Dimer species in dimethyl sulfoxide–water (80∶20 w/w) solution of N,N′-bis(salicylideneimine)-m-phenylenediamine (H2sal-m-phen) and similar Schiff bases with CuII, NiII, CoII and ZnII. Crystal structure of [Co2(sal-m-phen)2]·CHCl3 ‡
- 1 January 1997
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in J. Chem. Soc., Dalton Trans.
- No. 22,p. 4327-4334
- https://doi.org/10.1039/a702151h
Abstract
Potentiometric studies were carried out in dimethyl sulfoxide–water (80∶20 w/w) at 25 °C and ionic strength 0.1 mol dm–3 in NaClO4 for the Schiff bases H2sal-m-phen [N,N′-bis(salicylidene)-m-phenylenediamine], H2sal-2,4-toluen [N,N′-bis(salicylidene)toluene-2,4-diamine] and H2sal-2,6-toluen [N,N′-bis(salicylidene)toluene-2,6-diamine] and their complexes with CuII, NiII, CoII and ZnII. These studies have shown that monomer, dimer, ligand∶metal ratio 2∶1 and 1∶2 complex species are found. The first reported stability constants for these systems have been determined. The molecular structure of the complex [Co2(sal-m-phen)2]·CHCl3 has been determined by single-crystal X-ray analysis. It consists of dimeric centrosymmetric units, with the two bis(salicylideneiminato)cobalt(II) residues bridged by two m-phenylene groups and with a chloroform molecule associated with each dimer molecule. The co-ordination geometry around each cobalt(II) can be best described as a distorted tetrahedron. Variable-temperature magnetic susceptibility measurements for the solid complexes [Co2(sal-m-phen)2]·CHCl3, [Co2(sal-2,4-toluen)2]·4H2O, [Co2(sal-2,6-toluen)2], [Ni2(sal-m-phen)2]·3H2O, [Ni2(sal-2,4-toluen)2]·3H2O, [Ni2(sal-2,6-toluen)2], [Cu2(sal-2,4-toluen)2] and [Cu2(sal-2,6-toluen)2] revealed a weak intradimer antiferromagnetic interaction.Keywords
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