The synthesis, crystallographic and magnetic characterization of di- and tri-nuclear Ni(II) and Co(II) complexes of (2-sulfanylphenyl)bis(pyrazolyl)methane
- 1 January 1999
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in J. Chem. Soc., Dalton Trans.
- No. 5,p. 807-814
- https://doi.org/10.1039/a808164f
Abstract
The synthesis of a trinuclear thiolate bridged NiII system, [Ni3(L5S)4]2+ [L5SH = (2-sulfanylphenyl)bis(pyrazolyl)methane] which contains a linear NiS2NiS2Ni moiety, is reported. Two octahedrally coordinated (L5S)2Ni complexes, in which the thiol sulfurs are mutually cis, constitute the two terminal positions while the central position contains a distorted tetrahedral, four-coordinate, Ni(II) ion. In the presence of alkyl- or aryl-nitriles, such as MeCN, the [Ni3(L5S)4]2+ cation undergoes cleavage and rearrangement reactions to give thiolate bridged dinuclear dications, either [Ni2(L5S)2(MeCN)4]2+ or [Ni2(L5S)2(MeCN)2(H2O)2]2+, in which MeCN ligand N-donors (and/or H2O O-donors) occupy the vacant coordination sites of each Ni2+ atom. An analogous Co(II) dimer is also reported. The trimer → dimer reaction can be reversed by desolvation of [Ni2(L5S)2(MeCN)4]2+ or [Ni2(L5S)2(MeCN)2(H2O)2]2+ by an appropriate non-nitrile solvent, such as MeNO2 resulting in reformation of the [Ni3(L5S)4]2+ cation. Variable temperature magnetic data indicate that the Ni atoms in the trimer are weakly antiferromagnetically coupled while they are weakly ferromagnetically coupled in the dimer.Keywords
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