Dinuclear and heptanuclear nickel(II) complexes: Anion coordination induced ligand arm hydrolysis and aggregation around a nickel(II) core

The heptanuclear and tetracationic nickel(II) complex [Ni7(μ3-OH)6(μ3-H2L)4](NO3)4·2MeOH (3·2MeOH); (H3L is 2,6-bis-[(3-hydroxy-propylimino)-methyl]-4-methyl-phenol), featuring four defective cubanes around a pivotal nickel(II) ion, has been obtained via hydroxido-bridge-induced assemblage of two Ni3 fragments. Presence of azido (N3−) and bromido (Br−) ions in reactions on the contrary lead to one ligand imine arm hydrolysis and formations of [Ni2(N3)2(μ-HL1)2(OH2)2] (1) and [Ni2Br2(μ-HL1)2(OH2)2] (2); where H2L1 is 2-hydroxy-3-[(3-hydroxy-propylimino)-methyl]-5-methyl-benzaldehyde. X-ray structural analyses of 3 show six symmetrically positioned NiII around a central NiII and bridged by six in situ generated hydroxido groups from solvent water molecules. Density functional theory (DFT) calculations have also been performed to predict magnetic behavior of the complexes. The spin density surface of compounds 1 and 2 has been also obtained.

Water derived in situ generation of hydroxido anions lead to self-assembly of four phenoxido-based Schiff base ligated [Ni2] fragments around a central NiII cation providing a novel heptanuclear nickel(II) complex.Figure optionsDownload as PowerPoint slide