Crystals Of Complex Research Articles

Beyond Fundamental Building Blocks: Plasticity in Structurally Complex Crystals.

Intermetallics, which encompass a wide range of compounds, often exhibit similar or closely related crystal structures, resulting in various intermetallic systems with structurally derivative phases. This study examines the hypothesis that deformation behavior can be transferred from fundamental building blocks to structurally related phases using the binary samarium-cobalt system. SmCo2 and SmCo5 are investigated as fundamental building blocks and compared them to the structurally related SmCo3 and Sm2Co17 phases. Nanoindentation and micropillar compression tests are performed to characterize the primary slip systems, complemented by generalized stacking fault energy (GSFE) calculations via atomic-scale modeling. The results show that while elastic properties of the structurally complex phases follow a rule of mixtures, their plastic deformation mechanisms are more intricate, influenced by the stacking and bonding nature within the crystal's building blocks. These findings underscore the importance of local bonding environments in predicting the mechanical behavior of structurally related intermetallics, providing crucial insights for the development of high-performance intermetallicmaterials.

Petrology and geochemistry of the Suhum Basin granitoid complex, Ghana: Implications for crustal growth during the Rhyacian orogeny of the West African Craton

The Suhum Basin granitoid complex is an important granitoid complex of the Birimian terrane of Ghana for unravelling the crustal growth and evolution of the West African Craton (WAC) during the Rhyacian Eburnean orogeny. Almost the entire Suhum Basin is occupied by an extensive granitoid complex, which contains useful information for constraining debatable plate tectonic issues, especially during the Archean-Paleoproterozoic transition period. We present petrography, whole-rock geochemistry, and mineral chemistry data of biotite, amphibole, and plagioclase to constrain the temperature-pressure conditions of emplacement, petrogenesis, tectonic setting, the evolution of the granitoids complex of the Suhum Basin, and its implications for the crustal growth and evolution of the WAC. Four lithological types; granite gneiss, migmatites, leucogranites, and mafic enclaves, characterise the granitoid complex of the Suhum Basin. Biotites from the granitoid complex have an annite-siderophyllite composition, and that, coupled with their calc-alkaline and I-type signatures, indicates crystallisation of the granitoid complex of the Suhum Basin under oxidised conditions. The medium-to high-K character of the rocks, together with the calc-alkaline nature, may be a reflection of the generation of magma in regions where the mantle wedge might have interacted with enriched fluids from the underlying plate during dehydration. The enrichment of LILE and LREE relative to HREE and HFSE and the negative Eu, Nb-Ta, and Ti anomalies of the granitoids complex may indicate derivation from enriched magma sources with varying degrees of fractionation in an arc environment. Amphibole-plagioclase thermobarometry indicates that the granitoid complex formed at P-T conditions of 600–712 °C and 5.2–7.2 kbar, signifying a deeper depth (19–27 km) of emplacement. The overall geochemical data suggest that the rocks formed during a single orogenic event related to a volcanic arc environment where subduction zone components played a role in the generation of their parental magmas. This finding is therefore consistent with the onset of “modern-style” subduction-related processes during the Archean-Paleoproterozoic transitional period.

A High-Dimensional Spin-Qudit Candidate of Gd(III) Center Complex Crystal with Addressable Transitions

A High-Dimensional Spin-Qudit Candidate of Gd(III) Center Complex Crystal with Addressable Transitions

Nickel(II) and Copper(II) Dicyanoargentate Complexes with Ethylenediamine and 4,4´-Bipyridyl Ligands

The reactions of an aqueous solution of potassium dicyanoargentate with a mixture of nickel(II) or copper(II) chloride and ethylenediamine or 4,4´-bipyridyl in ethanol afford coordination polymers [Ni(En)2(Ag(CN)2)][Ag(CN)2] (I), [Cu(En)2(Ag(CN)2)][Ag(CN)2] (II), and [Cu(4,4´-Bipy)2(Ag(CN)2)2] (III) characterized by XRD (CIF files CCDC nos. 2225984 (I), 2214320 (II), and 2229270 (III)) and IR spectroscopy. According to the XRD data, the crystals of complexes I and II are formed by 1D chains {··NC– Ag–CN–M(En)2··}n (M = Ni (I), Cu (II)) linked with each other by the dicyanoargentate anions via argentophilic contacts (Ag···Ag 3.288(8) Å (I), 3.1616(14) Å (II)). The crystal of compound III consists of independent interpenetrating 3D networks built of polymer layers {Cu[Ag(CN)2]2}n bound to each other by the 4,4´-bipyridyl molecules. The bipyridyl linkers connect the Cu centers with the Ag centers of the [Ag(CN)2]– anions thus providing the tridentate coordination of the silver atoms. No Ag···Ag interactions are observed in the crystal of complex III.

Solvation modeling and optical properties of CdSO4-Doped L-Valine crystals

The utilization of computational solvation models for crystals proves effective in determining the amalgamation of molecular structures within the crystal medium, offering valuable insights into optimized crystal properties. This study focuses on identifying the arrangement of molecular strips within the crystal, crucial for recognizing active planes and the presence of non-linear optical (NLO) properties. To delve into the crystal's intricacies, a computational model was developed, and conformational analysis was conducted to ensure NLO property. The synthesis of the CdSO4-doped L-Valine metallo-organic complex crystal was achieved through the melt-freezing technique. The computational model was constructed to elucidate the formation of sub-planes within a confirmed orthorhombic crystal lattice. Mapping the molecular charge distribution with the dispersion of charge gradient facilitated the identification of chemical potential inhibition and its equipotential nodal domains. The estimation of electron density potential over critical points of the core carbons provided further insights. Chemical dynamics on the electron content of molecules for NLO properties were investigated by screening control parameters. The inelastic scattering ability of heteronuclear bonds for enhancing boosting potential was observed. Interactive frontier orbitals of degenerate energy states were illustrated, and the chemical potential of molecular zones was analyzed in-depth.

Revealing protein structures: crystallization of protein-ligand complexes - co-crystallization and crystalsoaking.

Protein crystallogenesis represents a key step in X-ray crystallography studies that employ co-crystallization and ligand soaking for investigating ligand binding to proteins. Co-crystallization is a method that enables the precise determination of binding positions, although it necessitates a significant degree of optimization. The utilization of microseeding can facilitate a reduction in sample requirements and accelerate the co-crystallization process. Ligand soaking is the preferred method due to its simplicity; however, it requires careful control of soaking conditions to ensure the successful integration of the ligands. This research protocol details the procedures for co-crystallization and soaking to achieve protein-ligand complex formation, which is essential for advancing drug discovery. Additionally, a simple protocol for demonstrating soaking for educational purposes is described.

A dual-channel fluorescent probe based on salamo-Cu(II) complex for sensitive detection of S2- in river and tap water

A new double-salamo-type tetranuclear copper complex [Cu4(L)2](ClO4)2.2CH2Cl2 was designed and prepared, in which the metal atoms in the complex crystals have two different coordination systems, forming a symmetric structure as a whole. As a complex probe molecule, the addition of S2- in solution can achieve a red shift in the fluorescence spectrum, revealing bright green fluorescence, colorimetric and fluorescent dual-channel specific recognition ability and excellent anti-interference ability. The probe can be used to detect S2- by adding acidic and alkaline solutions to adjust the pH of the system for several cycles, which is suitable for ion recognition in most organisms and environments under pH conditions. The working mechanism of S2-recognition by Cu–ZTS was determined to be a synergistic action of ESIPT effect and ICT effect by correlation spectroscopy experiments, HR-MS and XPS tests, and this conclusion was subsequently further verified using theoretical calculations. Finally, the probe molecule showed good practical application value, and the portable test strips were prepared to qualitatively detect the ions, and by testing four different water samples, it was shown that the quantitative recognition of S2- could be realized almost without interference in real water samples. It proves that the coordination probe molecule has good prospects for practical application.

Photoluminescent Lanthanide(III) Complexes Based on 2-[((4-Chlorophenyl)amino)methylene]-5,5-dimethylcyclohexane-1,3-dione

Five coordination compounds of the general formula [LnL2(NO3)3]n (Ln3+ = Eu (I), Sm (II), Tb(III), Dy (IV), and Gd (V)) are synthesized from 2-[((4-chlorophenyl)amino)methylene]-5,5-dimethylcyclohexane-1,3-dione (L). The crystal structures of the ligand and complex III are determined by X-ray diffraction (XRD) of single crystals (CIF files CCDC nos. 2298715 (L) and 2298716 (III)). Complex III is polymeric due to the bidentate-bridging coordination of the ligand by the oxygen atoms of the cyclohexanedione fragment, and the coordination number of the central atom is ten. According to the phase XRD data, all synthesized polycrystalline compounds are isostructural to the single crystals of complex III. The photoluminescence properties of the ligand and coordination compounds in the polycrystalline state are studied. The energy transfer from the ligand to lanthanide(III) ion is shown to proceed via the “antenna” mechanism in the case of the europium(III), samarium(III), and terbium(III) compounds. Among the series of the complexes, the highest quantum yield is observed for compound I (21.9%), and the sensibilization efficiency of the europium(III) complex is 43.5%.

Crystal structure of bis-(μ2-5-nona-noylquinolin-8-olato)bis-[aqua-dichlorido-indium(III)

Crystallization of 5-nona-noyl-8-hy-droxy-quinoline in the presence of InCl3 in aceto-nitrile yields a dinuclear InIII complex crystallizing in the space group P. In this complex, [In2(C18H22NO2)2Cl4(H2O)2], each indium ion is sixfold coordinated by two chloride ions, one water mol-ecule and two 8-quinolino-late ions. The crystal of the title complex is composed of two-dimensional supra-molecular aggregates, resulting from the linkage of the Owater-H⋯O=C and Owater-H⋯Cl hydrogen bonds as well as bifurcated Carene-H⋯Cl contacts.

DNA/BSA Binding and Antimicrobial Properties of Biguanide-Cu(II) Complexes.

The biguanide Cu(II) complexes [Cu(L1-4)2](ClO4)2 were synthesized and spectroscopic/analytical techniques were used to clarify their structures. Single crystals of complex [Cu(L4)2](ClO4)2 was obtained and its definite structure was determined by single crystal X-ray diffraction study. The complexes [Cu(L1-4)2](ClO4)2 were screened for their FSds-DNA interactions by using UV-Vis absorption and fluorescence spectroscopies. The complexes [Cu(L2)2](ClO4)2 and [Cu(L3)2](ClO4)2 were shown to exhibit higher affinity for binding DNA. Examining the EB-DNA interaction, it is believed that the complexes interact with DNA through a groove binding mechanism. The interaction of complexes with BSA were observed through the quenching of the fluorescence emission. Complexes [Cu(L2)2](ClO4)2 and [Cu(L3)2](ClO4)2 show moderate binding affinity to BSA through a static mode. Additionally, the Cu(II) complexes were screened for their antibacterial activities against various bacterial strains. Complexes showed potential antimicrobial activity against Salmonella typhimurium, Bacillus cereus, Salmonella typhimurium and S. aureus.

Investigating the Mechanism of Triboluminescence: Insights from Structural and Electrostatic Characterization of Copper Thiocyanate Complexes.

Triboluminescence is a phenomenon in which light is generated through mechanical stress; it has emerging applications in stress-sensing devices. Although the prevailing mechanistic model indicates that light emits from charge separation and recombination in fracture planes arising from polar structures, its application in designing triboluminescent materials remains limited owing to numerous exceptions. This study provides insights into the essential requirements for triboluminescence by investigating the structural and electrostatic properties of fractured crystals of copper thiocyanate complexes. The examined fracture plane indicated that charge pairs (which are essential for light emission) form when intermolecular interactions are disrupted during fracturing. On the basis of the nature of these charges, we successfully suppressed triboluminescence by inhibiting the formation of intermolecular interactions disrupted in the examined complexes. Furthermore, we induced its re-emergence by creating an alternative fracture plane through controlled manipulation of the molecular network. This demonstrative deactivation and reactivation of triboluminescence underscores the critical role of intermolecular disruption in generating charge pairs, a prerequisite for triboluminescence.

Experimental and DFT perspectives: exploring spectral, linear and nonlinear optical properties of p-nitrophenol complex crystal for NLO applications

Experimental and DFT perspectives: exploring spectral, linear and nonlinear optical properties of p-nitrophenol complex crystal for NLO applications

Shaped ionic wood for enhanced phase change performance

Wood with a porous structure is the best carrier for phase change energy storage materials, which can effectively prevent material leakage during thermal cycling and ensure its shaping effect. In this work, natural poplar wood was treated with delignification and then oxidized by TEMPO as a thermal energy storage matrix. Then, it was immersed in a solution of ethanol as the solvent, polyethylene glycol (PEG) and calcium chloride as the solutes, obtaining phase change energy storage ionic wood (DTW-PCMs). The results showed that the phase change energy storage material PEG-CaCl2 was successfully impregnated into the pore structure of wood; calcium chloride was effectively combined with –COOH in TEMPO oxidized wood for intermediate bonds and formed white complex crystals with PEG2000. The maximum absorption rate and differential scanning calorimetry (DSC) test results showed that TEMPO-oxidized poplar had a maximum absorption rate of 95.26% for PEG2000-CaCl2. Additionally, TEMPO-oxidized poplar exhibited good phase transition performance and suitable phase change temperature. The latent heat of phase transition was 86.96 J/g. Thus, the novel DTW-PCMs displayed a high potential application in the field of thermal energy storage and temperature regulation.

Effects of particle size on the crystallization kinetics characterization in CaO–SiO2‐based glass, Part 2: In complex crystallization processes with two or more crystal phases

AbstractBased on the Matusita–Sakka equation and the exothermic peaks in the differential thermal analysis (DTA) curves, in silicate glasses with complex crystallization processes containing the precipitation of two or more crystal phases, the effects of particle sizes on the calculations of crystal growth dimensionality and activation energy of crystal growth have been studied in depth. In crystallization processes with two or more crystal phases but one exothermic peak, 0.3 mm is considered as the boundary between the fine and the coarse particles in this type of glass. For glass samples with a particle size less than 0.3 mm, the crystal growth dimensionality is a three‐dimensional mechanism, and EG increases slightly with decreasing particle size. For glass samples with a particle size greater than 0.3 mm, the crystal growth dimensionality is a two‐dimensional mechanism, and EG increases with decreasing particle size. The EG for the fine‐particle starting material is much lower than that of the coarse‐particle starting material. In crystallization processes with two or more crystal phases and two exothermic peaks, 0.104 mm is considered as the boundary between the fine and the coarse particles in this type of glass raw material. For the first peak, in glass samples with a particle size less than 0.104 mm, the crystal growth mechanism is mainly one‐dimensional growth, and EG increases slightly with decreasing particle size. And for glass samples with particle size greater than 0.104 mm, the crystal growth mechanism is mainly two‐dimensional growth, and EG decreases with decreasing particle size. For the second peak, the crystal growth mechanism is mainly a three‐dimensional growth, and EG increases with decreasing particle size.

Kinetics study and fragility of (Cu50Zr43Al7)98Y2 bulk metallic glass

Crystallization transformation kinetics and fragility of (Cu50Zr43Al7)98Y2 bulk metallic glass (BMG) were investigated at non-isothermal and isothermal conditions by differential scanning calorimetry. Activation energies for the BMG were calculated for the glass transition, onset crystallization, and crystallization peak using various methods of non-isothermal analysis. Results suggested that atomic rearrangement during glass transition is more complex than crystallization, and growth poses greater challenges than nucleation. Isothermal analysis conducted in the supercooled liquid region provides evidence of crystallization being controlled by diffusion, with a calculated mean Avrami exponent of 2.2. Additionally, the findings of fragility studies and kinetic studies demonstrated a strong correlation with the glass-forming ability (GFA), thereby validating the high GFA of the BMG analyzed in this study. Thus, this research results provide a detailed understanding of the complex crystallization kinetics, thermal behavior, and GFA of (Cu50Zr43Al7)98Y2 BMG, emphasizing its potential in materials science applications.

Effective optimization of atomic decoration in giant and superstructurally ordered crystals with machine learning.

Crystals with complicated geometry are often observed with mixed chemical occupancy among Wyckoff sites, presenting a unique challenge for accurate atomic modeling. Similar systems possessing exact occupancy on all the sites can exhibit superstructural ordering, dramatically inflating the unit cell size. In this work, a crystal graph convolutional neural network (CGCNN) is used to predict optimal atomic decorations on fixed crystalline geometries. This is achieved with a site permutation search (SPS) optimization algorithm based on Monte Carlo moves combined with simulated annealing and basin-hopping techniques. Our approach relies on the evidence that, for a given chemical composition, a CGCNN estimates the correct energetic ordering of different atomic decorations, as predicted by electronic structure calculations. This provides a suitable energy landscape that can be optimized according to site occupation, allowing the prediction of chemical decoration in crystals exhibiting mixed or disordered occupancy, or superstructural ordering. Verification of the procedure is carried out on several known compounds, including the superstructurally ordered clathrate compound Rb8Ga27Sb16 and vacancy-ordered perovskite Cs2SnI6, neither of which was previously seen during the neural network training. In addition, the critical temperature of an order-disorder phase transition in solid solution CuZn is probed with our SPS routines by sampling site configuration trajectories in the canonical ensemble. This strategy provides an accurate method for determining favorable decoration in complex crystals and analyzing site occupation at unprecedented speed and scale.

Exfoliatable Layered 2D Honeycomb Crystals of Host-guest Complexes Networked by CH-π Hydrogen Bonds.

Studies of graphene show that robust chemical bonds such as covalent bonds with trigonal-planar atoms afford layered atomic 2D crystals possessing unique properties. Although layered molecular crystals are of interest to diversify elements and structures of 2D materials, the structural diversity of molecules as well as weak intermolecular interactions inevitably makes the design to be one-off and individual. We herein report a versatile method to assemble layered molecular crystals. By developing a D3-symmetry host at vertices to form a honeycomb layer, a diverse range of layered 2D host-guest crystals were obtained. Substituents on the host, elements/structures of the guest, the stereochemistry of the host and types of intercalants were diversified, which should allow for 6×32×3×2 combinations for structural diversification.

Real space method for HAADF image simulation

A new real space HAADF simulation method was described in detail and a Real Space- STEM software was developed based on the new simulation method. The algorithm of the real space method can quickly calculate and simulate the microstructure images of complex crystals. The Real Space-STEM software developed in this paper has the functions of HRTEM and HAADF image simulation based on the real space method. By using this software to simulate high-resolution images of representative crystal materials from each crystal system, the HAADF images are both accurate and efficient. The effect of STEM parameters on HAADF imaging has been discussed using simulation results.

Podophyllotoxin derivatives-tubulin complex reveals a potential binding site of tubulin polymerization inhibitors in α-tubulin adjacent to colchicine site

The colchicine site of β-tubulin has been proven to be essential binding sites of microtubule polymerization inhibitors. Recent studies implied that GTP pocket of α-tubulin adjacent to colchicine sites is a potential binding site for developing tubulin polymerization inhibitors. However, the structural basis for which type of structural fragments was more beneficial for enhancing the affinity of α-tubulin is still unclear. Here, podophyllotoxin derivatives-tubulin complex crystals indicated that heterocyclic with the highly electronegative and small steric hindrance was conducive to change configuration and enhance the affinity of the residues in GTP pocket of α-tubulin. Triazole with lone-pairs electrons and small steric hindrance exhibited the strongest affinity for enhancing affinity of podophyllotoxin derivatives by forming two hydrogen bonds with αT5 Ser178. Pyrimidine with the secondary strong affinity could bind Asn101 to make the αH7 configuration deflection, which reduces the stability of tubulin result in its depolymerization. Conversely, 4β-quinoline-podophyllotoxin with the weakest affinity did not interact with α-tubulin. The molecular dynamics simulation and protein thermal shift results showed that 4β-triazole-podophyllotoxin-tubulin was the most stable mainly due to two hydrogen bonds and the higher van der Waals force. This work provided a structural basis of the potential binding sites for extending the α/β-tubulin dual-binding sites inhibitors design strategy.

Evaluation of Ammonium Nitrate(V) Morphology and Porosity Obtained by SEM and Tomography Imaging.

This paper presents an evaluation of the morphology of fertilizer-grade and prill-grade ammonium nitrate(V). All samples were analyzed using X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and tomography techniques. The XRD results revealed that despite various provenances, all samples exhibited similar Pmmm symmetry and diffraction patterns. SEM images indicated that prill ammonium nitrate(V) showed a more complex external and internal crystal structure than fertilizer-grade counterparts. Furthermore, tomography analysis revealed that each prill ammonium nitrate(V) sample demonstrated distinct porosity characteristics, including varying pore sizes and distribution patterns. Both methods confirmed that fertilizer-grade ammonium nitrate(V) in the cross-section had a pumice structure, and porous prill ammonium nitrate(V) had a rather complex structure, with a central cavity observed only in the case of Sample 4. The appearance of a central cavity can be explained by the different conditions or manufacturing processes of porous prill ammonium nitrate(V). Moreover, the fertilizer-type ammonium nitrate(V) exhibited the lowest surface-to-volume ratio of ca. 21% compared to the porous-type ammonium nitrate(V). This, together with the lowest surface area of ca. 116 mm2, confirmed the lowest absorption capacity of the fertilizer-grade ammonium nitrate(V) disclosed by the ammonium nitrate(V) producer.