scholarly journals Macrocyclic “tet a”-Derived Cobalt(III) Complex with a N,N′-Disubstituted Hexadentate Ligand: Crystal Structure, Photonuclease Activity, and as a Photosensitizer

ACS Omega ◽  
2021 ◽  
Author(s):  
Murugan Sethupathi ◽  
Boobalan Thulasinathan ◽  
Nallathambi Sengottuvelan ◽  
Kumar Ponnuchamy ◽  
Franc Perdih ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hexadentate Ligand

scholarly journals Spin Cross-Over (SCO) Complex Based on Unsymmetrical Functionalized Triazacyclononane Ligand: Structural Characterization and Magnetic Properties

2019 ◽  
Vol 5 (1) ◽  
pp. 19 ◽  
Author(s):  
Merzouk Halit ◽  
Mélissa Roger ◽  
Véronique Patinec ◽  
Said Yefsah ◽  
Carlos Gómez-García ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Thermal Decomposition ◽  
Magnetic Properties ◽  
Nmr Spectroscopy ◽  
Functional Groups ◽  
Structural Characterization ◽  
Spin Crossover ◽  
Magnetic Studies ◽  
Dsc Measurements ◽  
Hexadentate Ligand

The unsymmetrical ligand 1-(2-aminophenyl)-4,7-bis(pyridin-2-ylmethyl)-1,4,7-triazacyclononane (L6) has been prepared and characterized by NMR spectroscopy. The L6 ligand is based on the triazamacrocycle (tacn) ring that is functionalized by two flexible 2-pyridylmethyl and one rigid 2-aminophenyl groups. Reaction of this ligand with Fe(ClO4)2·xH2O led to the complex [Fe(L6)](ClO4)2 (1), which was characterized as the first Fe(II) complex based on the unsymmetrical N-functionalized tacn ligand. The crystal structure revealed a discrete monomeric [FeL6]2+ entity in which the unsymmetrical N-functionalized triazacyclononane molecule (L6) acts as hexadentate ligand. As observed in the few parent examples that are based on the symmetrical N-functionalized tacn ligands, the triazacyclononane ring is facially coordinated and the N-donor atoms of the three functional groups (two pyridine and one aniline groups) are disposed in the same side of the tacn ring, leading to a distorted FeN6 environment. The magnetic studies of 1 revealed the presence of an incomplete spin crossover (SCO) transition above 425 K, whose progress would be prevented by a very exothermic thermal decomposition at ca. 472 K, as shown by thermogravimetric and DSC measurements.

scholarly journals Synthesis and Structure of 2D Cobalt(II)-tartrate Hydrate Coordination Polymers Crystallised from Aqueous Solution

2018 ◽  
Vol 13 (2) ◽  
pp. 213 ◽  
Author(s):  
Mohammad Misbah Khunur ◽  
Yuniar Ponco Prananto
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
Coordination Polymer ◽  
Single Crystal ◽  
Chemical Reaction ◽  
Coordination Polymers ◽  
Room Temperature ◽  
Reaction Engineering ◽  
X Ray ◽  
Hexadentate Ligand

Cobalt(II)-tartrate hydrate coordination polymer is successfully crystallisedfrom aqueous solution at room temperature. Unlike previous methods, diammonium tartrate was used and reacted directly with an aqueous solution of cobalt(II). Single crystal X-ray and ATR-IR analyses were performed toward the synthesized crystal. The crystal structure displaysa (6,3) 2D sheet which then grow into a 3D hydrogen-bonded network. Tetra- and hexa-dentate dianionic tartaric ligands are observed in the crystal structure, in which the hexadentate ligand connects four different cobalt centres. This method is considered feasible, affordable, and simple for the production of functional polymeric cobalt(II)-tartrate hydrate. Copyright © 2018 BCREC Group. All rights reservedReceived: 17th July 2017; Revised: 30th October 2017; Accepted: 30th October 2017; Available online:   11st June 2018; Published regularly: 1st August 2018How to Cite: Khunur, M.M., Prananto, Y.P. (2018). Synthesis and Structure of 2D Cobalt(II)-tartrate Hydrate Coordination Polymers Crystallised from Aqueous Solution. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (2): 213-219 (doi:10.9767/bcrec.13.2.1342.213-219)

scholarly journals Design and synthesis of a cyclitol-derived scaffold with axial pyridyl appendages and its encapsulation of the silver(I) cation

2010 ◽  
Vol 6 ◽  
pp. 1022-1024 ◽  
Author(s):  
Pierre-Marc Léo ◽  
Christophe Morin ◽  
Christian Philouze
Keyword(s):  
Crystal Structure ◽  
Design And Synthesis ◽  
Hexadentate Ligand

Conversion of a myo-inositol derivative into a scyllo-inositol-derived scaffold with C 3 v symmetry bearing three axial pyridyl appendages is presented. This pre-organized hexadentate ligand allows complexation of silver(I). The crystal structure of the complex was established.

Synthesis, Spectroscopy and Structure of the Cobalt(III) Complex of the Hexadentate Ligand 5-(4-Amino-2-thiabutyl)-5-methyl-3,7-dithianonane-1,9-diamine

1993 ◽  
Vol 46 (11) ◽  
pp. 1799 ◽  
Author(s):  
TM Donlevy ◽  
LR Gahan ◽  
TW Hambley ◽  
KL Mcmahon ◽  
R Stranger
Keyword(s):  
Crystal Structure ◽  
Progressive Increase ◽  
Ligand Field ◽  
Octahedral Symmetry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hexadentate Ligand ◽  
Symmetry Result ◽  
Ligand Field Parameters ◽  
Systematic Reduction

A revised synthesis of the hexadentate ligand 5-(4-amino-2-thiabutyl)-5-methyl-3,7-dithianon- ane-1,9-diamine (N3S3) is reported. Reaction between the sodium salt of 2-aminoethanethiol and 1,1,1-tris([( tolylsulfonyl )oxy]methyl)ethane in refluxing ethanol results in the formation of the hexadentate ligand N3S3. The preparation of the nickel(II) and cobalt(III) complexes is reported. The crystal structure of [Co(N3S3)](ClO4)3.H2O has been determined by X-ray diffraction methods and refined to a residual of 0.044 for 3696 independent observed reflections. The crystals are monoclinic, P21/n, a 9.314(4), b 15.581(6), c 17.026(3) Ǻ, β 90.30(4)°. Low temperature (c.10 K) absorption spectra are reported for [Co(N3S3)]3+ and the analogous encapsulated complex [Co(AMN3S3sarH)]4+ where both the spin-allowed 1A1g → 1T1g, 1T2g and spin-forbidden 1A1g → 3T1g, 3T2g were observed. Ligand -field calculations based on octahedral symmetry result in the ligand -field parameters B 461, C 3075, Dq 2303 cm-1, and B 462, C 3085, Dq 2266 cm-1 for the [Co(N3S3)]3+ and [Co(AMN3S3sarH)]4+ complexes, respectively. A systematic reduction occurs in the Racah B parameter of between 25 and 30 cm-1 for each additional thioether donor in the series of complexes N6-xSx (x = 0, 1, 2, 3). In addition, there is evidence for a progressive increase in the Racah C/B ratio with increasing number of thioether donors in this series.

Crystal Structure Determination of Glycerol-Containing Lipids from Electron Diffraction Data. Use of Analog Compounds Based upon Configurational Isomers of Cyclopentane-1, 2, 3-TRIOL

1977 ◽  
Vol 35 ◽  
pp. 24-25
Author(s):  
Douglas L. Dorset ◽  
Anthony J. Hancock
Keyword(s):  
Crystal Structure ◽  
Electron Diffraction ◽  
Diffraction Data ◽  
Structure Determination ◽  
Crystal Surface ◽  
Coherent Scattering ◽  
Crystal Structure Determination ◽  
Electron Diffraction Data ◽  
Polar Group ◽  
Axis Orientation

Lipids containing long polymethylene chains were among the first compounds subjected to electron diffraction structure analysis. It was only recently realized, however, that various distortions of thin lipid microcrystal plates, e.g. bends, polar group and methyl end plane disorders, etc. (1-3), restrict coherent scattering to the methylene subcell alone, particularly if undistorted molecular layers have well-defined end planes. Thus, ab initio crystal structure determination on a given single uncharacterized natural lipid using electron diffraction data can only hope to identify the subcell packing and the chain axis orientation with respect to the crystal surface. In lipids based on glycerol, for example, conformations of long chains and polar groups about the C-C bonds of this moiety still would remain unknown.One possible means of surmounting this difficulty is to investigate structural analogs of the material of interest in conjunction with the natural compound itself. Suitable analogs to the glycerol lipids are compounds based on the three configurational isomers of cyclopentane-1,2,3-triol shown in Fig. 1, in which three rotameric forms of the natural glycerol derivatives are fixed by the ring structure (4-7).

Spherulitic crystal growth in the prodissoconch larval of Crassostrea virginica

1983 ◽  
Vol 41 ◽  
pp. 518-519
Author(s):  
George G. Cocks ◽  
Louis Leibovitz ◽  
DoSuk D. Lee
Keyword(s):  
Crystal Structure ◽  
Crassostrea Virginica ◽  
Crystal Orientation ◽  
Developmental Changes ◽  
Gastrula Stage ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Stages Of Growth ◽  
Early Stages ◽  
Initial Deposition

Our understanding of the structure and the formation of inorganic minerals in the bivalve shells has been considerably advanced by the use of electron microscope. However, very little is known about the ultrastructure of valves in the larval stage of the oysters. The present study examines the developmental changes which occur between the time of conception to the early stages of Dissoconch in the Crassostrea virginica(Gmelin), focusing on the initial deposition of inorganic crystals by the oysters.The spawning was induced by elevating the temperature of the seawater where the adult oysters were conditioned. The eggs and sperm were collected separately, then immediately mixed for the fertilizations to occur. Fertilized animals were kept in the incubator where various stages of development were stopped and observed. The detailed analysis of the early stages of growth showed that CaCO3 crystals(aragonite), with orthorhombic crystal structure, are deposited as early as gastrula stage(Figuresla-b). The next stage in development, the prodissoconch, revealed that the crystal orientation is in the form of spherulites.

Transmission Electron Microscopy studies of the vacancy ordering in YSI2-X thin films

1991 ◽  
Vol 49 ◽  
pp. 562-563
Author(s):  
F.-R. Chen ◽  
T. L. Lee ◽  
L. J. Chen
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Thin Films ◽  
Diffraction Pattern ◽  
Annealing Temperature ◽  
Lattice Mismatch ◽  
Si Substrate ◽  
Metal Thin Films ◽  
Transmission Electron ◽  
Vacancy Ordering

YSi2-x thin films were grown by depositing the yttrium metal thin films on (111)Si substrate followed by a rapid thermal annealing (RTA) at 450 to 1100°C. The x value of the YSi2-x films ranges from 0 to 0.3. The (0001) plane of the YSi2-x films have an ideal zero lattice mismatch relative to (111)Si surface lattice. The YSi2 has the hexagonal AlB2 crystal structure. The orientation relationship with Si was determined from the diffraction pattern shown in figure 1(a) to be and . The diffraction pattern in figure 1(a) was taken from a specimen annealed at 500°C for 15 second. As the annealing temperature was increased to 600°C, superlattice diffraction spots appear at position as seen in figure 1(b) which may be due to vacancy ordering in the YSi2-x films. The ordered vacancies in YSi2-x form a mesh in Si plane suggested by a LEED experiment.

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