which is great larger than control device PCE (9.35 %). Same device structure with PM6/Y6 as active layer, the PCE is up to 15.26 % and also is dramatically higher than the referred device PCE 14.36 %. Meanwhile, the devices show greatly improved stability by organic‐phosphonium bromide interlayer.

Double pyramidal central configurations of Newtonian ([formula omitted]+2)-body problem

For double pyramidal central configurations of the Newtonian (N+2)-body problem where N point particles are positioned at the vertices of a regular N-polygon, and the (N+1)-th and (N+2)-th point-particles are positioned the opposite sides of the plane containing the polygon, and the two point particles are located on a line, which is perpendicular to the regular N-polygon, we obtain some properties of the positions, masses and values of N of these N+2 point-particles

Triangular pyramidal configuration of three treads for ring removal.

Triangular pyramidal configuration of three treads for ring removal.

Design and synthesis of triphenylphosphine-based donor-π-acceptor fluorophores with strong aggregation-induced emission and enantiomer-paired flower-like stacking

Triphenylphosphine (TPP) shows stereo pyramidal configuration and has been considered as a poor electron-donor and fluorophore. Here, seven TPP-based compounds (o-TPPs 3a–3e and p-TPPs 3f/g) introducing simple non-aromatic electron-withdrawing (EW) groups at the ortho- and para-position of P atom have been synthesized to understand the inherent optical properties of TPP. All TPPs show aggregation-induced emission (AIE): non-emissive in solutions but emissive upon aggregation. Unexpectedly, lower conjugative o-TPPs possess much higher fluorescence quantum yields (43 and 65 %) than those (1 and 29 %) of their corresponding position isomers, p-TPPs; these achiral pyramidal TPPs in crystals exist as racemic M- and P-enantiomers, with all o-TPPs showing unique MP-paired flower-like arrangements; and the pyramidal TPP moiety could form an excellent electron delocalization system via through-space conjugation. This work proves that TPP could act as an excellent electron-donor and AIEgen by reasonable design, opens a new window to the application of pyramidal TPPs or other pyramidal compounds and affords a new strategy to design strong AIE fluorophores.

Oxidation of Aqueous Phosphorous Acid Electrolyte in Contact with Pt Studied by X-ray Photoemission Spectroscopy.

The oxidation of the aqueous H3PO3 in contact with Pt was investigated for a fundamental understanding of the Pt/aqueous H3PO3 interaction with the goal of providing a comprehensive basis for the further optimization of high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs). Ion-exchange chromatography (IEC) experiments suggested that in ambient conditions, Pt catalyzes H3PO3 oxidation to H3PO4 with H2O. X-ray photoelectron spectroscopy (XPS) on different substrates, including Au and Pt, previously treated in H3PO3 solutions was conducted to determine the catalytic abilities of selected metals toward H3PO3 oxidation. In situ ambient pressure hard X-ray photoelectron spectroscopy (AP-HAXPES) combined with the "dip-and-pull" method was performed to investigate the state of H3PO3 at the Pt|H3PO3 interface and in the bulk solution. It was shown that whereas H3PO3 remains stable in the bulk solution, the catalyzed oxidation of H3PO3 by H2O to H3PO4 accompanied by H2 generation occurs in contact with the Pt surface. This catalytic process likely involves H3PO3 adsorption at the Pt surface in a highly reactive pyramidal tautomeric configuration.

Experimental analysis of one and two-stage thermoelectric heat pumps to enhance the performance of a thermal energy storage

This experimental study demonstrates the possibility to enhance the performance of a low-temperature thermal energy storage system (∼160 °C) based on airflow heating using electrical heaters by including thermoelectric technology. An improvement of the 17 % on COP is reached by using an optimized thermoelectric heat pump system to preheat the airflow, consisting of three one-stage and three pyramidal two-stage thermoelectric heat pumps sequentially installed along the airflow that is heating.This research experimentally analyses and compares the COP of three different configurations of thermoelectric heat pumps: one-stage, square two-stage, and pyramidal two-stage thermoelectric heat pumps. The experimental study aims to characterize the operation of each configuration for heating an airflow of 16.5 m³/h at 25 °C as ambient temperature. To that purpose, the airflow inlet temperature, voltage supply, and voltage ratio between stages have been modified.The experimental results show that for 25 °C as inlet temperature the one-stage thermoelectric heat pump has the best performance with a maximum generated heat of 78 W. Whereas, a two-stage thermoelectric heat pump is required when the inlet temperature increases. At 40 °C as inlet temperature, the square two-stage configuration provides the best performance with a voltage ratio of 2, which reaches a COP of 3.29 generating only 20 W of heat. However, the pyramidal two-stage configuration is able to achieve the maximum heat outputs with a voltage ratio of 1, generating 172; 161; 149 and 138 W, with corresponding COP values of 1.17; 1.16; 1.14 and 1.11 for inlet temperatures of 25; 40; 55 and 70 °C. This configuration is the one that achieves the greatest COP values with high inlet temperatures.

Design and analysis of a nanosatellite attitude control system using processor-in-the-loop approach

This paper presents an approach for the design and analysis of an attitude control system dedicated to a 3U nanosatellite using a low-cost, safe, and reliable processor-in-the-loop system for the rapid prototyping of the final product. It mainly concerns the selection between the two standard configurations of the four reaction wheels, namely the pyramid and tetrahedron configurations. The analysis was carried out by considering the presence of the mechanical uncertainties of the reaction wheels, estimated at 20% of the torque generated, and the environmental disturbances such as magnetic and gravity disturbances, solar pressure, and aerodynamic forces. It also investigates how the regulation is affected by placing the reaction wheels at or outside the spacecraft’s center of gravity. From the results obtained, it turns out that the satellite can be regulated very well regardless of the location of the reaction wheels in the satellite. When placing the actuators outside the center of gravity, a greater effort is required from the reaction wheels to change the satellite attitude, which will consume more electrical energy and wear out the wheels quickly. The torque allocation is used to distribute the forces on the four reaction wheels by means of an optimization adapted to each configuration. The analysis of degraded operation when one or two wheels fail is also studied in detail for the two mechanical configurations discussed.

Synthesis, X-ray Structure and Hirshfeld Surface Analysis of Zn(II) and Cd(II) Complexes with s-Triazine Hydrazone Ligand

The two group IIB complexes [Cd(DMPT)Cl2] (6) and [Zn(DMPT)Cl2] (7) of the tridentate ligand (DMPT), 2,4-bis(morpholin-4-yl)-6-[(E)-2-[1-(pyridin-2-yl) ethylidene]hydrazin-1-yl]-1,3,5-triazine were synthesized, and their structural aspects were elucidated with the aid of X-ray crystallography. Both complexes crystallized in the monoclinic crystal system, with P21/n as a space group. The unit cell parameters for 6 are a = 14.1563(9) Å, b = 9.4389(6) Å, c = 16.5381(11) Å and β = 91.589(5)° while the respective values for 7 are 11.3735(14), 13.8707(13), 14.9956(16), and 111.646(2)°. The unit cell volume is slightly less (2198.9(4) Å3) in complex 7 compared to complex 6 (2209.0(2) Å3). Both complexes have a penta-coordination environment around the metal ion, where the DMPT ligand acts as a neutral tridentate NNN-chelate via the pyridine, hydrazone, and one of the s-triazine N-atoms. The penta-coordination environment of the Cd(II) in complex 6 is close to a square pyramidal configuration with some distortion. On the other hand, the ZnN3Cl2 coordination environment is highly distorted and located intermediately between the trigonal bipyramidal and square pyramids. Supramolecular structure analysis of 6 with the aid of Hirshfeld calculations indicated the importance of the Cl…H, O…H, and C…H interactions. Their percentages were calculated to be 20.9, 9.1, and 8.7%, respectively. For 7, the Cl…H, O…H, C…H, and N…H contacts are the most important. Their percentages are 20.3, 9.0, 7.0, and 8.4%, respectively. In both complexes, the major intermolecular interaction is the hydrogen–hydrogen interactions which contributed 45.5 and 46.6%, respectively.

Suppression of human lysozyme aggregation by a novel copper-based complex of 3,4-dimethoxycinnamic acid

In this work, a new Cu(II)-based complex as a chemotherapeutic drug agent, formulated as[Cu(DCA)4(H2O)2]⋅4H2O⋅4MeOH, (DCA = 3,4-dimethoxycinnamic acid), namely 1 was successfully synthesized utilizing DCA as a ligand to arrest fibrillation in Human lysozyme. The 1 was thoroughly characterized by single crystal X-ray diffraction (SC-XRD), spectroscopic (UV-Vis and FTIR) techniques, PXRD, and TGA analysis. Its crystal structure reveals a paddle wheel network around central copper metal ions. The Cu(II) metal ions exhibit a distorted square pyramidal configuration. The fluorescence titration studies showed moderate binding interaction of 1 with HuL with Ka of 6.3x105 M−1 at pH-2, 25 °C due to its interaction withAsp53, Tyr63, Val110, and Ala111 as shown by docking and simulation studies. 1suppresses the HuL fibrillation in a concentration-dependent manner, as demonstrated by ThT assay. At 200 µM concentration, it leads to the formation of smaller species of the protein in comparison to the control sample, as suggested by Light Scattering studies. The species formed are less hydrophobic and retain their native α-helix structure compared to the control samples, which are hydrophobic and form β-sheet rich amyloids as shown by ANS hydrophobicity assay and CD spectroscopy, respectively. Furthermore, morphological analysis of the species by AFM has demonstrated that, unlike mature amyloid fibrils in the control sample, HuL forms small-size aggregates in the presence of 1 under similar fibrillation conditions. It can be concluded that 1 effectively suppresses HuL fibrillation due to moderate binding to the protein. Communicated by Ramaswamy H. Sarma

Synthesis, crystal structure, Hirshfeld surface, and DFT studies of a Copper(II) complex of 5,5′-dimethyl-2,2′-bipyridine and 1,2,2-trimethylcyclopentane-1,3-dicarboxylic acid

A new metal-organic hybrid complex [Cu(5,5′-dmbipy) (D-cam) (H2O)]n (1), (5,5′-dmbipy = 5,5′-dimethyl-2,2′-bipyridine, D-cam = D-camphoric acid anion) was hydrothermally synthesized. This complex was characterized by FTIR spectroscopy, TGA, and single-crystal X-ray diffraction. Crystallographic studies show that the title complex 1 crystallizes in an orthorhombic system with a P212121 space group with a = 06.9518(05) Ǻ, b = 13.5516(13) Ǻ, c = 22.6380(02)Ǻ; V = 2132.7(3) Ǻ3. The title CuII complex adopts a square pyramidal configuration. DFT study and Hirshfeld topology analysis of complex 1 was also done. The crystal achieves its three-dimensional structure and stability through polymeric chains having helical motifs of arrangement in between moieties and interconnected through hydrogen bonding interactions between the apical water molecule and non-coordinated oxygen atoms of the D-cam2- ligands. TGA, DFT calculations and Hirshfeld topology analysis revealed that the title complex 1 was stable.