Template synthesis of macrocyclic dinuclear CuII complexes and conversion into mononuclear complexes by site-selective copper elimination

The acyclic dinucleating ligand, N,N'-dimethyl-N,N'-trimethylenedi-(3-formyl-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 dinuclear complex [Cu-2(L)](ClO4)(2). The [1 :1] condensation of [Cu-2(L)](ClO4)(2) with an aliphatic or aromatic diamine has provided macrocyclic dinuclear Cu-II complexes [Cu-2(L-i)](ClO4)(2) (L-i = L-1 for the diamine = ethylenediamine, L-2 for trimethylene-diamine, L-3 for tetramethylenediamine, L-4 for a-phenylenediamine and L-5 for 1,8-diaminonaphthalene). X-ray crystallographic 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 separation of ca. 3.0 Angstrom The dinuclear complexes are studied in magnetic, 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-ray crystallography for [Cu(L-2)], [Cu(L-3)]. NaClO4 and [Cu(L-4)] has demonstrated that the Cu in the N(amine)(2)O-2 site is selectively eliminated. In the latter complex, the Na-I ion is accommodated in the aminic site.