Structural Diversity of Silver Fluorinated β-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 β-diketonate ligands (R 1 C(O)C α HC(O)R 2 ) - we synthesized a series of the compounds containing tfac- (R 1 = CH 3 , R 2 = CF 3 ) and pfpac- (R 1 = CH 3 , R 2 = C 2 F 5 ) anions. Solvent-free [Ag(L)] ∞ (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 α 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 α bonds are connected through Ag-O bridge ones. Two structural types of chain coordination polymers, [Ag(tfac)(CH 3 CN)] 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) β-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.