PGSE diffusion studies on chelating phosphine complexes of ruthenium(II). Solvent dependence and ion pairing

PGSE H-1 and F-19 diffusion data, D values, and H-1,F-19 HOESY NXIR spectra for a series of [RuCl(p-cymene)(BINAP)]X salts, 2a-f, have been recorded in CD2Cl2 (X = BF4- (2a), CF3 SO3- (2b), BArF- (2c), PF6- (2d), SbF6- (2e), Cl- (2f)). The solvent dependence of the D values for 2a-c in methanol, chloroform, dichloromethane, and acetone and the resulting ion-pairing effects are discussed. On the basis of HOESY data, it is suggested that small anions in chloroform solution approach the ruthenium atom from the side of the molecule remote from the chloride and slightly below the complexed arene. PGSE diffusion data for the Ru-aqua complexes [Ru(H2O)(3)(CO)(dppe)]X-2 (X = BF4- (3a), CF3SO3- (3b), SbF6- (3c), N(O2SCF3)(2)(-) (3d)) are reported. The observed D values for 3a-d partially reflect hydrogen bonding from complexed water to the anions.