Binucleating Aza‐Sulfonate and Aza‐Sulfinate Macrocycles — Synthesis and Coordination Chemistry

The preparation and ligating properties of S‐oxygenated derivatives of a macrobinucleating hexaazadithiophenolate macrocycle H 2 L 1 of the Robson type towards nickel( II ) and zinc( II ) ions are reported. Nickel complexes of the hexaazadiphenylsulfonate ligand (L 2 ) 2− [(L 2 )Ni II 2 (μ‐L)] + (L = m ‐Cl‐OBz − ( 3 ), Cl − ( 4 ) and OAc − ( 6 )] are readily obtained in high yields by oxidation of the respective [(L 1 )Ni II 2 (μ‐L)] + parent complexes [L = m ‐Cl‐OBz − ( 2 ), Cl − ( 1 ), OAc − ( 5 )] with meta ‐chloroperoxybenzoic acid or hydrogen peroxide. Decomposition of the sulfonate complexes gives the free macrocycle H 2 L 2 which, upon treatment with Zn(OAc) 2 ·2H 2 O, produces the diamagnetic zinc complex [(L 2 )Zn II 2 (OAc)] + ( 8 ). A dinuclear Cu II complex of the hexaazadisulfinate derivative (L 3′ ) 2− , [(L 3 )Cu II 2 ] 2+ ( 9 ), is formed rather unexpectedly by air oxidation of (L 1 ) 2− in the presence of Cu I . The crystal‐structure determinations of the perchlorate or tetraphenylborate salts of 2 , 3 , and 4 show that the new ligands support the formation of binuclear complexes with bowl‐shaped, calixarene‐like binding cavities. NMR spectroscopic studies of 8 show that the complexes retain their solid‐state structures in solution. A crystal‐structure determination of 9 reveals two five‐coordinate Cu II ions bridged by the two sulfinate functions of (L 3 ) 2− . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)