Positioning different metal centers with well-defined electronic environments in a predefined separation and relative orientation so as to achieve the desired bonding interactions still remains an experimental-synthetic challenge. The project primarily focused on the synthesis and characterization of new homo- and hetero-bimetallic complexes containing one and more metal atoms. In these complexes, metal centers are typically bound through bridging ligands, in particular by types of bridging ligands which allow for systematic variation of metal-to-metal distances. Such complexes remain unsatisfactorily characterized and the project proposed to provide insights for a better understanding of their structure-property relations. They are of significant applications interest in the context of magnetic information storage, magnetic refrigeration and optically active materials.
Two main goals for the project were set:
- development of new original synthetic protocols which would allow the obtaining of metal combinations in a way that allows to influence and control their structure;
- finding for unusual magnetic, spectroscopic and optical behaviours by using physical methods that include magnetic susceptibility measurements (d.c. and a.c.) heat capacity measurements, luminescence spectroscopy.
By completing this project, it was proved that by chosing suitable synthetic protocols, salicylaldehyde and its derivatives were able to generate a rich variety of 3d and 3d/4f complexes, both with nuclearity ranging from dinuclear up to tetradecanuclear metallic cores, and one-dimensional coordination networks. The objectives to expand the library of compounds with single-molecule magnet (SMM) behaviour and to better understand the factors that govern magnetic properties were reached. The achieved results are being prepared for publication and the established chemistry of polynuclear complexes will reveal new features and strategies improving their performances as magnetic/luminescent materials and the consequent development of multifunctional molecules.
