Probing through-space and through-bond magnetic exchange couplings in a new benzotriazinyl radical and its metal complexes

2019 ◽  
Vol 48 (37) ◽  
pp. 14189-14200 ◽  
Author(s):  
Rajendar Nasani ◽  
Thulaseedharan Nair Sailaja Sidharth ◽  
Subhadip Roy ◽  
Arpan Mondal ◽  
Jeremy M. Rawson ◽  
...  
Keyword(s):  
Metal Complexes ◽  
Exchange Coupling ◽  
Ferromagnetic Metal ◽  
Antiferromagnetic Exchange ◽  
Magnetic Exchange ◽  
Radical Coupling ◽  
Metal Radical

A new Blatter radical and its Zn(ii) (1), Ni(ii) (2) and Co(ii) (3) complexes were isolated. Complex 1 exhibited radical⋯radical antiferromagnetic exchange coupling, whereas complexes 2 and 3 showed ferromagnetic metal–radical coupling.

scholarly journals Exploring through-bond and through-space magnetic communication in 1,3,2-dithiazolyl radical complexes

2019 ◽  
Vol 55 (66) ◽  
pp. 9849-9852
Author(s):  
Dominique Leckie ◽  
Nadia T. Stephaniuk ◽  
Ana Arauzo ◽  
Javier Campo ◽  
Jeremy M. Rawson
Keyword(s):  
Exchange Coupling ◽  
Molecular Packing ◽  
Magnetic Exchange ◽  
Metal Radical

Coordination of the dithiazolyl radical MBDTA leads to strong intramolecular metal–radical magnetic exchange but the strength of the intermolecular exchange coupling is strongly dependent on molecular packing.

Metal pyrazolate polymers. Part 2. Synthesis, structure, and magnetic properties of [Cu(4-Xpz)2]x polymers (where X = Cl, Br, Me, H; pz = pyrazolate)

1991 ◽  
Vol 69 (3) ◽  
pp. 432-439 ◽  
Author(s):  
Martin K. Ehlert ◽  
Steven J. Rettig ◽  
Alan Storr ◽  
Robert C. Thompson ◽  
James Trotter
Keyword(s):  
Exchange Coupling ◽  
Structural Parameters ◽  
Magnetic Data ◽  
Antiferromagnetic Exchange ◽  
Coupling Constant ◽  
Orthorhombic Space Group ◽  
Magnetic Exchange ◽  
Linear Chains ◽  
Green Form ◽  
Reliable Methods

Novel and reliable methods for the synthesis of the polymers [Cu(4-Xpz)2]x (where X = H, Cl, Br, and Me; pz = pyrazolate) are presented. The X = Cl compound was obtained as green and brown forms. Single crystals of the polymers with X = Me and X = Cl (green form) suitable for X-ray analysis have been obtained. [Cu(4-Mepz)2]x and [Cu(4-Clpz)2]x are isomorphous, crystallizing with four formula units per unit-cell in the orthorhombic space group Ibam, a = 9.7436(6), 9.155(4), b = 12.6106(8), 12.968(6), and c = 7.7482(6), 7.717(5) Å, respectively, for the 4-Me and 4-Cl derivatives. The structures were refined by full-matrix least-squares procedures to R = 0.027 and 0.041 for 430 and 246 reflections with I ≥ 3σ(I), respectively. Magnetic susceptibility studies over the temperature range 2 to 300 K have revealed that all the polymers exhibit very strong antiferromagnetic exchange between copper(II) centres in the extended linear chains. Discontinuities displayed in the susceptibility versus temperature plots suggest the presence of phase transitions at ~133 and ~108 K in the X = Cl (green form) and X = Br materials, respectively. The four compounds, X = H, Br, Me, and Cl (green form) also exhibit thermochromism over the 77 to 176 K region. The magnetic data have been analyzed employing an isotropic Heisenberg model for antiferromagnetic exchange in extended chain polymers. Values of the exchange coupling constant, J, for the room temperature forms of these materials are determined as −81, −105, −96, −104, and −88 cm−1 for 4-X = H, Br, Me, Cl (green form), and Cl (brown form), respectively. The magnitude of the exchange coupling is discussed in relation to structural parameters for the X = H, Me, and Cl (green form) compounds. Key words: copper(II) 4-substituted pyrazolate polymers, crystal structures, magnetic exchange.

Probing the strong magnetic exchange behaviour of transition metal–radical complexes: a DFT case study

2020 ◽  
Vol 49 (14) ◽  
pp. 4539-4548 ◽  
Author(s):  
Mukesh Kumar Singh
Keyword(s):  
Transition Metal ◽  
Exchange Coupling ◽  
Structural Parameters ◽  
Fine Tuning ◽  
Magnetic Exchange ◽  
Magnetic Exchange Coupling ◽  
Exchange Behaviour ◽  
Metal Radical ◽  
The Way

Alteration of the structural parameters of metal–radical complexes may pave the way forward for fine tuning the magnetic exchange coupling value as high as >−500 cm−1 – a much sought-after parameter in the area of SMMs.

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