Reactions of Ruthenium–Aminophosphane Complexes with Diynes: P–N Bond Activation and Formation of Novel Phosphaallyl, Azaallyl, and Aminocarbene Complexes

Abstract

The aminophosphane complexes [RuCp(PPh2NRR′2)(CH3CN)2]+ and [RuCp*(PPh2NRR′2)(CH3CN)2]+ (NRR′ = NHnPr, NEt2, NC5H5) react with 1,6‐heptadiyne and 1,7‐octadiyne to yield novel η3‐phosphaallyl–η2‐vinylamine complexes of the types [RuCp{η3‐(P,C,C)‐PPh2CH=C–(CH2)n–η2‐(C,C)–C=CHNRR′2}]+ and [RuCp*{η3‐(P,C,C)‐PPh2CH=C–(CH2)n–η2‐(C,C)‐C=CHNRR′2}]+ (n = 3, 4). These complexes are the kinetic products but eventually form the η1‐phosphaallyl–η3‐azaallyl complexes [RuCp{η1‐(P)‐PPh2CH=C–(CH2)n–η3‐(C,C,N)‐CCHNRR′2}]+ and [RuCp*{η1‐(P)‐PPh2CH=C–(CH2)n–η3‐(C,C,N)‐CCHNRR′2}]+, respectively. With n = 3 elevated temperatures are required, while with n = 4 this conversion takes places already at room temperature. The only exception is [RuCp*(PPh2NHnPr)(CH3CN)2]+ where amido butadiene complexes [RuCp*{η1‐(N)‐NnPrPPh2‐η4‐CH=C(CH2)nCH=CH2}]PF6 (n = 3, 4) are obtained instead. In the case of [RuCp{η1‐(P)‐PPh2CH=C–(CH2)3–η3‐(C,C,N)‐CCHNRR′2}]+ with NRR′ = NEt2 and NC5H5, a further rearrangement took place at elevated temperatures affording the aminocarbenes [RuCp{=C(NRR′)‐η2‐(C,C)‐C(CH2)3C–CH2–(η1‐(P)‐PPh2)}]+. Representative X‐ray structures are presented. Moreover, conceivable mechanisms for all these reaction sequences are established by means of DFT/B3LYP calculations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Chlorido(chlorodiphenylphosphine-κP)(diphenylpiperidinophosphine-κP)(η5-pentamethylcyclopentadienyl)ruthenium(II)

“…For general background to the reaction of half-sandwich ruthenium aminophosphine complexes with diynes, see: Pavlik et al (2006). For the unexpected formation and the crystal structure of a related Ru chlorodiphenylphosphine complex, see: Torres-Lubia et al (1999).…”

“…We found that halfsandwich ruthenium aminophosphine complexes [Ru(Cp′)(κ 1 P-Ph 2 PNRR′) 2 (CH 3 CN) 2 ] + (Cp′ is either Cp = cyclopentadienyl or Cp* = pentamethylcyclopentadienyl; Ph = phenyl; NRR′ = NH n Pr, NEt 2 , or NC 5 H 10 = piperidin-1-yl) react with diynes to afford novel η 3 -phosphaallyl-η 2 -vinylamine complexes and may transform under certain conditions to aminocarbenes (Pavlik et al, 2006). In continuation of this work we were interested to react [Ru(Cp*)(κ 1 P-Ph 2 PNC 5 H 10 )Cl 2 ], a Ru(III) complex, with NaBH 4 in order to obtain a hydrido or borohydride complex.…”

(η3-Allyl)bromo(η5-cyclopentadienyl)(phenylaminodiphenylphosphine-κP)ruthenium(IV) hexafluorophosphate

“…Ruthenium complexes with cyclopentadienyl (Cp), pentamethylcylopentadienyl (Cp*) or hydridotrispyrazolylborate (Tp) as ancillary ligand and phenylaminodiphenylphosphine (Ph 2 PNHPh) as coligand have recently attracted attention because of a rich chemistry in stoichiometric or catalytic transformations of alkenes and alkynes (Pavlik et al, 2003(Pavlik et al, , 2006Pavlik, Jantscher et al, 2005;Priya et al, 2003;Jimenez-Tenorio et al, 2005). For Cp, such compounds are accessible from the cationic complex [RuCp(Ph 2 PNHPh)(CH 3 CN) 2 ] + (Pavlik et al, 2003), which behaves as a masked electron-deficient entity and reacts under mild conditions with unsaturated hydrocarbons.…”