Structural and Magnetic Studies of a Quasi-Inverse Sandwich Cyclooctatetraene Complex with Two High-Spin Chromium(II) Ions Bound Anti-Facially

2012 ◽  
Vol 31 (24) ◽  
pp. 8556-8560 ◽  
Author(s):  
Jessica N. Boynton ◽  
Owen T. Summerscales ◽  
Fernande Grandjean ◽  
Gary J. Long ◽  
James C. Fettinger ◽  
...  
Keyword(s):  
2014 ◽  
Vol 67 (11) ◽  
pp. 1574 ◽  
Author(s):  
Darunee Sertphon ◽  
David J. Harding ◽  
Phimphaka Harding ◽  
Keith S. Murray ◽  
Boujemaa Moubaraki ◽  
...  

A new sterically bulky Schiff base ligand, N-(8-quinolyl)-5-tert-butylsalicylaldimine (Hqsal-5-tBu) has been prepared and a series of FeIII complexes, [Fe(qsal-5-tBu)2]Y (Y = Cl 1, ClO4 2, NO3 3, BF4 4) utilising this ligand are reported and fully characterised. UV-vis spectroscopic and electrochemical studies indicate that 1–4 are high spin (HS) in solution at room temperature and further suggest that the tBu group only slightly alters the electronic properties of 1–4 compared with related [Fe(qsal-5-X)2]+ systems. The structures of [Fe(qsal-5-tBu)2]Cl·4MeOH·H2O 1, [Fe(qsal-5-tBu)2]ClO4·MeOH 2, and [Fe(qsal-5-tBu)2]NO3 3 determined at 100 K reveal HS FeIII centres in all cases. Four-fold parallel aryl embraces and π–π interactions serve to link the cations forming 2D sheets mirroring the motifs found in other [Fe(qsal-5-X)2]+ complexes. Despite this the tBu group causes strong distortions at the Fe centre which as magnetic studies reveal prevent spin crossover trapping 1–4 in the HS state.


1961 ◽  
Vol 83 (20) ◽  
pp. 4157-4161 ◽  
Author(s):  
F. A. Cotton ◽  
D. M. L. Goodgame ◽  
M. Goodgame ◽  
A. Sacco

Molecules ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 251 ◽  
Author(s):  
Michal Liberka ◽  
Jedrzej Kobylarczyk ◽  
Robert Podgajny

The combinations of Co(II), octacyanidotungstate(V), and monodentate pyridine N-oxide (pyNO) or 4-phenylpyridine N-oxide (4-phpyNO) led to crystallization of novel crystalline phases {CoII[CoII8(pyNO)12(MeOH)12][WV(CN)8]6} (1) and {CoII[CoII8(4-phpyNO)7(MeOH)17][WV(CN)8]6}·7MeOH·(4-phpyNO)3 (2). In both architectures, metal–cyanide clusters are coordinated by N-oxide ligands in a simple monodentate manner to give the spherical objects of over 1 nm core diameter and about 2.2 nm (1) and 3 nm (2) of the total diameter, terminated with the aromatic rings. The supramolecular architecture is dominated by dense and rich π–π interaction systems. Both structures are characterized by a significant structural disorder in ligand shell, described with the suitable probability models. For 1, the π–π interactions between the pyNO ligands attached to the same metal centers are suggested for the first time. In 2, 4-phpyNO acts as monodentate ligand and as the crystallization molecule. Magnetic studies indicate the high-spin ground state due to the ferromagnetic interactions Co(II)–W(V) through the cyanido bridges. Due to the high symmetry of the clusters, no signature of slow magnetic relaxation was observed. The characterization is completed by solid-state IR and UV–Vis–NIR spectroscopy. The conditions for the stable M9M’6-based crystals formation are synthetically discussed in terms of the type of capping ligands: monodentate, bridging, and chelating. The potential of the related polynuclear forms toward the magnetism-based functional properties is critically indicated.


Crystals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 401 ◽  
Author(s):  
Taous Houari ◽  
Emmelyne Cuza ◽  
Dawid Pinkowicz ◽  
Mathieu Marchivie ◽  
Said Yefsah ◽  
...  

We present here a new series of spin crossover (SCO) Fe(II) complexes based on dipyridyl-N-alkylamine and thiocyanate ligands, with the chemical formulae [Fe(dpea)2(NCS)2] (1) (dpea = 2,2’-dipyridyl-N-ethylamine), I-[Fe(dppa)2(NCS)2], (2) II-[Fe(dppa)2(NCS)2], and (2’) (dppa = 2,2’-dipyridyl-N-propylamine). The three complexes displayed nearly identical discrete molecular structures, where two chelating ligands (dpea (1) and dppa (2 and 2’)) stand in the cis-positions, and two thiocyanato-κN ligands complete the coordination sphere in the two remaining cis-positions. Magnetic studies as a function of temperature revealed the presence of a complete high-spin (HS) to low-spin (LS) transition at T1/2 = 229 K for 1, while the two polymorphs I-[Fe(dppa)2(NCS)2] (2) and II-[Fe(dppa)2(NCS)2] (2’) displayed similar magnetic behaviors with lower transition temperatures (T1/2 = 211 K for 2; 212 K for 2’). Intermolecular contacts in the three complexes indicated the absence of any significant interaction, in agreement with the gradual SCO behaviors revealed by the magnetic data. The higher transition temperature observed for complex 1 agrees well with the more pronounced linearity of the Fe–N–C angles recently evidenced by experimental and theoretical magnetostructural studies.


2015 ◽  
Vol 6 (12) ◽  
pp. 6823-6828 ◽  
Author(s):  
Katie E. R. Marriott ◽  
Lakshmi Bhaskaran ◽  
Claire Wilson ◽  
Marisa Medarde ◽  
Stefan T. Ochsenbein ◽  
...  

High-field EPR and magnetic studies of a high-spin Ni(ii) trigonal bipyramidal complex reveal a giant axial magnetic anisotropy and a rare field-induced slow magnetic relaxation.


1982 ◽  
Vol 37 (7) ◽  
pp. 832-837 ◽  
Author(s):  
W.-D. Griebler ◽  
D. Babel

Abstract The perovskite-related cyano compounds CsMIICr(CN)6 (MII = Mn, Zn), CsZnFe(CN)6 and CsMnCo(CN)6 (Mn = Mn-Cu) are characterized by their IR active C - N and MIII-CN stretching frequencies, their lattice constants and their magnetic susceptibilities (4,2-295 K). Except for CsCuCo(CN)6, which is tetragonally distorted, all compounds crystallize cubically face-centered (with lattice constants in the range from 1020 to 1084 pm). The magnetic behaviour indicates low spin MIII and high spin MII states, supporting the IR evidence for a strictly ordered MIII-CN-MII arrangement. The compound CsMnCr(CN)6 is ferrimagnetic, with a Néel temperature of TN = 90 K and an extrapolated spontaneous magnetization of a = 2,30 μB at 0 K. Superexchange interactions via the cyano bridges are considered responsible for the ferrimagnetism observed.


2004 ◽  
Vol 114 ◽  
pp. 645-647
Author(s):  
S. Sharmin ◽  
A. Ardavan ◽  
S. J. Blundell ◽  
A. I. Coldea ◽  
E. J.L. McInnes ◽  
...  

2000 ◽  
Vol 80 (2) ◽  
pp. 155-163 ◽  
Author(s):  
S. Odin, F. Baudelet, E. Dartyge, J. P

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