Supramolecular assemblies of metal ions in complex bimetallic and trimetallic salts based on hexacyanoferrate(III) ion

Abstract

Two complex heterometallic salts with formulae Tl6[Fe(CN) 6]1.33(NO3)(OH) (1) and [Co(bpy) 2(CN)2]2{[Ag(CN)2] 0.5[Fe(CN)6]0.5}·8H2O (2) have been synthesized and fully characterized. Single crystal X-ray analyses reveal that compound 1 is comprised of discrete Tl+ cations and [Fe(CN)6]3- anions together with OH- and NO3- anions. Compound 2 contains [Co(bpy)2(CN)2]+ cations and {[Ag(CN)2][Fe(CN)6]}- anions together with eight molecules of water of crystallization. Both structures form unprecedented three-dimensional supramolecular networks via non-covalent interactions. Another important observation is that the stereochemically active inert (lone) pair present on Tl+ plays little role in controlling the structure of 1. The water molecules in 2 play important roles in providing stability, organizing a supramolecular network through hydrogen bonding. In the syntheses of 1 and 2, Fe(II) is oxidized to Fe(III) and Co(II) to Co(III), respectively, facilitating the formation of the salts that are obtained. Both compounds exhibit photoluminescence emission in solution near the visible region. © 2010 Elsevier Ltd. All rights reserved.