scholarly journals 2D Layer Arrangement of Solely [HS-HS] or [LS-LS] Molecules in the [HS-LS] State of a Dinuclear Fe(II) Spin Crossover Complex

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 448
Author(s):  
Fabian Fürmeyer ◽  
Luca M. Carrella ◽  
Eva Rentschler
Keyword(s):  
Crystal Structure ◽  
Spin Crossover ◽  
Crystal Packing ◽  
Spin Transition ◽  
High Spin State ◽  
Crystal Structure Analysis ◽  
Magnetic Data ◽  
The Novel ◽  
Layer Arrangement ◽  
Dinuclear Iron

Herein we report the synthesis and characterization of three new dinuclear iron(II) complexes [FeII2(I4MTD)2](F3CSO3)4 (C1), [FeII2(I4MTD)2](ClO4)4 (C2) and [FeII2(I4MTD)2](BF4)4 (C3) based on the novel ligand (I4MTD = 2,5-bis{[(1H-imidazol-4-ylmethyl)amino]methyl}-1,3,4-thiadiazole). Magnetic susceptibility measurements and single-crystal structure analysis show that the iron(II) spin centers for all complexes are in the high spin state at high temperatures. While the magnetic data of air-dried samples confirm the [HS-HS] state for C1 and C2 down to very low temperature, for C3, a gradual spin crossover is observed below 150 K. The crystal structure of C3·THF at 100 K shows that a spin transition from [HS-HS] to an intermediate state takes place, which is a 1:1 mixture of discrete [HS-HS] and [LS-LS] molecules, as identified unambiguously by crystallography. The different SCO properties of C1–C3 can be attributed to crystal packing effects in the solid state.

scholarly journals Magnetic Properties of Fe(II) Complexes of Cyclam Derivative with One p-Aminobenzyl Pendant Arm

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 366
Author(s):  
Bohuslav Drahoš ◽  
Peter Antal ◽  
Ivan Šalitroš ◽  
Radovan Herchel
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
High Spin ◽  
Spin Crossover ◽  
Crystal Packing ◽  
Theoretical Calculations ◽  
High Spin State ◽  
Magnetic Data ◽  
Pendant Arm ◽  
Pendant Arms

In order to prepare an Fe(II) spin crossover (SCO) complex that could be consequently modified to a bimetallic coordination compound that possesses another magnetic property of interest, a specially designed ligand L-NH2 (1-(4-aminobenzyl)-4,11-bis(pyridine-2-ylmethyl)- 1,4,8,11-tetraazacyclotetradecane) was prepared. This ligand consists of a macrocyclic cyclam part containing two 2-pyridylmethyl pendant arms (expecting SCO upon Fe(II) complexation) and one p-aminobenzyl pendant arm with an NH2 group. The presence of this group enables the consequent transformation to various functional groups for the selective complexation of other transition metals or lanthanides (providing the second property of interest). Furthermore, the performed theoretical calculations (TPSSh/def2-TZVP) predicted SCO behavior for the Fe(II) complex of L-NH2. Thus, Fe(II) complexes [Fe(L-NH2)](ClO4)2 (1) and [Fe(L-NH2)]Cl2·6H2O (2) were synthesized and thoroughly characterized. Based on the crystal structure of an isostructural analogous Ni(II) complex [Ni(L-NH2)]Cl2·6H2O (3), the coordination number six was confirmed with an octahedral coordination sphere and a cis-arrangement of the pyridine pendant arms. The measured magnetic data confirmed the high-spin behavior of both compounds with large magnetic anisotropy (D = 17.8 for 1 and 20.9 cm−1 for 2 complemented in both cases also with large rhombicity), though unfortunately without any indication of the SCO behavior with decreasing temperature. The lack of SCO can be ascribed to the crystal packing and/or the non-covalent intermolecular interactions stabilizing the high-spin state in the solid state.

An X-ray powder diffraction study of the spin-crossover transition and structure of bis(2,6-dipyrazol-1-ylpyrazine)iron(II) perchlorate

2004 ◽  
Vol 60 (1) ◽  
pp. 41-45 ◽  
Author(s):  
Victoria A. Money ◽  
Ivana Radosavljevic Evans ◽  
Jerome Elhaïk ◽  
Malcolm A. Halcrow ◽  
Judith A. K. Howard
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Spin Crossover ◽  
Spin Transition ◽  
High Spin State ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Crossover Transition

The crystal structure of the iron(II) spin-crossover compound [Fe(C10H8N6)2](ClO4)2 in the high-spin state has been solved from powder X-ray diffraction data using the DASH program and refined using Rietveld refinement. The thermal spin transition has been monitored by following the change in unit-cell parameters with temperature. The title compound has been found to undergo a crystallographic phase change, involving a doubling of the crystallographic a axis, on undergoing the spin transition.

4-(Bromomethyl)benzophenone

2007 ◽  
Vol 63 (3) ◽  
pp. o1188-o1189 ◽  
Author(s):  
Wei-Jian Xu ◽  
Yang-Ling Zang ◽  
Guo-Liang Wu ◽  
Sheng-Pei Su ◽  
De-Yue Qiu
Keyword(s):  
Crystal Structure ◽  
Carbon Tetrachloride ◽  
Dihedral Angle ◽  
Structure Analysis ◽  
Title Compound ◽  
Crystal Packing ◽  
Crystal Structure Analysis ◽  
X Ray ◽  
Compound C ◽  
Phenyl Rings

The title compound, C14H11BrO, was synthesized by the reaction of 4-methylbenzophenone and bromine in carbon tetrachloride. X-ray crystal structure analysis reveals that the benzene and phenyl rings form a dihedral angle of 59.53 (6)°, and the crystal packing is stabilized by intermolecular C—H...π interactions.

scholarly journals Preparation of pyridine-3,4-diols, their crystal packing and their use as precursors for palladium-catalyzed cross-coupling reactions

2010 ◽  
Vol 6 ◽  
Author(s):  
Tilman Lechel ◽  
Irene Brüdgam ◽  
Hans-Ulrich Reissig
Keyword(s):  
Crystal Structure ◽  
Crystal Packing ◽  
Cross Coupling ◽  
Crystal Structure Analysis ◽  
Coupling Reactions ◽  
X Ray ◽  
Cross Coupling Reactions ◽  
Fluorescence Measurements ◽  
Subsequent Conversion ◽  
Palladium Catalyzed

A series of trifluoromethyl-substituted 3-alkoxypyridinol derivatives has been deprotected to furnish pyridine-3,4-diol derivatives in good yields. The X-ray crystal structure analysis proved that a 1:1 mixture of pyridine-3,4-diols and their pyridin-4-one tautomers exist in the solid state. Subsequent conversion into bis(perfluoroalkanesulfonate)s were smoothly achieved. The obtained compounds were used as substrates for palladium-catalyzed coupling reactions. Fluorescence measurements of the biscoupled products showed a maximum of emission in the violet region of the spectrum.

scholarly journals Crystal structure analysis of ethyl 6-(4-methoxyphenyl)-1-methyl-4-methylsulfanyl-3-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate

2020 ◽  
Vol 76 (8) ◽  
pp. 1209-1212
Author(s):  
H. Surya Prakash Rao ◽  
Ramalingam Gunasundari ◽  
Jayaraman Muthukumaran
Keyword(s):  
Crystal Structure ◽  
Dihedral Angle ◽  
Structure Analysis ◽  
Title Compound ◽  
Crystal Packing ◽  
Crystal Structure Analysis ◽  
Dihedral Angles ◽  
Pyridine Moiety ◽  
Compound C ◽  
Phenyl Rings

In the title compound, C24H23N3O3S, the dihedral angle between the fused pyrazole and pyridine rings is 1.76 (7)°. The benzene and methoxy phenyl rings make dihedral angles of 44.8 (5) and 63.86 (5)°, respectively, with the pyrazolo[3,4-b] pyridine moiety. An intramolecular short S...O contact [3.215 (2) Å] is observed. The crystal packing features C—H...π interactions.

A fourfold interpenetrating diamond-like three-dimensional zinc(II) coordination polymer: synthesis, crystal structure and physical properties

2019 ◽  
Vol 75 (5) ◽  
pp. 504-507 ◽  
Author(s):  
Hui-Ru Chen
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
Three Dimensional ◽  
Fluorescence Emission ◽  
Crystal Structure Analysis ◽  
The Novel ◽  
X Ray Diffraction ◽  
Metal Compounds ◽  
X Ray ◽  
Coordination Framework

Excellent fluorescence properties are exhibited by d 10 metal compounds. The novel three-dimensional ZnII coordination framework, poly[[{μ2-bis[4-(2-methyl-1H-imidazol-1-yl)phenyl] ether-κ2 N 3:N 3′}(μ2-furan-2,5-dicarboxylato-κ2 O 2:O 5)zinc(II)] 1.76-hydrate], {[Zn(C6H2O5)(C20H18N4O)]·1.76H2O} n , has been prepared and characterized using IR spectroscopy, elemental analysis and single-crystal X-ray diffraction. The crystal structure analysis revealed that the compound exhibits a novel fourfold interpenetrating diamond-like network. This polymer also displays a strong fluorescence emission in the solid state at room temperature.

Crystal Structure and Magnetic Properties of the Novel Hollandite Ba1.3Co1.3Ti6.7O16

2011 ◽  
Vol 66 (11) ◽  
pp. 1097-1100 ◽  
Author(s):  
Larysa Shlyk ◽  
Rainer Niewa
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Single Crystals ◽  
Magnetic Moment ◽  
High Spin State ◽  
The Novel ◽  
Charge Balance ◽  
Vertex Sharing ◽  
State Spin

Single crystals of the new barium hollandite Ba1.3Co1.3Ti6.7O16 were obtained from a BaCl2 flux (I2/m, Z = 1, a = 9.9470(4), b = 2.9714(2), c = 10.2260(5) Å , β = 90.906(2)◦). In the crystal structure piles of Ba atoms are situated within a framework of edge- and vertex-sharing octahedra (Co,Ti)O6. The composition was deduced from microprobe analyses, structure refinements and charge balance arguments in agreement with the observed magnetic properties. The temperature dependence of the magnetic susceptibility χ(T) of Ba1.3Co1.3Ti6.7O16 single crystals reveals paramagnetism down to 2 K. The value of the Co magnetic moment deduced from the Curie-Weiss law agrees well with the theoretical value of the high-spin state spin-only moment of μeff = 3.87 μB for Co2+ (S = 3/2)

X-Ray Crystal Structure Analysis of Deacetyldehydroeuphorianin: The Correct Structure of the Novel Pentacyclic Macrocyclic Diterpene, Euphorianin

1987 ◽  
Vol 42 (2) ◽  
pp. 243-247 ◽  
Author(s):  
Joseph I. Okogun ◽  
Christopher O. Fakunle ◽  
Donald E. U. Ekong ◽  
Hans J. Lindner ◽  
Gerhard G. Habermehl
Keyword(s):  
Crystal Structure ◽  
Structure Analysis ◽  
Crystal Structure Analysis ◽  
The Novel ◽  
X Ray ◽  
Correct Structure

Abstract The conversion of euphorianin to deacetyldehydroeuphorianin which was used in an X-ray crystal structure analysis is described. A new pentacyclic structure related to ingol tetraacetate is described for euphorianin.

An Unusual Hydrogen-Bonded Network Associated with Metal-Organic Chains: Structure and Crystal Packing of the Coordination Polymer [Cd(terephthalate)(H2O)3].4H2O

1998 ◽  
Vol 54 (5) ◽  
pp. 657-662 ◽  
Author(s):  
O. A. Michaelides ◽  
D. Tsaousis ◽  
S. Skoulika ◽  
C. P. Raptopoulou ◽  
A. Terzis
Keyword(s):  
Crystal Structure ◽  
Coordination Polymer ◽  
Single Crystals ◽  
Structure Analysis ◽  
Crystal Packing ◽  
Crystal Structure Analysis ◽  
Water Molecules ◽  
Hexagonal Ice ◽  
Metal Organic ◽  
Hydrogen Bonded

Single crystals of [Cd(terephthalate)(H2O)3].4H2O (1), triaquo(1,4-benzenecarboxylato-κO)cadmium tetrahydrate, are grown in a silica gel column. Crystal structure analysis shows that (1) is a polymer with metal-organic chains stacked along the a axis forming layers parallel to the ab plane. These layers are linked by an unusual hydrogen-bonded network formed by the water molecules (both `free' and coordinated ones) and the carboxylate O atoms. This network comprises tridymite-like O8 cages which `propagate' in the direction of the a axis, mimicking the way they `propagate' along the c axis in hexagonal ice.

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