TY  - JOUR
AU  - Ghisolfi, Alessio
AU  - Monakhov, Kirill Yu.
AU  - Pattacini, Roberto
AU  - Braunstein, Pierre
AU  - López, Xavier
AU  - de Graaf, Coen
AU  - Speldrich, Manfred
AU  - van Leusen, Jan
AU  - Schilder, Helmut
AU  - Kögerler, Paul
TI  - A comparative synthetic, magnetic and theoretical study of functional M$_{4}$Cl $_{4}$ cubane-type Co(ii) and Ni(ii) complexes
JO  - Dalton transactions
VL  - 43
IS  - 21
SN  - 1477-9234
CY  - London
PB  - Soc.
M1  - FZJ-2015-04175
SP  - 7847 -
PY  - 2014
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000335926800025
C6  - pmid:24705925
DO  - DOI:10.1039/c4dt00306c
UR  - https://juser.fz-juelich.de/record/201881
ER  -