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

POSE 1H and 19F diffusion data, D values, and 1H 19F HOESY NMR spectra for a series of [RuCl(p-cymene)(BINAP)]X salts, 2a-f, have been recorded in CD 2Cl 2 (X = BF 4- (2a), CF 3 SO 3- (2b), BArF - (2c), PF 6-(2d), SbF 6- (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(H 2O) 3(CO)(dppe)]X 2 (X = BF 4- (3a), CF 3SO 3- (3b), SbF 6 (3c), N(O 2SCF 3) 2- (3d)) are reported. The observed D values for 3a-d partially reflect hydrogen bonding from complexed water to the anions. © 2003 American Chemical Society

Reactivity of the N-heterocyclic carbene complexes [Ru(IMes)(2)(CO)HX] (X = OH, Cl) with alkynes

Treatment of the 16-electron hydroxy hydride complex [Ru(IMes)(2)(CO)H(OH)] (1, IMes = 1,3-bis-(2,4,6-trimethylphenyl)imidazol-2-ylidene) with HC CR affords the alkynyl species [Ru(IMes)(2)(CO) H(C CR)] (R = Ph 3, SiMe3, 4) and [Ru(IMes)(2)(CO)(C CR)(2)] (R = Ph, 5). Deuterium labelling studies show that the mono-alkynyl complexes are formed via hydrogen transfer from a coordinated alkyne ligand to Ru-OH, while bis-alkynyl formation is proposed to take place through hydrogen transfer to Ru-H. Both 3 and 5 readily coordinate CO to give the corresponding dicarbonyl species 6 and 7. Addition of HC CPh to the hydride chloride precursor [Ru(IMes)(2)(CO) HCl] (2) results in a different reaction pathway involving alkyne insertion into the Ru-H bond to yield the alkenyl chloride complex [Ru(IMes)(2)(CO)(CH=CHPh)Cl] 8. Complexes 3-8 have been structurally characterised by X-ray crystallography. (C) 2008 Elsevier B.V. All rights reserved

Mononuclear and dinuclear complexes with a [Ru(tBu2PCH2CH2PtBu2)(CO)] core.

Thermolysis of solid [Ru(d(t)bpe)(CO)2Cl2](2, d(t)bpe =(t)Bu2PCH2CH2P(t)Bu2) under vacuum affords the five-coordinate complex [Ru(d(t)bpe)(CO)Cl2] (4), which was shown by X-ray crystallography to contain a weak remote agostic interaction. In solution, 4 can be readily trapped by CO, CH3CN or water to give [Ru(d(t)bpe)(CO)(L)Cl2](L = CO, 2; L = CH3CN, 6; L = H2O, 7). Reaction of 4 with AgOTf/H2O yields the tris-aqua complex [Ru(d(t)bpe)(CO)(H2O)3](OTf)2 (8), which has been structurally characterised and probed in solution by pulsed-gradient spin echo (PGSE) NMR spectroscopy. The water ligands in 8 are labile and easily substituted to give [Ru(d(t)bpe)(CO)(NCCH3)3](OTf)2 (10) and [Ru(d(t)bpe)(CO)(DMSO)3](OTf)2 (11). In the presence of CO, the tris-aqua complex undergoes water-gas shift chemistry with formation of the cationic hydride species [Ru(d(t)bpe)(CO)3H](OTf) (12) and CO2. X-Ray crystal structures of complexes 2, 4, 6, 8 and 11-12 are reported along with those for [{Ru(d(t)bpe)(CO)}2(mu-Cl)2(mu-OTf)](OTf) (3), [{Ru(d(t)bpe)(CO)}2(mu-Cl)3][Ru(d(t)bpe)(CO)Cl3](5) and [Ru(d(t)bpe)(CO)(H2O)2(OTf)](OTf)(9)