Structure and Reactivity of [Ru-Al] and [Ru-Sn] Heterobimetallic PPh 3 -Based Complexes.

Treatment of [Ru(PPh 3 )(C 6 H 4 PPh 2 ) 2 H][Li(THF) 2 ] with AlMe 2 Cl and SnMe 3 Cl leads to elimination of LiCl and CH 4 and formation of the heterobimetallic complexes [Ru(C 6 H 4 PPh 2 ) 2 {PPh 2 C 6 H 4 AlMe(THF)}H] 5 and [Ru(PPh 3 )(C 6 H 4 PPh 2 )(PPh 2 C 6 H 4 SnMe 2 )] 6 , respectively. The pathways to 5 and 6 have been probed by variable temperature NMR studies, together with input from DFT calculations. Complete reaction of H 2 occurs with 5 at 60 °C and with 6 at room temperature to yield the spectroscopically characterized trihydride complexes [Ru(PPh 2 ) 2 {PPh 2 C 6 H 4 AlMe}H 3 ] 7 and [Ru(PPh 2 ) 2 {PPh 2 C 6 H 4 SnMe 2 }H 3 ] 8 . In the presence of CO, 6 forms the acylated phosphine complex, [Ru(CO) 2 (C(O)C 6 H 4 PPh 2 )(PPh 2 C 6 H 4 SnMe 2 )] 9 , through a series of intermediates that were identified by NMR spectroscopy in conjunction with 13 CO labeling. Complex 6 undergoes addition and substitution reactions with the N-heterocyclic carbene 1,3,4,5-tetramethylimidazol-2-ylidene (IMe 4 ) to give [Ru(IMe 4 ) 2 (PPh 2 C 6 H 4 )(PPh 2 C 6 H 4 SnMe 2 )] 10 , which converted via rare N-Me group C-H activation to [Ru(IMe 4 )(PPh 3 )(IMe 4 )'(PPh 2 C 6 H 4 SnMe 2 )] 11 upon heating at 60 °C and to a mixture of [Ru(IMe 4 ) 2 (IMe 4 )'(PPh 2 C 6 H 4 SnMe 2 )] 12 and [Ru(PPh 3 )(PPh 2 C 6 H 4 )(IMe 4 -SnMe 2 )'] 13 at 120 °C.