Electrical, and Magnetic Characteristics of Homo- and Hetero-Bimetallic Macromolecular Complexes with π-Conjugated Imine-oxime Backbone

Abstract

Seven homo- and hetero-bimetallic macromolecular complexes (BMCs) were prepared via an in-situ multi-step complexation reaction of CuII, NiII and FeIII metal centers with imine- oxime π-conjugated ditropic spacer (1,4-phenylene-bis(2,3-butanedeimineoxime, L2−). The structures of the obtained [M-L2-M]x, [M`-L2-M`]x, [M-L2-M`]x and their μ-oxo-[M-L2-Fe]x BMCs (M = CuII, NiII; M` = FeIII) were elucidated using different spectroscopic (UV–Vis, FT-IR), powder X-ray diffraction (p-XRD) and microscopic (SEM) techniques. The SEM images indicate that the obtained BMCs exhibit nano/micro globular and rod-like textures. The electrical and magnetic characteristics of the obtained BMCs can be described as magneto-semiconducting materials. The structural, electrical, and magnetic properties inherited in the prepared regime demonstrate that the examined semiconducting π-spacer has clear ability to semi-conduct electron transport and delocalize spin leading to antiferromagnetic coupling, thus offering a favorable magnetic exchange pathway between the paramagnetic metal sites. However, ferromagnetic enhancement is observed in the μ-oxo-[M-L2-Fe]x BMCs where the μ-oxo-bridge overplays the role of the π-spacer. A magnetic responsive thin film was conveniently obtained by solvent casting of the μ-oxo-[Ni-L2-Fe]x BMC in a transparent poly(methamethylacrylate) matrix.