SILVER(I) COMPLEXES OF DICHLOROMETHANE AND 1,2-DICHLOROETHANE

The complexes [Ag(CH2Cl2)(OTeF5)]2 (1), [Ag(1,2-C2H4Cl2)(OTeF5)]2 (2), Ag2(CH2Cl2)4Pd(OTeF5)4 (3), and Ag2(1,2-C2H4Cl2)4Pd(OTeF5)4 (4) have been prepared and studied by solution conductimetry, by tensimetric titrations with dichloromethane vapor, and by IR, Raman, liquid and solid, 13C NMR, and 35Cl NQR spectroscopy. In addition, the structures of compounds 2, 3, and 4 have been determined by single-crystal X-ray diffraction methods: 2, orthorhombic, Pbca, a = 13.371 (5) Å, b = 8.192 (2) Å, c = 32.720 (9) Å, Z = 4, T = -120 °C, R = 0.052; 3, triclinic, PĪ, a = 8.923 (2) Å, b = 9.953 (3) Å, c = 9.985 (2) Å, α = 114.23 (2)°, β = 100.54 (2)°, γ = 91.42 (2)°, Z = 1, T = -130 °C, R = 0.041; 4, triclinic, P ī, a = 9.571 (2) Å, b = 10.314 (3) Å, c = 10.399 (2) Å,α= 106.37 (2)°, β = 91.98 (2)°, γ = 112.21 (2)°, Z = 1, T = -127 °C, R = 0.025. These compounds provide the first unambiguous evidence that simple chlorinated hydrocarbons can coordinate to metal ions. The AgCl distances span the ranges 2.626 (3)-3.000 (3) Å (2), 2.775 (2)-2.882 (2) Å (3), and 2.645 (Q-2.928 (1) Å (4) and are all much shorter than the sum of van der Waals radii for silver and chlorine, 3.45 ± 0.05 Å. Dichloromethane and 1,2-dichloroethane coordinate to the Ag(I) ions in bidentate fashion, forming four-(3) and five-membered chelate rings (2, 4). In addition, a chlorine atom in 2 bridges two Ag(I) ions. The Ag(I) ions are coordinated to two (2), three (2), or four (3, 4) chlorine atoms from dichloromethane or 1,2-dichloroethane molecules. Bond distances and angles for the coordinated chlorocarbonmolecules are not significantly different than for the corresponding noncoordinated molecules. Solid-state spectroscopic data, including v(CCl) stretching frequencies, 13C NMR chemical shifts, and 35C1 NQR frequencies, show the effects of coordination on the spectra of the parent solvent molecules, criteria that can be used to demonstrate chlorocarbon coordination in the absence of a crystal structure. Tensimetric titrations of AgX solids with dichloromethane vapor show the order of formation of a 1:1 AgX-CH2Cl2 complex is X- = OTeF5- (P1/2 = 4 (1) Torr) > 1/2Pd(OTeF5)42- (P,1/2 = 14 (1) Torr) > SbF6- (P1/2 = 22 (1) Torr) » Cl- (AgCl showed no evidence of complex formation with dichloromethane). The unsolvated compounds AgOTeF5 and Ag2Pd(OTeF5)4 are weak electrolytes in dichloromethane and 1,2-dichloroethane, suggesting that small amounts of Ag(CH2Cl2)n+ and Ag(1,2-C2H4C12)n+ may be produced. The compound AgOTeF5, while stable indefinitely dissolved in dichloromethane, 1,2-dichloroethane, 1,1,2-trichloroethane, and 1,1,2,2-tetrachloroethane, rapidly forms AgCl and other organic products when dissolved in trichloromethane, tetrachloromethane, 1,1-dichloroethane, trans-1,2-dichlorocyclohexane, 1-chloro-2,2,2-trifluoroethane, and 1-chlorobutane. © 1990, American Chemical Society. All rights reserved.