Publication Type Journal Article
Title Syntheses, Structures, Magnetic Properties, and Density Functional Theory Magneto-Structural Correlations of Bis(mu-phenoxo) and Bis(mu-phenoxo)-mu-acetate/Bis(mu-phenoxo)-bis(mu-acetate) Dinuclear (FeNiII)-Ni-III Compounds
Authors Susanta Hazra Sagarika Bhattacharya Mukesh Kumar Singh Luca Carrella Eva Rentschler Thomas Weyhermueller Gopalan Rajaraman Sasankasekhar Mohanta
Groups
Journal INORGANIC CHEMISTRY
Year 2013
Month November
Volume 52
Number 22
Pages 12881-12892
Abstract The bis(mu-phenoxo) (FeNiIII)-Ni-II compound [Fe-III(N-3)(2)LNiII(H2O)(CH3CN)](ClO4) (1) and the bis(mu-phenoxo)-mu-acetate/bis(mu-phenoxo)-bis(mu-acetate) (FeNiII)-Ni-III compound \[Fe-III(OAc)LNiII(H2O)(mu-OAc)](0.6)center dot[(FeLNiII)-L-III(mu-OAc)(2)](0.4)\(ClO4)center dot 1.1H(2)O (2) have been synthesized from the Robson type tetraiminodiphenol macrocyclic ligand H2L, which is the [2 + 2] condensation product of 4-methyl-2,6-diformylphenol and 2,2 -dimethy1-1,3-diaminopropane. Single-crystal X-ray structures of both compounds have been determined. The cationic part of the dinuclear compound 2 is a cocrystal of the two species [Fe-III(OAc)LNiII(H2O)(mu-OAc)](+) (2A) and [(FeLNiII)-L-III(mu-OAc)(2)](+) (2B) with weights of 60\% of the former and 40\% of the latter. While 2A is a triply bridged bis(mu-phenoxo)-mu-acetate system, 2B is a quadruply bridged bis(mu-phenoxo)-bis(mu-acetate) system. Variable-temperature (2-300 K) magnetic studies reveal antiferromagnetic interaction in 1 and ferromagnetic interaction in 2 with J values of -3.14 and 7.36 cm(-1), respectively (H = -2JS(1)center dot S-2). Broken-symmetry density functional calculations of exchange interaction have been performed on complexes 1 and 2 and also on previously published related compounds, providing good numerical estimates of J values in comparison to experiments. The electronic origin of the difference in magnetic behavior of 1 and 2 has been well understood from MO analyses and computed overlap integrals of BS empty orbitals. The role of acetate and thus its complementarity/countercomplementarity effect on the magnetic properties of diphenoxo-bridged (FeNiII)-Ni-III compounds have been determined on computing J values of model compounds by replacing bridging acetate and nonbridging acetate ligand(s) by water ligands in the model compounds derived from 2A,B. The DFT calculations have also been extended to develop several magneto-structural correlations in these types of complexes, and the correlations focus on the role of Fe-O-Ni bridge angle, average Fe/Ni-O bridge distance, Fe-O-Ni-O dihedral angle, and out-of-plane shift of the phenoxo group.
DOI http://dx.doi.org/10.1021/ic400345w
ISBN
Publisher
Book Title
ISSN 0020-1669
EISSN 1520-510X
Conference Name
Bibtex ID ISI:000327225900009
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