om5012177_si_002.xyz (20.79 kB)
Ruthenaphosphaalkenyls: Synthesis, Structures, and Their Conversion to η2‑Phosphaalkene Complexes
dataset
posted on 2015-06-08, 00:00 authored by Victoria
K. Greenacre, Nicola Trathen, Ian R. CrossleyThe
ruthenaphosphaalkenyls [Ru{PCH(SiMe2R)}Cl(CO)(PPh3)2] (R = Me, Ph,
Tol) have been prepared in good yield by the facile hydroruthenation
of the respective phosphaalkynes, RMe2SiCP,
with [RuHCl(CO)(PPh3)3]; all three compounds
have been structurally characterized in the solid state. Complemented
by DFT studies of these, and the precedent [Ru{PCH(tBu)}Cl(CO)(PPh3)2], the
phosphaalkenyl moieties have been established unequivocally
to behave as one-electron donors to the coordinately unsaturated,
15-electron “RuCl(CO)(PPh3)2”
fragment, corroborating an earlier demonstration of nucleophilic character
at phosphorus within the tert-butyl system. Notwithstanding,
the ruthenaphosphaalkenyls are shown to react with the
nucelophiles Lipz′ (pz′ = pz, pz*, pzH,CF3, pzMe,CF3) to afford the η1,η2-chelated pyrazolylphosphaalkene
complexes [Ru{η1-N:η2-P,C-P(pz′)CH(R)}(CO)(PPh3)2], which feature a three-membered metallacyclic
(Ru–C–P) core. The nature of these novel compounds is
discussed, alongside preliminary insight into the process by which
they are formed.