Please use this identifier to cite or link to this item: http://dspace.library.iitb.ac.in/xmlui/handle/100/16022
Title: From antiferromagnetic to ferromagnetic exchange in a family of oxime-based Mn-III dimers: a magneto-structural study
Authors: BARROS, WP
INGLIS, R
NICHOL, GS
RAJESHKUMAR, T
RAJARAMAN, G
PILIGKOS, S
STUMPF, HO
BRECHIN, EK
Issue Date: 2013
Publisher: ROYAL SOC CHEMISTRY
Citation: DALTON TRANSACTIONS, 42(47)16510-16517
Abstract: The reaction of Mn(ClO4)(2)center dot 6H(2)O, a derivatised phenolic oxime (R-saoH(2)) and the ligand tris(2-pyridylmethyl)amine (tpa) in a basic alcoholic solution leads to the formation of a family of cluster compounds of general formula [(Mn2O)-O-III(R-sao)(tpa)(2)](ClO4)(2) (1, R = H; 2, R = Me; 3, R = Et; 4, R = Ph). The structure is that of a simple, albeit asymmetric, dimer of two Mn-III ions bridged through one mu-O2- ion and the -N-O- moiety of the phenolic oxime. Magnetometry reveals that the exchange interaction between the two MnIII ions in complexes 1, 3 and 4 is antiferromagnetic, but that for complex 2 is ferromagnetic. A theoretically developed magneto-structural correlation reveals that the dominant structural parameter influencing the sign and magnitude of the pairwise interaction is the dihedral Mn-O-N-Mn (torsion) angle. A linear correlation is found, with the magnitude of J varying significantly as the dihedral angle is altered. As the torsion angle increases the AF exchange decreases, matching the experimentally determined data. DFT calculations reveal that the (dyz)vertical bar pi vertical bar d(yz) interaction decreases as the dihedral angle increases leading to ferromagnetic coupling at larger angles.
URI: http://dx.doi.org/10.1039/c3dt52009a
http://dspace.library.iitb.ac.in/jspui/handle/100/16022
ISSN: 1477-9226
1477-9234
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