Synthesis and spectroscopic studies of cobalt(III) complexes with 5-methyl-3-formylpyrazole-N(4)-diethylthiosemicarbazone (HMPzNEt2): X-ray crystallography of [Co(MPzNEt2)2]ClO4·2H2O (I) and [Co(MPzNEt2)2]BF4·2H2O (II)

The preparation and properties of the thioether–pyridazine macrocycle (L4; C16H20S6N4) containing two pyridazine subunits, and its Cu(II), Cu(II)Cu(I), and Cu(I) complexes are described. The ligand is characterized by 1H nuclear magnetic resonance and mass spectrometry, and the complexes by infrared, eleetronic spectra, and magnetism, and in some cases by X-ray crystallography. The complex [Cu2(L4)Cl4]x, (1) crystallized in the triclinic system, space group [Formula: see text] with a = 8.6204(8) Å, b = 9.850(1) Å, c = 8.348(1) Å, α = 111.46(1)°, β = 102.50(1)°, γ = 71.818(9)°, V = 622.6(1) Å3, and Z = 1 (R = 0.043, Rw = 0.042 for 1312 reflections). Two monodentate pyridazine rings in the same ligand bind to one trans square-planar copper centre (CuN2Cl2) with two sulfurs from each ligand binding to another trans square-planar copper centre (CuS2Cl2) to form a polynuclear chain. The complex [Cu(L4)Cl2] (3) crystallized in the triclinic system, space group [Formula: see text] with a = 11.001(1) Å, b = 12.888(2) Å, c = 8.704(1) Å, α = 102.89(1)°, β = 103.36(1)°,γ = 75.84(1)°, V = 1145.8(3) Å3 and Z = 2 (R = 0.056, Rw = 0.044 for 2059 reflections). A trans square-planar structure (CuN2Cl2) exists for 3 with monodentate pyridazines. [Cu(L4)(NO3)2] (4) crystallized in the orthorhombic system, space group P212121, with a = 15.148(2) Å, b = 15.562(3) Å, c = 11.064(1) Å, V = 2608.2(7) Å3 and Z = 4 (R = 0.039, Rw = 0.034 for 1864 reflections). Two monodentate pyridazine rings and two bidentate nitrates bind to a pseudo-octahedral copper(II) centre.

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Syntheses and Spectroscopic Studies of Some New Diazaphospholes and Diazaphosphorinanes. Crystal Structure of 4

Zeitschrift für Naturforschung B ◽

10.1515/znb-2005-1001 ◽

2005 ◽

Vol 60 (10) ◽

pp. 1021-1026 ◽

Cited By ~ 12

Author(s):

Khodayar Gholivand ◽

Zahra Shariatinia ◽

Mehrdad Pourayoubi ◽

Sedigheh Farshadian

Keyword(s):

Crystal Structure ◽

Ir Spectroscopy ◽

Spectroscopic Studies ◽

Coupling Constants ◽

Crystalline Lattice ◽

Polymeric Chain ◽

Ring Strain ◽

One Dimensional ◽

X Ray ◽

X Ray Crystallography

New diazaphospholes and diazaphosphorinanes with formula were synthesized and characterized by 1H, 13C, 31P NMR and IR spectroscopy and elemental analysis. The structure of compound 1 has been determined by X-ray crystallography. A one-dimensional polymeric chain was observed in the crystalline lattice produced by intermolecular -P=O. . .H-N- and -C=O. . .H-N-hydrogen bonds. Compounds 1 and 2 contain five-membered rings and show high values for 2J(PNH) and 2J(P,C) coupling constants due to the ring strain. These constants are reduced seriously in compounds with six-membered rings. In compound 6 with CCl3C(O)NH moiety, all phosphorus-hydrogen couplings are zero.

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The first naphthodiazaphosphorinane in the solid phase; syntheses, spectroscopic studies and X-ray crystallography of some new 1,3,2-diheterophosphorus compounds

Structural Chemistry ◽

10.1007/s11224-009-9445-9 ◽

2009 ◽

Vol 20 (3) ◽

pp. 481-488 ◽

Cited By ~ 12

Author(s):

Khodayar Gholivand ◽

Zahra Shariatinia ◽

Sheida Ansar ◽

Seyedeh Mahdieh Mashhadi ◽

Farzaneh Daeepour

Keyword(s):

Solid Phase ◽

Spectroscopic Studies ◽

X Ray ◽

X Ray Crystallography

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Comparison of the Photochemical Reaction of Photoactive Yellow Protein in Crystal with Reaction in Solution1

Spectroscopy An International Journal ◽

10.1155/2003/123586 ◽

2003 ◽

Vol 17 (2-3) ◽

pp. 345-353 ◽

Cited By ~ 4

Author(s):

Eriko Mano ◽

Hironari Kamikubo ◽

Yasushi Imamoto ◽

Mikio Kataoka

Keyword(s):

Photochemical Reaction ◽

Structural Changes ◽

Spectroscopic Studies ◽

Crystalline Lattice ◽

Photoactive Yellow Protein ◽

X Ray ◽

X Ray Crystallography ◽

Solution Condition ◽

Active Intermediate ◽

Ectothiorhodospira Halophila

Photoactive yellow protein (PYP) is a photoreceptor protein for the negative phototaxis ofEctothiorhodospira halophila. The crystal structures of several photo‒intermediates have been revealed by X-ray crystallography. In the crystal structure of the active intermediate, PYPM, no significant structural changes were observed except for the vicinity of the chromophore. On the contrary, spectroscopic studies with solution condition demonstrated that global structural changes occur during the photo‒cycle. In order to reveal the origin of the discrepancies, we measured the reaction kinetics upon illumination under crystal condition and to compare them with those observed under solution condition. The reactive portion decreases with the increase of crystallinity. The rate constant of PYPMdecay also decreases with the increase of crystallinity. These results suggest two possibilities: (1) PYP in crystal does not react by the illumination; (2) the photoreaction rate is highly accelerated in crystal. Consequently, the photoreaction in crystal is considered to be highly influenced by the force constraint from crystalline lattice.

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Coordination chemistry of thioether–pyridazine macrocycles. I. Synthetic, structural, and spectroscopic studies of Cu(II) and Cu(I) complexes of novel thioether–pyridazine macrocycles that contain two or three pyridazine subunits

Canadian Journal of Chemistry ◽

10.1139/v92-236 ◽

1992 ◽

Vol 70 (7) ◽

pp. 1886-1896 ◽

Cited By ~ 9

Author(s):

Liqin Chen ◽

Laurence K. Thompson ◽

John N. Bridson

Keyword(s):

Copper Complexes ◽

Spin Exchange ◽

Spectroscopic Studies ◽

Esr Spectra ◽

Monoclinic System ◽

Space Group ◽

X Ray ◽

X Ray Crystallography ◽

Triclinic System ◽

Square Planar

The preparations of thioether–pyridazine macrocycles containing three (L1) and two (L2) pyridazine subunits and their copper complexes are described. The ligands are characterized by 1H nuclear magnetic resonance and mass spectrometry and in one case by X-ray crystallography, and the complexes by infrared, electronic, and electron spin resonance (esr) spectra and in some cases by X-ray crystallography. The complex [Cu3(L1)2Cl6]•2CHCl3 (1) crystallized in the triclinic system, space group [Formula: see text] with a = 13.661(2) Å, b = 14.174(3) Å, c = 9.412(2) Å, α = 101.08(2)°, β = 96.94(2)°, γ = 75.76(2)°, V = 1728.2(6) Å3, and Z = 2 (R = 0.056, Rw = 0.048 for 2080 reflections). Two monodentate pyridazine rings in each ligand bind to one square-planar copper centre with the third monodentate pyridazine in each ligand linking the two to the central square-planar copper. The complex [Cu(L2)Cl2] (2) crystallized in the orthorhombic system, space group Pnma, with a = 8.571(1) Å, b = 16.104(3) Å, c = 13.961(2) Å, V = 1927(1) Å3, and Z = 4 (R = 0.037, Rw = 0.033 for 1070 reflections). A cis square-planar structure exists for 2 with monodentate pyridazines. [Cu(L2)2]•(ClO4)2•CH3CN•CHCl3 (5) crystallized in the triclinic system, space group [Formula: see text] with a = 12.888(4) Å, b = 17.462(6) Å, c = 10.906(1) Å, α = 96.07(2)°, β = 104.18(2)°, γ = 94.51(2)°, V = 2352(1) Å3, and Z = 2 (R = 0.053, Rw = 0.044 for 2941 reflections). Two ligands involving monodentate pyridazine rings bind to a square-planar copper(II) centre. The protonated ligand salt [L2H](ClO4)•H2O (6) crystallized in the monoclinic system, space group P21/n, with a = 14.762(4) Å, b = 8.637(5) Å, c = 16.267(4) Å, β = 92.78(2)°, V = 2072(1) Å3, and Z = 4 (R = 0.064, Rw = 0.053 for 1456 reflections). No sulfur coordination is observed in these complexes and there is no apparent spin exchange in the trinuclear derivative.

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Coordination chemistry of thioether–pyridazine macrocycles II. Synthesis, structural and spectroscopic studies of dinuclear copper(II) and polynuclear copper(I) and silver(I) complexes of a tetrathiapyridazinophane macrocyclic ligand

Canadian Journal of Chemistry ◽

10.1139/v92-343 ◽

1992 ◽

Vol 70 (11) ◽

pp. 2709-2716 ◽

Cited By ~ 20

Author(s):

Liqin Chen ◽

Laurence K. Thompson ◽

John N. Bridson

Keyword(s):

Macrocyclic Ligand ◽

Silver Ions ◽

Spectroscopic Studies ◽

Binuclear Complexes ◽

Monoclinic System ◽

Magnetic Susceptibility Data ◽

Space Group ◽

X Ray ◽

X Ray Crystallography ◽

Susceptibility Data

The preparation and properties of the thioether–pyridazine macrocycle (L3; C11H16N2S4) containing one pyridazine subunit, and its copper(II), copper(I), and silver(I) complexes are described. Magnetic susceptibility data (5–300 K) for the binuclear complexes [CuL3Cl2]2 (I) and [CuL3Br2]2 (II) have been fitted to the Friedberg magnetization expression with a molecular field correction. Intradimer antiferromagnetic exchange is weak (−2J < 18 cm−1), with even weaker interdimer exchange (−zJ′ < 0.3 cm−1). The complexes [CuL3Cl]x (III) and [AgL3ClO4]x (V) have been characterized by X-ray crystallography. III crystallizes in the triclinic system, space group [Formula: see text], with a = 9.410(2) Å, b = 10.291(2) Å, c = 9.208(2) Å, α = 108.56(1)°, β = 91.82(2)°, γ = 68.04(1)°, V = 780.1(2) Å3, and Z = 2(R = 0.035, Rw = 0.031 for 1856 reflections). The ligand acts as a bidentate, S2, bridge between dinuclear Cu2Cl2 units in a double stranded polymer. III crystallized in the monoclinic system, space group P21/n, with a = 9.382(4) Å, b = 19.274(4) Å, c = 10.190(3) Å, β = 106.35(3)°, V = 1768(1) Å3, and Z = 4 (R = 0.036, Rw = 0.029 for 1776 reflections). The structure consists of a polymeric, two dimensional sheet structure, involving pseudo-tetrahedral silver ions linked by exo-bidentate, S2, ligands and bidentate perchlorates.

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Substituted 4-Acyl-5-methyl-2-phenyl-pyrazol-3-one-phenylhydrazones with Antioxidant Properties: X-Ray Crystal and Spectroscopic Studies

Journal of Chemistry ◽

10.1155/2017/7943051 ◽

2017 ◽

Vol 2017 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Omoruyi G. Idemudia ◽

Anthony I. Okoh ◽

Alexander P. Sadimenko ◽

Eric C. Hosten ◽

Omobola O. Okoh

Keyword(s):

Free Radical ◽

Schiff Bases ◽

Antioxidant Properties ◽

Radical Scavenging ◽

Spectroscopic Studies ◽

Free Radical Scavenging ◽

X Ray ◽

X Ray Crystallography ◽

H Nmr ◽

Radical Scavenging Properties

Phenylhydrazine was reacted with synthesized acylpyrazolone derivatives 4-ethyl-5-methyl-2-phenyl-pyrazol-3-one and 4-propyl-5-methyl-2-phenyl-pyrazol-3-one, to obtain two new azomethine phenylhydrazones, a study in continuation of our probe into the effects of acyl group substitutions on the physicochemical and free radical scavenging properties of acylpyrazolone Schiff bases. The keto imine tautomers of 4-ethyl-5-methyl-2-phenyl-pyrazol-3-one-phenylhydrazone (Empp-Ph) and 4-propyl-5-methyl-2-phenyl-pyrazol-3-one-phenylhydrazone (Prmpp-Ph) according to single X-ray crystallography data which precipitated in good yield are reported. Furthermore they have been characterized by elemental analysis, FTIR, 13C and 1H NMR, and mass-spectroscopy techniques. Both phenylhydrazone Schiff bases crystallize in a triclinic crystal system, each with a space group of P-1 (number 2) having short intramolecular N3—H3…O1 hydrogen interaction between the first hydrazine hydrogen H3 and the pyrazolone oxygen O1. The antioxidant free radical scavenging activities of titled compounds against 2,2-diphenyl-1-picrylhydrazyl (DPPH) showed a positive response almost as good as that of vitamin c under the same conditions, with the propyl substituted 4-propyl-5-methyl-2-phenyl-pyrazol-3-one-phenylhydrazone (Prmpp-Ph) having a stronger activity (calculated IC50 value of 175.66 μg/ml).

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Antifungal and Antioxidant Pyrrole Derivative from Piper Pedicellatum

Natural Product Communications ◽

10.1177/1934578x1300801029 ◽

2013 ◽

Vol 8 (10) ◽

pp. 1934578X1300801 ◽

Cited By ~ 1

Author(s):

Chandan Tamuly ◽

Partha P. Dutta ◽

Manobjyoti Bordoloi ◽

Jayanta Bora

Keyword(s):

Aspergillus Niger ◽

Pathogenic Fungi ◽

Spectroscopic Studies ◽

Curvularia Lunata ◽

Plant Pathogenic Fungi ◽

Arunachal Pradesh ◽

Frap Assay ◽

X Ray ◽

X Ray Crystallography ◽

Fungal Organisms

In continuation of our search for efficient pest control natural products from the flora of the South Eastern Sub-Himalayan biodiversity region, we have investigated wild edible Piper pedicellatum C. DC (Piperaceae) from Arunachal Pradesh, India against five important plant pathogenic fungi through an activity guided method, and a new compound, pedicellamide, was isolated. The structure was determined on the basis of extensive spectroscopic studies and confirmed by X-ray crystallography. The compound exhibited antifungal activities against the phytopathogenic fungal organisms Rhizoctonia solani (MIC 38.4 ± 1.6 μg/mL), Fusarium oxysporum (MIC 29.7 ± 0.8 μg/mL), Aspergillus niger (MIC 48.6 ± 0.7 μg/mL), Puccinia gramini (MIC 46.8 ± 1.4 μg/mL) and Curvularia lunata (MIC 49.1 ± 0.1μg/mL). Additionally, the antioxidant potential of the compound was estimated by DPPH, ABTS and FRAP assay and found to be 2.87 ± 0.20, 2.19 ± 0.13 and 3.96 ± 0.17 VCEAC (μM/g), respectively.

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Difference Fourier Analysis of Glucose Embedded and Frozen Hydrated Purple Membrane

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053164 ◽

1982 ◽

Vol 40 ◽

pp. 74-75

Author(s):

Jules S. Jaffe ◽

Robert M. Glaeser

Keyword(s):

Purple Membrane ◽

Data Set ◽

High Resolution Data ◽

X Ray ◽

X Ray Crystallography ◽

Fourier Techniques ◽

Versus Protein ◽

The Difference ◽

Difference Fourier ◽

Ideal Method

Although difference Fourier techniques are standard in X-ray crystallography it has only been very recently that electron crystallographers have been able to take advantage of this method. We have combined a high resolution data set for frozen glucose embedded Purple Membrane (PM) with a data set collected from PM prepared in the frozen hydrated state in order to visualize any differences in structure due to the different methods of preparation. The increased contrast between protein-ice versus protein-glucose may prove to be an advantage of the frozen hydrated technique for visualizing those parts of bacteriorhodopsin that are embedded in glucose. In addition, surface groups of the protein may be disordered in glucose and ordered in the frozen state. The sensitivity of the difference Fourier technique to small changes in structure provides an ideal method for testing this hypothesis.

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3-D reconstruction of molecular shape from microcrystal thin sections

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100077311 ◽

1983 ◽

Vol 41 ◽

pp. 748-749

Author(s):

S. Cusack ◽

J.-C. Jésior

Keyword(s):

Three Dimensional ◽

Molecular Shape ◽

Biological Molecules ◽

Fourier Space ◽

Single Particles ◽

Thin Sections ◽

Standard Methods ◽

X Ray ◽

X Ray Crystallography ◽

Dimensional Reconstruction

Three-dimensional reconstruction techniques using electron microscopy have been principally developed for application to 2-D arrays (i.e. monolayers) of biological molecules and symmetrical single particles (e.g. helical viruses). However many biological molecules that crystallise form multilayered microcrystals which are unsuitable for study by either the standard methods of 3-D reconstruction or, because of their size, by X-ray crystallography. The grid sectioning technique enables a number of different projections of such microcrystals to be obtained in well defined directions (e.g. parallel to crystal axes) and poses the problem of how best these projections can be used to reconstruct the packing and shape of the molecules forming the microcrystal.Given sufficient projections there may be enough information to do a crystallographic reconstruction in Fourier space. We however have considered the situation where only a limited number of projections are available, as for example in the case of catalase platelets where three orthogonal and two diagonal projections have been obtained (Fig. 1).

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