Synthesis, crystal structure, and vibrational spectra of the complex maleic acid•2H2O•18-crown-6

1990 ◽  
Vol 68 (12) ◽  
pp. 2183-2189 ◽  
Author(s):  
Pierre Audet ◽  
Rodrigue Savoie ◽  
Michel Simard

A stoichiometric complex of formula maleic acid•2H2O•18-crown-6 has been obtained from maleic acid and the macrocyclic polyether 18-crown-6. Crystals of this complex have been shown by X-ray diffraction crystallography to belong to the Cc space group of the monoclinic system. The acid molecules in the adduct are linked to each other through a water molecule, giving infinite [-acid-H2O-]n chains. They are also linked to the crown ether via water molecules. The infrared and Raman spectra of the complex are presented and compared to those of crystalline maleic acid. Keywords: maleic acid/18-crown-6, structure, X-ray, spectra.

1979 ◽  
Vol 32 (2) ◽  
pp. 301 ◽  
Author(s):  
V Diakiw ◽  
TW Hambley ◽  
DL Kepert ◽  
CL Raston ◽  
AH White

The crystal structure of the title compound, Ca(C6H2N307)2,5H2O, has been determined by single-crystal X-ray diffraction at 295(1) K and refined by least squares to a residual of 0.049 for 1513 'observed' reflections. Crystals are orthorhombic, Pmab, a 24.169(6), b l0.292(7), c 8.554(2) �, Z 4. The stereochemistry about the calcium has not been observed previously for the system [M(bidentate)2- (unidentate)4]; in the present structure, the calcium is coordinated by a pair of bidentate picrate ligands and the four water molecules in an array in which three of the water molecules occupy a triangular face of a square antiprism, the overall array having m symmetry. The remaining water molecule occupies a lattice site with no close interaction with the other species.


2014 ◽  
Vol 69 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Olaf Reckeweg ◽  
Armin Schulz ◽  
Björn Blaschkowski ◽  
Thomas Schleid ◽  
Francis J. DiSalvo

The crystal structure of Li[SCN] · 2 H2O has been determined by single-crystal X-ray diffraction on commercially available material. Crystals of this compound are colorless, transparent and hygroscopic. Li[SCN] · 2H2O adopts the orthorhombic space group Pnma with the cell parameters a = 572.1(3), b = 809.3(4) and c = 966.9(4) pm and Z = 4. Li[SCN] was obtained by dehydration of the afore-mentioned dihydrate and also crystallizes orthorhombically in Pnma with the lattice parameters a = 1215.1(3), b = 373.6(1) and c = 529:9(2) pm (Z = 4). Both compounds contain Li+ cations in sixfold coordination. Four water molecules and two nitrogen-attached thiocyanate anions [SCN]- arrange as trans-octahedra [Li(OH2)4(NCS)2]- in the case of Li[SCN] · 2 H2O. Anhydrous Li[SCN] displays fac-octahedra [Li(NCS)3(SCN)3]5- with six thiocyanate anions grafting via both nitrogen and sulfur atoms, three each. Infrared and Raman spectra of both compounds were recorded and a DSC=TG measurement was performed on Li[SCN] · 2 H2O.


2010 ◽  
Vol 6 (1) ◽  
pp. 891-896
Author(s):  
Manel Halouani ◽  
M. Dammak ◽  
N. Audebrand ◽  
L. Ktari

One nickel 1,4-cyclohexanedicarboxylate coordination polymers, Ni2 [(O10C6H4)(COO)2].2H2O  (I), was hydrothermally synthesized from an aqueous solution of Ni (NO3)2.6H2O, (1,4-CDC) (1,4-CDC = 1,4-cyclohexanedicarboxylic acid) and tetramethylammonium nitrate. Compound (I) crystallizes in the monoclinic system with the C2/m space group. The unit cell parameters are a = 20.1160 (16) Å, b = 9.9387 (10) Å, c = 6.3672 (6) Å, β = 97.007 (3) (°), V= 1263.5 (2) (Å3) and Dx= 1.751g/cm3. The refinement converged into R= 0.036 and RW = 0.092. The structure, determined by single crystal X-ray diffraction, consists of two nickel atoms Ni (1) and Ni (2). Lots of ways of which is surrounded by six oxygen atoms, a carboxyl group and two water molecules.


2021 ◽  
Vol 91 (11) ◽  
pp. 2176-2186
Author(s):  
G. S. Tsebrikova ◽  
Yu. I. Rogacheva ◽  
I. S. Ivanova ◽  
A. B. Ilyukhin ◽  
V. P. Soloviev ◽  
...  

Abstract 2-Hydroxy-5-methoxyphenylphosphonic acid (H3L1) and the complex [Cu(H2L1)2(H2O)2] were synthesized and characterized by IR spectroscopy, thermogravimetry, and X-ray diffraction analysis. The polyhedron of the copper atom is an axially elongated square bipyramid with oxygen atoms of phenolic and of monodeprotonated phosphonic groups at the base and oxygen atoms of water molecules at the vertices. The protonation constants of the H3L1 acid and the stability constants of its Cu2+ complexes in water were determined by potentiometric titration. The protonation constants of the acid in water are significantly influenced by the intramolecular hydrogen bond and the methoxy group. The H3L1 acid forms complexes CuL‒ and CuL24‒ with Cu2+ in water.


2012 ◽  
Vol 68 (8) ◽  
pp. o2357-o2357 ◽  
Author(s):  
María-Guadalupe Hernández Linares ◽  
Sylvain Bernès ◽  
Marcos Flores-Alamo ◽  
Gabriel Guerrero-Luna ◽  
Anselmo A. Martínez-Gallegos

Diosgenin [or (22R,25R)-spirost-5-en-3β-ol] is the starting material of the Marker degradation, a cheap semi-synthesis of progesterone, which has been designated as an International Historic Chemical Landmark. Thus far, a single X-ray structure for diosgenin is known, namely its dimethyl sulfoxide solvate [Zhanget al.(2005).Acta Cryst.E61, o2324–o2325]. We have now determined the structure of the hemihydrate, C27H42O3·0.5H2O. The asymmetric unit contains two diosgenin molecules, with quite similar conformations, and one water molecule. Hydroxy groups in steroids and water molecules form O—H...O hydrogen-bondedR54(10) ring motifs. Fused edge-sharingR(10) rings form a backbone oriented along [100], which aggregates the diosgenin molecules in the crystal structure.


1999 ◽  
Vol 32 (5) ◽  
pp. 968-976 ◽  
Author(s):  
S. Jemai ◽  
A. Ben Haj Amara ◽  
J. Ben Brahim ◽  
A. Plançon

Two hydrated kaolinites, characterized by 10 and 8.4 Å basal distances, were synthesized by treating the kaolinite KGa-1 with dimethyl sulfoxide (DMSO) and ammonium fluoride (NH4F). The X-ray diffraction study was based on a comparison between the experimental and calculated profiles. This study was conducted in two steps: firstly, the study of the 00lreflections enabled the determination of the stacking mode alongc*, the number of water molecules and their positions along the normal to the plane of the sheet structure; secondly, the study of thehkbands, withhand/ork≠ 0, enabled the determination of the stacking mode and the positions of the water molecules in the (a,b) plane. The 10 Å hydrated kaolinite is characterized by two water molecules per Al2Si2O5(OH)4unit, situated at 3 and 3.4 Å from the hydroxyl surface, over the octahedral sites. Two adjacent layers are translated with respect to each other, withT11= −0.38a− 0.37b+ 10n. The 8.4 Å hydrated kaolinite is characterized by one water molecule per Al2Si2O5(OH)4unit, situated at 2.4 Å from the hydroxyl surface and inserted between the vacant octahedral site and the ditrigonal cavity of the tetrahedral sheet. The corresponding interlayer shift isT11= −0.355a+ 0.35b+ 8.4n.


2011 ◽  
Vol 6 (11) ◽  
pp. 1934578X1100601
Author(s):  
Yang Li ◽  
Jun-Hui Zhou ◽  
Gui-Jun Han ◽  
Min-Juan Wang ◽  
Wen-Ji Sun ◽  
...  

The crystal structure of natural diterpenoid alkaloid ranaconitine isolated from Aconitum sinomontanum Nakai has been determined by single crystal X-ray diffraction analysis. The crystal presents a monoclinic system, space group C2 with Z = 4, unit cell dimensions a = 30.972(19) Å, b = 7.688(5) Å, and c = 19.632(12) Å. Moreover, the intermolecular O–H···O hydrogen bonds and weak π-π interactions play a critical role in expanding the dimensionality.


2001 ◽  
Vol 56 (10) ◽  
pp. 1025-1034 ◽  
Author(s):  
Markus Ströbele ◽  
H.-Jtirgen Meyer

The title compounds were prepared through reactions of Li2Nb6Cl16 with the corresponding crown ethers in acetone. All three compounds were obtained as dark brown crystals. Their structures were solved with the means of single-crystal X-ray diffraction.[Li(12-crown-4)2][Li(12-crown-4)(OH2)]2[Nb6Cl18]: space group P21/n, Z =2, a = 1320.4(1), b = 1879.1(1), c = 1321.7(1) pm, ß = 92.515(6)°, R1 = 0.0297 (I>2σ(I)). The crystal structure contains Li+ sandwiched by two 12-crown-4-ethers plus Li+ coordinated by one 12-crown-4- ether and one water molecule.[Li(15-crown-5)2(OH2)]3[Nb6Cl18]: space group R3̅, Z = 3, a = b = 2081.7(1), c = 1991.7(1) pm, R1 = 0.0395 (I > 2σ(I)). In the crystal structure Li+ and one water molecule are sandwiched by two 15-crown-5-ethers.[(18-crown-6)2(O2H5)]3[Nb6Cl18]: space group P1̅, Z = 1 ,a = 1405.1(1), b = 1461.1(2), c = 1492.2(2) pm; α = 98.80(1)°, ß = 98.15(1)°, γ = 97.41(1)°, R1 = 0.0538 (I > 2σ(I)). H5O2+ was found in the structure refinement sandwiched between two 18-crown-6-ethers.All compounds reported contain [Nb6Cl18] clusters with Nb-Nb distances between 299 and 301 pm. The paramagnetic behaviour expected for [Nb6Cl18]3- in all three compounds was confirmed by magnetic measurements.


1980 ◽  
Vol 33 (1) ◽  
pp. 69 ◽  
Author(s):  
GJ Honan ◽  
DL Kepert ◽  
SF Lincoln ◽  
JM Patrick ◽  
AH White

The crystal structure of the title compound, [UO2{OCHN(CH2)5}4(H2O)] (ClO4)2, has been determined by single-crystal X-ray diffraction at 295 K and refined by least squares to a residual of 0.051 for 3113 'observed' reflections. Crystals are monoclinic, C2/c, a 16.945(2), b 12.711(2), c 17.304(2)Ǻ, β 107.76(1)°, Z 4. The uranyl moiety [U=O, 1.76(2)Ǻ] is five-coordinated in the equatorial plane by the water molecule [U-O, 2.436(8)Ǻ] and four organic ligands [U-O, 2.379(8), 2.396(13)Ǻ]. The angles O-U-O in the equatorial plane range from 70.3(3) to 73.6(3)°; O=U-0 range between 86.7 and 95.3°. The angle O=U=O is 177.8(3)°. The stereochemistry of seven-coordinate uranyl compounds is examined by using repulsion theory.


1978 ◽  
Vol 33 (12) ◽  
pp. 1386-1392 ◽  
Author(s):  
Jochen Ellermann ◽  
Helmut A. Lindner ◽  
Horst Schössner ◽  
Gerhard Thiele ◽  
Gerd Zoubek

Abstract The organocyclotriarsane, CH3C(CH2As)3 (1), reacts with chromium hexacarbonyl on ultraviolet irradiation to give the complex CH3C(CH2As)3Cr(CO)5 (2), in which the cyclo-triarsane is behaving as a monodentate ligand. The crystal structure of 2 has been determinated by X-ray diffraction. The monoclinic unit cell (space group P21/n) contains 4 isolated molecules in a hexagonal closest packing. The mass spectrum of 2 shows the parent peak and clear fragmentation patterns. The infrared and Raman spectra are reported for 1 and 2 in the 3000-30 cm-1 region. Most of the fundamental vibrations are assigned.


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