New macrocyclic Cu(II)-bischelates with paddle wheel Cu2-acetate cage

Two novel bolaamphiphile based dicarboxylic ligands L1H(2) and L2H(2) are synthesized by desymmetrizing aromatic anhydrides. The corresponding Cu(II) complexes [ Cu( L1) center dot EtOH](2) (1), [Cu(L2) center dot (CH3CN)](2) (2) are synthesized and characterized. The crystal structure obtained for ( 1) and ( 2) indicates that they are new class of tetralactone type macrocyclic Cu( II) chelate complexes with paddle wheel Cu-2-acetate cage structure. The 1: 1, Cu( II) and ligand ratio leads into formation of a novel binuclear Cu( II) tetracarboxylate complexes. The macrocyclic chelate ring size in compounds 1 and 2 was altered from [15] membered to [19] membered by introducing phthalyl and diphenyl head groups as discussed in detail. The single crystal X-ray structure shows the Cu(II) center dot center dot center dot Cu(II) distance 2.613(13) A for 1 and 2.626( 13) angstrom for 2, the corresponding room temperature EPR spectra recorded for powdered polycrystalline samples indicate the existence of Cu( II) center dot center dot center dot Cu( II) dimeric system. (c) 2007 Elsevier B. V. All rights reserved.