Multinuclear NMR spectra of [Pt(L)Cl3]− (L = pyridine derivatives) complexes and crystal structure of trans-Pt(2,6-di(hydroxymethyl)pyridine)2Cl2•2H2O

1996 ◽  
Vol 74 (11) ◽  
pp. 2121-2130 ◽  
Author(s):  
Fernande D. , ◽  
Corinne Bensimon ◽  
André L. Beauchamp
Keyword(s):  
Crystal Structure ◽  
Pyridine Ring ◽  
Chemical Shifts ◽  
Bond Distance ◽  
Coupling Constants ◽  
Mirror Plane ◽  
Pyridine Derivative ◽  
Pyridine Derivatives ◽  
Pyridine Ligand ◽  
Twofold Axis

Complexes of the type [Pt(L)Cl3]− (L = pyridine derivative) were synthesized and studied by 13C and 195Pt NMR spectroscopies. The 195Pt signals were observed between −1720 and −1897 ppm. No correlation between the δ(Pt) and the pKa of the protonated pyridine derivatives was found. The chemical shifts vary with the substituents on the pyridine ligand. Compounds with substituents in ortho positions were observed at lower fields, except for complexes containing hydroxy or amine groups. The latter compounds were observed at higher fields, close to the signals of the Pt-unsubstituted pyridine compound. These results were explained in terms of the solvent effect. The chemical shifts δ(C) and the coupling constants J(13C–195Pt) were measured and the results interpreted with a view of obtaining information on the nature of the Pt—N bond. The possibility of π-bonding between platinum and the pyridine ligand is examined. The conformation of the pyridine ring in relation to the platinum plane and the energies of the rotation barriers around the Pt—N bond in these types of platinum(II) complexes are briefly discussed. The crystal structure of trans-Pt(2,6-(HOCH2)2py)2Cl2•2H2O was determined by X-ray diffraction. The compound is monoclinic, C2/m, a = 7.022(6), b = 15.646(13), c = 8.344(10) Å, β = 93.35(8)°, Z = 2, R = 0.037. The platinum atom is located at the junction of the twofold axis and the mirror plane, the N atoms and the para-C atom of the pyridine ring are situated on the twofold axis, and the chloride ligands are on the mirror plane. The compound crystallizes with molecules of water, which are H-bonded to the hydroxy groups. The Pt—Cl bond distance is 2.306(2) Å, and that of the Pt—N bond is 2.041 (6) Å. The dihedral angle between the platinum and the pyridine planes is 79.8°. Key words: platinum, pyridine derivatives, NMR, crystal structure.

scholarly journals Crystal structure of 2,6-bis(3-hydroxy-3-methylbut-1-yn-1-yl)pyridine monohydrate

2020 ◽  
Vol 76 (11) ◽  
pp. 1737-1740
Author(s):  
Take-aki Koizumi ◽  
Toshikazu Takata
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Water Molecule ◽  
Pyridine Ring ◽  
Pyridine Molecule ◽  
Pyridine Derivative ◽  
Oh Groups

In the title pyridine derivative, C15H17NO2·H2O, the two OH groups are oriented in directions opposite to each other with respect to the plane of the pyridine ring. In the crystal, hydrogen bonds between the pyridine molecule and the water molecule, viz. Ohydroxy—H...Owater, Ohydroxy—H...Ohydroxy, Owater—H...Ohydroxy and Owater—H···Npyridine, result in the formation of a ribbon-like structure running along [011].

Crystal structure and electronic spectrum for Bis(O-ethylxanthato)pyridinezinc(II)

1976 ◽  
Vol 29 (4) ◽  
pp. 731 ◽  
Author(s):  
CL Raston ◽  
AH White ◽  
G Winter
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Electronic Spectrum ◽  
Title Compound ◽  
Pyridine Ring ◽  
Zinc Atom ◽  
Full Matrix ◽  
X Ray ◽  
Twofold Axis ◽  
Axis Passing

The crystal structure of the title compound [Zn(C5H5N)(CS2OEt)2] has been determined from X-ray diffractometer data at 295 K and refined by full-matrix least squares to a residual of 0.061 for 1100 'observed' reflections. Crystals are monoclinic A2/a, a = 14.001(5), b = 8.911(2), c = 13.731(6) � ,β = 104.80(3)�, Z = 4. The molecule lies on a twofold axis passing through the N-coordinated pyridine ring. The zinc atom is coordinated by the pyridine [Zn-N, 2.03(l) �] and a pair of symmetry related asymmetric ethylxanthate chelates [Zn-S, 2.748(3), 2.294(3)&.The electronic spectrum of the complex has been studied in a variety of basic solvents and the spectra rationalized in terms of the observed structure.

scholarly journals Crystal structure of a new 2,6-bis(imino)pyridine derivative: (1E,1′E)-1,1′-(pyridine-2,6-diyl)bis[N-(4-chlorophenyl)ethan-1-imine]

2019 ◽  
Vol 75 (2) ◽  
pp. 115-118 ◽  
Author(s):  
Rajagopal Rajesh ◽  
E. S. Sella ◽  
Olivier Blacque ◽  
Kunjanpillai Rajesh
Keyword(s):  
Crystal Structure ◽  
Title Compound ◽  
Pyridine Ring ◽  
Pyridine Derivative ◽  
Asymmetric Unit ◽  
Double Bonds ◽  
Π Interactions ◽  
Compound C ◽  
Independent Molecules

The asymmetric unit of the title compound, C21H17Cl2N3, contains two crystallographically independent molecules (AandB). Both molecules haveEconfigurations for both imine double bonds with regard to the aryl and pyridine groups. The conformations of the two molecules differ with the 4-chlorophenyl rings being inclined to the central pyridine ring by 77.64 (6) and 86.18 (6)° in moleculeA, and 80.02 (5) and 43.41 (6)° in moleculeB. In the crystal, molecules are linked by a number of C—H...π interactions, forming layers parallel to thebcplane.

scholarly journals The Novel Monocomponent FAD-dependent Monooxygenase HpaM Catalyzes the 2-Decarboxylative Hydroxylation of 5-Hydroxypicolinic Acid inAlcaligenes faecalisJQ135

2017 ◽  
Author(s):  
Jiguo Qiu ◽  
Bin Liu ◽  
Lingling Zhao ◽  
Yanting Zhang ◽  
Dan Cheng ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Microbial Degradation ◽  
Pyridine Ring ◽  
Degradation Process ◽  
Alcaligenes Faecalis ◽  
Pyridine Derivative ◽  
Pyridine Derivatives ◽  
Monooxygenase Activity ◽  
E Coli ◽  
Transformation Mechanisms

Abstract5-hydroxypicolinic acid (5HPA) is a natural pyridine derivative that can be microbially degraded. However, the physiological, biochemical, and genetic foundation of the microbial catabolism of 5HPA remains unknown. In this study, a gene clusterhpa(which is involved in degradation of 5HPA inAlcaligenes faecalisJQ135) was cloned and HpaM was identified as a novel monocomponent FAD-dependent monooxygenase. HpaM shared a sequence only 31% similarity with the most related protein 6-hydroxynicotinate 3-monooxygenase (NicC) ofPseudomonas putidaKT2440.hpaMwas heterologously expressed inE. coliBL21(DE3), and the recombinant HpaM was purified via Ni-affinity chromatography. HpaM catalyzed the 2-decarboxylative hydroxylation of 5-HPA, thus generating 2,5-dihydroxypyridine (2,5-DPH). Monooxygenase activity was only detected in the presence of FAD and NADH, but not of FMN and NADPH. The apparentKmvalues of HpaM toward 5HPA and NADH were 45.4 μ and 37.8 μ, respectively. Results of gene deletion and complementation showed thathpaMwas essential for 5HPA degradation inAlcaligenes faecalisJQ135.ImportancePyridine derivatives are ubiquitous in nature and important chemical materials that are currently widely used in agriculture, pharmaceutical, and chemical industries. Thus, the microbial degradation and transformation mechanisms of pyridine derivatives received considerable attention. Decarboxylative hydroxylation was an important degradation process in pyridine derivatives, and previously reported decarboxylative hydroxylations happened in the C3 of the pyridine ring. In this study, we cloned the gene clusterhpa, which is responsible for 5HPA degradation inAlcaligenes faecalisJQ135, thus identifying a novel monocomponent FAD-dependent monooxygenase HpaM. Unlike 3-decarboxylative monooxygenases, HpaM catalyzed decarboxylative hydroxylation in the C2 of the pyridine ring in 5-hydroxypicolinic acid. These findings deepen our understanding of the molecular mechanism of microbial degradation of pyridine derivatives. Furthermore, HpaM offers potential for applications to transform useful pyridine derivatives.

scholarly journals Bis(acetylacetonato-κ2O,O′)(pyridine-κN)(thiocyanato-κN)manganese(III): a redetermination using data from a single crystal

2013 ◽  
Vol 69 (12) ◽  
pp. m657-m657
Author(s):  
Stefan Suckert ◽  
Inke Jess ◽  
Christian Näther
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Structure Determination ◽  
Title Compound ◽  
Complex Molecule ◽  
Mirror Plane ◽  
Asymmetric Unit ◽  
Pyridine Ligand ◽  
Thiocyanate Anion ◽  
Using Data

In the crystal structure of the title compound, [Mn(C5H7O2)2(NCS)(C5H5N)], the Mn3+cation is coordinated by two acetylacetonate anions, one terminal thiocyanate anion and one pyridine ligand within a slightly distorted octahedron. The asymmetric unit consists of half a complex molecule with the Mn3+cation, the thiocyanate anion and the pyridine ligand located on a mirror plane. The acetylacetonate anion is in a general position. The title compound was previously described [Stultset al.(1975).Inorg. Chem.14, 722–730] but could only be obtained as a powder. Suitable crystals have now been obtained for a high-precision single-crystal structure determination.

Synthesis, Conformational Analysis and Crystal Structure of New Thioxo, Oxo, Seleno Diastereomeric Cyclophosphamides Containing 1,3,2-dioxaphosphorinane

2019 ◽  
Vol 23 (2) ◽  
pp. 205-213
Author(s):  
Dorra Kanzari-Mnallah ◽  
Med L. Efrit ◽  
Jiří Pavlíček ◽  
Frédéric Vellieux ◽  
Habib Boughzala ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Density Functional ◽  
Chemical Shifts ◽  
Structural Determination ◽  
Conformational Study ◽  
Functional Theory ◽  
One Step ◽  
High Resolution Mass Spectroscopy ◽  
Resolution Mass

Thioxo, Oxo and Seleno diastereomeric cyclophosphamides containing 1,3,2- dioxaphosphorinane are prepared by a one-step chemical reaction. Their structural determination is carried out by means of Nuclear Magnetic Resonance NMR (31P, 1 H, 13C) and High-Resolution Mass Spectroscopy (HRMS). The conformational study of diastereomeric products is described. Density Functional Theory (DFT) calculations allowed the identification of preferred conformations. Experimental and calculated 31P, 13C, 1H NMR chemical shifts are compared. The molecular structure of the 2-Benzylamino-5-methyl-5- propyl-2-oxo-1,3,2-dioxaphosphorinane (3d) has been determined by means of crystal Xray diffraction methods.

Carbon-13 and nitrogen-14 NMR spectra of 1-(substituted phenyl)pyridinium salts

1980 ◽  
Vol 45 (10) ◽  
pp. 2766-2771 ◽  
Author(s):  
Antonín Lyčka
Keyword(s):  
Heavy Water ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Pyridinium Salts ◽  
Nmr Signals ◽  
C Nmr

The 13C and 14N NMR spectra of 1M solutions of 1-(substituted phenyl)pyridinium salts (4-CH3, 4-OCH3, H, 4-Cl, 4-Br, 4-I, 3-NO2, 4-NO2, 2,4-(NO2)2 (the 13C NMR only)) have been measured in heavy water at 30 °C. The 13C and 14N chemical shifts, the 1J(CH) coupling constants, some 3J(CH) coupling constants, and values of half-widths Δ 1/2 of the 14N NMR signals are given. The 13C chemical shifts of C(4) correlate with the σ0 constants (δC(4) = (1.79 ± 0.097) σ0 + (147.67 ± 0.041)), whereas no correlation of the nitrogen chemical shifts with the σ constants has been found. The half-widths Δ 1/2 correlate with the σ0 constants (Δ 1/2 = (76.2 ± 4.9) σ0 + (106.4 ± 2.2)) except for 1-phenylpyridinium chloride.

Gradient-Enhanced Inverse-Detected NMR Techniquesfor Determination of 1H-15N Coupling Constants in 2,2-Dimethylpenta-3,4-dienal Derivatives

1997 ◽  
Vol 62 (11) ◽  
pp. 1747-1753 ◽  
Author(s):  
Radek Marek
Keyword(s):  
Double Bond ◽  
Chemical Shifts ◽  
Multiple Bond ◽  
Coupling Constants ◽  
Single Quantum ◽  
Nmr Techniques ◽  
Phase Sensitive ◽  
Heteronuclear Coupling

Determination of 15N chemical shifts and heteronuclear coupling constants of substituted 2,2-dimethylpenta-3,4-dienal hydrazones is presented. The chemical shifts were determined by gradient-enhanced inverse-detected NMR techniques and 1H-15N coupling constants were extracted from phase-sensitive gradient-enhanced single-quantum multiple bond correlation experiments. Stereospecific behaviour of the coupling constants 2J(1H,15N) and 1J(1H,13C) has been used to determine the configuration on a C=N double bond. The above-mentioned compounds exist predominantly as E isomers in deuteriochloroform.

1H, 13C and 15N NMR Spectra of Coupling Products of Benzenediazonium Salts with Aliphatic Nitro Compounds and Study of Their E/Z Isomerism

1996 ◽  
Vol 61 (4) ◽  
pp. 589-596 ◽  
Author(s):  
Antonín Lyčka
Keyword(s):  
Dimethyl Sulfoxide ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Nitro Compounds ◽  
Coupling Constants ◽  
15N Nmr ◽  
Geometrical Isomers ◽  
Sodium Salts ◽  
Aliphatic Nitro Compounds ◽  
Tautomeric Forms

The 1H, 13C and 15N NMR spectra have been measured of coupling products of benzenediazonium salts with nitromethane, nitroethane, 1-nitropropane, 2-nitroethanol and of their sodium salts, and the chemical shifts have been unambiguously assigned. The coupling products have been found to exist only in their hydrazone tautomeric forms. Stereospecific behaviour of the coupling constants 2J(15N,1H) and 2J(15N,13C) in the 15N isotopomers and NOESY have been used to differentiate between the E and Z geometrical isomers. The above-mentioned compounds exist as Z isomers in deuteriochloroform and predominantly (>95%) as E isomers in dimethyl sulfoxide, while the sodium salts are present only as E isomers in dimethyl sulfoxide.

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