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Showing papers in "Journal of Chemical Crystallography in 1991"


Journal ArticleDOI
TL;DR: In this article, the Na2CoP2O7 may be prepared in two allotropie forms: I, rose, M====== r =278.12 cm−1, F(000)=540,T=298 K,R=5.4% for 2911 observed reflections; and II, blue, M¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ r =278.55 cm− 1, F (000)=1080, T=298 k, R=9.9% for 1450 observed reflections.
Abstract: Na2CoP2O7 may be prepared in two allotropie forms:I, rose,M r =278.85, triclinic, P1,a=9.735(2),b=10.940(3),c=12.289(4) A,α=148.78,β=121.76(1), γ=68.38(2)°,V=566.8(2) A3,Z=4,D meas=3.28(5) g cm−3,D calc=3.267 g cm−3, λ(MoKα)=0.71069 A,μ=37.12 cm−1, F(000)=540,T=298 K,R=5.4% for 2911 observed reflections; andII, blue,M r =278.85, orthorhombic, P21cn,a=7.713(2) A,b=10.271(4),c=15.378(6)°,V=1218.2(8) A3,Z=8,D meas=3.06(5) g cm−3,D calc=3.040 g cm−1, λ(MoK α) A,μ=34.55 cm−1, F(000)=1080,T=298 K,R=9.9% for 1450 observed reflections. Cobalt displays octahedral coordination to six oxygen atoms in the rose form whereas the metal coordination is tetrahedral in the blue form.

67 citations


Journal ArticleDOI
TL;DR: The reaction between freshly precipitated silver oxide Ag2O and an aqueous solution of tetrabenzenecarboxylic acid H4L leads to the anhydrous Ag2H2L complex as mentioned in this paper.
Abstract: The reaction between freshly precipitated silver oxide Ag2O and an aqueous solution of tetrabenzenecarboxylic acid H4L leads to the anhydrous Ag2H2L complex. It crystallizes in the space groupP21/c, witha=6.457(1),b=8.180(1),c=9.982(1) A, β=97.83(1)°,V=522.3(1) A3,Z=2,d=2.976 g cm−3. This structure is a three dimensional polymeric network polymer without any silver...silver interaction. The silver environment is a bipyramid trigonal polyhedron with three short bond distances in the equatorial plane (Ag−O=2.255(2), 2.295(2), and 2.499(2) A) and two longer bond distances in axial positions (Ag−O=2.558(2) and 2.617(2) A). Thus, the silver polyhedron involves five different ligands. It is noteworthy that the (H2L2)2− ligand is located around an inversion centre.

43 citations


Journal ArticleDOI
TL;DR: The La2(C2O4)3·10H2O structure as mentioned in this paper is composed of two-dimensional networks of edge-sharing 1∶5∶3 coordination polyhedra matching the (020) set of planes.
Abstract: La2(C2O4)3·10H2O crystallizes in space groupP21/c (No. 14) witha=11.382(6),b=9.624(5),c=10.502(8) A,β=114.52(4)°, andZ=2. The structure (R=0.029 for 3190 MoKα data) is composed of two-dimensional networks of edge-sharing 1∶5∶3 coordination polyhedra matching the (020) set of planes, each La(III) atom being surrounded by threeη4 chelating oxalate groups and three aqua ligands with La-O distances in the range 2.518(4)–2.622(4) A. The remaining water molecules are disordered over seven principal sites in the intervening space.

32 citations


Journal ArticleDOI
TL;DR: In this article, the authors describe a three-dimensional network of disordered disordered ethylenediammonium cations, water molecules and polynuclear anions in which slightly distored [BiI6]3− octahedra sharingcis edges are interconnected into chains.
Abstract: The ethylenediammonium bis tetraiodobismuthate(III) tetrahydrate salt is monoclinic with the following unit cell dimensions:a=7.476(3)A,b=13.194(3)A,c=13.916(9)A, β=95.22(6)°, space groupP21lc withZ=2. The structure consists of disordered ethylenediammonium cations, water molecules and polynuclear anions in which slightly distored [BiI6]3− octahedra sharingcis edges are interconnected into chains. The [BiI4]− anions are connected through O(W2)−H...I hydrogen bonds, so that infinite two dimensional chains parallel to thea axis with anionic period [BiI4(H2O)]− are formed in the structure. These chains are themselves interconnected by means of the O−H...I and N...O(I) bonds originating respectively from the water molecules and the ethylenediammonium entities, forming a three-dimensional network.

29 citations


Journal ArticleDOI
TL;DR: The crystal structure of iron(II) pentacyanonitrosylferrate trihydrate has been determined from three dimensional, single-crystal X-ray diffraction data as discussed by the authors.
Abstract: The crystal structure of iron(II) pentacyanonitrosylferrate trihydrate has been determined from three dimensional, single-crystal X-ray diffraction data. Fe[Fe(CN)5NO]·3H2O crystallizes in the monoclinic space group P21/n with lattice constants,a=7.205(1),b=14.641(2),c=10.680(1) A,β=91.14(1)° andZ=4,Dm=1.89(1) g cm−3 andDx=1.92 g cm−3. Final full-matrix least-squares refinement of 1691 unique reflections yieldedR=0.024 andRw=0.028. Both iron atomic centers have distorted octahedral symmetries. The cation iron center is coordinated by five cyanide ligands and one water molecule, while the second iron center is coordinated by five cyanide ligands and one nitrosyl group. Cyanide bridging links the metal centers. Two uncoordinated water molecules, O(2) and O(3), are hydrogen bonded to the coordinated water molecule, O(1), and occupy channels in the crystal lattice. Important mean bond distances for iron nitroprusside are: Fe(cation)-N=2.159(17), Fe-C=1.936(4) and C=N=1.144(6) A. Other notable bond lengths include: Fe-O(1)=2.152(2), Fe-NO=1.669(2) and N≡O=1.131(3) A. The distances between the coordinated water molecule and two uncoordinated water molecules are 2.855(3) and 2.740(3) A.

29 citations


Journal ArticleDOI
TL;DR: The title compound was synthesized by the reaction of [H3O+·18crown-6][Cl-H-Cl−]·38 C6H5Me with two equivalents of H2O Colorless crystals, which slowly deposited from the corresponding liquid clathrate, belong to the monoclinic space group P21/n witha=10648(6),b=9571(2),c=20801(6) A,β=9867(5)°, andDc=124 g cm−3 forZ=4
Abstract: The title compound was synthesized by the reaction of [H3O+·18-crown-6][Cl-H-Cl−]·38 C6H5Me with two equivalents of H2O Colorless crystals, which slowly deposited from the corresponding liquid clathrate, belong to the monoclinic space group P21/n witha=10648(6),b=9571(2),c=20801(6) A,β=9867(5)°, andD c=124 g cm−3 forZ=4 Refinement based on 1609 observed reflections led to a finalR value of 0072 In the crystal structure the [H3O+·18-crown-6]+ cations are packed in layers separated by puckered sheets of [(H5O 2 + )(Cl−)2]−

28 citations


Journal ArticleDOI
TL;DR: The crystal and molecular structures of the 1∶1 complexes of sulfadimidine·2-aminobenzoic acid (I) and 2-amino acid (II) are described in this paper.
Abstract: The crystal and molecular structures of the 1∶1 complexes sulfadimidine·2-aminobenzoic acid (I) and sulfadimidine·4-aminobenzoic acid (II) are described and compared with known structures containing sulfadimidine. In each complex, molecular association is maintained by one N-H⋯O hydrogen bond, and one O-H⋯N hydrogen bond involving the imino N and one pyrimidinyl N atom of sulfadimidine and the two carboxyl O atoms of the aromatic acid. The conformation of the sulfadimidine molecule inII is unusual for anN1-substituted arylsulfonamide. Molecular dimensions for the complexed aminobenzoic acids are virtually the same as those reported for the free acids. Partial correlation between carboxylic acid strengths and the hydrogen bonded N⋯O distances is observed in sulfadimidine complexes of this type.

27 citations


Journal ArticleDOI
TL;DR: Piroxicam (4-hydroxy-2-methyl-N-2piridyl-2H1,2-benzothiazine-3-carboxamide1,1-dioxide) belongs to the class of acidic, nonsteroidal antiinflammatory drugs (Wiseman et al., 1976).
Abstract: Piroxicam (4-hydroxy-2-methyl-N-2-piridyl-2H1,2-benzothiazine-3-carboxamide1,1-dioxide), belongs to the class of acidic, nonsteroidal antiinflammatory (NSAI) drugs (Wiseman et al., 1976). Piroxicam is an effective analgesic agent in rheumatoid arthritis, ankylosing spondylitis, and acute pain in muskuloskeletal disorder and episiotomy. It can diminish or inhibit the development of all symptoms of inflammation no matter what its reason (Brogden et al., 1981). Piroxicam crystallizes in two modifications o~ and/3 (Fig. 1), in space groups Pca21 with Z = 4 and P21/c with Z = 4 (Reck et al., 1988; Kojir-Prodi6 and Ruzir-Toros, 1982), respectively. The conformation of the molecule in both structures is approximately planar and rigid, owing to the strong intramolecular hydrogen bonding O ( 1 7 ) H . . . O ( 1 5 ) of lengths 2.526(2)A (cr and 2.561(5),~ (/3). The crystals with the c~ modification exhibit more or less disorder (Reck et al., 1988) depending on crystallization conditions. The c~ structure is rigid owing to the formation of the infinite chains of the weak bifurcated intermolecular hydrogen bonds O ( 1 7 ) H . . . O ( 1 2 ) of the length 3.007 A,. The free N(16)--H groups have the intermolecular distances close to the van der Waals' (Reck et al., 1988). The/3 structure contains the cyclic dimers with the intermolecular hydrogen bonds N(16)--H 9 9 9 O(11) of

22 citations


Journal ArticleDOI
TL;DR: In this paper, the crystal structure and some physico-chemical properties of MnCl2·Pro·H2O (Pro=L-proline) were studied and the IR spectrum was recorded.
Abstract: The crystal structure and some physico-chemical properties of MnCl2·Pro·H2O (Pro=L-proline) were studied. This compound is stable up to approximately 313 K. Upon heating the complex loses a molecule of water and is transformed into the oxide in two steps. The IR spectrum was recorded. The compound crystallizes in the orthorhombic space groupP212121 witha=7.112(2) A,b=10.196(2) A,c=13.249(3) A andZ=4. The manganese atoms in the polymeric chain are bridged by two chlorine atoms and oxygen atoms from the carboxylate group of L-proline. The Mn−Cl bond distances range from 2.535(1) A to 2.581(1) A, the Mn−O bond distances range from 2.135(2) A to 2.153(2) A and Mn−Mn bond distances are 3.556(1) A. One molecule of water is hydrogen-bonded with a nitrogen atom of the L-proline ring.

22 citations


Journal ArticleDOI
TL;DR: The Ru atom in the title compound, [Ru(dppe)(2-pyS)2] exists in a distorted octahedral geometry defined by a dppe ligand and two 2-py S anions which function as bidentate ligands via their N- and S-atoms as mentioned in this paper.
Abstract: The Ru atom in the title compound, [Ru(dppe)(2-pyS)2] exists in a distorted octahedral geometry defined by a dppe ligand and two 2-pyS anions which function as bidentate ligands via their N- and S-atoms. Important interatomic parameters are Ru-P2.240(3), 2.256(3); Ru-N 2.131(8), 2.136(8); Ru-S 2.413(3), 2.428(3) A; P-Ru-P 84.1(1), S-Ru-S 155.0(1) and N-Ru-N 87.5(3)°. Crystals are monoclinic, space groupP21/c, with unit cell dimensionsa=10.342(1),b=31.145(6),c=11.107(2) A,β=113.80(1)° andZ=4. The structure was refined to finalR=0.064 for 3057 reflections withI≥2.5σ(I).

18 citations


Journal ArticleDOI
TL;DR: In this paper, a new polymeric betaine complex of manganese(II), of stoichiometry [Mn(C5H5NCH2COO)2 (H2O)2]C12, has been prepared and characterized by infrared spectroscopy and X-ray crystallography.
Abstract: A new polymeric betaine complex of manganese(II), of stoichiometry [Mn(C5H5NCH2COO)2 (H2O)2]C12, has been prepared and characterized by infrared spectroscopy and X-ray crystallography. The complex exhibits strong carboxylate absorptions at 1624, 1396, 1384, and 715 cm−1. The crystal structure has been refined toR F =0.057 for 2342 observed (∥F 0∥>6σ∥F 0∥) MoKα data. The complex consists of a packing ofsyn-anti carboxylate-bridged, one-dimensional polymeric chains running parallel to thea axis. Each Mn(II) atom is located at an inversion center, with aqua ligands occupying the trans positions in a slightly distorted octahedron. The chloride ions and aqua ligands are alternately linked by O-H⋯Cl hydrogen bonds into a (Cl−·H2O)∞ zigzag chain also running parallel to thea axis.

Journal ArticleDOI
TL;DR: Two cadmium(II) complexes of betaine (BET) have been prepared and characterized by X-ray crystallography as discussed by the authors, and they have been shown to be a one-dimensional polymer in which each Cadmium atom is coordinated by two pairs of bridging chlorine atoms and two oxygen atoms from different bridging carboxylate groups.
Abstract: Two cadmium(II) complexes of betaine (BET) have been prepared and characterized by X-ray crystallography. [Cd(BET) (μ−Cl)2]∞ (1), is a one-dimensional polymer in which each cadmium atom is coordinated by two pairs of bridging chlorine atoms [Cd-Cl=2.631(2), 2.614(2) A] and two oxygen atoms from different bridging carboxylate groups [Cd-O=2.291(6), 2.329(6) A] in the form of a compressed octahedron. [Cd(BET)(H2O)Cl(μ−Cl)]2 (2) is a dimer with each cadmium atom in a distorted octahedral coordination environment, being surrounded by a chelating bidentate carboxylate group [2.480(2), 2.332(3) A], one aqua ligand [2.364(3) A], two bridging chlorine atoms [2.659(1), 2.557(1) A], and one terminal chlorine atom [2.480(1) A].

Journal ArticleDOI
TL;DR: In this article, the cross-polarization magic angle carbon-13 nmr spectra of a series of bis(xanthato) complexes of mercury(II) are reported; [Hg(S2COR)2]
Abstract: The cross-polarization magic angle carbon-13 nmr spectra of a series of bis(xanthato) complexes of mercury(II) are reported; [Hg(S2COR)2] n R=Me, Et, n Pr and i Pr. The spectra correlate well with the known crystal structures of theR=Me, Et, and i Pr compounds and with that of theR= n Pr derivative for which a single-crystal X-ray diffraction study is also reported. The X-ray analysis of [Hg(S2CO n Pr)2] n shows that this compound adopts a two-dimensional structure comprised of connected 16-membered rings which arise as a result of bridgingn-propylxanthate ligands. The mercury atom lies on a crystallographic twofold axis of symmetry and exists in a distorted tetrahedral geometry with two unique Hg-S bond distances of 2.418(3) and 2.835(4) A. Unit-cell dimensions for [Hg(S2CO n Pr)2] n are:a=7.371(3),b=8.534(4),c=11.618(4) A andZ=2 for the orthorhombic space groupP21212. The structure was refined by a full-matrix least-squares procedure to finalR=0.047 andR w =0.044 for 899 reflections withI≥2.5σ(I). While the solid state nmr spectra provide information on molecular (and crystallographic) symmetry they do not provide sufficient detail to enable structure determination for the [Hg(S2COR)2] compounds.

Journal ArticleDOI
TL;DR: In this paper, the synthesis and structures of 1,3-dithiole and tetrathiafulvalene derivatives of benzoquinone have been investigated, using cyclic voltammetry measurements.
Abstract: The syntheses and structures of 1,3-dithiole and tetrathiafulvalene derivatives of benzoquinone have been investigated. This work extends earlier investigations of naphthoquinone analogues. The X-ray structures, NMR, IR, UV, mass spectra, and E0 1/2 values from cyclic voltammetry measurements are reported.Ab initio STO-6-31G calculations are used to correlate the cyclic voltammetry and UV data for selected compounds.

Journal ArticleDOI
TL;DR: A new stemona alkaloid, tuberostemonone (C22H31NO6), has been isolated from the roots ofstemona tuberosa Lour, and its molecular structure determined by MS, IR, NMR spectra and X-ray crystallography (R=0.046 for 1746 observed Mo-Kα data) as mentioned in this paper.
Abstract: A newstemona alkaloid, tuberostemonone (C22H31NO6), has been isolated from the roots ofstemona tuberosa Lour, and its molecular structure determined by MS, IR, NMR spectra and X-ray crystallography (R=0.046 for 1746 observed Mo-Kα data). Besides retaining the characteristicstemona skeleton, which is composed of anα-methyl-γ-lactone and anN-methylene azepine ring linked at the γ-position of this lactone, the tuberostemonone molecule possesses a nine-membered azacycle which is hitherto not found in other knownstemona alkaloids.

Journal ArticleDOI
TL;DR: In this article, the structures of two molecular inclusion complexes have been elucidated by X-ray crystallography from single crystal diffraction data, and each structure was solved by direct methods and refined to final R values of 0.051.
Abstract: The structures of two molecular inclusion complexes have been elucidated by X-ray crystallography from single crystal diffraction data. Compound (1): (−)-(R,R)-trans-4,5-bis(hydroxy-diphenylmethyl)-2,2-dimethyl-1,3-dioxacyclopentane·(−)-R-6-methylbicyclo[4.4.0] dec-1-ene-3-one, C31H30O4·C11H16O, is orthorhombicP212121,a=9.606(2),b=9.708(1),c=36.628(3) A,V=3415.8(8) A3. Compound (2): (−)-(R,R)-trans-4,5-bis(hydroxy-diphenylmethyl)-2,2-dimethyl-1,3-dioxacyclopentane. (−)-R-6-methylbicyclo[4.4.0]dec-1-ene-3,7-dione, C31H30O4·C11H14O2, is orthorhombicP212121,a=9.671(1),b=9.691(2),c=36.526(4) A,V=3423.3(9) A3. Each structure was solved by direct methods and refined to final R values of 0.051. In each structure there is host-host and host-guest hydrogen bonding: despite the existence of a second H-bond acceptor in the guest of (2), the structures of (1) and (2) are isomorphous; the thermal properties of (1) and (2) have been characterized by DTA and TGA thermograms.

Journal ArticleDOI
TL;DR: The structures of two antitumor agents, 2-acetylpyridinethiosemicarbazone hemihydrate (1), C18H11N4O0.5S, colorless,M�� r�� 203.085 as mentioned in this paper, have been determined.
Abstract: The structures of two antitumor agents, 2-acetylpyridinethiosemicarbazone hemihydrate (1), C18H11N4O0.5S, colorless,M r 203.3, monoclinic,P21 lc,a=16.713(3),b=9.460(2),c=12.642(2) A, β=97.60(1)°,V=1981.2(6) A3,Z=8,R=0.054,R w =0.085 and 2-acetylpyridinethiosemicarbazone hydrochloride (2), C18H12N4SCl, yellow,M r =230.7, monoclinic,P21 ln,a=7.676(2),b=7.889(1),c=17.452(4), A, β=100.96(2)°,V=1037.5(4) A3 Z=4,R=0.041,R w =0.076, have been determined. Both compounds exhibit an E configuration(S atomtrans to the N atom of the hydrazine group). Three hydrogen bonds link the two crystallographically independent molecules in a pairwise fashion in the hemihydrate. An intramolecular N−H...Cl bond lends extra conformational stability to the hydrochloride salt.

Journal ArticleDOI
TL;DR: The mixed ligand complex, FeCl2(pyS)(Ph3P)2 characterized by X-ray crystallography was determined by the heavy atom method, using MoKα diffractometer data, and refined by full-matrix least squares toR=0.049 for 1123 observed reflections as mentioned in this paper.
Abstract: Attempts to prepare the mixed ligand complex, FeCl2(pyS)(Ph3P)2 from the reaction of iron(III) chloride with 2(1H)-pyridinethione-S(HpyS) and triphenylphosphine(Ph3P) in ethanol instead formed FeCl2(HPyS)2 characterized by X-ray crystallography. The structure was determined by the heavy atom method, using MoKα diffractometer data, and refined by full-matrix least squares toR=0.049 for 1123 observed reflections. The molecule possesses twofold symmetry with a distorted tetrahedral geometry about the iron(II) center with S-Fe-S and Cl-Fe-Cl bond angles of 98.76(5)° and 115.79(5)° and Fe-S and Fe-Cl bond distances 2.345(1) A and 2.288(1) A, respectively. Hydrogen bonding between NH and chlorine atoms leads to a polymeric type structure of linked molecules running approximately parallel to thea axis.

Journal ArticleDOI
TL;DR: The title compound, prepared in aqueous acetone, crystallizes in the monoclinic space group P21/n, with a=10.935(2),b=13.190(3),c=16.869(5) A,β=98.43(2)° andZ=4.057 for 1968 observed reflections as discussed by the authors.
Abstract: The title compound, prepared in aqueous acetone, crystallizes in the monoclinic space group P21/n, with a=10.935(2),b=13.190(3),c=16.869(5) A,β=98.43(2)° andZ=4. The structure was solved by direct methods and refined by full matrix least squares methods toR=0.057 for 1968 observed reflections. The complex is in the meridional conformation, with the Al atom coordinated to the bidentate 8-quinolinolato ligands in a distorted octahedral configuration. Acetone occluded in the lattice was converted to acetonylacetone during data collection; the latter was present in the ratio 0.25 molecules per mole of metal complex. The structure resembles the n-hexanol adduct of tris-(8-quinolinolato)manganese(III) with which the crystals are isomorphous.

Journal ArticleDOI
TL;DR: The pentakis ethylenediammonium bis undecachlorodiantimonate(III) tetrahydrate salt was solved by Patterson methods and refined to a finalR value of 0.023 for 4435 reflections withF 0>4σ(F 0).
Abstract: The pentakis ethylenediammonium bis undecachlorodiantimonate(III) tetrahydrate salt is monoclinic with the following unit cell dimensions:a=16.271(5) A,b=13.004(4) A,c=13.932(4) A, β=111.72(2)°, space groupP21/c withZ=2. The structure was solved by Patterson methods and refined to a finalR value of 0.023 for 4435 reflections withF 0>4σ(F 0). The structure shows a layer arrangement perpendicular to thea axis: planes of the [Sb2Cl11]5− bioctahedra alternate with planes of [NH3(CH2)2NH3]2+ dications. The [Sb2Cl11]5− bioctahedra are connected through O−H...Cl hydrogen bonds, such that infinite chains of composition [Sb2Cl11(H2O]n 5n− are formed in the structure, parallel to the twofold axis. These chains are themselves interconnected by means of N−H...Cl and O−H...Cl bonds originating from the [NH3(CH2)2NH3]2+ entities and the water molecules, respectively, and form a threedimensional network.

Journal ArticleDOI
TL;DR: The title compound (C20H16N2S3) as mentioned in this paper is monoclinic, witha=31.550(9),b=8.504(3),c=14.745(3) A,β=114.14 (3)°,Z=8 and space groupC2/c.
Abstract: The title compound (C20H16N2S3) is monoclinic, witha=31.550(9),b=8.504(3),c=14.745(3) A,β=114.14(3)°,Z=8 and space groupC2/c. The structure was solved by direct methods and refined toR=0.038 for 3012 reflections. The molecule exists in an uncommon conformation. Two quinoline moieties are nearly perpendicular to each other (80.9(3)°). Both methylthio groups have different orientation (the 4-SCH3 group is nearly perpendicular and the 3′-SCH3 is nearly coplanar to the quinoline moieties). Two pairs of sulfur atoms in ortho-positions remain in very close contact. The conformation of the molecule explains an unusual1H NMR spectrum.

Journal ArticleDOI
TL;DR: The title compound C16H10N5O7Li is triclinic, witha=1451(1),b=690(2),c=910(1) A,α=1015(1); β=671(2); γ=1056°(1).Z=2 and space groupP¯1 Data were measured by photographic methods.
Abstract: The title compound C16H10N5O7Li is triclinic, witha=1451(1),b=690(2),c=910(1) A,α=1015(1),β=671(2), γ=1056°(1),Z=2 and space groupP¯1 Data were measured by photographic methods The structure was solved by direct methods, and refined by full matrix least-squares The refinement, based on 1337 reflections, gave the rather highR value of 011 because of poor quality data The complex is dimeric The coordination around the cation is distorted square-pyramidal Two coordination sites are occupied by the nitrogen atoms of the bipyridyl ligand, two by the phenolic oxygen and oxygen ofo-nitro group, and the fifth coordination site is occupied by the phenolic oxygen belonging to the symmetry-related molecule (1−x,−y,1−z) Both oxygens act as bridges to form the dimer The bridging is unsymmetrical, with Li-O (phenolic)=184(2) A and Li1-O (phenolic)=216(2) A (whereI=1−x,−y, 1−Z)

Journal ArticleDOI
TL;DR: The structure of the title compound has been solved by direct methods, and refined to anR value of 0.035 for 1613 reflections as discussed by the authors, and the two pyridine rings are inclined at 61.4(2)° to each other.
Abstract: The structure of the title compound has been solved by direct methods, and refined to anR value of 0.035 for 1613 reflections. Both methyl carbon atoms deviate from the plane of the pyridine ring by 1.505(3) A in opposite directions. Both sulfur atoms S(1) and S(2) remain in short contact, at 3.247(1) A. The two pyridine rings are inclined at 61.4(2)° to each other.

Journal ArticleDOI
TL;DR: In this paper, the crystal structures of a spinacine intermediate, Nπ-hydroxymethyl-spinacine, and a spinaceamine derivative, Nα-methyl-spinaceamine, have been investigated through X-ray diffraction.
Abstract: The natural amino acid L-Spinacine (4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid) has been synthesized following a new pathway which gives a chemically and optically pure product with an excellent yield. The crystal structures of a synthetic intermediate, Nπ-hydroxymethyl-spinacine, and a spinacine derivative, Nα-methyl-spinaceamine, have been investigated through X-ray diffraction: Spi(πMeOH)·H2O, monoclinicP2 i,a=8.571(1),b=6.682(1),c=8.588(1) A, and β=94.67(1)o. Spm(αMe)·2HCl·H2O, triclinicP l,a=7.492(4),b=10.799(3),c=7.040(2) A, α=91.88(2), β=98.36(3) and γ=73.34(3)o. Spi(πMeOH) crystallizes with a water molecule and displays a zwitterionic character. The carboxylate group is in equatorial position and forms a short electrostatic interaction of 2.618(2) A between one of its oxygens and the protonated nitrogen of the tetrahydropyridine ring. The crystal packing is assured by strong O−H−−−O, O−H−−−N, N−H−−−N intermolecular hydrogen bonds and C−H−−−O close contacts. The biprotonated compounds Spm(αMe) crystallizes with two Cl− anions and a water molecule. The positive charge on the imidazole ring is delocalized on the conjugated moiety N=C−N. The crystal is built up by clusters formed by two biprotonated Spm(αMe) molecules, four Cl− anions and two water molecules linked together by hydrogen bonds.

Journal ArticleDOI
TL;DR: In this article, two-dimensional NMR spectroscopy in conjunction with X-ray crystallography was used to study the chair conformation of cyclohexane and trimethyl ester.
Abstract: cis,cis-Cyclohexane-1,3,5-tricarboxylic acid (1) its trimethyl ester (2) and their 1,3,5-trimethylated and 1,3,5-tribenzylated derivatives were prepared, and their structures studied by two-dimensional NMR spectroscopy in conjunction with X-ray crystallography. The results show that these molecules adopt a chair conformation in solution, with all the carboxyl groups in1 and all the methoxycarbonyl groups in2 occupying the equatorial positions, but with the corresponding functionalities in the alkylated derivatives occupying the axial positions. For2, its 1,3,5-tribenzylated derivative4, andcis,cis-1,3,5-trimethylcyclohexane-1,3,5-tricarboxylic acid (5), the same conformational preferences are seen to persist in the crystalline state as in solution.

Journal ArticleDOI
TL;DR: The structure of the π-molecular complex (10) was assigned on the basis of the solid state 13C-nmr spectrum of quinhydrone (12) as discussed by the authors.
Abstract: The structure of the π-molecular complex (10) was assigned on the basis of the solid state13C-nmr spectrum. The solid state13C-nmr spectrum of quinhydrone (12) has also been determined. Accurate1H and13C chemical shift assignments have been made for the compounds3,5,6,7,8, and10 on the basis of HMQC and HMBC spectral data. The π-molecular complex10 crystallizes in the space groupP21 In with cell parameters:a=4.052 (1) A,b=6.477 (1) A,c=19.093 (2) A, β=90.17 (1)o,z=1,D c =1.400 g mc−32. Crystal and molecular structure of the title compound, C28H22O4, has been determined by an X-ray analysis of10 by direct methods from diffractometer data and refined by full-matrix least-squares

Journal ArticleDOI
TL;DR: In this article, a dextrorotatory N-benzoyl-α-hydroxymethyltyrosine (α-HHS) was synthesized by a route involving α-HMS.
Abstract: α-Hydroxymethyltyrosine has been synthesized by a route involvingα-hydroxymethylation. Dextrorotatory N-benzoyl-α-hydroxymethyltyrosine4 crystallizes in space group P212121 with cell parameters:a=13.2266(9),b=16.1099(9),c=7.4475(5) A,V=15.86.9(2) A3,Z=4. The structure was solved by direct methods and refined toR=0.047 andR w =0.066 with 1549 independent and 956 $$\overline {hkl}$$ reflections. The absolute configuration of 1 was determined asR by the application of Hamilton test and by the estimation of the Bijvoet coefficientB. Just as in N-benzoyl-α-methylcysteine (Wieczorek et al., 1989), theα-amino acid residue adopts the C5 ring conformation similar to the fully extended form. The two side chains also adopt an extended conformation around the Cα atom.

Journal ArticleDOI
TL;DR: In this paper, the Cd atom coordinates to seven oxygens in a monocapped trigonal antiprism fashion, and the antiprisms share one vertex to form chains which run approximately parallel to the c axis.
Abstract: [Cd(C5H4O4)(OH2)2] (1), crystallizes in the monoclinic system, space groupP21/n, with lattice parametersa=7.323(2),b=16.028(6),c=7.202(2) A, β=113.11(1)°, andZ=4. The Cd atom coordinates to seven oxygens in a monocapped trigonal antiprism fashion. The antiprisms share one vertex to form chains which run approximately parallel to thec axis. The itaconate ligands link the chains to form layers which stack along theb axis.

Journal ArticleDOI
TL;DR: In this article, the structure of dibutyltin bisphenylacetate hydrate with a neutral ligand has been determined from 1211 ∥F¯¯0∥≥6σ∥F▬▬ c¯¯ ∥ MoKα reflections and refined to anR▬▬ Fcffff of 0.061 [space groupP2/a witha=8.416(2),b=10.28(1) A,β=98.42(4)° andZ=2].
Abstract: The Lewis acidity of tin in a diorganotin dicarboxylate is demonstrated in this first example of a 1/1 adduct of the ester with a neutral ligand. The structure of dibutyltin bisphenylacetate hydrate [(C4H9)2Sn(O2CCH2C6H5)2·H2O] has been determined from 1211 ∥F 0∥≥6σ∥F c ∥ MoKα reflections and refined to anR F of 0.061 [space groupP2/a witha=8.416(2),b=10.391(5),c=14.28(1) A,β=98.42(4)° andZ=2]. TheC α atoms [Sn-C 2.101(8) A; C-Sn-C 169.9(5)°] make up the apices and the Ocarboxylate [Sn-O 2.234(5), 2.439(7) A; O-Sn-O 55.7(2)°] and Owater [Sn-O 2.342(8) A] atoms the equatorial points of thetrans-C2SnO5 pentagonal bipyramid around the Sn atom. The molecular symmetry isC 2, and the Sn and Owater atoms lie along a crystallographic twofold axis. The aqua ligand forms donor H-bonds with neighboring carboxylato groups to link the molecules into a double zigzag chain running parallel toa.

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TL;DR: In this article, the 2-styrylpyridine has been crystallized from the condensation reaction between 2-methylpyridine with benzaldehyde in the formation of the model compound.
Abstract: We have crystallized the 2-styrylpyridine from the condensation reaction between the 2-methylpyridine with benzaldehyde in the formation of the model compound 2-styrylpyridine. The X-ray structure and NMR are currently reported. The main features of the structure is that is shows a localization of the double bonds rather than a delocalization of π electrons in an aromatic fashion.