Lanthanide-based sandwich complexes

Figure 7.1 Lanthanide-based sandwich complexes for generation of syndiotactically enriched polystyrene.

Pushkarev VE, Tolbin AY, Zhurkin EE, Borisova NE, Trashin SA, Tomilova LG et al (2012) Sandwich double-decker lanthanide(III) Intracavity Complexes based on clamshell-type phthalocyanine ligands synthesis, spectral, electrochemical, and spectroelectrochemical investigations. Chem Eur J 18(29) 9046-9055... 

Shell structure, relativistic and electron correlation effects play an important role for the electronic structure of lanthanide and actinide systems. The importance and the magnitude of these effects have been examplified for the atoms Ce and Th, and the contributions of the Ce 4f and Th 5f shell to chemical bonding have been reviewed for the monoxides CeO and ThO, respectively. Currently quantitatively correct results for lanthanides and actinides can only be obtained from ab initio calculations for the easiest cases, e.g., small systems (atoms, diatomics containing one f element) with a possibly small number of unpaired f electrons and/or problems related only to configurations with the same f occupation number. In other cases ab initio quantum chemistry can at least help to interprete experimental findings. As an example organometallic cerium sandwich complexes such as cerocene were discussed, which may be considered to be molecular analogues of cerium(in)-based Kondo lattice systems. 

Multidecker lanthanide complexes (1-5) have been synthesized from the reactions of lanthanide salts with conjugated Schiff-base ligands H2L . An interesting emerging feature exhibited by these complexes is the self-assembly of stacked multidecker stmctures in which Ln ions are sandwiched between alternating layers of the Schiff-base ligands. 

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