1H NMR study of paramagnetic rhenium(III) monomers with nitrogen heterocycles. Crystal structures of ReCl3L2(PPh3) complexes (L = pyridine, 3-picoline, and 1-methylimidazole)

1997 ◽  
Vol 75 (2) ◽  
pp. 220-231 ◽  
Author(s):  
Céline Pearson ◽  
André L. Beauchamp
Keyword(s):  
Crystal Structures ◽  
Paramagnetic Nmr ◽  
X Ray Diffraction ◽  
Heterocyclic Ligands ◽  
Conjugated Systems ◽  
H Nmr ◽  
Low Field ◽  
Metal Atoms ◽  
Nmr Study ◽  
Nmr Signals

Rhenium(III) monomers of the type ReCl3Ln(PPh3)3−n, where n = 1,2, and 3, were prepared for simple nitrogen heterocyclic ligands L and characterized mainly by 1H NMR and IR spectroscopies. Most of the 1H NMR signals of these paramagnetic compounds were assigned by using methylated pyridines. A mer-cis octahedral geometry slightly distorted by triphenylphosphine was determined by X-ray diffraction for three ReCl3L2(PPh3) complexes: L = pyridine, triclinic, [Formula: see text], a = 11.379, b = 13.532, c = 18.160 Ǻ, α = 80.16°, β = 89.57, γ = 86.27°, Z = 4, R = 0.076; L = 3-picoline, triclinic, [Formula: see text], a = 10.557, b = 12.580, c = 13.153 Ǻ, α = 66.80°, β = 67.46°, γ = 75.89°, Z = 2, R = 0.021; L = 1-methylimidazole, monoclinic, P21/c, α = 15.437, b = 9.436, c = 18.607 Ǻ, β = 92.23°, Z = 4, R = 0.046. The same structure was deduced from 1H NMR data for these compounds in solution, whereas the other types of complexes were found to exist as the mer,trans-ReCl3L(PPh3)2 and mer-ReCl3L3 isomers. In contrast with these complexes, which contain the mer-ReCl3 core, the starting material ReCl3(benzil)(PPh3) is found to be the fac isomer in solution. The typical low-field shifted pattern of 1H NMR signals for PPh3 is not greatly perturbed by changes in the number or arrangement of the remaining ligands in the coordination sphere, but the signals for protons on conjugated systems directly bonded to the metal atoms are much more affected by the unpaired electrons. Keywords: paramagnetic NMR, crystal structures, rhenium(III) complexes, imidazole, pyridine, triphenylphoshine.

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.

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.

scholarly journals Syntheses and crystal structures of 2-(p-tolyl)-1H-perimidine hemihydrate and 1-methyl-2-(p-tolyl)-1H-perimidine

2022 ◽  
Vol 78 (2) ◽  
Author(s):  
Paulina Kalle ◽  
Sergei V. Tatarin ◽  
Marina A. Kiseleva ◽  
Alexander Yu. Zakharov ◽  
Daniil E. Smirnov ◽  
...  
Keyword(s):  
Water Molecule ◽  
Crystal Structures ◽  
Crystal Packing ◽  
Rotation Axis ◽  
Point Group ◽  
Group Symmetry ◽  
X Ray Diffraction ◽  
Hydrogen Atoms ◽  
H Nmr ◽  
Rotation Axes

The title compounds, 2-(4-methylphenyl)-1H-perimidine hemihydrate (1, C18H14N2·0.5H2O) and 1-methyl-2-(4-methylphenyl)-1H-perimidine (2, C19H16N2), were prepared and characterized by 1H NMR and single-crystal X-ray diffraction. The organic molecule of the hemihydrate lies on a twofold rotation axis while the water molecule lies on the intersection of three twofold rotation axes (point group symmetry 222). As a consequence, the hydrogen atoms that are part of the N—H group and the water molecule as well as the CH3 group of the p-tolyl ring are disordered over two positions. In compound 1, the perimidine and the 2-aryl rings are slightly twisted while its N-methylated derivative 2 has a more distorted conformation because of the steric repulsion between the N-methyl group and the 2-aryl ring. In the crystal structures, molecules of perimidine 2 are held together only by C—H...π contacts while the parent perimidine 1 does not exhibit this type of interaction. Its crystal packing is established by intermolecular N—H...O hydrogen bonds with the solvent water molecules and additionally stabilized by π–π stacking.

NMR-Spektroskopie an paramagnetischen Komplexen, XIX 13C-und 1H-NMR-Zugang zu gewinkelten Titanocenen/NMR Spectroscopy on Paramagnetic Complexes, XIX 13C and 1H NMR Access to Bent Titanocenes

1978 ◽  
Vol 33 (11) ◽  
pp. 1274-1277 ◽  
Author(s):  
Frank H. Köhler ◽  
Daniel Cozak
Keyword(s):  
Gas Phase ◽  
1H Nmr ◽  
High Field ◽  
Nmr Spectra ◽  
Membered Ring ◽  
Proton Exchange ◽  
Paramagnetic Nmr ◽  
Ligand Dissociation ◽  
H Nmr ◽  
Low Field

Abstract From [(RC5H4)2TiCl]2, R = H (1), CH3 (2) and C2H5 (3), (C5H5)2TiBH4 (4) and (C5H5)2Ti(CH3CN)Cl (5) the first paramagnetic 13C and 1H NMR spectra in the series of bent titanocenes have been obtained. Broad signals shifted to low field originate from the cyclopentadienyl protons while the corresponding 13C signals appear at high field relative to a diamagnetic reference. This is ascribed to π-polarisation which dominates the transfer of unpaired electrons onto the five-membered ring while σ-polarisation delocalizes them onto other ligands. The NMR shifts indicate that titanocene halides are antiferromagnetically coupled in solution, the extent depending on the solvent and on five-membered ring substituents. In the gas phase only monomers are found by mass spectroscopy. Paramagnetic NMR further reveals proton exchange in 4 and ligand dissociation in 5.

Darstellung, 11B-, 13C-, 1H-NMR-Spektren und Schwingungsspektren von 1,2-Xylylen-pentahydro-closo-hexaborat,cis-[B6H5(CH2)2C6H4]- , sowie Kristallstrukturen von cis-[P(C6H5)4][B6H5(CH2)2C6H4] und cis-[(n-C4H9)4N][B6H5(CH2)2C6H4] / Preparation, 11B, 13C, 1H NMR Spectra and Vibrational Spectra of 1,2-Xylylene-pentahydro-closo-hexaborate, cis-[B6H5(CH2)2C6H4]-, and the Crystal Structures of cis-[P(C6H5)4][B6H5(CH2)2C6H4] and cis-[(n-C4H9)4N ][B6H5(CH2)2C6H4]

1996 ◽  
Vol 51 (5) ◽  
pp. 691-697 ◽  
Author(s):  
W. Lübbe ◽  
W. Preetz
Keyword(s):  
Crystal Structures ◽  
1H Nmr ◽  
Nmr Spectra ◽  
Exchange Chromatography ◽  
Monoclinic Space Group ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Diethylaminoethyl Cellulose

By reaction of [B6H6]2- with ω,ω′-dibromo-o-xylene in acetonitrile the 1,2-xylylenepentahydro-closo-hexaborat, cis-[B6H5(CH2)2C6H4]- , is formed. The new ansa compound has been separated from excess [B6H6]2- and other reaction products by ion exchange chromatography on diethylaminoethyl cellulose. The crystal structures of cis-[P(C6H5)4][B6H5(CH2)2C6H4] (I) and as-[(n-C4H9)4N][B6H5(CH2)2C6H4] (II) have been determined by single crystal X-ray diffraction analysis: I is monoclinic, space group P 21/n with a = 13.715(5), b = 11.118(1) and c = 19.702(2) Å, β = 103.47(2)°; II is orthorhombic with a = 10.204(7), b = 13.352(4) and c = 20.824(8) Å. The 11B NMR spectrum confirms the structure with a hetero disubstituted octahedral B6 cage with local C2v symmetry. The 13C and 1H NMR spectra have been assigned in term of such a configuration. The IR and Raman spectra exhibit characteristic CH, BH, BC, B6 and arene vibrations.

Komplexe eines vierzehngliedrigen Tetraazadibenzo-Makrocyclus. Strukturen des freien und zweifach protonierten Liganden und seiner Nickel(II)-, Kupfer(II)-, Zink(II)- und Palladium(II)-Komplexe / Complexes of a 14-Membered N4 Dibenzo Macrocycle. Crystal Structures of the Free and Diprotonated Ligand and of its Nickel(II), Copper(II), Zink(II) and Palladium (II) Complexes

1996 ◽  
Vol 51 (6) ◽  
pp. 869-878 ◽  
Author(s):  
Ralf Feldhaus ◽  
Jens Köppe ◽  
Rainer Mattes
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Free Ligand ◽  
X Ray Diffraction ◽  
Intermolecular Hydrogen Bonds ◽  
Structural Characterisation ◽  
Metal Atoms ◽  
Intramolecular Hydrogen ◽  
Nitrogen Bond ◽  
Macrocyclic Cavity

Abstract The synthesis and structural characterisation of complexes of the 14-membered macrocyclic trans-N4 dibenzo ligand 5,6,7,8,9,14.15,16,17,18-decahydrodibenzo[e,l][1,4, 8,11]-tetraazacyclotetradecine (L2) is described. The crystal structures of six compounds were determined by single crystal X-ray diffraction. The free ligand L2 has a saddle-shaped structure with short intramolecular hydrogen bonds. The N-N distances are 289 pm. The diprotonated species [H2L2]2+ has a different conformation due to intra- and intermolecular hydrogen bonds. The ligand is folded along an N-N axis in c/s-[Ni(L2)(H2O)2]2+, but displays a saddleshaped structure in the Cu(II), Zn(II) and Pd(II) complexes with a more or less planar arrangement of the four N donor atoms. The metal atoms are incorporated within the macrocyclic cavity in [Cu(L2)(CF3SO3)]+ and [Pd(L2)]2+. The metal-to-nitrogen bond lengths herein are rather small. Zn(II) is five-coordinate in [Zn(L2)(Cl)]+. The coordination polyhedron is intermediate between a trigonal bipyramid and a square pyramid. In all complexes the metalto- ligand distances originating at the nitrogen atoms in β-position (with respect to the aromatic ring) are significantly shorter then the donor bonds of the ‘anilinic’ N atoms

Tetraphenylphosphonium-hexachlorodizinkat und -hexachlorodicadmat, (PPh4)2Zn2Cl6 und (PPh4)2Cd2Cl6 / Tetraphenylphosphonium Hexachlorodizincate and Hexachlorodicadmate, (PPh4)2Zn2Cl6 and (PPh4)2Cd2Cl6

1989 ◽  
Vol 44 (9) ◽  
pp. 1037-1040 ◽  
Author(s):  
Jörg Hubertus Wilhelm ◽  
Ulrich Müller
Keyword(s):  
Crystal Structures ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Metal Atoms

The title compounds were obtained by the reactions of PPh4Cl, HCl and ZnS or CdS in CH2Cl2. Their crystal structures were determined by X-ray diffraction. (PPh4)2Zn2Cl6: a = 973.6(1). b = 982.6(2), c = 1296.7(3) pm, α = 107.93(2), β = 94.50(2), γ = 100.91(2)°, R = 0.036 for 2237 unique observed reflexions. (PPh4)2Cd2Cl6: a = 977.1(2), b = 997.5(3). c = 1306.6(3) pm. α = 108.81(2), β = 94.18(2), γ = 100.24(2)°, R = 0.050 for 1921 reflexions. Both compounds are isotypic in the triclinic space group P1̄ and consist of PPh4+ ions and dimeric, centrosymmetric M2Cl6- ions in which the tetrahedrally coordinated metal atoms are linked via chloro bridges.

scholarly journals Crystallographic and NMR Investigation of Ergometrine and Methylergometrine, Two Alkaloids from Claviceps Purpurea

Molecules ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 331 ◽  
Author(s):  
Fiorella Meneghetti ◽  
Patrizia Ferraboschi ◽  
Paride Grisenti ◽  
Shahrzad Reza Elahi ◽  
Matteo Mori ◽  
...  
Keyword(s):  
Intermolecular Interactions ◽  
15N Nmr ◽  
X Ray Diffraction ◽  
Nmr Study ◽  
Complete Assignment ◽  
Long Time ◽  
Definition Of ◽  
And Control ◽  
Nmr Signals ◽  
Conclusive Data

Ergometrine and methylergometrine are two alkaloids that are used as maleate salts for the prevention and control of postpartum hemorrhage. Although the two molecules have been known for a long time, few and discordant crystallographic and NMR spectroscopic data are available in the literature. With the aim of providing more conclusive data, we performed a careful NMR study for the complete assignment of the 1H, 13C, and 15N NMR signals of ergometrine, methylergometrine, and their maleate salts. This information allowed for a better definition of their conformational equilibria. In addition, the stereochemistry and the intermolecular interactions in the solid state of the two maleate salts were deeply investigated by means of single-crystal X-ray diffraction, showing the capability of these derivatives to act as both hydrogen-bond donors and acceptors, and evidencing a correlation between the number of intermolecular interactions and their different solubility.

Synthesis and Crystal Structures of New 1,4-Disubstituted 1,2,4-Triazoline-5-thiones

2014 ◽  
Vol 69 (9-10) ◽  
pp. 950-964 ◽  
Author(s):  
Gerhard Laus ◽  
Volker Kahlenberg ◽  
Klaus Wurst ◽  
Herwig Schottenberger
Keyword(s):  
Solid State ◽  
Crystal Structures ◽  
Significant Contribution ◽  
Chemical Shifts ◽  
Resonance Structure ◽  
X Ray Diffraction ◽  
Reference Compound ◽  
Intermolecular Hydrogen Bonds ◽  
X Ray ◽  
H Nmr

AbstractIntroduction of sulfur into the 5-position of 1,4-disubstituted quaternary 1,2,4-triazolium salts (1-9; Cl, Br, I, BF4, PF6, CH3OSO3 were used as anions) by two methods was investigated. The syntheses of nine 1,4-disubstituted 1,2,4-triazoline-5-thiones 10-18 are reported (1, 10: R1 = CH3, R2 = CH3; 2, 11: R1 = NH2, R2 = CH3; 3, 12: R1 = NH2, R2 = CH(CH3)2; 4, 13: R1 = N(CH3)2, R2 = CH3; 5, 14: R1 = N(CH3)2, R2 = CH(CH3)2; 6, 15: R1 = CH3, R2 = NH2; 7, 16: R1 = OCH2Ph, R2 = CH3; 8, 17: R1 = OCH2Ph, R2 = CH2CH3; 9, 18: R1 = CH3, R2 = CH2Ph). Compounds 11-17 represent 1-amino, 4-amino, 4-dimethylamino, and 4-benzyloxy-1,2,4-triazoline-5- thiones, whereas 10 served as a reference compound. Thione 18 was identified as an unexpected by-product in the synthesis of 16 and was also prepared independently. Thermolysis of 10 in air gave 1,4-dimethyl-1,2,4-triazolium hydrogensulfate. Crystal structures of eight 1,4-disubstituted 1,2,4- triazoline-5-thiones were determined by single-crystal X-ray diffraction. Intermolecular hydrogen bonds (C-H···S, C-H···N, N-H···N, N-H···S) were observed in the solid state. The solvent-dependent 1H NMR chemical shifts of signals of 10 and 13 were satisfactorily correlated with the Kamlet- Abboud-Taft π* and b parameters in ten solvents. From the lack of correlation with the a parameter and from the C=S bond length (average 1.67 Å) a significant contribution of a mesoionic imidazolium-2-thiolate resonance structure seems unlikely

Synthesis, crystal structures and luminescence properties of seven mononuclear zinc(II), cadmium(II), cobalt(II) and nickel(II) complexes with 5-(4-methylphenyl)-3-(pyridin-2-yl)-1H-1,2,4-triazole

2017 ◽  
Vol 73 (5) ◽  
pp. 382-392 ◽  
Author(s):  
Feng-Yi Liu ◽  
Dong-Mei Zhou ◽  
Xiao-Lan Zhao ◽  
Jun-Feng Kou
Keyword(s):  
Transition Metal ◽  
Crystal Structures ◽  
Metal Binding ◽  
Three Dimensional ◽  
Supramolecular Structures ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
Metal Atoms ◽  
Wide Range ◽  
Transition Metal Salts

Due to their versatile coordination modes and metal-binding conformations, triazolyl ligands can provide a wide range of possibilities for the construction of supramolecular structures. Seven mononuclear transition metal complexes with different structural forms, namely aquabis[3-(4-methylphenyl)-5-(pyridin-2-yl)-1H-1,2,4-triazolato-κ2 N 1,N 5]zinc(II), [Zn(C14H11N4)2(H2O)], (I), bis[5-(4-methylphenyl)-3-(pyridin-2-yl)-1H-1,2,4-triazole-κ2 N 3,N 4]bis(nitrato-κO)zinc(II), [Zn(NO3)2(C14H12N4)2], (II), bis(methanol-κO)bis[3-(4-methylphenyl)-5-(pyridin-2-yl)-1H-1,2,4-triazolato-κ2 N 1,N 5]zinc(II), [Zn(C14H11N4)2(CH4O)2], (III), diiodidobis[5-(4-methylphenyl)-3-(pyridin-2-yl)-1H-1,2,4-triazole-κ2 N 3,N 4]cadmium(II), [CdI2(C14H12N4)2], (IV), bis[5-(4-methylphenyl)-3-(pyridin-2-yl)-1H-1,2,4-triazole-κ2 N 3,N 4]bis(nitrato-κO)cadmium(II), [Cd(NO3)2(C14H12N4)2], (V), aquabis[3-(4-methylphenyl)-5-(pyridin-2-yl)-1H-1,2,4-triazolato-κ2 N 1,N 5]cobalt(II), [Co(C14H11N4)2(H2O)], (VI), and diaquabis[3-(4-methylphenyl)-5-(pyridin-2-yl)-1H-1,2,4-triazolato-κ2 N 1,N 5]nickel(II), [Ni(C14H11N4)2(H2O)2], (VII), have been prepared by the reaction of transition metal salts (ZnII, CdII, CoII and NiII) with 3-(4-methylphenyl)-5-(pyridin-2-yl)-1H-1,2,4-triazole (pymphtzH) under either ambient or hydrothermal conditions. These compounds have been characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. All the complexes form three-dimensional supramolecular structures through hydrogen bonds or through π–π stacking interactions between the centroids of the pyridyl or arene rings. The pymphtzH and pymphtz− entities act as bidentate coordinating ligands in each structure. Moreover, all the pyridyl N atoms are coordinated to metal atoms (Zn, Cd, Co or Ni). The N atom in the 4-position of the triazole group is coordinated to the Zn and Cd atoms in the crystal structures of (II), (IV) and (V), while the N atom in the 1-position of the triazolate group is coordinated to the Zn, Co and Ni atoms in (I), (III), (VI) and (VII).

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