Efficient synthesis of diversely substituted pyrazolo[1,5-a]pyrimidine derivatives promoted by ultrasound irradiation in water and their antibacterial activities

A green synthetic route leading to the discovery of a series of diversely substituted pyrazolo[1,5-a]pyrimidines, having CO2Et group embedded at position-2 has been unraveled in this article. A series of formylated active proton compounds that were chosen to react with a carboxylate substituted-3-aminopyrazole under ultrasonic irradiation in the presence of a mild acid as a catalyst and aqueous ethanol medium afforded the desired products. The molecular structures of all these synthesized compounds were established by their spectral and analytical data. A model molecule 3d, subjected to single-crystal X-ray crystallography analysis further confirms their molecular structure. The crystal crystallized to a monoclinic cell with P21/c space group, a = 7.468 (5) Å, b = 27.908 (17) Å, c = 7.232 (4) Å, β = 104.291 (7)o, V =1460.7(15) Å3, Z = 4, μ(MoKα) = 0.096 mm-1, Dcalc = 1.352 Mg/m3 16667 measured reflection (5.63 ≤ 2Θ ≤ 57.57°), 3720 unique (Rint = 0.0965, Rsigma = 0.0945) which were used in all calculations. The final R1 was 0.0750 (I > 2σ(I)) and wR2 was 0.2226 (all data). These compounds were further explored for their antibacterial potential, and a few of them have exhibited encouraging results.

Structure, Infrared and Raman spectroscopic studies of new AII(SbV0.50CrIII0.50)(PO4)2 (A = Ba, Sr, Pb) yavapaiite phases

<p class="Mabstract">Three new A^II(Sb_0.5Cr_0.5)(PO₄)₂ (A^II = Ba, Sr, Pb) yavapaiite phases, abbreviated as [ASbCr], have been successfully synthesized by a conventional solid-state reaction in air atmosphere. Their crystal structures have been investigated by Rietveld analysis from the X-ray powder diffraction method. Results show that Ba(Sb_0.5Cr_0.5)(PO₄)₂ crystallizes in monoclinic <em>C</em>2<em>/m</em> space group (Z = 2) with cell parameters a = 8.140(1) Å; b = 5.175(1) Å; c = 7.802(1) Å and β = 94.387(1)°. Structures of A^II(Sb_0.5Cr_0.5)(PO₄)₂ (A^II= Sr, Pb) compounds are comparable, and both crystallize in a distorted yavapaiite structure with <em>C</em>2<em>/c</em> space group (Z = 4). Obtained monoclinic cell parameters are: a = 16.5038(2) Å; b = 5.1632(1) Å; c = 8.0410(1) Å; β = 115.85(1) for [SrSbCr] and a = 16.684(2) Å; b = 5.156(1) Å c = 8.115(1) Å; β = 115.35(1)° for [PbSbCr]. Infrared and Raman spectroscopic study was undertaken to provide information about vibrations bonds within the studied yavapaiite materials.</p>

Crystallization of metastable monoclinic carnallite, KCl·MgCl2·6H2O: missing structural link in the carnallite family

During evaporation of natural and synthetic K–Mg–Cl brines, the formation of almost square plate-like crystals of potassium carnallite (potassium chloride magnesium dichloride hexahydrate) was observed. A single-crystal structure analysis revealed a monoclinic cell [a = 9.251 (2), b = 9.516 (2), c = 13.217 (4) Å, β = 90.06 (2)° and space group C2/c]. The structure is isomorphous with other carnallite-type compounds, such as NH4Cl·MgCl2·6H2O. Until now, natural and synthetic carnallite, KCl·MgCl2·6H2O, was only known in its orthorhombic form [a = 16.0780 (3), b = 22.3850 (5), c = 9.5422 (2) Å and space group Pnna].

Monoclinic polymorph of chlorido(dimethyl sulfoxide-κO)triphenyltin(IV)

The crystal structure of the title tin complex, [Sn(C6H5)3Cl(C2H6OS)], (I), has been reported with one molecule in the asymmetric unit in an orthorhombic cell [Kumar et al. (2009). Acta Cryst. E65, m1602–m1603]. While using SnPh3Cl as a starting material for a reaction for which the products were recrystallized over a very long time (six months) from dimethyl sulfoxide (DMSO), a new polymorph was obtained for (I), with two independent molecules in the asymmetric unit of a monoclinic cell. The coordination geometry of the Sn centres remains unchanged, with the Cl− ion and the DMSO molecule in the apical positions and the phenyl C atoms in the equatorial positions of a trigonal bipyramid. The main difference between the polymorphs is the relative orientation of the phenyl rings in the equatorial plane, reflecting a degree of free rotation of these groups about their Sn—C bonds. In the crystal, molecules are linked into [010] chains mediated by weak C—H...O interactions.

Powder diffraction data for ferrous gluconate

Synchrotron powder diffraction data have been obtained and indexed for ferrous gluconate, a common supplement used for the treatment and prevention of iron-deficiency anemia. Ferrous gluconate (Fe(C6H11O7)2 · x H2O, Z = 4) crystallizes in a monoclinic cell (space group I2, #5) with lattice parameters a = 19.953 16(9) Å, b = 5.513 92(3) Å, c = 18.470 58(9) Å, and β = 111.3826(3)°. The pattern shows no evidence of impurity reflections.

Old structures revisited: Better insights from new data

The need for improving the description of structural features with better quality data, at low temperature and with modern 2D detectors of certain materials, sometimes leads to surprisingly new insights into a previously reported structure. When attempting to grow single crystals of maleamic acid, good crystals of ammonium maleate, NH4(Mal), were obtained. Although the structure of this material has been reported at room temperature, in space group Pbcm with V=613.2(5) Å3[1], synchrotron data were collected at low temperature to examine the behavior of the ammonium moiety. The data collected lead to a structure better described in Pbca, a=8.9687(12), b=8.1604(8), c=16.348(2) Å, V=1196.5(2) Å3, Z=8. The refinement converged to R=0.0438, wR2=0.1156, S=1.02. An examination of the new data indicates that reflections with h odd are systematically weak but, nevertheless, present. The Ca derivative of valproic acid (a common anticonvulsant) was reported as monoclinic, C2/c, with a=16.250(8), b=18.471(17), c=7.729(7) Å, β=109.71(5)0, V=2183.97 Å3, Z=4, and R=10.94% [2]. However, data collection at room temperature and under a stream of nitrogen on several newly prepared crystals always lead to a triclinic, P-1 cell, with approximately half the volume of the reported cell. Attempts to index the dataset using the known monoclinic cell resulted in high uncertainties for the unit cell parameters and high Rint values since reflection spots showed splitting and diffuse scattering. The new cell had dimensions a=7.6995(4) Å, b=11.7444(6) Å, c=11.7708(6) Å, α=91.089(3)0, β=101.643(3)0, γ=102.041(3)0, V=1017.47(99) Å3, Z=2. Although the initial refinement was discouraging (R=0.1172, wR2=0.360, S=1.12) the analysis with PLATON indicated the presence of twining and, after considering the twin law, the refinement improved significantly (R=0.059, wR2=0.1472, S=0.99). Several examples where a new data collection resulted in interesting results will be presented.

Transmission Electron Microscopy Study of CaFe5O7 : Evidence of a Monoclinic Superstructure at Room Temperature

An efficient synthesis route is proposed to obtain single powder CaFe5O7ceramic. This complex structure can be described as an intergrowth between one CaFe2O4unit and n= 3 slices of FeO Wustite-type structures. A fine structural study has been carried out at room temperature by transmission electron microscopy (TEM) observations (ED and HREM). The analysis of these data has revealed a supercell with a monoclinic symmetry associated to some twinning phenomena. From thehklconditions deduced to electron diffraction study, the centrosymmetric P21/m setting can be proposed. This monoclinic cell exhibit close relationships with the previous one reported as orthorhombic (ao=3.05 Å, bo= 10.05 Å and co= 18 Å) according to the following metric am=2co, bm=co, cm=bo/2sinβ and β=106.74°.

X-ray powder diffraction data for the Al3Ho2Si2 ternary compound

Crystal and X-ray powder diffraction data are presented for the Al3Ho2Si2 ternary compound. The powder pattern was indexed and refined on a monoclinic cell with the Al3Y2Si2 structure type with space group C12/m1, a = 10.1096(2) Å, b = 4.020(6) Å, c = 6.5734(6) Å, β = 100.848(2)°, V = 262.37 Å3, Z = 2ρx = 5.910 g cm−3, F30 = 142.8(0.006, 35), and RIR = 0.91.

Bis(4-picoline-κN)gold(I) dibromidoaurate(I) and bis(4-picoline-κN)gold(I) dichloridoaurate(I): space-group ambiguity?

Bis(4-picoline-κN)gold(I) dibromidoaurate(I), [Au(C6H7N)2][AuBr2], (I), crystallizes in the monoclinic space groupP21/n, with two half cations and one general anion in the asymmetric unit. The cations, located on centres of inversion, assemble to form chains parallel to theaaxis, but there are no significant contacts between the cations. Cohesion is provided by flanking anions, which are connected to the cations by short Au...Au contacts and C—H...Br hydrogen bonds, and to each other by Br...Br contacts. The corresponding chloride derivative, [Au(C6H7N)2][AuCl2], (II), is isotypic. A previous structure determination of (II), reported in the space groupP\overline{1} with very similar axis lengths to those of (I) [Linet al.(2008).Inorg. Chem.47, 2543–2551], might be identical to the structure presented here, except that its γ angle of 88.79 (7)° seems to rule out a monoclinic cell. No phase transformation of (II) could be detected on the basis of data sets recorded at 100, 200 and 295 K.

Structural and magnetic investigation of Ca2MnReO6 doped with Ce

We have studied the properties of Ce doping in Ca-site of Ca2MnReO6 double perovskite up to 10%. These compounds have presented a monoclinic cell with P2(1)/n space group. A small increase of lattice parameters in doped sample were observed through Rietveld refinement of X-ray diffraction pattern. The spectra at the Mn K-edge and Re L3-edge showed a mixed valence for Mn and Re in both samples. We do not observed any variation on Mn K-edge valence in XANES measurements under pressure. However a change was observed for Re L3-edge as a function of applied pressure. The Ce-doped sample showed a magnetic geometric frustration and a small decrease of the temperature frustration as compared with Ca2MnReO6 sample. The decrease of temperature frustration can be related to the MnO6 and ReO6 octahedral distortion.