COMPLEXES WITH MACROCYCLIC LIGANDS .3. MO NONUCLEAR AND DINUCLEAR MACROCYCLIC TRANSITION-METAL COMPLEXES OF LIGANDS OF SCHIFF-BASE TYPE - SYNTHESES, STRUCTURES, ELECTROCHEMICAL AND MAGNETOCHEMICAL PROPERTIES

Four new mononuclear metal(II) complexes (4a-d) of a macrocyclic ligan d derived from the Schiff base condensation of 2 equiv. of 1,2-phenyle nediamine (3a) and 5-tert-butyl-2-hydroxy-1,3-benzenedicarbaldehyde (2 ) were synthesized and the cobalt complex 4b characterized by X-ray st ructure analysis. Reaction of 1,2-diamino-3,4,5,6-tetrafluorobenzene ( 3b) with the dicarbaldehyde 2 in the presence of Mn(ClO4)2 or Co(ClO4) 2 leads to the novel metal-free macrocyce 6 (X-ray structure determina tion). The macrocycle 6 and Cu(ClO4)2 yield the new dinuclear copper c omplex 8, the structure of which was also determined by X-ray diffract ion. The copper-(II) ions in 8 have a distorted square-pyramidal coord ination by the four donor atoms of the macrocycle and an apical aceton itrile ligand. The Cu...Cu distance is 318.1 pm, and the two Cu(II) io ns show only a small antiferromagnetic exchange interaction of J = -41 cm-1. Another new dinuclear Cu(II) complex (10) of a macrocyclic liga nd derived from the Schiff base condensation of 2,2'-diaminooctafluoro biphenyl (9) and dicarbaldehyde 2 was synthesized and characterized by X-ray structure analysis, electrochemical investigations (DCV), and v ariable-temperature magnetic susceptibility measurements. One copper i on in complex 10 is five-coordinate (square-pyramidal), the other one six-coordinate (distorted octahedral). The Cu...Cu distance is 301.5 p m and the antiferromagnetic coupling J = -774 cm-1.