SIZE AND STABILITY OF CHELATE RINGS IN COORDINATION-COMPOUNDS OF COBALT(II), MANGANESE(II), IRON(III) AND PALLADIUM(II) WITH VICINAL OXIME-IMINE LIGANDS

Two types of the CoII complexes L1Co (H2L1=N,N′-ethylenebis(isonitrosoacetylacetoneimine) were prepared. In type (a) the chelate rings are five-membered whereas in type (b) they are six-membered. The type (b) complexes were converted to type (a) in refluxing solutions. Half-ionization of the ligand is observed in the complexes HL1 Co(O2CMe) and HL1MnCl, where the chelate rings are five- and six-membered respectively. The octahedral complex L1FeCl·H2O has chelate rings of type (a) as does the complex L2Co (H2L2=unsymmetric Schiff base N,N′-ethylene(isonitrosoacetylacetoneimineacetylacetoneimine). Two cis complexes (La2Lb3)Pd and (La3)2Pd are characterized (HL3=isonitrosoacetylacetoneimine, (a) and (b) denote the type of chelate ring). Structures for the metal complexes and the sizes of the chelate rings are suggested on the basis of analytical and spectral evidence. © 1990 Chapman and Hall Ltd.