Exploring the reactivity of a coordinatively unsaturated Cp*Ru(κ2-P,O) complex with small molecule substrates: Application in E-H bond activation (E = H, B, and Si)

Article abstract of DOI:10.1039/b903420j

Treatment of [Cp*RuCl]₄ with 1-diisopropylphosphino-2- indanone (1) afforded Cp*Ru(Cl)(κ²-P,O-1) (2) in 96% isolated yield. Dehydrohalogenation of 2 under an atmosphere of N₂ provided the dinuclear complex 4 (78% isolated

Full text of DOI:10.1039/b903420j

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PAPER
www.rsc.org/dalton | Dalton Transactions
2
Exploring the reactivity of a coordinatively unsaturated Cp*Ru(j -P,O)
complex with small molecule substrates: application in E–H bond activation
(
E = H, B, and Si)†
a
a
b
c
a
Matthew A. Rankin,‡ Kevin D. Hesp, Gabriele Schatte, Robert McDonald and Mark Stradiotto*
Received 18th February 2009, Accepted 25th March 2009
First published as an Advance Article on the web 16th April 2009
DOI: 10.1039/b903420j
2
Treatment of [Cp*RuCl]
4
with 1-diisopropylphosphino-2-indanone (1) afforded Cp*Ru(Cl)(k -P,O-1)
(
2) in 96% isolated yield. Dehydrohalogenation of 2 under an atmosphere of N
2
provided the dinuclear
2
complex 4 (78% isolated yield), which is comprised of two coordinatively unsaturated Cp*Ru(k -P,O)
fragments (3) linked by an end-on coordinated m-N
directly, reactivity studies demonstrated that 4 can serve as a convenient source of 3. Isolable adducts of
were prepared via exposure of 4 to an atmosphere of CO (93% yield, 5a) or two equivalents of PhCN
91% yield, 5b). Exposure of 4 to an atmosphere of H ) (6) quantitatively;
afforded the adduct 3·(r-H
the clean conversion of 6 back into 4 occurred upon evacuation and re-introduction of a N
atmosphere. Treatment of 4 with two equivalents of PhSiH or Ph SiH afforded products featuring
H) Ru–SiPhX–O fragments (7a and 7b, respectively; both 95% isolated yield) corresponding to net
2
ligand. Although complex 3 has not been observed
3
(
2
2
2
3
2
2
(
2
double geminal Si–H bond activation of the organosilane in which the extruded silylene fragment has
inserted into the Ru–O bond of the putative intermediate 3. Similar reactivity was observed upon
treatment of 4 with two equivalents of mesitylborane to give 8 (82% isolated yield). While minimal
Ru–H ◊ ◊ ◊ Si interactions were identified for 7a,b in solution and the solid state, the hydride ligands in 8
were observed to bridge ruthenium and boron. Crystallographic characterization data were obtained
for 2·0.5C
6
6
H , 4, 7b, and 8.
Introduction
accounts of cooperative substrate activation across a Ru–X moiety
5
(
e.g. X = NR
2
, OR, PR
2
), we identified coordinatively unsaturated
5
5
5
Coordinatively unsaturated (h -C
5
R
5
)RuL
n
(h -C
5
H
5
= Cp; h -
2
Cp*Ru(k -P,O) complexes supported by phosphinoenolate chelat-
C
5
Me
5
= Cp*) complexes serve as a rich source of novel stoi-
ing ligands as appealing targets of inquiry. Although heterobiden-
1
chiometric and catalytic reactivity. While considerable insights
have been gained through the study of both neutral Cp*RuL(X)
6
tate species of this type were unknown prior to this work, Caulton
4
and co-workers had demonstrated that p-donation from oxygen in
+
-
complexes and [Cp*RuL
activity of coordinatively unsaturated Cp*Ru(k -L,X) complexes
2
] X salts, investigations probing the re-
i
monodentate complexes such as Cp*Ru(P Pr
2
Ph)(OCH
2
CF ) can
3
2
serve to stabilize such unsaturated species, as well as to promote
metal-mediated substrate transformations. Herein we report on
supported by monoanionic, heterobidentate LX-type ligands are
2
rare. Nonetheless, such reactivity surveys are warranted, since
2
the reactivity of the coordinatively unsaturated Cp*Ru(k -P,O)
studies of alternative classes of Cp*RuL
n
complexes supported by
7
complex 3, which is apparently generated in situ from the
new ancillary ligands continue to advance our understanding of
how alterations to the ligand steric and/or electronic properties
can influence the reactivity behavior of coordinatively unsaturated
ruthenium species.
isolable dinitrogen complex 3
adducts with a range of two-electron donor ligands, complex 3
engages in E–H bond activation chemistry with Ph SiH , PhSiH
and MesBH
derived from the net insertion of silicon or boron into the Ru–O
bond of 3.
2
(l-N ) (4). In addition to forming
2
2
2
3
,
2
(Mes = 2,4,6-trimethylphenyl), affording products
3
In building on pioneering research by the groups of Tilley,
4
1c
Caulton, and Valerga, who have established the utility of
the Cp*RuPR (X) subset of complexes for facile E–H bond
3
activations (E = main group element), and in light of various
Results and discussion
a
Department of Chemistry, Dalhousie University, Halifax, NS B3H 4J3,
In seeking to prepare a synthetic precursor to a coordinatively
Canada. E-mail: mark.stradiotto@dal.ca; Fax: +1 902 494-1310; Tel: +1
2
unsaturated Cp*Ru(k -P,O) phosphinoenolate complex, ketone
9
02 494-7190
b
1 was treated with 0.25 [Cp*RuCl] (Scheme 1); after 45 min,
4
Saskatchewan Structural Sciences Centre, University of Saskatchewan,
Saskatoon, SK S7N 5C9, Canada
3
1
P NMR analysis of the reaction mixture revealed the clean
formation of a single phosphorus-containing product (100.5 ppm;
), which in turn was obtained in 96% isolated yield. Both
c
X-Ray Crystallography Laboratory, Department of Chemistry, University
of Alberta, Edmonton, Alberta, Canada T6G 2G2
2
†
CCDC reference numbers 654072–654074 and 719567. For crystallo-
graphic data in CIF or other electronic format see DOI: 10.1039/b903420j
Present address: Department of Chemistry, Massachusetts Institute of
Technology, Cambridge, Massachusetts, USA 02139.
NMR spectroscopic and X-ray crystallographic data confirmed
2
the identity of 2 as Cp*Ru(Cl)(k -P,O-1-diisopropylphosphino-
‡
8
2-indanone). An ORTEP diagram for 2·0.5C
6
6
H is provided in
4
756 | Dalton Trans., 2009, 4756–4765
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Fig. 1 ORTEP diagram for 2·0.5C
6
H
6
shown with 50% displacement
ellipsoids and with selected H atoms and the benzene solvate omitted for
clarity.
Scheme 1 Synthesis of 2 and the proposed interconversion of 3 and 4.
Fig. 1, while diffraction data and selected metrical parameters
for each of the crystallographically characterized compounds
reported herein are provided in Tables 1 and 2, respectively.† The
structural features of 2 compare well with those of the only other
of the resulting dark green solution revealed the quantitative
conversion to a product (4) that exhibited a single broad resonance
(50.1 ppm, Dn1/2 = 213 Hz, 300 K). Upon work-up, 4 was isolated
in 78% yield. Combustion analysis data provided preliminary
2
crystallographically characterized Cp*RuCl(k -P,O) complex to
9
feature a phosphinoketone ligand; notably, the relatively short
evidence for the presence of a coordinated N
2
ligand in 4. Such a
˚
O–C distance (1.228(3) A) supports the description of 2 as a
proposal also appeared to be consistent with the observation of a
3
1
1
phosphinoketone complex, unlike the phosphinoenolate species
featured herein (vide infra).
distinctly different P{ H} NMR resonance (44.9 ppm, Dn1/2 =
240 Hz, 300 K; possibly corresponding to 3 for degassed solutions
of 4, which in turn afforded the originally observed spectrum (vide
supra) upon re-introduction of dinitrogen. The more definitive
identification of 4 as a dinuclear phosphinoenolate species (i.e.
In an effort to effect the dehydrohalogenation of 2 as a route to
the target complex 3, a deep red solution of the former in benzene
3
1
1
was treated with NaN(SiMe
3
)
2
(Scheme 1); P{ H} NMR analysis
Table 1 Crystallographic data for 2, 4, 7b, and 8
2
4
7b
8
Empirical formula
Formula weight
Crystal dimensions
Crystal system
Space group
C
559.08
0.20 ¥ 0.18 ¥ 0.10
Monoclinic
28
H
39ClOPRu
C
995.16
0.08 ¥ 0.05 ¥ 0.05
Monoclinic
50
H
70
N
2
O
2
P
2
Ru
2
C
667.88
0.48 ¥ 0.45 ¥ 0.22
Orthorhombic
37
H
47OPRuSi
C
615.57
0.64 ¥ 0.28 ¥ 0.26
Monoclinic
34
H48BOPRu
P2
1
/c
P2
1
/c
P2
1
2
1
2
1
P2 /m
1
a/A˚
20.2188(2)
8.5282(3)
16.0143(3)
90
105.8122(10)
90
2656.77(11)
4
1.398
17.4049(11)
13.5276(8)
23.1490(19)
90
118.873(3)
90
4772.8(6)
4
1.385
0.739
0.9640–0.9432
43.94
-17 ≤ h ≤ 18
-14 ≤ k ≤ 14
-24 ≤ l ≤ 24
16933
13.0305(12)
14.5399(13)
17.6901(16)
90
90
90
3351.6(5)
4
1.324
0.579
0.8833–0.7687
55.02
9.6050(6)
12.3491(8)
13.2765(9)
90
96.8204(8)
90
1563.62(18)
2
1.307
0.577
0.8645–0.7091
54.96
-12 ≤ h ≤ 12
-16 ≤ k ≤ 16
-17 ≤ l ≤ 17
13179
b/A˚
c/A˚
◦
a/
◦
b/
◦
g /
V/A˚
3
Z
r
-3
calcd/g cm
m/mm
Range of transmission
-1
0.769
0.9271–0.8614
55.88
◦
2
q limit/
-
-
-
26 ≤ h ≤ 26
10 ≤ k ≤ 11
21 ≤ l ≤ 21
-16 ≤ h ≤ 16
-18 ≤ k ≤ 18
-22 ≤ l ≤ 22
29235
Total data collected
21126
Independent reflections
6346
0.0417
5293
6346/0/303
1.076
0.0324
0.0783
0.809, -0.718
5742
0.1289
3537
5742/0/541
1.023
0.0557
0.1136
0.466, -0.455
7686
0.0224
7361
7686/2/382
1.098
0.0270
0.0712
0.889, -0.287
3751
0.0151
3556
3751/0/239
1.140
0.0263
0.0733
0.453, -0.585
R
int
Observed reflections
Data/restraints/parameters
Goodness-of-fit
2
2
R
1
[F
wR [F
Largest peak, hole/e A˚
o
≥ 2s(F
o
o
)]
o
2
2
2
≥ -3s(F
)]
-
3
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Table 2 Selected interatomic distances ( A˚ ) for 2, 4, 7b, and 8a
For samples of 4 dissolved in toluene-d
8
that were sealed under
an atmosphere of dinitrogen, the initially deep green solutions
300 K) turned to red-brown (reversibly) upon cooling below
50 K; conversely, only deep green solutions were observed over
this temperature range for samples that had been thoroughly
b
c
d
2
4
7b
8
(
2
Ru–O
Ru–P
2.2204(15)
2.3421(6)
2.4508(6)
1.873(2)
2.147(6), 2.151(6)
2.360(2), 2.370(3)
1.996(7), 1.994(7)
1.763(8), 1.797(9)
1.307(10), 1.291(10)
N/A
N/A
2.3081(5)
2.3102(6)
1.820(2)
1.333(3)
2.3090(7)
2.103(2)
1.826(2)
1.337(2)
3
1
1
Ru–X
degassed. In tracking the P{ H} NMR behavior of 4 under
similar conditions (223 K), a single sharp resonance (52.1 ppm,
Dn1/2 = 9 Hz) was observed for samples prepared under dinitrogen
(cf. 50.1 ppm, Dn = 213 Hz, 300 K); conversely, two equal-
i
2
Pr P–C
O–C
1.228(3)
a
b
X = Cl (2), N (4), Si (7b), and B (8); N/A = not applicable. N–N =
1
/2
1
.131(8) A˚ ; C1–C2 = 1.515(12) A˚ and 1.519(12) A˚ ; C2–C3 = 1.385(12) A˚
31
1
intensity P{ H} NMR resonances (52.0 ppm, Dn1/2 = 10 Hz;
◦
◦
c
and 1.377(13) A˚ ; Ru–N–N = 165.5(7) and 163.5(6) . Ru–H distances
fixed at 1.55 A˚ during refinement; Ru–H ◊ ◊ ◊ Si 2.12 A˚ and 2.14 A˚ (measured
in final refined structure); Si–O = 1.7053(16) A˚ ; C1–C2 = 1.507(3) A˚ ; C2–
3
9.1 ppm, Dn1/2 = 65 Hz) were observed for degassed samples
of 4 under similar conditions. We are hesitant to provide a
definitive interpretation of these temperature-dependent features.
However, it is plausible that such behavior may be attributable
in part to a dynamic equilibrium involving isomers of 4 and the
C3 = 1.360(3) A˚ . Ru–H = 1.58(2) A; B–H = 1.51(2) A; B–O = 1.437(3) A;
d
˚
˚
˚
C1–C2 = 1.506(3) A˚ ; C2–C3 = 1.363(3) A˚ .
mononuclear complexes 3 and/or 3·N
2
, whereby the position of
this equilibrium is dependent both on temperature and on the
3
2
(l-N )) was ultimately achieved by use of single-crystal X-ray
2
diffraction techniques (Fig. 2). Given the stereogenic nature of
the ruthenium centers in 4, this dinuclear complex can exist in
12
availability of dissolved dinitrogen. Additional contributions
to the observed temperature-dependent NMR spectral features
arising from restricted rotation about the Ru–N–N–Ru axis in 4
cannot be discounted.
C
s
- and C
was subjected to X-ray diffraction analysis corresponds to the
-symmetric isomer, the broadness observed in the NMR spectra
2
-symmetric forms. While the crystalline sample that
C
2
Although the target complex 3 has not been observed directly,
the ability of 4 to serve as a reactive source of 3 was demonstrated
upon exposure to an atmosphere of CO, or two equivalents of
PhCN (Scheme 2). In both cases, the corresponding 3·L adduct
of 4 at 300 K may be attributable in part to rapid exchange
between isomeric forms of 4. Compound 4 represents a rare
example of a crystallographically characterized (h -C
complex featuring a bridging dinitrogen ligand.
5
5
R
5
)RuL
n
1
c,10
The Ru–N
(
5a, L = CO, 93%; 5b, L = PhCN, 91%) was obtained and struc-
˚ ˚ ˚ ˚
(
1.996(7) A and 1.994(7) A) and N–N (1.131(8) A; cf. 1.0977 A in
10b
turally characterized. The observation of nearly identical C–O
free N
N
2
) distances in 4 compare well with those of [(CpRuP
2
)
2
(m-
-
1
2
+
11
stretching frequencies in the IR spectra of 5a (i.e. 3·CO; 1903 cm )
2
)] dications reported by Valerga and co-workers, and sug-
i
-1 4d
and Cp*Ru(P Pr Ph)(OCH CF )(CO) (1906 cm ) suggests that
2
2
3
gest that p-back donation from ruthenium to the coordinated
dinitrogen unit is modest in 4. By comparison, the isolable mon-
odentate complex Cp*Ru(PCy
the P,O ligand sets in these complexes have comparable electron-
donating abilities.
3
)(OCH
2
CF ) reported by Caulton
3
et al. apparently does not exhibit a propensity to coordinate
dinitrogen. In contrast to the rather short Ru–O distance observed
4
a
˚
in Cp*Ru(PCy
3
)(OCH
2
CF
˚
3
) (1.992(10) A) the longer Ru–O
˚
distances in 4 (2.147(6) A and 2.151(6) A) suggest that p-donation
from oxygen to ruthenium is negligible in this dinuclear complex,
in keeping with the adduct Cp*Ru(PCy
3
)(OCH
2
CF )(CO) (Ru–O
3
4a
˚
2
.090(3) A).
Scheme 2 Reactions of putative 3 leading to the 3·L adducts 5a,b and 6
(
the indenyl numbering convention is provided for 5).
Having demonstrated that 4 can be exploited as a masked
source of 3, we sought to examine the reactivity of in situ
generated 3 with E–H s-bonds, beginning with H . The reactivity
complexes with
Fig. 2 ORTEP diagram for 4 shown with 50% displacement ellipsoids
and with selected H atoms and the isopropyl methyl groups omitted for
clarity.
2
5
of coordinatively unsaturated (h -C
5
R )RuL
5 n
4
758 | Dalton Trans., 2009, 4756–4765
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2
H has been found to be highly dependent on the nature of
1
3
i
the ancillary ligands. For example, while Cp*RuP Pr
3
(Cl) and
2
+
-
[
Cp*Ru(k -NMe
2
CH
2
CH
2
NMe
2
)] X are apparently unreactive
] X complexes react to give
(s-
3c,14
+
-
towards H
2
,
related [Cp*RuP
] X ; in some cases, non-classical [Cp*RuP
)] X species exist in equilibrium with the dihydride product,
2
+
-
[Cp*RuP
2
(H)
2
2
+
-
H
2
or are detected spectroscopically at low temperatures as reactive
1
c,13
intermediates.
Motivated by the divergent reactivity exhibited
species featuring either homobidentate N- or
P-based ligands, we sought to probe the behavior of the hybrid
hard–soft” chelate complex 3 with H . Upon exposure of a
degassed C solution of 4 to an atmosphere of H at ambient
temperature, the quantitative formation of a single phosphorus-
5
by (h -C
5
R )RuL
n
5
“
2
6
D
6
2
3
1
containing product (6; d P = 65.2, Dn1/2 = 180 Hz, toluene-d
8
,
1
3
00 K) was observed, which also exhibited a somewhat broad H
NMR resonance centered at -5.73 ppm (Dn1/2 = 23 Hz, toluene-
d
8
, 300 K). Our assignment of 6 as a non-classical s-H adduct,
2
rather than a dihydride complex, was made on the basis of the
rather short measured T1(min) relaxation value (17 ms, 218 K,
1
3
1
2
50 MHz) for the dihydrogen ligand in this complex. While H
Scheme 3 Reactions of putative 3 with PhXSiH
Ph; Mes = 2,4,6-trimethylphenyl).
2
and MesBH
2
(X = H or
1
3
and C NMR data collected at 300 K pointed to a C
s
-symmetric
structure for 6, the H NMR spectrum of 6 collected at 223 K is
in keeping with a s-H adduct of 3 possessing C -symmetry; as
1
Ru–H signals (-11.14 and -11.92 ppm) and a Si–H resonance
1
2
1
was observed for solutions of 4 (vide supra), over this temperature
range initial green solutions of 6 (300 K) are transformed reversibly
into brown solutions upon cooling below 253 K. Although we are
hesitant to comment definitively regarding the origins of these
spectroscopic and coloration changes, such phenomena may be
attributable in part to the exchange of free and bound H
process that is slowed on the H NMR time scale at 223 K. By
comparison, Caulton and co-workers have noted that treatment
in the H NMR spectrum of the C
1
-symmetric 7a, whereas a
group was
-symmetric
single resonance (-11.02 ppm) attributable to a Ru(H)
2
1
observed in the H NMR spectrum obtained for the C
s
7b. In the case of 7b, this structural proposal was confirmed
by use of single-crystal X-ray diffraction techniques (Fig. 3).
The crystallographically determined structure of 7b exhibits Ru–
2
in 6; a
1
˚
˚
Si (2.3102(6) A) and Si–O (1.7053(16) A) distances that are in
4c
keeping with those found in related complexes featuring bidentate
i
2
2
=
16
of Cp*Ru(P Pr
H
Cp*Ru(P Pr
produced HOCH
2
Ph)(OCH
2
CF
3
) with less than 2 equivalents of
under similar conditions afforded the dihydride complex
Ru(k -SiPh
2
OC
5
H
4
N) and Ru(k -SiPh
2
OC(Me) O) ligands. In
contrast to 8 (vide infra), the somewhat long Ru–H ◊ ◊ ◊ Si contacts
2
i
˚
˚
Ph)(OCH
CF
was observed for Cp*Ru(P Pr
liberates H upon exposure to vacuum; as a result, we have thus
2
CF
3
)(H)
2
, while the addition of excess H
2
observed in the solid state structure of 7b (ca. 2.12 A and 2.14 A),
2
i
2
and the trihydride Cp*Ru(P Pr
2
Ph)(H)
3
. As
along with the relatively low measured JSiH values (7a: 9.4 Hz; 7b:
2
3
i
4c
17
Ph)(OCH
2
CF
3
)(H)
2
, compound 6
9.8 Hz), appear to support the description of 7a and 7b as being
2
dihydridosilyl complexes. One plausible mechanism that accounts
2
far not been successful in isolating 6 in an analytically pure form.
The rich and diverse reactivity of coordinatively unsaturated
for the formation of 7a,b involves initial intermolecular Si–H
oxidative addition to 3, followed by Si–O reductive elimination
and finally intramolecular Si–H oxidative addition involving
a tethered silyl ether fragment. However, alternative reaction
18
1
5
ruthenium complexes with organosilanes is well-documented,
2
including reactions leading to isolable h -Si–H adducts as well as
+
-
to unusual [Cp*(PR
ated via double geminal Si–H bond activation of RSiH
context, we became interested in exploring the reactivity of 3 with
silanes (Scheme 3). Treatment of 4 with 2 equivalents of PhSiH
3
)(H)
2
Ru=SiHR] X species that are gener-
3a,b
3
.
In this
3
in benzene resulted in the consumption of the starting complex
after 15 min, along with the formation of three phosphorus-
3
1
containing products ( P NMR; including 7a). Subsequent NMR
analysis of the reaction mixture after a total of 3 h revealed
the quantitative formation of 7a, which in turn was obtained in
9
5% isolated yield. While under similar conditions employing 2
equivalents of Ph SiH the product 7b was formed quantitatively
2
2
after only 15 min and isolated in 95% yield, an intractable prod-
uct mixture was generated under similar conditions employing
Ph SiH. The NMR spectral data obtained for each of 7a and 7b
3
was found to be consistent with the formulation of these products
as arising from overall double geminal Si–H bond activation and
net insertion of a silylene fragment into the Ru–O bond of putative
Fig. 3 ORTEP diagram for 7b shown with 50% displacement ellipsoids
3. Particularly diagnostic was the observation of two unique
and with selected H atoms omitted for clarity.
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sequences including those involving Ru=SiRX (X = H, Ph)
adduct 4. In addition to forming adducts with a range of other two-
19
intermediates cannot be ruled out. The possibility of chemical
electron donor ligands (CO, PhCN and s-H
been observed to engage in Si–H and B–H bond activation chem-
istry. For reactions involving Ph SiH and PhSiH , dihydridosilyl
2
), compound 3 has
exchange involving the Ru–H and Si–H groups of 7a was probed
1
by use of 1D and 2D H EXSY NMR techniques. Notably, the
2
2
3
absence of detectable chemical exchange in this system indicates
that any Si–H elimination/addition processes in 7a must occur at
rates that are slow relative to the dynamic exchange NMR time
scale.
products (7a,b) arising from overall double geminal Si–H bond
activation and net insertion of a silylene fragment into the Ru–O
bond of putative 3 were obtained. While the net insertion of boron
into the Ru–O bond of 3 was also observed in reactions involving
Having documented the facile net extrusion of silylene frag-
ments leading to silicon insertion into the Ru–O bond of 3
MesBH , the corresponding product (8) is perhaps best described
as featuring a tethered dihydridoborate fragment which features
two symmetrical Ru–H–B bridges. Given the relative rarity of
2
(
vide supra), and given the current interest in the metal-mediated
20
activation of monoboranes, we sought to extend our reactivity
n
coordinatively unsaturated Cp*RuL complexes supported by
survey of 3 to include transformations involving mesitylborane
monoanionic, heterobidentate ligands, we are currently exploring
further the synthesis and reactivity of structural variants of 3 and
related derivatives, and will report on the results of these studies
in due course.
21
(
MesBH
2
). Treatment of a dark green solution of 4 with a
resulted in an immediate
stoichiometric equivalent of MesBH
2
3
1
color change to orange-yellow; P NMR analysis of the reaction
mixture after 30 min revealed the clean formation of 8 (Scheme 3),
which in turn was isolated in 82% yield. The assignment of 8
Experimental
as a C
insertion of MesBH
by NMR spectroscopic data (e.g. d H = -13.12, Ru(H)
s
-symmetric dihydroborate complex arising from the net
2
into the Ru–O bond of putative 3 is supported
General considerations
1
31
2
B; d P =
1
1
5
6.4; d B = 59.0), as well as single-crystal X-ray diffraction data
Unless stated otherwise, all manipulations were conducted in
the absence of oxygen and water under an atmosphere of
dinitrogen, either by use of standard Schlenk methods or within a
mBraun glovebox apparatus, utilizing glassware that was oven-
(
Fig. 4). Compound 8 is crystallographically mirror symmetric in
the crystal. While the overall addition of MesBH to 3 furnishes a
Ru(H) B–O core in 8 that is conceptually related to the Ru(H) Si–
2
2
2
◦
ꢀR
O core in 7a,b, some important structural differences were noted
between 7a,b and 8. Whereas significant Ru–H ◊ ◊ ◊ Si interactions
were not detected in 7a,b (vide supra), the notable sharpening
dried (130 C) and evacuated while hot prior to use. Celite
(Aldrich) was oven-dried for 5 d and then evacuated for 24 h
prior to use. The non-deuterated solvents dichloromethane, ben-
zene, and pentane were deoxygenated and dried by sparging
with dinitrogen gas, followed by passage through a double-
column solvent purification system purchased from mBraun Inc.
Dichloromethane was purified over two alumina-packed columns,
while benzene and pentane were purified over one alumina-
packed column and one column packed with copper-Q5 reactant.
1
11
of the hydride H NMR resonance in 8 upon B-decoupling
suggested the presence of some form of B ◊ ◊ ◊ H interaction in
solution. Furthermore, a symmetrical Ru–H–B bridging motif is
˚
apparent in the solid state structure of 8 (Ru–H = 1.58(2) A;
22
˚
B–H = 1.51(2) A).
Benzene-d
6
and toluene-d (Cambridge Isotopes) were degassed
8
by using three repeated freeze–pump–thaw cycles and then dried
˚
over 4 A molecular sieves for 24 h prior to use. All solvents used
˚
within the glovebox were stored over activated 4 A molecular
23
sieves. Each of [Cp*RuCl]
1
4
,
1-diisopropylphosphino-2-indanone
, and mesitylborane were prepared using literature procedures,
and were dried in vacuo for 24 h prior to use. NaN(SiMe
24
25
)
3 2
(
(
Aldrich) was dried in vacuo for 24 h prior to use. Hydrogen
99.999%, UHP Grade) and carbon monoxide gases (99.5%,
chemically pure grade) were obtained from Air Liquide and
were used as received. Whereas PhCN (Aldrich) was degassed
by sparging with dinitrogen gas, PhSiH
by using three repeated freeze–pump–thaw cycles, and Ph
Gelest, shipped under argon) was not degassed; each of these
3
(Strem) was degassed
2
SiH
2
(
˚
reagents was dried over 4 A molecular sieves for 24 h prior to
use. Variable-temperature NMR experiments were conducted on
Fig. 4 ORTEP diagram for 8 (featuring one of the two disordered
components of the isopropyl fragments) shown with 50% displacement
ellipsoids and with selected H atoms omitted for clarity.
1
13
a Bruker AC-250 spectrometer. Unless otherwise stated, H, C,
2
9
31
Si and P NMR characterization data were collected at 300 K on
a Bruker AV-500 spectrometer operating at 500.1, 125.8, 99.4 and
2
02.5 MHz (respectively) with chemical shifts reported in parts per
1
13
29
million downfield of SiMe
in D
4
(for H, C, and Si) or 85% H
3
PO
4
Summary and conclusions
3
1
1
13
2
O (for P). H and C NMR chemical shift assignments are
1
3
1
1
In summary, we have reported herein on the reactivity of the
given on the basis of data obtained from C-DEPT, H– H COSY,
2
1
13
1
13
29
coordinatively unsaturated Cp*Ru(k -P,O) species 3, which is
H– C HSQC, and H– C HMBC NMR experiments. Si NMR
conveniently generated in situ upon loss of N
2
from the dinuclear
chemical shift assignments are given on the basis of data obtained
4
760 | Dalton Trans., 2009, 4756–4765
This journal is © The Royal Society of Chemistry 2009

View Article Online
1
29
1
from H– Si HMQC ( H-coupled experiments were employed
(2 ¥ 3 mL) was then added to wash the solid, and the dark
green supernatant solution was removed carefully via a Pasteur
pipette, leaving a greenish-brown solid. Analysis of P NMR
data collected on the pentane washings indicated relatively minor
amounts of 4 and as such these washings were discarded. The
residue was dried in vacuo, yielding 4 as a greenish-beige powder
1
1
in the determination of JSiH values) as well as H–Si HMBC
J-HMBC experiments were employed in the determination of
SiH values for n > 1) experiments. IR data were collected on
a Bruker VECTOR 22 FT-IR instrument. Raman data were
collected on powdered samples (sealed in glass capillaries under
dry dinitrogen) using a Bruker RFS 100 FT-Raman spectrometer.
Elemental analyses were performed by Canadian Microanalytical
Service Ltd., Delta, British Columbia, Canada.
3
1
(
n
J
(0.074 g, 0.074 mmol, 78%). Anal. Calcd. for C50
H
70
P
2
O
2
N
2
Ru :
2
C 60.32; H 7.09; N 2.82. Found: C 60.34; H 7.10; N 2.10. The
somewhat low N% value determined for 4 is in keeping with some
11 1
other ruthenium dinitrogen complexes. H NMR (500.1 MHz,
00 K, C , under dinitrogen): d 7.38–6.80 (broad m, 4H, aryl-
Hs), 3.35–3.17 (broad m, 2H, CH ), 2.62–2.38 (broad m, 2H,
P(CHMe ), 1.71–0.93 (broad m, 27H, C Me and P(CHMe ).
, under dinitrogen): d
3
6
D
6
Synthesis of 2
2
To a glass vial containing a magnetically stirred suspension of
2
)
2
5
5
)
2 2
3
1
1
[
Cp*RuCl]
4
(0.72 g, 0.66 mmol) in CH
2
Cl
Cl
2
(4 mL) was added a
(4 mL) all at once via
P{ H} NMR (202.5 MHz, 300 K, C
6
D
6
1
solution of 1 (0.66 g, 2.66 mmol) in CH
2
2
50.1 (Dn1/2 = 213 Hz). H NMR (250.1 MHz, 300 K, toluene-
a Pasteur pipette. The addition caused an immediate color change
of the suspension from dark brown to dark red. The vial was
then sealed with a PTFE-lined cap and the solution was stirred
magnetically for 45 min. P NMR data collected on an aliquot
of this solution indicated the quantitative formation of the target
d
8
, degassed sample): d 7.43–6.80 (broad m, 4H, aryl-Hs), 3.28–
3.05 (broad m, 2H, CH ), 2.77–0.53 (broad m, 29H, P(CHMe
and C Me and P(CHMe
toluene-d
, degassed sample): d 44.9 (Dn1/2 = 240 Hz). No
useful information could be derived from the C NMR spectrum
of 4 (125.8 MHz, 300 K, C , under dinitrogen). While no
2
2 2
)
3
1
1
5
5
2
)
2
); P{ H} NMR (101.3 MHz, 300 K,
3
1
8
1
3
complex. The CH
an oily dark red solid. The solid was then triturated with pentane
1.5 mL) and the pentane was removed in vacuo. The residue was
then washed with pentane (2 ¥ 3 mL) and dried in vacuo to yield
2
Cl
2
solvent was then removed in vacuo, yielding
6
D
6
N–N stretch was observed in the IR spectrum of a bulk sample
(
of 4, the corresponding Raman spectrum exhibited a band at
-
1
2042 cm , thereby suggesting the presence of a symmetrical species
2
as an analytically pure orange-pink powder (1.32 g, 2.55 mmol,
in this bulk sample featuring a m-N ligand. Layering of a C
2
6
D
6
9
6%). Anal. Calcd. for C25
H
36POClRu: C 57.74; H 6.98; N 0.00.
solution of 4 with pentane and slow evaporation of the resultant
mixture over the course of approximately two weeks produced a
1
Found: C 57.93; H 6.68; N < 0.3. H NMR (C
6
D
6
): d 7.03–6.91
3
(
(
(
m, 3H, aryl-Hs), 6.62 (d, JHH = 7.0 Hz, 1H, C4–H or C7–H), 5.27
d, JPH = 12.0 Hz, 1H, Pr PC–H), 2.85 (m, 1H, C(H )(H )), 2.64
m, 1H, C(H )(H )), 2.57 (m, 1H, P(CHMe Me )), 1.96 (m, 1H,
Me Me
crystal suitable for X-ray diffraction analysis. Low-temperature
2
i
1
2
a
b
NMR data for 4: H NMR (250.1 MHz, 223 K, toluene-d
8
, under
a
b
a
b
dinitrogen):d 7.19–6.96(m, 4H, aryl-Hs), 3.60–3.15(AB multiplet,
2H, C(H )(H )), 2.86 (m, 1H, P(CHMe Me )), 2.04 (m, 1H,
P(CHMe Me )), 1.78–0.97 (m, 27H, C Me and P(CHMe Me
and P(CHMe
)); P{ H} NMR (101.3 MHz, 223 K, toluene-
, under dinitrogen): d 52.1 (Dn1/2 = 9 Hz); P{ H} NMR
(101.3 MHz, 223 K, toluene-d , degassed sample): d 52.0 (Dn1/2
3
P(CHMe
c
3
d
)), 1.77 (d, J = 1.5 Hz, 15H, C
5
5
), 1.69 (dd, JPH
=
=
a
b
a
b
3
1
1
1
1
2
3
3.0 Hz, JHH = 7.5 Hz, 3H, P(CHMe
a
Me
Me
Me
b
b
d
)), 1.32 (dd, JPH
c
d
5
5
a
b
)
3
3
31
1
7.5 Hz, JHH = 7.0 Hz, 3H, P(CHMe
a
)), 0.86 (dd, JPH
=
c
Me
d
3
3
31
1
4.0 Hz, JHH = 7.0 Hz, 3H, P(CHMe
c
)), 0.58 (dd, JPH
=
d
8
3
13
1
2.0 Hz, JHH = 7.0 Hz, 3H P(CHMe
c
Me
d
)); C{ H} (C
6
D
6
): d
8
=
26.2 (m, C2), 138.5 (d, J = 8.1 Hz, C3a or C7a), 137.8 (d, J =
10 Hz), 39.1 (Dn1/2 = 65 Hz) (1 : 1 ratio).
.3 Hz, C7a or C3a), 127.3 (C5 or C6), 127.0 (aryl-CH), 125.4
i
(
C4 or C7), 124.8 (aryl-CH), 79.8 (C
5
Me
), 27.5 (d, JPC = 11.2 Hz, P(CHMe
6.3 Hz, P(CHMe Me )), 21.6 (P(CHMe
.7 Hz, P(CHMe Me
7.6 (P(CHMe Me
5
), 60.8 ( Pr
2
PC–H), 41.6
Synthesis of 5a
1
1
(
CH
2
c
Me
Me
d
)), 26.4 (d, JPC
)), 20.9 (d, JPC
=
2
1
9
1
1
a
b
a
b
=
Within a glovebox, a J. Young NMR tube was charged with
4 (0.045 g, 0.045 mmol) and 0.8 mL of C . The tube was
2
a
b
)), 18.2 (d, JPC = 4.8 Hz, P(CHMe
c
Me
d
)),
6
D
6
3
1
1
c
d
)), 11.3 (C
5
Me
5
); P{ H} NMR (C
6
D
6
): d
sealed and the solution was mixed by inversion of the tube
several times. The tube containing the resulting deep green solution
was removed from the glovebox, connected to a Schlenk line,
and degassed via three repeated freeze–pump–thaw cycles. An
atmosphere of CO was introduced to the NMR tube, upon which
the solution was observed to change gradually in color to brown
00.5. Slow evaporation of a concentrated benzene solution of
the target complex produced a crystal of 2·0.5C
6
6
H suitable for
X-ray diffraction analysis.
Synthesis of 4
3
1
1
over the course of several min. After 30 min, P and H NMR
data collected on this reaction mixture indicated quantitative
conversion to 5a. Upon removal of solvent and other volatile
materials in vacuo, followed by trituration with pentane (2 ¥
1.5 mL), 5a was isolated as an analytically pure, tan powder
To a glass vial containing a magnetically stirred deep red suspen-
sion of 2 (0.10 g, 0.19 mmol) in benzene (8 mL), was added solid
NaN(SiMe
with a PTFE-lined cap and magnetic stirring was initiated. Over
the course of several seconds, the reaction mixture became dark
green. After 45 min, P NMR data collected on an aliquot of this
3
2
) (0.037 g, 0.20 mmol) all at once. The vial was sealed
(0.043 g, 0.084 mmol, 93%). Anal. Calcd. for C26
61.02; H 6.90; N 0.00. Found: C 61.01; H 6.97; N < 0.3. H
H
35PO
2
Ru: C
3
1
1
3
crude reaction mixture indicated the quantitative formation of 4.
NMR (C
6
D
6
): d 7.22 (m, 1H, C5–H or C6–H), 7.01 (d, JHH
=
ꢀ
R
The solution was filtered through Celite and the benzene solvent
and other volatile materials were removed in vacuo, yielding an
oily dark green solid. The residue was triturated with pentane (2 ¥
7.5 Hz, 1H, C4–H or C7–H), 6.93–6.87 (m, 2H, aryl-Hs), 3.28–
3.17 (m, 2H, C(H
1H, P(CHMe Me
a
)(H
)), 1.59 (d, J = 1.0 Hz, 15H, C
Me
b
)), 2.84 (m, 1H, P(CHMe
a
Me
b
)), 2.01 (m,
c
d
3
5
Me
5
), 1.38 (dd,
3
1
mL), after which the pentane was removed in vacuo. Pentane
J
PH = 16.0 Hz, JHH = 7.0 Hz, 3H, P(CHMe
a
b
)), 1.23 (dd,
This journal is © The Royal Society of Chemistry 2009
Dalton Trans., 2009, 4756–4765 | 4761

View Article Online
3
3
J
PH = 11.5 Hz, JHH = 7.0 Hz, 3H, P(CHMe
c
3
Me
d
)), 1.02–0.94
for 18 h. For freshly prepared solutions of 6, removal of volatiles
1
1
(
2
(
m, 6H, P(CHMe
a
Me
b
) and P(CHMe
c
Me
d
)); C{ H} (C
6
D
6
): d
in vacuo led to the quantitative conversion of 6 back to 4 (as
2
2
31
08.6 (d, JPC = 19.1 Hz, CO), 200.8 (d, JPC = 21.3 Hz, C2), 146.7
determined by P NMR analysis of a C
6
6
D solution of the dried
C3a or C7a), 139.7 (d, J = 8.6 Hz, C7a or C3a), 127.2 (C5 or
solid that had been prepared under an atmosphere of dinitrogen).
1
3
C6), 124.4 (aryl-CH), 120.0 (aryl-CH), 116.4 (C4 or C7), 99.9 (d,
H NMR (500.1 MHz, 300 K, toluene-d
8
): d 7.20 (t, JHH
=
1
3
3
J
PC = 48.8 Hz, C3), 94.1 (C
5
Me
5
), 38.6 (d, JPC = 8.8 Hz, C1),
7.5 Hz, 1H, C5–H or C6–H), 7.01 (d, JHH = 7.5 Hz, 1H, C4–
1
1
3
2
7.0 (d, JPC = 18.6 Hz, P(CHMe
c
Me
d
)), 24.2 (d, JPC = 35.6 Hz,
H or C7–H), 6.93 (d, JHH = 7.0 Hz, 1H, C7–H or C4–H), 6.86
2
3
P(CHMe
a
Me
b
)), 19.8 (d, JPC = 6.3 Hz, P(CHMe
c
Me
d
)), 19.8 (d,
(t, JHH = 7.0 Hz, 1H, C6–H or C5–H), 3.25 (s, 2H, CH
2
3
), 2.45
2
J
PC = 6.3 Hz, P(CHMe
a
Me
b
) or P(CHMe
c
Me
d
)), 18.9–18.8 (m,
(m, 2H, P(CHMe
a
Me
b
), 1.64 (s, 15H, C
5
Me
5
), 1.19 (dd, JPH
=
3
3
P(CHMe
(
1
a
3
Me
b
1
) and either P(CHMe
c
Me ) or P(CHMe
): d 63.0. FTIR (CsI; cm ) n(CO):
d
a
Me
b
)), 10.3
13.5 Hz, JHH = 7.0 Hz, 6H, P(CHMe
a
Me
b
)), 1.11 (dd, JPH
=
1
-1
3
C
903.
5
Me
5
); P{ H} NMR (C
6
D
6
16.0 Hz, JHH = 6.5 Hz, 6H, P(CHMe
a
Me
b
)), -5.73 (broad s,
)); C{ H} (125.8 MHz, 300 K, toluene-
1
3
1
Dn1/2 = 23 Hz, 2H, Ru(H
): d 199.9 (m, C2), 146.8 (m, C3a or C7a), 139.9 (m, C7a or
C3a), 126.8 (C5 or C6), 124.2 (C4 or C7), 119.7 (C6 or C5),
2
d
8
Synthesis of 5b
To a glass vial containing a magnetically stirred solution of 4
(
0
in the color of the solution from dark green to orange-
red was observed upon the addition of PhCN. The vial was
sealed with a PTFE-lined cap, and the solution was stirred
for 30 min. P NMR data collected on an aliquot of this
solution indicated quantitative conversion to 5b. The solvent and
other volatile materials were removed in vacuo, yielding an oily
dark red-brown solid. The residue was triturated with pentane
3
1
16.3 (C7 or C4), 81.1 (C
(broad m, P(CHMe Me )), 19.6–19.3 (broad m, P(CHMe
); P{ H} NMR (202.5 MHz, 300 K, toluene-d
d 65.2 (broad m, Dn1/2 = 180 Hz). The T1(min) relaxation time
value (218 K, 17 ms, 250 MHz) associated with the s-H unit
in 6 was obtained by using the inversion-recovery technique.
5
Me
5
), 38.6 (d, JPC = 8.4 Hz, C1), 24.5
Me )),
):
a
b
a
b
3
1
1
0.11 g, 0.11 mmol) in benzene was added PhCN (0.025 mL,
.24 mmol) all at once via an Eppendorf pipette. A change
11.1 (C
5
Me
5
8
2
13
Variable-temperature behavior of 6. The initially green toluene
solution of 6 observed at 300 K becomes brown in appearance
3
1
1
(reversibly) upon cooling below 253 K. H NMR (250.1 MHz,
223 K, toluene-d
multiplet, 2H, C(H
1H, P(CHMe Me
P(CHMe Me ) and P(CHMe
2H, Ru(H
8
): d 7.34–6.94 (m, 4H, aryl-Hs), 3.40–3.15 (AB
)(H )), 2.53 (m, 1H, P(CHMe Me )), 1.98 (m,
)), 1.63 (s, 15H, C Me ), 1.42–0.83 (m, 12H,
Me
)), -6.40 (broad s, Dn1/2 = 51 Hz,
): d
a
b
a
b
(
2 ¥ 1.5 mL), and the pentane was removed in vacuo to yield 5b as an
c
d
5
5
analytically pure, orange-brown powder (0.12 g, 0.20 mmol, 91%).
Anal. Calcd. for C32
C 65.49; H 6.64; N 2.31. H NMR (C
1
3
7
a
b
3
c
d
1
1
H
40PONRu: C 65.49; H 6.88; N 2.39. Found:
2
)); P{ H} NMR (101.3 MHz, 223 K, toluene-d
8
1
3
6
D
6
): d 7.25 (t, JHH = 7.5 Hz,
72.2 (Dn1/2 = 20 Hz).
H, C5–H or C6–H), 7.16 (m, 1H, C4–H or C7–H), 7.02–6.97 (m,
H, 2 NC–aryl-Hs and either C7–H or C4–H), 6.85 (t, JHH
.0 Hz, 1H, C6–H or C5–H), 6.81 (t, JHH = 7.0 Hz, 1H, NC–aryl-
3
=
Synthesis of 7a
3
3
H), 6.64 (apparent t, JHH = 7.5 Hz, 2H, NC–aryl-Hs), 3.44–3.35
To a glass vial containing a magnetically stirred deep green
suspension of 4 (0.020 g, 0.020 mmol) in C (2 mL), was
added PhSiH (0.0051 mL, 0.041 mmol) via a microsyringe. The
(
1
broad s, 2H, C(H
4H, P(CHMe Me
P(CHMe Me
)); C{ H} (C
a
)(H
b
)), 1.74 (s, 15H, C
Me ) and P(CHMe
): d 199.8 (d, JPC = 23.7 Hz, C2),
5
Me
5
), 1.43–1.25 (m,
6
D
6
a
b
) and P(CHMe
c
d
a
Me ) and
b
3
1
3
1
2
c
d
6
D
6
vial was sealed with a PTFE-lined cap and magnetic stirring was
initiated. Over the course of several seconds, the reaction mixture
1
49.0 (C3a or C7a), 139.0 (d, J = 7.8 Hz, C7a or C3a), 131.6–131.4
3
1
(
m, NC–aryl-CHs), 129.0 (NC–aryl-CHs), 126.7 (C5 or C6), 123.9
became an orange-yellow homogeneous mixture. After 3 h,
P
(
9
C4 or C7), 118.7 (C6 or C5), 115.9 (C7 or C4), 113.7 (NC–aryl-C),
NMR data collected on an aliquot of this crude reaction mixture
indicated the quantitative formation of 7a. The benzene solvent
and other volatile materials were removed in vacuo, yielding
an oily orange solid. The residue was triturated with pentane
(2 ¥ 1 mL), after which the pentane was removed in vacuo to
yield 7a as an orange powder (0.023 g, 0.038 mmol, 95%). Anal.
1
3
8.5 (d, JPC = 41.6 Hz, C3), 82.8 (C
5
Me
Me
)), 10.8 (C
5
), 39.3 (d, JPC = 8.1 Hz,
C1), 20.9–19.2 (broad m, P(CHMe
P(CHMe
(
a
b
) and P(CHMe
c
Me ) and
d
3
1
1
a
Me
b
) and P(CHMe
c
Me
d
5
Me
5
); P{ H} NMR
C
6
D
6
): d 53.9.
Calcd. for C31
H
43POSiRu: C 62.91; H 7.32; N 0.00. Found: C
Synthesis of 6
Within a glovebox, a J. Young NMR tube was charged with
1
62.95; H 7.04; N < 0.3. H NMR (C
6
D ): d 8.18–8.15 (m, 2H,
6
Si–aryl-Hs), 7.42–7.36 (m, 3H, 2 Si–aryl-Hs and aryl-H), 7.26 (m,
1H, Si–aryl-H), 7.16 (m, 1H, aryl-H), 6.96–6.89 (m, 2H, aryl-Hs),
4
(0.020 g, 0.020 mmol) and 0.8 mL of toluene-d . The tube
8
was sealed and the solution was mixed by inversion of the
tube several times. The tube containing the resulting deep green
solution was removed from the glovebox, connected to a Schlenk
line, and degassed via three repeated freeze–pump–thaw cycles.
6.61 (m, 1H, Si–H), 3.26–2.98 (m, 2H, C(H
2H, P(CHMe Me ) and P(CHMe Me )), 1.73 (s, 15H, C
1.09–1.00 (m, 9H, P(CHMe Me ) and P(CHMe Me )), 0.94 (dd,
PH = 16.0 Hz, JHH = 7.0 Hz, 3H, P(CHMe Me )), -11.14 (d,
a
)(H
b
)), 2.74–2.61 (m,
a
b
c
d
5
Me ),
5
a
b
c
d
3
3
J
c
d
Introduction of an atmosphere of H
2
to a degassed solution of 4
1H, J = 34.0 Hz, Ru–H
a
), -11.92 (apparent dd, 1H, J = 32.5 Hz,
1
3
1
2
caused the solution to lighten gradually in color from deep green
J = 5.0 Hz, Ru–H
b
); C{ H} (C
6
D
6
): d 177.0 (d, JPC = 8.6 Hz,
3
1
to lime green over the course of several min. After 20 min,
P
C2), 146.5 (C3a or C7a), 145.5 (Si–aryl-C), 135.2–135.1 (m, Si–
aryl-CHs and either C7a or C3a), 128.9 (Si–aryl-CH), 128.2–128.1
1
and H NMR data collected on this reaction mixture indicated
the quantitative conversion of 4 into 6. Whereas solutions of 6
prepared in this manner were found to be stable for a minimum of
(Si–aryl-CHs), 126.2 (aryl-CH), 123.5 (aryl-CH), 122.5 (aryl-CH),
1
120.2 (aryl-CH), 103.1 (d, JPC = 54.1 Hz, C3), 95.6 (C
5
Me
5
), 42.7
Me )),
3
1
3
1
8
h, some decomposition ( P NMR) was detected upon standing
(d, JPC = 7.7 Hz, C1), 29.1 (d, JPC = 25.9 Hz, P(CHMe
c
d
4
762 | Dalton Trans., 2009, 4756–4765
This journal is © The Royal Society of Chemistry 2009

View Article Online
1
3
2
2
7.9 (d, JPC = 27.2 Hz, P(CHMe
a
Me
b
)), 20.7 (P(CHMe
Me ) or P(CHMe
Me ) or P(CHMe
PC = 5.9 Hz, P(CHMe
Me )), 11.6 (C Me
c
Me
d
)),
J
HH = 8.0 Hz, 1H, C4–H or C7–H), 7.22 (m, 1H, aryl-H), 7.02–
2
0.4 (d,
J
PC = 7.9 Hz, P(CHMe
a
b
a
Me
b
d
d
)
)
)
7.00 (m, 2H, aryl-Hs), 6.93 (s, 2H, B–aryl-H), 3.31 (s, 2H, CH ),
2.65 (m, 2H, P(CHMe
2
or P(CHMe
or P(CHMe
or P(CHMe
NMR (C
c
Me
Me
Me
d
)), 20.3 (P(CHMe
a
b
c
c
Me
a
Me )), 2.62 (s, 6H, B–aryl o-Me), 2.33 (s,
b
2
a
b
)), 19.0 (d,
J
Me
3H, B–aryl p-Me), 1.60 (d, J = 1.5 Hz, 15H, C
5
Me ), 1.22–1.15
5
3
1
1
2
a
b
) or P(CHMe
a
b
5
5
); P{ H}
(m, 12H, P(CHMe
a
Me
b
)), -13.12 (broad d, JPH = 13.5 Hz, 2H,
2
9
1
1
29
13
1
2
6
D
6
): d 67.4; Si{ H} NMR (C
6
D
6
): d 60.4 ( H– Si
Ru–H–B); C{ H} NMR (C
6
D
6
): d 176.3 (d, JPC = 10.8 Hz, C2),
1
1
1
29
HMBC/HMQC), JSiH = 199.7 Hz ( H-coupled H– Si HMQC),
146.3 (C3a or C7a), 136.8 (o-B–aryl-C), 135.7 (d, J = 6.0 Hz,
C7a or C3a), 135.3 (p-B–aryl-C), 128.1 (B–aryl-CH), 126.2 (aryl-
CH), 123.6 (aryl-CH), 123.1 (aryl-CH), 122.1 (C4 or C7), 101.9
2
J
SiH = 9.4 Hz (J-HMBC).
1
3
(
d, JPC = 33.7 Hz, C3), 92.4 (C
5
Me
5
), 42.1 (d, JPC = 6.4 Hz,
Synthesis of 7b
1
C1), 27.9 (d, JPC = 25.9 Hz, P(CHMe
a
Me )), 22.9 (B–aryl o-Me),
b
2
To a glass vial containing a magnetically stirred deep green
suspension of 4 (0.060 g, 0.060 mmol) in benzene (8 mL), was
added Ph
21.3 (B–aryl p-Me), 21.2 (P(CHMe
a
Me
b
)), 19.5 (d, JPC = 5.0 Hz,
3
1
1
P(CHMe
a
Me
b
)), 11.2 (C
5
Me
5
); P{ H} NMR (C
6
D
6
): d 56.4;
1
1
1
2
SiH
2
(0.025 mL, 0.13 mmol) via an Eppendorf pipette.
B{ H} NMR (C
6
D
6
): d 59.0 (broad). Storage of a concentrated
◦
The vial was sealed with a PTFE-lined cap and magnetic stirring
was initiated. Over the course of several seconds, the reaction
mixture became an orange-yellow homogeneous mixture. After
pentane solution of 8 at -37 C provided a suitable crystal for
single-crystal X-ray diffraction studies.
3
1
1
5 min, P NMR data collected on an aliquot of this crude
Crystallographic characterization of 2·0.5C
6
6
H and 4
reaction mixture indicated the quantitative formation of 7b.
The benzene solvent and other volatile materials were removed
in vacuo, yielding an oily orange solid. The residue was triturated
with pentane (2 ¥ 1 mL), after which the pentane was removed
in vacuo to yield 7b as a peach powder (0.079 g, 0.12 mmol, 95%).
Crystallographic data for these complexes were obtained at
173(±2) K on a Nonius KappaCCD 4-Circle Kappa FR540C
diffractometer using a graphite-monochromated Mo Ka (l =
˚
0.71073 A) radiation, employing samples that were mounted in
Anal. Calcd. for C37
C 66.13; H 6.89; N < 0.3. H NMR (C
H
47POSiRu: C 66.53; H 7.09; N 0.00. Found:
inert oil and transferred to a cold gas stream on the diffractometer.
Cell parameters were initially retrieved by using the COLLECT
software (Nonius), and refined with the HKL DENZO and
1
6
6
D ): d 8.03–8.01 (m, 4H,
3
Si–aryl-Hs), 7.41 (d, JHH = 8.0 Hz, 1H, C4–H or C7–H), 7.36
3
26
(
apparent t, JHH = 7.0 Hz, 4H, Si–aryl-Hs), 7.27–7.23 (m, 2H, Si–
SCALEPACK software. Data reduction and absorption correc-
aryl-Hs), 7.13 (m, 1H, aryl-H), 6.96–6.92 (m, 2H, aryl-Hs), 3.17 (s,
H, CH ), 2.63 (m, 2H, P(CHMe Me )), 1.67 (s, 15H, C Me ), 1.09
)), 0.94 (dd,
)), -11.02 (d, 2H,
tion (multi-scan) were also performed with the HKL DENZO
and SCALEPACK software. The structures were solved by using
2
2
a
b
5
5
3
3
27
(
dd, JPH = 17.0 Hz, JHH = 7.0 Hz, 6H, P(CHMe
a
Me
b
the direct methods package in SIR-97, and refined by use of
3
3
28
J
J
PH = 15.5 Hz, JHH = 7.0 Hz, 6H, P(CHMe
a
Me
b
the SHELXL97-2 program, employing full-matrix least-squares
2
13
1
2
2
2
2
PH = 32.5 Hz, Ru–Hs); C{ H} (C
6
D
6
): d 177.1 (d, JPC = 9.1 Hz,
procedures (on F ) with R
1
based on F
o
≥ 2s(F
o
) and wR based
2
2
2
C2), 146.5 (C3a or C7a), 146.2 (Si–aryl-C), 135.9 (Si–aryl-CHs),
35.1 (d, J = 6.9 Hz, C7a or C3a), 128.4 (Si–aryl-CHs), 127.4 (Si–
aryl-CHs), 126.4 (aryl-CH), 123.5 (aryl-CH), 122.4 (C5 or C6),
on F
o
≥ -3s(F ). Anisotropic displacement parameters were
o
1
employed throughout for the non-H atoms. For 2·0.5C
6
H , the
6
i
Pr PC–H position was located in the Fourier difference map and
2
1
1
20.3 (C4 or C7), 103.1 (d, JPC = 52.3 Hz, C3), 96.1 (C
5
Me
5
), 42.8
Me )),
)), 11.6
):
refined freely. Otherwise, all H-atoms were added at calculated
positions and refined by using a riding model employing isotropic
displacement parameters based on the isotropic displacement
parameter of the attached atom. Additional crystallographic
3
1
(
2
d, JPC = 7.4 Hz, C1), 28.6 (d, JPC = 26.9 Hz, P(CHMe
a
b
2
0.3 (P(CHMe
a
Me
b
)), 19.5 (d, JPC = 5.8 Hz, P(CHMe
a
Me
b
3
1
1
29
1
(
C
5
Me
5
); P{ H} NMR (C
6
D
6
): d 65.1; Si{ H} NMR (C
6
D
6
1
29
2
d 57.4 ( H– Si HMBC), JSiH = 9.8 Hz (J-HMBC). A crystal
of 7b suitable for X-ray diffraction analysis was grown from a
information is provided in the deposited CIFs: 2·0.5C
6
H (CCDC
6
654073) and 4 (CCDC 654074).† ORTEP diagrams featured in
◦
concentrated pentane solution at -35 C.
the manuscript were prepared by use of ORTEP-3 for Windows
8
version 1.074.
Synthesis of 8
Crystallographic characterization of 7b and 8
To a glass vial containing a magnetically stirred deep green
suspension of 4 (0.035 g, 0.035 mmol) in benzene (2 mL), was
Crystallographic data for these complexes were obtained at
added solid MesBH
vial was sealed with a PTFE-lined cap and magnetic stirring was
initiated. Over the course of several seconds, the reaction mixture
became orange-yellow in color. After 30 min, P NMR data
collected on an aliquot of the crude reaction mixture indicated
the quantitative formation of 8. The benzene solvent and other
volatile materials were removed in vacuo, yielding an oily orange-
yellow solid. The residue was triturated with pentane (2 ¥ 1 mL),
after which the pentane was removed in vacuo to yield 8 as an
analytically pure orange-yellow powder (0.036 g, 0.058 mmol,
2
(0.0093 g, 0.071 mmol) all at once. The
193(±2) K on a Bruker PLATFORM/SMART 1000 CCD diffrac-
˚
tometer using a graphite-monochromated Mo Ka (l = 0.71073 A)
radiation, employing a sample that was mounted in inert oil and
transferred to a cold gas stream on the diffractometer. Programs
for diffractometer operation, data collection, data reduction, and
absorption correction (including SAINT and SADABS) were
supplied by Bruker. For 7b the structure was solved by use of
direct methods, while for 8 a Patterson search/structure expansion
was employed. Refinement was carried by use of the SHELXL97-2
3
1
2
8
2
program, employing full-matrix least-squares procedures (on F )
2
2
2
2
8
2%). Anal. Calcd. for C34
H
48POBRu: C 66.30; H 7.86; N 0.00.
with R
1
based on F
o
≥ 2s(F
o
) and wR
2
based on F
o
≥ -3s(F
o
).
1
Found: C 66.30; H 7.56; N < 0.3. H NMR (C
6
D
6
): d 7.70 (d,
Compound 8 features crystallographically imposed C
s
-symmetry,
This journal is © The Royal Society of Chemistry 2009
Dalton Trans., 2009, 4756–4765 | 4763

View Article Online
such that the asymmetric unit contains half of a molecular
formula unit. The solution and refinement of 8 was successfully
carried out by employing a disorder model involving the isopropyl
fragments. Anisotropic displacement parameters were employed
throughout for the non-H atoms. All Ru–H positions were located
in the Fourier difference map and refined; for 7b the Ru–H
Braunstein, Chem. Rev., 2006, 106, 134; (b) V. C. Gibson and S. K.
Spitzmesser, Chem. Rev., 2003, 103, 283; (c) S. D. Ittel, L. K. Johnson
and M. Brookhart, Chem. Rev., 2000, 100, 1169; (d) A. Bader and E.
Lindner, Coord. Chem. Rev., 1991, 108, 27.
7 For a preliminary account of this work, see: M. A. Rankin, K. D. Hesp,
G. Schatte, R. McDonald and M. Stradiotto, Chem. Commun., 2008,
2
50.
8
ORTEP-3 for Windows version 1.074: L. J. Farrugia, J. Appl. Crystal-
logr., 1997, 30, 565.
˚
distances fixed at 1.55 A, while for 8 no such restraints were
applied. All other H-atoms were added at calculated positions and
refined by use of a riding model employing isotropic displacement
parameters based on the isotropic displacement parameter of the
attached atom. The final refined value of the absolute structure
parameter (-0.024(19)) supported that the absolute structure
9 T. Braun, P. Steinert and H. Werner, J. Organomet. Chem., 1995, 488,
69.
0 For selected reports featuring the crystallographic characterization of
alternative (L Ru) ) complexes, see: (a) K. Abdur-Rashid, D. G.
1
1
n
2
·(m-N
2
Gusev, A. J. Lough and R. H. Morris, Organometallics, 2000, 19, 1652;
(b) R. A. T. M. Abbenhuis, I. del R ´ı o, M. M. Bergshoef, J. Boersma, N.
Veldman, A. L. Spek and G. van Koten, Inorg. Chem., 1998, 37, 1749,
and references cited therein.
29
for 7b had been chosen correctly. Additional crystallographic
information is provided in the deposited CIFs (7b, CCDC
1
1 H. Aneetha, M. Jim e´ nez-Tenorio, M. C. Puerta, P. Valerga and K.
Mereiter, Organometallics, 2002, 21, 628.
654072; 8, CCDC 719567).† The ORTEP diagrams featured in
the manuscript was prepared by use of ORTEP-3 for Windows
12 The temperature-dependent coordination of dinitrogen to
i
8
3
Cp*OsP Pr (Cl) had been documented previously: P. B. Glaser
version 1.074.
and T. D. Tilley, Eur. J. Inorg. Chem., 2001, 2747.
3 (a) D. M. Heinekey and W. J. Oldham Jr., Chem. Rev., 1993, 93, 913;
1
(
(
1
b) P. G. Jessop and R. H. Morris, Coord. Chem. Rev., 1992, 121, 155;
c) R. H. Crabtree, M. Lavin and L. Bonneviot, J. Am. Chem. Soc.,
Acknowledgements
986, 108, 4032.
Acknowledgement is made to the Natural Sciences and Engineer-
ing Research Council of Canada (including a Discovery Grant
for M. S., a Postgraduate Scholarship for M. A. R., and a Canada
Graduate Scholarship for K. D. H.), the Canada Foundation for
Innovation, the Nova Scotia Research and Innovation Trust Fund,
and Dalhousie University for their generous support of this work.
We also thank Dr Michael Lumsden and Dr Katherine Robertson
1
1
4 C. Gemel, K. Mereiter, R. Schmid and K. Kirchner, Organometallics,
1997, 16, 5601.
5 (a) R. N. Perutz and S. Sabo-Etienne, Angew. Chem., Int. Ed., 2007, 46,
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1
1
(
Atlantic Region Magnetic Resonance Center, Dalhousie) for
7 For discussions regarding the interpretation of JSiH values, see: S. K.
Ignatov, N. H. Rees, B. R. Tyrrell, S. R. Dubberley, A. G. Razuvaev, P.
Mountford and G. I. Nikonov, Chem.–Eur. J., 2004, 10, 4991.
8 Alternatively, the direct addition of Si–H across the O–Ru linkage in
assistance in the acquisition of NMR data.
1
3
may occur en route to 7a,b, in keeping with the reactivity observed
Notes and References
2 + -
between phosphinothiolate salts of the type [Cp*Ir(k -P,S)] X and
silanes: K. D. Hesp, R. McDonald, M. J. Ferguson and M. Stradiotto,
J. Am. Chem. Soc., 2008, 130, 16394.
1
For selected reviews, see: (a) C. Bruneau, J.-L. Renaud and B.
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19 The transformation of rhodium–silylene (L
n
(H)
2
=
2
Rh SiR ) species,
(
c) M. Jim e´ nez-Tenorio, M. C. Puerta and P. Valerga, Eur. J. Inorg.
formed via double geminal Si–H bond activation, into L
(H)Rh–SiR –
n 2
Chem., 2004, 17; (d) H. Nagashima, H. Kondo, T. Hayashida, Y.
Yamaguchi, M. Gondo, S. Masuda, K. Miyazaki, K. Matsubara and
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McNally and A. J. Smallridge, Adv. Inorg. Chem., 1990, 30, 1.
OCHR¢ species related to 7a,b has been put forth as a key step in a
2
recently proposed ketone hydrosilylation mechanism: N. Schneider, M.
Finger, C. Haferkemper, S. Bellemin-Laponnaz, P. Hofmann and L. H.
Gade, Angew. Chem., Int. Ed., 2009, 48, 1609.
2
2
3
4
For an example in which the intermediacy of such Cp*Ru(k -L,X)
20 Selected reviews: (a) H. Braunschweig, C. Kollann and F. Seeler,
Struct. Bonding, 2008, 130, 1; (b) D. L. Kays and S. Aldridge, Struct.
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1
29, 290, and references cited therein.
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4
0, 712; (b) P. B. Glaser and T. D. Tilley, J. Am. Chem. Soc., 2003, 125,
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1
Chem. Commun., 1988, 278.
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S. A. Jackson, O. Eisenstein and K. G. Caulton, Inorg. Chem., 1995,
21 For recent reports documenting the reactivity of ruthenium complexes
with MesBH , see: (a) K. D. Hesp, M. A. Rankin, R. McDonald and M.
2
3
4, 488; (b) C. C. Bickford, T. J. Johnson, E. R. Davidson and K. G.
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2
725.
22 For some recent reports of crystallographically characterized com-
plexes featuring a Ru–H–B bridging motif, see: (a) M. A. Rankin,
D. F. MacLean, R. McDonald, M. J. Ferguson, M. D. Lumsden and
M. Stradiotto, Organometallics, 2009, 28, 74; (b) G. C. Rudolf, A.
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5
Selected recent reports and reviews: (a) H. Gr u¨ tzmacher, Angew. Chem.,
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185; (c) E. J. Derrah, D. A. Pantazis, R. McDonald and L. Rosenberg,
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3
5, 44.
2
6
The utility of k -P,O-phosphinoenolate ligation has been demonstrated
in alternative classes of reactive transition metal complexes: (a) P.
4
764 | Dalton Trans., 2009, 4756–4765
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View Article Online
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2
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This journal is © The Royal Society of Chemistry 2009
Dalton Trans., 2009, 4756–4765 | 4765