The ruthenium(II) complexes
[(η6-C6Me6)RuH(P⌒O)][BF4]
(5a
−
c; P⌒O =
η2-(O,P)-chelated
ether−phosphine; a,
Ph2PCH2CH2OCH3;
b,
Ph2PCH2C4H7O2
(C4H7O2 = 1,3-dioxanyl);
c, Ph2PCH2C3H5O2
(C3H5O2 = 1,3-dioxolanyl)), each
having a Ru−O and Ru−H functionality, were
obtained by hydride abstraction from
(η6-C6Me6)RuH2(P∼O)
(4a
−
c, P∼O =
η1-(P)-coordinated
ligand) with Ph3CBF4. A facile Ru−O
bond cleavage occurs when 5a
−
c are
reacted with a
variety of small molecules. Carbon monoxide, acetonitrile,
tert-butyl isocyanide, and ethene
were readily added to 5a
−
c, leading
to the corresponding adducts
[(η6-C6Me6)RuH(P∼O)L][BF4] (6a
−
c,
7a
−
c,
8a
−
c,
10a
−
c; L = CO,
CH3CN, t-BuNC,
C2H4). π/σ rearrangements
with incorporation of the Ru−H bonds in
10a
−
c were not observed. If
5a
−
c were treated
with carbon disulfide, both functionalities were required. Rupture
of the Ru−O contact
resulted in a π-CS2-coordinated intermediate followed by
an insertion of CS2 into the Ru−H
bond to give the dithioformato complexes
[(η6-C6Me6)RuH(P∼O)(S2CH)][BF4]
(9a
−
c). All
compounds were obtained in excellent yields under mild conditions.
The structures of 5a,
7c, 8c, and 9a were determined by
single-crystal X-ray diffraction methods.
Ring-opening
metathesis polymerization of norbornene was achieved using complexes
5a
−
c as the catalyst
precursors.