Metallosupramolecular approach toward multifunctional magnetic devices for molecular spintronics

The work presented in this review constitutes a successful extension of our group’s research on the chemistry and physics of dinuclear copper(II) metallacyclophanes with aromatic polyoxalamide ligands. The design and synthesis of metallacyclic complexes that contain multiple electro- and photoactive (eithermetal- or ligand-based) spin carriers and the study of their spectroscopic and magnetic properties as wellas their redox and photochemical activity are of large interest in the multidisciplinary field of metallosupramolecularchemistry. In doing this, a ligand design approach has been followed which is based on the copper(II)-mediated self-assembly of bis(oxamato) bridging ligands possessing potentially electro- andphotoactive, extended p-conjugated aromatic spacers. This strategy benefits from the inherent physical and chemical properties of aromatic organic molecules by functionalizing them with two oxamato donor groups to get dinucleating ligands that are then able to self-assemble with square planar CuII ions affording the targeted oxamato-based dicopper(II) metallacyclophanes. The organic functionalization in this new class of metallacyclic systems constitutes a unique example of ligand design for the supramolecular control of the structure and magnetic properties, as well as the electro- and photochemical activities. This novel class of oxamato-based dicopper(II) metallacyclophanes provides excellent models for thefundamental study on through-ligand long-distance and redox- or photo-triggered electron Exchange phenomena, which are two central topics in molecular magnetism and molecular electronics. Using these simple dinuclear metallacyclic complexes as dynamic chemical systems to perform specific and selectivetasks under the control of an external (electro- and/or photochemical) stimulus that switches “ON” and “OFF” their electronic (optical and/or magnetic) properties may have an enormous impact in severaldomains of molecular nanoscience. Hence, oxamato-based dicopper(II) metallacyclophanes appear asvery promising candidates to get multifunctional magnetic devices controlling and facilitating the spincommunication (“molecular magnetic couplers” and “molecular magnetic wires”) or exhibiting chargestorage (“molecular magnetic capacitors”) and bistable spin behavior (“molecular magnetic rectifiers” and “molecular magnetic switches”) for potential applications in information processing and storage inthe emerging areas of molecular spintronics and quantum computing. Moreover, because of the potentialhigh affinity for a variety of metal surfaces through the free carbonyl-oxygen atoms of the oxamate groups, they are very appealing candidates for the study of coherent electron transport through single molecules.