Thermo Differential Analysis Research Articles

Thermolysis of Cs9MO4 (M = In, Sc): Synthesis, Crystal Structure, Chemical Bonding, and Reactivity of the Subvalent Oxidometalates Cs7MO4 (M = In, Sc).

The cesium-poor alkali-metal suboxidometalates Cs7MO4 (M = In, Sc) were prepared from the respective cesium-rich suboxidometalates Cs9MO4 by thermolysis in a dynamic vacuum at temperatures below 150 °C. They crystallize in a new structure type, comprising isolated tetrahedral oxidometalate anions [MO4]5- immersed in a matrix of metallic cesium atoms. This structural separation into alternating ionic and metallic building units is typical for subvalent compounds. Cs7InO4 and Cs7ScO4 are isotypic and form mixed crystals Cs7(In1-xScx)O4 with statistic distribution of In and Sc atoms. All compounds were characterized by single crystal and powder X-ray diffraction. Calculations of the electronic structure with DFT methods corroborate the coexistence of anionic entities within a metallic matrix and give evidence of the subvalent nature of cesium atoms. Overall metallic behavior is a consequence of the equal volume fractions of metallic and ionic regions, allowing for percolation of the conduction electrons throughout the crystal volume. Differential thermoanalysis was employed to gain insight into the chemical conversion processes during the thermolysis reaction. The thermolytic decomposition of Cs9MO4 is a multistep process with, in some instances, reversible amorphization and recrystallization steps. Finally, the formation of ionic compounds is observed. The full decomposition of Cs9ScO4 yields the two new oxidoscandates Cs14Sc4O13 and Cs17Sc5O15 with tetrahedral [ScO4] units connected to chain fragments and the indium compound yields cesium oxidoindates with low-condensed [InO4] building units. The cesium-poor suboxidometalates Cs7MO4 themselves can serve as starting materials for the synthesis of further, new suboxidometalates, as they show a unique reactivity toward metals.

Syntheses and properties of seven 3,4-dichlorobenzoate-based zinc-rare earth heterometallic complexes containing a field-induced Zn(II)-Dy(III)-Dy(III)-Zn(II) single-molecule magnet

Under solvothermal conditions of CH3CH2OH and H2O, a series of 3d-4f heterometallic complexes [Ln2Zn2(3,4-DCB)10(2,2′-bpy)2] [Ln = Sm (1), Eu (2), Gd (3), Tb (4), Dy (5), Er (6) and Yb (7), 3,4-DCB = 3,4-dichlorobenzoic acid, 2,2′-bpy = 2,2′-bipyridine] were synthesized by the reactions of Ln(NO3)3·6H2O, Zn(NO3)2·6H2O, 3,4-HDCB, 2,2′-bpy and NaOH. These complexes were characterized by single crystal X-ray diffraction, powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA) and differential thermo analysis (DTA). Complexes 1–7 show two types of different zero-dimensional (0D) structures although they have the same molecular formula. Complexes 1–5 are isomorphic, and complexes 6 and 7 are isomorphic. In 1–7, linear tetranuclear clusters are formed from 3,4-DCB connecting Ln(III) and Zn(II). They can be expanded into one-dimensional (1D) supramolecular chains or two-dimensional (2D) supramolecular layers by the intermolecular π–π interactions. The photoluminescent properties of 1, 2, 4 and 5 and the magnetic properties of 3–7 were studied in detail. Complex 5 exhibits an obvious field-induced single-molecule magnet behavior with a Ueff value of approximately 24 K.

Synthesis, crystal structure and thermal properties of catena-poly[[bis-(4-methyl-pyridine)-nickel(II)]-di-μ-thio-cyanato], which shows an alternating all-trans and cis-cis-trans-coordination of the NiS2Np 2Nt 2 octa-hedra (p = 4-methyl-pyridine, t = thio-cyanate).

The title compound, [Ni(NCS)2(C6H7N)2] n , was prepared by the reaction of Ni(NCS)2 with 4-methyl-pyridine in water. Its asymmetric unit consists of two crystallographically independent NiII cations, of which one is located on a twofold rotational axis whereas the second occupies a center of inversion, two independent thio-cyanate anions and two independent 4-methyl-pyridine co-ligands in general positions. Each NiII cation is octa-hedrally coordinated by two 4-methyl-pyridine coligands as well as two N- and two S-bonded thio-cyanate anions. One of the cations shows an all-trans, the other a cis-cis-trans configuration. The metal centers are linked by pairs of μ-1,3-bridging thio-cyanate anions into [101] chains. X-ray powder diffraction shows that a pure crystalline phase has been obtained and thermogravimetry coupled to differential thermoanalysis reveals that the title compound loses half of the 4-methyl-pyridine coligands and transforms into Ni(NCS)2(C6H7N). Nearly pure samples of this compound can be obtained by thermal annealing and a Rietveld refinement demonstrated that it is isotypic to its recently reported Cd analog [Neumann et al., (2020 ▸). CrystEngComm. 22, 184-194] In its crystal structure, the metal cations are linked by one μ-1,3(N,S)- and one μ-1,3,3(N,S,S)-bridging thio-cyanate anion into single chains that condense via the μ-1,3,3(N,S,S)-bridging anionic ligands into double chains.

Synthesis, crystal structure and thermal properties of a new polymorphic modification of diisothiocyanatotetrakis(4-methylpyridine)cobalt(II)

The title compound, [Co(NCS)2(C6H7N)4] or Co(NCS)2(4-methylpyridine)4, was prepared by the reaction of Co(NCS)2 with 4-methylpyridine in water and is isotypic to one of the polymorphs of Ni(NCS)2(4-methylpyridine)4 [Kerr & Williams (1977). Acta Cryst. B33, 3589–3592 and Soldatov et al. (2004). Cryst. Growth Des. 4, 1185–1194]. Comparison of the experimental X-ray powder pattern with that calculated from the single-crystal data proves that a pure phase has been obtained. The asymmetric unit consists of one CoII cation, two crystallographically independent thiocyanate anions and four independent 4-methylpyridine ligands, all located in general positions. The CoII cations are sixfold coordinated to two terminally N-bonded thiocyanate anions and four 4-methylpyridine coligands within slightly distorted octahedra. Between the complexes, a number of weak C—H...N and C—H...S contacts are found. This structure represent a polymorphic modification of Co(NCS)2(4-methylpyridine)4 already reported in the CCD [Harris et al. (2003). NASA Technical Reports, 211890]. In contrast to this form, the crystal structure of the new polymorph shows a denser packing, indicating that it is thermodynamically stable at least at low temperatures. Thermogravimetric and differential thermoanalysis reveal that the title compound starts to decomposes at about 100°C and that the coligands are removed in separate steps without any sign of a polymorphic transition before decomposition.

Synthesis and crystal structure of diisothiocyanatotetrakis(4-methylpyridine N-oxide)cobalt(II) and diisothiocyanatotris(4-methylpyridine N-oxide)cobalt(II) showing two different metal coordination polyhedra

The reaction of Co(NCS)2 with 4-methylpyridine N-oxide (C6H7NO) leads to the formation of two compounds, namely, tetrakis(4-methylpyridine N-oxide-κO)bis(thiocyanato-κN)cobalt(II), [Co(NCS)2(C6H7NO)4] (1), and tris(4-methylpyridine N-oxide-κO)bis(thiocyanato-κN)cobalt(II), [Co(NCS)2(C6H7NO)3] (2). The asymmetric unit of 1 consists of one CoII cation located on a centre of inversion, as well as one thiocyanate anion and two 4-methylpyridine N-oxide coligands in general positions. The CoII cations are octahedrally coordinated by two terminal N-bonding thiocyanate anions in trans positions and four 4-methylpyridine N-oxide ligands. In the extended structure, these complexes are linked by C—H...O and C—H...S interactions. In compound 2, two crystallographically independent complexes are present, which occupy general positions. In each of these complexes, the CoII cations are coordinated in a trigonal–bipyramidal manner by two terminal N-bonding thiocyanate anions in axial positions and by three 4-methylpyridine N-oxide ligands in equatorial positions. In the crystal, these complex molecules are linked by C—H...S interactions. For compound 2, a nonmerohedral twin refinement was performed. Powder X-ray diffraction (PXRD) reveals that 2 was nearly obtained as a pure phase, which is not possible for compound 1. Differential thermoanalysis and thermogravimetry data (DTA–TG) show that compound 2 start to decompose at about 518 K.

Synthesis, crystal structure and properties of poly[(μ-2-methyl-pyridine N-oxide-κ2O:O)bis-(μ-thio-cyanato-κ2N:S)cobalt(II)

The title compound, [Co(NCS)2(C6H7NO)]n or Co(NCS)2(2-methyl-pyridine N-oxide), was prepared by the reaction of Co(NCS)2 and 2-methyl-pyridine N-oxide in methanol. All crystals obtained by this procedure show reticular pseudo-merohedric twinning, but after recrystallization, one crystal was found that had a minor component with only a very few overlapping reflections. The asymmetric unit consists of one CoII cation, two thio-cyanate anions and one 2-methyl-pyridine N-oxide coligand in general positions. The CoII cations are octa-hedrally coordinated by two O-bonding 2-methyl-pyridine N-oxide ligands, as well as two S- and two N-bonding thio-cyanate anions, and are connected via μ-1,3(N,S)-bridging thio-cyanate anions into chains that are linked by μ-1,1(O,O) bridging coligands into layers. No pronounced directional inter-molecular inter-actions are observed between the layers. The 2-methyl-pyridine coligand is disordered over two orientations and was refined using a split model with restraints. Powder X-ray diffraction (PXRD) indicates that a pure sample was obtained and IR spectroscopy confirms that bridging thio-cyanate anions are present. Thermogravimetry and differential thermoanalysis (TG-DTA) shows one poorly resolved mass loss in the TG curve that is accompanied by an exothermic and an endothermic signal in the DTA curve, which indicate the decomposition of the 2-methyl-pyridine N-oxide coligands.

Synthesis, structure, photoluminescence and magnetism of a series of cobalt‐lanthanide heterometallic complexes originated from 2,3‐dichlorobenzoate and 1,10‐phenanthroline

AbstractA series of 3d–4f heterometallic complexes, namely [Ln2Co2(2,3‐DCB)10(phen)2] [Ln=Nd (1), Sm (2), Eu (3), Gd (4), Tb (5), Dy (6), Er (7)], were obtained through the self‐assembly reactions of Ln(NO3)3 ⋅ nH2O, Co(NO3)2 ⋅ 6H2O, 2,3‐dichlorobenzoic acid (2,3‐HDCB), NaOH and 1,10‐phenanthroline (phen) under solvothermal conditions. Their crystal structures were determined by single‐crystal X‐ray diffraction. They were also characterized by elemental analysis, FT‐IR, powder X‐ray diffraction (PXRD) and thermogravimetric analysis (TGA) and differential thermoanalysis (DTA). These seven complexes have the same molecular formula but different crystal structures. Complexes 1–3, 4 and 5 as well as 6 and 7 are crystallographically isomorphous, respectively. They all exhibit zero‐dimensional (0D) linear tetranuclear cluster structures. These 0D linear tetranuclear clusters can be further connected into a two‐dimensional (2D) supramolecular network via the extensive intermolecular π–π interactions between 2,3‐DCB and phen. The photoluminescent properties of 3, 5 and 6 and the magnetic properties of 1–2 and 4–7 were investigated. Complex 6 shows a slow magnetic relaxation behavior.

Synthesis, crystal structure and properties of chlorido-tetra-kis-(pyridine-3-carbo-nitrile)-thio-cyanato-iron(II).

Reaction of FeCl2·4H2O with KSCN and 3-cyano-pyridine (pyridine-3-carbo-nitrile) in ethanol accidentally leads to the formation of single crystals of Fe(NCS)(Cl)(3-cyano-pyridine)4 or [FeCl(NCS)(C6H4N2)4]. The asymmetric unit of this compound consists of one FeII cation, one chloride and one thio-cyanate anion that are located on a fourfold rotation axis as well as of one 3-cyano-pyridine coligand in a general position. The FeII cations are sixfold coordinated by one chloride anion and one terminally N-bonding thio-cyanate anion in trans-positions and four 3-cyano-pyridine coligands that coordinate via the pyridine N atom to the FeII cations. The complexes are arranged in columns with the chloride anions, with the thio-cyanate anions always oriented in the same direction, which shows the non-centrosymmetry of this structure. No pronounced inter-molecular inter-actions are observed between the complexes. Initially, FeCl2 and KSCN were reacted in a 1:2 ratio, which lead to a sample that contains the title compound as the major phase together with a small amount of an unknown crystalline phase, as proven by powder X-ray diffraction (PXRD). If FeCl2 and KSCN is reacted in a 1:1 ratio, the title compound is obtained as a nearly pure phase. IR investigations reveal that the CN stretching vibration for the thio-cyanate anion is observed at 2074 cm-1, and that of the cyano group at 2238 cm-1, which also proves that the anionic ligands are only terminally bonded and that the cyano group is not involved in the metal coordination. Measurements with thermogravimetry and differential thermoanalysis reveal that the title compound decomposes at 169°C when heated at a rate of 4°C min-1 and that the 3-cyano-pyridine ligands are emitted in two separate poorly resolved steps. After the first step, an inter-mediate compound with the composition Fe(NCS)(Cl)(3-cyano-pyridine)2 of unknown structure is formed, for which the CN stretching vibration of the thio-cyanate anion is observed at 2025 cm-1, whereas the CN stretching vibration of the cyano group remain constant. This strongly indicates that the FeII cations are linked by μ-1,3-bridg-ing thio-cyanate anions into chains or layers.

Synthesis, crystal structure and properties of tetra-kis-(pyridine-3-carbo-nitrile)-dithio-cyanatoiron(II) and of diaqua-bis-(pyridine-3-carbo-nitrile)-di-thio-cyanatoiron(II) pyridine-3-carbo-nitrile monosolvate.

The reaction of iron thio-cyanate with 3-cyano-pyridine (C6H4N2) leads to the formation of two compounds with the composition [Fe(NCS)2(C6H4N2)4] (1) and [Fe(NCS)2(C6H4N2)2(H2O)2]·2C6H4N2 (2). The asymmetric unit of 1 consists of one iron cation, two thio-cyanate anions and four 3-cyano-pyridine ligands in general positions. The iron cation is octa-hedrally coordinated by two N-bonded thio-cyanate anions and four 3-cyano-pyridine ligands. The complexes are arranged in columns along the crystallographic c-axis direction and are linked by weak C-H⋯N inter-actions. In 2, the asymmetric unit consists of one iron cation on a center of inversion as well as one thio-cyanate anion, one 3-cyano-pyridine ligand, one water ligand and one 3-cyano-pyridine solvate mol-ecule in general positions. The iron cation is octa-hedrally coordinated by two N-bonded thio-cyanate anions, two cyano-pyridine ligands and two water ligands. O-H⋯N and C-H⋯S hydrogen bonding is observed between the water ligands and the solvent 3-cyano-pyridine mol-ecules. In the crystal structure, alternating layers of the iron complexes and the solvated 3-cyano-pyridine mol-ecules are observed. Powder X-ray (PXRD) investigations reveal that both compounds were obtained as pure phases and from IR spectroscopic measurements conclusions on the coordination mode of the thio-canate anions and the cyano-group were made. Thermogravimetric (TG) and differential thermoanalysis (DTA) of 1 indicate the formation of a compound with the composition {[Fe(NCS)2]3(C6H4N2)4}n that is isotypic to the corresponding Cd compound already reported in the literature. TG/DTA of 2 show several mass losses. The first mass loss corresponds to the removal of the two water ligands leading to the formation of 1, which transforms into {[Fe(NCS)2]3(C6H4N2)4}n, upon further heating.

Synthesis, crystal structure and thermal properties of poly[[μ-1,2-bis-(pyridin-4-yl)ethene-κ2N:N'-μ-bromido-copper(I)] 1,2-bis-(pyridin-4-yl)ethene 0.25-solvate

The reaction of copper(I) bromide with 1,2-bis-(pyridin-4-yl)ethene in aceto-nitrile leads to the formation of the title compound, {[CuBr(C12H10N2)]·0.25C12H10N2}n or CuBr(4-bpe)·0.25(4-bpe) [4-bpe = 1,2-bis-(pyridin-4-yl)ethene]. The asymmetric unit consists of one copper(I) cation and one bromide anion in general positions as well as two crystallographically independent half 4-bpe ligands and a quarter of a disordered 4-bpe solvate mol-ecule that are completed by centers of inversion. The copper(I) cations are tetra-hededrally coordinated as CuBr2N2 and linked by pairs of μ-1,1-bridging bromide anions into centrosymmetric dinuclear units that are further connected into layers by the 4-bpe coligands. Between the layers, inter-layer C-H⋯Br hydrogen bonding is observed. The layers are arranged in such a way that cavities are formed in which the disordered 4-bpe solvate mol-ecules are located. Powder X-ray (PXRD) investigations reveal that a pure sample has been obtained. Thermogravimetric (TG) and differential thermoanalysis (DTA) measurements show two mass losses that are accompanied by endothermic events in the DTA curve. The first mass loss correspond to the removal of 0.75 4-bpe mol-ecules, leading to the formation of (CuBr)2(4-bpe), already reported in the literature as proven by PXRD.

Synthesis, crystal structure and reactivity of bis-(μ-2-methyl-pyridine N-oxide-κ2O:O)bis-[di-bromido-(2-methyl-pyridine N-oxide-κO)cobalt(II)] butanol monosolvate.

Reaction of CoBr2 with 2-methyl-pyridine N-oxide in n-butanol leads to the formation of the title compound, [CoBr2]2(2-methyl-pyridine N-oxide)4·n-butanol or [Co2Br4(C6H7NO)4]·C4H10O. The asymmetric unit of the title compound consists of one CoII cation as well as two bromide anions and two 2-methyl-pyridine N-oxide coligands in general positions and one n-butanol mol-ecule that is disordered around a center of inversion. The CoII cations are fivefold coordinated by two bromide anions and one terminal as well as two bridging 2-methyl-pyridine N-oxide and linked by two symmetry-related μ-1,1(O,O) 2-methyl-pyridine N-oxide coligands into dinuclear units that are located on centers of inversion. In the crystal structure, the dinuclear units are also connected via pairs of C-H⋯Br hydrogen bonds into chains that elongate in the b-axis direction. The n-butanol mol-ecules are located between the chains and are linked via O-H⋯Br hydrogen bonds each to one chain. Powder X-ray diffraction (PXRD) measurements reveal that a pure phase has been obtained. Measurements using thermogravimetry and differential thermoanalysis shows one mass loss up to 523 K, in which the n-butanol mol-ecules are removed. PXRD measurements of the residue obtained after n-butanol removal shows that a completely different crystalline phase has been obtained and IR investigations indicate significant structural changes in the Co coordination.

Synthesis, crystal structure and thermal behavior of tetra-kis-(3-cyano-pyridine N-oxide-κO)bis-(thio-cyanato-κN)cobalt(II), which shows strong pseudo-symmetry.

The title compound, [Co(SCN)2(C6H4N2O)4], was prepared by the reaction of cobalt(II)thio-cyanate with 3-cyano-pyridine N-oxide in ethanol. In the crystal, the cobalt(II) cations are octa-hedrally coordinated by two terminal N-bonded thio-cyanate anions and four O-bonded 3-cyano-pyridine N-oxide coligands, forming discrete complexes that are located on centers of inversion, hence forming trans-CoN2O4 octa-hedra. The structure refinement was performed in the monoclinic space group P21/n, for which a potential lattice translation and new symmetry elements with a fit of 100% is suggested. The structure can easily be refined in the space group I2/m, where the complexes have 2/m symmetry. However, nearly all of the reflections that violate the centering are observed with significant intensity and the refinement in P21/n leads to significantly lower R(F) values (0.027 versus 0.033). Moreover, in I2/m much larger components of the anisotropic displacement parameters are observed and therefore, the crystal structure is presented in the primitive unit cell. IR investigations confirm that the anionic ligands are only terminally bonded and that the cyano group is not involved in the metal coordination. PXRD investigations show that a pure crystalline phase has been obtained and measurements using simultaneously thermogravimetry and differential thermoanalysis reveal that the compound decomposes in an exothermic reaction upon heating, without the formation of a coligand-deficient inter-mediate phase.

Syntheses, crystal structures and thermal properties of catena-poly[cadmium(II)-di-μ-bromido-μ-pyridazine-κ2 N 1:N 2] and catena-poly[cadmium(II)-di-μ-iodido-μ-pyridazine-κ2 N 1:N 2

The reactions of cadmium bromide and cadmium iodide with pyridazine (C4H4N2) in ethanol under solvothermal conditions led to the formation of crystals of [CdBr2(pyridazine)] n (1) and [CdI2(pyridazine)] n (2), which were characterized by single-crystal X-ray diffraction. The asymmetric units of both compounds consist of a cadmium cation located on the inter-section point of a twofold screw axis and a mirror plane (2/m), a halide anion that is located on a mirror plane and a pyridazine ligand, with all atoms occupying Wyckoff position 4e (mm2). These compounds are isotypic and consist of cadmium cations that are octa-hedrally coordinated by four halide anions and two pyridazine ligands and are linked into [100] chains by pairs of μ-1,1-bridging halide anions and bridging pyridazine ligands. In the crystals, the pyridazine ligands of neighboring chains are stacked onto each other, indicating π-π inter-actions. Larger amounts of pure samples can also be obtained by stirring at room-temperature, as proven by powder X-ray diffraction. Measurements using thermogravimetry and differential thermoanalysis (TG-DTA) reveal that upon heating all the pyridiazine ligands are removed in one step, which leads to the formation of CdBr2 or CdI2.

Synthesis, crystal structure and properties of bis-(iso-seleno-cyanato-κN)tetra-kis-(4-meth-oxy-pyridine-κN)cobalt(II).

Reaction of CoCl2·6H2O with KNCSe and 4-meth-oxy-pyridine in water led to the formation of the title compound, [Co(NCSe)2(C6H7NO)4] or Co(NCSe)2(4-meth-oxy-pyridine)2, which was characterized by single-crystal X-ray diffraction. Its asymmetric unit consists of one crystallographically independent Co cation, two seleno-cyanate anions and four 4-meth-oxy-pyridine coligands in general positions. In the crystal structure, the cobalt cations are sixfold coordinated by two terminal N-bonded seleno-cyanate anions and four 4-meth-oxy-pyridine coligands within a slightly distorted octa-hedral coordination. Between the complexes, weak C-H⋯Se inter-actions are found. IR spectroscopic investigations revealed that the CN stretching vibration of the anionic ligands is observed at 2068 cm-1, which is in agreement with the presence of only terminally coordinated seleno-cyanate anions. PXRD measurements prove that a pure compound was obtained. Differential thermoanalysis coupled to thermogravimetry (DTA-TG) at different heating rates shows that the TG curves are poorly resolved. PXRD measurements of the residue obtained by a TG measurement prove that an amorphous compound was obtained.

X-Ray Crystallography, Spectral Analysis, DFT Studies, and Molecular Docking of (C9H15N3)[CdCl4] Hybrid Material against Methicillin-Resistant Staphylococcus aureus (MRSA)

The one dimensional polymer complex (C9H15N3)[CdCl4], was synthesized and characterized by X-ray crystallography, FT-IR vibrational, and thermal analysis, UV–Visible and photoluminescence (PL) spectroscopic investigations. The crystal structure crystallizes in the monoclinic space group C2/c with Z = 4. The experimental geometric data of the crystalline molecule and the results of density functional theory (DFT) generated utilizing computational methods at DFT/ωB97XD and DFT/B3LYP-D3/Gen/6-311++G(d, p)//LanL2DZ levels of theory were compared. Significantly, in order to reveal the vibrational modes of the named chemical, the Infrared and Raman spectra were registered. Then, 13C and 113Cd solid-state NMR was employed to characterize this hybrid material using a polar solvent to conduct an investigation of the optical characteristics for the UV–visible range. Consequently, utilizing the highest occupied molecular orbital and the lowest unoccupied molecular orbital (HOMO–LUMO) calculations, the molecule’s energy gap (Eg) was determined. More so, the PL tests revealed two peaks at about 400 and 423 nm while the Hirshfeld surface (HS) analysis and DFT calculations were also carried out to acquire insight into the role of weak molecular interactions in the complex that affect the self-assembly process and crystal packing. In addition, molecular docking experiments with the 6U3Y, 1SAX, and 2D45 receptors reveal ideal postures with intriguing binding affinities of −5.2, −5.6, and −5.7 kcal.mol−1, respectively. Lastly, thermo-differential analysis techniques (DTA) and thermogravimetric analysis techniques (TGA) were used to account for the thermal degradation of the current complex.

Six nickel-lanthanoid heterometallic complexes based on 2,5-dichlorobenzoate and phen: Syntheses, structures and magnetic properties

Six new zero-dimensional (0D) Ni(II)-Ln(III) heterometallic complexes, [Ln2Ni2(2,5-DCB)10(phen)2] [Ln = Nd (1), Sm (2), Eu (3), Gd (4), Tb (5) and Dy (6), 2,5-HDCB = 2,5‑dichlorobenzoic acid, phen = 1,10-phenanthroline], have been successfully synthesized by the reactions of Ln(NO3)3·6H2O, Ni(NO3)2·6H2O, 2,5‑dichlorobenzoic acid, NaOH and 1,10-phenanthroline under solvothermal conditions. All of these complexes have been characterized by single-crystal X-ray diffraction, elemental analysis, FT-IR spectroscopy, powder X-ray diffraction (PXRD) and thermogravimetric analysis (TGA) and differential thermoanalysis (DTA). Complexes 1–6 are isomorphous and have a linear tetranuclear cluster structure formed by the 2,5-DCB anions linking the Ni(II) and Ln(III) ions. The adjacent tetranuclear molecules are further extended into a two-dimensional (2D) supramolecular architecture by the π–π interactions. The magnetic properties of 1, 2 and 4–6 were investigated in detail. Complex 6 displays a field-induced single-molecule magnet (SMM) behavior with a Ueff value of 10 K.

Growth, single crystal investigations, Hirshfeld surface analysis, DFT studies, molecular dynamics simulations, molecular docking, physico-chemical characterization and biological activity of novel thiocyanic complex with zinc transition metal precursor

The present work undertakes the study of novel thiocyanic complex, which have been obtained due to the interaction of cationic entities with the thiocyanate ligands. In fact, these latter are added to a transition metal leading to the production of novel solid-state complex that was studied and characterized by single crystal X-ray crystallography. However, (C11H18N2O)[Zn(SCN)4] crystallizes in orthorhombic system with the non-centrosymmetric space group P 212121, with the following lattice parameters: a = 8.4726(2) Å, b = 14.6043 (7) Å, c = 17.1927 (14) Å with V = 2127.3 (14) Å3 and Z = 4. Infrared spectrum was registered to revel the vibrational modes of the compound, add to the study of the optical properties using a polar solvent to carry out the UV–visible analysis. Thermogravimetric analysis techniques (TGA) and thermo-differential analysis techniques (DTA) were carried out to account for the thermal decomposition of complex. Furthermore, the antibacterial properties were determined against some bacteria. In order to gain insights into the role of weak molecular interactions in the complex that influence the self-assembly process and crystal packing, Hirshfeld surface analysis and DFT calculation were also performed. Furthermore, molecular docking and molecular dynamic simulations were performed for the compound against different antibacterial targets to identify to which target the compound show the best binding affinity. The MurF enzyme, which catalyzed the last cytoplasmic step of bacterial peptidoglycan synthesis, among the target was revealed to show better interactions with the enzyme and formed strong and stable intermolecular complex.

Growth and characterization of L-tyrosine magnesium chloride single crystal: A promising NLO crystal

New single Crystal of L-Tyrosine Magnesium Chloride (LTMC) was grown from aqueous solution by slow evaporation solution technique (SEST). The grown crystal was subjected to single crystal X-ray diffraction study which confirms that the grown crystal is orthorhombic system with the space group Pmn21. The grown crystals were characterized by Fourier Transform Infrared (FTIR) spectroscopic analysis to find the different modes of vibration due to various functional groups present in LTMC. The transmission spectrum of LTMC was recorded by UV–Vis spectrometer in the range between 200 nm and 800 nm which addressed the grown crystal has good optical transparency in the entire visible region and its energy band gap was determined. The thermal stability of the crystal was determined from thermo gravimetric and differential thermo analysis (TG-DTA) curve. The dielectric constant and dielectric loss has been studied as a function of frequency for various temperatures and the results were discussed in details. The frequency dependence of AC/DC conductivity studies for different temperature was carried out. The photoconductive behavior of the material is also investigated and the grown crystal has positive photoconductive nature. Mechanical strength of the grown crystal was estimated by using Vicker’s hardness test. The presence of second harmonic generation (SHG) for the grown crystal was confirmed by Kurtz Perry powder technique. All these studies indicate that the LTMC crystal can be considered as a potential candidate for the fabrication of optoelectronic devices.

Crystallization Process and Site-Selective Excitation of Nd3+ in LaF3/NaLaF4 Sol–Gel-Synthesized Transparent Glass-Ceramics

In this study, transparent oxyfluoride glass-ceramics (GCs) with NaLaF4 nanocrystals (NCs) were prepared by the sol–gel method for the first time. Three different molar ratios of La(CH3COO)3/Na(CH3COO) were used to obtain the GCs, which were sintered at 450, 550 and 650 °C for 1 min. X-ray diffraction (XRD) was employed to follow the evolution of the xerogel during the heat treatments and to study crystal growth for the three temperatures. In all cases, the LaF3 crystalline phase was present, but crystallization of NaLaF4 was only promoted at 650 °C. Thermogravimetric and thermodifferential analysis (TGA-DTA) and Fourier transform infrared spectroscopy (FTIR) were used to analyze the crystallization process. High-resolution transmission electron microscopy (HRTEM) was employed to confirm NaLaF4 crystallization and determine the size distribution. The incorporation of Nd3+ ion into NaLaF4 and LaF3 nanocrystals was confirmed by site-selective emission and excitation spectra. The Nd3+ emission intensities in both phases depend not only on the NaLaF4/LaF3 ratio but also on their emission efficiencies.

Mitigation of CO2 emissions by hydrotalcites of Mg3Al-CO3 at 0 °C and high pressure

This work shows the maximum CO2 capture capacity, using CO2 isotherms at 0, 20 and 30 °C and pressures of up to 35 atm, of four adsorbents with different particle size distribution and different pore size distribution: two hydrotalcites of Mg3Al-CO3, one synthesized in laboratory (C1) and another commercial (C2) and two calcined (C1 500 and C2 500) obtained from C1 and C2 by calcination at 500 °C for 2 h, respectively. The maximum capture capacities were obtained for samples calcined (CLDH), 98.16 mg·g−1 for C2 500 sample and 142.02 mg·g−1 for sample C1 500, both at 0 °C and 34.28 atm. The capture capacity of the C2 500 sample was the least influenced by temperature changes, which could be related to the porous structure of the samples. Consequently, for applications that are carried out between 0 and 30 °C, the best sample will be C2 500. Previously the samples were characterized by X-ray diffraction, transmission and scanning electron microscopy, thermogravimetric and thermo-differential analysis, particle size distribution and pore size distribution by N2 adsorption isotherms. The CO2 adsorption isotherms data were adjusted to the Freundlich, Langmuir, Dubinin-Radushkevich y Temkin models. These two last models confirmed that the nature for CO2 adsorption was physical. In short, this work showed the usefulness of calcined hydrotalcite as a CO2 adsorbent, using low temperature (0 °C) and high pressure (34.28 atm) as working conditions.