Assembly of Silver(I) Complexes of Isomeric NS2-Macrocycles Displaying Cyclic Oligomer, Helix, and Zigzag Structures

An isomeric series of NS2-macrocycles, incorporating ortho- (o-L), meta- (m-L), and para-xylyl (p-L) groups in their backbones between the sulfur donors, have been synthesized. A comparative investigation of the coordination behavior of these macrocyclic ligands with silver­(I) salts is reported. The X-ray structures of six complexes (1–6) were determined, and a variety of structural types that range from cyclic oligomers to zigzag or helical chains is shown to occur. Reactions of o-L with silver nitrate and perchlorate afforded three complexes with different topologies: the cyclic hexamer [Ag6(o-L)6]­(NO3)6·0.5DMF·7H2O (1), the cyclic hexamer with two terminal complex units [Ag8(o-L)8]­(ClO4)8 (2), and a one-dimensional (1D) zigzag coordination polymer of type {[Ag2(o-L)2]­(ClO4)2·2CH3CN·CHCl3}n (3). Reaction of m-L with silver­(I) perchlorate gave the 1D zigzag coordination polymer, {[Ag­(m-L)]­ClO4·CH2Cl2}n (4). Reaction of p-L with silver perchlorate yielded a crystalline product whose X-ray analysis confirmed it to be a mixture of two different species: the discrete helical complex {[Ag3(p-L)3]­(ClO4)3}n (5) and the cyclic tetramer [Ag4(p-L)4(ClO4)4]·3DMF (6). The influence of macrocyclic ring flexibility and sulfur donor atom spacing on the topologies adopted by the respective complexes is discussed.