scholarly journals Tautomerisation in 1-(4-Methylphenylazo)naphthalen-2-ol and 2-(4-Methylphenylazo)-4-methylphenol: A Crystallographic and 13C{1H}NMR Study

1999 ◽  
Vol 23 (3) ◽  
pp. 178-179
Author(s):  
Wendy I. Cross ◽  
Kevin R. Flower ◽  
Robin G. Pritchard
Keyword(s):  
Acetic Acid ◽  
Nmr Spectroscopy ◽  
Resonant Frequency ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Nmr Study ◽  
Acetic Acid Esters ◽  
Acid Esters ◽  
Equivalent Carbon

The acetic acid esters of 1-(4-methylphenylazo)naphthalen-2-ol 1 and 2-(4-methylphenylazo)-4-methylphenol 3 are prepared and characterised by single crystal X-ray diffraction studies and 13C{1H}NMR spectroscopy; the position of the C(2)13C resonance for the ester is used to predict the position of resonant frequency of the equivalent carbon in the parent alcohols and hence, calculate the position of the azo-hydrazone equilibrium in these compounds.

An unusual reaction of a bridged triterpenoid α-diketone with acetic anhydride

1991 ◽  
Vol 56 (12) ◽  
pp. 2917-2935 ◽  
Author(s):  
Eva Klinotová ◽  
Václav Křeček ◽  
Jiří Klinot ◽  
Miloš Buděšínský ◽  
Jaroslav Podlaha ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Nmr Spectroscopy ◽  
Acetic Anhydride ◽  
Spectral Methods ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mild Conditions ◽  
Condensation Products ◽  
Unsaturated Lactones ◽  
C Nmr

3β-Acetoxy-21,22-dioxo-18α,19βH-ursan-28,20β-olide (IIIa) reacts with acetic anhydride in pyridine under very mild conditions affording β-lactone IVa and γ-lactones Va and VIIa as condensation products. On reaction with pyridine, lactones Va and VIIa undergo elimination of acetic acid to give unsaturated lactones VIIIa and IXa, respectively. Similarly, the condensation of 20β,28-epoxy-21,22-dioxo-18α,19βH-ursan-3β-yl acetate (IIIb) with acetic anhydride leads to β-lactone IVb and γ-lactone Vb; the latter on heating with pyridine affords unsaturated lactone VIIIb and 21-methylene-22-ketone Xb. The structure of the obtained compounds was derived using spectral methods, particularly 1H and 13C NMR spectroscopy; structure of lactone IVa was confirmed by X-ray diffraction.

scholarly journals Synthesis, Structure, and Properties of a Dinuclear Cu(II) Coordination Polymer Based on Quinoxaline and 3,3-Thiodipropionic Acid Ligands

2021 ◽  
Author(s):  
Adedibu Clement Tella ◽  
Samson Owalude ◽  
Vincent Adimula ◽  
Adetola Oladipo ◽  
Victoria Olayemi ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Nitrogen Atom ◽  
Coordination Polymer ◽  
Elemental Analysis ◽  
Catalytic Reduction ◽  
Copper Acetate ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr

Abstract The coordination polymer [Cu2(TDPH)4(QNX)].DMF, (QNX = Quinoxaline; TDPH = 3,3-thiodipropionic acid), has been prepared by reaction of copper acetate, TDPH, and quinoxaline. The compound was characterized by elemental analysis, FTIR spectroscopy, and single-crystal X-ray diffraction. The crystal is monoclinic with a P21/n space group and dimensions of a = 12.889(3) Å, b = 14.983(4) Å, c = 14.091(3) Å, α = 90 °, β = 90.200(11) °, γ = 90 °, V = 2721.18 (2) Å3, Z = 4. The ligands are hexagonally coordinated to the Cu(II) centre in the form of Cu2O4N with one nitrogen atom from the quinoxaline ligand, and four oxygen atoms from four TDPH molecules in a monodentate fashion. The Cu-Cu bond length was 2.642(1) and 2.629(1) Å for the Cu1----Cu1 and Cu2----Cu2 bonds. The QNX ligand bridged the two copper atoms. The catalytic reduction of 4-nitrophenol to 4-aminophenol using NaBH4 in the presence of [Cu2(TDPH)4(QNX)].DMF, as catalyst was completed within 11 minutes. The 4-aminophenol product was confirmed using 1H NMR spectroscopy.

Investigation of the disorder of dibromo- and dichloromethane in their tri-ortho-thymotide clathrates using X-ray diffraction and solid-state 2H NMR spectroscopy

2011 ◽  
Vol 89 (7) ◽  
pp. 854-862
Author(s):  
Glenn A. Facey ◽  
Ilia Korobkov
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Guest Molecule ◽  
Type B ◽  
X Ray Diffraction ◽  
Guest Molecules ◽  
X Ray ◽  
Twofold Axis ◽  
H Nmr ◽  
Heavy Atoms

The tri-ortho-thymotide (TOT) clathrates of dibromo- and dichloromethane were characterized by single crystal X-ray diffraction at 200 K and solid-state 2H NMR spectroscopy as a function of temperature. The host structure was found to be typical of other cage-type TOT clathrates. The X-ray results showed a substantial amount of disorder among the guest molecules. In both clathrates, multiple guest molecule positions could be modeled. The heavy atoms of all the guest molecule positions lie approximately in the same plane, with some out-of-plane distortion. The guest molecules were of two different types in positions symmetric about the crystallographic twofold rotation axis: type A guests, with carbon atoms well removed from the crystallographic twofold axis, and type B guests, with carbon atoms very close to the twofold axis. The 2H NMR spectra for the guests confirmed that the disorder was dynamic. The experimental results could be accounted for by the presence of three simultaneous types of molecular motion, all fast with respect to the 2H quadrupolar interaction: (i) twofold molecular flips about the molecular C2 symmetry axis, (ii) exchange between the type A and type B sites in a single plane, and (iii) a two-site libration of the plane containing the heavy atoms of the A and B guest sites with a temperature-dependent amplitude.

Sila-Pharmaka, 26. Mitt. [1]. Darstellung und Eigenschaften potentiell curarewirksamer Silicium-Verbindungen, III / Sila-Pharmaca, 26th Communication [1]. Preparation and Properties of Silicon Compounds with Potential Curare-Like Activity, III

1982 ◽  
Vol 37 (11) ◽  
pp. 1461-1471 ◽  
Author(s):  
Reinhold Tacke ◽  
Haryanto Linoh ◽  
Moayad T. Attar-Bashi ◽  
William S. Sheldrick ◽  
Ludger Ernst ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Neuromuscular Blocking ◽  
Neuromuscular Blocking Agents ◽  
X Ray Diffraction ◽  
Silicon Compounds ◽  
X Ray ◽  
Structure Activity Relationships ◽  
H Nmr ◽  
Structure Activity

The potentially curare-like silicon compounds 8a-8f wore synthesized and investigated with respect to their structure-activity relationships. The conformations of the com­pounds in the solid state and in solution were studied by X-ray diffraction analysis (8a-8e) and 1H NMR spectroscopy (8a-8f), respectively. The muscle relaxing properties of 8a-8f were investigated on the mouse. The observed structure-activity relationships are not in accordance with the classical “14 Å model” for neuromuscular blocking agents.

Über Inhaltsstoffe von Euphorbiaceae, 8. Mitt. [1]. Triterpenester und Triterpenalkohole aus Euphorbia biglandulosa Desf. / Constituents of Euphorbiaceae, 8. Comm. [1]. Triterpen Esters and Triterpen Alcohols from Euphorbia biglandulosa Desf.

1985 ◽  
Vol 40 (4) ◽  
pp. 553-555 ◽  
Author(s):  
Gioacchino Falsone ◽  
Claudia Schneider
Keyword(s):  
Fatty Acids ◽  
Acetic Acid ◽  
H Nmr ◽  
Acetic Acid Esters ◽  
Acid Esters

Fatty acids and acetic acid esters of lanosterol and cycloartenol and triterpens alcohols were isolated from the latex of Euphorbia biglandulosa Desf. The triterpenesters were identified as (E,Z)-2,4-decadienoyllanosterol (1a), (E,Z)-2,4-octadienoyllanosterol (1b), (E,Z)-2,4-oc- tadienoylcycloartenol (2a), (2E,4Z)-2,4,6-decatrienoyllanosterol (1c), (2E,4Z)-2,4,6-deca- trienoylcycloartenol (2b), lanosterylacetat (1d) and cycloartenylacetat (2c) by IR-, 1H-NMR- and MS-spectroscopy and hydrolysis. The triterpens alcohols were identified as butyrospermol, cyclo­artenol, 24-methylencycloartanol and obtusifoliol.

1H NMR study of the solvolysis of the paramagnetic tetrachloro-bis(imidazole)ruthenium(III) anion in water, methanol, and dimethyl sulfoxide

1995 ◽  
Vol 73 (4) ◽  
pp. 471-482 ◽  
Author(s):  
Craig Anderson ◽  
André L. Beauchamp
Keyword(s):  
Dimethyl Sulfoxide ◽  
1H Nmr ◽  
Room Temperature ◽  
Single Species ◽  
X Ray Diffraction ◽  
Chloro Complexes ◽  
X Ray ◽  
H Nmr ◽  
Nmr Study ◽  
Nmr Signals

The 1H NMR signals of the Ru(III) species present in solution are considerably broadened and shifted by paramagnetism, but they can be used to follow chloride displacement in the trans-[RuCl4Im2]− ion. This anion remains predominant for several hours at room temperature in D2O, but its signals are progressively replaced by those of a monoaqua [RuCl3(D2O)Im2] complex. Over a period of days, two new sets of peaks appear, corresponding to two isomers of [RuCl2(D2O)2Im2]+. The same behaviour is observed for the 1-methyl-and 4-methylimidazole analogues. These reactions can be driven backwards by addition of KCl, but [RuCl4Im2]− is not quantitatively regenerated in solution even for 6 M NaCl. Within several months, the [RuCl2(D2O)2Im2]+ isomers further aquate to a single species [RuCl(D2O)3Im2]2+. In CD3OD, displacement of the first chloride of [RuCl4Im2]− takes place faster, over several hours, but substitution stops at the [RuCl3(CD3OD)Im2] stage. In DMSO, substitution occurs very slowly. The [RuCl3(DMSO)Im2]:[RuCl4Im2]−mixture (1:2) obtained after 12 days starts to show very slow reduction to two Ru(II) species, one of which precipitates as yellow crystals. From X-ray diffraction work (monoclinic, P21/n, a = 9.951, b = 8.564, c = 10.527 Å, β = 92.95°, R = 0.033), the compound was identified as [RuCl2(DMSO-d6)2Im2], where the metal has a trans-trans-trans coordination and the DMSO ligands are S-bonded. Keywords: paramagnetic ruthenium anion, solvolysis, chloro complexes.

(-)-Armepavine: Gradient-Enhanced 2D NMR Study and X-Ray Crystal Structure Determination

1997 ◽  
Vol 62 (10) ◽  
pp. 1623-1630 ◽  
Author(s):  
Radek Marek ◽  
Jaromír Marek ◽  
Jiří Dostál ◽  
Jiří Slavík
Keyword(s):  
Crystal Structure ◽  
Nmr Spectroscopy ◽  
Structure Determination ◽  
Nmr Assignment ◽  
2D Nmr ◽  
X Ray Diffraction ◽  
2D Nmr Spectroscopy ◽  
X Ray ◽  
Nmr Study ◽  
Benzylisoquinoline Alkaloid

(-)-Armepavine, a benzylisoquinoline alkaloid isolated from Papaver caucasicum, was examined by gradient-enhanced 2D NMR spectroscopy and X-ray diffraction analysis. Unambiguous 1H, 13C, and 15N NMR assignment of the title alkaloid is reported.

Carbacylamidophosphates: Structure and Properties of Bis(N,N′,-morpholido)-[(N″-morpholido)-carboxamido] phosphate

1999 ◽  
Vol 54 (11) ◽  
pp. 1357-1359 ◽  
Author(s):  
Kateryna E Gubina ◽  
Vladimir A. Ovchynniko ◽  
Vladimir M Amirkhanov ◽  
Tatyana Yu. Sliva ◽  
Viktor V. Skopenko ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Hydrogen Bonds ◽  
Protonation Constant ◽  
Unit Cell ◽  
Potentiometric Studies ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Independent Molecules

The bis(N,N′-morpholido)-[(N″-morpholido)-carboxamido] phosphate: O(CH2CH2 )NC(O )-N(H)P(O)[N(CH2CH2 )O]2 [HL], has been prepared and characterized by means of IR, 31P and 1H NMR spectroscopy and X-ray diffraction (triclinic, a = 9.282(2), b = 9.308(2), c = 21.341(4) Å, α = 80.79(3)°, β = 80.92(3)° γ = 66.92(3)°, V = 1665.1(6) Å3, space group P1̄̄, Z = 4 and R = 0.0423, wR2 = 0.1303 for 6774 unique reflections used). The unit cell consists of two independent molecules connected by hydrogen bonds N-H...O=P into non-symmetric dimers. The compound behaves as a HL molecule with a protonation constant corresponding to the -C(O)N(H)P(O)- group of pK = 8.65 as determined by potentiometric studies.

scholarly journals 2D-Coordination polymer containing lead(II) in a hemidirected PbO4S3 environment formed by molecular breaking of the 1,3-oxathiolane ligand

2019 ◽  
Vol 74 (7-8) ◽  
pp. 547-551
Author(s):  
Zahra Mardani ◽  
Samira Akbari ◽  
Keyvan Moeini ◽  
Majid Darroudi ◽  
Cameron Carpenter-Warren ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Coordination Polymer ◽  
Hydrogen Bonds ◽  
Thiol Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Anionic Ligand ◽  
Ft Ir ◽  
Complexation Process

AbstractA new 1,3-oxathiolane-based ligand, 2-(1,3-oxathiolan-2-yl)pyridine, was prepared and its coordination to lead(II) was investigated. Experiments revealed a ligand-breaking reaction during the complexation process, which leads to the formation of a 2D-coordination polymer of lead(II), [Pb(μ3-HME)(μ-OAc)]n; H2ME: 2-mercaptoethanol. The compounds have been characterized by elemental analysis, FT-IR, 1H NMR spectroscopy and single-crystal X-ray diffraction. X-ray analysis revealed a 2D-coordination polymer extending via acetato bridges. The lead(II) center adopts a rare PbO4S3-distorted pentagonal bipyramidal geometry with a hemidirected arrangement. Upon coordination, the thiol group of the H2ME ligand is deprotonated to coordinate as an anionic ligand. The network extends in sheets in the crystallographic ab plane via Pb–S–Pb and Pb–O–Pb bridges, aided by O–H⋯O hydrogen bonds.

scholarly journals Zur Struktur von Tris(1,3-dimethyl-2-indolyl)-methan: Ein chiraler C3-Propeller aus der Trishetarylmethan-Reihe / The Structure of Tris(1,3-dim ethyl-2-indolyl)m ethane: a Chiral C3-Propeller in the Trishetarylmethane Series

1986 ◽  
Vol 41 (6) ◽  
pp. 762-767 ◽  
Author(s):  
Werner Massa ◽  
Thomas Kämpchen ◽  
Johann Müller ◽  
Ulf Pindur
Keyword(s):  
Nmr Spectroscopy ◽  
Model Compound ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Temperature Dependant

AbstractThe structure of tris(1,3-dim ethyl-2-indolyl)methane (1) as a model compound for C3-skeleton symmetric trishetaryl-methanes is elucidated by X-ray diffraction and temperature dependant 1H NMR spectroscopy. The results demonstrate, that 1 adopts a chiral C3-propeller conformation (P/M-helix) as well in crystal as in solution.

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