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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

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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
 
Creator HAZRA, S
BHATTACHARYA, S
SINGH, MK
CARRELLA, L
RENTSCHLER, E
WEYHERMUELLER, T
RAJARAMAN, G
MOHANTA, S
 
Subject SINGLE-MOLECULE MAGNET
TRANSITION-METAL-COMPLEXES
GAUSSIAN-BASIS SETS
SPIN GROUND-STATE
EXCHANGE INTERACTIONS
LANTHANIDE COMPLEXES
THEORETICAL EXPLORATION
COORDINATION CLUSTERS
COPPER(II) COMPLEXES
ANISOTROPY BARRIER
 
Description 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.
 
Publisher AMER CHEMICAL SOC
 
Date 2014-10-16T13:00:13Z
2014-10-16T13:00:13Z
2013
 
Type Article
 
Identifier INORGANIC CHEMISTRY, 52(22)12881-12892
0020-1669
1520-510X
http://dx.doi.org/10.1021/ic400345w
http://dspace.library.iitb.ac.in/jspui/handle/100/15610
 
Language en