Areneruthenium(ii) complexes containing bulky phosphines with various functionalities as ligands

Abstract

The dimeric starting materials [Ru(η⁶-arene)Cl₂]₂ (arene = mes, C₆Me₆) react with the functionalized phosphines Prⁱ₂PCH₂X (X = CH₂OMe, CO₂Me) to give the mononuclear compounds [Ru(η⁶-arene)(κP-Prⁱ₂PCH₂X)Cl₂] 3–6 which upon treatment with AgPF₆ afford the chelate complexes [Ru(η⁶-arene)(κ²P,O-Prⁱ₂PCH₂CH₂OMe)Cl]PF₆7, 8 and [Ru(η⁶-arene){κ²P,O-Prⁱ₂PCH₂C(O)OMe}Cl]PF₆9, 10, respectively. Complexes 7 and 8 react with CO and CNBu^t to yield the chiral-at-metal compounds [Ru(η⁶-arene)(κP-Prⁱ₂PCH₂CH₂OMe)(L)Cl]PF₆11–14. Treatment of 8 (arene = C₆Me₆) with Na₂CO₃ in the presence of water produces the carbonatoruthenium(II) derivative [Ru(η⁶-C₆Me₆)(κ²O,O-O₂CO)(κP-Prⁱ₂PCH₂CH₂OMe)] 17. The reaction of 9 (arene = mes) with KOBu^t leads to the formation of the uncharged phosphinoester enolate complex [Ru(η⁶-mes)(κ²P,O-Prⁱ₂PCHC(O)OMe)Cl] 18 which in benzene at room temperature smoothly rearranges to the phosphinomethanide isomer [Ru(η⁶-mes)(κ²P,C-Prⁱ₂PCHCO₂Me)Cl] 19. The corresponding phosphinoacetate complexes [Ru(η⁶-arene){κ²P,O-Prⁱ₂PCH₂C(O)O}Cl] 21, 22 were obtained as the major products from 5 or 6 and NaH/Al₂O₃ in THF. Compound 18 reacts with water by ester hydrolysis to form 21 and with phenylisocyanate and diphenylketene to afford 24 and 25 by insertion of the heterocumulene into the enolate C–H bond. The molecular structures of 19 and 25 were determined crystallographically.