| Abstrakt: |
This paper discusses coordination-position isomeric MCu and CuM complexes, using unsymmetric dinucleating macrocycles (L) ((L), (L) and (L)) that comprise two 2-(N-methyl)-aminomethyl-6-iminomethyl-4-bromo-phenonate entities, combined through the ethylene chain ( m = 2) between the two amine nitrogens and through the ethylene, trimethylene or tetramethylene chain (n = 2, 3 or 4) between the two imine nitrogens. The macrocycles have dissimilar N(amine)O and N(imine)O metal-binding sites sharing the phenolic oxygens. The reaction of the mononuclear Cu precursors, [Cu(L)], [Cu(L)] and [Cu(L)], with a M perchlorate and a M acetate salt formed (acetato)MCu complexes: [CoCu(L)(AcO)]ClO·0.5HO] (1), [NiCu(L) (AcO)]ClO ( 2), [ZnCu(L) (AcO)]ClO ( 3), [CoCu(L)(AcO)]ClO·0.5HO (4), [NiCu(L)(AcO)]ClO ( 5), [ZnCu(L)(AcO)]ClO·0.5HO ( 6), [CoCu(L)(AcO)(DMF)]ClO ( 7), [NiCu(L) (AcO)]ClO·2DMF ( 8) and [ZnCu(L)(AcO)]ClO ( 9) (the formulation [MM (L)] means that M resides in the aminic site and M in the iminic site). The site selectivity of the metal ions is demonstrated by X-ray crystallographic studies for 2·MeOH, 3, 5, 7, and 9. An (acetato)CuZn complex, [CuZn(L)(AcO)]ClO ( 10), was obtained by the reaction of [PbCu(L)]-(ClO) with ZnSO·4HO, in the presence of sodium acetate. Other complexes of the CuM type were thermodynamically unstable to cause a scrambling of metal ions. The Cu migration from the iminic site to the aminic site in the synthesis of 10 is explained by the 'kinetic macrocyclic effect'. The coordination-position isomers, 6 and 10, are differentiated by physicochemical properties. [ABSTRACT FROM AUTHOR] |
