Lanthanide complexes conjugated Schiff-base ligands

Polynuclear Lanthanide Complexes with Conjugated Schiff-Base Ligands 282... 

POLYNUCLEAR LANTHANIDE COMPLEXES WITH CONJUGATED SCHIFF-BASE LIGANDS... 

Recently, the use of pthalocyanines and porphyrins by Ishikawa and coworkers enabled tiie synthesis of several so-called double-decker or triple-decker lanthanide complexes, described as stacked Ji-conjugate molecules. The photophysical properties of lantiianide ious depeud markedly on their coordination environments. Since a multidecker framework can effectively keep solvent molecules away from Ln centers, it is assumed that enhanced luminescent properties can be achieved witii these types of architectures. We discovered that the use of two conjugated Schiff-base ligands H2Lh can stabihze novel multidecker framewoiks (Scheme 1). 

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. 

Two kinds of salen-type Schiff-base ligands, conjugated and flexible, have been used in the synthesis of polynuclear lanthanide complexes and lanthanide coordination polymers Lanthanides Coordination Chemistry, Rare Earth Metal Cluster Complexes. The stoichiometry and structures of these complexes are dependent on the Schiff-base... 

---