SYNTHESIS AND ELECTROPHILIC REACTIONS OF LANTHANIDE(III) BETA-DIKETONE SCHIFF-BASE CHELATES

A series of complexes of lanthanides of the general formula [Ln2(ONNO) 3] have been synthesised and their susceptibility to electrophilic sub stitution reactions studied. The schiff base ligands act as dibasic te tradentates, coordinating through deprotonated H-ONNO-H functions. Unl ike the cationic complexes of similar compositions these are reactive. A combined sequence of bromination and phenyl isocyanation on these n eutral diketonates having different alpha- and alpha'-substituents lea d to the formation of different linkage isomeric products characterise d by coordination of either the acetyl carbonyl or the amide carbonyl to the metal.