PREPARATION AND NMR-SPECTRA OF DIFLUOROMETHYLATED SILVER(I) AND SILVER(III) COMPOUNDS - STRUCTURE OF [PNP][AG(CF2H)(4)](+)

thermally unstable [Ag(CF2H)(2)](-) moiety is obtained in solution by reaction of silver(I) salts with Cd(CF2H)(2) in DMF/diglyme at -80 deg rees C. Oxidation with 12 leads to the argentate(III) [Ag(CF2H)(4)](-) , which has been isolated as its PNP salt. According to DSC/TG analysi s, the exothermic decomposition of this air-stable salt proceeds in tw o steps at 121 and 150 degrees C with formal elimination of one and th ree CFH units, respectively. Difluoromethylation of [Ag(CN)(2)](-) in the presence of acetyl chloride leads to the argentate(I) [Ag(CF2H)(CN )](-); which is oxidized by bromine at low temperatures to the thermal ly labile [trans-Ag(CF2H)(2)(CN)(2)](-) anion. Stable argentates(III) containing both difluoromethyl and trifluoromethyl groups are obtained by reaction of [Ag(CF3)(n)(CN)(4-n)](-) (n = 1, 2-cis, 2-trans, and 3 ) with Cd(CF2H)(2)-the cis and trans configurations of the reactants b eing retained in their products for n = 2. The compounds are identifie d and characterized by multinuclear NMR spectroscopy. Crystals of [PNP ][Ag(CF2H)(4)] belong to the tetragonal space group P4(3) with a = 9.4 75(1) Angstrom, c = 42.159(6) Angstrom, and Z = 4. The coordination of the silver atom is approximately square-planar with an average Ag-C b ond length of 2.083(14) Angstrom. The ligands are so oriented that eac h C-H bond is geared between the C-F bonds of a neighboring CF2H group -the overall symmetry being approximately C-4h.