Synthesis and structures of organometallic aqua complexes of ruthenium(II)

Treatment of all-cis-Ru(dppe)(CO)(2)Cl-2 (dppe = Ph2PCH2CH2PPh2) with 2 equiv of AgOSO2CF3 yields the bis(triflate) complex Ru(dppe)(CO)(2)(OSO2CF3)(2) (1), which has been characterized by NMR spectroscopy and X-ray crystallography. Exposure of solid 1 to atmospheric moisture gives the carbonyl aqua complex Ru(dppe)(CO)(H2O)(OSO2CF3)(2) (2). The X-ray structure of 2 shows both intra- and intermolecular hydrogen bonding between the coordinated water and,triflates. The F-19 NMR spectra of 1 and 2 display coupling between the triflate groups; F-19-F-19 NOESY suggests that this arises from both through-bond and through-space coupling. The reaction of 1 with 10 equiv of water results in the rapid formation of a species assigned as the cationic diaqua complex [Ru(dppe)(CO)(H2O)(2)(OSO2CF3)][OSO2CF3] (3). Over a longer period of time, further reaction occurs to form the triaqua carbonyl complex [Ru(dppe)(CO)(H2O)(3)][OSO2CF3](2) (4), which has also been characterized by X-ray crystallography. The structure of 4 indicates that all three water ligands participate in hydrogen bonding. Complex 4 is unstable in the absence of water, re-forming a mixture of 1 and 2.