Article

1999 ◽  
Vol 77 (5-6) ◽  
pp. 1057-1065
Author(s):  
John T Edward ◽  
Francis L Chubb ◽  
Denis FR Gilson ◽  
Rosemary C Hynes ◽  
Françoise Sauriol ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Acidic Solution ◽  
Variable Temperature ◽  
X Ray Diffraction ◽  
Nmr Studies ◽  
Cage Compounds ◽  
Amine Nitrogen ◽  
X Ray ◽  
Bridgehead Nitrogen ◽  
C Nmr

Three new cage peroxides, 1,6-diaza-3,4,8,9-tetraoxabicyclo[4.4.2]dodecane (3a),1,6-diaza-3,4,8,9-tetraoxa-11-methylbicyclo[4.4.2]dodecane (3b), and 1,6-diaza-3,4,8,9-tetraoxatricyclo[4.4.2.411,12]hexadecane (4), have been prepared by reaction of 1,2-diaminoethane, 1,2-diaminopropane, and trans-1,2-diaminocyclohexane, respectively, with formaldehyde and hydrogen peroxide in aqueous acidic solution. Their structures have been established by X-ray diffraction, and show the bridgehead nitrogen atoms to be predominantly sp2 hybridized. The structures accord with 1H and 13C NMR spectra. Variable temperature NMR studies show that the diperoxide 3a begins to undergo rapid inversion (on the NMR time scale) at about 303 K; up to 370 K the diperoxides 3b and 4 show no conformational change.Key words: cage compounds, formaldehyde, peroxides, amine nitrogen, hybridization.

Interactions de l'ion Ag+ avec la glutarimide

1984 ◽  
Vol 62 (7) ◽  
pp. 1287-1291 ◽  
Author(s):  
Johanne Perron ◽  
André L. Beauchamp
Keyword(s):  
Infrared Spectroscopy ◽  
Infrared Spectrum ◽  
Nmr Spectra ◽  
The Other ◽  
Mirror Plane ◽  
Bond Orders ◽  
X Ray Diffraction ◽  
Complex Species ◽  
X Ray ◽  
C Nmr

The 1:1 complex formed between Ag+ ions and glutarimide was investigated by X-ray diffraction, infrared spectroscopy, and 1H and 13C nmr. The crystals are monoclinic, C2/c, a = 13.497(3) Å, b = 9.503(2) Å, c = 9.600(4) Å, β = 92.30(3)°, Z = 4 molecules per cell. The structure was refined on 1086 nonzero [Formula: see text] reflections to R = 0.027. One half of the Ag atoms are linearly coordinated to the N atoms of two deprotonated glutarimide ligands, whereas the other half are surrounded by an approximate tetrahedron of four carbonyl oxygens belonging to two adjacent [Glu–Ag–Glu]− units. The [Glu–Ag–Glu]− groups are joined by tetrahedrally coordinated Ag atoms into infinite chains along the c axis. Complexation introduces a number of changes in the infrared spectrum of glutarimide. They can be related to the disappearance of the N—H vibrator and the change of bond orders in the —C(O)—N—C(O)— portion of the ligand. The nmr spectra show that coordinated glutarimide retains a mirror plane when the Ag complex is dissolved in DMSO. This suggests that the O-bonded Ag atoms dissociate to a large extent in solution, leaving the linear [Glu–Ag–Glu]− ions as the major glutarimide complex species.

Three-component Reaction of Cycloheptanone, 6-Amino-1,3-Dimethyluracil and Aromatic Aldehydes; X-Ray Structure, and Anti-inflammatory Evaluation of the Products

2008 ◽  
Vol 63 (9) ◽  
pp. 1117-1126 ◽  
Author(s):  
Mohamed I. Hegab ◽  
Nasser A. Hassan ◽  
Farouk M. E. Abdel-Megeid
Keyword(s):  
Schiff Bases ◽  
Aromatic Aldehydes ◽  
X Ray Diffraction ◽  
Nmr Studies ◽  
Reaction Conditions ◽  
X Ray ◽  
Three Component Reaction ◽  
The Given ◽  
First Time ◽  
C Nmr

1,3-Dimethyl-5-aryl-1,6,7,8,9,10-hexahydrocyclohepta[5,6]pyrido[2,3-d]pyrimidine-2,4-diones 4a, b (the linear regioisomers) and the Schiff bases, 6-N-benzylidenamino-1,3-dimethyluracil derivatives 5a, b, were isolated from a three-component reaction of cycloheptanone, 6-amino-1,3- dimethyluracil, and 4-chloro- or 4-bromobenzaldehyde. Surprisingly, 1,3-dimethyl-10-aryl-1,5,6,7, 8,9-hexahydrocyclohepta[4,5]pyrido-[2,3-d]pyrimidine-2,4-diones 6f, g (the angular regioisomers which are described for the first time in the literature under the given reaction conditions) and the Schiff bases, 6-N-benzylidenamino-1,3-dimethyluracil derivatives 5f, g, were isolated and characterized from the reaction with 4-methoxybenzaldehyde and 4-cyanobenzaldehyde. However, the three-component reaction of 6-amino-1,3-dimethyluracil, cycloheptanone, and 2-methoxybenzaldehyde afforded 1,3-dimethylbenzo[4,5]pyrido[3,2-d]pyrimidine-3,4-dione (7). Single crystal X-ray diffraction and 13C NMR studies of 4a and 6f provided support for the established structures. Some of the new products were tested for antiinflammatory activity comparable to indomethacin.

Synthesis and characterization of a series of 4-methyl-1-[2-aryl-1-diazenyl]-1,4-diazepanes and 1,4-di-[2-aryl-1-diazenyl]-1,4-diazepanes

2004 ◽  
Vol 82 (12) ◽  
pp. 1725-1735 ◽  
Author(s):  
Shasta Lee Moser ◽  
Keith Vaughan
Keyword(s):  
Nmr Assignments ◽  
Diazonium Salt ◽  
Variable Temperature ◽  
2D Nmr ◽  
Diazonium Salts ◽  
X Ray Diffraction ◽  
X Ray ◽  
New Compounds ◽  
C Nmr

1-Methylhomopiperazine was coupled with a series of diazonium salts to afford the 4-methyl-1-[2-aryl-1-diazenyl]-1,4-diazepanes (6), a new series of triazenes. These compounds are, in the main, stable crystalline solids (some of the series are stable oils), and they have been characterized by 1H and 13C NMR spectroscopy, IR spectroscopy, and mass spectrometry. NMR assignments were determined by 2D NMR and variable-temperature NMR experiments and by comparison with model compounds. A second series of new compounds, namely, 1,4-di-[2-aryl-1-diazenyl]-1,4-diazepanes (5), were prepared by coupling unsubstituted homopiperazine (1,4-diazepane) with 2 molar equivalents of the diazonium salt and were similarly characterized. The crystal and molecular structure of the parent member of this bis-triazene series (5, X = H) has been determined by single-crystal X-ray diffraction analysis.Key words: triazene, bis-triazene, diazenyl, bis-diazenyl, diazonium salt, NMR, diazepane.

[(Dimethylamino)methyl]ferrocene as an Amine Ligand: Study of the Bonding and X-Ray Crystal and Molecular Structure of the Pentacarbonyl{[(dimethylamino)methyl]ferrocene}tungsten Complex

2002 ◽  
Vol 67 (2) ◽  
pp. 228-234 ◽  
Author(s):  
Axel Fischer ◽  
Frank T. Edelmann ◽  
Klaus Jacob ◽  
Ivan Pavlík ◽  
Martin Pavlišta
Keyword(s):  
Molecular Structure ◽  
Single Crystal ◽  
Crystal And Molecular Structure ◽  
X Ray Diffraction ◽  
Amine Nitrogen ◽  
X Ray ◽  
Nmr Data ◽  
Amine Ligand ◽  
C Nmr

The heterodinuclear complex [W(CO)5(Me2NCH2Fc)] (Fc = ferrocenyl) (1) resulting from the reaction of [(dimethylamino)methyl]ferrocene (2) and [W(CO)6] was studied by single-crystal X-ray diffraction. Its molecular structure confirms the coordination of the amine nitrogen in 2 to tungsten (d(W-N) = 2.359(5) Å) and reveals its trans-influence in the W(CO)5 moiety. The structure is discussed in relation to several previously referred spectroscopic (IR, UV-VIS, 13C NMR) data.

Modes of Xanthine Complexation to Dirhodium Tetrakis[(R)-α-methoxy-α- (trifluoromethyl)-phenylacetate] in Solution and in the Solid State

2001 ◽  
Vol 56 (3) ◽  
pp. 319-324 ◽  
Author(s):  
Sven Rockitt ◽  
Rudolf Wartchow ◽  
Helmut Duddeck ◽  
Anna Drabczynska ◽  
Katarzyna Kiec-Kononowicz
Keyword(s):  
Solid State ◽  
Diffraction Analysis ◽  
Carbonyl Group ◽  
Enantiomeric Excess ◽  
Carbonyl Groups ◽  
X Ray Diffraction ◽  
Nmr Studies ◽  
X Ray ◽  
C Nmr

Abstract It is show n by IR and NMR studies that the xanthines 1-5 prefer a side-on com plexation to the chiral dirhodium tetrakis[(R)-α-methoxy-α-(trifluoromethyl)phenylacetatel (Rh*) in solution whereas carbonyl groups are involved in the solid state. For 6, at least the carbonyl group C-6 contributes to complexation in solution as well. A lternating strands of 6 and Rh* exist in the solid state as revealed by X-ray diffraction analysis described in detail. The determination of enantiomeric excess of the chiral xanthine 6 can easily be accomplished by the “dirhodium method ” (1H and 13C NMR in the presence of Rh*).

The crystal structure of cis-chlorobis(triethylphosphine)-1,8-naphthyridineplatinum(II) tetrafluoroborate, [PtCl(PEt3)2(naph)]BF4, a complex containing a monodentate 1,8-naphthyridine ligand

1978 ◽  
Vol 56 (4) ◽  
pp. 450-455 ◽  
Author(s):  
Gordon W. Bushnell ◽  
Keith R. Dixon ◽  
Masood A. Khan
Keyword(s):  
Crystal Structure ◽  
Variable Temperature ◽  
X Ray Diffraction ◽  
Nmr Studies ◽  
Interatomic Distances ◽  
X Ray ◽  
Heterocyclic Ligand ◽  
Square Planar ◽  
Cell Dimensions ◽  
R Value

The crystal structure of cis-chlorobis(triethylphosphine)-1,8-naphthyridineplatinum(II) tetrafluoroborate has been determined by single crystal X-ray diffraction and refined to an R-value of 0.063. The cell dimensions are a = 1.4246, b = 1.2676, c = 1.6530 nm, β = 115.66°. The space group is P21/c with 4 molecules per unit cell, and the measured density is 1.665 g cm−3. The structure is essentially a 4-coordinate square planar platinum(II) complex containing monodentate 1,8-naphthyridine. Interatomic distances to platinum are: Pt—Cl, 236.6(4); Pt—P(1), 225.4(4); Pt—P(2), 225.2(4); Pt—N(1), 208.3(11); and Pt—N(2), 304.5(14) pm. The structure is discussed in relation to variable temperature nmr studies of solutions, which indicate fluxional behaviour of the heterocyclic ligand.

scholarly journals Solid-state motion of OTeF5− compounds: detection by 19F NMR and IR spectroscopy and correlation with the X-ray structure of an orthorhombic crystalline modification of [C14H19N2+][OTeF5−] (C14H19N2+ = protonated 1,8-bis(dimethylamino)naphthalene)

1989 ◽  
Vol 67 (11) ◽  
pp. 2023-2029 ◽  
Author(s):  
Patti J. Kellett ◽  
Oren P. Anderson ◽  
Steven H. Strauss ◽  
Kent D. Abney
Keyword(s):  
Solid State ◽  
Nmr Spectra ◽  
Room Temperature ◽  
Variable Temperature ◽  
Structural Parameters ◽  
Crystalline Modification ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Triclinic Modification

An orthorhombic crystalline modification of [(PS)H+][OTeF5−] was studied by single crystal X-ray diffraction ((PS)H+ = protonated 1,8-bis(dimethylamino)naphthalene): orthorhombic, space group Cmcm, a = 8.607(2), b = 14.048(3), c = 13.365(2) Å, Z = 4, T = −130 °C. The structural parameters for the anion and cation in this modification (Mod-B) are very similar to those for the previously reported triclinic modification of this salt (Mod-A). However, variable temperature IR spectra for Mod-B suggest that the OTeF5− anion is exhibiting a two-site O/Fax interchange above −70 °C. Solid-state 19F NMR spectra suggest that this interchange may be as rapid as 104–105 s−1 at room temperature. Keywords: crystal structure of protonated 1,8-bis(dimethylamino)naphthalene)pentafluorotellurate(VI), polymorphism, solid state 19FNMR.

Diethyl 2-Benzimidazol-1-ylsuccinate–Picric Acid (1/1) – An Inclusion Molecular Complex

1997 ◽  
Vol 53 (6) ◽  
pp. 961-967 ◽  
Author(s):  
P. Zaderenko ◽  
M. S. Gil ◽  
P. López ◽  
P. Ballesteros ◽  
I. Fonseca ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Molecular Complex ◽  
Picric Acid ◽  
X Ray Diffraction ◽  
Nmr Studies ◽  
X Ray ◽  
H Nmr ◽  
Intramolecular Hydrogen ◽  
C Nmr

The crystal structure of the diethyl 2-benzimidazol-1-ylsuccinate–picric acid (1/1) molecular complex has been determined by X-ray diffraction analysis. Diethyl 2-benzimidazol-l-ylsuccinate molecules form channels along the a axis, in which the picric acid molecules are located. The benzimidazole moiety and the phenol group are held together by hydrogen bonding between the hydrogen of the phenol and the N3 atom of benzimidazole. Additionally, this hydrogen forms an intramolecular hydrogen bond with one O atom of the ortho-nitro group, thus producing a bifurcated hydrogen bond. 1H NMR spectra in DMSO-d 6 solution and CP/MAS solid 13 C NMR studies of this 2-benzimidazol-1-ylsuccinate–picric acid (1/1) molecular complex, as well as those of dimethyl, diethyl, di-n-butyl and 1-n-butyl-4-ethyl 2-imidazol-1-ylsuccinates, diethyl 2-pyrazol-1-ylsuccinate, ethyl imidazol-1-ylacetate, ethyl pyrazol-1-ylacetate and ethyl pyrazol-l-ylsuccinate, suggest that the picric acid linkage depends on the nature of the azole. Actual proton transfer is deduced for the imidazole derivatives, but only weak hydrogen bonding could be inferred for pyrazole derivatives.

Preparation and structure of oxo-rhenium(V) complexes with 7-azaindole

1993 ◽  
Vol 71 (12) ◽  
pp. 2060-2069 ◽  
Author(s):  
Anne-Marie Lebuis ◽  
André L. Beauchamp
Keyword(s):  
Hydrogen Bonds ◽  
Trans Isomer ◽  
Nmr Spectra ◽  
Binding Mode ◽  
Relative Orientation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxo Compounds ◽  
C Nmr

Four Re(V) oxo compounds were obtained from 7-azaindole (Haza) and ReOCl3(PPh3)2: the oxo-bridged dimer Re2O3Cl4(Haza)4 (1), the oxo–ethoxo monomers ReO(OEt)Cl2(Haza)2 (2) and ReO(OEt)Cl2(Haza)(PPh3) (3), and the dioxo [ReO2(Haza)4]Cl salt (4a). [ReO2(Haza)4]I (4b) was also prepared from ReO2I(PPh3)2. The ReO(OEt)Cl2(Haza)2 complex was shown by X-ray diffraction (C2/c, a = 16.292, b = 9.395, c = 12.104 Å, β = 101.47°, R = 0.041) to consist of individual molecules of the trans-trans isomer in which azaindole is N7-bonded. Crystals of [Formula: see text] (C2/m a = 15.422, b = 13.055, c = 9.086 Å, β = 91.13°, R = 0.059) contain well separated Cl− anions and trans-dioxo cations. The N7-bonded azaindole ligands are held parallel to the O=Re=O direction by intramolecular [Formula: see text] hydrogen bonds, but the relative orientation of the four ligands cannot be determined because of disorder. Characteristic Re—oxygen vibrations are observed in infrared for each type of compounds. The 1H and 13C NMR spectra are discussed in relation with the azaindole binding mode.

scholarly journals Sessilifol A and B, Urease Inhibitory Pimarane-type Diterpenes from Hymenocrater sessilifolius

2017 ◽  
Vol 12 (12) ◽  
pp. 1934578X1701201
Author(s):  
Sadia Khan ◽  
Muhammad Shaiq Ali ◽  
Zeeshan Ahmed ◽  
Mehreen Lateef ◽  
Sammer Yousuf ◽  
...  
Keyword(s):  
Single Crystal ◽  
Vanillic Acid ◽  
Nmr Spectra ◽  
Soluble Fraction ◽  
2D Nmr ◽  
X Ray Diffraction ◽  
X Ray ◽  
Inhibitory Potential ◽  
Urease Inhibitory ◽  
C Nmr

New pimarane type diterpenes named sessilifol A (1) and B (2) have been isolated from the EtOH soluble fraction of Hymenocrater sessilifolius Benth., along with eight known constituents cirsimaritin (3), gardenin C (4), β-sitosterol (5), saringosterol (6), β-sitosterol glucoside (7), ursolic acid (8), sucrose (9) and vanillic acid (10). Their structures were elucidated on the basis of 1H- and 13C-NMR spectra and by 2D-NMR experiments. The structure of 1 was further confirmed by single crystal X-ray diffraction technique. The compound 2 showed potent inhibitory potential against the enzyme urease while 1, 3, 4 and 10 were moderately active.

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