Synthesis and Structures of Organometallic Aqua Complexes of Ruthenium(II)

Treatment of all - cis -Ru(dppe)(CO) 2 Cl 2 (dppe = Ph 2 PCH 2 CH 2 PPh 2 ) with 2 equiv of AgOSO 2 CF 3 yields the bis(triflate) complex Ru(dppe)(CO) 2 (OSO 2 CF 3 ) 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)(H 2 O)(OSO 2 CF 3 ) 2 ( 2 ). The X-ray structure of 2 shows both intra- and intermolecular hydrogen bonding between the coordinated water and triflates. The 19 F NMR spectra of 1 and 2 display coupling between the triflate groups; 19 F− 19 F 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)(H 2 O) 2 (OSO 2 CF 3 )][OSO 2 CF 3 ] ( 3 ). Over a longer period of time, further reaction occurs to form the triaqua carbonyl complex [Ru(dppe)(CO)(H 2 O) 3 ][OSO 2 CF 3 ] 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 .