Influence of dicarboxylic acids on self-assembly process: Syntheses and structural characterization of new Ag(I) complexes derived from mixed ligands

Using the principle of crystal engineering, three new silver metal-organic coordination polymers, [Ag-2(L1)(2)(L2)]center dot 2H(2)O (1), [Ag-2(L1)(2)(L3)]center dot H2O (2), [Ag-2(L1)(2)(L4)]center dot 2H(2)O (3) (L1 = 2-aminopyrimidine, L2 = oxalate anion, L3 = glutarate anion and L4 = 1,4-naphthalenedicarboxylate anion) have been synthesized by solution phase reactions of silver nitrate with various dicarboxylic acids and cooperative heterocyclic 2-aminopyrimidine ligand under the ammoniacal conditions. All the complexes have been characterized by elemental analyses, IR spectra and X-ray diffraction. In complex 1, L1 ligands are coordinated to Ag(I) metal centers in rare tridentate fashions, forming one-dimensional (1-D) ladder-like structure, which is interlinked by L2 anions to generate 2-D pleated molecular sheet. Complex 2 displays an interesting two-dimensional (2-D) tongue-and-groove structure containing a new kind of "T-shaped" unit. Meanwhile, each of 2-D bilayers is interlocked by four adjacent identical motifs to form three-dimensional (3-D) 5-fold interpenetrating conformation with weak Ag center dot center dot center dot Ag interactions. In complex 3, L1 ligands are coordinated to the Ag(I) ions to form 1-D polymeric chain. And L4 anions, acting as bridging linkers through corresponding mu(2)-carboxylates, link a pair of Ag(I) atoms from adjacent chains to yield 3-D supramolecular network. The structures of complexes 1-3 which span from 2-D to 3-D networks suggest that dicarboxylate anions play important role in the formation of such coordination architectures. (C) 2009 Elsevier Ltd. All rights reserved.