Structural Diversity of Silver Fluorinated beta-Diketonates: Effect of the Terminal Substituent and Solvent

In order to demonstrate the role of the fluorination and some solvents in the structural organization of the Ag(I) coordination polymers with beta-diketonate ligands ((RC)-C-1(O)C alpha HC(O)R-2)(-) we synthesized a series of the compounds containing tfac- (R-1 = CH3, R-2 = CF3) and pfpac- (R-1 = CH3, R-2 = C2F5) anions. Solvent-free [Ag(L)](& INFIN;) (L = tfac 1, pfpac 2) compounds and the corresponding acetonitrile and toluene adducts have been characterized by elemental analysis and/or NMR, IR and single-crystal XRD. This series includes five new coordination polymers. Compound 1 is a 3D coordination framework based on Ag-O-chelate/bridge, Ag-C-alpha bonds, and argentophilic interactions. An increase in the fluorinated group leads to a chain coordination polymer 2 of an unusual structural organization. These chains can be represented as a "DNA-type ", where two intertwined helices based on Ag-O-chelate and Ag-C-alpha bonds are connected through Ag-O-bridge ones. Two structural types of chain coordination polymers, [Ag(tfac)(CH3CN)] and [Ag-2(L)(2)(solvent)], have been revealed for the adducts. The latter structural type differs significantly from the previously studied toluene and acetonitrile adducts of fluorinated Ag(I) beta-diketonates of the same stoichiometry. Thermal analysis in helium showed that both 1 and 2 decompose to metallic silver with the compound of pfpac-ligand being slightly more stable.