Mono- and dinuclear silver(I) complexes of benzene- and pyridine-bearing 20-membered thiaoxaaza macrocycles Kaniz Fatima Sultana, So Young Lee, Ji-Eun Lee, Joobeom Seo, Shim Sung Lee * Department of Chemistry (BK21) and Research Institute of Natural Science, Gyeongsang National University, Jinju 660-701, South Korea Received 7 August 2007; accepted 18 September 2007 Available online 5 November 2007 Abstract Two 20-membered penta- and hexadentate macrocycles containing one or two pyridine subunits, namely [20]aneNO 2 S 2 (L 1 ) and [20]aneN 2 O 2 S 2 (L 2 ), have been synthesized. Reaction of L 1 with silver(I) nitrate afforded a unique 2:2 (M:L) disilver(I) complex [l 2 - Ag 2 (L 1 ) 2 ](NO 3 ) 2 (1) in which two four-coordinate Ag atoms bridge two ligands to form a cyclic dimer. In contrast, an endo-dentate 1:1 monosilver(I) complexes [AgL 2 ]X; [X = ClO 4 (2) or PF 6 (3)] which show isomorphous structures were obtained from the reactions of L 2 with silver(I) salts. Ó 2007 Elsevier B.V. All rights reserved. Keywords: Thiaoxaaza macrocycle; Pyridine subunit; Mono- and disilver(I) complexes; NMR The synthesis and characterization of macrocyclic com- plexes have laid the foundation of modern supramolecular chemistry [1]. Although a number of macrocyclic com- plexes have been studied during the past four decades, the coordination behavior of the macrocyclic ligands toward metal ions is not entirely predictable, especially when different donor sets are present [2]. Our group [3] and others [4] have reported a series of coordination poly- mers and discrete-type supramolecular complexes with the triple-mixed (N/O/S) macrocycles. Parallel to this, pyri- dine-containing macrocycles are of particular interest due to the effective coordination ability of pyridine [5]. Taking these reasons into account, we are interested in the macro- cycles employing the triple-mixed donor-set together with the pyridine subunit as ring cavity members. Herein we report the synthesis of the 20-membered N n O 2 S 2 -donor macrocycles (n = 1: L 1 and n = 2: L 2 ) with benzene and pyridine subunits, and their crystal structures of silver(I) complexes. L 1 and L 2 were synthesized by coupling reactions between dibenzopyridyl dichloride [6] and corresponding dithiols [7] in the presence of Cs 2 CO 3 in moderate yields (20% and 15%, respectively) [8,9] (Scheme 1). Colorless crystalline complex 1 [10] suitable for X-ray analysis was obtained from the reaction of L 1 with AgNO 3 in CH 3 CN/CH 2 Cl 2 . The X-ray analysis [11] revealed that 1 is a unique binuclear cyclic dimer of formula [l 2 - Ag 2 (L 1 ) 2 ](NO 3 ) 2 (1) (Fig. 1). Each Ag atom in 1 is four-coordinated by one S, one O and one N atoms from one L 1 , and one S atom from another L 1 , which led to the forming of the cyclic dimer complex. As might be expected, the pyridine N atom provides the strongest to Ag atom [Ag1–N1 2.360(3) A ˚ ]. The Ag–S bond distances in 1 [Ag1–S2 2.468(1), Ag1–S1A 2.497(1) A ˚ ] are typical but shorter than those in complexes 2 and 3 [2.626(1)– 1387-7003/$ - see front matter Ó 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.inoche.2007.09.012 * Corresponding author. Tel.: +82 55 751 6021; fax: +82 55 753 7614. E-mail address: sslee@gnu.ac.kr (S.S. Lee). www.elsevier.com/locate/inoche Available online at www.sciencedirect.com Inorganic Chemistry Communications 10 (2007) 1496–1500