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.

An 1H NMR Study on the Cationic Motion in Solid tert-Butylammonium Chloride and Bromide

1991 ◽  
Vol 46 (3) ◽  
pp. 265-268 ◽  
Author(s):  
Hiroyuki Ishida ◽  
Syuichi Inada ◽  
Naomi Hayama ◽  
Daiyu Nakamura ◽  
Ryuichi Ikeda
Keyword(s):  
Relaxation Time ◽  
1H Nmr ◽  
Room Temperature ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
X Ray ◽  
Spin Lattice ◽  
H Nmr ◽  
Nmr Study

AbstractThe 1H spin-lattice relaxation time (T1) in solid (CD3)3CNH3Cl and (CD3)3CNH3Br was measured above room temperature and the motional parameters for the reorientation of the NH3+ groups were determined. The 1H NMR absorptions measured in the same temperature range for (CH3)3CNH3Cl and (CH3)3CNH3Br indicate the presence of superimposed several cationic motions commonly taking place in both compounds. From X-ray powder patterns taken at room temperature, the bromide was found to be isomorphous with the chloride

Phase Diagram of the Orientationally Order-disorder Binary System 2,2-dimethyl-1,3-propanediol / 2,2-dimethyl-1,3-diaminopropane, [(CH3)2 C(CH2OH)2]x [(CH3)2C(CH2NH2)2]1-x · A Thermodynamic, X-ray, and 1H-NMR study

1996 ◽  
Vol 51 (7) ◽  
pp. 871-881 ◽  
Author(s):  
Roman Strauss ◽  
Sigmar Braun ◽  
Shi-qi Dou ◽  
Hartmut Fuess ◽  
Alarich Weiss
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Binary System ◽  
Phase I ◽  
1H Nmr ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Constants ◽  
H Nmr

AbstractThe phase diagram of the binary system [2,2-dimethyl-1,3-propanediol]x (1) / [2,2-dimethyl-1,3- diaminopropane]1-x (2) was studied by X-ray diffraction and DTA/DSC, for (2) also by 1H-NMR. The system is miscible over the whole concentration range 0 ≤ x ≤ 1 in the liquid state and in the plastic solid state, phase I, just below the melting point. At lower temperatures the system is demixing, and at room temperature two plastic mixed crystals coexist. The plastic phases of (1), (2), and (l)x(2)1-x crystallize face centered cubic, Fm3m, Z = 4, the lattice constants decreasing linearely with increasing x, and the lattice constants are: (1) a(327K) = 880.3 pm , (2) a(243K) = 905.6 pm. By single crystal X-ray diffraction the structure of the ordered phase II of (1) was refined at room temperature, monoclinic, P21/n, Z = 4, a = 596.9 pm, b = 1090.2 pm, c = 1011.0 pm, β = 99.74°. The results are in good agreement with the literature. The phase transition temperatures (in Kelvin) are T1→m = 399.2, TMm→1 = 399.7, T11→1 = 316.2, T1→11 = 308.2 for (1); = 300.2, = 301.7, T11→1 = 228.7, T1→n = 194.2 for (2). Strong hysteresis is observed for the transition T1→11 in (2). In the mixed systems (1)x(2)1-x, 0 < x < 1, the disordered phases do not order even by quenching to liquid nitrogen temperature. High resolution 1 H-NMR measurements are reported for phase I of (2) as a function of temperature. The “liquid” 1H-NMR spectrum is present far below the thermodynamic phase transition temperature T11-1, overlapping the wide line unresolved powder spectrum of phase II.

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.

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.

scholarly journals Lactide polymerization with iron alkoxide complexes

2015 ◽  
Vol 93 (6) ◽  
pp. 594-601 ◽  
Author(s):  
Arek Keuchguerian ◽  
Berline Mougang-Soume ◽  
Frank Schaper ◽  
Davit Zargarian
Keyword(s):  
Single Crystal ◽  
Room Temperature ◽  
Side Reactions ◽  
X Ray Diffraction ◽  
Iron Cluster ◽  
X Ray ◽  
H Nmr ◽  
Exchange Product

This report presents the results of a study on the preparation of iron alkoxide complexes chelated by diiminopyridine ligands and their role in the room temperature polymerization of rac-lactide. Reaction of N,N′-(p-R-C6H4CH2)2-diiminopyridines (R = H (1), F (2)) with FeX2 (X = Cl, Br) yielded the homoleptic complexes [(1)2Fe][FeX4] or [(2)2Fe][FeX4], respectively. Treating the latter with Na[BPh4] afforded the anion exchange product [(2)2Fe][BPh4]2, which was characterized by 1H NMR and absorption spectroscopy, combustion analysis, and single crystal X-ray diffraction. Various attempts to grow crystals of [(1)2Fe][FeX4] and [(2)2Fe][FeX4] culminated in the isolation of single crystals of [(2)2Fe][Cl6Fe2O] that was characterized by X-ray diffraction. Attempted synthesis of well-defined, mononuclear alkoxide derivatives from [(1)2Fe]2+ or [(2)2Fe]2+ gave mostly intractable products, but in one case we obtained the crystallographically characterized sodium iron cluster Na4Fe2(OC6H4F)8(THF)2. An aryloxide derivative proved accessible by reaction of NaOC6H4F with the mono-ligand precursor LFeCl2 (L = N,N′-dimesityl-diiminopyridine), but characterization of LFe(OC6H4F)2 was limited to a single crystal X-ray diffraction analysis, owing to unsuccessful attempts at isolating pure samples. The difficulties encountered in the isolation of pure alkoxide derivatives prompted us to use in-situ generated LFe(OEt)2 for studying the polymerization of rac-lactide. This system was found to be moderately active at room temperature and with a slight preference for the formation of a heterotactic polymer (Pr = 0.54–0.65). Large polydispersities of 1.5–2.0 indicated the presence of transesterification side-reactions, which were confirmed by the presence of peaks with m/z = n 144 + M(EtOH) + M(Na+) and m/z = (n + 0.5) 144 + M(EtOH) + M(Na+) in MALDI-MS.

Structures of Energetic Acetylene Derivatives HC≡CCH2ONO2, (NO2)3CCH2C≡CCH2C(NO2)3 and Trinitroethane, (NO2)3CCH3

2013 ◽  
Vol 68 (5-6) ◽  
pp. 719-731 ◽  
Author(s):  
Thomas M. Klapötke ◽  
Burkhard Krumm ◽  
Richard Moll ◽  
Alexander Penger ◽  
Stefan M. Sproll ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Gas Phase ◽  
Quantum Chemical ◽  
Room Temperature ◽  
Molecular Structures ◽  
X Ray Diffraction ◽  
Polar Solvents ◽  
X Ray ◽  
Nmr Study ◽  
Acetylene Derivatives

The molecular structures and relative ratios of the two conformers (anti and gauche) of HCCCH2ONO2 detected in the gas phase at room temperature have been determined by electron diffraction. The results are discussed on the basis of quantum chemical calculations. The molecular structures of (NO2)3CCH2C≡CCH2C(NO2)3 and (NO2)3CCH3 have been determined by X-ray diffraction. A109Ag NMR study was performed for silver trinitromethanide Ag[C(NO2)3] in various polar solvents.

scholarly journals Trinodal Self-Penetrating Nets from Reactions of 1,4-Bis(alkoxy)-2,5-bis(3,2’:6’,3’’-terpyridin-4’-yl)benzene Ligands with Cobalt(II) Thiocyanate

Crystals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 529 ◽  
Author(s):  
Giacomo Manfroni ◽  
Alessandro Prescimone ◽  
Stuart R. Batten ◽  
Y. Maximilian Klein ◽  
Dariusz J. Gawryluk ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Crystal Growth ◽  
Single Crystal ◽  
Crystal Lattice ◽  
1H Nmr ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray

The tetratopic ligands 1,4-bis(2-ethylbutoxy)-2,5-bis(3,2’:6’,3’’-terpyridin-4’-yl)benzene (1) and 1,4-bis(3-methylbutoxy)-2,5-bis(3,2’:6’,3’’-terpyridin-4’-yl)benzene (2) have been prepared and characterized by 1H and 13C{1H} NMR, IR, and absorption spectroscopies and mass spectrometry. Reactions of 1 and 2 with cobalt(II) thiocyanate under conditions of crystal growth at room temperature result in the formation of [{Co(1)(NCS)2}·MeOH·3CHCl3]n and [{Co(2)(NCS)2}·0.8MeOH·1.8CHCl3]n. Single-crystal X-ray diffraction reveals that each crystal lattice consists of a trinodal self-penetrating (62.84)(64.82)(65.8)2 net. The nodes are defined by two independent cobalt centres and the centroids of two crystallographically independent ligands which are topologically equivalent.

Wideline 1H NMR Study on Hydrated Layered Sulfides K0.5(H2O)y[NbS2] and Na0.5(H2O)y[NbS2]

1977 ◽  
Vol 32 (9) ◽  
pp. 1033-1037 ◽  
Author(s):  
Anton Lerf ◽  
Paul Burkert ◽  
Jürgen O. Besenhard ◽  
Robert Schöllhorn
Keyword(s):  
1H Nmr ◽  
Nmr Spectra ◽  
Room Temperature ◽  
Interlayer Space ◽  
Water Molecules ◽  
Structural Scheme ◽  
H Nmr ◽  
Nmr Study

H NMR spectra of different hydration stages show that the water molecules in hydrated layered niobium sulfides A0.5(H2O)y[NbS2] are rather mobile at room temperature. A structural scheme of water arrangement in the interlayer space is proposed with the C2-axis of the H2O molecules parallel to the basal planes of the NbS2 layer units.

NMR Study of the Crystallization Kinetics of Cis-Poly(Isoprene)s

1973 ◽  
Vol 46 (1) ◽  
pp. 22-29 ◽  
Author(s):  
R. C. Hirst ◽  
H. Y. Chen
Keyword(s):  
Room Temperature ◽  
Curve Shape ◽  
X Ray Diffraction ◽  
Rigid Lattice ◽  
X Ray ◽  
Nmr Study ◽  
Accurate Comparison ◽  
Dilatometric Studies ◽  
Kinetics Of ◽  
Good Agreement

Abstract The satisfactory agreement between our NMR results and X-ray diffraction results for the crystallinity in stark rubber at room temperature lead us to conclude that the NMR rigid lattice fraction, PRL, may be taken as equal to the fractional crystallinity obtained by other methods. Similarly, the good agreement between the time dependence of PRL at low temperature and the theoretical curve shape strongly suggest that the NMR crystallinity method works well down to at least −25° C for natural rubber and synthetic cis-poly (isoprene). It would be desirable to compare carefully the NMR crystallinity found for rubber crystallized at −25° C with X-ray diffraction results, but we have been unable to find any such X-ray diffraction studies at −25° C. Maximum values of ΔV/V≅0.025 from dilatometric studies appear to imply somewhat smaller crystallinities than those found by NMR, but an accurate comparison is not possible without having X-ray diffraction densities at −25° C. While the present experiments were carried out on unfilled, unstretched, unvulcanized samples, the NMR crystallinity method is equally applicable to samples which are filled, stretched, and vulcanized. Naturally any additive or impurity containing hydrogen is a possible source of interference, but there should be no difficulty in correcting for such interferences.

scholarly journals Synthesis and molecular structure of perhalogenated rhenium-oxo corroles

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Abraham B. Alemayehu ◽  
Rune F. Einrem ◽  
Laura J. McCormick-McPherson ◽  
Nicholas S. Settineri ◽  
Abhik Ghosh
Keyword(s):  
Molecular Structure ◽  
Photodynamic Therapy ◽  
Single Crystal ◽  
Room Temperature ◽  
Structural Variations ◽  
X Ray ◽  
H Nmr ◽  
Elemental Chlorine ◽  
High Valent ◽  
Nmr Signals

AbstractAs part of our efforts to develop rhenium-oxo corroles as photosensitizers for oxygen sensing and photodynamic therapy, we investigated the potential β-perhalogenation of five ReO meso-tris(para-X-phenyl)corroles, Re[TpXPC](O) (X = CF3, H, F, CH3, and OCH3), with elemental chlorine and bromine. With Cl2, β-octachlorinated products Re[Cl8TpXPC](O) were rapidly obtained for X = CF3, H, and CH3, but X = OCH3 resulted in overchlorination on the meso-aryl groups. Full β-octabromination proved slower relative to Cu and Ir corroles, but the desired Re[Br8TpXPC](O) products were finally obtained for X = H and F after a week at room temperature. For X = CH3 and OCH3, these conditions led to undecabrominated products Re[Br11TpXPC](O). Compared to the β-unsubstituted starting materials, the β-octahalogenated products were found to exhibit sharp 1H NMR signals at room temperature, indicating that the aryl groups are locked in place by the β-halogens, and substantially redshifted Soret and Q bands. Single-crystal X-ray structures of Re[Cl8TpCF3PC](O), Re[Cl8TpCH3PC](O), and Re[Br8TpFPC](O) revealed mild saddling for one Cl8 structure and the Br8 structure. These structural variations, however, appear too insignificant to explain the slowness of the β-octabromination protocols, which seems best attributed to the deactivating influence of the high-valent Re center.

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