Structural determinations of homo and heterodi- or tetra-nuclear lanthanide complexes and their characterization by μ-Squid experiments

Two families of homo- and heterodinuclear complexes are prepared and structurally characterized, thus demonstrating that genuine complexes involving two lanthanide ions closely located in the lanthanide series can be obtained, taking into account a simple rule that necessitates introduction of the better Lewis acid Ln ion (the smallest Ln ion) into the inner coordination site of the main ligand used in this synthesis. In the first family, the presence of a deprotonated orthovanillin ligand (ovan) around the Ln ion positioned in the outer coordination site of the main ligand allows a good isolation of the dinuclear complexes. These complexes behave as SMSs when a Dy ion is coordinated in the outer site but a weak magnetic magnetic Ln-Dy interaction is needed to create a weak magnetic field able to suppress collapsing of the hysteresis loops in zero external applied field at very low temperature. In the second family, the ovan ligand is replaced by a chloride ligand, so that two dinuclear units are linked together by two Cl...HOMe hydrogen bonds to yield tetranuclear complexes that are not SMMs. Eventually these two preparation pathways are expected to give novel and genuine examples of homo or heterodinuclear and tetranuclear lanthanide complexes likely to furnish in future coordination complexes useful in quantum computing.