scholarly journals Threefold Spiral Structure Constructed by 1D Chains of [[M(NCS)2(bpa)2]·biphenyl]n (M = Fe, Co; bpa = 1,2-bis(4-pyridyl)ethane)

Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 97 ◽  
Author(s):  
Satoshi Tokinobu ◽  
Haruka Dote ◽  
Satoru Nakashima
Keyword(s):  
Spin Crossover ◽  
Spiral Structure ◽  
Diffusion Method ◽  
Central Metal ◽  
X Ray ◽  
Pyridine Complex ◽  
1D Chain ◽  
One Step ◽  
Spiral Structures ◽  
1D Chains

Assembled complexes [[M(NCS)2(bpa)2]·biphenyl]n (M = Fe, Co; bpa = 1,2-bis(4-pyridyl)ethane) have been synthesized because [Fe(NCBH3)2(bpa)2·biphenyl]n has a novel threefold spiral structure and shows stepwise spin-crossover phenomenon. We attempted to obtain spiral structures for [[Fe(NCS)2(bpa)2]·biphenyl]n and [[Co(NCS)2(bpa)2]·biphenyl]n using a one-step diffusion method, while the reported spiral structure of [[Fe(NCBH3)2(bpa)2]·biphenyl]n was obtained by diffusion method after synthesizing Fe(II)-pyridine complex. X-ray structural analysis revealed that [[Fe(NCS)2(bpa)2]·biphenyl]n and [[Co(NCS)2(bpa)2]·biphenyl]n had a chiral propeller structure of pyridines around the central metal, and they had a novel spiral structure and chiral space group P3121 without the presence of chiral auxiliaries. It was shown that the host 1D chain, having a chiral propeller structure of pyridines around the central metal along with its concerted interaction with an atropisomer of biphenyl, made a threefold spiral structure.

A Mn(II) Metal-Organic Framework Constructed from a Tetrahedral Silicon-Cored Ligand

2013 ◽  
Vol 275-277 ◽  
pp. 2367-2370
Author(s):  
Qing Yu Ma ◽  
Rui Fang Guan ◽  
Guo Zhong Li ◽  
Deng Xu Wang
Keyword(s):  
Single Crystal ◽  
Metal Organic Framework ◽  
Diffusion Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Slow Diffusion ◽  
Sheet Structure ◽  
Metal Organic ◽  
1D Chains ◽  
Organic Framework

A novel metal-organic framework, MnCl2(BIPS)2•2CH3OH•2H2O (1) were synthesized from MnCl2 and a tetrahedral silicon-cored ligand, Me2Si(p-C6H4-imdazol-1-yl)2 (BIPS) under the slow diffusion method. The structure was determined by single-crystal X-ray diffraction. Complex 1 is a 2D sheet structure constructed from 1D chains with 34-atom metallamacrocycles.

scholarly journals Solvent-Induced Hysteresis Loop in Anionic Spin Crossover (SCO) Isomorph Complexes

2021 ◽  
Author(s):  
Emmelyne Cuza ◽  
Samia Benmansour ◽  
Nathalie Cosquer ◽  
Francoise Conan ◽  
Carlos J. Gómez-García ◽  
...  
Keyword(s):  
Spin Crossover ◽  
Magnetic Studies ◽  
Tridentate Ligands ◽  
Tripodal Ligand ◽  
X Ray ◽  
Mononuclear Complexes ◽  
One Step ◽  
Step Transition ◽  
Heating Up ◽  
Crystal Characterizations

Reactions of Fe(II) with the tris-(pyridin-2-yl)ethoxymethane (py3C-OEt) tripodal ligand in presence of the pseudohalide ancillary NCE- (E = S, Se, BH3) ligands led to a series of three mononuclear complexes formulated as [Fe(py3C-OEt)2][Fe(py3C-OEt)(NCE)3]2·2CH3CN, with E = S (1), BH3 (2) and Se (3). Single crystal characterizations (complexes 1-2) and X-ray powder diffraction (complexes 1-3) reveal monomeric isomorph structures formed by the spin crossover (SCO) anionic [Fe(py3C-OEt)(NCE)3] complex, associated with the low spin (LS) cationic [Fe(py3C-OEt)2]2+ complex and two solvent acetonitrile molecules. In the [Fe(py3C-OEt)2]2+ cation, the Fe(II) is coordinated by two py3C-OEt tridentate ligands, while the [Fe(py3C-OEt)(NCE)3] anion displays a hexacoordinated environment involving three N-donor atoms of one py3C-OEt ligand and three nitrogen atoms arising from of the three (NCE) coligands. The magnetic studies show the presence of gradual SCO behavior for the three complexes: a one-step transition around 205 K for 1 and two step-transitions for compounds 2 and 3, centred at 245 K and 380 K for 2, and at 170 K and 298 K for 3. The magnetic behaviors of complexes 1 and 2 remain unchanged when heating up to 500 K, while complex 3 shows significant changes which are caused by the crystallisation solvent loss above room temperature.

scholarly journals Synthesis, Structure, and Thermal Stability of Supramolecular Polymers with 1D Chain: [M(BPP)2(TBTA)(H2O)2]n[M=Mn(1),Co(2)]

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Yan Liu ◽  
Ling-Ling Gao ◽  
Xu-Yan Lv ◽  
Jian-Feng Liu ◽  
Tuo-Ping Hu
Keyword(s):  
Complex Compounds ◽  
Supramolecular Polymers ◽  
Triclinic Crystal System ◽  
X Ray ◽  
Carboxylate Groups ◽  
Distorted Octahedral ◽  
1D Chain ◽  
Thermal Stability Of ◽  
1D Chains ◽  
Octahedral Configuration

Two supramolecular polymers [M(BPP)2(TBTA)(H2O)2]n[M=Mn(1),Co(2)] have been constructed from 2,3,5,6-tetrabromoterephthalic acid (H2TBTA) and 1,3-bis(4-pyridyl)propane (BPP) ligands in water-methanol dissolvant. Single-crystal X-ray and powder diffraction, IR spectroscopy, thermogravimetric analysis, and elemental analysis were employed to characterize all samples. Both of the complex compounds 1 and 2 belong to triclinic crystal system with P-1 space group. The crystal structures analysis indicates that the metal atom coordinated by two carboxylate groups from different TBTA ligands, two BPP, molecules and two H2O molecules formed a slightly distorted octahedral configuration. The compounds of 1 and 2 are 1D chains made with TBTA spacers, BPP molecules, and H2O molecules.

Spin State Transition Studied by Means of Optical Microscope

2010 ◽  
Vol 163 ◽  
pp. 46-50 ◽  
Author(s):  
Maciej Zubko ◽  
Paweł Zajdel ◽  
Joachim Kusz
Keyword(s):  
Spin State ◽  
Spin Crossover ◽  
State Transition ◽  
Optical Microscope ◽  
X Ray ◽  
Spin State Transition ◽  
Transmission Geometry ◽  
One Step ◽  
Analysis Of Change

We have tested a new method which allows assigning the spin state of the spin crossover (SCO) crystal in-situ during the diffraction experiment. The method is based on the analysis of change of the colour of the SCO compounds. We have found that the off-line setup in transmission geometry is reliable in assigning the magnitude of high spin molecules fraction (γHS) and the character (one step, many steps, histeresis) of the SCO transition. Later on, this method has been used in the in-situ measurements directly on X-ray four-circle diffractometer.

Synthesis and Crystal Structure of a New 3D Copper B-Paradodecatungstate Compound: [Na2(H2O)8][Na8(H2O)20][Cu(en)2][W12O42] · 3H2O

2009 ◽  
Vol 64 (3) ◽  
pp. 269-273 ◽  
Author(s):  
Xiuhong Xu ◽  
Fang Luo ◽  
Weihong Luo ◽  
Ji Chen
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
Ir Spectroscopy ◽  
Complex Cation ◽  
X Ray Diffraction ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
1D Chain ◽  
3D Framework ◽  
1D Chains

A new polyoxotungstate complex [Na2(H2O)8][Na8(H2O)20][Cu(en)2][W12O42] ・3H2O (1) (en = ethylenediamine) has been synthesized in aqueous solution and characterized by elemental analysis, IR spectroscopy and TG analysis, together with a single crystal X-ray diffraction study. In compound 1, the Cu(en)22+ complex cation links the [W12O42]12− anions to form a 1D chain, and the 1D chains are further interconnected with Na8(H2O)208+ and Na2(H2O)82+ cations to construct a new 3D framework.

Technology of high quality protein crystals’ obtaining aboard the ISS at execution of joint Japanese–Russian experiments

2020 ◽  
pp. 5-25
Author(s):  
Koji INAKA ◽  
Saori ICHIMIZU ◽  
Izumi YOSHIZAKI ◽  
Kiyohito KIHIRA ◽  
Elena G. LAVRENKO ◽  
...  
Keyword(s):  
Drug Design ◽  
International Space Station ◽  
Space Station ◽  
Protein Crystals ◽  
Diffusion Method ◽  
X Ray Diffraction ◽  
High Quality ◽  
International Space ◽  
X Ray ◽  
High Quality Protein

A series of space experiments aboard the International Space Station (ISS) associated with high-quality Protein Crystal Growth (PCG) in microgravity conditions can be considered as a unique and one of the best examples of fruitful collaboration between Japanese and Russian scientists and engineers in space, which includes also other ISS International Partners. X-ray diffraction is still the most powerful tool to determine the protein three dimensional structure necessary for Structure based drug design (SBDD). The major purpose of the experiment is to grow high quality protein crystals in microgravity for X-ray diffraction on Earth. Within one and a half decade, Japan and Russia have established an efficient process over PCG in space to support latest developments over drug design and structural biology. One of the keys for success of the experiment lies in how precisely pre-launch preparations are made. Japanese party provides flight equipment for crystallization and ensures the required environment to support the experiment aboard of the ISS’s Kibo module, and also mainly takes part of the experiment ground support such as protein sample characterization, purification, crystallization screening, and solution optimization for microgravity experiment. Russian party is responsible for integration of the flight items equipped with proteins and precipitants on board Russian transportation space vehicles (Soyuz or Progress), for delivery them at the ISS, transfer to Kibo module, and returning the experiments’ results back on Earth aboard Soyuz manned capsule. Due to close cooperation of the parties and solid organizational structure, samples can be launched at the ISS every half a year if the ground preparation goes smoothly. The samples are crystallized using counter diffusion method at 20 degree C for 1–2.5 months. After samples return, the crystals are carefully taken out from the capillary, and frozen for X-ray diffraction at SPring8 facility in Japan. Extensive support of researchers from both countries is also a part of this process. The paper analyses details of the PCG experiment scheme, unique and reliable technology of its execution, and contains examples of the application. Key words: International Space Station, Protein crystals, Microgravity, International collaboration.

Influence of ligand substituent conformation on the spin state of an iron(ii)/di(pyrazol-1-yl)pyridine complex

2021 ◽  
Vol 50 (10) ◽  
pp. 3464-3467
Author(s):  
Rafal Kulmaczewski ◽  
Mark J. Howard ◽  
Malcolm A. Halcrow
Keyword(s):  
Spin State ◽  
Spin Crossover ◽  
Solution Phase ◽  
Pyridine Complex

The temperature of the solution-phase spin-crossover equilibrium in iron(ii) complexes of 4-alkylsulfanyl-2,6-di{pyrazol-1-yl}pyridine (bppSR) complexes depends strongly on the alkylsulfanyl substituent.

scholarly journals Optical, XPS and XRD Studies of Semiconducting Copper Sulfide Layers on a Polyamide Film

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Valentina Krylova ◽  
Mindaugas Andrulevičius
Keyword(s):  
Photoelectron Spectroscopy ◽  
Copper Sulfide ◽  
Diffusion Method ◽  
X Ray Diffraction ◽  
Xps Spectra ◽  
X Ray ◽  
Xrd Studies ◽  
Polyamide Film ◽  
Indirect Band Gap ◽  
Xrd Method

Copper sulfide layers were formed on polyamide PA 6 surface using the sorption-diffusion method. Polymer samples were immersed for 4 and 5 h in 0.15 mol⋅  solutions and acidified with HCl (0.1 mol⋅) at . After washing and drying, the samples were treated with Cu(I) salt solution. The samples were studied by UV/VIS, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) methods. All methods confirmed that on the surface of the polyamide film a layer of copper sulfide was formed. The copper sulfide layers are indirect band-gap semiconductors. The values of are 1.25 and 1.3 eV for 4 h and 5 h sulfured PA 6 respectively. Copper XPS spectra analyses showed Cu(I) bonds only in deeper layers of the formed film, while in sulfur XPS S 2p spectra dominating sulfide bonds were found after cleaning the surface with ions. It has been established by the XRD method that, beside , the layer contains as well. For PA 6 initially sulfured 4 h, grain size forchalcocite, , was  nm and fordjurleite, , it was 54.17 nm. The sheet resistance of the obtained layer varies from 6300 to 102 .

scholarly journals Crystallization and preliminary X-ray diffraction analysis of the Csu pili CsuC–CsuA/B chaperone–major subunit pre-assembly complex fromAcinetobacter baumannii

2015 ◽  
Vol 71 (6) ◽  
pp. 770-774 ◽  
Author(s):  
Natalia Pakharukova ◽  
Minna Tuittila ◽  
Sari Paavilainen ◽  
Anton Zavialov
Keyword(s):  
Diffusion Method ◽  
X Ray Diffraction ◽  
Hanging Drop ◽  
Unit Cell Parameters ◽  
Gram Negative ◽  
X Ray ◽  
Cell Parameters ◽  
Abiotic Surfaces ◽  
Vapour Diffusion ◽  
Fimbrial Adhesins

The attachment of many Gram-negative pathogens to biotic and abiotic surfaces is mediated by fimbrial adhesins, which are assembledviathe classical, alternative and archaic chaperone–usher (CU) pathways. The archaic CU fimbrial adhesins have the widest phylogenetic distribution, yet very little is known about their structure and mechanism of assembly. To elucidate the biogenesis of archaic CU systems, structural analysis of the Csu fimbriae, which are used byAcinetobacter baumanniito form stable biofilms and cause nosocomial infection, was focused on. The major fimbriae subunit CsuA/B complexed with the CsuC chaperone was purified from the periplasm ofEscherichia colicells co-expressing CsuA/B and CsuC, and the complex was crystallized in PEG 3350 solution using the hanging-drop vapour-diffusion method. Selenomethionine-labelled CsuC–CsuA/B complex was purified and crystallized under the same conditions. The crystals diffracted to 2.40 Å resolution and belonged to the hexagonal space groupP6422, with unit-cell parametersa=b= 94.71,c = 187.05 Å, α = β = 90, γ = 120°. Initial phases were derived from a single anomalous diffraction (SAD) experiment using the selenomethionine derivative.

Spin-crossover iron(II) long-chain complex with slow spin equilibrium at low temperature

2021 ◽  
Author(s):  
Qi Zhao ◽  
Jin-Peng Xue ◽  
Zhi-Kun Liu ◽  
Zi-Shuo Yao ◽  
Jun Tao
Keyword(s):  
Low Temperature ◽  
Single Crystal ◽  
Spin Crossover ◽  
Chain Complex ◽  
Mononuclear Complex ◽  
X Ray ◽  
Alkyl Chains ◽  
Long Chain

A mononuclear complex with long alkyl chains, [FeII(H2Bpz2)2(C9bpy)] (1; H2Bpz2 = dihydrobis(1-pyrazolyl)borate, C9bpy = 4,4'-dinonyl-2,2'-bipyridine), was synthesized. Single-crystal X-ray crystallographic studies revealed that - and - forms of the complex...

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