Structural diversity in the self-assembly of Ag(I) complexes containing 2-amino-5-halopyrimidine

A series of Ag(I) complexes containing the 2-amino-5-halopyrimidine ligands have been synthesized and their structures characterized by X-ray crystallography. The isomorphous complexes Ag(L-CI)(2)(CF3SO3) (L-CI = 2-amino-5-chloropyrimidine), 1, and Ag(L-Br)(2)(CF3SO3) (L-Br = 2-amino-5-bromopyrimidine), 2, are mononuclear, while [Ag(L-Br)(CF3SO3)](6)center dot 6C(4)H(10)O, 3, and [Ag(L-I)(CF3SO3)](6) (L-I = 2-amino-5-iodopyrimidine), 4, show cyclic self-assembly of six Ag(I) atoms and six L-X ligands, resulting in 24-membered metallocycles. The complex [Ag(L-I)(CF3SO3)](infinity), 5, forms 1D zigzag chains which are linked through C-I center dot center dot center dot Ag and Ag center dot center dot center dot O interactions to form a 3D structure. The tetranuclear complexes [Ag(L-X)(NO3)](4) [X = Cl, 6; Br, 7] form 16-membered metallocycles, while [Ag(L-X)(ClO4)](infinity) [X = Cl, 8: Br, 9] exhibit helical chains. The different structure of S from 1 and 2 appears to be due to the stronger nucleophilic character of the iodine atom. In these complexes, the relatively smaller NO3- anions lead to the formation of tetranuclear metallocycles and the larger CF3SO3- anions support the hexanuclear metallocycles, whereas the ClO4- anions induce the helical chains. (C) 2011 Elsevier Ltd. All rights reserved.