Coordination chemistry of thiaoxa-and thiaoxaaza-macrocycles is an intensive area of investigation, and a number of related macrocycles and their soft and heavy metal ion complexes are reported. 1 These macrocycles show the remarkable ability to form stable complexes with d-block metal ions, in many cases forcing the metal ion to adopt unusual position. In particular, the versatility of sulfurcontaining macrocycles makes them useful for a range of d 10 -metal complexes as products because the

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... lfur donor is expected to favor binding toward soft metals such as silver(I), copper(I) and mercury(II) in either exo-2 or endocyclic mode. Some complexes with the exocyclic mode have been investigated by us 3 and others. 4 Recently, we have reported the fact that the influence of the ring rigidity of the small thiaoxa-macrocycles in complexation alters the ligand behavior and has important consequences for ligand bonding. 3a As a part of ongoing efforts, we herein report our investigation of mercury(II) and copper(I) complexes for the medium or larger macrocycles (L 1 and L 2 ) with sulfur donors and aromatic-subunits simultaneously exhibiting different coordination modes and topologies. Results and Discussion Synthesis of Macrocyclic Ligands. The bimolecular cyclization of dichloride-dithiol enables the preparation of dithia-macrocycles via C-S bond formation. 5 Thus, L 1 was synthesized by coupling reaction between dichloride (6) and 1,2-ethanedithiol in the presence of Cs 2 CO 3 in moderate yield (20%) (Figure 1 ). L 2 was prepared with the method reported by us previously. 6 Compounds 4-6 were prepared using known procedures. 7 The 1 H and 13 C NMR spectra together with elemental analyses and mass spectra are clearly in agreement with the proposed structures. Preparation and Crystal Structure of [Hg(L 1 )Cl 2 ] (1). Reaction of L 1 in dichloromethane and HgCl 2 in methanol afforded a colorless complex precipitate, and single crystals of 1 suitable for X-ray analysis were obtained by vapor diffusion of diethyl ether into an acetonitrile solution of this complex. The FAB mass spectrum of 1 showed a peak at m/z 645.2 corresponding to [Hg(L 1 )Cl] + . The single crystal X-Figure 1. Synthesis of L 1 .