SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF METAL-COMPLEXES OF AN UNSYMMETRIC N3O TETRADENTATE SCHIFF-BASE LIGAND

The nickel(II) and copper(II) complexes of the unsymmetrical N3O tetra dentate Schiff base ligand, H-2-ambprsal, which is the 1:1:1 condensat ion product of 2-aminobenzaldehyde (amb), 1,3-diaminopropane (pr) and salicylaldehyde (sai), were prepared by the reaction of HsalprNH(2) (H salprNH(2) is the 1:1 monocondensate of salicylaldehyde with 1,3-diami nopropane) with 2-aminobenzaldehyde, metal nitrate and triethylamine i n methanol. Replacement of the nickel in Ni(ambprsal) with FeCl was ac complished by reaction of Ni(ambprsal) with dimethylglyoxime in benzen e followed by reaction with iron(III) chloride. Structural investigati on was carried out on the nickel(II) and copper(II) complexes. Both Ni (ambprsal) and Cu(ambprsal) are monomeric and approximately square pla nar. The six-membered ring containing the metal, the azomethine nitrog en atoms and the three carbons of the 1,3 diaminopropane bridge adopt the symmetrical boat conformation with the metal and the central carbo n atoms occupying the bow and stern positions. The conformation of the ligand and the N3O donor set may both contribute to the high spin sta te of the iron atom in Fe(ambprsal) Cl. (C) 1998 Elsevier Science S,A. All rights reserved.