Template synthesis of macrocyclic dinuclear Cu-II complexes and conversioninto mononuclear complexes by site-selective copper elimination

The acyclic dinucleating ligand, N,N'-dimethyl-N,N'-trimethylenedi-(3-formy l-2-hydroxy-5-methylbenzylamine) (H2L), has been prepared. It combines two Cu-II ions With its N(amine)(2)O-2 and O-4 metal-binding sites to form a di nuclear complex [Cu-2(L)](ClO4)(2). The [1 :1] condensation of [Cu-2(L)](Cl O4)(2) with an aliphatic or aromatic diamine has provided macrocyclic dinuc lear Cu-II complexes [Cu-2(L-i)](ClO4)(2) (L-i = L-1 for the diamine = ethy lenediamine, L-2 for trimethylene-diamine, L-3 for tetramethylenediamine, L -4 for a-phenylenediamine and L-5 for 1,8-diaminonaphthalene). X-ray crysta llographic studies for [Cu-2(L-1)(H2O)](ClO4)(2). MeCN and [Cu-2(L-5)](ClO4 )(2). 2MeOH demonstrate a macrocyclic dinuclear core structure with the two Cu-II ions in the N(amine)(2)O-2 and N(imine)(2)O-2 sites, in the Cu-Cu se paration of ca. 3.0 Angstrom The dinuclear complexes are studied in magneti c, electronic spectral and electrochemical properties. The treatment of the dinuclear complexes with Na2S in acetonitrile resulted in the elimination of one Cu to afford the mononuclear complexes [Cu(L-i)]. xNaClO(4). The X-r ay crystallography for [Cu(L-2)], [Cu(L-3)]. NaClO4 and [Cu(L-4)] has demon strated that the Cu in the N(amine)(2)O-2 site is selectively eliminated. I n the latter complex, the Na-I ion is accommodated in the aminic site.