Monoclinic Cell Research Articles

Triclinic polymorph of bis[2-methyl-3-(pyridin-2-yl)imidazo[1,5-a]pyridin-2-ium] tetrachloridocadmium(II)

The crystal structure of the title organic–inorganic hybrid salt, (C13H12N3)2[CdCl4], (I), has been reported with four molecules in the asymmetric unit in a monoclinic cell [Vassilyeva et al. (2021). RSC Advances, 11, 7713–7722]. While using two different aldehydes in the oxidative cyclization–condensation involving CH3NH2·HCl to prepare a new monovalent cation with the imidazo[1,5-a]pyridinium skeleton, a new polymorph was obtained for (I) in space group P 1 and a unit cell with approximately half the volume of the monoclinic form. The structural configurations of the two crystallographically non-equivalent organic cations as well as the geometry of the moderately distorted tetrahedral CdCl4 2– dianion show minor changes. In the crystal, identically stacked cations and tetrachlorocadmate anions form separate columns parallel to the a axis. The loose packing of the anions leads to a minimal separation of approximately 9.53 Å between the metal atoms in the triclinic form versus 7.51 Å in the monoclinic one, indicating that the latter is packed slightly more densely. The two forms also differ by aromatic stacking motifs. Similar to the monoclinic polymorph, the triclinic one excited at 364 nm shows an intense unsymmetrical photoluminescent band with maximum at 403 nm and a full width at half maximum of 51 nm in the solid state.

An efficient way to grow large size single crystal of imidazole by modified Czochralski technique and study of its optical and mechanical properties

Large-sized single crystal of imidazole was successfully grown for the first time by cost-effective modified Czochralski technique for lower melting point materials. Its monoclinic crystal system and cell parameters a = 7.7251 Å, b = 5.4450 Å, c = 9.2599 Å, and β = 110.556° were determined through single crystal and powder XRD analysis. Hisrshfeld surface analysis and 2D fingerprint plot of imidazole revealed that H···H, C···H/H···C and H···N/N···H has 49.7 %, 18.7 % and 28.9 % of overall intermolecular interactions present in the crystal. Direct band gap nature, high transmittance and lower absorption cutoff at 236 nm was found in UV–Vis spectroscopy. Thermal studies of the crystal were carried out using TGA and DSC analysis and sharp endothermic peak showed high crystallinity and thermal stability up to its melting point. Fundamental functional groups of the crystals were identified by FTIR technique. Mechanical strength of imidazole single crystal was analyzed by Vickers microhardness at different loads, and it was observed that after 20 g load crystals showed indentation size effect.

Crystal structure, electronic structure and thermal stability of new phosphate Sr2In(PO4)(P2O7)

Searching for new phosphates is of special significance to enrich the basic database of the structure and properties for developing inorganic materials. Here, we present a new phosphate Sr2In(PO4)(P2O7) which crystallizes to a monoclinic cell (S.G. P21/c), with the lattice parameters of a = 6.5832(3) Å, b = 6.8984(3) Å, c = 19.813(1) Å, β=99.562(1)°, V = 887.3(1) Å3, and Z = 2. The three-dimensional frame of this structure is made of InO6, PO4, P2O7, SrO8, and SrO9 units. The co-existence of P2O7 and PO4 was confirmed by IR spectra assignment. The VB maximum and CB minimum of Sr2In(PO4)(P2O7) are dominated by In-s and O-p state, respectively. Combining the calculated electronic structure with measured UV–Vis diffuse reflectance spectrum, this phosphate shows a wide indirect energy band-gap. DTA indicates that its melt point is about 1245 °C. The large band gap and high thermal stability would be catering for the material requirement in futural optical or other functional application fields.

From Cs[C2N3] to Cs3[C6N9] – a thermal and structural investigation

Abstract Cesium dicyanamide Cs[C2N3] (≡ Cs[N(CN)2] or Cs[dca]) was obtained by a metathesis reaction in form of transparent colorless platelets. The results of single-crystal X-ray structure measurements and refinements (C2/c, Z = 8) with the monoclinic cell parameters a = 932.31(8), b = 1274.67(9), c = 824.94(7) pm, β = 110.803(3)° at −70 °C and a = 939.59(7), b = 1281.58(8), c = 827.57(6) pm, β = 110.610(3)° at 20 °C corroborate earlier results for this compound. The Raman and IR spectra of Cs[C2N3] are presented for the first time and the result compares well with those of NaCs2[C2N3]3. The heat-driven cyclotrimerization process of Cs[C2N3] was studied by thermal analyses (DSC) and temperature-dependent X-ray powder diffraction methods. At 370 °C, its trimerization product Cs3[C6N9] is formed, crystallizing in the orthorhombic space group Pbam with the cell parameters a = 3043.0(3), b = 1052.4(1) and c = 415.21(4) pm for Z = 4. The IR spectrum of this cesium tricyanomelaminate (Cs3[C6N9] or Cs3[TCM]) is presented, but a well-resolved Raman spectrum could not be acquired owing to fluorescence phenomena. An overview about the cyclotrimerization reactions of all pseudo-binary alkali-metal dicyanamides (A[C2N3]) to their corresponding tricyanomelaminates (A 3[C6N9]) with A = Li–Cs gives a basis for a discussion of the different thermal and structural characteristics.

Optimizing deposition regimes to fabricate VO2/TiO2/c-Al2O3 thin films for active metasurfaces

Decreasing the scale of vanadium dioxide (VO2) structures is one of the ways to enhance the switching speed of the material. We study the properties of VO2 films of altered thicknesses in the range of 20–170[Formula: see text]nm prepared on c-sapphire substrates with a TiO2 sublayer by pulsed laser deposition (PLD) method. The synthesis regime to design a TiO2 film was preliminarily optimized based on XRD data. XRD patterns reveal an epitaxial growth of the VO2 films with distortion of the monoclinic cell to hexagonal symmetry. The positions of the lattice vibration modes in Raman spectra are similar to those in bulk VO2 when the film thickness is greater than [Formula: see text][Formula: see text]nm. For VO2 films thicker that [Formula: see text][Formula: see text]nm, a lattice strain results in the modes’ positions and intensity change. However, the electrically triggered transition in a [Formula: see text][Formula: see text]nm thick VO2 film reveals forward and reverse switching times as short as 20[Formula: see text]ns and 400[Formula: see text]ns, correspondingly.

Enhancing the optical properties of [P(MMA-co-AN)/ZrO2]TF by doping fluorescein dye, TD-DFT/DMOl3 simulations and COVID-19 main protease docking

Poly methyl methacrylate-co-acrylonitrile [P(MMA-co-AN)]HB hybrid blend was first synthesized by precipitation polymerization and characterized by static light scattering. With a thickness of 200 ± 5 nm, the hybrid nanocomposite of [P(MMA-co-AN)/ZrO2]HNC thin films were fabricated by spin coating method. X-Ray diffraction studies showed a monoclinic cell structure with an average crystalline size of 180 nm for the fabricated films. An improvement in the optical properties were figured out when fluorescein dye was doped in the hybrid nanocomposite. Where the optical energy gap was decreased from 4.31 to 4.025 eV for fluorescein doped hybrid nanocomposite. While a possible energy transfer between ZrO2 and fluorescein was investigated in the laser photoluminescence spectra. DFT-CASTEP simulations were deployed to calculate the theoretical optical properties for the molecules under consideration. The structural and optical simulations of [P(MMA-co-AN)/ZrO2]HNC were found to match the experimental data. Molecular docking studies of [P(MMA-co-AN)/ZrO2]Iso against the main protease of novel corona virus COVID 19 (PDB code 6LU7 Hormone) showed an interesting interaction.

Synthesis, thermal, spectroscopic and dielectric studies of the new borates Ba2M1-xNix(BO3)2 M = Mg, Cd

The aim of this work is to examine the addition of nickel in borate materials with chemical formula Ba2M1-xNix(BO3)2, M = Mg; Cd. The samples have been successfully prepared by solid state reaction at 850 °C. The borates Ba2Cd1-xNix(BO3)2 crystallize in the monoclinic cell with space group C2/m and the others system Ba2Mg1-xNix(BO3)2 exhibits the rhombohedra structure (trigonal system) with space group R-3 m. The infrared spectroscopy confirms the existence of trigonal coordination for the boron ions in the studied systems. The investigation by differential scanning calorimetry (DSC) highlights several thermal phenomena in the borates studied. The dielectric measurement as function of frequency shows the relaxation behavior in the studied materials. The phenomena observed by differential scanning calorimetry are confirmed and interpreted by means of the dielectric study at high temperatures.

Phase Transition‐Promoted Rapid Photomechanical Motions of Single Crystals of a Triene Coordination Polymer

AbstractMolecular crystals with the ability to transform light energy into macroscopic mechanical motions are a promising class of materials with potential applications in actuating and photonic devices. In regard to such materials, coordination polymers that exhibit dynamic photomechanical motion, associated with a phase transition, are unknown. Herein, we report an intriguing photoactive, one‐dimensional ZnII coordination polymer, 1, derived from 1,3,5‐tri‐4‐pyridyl‐1,2‐ethenylbenzene and 3,5‐difluorobenzoate. Single crystals of 1 under UV light irradiation exhibit rapid shrinking and bending, violent bursting‐jumping, splitting, and cracking behavior. Single‐crystal X‐ray diffraction analysis and 1H NMR spectroscopy reveal an unusual photoinduced phase transition involving a single‐crystal‐to‐single‐crystal [2+2] cycloaddition reaction that results in photomechanical responses. Interestingly, crystals of 1, which are triclinic with space group , are transformed into a higher symmetry, monoclinic cell with space group C2/c. This process represents a rare example of symmetry enhancement upon photoirradiation. The photomechanical activity is likely due to the sudden release of stress associated with strained molecular geometries and significant solid‐state molecular movement arising from cleavage and formation of chemical bonds. A composite membrane fabricated from 1 and polyvinyl alcohol (PVA) also displays interesting photomechanical behavior under UV light illumination, indicating the material's potential as a photoactuator.

Phase Transition-Promoted Rapid Photomechanical Motions of Single Crystals of a Triene Coordination Polymer.

Molecular crystals with the ability to transform light energy into macroscopic mechanical motions are a promising class of materials with potential applications in actuating and photonic devices. In regard to such materials, coordination polymers that exhibit dynamic photomechanical motion, associated with a phase transition, are unknown. Herein, we report an intriguing photoactive, one-dimensional ZnII coordination polymer, 1, derived from 1,3,5-tri-4-pyridyl-1,2-ethenylbenzene and 3,5-difluorobenzoate. Single crystals of 1 under UV light irradiation exhibit rapid shrinking and bending, violent bursting-jumping, splitting, and cracking behavior. Single-crystal X-ray diffraction analysis and 1 H NMR spectroscopy reveal an unusual photoinduced phase transition involving a single-crystal-to-single-crystal [2+2] cycloaddition reaction that results in photomechanical responses. Interestingly, crystals of 1, which are triclinic with space group , are transformed into a higher symmetry, monoclinic cell with space group C2/c. This process represents a rare example of symmetry enhancement upon photoirradiation. The photomechanical activity is likely due to the sudden release of stress associated with strained molecular geometries and significant solid-state molecular movement arising from cleavage and formation of chemical bonds. A composite membrane fabricated from 1 and polyvinyl alcohol (PVA) also displays interesting photomechanical behavior under UV light illumination, indicating the material's potential as a photoactuator.

Determination of the supramolecular arrangement of Dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene films fabricated by Physical Vapor Deposition and possible implications for electronic devices

Organic thin films have been used as active layers and are an alternative to inorganic materials in order to improve the performance of electronic devices. Recently, Dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT) became an important compound in organic electronics due to its optical and electrical properties, which are dependent on the supramolecular arrangement. Thus, in this work we determined the supramolecular arrangement of organic thin films of DNTT (DNTT PVD films) fabricated by Physical Vapor Deposition (PVD). Ultraviolet-visible absorption spectra showed the controlled growth of the films within the range from 17 to 120 nm and the formation of aggregates (J- and H-), as the H-aggregate was favored by the thickness. The emission spectra revealed that excimers are responsible for the emission in DNTT PVD films and the increase in solution concentration led to the formation of H-aggregates primarily. The molecular organization of the films, determined by selection rules of Fourier Transform Infrared absorption spectroscopy, suggested that the molecules had a preferential chain-on organization for 120 nm thickness film. Complementary, X-Ray Diffraction data showed that DNTT PVD film was practically monocrystalline with monoclinic cell unit, also determined for the 120 nm thickness film. Atomic Force Microscopy measurements revealed that DNTT film had a homogeneous surface (roughness around 6 nm for the film with 120 nm thickness) with grains of uniform size and geometry. Thus, based on the characteristics of the supramolecular arrangement (especially the molecular organization and increase of H-aggregates with the thickness of DNTT PVD film and the results found in the literature), it was possible to analyze probable implications of chain-on molecular organization and the increase of H-aggregates with the film thickness on the mobility of charge carriers of devices, such as diodes and transistors, in which they are applied.

Metallogels: a novel approach for the nanostructuration of single-chain magnets.

In this study we demonstrate that single-chain magnets (SCMs) can be assembled in gel phase and transferred intact on surface. We take advantage of a family of SCMs based on TbIII ions and nitronyl-nitroxides radicals functionalized with short alkyl chains known to form crystalline supramolecular nanotubes interacting with heptane acting as crystallizing solvent. When the radicals are functionalized with long aliphatic chains a robust gel is formed with similar structural and functional properties respect to its crystalline parent. Indeed, a small-angle X-ray scattering (SAXS) study unambiguously demonstrates that the gel is made of supramolecular nanotubes: the high stability of the gel allows the determination from SAXS data of precise nanotube metrics such as diameter, helical pitch and monoclinic cell of the folded 2D crystal lattice along the tube direction. Additionally, static and dynamic magnetic investigations show the persistence of the SCM behavior in the metallogel. Last, on-surface gelation provides thick films as well as sub-monolayer deposits of supramolecular nanotubes on surface as evidenced by atomic force microscopy (AFM) observations. This paves the road toward magnetic materials and devices made of SCMs profiting of their isolation on surface as individual chains.

INESITE, HUBEITE, RUIZITE, APOPHYLLITE, AND MANGANOAN ILVAITE FROM CAVNIC, EASTERN CARPATHIANS, ROMANIA

The rare minerals, inesite, Ca2Mn2+7Si10O28(OH)2·5H2O, hubeite, Ca2Mn2+Fe3+Si4O12(OH)·2H2O, and ruizite, Ca2Mn3+Si4O11(OH)4·2H2O, were determined, for the first time, by optical and XRD analyses, at Cavnic (Baia Mare Neogene metallogenetic district, Eastern Carpathians, Romania) in a gold-bearing, base metal deposit. Inesite was refined as triclinic, in space group P1 (2), and has the following unit-cell parameters (refined from X-ray powder diffraction data): a = 8.927(7) Å, b = 9.245(8) Å, c = 11.954(9) Å; α = 91.80(2)°, β = 132.60(1)°, γ = 94.37(3)°, V = 719.45(12)Å3. Hubeite was also refined as triclinic, in space group P1, and has as unit-cell parameters: a = 9.960(7) Å, b = 13.870(9) Å, c = 6.562(4) Å, V = 601.19(17) Å3; α = 133.19(5)°, β =101.50(3)°, γ = 66.27(4)°. Ruizite was refined on a monoclinic cell, space group A2 (5) and has the following unit-cell parameters: a = 11.974(9)Å, b = 6.175(5)Å, c = 9.052(7)Å, V = 669.12 (9)Å3; β = 91.34(3)°. Apophyllite, KCa4Si8O20(F,OH)·8H2O, is tetragonal, space group P4/mnc (128), and has a = 8.960(3) Å, c = 15.767(7) Å and V = 1265.80(11) Å3. The terms identified represent a solid solutions series between the two end-members, fluorapophyllite and hydroxyapophyllite. Manganoan ilvaite, CaFe2+Fe3+(Fe2+, Mn)(Si2O7)(O)(OH), crystallizes in the space group Pnam (62), and has as unit-cell parameters: a = 13.008(7) Å; b = 8.865(5) Å; c = 5.845(3) Å, V = 674.02(9) Å3. The textural relations of inesite /hubeite/ruizite /apophyllite/manganoan ilvaite assemblage show that the oldest mineral is manganoan ilvaite, as inesite and hubeite overgrow and engulf this mineral. Hubeite is indicative for mildly oxidizing crystallization, conditions. Both hubeite and ruizite are Ca-Mn hydrated silicates. However, all Mn is divalent in hubeite and trivalent in ruizite. In addition, ruizite is Fe-free, whereas hubeite contains significant Fe3+. Ruizite Ca2Mn3+Si4O11(OH)4.2H2O was formed under higher oxidizing conditions as compared with hubeite. Sudoite and specularite also occurs in this oxidized assemblage. Sudoite, Mg2(Al.Fe3+)3Si3O10(OH)8, is monoclinic and has as space group C2m (12) and as unit-cell parameters a = 5.237(2) Å, b = 9.070(5) Å, c = 14.285(8), β = 97.00, V = 673.47(14) Å3. The carbonate closely associated to this assemblage is a Mn- and Ca-bearing siderite, which crystallizes in space group R-3c (167), having as unit-cell parameters: a = 4.694(1) Å; c = 15.386(5) Å, and V = 293.53(13) Å3. The secondary minerals occurring in this assemblage as determined by X-ray powder diffraction are: gold, sphalerite, pyrite, and galena. The origin of vein assemblage inesite /hubeite /ruizite /apophyllite is hydrothermal (epithermal); there exist indications of a genesis at low temperature, around 200°C. The assemblage indicated before is grown on manganoan ilvaite, which is the oldest mineral in this association. There are no signs of the genesis of manganoan ilvaite /inesite /hubeite /ruizite assemblage at the expense of higher T anhydrous manganese minerals such as rhodonite or johannsenite.

Synthesis, crystal structure, and photoluminescence of the new nitridoboroaluminosilicate phosphor (Sr0.93Eu0.07)11B2(Al0.275Si0.725)40N59

Single crystals of a new nitride, (Sr0.93Eu0.07)11B2(Al0.275Si0.725)40N59, were synthesized by heating a mixture of binary nitride powders at 2030 ​°C under nitrogen gas at 0.85 ​MPa. The fundamental X-ray diffraction reflections from a single crystal were indexed with the monoclinic cell parameters a ​= ​5.6836(4) Å, b ​= ​46.772(3) Å, c ​= ​5.6845(4) Å, and β = 118.028(2)° and diffuse streaks were observed between the reflections. The crystal structure was analyzed based on a statistical average structural model with space group Cm. The structure was determined to comprise (Al/Si)N4 tetrahedra and BN3 planar triangles forming a three-dimensional framework by sharing nitrogen atoms with Sr/Eu atoms located in the cage portions of the framework. Stacking faults in the b-axis direction and disordered atomic arrangements along the [1 0 1] direction on the a-c plane were observed by scanning transmission electron microscopy. These single crystal grains were found to emit red light when irradiated with near ultraviolet or blue light, with a maximum emission wavelength of 616 ​nm and a full width at half-maximum value of 106 ​nm in response to 450 ​nm light.

Effect of B-site dopants on the structure and band gap in SrLaLiTeO6

Li and Te doping at the B and B’ sites of SrLaLi1-xTe1+xO6 and its effect on the structure and band gap were investigated for the first time for −0.2 ≤ x ≤ 0.2. All the samples were found to be crystallized in the monoclinic structure with space group P21/n thereby suggesting the formation of a double perovskite. The cell volume is seen to vary almost linearly for all compositions authenticating the formation of single-phase. A deviation from pseudo-cubic symmetry is observed from Li rich to Te rich compositions in terms of the monoclinic cell angle. A linear variation in the tolerance factor suggests that the doping of Te for Li permits for a better matching of the Sr/La-O and Li/Te-O bond distances as compared to Li for Te doping. Optical band gap measurements indicate a reduction in the width of the conduction band causing a rise in the energy Eg.

Pentagraphite C8 : An all- sp2 topological nodal-line semimetal

Recent research predicted stable two-dimensional pentagraphene in $s{p}^{2}\text{\ensuremath{-}}s{p}^{3}$ bonding states and three-dimensional pentadiamond (BC14) in all-$s{p}^{3}$ bonding states, both comprising five-membered carbon-ring networks and exhibiting semiconducting character with sizable electronic band gaps. Here we identify by ab initio calculations an all-$s{p}^{2}$ carbon allotrope, also comprising the unusual five-membered rings as the basic structural units, with an eight-atom monoclinic primitive cell in $C2/m$ (${C}_{2h}^{3}$) symmetry, termed mpg-${\mathrm{C}}_{8}$ pentagraphite. Total-energy calculations show that mpg-${\mathrm{C}}_{8}$ is more stable than or comparable to the previously reported all-$s{p}^{2}$ rh6 polybenzene and all-$s{p}^{3}$ BC14 pentadiamond. Electronic band calculations reveal that mpg-${\mathrm{C}}_{8}$ is a topological nodal-line semimetal protected by the inversion ($P$) and time reversal ($T$) symmetry, comprising two nodal rings centered at the $\mathrm{\ensuremath{\Gamma}}$ and $M$ points in the bulk first Brillouin zone and one projected surface flat band around the Fermi level on its (010) surface. These results establish a distinct type of carbon phase with nontrivial topological properties and offer insights into its outstanding electronic properties.

Zn/Al-centered tetrahedral framework oxide Ba4Zn2Al2O9

Single crystals of Ba4Zn2Al2O9 were obtained by heating a mixture of BaCO3, ZnO, and Al2O3 at 1413 ​K in a dry air atmosphere. X-ray crystal structure analysis revealed that the compound crystalizes in a monoclinic cell (a ​= ​6.9444(2) Å, b ​= ​5.91650(10) Å, c ​= ​13.5842(3) Å, β ​= ​103.955(1)°) with the space group P21/n. The crystal structure can be characterized as a substitution of Zn/AlO4 tetrahedra for B-cation-centered O octahedra of a perovskite-type structure (ABO3). The vacant spaces surrounded by planes of the tetrahedra with eight- and ten-fold coordinations of O atoms are occupied by Ba atoms. The melting temperature (1444 ​K), electrical conductivity (1.5 ​× ​10–6 ​S ​cm–1 at 1073 ​K), relative permittivity (24 ​at 298 ​K and 1 ​MHz), and linear thermal expansion coefficient (9.72 ​× ​10–6 ​K–1 ​at 298–873 ​K) of a polycrystalline bulk sample were measured.

Structural investigations of halogen substituted 1,4-dihydropyridine derivatives: Crystallographic and computational studies

Single crystal structure solution and refinement have been carried out on 1,4-dihydropyridine derivative molecules, namely, 4-(4‑chloro-phenyl)-2,6-dimethyl-1, 4-dihydropyridine-3,5-dicarboxylic acid bis-[(2-chlorophenyl)amide] and 4-(4-fluoro-phenyl)-2,6-dimethyl-1, 4-dihydropyridine-3,5-dicarboxylic acid bis-[(2-chlorophenyl)amide]. Final refinement values, of [I > 2σ(I)] (all data) were refined as 0.0608 (0.0768) and 0.0595 (0.0696) for M-Cl and M-F. Hirshfeld surfaces analysis mapped dnorm surfaces, shape index, curvedness and hydrogen bonding in both the molecules and major relative contributions to the percentage of Hirshfeld surface area for the various intermolecular contacts were calculated. DFT studies using Quantum ESPRESSO were carried out by transformation of the conventional monoclinic unit cell to the primitive unit cell converted back to the original monoclinic cell to compare with the experimental data. The NBO analysis implemented in Gaussian was used to know intermolecular force between two molecular units and to obtain the stabilization energies from donors to acceptors in M-Cl and M-F. The natural localized molecular orbital (NLMO) analysis was also performed to capture the intermolecular delocalization interactions of NBOs.

Cu9O2(SeO3)4Cl6 revisited: Crystal structure, Raman scattering and first-principles calculations

Chloromenite, Cu9O2(SeO3)4Cl6, is the product of volcanic activity. To conduct various physical studies both natural and synthetic samples of chloromenite were used which resulted in a long-standing controversy regarding its crystal structure. We carried out the temperature dependent single crystal X-ray diffraction study in the range 100 – 370 K and established that the reflection conditions are consistent with a primitive monoclinic cell with the only possible P21/n space group. Raman scattering evidences a complex interplay of crystal lattice and spin degrees of freedom. The observation of a sequence of short range fluctuation effects points to the existence of competing interactions or nearly degenerate energy scales. To gain microscopic understanding of the magnetic properties of Cu9O2(SeO3)4Cl6 the first principles density functional theory calculations have been performed. Basing on the new data on magnetization and the hierarchy of exchange interaction parameters a model of Cu9O2(SeO3)4Cl6 magnetic structure is suggested.

Thermal Deformations of Crystal Structures in the L-Aspartic Acid/L-Glutamic Acid System and DL-Aspartic Acid

The method of temperature-resolved powder X-ray diffraction (TRPXRD) was used to determine the elevated temperature behavior of L-aspartic acid (L-asp), DL-aspartic acid (DL-asp), L-glutamic acid (L-glu), and an L-asp0.25,L-glu0.75 solid solution. These amino acids were not found to undergo any solid-phase (polymorph) transformations. When heated, they all experienced only thermal deformations. The corresponding parameters of the monoclinic cells of L-asp and DL-asp, and the orthorhombic cells of L-glu and L-asp0.25,L-glu0.75, were calculated for the entire range of studied temperatures (up to 220 °C). The data obtained were used to calculate the parameters of the thermal deformation tensors, and to plot the figures of their thermal expansion coefficients. A correlation between the maximum and minimum values of thermal expansion coefficients and the length, type, direction, and number of hydrogen bonds in the crystal structures of the investigated amino acids was established. The observed negative thermal expansion (contraction) of crystal structures of L-asp and DL-asp along the ac plane can be explained as a result of shear deformations occurring in monoclinic crystals with a non-fixed angle β. The studies were related to the presence of amino acids in various natural and technological processes occurring at different temperatures.

Structural, Spectroscopic, Antiferromagnetic and in vitro antiproliferative studies of copper (II) pyrophosphate complex against Human breast cancer cell lines

In purpose to search for compounds of biological interest, we have succeeded in synthesizing a copper complex with polypyridine ligands. The architecture of the compound consists of O, N-donor entities, the pyrophosphate anion HP2O73− and the two heterocyclic molecules, 1,10-phenanthroline and 2,2′-bipyridine. X-ray diffraction study proves that our compound crystallizes in a monoclinic cell of space group P21/n. The atomic arrangement can be described by the aggregation of [(C10H8N2)(C12H10N2)Cu2(H2O)2(HP2O7)]+ cation, which contributes to the macrocyclic compound-complex. The second sphere of the cationic complex is localized the anion ClO4− to complete the neutrality. Magnetic studies show an antiferromagnetic coupling exchange between metal copper ions which mediated throw neighboring oxygen atom belonging from the pyrophosphate anion. The biological antiproliferative activity of the sample shows a relatively high cytotoxicity IC50 respectively toward MCF-7 breast cancer cell lines.