Synthesis and X-ray crystallography of nonanuclear cobalt cluster and mononuclear cobalt complex: Effect of phosphine on the formation of cobalt complexes

Polyhedron ◽  
2020 ◽  
Vol 191 ◽  
pp. 114803
Author(s):  
Tomohiko Hamaguchi ◽  
Daiji Ono ◽  
Yutaro Matsuda ◽  
Satoshi Kawata
Keyword(s):  
Cobalt Complex ◽  
Cobalt Complexes ◽  
Complex Effect ◽  
X Ray ◽  
Cobalt Cluster ◽  
X Ray Crystallography ◽  
Mononuclear Cobalt

scholarly journals Catalytic Efficacy of 2,2′-Bipyridine Cobalt(II) Complex: Hydrothermal Synthesis, X-Ray Structure and Aerobic Epoxidation of Alkenes

2020 ◽  
Vol 33 (1) ◽  
pp. 10-14
Author(s):  
RAJESH BERA
Keyword(s):  
Crystal Structure ◽  
Hydrothermal Synthesis ◽  
Atmospheric Pressure ◽  
Active Catalyst ◽  
High Yield ◽  
X Ray ◽  
X Ray Crystallography ◽  
Mononuclear Cobalt ◽  
Epoxidation Of Alkenes ◽  
Acetonitrile Medium

A mononuclear cobalt(II) complex, [Co(bpy)2(NO3)](NO3)·3H2O (1) (bpy = 2,2′-bipyridine) has been synthesized hydrothermally and the crystal structure was characterized by X-ray crystallography. Complex 1 is capable of activating aerobic oxygen at atmospheric pressure. [Co(bpy)2(NO3)](NO3)·3H2O (1) was used as an active catalyst for the aerobic epoxidaion of various alkenes with isobutyraldehyde as co-reductant in acetonitrile medium. Complex 1 catalyzes the epoxidaion reaction efficiently, which reflected in high yield of products with desired selectivity.

scholarly journals Use of the 2-Pyridinealdoxime/N,N′-Donor Ligand Combination in Cobalt(III) Chemistry: Synthesis and Characterization of Two Cationic Mononuclear Cobalt(III) Complexes

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Konstantis F. Konidaris ◽  
Catherine P. Raptopoulou ◽  
Vassilis Psycharis ◽  
Spyros P. Perlepes ◽  
Evy Manessi-Zoupa ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
General Type ◽  
Reaction System ◽  
Synthesis And Characterization ◽  
Chelating Ligands ◽  
Donor Ligand ◽  
X Ray ◽  
X Ray Crystallography ◽  
Mononuclear Cobalt

The use of 2-pyridinealdoxime (paoH)/N,N′-donor ligand (L-L) “blend” in cobalt chemistry has afforded two cationic mononuclear cobalt(III) complexes of the general type [Co(pao)2(L-L)]+, where L-L = 1,10-phenanthroline (phen) and 2,2′-bipyridine (bpy). The CoCl2/paoH/L-L (1 : 2 : 1) reaction system in MeOH gives complexes [CoIII(pao)2(phen)]Cl⋅2H2O (1⋅2H2O) and [CoIII(pao)2(bpy)]Cl⋅1.5MeOH (2⋅1.5MeOH). The structures of the complexes were determined by single-crystal X-ray crystallography. The CoIIIions are six-coordinate, surrounded by three bidentate chelating ligands, that is, two pao-and one phen or bpy. The deprotonated oxygen atom of the pao-ligand remains uncoordinated and participates in hydrogen bonding with the solvate molecules. IR data of the complexes are discussed in terms of the nature of bonding and the known structures.

Tuning of Spin Crossover Properties in a Series of Mononuclear Cobalt(II) Complexes Based on Macrocyclic Tetradentate Ligand and Pseudohalide Coligands

2020 ◽  
Author(s):  
Subrata Ghosh ◽  
S Selvamani ◽  
Sujit Kamilya ◽  
Sakshi Mehta ◽  
Abhishake Mondal
Keyword(s):  
Single Crystal ◽  
Spin Crossover ◽  
Variable Temperature ◽  
Tetradentate Ligand ◽  
X Ray ◽  
Tert Butyl ◽  
X Ray Crystallography ◽  
Mononuclear Cobalt

The three mononuclear cobalt(II) complexes, [Co(L)(NCX)2] (L = N,N'-di-tert-butyl-2,11-diaza[3,3](2,6)pyridinophane, and X = S (1), Se (2), and [C(CN)2] (3)), have been synthesized and characterized using variable temperature single-crystal X-ray crystallography,...

Synthesis and structure of 3,5-dimethylpyrazolyl iron and cobalt dinitrosyl dimers

1979 ◽  
Vol 57 (23) ◽  
pp. 3119-3125 ◽  
Author(s):  
Kenneth S. Chong ◽  
Steven J. Rettig ◽  
Alan Storr ◽  
James Trotter
Keyword(s):  
Cobalt Complex ◽  
Cobalt Complexes ◽  
Iron Complex ◽  
Synthesis And Characterization ◽  
Monoclinic Space Group ◽  
Boat Conformation ◽  
Coordination Geometry ◽  
X Ray ◽  
Metal Atoms

The synthesis and characterization of two 3,5-dimethylpyrazolyl metal dinitrosyl dimers [(N2C5H7)M(NO)2]2 (where M = Fe or Co) are described and their X-ray crystal structures detailed. Both complexes crystallize in the monoclinic space group C2/c, a = 23.848(2), 23.722(4), b = 10.7775(7), 10.6888(6), c = 14.764(1), 14.712(2) Å, β = 117.366(6), 117.094(7)°, Z = 8 (for the iron and cobalt complexes respectively). The structure of the iron complex was solved by Patterson and Fourier syntheses. The cobalt complex is isomorphous with the iron analog. Both structures were refined by full-matrix least-squares procedures to R = 0.028 and 0.035 for 4251 and 3376 reflections with I ≥ 3σ(I) respectively. Both complexes adopt a boat conformation for the central M—(N—N)2—M ring and display significantly non-linear M—N—O groups. The coordination geometry about the metal atoms is distorted tetrahedral. Important molecular dimensions (distances corrected for libration) are: mean Fe—N(pyrazolyl), 2.009(5), mean Fe—NO, 1.696(2) Å, Fe—N—O, 158.5(3)–168.2(2)°, mean Co—N(pyrazolyl), 1.992(7), Co—NO, 1.646(3)–1.680(3) Å, and Co—N—O, 161.6(3)–173.5(3)°. The iron complex is paramagnetic with formally "17-electron" iron atoms. Both structures are compared with similar four-coordinate metal dinitrosyl compounds.

scholarly journals Copolymerization of epoxides with cyclic anhydrides catalyzed by dinuclear cobalt complexes

2018 ◽  
Vol 14 ◽  
pp. 2779-2788 ◽  
Author(s):  
Yo Hiranoi ◽  
Koji Nakano
Keyword(s):  
Catalytic Activity ◽  
Cobalt Complex ◽  
Cobalt Complexes ◽  
High Catalytic Activity ◽  
Synthetic Method ◽  
Salen Complex ◽  
Salen Complexes ◽  
Mononuclear Cobalt ◽  
Cyclic Anhydrides ◽  
Alternating Copolymerization

The alternating copolymerization of epoxides with cyclic anhydrides (CAs) is a highly diverse synthetic method for polyesters as the polymers’ architectures and properties can be easily controlled depending on the combination of two monomers. Thus, a variety of catalyst designs has been reported to prepare the desired copolymers efficiently. We herein report dinuclear cobalt–salen complexes with a benzene ring as a linker and their activities in copolymerization reactions. The dinuclear cobalt complexes showed a higher catalytic activity for the copolymerization of propylene oxide with phthalic anhydride than the corresponding mononuclear cobalt–salen complex and achieved one of the highest turnover frequencies ever reported. A variety of epoxides and CAs were also found to be copolymerized successfully by the dinuclear cobalt complex with a high catalytic activity.

A Mononuclear Cobalt(II) Complex Containing Pyridine Betaine and Thiocyanate Ligands: Triaquabis(pyridinioacetato-O)(thiocyanato-N)cobalt(1+) Tetra(thiocyanato-N)cobaltate(2-)

1992 ◽  
Vol 45 (8) ◽  
pp. 1307 ◽  
Author(s):  
MY Chow ◽  
TCW Mak
Keyword(s):  
Hydrogen Bonds ◽  
Molecular Hydrogen ◽  
Cobalt Atom ◽  
One Dimensional ◽  
X Ray ◽  
X Ray Crystallography ◽  
Mononuclear Cobalt ◽  
Distorted Octahedral ◽  
Thiocyanate Ligand

The cobalt(II) complex [Co(C5H5NCH2CO2)2(NCS)(H2O)3]2 [Co(NCS)4] has been synthesized, and characterized by X-ray crystallography. The complex comprises distorted octahedral [CO(C5H5NCH2CO2)2(NCS)(H2O)3]+ cations, in which the cobalt atom is surrounded by two trans monodentate pyridine betaine ligands, one N-bonded thiocyanate ligand and three aqua ligands, as well as distorted tetrahedral [CO(NCS)4]2- anions. Two-thirds of the aqua ligands form intra- and inter-molecular hydrogen bonds with the coordinated and uncoordinated carboxylate oxygens , linking the cations into a one-dimensional polymeric block directed along a 21 axis.

Difference Fourier Analysis of Glucose Embedded and Frozen Hydrated Purple Membrane

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.

3-D reconstruction of molecular shape from microcrystal thin sections

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).

Electron microscopy of rabbit FC crystals

1983 ◽  
Vol 41 ◽  
pp. 730-731
Author(s):  
Robert A. Grant ◽  
Laura L. Degn ◽  
Wah Chiu ◽  
John Robinson
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Molecular Replacement ◽  
X Ray ◽  
X Ray Crystallography ◽  
Resolution Electron ◽  
Replacement Technique ◽  
Hydrated Crystal ◽  
Molecular Structure Analysis

Proteolytic digestion of the immunoglobulin IgG with papain cleaves the molecule into an antigen binding fragment, Fab, and a compliment binding fragment, Fc. Structures of intact immunoglobulin, Fab and Fc from various sources have been solved by X-ray crystallography. Rabbit Fc can be crystallized as thin platelets suitable for high resolution electron microscopy. The structure of rabbit Fc can be expected to be similar to the known structure of human Fc, making it an ideal specimen for comparing the X-ray and electron crystallographic techniques and for the application of the molecular replacement technique to electron crystallography. Thin protein crystals embedded in ice diffract to high resolution. A low resolution image of a frozen, hydrated crystal can be expected to have a better contrast than a glucose embedded crystal due to the larger density difference between protein and ice compared to protein and glucose. For these reasons we are using an ice embedding technique to prepare the rabbit Fc crystals for molecular structure analysis by electron microscopy.

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