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In this work, solid state characterization and the investigation of the thermal behavior of cis-1,3 and trans-1,3 cyclohexanediol isomers were carried out. A plastic crystal phase could be identified only for the trans isomer, which vitrifies on cooling, while for the cis isomer two monotropically related ordered crystal phases have been found. These results allow gaining of comprehensive knowledge of the six cyclohexanediol isomers' plastic crystal forming ability; plastic crystal phases were observed for three of the six cyclohexanediol derivatives, coinciding with the axial–equatorial isomers cis-1,2, trans-1,3 and cis-1,4-cyclohexanediols. The molecular structure of all the possible conformations of the isolated molecules of the six cyclohexanediol isomers was optimized at the MP2/aug-cc-pVDZ level of theory. The axial–equatorial isomers have several conformers with relevant abundance, which can have greater entropy of mixing, which may have a role in stabilizing the disordered plastic phases. For trans-1,4-cyclohexanediol, the conformer population breakdown is 66.4% bi-equatorial and 33.6% bi-axial. The bi-axial conformations of trans-1,4-cyclohexanediol are preserved in the solid forms. The Hirshfeld surface analysis of the parent anisotropic phase was confirmed as a valuable tool to assess the plastic crystal forming ability in this family of compounds, and the asphericity parameter to be a good indicator. The fingerprint plots highlight frequent intermolecular H–H close contacts for cis-1,3-cyclohexanediol, also found in other non-plastic crystal former cyclohexanediols. [ABSTRACT FROM AUTHOR]

The crystal structure of (μ 3 -oxo)hexakis(cyanoacetato-κO,O′)(cyanoacetato-κO)diaquatriiron(III) cyanoacetic acid shows the formation of trinuclear complexes in a hydrogen-bond network that bonds all the molecules in a 3D arrangement. For this complex, within whose clusters the whole magnetic interaction takes place, 57 Fe Mössbauer spectroscopy shows that the Fe cations are in the S = 5/2 state in the temperature range 2–295 K. The asymmetric broadening of the absorption peaks below 80 K is consistent with strong antiferromagnetic interactions between the metal spins. The magnetization measurements also show the antiferromagnetic character of the spin ensemble and an S T = 1/2 magnetic ground state typical of triangular systems with similar J between Fe-Fe pairs. [ABSTRACT FROM AUTHOR]

m-Anisic acid is generally recognized as a safe (GRAS) flavouring substance. Its GRAS status and the functional groups present in the molecule make it an interesting candidate for pharmaceutical co-crystallization studies. The knowledge of m-anisic acid crystalline structure/polymorphic behaviour is important information for its applications. In this work, a crystalline structure of m-anisic acid form I, T = 105 °C, was solved by X-ray diffraction: monoclinic, space group P2/ n, with a = 13.8075(5) Å, b = 5.0221(2) Å, c = 21.4455(8) Å, β = 99.325(3)°, Mr = 331.37, V = 1467.44(10) Å, Z = 8 and R = 0.0395 (CCDC No. 985352). A recent paper by Raffo et al. (J Mol Struct 1070:86-93, ) (CCDC No. 985637) also resolved the structure, and within experimental error, the two structures are equal. The molecular flexibility of m-anisic acid results in the presence of two conformers in the unit cell, a rare case of conformational isomorphism. These two conformers were found by ab initio calculations to differ in energy by 4.9 kJ mol. Solid samples were generated by crystallization from solutions and by melt cooling. Using a multidisciplinary approach involving thermal analysis (DSC, PLTM), infrared spectroscopy and X-ray powder diffraction, a new monotropic solid form II, T = 94 °C, was identified and characterized. Polymorph II slowly transforms into polymorph I at room temperature. [ABSTRACT FROM AUTHOR]

Synthesis, structure and properties of two alkali-lanthanide heterometallic coordination polymers with the stoichiometric formula [M(OH)(HO)Ln(NO)] (where M is Na and Ln, Er or Yb) are reported. They crystallize in the monoclinic P2/ c space group with very similar cell parameters: a = 15.8777(19) Å, b = 13.4173(18) Å, c = 13.3515(17) Å, β = 93.585(9)º, and V = 2838.8(6) Å for Er(III) and a = 15.8756(5) Å, b = 13.3707(4) Å, c = 13.3083(4) Å, β = 93.584(2)º, and V = 2819.40(15) Å for the Yb(III) polymer. The main findings in the structures of the new compounds are their isomorphism (due to the similarity between erbium and ytterbium ionic radii) and the coexistence in both of highly aqueous coordinated [Na(OH)(HO)] and [Ln(NO)] units. The luminescence measurements in the near infrared region after excitation at different wavelengths have confirmed the deleterious effect (quenching) of OH and HO groups on the emission (intensity and lifetime) of both erbium(III) and ytterbium(III) and the very weak optical absorption of lanthanides. Magnetic measurements show a paramagnetic behavior of the lanthanide centers. Graphical Abstract: Two new isostructural alkali-lanthanide coordination polymers, [Na(OH)(HO)Er(NO)] and [Na(OH)(HO)Yb(NO)], have been synthesized and characterized by X-ray diffraction. Their photoluminescent and magnetic properties are presented.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

X-ray diffraction and semiempirical methods have been used to investigate the structures of novel erbium(III) [Er(od) 3 (N,N-donor)] complexes, where od = 2,4-octanedionate and N,N-donor = 2,2′-bipyridine (bipy), bathophenanthroline (bath) or 5-nitro-1,10-phenanthroline (5NO 2 phen). Structural characteristics for these ternary complexes were also obtained by FTIR spectra. Subsequently, the visible and near-infrared luminescence properties of the compounds have been studied. Upon ligand excitation, the complexes show strong near-infrared luminescence at 1530 nm due to antenna effect . These erbium(III) complexes can potentially be applied to polymeric erbium-doped optical amplifiers, planar waveguides or infrared OLEDs. [ABSTRACT FROM AUTHOR]

Abstract The anhydrous hybrid material (C 6 H 10 N 2) (ClO 4) 2 has been synthesized by the slow evaporation method. X-ray diffraction on a single crystal shows that this compound crystallizes in the monoclinic system with the centrosymmetric space group P 2 1 / c. The 2D supramolecular network is stabilized by N H⋯O interactions whereas the van der Waals contacts play a key role in the consolidation of the 3D packing as verified by Hirshfeld surface analysis in combination with 2D fingerprint plots. The 13C CP-MAS NMR spectrum is in agreement with the X-ray structure. DFT calculations allowed the attribution of the NMR peaks. FT-IR spectrum confirms the presence of various functional groups in the synthesized material. The thermal stability, phase transition and degradation, of this material has been studied using simultaneous TG-DTA. The gap between the frontier molecular orbitals is about 1.53 eV suggesting that the studied compound is a semiconducting material. Highlights • New anhydrous hybrid perchlorate was synthesized and characterized. • The X-ray crystal structure of this new hybrid compound was elucidated. • Intermolecular interactions were analyzed by Hirshfeld surface analysis. • Thermal stability of the studied compound was carried out by TG-DTA curves. • Frontier molecular orbitals study shows a low band gap suggesting a semiconductor character. [ABSTRACT FROM AUTHOR]

Highlights: [•] Synthesis and structure of 6-aminoquinolinium iodide monohydrate is reported. [•] UV–vis absorption and fluorescence spectra are reported. [•] SHG and THG signals measured with the Maker fringes technique. [•] Hyperpolarizabilities calculated with the DFT and MP2 methods. [•] Behaviour of hybrid functionals corrected with ESP charges. [Copyright &y& Elsevier]

Abstract: Several 4-arylidene-2-phenyl-5(4H)-azlactones have been synthesized via Erlenmeyer method. The synthesized compounds have been characterized on the basis of systematic spectral studies (IR, 1H NMR, 13C NMR, and MS). The compound (4Z)-4-(3,5-dimethoxybenzylidene)-2-phenyl-1,3-oxazol-5(4H)-one, C18H15NO4, (5), crystallizes in the orthorhombic system, space group P212121 , with a =5.6793(3)Å, b =15.2038(7)Å, c =17.6919(10)Å, Mr =309.31, V =1527.64(14)Å3, Z = 4 and R =0.0547. The compound (4Z)-2-phenyl-4-(3,4,5-trimethoxybenzylidene)-1,3-oxazol-5(4H)-one, C19H17NO5, (6) crystallizes in triclinic geometry with space group P-1, having unit cell parameters a = 7.3814(3)Å, b =8.1446(3)Å, c =13.9845(5)Å, α = 86.918(3), β = 83.314(2), γ = 82.462(3), Mr =339.34, V = 827.16(5)Å3, Z = 2 and R =0.0433. The DFT calculations of compounds (5) and (6) have been carried out to ascertain the stability of Z-conformer. The in vitro antimicrobial activity of all the compounds (1–6) was evaluated by the disk diffusion method against gram +ve and gram −ve microorganism and fungal strains. The MIC of the synthesized compounds was determined by agar well diffusion method in 96-well microtiter plate. All the synthesized compounds were also screened for their free radical scavenging activity by DPPH method. [Copyright &y& Elsevier]

An efficient procedure for the one-pot synthesis of 4-arylmethylene-3- methylisoxazol-5-ones from ethyl acetoacetate, hydroxylamine hydrochloride, and various aromatic aldehydes using sodium acetate as a safe, clean, and green catalyst in ethanol is reported. This simple, synthetic and eco-friendly approach resulted in a remarkable improvement in the synthetic efficiency (90–95% yield), high purity, minimizing the production of chemical wastes without using highly toxic reagents for the synthesis and, more notably, it improved the selectivity for (Z)-isoxazol-5-ones derivatives. By performing DFT calculations, it was found that the (Z)-isomer of compound 4a is stabilized by 6.54 kcal mol−1 more than the (E)-isomer and The Z -isomer of 4g is also more stable, by 4.36 kcal mol−1. All of the compounds were tested for interaction study with ct-DNA. Compounds 4a and 4b shows the most effective binding affinity with ct-DNA in comparison of other synthesized compounds. The interaction studies of compound 4a and 4b with ct-DNA showed groove binding interaction (non-intercalation) with both compounds. On the other hand, compound 4a (K = 5.9 × 105 M−1) shows higher binding affinity to the ct-DNA than compound 4b (K = 4.5 × 105 M−1). The molecular modeling results illustrated that compound 4b strongly binds to groove of DNA by relative binding energy of docked structure −6.35 kcal mol−1. Docking model of compounds 4a and 4b with ctDNA. Image 1 • Eco-friendly synthesis of Z- Isoxazol-5(4H)-ones derivatives was done using the sodium acetate. • The Z-isomer of Isoxazol-5(4H)-ones derivatives 4a is more stable by 6.54 kcal mol−1 thus explaining the crystallization of this particular form. • On the other hand, the compound 4a (K = 5.9 × 105 M−1) shows higher binding affinity to the ct-DNA. • Docking results showed that 4b strongly binds to ct-DNA groove by relative binding energy of docked pose −6.35 kcal mol−1. [ABSTRACT FROM AUTHOR]