Influence of anionic sulfonate-containing and nitrogen-containing mixed-ligands on the structures of silver coordination polymers

Abstract

In this article, a series of mixed-ligand Ag(I) coordination polymers, namely, Ag(L1)H₂O (1), Ag₂(hmt)₂(L1)₂ (2), [Ag(HL2)]H₂O (3), [Ag(L2)(biim)][Ag(biim)] (4), [K₅(L3)₂][Ag(H₂O)₂] (5), [Ag₂(L3)(3-iso)][Ag(3-iso)]5H₂O (6), [Ag₃(L3)(bipy)₃(H₂O)]6H₂O (7), [Ag₃(L3)(biim)₃]H₂O (8), and [Ag₃(L3)(hmt)₂(H₂O)₃]H₂O (9) (where hmt = hexamethylenetetramine, bipy = 4,4′-bipyridine, biim = 1,1′-(1,4-butanediyl)-bis(imidazole), 3-iso = 3-methylisoquinoline, L1 = 2,5-dichloro-4-amino-benzenesulfonate anion, L2 = 2-nitroso-1-naphthol-4-sulfonate anion and L3 = 4-hydroxy-5-nitro-1,3-benzenedisulfonate anion), have been synthesized by varying the anionic sulfonate-containing ligands and nitrogen-containing secondary ligands. Compounds 2 and 4 were synthesized through their parent compounds 1 and 3, respectively, while 6–9 were obtained by their parent compound 5. Ag(I) centers of 1 are linked by L1 anions to generate a 1D polymeric chain, while Ag(I) centers of 2 are bridged by hmt ligands to form a 2D polymeric layer. In 3, Ag(I) centers are connected by L2 anions to yield a 1D double chain, whereas Ag(I) centers in 4 are joined by biim ligands and L2 anions, generating an unusual anionic chain and a cationic chain, respectively. In 5, Ag(I) centers are coordinated by water molecules, and K(I) cations are coordinated by L3 anions to form a pillared layered structure with inorganic layers and organic pillars. In 6, Ag(I) centers are coordinated by 3-iso ligands and L3 anions to generate a discrete molecular structure. In 7, bipy ligands bridge Ag(I) centers to give Ag–bipy chains, which are further linked by L3 anions to produce a 2D polymeric layer. In 8, Ag(I) centers are bridged by biim ligands to generate a 1D polymeric chain. In 9, the hmt ligands connect Ag(I) centers to give a binodal (3,4)-connected net with (6³)(6⁵.8)₂ topology. These results indicate that anionic sulfonate-containing ligands and the nitrogen-containing secondary ligands play important roles in the structural formation of the Ag(I) complexes. Additionally, the luminescent properties, elemental analyses and IR spectroscopy of these compounds were also studied.