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Four new solvatomorphs of betulin were reported and characterized by X-ray diffractometry as well as thermal and vibrational spectroscopic analyses. Single-crystal X-ray diffraction was used to analyze the X-ray structures of the compounds and confirmed the stoichiometric ratio between the host and guest molecules from thermal data. Results indicated that solvatomorphism occurred in several betulin solvates. Changes in intermolecular arrangements, stoichiometry, and hydrogen-bonding interactions of solvatomorphs were due to solvent incorporation to solvates. Hirshfeld surface analyses, especially d norm surface and fingerprint plots, were used to determine intermolecular interactions in the crystal network. Solvent molecules played an important role in the construction of a 3D architecture. The stabilities of these solvates were evaluated by thermal analyses. Nonisothermal kinetic analysis was used to explain the kinetics of solid-solid phase transition (desolvation) of betulin solvates. The apparent activation energies were evaluated using Kissinger and Ozawa methods. Moreover, phase transitions were visually investigated by hot-stage microscopic analysis., (Copyright © 2017. Published by Elsevier Inc.)

Lead–calcium phosphates are unusual compounds sometimes found in different kinds of cultural heritage objects. Structural and physicochemical properties of this family of materials, which fall into the hydroxypyromorphite–hydroxyapatite solid solution, or (Pb x Ca1− x )5(PO4)3OH, have received considerable attention during the last few decades for promising applications in different fields of environmental and material sciences, but their diagnostic implications in the cultural heritage context have been poorly explored. This paper aims to provide a clearer understanding of the relationship between compositional and structural properties of the peculiar series of (Pb x Ca1− x )5(PO4)3OH solid solutions and to determine key markers for their proper non-destructive and non-invasive identification in cultural heritage samples and objects. For this purpose, a systematic study of powders and paint mock-ups made up of commercial and in-house synthesized (Pb x Ca1− x )5(PO4)3OH compounds with a different Pb2+/Ca2+ ratio was carried out via a multi-technique approach based on scanning electron microscopy, synchrotron radiation-based X-ray techniques, i.e., X-ray powder diffraction and X-ray absorption near edge structure spectroscopy at the Ca K- and P K-edges, and vibrational spectroscopy methods, i.e., micro-Raman and Fourier transform infrared spectroscopy. The spectral modifications observed in the hydroxypyromorphite–hydroxyapatite solid solution series are discussed, by assessing the advantages and disadvantages of the proposed techniques and by providing reference data and optimized approaches for future non-destructive and non-invasive applications to study cultural heritage objects and samples. [ABSTRACT FROM AUTHOR]

Propiolamide and cellocidin were investigated in superacidic media. In both acetylenic amides, the amide moiety is immediately monoprotonated in anhydrous HF, HF/SbF5 and HF/BF3. An increase of SbF5 does not lead to a more highly protonated species. The salts were characterized by low-temperature Raman, NMR and room temperature IR spectroscopy, as well as by single-crystal X-ray diffraction. The experimental data are discussed together with results of quantum-chemical calculations on the M06-2X/aug-cc-pVTZ level of theory, which are consistent with the observation of pure monoprotonation. The second protonation of the amide moiety or the triple bond is not observed due to the high positive charge caused by the monoprotonation. [ABSTRACT FROM AUTHOR]

A novel 0D organic–inorganic hybrid antimony-based halide [((R)-C8H12N)4](Sb2Cl10) was achieved through a slow evaporation method at room temperature. Single crystal X-ray diffraction analysis revealed that the compound crystallizes in the monoclinic system, within the P21 space group. The structure consists of(R)-1-phenylethylammonium (C8H12N)+cations and [Sb2Cl10]4− dimers, formed by edge-sharing distorted octahedra. The cohesion of the structure were ensured by N-H…Cl hydrogen bonds. Hirshfeld surface analysis indicated H…H interactions as the dominant intermolecular interaction contacts (42.4 %). Infrared and Raman spectroscopy confirmed the presence of organic cations and inorganic components. The thermogravimetric analysis demonstrated that the compound exhibits thermal stability up to 180 °C. Finally, Optical studies further suggest that this material holds significant promise for optical and optoelectronic applications.

Bismuth-halide-based hybrid materials are desirable in luminescent applications due to low toxicity and chemical stability. (C8H12N)4Bi2Cl10, was elaborated by the slow evaporation technique at room temperature. Single-crystal X-ray diffraction analysis indicates that the compound belongs to the monoclinic crystal system with the centrosymmetric space group P21/c. The formula unit comprises four protonated organic cations (C8H12N)4+, one [Bi2Cl10]4− dimer. The organic layers are inserted between the inorganic ones and connected with N-H…Cl and C-H…Cl hydrogen bonds to build a three dimensional network. The infrared IR and Raman studies which were recorded at room temperature in the 500–4000 cm−1 and 50–4000 cm−1 frequency regions, respectively, confirmed the existence of vibrational modes that correspond to the organic and inorganic groups. The optimized molecular structure and vibrational frequencies were calculated by the Density Functional Theory (DFT) method using the B3LYP level employing level employing a LANL2DZbasis set. It shows a good agreement between the calculated and the experimental vibrational frequencies. Hirshfeld surface analysis of close intermolecular interactions in this compound enables the identification and examination of molecular shapes. The crystal exhibits thermal stability up to 160 °C using the Thermogravimetric analysis TGA. The optical properties were characterized experimentally by UV–visible absorption studies and photoluminescence measurements. The Photoluminescence spectrum shows a green luminescence peak which is attributed to excitonic emissions within the chlorobismuthate octahedron. HOMO-LUMO orbital energies were studied by using DFT calculations.

The coordination properties of the scorpionate ligand 2-PyCH[P(O)Ph2]2 were studied using complexation with neodymium nitrate as an example. The molecular structure of the [Nd{(2-PyCH[P(O)Ph2]2}(NO3)3(H2O)] complex was determined by X-ray diffraction analysis. The structures of the ligand and the complex were studied in the solid state and in solutions by vibrational and multinuclear (1H, 13C, 31P) NMR spectroscopy. The tridentate O,O,N-coordination of the ligand found in the crystal is retained in solution. [ABSTRACT FROM AUTHOR]

Cyclic dipeptides with two intramolecular peptide bonds forming a six-membered 2,5-diketopiperazine ring are gaining significant attention due to their biological and chemical properties. Small changes in the local geometry of such molecules (from cis to trans) can lead to significant structural differences. This work presents the results of a study of cyclo(l-Cys-d-Cys), a dipeptide comprising two cysteine molecules in opposite chiral configurations, with the functional groups situated at both sides of the diketopiperazine ring. X-ray diffraction (XRD) experiment revealed that the molecule crystallises in the P-1 space group, which includes the centre of inversion. The IR and Raman vibrational spectra of the molecule were acquired and interpreted in terms of the potential energy distribution (PED) according to the results of density functional theory (DFT) calculations. The DFT-assisted analysis of energy frameworks for the hydrogen bond network within molecular crystals was performed to support the interpretation of X-ray structural data. The optimisation of the computational model based on three-molecule geometry sections from the crystallographic structure, selected to appropriately reflect the intermolecular interactions responsible for the formation of 1D molecular tapes in cyclo(l-Cys-d-Cys) crystal, allowed for better correspondence between theoretical and experimental vibrational spectra. This work can be considered the first complete structural characterisation of cyclo(l-Cys-d-Cys), complemented via vibrational spectroscopy results with full band assignment aided with the use of the DFT method. [ABSTRACT FROM AUTHOR]

• New organic-inorganic hybrid material (C 8 H 12 N) 4 [SbCl 5 ] 2 was synthesized by slow evaporation. • Hirshfeld surface analysis was used to study the various types of intermolecular interactions and their impact towards the crystal packing. • Anionic and cationic groups are linked via N–H...Cl hydrogen bonds. • The optimized geometry and vibrational frequencies were calculated by the use of density functional theory (DFT) using B3LYP method. • Assignments of IR and Raman wavenumbers were made on the basis of potential energy distribution (PED) using vibrational energy distribution analysis (VEDA). • Optical absorption properties were analyzed and assigned. • The HOMO–LUMO energies and related molecular properties were evaluated. The new centrosymmetric hybrid material (C 8 H 12 N) 4 [SbCl 5 ] 2 has been successfully elaborated at room temperature by slow evaporation in the centrosymmetric monoclinic space group P2 1 /c with the following parameters: a = 29.0349(16) Å, b = 13.1241(7) Å, c = 12.0278(7) Å, β = 95.567(2) ° Z = 4 and V = 4561.7(4) Å3. The asymmetric unit consists of two isolated [Sb 2 Cl 10 ]4- dimers and four protonated cations (C 8 H 12 N)+ was optimized d by density functional theory (DFT) using the B3LYP method. The cohesion of this supramolecular material was ensured by the means of N—H...Cl hydrogen-bonding interactions yield a three-dimensional network. The infrared IR and Raman studies which were performed at room temperature charge in the 4000–400 cm -1 and 10- 3000 cm -1 frequency regions, respectively, displayed the existence of vibrational modes that correspond to the organic and inorganic groups. The assignment of wavenumbers which were based on potential energy distribution (PED), were performed using Vibrational Energy Distribution Analysis (VEDA) software. Actually, the values obtained by the B3LYP/LanL2MB are in good agreement with the experimental data. Moreover, the Hirschfeld surfaces analysis which was employed to identify the different intermolecular interactions, showed that predominate interactions were H...Cl. The Thermogravimetric analysis (TGA) reveals the decomposition of the compound remains stable above 175 °C that confirms its great thermal stability. Furthermore, the optical property of the 0D hybrid Sb(III) based halide was studied with a focus on the band gap. Theoretical investigations on the electronic structure, Simulated UV–Visible spectrum, band gap, and frontier molecular orbitals (FMOs) were undertaken using density functional theory (DFT) and time-dependent DFT (TD-DFT). Therefore, our results indicate an acceptable consistency was found between calculations and experimental results leading to consistent vibrational and optical features assignments as well as the energy gap (Eg) and the chemical reactivity descriptors which are primarily linked to the ring of the organic cation and the inorganic anion. [ABSTRACT FROM AUTHOR]

[Display omitted] • New organic-inorganic hybrid material (C5H8N6)6[Bi2Cl11].7Cl.4H2O was synthesized by slow evaporation. • The atomic arrangement shows a zero-dimensional network. • Anionic and cationic groups are linked via hydrogen bonds. • The infrared spectra, the photoluminescence, the thermal behaviour and the optical absorption spectrum were analyzed and assigned by theoretical studies. The new hybrid bismuth(III)-based material (C 5 H 8 N 6) 6 [Bi 2 Cl 11 ].7Cl·4H 2 O has been synthesized and crystallized at room temperature by slow evaporation in the triclinic space group P 1̅ with the parameters: a = 11.5777(3)Å, b = 12.0847 (4)Å, c = 15.2286 (4) Å, β = 108.571 (6)°, Z = 2 and V = 1132.6 (2) Å3. The crystal structure consists of discrete Bi 2 Cl 11 dioctahedral anions, four chloride surrounded by three 2,6 diaminopurinium cations, and two molecules of water were optimize by density functional theory (DFT) using the B3LYP method. The atomic arrangement can be described as an alternation of organic and inorganic parts which are linked via N H...Cl and O H...Cl hydrogen bonds, and offset π-π stacking interaction, form a three-dimensional network. The infrared and Raman spectra were recorded in the 4000–500 cm−1 and 3000–10 cm−1 frequency regions, respectively. Moreover, Theoretical investigations on the electronic structure, Simulated UV–visible spectrum, band gap, and frontier molecular orbitals (FMOs) were undertaken using density functional theory (DFT) and time-dependent DFT (TD-DFT). Our results indicate a satisfactory agreement between calculations and experimental results. Furthermore, the thermal behavior studied by thermogravimetric analyses shows good stability up to 170 °C. Finally, photoluminescence measurement indicates that the synthesized material manifests luminescence property and can be practical for use in the optoelectronics domain. [ABSTRACT FROM AUTHOR]

Monoclinic TeB4O8 was obtained in a Walker‐type multianvil apparatus at 10 GPa and 1273 K from TeO2 and B2O3. It crystallizes isotypically to the compounds AnB4O8 (An=Th, U) in the space group C2/c (Z=4) with the lattice parameters a=15.6978(8) Å, b=4.2284(2) Å, c=7.4305(4) Å, β=114.78(1)°, and V=447.80(4) Å3. Further, it has been characterized via X‐ray diffraction experiments and IR spectroscopy. [ABSTRACT FROM AUTHOR]

Monoclinic TeB4O8 was obtained in a Walker‐type multianvil apparatus at 10 GPa and 1273 K from TeO2 and B2O3. It crystallizes isotypically to the compounds AnB4O8 (An=Th, U) in the space group C2/c (Z=4) with the lattice parameters a=15.6978(8) Å, b=4.2284(2) Å, c=7.4305(4) Å, β=114.78(1)°, and V=447.80(4) Å3. Further, it has been characterized via X‐ray diffraction experiments and IR spectroscopy. [ABSTRACT FROM AUTHOR]

Cyclic dipeptides with two intramolecular peptide bonds forming a six-membered 2,5-diketopiperazine ring are gaining significant attention due to their biological and chemical properties. Small changes in the local geometry of such molecules (from cis to trans) can lead to significant structural differences. This work presents the results of a study of cyclo(l-Cys-d-Cys), a dipeptide comprising two cysteine molecules in opposite chiral configurations, with the functional groups situated at both sides of the diketopiperazine ring. X-ray diffraction (XRD) experiment revealed that the molecule crystallises in the P-1 space group, which includes the centre of inversion. The IR and Raman vibrational spectra of the molecule were acquired and interpreted in terms of the potential energy distribution (PED) according to the results of density functional theory (DFT) calculations. The DFT-assisted analysis of energy frameworks for the hydrogen bond network within molecular crystals was performed to support the interpretation of X-ray structural data. The optimisation of the computational model based on three-molecule geometry sections from the crystallographic structure, selected to appropriately reflect the intermolecular interactions responsible for the formation of 1D molecular tapes in cyclo(l-Cys-d-Cys) crystal, allowed for better correspondence between theoretical and experimental vibrational spectra. This work can be considered the first complete structural characterisation of cyclo(l-Cys-d-Cys), complemented via vibrational spectroscopy results with full band assignment aided with the use of the DFT method.

The syntheses of [H3C(O)CC(OH)2][MF6] and [H3C(OH)CC(OH)2][MF6]2 (M=As, Sb) by reacting pyruvic acid in the superacidic systems HF/AsF5 and HF/SbF5 are reported. The salts were characterized by low‐temperature vibrational spectroscopy and in the cases of [H3C(O)CC(OH)2][SbF6] and [H3C(OH)CC(OH)2][SbF6]2 ⋅ HF by X‐ray crystal structure analyses. The experimental results are discussed together with quantum chemical calculations. Remarkably, the bond distance and the twisting angle around the central C−C bond are unaffected by the protonations despite increasing coulombic repulsion. The crystal structure reveals short interionic interactions that have a considerable influence on the C−C bond. [ABSTRACT FROM AUTHOR]

• ((S)-C 8 H 12 N) 4 Sb 2 I 10 is a new zero dimensional hybrid compound. • Vibrational properties were studied by infrared spectroscopy and by DFT calculation. • Thermal decomposition was studied by TGA. • Optical absorption properties of ((S)-C 8 H 12 N) 4 Sb 2 I 10 were determined. Hybrid metal halides have captured broad interest in the lighting and display fields because of their unique electronic structures and splendid broadband emission properties. Organic chiral building blocks can control light, charge, and spin interconversion in hybrid crystalline semiconductors with metal-halide.Based on the chiral organic molecules(S)-1-phenylethylamine, we synthesized new chiral antimony halidewith zero-dimensional structure((S)-C 8 H 12 N) 4 Sb 2 I 10. Atroom temperature, the title compound is crystallized in the monoclinic P2 1 with Z = 2 and the following unit cell dimensions: a = 12.69129 (15) Å, b = 14.96770 (15) Å, c = 13.91397 (16) Å, and β = 92.2735 (11)°.The crystal structure of this compound is composed of two crystallographically independent [Sb 2 I 10 ]4- unit and four (S)-1-phenylethylammonium per unit cell. The crystal packing is governed by N H....I hydrogen bonds.Intermolecular interactions seen in the grown single crystal are studied by Hirshfeld surface and 2-D fingerprint plot.In addition to study the weak interaction a visualized approach known as RDG has been carried out.The recorded infrared IR and Raman studies confirm vibrational modes for organic and inorganic groups at room temperature in the 500–4000 cm−1 and 50–4000 cm−1 frequency regions, respectively.The optimized molecular structure and vibrational frequencies were calculated by the Density Functional Theory (DFT) method using the B3LYP level employing a LANL2DZbasis set.The title compound reveals thermal stability up to 190 °C.The opticalabsorption measurement confirms the semiconductor nature with a band gap of around 3.74 eV. The frontier molecular orbital analysis HOMO-LUMOof molecule were studied. [Display omitted] [ABSTRACT FROM AUTHOR]

The amides Na3RE(NH2)6 have been obtained from the metals in supercritical ammonia under ammonobasic conditions at 573 K and 70 MPa for RE = La–Nd, and at 473 K and 40 MPa for RE = Er, Yb. All compounds are formed in the hot zone within a temperature gradient, indicating a retrograde solubility under the applied process conditions. These amides represent soluble intermediates in ammonothermal binary rare earth metal nitride synthesis. All compounds were obtained as microcrystalline powders, while single crystals of those amides containing the heavier rare earth metals could be isolated. The crystal structures were solved and refined from single-crystal and powder X-ray diffraction intensity data. The results of vibrational spectroscopy are reported. Thermal analysis measurements under inert gas atmosphere demonstrated a decomposition to the respective black binary rare earth metal nitrides REN1−δ. [ABSTRACT FROM AUTHOR]

Acetylenedicarboxylic acid (C4H2O4) was protonated in the binary superacidic systems HF/MF5 (M=As, Sb). Depending on the stoichiometric ratio of Lewis acid and acetylenedicarboxylic acid mono‐ and diprotonated acetylenedicarboxylic acid was obtained. The salts of diprotonated acetylenedicarboxylic acid were characterized by vibrational spectroscopy and in case of [C4H4O4][SbF6]2 by a single‐crystal X‐ray structure analysis. The salt crystallizes in the monoclinic space group C2/c with four formula units per unit cell. Furthermore, salts of monoprotonated acetylenedicarboxylic acid were synthesized and characterized by single‐crystal X‐ray structure analysis. The salts [C4H3O4][AsF6] and [C4H3O4][SbF6] crystallize in the monoclinic space group C2/c with four formula units per unit cell. The monoprotonation is better described as a twofold hemiprotonation of acetylenedicarboxylic acid. The experimental results are discussed together with quantum chemical calculations. [ABSTRACT FROM AUTHOR]

Abstract Difluorothiophosphoryl isocyanate, F2P(S)NCO was characterized with UV/vis, NMR, IR (gas and Ar‐matrix), and Raman (liquid) spectroscopy. Its molecular structure was also established by means of gas electron diffraction (GED) and single crystal X‐ray diffraction (XRD) in the gas phase and solid state, respectively. The analysis of the spectroscopic data and molecular structures is complemented by extensive quantum‐chemical calculations. Theoretically, the Cs symmetric syn‐conformer is predicted to be the most stable conformation. Rotation about the P−N bond requires about 9 kJ mol−1 and the predicted existence of an anti‐conformer is dependent on the quantum‐chemical method used. This syn‐orientation of the isocyanate group is the only one found in the gas phase and contained likewise in the crystal. The overall molecular structure is very similar in gas and solid, despite in the solid state the molecules arrange through intramolecular O⋅⋅⋅F contacts into layers, which are further interconnected by S⋅⋅⋅N, S⋅⋅⋅C and C⋅⋅⋅F contacts. Additionally, the photodecomposition of F2P(S)NCO to form CO, F2P(S)N, and F2PNCO is observed in the solid Ar‐matrix.

• A new hybrid compound Bis (2-amino-3-nitropyridinuim) pentachloroantimoinates (III) was analyzed using XRD. • Assignments of IR and raman were made. • Thermal decomposition was studied by TGA. • Optical absorption properties of [C 5 H 6 N 3 O 2 ]SbCl 5 were determined. A novel interesting hybrid organic-inorganic material of Bis (2-amino-3-nitropyridinuim) pentachloroantimoinates (III) with the formula [C 5 H 6 N 3 O 2 ] 2 SbCl 5 was elaborated by slow evaporation at room temperature. This compound was crystallized in the monoclinic system with the P 2 1 /c space group, as shown using the X-ray diffraction results. The parameters are the following: a = 16.484(6) Å, b = 7.7170 (19) Å, c = 16.159 (7) Å, β= 109.26(5)°, Z = 4 and V = 1940,5(14) Å3. The asymmetric unit consists of one Sb (III) cation surrounded by five Cl− and two protonated cations 2-amino-3-nitropyridinuim. The crystal packing cohesion was maintained by N H...Cl and N H...O hydrogen bonds to form a three- dimensional network. The infrared IR and Raman studies which were recorded at room temperature in the 4000–400 cm−1 and 0–4000 cm−1 frequency regions, respectively, confirmed the existence of vibrational modes that correspond to the organic and inorganic groups. The Hirshfeld analysis results show that the predominate interactions were H...Cl and O...H contacts (39.9, 14.5 % respectively). The Thermogravimetric analysis TGA shows that this compound remains stable up to about 150 °C. The optical properties were characterized experimentally by UV–visible absorption studies and photoluminescence measurements. The Photoluminescence spectrum manifests a broad and strong band of luminescence around 454 nm (2.73 eV), which can be even observed with the naked eye at room temperature and is due to exciton emission. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract We report the crystal structure of Ba(CN3H4)2 as synthesized from liquid ammonia. Structure solution based on X‐ray diffraction data suffers from a severe pseudo‐tetragonal problem due to extreme scattering contrast, so the true monoclinic symmetry is detectable only from neutron powder diffraction patterns, and structure solution and refinement was greatly aided by density‐functional theory. The symmetry lowering is due to slight deviations of the guanidinate anion from the mirror plane in space group P4‾ b2, a necessity of hydrogen bonding. At 300 K, barium guanidinate crystallizes in P21/c with a=6.26439(2) Å, b=16.58527(5) Å, c=6.25960(2) Å, and a monoclinic angle of β=90.000(1)°. To improve the data‐to‐parameter ratio, anisotropic displacement parameters from first‐principles theory were incorporated in the neutron refinement. Given the correct structural model, the positional parameters of the heavy atoms were also refinable from X‐ray diffraction of a twinned crystal. The two independent guanidinate anions adopt the all‐trans‐ and the anti‐shape. The Ba cation is coordinated by eight imino nitrogens in a square antiprism with Ba−N contacts between 2.81 and 3.04 Å. The IR and Raman spectra of barium guanidinate were compared with DFT‐calculated phonon spectra to identify the vibrational modes.

We report theoretical and experimental investigations on the structures of strontium and magnesium oxalates, and corresponding Raman spectra at high pressure. These systems have shown progress in the generation of CO2 and in the synthesis of energetic doped polymeric carbon monoxide after X-ray irradiation and simultaneous application of high pressure. Density functional perturbation theory (DFT) was used to calculate the zone center optical phonons in monoclinic and triclinic strontium oxalate, and the ambient triclinic phase of magnesium oxalate. Vibration modes were also determined in terms of atomic displacements for both compounds. The simulations were compared to experimental Raman spectra in an effort to elucidate the details of the phase transition between monoclinic and triclinic phases. Additional phonon dispersion calculations of the compounds were performed to gain better insight into the dynamic phase stability in strontium and magnesium oxalates under high pressure. [ABSTRACT FROM AUTHOR]

Difluorothiophosphoryl isocyanate, F2P(S)NCO was characterized with UV/vis, NMR, IR (gas and Ar‐matrix), and Raman (liquid) spectroscopy. Its molecular structure was also established by means of gas electron diffraction (GED) and single crystal X‐ray diffraction (XRD) in the gas phase and solid state, respectively. The analysis of the spectroscopic data and molecular structures is complemented by extensive quantum‐chemical calculations. Theoretically, the Cs symmetric syn‐conformer is predicted to be the most stable conformation. Rotation about the P−N bond requires about 9 kJ mol−1 and the predicted existence of an anti‐conformer is dependent on the quantum‐chemical method used. This syn‐orientation of the isocyanate group is the only one found in the gas phase and contained likewise in the crystal. The overall molecular structure is very similar in gas and solid, despite in the solid state the molecules arrange through intramolecular O⋅⋅⋅F contacts into layers, which are further interconnected by S⋅⋅⋅N, S⋅⋅⋅C and C⋅⋅⋅F contacts. Additionally, the photodecomposition of F2P(S)NCO to form CO, F2P(S)N, and F2PNCO is observed in the solid Ar‐matrix. [ABSTRACT FROM AUTHOR]

γ-Sm(BO2)3 was obtained via a high-pressure/high-temperature approach in a multi-anvil apparatus at 10 GPa and 1673 K. It crystallizes in the orthorhombic space group Pca21 (no. 29) with the lattice parameters a = 18.3088(8), b = 4.4181(2), and c = 4.2551(2) Å. The compound was analysed by means of X-ray diffraction and vibrational spectroscopy. The structure is isotypic to that of the already known meta-oxoborates γ-RE(BO2)3 (RE = La−Nd) and built up of a highly condensed borate framework containing three-, four-, six-, and ten-membered rings. Next to neodymium, samarium represents the second rare earth element that forms the α-, β-, and γ-modification of the four known rare earth meta-oxoborate structure types. [ABSTRACT FROM AUTHOR]

γ-Sm(BO2)3 was obtained via a high-pressure/high-temperature approach in a multi-anvil apparatus at 10 GPa and 1673 K. It crystallizes in the orthorhombic space group Pca21 (no. 29) with the lattice parameters a = 18.3088(8), b = 4.4181(2), and c = 4.2551(2) Å. The compound was analysed by means of X-ray diffraction and vibrational spectroscopy. The structure is isotypic to that of the already known meta-oxoborates γ-RE(BO2)3 (RE = La−Nd) and built up of a highly condensed borate framework containing three-, four-, six-, and ten-membered rings. Next to neodymium, samarium represents the second rare earth element that forms the α-, β-, and γ-modification of the four known rare earth meta-oxoborate structure types. [ABSTRACT FROM AUTHOR]

The new organic–inorganic hybrid material (C6H7N2S)2[SbCl4]Cl was synthesized by slow evaporation method and characterized by single-crystal X-ray diffraction, infrared absorption, Hirshfeld surface analysis, optical absorption and photoluminescence measurements. The Centro symmetric compound crystallizes in the triclinic system of space group P 1 ¯ with two formula units cell (Z = 2).The crystal structure is composed of a discrete [SbCl4]− anion and two isolated chloride Cl− anions which carried the same negative charge to balance the total charge of this compound surrounded by the 4 pyridiniumethioamide cations. Organic and inorganic parts which are linked by means of hydrogen bonding contacts N–H···Cl with N···Cl length are varied in the range of 3.221–3.456 Å to form a Zero-dimensional network. The infrared study performed at room temperature charge in the 4000–400 cm−1 frequency regions confirms the existence of the organic cation [C6H7N2S]+ and that of the [SbCl4]− anion. The Photoluminescence spectrum exhibits a broad and strong band of luminescence located at 1.95 eV (635 nm), which can be even observed with the naked eye at room temperature and is due to exaction emission. The various intermolecular interactions of the two independent cations and six chloride atoms were examined via Hirshfeld surface analysis. [ABSTRACT FROM AUTHOR]

Lopinavir (LPV) and ritonavir (RTV) are anti-viral drugs used in combination and commonly prepared through hot-melt extrusion techniques. Mechanical processes are greatly involved, including blending and milling. Therefore, the crystal behavior of LPV and RTV under the mechanical process is an interesting study. Here, the LPV, RTV, and their mixtures were processed by two different treatments: grinding and compression processes. The solid-state properties of the drugs were evaluated by powder x-ray diffraction (PXRD) differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy. Single-crystal XRD analysis was also carried out to confirm the packing structure in the crystal lattice. It was observed that LPV was very sensitive to the grinding process, where it tends to form an amorphous solid in both the pure and mixture forms. On the other hand, RTV has a very stable crystalline structure and was able to retain its crystallinity even under grinding. Both LPV and RTV were observed to be quite stable under compression, where both retained their crystalline form with only slight changes in their d-spacing values. This study highlighted the molecular origin of LPV and RTV crystal behavior after grinding and compression processes. [ABSTRACT FROM AUTHOR]

• Bis (2,2′- bipyridinium) tetrachloroanitimonates(III) dichloride has been synthesized and characterized. • Anionic and cationic groups are linked by N–H–Cl hydrogen bonds. • UV–vis absorption and photoluminiscence properties. A new Sb (III) halide complex, [C 10 H 10 N 2 ] 2 (SbCl 4) 2 ·2Cl has been successfully created through slow evaporation at room temperature and carefully analyzed using physicochemical methods. This compound which was examined by single-crystal X-ray diffraction, was found to crystallize in the monoclinic system, space group P2 1 /c with crystallographic parameters a= 14.1119 (8)Å, b= 14.2464 (8)Å, c= 16.140 (1)Å, β= 109.376 (1) , V= 3061.1 (3)Å3 and Z=4. The cristal lattice was composed of two distorted tetrahedron anions (SbCl 4)− and two free chloride anions which are surrounded by two independent 2,2′-bipyridinium [C 10 H 10 N 2 ]2+ cations. This later helps to balance the negative charge of the inorganic part. The way that crystal was arranged, is due to the presence of N–H...Cl hydrogen bonds give rise to a supramolecular structure with three-dimensional network. The vibrational absorption bands were identified by Infrared and Raman spectroscopy which confirm the existence of the organic cations [C 10 H 10 N 2 ]2+ and the inorganic part [SbCl 4 ] − 2Cl−. The Hirshfeld surface analysis and fingerprint plots methods were employed to identify the different intermolecular interactions in the crystal network and to determine their contribution in the crystal structure construction. The compound provides a good thermal stability up to 117 °C studied by thermogravimetric analyses. Furthermore, optical studies confirmed semiconducting properties with the detection of band gap at 3.5 eV. The compound was also exhibited photoluminescence properties. [ABSTRACT FROM AUTHOR]

The plant cell wall is a dynamic network of several biopolymers and structural proteins including cellulose, pectin, hemicellulose and lignin. Cellulose is one of the main load bearing components of this complex, heterogeneous structure, and in this way, is an important regulator of cell wall growth and mechanics. Glucan chains of cellulose aggregate via hydrogen bonds and van der Waals forces to form long thread-like crystalline structures called cellulose microfibrils. The shape, size, and crystallinity of these microfibrils are important structural parameters that influence mechanical properties of the cell wall and these parameters are likely important determinants of cell wall digestibility for biofuel conversion. Cellulose–cellulose and cellulose-matrix interactions also contribute to the regulation of the mechanics and growth of the cell wall. As a consequence, much emphasis has been placed on extracting valuable structural details about cell wall components from several techniques, either individually or in combination, including diffraction/scattering, microscopy, and spectroscopy. In this review, we describe efforts to characterize the organization of cellulose in plant cell walls. X-ray scattering reveals the size and orientation of microfibrils; diffraction reveals unit lattice parameters and crystallinity. The presence of different cell wall components, their physical and chemical states, and their alignment and orientation have been identified by Infrared, Raman, Nuclear Magnetic Resonance, and Sum Frequency Generation spectroscopy. Direct visualization of cell wall components, their network-like structure, and interactions between different components has also been made possible through a host of microscopic imaging techniques including scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. This review highlights advantages and limitations of different analytical techniques for characterizing cellulose structure and its interaction with other wall polymers. We also delineate emerging opportunities for future developments of structural characterization tools and multi-modal analyses of cellulose and plant cell walls. Ultimately, elucidation of the structure of plant cell walls across multiple length scales will be imperative for establishing structure-property relationships to link cell wall structure to control of growth and mechanics.

Seven‐coordinated (NH4)2TaF7, Rb2TaF7 and Rb3TaOF6 were synthesized in single‐crystal form and their structures were determined. A monocapped trigonal prism (CTP) or a pentagonal bipyramid (PB) of the TaF72− anion are stereochemically nonrigid and coexist in the first two compounds as a result of strong intraspheric dynamics. Upon cooling, tetragonal Rb2TaF7 undergoes a first‐order phase transition at 145 K and the seven‐coordinated polyhedron transforms into a regular CTP. The seven‐coordinated polyhedron in (NH4)2TaF7 approaches the PB configuration as the temperature decreases. Cubic elpasolite‐like Rb3TaOF6 is characterized by the simultaneous two‐state coexistence of TaOF63− of the PB shape as rigidly reoriented and as fluxional. In the former case, the central atom is disordered over the octahedron in the unit cell, allowing the determination of the short Ta—O distance, whereas in the latter case, tantalum remains in the polyhedron center, resulting in synchronous Ta—O and Ta—F stretching vibrations appearing as the infrared band at 723 cm−1. [ABSTRACT FROM AUTHOR]

Bone crystallite chemistry and structure change during bone maturation. However, these properties of bone can also be affected by limited uptake of the chemical constituents of the mineral by the animal. This makes probing the effect of bone‐mineralization‐related diseases a complicated task. Here it is shown that the combination of vibrational spectroscopy with two‐dimensional X‐ray diffraction can provide unparalleled information on the changes in bone chemistry and structure associated with different bone pathologies (phosphate deficiency) and/or health conditions (pregnancy, lactation). Using a synergistic analytical approach, it was possible to trace the effect that changes in the remodelling regime have on the bone mineral chemistry and structure in normal and mineral‐deficient (hypophosphatemic) mice. The results indicate that hypophosphatemic mice have increased bone remodelling, increased carbonate content and decreased crystallinity of the bone mineral, as well as increased misalignment of crystallites within the bone tissue. Pregnant and lactating mice that are normal and hypophosphatemic showed changes in the chemistry and misalignment of the apatite crystals that can be related to changes in remodelling rates associated with different calcium demand during pregnancy and lactation. [ABSTRACT FROM AUTHOR]

Lead iodide is one of the best room temperature radiation detector including applications in solar cell and photodetectors. Herein, we have fabricated the high-quality thin films of pure and Nd:PbI2 through a simple and cost-effective spin-coating route and investigated their key properties. X-ray diffraction study confirms the growth orientation of all films along c-axis/(001) plane and single phase of 2H-PbI2 Polytypes with the crystallites of size in range of 21–31 nm. Further confirmation of growth and phase was carried out through FT-Raman analysis. EDX and SEM mapping was also carried out to confirm the Nd doping and its homogeneity in the films. SEM provides a clear view on the surface morphology of grown films and grain size was found in the range of 54–71 nm. Optical measurement shows high transparency, i.e., ~ 90% for grown films in visible to NIR region. The direct bandgap is observed to be enhanced with Nd doping from 2.45 to 2.58 eV; however, there is another bandgap which shows reduction with doping from 2.30 to 2.24 eV. This shows the possibility of existence of sub-energy bandgap in PbI2. The stable value of refractive index is evaluated ~ 2. The value of εʹ is found to varies from 4 to 27 in the energy range of 1–2.5 eV. Optical limiting behavior of all films was also studied at two lasers of λ = 532 nm and 632.8 nm. Moreover, a device fabrication was done for electrical study and found the resistivity increases from 5.14 × 108 Ω-cm for pure to 1.18 × 109 Ω-cm for 5% Nd-doped PbI2. [ABSTRACT FROM AUTHOR]

Synthesis of NiO nanostructures in presence of different concentrations of citric acid (CA) was achieved through flash combustion technique. The NiO nanostructures formation was confirmed through X-ray diffraction analysis. At low concentrations of CA no extra peak was observed in XRD patterns, however when the CA concentration was raised to 5 and 10 g, two new extra peaks appeared at 44.6° and 51.9° which may be attributed to the presence of C. The crystallite size was noticed to reduce from 29 to 18 nm with increase in the CA concentration. All observed Raman bands were noticed to be shifted owing to the quantum size effect. EDX and SEM mapping confirm the existence of C. SEM images confirm the cubic nanocrystalline morphology for 0.5 g CA:NiO, however with increasing CA concentration a drastic change in morphology, i.e. from nanocrystals to extended nanosheets, was observed. The energy gap values were determined using Kubelka-Munk theory and found in range of 3.5–4.0 eV. An additional energy gap ∼2 eV was also noticed at higher CA concentration. The values of relative permittivity, ε r ′ , were found in the range of 18–110 for CA concentration upto 5g, however, at 10.0 g CA its value was found to be order of 104 at 2 × 105 Hz. [ABSTRACT FROM AUTHOR]

In this work we are interested in the synthesis of a new solid solution type NaPb3–xCdxCa(PO4)3; (0 ≤ x ≤ 1). The lacunar apatite series are synthesized by a solid-state reaction and studied by X-ray diffraction, infrared and Raman scattering spectroscopy, thermal gravimetric analysis, and differential scanning calorimetry. The crystal structure of these compounds was refined using the Rietveld method. These compounds crystallize in the hexagonal system (space group P63/m) with a number of units per crystal lattice Z = 2. The structure is formed by [PO4]3− tetrahedra and Pb2+/Ca2+/Cd2+ ions, which constitute the basic skeleton of the structure. The Pb2+/Ca2+/Cd2+ ions occupy the 6h sites, whereas the 4f sites are occupied in half by the Pb2+/Ca2+/Cd2+ ions and the other half by the Na+ ions. The observed frequencies in the Raman and infrared spectra are explained and discussed based on the factor group analysis and by comparison with similar apatites. The vibrational spectroscopy results are in good agreement with the X-ray diffraction measurements. The internal modes of (PO4)3− tetrahedra are assigned and corroborate well with the factor group analysis for the symmetry P63/m. We also investigated the thermal stability of these apatite materials by differential scanning calorimetry. [ABSTRACT FROM AUTHOR]

We report the crystal structure of Ba(CN3H4)2 as synthesized from liquid ammonia. Structure solution based on X‐ray diffraction data suffers from a severe pseudo‐tetragonal problem due to extreme scattering contrast, so the true monoclinic symmetry is detectable only from neutron powder diffraction patterns, and structure solution and refinement was greatly aided by density‐functional theory. The symmetry lowering is due to slight deviations of the guanidinate anion from the mirror plane in space group P4‾b2, a necessity of hydrogen bonding. At 300 K, barium guanidinate crystallizes in P21/c with a=6.26439(2) Å, b=16.58527(5) Å, c=6.25960(2) Å, and a monoclinic angle of β=90.000(1)°. To improve the data‐to‐parameter ratio, anisotropic displacement parameters from first‐principles theory were incorporated in the neutron refinement. Given the correct structural model, the positional parameters of the heavy atoms were also refinable from X‐ray diffraction of a twinned crystal. The two independent guanidinate anions adopt the all‐trans‐ and the anti‐shape. The Ba cation is coordinated by eight imino nitrogens in a square antiprism with Ba−N contacts between 2.81 and 3.04 Å. The IR and Raman spectra of barium guanidinate were compared with DFT‐calculated phonon spectra to identify the vibrational modes. All about that Ba: We report the oxidation‐controlled synthesis of barium guanidinate Ba(CN3H4)2 from liquid ammonia and discuss the crystal‐structure determination of the severely pseudo‐symmetrical monoclinic phase from high‐resolution neutron powder diffraction aided by first‐principles electronic‐structure theory. The infrared and Raman spectra have been assigned from first‐principles phonon calculations. [ABSTRACT FROM AUTHOR]

The plant cell wall is a dynamic network of several biopolymers and structural proteins including cellulose, pectin, hemicellulose and lignin. Cellulose is one of the main load bearing components of this complex, heterogeneous structure, and in this way, is an important regulator of cell wall growth and mechanics. Glucan chains of cellulose aggregate via hydrogen bonds and van der Waals forces to form long thread-like crystalline structures called cellulose microfibrils. The shape, size, and crystallinity of these microfibrils are important structural parameters that influence mechanical properties of the cell wall and these parameters are likely important determinants of cell wall digestibility for biofuel conversion. Cellulose–cellulose and cellulose-matrix interactions also contribute to the regulation of the mechanics and growth of the cell wall. As a consequence, much emphasis has been placed on extracting valuable structural details about cell wall components from several techniques, either individually or in combination, including diffraction/scattering, microscopy, and spectroscopy. In this review, we describe efforts to characterize the organization of cellulose in plant cell walls. X-ray scattering reveals the size and orientation of microfibrils; diffraction reveals unit lattice parameters and crystallinity. The presence of different cell wall components, their physical and chemical states, and their alignment and orientation have been identified by Infrared, Raman, Nuclear Magnetic Resonance, and Sum Frequency Generation spectroscopy. Direct visualization of cell wall components, their network-like structure, and interactions between different components has also been made possible through a host of microscopic imaging techniques including scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. This review highlights advantages and limitations of different analytical techniques for characterizing cellulose structure and its interaction with other wall polymers. We also delineate emerging opportunities for future developments of structural characterization tools and multi-modal analyses of cellulose and plant cell walls. Ultimately, elucidation of the structure of plant cell walls across multiple length scales will be imperative for establishing structure-property relationships to link cell wall structure to control of growth and mechanics. [ABSTRACT FROM AUTHOR]

We report the crystal structure of Ba(CN3H4)2 as synthesized from liquid ammonia. Structure solution based on X‐ray diffraction data suffers from a severe pseudo‐tetragonal problem due to extreme scattering contrast, so the true monoclinic symmetry is detectable only from neutron powder diffraction patterns, and structure solution and refinement was greatly aided by density‐functional theory. The symmetry lowering is due to slight deviations of the guanidinate anion from the mirror plane in space group P4‾b2, a necessity of hydrogen bonding. At 300 K, barium guanidinate crystallizes in P21/c with a=6.26439(2) Å, b=16.58527(5) Å, c=6.25960(2) Å, and a monoclinic angle of β=90.000(1)°. To improve the data‐to‐parameter ratio, anisotropic displacement parameters from first‐principles theory were incorporated in the neutron refinement. Given the correct structural model, the positional parameters of the heavy atoms were also refinable from X‐ray diffraction of a twinned crystal. The two independent guanidinate anions adopt the all‐trans‐ and the anti‐shape. The Ba cation is coordinated by eight imino nitrogens in a square antiprism with Ba−N contacts between 2.81 and 3.04 Å. The IR and Raman spectra of barium guanidinate were compared with DFT‐calculated phonon spectra to identify the vibrational modes. All about that Ba: We report the oxidation‐controlled synthesis of barium guanidinate Ba(CN3H4)2 from liquid ammonia and discuss the crystal‐structure determination of the severely pseudo‐symmetrical monoclinic phase from high‐resolution neutron powder diffraction aided by first‐principles electronic‐structure theory. The infrared and Raman spectra have been assigned from first‐principles phonon calculations. [ABSTRACT FROM AUTHOR]

Abstract Pure and potassium iodide (KI) doped hydroxyapatite (HAp) nanostructures were prepared through a facile microwave route. Field emission - SEM (FESEM) confirm low dimension nanorods (NRs) morphology of final products. The average dimension of NRs is may be in the range of 10–20 nm. Predominant single segment was approved by XRD and EDX analyses. Lattice constants, crystallite size, density of dislocations, strain and % of crystallinity were determined and the average crystallite size is observed in 9–16 nm range and degree of crystallinity is observed to be high viz. ~ 59% for 30% KI doped HAp. Vibrational studies were done through FT-IR and FT-Raman spectroscopy and confirm the phase of HAp. The catalytic activity of all samples is done in bioremediation of methylene blue using Stenotrophomonas maltophilia strain Kilany_MB. These results suggested that HAp and KI-HAp as a promising nano-catalyst in bioremediation of water from methylene blue. [ABSTRACT FROM AUTHOR]

The electrochemistry of TCNQF (2‐fluoro‐7,7,8,8‐tetracyanoquinodimethane) in acetonitrile (0.1 M Bu4NPF6) in the presence of either Co2+ or Ni2+ is reported. Cyclic voltammetry over an extensive range of potentials revealed that the reduction of TCNQF to either TCNQF1− or the TCNQF2− species provides a route for electrocrystallisation of the respective M(TCNQF)2(H2O)2 and M(TCNQF) materials on the electrode surface. These materials were independently prepared by addition of the corresponding metal salts to a solution of either TCNQF1− or TCNQF2− prepared by bulk electrolysis. Comprehensive characterisation of these solids by Infrared and Raman spectroscopy indicated that the M(TCNQF)2(H2O)2 complexes were similar to other transition metal complexes in the M(TCNQX)2(S)2 series where S=solvent (H2O or CH3OH) and X = H4 or F4. The M(TCNQF) materials containing the TCNQF2− anion were not stable in air, similar to the highly air‐sensitive TCNQ2− derivatives. Scanning Electron Microscopy (SEM) images of electrocrystallised samples of Ni(TCNQF)2(H2O)2 were rod‐like, whereas the Co(TCNQF)2(H2O)2 formed needles. Energy‐dispersive X‐ray spectroscopy (EDX) analysis of these samples together with elemental microanalysis and thermogravimetric analysis (TGA) supported the composition and stoichiometry. The solubility products (Ksp values) of M(TCNQF)2(H2O)2 materials were determined spectrophotometrically and voltammetrically in acetonitrile, where Ksp for Co(TCNQF)2(H2O)2 was 3.37×10−11 M3 (or 1.14×10−10 M3 in the presence of electrolyte, 0.1 M Bu4NPF6) and Ni(TCNQF)2(H2O)2 was 5.54×10−12 M3 (or 2.65×10−10 M3 in the presence of electrolyte, 0.1 M Bu4NPF6). The electrochemistry of TCNQF in acetonitrile containing either Co2+ or Ni2+ is reported. Cyclic voltammetry of the TCNQF0/1− and TCNQF1−/2− processes reveals a route for electrocrystallisation of either M(TCNQF)2(H2O)2 or M(TCNQF) on the electrode surface. Characterisation of these solids indicates a composition of M(TCNQF)2(H2O)2 (first reduction process) and M(TCNQF) (second reduction process). The solubility products of M(TCNQF)2(H2O)2 materials are also determined. [ABSTRACT FROM AUTHOR]

In this manuscript, we report a detailed physico-chemical comparison between the α- and β-polymorphs of the NaMnO2 compound, a promising material for application in positive electrodes for secondary aprotic sodium batteries. In particular, the structure and vibrational properties, as well as electrochemical performance in sodium batteries, are compared to highlight differences and similarities. We exploit both laboratory techniques (Raman spectroscopy, electrochemical methods) and synchrotron radiation experiments (Fast-Fourier Transform Infrared spectroscopy, and X-ray diffraction). Notably the vibrational spectra of these phases are here reported for the first time in the literature as well as the detailed structural analysis from diffraction data. DFT+U calculations predict both phases to have similar electronic features, with structural parameters consistent with the experimental counterparts. The experimental evidence of antisite defects in the beta-phase between sodium and manganese ions is noticeable. Both polymorphs have been also tested in aprotic batteries by comparing the impact of different liquid electrolytes on the ability to de-intercalated/intercalate sodium ions. Overall, the monoclinic α-NaMnO2 shows larger reversible capacity exceeding 175 mAhg−1 at 10 mAg−1.

• Hybrid supramolecular nitrate of 2,6-diaminopyridine. • Slow evaporation at room temperature synthesis method. • Theoretical (TDDFT) investigations. The supramolecularstructure of the new hybrid material with formula [C 5 H 8 N 3 ]NO 3 wasdetermined by singlecrystal X-Ray diffraction. It crystallizes in the monoclinic system, space groupP2 1.The stability of the supramolecularstructure wasensured by hydrogen bonding contacts N − H ⋯ O and by π ⋯ π interactions between the aromatic rings of 2,6-diaminopyridinemolecules.The Infrared and Ramanspectra were recorded, confirming the existence of vibrational modes thatcorrespond to the organic and inorganic groups. Thethermal study (TGA) proved the stability of the crystal up to 180 °C.The Hirshfeldanalysisresultsshow that in all potentialmolecular contacts, the O ⋯ H/H ⋯ Oconstitutes the most important interaction in the crystal (41.3%).Experimental (UV–Visible absorption) and theoretical (TDDFT) investigations of the opticalproperties of the compound confirmeditssemiconductingproperties by revealing a direct optical bandgap at 4.8 eV.Finally, photoluminescence measurementindicatesthat the synthesizedmaterialmanifests luminescence property in itssolid state. [ABSTRACT FROM AUTHOR]

The iodine complex formation behavior of a series of vinyl alcohol-vinyl acetate copolymers (P(VA-co-VAc), -[CH 2 CH(OH)+CH 2 CH(OCOCH 3)] n -) has been studied systematically on the basis of X-ray diffraction and IR/Raman spectroscopic data. The VA segments in the copolymers were found to start to crystallize for the first time when the sequential segmental length is beyond the critical sequential length of 3–4 VA monomeric units. Below this critical length, the OH units on VA segments exist as isolated groups or as being connected with O=C bonds of VAc segments. The latter type of hydrogen bonds, –C=O ⋯ HO-, was found to be formed in the copolymers of a wide range of VA content of 30–90 mol%. The immersion of these VA-VAc copolymers into the iodine solution gave the crystalline iodine complexes. In the VA range of 0–40%, the PVAc-I 5 - complex (β form) is formed mainly. Once when the VA content is beyond the critical sequential length, the PVA-I 3 - complex of form II starts to be created and develops into the larger and regular crystalline complex in addition to the PVAc-iodine complex. [Display omitted] • Structural evolution behavior has been clarified for a series of VA-VAc copolymers and their iodine-complexes. • Critical sequential length of VA units was evaluated, which is necessary for crystallization of P(VA-co-VAc) copolymers. • Characteristic iodine complex structure created in the VA and VAc monomer sequences have been clarified by X-ray analysis. [ABSTRACT FROM AUTHOR]

We explore the structure of two ionic liquids based on the choline cation and the monoanion of the maleic acid. We consider two isomers of the anion (H-maleate, the cis-isomer and H-fumarate, the trans-isomer) having different physical chemical properties. H-maleate assumes a closed structure and forms a strong intramolecular hydrogen bond whereas H-fumarate has an open structure. X-ray diffraction, infrared and Raman spectroscopy and molecular dynamics have been used to provide a reliable picture of the interactions which characterize the structure of the fluids. All calculations indicate that the choline cation prefers to connect mainly to the carboxylate group through OH⋯O interactions in both the compounds and orient the charged head N(CH3)3+ toward the negative portion of the anion. However, the different structure of the two anions affects the distribution of the ionic components in the fluid. The trans conformation of H-fumarate allows further interactions between anions through COOH and CO2− groups whereas intramolecular hydrogen bonding in H-maleate prevents this association. Our theoretical findings have been validated by comparing them with experimental X-ray data and infrared and Raman spectra.

The 3:2 Charge Transfer (CT) co-crystal (Perylene)3(TCNQF1)2 is grown by the Physical Vapor Transport (PVT) method, and characterized structurally and spectroscopically. Infrared analysis of the charge sensitive modes reveals a low degree of charge transfer (less than 0.1) between donor and acceptor molecules. The crystal is isostructural to the other 3:2 CT crystals formed by Perylene with TCNQF2 and TCNQF4, whereas such stoichiometry and packing is not known for the CT crystals with non-fluorinated TCNQ. The analysis of the isostructural family of 3:2 Perylene−TCNQFx (x = 1,2,4) co-crystal put in evidence the role of weak F…HC bonding in stabilizing this type of structure

The reaction of p‐benzoquinone in the binary superacidic systems XF/MF5 (M = As, Sb; X = H, D) leads to the formation of the corresponding salts [OC6H4(OX)][MF6] (M = As, Sb; X = H, D). Threefold excess of Lewis acid in relation to p‐benzoquinone is required to form these salts quantitatively. The salts are characterized by infrared spectroscopy and in the case of [OC6H4(OH)][SbF6] (2) by a single‐crystal X‐ray structure analysis, according to which it is more correctly described as a double hemi‐protonated salt of p‐benzoquinone. The salt crystallizes in the triclinic space group P1 with one formula unit per unit cell. In the solid state the cations are arranged in chains, linked via O···(H)···O bonds. The vibrational spectra were compared to quantum chemical calculations of the cation [OC6H4(OH)]+. [ABSTRACT FROM AUTHOR]

The conformational properties and the molecular structure of dichlorophosphoryl isocyanate, Cl2P(O)NCO, were studied by combining vibrational spectroscopy (IR and Raman), gas‐phase electron diffraction (GED), X‐ray crystallography (XRD), and quantum‐chemical calculations. Computationally, two conformers of Cs symmetry with the P=O bond being in syn or anti configuration relative to the NCO group are predicted to be close in energy (ca. 2 kJ mol–1). Experimentally, both gas‐phase and matrix‐isolation IR spectra of Cl2P(O)NCO suggest the presence of a single conformer, which was determined to be the energetically more favorable syn‐conformer. This was also found to exist in the solid state by low‐temperature XRD. However, the molecule in the solid state is significantly distorted from ideal Cs symmetry with an O–P–N–C dihedral angle of 38.1(1)° due to intermolecular C···O contacts [2.881(4) Å]. In the gas phase, the GED analysis suggests that the molecule exists predominantly as syn‐conformer but with dynamic behavior about the two minimum structures (syn and anti). [ABSTRACT FROM AUTHOR]

Oxalic acid forms in superacidic solutions HF/MF5 (M = As, Sb) its corresponding mono‐ and diprotonated salts [HOOCC(OH)2][MF6] and [(HO)2CC(OH)2][MF6]2 (M = As, Sb). The number of protonations is strongly dependent on the stoichiometric ratio of the Lewis acid with regard to oxalic acid. Mono‐ and diprotonated salts were characterized by vibrational spectroscopy and in the case of [HOOCC(OH)2][AsF6] (1) and [(HO)2CC(OH)2][SbF6]2 (4) by a single‐crystal X‐ray structure analysis. The salts crystallize in the monoclinic space groups P21/c and P21/n with eight, respectively four, formula units per unit cell. The vibrational spectra were compared to quantum chemical calculations of the cations [HOOCC(OH)2]+ and [(OH)2CC(OH)2]2+⋅4HF. In addition to this, an MEP analysis together with the NPA charges of [(OH)2CC(OH)2]2+, [(OH)2CC(OH)2]2+⋅6HF and oxalic acid were calculated to locate the positive charge. The protonation of oxalic acid does not lead to a remarkable change of the C‐C bond length, which is discussed for the entire series of the oxalic skeleton, starting with the dianion and ending with the tetrahydroxy dication. Tetrahydroxydicarbenium salts, containing two vicinal positive charges at the carbon atoms, were isolated for the first time. Mono‐ and diprotonated oxalic acid are characterized by vibrational spectroscopy as well as single‐crystal analyses. Surprisingly, the protonation of oxalic acid does not lead to a significant change of the CC bond length. [ABSTRACT FROM AUTHOR]

The compound 3′‐(1‐benzyl‐5‐methyl‐1H‐1,2,3‐triazole‐4‐carbonyl)‐1′‐methyl‐4′‐(3‐nitrophenyl)‐2H‐spiro[acenaphthylene‐1,2′‐pyrrolidin]‐2‐one [BTNANP] was synthesized and characterized by (FT‐IR/FT‐Raman), NMR (1H and 13C), UV‐Visible, Fluorescence and XRD studies. The molecular geometry was optimized using density functional theory (DFT/B3LYP) method with 6–311G (d,p) basis set in the ground state and compared with the experimental data. The entire vibrational assignments of wave numbers were made on the basis of potential energy distribution (PED) by VEDA 4 programme. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analysed using the Natural Bond Orbital (NBO) analysis. It was also confirmed by the assignments of UV‐Vis spectrum. The fluorescence spectrum confirms that the title compound is a red‐light emitting material. In addition, NLO, MEP, Mulliken atomic charges, thermodynamic properties, HOMO and LUMO energy gap were theoretically predicted. The global chemical reactivity descriptors were calculated for BTNANP and used to predict their relative stability and reactivity. The antimicrobial activity of the compound was also tested against the selected bacterial and fungal pathogens. The molecular docking studies concede that the title compound may exhibit inhibition activity against topoisomerase II and lanosterol 14 α‐demethylase. The novel compound 3′‐(1‐benzyl‐5‐methyl‐1H‐1,2,3‐triazole‐4‐carbonyl)‐1′‐methyl‐4′‐(3‐nitrophenyl)‐2H‐spiro[acenaphthylene‐1,2′‐pyrrolidine]‐2‐one [BTNANP] was synthesized. The spectral, electronic and thermal properties and the antimicrobial activity of the compound were analysed. A comparative account was made between experimental and theoretical data for (FT‐IR/FT‐Raman), NMR (1H and 13C), UV‐Visible and XRD studies. Molecular docking study has also been carried out against 2XCT and 3LD6 to investigate the biological activity of the compound. [ABSTRACT FROM AUTHOR]

Single crystals of bis[1-(diaminomethylene)thiouron-1-ium] naphthalene-1,5-disulfonate ( 1 ) are grown using growth solution technique. The compound crystallizes in the centrosymmetric C2/c space group of the monoclinic system with four molecules per unit cell. The arrangement of oppositely charged units, i.e. 1-(diaminomethylene)thiouron-1-ium cations and naphthalene-1,5-disulfonate anions in the crystal is mainly determined by the ionic and the N H ⋯ O hydrogen bonding interactions. Hirshfeld surface and the analysis of 2D fingerprint plots are illustrating both qualitatively and quantitatively interactions governing the supramolecular arrangement. The compound was also characterized by FT-IR and Raman spectroscopies. The vibrational assignment of the characteristic bands of the functional groups have been supported by the isotopic frequency shift. [ABSTRACT FROM AUTHOR]

Abstract: The syntheses of [OC(COX)3][MF6] and [(COX)4][MF6]2⋅2 HF were carried out in superacidic media XF/MF5 (M=As, Sb; X=H, D). The degree of protonation is highly dependent on the stoichiometric ratio of the Lewis acid with regard to squaric acid. The salts of diprotonated squaric acid were characterized by Raman spectroscopy and, in the case of [(COH)4][MF6]2⋅2 HF (M=As, Sb), by single‐crystal X‐ray structure analyses. [(COH)4][AsF6] crystallizes in the monoclinic space group P21/n with two formula units per unit cell. Analysis of the vibrational spectra was achieved with the support of quantum chemical calculations of the cation [(COH)4]2+⋅4 HF on the PBE1PBE/6‐311G++(3df,3pd) level of theory. Furthermore, a salt of monoprotonated squaric acid, [OC(COH)3][AsF6], was characterized by a single‐crystal X‐ray structure analysis. It crystallizes in the monoclinic space group P21/n with four formula units per unit cell. The protonation of squaric acid leads to a change of the carbon skeleton, which is discussed for the entire series, starting with the dianion of squaric acid and ending with the tetrahydroxy dication. [ABSTRACT FROM AUTHOR]

According to literature data the two crystals are known: guanidinium m-nitrobenzoate and guanidinium p -nitrobenzoate. Both compounds belong to noncetrosymmetric crystallographic systems are consider as second order generators in nonlinear optic (NLO). For each of these crystals the detailed crystallographic, theoretical calculations and vibrational studies were performed. It is interesting that nitrobenzoic acid create tree variety of compounds ((2) ortho-, (3) meta- and (4) para-) what any data for third member of guanidinium nitrobenzoate crystal were not known. The guanidinium o -nitrobenzoate hydrate crystal was synthesized first time. The performed X-ray crystallographic study shown that crystal belongs to space group without macroscopic symmetry center. Additionally, the vibrational spectra (intensities, frequencies and PED analysis) of investigated compound are presented. These results are compared with theoretical calculations for equilibrium geometry and vibrational properties. Furthermore, the results of the theoretical approach include HOMO and LUMO energies and first order hyperpolarizability were obtained, also. On the basis of these data the crystal was classified as second order generator. All obtained results are compared with previous literature data of guanidinium m-nitrobenzoate and guanidinium p -nitrobenzoate compounds. Surprisingly, each of examined crystal belongs to different crystallographic system and shows different vibrational properties. [ABSTRACT FROM AUTHOR]

The results of the experimental study of glass of the xFe2O3-(100-x)[40ZnO. 60B2O3] composition in which the content of iron oxide varies from 0 to 10 mol % are presented. The regularities of the glass structure change in the short- and intermediate-range order structures are considered based on the data of infrared spectroscopy and Raman spectroscopy. The valence and coordination state of iron in a glass matrix is studied by Mössbauer spectroscopy. [ABSTRACT FROM AUTHOR]