Synthesis and coordination chemistry of novel binucleating macrocyclic ligands with amine-thioether and amine-thiophenolate donor functions

The ability of the aromatic tetraaldehyde 1,2-bis(4-tert-butyl-2,6-diformyl phenylsulfanyl)ethane (1) to function as a precursor in the preparation of binucleating hexaamine-dithiolate ligands has been investigated. Reductive amination of compound 1 with bis(aminoethyl)amine under medium-dilution con ditions affords the macrobicyclic hexaamine-dithioether compound L-1. Depro tection of the [1+2] condensation product gives the corresponding 24-member ed hexaamine-dithophenol ligand H2L2. The formulation of L as a macrobicycl ic amine-thioether was confirmed by an X-ray crystal structure determinatio n of the tetranuclear nickel(H) complex of L-1, [{(L-1)Ni2Cl2}(2)(mu -Cl)(3 )](BPh4) (2b). The formulation of the doubly deprotonated form (L-2)(2-) of H2L2 as a 24-membered amine-thiophenolate ligand was confirmed by an X-ray crystal structure determination of the dinuclear cobalt(III) complex, [(L- 2)Co-III(mu -OH)](ClO4)(2). Cl ( (3). The preparation and the crystal struc tures of the new compounds are described.