Substituent Effects in 3,3' Bipyrazole Derivatives. X-ray Crystal Structures, Molecular Properties and {DFT} Analysis.

The single crystal X-ray structure of new 1,1'-bis(2-nitrophenyl)-5,5'-diisopropyl-3,3'-bipyrazole, 1, is triclinic P , a = 7.7113(8), b = 12.3926(14), c = 12.9886(12) Å, a = 92.008(8), ß = 102.251(8), γ = 99.655(9)°. The structural arrangement is compared to that of 5,5'-diisopropyl-3,3'-bipyrazole, 5, whose single crystal structure is found tetragonal I41/a, a = b = 11.684(1), c = 19.158(1) Å. The comparison is also extended to the structures previously determined for 1,1'-bis(2-nitrophenyl)-5,5'-propyl-3,3'-bipyrazole, 2, 1,1'-bis(4-nitrophenyl)-5,5'-diisopropyl-3,3'-bipyrazole, 3, and 1,1'-bis(benzyl)-5,5'-diisopropyl-3,3'-bipyrazole, 4. Density Functional Theory (DFT) calculations are used to investigate the molecular geometries and to determine the global reactivity parameters. The geometry of isolated molecules and the molecular arrangements in the solid state are analyzed according to the nature of the groups connected to the bipyrazole core.

Structural and Vibrational Study of CsSbGe3O9, a New Germanate in the ASbGe3O9 Family (A = Alkali Metal).

The germanate CsSbGe3O9, grown spontaneously via the high-temperature solution method from Cs2Mo4O13 used as a flux, crystallizes in the orthorhombic system with a = 12.3636(2), b = 13.8521(2), c = 31.4824(5) Å, and V = 5391.73(2) Å3. Its structure, determined from single-crystal X-ray diffraction data, is most probably noncentrosymmetric despite our choice to report it in the centrosymmetric maximal supergroup Pnma D2h16 (no. 62) in which agreement factors R1 = 0.0371 and wR2 = 0.0706 (all data) were obtained. The unit cell contains 24 formulas CsSbGe3O9. The three-dimensional network is built up with regular germanate tetrahedra at nine crystallographically independent Ge sites. The Sb atoms (four independent positions) adopt octahedral coordination with O atoms, and the Cs+ cations are located in the channels of the 3-D network. A more in-depth analysis of the structure of CsSbGe3O9 is carried out in the light of the structures previously determined for the compounds ASbGe3O9 (A = K, Rb) having the same chemical formula but significantly different atomic arrangements. The structural characteristics are discussed related to literature and the nature of the monovalent cation A+.

Novel ß-keto-enol Pyrazolic Compounds as Potent Antifungal Agents. Design, Synthesis, Crystal Structure, DFT, Homology Modeling, and Docking Studies.

A new family of promising inhibitors bearing ß-keto-enol functionality with greatly improved pharmacophore properties has been prepared. Herein, a series of novel derivatives of ß-keto-enol group embedded with pyrazolic moiety has been designed and synthesized via a one-step procedure using mixed Claisen condensation in the attempt to develop potential antifungal agents. The structures of the synthesized compounds were confirmed by elemental analysis, FT-IR, ESI/LC-MS, and 1H and 13C NMR. In addition, X-ray diffraction analysis (XRD) was used to determine the single crystal structure of compound 10. All of the new compounds have been evaluated for their in vitro antifungal and antibacterial activities. Interestingly, the results indicate that most of the compounds display notable antifungal activity close to that of the benomyl fungicide taken as the standard drug. For the most active compound and for benomyl, a correlation has been evidenced between the experimental antifungal activity and the theoretical predictions by DFT calculations and molecular docking against Fgb1 protein.

Synthesis, crystal structure, DFT studies and biological activity of (Z)-3-(3-bromophenyl)-1-(1,5-dimethyl-1H-pyrazol-3-yl)-3-hydroxyprop-2-en-1-one.

BACKGROUND: Nowadays, is emerging a new generation of highly promising inhibitors bearing the ß-ketoenol functionality. The present work relates to the first synthesis, the structure determination, the DFT studies and the use of a new biomolecule designed with a ß-ketoenol group bounded to a pyrazolic moiety. RESULT: A novel ß-ketoenol-pyrazole has been synthesized, well characterized and its structure was confirmed by single crystal X-ray diffraction. The electron densities and the HOMO-LUMO gap have been calculated using the DFT method with BLYP, PW91, PWC functionals and 6-31G* basis set. An evaluation of the molecule stability is provided by a NBO analysis and the calculated Fukui and Parr functions have been used to locate the reactive electrophile and nucleophile centers in the molecule. The synthesized compound, screened for its in vitro antifungal behavior against the Fusarium oxysporum f.sp. albedinis FAO fungal strains, shows a moderate activity with an inhibition percentage of 46%. The product was also tested against three bacterial strains (Escherichia coli, Bacillus subtilis and Micrococcus luteus), but no significant effect was observed against these organisms. CONCLUSIONS: Density functional calculations are used to evaluate the HOMO-LUMO energy gap, the molecular electrostatic potential and to provide a natural bond orbital analysis. The measured antimicrobial activities encourage us to continue searching for other structures, likely to be good antifungal candidates.

X-ray Single Crystal Structure, DFT Calculations and Biological Activity of 2-(3-Methyl-5-(pyridin-2'-yl)-1H-pyrazol-1-yl) Ethanol.

A pyridylpyrazole bearing a hydroxyethyl substituent group has been synthesized by condensation of (Z)-4-hydroxy-4-(pyridin-2-yl)but-3-en-2-one with 2-hydroxyethylhydrazine. The compound was well characterized and its structure confirmed by single crystal X-ray diffraction. Density functional calculations have been performed using DFT method with 6-31G* basis set. The HOMO-LUMO energy gap, binding energies and electron deformation densities are calculated at the DFT (BLYP, PW91, PWC) level. The electrophilic f(-) and nucleophilic f(+) Fukui functions and also the electrophilic and nucleophilic Parr functions are well adapted to find the electrophile and nucleophile centers in the molecule. The title compound has been tested for its DPPH radical scavenging activity which is involved in aging processes, anti-inflammatory, anticancer and wound healing activity. Compound is also found with a significant antioxidant activity, probably due to the ability to donate a hydrogen atom to the DPPH radical.

ß-Keto-enol Tethered Pyridine and Thiophene: Synthesis, Crystal Structure Determination and Its Organic Immobilization on Silica for Efficient Solid-Liquid Extraction of Heavy Metals.

Molecules bearing ß-keto-enol functionality are potential candidates for coordination chemistry. Reported herein is the first synthesis and use of a novel designed ligand based on ß-keto-enol group embedded with pyridine and thiophene moieties. The product was prepared in a one-step procedure by mixed Claisen condensation and was characterized by EA, m/z, FT-IR, (¹H, (13)C) NMR and single-crystal X-ray diffraction analysis. The new structure was grafted onto silica particles to afford a chelating matrix which was well-characterized by EA, FT-IR, solid-state (13)C-NMR, BET, BJH, SEM and TGA. The newly prepared organic-inorganic material was used as an adsorbent for efficient solid-phase extraction (SPE) of Cu(II), Zn(II), Cd(II) and Pb(II) from aqueous solutions and showed a capture capacity of 104.12 mg·g(-1), 98.90 mg·g(-1), 72.02 mg·g(-1), and 65.54 mg·g(-1), respectively. The adsorption capacity was investigated, in a batch method, using time of contact, pH, initial concentration, kinetics (Langmuir and Freundlich models), and thermodynamic parameters (ΔG°, ΔH° and ΔS°) of the system effects.

New nickel gallium boride, B14Ga3Ni27: synthesis and crystal structure.

Crystals of the new compound B(14)Ga(3)Ni(27) were successfully prepared by arc melting of the elements. B(14)Ga(3)Ni(27) crystallizes as a novel structure type in the monoclinic space group P2(1)/m with unit cell parameters a = 8.6859(4) Å, b = 10.7477(4) Å, c = 8.8425(3) Å, ß = 90.707(4)°, and Z = 2. Its structure was solved from single crystal data and refined to R1(F) = 0.0225. The unit cell of B(14)Ga(3)Ni(27) contains boron dumbbells and isolated gallium atoms embedded in a nickel 3D-framework. Its electronic structure, calculated by DFT methods, indicates metallic properties.

Investigation in the binary system Yb-Ga: crystal structure of the Ga-rich compound YbGa3.34.

Compounds within the Yb-Ga binary system were prepared by direct melting of the elements, and their crystal structure was solved from single crystal X-ray diffraction. YbGa(2) crystallizes in the hexagonal system, P6(3)/mmc, a = 4.4527(2), c = 7.1969(3) A, and YbGa(4) is monoclinic, C2/m, a = 6.129(2), b = 6.1096(14), c = 6.097(2) A, beta = 119.05(5) degrees . A new compound of formula YbGa(3.34) was identified in this system, and its crystal structure determined in the orthorhombic Immm space group, a = 4.2049(4), b = 4.3320(5), c = 25.691(3) A. While atoms are fully ordered in YbGa(2) and YbGa(4), partial atomic disorder occurs in YbGa(3.34) where gallium triangular units are found to substitute for some Yb atoms. The electronic structures have been calculated by first principles density functional theory methods using ordered models in supercells. Crystal structures and bonding therein are analyzed on the basis of gallium three-dimensional (3D) anionic networks and are compared with similar compounds. YbGa(3.34) marks the boundary between layered and 3D intergrown gallium frameworks.

Structural versatility of the epsilon-SmGa(x) phase: X-ray, electron diffraction, and DFT studies.

Two new compounds, SmGa(2.67) (hexagonal, P62c, Z = 15, a = 12.861(2), c = 8.4402(8) A) and SmGa(3.64) (orthorhombic, Fmmm, Z = 24, a = 8.493(1), b = 14.912(2), c = 17.080(2) A), have been synthesized and identified in the Sm-Ga system and their crystal structures solved and refined from single-crystal X-ray diffraction. These structures display consistent atomic disorder. Electronic structures have been calculated using first-principle DFT methods with ordered models. Atomic arrangements and bonding are analyzed on the basis of gallium partial anionic networks; they are compared with those of some analogous compounds in the other lanthanide-gallium systems.

Electroactive nanorods and nanorings designed by supramolecular association of pi-conjugated oligomers.

In investigations into the design and isolation of semiconducting nano-objects, the synthesis of a new bisureido pi-conjugated organogelator has been achieved. This oligo(phenylenethienylene) derivative was found to be capable of forming one-dimensional supramolecular assemblies, leading to the gelation of several solvents. Its self-assembling properties have been studied with different techniques (AFM, EFM, etc.). Nano-objects have successfully been fabricated from the pristine organogel under appropriate dilution conditions. In particular, nanorods and nanorings composed of the electroactive organogelator have been isolated and characterized. With additional support from an electrochemical study of the organogelator in solution, it has been demonstrated by the EFM technique that such nano-objects were capable of exhibiting charge transport properties, a requirement in the fabrication of nanoscale optoelectronic devices. It was observed that positive charges can be injected and delocalized all along an individual nano-object (nanorod and nanoring) over micrometers and, remarkably, that no charge was stored in the center of the nanoring. It was also observed that topographic constructions in the nanostructures prevent transport and delocalization. The same experiments were performed with a negative bias (i.e., electron injection), but no charge delocalization was observed. These results could be correlated with the nature of 1, which is a good electron-donor, so it can easily be oxidized, but can be reduced only with difficulty.

Three novel phases in the Sm-Co-Ga system. Syntheses, crystal and electronic structures, and electrical and magnetic properties.

This paper presents the synthesis, identification, and characterization of three novel phases in the ternary system Sm-Co-Ga: SmCoGa5 (tP7, HoCoGa5 type, tetragonal P4/mmm, Z = 1, a = 4.2419(3) A, and c = 6.8559(5) A), Sm4Co3Ga16 (tP23, tetragonal P4/mmm, Z = 1, a = 6.0620(5) A, and c = 11.1495(9) A), and SmCoGa4 (oC24, YNiAl4 type, orthorhombic Cmcm, Z = 4, a = 4.1246(6) A, b = 15.608(2) A, and c = 6.4556(9) A). The structure of SmCoGa5 was obtained from a multiphase X-ray powder Rietveld refinement whereas the crystal structures of the other two phases were determined from single-crystal X-ray analysis. Electronic structures were calculated for all phases by first-principles DFT methods. The atomic arrangements and bonding are discussed on the basis of the partial anionic networks involving Co and Ga atoms, and a strong structural correlation is observed between SmCoGa5 and Sm4Co3Ga16. The latter, which displays paramagnetic behavior, has a resistivity of 4.2 microOmega.cm at 3 K and undergoes a superconducting transition at 2.8 K.

4-[Bis(1,5-dimethyl-1H-pyrazol-3-yl-methyl)amino]phenol monohydrate.

The crystal structure of the title compound, C18H23N5O.H2O, shows molecules containing a phenol group linked perpendicularly to a roughly planar fragment comprising two pyrazole rings. Molecules are stacked perpendicular to the [101] direction, with their phenol groups disposed alternately. The molecular packing in the crystal is stabilized by hydrogen bonding involving water molecules.

Diastereoselective addition of 2H-2-oxo-1,4,2-oxazaphosphinanes to aldehydes and imines.

[reaction: see text] Diastereoselective additions of 2-hydrogeno-2-oxo-1,4,2-oxazaphosphinanes to aldehydes and imines are described. alpha,alpha'-Diaminophosphinic and alpha-amino-alpha'-hydroxyphosphinic derivatives were obtained with de's ranging from 24 to 90%.

Sm5Ga3.

Single crystals of pentasamarium trigallium, Sm5Ga3, display tetragonal symmetry. The crystal structure was solved and refined in space group P4/ncc. The present work does not confirm the space group I4/mcm previously deduced from powder data measurements. One Sm atom is in a general position, and the other Sm atom and one of the Ga atoms are at sites with fourfold symmetry. The remaining Ga atom is at a site with twofold symmetry.

Two cubic polymorphs of AlGeLi.

Aluminium germanium lithium, AlGeLi, crystallizes in two cubic dimorphs. The structure of the F-43m form, already inferred from powder data, has been confirmed by both powder and single-crystal X-ray diffraction studies. The second dimorph, not previously identified, adopts a disordered centrosymmetric structure with space group Fm-3m.

Li15Al3Si6 (Li14.6Al3.4Si6), a compound displaying a heterographite-like anionic framework.

The title compound, lithium aluminium silicide (15/3/6), crystallizes in the hexagonal centrosymmetric space group P6(3)/m. The three-dimensional structure of this ternary compound may be depicted as two interpenetrating lattices, namely a graphite-like Li(3)Al(3)Si(6) layer and a distorted diamond-like lithium lattice. As is commonly found for LiAl alloys, the Li and Al atoms are found to share some crystallographic sites. The diamond-like lattice is built up of Li cations, and the graphite-like anionic layer is composed of Si, Al and Li atoms in which Si and Al are covalently bonded [Si-Al = 2.4672 (4) A].

Atomic structure of the (Al,Si)CuFe cubic approximant phase.

The structure of the alpha-(Al,Si)CuFe approximant phase is determined by a single-crystal X-ray diffraction study and compared to the ideal structure obtained by the perpendicular shear method of the parent icosahedral phase. It is shown that the local environments (typical atomic clusters) of the two phases are similar and expand significantly farther than the size of the unit cell of the approximant. The orbit Al(2) issuing from the theoretical icosahedral model corresponding to the inner dodecahedron of the Mackay-type cluster is not found in the approximant and is replaced by a partially occupied inner icosahedron with an unusually large Debye-Waller factor.