%0 Journal Article
%A Ghisolfi, Alessio
%A Monakhov, Kirill Yu.
%A Pattacini, Roberto
%A Braunstein, Pierre
%A López, Xavier
%A de Graaf, Coen
%A Speldrich, Manfred
%A van Leusen, Jan
%A Schilder, Helmut
%A Kögerler, Paul
%T A comparative synthetic, magnetic and theoretical study of functional M$_{4}$Cl $_{4}$ cubane-type Co(ii) and Ni(ii) complexes
%J Dalton transactions
%V 43
%N 21
%@ 1477-9234
%C London
%I Soc.
%M FZJ-2015-04175
%P 7847 -
%D 2014
%X We describe the synthesis, structures, and magnetochemistry of new M4Cl4 cubane-type cobalt(II) and nickel(II) complexes with the formula [M(μ3-Cl)Cl(HL·S)]4 (1: M = Co; 2: M = Ni), where HL·S represents a pyridyl-alcohol-type ligand with a thioether functional group, introduced to allow subsequent binding to Au surfaces. Dc and ac magnetic susceptibility data of 1 and 2 were modeled with a full spin Hamiltonian implemented in the computational framework CONDON 2.0. Although both coordination clusters 1 and 2 are isostructural, with each of their transition metal ions in a pseudo-octahedral coordination environment of four Cl atoms and N,O-donor atoms of one chelating HL·S ligand, the substantially different ligand field effects of Co(II) and Ni(II) results in stark differences in their magnetism. In contrast to compound 1 which exhibits a dominant antiferromagnetic intramolecular coupling (J = −0.14 cm−1), 2 is characterised by a ferromagnetic coupling (J = +10.6 cm−1) and is considered to be a single-molecule magnet (SMM), a feature of special interest for future surface deposition studies. An analysis based on density functional theory (DFT) was performed to explore possible magnetostructural correlations in these compounds. Using a two-J model Hamiltonian, it revealed that compound 1 has four positive and two (small) negative JCoCo isotropic interactions leading to a SHS = 6 ground state. Taking into account the magnetic anisotropy, one would recover a MS = 0 ground state since D > 0 from computations. In 2, all the J constants are positive and, in this framework, the zero-field splitting energy characterising the axial anisotropy was estimated to be negative (D = −0.44 cm−1). The computational results are consistent with compound 2 being an SMM.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000335926800025
%$ pmid:24705925
%R 10.1039/c4dt00306c
%U https://juser.fz-juelich.de/record/201881