Reactions of (PCP)Ru(CO)NHPh(PMe3) (PCP = 2,6-(CH 2PtBu2)2C6H3) with substrates that possess polar bonds

Article abstract of DOI:10.1021/ic0483592

The Ru(II) amido complex (PCP)Ru(CO)(PMe₃)(NHPh) (1) (PCP = 2,6-(CH₂P^tBU₂)₂C₆H ₃) reacts with compounds that possess polar C=N, C≡N, or C=O bonds (e.g., nitriles, carbodiimides,

Full text of DOI:10.1021/ic0483592

Inorg. Chem. 2005, 44, 2895−2907
Reactions of (PCP)Ru(CO)(NHPh)(PMe3) (PCP
with Substrates That Possess Polar Bonds
)
2,6-(CH2PtBu2)2C6H3)
Jubo Zhang,† T. Brent Gunnoe,*,† and Jeffrey L. Petersen‡
Department of Chemistry, North Carolina State UniVersity, Raleigh, North Carolina 27695-8204,
and C. Eugene Bennett Department of Chemistry, West Virginia UniVersity,
Morgantown, West Virginia 26506-6045
Received November 19, 2004
The Ru(II) amido complex (PCP)Ru(CO)(PMe3)(NHPh) (1) (PCP
that possess polar C N, C N, or C O bonds (e.g., nitriles, carbodiimides, or isocyanates) to produce four-
)
2,6-(CH2PtBu2)2C6H3) reacts with compounds
d
t
d
membered heterometallacycles that result from nucleophilic addition of the amido nitrogen to an unsaturated carbon
of the organic substrate. Based on studies of the reaction of complex 1 with acetonitrile, the transformations are
suggested to proceed by dissociation of trimethylphosphine, followed by coordination of the organic substrate and
then intramolecular N−C bond formation. In the presence of ROH (R ) H or Me), the fluorinated amidinate complex
(PCP)Ru(CO)(N(Ph)C(C6F5)NH) (6) reacts with excess pentafluorobenzonitrile to produce (PCP)Ru(CO)(F)(N(H)C-
(C6F5)NHPh) (7). The reaction with MeOH also produces o-MeOC6F4CN (>90%) and p-MeOC6F4CN (<10%). Details
of the solid-state structures of (PCP)Ru(CO)(F)(N(H)C(C6F5)NHPh) (7), (PCP)Ru(CO)[PhNC
{NH(hx)}N(hx)] (8),
(PCP)Ru(CO) N(Ph)C(NHPh)O (9), and (PCP)Ru(CO) OC(Ph)N(Ph) (10) are reported.
{
}
{
}
Introduction
complexes are possible intermediates in the hydroami-
nation of unsaturated C-C bonds as well as styrene oxida-
tive amination,13,14 rhodium amido systems are potential
intermediates in anti-Markovnikov hydroamination of viny-
larenes,15 and Co(III) hydroxide intermediates have been
reported to be important in catalytic hydrolysis of ni-
triles.16 Copper amido complexes have been used for the
polymerization of â-lactams, and copper alkoxides have
been reported to initiate the polymerization of carbodiim-
ides.17,18
Late transition metal complexes that possess amido,
alkoxide, or aryloxide ligands have been implicated in several
processes including the preparation of small molecules,
polymer synthesis, and biological transformations.1-10 For
example, Pd-catalyzed syntheses of arylamines and aryl
ethers proceed through Pd(II) arylamide or aryloxide inter-
mediates, respectively, and Pd(II) amido complexes can be
used for the preparation of polyanilines.5-7,11,12 Amido
The study of late transition metal complexes that possess
amido ligands has increased in the past decade with interest
in such systems derived, in part, from the opportunity to
access reactive fragments due to filled-filled interactions
* To whom correspondence should be addressed. E-mail:
brent_gunnoe@ncsu.edu.
† North Carolina State University.
‡ West Virginia University.
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10.1021/ic0483592 CCC: $30.25
Published on Web 03/19/2005
© 2005 American Chemical Society
Inorganic Chemistry, Vol. 44, No. 8, 2005 2895

Zhang et al.
that result from occupied dπ-manifolds.2,19,20 That is, for
metal systems that possess filled dπ orbitals, both π and π*
orbitals that result from overlap of the amido-based p-orbital
with a metal orbital of π-symmetry will be occupied and
reactive amido ligands are anticipated. Highly basic parent
amido ligands coordinated to tetraphosphine Ru(II) hydride
fragments have been reported,21-24 and this chemistry has
recently been extended to a parent amido complex of Fe(II)
that displays reactivity consistent with a basic and nucleo-
philic amido ligand as well as an 18-electron Ir(III) parent
amido complex.25-27 Holland et al. have recently reported
the synthesis and reactivity of three-coordinate Fe(II) amido
systems.28 In addition, amido complexes coordinated to Ru-
(II) systems that possess cyclopentadienyl or η6-arene ligands
have been reported.29-33
Scheme 1. Proposed Mechanism for the Formation of
(PCP)Ru(CO)(N(H)C(Me)NPh) (2) from the Reaction of
t
(PCP)Ru(CO)(PMe3)(NHPh) (1) with Acetonitrile (P ) Bu2P)
Results and Discussion
Our group has been interested in exploitation of late
transition metal amido complexes using the combination of
metal-based Lewis acidity and ligand-centered basicity/
nucleophilicity. We have prepared and studied a series of
Ru(II) and Cu(I) complexes that possess reactive amido
ligands,34-38 and recently we have reported that the five-
coordinate Ru(II) amido complex (PCP)Ru(CO)(NH2) (PCP
) 2,6-(CH2PtBu2)2C6H3) activates dihydrogen as well as
initiating intramolecular C-H activation of a t-Bu moiety
of the PCP ligand.39 Herein, the details of extension of our
studies with (PCP)Ru(II) amido systems to reactions of the
anilido complex (PCP)Ru(CO)(PMe3)(NHPh) (1) with com-
pounds that possess CdO, CdN, or CtN bonds are reported.
In addition, the reactivity of a PCP-Ru amidinate complex
with aromatic C-F bonds is disclosed.
Reaction of (PCP)Ru(CO)(PMe3)(NHPh) (1) with
Acetonitrile. As previously communicated,40 the Ru(II)
anilido complex (PCP)Ru(CO)(PMe3)(NHPh) (1) reacts with
acetonitrile to form the amidinate complex (PCP)Ru(CO)-
(N(Ph)C(Me)NH) (2) and free PMe3 (Scheme 1).40 Kinetic
studies at room temperature reveal that a likely reaction
pathway for amidinate formation involves initial dissociation
of PMe3, coordination of acetonitrile, and intramolecular
C-N bond formation (see below). The proposed mechanism
includes C-N bond formation that is initiated by the
combined Lewis acidity of Ru(II) and nucleophilicity of the
anilido ligand. In closely related reactions, Bercaw et al. have
reported the conversion of a scandium amido complex and
acetonitrile to yield a five-membered heterometallacycle,41
and a polyhedral borane has been reported to react with
ammonia in the presence of base and acetonitrile to yield an
amidinate moiety.42 Similar intramolecular nucleophilic bond
formations have been proposed in catalytic nitrile hydra-
tion,16,43 and addition reactions of coordinated nitriles have
been reviewed.44,45
(19) Holland, P. L.; Andersen, R. A.; Bergman, R. G. Comments Inorg.
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2000, 122, 8799-8800.
The rate of conversion of 1 and acetonitrile to complex 2
has been determined under various conditions, and the kinetic
studies are consistent with the proposed mechanism. The
anticipated rate law for the mechanism depicted in Scheme
1 is shown in eq 1. For reactions with 10 equiv of acetonitrile
(23) Fulton, J. R.; Sklenak, S.; Bouwkamp, M. W.; Bergman, R. G. J. Am.
Chem. Soc. 2002, 124, 4722-4737.
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k1k2[Ru][NCMe]
rate )
(1)
(27) Rais, D.; Bergman, R. G. Chem.sEur. J. 2004, 10, 3970-3978.
(28) Eckert, N. A.; Smith, J. M.; Lachicotte, R. J.; Holland, P. L. Inorg.
Chem. 2004, 43, 3306-3321.
k-1[PMe3] + k2[NCMe]
(29) Joslin, F. L.; Johnson, M. P.; Mague, J. T.; Roundhill, D. M.
Organometallics 1991, 10, 2781-2794.
and 10-25 equiv of PMe3, the rate of conversion of complex
(30) Boncella, J. M.; Eve, T. M.; Rickman, B.; Abboud, K. A. Polyhedron
1998, 17, 725-736.
(38) Jayaprakash, K. N.; Gunnoe, T. B.; Boyle, P. D. Inorg. Chem. 2001,
40, 6481-6486.
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Organometallics 2004, 23, 2724-2733.
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709-710.
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3094-3097.
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C.; Jackson, S. A.; Eisenstein, O.; Caulton, K. G. Inorg. Chem. 1994,
34, 488-499.
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Chem. 1990, 29, 4560-4565.
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P. S. J. Am. Chem. Soc. 2003, 125, 9435-9441.
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2896 Inorganic Chemistry, Vol. 44, No. 8, 2005

Reactions of (PCP)Ru(CO)(NHPh)(PMe3)
to be 3; however, small deviations in the slope can result in
substantial deviations for the y-intercept. Since k1 indicates
the rate of dissociation of PMe3 from complex 1, independent
studies of the rate of exchange of the coordinated PMe3 of
1 with free PMe3 provide an independent method for
determining k1. We have previously reported that the addition
of free PMe3 to a C6D6 solution of 1 results in line broadening
of phosphine resonances at elevated temperatures, and the
line broadening was attributed to phosphine exchange.40 The
addition of PMe3-d9 to a C6D6 solution of 1 at room
temperature results in the exchange of coordinated and free
PMe3 with an approximate half-life of 7 min. This corre-
sponds to a rate constant for dissociation of PMe3 of
approximately 1.7 × 10-3 s-1, which is 94 times greater than
the value of k1 calculated from the plot in Figure 1 and is a
reasonable value in consideration of the potentially substan-
tial error for the y-intercept.
Thus, the kinetic data provide evidence for the coordina-
tion of acetonitrile through exchange with PMe3 followed
by intramolecular N-C bond formation. A pathway involv-
ing intermolecular nucleophilic attack of the amido ligand
on uncoordinated acetonitrile is anticipated to exhibit a
reaction rate that is independent of PMe3 concentration
without evidence for saturation kinetics at higher concentra-
tions of acetonitrile. Indirect evidence for the proposed
reaction pathway comes from the complex (PCP)Ru(CO)-
(CNtBu)(NHPh) (see below). It was anticipated that the
isonitrile ligand would be less labile than PMe3, and
consistent with this notion and the proposal that the five-
coordinate complex (PCP)Ru(CO)(NHPh) is directly in-
volved in amidinate formation, a C6D6 solution of (PCP)-
Ru(CO)(CNtBu)(NHPh) and 20 equiv of NCMe shows no
evidence of reaction after 48 h. In contrast, under identical
conditions, complex 1 and NCMe are substantially converted
to the amidinate complex 2. At lower temperatures, an
intermolecular pathway for N-C bond formation may
become viable similar to a previously reported intermolecular
addition of a Ru(II) anilido ligand to CO2.46
Figure 1. Plot of 1/kobs versus [PMe3]/[NCMe] for the conversion of
complex 1 and NCMe to complex 2 (R2 ) 0.99).
1 and acetonitrile to the amidinate complex 2 is inverse first-
order in concentration of PMe3 (see the Supporting Informa-
tion). Under these reaction conditions, no evidence of
PCP-Ru species other than complex 1 and complex 2 was
observed during the kinetic experiments. These results are
consistent with the term in the denominator k-1[PMe3]
dominating the term k2[NCMe] under the specific conditions
of these experiments with kobs under pseudo-first-order
conditions being equal to k1k2[NCMe]/k-1[PMe3].
A plot of kobs versus the concentration of NCMe for
reactions with 10 equiv of PMe3 and between 10 and 50
equiv of NCMe reveals a first-order dependence on the
concentration of NCMe at low concentrations of NCMe
while saturation kinetics are apparent at higher concentrations
(see the Supporting Information). Thus, in agreement with
the observation of an inverse dependence of reaction rate
on concentration of PMe3 at lower concentrations of NCMe,
the term k-1[PMe3] is greater than k2[NCMe] with the
pseudo-first-order rate constant equal to k1k2[NCMe]/
k-1[PMe3]. At elevated concentrations of NCMe, the term
k2[NCMe] becomes greater than k-1[PMe3] with kobs inde-
pendent of the concentration of NCMe.
These results suggest that at higher concentrations of
NCMe, the rate of formation of complex 2 should be
independent of the concentration of PMe3. Monitoring the
rate of disappearance of complex 1 in the presence of 100
equiv of acetonitrile with 10, 15, or 20 equiv of PMe3 reveals
that kobs is independent of PMe3 concentration and is equal
to 1.29(7) × 10-5 s-1. In addition, the magnitude of kobs is
similar to that for the reaction with 10 equiv of PMe3 and
50 equiv of NCMe (kobs ) 9.6 × 10-6). For reactions in the
presence of a large excess of NCMe, some decomposition
was observed (∼10%) toward the latter portions of the
reaction. Dissolution of the amidinate complex 2 in CD3CN
reveals that 2 undergoes relatively slow decomposition in
the presence of excess nitrile.
Reactions of 1 with Nitriles. The formation of amidinate
complex 2 upon combination of 1 with acetonitrile can be
extended to other nitriles. For example, the reactions of
complex 1 and benzonitrile, p-fluorobenzonitrile, or p-
tolunitrile at room temperature produce the corresponding
amidinate complexes 3, 4, and 5 in 48%, 49%, and 52%
isolated yield, respectively (eq 3). IR spectroscopy of all three
For reactions that are pseudo-first-order in concentration
of 1, rearrangement of the rate law shown in eq 1 indicates
that a plot of 1/kobs versus [PMe3]/[NCMe] should be linear
with the slope equal to k-1/k1k2 and the y-intercept equal to
1/k1 (eq 2). From the plot shown in Figure 1, k1 was estimated
amidinate complexes reveals νCO ) 1898 cm-1 with νNH
ranging from 3342 to 3348 cm-1. Although NMR spectros-
copy indicates the selective formation of a single isomer for
k-1[PMe3]
1
k1
1/kobs
)
+
(2)
k1k2[NCMe]
to be 1.8 × 10-5 s-1, and using the value of k1 and the slope
from the plot in Figure 1, the ratio of k-1/k2 was calculated
(46) Hartwig, J. F.; Bergman, R. G.; Andersen, R. A. J. Am. Chem. Soc.
1991, 113, 6499-6508.
Inorganic Chemistry, Vol. 44, No. 8, 2005 2897

Zhang et al.
each product, the stereochemistry of 3-5 has not been
determined; however, we presume that the NH of the
amidinate ligand is trans to the Ru-CO bond as is observed
for the methyl amidinate complex (PCP)Ru(CO)(N(Ph)C-
(Me)NH) (2).40 Attempted reactions of 1 with pentafluo-
robenzonitrile or p-nitrobenzonitrile result in decomposition
to multiple products. Although we were unable to isolate
and characterize the decomposition products, the change in
reactivity could be due to initial nucleophilic addition of the
amido group to the electron-deficient aromatic system rather
than reaction at the nitrile moiety.
The reaction of 2 with C6F5CN at room temperature
produces the amidinate complex (PCP)Ru(CO)(N(Ph)C-
(C6F5)NH) (6) in 70% isolated yield (eq 4). The production
Figure 2. ORTEP of (PCP)Ru(CO)(F)(N(H)C(C6F5)NHPh) (7) (30%
probability). Selected bond lengths (Å) and angles (deg): Ru-F1,
2.106(2); N1-C2, 1.286(3); N2-C2, 1.342(4); C2-N1-Ru1, 131.1(2);
N1-C2-N2, 121.0(3).
Chart 1. Observed H-F Coupling Is Consistent with Intramolecular
Hydrogen Bonding
of 6 is irreversible between room temperature and 90 °C as
indicated by the failure of 6 to react with NCMe to produce
2 and C6F5CN. The failure of 1 and C6F5CN to produce 6
suggests that the conversion of complex 2 and C6F5CN to
produce (PCP)Ru(CO)(N(Ph)C(C6F5)NH) (6) does not likely
occur through the formation of (PCP)Ru(CO)(NHPh) and
free acetonitrile as previously suggested.40 In addition, the
reversibility of formation of amidinate complex 2 indicated
by the conversion of 2 and C6F5CN to 6 is not general. The
combination of complex 2 with excess benzonitrile, p-
fluorobenzonitrile, or p-tolunitrile in C6D6 at 90 °C results
in a minor amount of decomposition after 24 h without
observation of complex 3, 4, or 5, respectively (eq 4). In
addition, the reaction of p-tolunitrile with complex 3 in a
C6D6 solution does not yield observable quantities of complex
5 after 24 h at 90 °C. The electronic similarity of complexes
3 and 5 suggests that the failure of complex 3 and
p-tolunitrile to convert to complex 5 and benzonitrile is likely
due to kinetic factors.
A single crystal of 7 was obtained, and the solid-state
structure was solved by X-ray crystallography (Figure 2).
Table 1 presents selected crystallographic data and collection
parameters. The X-ray structure reveals that the fluoride
ligand is trans to CO. The N1-C2 and N2-C2 bond
distances of 1.286(3) and 1.342(4) Å are consistent with a
carbon-nitrogen double bond and a bond order that is
intermediate between a single and double bond, respectively.
Consistent with solution NMR spectroscopy, the N2-H2
bond is oriented to form an intramolecular hydrogen bond
with the fluoride ligand.
The formation of complex 7 occurs through the net
addition of HF to the amidinate complex (PCP)Ru(CO)-
(N(H)C(C6F5)NPh) (6). The activation of C-F bonds has
attracted considerable attention due to potential synthetic
utility as well as importance for waste remediation;52-54
however, the inherent strength of C-F bonds presents a
substantial challenge to the development of such methodolo-
gies. The use of transition metal complexes is a promising
strategy with metal-mediated C-F activations reported to
proceed by oxidative addition, σ-bond metathesis, electron
Reaction of 6 with Fluorinated Aromatic Compounds.
In the absence of other reactive substrates, complex 6 is
stable at room temperature under inert atmosphere in C6D6.
In the presence of excess C6F5CN at room temperature, the
perfluorophenyl amidinate complex 6 reacts to form (PCP)-
Ru(CO)(F)(N(H)C(C6F5)NHPh) (7) in 80% isolated yield.
1H NMR features of 7 include a doublet at 12.7 ppm due to
the amino hydrogen with JHF ) 62 Hz, and 19F NMR
spectroscopy reveals a doublet of triplets at -11.3 ppm with
JHF ) 62 and JPF ) 17 Hz. The observation of H-F coupling
indicates the presence of hydrogen bonding between the
fluoride ligand and the hydrogen atom of the NHPh moiety
(Chart 1). Reports of intramolecular H‚‚‚F hydrogen bonding
are relatively uncommon for transition metal complexes;47-51
however, closely related Ir-F‚‚‚H-N hydrogen bonds have
(47) Peris, E.; Lee, J. C., Jr.; Rambo, J. R.; Eisenstein, O.; Crabtree, R. H.
J. Am. Chem. Soc. 1995, 117, 3485-3491.
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13106.
(49) Murphy, V. J.; Hascall, T.; Chen, Y. J.; Parkin, G. J. Am. Chem. Soc.
1996, 118, 7428-7429.
(50) Esteruelas, M. A.; Oliva´n, M.; On˜ate, E.; Ruiz, N.; Tajada, M. A.
Organometallics 1999, 18, 2953-2960.
(51) den Reijer, C. J.; Wo¨rle, M.; Pregosin, P. S. Organometallics 2000,
19, 309-316.
(52) Kiplinger, J. L.; Richmond, T. G.; Osterberg, C. E. Chem. ReV. 1994,
94, 373-431.
1
(53) Murphy, E. F.; Murugavel, R.; Roesky, H. W. Chem. ReV. 1997, 97,
3425-2468.
been reported with JHF ) 52, 84 Hz as well as an
intramolecular Ru-F‚‚‚H-O hydrogen bond with 1JHF ) 66
(54) Burdeniuc, J.; Jedlicka, B.; Crabtree, R. H. Chem. Ber. 1997, 130,
145-154.
Hz.47,48,51
2898 Inorganic Chemistry, Vol. 44, No. 8, 2005

Reactions of (PCP)Ru(CO)(NHPh)(PMe3)
Table 1. Selected Crystallographic Data and Collection Parameters for Complexes 7-10
complex
(PCP)Ru(CO)[PhNC{NH(hx)}-
(PCP)Ru(CO)(F)(N(H)C(C6F5)-
(PCP)Ru(CO){N(Ph)C-
(NHPh)O} (9)
(PCP)Ru(CO){OC(Ph)-
N(Ph)} (10)
NHPh) (7)
N(hx)] (8)
empirical formula
formula wt
cryst syst
space group
a, Å
b, Å
c, Å
C38H50F6N2OP2Ru
827.81
monoclinic
P21/n
9.0368(5)
20.0690(10)
21.0286(10)
90
98.292(1)
90
3773.9(3)
4
1.457
0.0431, 0.1042
1.027
C44H75N3OP2Ru
825.08
monoclinic
C2/c
44.327(10)
10.868(2)
21.270(5)
90
116.770(3)
90
9149(4)
8
1.198
0.0761, 0.1363
0.931
C38H54N2O2P2Ru
733.84
triclinic
C38H53NO2P2Ru
718.82
monoclinic
P21/c
16.4184(9)
11.5064(6)
20.7716(11)
90
109.963(1)
90
3688.3(3)
4
1.295
0.0502, 0.1184
0.986
P1h
13.2370(8)
14.0281(8)
21.1699(16)
79.378(2)
74.244(1)
89.938(1)
3713.5(4)
4
R, deg
â, deg
γ, deg
V (Å3)
Z
Dcalcd, g cm-3
R1, wR2 (I > 2σ(I))
GOF
1.313
0.0587, 0.1112
0.967
Scheme 2. Reactions of Complex 6 that Produce
(PCP)Ru(CO)(F)(N(H)C(C6F5)NHPh) (7)
transfer, radical chain pathways, R- and â-fluoride elimina-
tions, and reductive defluorination.55-62 Although the fluoride
ligand of 7 was clearly derived from C6F5CN, the source of
H+ was uncertain. Monitoring the rate of the formation of
complex 7 in various solvents (benzene, methylene chloride,
tetrahydrofuran, and pentane) produced inconsistent kinetics
and percent yield even when solvent identity was held
constant. For example, multiple reactions of complex 6 with
C6F5CN in C6D6 revealed that the half-life for the formation
of complex 7 varied between 5 and 24 h. These results
suggested the possibility of an impurity catalyzing the
reaction or serving as a reactant. The role of adventitious
water was tested by comparing the reactions of (PCP)Ru-
(CO)(N(H)C(C6F5)NPh) with C6F5CN in rigorously dried
C6D6 (twice distilled from CaH2 under dinitrogen and stored
over molecular sieves) versus C6D6 with 10 equiv (based
on the concentration of complex 6) of H2O added. In the
absence of H2O, only minimal formation of 7 (<5%) was
observed after 12 h at room temperature. In contrast, the
addition of 10 equiv of H2O resulted in quantitative produc-
tion of 7 after 12 h at room temperature (Scheme 2). The
dependence of the reaction on the presence of H2O is
consistent in all four solvents listed above and indicates that
the source of proton for the formation of 7 is likely H2O.
Unfortunately, the identification of organic products that
accompany the formation of complex 7 upon reaction of 6
with C6F5CN and H2O is complicated by the formation of
multiple compounds in low concentrations.
with H2O, the formation of o-MeOC6F4CN (>90%) and
p-MeOC6F4CN (<10%) is readily identified from the reaction
with MeOH. Unfortunately, a previously reported competi-
tive nucleophilic addition of methoxide to the nitrile carbon
of C6F5CN complicates a detailed kinetic analysis of this
reaction.63 In control experiments, C6F5CN does not react
with MeOH at 70 °C for at least 1 day, and C6D6 solutions
of MeOH with (PCP)Ru(CO)(N(H)C(C6F5)NPh) at room
temperature show no reaction for at least 48 h.
We propose that (PCP)Ru(CO)(N(H)C(C6F5)NPh) medi-
ates nucleophilic displacement of fluoride by methoxide with
the Ru complex serving as a reservoir for proton (basic
amidinate ligand) and fluoride (Lewis acidic metal). The
Ru(II) complex could bind and activate C6F5CN toward
nucleophilic attack by free MeOH or deprotonate methanol
to promote methoxide addition to free C6F5CN. However,
we suggest that a more likely reaction pathway is simulta-
neous activation of MeOH and C6F5CN by the metal center
similar to the depiction in Scheme 3. The failure of complex
6 to react with MeOH at room temperature indicates that
deprotonation of MeOH to form discrete methoxide ion is
an unlikely reaction pathway (the formation of small quanti-
ties of thermally disfavored methoxide is still possible). Most
importantly, the selective substitution at the ortho position
suggests that the metal center interacts with C6F5CN during
the substitution since simple nucleophilic displacement of
The addition of 10 equiv of MeOH to a dry C6D6 solu-
tion of (PCP)Ru(CO)(N(H)C(C6F5)NPh) (6) with 10 equiv
of C6F5CN quantitatively produces complex 7 during a
period of 5 h at room temperature. In contrast to the reaction
(55) Jones, W. D. J. Chem. Soc., Dalton Trans. 2003, 3991-3995.
(56) Aizenberg, M.; Milstein, D. Science 1994, 265, 359-361.
(57) Aizenberg, M.; Milstein, D. J. Am. Chem. Soc. 1995, 117, 8674-
8675.
(58) Braun, T.; Perutz, R. N. Chem. Commun. 2002, 2749-2757.
(59) Hughes, R. P.; Smith, J. M. J. Am. Chem. Soc. 1999, 121, 6084-
6085.
(60) Watson, L. A.; Yandulov, D. V.; Caulton, K. G. J. Am. Chem. Soc.
2001, 123, 603-611.
(61) Albietz, P. J., Jr.; Houlis, J. F.; Eisenberg, R. Inorg. Chem. 2002, 41,
2001-2003.
(62) Harrison, R. G.; Richmond, T. G. J. Am. Chem. Soc. 1993, 115, 5303-
5304.
(63) Bolton, R.; Sandall, J. P. B. J. Chem. Soc., Perkin Trans. 2 1978,
1288-1292.
Inorganic Chemistry, Vol. 44, No. 8, 2005 2899

Zhang et al.
Scheme 3. Proposed Pathway for Regioselective Substitution of the
Aromatic C-F Bond of C6F5CN by Methoxide
cyano group due to reduced steric profile of cyano versus
fluoride. Analysis of the reaction of KOtBu with C6F5CN
by 19F NMR spectroscopy indicates that the para-substituted
compound (p-tBuOC6F4CN) is produced in about 70% yield
while the ortho-substituted compound (o-tBuOC6F4CN) is
produced in about 20% yield. Given that the bulky nucleo-
phile t-butoxide exhibits a preference for para attack over
ortho selectivity, it is likely that the pathway shown in
Scheme 3 better explains the Ru-mediated selectivity.
For the reaction of 6 with MeOH, replacement of the cyano
group with a nitro group results in nucleophilic substi-
tution with opposite regioselectivity (Scheme 2). The com-
bination of C6F5NO2, MeOH, and (PCP)Ru(CO)(N(H)C-
(C6F5)NPh) at room temperature yields complex 7 (quanti-
tative by NMR spectroscopy), p-MeOC6F4NO2 (>90%), and
o-MeOC6F4NO2 (<10%). The change in regioselectivity is
possibly explained by the poor coordinating ability of the
nitro group in comparison with the nitrile group of C6F5CN.
Coordination of the nitro group of C6F5NO2 might not occur
during the nucleophilic substitution since the reaction of free
methoxide with C6F5NO2 also yields p-MeOC6F4NO2;64 how-
ever, the metal center is clearly involved in the overall
transformation since MeOH does not react with C6F5NO2 in
the absence of (PCP)Ru(CO)(N(H)C(C6F5)NPh). Nucleo-
philic substitution is not observed when either C6F5OMe or
C6F6 is added to (PCP)Ru(CO)(N(H)C(C6F5)NPh) (6) and
MeOH (eq 6), and the qualitative reactivity pattern is
fluoride from C6F5CN by alkoxide nucleophiles is highly
regioselective for substitution at the position para to the cyano
group.63,64 In addition, attack of free methoxide on coordi-
nated C6F5CN would be expected to enhance the para
selectivity. The small amount of p-MeOC6F4CN likely forms
from the addition of free methoxide to coordinated perfluo-
robenzonitrile or addition of activated methanol to free
perfluorobenzonitrile (Scheme 3, “alternative route”). Analo-
gous ortho selectivity has been reported for the reaction of
a fluorinated phosphine bound to Pt(II) with hydroxide, Rh-
catalyzed silylation of 2,3,4,5,6-pentafluoroacetophenone,
and Rh-mediated C-F activation of pentafluoroanisole under
photolytic conditions.65-67 The addition of base to complex
7 at room temperature results in the net removal of HF and
regeneration of (PCP)Ru(CO)(N(H)C(C6F5)NPh) (eq 5). This
consistent with Hammett values for the different substituents
indicating that an electron-withdrawing group on the per-
fluorophenyl ring is necessary to observe the nucleophilic
displacement (e.g., σp/σo: NO2, 0.78/0.71; CN, 0.66/0.56;
F, 0.06/0.34; OCH3, -0.27/0.12).69 The reactivity trend is
also consistent with an electron-transfer pathway; however,
the regioselectivity of methoxide substitution of fluoride to
produce o-MeOC6F4CN is inconsistent with an initial redox
event.70
Reactions of 1 with Carbodiimide, Isocyanate, Carbox-
amides, Benzaldehyde, and t-Butylisonitrile. Having ob-
served metal-mediated N-C bond formation with nitriles,
we became interested in extending N-C bond formation to
other polar multiple bonds. Transition metal amido com-
plexes have been reported to initiate the polymerization of
carbodiimides, and it has been proposed that the mechanism
for polymer formation involves coordination of the carbo-
diimide followed by intramolecular nucleophilic attack of a
nitrogen-based ligand on the carbodiimide carbon.18,71 The
reaction of complex 1 and di-n-hexylcarbodiimide produces
free trimethylphosphine and (PCP)Ru(CO)[PhNC{NH(hx)}-
1
reaction is quantitative by H, 31P, and 19F NMR spectros-
copy.
Although the A values for fluoride and cyanide groups
are almost identical,68 a potential alternative explanation for
the observed regioselectivity of methoxide/fluoride substitu-
tion is steric control over ortho versus para selectivity. The
activation of MeOH by the Ru(II) complex could result in a
bulky nucleophile, and steric differentiation between para-
and ortho-selective fluoride displacement could guide attack
to the ortho position. In this scenario, the interaction of the
basic amidinate ligand of complex 6 with MeOH would
generate a sterically hindered nucleophile, and the C-F
substitution reaction would occur at the position ortho to the
(64) Banks, R. E. Fluorocarbons and their DeriVatiVes; MacDonald and
Company, 1970.
(65) Park, S.; Pontier-Johnson, M.; Roundhill, D. M. J. Am. Chem. Soc.
1989, 111, 3101-3103.
(66) Ishii, Y.; Chatani, N.; Yorimitsu, S.; Murai, S. Chem. Lett. 1998, 157-
158.
(67) Ballhorn, M.; Partridge, M. G.; Perutz, R. N.; Whittlesey, M. K. Chem.
Commun. 1996, 961-962.
(68) Hirsch, J. A. In Topics in Stereochemistry; Allinger, N. L., Eliel, E.
L., Eds.; Interscience Publishers: New York, 1967; Vol. 1, pp 199-
222.
(69) Hansch, C.; Leo, A.; Taft, R. W. Chem. ReV. 1991, 91, 165-195.
(70) Hintermann, S.; Pregosin, P. S.; Ruegger, H.; Clark, H. C. J.
Organomet. Chem. 1992, 435, 225-234.
(71) Goodwin, A.; Novak, B. M. Macromolecules 1994, 27, 5520-5522.
2900 Inorganic Chemistry, Vol. 44, No. 8, 2005

Reactions of (PCP)Ru(CO)(NHPh)(PMe3)
Scheme 4. Reactions of Complex 1 with Substrates that Possess Polar C-X (X ) O or N) Multiple Bondsa
a Unless otherwise noted, reactions were performed at room temperature.
N(hx)] (8) (hx ) hexyl) (Scheme 4). Complex 8 is produced
at room temperature within 30 min and is isolated in 41%
yield. A closely related series of reactions has been reported
for cis-(PMe3)4Ru(H)(NH2);24 however, the final products
for the tetraphosphine system are η1-guanidinate complexes.
Similarly, reaction of Cp*Ir(PMe3)(Ph)(NH2) with diisopro-
pylcarbodiimide yields an η1-guanidinate complex,27 and
the combination of (bpy)Re(CO)3(NHp-tol) with (p-tol)-
NdCdS yields the analogous sulfur-coordinated product
(Cp* ) pentamethylcyclopentadienyl, p-tol ) para-tolyl, and
bpy ) 2,2′-bipyridine).72 For the {(PCP)Ru(CO)} fragment,
the lability of PMe3 allows the formation of a κ2-guanidinate
ligand. The resonance due to the amino hydrogen was not
Figure 3. ORTEP of (PCP)Ru(CO)[PhNC{NH(hx)}N(hx)] (8) (30%
located in the 1H NMR spectrum of complex 8 likely due to
probability). Selected bond lengths (Å) and angles (deg): Ru1-C1, 1.784-
(8); Ru1-N1, 2.197(6); Ru1-N2, 2.212(6); N2-C26, 1.300(9); N1-C26,
1.346(9); N3-C26, 1.383(10); N3-C39, 1.459(10); N1-Ru1-N2, 59.8-
(2); Ru1-N2-C33, 139.1(5); Ru1-N1-C27, 132.2(5); N2-C26-N3,
124.7(7); N2-C26-N1, 112.4(7); N1-C26-N3, 122.9(7).
overlap with other resonances.
A single-crystal X-ray diffraction study of complex 8 has
confirmed its identity (Figure 3). Table 1 presents crystal-
lographic data and collection parameters. The coordination
geometry is pseudo-octahedral with the P1-Ru-P2 angle
of 157.05(7)°. The Ru-N1 bond distance (2.197(6) Å) is
slightly shorter than the Ru-N2 distance (2.212(6) Å). The
two amidinate N-C bond distances are similar (1.346(9)
vs 1.300(9) Å), and the C26-N3-C39 bond angle of
122.6(7)° is also consistent with N3-C26 double bond
character. The N3-C26 bond distance of 1.383(10) Å reveals
some multiple bonding between the amino group and the
guanidinate carbon.
likely forms upon coordination of the isocyanate (through
ligand exchange with PMe3) followed by N-C bond forma-
tion. Subsequent proton transfer and possible rearrangement
would yield complex 9 (Scheme 5).
The solid-state structure of 9 reveals two independent
molecules in the unit cell. In both structures the N-H bond
of the NHPh amino group is anti with respect to the C-O
bond of the amidate ligand. In one structure, the phenyl group
is oriented toward the NPh moiety of the amidate ligand,
while the phenyl group of the NHPh is oriented toward the
amidate oxygen in the second structure. One of the two
independent structures is shown in Figure 4, and Table 1
lists crystallographic data and collection parameters. The
coordination sphere is pseudo-octahedral with the amidate
oxygen trans to the Ru-CO bond. Both N-C bond dis-
tances (1.317(5) and 1.383(5) Å) are shorter than N-C single
bonds, indicating a competition for π-interaction. The
The amido complex can also initiate C-N bond formation
with substrates that possess C-O multiple bonds. For
example, the reaction of (PCP)Ru(CO)(PMe3)(NHPh) with
phenylisocyanate produces (PCP)Ru(CO){N(Ph)C(NHPh)O}
(9) in 44% isolated yield at room temperature. Complex 9
(72) Hevia, E.; Pe´rez, J.; Riera, V.; Miguel, D. Organometallics 2003, 22,
257-263.
Inorganic Chemistry, Vol. 44, No. 8, 2005 2901

Zhang et al.
Figure 4. ORTEP of (PCP)Ru(CO){N(Ph)C(NHPh)O} (9) (30% prob-
ability). Selected bond lengths (Å) and angles (deg): Ru2-O3, 2.261(3);
Ru2-N3, 2.208(3); N3-C64, 1.317(5); O3-C64, 1.274(5);, Ru2-C39,
1.787(5); Ru2-N3-C65, 139.7(3); Ru2-N3-C64, 92.6(3); Ru2-O3-
C64, 91.4(3); N3-C64-O3, 116.6(4); N3-C64-N4, 123.1(4); O3-C64-
N4, 120.3(4); C64-N4-C71, 128.5(4).
Figure 5. ORTEP of (PCP)Ru(CO){OC(Ph)N(Ph)} (10) (30% probability).
Selected bond lengths (Å) and angles (deg): Ru1-C1, 1.787(5); Ru1-
N1, 2.186(3); Ru1-O2, 2.206(2); N1-C26, 1.311(5); O2-C26, 1.283(4);
C26-C27, 1.500(5); Ru1-N1-C33, 135.4(2); Ru1-N1-C26, 92.8(2);
Ru1-O2-C26, 92.7(2); O2-C26-N1, 114.8(3); N1-C26-C27, 126.5-
(4); O2-C26-C27, 118.6(3).
Scheme 5. Possible Pathway for the Conversion of
(PCP)Ru(CO)(NHPh)(PMe3) (1) and Phenylisocyanate to
(PCP)Ru(CO){N(Ph)C(NHPh)O} (9)
Table 1). Similar to complex 9, the amidate oxygen is trans
to the Ru-CO bond. The amidate N1-C26 bond distance
of complex 10 (1.311(5) Å) is statistically identical to the
analogous bond of complex 9 (1.317(5) Å), and the
C26-C27 bond distance of 1.500(5) Å is close to the value
for a C-C single bond.
The amidate complexes 10 and 11 do not react with free
amine NH2R to initiate “NR” metathesis reactions. For exam-
ple, a solution of excess aniline and (PCP)Ru(CO){OC(Me)-
N(Me)} (11) showed no observed reaction after 2 days at
room temperature, and only minor decomposition was ob-
served after heating to 90 °C for 24 h without formation of
(PCP)Ru(CO){OC(Me)N(Ph)} or methylamine (Scheme 4).
Complex 1 also initiates N-C bond formation with
carbonyl groups of aldehydes. For example, the reaction of
(PCP)Ru(CO)(PMe3)(NHPh) with benzaldehyde produces the
amidate complex (PCP)Ru(CO){OC(Ph)N(Ph)} (10) (Scheme
4). The transformation results in the net removal of dihy-
drogen from the amido complex (PCP)Ru(CO)(PMe3)-
(NHPh) and benzaldehyde. In addition to the formation of
complex 10 (40%), free PCPH is produced in approximately
30% yield along with the Ru(II) hydride complexes (PCP)-
Ru(CO)(PMe3)H (12) (10%) and (PCP)Ru(CO)H (5%) as
well as a small amount of an uncharacterized species
(observed by 31P NMR spectroscopy). The hydride complex
(PCP)Ru(CO)H has been previously reported,75 and the
identity of complex 12 was confirmed by independent
preparation and characterization (eq 7). The phosphorus-
C64-N4-C71 bond angle of 128.5(4)° is consistent with
N-C double bond character. Details of the second structure
can be found in the Supporting Information.
The use of transition metal complexes as catalysts for the
amine/carboxamide transamidation has recently been re-
ported.73 Although detailed mechanistic studies have not been
reported, it was suggested that activation of the carboxamide
by the Lewis acidic metal in combination with a nucleophilic
amide ligand might be important for catalytic activity. Thus,
we explored the reaction of complex 1 with carboxamides.
The combination of (PCP)Ru(CO)(PMe3)(NHPh) and 1 equiv
of benzanilide or N-methylacetamide at room temperature
converts quantitatively to free aniline and the amidate
complexes (PCP)Ru(CO){OC(Ph)N(Ph)} (10) and (PCP)-
Ru(CO){OC(Me)N(Me)} (11) (Scheme 4). Complexes 10
and 11 are isolated in 55% and 50% yield, respectively. In
a similar set of transformations, Shafer et al. have recently
reported the conversion of Ti and Zr amido complexes to
amidate complexes upon reaction with carboxamides.74 The
structure of the amidate complex 10 has been determined
by a single-crystal X-ray diffraction study (Figure 5 and
hydrogen coupling constants of 12 suggest that the PMe3
and hydride ligands are in a cis orientation (see Experimental
Section).
(73) Eldred, S. E.; Stone, D. A.; Gellman, S. H.; Stahl, S. S. J. Am. Chem.
Soc. 2003, 125, 3422-3423.
(74) Li, C.; Thomson, R. K.; Gillon, B.; Patrick, B. O.; Schafer, L. L. Chem.
Commun. 2003, 2462-2463.
(75) Gusev, D. G.; Dolgushin, F. M.; Antipin, M. Y. Organometallics 2000,
19, 3429-3434.
2902 Inorganic Chemistry, Vol. 44, No. 8, 2005

Reactions of (PCP)Ru(CO)(NHPh)(PMe3)
Scheme 6. Preparation of Ru(II) Hydroxide Complexes
Scheme 7. Reactions that Produce (PCP)Ru(CO)(CNtBu)(OH) (16)
Although the detailed mechanism of the transformation
of complex 1 and benzaldehyde has not been determined,
the reaction bears some similarity to the organic reaction of
aromatic aldehydes with strong bases (e.g., NaOH) to
produce an alcohol and carboxylate (i.e., the Cannizzaro
reaction).76
isolated in 95% yield upon reaction of (PCP)Ru(CO)(OH)
(14) with CNtBu at room temperature. The stereochemistry
of 16 has not been determined.
Summary and Conclusions
The combination of complex 1 and t-BuNC at room
temperature results initially in a ligand exchange to produce
(PCP)Ru(CO)(CNtBu)(NHPh) (13) and free PMe3 (Scheme
4). Complex 13 has been isolated in 41% yield. The
stereochemistry of complex 13 has not been determined. As
discussed above, NMR spectroscopy reveals no evidence of
reaction between complex 13 and excess NCMe after 48 h
at room temperature. Heating complex 13 in C6D6 to 90 °C
does not result in observable reactivity between the amido
and isonitrile ligands; rather, the formation of a previously
reported cyclometalated species and free aniline is observed
(Scheme 4).39 The cyclometalated complex is in equilibrium
with a second complex that likely results from coordination
of t-BuNC.
Ru(II) Hydroxide Complex. If reaction conditions are
not carefully controlled, several of the complexes discussed
herein are observed to undergo transformation to a new
complex. Anticipating the possible involvement of water
leading to the formation of a Ru(II) hydroxide complex, we
prepared (PCP)Ru(CO)(OH) (14) (92% isolated yield) upon
reaction of (PCP)Ru(CO)Cl with CsOH at room tempera-
ture (Scheme 6). The reaction of 14 with PMe3 at room
temperature cleanly generates the octahedral complex (PCP)-
Ru(CO)(PMe3)(OH) (15) (97% isolated yield; Scheme 6).
The conversion of 14 to 15 results in an upfield shift for the
resonance of the hydroxyl proton from 3.85 to -4.42 ppm.
The upfield chemical shift of 15 relative to 14 is consistent
with the disruption of hydroxide to Ru π-donation upon
conversion from a five-coordinate Ru(II) complex to an
octahedral 18-electron system since the inability of the
hydroxide ligand to π-donate to Ru(II) for complex 15 likely
increases electron-density at the hydroxide moiety. Examples
of transformations that produce (PCP)Ru(II) hydroxide
complexes include reaction of the anilido complex (PCP)-
Ru(CO)(PMe3)(NHPh) (1) with water to produce complex
15 and the addition of water to (PCP)Ru(CO)(CNtBu)(NHPh)
(13) to yield (PCP)Ru(CO)(CNtBu)(OH) (16) (Schemes 6
and 7). Complex 16 has been independently prepared and
The octahedral Ru(II) complex (PCP)Ru(CO)(PMe3)-
(NHPh) (1) reacts with a range of substrates to initiate N-C
bond formations that produce aza-metallacycles. Although
the kinetic details of each reaction have not been probed,
we suggest that the reaction pathways are likely to be
analogous to the reaction of the anilido complex and
acetonitrile with trimethylphosphine dissociation, substrate
coordination, and intramolecular nucleophilic attack of the
amido nitrogen at the â-carbon of the coordinated substrate.40
These transformations demonstrate the feasibility of using
metal-centered Lewis acidity in combination with the nu-
cleophilicity at the amido ligand to mediate control of N-C
bond-forming reactions. Consistent with the suggested
reactivity patterns, the coordination of tert-butyl isonitrile
to the fragment (PCP)Ru(CO)(NHPh) does not produce
subsequent reactivity since intramolecular nucleophilic attack
would result in Namido addition to an electron-rich nitrogen
of the isonitrile ligand. Such reactions could ultimately
provide methodologies for controlled N-C bond forming
transformations.
Experimental Section
General Methods. All procedures were performed under an
atmosphere of dinitrogen in a glovebox or using standard Schlenk
techniques. Oxygen levels were <15 ppm for glovebox manipula-
tions. Benzene and tetrahydrofuran were distilled from sodium/
benzophenone. Pentane and methanol were distilled from P2O5.
Acetonitrile was distilled from P2O5 followed by distillation from
CaH2. Methylene chloride was purchased as an OptiDry solvent
(<50 ppm H2O) and passed through two columns of activated
alumina prior to use. All solvent manipulations were performed
under an atmosphere of dinitrogen. C6D6, CD2Cl2, and CDCl3 were
degassed via three freeze-pump-thaw cycles and stored over 4
1
Å molecular sieves. H and 13C NMR measurements were per-
formed on either a Varian Mercury 300 or 400 MHz spectrometer
and referenced to TMS using resonances due to residual protons
in the deuterated solvents or the 13C resonances of the deuterated
solvents. All 31P NMR spectra were recorded on a Varian Mercury
instrument operating at a frequency of 161 MHz with 85%
phosphoric acid (0 ppm) as external standard. All 19F spectra were
recorded on a Varian Mercury instrument operating at a frequency
of 376.5 MHz with CF3CO2H (-78.5 ppm) as external standard.
(76) March, J. AdVanced Organic Chemistry: Reactions, Mechanisms, and
Structure, 4th ed.; John Wiley and Sons: New York, 1992.
Inorganic Chemistry, Vol. 44, No. 8, 2005 2903

Zhang et al.
GC-MS was performed using a HP GCD system with a 30 m ×
0.25 mm HP-5 column with 0.25 µm film thickness. IR spectra
were acquired using a Mattson Genesis II FT-IR as solutions in a
KBr solvent cell. Elemental analyses were conducted by Atlantic
Microlab, Inc. (PCP)Ru(CO)Cl, (PCP)Ru(CO)OTf, (PCP)Ru(CO)-
(NHPh), (PCP)Ru(CO)(PMe3)(NHPh) (1), (PCP)Ru(CO)(N(Ph)C-
(Me)NH) (2), (PCP)Ru(CO)(N(Ph)C(C6F5)NH) (6), (PCP)Ru(CO)-
(H), and N,N′-dihexylcarbodiimide were synthesized as previously
reported.39,40,75,77 Benzonitrile, p-tolunitrile, 4-fluorobenzonitrile,
tert-butyl isocyanide, hexafluorobenzene, pentafluorobenzonitrile,
pentafluoronitrobenzene, pentafluoroanisole, benzanilide, N-meth-
ylacetamide, and cesium hydroxide monohydrate were purchased
from commercial sources and used without further purification.
Phenylisocyanate and benzaldehyde were vacuum distilled prior
to use.
of the green solid that was dried under vacuum (52% isolated yield).
IR (THF solution): νCO ) 1898 cm-1, νNH ) 3348 cm-1. 1H NMR
(C6D6, δ): 7.24 (2H, d, JHH ) 8 Hz, phenyl), 7.13 (4H, m, phenyl),
7.02 (3H, m, phenyl), 6.82 (2H, d, JHH ) 7 Hz, phenyl), 6.74 (1H,
d, JHH ) 7 Hz, phenyl), 4.73 (1H, br s, NH), 3.21 (4H, m, PCP
CH2), 1.95 (3H, s, p-CH3), 1.19 (18H, vt, N ) 12 Hz, PCP CH3),
1.10 (18H, vt, N ) 12 Hz, PCP CH3). 31P{1H} NMR (C6D6, δ):
78.6. 13C{1H} NMR (C6D6, δ): 212.1 (CO, t, JPC ) 13 Hz), 169.3,
167.4, 150.8, 147.9, 138.6, 134.7, 129.0, 128.4, 127.7, 123.7, 123.1,
121.4, 119.7 (phenyl and NCN), 37.1-37.7 (PCP CH2 and CMe3,
overlapping multiplets), 31.4, 31.0 (each a vt, N ) 4 Hz, PCP CH3),
21.5 (phenyl CH3). Anal. Calcd for C39H56N2OP2Ru: C, 64.00; H,
7.71; N, 3.81. Found: C, 64.15; H, 7.43; N, 3.61.
(PCP)Ru(CO)(F)(N(H)C(C6F5)NHPh) (7). A round-bottom
flask was charged with benzene (∼10 mL), (PCP)Ru(CO)(N(H)C-
(C6F5)NPh) (0.200 g, 0.25 mmol), C6F5CN (0.480 g, 2.5 mmol),
and H2O (45 µL, 2.5 mmol). The resulting solution was stirred for
12 h. The volatiles were evaporated under reduced pressure, the
residue washed with 2 × 10 mL of pentane and then collected by
vacuum filtration. The brown microcrystalline solid was dried in
(PCP)Ru(CO)(N(Ph)C(Ph)NH) (3). A 100 mL round-bottom
flask was charged with (PCP)Ru(CO)Cl (0.460 g, 0.82 mmol), 40
mL of benzene, and excess PMe3 (0.2 mL, 1.9 mmol). To this
solution was added 1.5 equiv of LiNHPh (0.130 g, 1.3 mmol). After
stirring for 30 min, excess benzonitrile (1.0 mL, 9.8 mmol) was
added, and the reaction mixture was stirred for 24 h. The volatiles
were evaporated under reduced pressure, and the residue was
washed with acetonitrile to give a yellow-green powder that was
collected by vacuum filtration and dried in vacuo (0.280 g, 48%).
IR (THF solution): νCO ) 1898 cm-1, νNH ) 3342 cm-1. 1H NMR
(CDCl3, δ): 7.24 (5H, m, phenyl), 7.03 (2H, t, JHH ) 12 Hz,
phenyl), 6.90 (2H, d, JHH ) 7 Hz, phenyl), 6.70 (4H, m, phenyl),
4.88 (1H, br s, NH), 3.36 (4H, m, PCP CH2), 1.23 (18H, vt, N )
12 Hz, PCP CH3), 1.19 (18H, vt, N ) 12 Hz, PCP CH3). 31P{1H}
NMR (CDCl3, δ): 77.9. 13C{1H} NMR (C6D6, δ): 212.1 (CO, t,
JPC ) 13 Hz), 169.2, 167.2, 150.6, 147.9, 137.4, 131.9, 131.8, 128.8,
128.4, 128.3, 127.7, 123.7, 123.2, 121.4 (phenyl and NCN), 37.2-
37.8 (overlapping multiplets, PCP CH2 and CMe3), 31.4, 31.1 (vt,
N ) 4 Hz, PCP CH3). Anal. Calcd for C38H54N2OP2Ru: C, 63.49;
H, 7.58; N, 3.90. Found: C, 63.65; H, 7.72; N, 3.82.
vacuo (0.165 g, 80%). IR (CH2Cl2 solution): νCO ) 1896 cm-1
,
νNH ) 3364 cm-1. 1H NMR (CD2Cl2, δ): 12.7 (1H, FLHN(Ph), d,
JHF ) 62 Hz), 7.14 (2H, phenyl, d, JHH ) 7 Hz), 7.01 (1H, phenyl,
t, JHH ) 7 Hz), 6.94 (2H, phenyl, d, JHH ) 7 Hz), 6.81 (1H, br s,
Ru-NH), 6.78 (1H, t, JHH ) 7 Hz, phenyl), 6.70 (2H, d, JHH ) 7
Hz, phenyl), 3.50 (2H, m, PCP CH2), 3.27 (2H, m, PCP CH2), 1.32
(18H, vt, N ) 12 Hz, PCP CH3), 1.23 (18H, vt, N ) 12 Hz, PCP
CH3). 31P{1H} NMR (CD2Cl2, δ): 80.5 (d, JPF ) 17 Hz). 13C{1H}
NMR (CD2Cl2, δ): 169.2, 156.1, 149.0, 139.1, 129.3, 124.8, 123.1,
122.4, 121.5 (phenyl and NCN), 36.1 (overlapping m’s, PCP CH2
and CMe3), 30.9, 30.7 (each a vt, N ) 4 Hz, PCP CH3), CO
and C6F5 ring carbons were not observed due to C-F coupling.
19F NMR (CD2Cl2, δ): -11.3 (dt, JHF ) 62 Hz, JPF ) 17 Hz),
-139.3, -151.7, -160.9 (each multiplet, C6F5 ring). Repeated
attempts to obtain elemental analysis failed to produce satisfactory
results. NMR spectra of complex 6 are provided in the Supporting
Information.
(PCP)Ru(CO)(N(Ph)C(p-FC6H4)NH) (4). The reaction pro-
cedure is analogous to that reported for complex 3; however,
p-FC6F4CN was used in place of benzonitrile and the final isolation
was performed by dissolving the residue in 2 mL of benzene and
adding 10 mL of acetonitrile to precipitate the product. Vacuum
filtration through a fine porosity frit allowed collection of the green
solid that was dried under vacuum (49% isolated yield). IR (THF
(PCP)Ru(CO)[PhNC{NH(hx)}N(hx)] (8). (PCP)Ru(CO)OTf
(0.2100 g, 0.31 mmol) was dissolved in 10 mL of THF, and
approximately 2 equiv of LiNHPh (0.060 g, 0.61 mmol) was added.
After stirring for approximately 30 min, the volatiles were
evaporated under reduced pressure. The residue was extracted with
10 mL of benzene and filtered through a fine porosity frit. The
dark green filtrate was combined with excess PMe3 (0.1 mL, 1
mmol), and the color changed to yellow. Two equivalents of N,N-
dihexylcarbodiimide (0.1300 mg, 0.62 mmol) was added to the
solution, and the reaction mixture was stirred for 2 h. The solution
was concentrated to approximately 3 mL, and 10 mL of CH3CN
was added to precipitate the product. Filtration through a fine
porosity frit and drying in vacuo provided a green powder (0.105
g, 41%). Crystals suitable for an X-ray diffraction study were
obtained by cooling a toluene/acetonitrile (1:5) solution to -20 °C
for a several days. IR (THF solution): νCO ) 1894 cm-1. 1H NMR
1
solution): νCO ) 1898 cm-1, νNH ) 3344 cm-1. H NMR (C6D6,
δ): 7.00-7.12 (9H, overlapping m’s, phenyl), 6.74 (1H, t, JHH
)
7 Hz, phenyl), 6.60 (2H, t, JHH ) 8 Hz, phenyl), 4.59 (1H, br s,
NH), 3.20 (4H, m, PCP CH2), 1.17 (18H, vt, N ) 12 Hz, PCP
CH3), 1.06 (18H, vt, N ) 12 Hz, PCP CH3). 31P{1H} NMR (C6D6,
δ): 78.6. 19F{1H} NMR (C6D6, δ): -111.8. 13C{1H} NMR (C6D6,
δ): 212.0 (t, JPC ) 13 Hz, CO), 169.0, 165.8, 164.6, 161.3, 150.4,
147.8, 133.4, 129.7, 129.6, 128.5, 128.4, 123.7, 123.2, 121.4, 120.0,
115.4, 115.1 (phenyl and NCN), 37.1-37.7 (PCP CH2 and CMe3,
overlapping multiplets), 31.3, 31.0 (each a vt, N ) 4 Hz, PCP CH3).
Anal. Calcd for C38H53FN2OP2Ru: C, 62.02; H, 7.26; N, 3.81.
Found: C, 62.52; H, 7.13; N, 3.82.
(C6D6, δ): 7.40 (2H, d, JHH ) 8 Hz, phenyl), 7.30 (2H, t, JHH
)
(PCP)Ru(CO)(N(Ph)C(p-MeC6H4)NH) (5). The reaction pro-
cedure is analogous to that reported for complex 3; however,
p-MeC6H4CN was used in place of benzonitrile and the final
isolation was performed by dissolving the residue in 2 mL of
benzene and adding 10 mL of acetonitrile to precipitate the product.
Vacuum filtration through a fine porosity frit allowed collection
8 Hz, phenyl), 7.02 (3H, s, PCP phenyl), 6.80 (1H, t, JHH ) 8 Hz,
phenyl), 3.30 (2H, m, PCP CH2), 3.16 (2H, m, PCP CH2), 3.00
(4H, m, NCH2), 1.60 (2H, m, CH2), 1.0-1.3 (50H, overlapping
m’s, PCP CH3 and hexyl), 0.80 (6H, overlapping m’s, CH3).
31P{1H} NMR (C6D6, δ): 75.3. 13C{1H} NMR (C6D6, δ): 212.5
(t, JPC ) 16 Hz, CO), 170.5, 159.1, 153.2, 148.2, 129.4, 128.2,
123.8, 122.8, 121.7, 121.1, 117.0 (phenyl and NCN), 48.1, 44.3,
42.3, 37.6, 37.3, 36.7, 32.2, 32.0, 31.7, 30.9, 30.5, 30.1, 28.6, 27.0,
(77) Gusev, D. G.; Madott, M.; Dolgushin, F. M.; Lyssenko, K. A.; Antipin,
M. Y. Organometallics 2000, 19, 1734-1739.
2904 Inorganic Chemistry, Vol. 44, No. 8, 2005

Reactions of (PCP)Ru(CO)(NHPh)(PMe3)
23.0, 14.4 (PCP CH3 and hexyl). Anal. Calcd for C44H75N3OP2Ru:
C, 64.05; H, 9.16; N, 5.09. Found: C, 64.00; H, 9.15; N, 5.01.
(PCP)Ru(CO){N(Ph)C(NHPh)O} (9). (PCP)Ru(CO)OTf (0.430
g, 0.64 mmol) was dissolved in 20 mL of THF, and 2 equiv of
LiNHPh (0.120 g, 1.2 mmol) was added. After stirring for
approximately 30 min, the volatiles were evaporated under reduced
pressure. The residue was extracted with 10 mL of benzene and
filtered through a fine porosity frit. The dark green benzene filtrate
was combined with excess PMe3 (0.2 mL, 2 mmol), and the color
changed to yellow. Excess phenyl isocyanate (0.10 mL, 0.92 mmol)
was added to the reaction solution followed by stirring for 1 h.
The reaction solution was reduced to dryness under reduced
pressure, and the residual material was washed with MeOH.
Vacuum filtration through a fine porosity frit followed by drying
in vacuo yielded a green powder (0.200 g, 44%). Crystals suitable
for an X-ray diffraction study were obtained by cooling a toluene/
pentane (1:5) solution of 9 to -20 °C for 1 day. IR (THF
37.8 (overlapping multiplets, PCP CH3), 30.9, 30.8 (vt, N ) 4 Hz,
PCP CH3), 19.2 (s, CH3). Anal. Calcd for C28H49NO2P2Ru: C,
56.55; H, 8.30; N, 2.36. Found: C, 56.53; H, 8.06; N, 2.34.
(PCP)Ru(CO)(PMe3)(H) (12). (PCP)Ru(CO)H (0.100 g, 0.19
mmol) was dissolved in 10 mL of benzene. Excess PMe3 (0.1 mL,
1.1 mmol) was added via syringe with an immediate color change
from red to yellow. After stirring for 10 min, the volatiles were
removed under reduced pressure to give a yellow powder
1
(0.110 g, 96%). IR (THF solution): νCO ) 1900 cm-1. H NMR
(C6D6, δ): 7.00 (3H, m, phenyl), 3.16 (4H, overlapping m’s, PCP
CH2), 1.28 (18H, vt, N ) 12 Hz, PCP CH3), 1.22 (18H, vt, N ) 12
Hz, PCP CH3), 0.92 (9H, d, JPH ) 5 Hz, P(CH3)3), -9.60 (1H, m,
Ru-H). 31P{1H} NMR (C6D6, δ): 104.5 (br s, PCP), -22.3 (br s,
PMe3). 13C{1H} NMR (C6D6, δ): 207.5 (m, CO), 150.4, 138.5,
122.9, 120.5 (phenyl), 40.4, 38.4, 35.2 (PCP CH2 and CMe3), 31.4,
1
29.7 (vt, N ) 4 Hz, PCP CH3), 21.1 (d, JPC ) 16 Hz, PMe3).
Anal. Calcd For C28H53OP3Ru: C, 56.08; H, 8.91. Found: C, 55.67;
H, 8.89.
1
solution): νCO ) 1902 cm-1. H NMR (C6D6, δ): 7.36 (2H, d,
(PCP)Ru(CO)(CNtBu)(NHPh) (13). (PCP)Ru(CO)OTf (0.2100
g, 0.31 mmol) was dissolved in 10 mL of THF, and 2 equiv of
LiNHPh (0.060 g, 0.61 mmol) was added. After stirring for 30 min,
the volatiles were evaporated under reduced pressure. The residue
was extracted with 10 mL of benzene and filtered through a fine
porosity frit. The dark green benzene filtrate was combined with
PMe3 (0.1 mL, 1 mmol) with an immediate color change to yellow.
Two equivalents of tert-butyl isonitrile (0.07 mL, 0.6 mmol) was
added, and the reaction mixture was stirred for 30 min. The solution
was concentrated to 1 mL under reduced pressure, and 10 mL of
CH3CN was added to precipitate the product. Filtration through a
fine porosity frit and drying in vacuo provided a green powder
JHH ) 7 Hz, phenyl), 7.27 (2H, t, JHH ) 7 Hz, phenyl), 7.15 (2H,
d, JHH ) 7 Hz, phenyl), 7.04 (5H, overlapping m’s, phenyl), 6.87
(1H, t, JHH ) 7 Hz, phenyl), 6.76 (1H, t, JHH ) 7 Hz, phenyl),
3.25 (4H, m, PCP CH2), 1.18 (18H, vt, N ) 12 Hz, PCP CH3),
1.11 (18H, vt, N ) 12 Hz, PCP CH3). 31P{1H} NMR (C6D6, δ):
75.6. 13C{1H} NMR (C6D6, δ): 211.3 (t, JPC ) 13 Hz, CO), 167.6,
155.4, 149.0, 148.1, 139.4, 129.8, 128.8, 123.5, 123.3, 121.8, 121.1,
117.9 (phenyl and NCN), 37.3, 36.8 (each a t, JPC ) 5 Hz, PCP
CMe3), 36.5 (t, JPC ) 10 Hz, PCP CH2), 30.8, 30.7 (each a t, JPC
) 2 Hz, PCP CH2). Anal. Calcd for C38H54N2O2P2Ru: C, 62.19;
H, 7.42; N, 3.82. Found: C, 62.13; H, 7.08; N, 3.74.
(PCP)Ru(CO){OC(Ph)N(Ph)} (10). (PCP)Ru(CO)OTf (0.190
g, 0.28 mmol) was dissolved in 10 mL of THF, and 2 equiv of
LiNHPh (0.050 g, 0.51 mmol) was added. The mixture was stirred
for 30 min, and then the volatiles were removed under reduced
pressure. The residue was extracted with 10 mL of benzene and
filtered through a fine porosity frit. The dark green benzene filtrate
was combined with PMe3 (0.1 mL, 1 mmol) with a color change
to yellow observed. One equivalent of benzanilide (0.055 g, 0.28
mmol) was added, and the reaction mixture was stirred for 2 h.
The solution was concentrated to 3 mL under reduced pressure,
and 10 mL of CH3CN was added to precipitate the product.
Filtration through a fine porosity frit and drying in vacuo yielded
a green powder (0.110 g, 55%). Crystals suitable for an X-ray
diffraction study were obtained by slow evaporation of a pentane
(0.090 g, 42%). IR (THF solution): νCO ) 1923 cm-1, νNH ) 3346
1
cm-1, νCN ) 2124 cm-1. H NMR (C6D6, δ): 7.20 (1H, t, JHH
)
7 Hz, phenyl), 7.13 (3H, overlapping m’s, phenyl), 7.02 (1H, t,
JHH ) 7 Hz, phenyl), 6.68 (1H, d, JHH ) 7 Hz, phenyl), 6.39 (1H,
t, JHH ) 7 Hz, phenyl), 6.14 (1H, d, JHH ) 7 Hz, phenyl), 3.47
(2H, m, PCP CH2), 3.23 (2H, m, PCP CH2), 1.21 (18H, vt, N ) 12
Hz, PCP CH3), 1.17 (9H, s, CNtBu CH3), 1.10 (18H, vt, N ) 12
Hz, PCP CH3). 31P{1H} NMR (C6D6, δ): 83.2. 13C{1H} NMR
(C6D6, δ): 206.7 (CO, t, 2JPC ) 12 Hz), 175.0, 163.1, 156.0, 148.6,
124.2, 122.3, 118.8, 114.5, 108.0 (phenyl and CNtBu), 56.2 (s,
NCMe3), 38.0 (PCP CH2, t, JPC ) 10 Hz), 37.1, 36.7 (PCP CMe3,
each t, JPC ) 6 Hz), 31.6, 31.1 (PCP CH3, each vt, N ) 4 Hz),
30.4 (isonitrile CH3). Anal. Calcd For C36H58N2OP2Ru: C, 61.96;
H, 8.38; N, 4.01. Found: C, 62.02; H, 8.39; N, 3.96.
1
solution of 10. IR (THF solution): νCO ) 1902 cm-1. H NMR
(C6D6, δ): 7.67 (2H, m, phenyl), 7.28 (2H, d, JHH ) 8 Hz, phenyl),
7.10 (2H, t, JHH ) 6 Hz, phenyl), 7.06 (3H, s, PCP phenyl), 6.98
(3H, m, phenyl), 6.82 (1H, t, JHH ) 6 Hz, phenyl), 3.34 (2H, m,
PCP CH2), 3.22 (2H, m, PCP CH2), 1.15 (36H, overlapping m’s,
PCP CH3). 31P{1H} NMR (C6D6, δ): 75.9. 13C{1H} NMR (C6D6,
δ): 211.4 (t, JPC ) 12 Hz, CO), 170.7, 167.9, 149.0, 148.6, 135.7,
126.6, 129.4, 128.6, 124.5, 123.5, 122.2, 121.7 (phenyl and
NCN), 37.6, 36.9 (t, JPC ) 6 Hz, PCP CMe3), 36.7 (t, JPC ) 10
Hz, PCP CH2), 31.0, 30.8 (vt, N ) 4 Hz, PCP CH3). Anal. Calcd
for C38H53NO2P2Ru: C, 63.49; H, 7.43; N, 1.95. Found: C, 63.49;
H, 7.47; N, 2.02.
(PCP)Ru(CO)(OH) (14). To a solution of (PCP)Ru(CO)Cl
(0.200 g, 0.36 mmol) in 15 mL of THF was added an excess of
CsOH‚H2O. The mixture was stirred overnight (∼12 h), and the
CO absorption (IR spectroscopy) was observed to change from 1919
to 1896 cm-1. The solution was filtered through a fine porosity
frit, and the volatiles were removed from the filtrate under reduced
pressure to give a brown powder (0.180 g, 92%). NMR and IR
spectroscopy revealed a clean product, and no further purification
steps were taken. IR (THF solution): νCO ) 1896 cm-1. 1H NMR
(C6D6, δ): 6.98 (3H, m, phenyl), 3.85 (1H, br s, OH), 3.03 (4H,
overlapping m’s, PCP CH2), 1.22 (36H, overlapping m’s, PCP CH3).
31P{1H} NMR (C6D6, δ): 67.3. 13C{1H} NMR (C6D6, δ): 212.2
(CO, t, 2JPC ) 12 Hz), 162.9 (t, JPC ) 2 Hz, phenyl), 149.4 (t, JPC
) 7 Hz, phenyl), 128.0 (s, phenyl), 122.4 (t, JPC ) 7 Hz, phenyl),
36.8, 35.7 (each a vt, N ) 14 Hz, PCP CMe3), 34.2 (vt, N ) 20
Hz, PCP CH2), 30.0 (overlapping m’s, PCP CH3). Anal. Calcd For
C25H44O2P2Ru: C, 55.64; H, 8.22. Found: C, 55.40; H, 8.10.
(PCP)Ru(CO)(PMe3)(OH) (15). To a solution of (PCP)Ru(CO)-
(OH) (0.100 g, 0.2 mmol) in 10 mL of benzene was added excess
(PCP)Ru(CO){OC(Me)N(Me)} (11). The procedure used is
analogous to that for complex 10 with 11 isolated in 50% yield.
1
IR (THF solution): νCO ) 1902 cm-1. H NMR (C6D6, δ): 7.06
(3H, m, phenyl), 3.30 (2H, m, PCP CH2), 3.15 (2H, m, PCP CH2),
2.96 (3H, s, CH3), 1.49 (3H, s, CH3), 1.24 (18H, vt, N ) 12 Hz,
PCP CH3), 1.18 (18H, vt, N ) 12 Hz, PCP CH3). 31P{1H} NMR
(C6D6, δ): 75.0. 13C{1H} NMR (C6D6, δ): 210.7 (t, JPC ) 12 Hz,
CO), 173.6, 169.4, 149.5, 122.9, 121.3 (phenyl and NCN), 36.2-
Inorganic Chemistry, Vol. 44, No. 8, 2005 2905

Zhang et al.
PMe3 (0.1 mL). Upon addition of PMe3, the color of the solution
changed from brown to yellow. After stirring at room temperature
for 5 min, the volatiles were evaporated under reduced pressure to
give a yellow powder. After drying in vacuo, 0.110 g of the yellow
and -157.1 (d, JFF ) 13 Hz); o-MeOC6F4CN (<10% product):
-133.9 (ddd, JFF ) 21, 7, 4 Hz), -147.0 (td, JFF ) 21, 4 Hz),
-156.8 (ddd, JFF ) 21, 7, 4 Hz), and -162.9 (t, JFF ) 21 Hz).
Some fluorine resonances exhibit evidence of coupling that is not
resolved.
powder was isolated (97%). IR (THF solution): νCO ) 1892 cm-1
.
1H NMR (C6D6, δ): 7.11 (3H, m, phenyl), 3.50 (2H, m, PCP CH2),
Reaction of (PCP)Ru(CO)(N(H)C(C6F5)NPh) (6), C6F5CN,
and H2O. An NMR tube was charged with complex 6 (0.0200 g,
0.025 mmol) and C6D6 (0.5 mL). Ten equivalents each of C6F5CN
(0.050 g, 0.25 mmol) and H2O (5 µL, 0.25 mmol) were added, and
the solution was monitored by NMR spectroscopy. After 12 h, all
of the (PCP)Ru(CO)(N(H)C(C6F5)NPh) was quantitatively trans-
formed to (PCP)Ru(CO)(F)(N(H)C(C6F5)NHPh) (7) according to
1H, 31P, and 19F NMR spectroscopy. 19F NMR spectroscopy also
revealed multiple new resonances accompanied by excess
C6F5CN and complex 7. These new organic species were not
assigned due to the formation of multiple species in low yields.
Reaction of (PCP)Ru(CO)(N(H)C(C6F5)NPh) (6), C6F5CN,
and MeOH. An NMR tube was charged with complex 6 (0.0200
g, 0.025 mmol) and C6D6 (0.5 mL). Ten equivalents each of
C6F5CN (0.050 g, 0.25 mmol) and MeOH (8 µL, 0.25 mmol) were
added, and the solution was monitored by NMR spectroscopy. After
6 h, all of the complex (PCP)Ru(CO)(N(H)C(C6F5)NPh) was
quantitatively transformed to (PCP)Ru(CO)(F)(N(H)C(C6F5)-
2
3.23 (2H, m, PCP CH2), 1.45 (9H, d, JPH ) 6 Hz, PMe3), 1.24
(18H, vt, N ) 12 Hz, PCP CH3), 1.17 (18H, vt, N ) 12 Hz, PCP
CH3), -4.42 (1H, d, JPH ) 8 Hz, OH). 31P{1H} NMR (C6D6, δ):
2
2
74.9 (d, JPP ) 20 Hz, PCP phosphine), -23.2 (t, JPP ) 20 Hz,
PMe3). 13C{1H} NMR (C6D6, δ): 206.2 (CO, m), 148.5 (t, JPC
)
7 Hz, phenyl), 128.9 (s, phenyl), 124.3 (s, phenyl), 122.0 (m,
phenyl), 39.8 (m, PCP CH2), 38.7, 37.3 (each a vt, N ) 4 Hz, PCP
1
CMe3), 31.7, 31.3 (each a vt, N ) 4 Hz, PCP CH3), 23.0 (d, JPC
) 18 Hz, P(CH3)3). Anal. Calcd For C28H53O2P3Ru: C, 54.62; H,
8.68. Found: C, 54.71; H, 8.48.
(PCP)Ru(CO)(CNtBu)(OH) (16). Excess CNtBu (0.1 mL) was
added to a solution of (PCP)Ru(CO)(OH) (14) (0.100 g, 0.19 mmol)
in 10 mL of benzene. The addition of the isonitrile resulted in an
immediate color change from brown to yellow. After stirring for 5
min, the volatiles were removed under reduced pressure to give a
pale yellow powder. After drying in vacuo, 0.105 g of yellow
powder was isolated (95%). IR (THF solution): νCN ) 2123 cm-1
,
νCO ) 1906 cm-1. 1H NMR (C6D6, δ): 7.16 (3H, m, phenyl), 3.64
(2H, m, PCP CH2), 3.24 (2H, m, PCP CH2), 1.37 (18H, vt, N ) 12
Hz, PCP CH3), 1.28 (18H, vt, N ) 12 Hz, PCP CH3), 1.04 (9H, s,
isonitrile CH3), -4.53 (br s, OH). 31P{1H} NMR (C6D6, δ): 86.8.
13C{1H} NMR (C6D6, δ): 206.0 (CO, t, 2JPC ) 12 Hz), 176.8, 149.0,
128.4, 123.7, 121.6 (PCP phenyl and CN), 55.6 (CNCMe3),
37.7 and 36.5 (overlapping, PCP CH2 and CMe3), 31.1 and 30.9
(each a vt, N ) 4 Hz, PCP CH3), 30.6 (CNCMe3). Anal. Calcd for
C30H53NO2P2Ru: C, 57.86; H, 8.58; N, 2.25. Found: C, 57.79; H,
8.43; N, 2.29.
1
NHPh) (7) as determined by H, 31P, and 19F NMR spectroscopy.
19F NMR spectroscopy also revealed the new organic species
o-MeOC6F4CN and p-MeOC6F4CN (∼10:1 ratio). The identity of
the organic products was confirmed by comparison with indepen-
dently made compounds (see above). In addition, another organic
species {-142.2 (d, JFF ) 8 Hz), -153.2 (t, JFF ) 22 Hz), -162.0
(m) by 19F NMR spectroscopy} was formed by reaction of
MeOH with C6F5CN catalyzed by the base.63 The product mix-
ture was also analyzed using GC-MS. The organic products
o-MeOC6F4CN and p-MeOC6F4CN were identified as resolved GC
traces with identical parent ions in the corresponding mass spectra
(Mw ) 205). In addition, a GC trace corresponding to the starting
material C6F5CN was identified with Mw ) 193. The third organic
product was identified by GC-MS with Mw ) 225 and is likely
the result of addition of MeOH to the CN triple bond of C6F5CN
to produce C6F5C(dNH)OMe (as previously reported).63
Reaction of (PCP)Ru(CO)(NHPh)(PMe3) (1) with Benzalde-
hyde. A screw-cap NMR tube was charged with 20 mg of (PCP)-
Ru(CO)(NHPh)(PMe3) (1) in 0.6 mL of C6D6. Approximately 2
equiv of benzaldehyde (∼5 µL) was added via microsyringe. After
12 h at room temperature, the color of the reaction solution changed
from green to yellow. The 1H NMR spectrum revealed a complex
mixture of products. 31P NMR spectroscopy showed two major
products consistent with formation of the amidate complex (PCP)-
Ru(CO){OC(Ph)N(Ph)} (10) (75.6 ppm) (∼40%) and the free
organic substrate PCPH (34.0 ppm) (∼30%). The assignments of
these resonances were confirmed upon addition of authentic
Reaction of (PCP)Ru(CO)(N(H)C(C6F5)NPh) (6), C6F5NO2,
and MeOH. An NMR tube was charged with complex 6 (0.0200
g, 0.025 mmol) and C6D6 (0.5 mL). Ten equivalents each of
C6F5NO2 (0.055 g, 0.25 mmol) and MeOH (8 µL, 0.25 mmol) were
added, and the solution was monitored by NMR spectroscopy. After
5 h, all of the complex (PCP)Ru(CO)(N(H)C(C6F5)NPh) was
quantitatively transformed to (PCP)Ru(CO)(F)(N(H)C(C6F5)NHPh)
(7) as determined by 1H, 31P, and 19F NMR spectroscopy. 19F NMR
spectroscopy also revealed two new organic species. The major
samples. The existence of free PCPH was also consistent with 31
P
1
NMR spectroscopy as well as a resonance at 2.9 ppm in the H
NMR spectrum. From the reaction mixture, complex 10 was isolated
in approximately 20-30% yield depending on the scale of the
reaction. The ruthenium hydride complexes (PCP)Ru(CO)(PMe3)H
(12) (∼10%) and (PCP)Ru(CO)H (∼5%) were also observed by
1H and 31P NMR spectroscopy and confirmed upon addition of
authentic samples. Other uncharacterized compounds were observed
by 31P NMR spectroscopy with total yield of <15% as estimated
by 31P NMR resonances.
organic product {-148.6 (d, JFF ) 20 Hz) and -157.4 (d, JFF
)
20 Hz)} was assigned as p-MeOC6F4NO2 (>90%), and the
minor product {-143.2 (ddd, JFF ) 23, 7, 3 Hz), -149.8 (d,
JFF ) 23 Hz) -155.2 (m), and -161.6 (t, JFF ) 23 Hz)} was
assigned as o-MeOC6F4NO2 (<10%). The product mixture was also
analyzed by GC-MS. The organic products p-MeOC6F4NO2 and
o-MeOC6F4NO2 were identified as resolved peaks in the GC with
identical parent ion peaks (Mw ) 225). The starting material
C6F5NO2 (Mw ) 213) was also observed by GC-MS.
Reaction of (PCP)Ru(CO)(F)(N(H)C(C6F5)NHPh) (7) with
KOtBu. An NMR tube was charged with (PCP)Ru(CO)(F)(N(H)C-
(C6F5)NHPh) (7) (0.0200 g, 0.24 mmol) and C6D6 (0.5 mL). Excess
KOtBu powder (∼0.0200 g) was added to the benzene solution,
and the heterogeneous reaction was monitored by NMR spectros-
copy. The concentration of complex 7 decreased and was ac-
p- and o-MeOC6F4CN. The previously reported procedure was
used to prepare p- and o-MeOC6F4CN.78 The product mixture was
analyzed by 19F NMR in C6D6. Three compounds were ob-
served using 19F NMR spectroscopy (δ): starting material
C6F5CN: -133.2 (m), -144.6 (tt, JFF ) 21.7, 5.6 Hz), and -159.5
(m); p-MeOC6F5CN (>90% product): -135.5 (d, JFF ) 13 Hz)
(78) Birchall, J. M.; Haszeldine, R. N.; Jones, M. E. J. Chem. Soc. (C)
1971, 1343-1347.
2906 Inorganic Chemistry, Vol. 44, No. 8, 2005

Reactions of (PCP)Ru(CO)(NHPh)(PMe3)
companied by the formation of the Ru(II) amidinate complex
and immediately monitored by NMR spectroscopy. By monitoring
the appearance of free PMe3 and disappearance of the resonance
due to the coordinated PMe3, the half-life for phosphine ligand
exchange was determined to be approximately 7 min. There was
no change in the appearance of other resonances in the H NMR
spectra.
1
(PCP)Ru(CO)(NHC(C6F5)NPh) (6) as determined by H, 31P, and
19F NMR spectroscopy. After approximately 20 min, complex 7
was quantitatively transformed to (PCP)Ru(CO)(NHC(C6F5)NPh)
(6). After several hours of reaction, the color changed from yellow
to dark brown, and NMR spectroscopy revealed decomposition of
(PCP)Ru(CO)(NHC(C6F5)NPh) into multiple products.
1
Reaction of C6F5CN with KOtBu. To a solution of C6F5CN
(0.100 g, 0.52 mmol) in 5 mL of THF was added a solution of
KOtBu (0.050 g, 0.45 mmol) in 5 mL of THF. Upon combination
of the two solutions, an immediate change from colorless to yellow
was observed. After stirring for 1 h, the volatiles were evaporated,
and the resulting residue was extracted with 5 mL of benzene. The
benzene filtrate was dried to a yellow oil under reduced pressure,
and a 19F NMR spectrum of the oil was acquired. While a small
amount of starting material (C6F5CN) was observed, the major
product (>70%) exhibited resonances at -135.5 and -149.8 ppm
(each a doublet) and was assigned as p-tBuO-C6F4CN. Resonances
attributed to the ortho-substituted compound were also observed
(∼20%) at -133.7, -147.4, -150.8, and -160.0 ppm. Other minor
products were observed in low yields and were not assigned.
Rate of Phosphine Exchange between (PCP)Ru(CO)(PMe3)-
(NHPh) (1) and PMe3-d9. In a screw-cap NMR tube, approxi-
mately 0.020 g of complex 1 was dissolved in 0.6 mL of C6D6.
The NMR tube was charged with an excess of PMe3-d9 (∼15 equiv)
Acknowledgment. The National Science Foundation
(CAREER Award; CHE 0238167) and the Alfred P. Sloan
Foundation (Research Fellowship) are acknowledged for
financial support of this research. Mass spectra were obtained
at the Mass Spectrometry Facility for Biotechnology (NCSU).
Partial funding for the facility was obtained from the North
Carolina Biotechnology Center and the National Science
Foundation. We acknowledge useful discussions with Profes-
sor SonBinh Nguyen.
Supporting Information Available: Details of X-ray data
acquisition, crystal data, collection and refinement data, atomic
coordinates, bond distances and angles, and anisotropic displace-
ment coefficients for complexes 7-10, NMR spectra of complex
7, and details of kinetic studies. This material is available free of
charge via the Internet at http://pubs.acs.org.
IC0483592
Inorganic Chemistry, Vol. 44, No. 8, 2005 2907