Tuning nuclearity of clusters by positional change of functional group: Synthesis of polynuclear clusters, crystal structures and magnetic properties

Abstract

Four neutral polynuclear magnetic clusters, [MnIII6MnII2NaI2(N3)8(μ4-O)2(L1)6(CH3OH)2] (1), [MnIII6NaI2(N3)4(μ4-O)2(L2)4(CH3COO)4] (2), [NiII5(N3)4(HL1)4(HCOO)2(CH3OH)2(H2O)2]·2CH3OH (3) and [NiII4NaI2(N3)4(HL2)6]·2CH3OH (4) have been synthesized using tetradentate ligands H2L1-2 along with azide as a co-ligand. H2L1-2 are the products formed in situ upon condensation of 2-hydroxy-3-methoxybenzaldehyde with 1-aminopropan-2-ol and 1-aminopropan-3-ol, respectively. Single crystal X-ray diffraction and bond valence sum calculation showed that complex 1 is composed of both MnIII and MnII. Complex 3 contains coordinated formate, which was formed upon in situ oxidation of methanol. The magnetic study over a wide range of temperatures of all the complexes (1–4) showed that 1 and 2 are antiferromagnetic whereas other two (3–4) are predominantly ferromagnetic. The estimated ground states of the complexes are S ≈ 3(1), S = 4(2), S = 5(3) and S ≈ 4(4), respectively.