Nine self-assembled nickel(ii)–lanthanide(iii) heterometallic complexes constructed from a Salamo-type bisoxime and bearing a N- or O-donor auxiliary ligand: syntheses, structures and magnetic properties

Abstract

Through the self-assembly of a Salamo-type ligand H₂L (H₂L = 1,2-bis(3-methoxysalicylideneaminooxy)ethane) with Ni(OAc)₂·4H₂O, Ln(NO₃)₃·6H₂O (Ln(III) = La(III), Gd(III), Tb(III) and Dy(III)) and Py (Py = pyridine) or 4,4′-bipy (4,4′-bipy = 4,4′-bipyridine) or H₂bdc (H₂bdc = terephthalic acid), nine new Ni(II)–Ln(III) heterometallic complexes [Ni(L)La(OAc)(NO₃)₂(Py)(CH₃OH)]·CH₃OH (1), [Ni(L)Dy(OAc)(NO₃)₂(Py)] (2), ¹_∞[Ni(L)La(NO₃)₃(4,4′-bipy)(CH₃OH)] (3), ¹_∞[Ni(L)Tb(NO₃)₃(4,4′-bipy)] (4), [Ni(L)Dy(OAc)(NO₃)₂(4,4′-bipy)] (5), [{Ni(L)Ln(NO₃)₂(DMF)(CH₃OH)}₂(bdc)] (Ln = La (6) and Gd (7)) and [{Ni(L)Ln(NO₃)₂(DMF)}₂(bdc)] (Ln = Tb (8) and Dy (9)) were obtained, respectively. The acetato ligand bridges the Ni(II) and Ln(III) (Ln = La (1) and Dy (2)) atoms in a μ₂ fashion and the Py coordinates to the apical position by a nitrogen atom in the heterobimetallic complexes 1 and 2. Complexes 3 and 4 are 1D coordination polymers constructed from heterobimetallic [Ni(L)Ln] (Ln = La (3) and Tb (4)) units which are connected by the exo-dentate ligand 4,4′-bipy bearing nitrogen-donor atoms, but complex 5 is a heterobimetallic Ni(II)–Dy(III) complex which is prepared under the same reaction conditions as complexes 3 and 4. Four heterotetranuclear dimers were constructed from heterobimetallic [Ni(L)Ln] (Ln = La (6), Gd (7)), Tb (8) and Dy (9) units which are connected by the exo-dentate H₂bdc ligand with oxygen-donor atoms. Magnetic measurements were performed on the Gd(III), Tb(III) and Dy(III) complexes.