Two trigonal–bipyramidal cobalt(II) complexes with small magnetic hysteresis: Synthesis, structure and single crystal magnetic studies

Polyhedron ◽  
2013 ◽  
Vol 66 ◽  
pp. 162-166 ◽  
Author(s):  
Ishita Banerjee ◽  
Abhimanyu Jana ◽  
Simranjeet Singh ◽  
Jaromir Marek ◽  
Enrique del Barco ◽  
...  
2019 ◽  
Author(s):  
Tian Han ◽  
Marcus J. Giansiracusa ◽  
Zi-Han Li ◽  
You-Song Ding ◽  
Nicholas F. Chilton ◽  
...  

A dichlorido-bridged dinuclear dysprosium(III) single-molecule magnet [Dy<sub>2</sub>L<sub>2</sub>(<i>µ</i>-Cl)<sub>2</sub>(THF)<sub>2</sub>] has been made using a diamine-bis(phenolate) ligand, H<sub>2</sub>L. Magnetic studies show an energy barrier for magnetization reversal (<i>U</i><sub>eff</sub>) around 1000 K. Exchange-biasing effect is clearly seen in magnetic hysteresis with steps up to 4 K. <i>Ab</i> initio calculations exclude the possibility of pure dipolar origin of this effect leading to the conclusion that super-exchange <i>via</i> the chloride bridging ligands is important.


1982 ◽  
Vol 53 (3) ◽  
pp. 1888-1890 ◽  
Author(s):  
C. P. Landee ◽  
R. D. Willett ◽  
F. Waldner

2020 ◽  
Author(s):  
Viktoria Leonhardt ◽  
Stefanie Fimmel ◽  
Ana-Maria Krause ◽  
Florian Beuerle

<div><div><div><p>A trigonal-bipyramidal covalent organic cage compound serves as an efficient host to form stable 1:1-complexes with C60 and C70. Fullerene encapsulation has been comprehensively studied by NMR and UV/Vis spectroscopy, mass spectrometry as well as single-crystal X-ray diffraction. Exohedral functionalization of encapsulated C60 via threefold Prato reaction revealed high selectivity for the symmetry-matched all-trans-3 addition pattern.</p></div></div></div>


1998 ◽  
Vol 300 (3-4) ◽  
pp. 270-280 ◽  
Author(s):  
K.I. Kugel ◽  
L.G. Mamsurova ◽  
K.S. Pigalskiy ◽  
A.L. Rakhmanov

2004 ◽  
Vol 57 (5) ◽  
pp. 507 ◽  
Author(s):  
Warren A. Grigsby ◽  
Travis S. Morien ◽  
Colin L. Raston ◽  
Brian W. Skelton ◽  
Allan H. White

A single crystal X-ray study shows the product of reaction between quinuclidine, ‘qn’, and tin(IV) chloride in toluene solution to be, unusually, a five-coordinate neutral complex [qnSnCl4]. Sn—N is 2.282(5) Å in an axial site of a trigonal bipyramidal array, trans to an Sn—Cl bond 2.367(2) with Sn—Cl (equatorial) 2.323(2)–2.333(2) Å. With 1,4-pyrazine, ‘pz’, as adumbrated by earlier spectroscopic work, a 1 : 2 (centro-symmetric) adduct, trans-[pz2SnCl4] is obtained (rather than a pyrazine bridged polymer) [Sn—N 2.246(1), Sn—Cl 2.3883(4), 2.3980(4) Å].


2002 ◽  
Vol 57 (10) ◽  
pp. 1090-1100
Author(s):  
Franziska Emmerling ◽  
Caroline Röhr

AbstractThe title compounds were synthesized at a temperature of 700 °C via oxidation of elemental Bi with the hyperoxides AO2 or via reaction of the elemental alkali metals A with Bi2O3. Their crystal structures have been determined by single crystal x-ray diffraction. They are dominated by two possible surroundings of Bi by O, the ψ-trigonal-bipyramidal three (B) and the ψ-tetrahedral four (T) coordination. Cs6Bi4O9 (triclinic, spacegroup P1̄, a = 813.82(12), b = 991.60(14), c = 1213.83(18) pm, α = 103.658(2), β = 93.694(3), γ = 91.662(3)°, Z = 2) contains centrosymmetric chain segmentes [Bi8O18]12- with six three- (T) and two four-coordinated (B) Bi(III) centers. K9Bi5O13 (monoclinic, spacegroup P21/c, a = 1510.98(14), b = 567.59(5), c = 2685.6(2) pm, β = 111.190(2)°, Z = 4) is a mixed valence compound with isolated [BivO4]3- tetrahedra and chains [BiIII4O9]6- of two T and two B coordinated Bi. In the compounds A2Bi4O7 (A = Rb/Cs: monoclinic, C2/c, a = 2037.0(3) / 2130.6(12), b = 1285.5(2) / 1301.9(7), c = 1566.6(2) / 1605.6(9) pm, β = 94.783(3) / 95.725(9)°, Z = 8) ribbons [Bi4O6O2/2]2- are formed, which are condensed to form a three-dimensional framework.


2010 ◽  
Vol 66 (6) ◽  
pp. 585-593 ◽  
Author(s):  
O. Pérez ◽  
S. Malo ◽  
M. Hervieu

Bismuth calcium aluminate, Bi2Ca6Al12O27, has been prepared as a ceramic and a single crystal. Analysis of reciprocal space using both electron and X-ray diffraction show an R-centred hexagonal unit cell: a = b = 17.3892 (4), c = 6.986 (1) Å. Additional weak reflections are observed; they require the introduction of a modulation wavevector q = 0.0453 (2)c* for indexing. The modulated structure has been solved using the superspace formalism [superspace group X\overline{3}(00\gamma)0]. A framework of corner-sharing AlO4 tetrahedra forms corrugated sixfold rings and uncommon triple rings. The Ca2+ cations exhibit an eightfold coordination sphere; edge-sharing CaO8 polyhedra form intertwinned zigzagging rows along c creating a three-dimensional net. Bi atoms are located in large hexagonal tunnels parallel to c and form Bi2O3 pairs, which adopt a trigonal bipyramidal configuration. The 6s 2 lone-electron pairs (Lp) point along c, in the opposite direction to the three Bi—O strong bonds to form two BiO3Lp tetrahedra with a common base. Different orientations of the Bi2O3Lp2 pairs, rotated by 60° around c, are observed. Their stacking modes in each of the hexagonal tunnels are described. The sequence of the stacking varies along c in each of the tunnels.


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