Structure and Reactivity of [Ru-Al] and [Ru-Sn] Heterobimetallic PPh3-Based Complexes

Treatment of [Ru(PPh3)(C6H4PPh2)(2)H][Li(THF)(2)] with AlMe2Cl and SnMe3Cl leads to elimination of LiCl and CH4 and formation of the heterobimetallic complexes [Ru(C6H4PPh2)(2){PPh2C6H4 AlMe(THF)}H] 5 and [Ru(PPh3)(C6H4PPh2)-(PPh2C6H4SnMe2)] 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 degrees C and with 6 at room temperature to yield the spectroscopically characterized trihydride complexes [Ru(PPh2)(2){PPh2C6H4AlMe}H-3] 7 and [Ru(PPh2)(2) {PPh2C6H4SnMe2}-H-3] 8. In the presence of CO, 6 forms the acylated phosphine complex, [Ru(CO)(2) (C(O)C6H4PPh2)(PPh2C6H4SnMe2] 9, through a series of intermediates that were identified by NMR spectroscopy in conjunction with (CO)-C-13 labeling. Complex 6 undergoes addition and substitution reactions with the N-heterocydic carbene 1,3,4,5-tetramethylimidazol-2-ylidene (IMe4) to give [Ru(IMe4)(2) (PPh2C6H4)(PPh2C6H4SnMe2)] 10, which converted via rare N-Me group C-H activation to [Ru(IMe4)(PPh3)-(IMe4)'(PPh2C6H4SnMe2)] 11 upon heating at 60 degrees C and to a mixture of [Ru(IMe4)(2)(IMe4)'(PPh2C6H4SnMe2)] 12 and [Ru(PPh3)(PPh2C6H4)(IMe4-SnMe2)'] 13 at 120 degrees C.

Automated summary

The reaction pathways between [Ru(PPh3)(C6H4PPh2)(2)H][Li(THF)(2)] and AlMe2Cl or SnMe3Cl have been investigated. It was found that complete reactions occurred at different temperatures to yield spectroscopically characterized trihydride complexes. In the presence of CO, complex 6 underwent a series of transformations to form an acylated phosphine complex. Complex 6 also reacted with an N-heterocydic carbene through addition and substitution reactions.