Di-, tetra- and hexanuclear iron(III), manganese(II/III) and copper(II) complexes of Schiff-base ligands derived from 6-substituted-2-formylphenols?

Dalton Transactions Pub Date: 2009-01-19 DOI: 10.1039/B818113F

Abstract

Acyclic Schiff base ligands, derived from the condensation of 2,3-disubstituted benzaldehydes and 1,3-diaminopropan-2-ol, react with iron(II/III), manganese(II/III) and copper(II) salts to give di-, tetra- and hexanuclear complexes [FeIII2(L5)2]·2MeOH (1), [FeIII4(μ3-OMe)2(HL4)2Cl2] (2), [MnII2MnIII2(μ-OMe)2(HL4)2(DMF)2]·2DMF (3) and [CuII6(L5)2(μ5-SO4)2(μ-SO4)(MeOH)2]·H2O·15.5(MeOH)·15.5(MeCN) (4). All compounds have been characterised by X-ray crystallography. Variable-temperature solid-state dc magnetisation studies have been performed in the temperature range 1.8–300 K. Antiferromagnetic interactions are present in all the compounds. The dinuclear compound 1 has a zero total spin ground state with J = ?9.66(1) cm?1 and g = 2.07(1). The magnetic data for the tetranuclear compounds 2 and 3 have been interpreted using a tetranuclear butterfly model (b = body, w = wingtip) with the parameters: Jwb = ?9.35(4) cm?1, Jbb = ?6.02(7) cm?1, zJ′ = ?0.21(4) cm?1 and g = 2.03(1) for 2; and Jwb = ?3.40(3) cm?1, Jbb = ?8.11(7) cm?1, zJ′ = ?0.042(2) cm?1 and g = 2.0 (fixed) for 3. The hexanuclear compound 4 contains two {Cu3(L5)(MeOH)} units linked by three sulfate ligands: antiferromagnetic interactions are present in each trinuclear unit leading to two S = 1/2 motifs which do not or only very weakly interact across the sulfate bridges.

Graphical abstract: Di-, tetra- and hexanuclear iron(III), manganese(II/III) and copper(II) complexes of Schiff-base ligands derived from 6-substituted-2-formylphenols
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