Ligand design for multidimensional magnetic materials: a metallosupramolecular perspective

Abstract

The aim and scope of this review is to show the general validity of the 'complex-as-ligand' approach for the rational design of metallosupramolecular assemblies of increasing structural and magnetic complexity. This is illustrated herein on the basis of our recent studies on oxamato complexes with transition metal ions looking for the limits of the research avenue opened by Kahn's pioneering research twenty years ago. The use as building blocks of mono-, di- and trinuclear metal complexes with a novel family of aromatic polyoxamato ligands allowed us to move further in the coordination chemistry-based approach to high-nuclearity coordination compounds and high-dimensionality coordination polymers. In order to do so, we have taken advantage of the new developments of metallosupramolecular chemistry and in particular, of the molecular-programmed self-assembly methods that exploit the coordination preferences of metal ions and specifically tailored ligands. The judicious choice of the oxamato metal building block (substitution pattern and steric requirements of the bridging ligand, as well as the electronic configuration and magnetic anisotropy of the metal ion) allowed us to control the overall structure and magnetic properties of the final multidimensional nD products (n = 0-3). These species exhibit interesting magnetic properties which are brand-new targets in the field of molecular magnetism, such as single-molecule or single-chain magnets, and the well-known class of molecule-based magnets. This unique family of molecule-based magnetic materials expands on the reported examples of nD species with cyanide and related oxalato and dithiooxalato analogues. Moreover, the development of new oxamato metal building blocks with potential photo or redox activity at the aromatic ligand counterpart will provide us with addressable, multifunctional molecular materials for future applications in molecular electronics and nanotechnology.

Design of Magnetic Coordination Polymers Built from Polyoxalamide Ligands: A Thirty Year Story

“…The explanation of these large values for the coupling constant has its origin in the spin-polarization mechanism (Figure 18). [72][73][74] [75] This feature allows the control of the magnetic properties of polynuclear complexes or CPs synthesized with these copper (II 6 ]·6H 2 O} n (2D-CoCumpba) [76] [77] have been solved (Figure 19). Each dicopper(II) metallacyclophane entity acts as a tetrakis(bidentate) ligand through the carbonyl oxygen atoms of the oxamate ligand atoms toward diaquametal(II) units, yielding a brick-wall rectangular layer with a (6,3) net topology.…”

Palladation of diimidazolium salts at the C4 position: access to remarkably electron-rich palladium(ii) centers

“…The behavior of palladium as ligand 24 to silver presumably originates from the strong donor ability of the C4-bound dicarbene ligand.…”

Preparation of New Ligand‐Deficient Thiocyanato Compounds with Cooperative Magnetic Phenomena by Thermal Decomposition of Their Ligand‐Rich Precursors

“…Especially new compounds with interesting magnetic properties, such as cooperative magnetic phenomena, for example, antiferro-or ferromagnetism, are of interest. [2] In this context, we are interested in thermal decomposition reactions of ligand-rich precursor compounds to obtain new ligand-deficient intermediates with interesting magnetic properties. We could prove that thermal decomposition of ligand-rich precursors, which consist of paramagnetic transition metals and not bridging potential magnetic active ligands, leads in most cases to the formation of new ligand-deficient intermediates with a more condensed crystal structure.…”