Molecular conformation of 2′-deoxy-3′,5′-di-O-acetyl guanosine. Crystal structure and high resolution proton nuclear magnetic resonance investigations

1988 ◽  
Vol 66 (10) ◽  
pp. 2634-2639 ◽  
Author(s):  
Leo H. Koole ◽  
Henk M. Buck ◽  
Jan A. Kanters ◽  
Arie Schouten
Keyword(s):  
Molecular Conformation ◽  
Proton Nuclear Magnetic Resonance ◽  
Solution Conformation ◽  
Planar System ◽  
Equal Distribution ◽  
Triclinic Space Group ◽  
X Ray ◽  
H Nmr ◽  
Conformational Preferences ◽  
Cell Dimensions

2′-Deoxy-3′,5′-di-O-acetyl guanosine crystallizes in the triclinic space group [Formula: see text], and the cell dimensions are a = 8.643(1) Å, b = 10.122(1) Å, c = 10.391(1) Å, α = 87.04(1)°, β = 73.58(1)°, γ = 72.37(1)°, V = 830.4(2) Å3; Z = 2 molecules per cell. Least-squares refinement converged at R = 0.031 for 3450 observed reflections. The asymmetric unit consists of two independent molecules. The guanine bases are linked via N(1)—H … N(7) and N(2)—H … O(6) hydrogen bonds to form a virtually planar system. Moreover, the conformational preferences of the title compound in DMSO-d6 solution have been determined with 300 MHz 1H NMR. It is found that the X-ray structure and the solution conformation are essentially similar. The C(4′)—C(5′) linkage resides in the gauche+ (g+) or trans (t) rotamers in the solid state, while an approximately equal distribution over g+, t, and gauche− is found in solution.

Molecular conformation of 2′-deoxy-3′,5′-di-O-acetyl adenosine. Crystal structure and high resolution proton nuclear magnetic resonance investigations

1987 ◽  
Vol 65 (2) ◽  
pp. 326-331 ◽  
Author(s):  
Leo H. Koole ◽  
Henk M. Buck ◽  
Jan A. Kanters ◽  
Arie Schouten
Keyword(s):  
Crystal Structure ◽  
Molecular Conformation ◽  
Proton Nuclear Magnetic Resonance ◽  
Solution Conformation ◽  
Orthorhombic Space Group ◽  
One Dimensional ◽  
X Ray ◽  
H Nmr ◽  
Conformational Preferences ◽  
Cell Dimensions

2′-Deoxy-3′,5′-di-O-acetyl adenosine crystallizes in the orthorhombic space group P212121, and the cell dimensions are a = 7.768(1) Å, b = 12.890(1) Å, c = 15.495(1) Å; Z = 4 molecules per cell. Least-squares refinement converged at R = 0.054 for 1752 observed reflections. The adenine bases are linked via N6—H … N1 and N6—H … N7 hydrogen bonds, in such a way that infinite one-dimensional chains are formed. Comments are made on the fact that this structure is entirely different from the parallel dimer that was found for 3′,5′-di-O-acetyl thymidine. Furthermore, the conformational preferences of the title compound in aqueous solution have been determined with 300- and 500-MHz 1H nmr. It is found that the X-ray structure and the solution conformation are essentially similar, except for the C4′—C5′ conformation, that is γ− in the solid state, and predominantly γ+ in solution.

Synthesis and structural study of aminals derived from 8-aminoquinoline and 1-aminonaphtalene

1987 ◽  
Vol 65 (4) ◽  
pp. 687-692 ◽  
Author(s):  
Enrique Galvez ◽  
Isabel Iriepa ◽  
Antonio Lorente ◽  
Jose Miguel Mohedano ◽  
Feliciana Florencio ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Carbon Atom ◽  
Mass Spectra ◽  
The Other ◽  
Reaction Conditions ◽  
Schiff’S Base ◽  
Triclinic Space Group ◽  
X Ray ◽  
H Nmr ◽  
Cell Dimensions

Reaction of 8-aminoquinoline with pyridine-2-carboxaldehyde (2), pyridine-3-carboxaldehyde (3), pyridine-4-carboxaldehyde (4), and benzaldehyde (5) yields the corresponding aminals or Schiff's bases according to reaction conditions; analogous results are obtained from the reaction of 1-amino-naphtalene with pyridine-2-carboxaldehyde (6). On the other hand, reaction of 8-aminoquinoline with thiophene-2-carboxaldehyde or pyrrole-2-carboxaldehyde yields neither the aminal nor the Schiff's base. Crystals of 4 (C24H19N5) belong to the triclinic space group [Formula: see text]. Cell dimensions are a = 11.547(3), b = 11.759(2), c = 15.687(5) Å, α = 98.50(2)°, β = 101.61(2)°, γ = 107.28(2)°, V = 1942.6(9) Å3. Final R = 0.077 and Rw = 0.064; 3160 reflections were observed. The ir, 1H nmr of 2–6, the mass spectra of 4 and 5 and the X-ray analysis of 4 are described and discussed. Preparative features, ir, 1H nmr, analyses and crystal structure indicate that the formation of 2–6 are governed mainly by the nucleophilicity at the aldehyde carbon atom and the existence of the hydrogen bonds in the aminal.

X-ray and 1H nmr analyses of 5-(m-benzyloxybenzyl)-1-[(1,3-dihydroxy-2-propoxy)methyl]uracil, an acyclonucleoside inhibitor of uridine phosphorylase

1986 ◽  
Vol 64 (12) ◽  
pp. 2376-2381 ◽  
Author(s):  
George I. Birnbaum ◽  
Jean-Robert Brisson ◽  
Shi Hsi Chu ◽  
Zhi Hao Chen ◽  
Elizabeth C. Rowe
Keyword(s):  
Direct Methods ◽  
Uridine Phosphorylase ◽  
Hydrogen Atoms ◽  
Gauche Conformation ◽  
Triclinic Space Group ◽  
X Ray ◽  
H Nmr ◽  
Cell Dimensions ◽  
Nuclear Overhauser ◽  
Glycosidic Torsion Angle

The title compound crystallizes in the triclinic space group [Formula: see text] and the cell dimensions are a = 16.890(3), b = 9.586(2), c = 6.316(1) Å, α = 91.09(1), β = 93.50(1), γ = 93.04(1)°. X-ray intensity data were measured on a diffractometer, and the crystal structure was determined by direct methods. Least-squares refinement, which included all hydrogen atoms, converged at R = 0.056 for 3454 observed reflections. Adjacent six-membered rings are approximately perpendicular to one another. The glycosidic torsion angle [C(6)—N(1)—C(1′)—O(4′)] is 96.2(2)°. In the acyclic moiety, both C—OH bonds are gauche with respect to C(4′)—O(4′). The gauche conformation is also dominant in solution, as determined by high-resolution 1H nmr spectroscopy. Results of nuclear Overhauser experiments lead to conclusions about the flexibility of the molecule.

Supramoleküle aus Kronenethern und geminalen Sulfonen: Synthese von vier binären Komplexen und Kristallstruktur von (CH2CH2O)4·2H 2C(SO2C2H5)2/Supramolecules of Crown Ethers with Geminal Sulfones: Synthesis of Four Binary Complexes and Crystal Structure of (CH2CH2O )4·2H2C(SO2C2H5)2

1995 ◽  
Vol 50 (7) ◽  
pp. 1018-1024 ◽  
Author(s):  
Axel Michalides ◽  
Dagmar Henschel ◽  
Armand Blaschette ◽  
Peter G. Jones
Keyword(s):  
Monoclinic Space Group ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Binary Complexes ◽  
Cyclic Polyethers ◽  
Adjacent Unit ◽  
Methylene Group

In a systematic search for supramolecular complexes involving all combinations of the cyclic polyethers 12-crown-4 (12C4), 15-crown-5 (15C 5), 18-crown-6 (18C 6) and dibenzo- 18-crown-6 (DB -18C6), and the geminal di- or trisulfones H2C(SO 2Me)2, H2C (SO2Et)2 and HC (SO2Me)3-n (SO2Et)n (n = 0 -3 ) , only the following four complexes could be isolated and unequivocally characterized by elemental analysis and 1H NMR spectroscopy: [(12C4){H2C (SO2Et)2}2] (3), [(18C6){H2C (S O2Me)2}] (4), [(DB -18C 6){H2C (SO2Et)2}] (5) and [(D B -18C 6)2{HC (SO2Me )(SO2Et)2}3] (6). The structure of 3 (triclinic, space group P1̄) consists of crystallographically centrosymmetric formula units, in which the disulfone molecules are bonded on each side of the ring by two C -H ··· O(crown) interactions originating from the central methylene group (H···O 213 pm) and from the methylene group of one EtSO2 moiety ( H ··· O 237 pm). Formula units related by translation are connected into parallel strands by a third type of reciprocal C -H ···O bond (H ···O 232 pm) between the second H atom of the central methylene group and a sulfonyl oxygen atom of the adjacent unit. The structure of 4 (monoclinic, space group C2/c) showed severe disorder of the crown ether and could not be refined satisfactorily. Compounds 5 and 6 crystallized as long and extremely thin fibres, indicative of linear-polymeric supramolecular structures; single crystals for X-ray crystallography were not available.

Configurational and conformational studies on condensation products of biogenic amines with 2,5-anhydro-D-mannose

1985 ◽  
Vol 63 (11) ◽  
pp. 2915-2921 ◽  
Author(s):  
Ian M. Piper ◽  
David B. MacLean ◽  
Romolo Faggiani ◽  
Colin J. L. Lock ◽  
Walter A. Szarek
Keyword(s):  
Hydrogen Bond ◽  
Intermolecular Hydrogen Bond ◽  
Direct Methods ◽  
Conformational Studies ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Twist Conformation ◽  
Cell Dimensions ◽  
Internal Hydrogen Bond

The products of a Pictet–Spengler condensation of tryptamine and of histamine with 2,5-anhydro-D-mannose have been studied by X-ray crystallography to establish their absolute configuration. 1(S)-(α-D-Arabinofuranosyl)-1,2,3,4-tetrahydro-β-carboline (1), C16H20N20O4, is monoclinic, P21 (No. 4), with cell dimensions a = 13.091(4), b = 5.365(1), c = 11.323(3) Å, β = 115.78(2)°, and Z = 2. 4-(α-D-Arabinofuranosyl)imidazo[4,5-c]-4,5,6,7-tetrahydropyridine (3), C11H17N3O4, is orthorhombic, P212121 (No. 19), with cell dimensions a = 8.118(2), b = 13.715(4), c = 10.963(3) Å, and Z = 4. The structures were determined by direct methods and refined to R1 = 0.0514, R2 = 0.0642 for 3210 reflections in the case of 1, and to R1 = 0.0312, R2 = 0.0335 for 1569 reflections in the case of 3. Bond lengths and angles within both molecules are normal and agree well with those observed in related structures. In 3 the base and sugar adopt a syn arrangement, which is maintained by an internal hydrogen bond between O(2′) and N(3). The sugar adopts a normal 2T3 twist conformation. The sugar has the opposite anti arrangement in the β-carboline 1 and the conformation of the sugar is unusual; it is close to an envelope conformation with O(4′) being the atom out of the plane. This conformation is caused by a strong intermolecular hydrogen bond from O(5′) in a symmetry-related molecule to O(4′). Both compounds are held together in the crystal by extensive hydrogen-bonding networks. The conformations of the compounds in solution have been investigated by 1H nmr spectroscopy, and the results obtained were compared with those obtained by X-ray crystallography for 1 and 3.

Platin in seiner ungewöhnlichen Oxidationsstufe + III: Diplatin(III)-Komplexe der Modellnukleobase 1-Methyluracil / Platinum in its Unusual Oxidation State + III: Diplatinum(III) Complexes with the Model Nucleobase 1-Methyluracil

1983 ◽  
Vol 38 (11) ◽  
pp. 1441-1445 ◽  
Author(s):  
Bernhard Lippert ◽  
Helmut Schöllhorn ◽  
Ulf Thewalt
Keyword(s):  
Crystal Structure ◽  
Nitric Acid ◽  
Ir Spectra ◽  
Oxidation State ◽  
Structural Similarity ◽  
Single Bond ◽  
Triclinic Space Group ◽  
H Nmr ◽  
Axial Ligands ◽  
Cell Dimensions

Oxidation of the head-tail dimer cis-[(NH3)2Pt(1-MeU)]2(NO3)2 (1-MeU = 1-methyl - uracilato anion, C5H5N2O2) with a mixture of nitrous and nitric acid yields three crystalline species, [(NO2)(NH3)2Pt(C5H5N2O2)2Pt(]SrH3)2(NO2)](NO3)2 · 3 H2O (1), [(H2O)(NH3)2Pt(C5H5N2O2)2Pt(]SrH3)2(NO2)](NO3)2 · 5 H2O (2) and [(NO3)(NH3)2Pt(C5H5N2O2)2Pt(]SrH3)2(NO3)](NO3)2 · 4.5 H2O (3). The crystal structure of 2 has been determined. 2 crystallizes in the triclinic space group P1̄ with cell dimensions a= 11.959(4), b= 11.560(3), c= 11.261(2) Å, α = 89.16(2), β= 104.36(2), γ = 99.61(2)° and Z = 2. The structure was refined to R = 0.056, Rw = 0.061 on 4311 reflections. The Pt-Pt distance within the dinuclear cation of 2 is 2.574(1) Å and cor­responds to a Pt-Pt single bond. The axial ligands are N̲O2 (Ptl) and O̲H2 (Pt2), the equatorial ligands two NH3 groups, N 3 and O4 of 1-MeU for both Pt atoms. The oxidation state of Pt in 2 is +III. 1H NMR and IR spectra of 1, 2, and 3 reveal a close structural similarity of the three compounds.

scholarly journals Chemie polyfunktioneller Moleküle, 114 [1]. Synthese und Struktur eines ionischen und nichtionischen, cyclischen Carbaphosphazens und eines Cobalt(III)phosphazen-Komplexes / Chemistry of Polyfunctional Molecules, 114 [1]. Synthesis and Structure of an Ionic and Non Ionic Cyclic Carbaphosphazene and of a Cobalt(III)phosphazene Complex

1994 ◽  
Vol 49 (12) ◽  
pp. 1763-1773 ◽  
Author(s):  
Jochen Ellermann ◽  
Jörg Sutter ◽  
Falk A. Knoch ◽  
Matthias Moll ◽  
Walter Bauer
Keyword(s):  
Mass Spectra ◽  
Monoclinic Space Group ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Lattice Constants ◽  
H Nmr

Reaction of (1) in CH2Cl2 with benzimidazole yields . The salt [4]+BPh4- has been prepared in THF by metathesis of [4]+Cl- with NaBPh4. Deprotonation of the cationic ring in [4]+BPh4- was accomplished using 1,8-diazabicyclo[5.4.01,7]undec-7-ene and resulted in the six-membered carbacyclophosphazene (6). Treating 1 with 8 -hydroxyquinoline in CH2Cl2 yields the octahedral cis-complex = 8-oxyquinolinate group). The com pounds [4]+BPh4-, 6 and 7 are characterized by their IR, Raman, 31P{1H} NMR, 13C{1H} NMR, 1H NMR and mass spectra. Crystals suitable for X-ray structure analyses have been obtained for [4]+BPh4- and 7×0.5 CH2Cl2. The colourless plates of [4]+BPh4- crystallize in the triclinic space group P1̄, with the lattice constants a = 1172.7(3), b = 1326.2(3), c = 1806.1(6) pm; α = 100.79(2), β = 103.71(3), γ = 108.18(2)°. The black blocks of 7×0.5 CH2Cl2 crystallize in the monoclinic space group P 21/c with the lattice constants a = 1159.0(10), b = 2008.9(10), c = 2034.6(12) pm; β = 105.86(5)°.

Synthesis, Crystal Structure and Magnetic Properties of a Copper(II) p-Formylbenzoate Complex

2012 ◽  
Vol 67 (11) ◽  
pp. 1185-1190 ◽  
Author(s):  
Jin-Li Qi ◽  
Wei Xu ◽  
Yue-Qing Zheng
Keyword(s):  
Room Temperature ◽  
Magnetic Measurements ◽  
X Ray Diffraction ◽  
Complex Molecules ◽  
Triclinic Space Group ◽  
X Ray ◽  
Cell Dimensions ◽  
Ferromagnetic Interactions ◽  
Aqueous Conditions ◽  
Discrete Complex

A new Cu(II) complex was prepared at room temperature from the reaction of p-formylbenzoic acid, phenanthroline, CuCl2⋅2H2O, and NaOH under ethanolic aqueous conditions. The complex has been characterized by X-ray diffraction, IR spectroscopy, TG-DTA analyses, and magnetic measurements. Single-crystal X-ray diffraction analysis indicated that the complex crystallizes in the triclinic space group P1̄ with the cell dimensions a=7.875(2), b=10.724(2), c=15.317(3) Å , α =102.65(3), β =93.71(3), γ =107:64(3)°. The Cu atoms are in the environment of distorted CuN2O3 tetragonal pyramids. These discrete complex molecules are packed through intermolecular π...π-stacking interactions and C-H...O hydrogen bonds forming a supramolecular structure. The title complex obeys the Curie-Weiss law with a Curie constant C=0:53 cm3 K mol-1 and a Weiss constant θ = -0:27 K. The shape of the xmT curve is characteristic of weak ferromagnetic interactions between the Cu(II) centers from 300 to 7 K, while there are weak antiferromagnetic interactions below 7 K.

scholarly journals Synthesis And Structural Characterization Of 1-Butyl-2,3-Dimethylimidazolium Bromide And Iodide

2007 ◽  
Vol 62 (6) ◽  
pp. 868-870 ◽  
Author(s):  
Johanna Kutuniva ◽  
Raija Oilunkaniemi ◽  
Risto S. Laitinen ◽  
Janne Asikkala ◽  
Johanna Kärkkäinen ◽  
...  
Keyword(s):  
Unit Cell ◽  
Monoclinic Crystal System ◽  
Monoclinic Crystal ◽  
Space Group ◽  
X Ray ◽  
Crystal System ◽  
H Nmr ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

1-Butyl-2,3-dimethylimidazolium bromide {(bdmim)Br} (1) and iodide {(bdmim)I} (2) were prepared conveniently by the reaction of 1,2-dimethylimidazole and the corresponding 1-halobutane. The compounds were characterized by 1H and 13C{1H} NMR spectroscopy as well as by X-ray single crystal crystallography. 1 crystallizes in the monoclinic crystal system, space group P21/n, with Z = 4, and unit cell dimensions a = 8.588(2), b = 11.789(1), c = 10.737(2) Å, β = 91.62(3)°. Compound 2 crystallizes in the monoclinic crystal system, space group P21/c, with Z = 8, and unit cell dimensions a = 10.821(2), b = 14.221(3), c = 15.079(2) Å , β = 90.01(3)°. The lattices of the salts are built up of 1-butyl-2,3- dimethylimidazolium cations and halide anions. The cations of 1 form a double layer with the imidazolium rings stacked together due to π interactions. The Br− anions lie approximately in the plane of the imidazolium ring, and the closest interionic Br···H contacts span a range of 2.733(1) - 2.903(1) Å. Compound 2 shows no π stacking interactions. The closest interionic I···H contacts are 2.914(1) - 3.196(1) Å

Metal-selenolate chemistry: stereochemistry of adamantane-type clusters of formula [(μ-SePh)6(MSePh)4]2− (M = Zn and Cd)

1992 ◽  
Vol 70 (3) ◽  
pp. 792-801 ◽  
Author(s):  
Jagadese J. Vittal ◽  
Philip A. W. Dean ◽  
Nicholas C. Payne
Keyword(s):  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Bridging Ligands ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Space Groups ◽  
X Ray Crystallography ◽  
Cell Dimensions ◽  
Minimum Number

The structures of three tetramethylammonium salts containing anions of formula [(μ-SePh)6(MSePh)4]2− (M = Zn and Cd) were determined by single crystal X-ray diffraction techniques. The Zn salt crystallizes in different space groups depending upon the solvent combination used in the synthesis. Thus crystals of (Me4N)2[Zn4(SePh)10], 1, grown from a mixture of methanol, acetonitrile, and acetone are triclinic, space group [Formula: see text] with cell dimensions a = 13.214(2), b = 23.859(2), c = 13.072(1) Å, α = 91.134(8), β = 113.350(8), γ = 79.865(9)°, and Z = 2. In the absence of acetone, a solvated crystal (Me4N)2[Zn4(SePh)10]•CH3CN, 2, is formed, which belongs to the monoclinic space group P21/n with a = 14.248(1), b = 39.722(2), c = 13.408(1) Å, β = 97.132(5)°, and Z = 4. The Cd salt (Me4N)2[Cd4(SePh)10], 3, crystallizes in the monoclinic space group P21/c, with a = 20.830(2), b = 14.282(1), c = 25.872(1) Å, β = 99.626(6)°, and Z = 4. These three salts are the first examples of homoleptic, tetranuclear selenolatometal(II) anions with (μ-Se)6M4 cages of adamantane-type stereochemistry. In each case the phenyl substituents of the bridging ligands adopt the configuration [aae, aae, aee, aee], which has the minimum number of two 1,3-axial–axial non-bonding substituent interactions. Keywords: selenolate complexes, synthesis, X-ray crystallography, isomerism, adamantane stereochemistry.

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