Hydrochlorination of Ruthenaphosphaalkenyls: Unexpectedly Facile Access to Alkylchlorohydrophosphane Complexes
摘要:
The novel ruthenaphosphaalkenyls [Ru{P=C(H)SiMe2R}Cl-(Co)(PPh3)(2)] (R = p-C6H4CF3, Bu-n) have been prepared for the first time, and studied alongside precedent analogues (R = Me, Ph, p-tol) for their reactions with HCl. In contrast to chemistry defined for the tert-butyl congener [Ru{P,=C(H)Bu-t}CI(CO)(PPh3)(2)], which initially adds a single equivalent of HCI across the Ru-P linkage, all five silyl derivatives undergo spontaneous addition of a second equivalent to afford [Ru{eta(1)-PHCI-CH2SiMe2R}Cl(Co)(PPh3)(2)], extremely rare examples of coordinated "PHXR." type ligands. Where R = SiMe3, a distorted octahedral geometry with a conformationally restricted 'PHXR" ligand is observed crystallographically; this structure is appreciably retained in solution, as determined from multinuelear NMR spectroscopic features, which include a Karplus-like P-pph3-Ru-P-H spin-spin coupling dependence. Computational data suggest a silyl-induced increase in negative charge density at the phosphaalkenic carbon, rather than an intrinsic thermodynamic driver, as the likely origin of the disparate reactivity.
Complete metal-mediated reduction of the triple bond of a phosphaalkyne: X-ray structure of [Ru(PHFCH<sub>2</sub>Bu<sup>t</sup>)Cl(CO)(CNC<sub>6</sub>H<sub>3</sub>Me<sub>2</sub>-2,6)(PPh<sub>3</sub>)<sub>2</sub>]BF<sub>4</sub>·CH<sub>2</sub>Cl<sub>2</sub>
作者:Robin B. Bedford、David E. Hibbs、Anthony F. Hill、Michael B. Hursthouse、K. M. Abdul Malik、Cameron Jones
DOI:10.1039/cc9960001895
日期:——
The reaction of [Ru(P=CHBu(t))Cl(CO)(CNC(6)H(3)Me(2)-2,6)(PPh(3))(2)] with HBF4 provides, rapidly and reversibly, the phosphaalkene complex [Ru(HP=CHBu(t))Cl(CO)(CNC(6)H(3)Me(2)-2,6)(PPh(3))(2)](+) which is converted by K[HF2] or [NBu(n)4]F to the structurally characterised fluorophosphine complex [Ru(PHFCH(2)Bu(t))Cl(CO)(CNC(6)H(3)Me(2)-2,6)(PPh(3))(2)](+).