PREPARATION AND NMR-SPECTRA OF THE (TRIFLUOROMETHYL)ARGENTATES(III) [AG(CF3)(N)X(4-N)](-), WITH X=CN (N=1-3), CH3, C=CC6H11, CL, BR (N=2, 3), AND I (N=3), AND OF RELATED SILVER(III) COMPOUNDS - STRUCTURES OF [PPH(4)][TRANS-AG(CF3)(2)(CN)(2)] AND [PPH(4)][AG(CF3)(3)(CH3)]

Trifluoromethylation of [Ag(CN)(2)](-) with (CF3)(2)Cd . diglyme yield s [Ag(CF3)(CN)](-). The anion is readily oxidized by bromine to the ar gentates(III), [Ag(CF3)(n)(CN)(4-n)](-), n = 1-4. The stability of the se species decreases with an increasing number of CN groups. Halogenat ion of these complexes with acetyl chloride or with bromine affords th e moderately stable (n = 3) or unstable (n = 2) haloargentates of the type [Ag(CF3)(n)X(4-n)](-), X = Cl or Br. Their dehalogenation with Ag NO3 in a donor solvent D gives the adducts [Ag(CF3)(3)D] and [Ag(CF3)( 2)D-2](+), respectively. Decomposition of most argentates(III) proceed s by reductive elimination of CF(3)X (X = Cl, Br, or CN), but ligand e xchange with participation of the CS groups is also observed. The latt er is used to prepare Ag(CF3)(3) derivatives from the readily accessib le [trans-Ag(CF3)(2)(CN)(2)](-) anion. The syntheses of methyl(trifluo romethyl)argentates(III) and of cyclohexylethynyl)(trifluoromethyl)arg entates(III) are accomplished by reaction of the cyanoargentates (n = 2, 3) with CH3MgCl or LiC equivalent to CC6H11, respectively. Often mu ltinuclear (Ag-109, F-19, C-13, H-1) NMR data of transient and stable Ag(III) species establish unambiguously not only their constitution bu t also the square-planar coordination of the metal. Couplings to the s pin-1/2 silver nuclei are interpreted on the basis of 5s(Ag) orbital p articipation in competition with 4d orbital contributions to Ag-CF3 bo nding. Crystals of [PPh(4)][Ag(CF3)(2)(CN)(2)] belong to the monoclini c space group C2/c, with a 18.174(2) A, b = 7.8881(8) Angstrom, c = 18 .881(2) Angstrom, beta = 93.036(8)degrees, and Z = 4, whereas [PPh(4)] [Ag(CF3)(3)(CH3)] crystallizes in the orthorhombic space group Pca2(1 ), with a = 24.941(3) Angstrom, b = 7.2629(6) Angstrom, c = 14.9985(14 ) Angstrom, and Z = 4. The coordination environments of these two arge ntates are approximately square planar. The Ag-CF3 bonds in the dicyan o complex (2.105(4) Angstrom) are distinctly longer than the Ag-CN lin kages (2.013(3) Angstrom). In the [Ag(CF3)(3)(CH3)](-) anion, the Ag-C H3 distance (2.097(5) Angstrom) is slightly shorter than the average A g-CF3 bond lengths (2.119(10) Angstrom).