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In this paper, we propose an approach based on parameter β, which equals the free volume in a unit cell normalized to the van der Waals volume of the molecules. The analysis was carried out within a cluster including two-component crystals [CF1 + CF2], in which one of the components remains constant (CF1) and the other varies (CF2). Linear correlation equations, such as β(CC) = C + D·β(CF2), linking the β(CC) parameter of the two-component crystals with the similar parameter β(CF2) of the single-component crystal for the strictly fixed temperatures were derived on the basis of the crystallographic experimental data. The coefficients of the correlation equations for different clusters were analyzed. A relationship was discovered between the correlation coefficient D and the HYBOT descriptor describing the donor and acceptor interactions with the other molecules. A graphic method was developed for analyzing the β(CC) parameter for the cocrystals belonging to the same cluster relative to the β parameter values of the individual compounds β(CF1) and β(CF2). The correlation equations derived in the study give an opportunity to evaluate the unit cell volume of a hypothetical cocrystal knowing only the crystal structure of a single-component crystal of one of the cocrystal components. [ABSTRACT FROM AUTHOR]

The paper reports on the synthesis, crystal structure, thermal and magnetic properties of spin crossover (SCO) salts containing the [Fe(bpp)2]2+ cation (bpp = 2,6-bis(pyrazol-3-yl)pyridine) and different rigid polycarboxylate anions, such as anthracene-9,10-dicarboxylate (ADC), benzene-1,3,5-tricarboxylate (BTC) and biphenyl-4,4′-dicarboxylate (BPDC). Compound [Fe(bpp)2](ADC)·9H2O (1) shows a porous hydrogen-bonded structure with water molecules sitting in the channels. It contains low-spin (LS) Fe2+ cations that undergo crossover to the high-spin (HS) state upon dehydration. Anhydrous 1 remains HS on cooling at low temperatures. A similar magnetic behaviour is obtained for the partially protonated BTC salt [Fe(bpp)2](HBTC)·5H2O (2), showing a spin change concomitant with dehydration to a HS phase that undergoes gradual and partial SCO on cooling, affecting 25% of the Fe2+ cations. Instead, the BPDC salt [Fe(bpp)2](BPDC)·5H2O (3) has a ground HS state in its fully hydrated form. [ABSTRACT FROM AUTHOR]

Radical-cation salts of formula β?-(BEDT-TTF)4[(H3O)Fe(C2O4)3]·guest have produced a large number of superconductors and provided a route to introduce magnetism and chirality into the same multifunctional material. A relationship has been found in these salts between the length of the b axis and the superconducting Tc. Increasing the b axis length by introducing larger guest molecules, such as benzonitrile and nitrobenzene, gives the highest superconducting Tcs in this family of salts. Smaller guests such as pyridine show no superconducting transition, whilst asymmetrical guests which are larger than nitrobenzene have given a different bilayered structure. Other potential guest molecules have been limited by their ability to be used as the solvent in which the crystals are grown via electrocrystallisation. This paper reports a method which introduces guest molecules into the crystal which are a solid or liquid additive within the crystal-growing solvent 1,2,4-trichlorobenzene:ethanol. We present the crystal structures of five new BEDT-TTF radical-cation salts with tris(oxalato)ferrate anions using guest molecules toluene, phenol, benzaldehyde, 4-bromobenzaldehyde, and kojic acid. [ABSTRACT FROM AUTHOR]

We previously reported that Zr substitution improves the chemical stability of Ba3Y4O9 and nominally 20 mol% Zr-substituted Ba3Y4O9 is an oxide-ion conductor at intermediate temperatures (500–700 °C). However, the influence of Zr substitution on the structural properties of Ba3Y4O9 was poorly understood. This paper aims to comprehensively understand the crystal structure of Ba3Y4O9 with Zr substitution by powder X-ray diffraction (XRD), extended X-ray absorption fine structure (EXAFS) measurements, and first-principles calculations. From the results, firstly we found that the hexagonal unit cell of Ba3Y4O9 reported in the database should be revised as doubled along the c-axis in terms of the periodicity of oxide-ion positions. The revised unit cell of Ba3Y4O9 consists of 18 layers of BaO3 and 24 layers of Y which periodically stack along the c-axis. In this work, we focused on the cationic lattice and noticed that the periodical stacking of Ba and Y layers comprises a similar sequence to that in the body-centered cubic (BCC) structure. There are two regions in the Ba3Y4O9 structure: one is a hetero-stacking region of Ba and Y layers (Ba–Y–Ba–Y–Ba) and the other is a homo-stacking region (Ba–Y–Y–Ba). It is noteworthy that the former region is similar to a cubic perovskite. In Zr-substituted Ba3Y4O9, Zr ions preferentially substitute for Y ions in the hetero-stacking region, and therefore the local environment of Zr ions in Ba3Y4O9 is quite similar to that in BaZrO3. Besides, the Zr substitution for Y in Ba3Y4O9 increases the fraction of the cubic-perovskite-like region in the stacking sequences. The structural change in the long-range order strongly affects the other material properties such as chemical stability and the ionic-conduction mechanism. Our adopted description of perovskite-related compounds based on the stacking sequence of the BCC structure should help in understanding the complex structure and developing new perovskite-related materials. [ABSTRACT FROM AUTHOR]

Viologen is capable of generating radicals in response to an applied stimulus, giving it an abundance of stimuli responsive properties. However, the radical state of viologen is often unstable, which hinders further studies on the radical properties of viologen. In this paper, the salicylhydrazide group was chosen as a donor group to bond with mono-substituted bipyridyl groups to obtain three novel D–A type viologen compounds. The compounds were harvested and characterized by X-ray single crystal diffraction, optical spectroscopy, EPR and DFT calculation, etc. The results show that compounds 1–3 adopt certain free radical states at room temperature under ambient light, which may be attributed to the electron-donating properties of the salicylhydrazide group and the degree of system conjugation. In addition, compound 1 has a hydrochromic property and compounds 2 and 3 have photocurrent effects under UV radiation. [ABSTRACT FROM AUTHOR]

The oxidation state (OS) holds significant importance in the field of chemistry and serves as a crucial parameter for tracking electrons. Lanthanide (Ln) elements predominately exhibit a + III oxidation state, with a few elements such as Ce, Pr, Nd, Tb, and Dy able to achieve a + IV oxidation state. Over the past century, numerous attempts to synthesize Pr(V) have been made without success until recent reports on Pr(V) oxides and nitride-oxide in the gas phase expanded our understanding of Ln elements. However, the formation of Pr(V) in the condensed phase remains an open question. In this work, based on advanced quantum chemical investigations, we predict that formation of the solid-state CsPrVF6 from Pr(III) and Pr(IV) complexes is exothermic, indicating that CsPrVF6 is stable. The crystal structure comprises [PrF6]− octahedral clusters occupying the interstitial spaces of Cs cations. Electronic structure analysis reveals that the CsPrF6 crystal has a closed-shell structure and that Pr reaches its highest oxidation state of + V. The results indicate that the existence of Pr(V) in solid-state Ln fluorides is not impossible, which enriches our understanding of high-valence Ln compounds. [ABSTRACT FROM AUTHOR]

Metal chalcogenides, as a new class of semiconductor materials, have a broad range of applications in synthetic chemistry due to their rich structures and excellent properties. We have synthesized two selenoantimonates A4Zn2Sb2Se7 [A = Rb(1), Cs(2)] under solvothermal conditions in the visible region using a band gap optimization strategy with alkali metals as structure-directing agents. Compounds 1 and 2 have a two-dimensional layered structure consisting of charge-balanced Rb+(1) or Cs+ (2) cations and [Zn2Sb2Se7]4- anions with novel 20-membered rings (20-MR) [Zn6Sb4Se10] with an aperture of 5.6949 × 13.7741 Ų formed in the middle. Furthermore, we have investigated the crystal structure, band gap, photoelectronic properties, and energy band structure. [ABSTRACT FROM AUTHOR]

Treating conic tetra-para-ethylacetato-calix[4]arene (1) with 2.2 equivalents of K2CO3 and 4 equivalents of 6-bromomethyl-6′-methyl-2,2′-bipyridine affords the expected fully substituted podand, mainly in its 1,3-alternate conformation (2). This tube-like bipyridyl derivative 2 was subjected to complexation studies with CoCl2·6H2O to give a blue tetra cobalt(II) complex species (3). This complex displays a unique group of 6 aromatic bipyridyl 1H-NMR resonance signals demonstrating its high symmetry, while X-ray diffraction studies showed the presence of 3 expected tetrahedral bpy(CoCl2) units and 1 original trigonal bipyramidal unit involving the adjunction of a fifth ligand assumed to be H2O that could participate in the crystal scaffold. [ABSTRACT FROM AUTHOR]

We describe a new quadrupolar NMR crystallography guided crystal structure prediction (QNMRX-CSP) protocol for the prediction and refinement of crystal structures, including its design, benchmarking, and application to seven organic HCl salts. Five HCl salts with a limited number of low-energy conformations were chosen as model systems for benchmarking: betaine HCl, glycine HCl, D -alanine HCl, guanidine HCl, and aminoguanidine HCl; two were chosen for blind tests: N,N′-dimethylglycine HCl and metformin HCl. The QNMRX-CSP protocol uses experimental 35Cl solid-state NMR (SSNMR) spectra and X-ray diffraction (XRD) data in tandem with Monte Carlo simulated annealing and dispersion-corrected plane-wave density functional theory (DFT-D2*) calculations. The protocol comprises three modules: (i) the assignment of motion groups, (ii) a Monte Carlo simulated annealing algorithm for generating tens of thousands of candidate structures, and (iii) DFT-D2* geometry optimizations of structural models and concomitant computation of 35Cl EFG tensors. Key benchmarked metrics are used for retaining the best candidate structures, including unit cell parameters, static lattice energies, and EFG distances (ΓEFG). The protocol is shown to generate structural models that are excellent matches with experimental crystal structures that have been DFT-D2* geometry optimized, as validated by crystallographic R-factors (R) and root-mean squared distances (RMSDs) of atomic positions that are well below 10% and 0.2 Å, respectively. Finally, consideration is given to the use of the QNMRX-CSP protocol as a standalone technique or in concert with other NMRX methods and Rietveld refinements, and possible applications employing other quadrupolar nuclei (i.e., 14N and 17O). [ABSTRACT FROM AUTHOR]

A high-temperature synthetic approach is used to prepare a series of pseudo-binary phases- Co2-xNixZn11. In the structures of Co2-xNixZn11, the statistical distribution between Co and Ni that is suggested by compositional analysis is confirmed by combined refinements of X-ray and neutron powder diffraction (NPD) experimental data. The aforementioned phases adopt a body-centered cubic lattice with a noncentrosymmetric space group I43m (217). Their crystal structures comprise two 26-atom γ-brass clusters. Each γ-cluster is made of four sequential polyhedral shells: inner tetrahedron (IT), outer tetrahedron (OT), octahedron (OH), and distorted cuboctahedron (CO). Diffraction experiments and the computations endorse that the OT site is statistically distributed by Co and Ni atoms, while the other three sites (IT, OH, and CO) are occupied by Zn atoms. The density of states (DOS) curve for Co1.5Ni0.5Zn11 displays a similar feature as binary Co2Zn11, whereas the wide pseudo-gap is formed near EF as Ni-concentration increases in Co2-xNixZn11. Bonding analysis shows that this specific atomic distribution nearly optimizes heteroatomic Co/Ni--Zn contacts in the Co1.0Ni1.0Zn11 and Co0.5Ni1.5Zn11. The Co1.7Ni0.3Zn11 exhibit paramagnetic behavior, whereas Co0.5Ni1.5Zn11 shows distinct diamagnetic behavior. With the increase in Ni concentration in the structure of Co2-xNixZn11, Ni atoms gradually substitute the Co atoms at OT sites; hence, magnetic characteristics change from para- to diamagnetism. [ABSTRACT FROM AUTHOR]

The equimolar reaction between 1,9-bis(N,N-dimethylaminomethyl)-5,5′-diphenyldipyrromethane, H2L1 or 1,9-bis(3,5-dimethylpyrazolylmethyl)-5,5′-diethyldipyrromethane, H2L2 and [NiCl2(DME)] in the presence of KH yielded the neutral mononuclear nickel(II) complexes [Ni(L1)-κ4N,N,N,N], 1 and [Ni(L2)-κ4N,N,N,N], 2, respectively. Their X-ray structures revealed the formation of triple chelation by the ligand in both structures with quite different nickel(II)-surrounded square planar geometries owing to the steric difference between –NMe2 and 3,5-dimethylpyrazolyl groups. While the –NMe2 group substituted ligand L1 afforded nickel complex 1 with a plane of symmetry, 3,5-dimethylpyrazole substituted L2 rendered helical chirality in the structure of complex 2. Both the enantiomers (Δ and Λ) of complex 2 were observed in the crystal lattice. Their solution state behaviors were consistent with the solid-state structures as monitored by 1H NMR spectroscopy. Both the enantiomers of complex 2 were present in a dynamic equilibrium in solution and studied by variable temperature 1H NMR spectroscopy. Similar to the chiral complex, the corresponding ligand H2L2 also exhibited chirality as shown by its crystal structure and the two ligand enantiomers participated in a very fast dynamic interconversion, which became slower upon metalation. [ABSTRACT FROM AUTHOR]

Based on crystal engineering, three Zn/Cd-based metal--organic frameworks (MOFs) (FUM-153(Zn--H), FUM-167(Cd--H), and FUM-176(Cd--NH2)) were successfully prepared from rigid O-donor/flexible N-donor linkers (H2bdc (terephthalic acid) (L(O) H) or NH2-H2bdc (2-aminoterephthalic acid) (L(O) NH2) and bpfb (N,N'- 1,4-(phenylene) diisonicotinamide) (L(N))) with Zn/Cd ions. Structurally, the major difference among the FUMs is the various behaviors of the DMF solvent in the lattice or the coordination environment of the structures. This study investigated the effect of hydrogen bonding of NH2 substitution in 2-D layer linkers and its effect on the layer architecture. The results showed that hydrogen bonding indirectly affects the coordination of DMF solvent to the metal center and the porosity. To investigate the effect of the NH2 substitution in the presence or absence of the DMF solvent in the FUMs, the Cambridge Structural Database (CSD) was surveyed for similar structures with the L(O) H and L(O) NH2 linkers. Remarkably, the obtained data suggested that the existence of NH2 substitution may reduce the probability of the coordination of DMF to the metal centers. Theoretical studies were carried out to explore the gas adsorption performance of the title FUMs. A better CH4 adsorption compared to CO2 for all FUMs was observed. It is worth noting that CH4 and CO2 gas adsorption in FUM-176(Cd--NH2 substitution in 2-D layer linkers prevented the entering of DMF molecules into the framework (lattice or coordinated solvent). Consequently, more accessible pores are provided for gas molecules. The work demonstrates the role of linker functionality in the crystal structure, pore size, and gas adsorption properties. [ABSTRACT FROM AUTHOR]2 substitution in 2-D layer linkers prevented the entering of DMF molecules into the framework (lattice or coordinated solvent). Consequently, more accessible pores are provided for gas molecules. The work demonstrates the role of linker functionality in the crystal structure, pore size, and gas adsorption properties. [ABSTRACT FROM AUTHOR]

In the presented work, the structure dependence as well as luminescence features of a wide range of hybrid crystals based on lead halides and a homologous series of alkyl diamines from 1,4-diaminobutane to 1,8-diaminooctane are investigated. The structure of several previously undescribed hybrid crystals has been established. The even–odd effect of alkanes and its influence on the structure of such hybrid crystals have been demonstrated for the first time. The luminescence properties of the crystals and their dependence on the type of anion as well as the length and oddity of the organic cation are described in detail. The obtained data expand our knowledge of the relationship between the structure of the organic cation, including its parity and structure, and the electronic and optical properties of the hybrid crystals. [ABSTRACT FROM AUTHOR]

A new N-(4-fluorobenzyl) N-(pyridin-2-ylmethyl) dithiocarbamate ligand (fbpm) having structural similarity to clinically approved antihistaminic drugs (viz. pheniramine, chlorpheniramine, and brompheniramine) and its four metal complexes [Co(fbpm)3] (1), [Ni(fbpm)2] (2), [Cu(fbpm)2] (3), and [Zn(fbpm)2] (4) were successfully synthesized and characterized by various techniques i.e. elemental analysis, FT-IR spectroscopy, HR-MS, NMR spectroscopy, and absorption and emission spectroscopy. Furthermore, complexes 1 and 2 were characterized by single crystal X-ray diffraction. Complex 1 adopts distorted octahedral geometry around the Co(III) center while complex 2 adopts distorted square planar geometry around the Zn(II) center. X-ray data also showed various weak intermolecular C–H⋯F and C–H⋯N hydrogen bonding interactions leading to supramolecular architectures in complexes 1 and 2. The thermal decomposition study of complexes 1–4 analyzed by TGA shows that they are thermally stable up to 150 °C and also gives strong evidence for the formation of respective metal sulfides at higher temperatures. The antihistaminic activity of the ligand (fbpm) and its complexes 1–4 was examined against clonidine and haloperidol-induced catalepsy in Swiss albino mice of either gender in an in vivo animal model. The result shows that these synthesized compounds have antihistaminic potential to inhibit clonidine-induced catalepsy and may be targeted for different allergic conditions. Complex 3 showed maximum reduction in clonidine-induced catalepsy after 180 minutes of treatment when compared with the induced control. [ABSTRACT FROM AUTHOR]

The synthesis of amides holds great promise owing to their impeccable contributions as building blocks for highly valued functional derivatives. Herein, we disclose the design, synthesis and crystal structure of a mixed-ligand ruthenium(II) complex, [Ru(η6-Cym)(O,O-PLY)Cl], (1) where Cym = 1-isopropyl-4-methyl-benzene and O,O-PLY = deprotonated form of 9-hydroxy phenalenone (HO,O-PLY). The complex catalyzes the aerobic oxidation of various primary amines (RCH2NH2) to value-added amides (RCONH2) with excellent selectivity and efficiency under relatively mild conditions with common organic functional group tolerance. Structural, electrochemical, spectroscopic, and computational studies substantiate that the synergism between the redox-active ruthenium and π-Lewis acidic PLY moieties facilitate the catalytic oxidation of amines to amides. Additionally, the isolation and characterization of key intermediates during catalysis confirm two successive dehydrogenation steps leading to nitrile, which subsequently transform to the desired amide through hydration. The present synthetic approach is also extended to substitution-dependent tuning at PLY to tune the electronic nature of 1 and to assess substituent-mediated catalytic performance. The effect of substitution at the PLY moiety (5th position) leads to structural isomers, which were further evaluated for the catalytic transformations of amine to amides under similar reaction conditions. [ABSTRACT FROM AUTHOR]

Symmetry-forming closest approaches of aromatic rings; 'Symthons', are usually the strongest interactions in halobenzene crystal structures. Where they combine to create π–π stacking, they are as strong as hydrogen bonds. This π–π stacking is disrupted when fluorine is present, as revealed in this analysis of all 290 closest aromatic approaches in the crystal structures of halobenzenes. Closest aromatic approaches involving fluorine show fewer examples of 'Symthon I' π–π stacking, and more examples of offset translations with larger displacements. Edge⋯face approaches are also more common in the presence of fluorine, frequently accommodating fluorine atoms in the 'edges'. Some edge⋯face approaches do not embody any symmetry. These findings are consistent with lower melting points and favourable connections between fluorine and positively charged carbon atoms. [ABSTRACT FROM AUTHOR]

This article demonstrates the ability of electron diffraction (3D ED, or simply ED) for solving complex structures of active pharmaceutical ingredients (API) and its relevance in the drug development process. The study focuses on febuxostat (FEB), a selective inhibitor used for treating gout. FEB exhibits multiple solid forms, with the crystal structure of the marketed polymorph (form A) being unknown despite its commercial availability. In this work, the crystal structure of form A was successfully determined using both ED and single-crystal X-ray diffraction techniques (SC-XRD). Notably, the crystal growth attempts delivered very small crystals, suitable for ED only, while larger single-crystals for SC-XRD were unintentionally obtained in an experiment aiming for the co-crystallization of FEB with benzoic acid. The results show that ED is a valuable and reliable tool for crystal structure determinations, with comparable accuracy to X-ray crystallography. This study highlights the possibility of incorporating ED in the pharmaceutical research and development process, offering a reliable and efficient approach for crystal structure analysis. It emphasizes the significance of combining crystal structure knowledge with theoretical methods in understanding complex polymorphic systems. Furthermore, it addresses the ED potential in overcoming the challenges in characterizing solid forms across the drug development process. [ABSTRACT FROM AUTHOR]

A comprehensive series of mononuclear Ln(III) complexes based on N3-tridentate Schiff-base ligand L have been synthesized using triflate or nitrate lanthanide(III) metal salts. X-ray structural characterization shows that the obtained complexes exhibit a variety of coordination modes around the Ln(III) centers tuned through appropriate counterions and reaction conditions. Examination of the above-mentioned factors reveals that, in the case of all lanthanide assemblies, we observe anion-driven structural diversity. Tuning of the crystal structure of the formed supramolecular systems is also highly influenced by the lanthanide contraction phenomenon, directly resulting in a series of isostructural groups, with general formulae of [ML2(OTf)nX3−n](OTf)3−n, if n = 2, X = MeCN (except for Yb), and if n = 1, X = MeOH in the triflate series, and [ML(NO3)3(X)](Y), where X and Y represent MeOH, MeCN or H2O, respectively, in the nitrate series. The present study gives insight into the lanthanide contraction phenomenon within the tridentate N-heterocyclic coordination architectures of Ln(III) systems and can serve for targeted manipulation of properties through molecular tectonics and crystal engineering aspects in the domains, where subtle changes of the Ln(III) coordination spheres are important like molecular magnetism or catalysis. [ABSTRACT FROM AUTHOR]

Because global sulfur emission has escalated, the development of high-efficiency deep desulfurization techniques has become imperative. Herein, to design a high-activity heterogeneous catalyst for the aerobic oxidation desulfurization (AODS) of fuel, Dawson-type polyoxometalate (H6P2W18O62 abbreviated as D-P2W18), characterized by its high activity and strong oxidative capacity, was applied to react with CuCl2·2H2O and H3TZI via a one-pot hydrothermal method. Consequently, blue crystalline H6P2W18O62@[Cu6O(TZI)3(H2O)6]4 (abbreviated as D-P2W18@rht-MOF-1; rht-MOF-1 = [Cu6O(TZI)3(H2O)6]4·nH2O) was afforded. X-ray diffraction analysis indicated that D-P2W18 was successfully encapsulated in two different cages of rht-MOF-1, which is distinct from the crystal structure of Keggin-type POMs@rht-MOF-1. It represents the first crystal structure of Dawson-type POMs@rht-MOF-1. When D-P2W18@rht-MOF-1 was employed as a catalyst for AODS under ambient oxygen pressure with the assistance of surfactant dioctadecyl dimethyl ammonium chloride (DODMAC), it demonstrated remarkable catalytic capability and recyclability for both model fuel and commercial diesel. Further, the AODS reaction mechanism, identified as a free radical oxidation–reduction process, was verified by way of radical quenching experiments, EPR and XPS analysis. This approach offers a feasible route for the synthesis of new Dawson-type POMs@MOFs of heterogeneous catalysts for highly active AODS of fuel. [ABSTRACT FROM AUTHOR]

To clarify the hydrogen storage mechanism of Mg(In) solid solution, the hydrogenation and dehydrogenation characteristics of Mg0.9In0.1 alloy are systematically studied in this work. It is found that the Mg0.9In0.1 solid solution is first hydrogenated to Mg3In and MgH2 under a hydrogen atmosphere. The polymorphism of Mg3In leads to different hydrogenation features of the solid solution in various temperature ranges. Consequently, the reversible dehydrogenation reactions have somewhat distinct enthalpy changes due to the different crystal structures of Mg3In. When the hydrogenation temperature is not lower than 340 °C, Mg3In can be further hydrogenated to (Mg1−xInx)3In and MgH2. The hydrogenation reactions of both β′-Mg3In and β-Mg3In are also reversible although they have sloping hydrogenation and dehydrogenation plateaus in pressure–composition isotherms. This work provides new insights into the hydrogen storage mechanism of Mg(In) solid solution. [ABSTRACT FROM AUTHOR]

In mitochondria, the detoxification of molar excess H2S as polysulfide proceeded via an oxidation process promoted by Cu/Zn containing superoxide dismutase (SOD1) enzyme, which has been very recently reported as the alternative enzyme for cytosolic H2S oxidation. Herein, we present Ni(II) complexes bearing the terminal SH group as a synthetic functional analogue for the sulfide oxidase function of SOD1. Synthesis, crystal structure and complete spectroscopic characterization of two sets of complexes, [NiLOMe/tBu(PPh3)] (2OMe/tBu) and tetraethyl salt of [NiLOMe/tBu(SH)]−1 (3OMe/tBu), were described (LOMe = (E)-2-methoxy-6-(((2-sulfidophenyl)imino)methyl)phenolate and LtBu = (E)-2,4-di-tert-butyl-6-(((2-sulfidophenyl)imino)methyl)phenolate). Under anaerobic conditions, 3OMe/tBu responded to a catalytic sulfur atom transfer (SAT) reaction with PPh3 to produce SPPh3. The SAT reaction was analyzed using detailed studies of 1H and 31P NMR spectra. Finally, the SAT reactivity pattern was compared with the same in the native enzyme of SOD1. [ABSTRACT FROM AUTHOR]

Cyanurate or isocyanurate compounds containing plane π-conjugated groups usually have giant optical anisotropy, which are promising candidates for optoelectronic functional materials. In this work, a new alkali-metal isocyanurate was successfully synthesized by a hydrothermal method, namely Cs3(H2C3N3O3)3(H3C3N3O3)·3H2O, belonging to the triclinic crystal and P1¯ space group. The compound has two-dimensional layers constructed with (H2C3N3O3)− and (H3C3N3O3) six-membered rings extending along the ab plane. The characterization results show that it exhibits a wide band gap (5.03 eV) and a large birefringence (0.23 at 1064 nm). In addition, in order to evaluate the relationship between the crystal structure and its optical properties, the first-principles calculation was also carried out. This work provided a possible candidate for anisotropic optical crystals applied in the ultraviolet region. [ABSTRACT FROM AUTHOR]

In this work, PbSb2O6-type oxides LaMTeO6 (M = Ga3+ and Mn3+) were synthesized and structurally characterized by Rietveld refinements against high-resolution X-ray powder diffraction data. The Ga3+/Te6+ partial ordering within the honeycomb-like two-dimensional [GaTeO6]3− anionic layer leads to the loss of the inversion center between Ga3+ and Te6+; however the inversion center on the 3¯-roto-inversion axis is preserved, thereby resulting in a 2-fold PbSb2O6-type superstructure by doubling the c-axis associated with a structural symmetry descending from the original P3¯1m to P3¯1c symmetry. In contrast, LaMnTeO6 (P21/c) adopts a monoclinically distorted 4-fold superstructure with lattice dimensions of a ≈ aH, b ≈ √3aH, c ≈ 2cH, where aH and cH represent the lattice parameters of trigonal PbSb2O6. The formation of this P21/c-superstructure is attributed to the combination of complete Mn3+/Te6+ ordering and the first-order Jahn–Teller distortion of Mn3+ with the electronic configuration of d4. Such a monoclinic distortion can effectively lift the Mn3+ spin moments arranged on the triangular sublattice, resulting in a sharp peak for antiferromagnetic transition, which is in stark contrast to subtle magnetic transitions for PbSb2O6-type tellurates AMn(VI)TeO6 (A = alkaline earth and Pb2+) and LnCrTeO6 (Ln = rare earth) with higher structural symmetry. Our findings highlight that the electronic configuration effects of M-cations play a critical role in controlling the structure symmetry of LaMTeO6, providing a strategy to fine-tune the crystal structures and physical properties. [ABSTRACT FROM AUTHOR]

New fluorinated dibenzo-1,2,5,6-tetrathiocines 1 and 2 were synthesized by a novel condensation of 1,2-disulfenyl chlorides under the influence of elemental Cu, and structurally defined in the solid state, solution, and gas phase by single-crystal XRD, variable-temperature 19F NMR and NOESY, and DFT calculations. Crystalline 1 and 2 exhibited the C2h chair and C2 twist molecular conformations, respectively. Unlike 1 displayed only C⋯S shortened intermolecular contacts, crystal structure of 2 featured F⋯π, F⋯F, F⋯S and S⋯S contacts. In toluene solutions at 296 K, both twist and chair conformers were observed in the ∼1 : 1 and ∼7 : 1 ratios for 1 and 2, respectively. For 1, the twist ↔ chair conformer interconversion was practically temperature-independent, and for 2 revealed ΔH ∼3.5 kJ mol−1 and ΔS ∼4.4 J K−1 mol−1. With DFT, the PESs for twist–chair transformation and twist–twist racemization were analyzed and the TSs exhibiting twist–halfchair and boat conformations, respectively, were found. Several additional stationary points on the PESs, corresponding to hidden intermediates and bifurcation points and featuring twistboat and halfchair conformations were detected. In chloroform solution under sunlight, 1 underwent 1,2,5,6-tetrathiocine → 1,2,3,6-tetrathiocine isomerization whose product was characterized by XRD. [ABSTRACT FROM AUTHOR]

Two new pyrazolidine-3,5-dione derivatives namely (Z)-4-(2-(4-bromophenyl)hydrazono)-1-phenylpyrazolidine-3,5-dione (2) and (E)-1-phenyl-4-((pyridin-2-ylamino)methylene)pyrazolidine-3,5-dione (3) were synthesized and their structures were elucidated by single-crystal X-ray analysis along with spectroscopic techniques. Density functional theory (DFT) studies were carried out to examine the distribution of charge, and natural bond orbital (NBO) analysis and frontier molecular orbital (FMO) analysis were carried out. Hirshfeld surface analysis was carried out to examine the intermolecular interactions, revealing a prevalence of H⋯H interactions in the crystals of both molecules. NBO analysis was carried out to investigate the stabilization energy, while MEP analysis was conducted to explore regions susceptible to nucleophilic and electrophilic attacks. The molecules were screened for their medicinal potential based on physiochemical and pharmacokinetics including (gastrointestinal) GI absorption, blood brain barrier (BBB) permeation, skin permeation capability, Caco-2 permeability, Madin–Darby canine kidney (MDCK) permeability, drug metabolism by the cytochrome P450 (CYP) family of liver enzymes, and toxicity evaluations. The expected metabolic reactions in the real cell system and the resulting metabolites along with their polarities for the determination of the probability of excretion from the body and drug-likeness were studied. To investigate the anticancer potency of 2 and 3, both were docked with three enzymes as drug targets for anticancer studies including HER2 (PDB ID: 3WSQ), EGFR (PDB ID: 5WB7), and the extracellular domain of the Tdp enzyme (PDB ID: 6N0D). From the calculated binding energies and inhibition constants, 2 is a better inhibitor of the target substrates than 3. [ABSTRACT FROM AUTHOR]

Hybrid halide perovskite-like materials have recently attracted great interest due to their potential applications in optoelectronic devices, energy storage and the semiconductor industry. In this work, two tin(IV) based organic–inorganic hybrid compounds [Cl–(CH2)2–NH3]2SnCl6(1) and [Cl–(CH2)2–NH3]2SnBr5.65Cl0.35(2) were prepared by the reaction of 2-chloroethylamine hydrochloride with SnX2 (X = Cl, Br) in the corresponding concentrated halogen acids. Single-crystal X-ray diffraction analysis reveals that compounds (1) and (2) are isotypic and crystallize in the monoclinic system with space group P21/m. The asymmetric unit of the crystal structure in each compound is composed of an independent [SnX6]2− anion charge balanced by [Cl–(CH2)2–NH3]+ cations, where X is a halogen. Differential scanning calorimetry (DSC) and electric measurements show that no phase transition occurs in the hybrid compounds over the temperature range of 298–453 K. Interestingly, both materials exhibit a semiconducting property with optical bandgaps of 4.7 eV for (1) and 2.94 eV for (2). Photoluminescence (PL) measurements evidenced the presence of green emissive traps activated by excitation below the optical gap for the [Cl–(CH2)2–NH3]2SnCl6(1) compound, resulting in an emissive color change of the crystals, from blue to green. These findings of Sn(IV)-based metal halides with prominent semiconducting behaviors and photoluminescence properties contribute to the exploration of new types of hybrid perovskite-like with adjustable properties. [ABSTRACT FROM AUTHOR]

In this study, three supramolecular compounds, namely [Na(18-crown-6)]ReO4 (1), [K(18-crown-6)]ReO4 (2) and [NH4(15-crown-5)2]ReO4 (3) were synthesized and characterized using microanalysis, thermogravimetric, differential scanning calorimetric and powder X-ray diffraction techniques, among others. Herein, 15-crown-5 and 18-crown-6 represent 1,4,7,10,13-pentaoxacyclopentadecane and 1,4,7,10,13,16-hexaoxacyclooctadecane, respectively. Both 1 and 2 experienced one-step reversible phase transition at ∼436 K and ∼360 K, respectively, while 3 underwent three steps of reversible phase transitions at ∼289 K, ∼352 K and ∼380 K. A dielectric anomaly occurred at ∼433 K (∼363 K) for 1 (2), consistent with the temperature obtained from DSC measurement. In the dielectric spectra of 3, anomalies were observed at ∼386 K and ∼433 K, corresponding to two thermal anomalies observed at higher temperatures in the DSC plot. However, there was an absence of dielectric response around 289 K where a thermal anomaly appeared in the DSC plot. The distinct crystal structures, phase transitions and dielectric properties in 1–3 stem from the degree of compatibility between the radii of M+ (Na+, K+ and NH4+) and the ring sizes of crown ethers (18-crown-6 and 15-crown-5). [ABSTRACT FROM AUTHOR]

3-Nitro-1,2,4-triazole-5-one (NTO) has received wide attention and has applications owing to its excellent detonation performance and low sensitivity. A new crystal form of NTO was prepared via the solvent evaporation method and named γ-NTO. Its crystal properties were studied through single-crystal X-ray diffraction, and the results indicated that the unit cell of γ-NTO belongs to the monoclinic space group Pc, with eight molecules in the single unit cell. The density of this crystal is calculated to be 1.907 g cm−3, which is higher than that of β-NTO and similar to that of α-NTO. The crystal morphology was calculated to be a polygonal shape with a symmetrical growth pattern using the reactive force field. Based on the analysis of reactive molecular dynamics, the thermal decomposition mechanism of different crystal forms of NTO was elucidated, and the results showed that γ-NTO demonstrates higher gas production, providing a successful way to enhance detonation performance. The results of IR and differential thermal analysis (DTA) support the above conclusions. [ABSTRACT FROM AUTHOR]

Cesium lead halide (CsPbX3) perovskite quantum dots (PQDs) have attracted attention for use as absorber materials in photovoltaics as they show tuneable bandgap energy and high photoluminescence quantum yields together with the potential to demonstrate long-term stability and simple solution processability. Currently, the colloidal synthesis of PQDs relies to a large extent on the use of toxic and fossil derived solvents as the reaction medium. Alternative methods that partially or completely replace such solvents are anticipated as a step forward in meeting the sustainability criteria for the large-scale synthesis of PQDs. Herein, we report an eco-friendly sonochemical-assisted synthesis of CsPbBr3 PQDs using commercial vegetable oil solvents as the reaction medium. The effect of different vegetable oils on the synthesis and properties of PQDs was investigated in detail. The as-prepared CsPbBr3 colloids show similar photoluminescence (PL) spectra and crystalline structure to colloids obtained in mineral oil, which was used here for comparative purposes. Furthermore, a smaller amount of the optically inactive Cs4PbBr6 hexagonal crystalline phase was detected in the green synthesis compared to mineral oil-based synthesis. Finally, spin-coated thin films were produced, demonstrating the processability of the colloidal PQDs obtained via the green synthesis described here. [ABSTRACT FROM AUTHOR]

In this study, high-quality ε-Ga2O3 epitaxial layers were grown on a silicon carbide (4H-SiC) substrate via metal–organic chemical vapor deposition (MOCVD) with a two-step growth method. A (004) rocking curve full width of half maximum (FWHM) of the ε-Ga2O3 epitaxial layer as small as 0.09° (341 arcsec) is achieved, which is currently the lowest reported value obtained using the MOCVD method. The effect of nucleation layer structure on the crystalline quality is investigated. As a result, a high-temperature nucleation layer, composed of a mixed phase (β + ε) structure with low grain density is beneficial for the growth of high-quality ε-Ga2O3 films. A growth model was proposed to explain the mechanism whereby high quality ε-Ga2O3 hetroepitaxy is achieved. This study provides valuable insight for the development of epitaxial ε-Ga2O3 on 4H-SiC substrates. [ABSTRACT FROM AUTHOR]

An NMR-guided procedure for refining crystal structures has recently been introduced and shown to produce unusually high resolution structures. Herein, this procedure, is modified to include 15N shift tensors instead of the 13C values employed previously. This refinement involves six benchmark structures and 45 15N tensors. All refined structures show a statistically significant improvement in NMR fit over energy based refinements. Metrics other than NMR agreement indicate that NMR refinement does not introduce errors with no significant changes observed in atom positions or diffraction patterns. However, refinement does change bond lengths by more than experimental uncertainty with most bond types become shorter than diffraction values. Although this decrease is small (1–4 pm), it significantly alters computed 15N tensors. The NMR refinement was further evaluated by refining two tripeptides. These structures rapidly converged and achieved an NMR agreement equivalent to benchmark values. To ensure accurate comparisons, a complete atomic structure of the tripeptide AGG was determined by single crystal neutron diffraction at 0.58 Å resolution, allowing unambiguous determination of all hydrogen positions. To verify that all NMR refinements represent genuine improvements rather than artifacts of DFT methods, an independent approach was included to evaluate the final NMR refined coordinates. This analysis employs cluster methods and the PBE0 functional. The unusually small 15N NMR root-mean-square error of the final refined structures (3.6 ppm) supports the conclusion that the changes made represent improvements over both diffraction coordinates and lattice-including DFT energy refined coordinates. [ABSTRACT FROM AUTHOR]

Four novel indole thiosemicarbazone derivatives, 1-(indole-2-methylene)-4-substituted-thiosemicarbazides, were synthesized via a one-step reaction by introducing substituents with different conjugacy (methyl, ethyl, cyclohexyl, phenyl). Different from the traditional Schiff-base photochromic compounds, these compounds in this work present dual response signals to UV light, and they exhibit not only reversible solid-state photochromic behavior but also aggregation-induced emission (AIE) characteristics. Furthermore, the structure–activity relationships were revealed by experimental studies, and their photochromism and fluorescence emission were enhanced efficiently with the increase of the conjugation. Furthermore, based on the single crystal structure, FT-IR spectra and theoretical calculations, the proposed photochromic mechanism originates from the intermolecular proton transfer between the thio–keto and thio–enol configurations, and the AIE property is closely related to the restriction of intramolecular rotation. Furthermore, the picture of anti-counterfeiting suggests that the dual responses of these compounds are extremely suitable for multiple encryptions. This work enriches the AIE system and provides a reference for constructing excellent multi-photoresponsive materials. [ABSTRACT FROM AUTHOR]

In this paper, a new high-pressure (HP) polymorph of the otherwise known oxyfluoride K2MoO2F4 is presented. The crystal structure was determined by use of single-crystal X-ray diffractometry and its features are described in detail herein. HP-K2MoO2F4 crystallizes in the monoclinic space group C2/m (no. 12) with the cell parameters a = 13.8579(5), b = 5.8109(2), c = 6.9442(3) Å, β = 90.36(1)°, V = 559.18(4) Å3, and Z = 4 at T = 301(2) K. Bond valence (BV) and charge distribution (CHARDI) calculations were carried out to support the assignment of oxygen and fluorine to the various anion positions and Madelung part of lattice energy (MAPLE) calculations were used to validate the structure model. Infrared spectroscopy provided further information on the structure and water content of the inseparable side phase. [ABSTRACT FROM AUTHOR]

In this paper, we present the synthesis and characterization of a Cl-bearing member of the phosphate family of compounds with a tetragonal crystal structure and similar topology in the basic projection. The title compound was obtained under hydrothermal conditions and its crystal structure was determined by single crystal low temperature X-ray diffraction. The structure of NaCo7.38(PO4)4Cl4 is formed with CoO4Cl2 octahedra sharing faces and assembled into eight-component ring clusters with a very short Co–Co distance of 3.014 Å. These clusters are linked in a three-periodic network via vertex-bridge contacts of adjacent octahedra and PO4 tetrahedra. Na atoms occupy the open channels of the framework. The structure is discussed as a derivative of cubic sulphohalite, Na6(SO4)2ClF, with the symmetry lowering from the widespread Fm3¯m space group of sulphohalite to the tetragonal acentric space group I4¯2m in our case; these space groups are symmetrically related by subordination "group → subgroup". Theoretical calculations of possible pathways of Na migration through the framework showed that although the structure contains a sufficient number of voids for sodium ions, their migration is limited by the size of the channels. However, the obtained results indicated that the migration of Li+ ions is very likely through a two-periodic network parallel to the ab plane, which means that Li-containing structural varieties of NaCo7.38(PO4)4Cl4 with possible formulae Li5Co2+Co3+3(PO4)4Cl4 or Li4Co3+4(PO4)4Cl4 can possess ionic conductivity. The angle of intracluster Co–O–Co bonds of 105.4° allows us to assume that there is an antiferromagnetic exchange interaction between the Co atoms, and we assume that the intercluster exchange interactions between Co2+/3+ ions through the intermediate PO4 groups are also probable. [ABSTRACT FROM AUTHOR]

This paper reports three new crystallographically characterized europium complexes with composition as follows: [Eu(fod)3(L1)] (1), [Eu(fod)3(L2)] (2) and [Eu(fod)3(L3)] (3) {L1 = benzimidazole (bzi), L2 = 4,7-diphenyl-1,10-phenanthroline (bath), L3 = 2-(2-pyridyl) benzimidazole (py-im) and fod = anion of 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedione (Hfod)}. The single crystal (SC) XRD analysis shows that complex 1 is seven-coordinated while complexes 2 and 3 are eight-coordinated with the geometrical structures of a mono-capped octahedron and a trigonal dodecahedron, respectively. The NMR spectra of the complexes validate the SC-XRD results in solution. The complexes are stable in solution as no dissociation of any ligand was observed in the NMR spectra of the complexes. The photophysical properties of the complexes in solution, solid state, and PMMA thin films were studied. The hypersensitive transition 5D0 → 7F2 dominates the emission spectra in all phases, showing the highly asymmetric environment around the Eu(III) ion. The bath ligand is found to be the best sensitizer of the Eu ion and hence complex 2 shows the strongest luminescence properties with the highest absolute quantum yield among the three complexes. The CIE coordinate analysis shows that pure red-luminescence is emitted by the Eu complexes in the solid state since the coordinates found in this phase are closer to the standard NTSC 1987 values. The optical band gaps were determined for the complexes and the observed values suggest that the complexes can have possible applications in the field of semiconductor materials. [ABSTRACT FROM AUTHOR]

Lanthanide luminescence is characterised by "forbidden" 4f–4f transitions and a complicated electronic structure. Our understanding of trivalent lanthanide(III) ion luminescence is centered on Eu3+ because absorbing and emitting transitions in Eu3+ occur from a single electronic energy level. In Sm3+ both absorbing and emitting multiplets have a larger multiplicity. A band arising in transitions from the first emitting state multiplet to the ground state multiplet will have nine lines for a Sm3+ complex. In this study, high-resolution emission and excitation spectra were used to determine the electronic energy levels for the lowest multiplet and first emitting multiplet in four Sm3+ compounds with either tricapped trigonal prismatic TTP or capped square antiprismatic cSAP coordination polyhedra but different site symmetry. This was achieved by the use of Boltzmann distribution population analysis and experimentally determined transition probabilities from emission and excitation spectra. Using this analysis it was possible to show the effect of changing three oxygen atoms with three nitrogen atoms in the donor set for two compounds with the same coordination polyhedra and site symmetry. This work celebrates the 40th anniversary of Kirby and Richardson's first report of [Eu(ODA)3]3− luminescence. [ABSTRACT FROM AUTHOR]

Tetrahydrocurcumin (THC), one of the active metabolites of curcumin, possesses pharmacological activities similar to those of curcumin, such as hypoglycemic, hypolipidemic and antioxidant effects. However, poor water solubility of THC leads to unfavorable absorption, which limits its application. The aim of this study was to improve the solubility of THC through cocrystallization. Five cocrystals of THC with L -proline (THC– L -PRO), D -proline (THC– D -PRO), DL -proline (THC– DL -PRO), 4,4′-bipyridine (THC–BPY), and betaine (THC–BTN) were discovered for the first time using liquid-assisted grinding. Single crystal structures of all THC co-crystals were analyzed and comprehensive characterization was performed through PXRD, thermal analysis, DVS and FT-IR. Dissolution studies were further conducted on two edible cocrystals THC– L -PRO and THC–BTN, and THC– L -PRO exhibits the highest apparent solubility compared with THC–BTN and the raw material. Moreover, THC-form II was found in THC– L -PRO dissolution experiments, and subsequently, the melt crystallization method was used to obtain the pure form of THC-form II. THC-form II was characterized for its physicochemical properties and the result of the dissolution experiment showed that it has better solubility compared to THC-form I. [ABSTRACT FROM AUTHOR]

A ruthenium nitrosyl complex of formula [RuII(fluorene(C6)CH2O-terpy)(bipy)(NO)]3+ (AC) in which fluorene(C6) is the 9,9-dihexylfluorene, terpy the 2,2′;6′,2′′-terpyridine, and bipy the 2,2′-bipyridine is presented with its related [RuII(MeO-terpy)(bipy)(NO)]3+ (C) and 9,9-dihexylfluorene 2-hydroxymethylfluorene (A) building blocks. The reference complex C undergoes NO release capabilities under irradiation at λ = 365 nm. The effect of the introduction of the fluorescent A antenna within the resulting AC complex is discussed both experimentally and theoretically. The importance of the encaging parameter defined as φAC·IAC, in which IAC is the quantity of light absorbed by AC and φAC the quantum yield of NO release is evidenced and found to be concentration dependent. The conditions of optimization of the antenna approach to maximize φAC·IAC are discussed. The crystal structure of [RuII(fluorene(C6)CH2O-terpy)(bipy)(NO2)](PF6), the last intermediate in the synthesis of AC is also presented. [ABSTRACT FROM AUTHOR]

Schiff bases are the most widely used class of molecules and their metal complexes are utilized as medicinally important scaffolds due to their versatile biological profile. So herein, we have reported the synthesis of N2O2-type tetradentate Schiff bases {N,N′-(ethylene)bis(salicylideneimine) (1a) and N,N′-(o-phenylene)bis(salicylideneimine) (1b)} and their Ni(II) complexes, dimeric N,N′-(ethylene)bis(salicylideneiminato)nickel(II) (2a) and N,N′-(o-phenylene)bis(salicylideneiminato)nickel(II) (2b), and their characterization using CHN analysis, ESI-MS and XRD techniques. The interaction of ligands 1a–b and complexes 2a–b with the biomolecules {calf thymus DNA (CT-DNA) and bovine serum albumin (BSA)} has been investigated via electronic absorption and fluorescence spectroscopy. The results show that ligands 1a–b and complexes 2a–b can bind to CT-DNA via a minor groove mode. Moreover, the fluorescence quenching mechanism between ligands 1a–b and complexes 2a–b and BSA is a static quenching process. The results showed that the interaction between ligands 1a–b and BSA is driven by hydrogen bond and van der Waals interactions, while the hydrophobic forces stabilized the interaction between complexes 2a–b and BSA. Additionally, the r values of ligands 1a–b and complexes 2a–b (1a = 0.53 nm, 1b = 0.59 nm, 2a = 0.57 nm and 2b = 0.71 nm) calculated using FRET theory suggested that the distance between ligands 1a–b and complexes 2a–b and BSA is quite close. The radical scavenging activity of ligands 1a–b and complexes 2a–b was determined in terms of EC50, using the DPPH method. The cytotoxicities of ligands 1a–b and complexes 2a–b against human breast cancer (MCF-7) and lung cancer (A549 and H1299) cell lines and healthy lung bronchial (BEAS-2B) and breast epithelial (MCF-10A) cell lines were investigated. Molecular docking simulations were carried out to correlate the data with the experimental findings. The binding interaction of ligands 1a–b and complexes 2a–b with the B-DNA and 1M17 was generated and predicted using Autodock 4.2 software. The results indicated that ligands 1a–b and complexes 2a–b bind at the minor groove of DNA through intercalation and at the active side of the EGFR tyrosine kinase. [ABSTRACT FROM AUTHOR]

A new organic–inorganic hybrid molecule, cyclohexyl ammonium dihydride triphosphate, was synthesized at room temperature with slow evaporation, yielding a new triphosphate with the formula HO10P3·(C6H14N)4·2(H2O) using a chemical ion exchange process. Detailed crystal structure analysis by single crystal X-ray diffraction has been reported, and different units in the molecular arrangement are held together by N–H⋯O and O–H⋯O hydrogen bonds to form a three-dimensional structure. Spectroscopic analysis including FT-IR, UV-visible, and ATD/ATG were also employed to characterize the complex. Explorations of impedance spectroscopy on HO10P3·(C6H14N)4·2(H2O) show fascinating electrical behavior, which reveals that the triphosphate component can be used as an electronic chip and under certain conditions; this semiconductor can act as a conductor, which can be considered as a pure element. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measurements were performed. Electronic structure calculations were performed using the ωB97XD/def2tzvp method. In the thermodynamic study, the Gibbs free energy of formation, interaction energy, and enthalpy of formation were calculated. NBO charges and FMO study show the nature of the donor–acceptor part in the complex. Quantum theory of atoms in molecule (QTAIM) is employed to unfold the noncovalent interactions present in the complex. Optical and nonlinear optical (NLO) properties are determined by calculating polarizability and hyperpolarizability. Hirshfeld surface (HS) analysis reveals the strength and nature of elemental interactions in crystal packing. Theoretical findings are compatible with the experimental study. [ABSTRACT FROM AUTHOR]

Six new coordination polymers (CPs) of cadmium based on an extended anilate-type ligand, 4,4′-(1,4-phenylenebis(azanylylidene))bis(3,6-di-tert-butyl-2-hydroxycyclohexa-2,5-dienone) (H2L), have been synthesized. The series of coordination polymers includes [Cd(L)(DMF)] (1), 1D-CP [Cd(L)(dipy-1)]·2DMF (2A) and 2D-CP [Cd(L)(dipy-1)]·DMF (2B), [Cd2(L)2(dipy-2)(DMF)2] (3), [Cd(HL)(CH3COO)(dabco)] (4) and [Cd(L)(ur)2]·(H2L) (5) (where L – deprotonated form of H2L, DMF – N,N′-dimethylformamide, dipy-1 – 4,4′-trimethylenedipyridine, dipy-2 – 4,4′-dipyridyl, dabco – 1,4-diazabicyclo[2.2.2]octane, ur – urotropine). The crystal structure and thermal decomposition of 1D- and 2D-coordination polymers are reported. The structural diversity of the synthesized compounds was found to depend on the additional neutral donor ligands in the cadmium coordination sphere. Thus, the introduction of the flexible N-donor ligand dipy-1 into the cadmium coordination sphere leads to the formation of two types of coordination polymers (1D and 2D). The use of the rigid ligand dipy-2 promotes the formation of "honeycomb" 2D-CPs. The use of shorter N-donor ligands dabco and ur leads to linear derivatives in which the ligands being coordinated by cadmium don't act as "crosslinkers" of the chains in the network. [ABSTRACT FROM AUTHOR]

Development of multifunctional organic materials is an area of intense research interest in organic materials chemistry. This study reports the synthesis, crystal structure elucidation and investigation of multiple properties of E-3-pyridylvinyl benzoxazole (3-PVBO) and its methylated analogue, 3-MPVBO. With Z′ = 2, 3-PVBO belongs to a rare class of crystals for which Z′ > 1. Upon methylation, fascinating material properties were observed. [3-MPVBO]I exhibited strong emission spectra and readily available redox states. It exhibited stronger emission at 474 nm, with a larger Stokes shift of 8900 cm−1, than the emission of 3-PVBO at 386 nm, with a Stokes shift of 5450 cm−1. Upon exposure to UV light, crystals of 3-PVBO underwent a solid-state photodimerization reaction in a head-to-tail fashion (HT), leading to the formation of the HT-rctt isomer of the dimer, i.e., 1,3-bis(benzoxazole)-2,4-bis(3-pyridyl)cyclobutane (PBOCB). Herein, the crystal structure, solid-state photoreactivity, and multiple material properties, e.g., photophysical and electrochemical properties, are presented. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis, crystal structure, and antibacterial activity of a new Ni(II) complex derived from the N, O donor (E)-2,4-dibromo-6-(2-(1-phenylethylimino) ethyl) phenol ligand. Both the ligand and the complex were characterized by employing FT-IR, UV-Visible, and fluorescence spectroscopy as well as single-crystal X-ray diffraction studies. The crystallographic results reveal that the complex crystalizes in the monoclinic unit cell with the space group C2, and the coordination environment around the Ni centre consists of NiN2O2 donor sites exhibiting a highly distorted tetrahedral geometry. The oxidative assay of DPPH (α,α-diphenyl-β-picrylhydrazyl) was used for evaluating the radical scavenging activity or antioxidant properties of the complex in terms of IC50 values (50% inhibition); it was observed that the complex showed reasonable antioxidant activities with ascorbic acid (AA) as the standard. Detailed interaction studies with calf thymus (CT) DNA and bovine serum albumin (BSA) were performed through various spectroscopic and theoretical approaches and indicated that the complex has promising binding capability with both the systems. Comprehensive biological studies were performed and showed that the complex exhibits notable antibacterial activity against Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) by interfering with its cell wall integrity. Microscopic imaging confirmed cellular abnormalities, such as alterations in the cell shape, size, and quantity. Molecular docking analyses also provided insights into the activities of the complex. In contrast, the complex displayed minimal growth inhibition properties against Gram-negative Klebsiella pneumoniae (KP) even at higher complex concentration, indicating that the specific inhibition activity of the complex is only against Gram-positive MRSA. Moreover, based on optical density readings, the results demonstrated that the complex exhibited effective antibacterial activity against MRSA with an MIC value between 34 and 36 μg ml−1, whereas the MIC value of standard cefoxitin is >70 μg ml−1. Thus, our complex demonstrated better antibacterial activity than the conventional antibiotic. [ABSTRACT FROM AUTHOR]

This article presents crystal structures of chalcogenadiazolecarboxylic acids bearing both a hydrogen and a chalcogen bond donor. The selected molecules varied in the size of the aromatic unit, the chalcogen atom and/or the position of the carboxyl group in the core structure. The most common synthons in their lattice are R 22 (8) self-complementary acid dimers or four-membered [Ch⋯N]2 rings. Supramolecular synthons where chalcogenadiazole moieties interact with the carboxyl group were also identified. Both ESP calculations and experimental data showed that all the studied molecules adopted flat conformations, but only in the case of three crystal structures were flat sheets observed. To assess the contribution of hydrogen and chalcogen bonds to the stabilization of the crystal structure, crystal lattice energy calculations were performed. [ABSTRACT FROM AUTHOR]

Potassium manganese fluoride phosphate, KMnPO4F, has been obtained through mild hydrothermal synthesis and characterized by scanning electron microscopy, microprobe analysis and X-ray diffraction. The compound possesses an orthorhombic symmetry and chiral space group P212121 with a = 4.7884(2), b = 9.0172(4), c = 9.5801(4) Å, and Z = 4. Its crystal structure is composed of Mn3+O4F square pyramids sharing vertices with PO4 tetrahedra. This anionic framework is neutralized by K+ cations. As the temperature decreases, a short-range correlation state (Tmax ∼ 35 K) of KMnPO4F is formed, followed by the establishment of antiferromagnetic (AFM) long-range order at TN = 25 K. The latter is marked by sharp λ-type anomalies in both Fisher's specific heat d(χkT)/dT and heat capacity Cp. Pulsedmagnetic field measurements on the single crystals identify the a axis as the easy magnetic axis and reveal a spin-flop transition at μ0Hspin-flop = 19 T. Density functional theory indicates that in variance with the three-dimensional network of KMnPO4F, it is a two-dimensional Ising magnetic system represented by buckled layers of integer spins S = 2 of Mn3+ ions. The strongest AFM exchange interaction, J1 ∼ -13 K, couples Mn3+ ions into linear chains running along the a axis. The chains themselves are ferromagnetically connected (J3 ∼ -4 K) within the ab plane. The interplane AFM exchange interaction (J2 ∼ -1 K) is weak and frustrated. [ABSTRACT FROM AUTHOR]

Nine lanthanide-organic frameworks [Ln(L)1.5(H2O)3] (1-Ce, 2-Dy, 3-Eu, 4-Gd, 5-Ho, 6-Nd, 7-Pr, 8-Sm, and 9-Tb; H2L = 4,4'-(1,2-dihydroxyethane-1,2-diyl)dibenzoic acid) have been synthesized under solvothermal conditions. Single-crystal X-ray diffraction analyses show that compounds 1-9 are isomorphic, in which each Ln atom is linked by L ligands to form a 3D framework with an unprecedented 4,4,6-connected topology. All these compounds have excellent solvent stability and can remain stable in boiling water for up to a week. Moreover, these compounds exhibit metal-dependent luminescence and magnetic properties. 3-Eu and 9-Tb exhibit relatively good fluorescence properties, 4-Gd shows ferromagnetic coupling, and the other compounds present antiferromagnetic coupling. [ABSTRACT FROM AUTHOR]

Two new nickel(II) complexes, namely Ni(L1)2 (1) and Ni(L2)2·CH2Cl2(2) were obtained by reacting nickel(II) acetate tetrahydrate with the benzothiadiazole Schiff base ligands HL1 = 2-[4-(2,1,3-benzothiadiazole)imino]methyl-phenol or HL2 = 2-[(2,1,3-benzothiadiazol-4-ylimino)methyl]-6-methoxyphenol in the presence of Et3N. The tridentate NNO chelate ligands induce a distorted octahedral environment around the nickel(II) ions. Single crystal X-ray diffraction analysis reveals elongated Ni–N bonds with the nitrogen atom of the benzothiadiazole ring in both complexes. Intermolecular hydrogen bonds and π–π stacking interactions create two-dimensional and three-dimensional supramolecular arrays, respectively, for complexes 1 and 2. Magnetic susceptibility and high-field electron paramagnetic resonance measurements show the presence of significant magnetic anisotropy, with an axial distortion parameter D of −8–−10 cm−1. [ABSTRACT FROM AUTHOR]

In this study, the structural, electronic, and vibrational properties of the thinnest crystal structure that can be obtained by thinning bulk Cd down to a monolayer are investigated by performing first-principles calculations. Total energy optimization and dynamic stability calculations reveal that the single layer crystal structure has a hexagonal unitcell with a two-atomic basis where alternating layers are formed by trigonal arrangements of Cd atoms. Softening occurs with decreasing zone center optical phonon frequencies as a result of structural relaxation when going from a bulk to a single layer (SL) structure. It is also shown that the thinnest structure obtained from bulk Cd crystals maintains its metallic features despite the dimensional crossover. In addition, it is predicted through calculations that the SL Cd crystal strongly interacts with oxygen and that the oxidized regions even undergo chemical transformation to form a CdO crystal. In the double-layer CdO crystal resulting from the oxidation of individual Cd layers, the layers are connected to each other with partially covalent bonds, and this structure is a semiconductor with a band gap of 2.10 eV. On the one hand, the robust metallic structure of the thinnest possible Cd crystal provides flexibility for its use in nanoscale applications, on the other hand, the fact that its electronic properties can be changed by oxidation is important for optoelectronic device applications. [ABSTRACT FROM AUTHOR]

Designing and discovering negative thermal expansion (NTE) materials is important in precisely controlled thermal expansion devices. In this work, the NTE of a cubic metal fluoride, ReO3-type VF3, was predicted by density functional theory within the quasi-harmonic approximation. These results reveal that cubic VF3 displays a negative thermal expansion behavior below 200 K, and the predicted minimum negative thermal expansion coefficient is approximately −6.4 × 10−6 K−1 at 80 K. The negative thermal expansion was mainly dominated by the prominently negative Grüneisen parameter situated at M(0.5,0.5,0) and R(0.5,0.5,0.5). The underlying mechanism was attributed to the anisotropic F atom vibration, where the amplitude of transverse vibration perpendicular to the V–F–V connection was much larger than that of the vibration along the parallel V–F–V direction. This research provides a good understanding of the relationship between NTE and crystal structure. [ABSTRACT FROM AUTHOR]

To improve the solubility, a series of novel pharmaceutical salts prepared by ciprofloxacin as the active pharmaceutical ingredient (API) and phthalic acid and its isomers or substituted benzene carboxylic acids as the coformers were synthesized and structurally characterized. The solubility of these pharmaceutical salts is enhanced compared to the parent APIs. The solubility values of three benzene dicarboxylates of ciprofloxacin in phosphate buffer (pH = 6.8) are 20.5 times, 21.8 times, and 2.0 times that of ciprofloxacin, respectively. In particular, the solubility of ciprofloxacin salicylate hydrate has been dramatically improved (up to 349 times) in both neutral (1.45 and 1.32 mg mL−1 at pH 6.4 and 6.8, respectively) and acidic (13.96 mg mL−1 at pH 1.2) environments. Computational chemistry was employed to analyze the solubility of ciprofloxacin salts and elucidate the mechanisms underlying their enhanced solubility. [ABSTRACT FROM AUTHOR]