Substitution Reactions of [Ru(dppe)(CO)(H2O)3][OTf]2

The labile nature of the coordinated H2O ligands in the organometallic aqua complex [Ru(dppe)(CO)(H2O)3][OTf]2 (1) (dppe = Ph2PCH2CH2PPh2; OTf = OSO2CF3) was studied through substitution reactions with a range of incoming ligands. Dissoln. of 1 in MeCN or DMSO results in the facile displacement of all three waters to give [Ru(dppe)(CO)(MeCN)3][OTf]2 (2) and [Ru(dppe)(CO)(DMSO)3][OTf]2 (3), resp. Similarly, 1 reacts with Me3CNC to afford [Ru(dppe)(CO)(CNCMe3)3][OTf]2 (4). Addn. of 1 equiv of 2,2'-bipyridyl (bpy) or 4,4'-dimethyl-2,2'-bipyridyl (Me2bpy) to acetone/water solns. of 1 initially yields [Ru(dppe)(CO)(H2O)(bpy)][OTf]2 (5a) and [Ru(dppe)(CO)(H2O)(Me2bpy)][OTf]2 (6a), in which the coordinated H2O lies trans to CO. Compds. 5a and 6a rapidly rearrange to isomeric species (5b, 6b) in which the ligated H2O is trans to dppe. Further reactivity was demonstrated for 6b, which, upon dissoln. in CDCl3, loses H2O and coordinates a triflate anion to afford [Ru(dppe)(CO)(OTf)(Me2bpy)][OTf] (7). Reaction of 1 with CH3CH2CH2SH gives the dinuclear bridging thiolate complex [{(dppe)Ru(CO)}2(micro -SCH2CH2CH3)3][OTf] (8). The reaction of 1 with CO in acetone/H2O is slow and yields the cationic hydride complex [Ru(dppe)(CO)3H][OTf] (9) via a water gas shift reaction. also, the same mechanism can also be used to account for the previously reported synthesis of 1 upon reaction of Ru(dppe)(CO)2(OTf)2 with H2O (Organometallics 1999, 18, 4068).