Probing the dynamics and reactivity of a stereochemically nonrigid Cp*Ru(h)(κ2-P,carbene) complex

Article abstract of DOI:10.1021/om800761c

The ability of the coordinatively saturated, 18-electron Cp ^*(H)Ru=CHR complex 1 to serve as a masked source of the coordinatively unsaturated Cp^z.ast;Ru-CH₂R species 2 via reversible α-hydride elimination was surveyed. Th

Full text of DOI:10.1021/om800761c

74
Organometallics 2009, 28, 74–83
Probing the Dynamics and Reactivity of a Stereochemically
Nonrigid Cp*Ru(H)(K2-P,Carbene) Complex
Matthew A. Rankin,† Darren F. MacLean,† Robert McDonald,‡ Michael J. Ferguson,‡
Michael D. Lumsden,†,§ and Mark Stradiotto*,†
Department of Chemistry, Dalhousie UniVersity, Halifax, NoVa Scotia, Canada B3H 4J3, X-Ray
Crystallography Laboratory, Department of Chemistry, UniVersity of Alberta,
Edmonton, Alberta, Canada T6G 2G2, and Atlantic Region Magnetic Resonance Center, Dalhousie
UniVersity, Halifax, NoVa Scotia, Canada B3H 4J3
ReceiVed August 6, 2008
The ability of the coordinatively saturated, 18-electron Cp*(H)RudCHR complex 1 to serve as a masked
source of the coordinatively unsaturated Cp*Ru-CH2R species 2 via reversible R-hydride elimination
was surveyed. The rate constant for this dynamic process (300 K, C6D6) was measured to be 59 ( 1 s-1,
on the basis of data obtained from selective inversion NMR experiments. Exposure of 1 to an atmosphere
of CO or to an equivalent of either PMe3 or PH2Ph afforded the corresponding 2 · L adduct (L ) CO,
98%; PMe3, 93%; PH2Ph, 67%). Treatment of 1 with Ph2SiH2, PhSiH3, Ph2SiClH, or PhSiClH2 afforded
the corresponding net Si-H addition product, 3a-d (82-94%); an NMR spectroscopic investigation of
the analogous reaction of 1 with Ph2SiD2 provided evidence in support of a reaction mechanism involving
previously undocumented Si-H addition across the RudC unit in 1 in the formation of 3a. Addition of
Jutzi’s acid (H(OEt2)2B(C6F5)4) to 1 resulted in the quantitative formation of 4 (the N-C-H cyclometalated
-
variant of [Cp*Ru(κ2-2-NMe2-3-PiPr2-indene)]+B(C6F5)4 ). In monitoring the progress of the reaction of
1 with excess catecholborane (HBcat), evidence for the formation of the B-H addition product 5i was
obtained en route to the isolable (Bcat)RudC species (5, 54%). Conversely, no intermediates were observed
in the reaction of 1 with mesitylborane (MesBH2) leading to the Cp*Ru(P,N) complex 6 (81%), which
features a tethered borane fragment and a Ru-H-B bridge. Crystallographic characterization data are
provided for 2 · PMe3, 3a, 3b, 3d, 5, and 6.
zwitterionic, coordinatively unsaturated species Cp*Ru(κ2-3-
Introduction
PiPr2-2-NMe2-indenide); in the absence of additional coligands,
Coordinatively unsaturated (η5-C5R5)RuLn (η5-C5H5 ) Cp;
this zwitterion rapidly rearranges to the Cp*Ru(H)(κ2-P,C)
η5-C5Me5 ) Cp*) complexes represent appealing targets of
inquiry, owing to their unique reactivity properties.1 Significant
research effort continues to be directed toward documenting the
stoichiometric reactivity of these and other coordinatively
unsaturated complexes, both as a means of augmenting our
understanding of the substrate transformations that can occur
within the coordination sphere of (η5-C5R5)RuLn species and
as an initial step toward the development of new metal-catalyzed
reactivity.1i,2 In this context, one facet of our research program
is focused on the synthesis and reactivity of Cp*Ru complexes
derived from donor-substituted indene ligands.3 We have
reported previously on our efforts to prepare the formally
hydridocarbene complex 1 via double geminal C-H bond
activation involving a ligand NMe group.3f,g Notably, a spec-
troscopic investigation of 1 employing 1D- and 2D-EXSY NMR
techniques provided evidence for the first documented inter-
conversion of Ru(H)dCH (in 1) and Ru-CH2 (in the unob-
served intermediate 2) fragments by way of reversible R-hydride
elimination (Scheme 1).3g,4 Further indirect support for the
viability of 2 was obtained via isolation of the adduct 2 · PHPh2
upon treatment of 1 with PHPh2. Intrigued by these preliminary
observations, we became interested in obtaining rate data for
this reversible R-hydride elimination process, as well as in
exploring further the extent to which the intermediate 2 might
play a role in the chemistry observed for the stereochemically
* To whom correspondence should be addressed. Fax: 1-902-494-1310.
Tel: 1-902-494-7190. E-mail: mark.stradiotto@dal.ca.
† Department of Chemistry, Dalhousie University.
(2) For some prominent examples featuring alternative Ru complexes,
see: (a) Gunanathan, C.; Ben-David, Y.; Milstein, D. Science 2007, 317,
790. (b) Grubbs, R. H. Angew. Chem., Int. Ed. 2006, 45, 3760. (c) Chauvin,
Y. Angew. Chem., Int. Ed. 2006, 45, 3741. (d) Noyori, R. Angew. Chem.,
Int. Ed. 2002, 41, 2008.
(3) (a) Rankin, M. A.; Hesp, K. D.; Schatte, G.; McDonald, R.;
Stradiotto, M. Chem. Commun. 2008, 250. (b) Lundgren, R. J.; Rankin,
M. A.; McDonald, R.; Stradiotto, M. Organometallics 2008, 27, 254. (c)
Rankin, M. A.; MacLean, D. F.; Schatte, G.; McDonald, R.; Stradiotto, M.
J. Am. Chem. Soc. 2007, 129, 15855. (d) Rankin, M. A.; Schatte, G.;
McDonald, R.; Stradiotto, M. J. Am. Chem. Soc. 2007, 129, 6390. (e)
Lundgren, R. J.; Rankin, M. A.; McDonald, R.; Schatte, G.; Stradiotto, M.
Angew. Chem., Int. Ed. 2007, 46, 4732. (f) Rankin, M. A.; McDonald, R.;
Ferguson, M. J.; Stradiotto, M. Organometallics 2005, 24, 4981. (g) Rankin,
M. A.; McDonald, R.; Ferguson, M. J.; Stradiotto, M. Angew. Chem., Int.
Ed. 2005, 44, 3603.
‡ University of Alberta.
§ Atlantic Region Magnetic Resonance Center, Dalhousie University.
(1) For selected recent reports and reviews, see: (a) Ito, M.; Ikariya, T.
Chem. Commun. 2007, 5134. (b) Ito, M.; Sakaguchi, A.; Kobayashi, C.;
Ikariya, T. J. Am. Chem. Soc. 2007, 129, 290. (c) Palacios, M. D.; Puerta,
M. C.; Valerga, P.; Lledo´s, A.; Veilly, E. Inorg. Chem. 2007, 46, 6958. (d)
Ikariya, T.; Murata, K.; Noyori, R. Org. Biomol. Chem. 2006, 4, 393. (e)
Bruneau, C.; Renaud, J.-L.; Demerseman, B. Chem.-Eur. J. 2006, 12, 5178.
(f) Trost, B. M.; Frederiksen, M. U.; Rudd, M. T. Angew. Chem., Int. Ed.
2005, 44, 6630. (g) Jime´nez-Tenorio, M.; Puerta, M. C.; Valerga, P. Eur.
J. Inorg. Chem. 2004, 17. (h) Nagashima, H.; Kondo, H.; Hayashida, T.;
Yamaguchi, Y.; Gondo, M.; Masuda, S.; Miyazaki, K.; Matsubara, K.;
Kirchner, K. Coord. Chem. ReV. 2003, 245, 177. (i) Glaser, P. B.; Tilley,
T. D. J. Am. Chem. Soc. 2003, 125, 13640. (j) Davies, S. G.; McNally,
J. P.; Smallridge, A. J. AdV. Inorg. Chem. 1990, 30, 1.
10.1021/om800761c CCC: $40.75
2009 American Chemical Society
Publication on Web 12/15/2008

Ruthenium Carbene ReactiVity
Organometallics, Vol. 28, No. 1, 2009 75
Scheme 1. Interconversion of 1 and 2 via Reversible
r-Hydride Elimination
nonrigid 18-electron complex 1. Herein we report on the results
of these investigations, including studies documenting the
reactivity of 1 with L-donor (L ) CO, PR3) and E-H (E ) B,
Si, P) containing substrates.
Figure 1. ORTEP diagram for 2 · PMe3, shown with 50% displace-
ment ellipsoids and with the atomic numbering scheme depicted;
selected H-atoms have been omitted for clarity.
Results and Discussion
Scheme 2. Reactions Involving 1 and CO, PMe3, and PH2Ph
Selective Inversion NMR Experiments. Well-documented
reversible R-hydride elimination phenomena involving alkyl-
metal species are rare in comparison to analogous ꢀ-hydride
elimination reactions,4,5 and to the best of our knowledge the
interconversion of 1 and 2 represents the only spectroscopically
characterized reversible R-hydride elimination process involving
ruthenium. Expanding on our previous qualitative examination
of this chemical exchange process by use of 1D- and 2D-EXSY
1H NMR experiments,3f,g we turned our attention to obtaining
quantitative rate data. The rate constant for exchange of the
Ru(H)dCH and Ru(H)dCH environments in 1 (59 ( 1 s-1
,
1
(2.118(2) Å) and RuC-N (1.477(2) Å) distances in 2 · PMe3
are lengthened significantly relative to those found in 1 (1.886(2)
and 1.374(3) Å),3f,g thereby supporting the description of
2 · PMe3 as being a base-stabilized adduct of the purported
alkylruthenium intermediate, 2. The planarity at nitrogen
300 K) was measured by use of selective inversion H NMR
techniques, employing the program CIFIT for data analysis.6
This rate can be compared with R-hydride elimination rates
reported by Schrock and co-workers5b for molybdenum com-
plexes (102-103 s-1, ca. 295 K), as well as Threlkel and
Bercaw5c for a niobium complex (15.7 s-1, 305 K).
(∑angles
) 358.5°) and the contracted N-C2 distance
at
N
(1.347(2) Å) in 2 · PMe3 are indicative of π-conjugation
involving the nitrogen lone pair and the adjacent indene
fragment. The apparent reactivity of 2 with CO differs from
that of a related cyclometalated LnRu(H)dCHR complex
reported by Caulton and co-workers,7 for which uptake of 2
equiv of CO is observed to give the corresponding Ln(CO)Ru-
(CO)-CH2R complex. Efforts to prepare related 2 · L adducts
by using PPh3, 4-dimethylaminopyridine, PhCN, MeCN, PhNH2,
acetone, or benzophenone at ambient temperature resulted in
the incomplete consumption of 1 (31P NMR), while heating of
these reaction mixtures (60 °C) led to decomposition.
Reactions with L-Donor Substrates. Exposure of 1 to either
an atmosphere of CO or an equivalent of PMe3 resulted in the
quantitative (31P NMR) conversion to 2 · CO or 2 · PMe3 in 98%
and 93% isolated yield, respectively (Scheme 2). Solution NMR
data fully support the structural formulation provided for these
complexes, and in the case of 2 · PMe3, the connectivity was
confirmed on the basis of data obtained from a single-crystal
X-ray diffraction study. An ORTEP diagram of 2 · PMe3 is
presented in Figure 1, while crystallographic data and selected
interatomic distances for each of the crystallographically
characterized compounds reported herein are collected in Tables
1 and 2, respectively. In keeping with 2 · PHPh2, the Ru-CN
Given the apparent propensity of 1 (and/or 2) for E-H bond
activation (Vide infra), we turned our attention to phosphine
substrates featuring P-H substituents. In an effort to probe
possible P-H bond activation processes in the previously
reported adduct 2 · PHPh2,3f,g we prepared 2 · PDPh2 and
periodically monitored the position of the isotopic label by use
of H and H NMR methods. However, after 96 h in benzene
or C6D6, no scrambling of the deuterium label was noted.
Furthermore, no P-H bond activation chemistry was observed
upon treatment of 1 with an equivalent of PH2Ph; quantitative
formation of 2 · PH2Ph was observed (31P NMR), and in turn
this complex was isolated as an analytically pure solid in 67%
yield (Scheme 2).
(4) For recent discussions of M-alkyl/M-alkylidene and related equilibria
in late metal chemistry, see: (a) Alvarez, E.; Paneque, M.; Petronilho, A. G.;
´
Poveda, M. L.; Santos, L. L.; Carmona, E.; Mereiter, K. Organometallics
2007, 26, 1231. (b) Kuznetsov, V. F.; Abdur-Rashid, K.; Lough, A. J.;
Gusev, D. G. J. Am. Chem. Soc. 2006, 128, 14388. (c) Salem, H.; Ben-
David, Y.; Shimon, L. J. W.; Milstein, D. Organometallics 2006, 25, 2292.
(d) Clot, E.; Chen, J.; Lee, D.-H.; Sung, S. Y.; Appelhans, L. N.; Faller,
J. W.; Crabtree, R. H.; Eisenstein, O. J. Am. Chem. Soc. 2004, 126, 8795.
(e) Carmona, E.; Paneque, M.; Poveda, M. L. Dalton Trans. 2003, 4022.
(f) Caulton, K. G. J. Organomet. Chem. 2001, 617-618, 56.
(5) Reports providing quantitative rate data for reversible R-hydride
elimination processes are scarce: (a) Morton, L. A.; Wang, R.; Yu, X.;
Campana, C. F.; Guzei, I. A.; Yap, G. P. A.; Xue, Z.-L. Organometallics
2006, 25, 427. (b) Schrock, R. R.; Seidel, S. W.; Mo¨sch-Zanetti, N. C.;
Shih, K.-Y.; O’Donoghue, M. B.; Davis, W. M.; Reiff, W. M. J. Am. Chem.
Soc. 1997, 119, 11876. (c) Threlkel, R. S.; Bercaw, J. E. J. Am. Chem.
Soc. 1981, 103, 2650.
1
2
(6) (a) Bain, A. D. Prog. Nucl. Magn. Reson. 2003, 43, 63. (b) Bain,
A. D.; Cramer, J. A. J. Magn. Res. A 1996, 118, 21. (c) Bain, A. D.; Cramer,
J. A. J. Magn. Reson. A 1993, 103, 217. (d) Bain, A. D.; Cramer, J. A. J.
Phys. Chem. 1993, 97, 2884.
(7) Ingleson, M. J.; Yang, X.; Pink, M.; Caulton, K. G. J. Am. Chem.
Soc. 2005, 127, 10846.

76 Organometallics, Vol. 28, No. 1, 2009
Rankin et al.
Table 1. Crystallographic Data for 2 · PMe3, 3a, 3b, 3d, 5, and 6
2 · PMe3
3a
3b
3d
5
6
empirical formula
fw
C30H49N1P2Ru1
586.71
C39H52N1P1Si1Ru1
694.95
C33H48N1P1Si1Ru1
617.85
C33H47Cl1N1P1Si1Ru1 C33H43B1N1O2P1Ru1 C36H53B1N1P1Ru1
653.30 628.53 642.64
cryst dimens
cryst syst
space group
a (Å)
b (Å)
c (Å)
R (deg)
ꢀ (deg)
γ (deg)
V (Å3)
0.62 × 0.57 × 0.40 0.32 × 0.22 × 0.03 0.35 × 0.33 × 0.13 0.38 × 0.28 × 0.28 0.53 × 0.16 × 0.15 0.52 × 0.39 × 0.08
monoclinic
P21/c
monoclinic
P21/n
triclinic
monoclinic
P21/c
triclinic
monoclinic
P21/n
j
j
P1
P1
14.8499(10)
10.6117(7)
19.3093(13)
90
106.1644(8)
90
10.4510(17)
32.927(4)
11.0385(16)
90
114.777(10)
90
9.1971(12)
9.4967(13)
18.536(3)
85.730(2)
80.573(2)
76.799(2)
1553.7(4)
2
9.2240(13)
9.8579(14)
35.255(5)
90
95.641(2)
90
8.7547(8)
10.0788(9)
19.0325(16)
80.9990(11)
78.3360(11)
70.1735(11)
1540.1(2)
2
13.7723(9)
15.3271(11)
15.9948 (11)
90
97.8006(10)
90
2922.5(3)
4
3448.8(9)
4
3190.2(8)
4
3345.1(4)
4
Z
Fcalcd (g cm-3
)
1.333
1.338
1.323
1.360
1.355
1.276
µ (mm-1
)
0.665
0.564
0.616
0.685
0.591
0.541
range of transmn
2θ limit (deg)
0.7769-0.6834
54.98
0.9833-0.8402
50.00
0.9242-0.8132
52.84
0.8313-0.7807
54.88
0.9166-0.7449
55.04
0.9580-0.7662
54.94
-19 e h e 19
-13 e k e 13
-25 e l e 25
24934
-12 e h e 0
-39 e k e 0
-11 e l e 13
6366
-11 e h e 11
-11 e k e 11
-23 e l e 23
12356
-11 e h e 11
-12 e k e 12
-45 e l e 45
26737
-11 e h e 11
-13 e k e 13
-24 e l e 24
13302
-17 e h e 17
-19 e k e 19
-20 e l e 20
28881
total data collected
indep reflns
6703
6022
6350
7263
6931
7631
Rint
0.0140
0.0721
0.0346
0.0320
0.0183
0.0293
obsd reflns
6262
3623
5202
6773
6276
6530
data/restraints/params
goodness-of-fit
6703/0/313
1.083
0.0241
0.0657
0.729, -0.319
6022/0/399
1.020
0.0672
0.1407
0.518, -0.515
6350/0/353
1.068
0.0379
0.0919
0.978, -0.388
7263/1/353
1.395
0.0642
0.1499
1.553, -1.208
6931/0/358
1.072
0.0282
0.0732
0.696, -0.206
7631/0/377
1.066
0.0287
0.0746
0.616, -0.201
2
2
R1 [Fo g 2σ(Fo )]
2
2
wR2 [Fo g -3σ(Fo )]
largest peak, hole (e Å-3
)
Table 2. Selected Interatomic Distances (Å) and Angles (deg) for
Scheme 3. Reactions Involving 1 and Silanes
2 · PMe3, 3a, 3b, 3d, 5, and 6
a
3ab
3bb
3db d
5g
6g h
,
,
2 · PMe3
Ru-P
2.2842(4) 2.315(2) 2.3243(8) 2.339(1) 2.2427(5) 2.3172(5)
2.2806(4) 2.377(2) 2.3445(9) 2.332(1) 2.048(2)
Ru-X
Ru-H*
X-H
Ru-H* · · · X
Ru-CN
C-NMe
N-CH3
N-C2
1.51(6) 1.44(3)
1.46(6) 1.44(3)c
1.84(6) 1.89(3)
1.57(2)e
1.74(2)
1.09(2)
1.38(2)
2.10f
2.118(2) 2.141(7) 2.167(3) 2.158(5) 1.896(2)
1.477(2) 1.472(8) 1.454(4) 1.463(6) 1.371(2) 1.510(2)
1.460(2) 1.464(8) 1.458(4) 1.458(6) 1.470(2) 1.487(2)
1.347(2) 1.342(9) 1.339(4) 1.332(7) 1.380(2) 1.451(2)
1.806(2) 1.782(7) 1.804(3) 1.800(5) 1.820(2) 1.813(2)
P-C3
∑N-C angles 358.5
of 1 was observed in reactions employing Me2PhSiH at ambient
temperature, and attempts to conduct the reaction at higher
temperatures resulted in decomposition. However, upon treat-
ment with Ph2SiH2 or PhSiH3, compound 1 was transformed
cleanly into 3a or 3b (31P NMR), thereby allowing for the
isolation of these complexes as analytically pure solids in 92%
and 94% yield, respectively. For each of 3a and 3b, solution
NMR data supported their identity as compounds formally
arising from net Si-H addition across the RudC unit in 1, or
alternatively via Si-H oxidative addition to the reactive
359.3
359.7
359.5
359.8
328.5
a X ) P2. b X ) Si. c The second Si-H distance is 1.45(3). d Si-Cl
2.139(2). e Distance restrained during refinement. f Measured in the final
refined structure; Si-H added at calculated position. g X ) B. h Ru-N
2.226(2).
Reactions with Silanes. Encouraged by the rich reaction
chemistry exhibited by Cp′RuLn complexes with organosilanes,8
the reactivity of 1 with Si-H-containing substrates was
examined (Scheme 3). In preliminary experiments employing
Ph3SiH or Et3SiH, no reaction was observed at ambient
temperature, while heating of these reaction mixtures (60 °C)
resulted in decomposition. Similarly, only partial consumption
2
intermediate 2. The observed JSiH values in 3a (22.9 Hz) and
3b (7.8 Hz) point to an unsymmetrical Ru-H · · · Si interaction
in each of these complexes in solution.8a,e Such interactions were
also observed in the solid state; ORTEP diagrams for 3a and
3b are presented in Figures 2 and 3. The relevant interatomic
distances in each of these silane addition products compare well
with those of 2 · PMe3 (Vide supra), including the observation
of a Ru-CN distance that is in keeping with a bond order of
unity. Although we are hesitant to comment definitively with
regard to the position of hydride ligands bridging Ru and Si,
both 3a and 3b appear to feature Si centers that contain Si-H
fragments (1.46(6) Å in 3a; 1.44(3) and 1.45(3) Å in 3b) as
well as Ru-H · · · Si contacts (1.84(6) Å in 3a; 1.89(3) Å in 3b).
Despite the apparent existence of such Ru-H · · · Si interactions,
no chemical exchange was observed between the Ru-H and
the Si-H environments within 3a or 3b on the basis of EXSY
1H NMR experiments.9
(8) For selected reports and reviews, see: (a) Lachaize, S.; Sabo-Etienne,
S. Eur. J. Inorg. Chem. 2006, 2115. (b) Osipov, A. L.; Vyboishchikov,
S. F.; Dorogov, K. Y.; Kuzmina, L. G.; Howard, J. A. K.; Lemenovskii,
D. A.; Nikonov, G. I. Chem. Commun. 2005, 3349. (c) Osipov, A. L.;
Gerdov, S. M.; Kuzmina, L. G.; Howard, J. A. K.; Nikonov, G. I.
Organometallics 2005, 24, 587. (d) Takao, T.; Amako, M.; Suzuki, H.
Organometallics 2001, 20, 3406. (e) Corey, J. Y.; Braddock-Wilking, J.
Chem. ReV. 1999, 99, 175. (f) Shelby, Q. D.; Lin, W.; Girolami, G. S.
Organometallics 1999, 18, 1904. (g) Lemke, F. R.; Galat, K. J.; Youngs,
W. J. Organometallics 1999, 18, 1419. (h) Tobita, H.; Kurita, H.; Ogino,
H. Organometallics 1998, 17, 2850. (i) Wada, H.; Tobita, H.; Ogino, H.
Organometallics 1997, 16, 3870. (j) Mitchell, G. P.; Tilley, T. D. J. Am.
Chem. Soc. 1997, 119, 11236. (k) Campion, B. K.; Heyn, R. H.; Tilley,
T. D. Chem. Commun. 1992, 1201. (l) Campion, B. K.; Heyn, R. H.; Tilley,
T. D. Organometallics 1992, 11, 3918. (m) Straus, D. A.; Zhang, C.;
Quimbita, G. E.; Grumbine, S. D.; Heyn, R. H.; Tilley, T. D.; Rheingold,
A. L.; Geib, S. J. J. Am. Chem. Soc. 1990, 112, 2673. (n) Straus, D. A.;
Tilley, T. D.; Rheingold, A. L.; Geib, S. J. J. Am. Chem. Soc. 1987, 109,
5872. (o) References 1i and 3a,c,d herein.
The chlorosilanes Ph2SiClH and PhSiClH2 were also observed
to react cleanly upon addition to 1, affording the corresponding

Ruthenium Carbene ReactiVity
Organometallics, Vol. 28, No. 1, 2009 77
Scheme 4. Reaction Involving 1 and Ph2SiD2
Scheme 5. Reaction Involving 1 and H(OEt2)2B(C6F5)4 (HX)
Figure 2. ORTEP diagram for 3a, shown with 50% displacement
ellipsoids and with the atomic numbering scheme depicted; selected
H-atoms have been omitted for clarity.
With an interest in probing the mechanistic pathway leading
to the formation of 3a, compound 1 in benzene or C6D6 was
treated with 1 equiv of Ph2SiD2, and the progress of the reaction
was monitored by use of NMR techniques (Scheme 4). While
31P NMR data confirmed the clean formation of the anticipated
addition product within 2 h, data obtained from 1H and 2H NMR
experiments provided evidence for deuteration exclusively at
the Si-H and the RuC-H positions, as in 3a-d2.10 These
observations are inconsistent with simple Si-H oxidative
addition to the reactive intermediate 2 (in which deuteration at
Ru-H and Si-H would be anticipated in the first-formed
product, as in 3a′-d2), and are in keeping with net Si-H addition
across the RudC unit in 1. We cannot unequivocally discount
the possibility that 3a′-d2is the unobserved kinetic product in
this reaction, which in turn rearranges rapidly to 3a-d2 via
preferential C-D reductive elimination followed by C-H
oxidative addition. Nonetheless, the transformation of 1 into
3a appears to represent the first documented net addition of an
Si-H bond across a RudC linkage.11 Continued monitoring
of 3a-d2 by use of NMR methods over the course of two weeks
revealed partial deuterium incorporation at the NMe, Si-H,
RuC-H, and Ru-H positions. While the conversion of RudC
species into complexes featuring Ru-R and Ru-H linkages
has been observed under catalytic hydrogenation conditions,12
no reaction was observed upon exposure of 1 to an atmosphere
of H2 at ambient temperature. However, treatment of 1 with
Jutzi’s acid13 (H(OEt2)2B(C6F5)4) resulted in the quantitative
formation of the known compound 4 (the cyclometalated variant
of [Cp*Ru(κ2-2-NMe2-3-PiPr2-indene)]+B(C6F5)4-; Scheme 5).3f,g
Reactions with Boranes. There is considerable interest in
studying the stoichiometric reactivity of late metal complexes
Figure 3. ORTEP diagram for 3b, shown with 50% displacement
ellipsoids and with the atomic numbering scheme depicted; selected
H-atoms have been omitted for clarity.
Figure 4. ORTEP diagram for 3d, shown with 50% displacement
ellipsoids and with the atomic numbering scheme depicted; selected
H-atoms have been omitted for clarity.
Si-H addition products 3c and 3d (respectively) in 87% and
82% isolated yield (Scheme 3). Complex 3d forms as a mixture
of two diastereomers (ca. 80:20 on the basis of NMR data),
and single-crystal X-ray diffraction data obtained from a sample
of 3d allowed for the solid state characterization of one of
these diastereomers; an ORTEP diagram of 3d is presented in
Figure 4. The salient structural features of 3d compare well with
those of 3a and 3b (Ru-H · · · Si 2.10 Å in 3d), as well as those
found within related Cp*Ru chlorosilyl complexes.8b,c,k
(10) Compound 3a-d2 is formed as ca. 1:1 mixture of diasteromers.
1
Selected diagnostic NMR data for 3a-d2 in benzene: H NMR: δ 3.78 (d,
J ) 6.0 Hz, Ru-C(H)(D)-N), 3.19 (d, J ) 3.0 Hz, Ru-C(D)(H)-N), 2.39
(NMe), 2.38 (NMe),-11.49 (d, 2JPH ) 29.0 Hz, Ru-H),-11.50 (d, 2JPH
)
2
28.5 Hz, Ru-H). H NMR: δ 5.31 (br, Si-D), 3.77 (br, Ru-C(D)), 3.17
(br, Ru-C(D)). 13C{1H} NMR: δ 46.4 (NMe), 46.3 (NMe). 31P{1H} NMR:
δ 47.9, 47.8.
(11) The addition of Si-H across RudC may represent an elementary
reaction step in hydrosilylation chemistry employing RudC precatalysts: (a)
Menozzi, C.; Dalko, P. I.; Cossy, J. J. Org. Chem. 2005, 70, 10717. (b)
Maifeld, S. V.; Tran, M. N.; Lee, D. Tetrahedron Lett. 2005, 46, 105. (c)
Arico´, C. S.; Cox, L. R. Org. Biomol. Chem. 2004, 2, 2558.
(12) (a) Schmidt, B. Eur. J. Org. Chem. 2004, 1865. (b) Louie, J.;
Bielawski, C. W.; Grubbs, R. H. J. Am. Chem. Soc. 2001, 123, 11312.
(13) Jutzi, P.; Mu¨ller, C.; Stammler, A.; Stammler, H.-G. Organome-
tallics 2000, 19, 1442.
(9) Chemical exchange of Ru-H and the Si-H environments in
LnRu(H)(SiHPh2) species has been observed previously: Gusev, D. G.;
Nadasdi, T. T.; Caulton, K. G. Inorg. Chem. 1996, 35, 6772.

78 Organometallics, Vol. 28, No. 1, 2009
Rankin et al.
with B-H-containing substrates, both in terms of the develop-
ment of metal-ligand bonding concepts and as a means of
advancing our mechanistic understanding of prominent catalytic
transformations such as the hydroboration of unsaturated
substrates and the dehydrogenative borylation of hydrocarbons.14,15
Treatment of 1 with ca. 2.4 equiv of catecholborane (HBcat) in
benzene at ambient temperature resulted in the consumption of
the starting complex after 0.5 h, along with the initial formation
of one major phosphorus-containing product (δ 31P ) 54.8, 5i;
ca. 85% of the reaction mixture) and three minor phosphorus-
containing products (δ 31P ) 72.2, 71.8 (5), and 70.9; totaling
ca. 15% of the reaction mixture). Carrying out analogous
reactions in C6D6 allowed for the further in situ NMR
characterization of 5i; 1H and 13C NMR studies confirmed that
this Ru-H species (δ 1H ) -12.05, 2JPH ) 23.5 Hz) does not
feature a RudCH linkage as in 1, and both the 1H and 11B NMR
(δ 11B ) 21.3) spectra of 5i were not significantly altered when
decoupled from the other nucleus. On the basis of these and
other NMR spectroscopic data, we tentatively assign 5i as a
Ru-boryl addition product (Scheme 6) that is structurally
analogous to the Ru-silyl species 3a-d. While continued
monitoring (11B and 31P NMR) over the course of 6 days
revealed the slow conversion of 5i to 5, the reappearance of 1
was also noted (5i:5:1 of ca. 5:30:2). As such, an additional
0.6 equiv of HBcat was added to the reaction mixture, which
promoted the quantitative conversion to 5 after a total reaction
time of 16 days; compound 5 was isolated as an analytically
pure powder in 54% yield. Efforts to accelerate the conversion
of 5i to 5 by heating such reaction mixtures at 60 °C resulted
in formation of a complex mixture of phosphorus-containing
Figure 5. ORTEP diagram for 5, shown with 50% displacement
ellipsoids and with the atomic numbering scheme depicted; selected
H-atoms have been omitted for clarity.
Scheme 6. Reaction Involving
(HBcat)
1 and Catecholborane
1
products. H and 13C NMR data confirmed the absence of a
Ru-H fragment and the existence of a RudCH linkage in 5,
thereby supporting the structural formulation presented in
Scheme 6. The connectivity in 5 was further confirmed by use
of X-ray diffraction techniques; an ORTEP diagram of 5 is
presented in Figure 5. Notably, the Ru-B distance in 5 (2.048(2)
Å) is shorter than related distances observed in the only other
crystallographically characterized Ru-Bcat complexes, Ru(Bcat)2-
(PPh3)2(CO)2 (2.100(3) and 2.095(4) Å) and Ru(Bcat)2-
(PPh3)2(CO)(CN-p-tolyl) (2.093(3) and 2.086(3) Å).16 In keeping
with the structural features of the parent carbeneruthenium
complex 1 (Vide supra),3f,g the planarity at nitrogen (∑angles at N
) 359.8°) and the relatively short Ru-C27 (RudC, 1.896(2)
Å), N-C27 (RuC-N, 1.371(2) Å; cf. N-CH3, 1.470(2) Å), and
N-C2 (1.380(2) Å) distances in 5 point to significant π-bonding
interactions along the Ru-C-N fragment and extending through
to the carbocyclic backbone of the indene ligand. In the absence
of additional data we are not able to comment definitively as to
whether 5i arises from B-H addition to 1 or 2, nor are we able
to provide mechanistic insights regarding the apparent dehy-
drogenation of 5i to give 5. However, the requirement of excess
HBcat to promote the formation of 5, along with the observation
that 1 is initially consumed and then is re-formed during the
course of this reaction, points to a potentially complex reaction
scenario involving the net metathesis of Ru-B/H, B-H, and
H-H bonds.14g By comparison, compound 1 was not observed
to react with pinacolborane (HBpin) under similar conditions
at ambient temperature, and heating of such reaction mixtures
at 60 °C for 7 days led to decomposition (31P NMR).
(14) (a) Braunschweig, H.; Kollann, C.; Rais, D. Angew. Chem., Int.
Ed. 2006, 45, 5254. (b) Aldridge, S.; Coombs, D. L. Coord. Chem. ReV.
2004, 248, 535. (c) Crudden, C. M.; Edwards, D. Eur. J. Org. Chem. 2003,
4695. (d) Braunschweig, H.; Colling, M. Coord. Chem. ReV. 2001, 223, 1.
(e) Piers, W. E. Angew. Chem., Int. Ed. 2000, 39, 1923. (f) Braunschweig,
H. Angew. Chem., Int. Ed. 1998, 37, 1786. (g) Irvine, G. J.; Lesley, M. J. G.;
Marder, T. B.; Norman, N. C.; Rice, C. R.; Robins, E. G.; Roper, W. R.;
Whittell, G. R.; Wright, L. J. Chem. ReV. 1998, 98, 2685. (h) Beletskaya,
I.; Pelter, A. Tetrahedron 1997, 53, 4957.
(15) For selected reports pertaining to Cp′RuLn complexes, see: (a) Hesp,
K. D.; Rankin, M. A.; McDonald, R.; Stradiotto, M. Inorg. Chem. 2008,
47, 7471. (b) Kawano, Y.; Hashiva, M.; Shimoi, M. Organometallics 2006,
25, 4420. (c) Saito, T.; Kuwata, S.; Ikariya, T. Chem. Lett. 2006, 35, 1224.
(d) Kuan, S. L.; Leong, W. K.; Goh, L. Y.; Webster, R. D. J. Organomet.
Chem. 2006, 691, 907. (e) Murphy, J. M.; Lawrence, J. D.; Kawamura, K.;
Incarvito, C.; Hartwig, J. F. J. Am. Chem. Soc. 2006, 128, 13684. (f) Kuan,
S. L.; Leong, W. K.; Goh, L. Y.; Webster, R. D. Organometallics 2005,
24, 4639. (g) Merle, N.; Frost, C. G.; Koicok-Ko¨hn, G.; Willis, M. C.;
Weller, A. S. J. Organomet. Chem. 2005, 690, 2829. (h) Merle, N.; Koicok-
Ko¨hn, G.; Mahon, M. F.; Frost, C. G.; Ruggerio, G. D.; Weller, A. S.;
Willis, M. C. Dalton Trans. 2004, 3883. (i) Waltz, K. M.; Hartwig, J. F.
J. Am. Chem. Soc. 2000, 122, 11358. (j) Hartwig, J. F.; Bhandari, S.; Rablen,
P. R. J. Am. Chem. Soc. 1994, 116, 1839.
Addition of 1 equiv of mesitylborane (MesBH2) to a solution
of 1 in benzene resulted in the quantitative conversion (31P
NMR) to a new phosphorus-containing product (6) over the
course of 0.5 h (Scheme 7). Compound 6 was isolated in 81%
yield and characterized initially by use of NMR techniques; 1H
NMR and 13C NMR data confirmed the presence of Ru-H (δ
1H ) -11.27), N-CH2, and BMes fragments in 6, in the
absence of resonances attributable to a RudC(H) fragment.
While these preliminary spectroscopic observations point to the
possible identity of this complex as being a B-H addition
product analogous to 5i (i.e., 6i), the crystallographic charac-
(16) Rickard, C. E. F.; Roper, W. R.; Williamson, A.; Wright, L. J.
Organometallics 2000, 19, 4344.

Ruthenium Carbene ReactiVity
Organometallics, Vol. 28, No. 1, 2009 79
substrates were documented. Exposure of 1 to an atmosphere
of CO or to an equivalent of either PMe3 or PH2Ph afforded
the corresponding 2 · L adduct, thereby providing what can be
viewed as indirect support for the ability of 1 to serve as a
masked source of the unobserved alkylruthenium complex 2.
However, we cannot rule out reaction mechanisms leading to
2 · L involving L-addition to alternative, coordinatively unsatur-
ated reactive intermediates derived from 1, including those
generated via Ru-P dissociation. In examining the reactivity
of 1 with Si-H-containing substrates, products of net Si-H
addition were observed. While such addition products could in
principle arise via addition to either 1 or 2, a deuterium labeling
study employing Ph2SiD2 provided evidence in support of a
reaction mechanism involving previously undocumented Si-D
addition across the RudC unit in 1. Interesting and divergent
reactivity was noted with B-H-containing substrates. Complex
1 was observed to react with catecholborane (HBcat) to give a
first-formed B-H addition product that underwent net dehy-
drogenation to give an isolable (Bcat)RudC species. In contrast,
no intermediates were observed in the reaction of 1 with
mesitylborane (MesBH2); the product of this B-C bond forming
reaction corresponds to a Cp*Ru(P,N) complex featuring a
Ru-H-B bridge to a tethered borane fragment. Although
further mechanistic studies are required in order to comment
definitively regarding the possible intermediacy of 2 in the
observed reactivity of 1, the studies documented herein serve
to underscore the potentially interesting reaction chemistry that
may be derived from late metal complexes that exhibit reversible
R-hydride elimination.
Figure 6. ORTEP diagram for 6, shown with 50% displacement
ellipsoids and with the atomic numbering scheme depicted; selected
H-atoms have been omitted for clarity.
Scheme 7. A Possible Mechanistic Pathway in the Reaction
Involving 1 and Mesitylborane (MesBH2)
Experimental Section
General Considerations. 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 an mBraun
glovebox apparatus, utilizing glassware that was oven-dried (130
°C) and evacuated while hot prior to use. Celite (Aldrich) was oven-
dried for 5 days and then evacuated for 24 h prior to use. The
nondeuterated solvents diethyl ether, benzene, 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. Diethyl ether 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. All solvents used within the glovebox were
stored over activated 4 Å molecular sieves. Purification of MeCN
was achieved by refluxing over CaH2 for 4 days under dinitrogen,
followed by distillation. All deuterated solvents (Cambridge
Isotopes) and liquid silane reagents (Aldrich and Strem) were
degassed by using three repeated freeze-pump-thaw cycles and
then dried over 4 Å molecular sieves for 24 h prior to use. PH2Ph
(Aldrich) was stored over 4 Å molecular sieves for 24 h prior to
use. Pinacolborane (HBpin; Aldrich) was degassed by using three
repeated freeze-pump-thaw cycles prior to use. Compound 1
(unpublished FTIR (NaCl) data for 1: ν(Ru-H): 1937 cm-1),3f,g
terization of 6 allowed for the definitive characterization of this
complex as the 18-electron species depicted in Scheme 7. An
ORTEP diagram of 6 is presented in Figure 6. Compound 6 is
comprised of a Cp*RuH fragment supported by an unusual κ2-
P,N ligand featuring a tethered borane fragment that forms a
Ru-H-B bridge.17 While the formation of 6 can be viewed as
arising from initial B-H addition to either 1 or 2 to give the
unobserved intermediate 6i, which in turn could rearrange to 6
via B-C reductive elimination (by analogy with 5i and 5),
alternative Ru-C/H-B σ-bond metathesis reaction sequences
involving the putative alkylruthenium complex 2 cannot be ruled
out.
Summary and Conclusions
The rate of R-hydride elimination in 1 and the reactivity
properties of this stereochemically nonrigid 18-electron complex
with L-donor (L ) CO, PR3) and E-H (E ) B, Si, P) containing
18
H(OEt2)2B(C6F5)4,13 and MesBH2 were prepared employing
literature procedures. Hydrogen (99.999%, UHP grade) and carbon
monoxide gases (99.5%, chemically pure grade) were obtained from
Air Liquide and were used as received. All purchased and prepared
solid reagents were dried in Vacuo for 24 h prior to use. Otherwise,
all other commercial reagents were obtained from Aldrich and were
used as received. Unless otherwise stated NMR characterization
(17) For some other crystallographically characterized complexes featur-
ing a Ru-H-B bridging motif, see: (a) Alcaraz, G.; Clot, E.; Helmstedt,
U.; Vendier, L.; Sabo-Etienne, S. J. Am. Chem. Soc. 2007, 129, 8704. (b)
Lachaize, S.; Essalah, K.; Montiel-Palma, V.; Vendier, L.; Chaudret, B.;
Barthelat, J.-C.; Sabo-Etienne, S. Organometallics 2005, 24, 2935. (c)
Montiel-Palma, V.; Lumbierres, M.; Donnadieu, B.; Sabo-Etienne, S.;
Chaudret, B. J. Am. Chem. Soc. 2002, 124, 5624. (d) Baker, R. T.; Calabrese,
J. C.; Westcott, S. A.; Marder, T. B. J. Am. Chem. Soc. 1995, 117, 8777.
(e) References 15a-d and 15f-h herein.
(18) (a) Smith, K.; Pelter, A.; Jin, Z. Angew. Chem., Int. Ed. 1994, 33,
851. (b) Pelter, A.; Smith, K.; Buss, D.; Jin, Z. Heteroat. Chem. 1992, 3,
275.

80 Organometallics, Vol. 28, No. 1, 2009
Rankin et al.
data were collected at 300 K on a Bruker AV-500 spectrometer
operating at 500.1 (1H), 125.8 (13C), 99.4 (29Si), 160.5 (11B), and
202.5 (31P) MHz with chemical shifts reported in parts per million
C30H49P2NRu: C 61.39; H 8.42; N 2.39. Found: C 61.13; H 8.52;
N 2.34. 1H NMR (C6D6): δ 7.23 (d, 3JHH ) 8.0 Hz, 1H, C4-H or
3
C7-H), 7.26 (t, JHH ) 7.0 Hz, 1H, C5-H or C6-H), 7.14 (m,
1
downfield of SiMe4 (for H, 13C, and 29Si), 85% H3PO4 in water
3
1H, C7-H or C4-H), 6.92 (t, JHH ) 7.0 Hz, 1H, C6-H or
1
(for 31P), or BF3 · OEt2 (for 11B). H, 11B, and 13C NMR chemical
C5-H), 3.90 (m, 1H, N-C(Ha)(Hb)-Ru), 3.10 (m, 1H, P(CH-
MeaMeb)), 3.13-2.99 (m, 3H, N-C(Ha)(Hb)-Ru and C(Ha)(Hb)), 2.83
(s, 3H, NMe), 2.14 (m, 1H, P(CHMecMed)), 1.62 (s, 15 H, C5Me5),
shift assignments are given on the basis of data obtained from 13C-
DEPT, 1H-1H COSY, 1H-13C HSQC, 1H-13C HMBC, and
1H-11B HSQC NMR experiments. 29Si NMR chemical shift
assignments and coupling constant data are given on the basis of
data obtained from 1H-29Si HMBC/HMQC (including J-HMBC19)
3
3
1.36 (d of d, JPH ) 10.0 Hz, JHH ) 7.0 Hz, 3H, P(CHMecMed)),
1.11 (d of d, 3JPH ) 16.5 Hz, 3JHH ) 6.5 Hz, 3H, P(CHMeaMeb)),
3
1.07-1.02 (m, 12H, PMe3 and P(CHMecMed)), 0.97 (d of d, JPH
1
1
and H-coupled H-29Si HMQC experiments. The rate constant
for reversible R-hydride elimination in 1 was measured in C6D6
according to the procedure of Bain.6a Both selective inversion and
3
) 14.5 Hz, JHH ) 7.0 Hz, 3H, P(CHMeaMeb)). 13C{1H} NMR
(C6D6): δ 167.6 (d, 2JPC ) 13.1 Hz, C2), 151.1 (C3a or C7a), 135.7
(d, JPC ) 6.8 Hz, C7a or C3a), 127.0 (C5 or C6), 122.3 (C4 or
C7), 119.0 (C7 or C4), 118.7 (C6 or C5), 91.1 (d, 1JPC ) 38.5 Hz,
C3), 90.4 (C5Me5), 45.9 (NMe), 44.0 (d of d, 2JPC ) 17.4 Hz, 2JPC
) 14.2 Hz, N-CH2-Ru), 41.5 (d, 3JPC ) 6.7 Hz, C1), 31.0 (d of d,
1
nonselective H NMR experiments were performed, using a total
of 20 different delays. For the selective experiment, the Ru(H)dCH
signal was inverted using a 1.5 ms Gaussian pulse; a relaxation
delay of 7 s was used for both experiments. Data were analyzed
by using the program CIFIT.6b-d IR data were collected on a Bruker
VECTOR 22 FT-IR instrument. Elemental analyses were performed
by Canadian Microanalytical Service Ltd., Delta, British Columbia.
Synthesis of 2 · CO. Within a glovebox, a 250 mL glass reaction
flask was charged with 1 (0.094 g, 0.18 mmol), benzene (5 mL),
and a magnetic stirbar. After the vessel was sealed with a PTFE
cap, the resulting bright orange 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
then introduced to the vessel. The bomb was then resealed after
0.25 h, and the solution was stirred magnetically for 48 h. After
this time period, the solution was brownish-yellow and 31P NMR
data collected on an aliquot of this reaction mixture indicated
quantitative conversion to 2 · CO. Upon removal of solvent and
other volatile materials in Vacuo, followed by trituration with
pentane (2 × 1.5 mL), 2 · CO was isolated as an analytically pure,
tan powder (0.097 g, 0.018 mmol, 98%). Anal. Calcd for
C28H40PNORu: C 62.41; H 7.49; N 2.60. Found: C 62.43; H 7.64;
N 2.46. 1H NMR (C6D6): δ 7.55 (d, 3JHH ) 8.0 Hz, 1H, C4-H or
1JPC ) 23.0 Hz, JPC ) 3.6 Hz, P(CHMecMed)), 24.9 (d, JPC
)
3
1
26.0 Hz, P(CHMeaMeb)), 22.5 (d, 1JPC ) 22.8 Hz, PMe3), 21.8 (d,
2JPC ) 7.2 Hz, P(CHMecMed)), 21.1 (d, JPC ) 3.9 Hz, P(CH-
2
2
MeaMeb)), 20.5 (P(CHMecMed)), 20.1 (d, JPC ) 9.9 Hz, P(CH-
MeaMeb)), 10.7 (C5Me5). 31P{1H} NMR (C6D6): δ 54.0 (d, JPP
)
2
2
38.5 Hz), 5.9 (d, JPP ) 38.5 Hz). A crystal of 2 · PMe3 suitable
for single-crystal X-ray diffraction studies was grown from an
undisturbed concentrated pentane solution over the course of 4 days
at ambient temperature.
Synthesis of 2 · PH2Ph. Phenylphosphine (0.022 mL, 0.20 mmol)
was added via Eppendorf micropipette to a glass vial containing a
magnetically stirred solution of 1 (0.10 g, 0.20 mmol) in benzene
(6 mL). The vial was sealed with a PTFE-lined cap and magnetic
stirring was initiated. Over the course of several minutes, the
reaction mixture evolved from bright orange to yellow. After 0.5 h,
31P NMR data collected on an aliquot of this crude reaction mixture
indicated the quantitative formation of 2 · PH2Ph. The benzene
solvent and other volatile materials were removed in Vacuo, yielding
an oily yellow solid. The residue was treated with pentane (2 × 2
mL), after which the yellow supernatant solution was carefully
removed via a Pasteur pipet, leaving a yellow solid. The pentane
solution was stored at -35 °C in order to induce precipitation. After
24 h, a microcrystalline yellow solid that had formed was isolated
by transferring the supernatant solution to a new glass vial; this
solution was concentrated in Vacuo in order to induce further
precipitation. After repeating this procedure, the isolated solids were
combined and dried in Vacuo, yielding 2 · PH2Ph as an analytically
pure, pale yellow powder (0.083 g, 0.13 mmol, 67%). Anal. Calcd
for C33H47P2NRu: C 63.83; H 7.64; N 2.26. Found: C 63.81; H
7.64; N 1.93. 1H NMR (C6D6): δ 7.60 (d, 3JHH ) 8.0 Hz, 1H, C4-H
or C7-H), 7.32-7.22 (m, 3H, 2 P-aryl Hs and aryl H), 7.15 (m,
1H, aryl H), 7.11-7.05 (m, 3H, P-aryl Hs), 6.97 (t, 3JHH ) 7.0 Hz,
3
C7-H), 7.27 (t, JHH ) 7.5 Hz, 1H, C5-H or C6-H), 7.12 (d,
3JHH ) 7.0 Hz, 1H, C7-H or C4-H), 6.99 (t, 3JHH ) 7.5 Hz, 1H,
C6-H or C5-H), 3.85 (m, 1H, N-C(Ha)(Hb)-Ru), 3.38-3.28 (m,
2H, P(CHMeaMeb) and N-C(Ha)(Hb)-Ru), 3.20-2.95 (m, 2H,
C(Ha)(Hb)), 2.78 (s, 3H, NMe), 2.00 (m, 1H, P(CHMecMed)), 1.70
(s, 15 H, C5Me5), 1.36 (d of d, 3JPH ) 11.5 Hz, 3JHH ) 7.0 Hz, 3H,
P(CHMecMed)), 1.10-0.98 (m, 9H, P(CHMeaMeb) and P(CHMec-
2
Med)). 13C{1H} NMR (C6D6): δ 209.0 (d, JPC ) 18.7 Hz, CO),
2
168.8 (d, JPC ) 12.8 Hz, C2), 149.8 (C3a or C7a), 136.2 (d, JPC
) 7.9 Hz, C7a or C3a), 126.8 (C5 or C6), 123.0 (C4 or C7), 119.5
1
(C6 or C5), 119.1 (C7 or C4), 95.1 (C5Me5), 89.9 (d, JPC ) 48.2
Hz, C3), 43.7 (NMe), 40.4 (d, 3JPC ) 6.9 Hz, C1), 39.3 (d, 2JPC
)
1
15.1 Hz, N-CH2-Ru), 27.8 (d, JPC ) 21.4 Hz, P(CHMecMed)),
2
1
2
1H, C5-H or C6-H), 5.56 (d of d,1JPH ) 312.6 Hz, JHH ) 5.5
24.5 (d, JPC ) 32.7 Hz, P(CHMeaMeb)), 21.3 (d, JPC ) 7.0 Hz,
Hz, 1H, P(Ha)(Hb)), 5.12 (d of d of d,1JPH ) 328.1 Hz, 3JPH ) 7.5
2
P(CHMecMed)), 20.1 (P(CHMecMed)), 19.3 (d, JPC ) 2.9 Hz,
P(CHMeaMeb)), 19.0 (d, JPC ) 6.7 Hz, P(CHMeaMeb)), 10.3
2
2
Hz, JHH ) 5.5 Hz, 1H, P(Ha)(Hb)), 3.82 (m, 1H, N-C(Ha)(Hb)-
(C5Me5). 31P{1H} NMR (C6D6): δ 55.3. FTIR (NaCl; cm-1) ν(CO):
1897.
Ru), 3.51 (m, 1H, P(CHMeaMeb)), 3.11 (m, 1H, N-C(Ha)(Hb)-Ru),
3.05-2.94 (m, 2H, C(Ha)(Hb)), 2.33 (s, 3H, NMe), 2.13 (m, 1H,
3
P(CHMecMed)), 1.66 (s, 15 H, C5Me5), 1.36 (d of d, JPH ) 10.0
Synthesis of 2 · PMe3. A solution of PMe3 (1.0 M in toluene,
0.10 mL, 0.10 mmol) was added via Eppendorf micropipette to a
glass vial containing a bright orange solution of 1 (0.052 g, 0.10
mmol) in benzene (4 mL). The vial was then sealed with a PTFE-
lined cap and stirred magnetically for 22 h. During this time period,
the solution lightened gradually in color to golden yellow. 31P NMR
data collected on an aliquot of this solution indicated quantitative
conversion to 2 · PMe3. The solvents and other volatile materials
were then removed in Vacuo, which left an oily yellow-orange
residue. After the solid was triturated with pentane (2 × 1.5 mL),
the residual solvent was removed in Vacuo, which left 2 · PMe3 as
a yellow powder (0.056 g, 0.095 mmol, 93%). Anal. Calcd for
3
Hz, JHH ) 7.0 Hz, 3H, P(CHMecMed)), 1.17-1.09 (m, 6H,
3
P(CHMeaMeb) and P(CHMecMed)), 0.99 (d of d, JPH ) 14.5 Hz,
3JHH ) 6.5 Hz, 3H, P(CHMeaMeb)). 13C{1H} NMR (C6D6): δ 167.7
2
(d, JPC ) 12.6 Hz, C2), 151.8 (C3a or C7a), 136.0 (d, JPC ) 7.0
1
3
Hz, C7a or C3a), 134.0 (d of d, JPC ) 35.0 Hz, JPC ) 3.1 Hz,
P-aryl C), 133.1 (d, JPC ) 8.7 Hz, 2 P-aryl CHs), 128.4 (P-aryl
CH), 128.3-128.0 (2 P-aryl CHs, obscured by C6D6), 127.0 (C5
or C6), 122.5 (aryl CH), 118.9 (C4 or C7), 118.8 (aryl CH), 90.0
1
(C5Me5), 88.4 (d, JPC ) 42.0 Hz, C3), 45.7 (NMe), 42.6 (d of d,
2
3
2JPC ) 17.1 Hz, JPC ) 13.8 Hz, N-CH2-Ru), 40.9 (d, JPC ) 6.9
1
3
Hz, C1), 29.5 (d of d, JPC ) 21.4 Hz, JPC ) 3.3 Hz, P(CHMec-
1
2
Med)), 26.7 (d, JPC ) 28.8 Hz, P(CHMeaMeb)), 21.2 (d, JPC
)
(19) Meissner, A.; Sørensen, O. W. Magn. Reson. Chem. 2001, 39, 49.
7.0 Hz, P(CHMecMed)), 20.4-20.2 (m, P(CHMeaMeb) and either

Ruthenium Carbene ReactiVity
Organometallics, Vol. 28, No. 1, 2009 81
P(CHMeaMeb) or P(CHMecMed)), 19.2 (2JPC ) 7.5 Hz, P(CHMec-
Med) or P(CHMeaMeb)), 10.4 (C5Me5). 31P{1H} NMR (C6D6): δ
54.6 (d, JPP ) 40.5 Hz), 8.9 (d, JPP ) 40.5 Hz).
11.7 Hz, C2), 149.9 (C3a or C7a), 143.7 (Si-aryl C), 136.2 (d, JPC
) 8.4 Hz, C7a or C3a), 136.1 (2 Si-aryl CHs), 127.7 (Si-aryl CH),
127.5 (2 Si-aryl CHs), 126.8 (C5 or C6), 122.9 (C4 or C7), 119.5
2
2
1
Synthesis of 3a. To a glass vial containing a solution of 1 (0.088
g, 0.17 mmol) in benzene (6 mL) was added Ph2SiH2 (0.032 mL,
0.17 mmol) via Eppendorf micropipette. The vial was then sealed
with a PTFE-lined cap and the solution mixed manually by
inversion several times. After 4 h, 31P NMR data collected on an
aliquot of this solution indicated the quantitative formation of 3a.
Within this time period, the color of the solution changed from
bright orange to yellow. The benzene solvent and other volatiles
were then removed in Vacuo, yielding an oily orange-yellow solid.
After the residue was triturated with pentane (1.5 mL) and the
pentane was removed in Vacuo, 3a was isolated as an analytically
pure, light yellow-orange powder (0.11 g, 0.16 mmol, 92%). Anal.
Calcd for C39H52PNSiRu: C 67.39; H 7.55; N 2.02. Found: C 67.52;
(C6 or C5), 118.7 (C7 or C4), 95.0 (C5Me5), 87.9 (d, JPC ) 47.4
Hz, C3), 48.0 (NMe), 40.2 (d, 3JPC ) 6.8 Hz, C1), 38.9 (d, 2JPC
)
16.0 Hz, N-CH2-Ru), 29.6 (d, 1JPC ) 21.5 Hz, P(CHMecMed)), 24.0
1
2
(d, JPC ) 36.1 Hz, P(CHMeaMeb)), 21.5 (d, JPC ) 7.5 Hz,
2
P(CHMecMed)), 20.6 (P(CHMecMed)), 19.7 (d, JPC ) 5.8 Hz,
P(CHMeaMeb)), 18.8 (P(CHMeaMeb)), 9.6 (C5Me5). 31P{1H} NMR
(C6D6): δ 51.2. 29Si{1H} NMR (C6D6): δ 8.7 (1H-29Si HMBC/
HMQC), 1JSiH ) 188.8 Hz, 170.6 Hz (1H-coupled 1H-29Si HMQC),
2JSiH ) 7.8 Hz (1H-coupled 1H-29Si HMQC). FTIR (NaCl; cm-1
)
ν(Ru-H, Si-H): 2070-1982 (overlapping). A crystal of 3b suitable
for single-crystal X-ray diffraction studies was grown from a
concentrated MeCN solution at ambient temperature.
Synthesis of 3c. A protocol analogous to that described for 3a
was used: a mixture of 1 (0.026 g, 0.051 mmol) and Ph2SiClH
(0.010 mL, 0.051 mmol) in benzene (3 mL) afforded 3c quantita-
tively within 12 h (31P NMR), which was isolated as an analytically
pure, pale yellow powder (0.032 g, 0.044 mmol, 87%). Anal. Calcd
for C39H51PNSiClRu: C 64.21; H 7.05; N 1.92. Found: C 64.39; H
1
H 7.49; N 1.93. H NMR (C6D6): δ 7.90-7.88 (m, 2H, Si-aryl
3
Hs), 7.64-7.62 (m, 2H, Si-aryl Hs), 7.36 (d, JHH ) 8.0 Hz, 1H,
C4-H or C7-H), 7.26-7.23 (m, 3H, 2 Si-aryl Hs and either C5-H
or C6-H), 7.15-7.11 (m, 2H, Si-aryl Hs), 7.03 (d, 3JHH ) 7.0 Hz,
1H, C7-H or C4-H), 6.94-6.90 (m, 3H, 2 Si-aryl Hs and either
C6-H or C5-H), 5.28 (d, J ) 1.5 Hz, 1H, Si-H), 3.80 (m, 1H,
N-C(Ha)(Hb)-Ru), 3.30 (m, 1H, P(CHMeaMeb)), 3.22 (d of d, J )
5.0 Hz, J ) 3.0 Hz, 1H, N-C(Ha)(Hb)-Ru), 2.66 (m, 1H, C(Ha)(Hb)),
2.39 (s, 3H, NMe), 2.22-2.16 (m, 2H, P(CHMecMed) and
C(Ha)(Hb)), 1.45-1.40 (m, 18H, C5Me5 and P(CHMeaMeb)), 1.26
1
7.17; N 1.55. H NMR (C6D6): δ 8.22-8.18 (m, 2H, Si-aryl Hs),
7.76-7.72 (m, 2H, Si-aryl Hs), 7.24-7.15 (m, 4H, 3 Si-aryl Hs
and either C4-H or C7-H), 7.06 (t, 3JHH ) 7.0 Hz, 1H, C5-H or
3
C6-H), 6.42 (d, JHH ) 7.0 Hz, 1H, C7-H or C4-H), 6.85 (t,
3JHH ) 7.0 Hz, 1H, C6-H or C5-H), 6.76-6.73 (m, 3H, Si-aryl
Hs), 4.00-3.97 (m, 2H, N-C(Ha)(Hb)-Ru), 3.27 (br m, 1H,
P(CHMeaMeb)), 2.89 (s, 3H, NMe), 2.49 (m, 1H, C(Ha)(Hb)), 2.14
(m, 1H, P(CHMecMed)), 1.75 (m, 1H, C(Ha)(Hb)), 1.47 (s, 15H,
3
3
(d of d, JPH ) 11.5 Hz, JHH ) 7.0 Hz, 3H, P(CHMecMed)), 1.20
3
3
(d of d, JPH ) 17.0 Hz, JHH ) 7.0 Hz, 3H, P(CHMeaMeb)), 0.89
(d of d, 3JPH ) 15.5 Hz,3JHH ) 7.0 Hz, 3H, P(CHMecMed)), -11.49
(d, JPH ) 28.7 Hz, 1H, Ru-H). 13C{1H} NMR (C6D6): δ 168.6
C5Me5), 1.41 (d of d, JPH ) 16.0 Hz, JHH ) 7.0 Hz, 3H,
P(CHMeaMeb)), 1.24-1.14 (m, 6H, P(CHMecMed) and P(CH-
2
3
3
(d, 2JPC ) 8.4 Hz, C2), 149.9 (C3a or C7a), 145.7 (Si-aryl C), 145.6
(Si-aryl C), 136.4 (2 Si-aryl CHs), 136.1 (d, JPC ) 8.7 Hz, C7a or
C3a), 135.3 (2 Si-aryl CHs), 128.2 (Si-aryl CH), 127.4 (Si-aryl
CH), 127.3 (Si-aryl CH), 126.8 (Si-aryl CH), 126.7 (C5 or C6),
126.6 (2 Si-aryl CHs), 122.5 (C4 or C7), 119.1 (C6 or C5), 118.2
(C7 or C4), 95.4 (C5Me5), 86.3 (d, 1JPC ) 52.0 Hz, C3), 46.4 (NMe),
3
3
MeaMeb)), 0.84 (d of d, JPH ) 15.0 Hz, JHH ) 7.0 Hz, 3H,
P(CHMecMed)), -11.58 (d, 2JPH ) 29.0 Hz, 1H, Ru-H). 13C{1H}
NMR (C6D6): δ 168.7 (d, 2JPC ) 11.9 Hz, C2), 149.1 (C3a or C7a),
147.8 (Si-aryl C), 145.6 (Si-aryl C), 136.3 (d, JPC ) 9.4 Hz, C7a
or C3a), 135.3 (2 Si-aryl CHs), 133.8 (2 Si-aryl CHs), 128.1 (C5
or C6, obscured by C6D6), 127.2 (2 Si-aryl CHs), 126.6 (Si-aryl
CH), 126.5 (Si-aryl CH), 125.9 (2 Si-aryl CHs), 122.4 (C4 or C7),
119.3 (C6 or C5), 117.7 (C7 or C4), 97.8 (C5Me5), 45.9 (NMe),
39.9 (d, 3JPC ) 7.5 Hz, C1), 38.2 (d, 2JPC ) 15.2 Hz, N-CH2-Ru),
40.4 (d, 3JPC ) 7.2 Hz, C1), 38.9 (d, JPC ) 15.3 Hz, N-CH2-Ru),
2
30.5 (d,1JPC ) 21.3 Hz, P(CHMecMed)), 25.3 (d, JPC ) 37.0 Hz,
1
2
P(CHMeaMeb)), 21.3 (d, JPC ) 7.4 Hz, P(CHMecMed)), 20.4
2
(P(CHMecMed)), 20.3 (P(CHMeaMeb)), 19.5 (d, JPC ) 5.7 Hz,
P(CHMeaMeb)), 9.5 (C5Me5). 31P{1H} NMR (C6D6): δ 47.7.
31.2 (d,1JPC ) 21.6 Hz, P(CHMecMed)), 25.7 (d, JPC ) 36.7 Hz,
1
29Si{1H} NMR (C6D6): δ 32.8 (1H-29Si HMBC/HMQC), JSiH
)
P(CHMeaMeb)), 22.1 (d, JPC ) 7.2 Hz, P(CHMecMed)), 21.5
1
2
178.5 Hz (1H-coupled 1H-29Si HMQC), JSiH ) 22.9 Hz (1H-
(P(CHMeaMeb) and P(CHMecMed)), 20.0 (d, JPC ) 5.3 Hz,
2
2
1
coupled H-29Si HMQC). FTIR (NaCl; cm-1) ν(Ru-H, Si-H):
P(CHMeaMeb)), 9.7 (C5Me5). 31P{1H} NMR (C6D6): δ 42.6.
29Si{1H} NMR (C6D6): δ 60.9 (1H-29Si HMBC), 2JSiH not detected
2066-1954 (overlapping). A crystal of 3a suitable for single-crystal
X-ray diffraction studies was grown from a concentrated Et2O
solution at -35 °C.
by J-HMBC nor 1H-coupled 1H-29Si HMQC. FTIR (NaCl; cm-1
ν(Ru-H): 1968.
)
Synthesis of 3b. A protocol analogous to that described for 3a
was used: a mixture of 1 (0.097 g, 0.19 mmol) and PhSiH3 (0.024
mL, 0.19 mmol) in benzene (5 mL) afforded 3b quantitatively
within 0.5 h (31P NMR), which was isolated as an analytically pure,
light yellow powder (0.11 g, 0.18 mmol, 94%). Anal. Calcd for
C33H48PNSiRu: C 64.05; H 7.82; N 2.26. Found: C 63.71; H 7.93;
Synthesis of 3d. A protocol analogous to that described for 3a
was used: a mixture of 1 (0.10 g, 0.20 mmol), PhSiClH2 (0.026
mL, 0.20 mmol), and benzene (6 mL) afforded 3d quantitatively
within 0.5 h (31P NMR), which was isolated as an analytically pure,
pale yellow powder (0.10 g, 0.16 mmol, 82%). Complex 3d forms
as a mixture of diastereomers (80:20) on the basis of NMR data.
Anal. Calcd for C33H47PNSiClRu: C 60.66; H 7.26; N 2.14. Found:
1
3
N 2.11. H NMR (C6D6): δ 8.06 (d, JHH ) 6.5 Hz, 2H, Si-aryl
Hs), 7.48 (d, 3JHH ) 8.0 Hz, 1H, C4-H or C7-H), 7.30 (t, 3JHH
)
C 60.43; H 7.30; N 2.14. Major diastereomer of 3d: H NMR
1
3
3
7.5 Hz, 2H, Si-aryl Hs), 7.25 (t, JHH ) 8.0 Hz, 1H, C5-H or
(C6D6): δ 8.29 (d, JHH ) 7.5 Hz, 2H, Si-aryl Hs), 7.36-7.31 (m,
C6-H), 7.21 (t, 3JHH ) 7.0 Hz, 1H, Si-aryl H), 7.12 (d, 3JHH ) 7.0
3H, 2 Si-aryl CHs and aryl H), 7.22-7.18 (m, 2H, Si-aryl CH and
3
3
Hz, 1H, C7-H or C4-H), 6.97 (t, JHH ) 7.0 Hz, 1H, C6-H or
aryl H), 7.10 (d, JHH ) 7.0 Hz, 1H, C4-H or C7-H), 6.94 (t,
C5-H), 4.44 (apparent t, J ) 5.0 Hz, 1H, Si(Ha)(Hb)), 4.23 (m,
1H, Si(Ha)(Hb)), 3.92 (apparent t, J ) 9.0 Hz, 1H, N-C(Ha)(Hb)-
Ru), 3.28 (m, 1H, P(CHMeaMeb)), 3.23-3.16 (m, 2H, C(Ha)(Hb)
and N-C(Ha)(Hb)-Ru), 3.03-2.98 (m, 4H, C(Ha)(Hb) and NMe),
2.12 (m, 1H, P(CHMecMed)), 1.43 (s, 15H, C5Me5), 1.35 (d of d,
3JHH ) 7.0 Hz, 1H, C5-H or C6-H), 5.51 (d, J ) 4.5 Hz, 1H,
Si-H), 4.06 (apparent t, J ) 10.0 Hz, 1H, N-C(Ha)(Hb)-Ru), 3.64
(d of d, J ) 9.0 Hz, J ) 4.0 Hz, N-C(Ha)(Hb)-Ru), 3.24-3.12 (m,
5H, NMe and C(Ha)(Hb) and P(CHMeaMeb)), 3.04 (m, 1H,
C(Ha)(Hb)), 2.07 (m, 1H, P(CHMecMed)), 1.51 (s, 15H, C5Me5),
3
3
3
3JPH ) 11.5 Hz, JHH ) 7.0 Hz, 3H, P(CHMecMed)), 1.17-1.08
1.28 (d of d, JPH ) 12.0 Hz, JHH ) 7.5 Hz, 3H, P(CHMecMed)),
3
3
(m, 6H, P(CHMeaMeb)), 0.99 (d of d, JPH ) 15.0 Hz, JHH ) 7.0
1.05 (d of d, 3JPH ) 17.0 Hz, 3JHH ) 7.0 Hz, 3H, P(CHMeaMeb)),
3
3
Hz, 3H, P(CHMecMed)), -11.72 (apparent d of t, J ) 30.3 Hz, J
0.96 (d of d, JPH ) 15.0 Hz, JHH ) 7.0 Hz, 3H, P(CHMecMed)),
3 3
) 4.5 Hz, 1H, Ru-H). 13C{1H} NMR (C6D6): δ 167.1 (d, JPC
)
0.77 (d of d, JPH ) 16.0 Hz, JHH ) 7.0 Hz, 3H, P(CHMeaMeb)),
2

82 Organometallics, Vol. 28, No. 1, 2009
Rankin et al.
3JPH ) 11.5 Hz, JHH ) 7.0 Hz, 3H, P(CHMecMed)), 1.14-1.06
-11.72 (d of d, J ) 31.5 Hz, J ) 4.0 Hz, 1H, Ru-H). 13C{1H}
NMR (C6D6): δ 168.0 (d, 2JPC ) 11.4 Hz, C2), 149.5 (C3a or C7a),
144.6 (Si-aryl C), 136.3 (d, JPC ) 8.8 Hz, C7a or C3a), 136.0 (2
Si-aryl CHs), 128.4 (Si-aryl CH), 127.3 (2 Si-aryl CHs), 126.8 (aryl
CH), 123.0 (C4 or C7), 119.6 (C6 or C5), 119.6 (aryl CH), 96.8
3
3
3
(m, 6H, P(CHMeaMeb)), 0.99 (d of d, JPH ) 15.0 Hz, JHH ) 7.0
Hz, 3H, P(CHMecMed)), -12.05 (d, 2JPH ) 23.5 Hz, 1H, Ru-H).
2
13C{1H} NMR (C6D6): δ 168.5 (d, JPC ) 12.5 Hz, C2), 151.2 (2
BO-aryl C), 150.2 (C3a or C7a), 136.3 (d, JPC ) 8.1 Hz, C7a or
C3a), 126.8 (C5 or C6), 122.8 (C4 or C7), 120.7 (2 BO-aryl CH),
119.4 (C7 or C4), 119.3 (C6 or C5), 110.2 (2 BO-aryl CH), 96.6
1
3
(C5Me5), 87.0 (d, JPC ) 49.7 Hz, C3), 46.6 (NMe), 40.2 (d, JPC
2
) 7.0 Hz, C1), 38.8 (d, JPC ) 16.0 Hz, N-CH2-Ru), 29.5 (d, 1JPC
1
1
3
) 22.1 Hz, P(CHMecMed)), 23.8 (d, JPC ) 36.9 Hz, P(CH-
(C5Me5), 88.6 (d, JPC ) 45.7 Hz, C3), 42.8 (NMe), 40.4 (d, JPC
2
2
MeaMeb)), 21.6 (d, JPC ) 7.5 Hz, P(CHMecMed)), 20.7 (P(CH-
) 6.5 Hz, C1), 37.3 (d, JPC ) 15.3 Hz, N-CH2-Ru), 28.1 (d, 1JPC
2
1
MecMed)), 19.4 (d, JPC ) 5.3 Hz, P(CHMeaMeb)), 18.0 (P(CH-
) 23.4 Hz, P(CHMecMed)), 23.1 (d, JPC ) 34.3 Hz, P(CH-
MeaMeb)), 9.6 (C5Me5). 31P{1H} NMR (C6D6): δ 47.0. 29Si{1H}
NMR (C6D6): δ 55.1 (1H-29Si HMBC/HMQC), 1JSiH ) 216.4 Hz
(1H-coupled 1H-29Si HMQC), 2JSiH ) 4.3 Hz (J-HMBC). Selected
NMR features for the minor diastereomer of 3d: 1H NMR (C6D6):
δ 5.80 (s, 1H, Si-H), 2.64 (s, 3H, NMe), 1.47 (s, 15H, C5Me5),
-10.97 (d, 2JPH ) 29.0 Hz, 1H, Ru-H). 13C{1H} NMR (C6D6): δ
MeaMeb)), 21.5 (d, JPC ) 7.5 Hz, P(CHMecMed)), 20.2 (P(CH-
2
2
MecMed)), 19.4 (d, JPC ) 6.4 Hz, P(CHMeaMeb)), 18.8 (P(CH-
MeaMeb)), 10.2 (C5Me5). 31P{1H} NMR (C6D6): δ 54.8. 11B{1H}
1
NMR (C6D6): δ 21.3 (br). NMR data for 5: H NMR (C6D6): δ
3
11.96 (d, J ) 2.5 Hz, 1H, RudCH), 7.54 (d, JHH ) 7.5 Hz, 1H,
3
C4-H or C7-H), 7.24 (d, JHH ) 7.0 Hz, 1H, C7-H or C4-H),
3
96.4 (C5Me5), 46.2 (NMe), 40.9 (d, JPC ) 7.0 Hz, C1), 37.7 (d,
7.19 (m, 1H, C5-H or C6-H), 7.09 (t, 3JHH ) 7.5 Hz, 1H, C6-H
or C5-H), 6.89 (apparent d of d, J ) 6.0 Hz, J ) 3.5 Hz, 2H,
BO-aryl Hs), 6.70 (apparent d of d, J ) 5.5 Hz, J ) 3.0 Hz, 2H,
BO-aryl Hs), 3.37-3.12 (m, 2H, C(Ha)(Hb)), 3.10 (s, 3H, NMe),
3.03 (m, 1H, P(CHMeaMeb)), 2.00 (s, 15H, C5Me5), 1.59 (m, 1H,
P(CHMecMed)), 1.11-1.01 (m, 6H, P(CHMeaMeb) and P(CHMec-
2JPC ) 15.3 Hz, N-CH2-Ru), 9.7 (C5Me5). 31P{1H} NMR (C6D6): δ
46.8. 29Si{1H} NMR (C6D6): δ 56.2 (1H-29Si HMBC/HMQC), 1JSiH
1
2
) 203.7 Hz (1H-coupled H-29Si HMQC), JSiH not detected by
J-HMBC. Slow evaporation of a concentrated pentane solution of
3d provided a crystal suitable for single-crystal X-ray diffraction
analysis, which was found to contain only one of the two
diastereomers. FTIR (NaCl; cm-1) ν(Ru-H, Si-H): 2090-1955
(overlapping).
3
3
Med)), 0.94 (d of d, JPH ) 16.0 Hz, JHH ) 7.5 Hz, 3H,
3
3
P(CHMecMed)), 0.66 (d of d, JPH ) 15.0 Hz, JHH ) 7.0 Hz, 3H,
P(CHMeaMeb)). 13C{1H} NMR (C6D6): δ 251.1 (d, JPC ) 16.2
2
2
Reaction of 1 with H(OEt2)2B(C6F5)4. Treatment of 1 (0.010
g, 0.020 mmol) in benzene (6 mL) with H(OEt2)2B(C6F5)4 (0.032
g, 0.039 mmol) resulted in the separation of a brown-yellow oil.
After the vial contents were stirred magnetically for a total of 10
min, the mixture was allowed to settle for 1 h. The clear benzene
supernatant was decanted away from the oil via pipet, and the oil
was dried in Vacuo and washed with pentane to give a pale yellow
solid. The solid was then treated with THF-d8, and NMR features
of this product were found to be consistent with the previously
characterized 4.3f,g
Hz, RudC), 159.9 (d, JPC ) 10.2 Hz, C2), 151.0 (2 BO-aryl C),
147.9 (C3a or C7a), 137.3 (d, JPC ) 6.8 Hz, C7a or C3a), 127.1
(C5 or C6), 123.1 (C4 or C7), 122.8 (C6 or C5), 121.8 (C7 or C4),
1
120.2 (2 BO-aryl CH), 110.1 (2 BO-aryl CH), 105.6 (d, JPC
)
3
39.8 Hz, C3), 98.7 (C5Me5), 48.9 (NMe), 41.0 (d, JPC ) 6.3 Hz,
C1), 33.6 (d, 1JPC ) 19.1 Hz, P(CHMecMed)), 24.8 (d, 1JPC ) 34.2
2
Hz, P(CHMeaMeb)), 19.7 (d, JPC ) 4.9 Hz, P(CHMecMed)), 19.5
(d, 2JPC ) 5.0 Hz, P(CHMecMed)), 18.5-18.3 (m, P(CHMeaMeb)),
11.3 (C5Me5). 31P{1H} NMR (C6D6): δ 71.8. 11B{1H} NMR (C6D6):
δ 53.2 (br). Slow evaporation of a concentrated pentane solution
of 5 provided a crystal suitable for single-crystal X-ray diffraction
analysis.
Formation of 5i and Synthesis of 5. To a glass vial containing
a magnetically stirred solution of 1 (0.084 g, 0.16 mmol) in benzene
(6 mL) was added catecholborane (0.040 mL, 0.38 mmol) via
Eppendorf micropipette, and the vial was then sealed with a PTFE-
lined cap. Analysis of 31P NMR collected on an aliquot of the
reaction mixture after 0.5 h revealed the complete consumption of
1, along with the formation of one major phosphorus-containing
product (δ 31P ) 54.8 (5i), ca. 85% of the reaction mixture) and
three minor phosphorus-containing products (δ 31P ) 72.2, 71.8
(5), and 70.9, totaling ca. 15% of the reaction mixture). A smaller
scale reaction conducted in C6D6 allowed for the in situ charac-
terization of 5i (data provided below). Continued monitoring of
the reaction mixture (31P NMR) over the course of 6 days revealed
the slow conversion of 5i to 5, along with the reappearance of 1
(5i:5:1 of ca. 5:30:2). Additional catecholborane was added to the
reaction mixture (0.010 mL, 0.094 mmol), and after a total reaction
time of 16 days, the quantitative conversion to 5 was detected
spectroscopically (31P NMR). The reaction mixture was concentrated
in Vacuo, which afforded an oily orange solid. The residue was
triturated with pentane (2 × 1.5 mL) and then washed with Et2O
(2 × 1.5 mL) and pentane (1.5 mL). After removal of solvents and
other volatile materials in Vacuo, 5 was isolated as an orange powder
(0.056 g, 0.088 mmol, 54%). Anal. Calcd for C33H43PNBO2Ru: C
63.02; H 6.90; N 2.23. Found: C 62.86; H 6.88; N 2.24. NMR
data for 5i: 1H NMR (C6D6): δ 7.61 (d, 3JHH ) 8.0 Hz, 1H, C4-H
or C7-H), 7.30 (t, 3JHH ) 8.0 Hz, 1H, C5-H or C6-H), 7.24 (d,
3JHH ) 7.5 Hz, 1H, C7-H or C4-H), 7.02 (t, 3JHH ) 7.0 Hz, 1H,
C6-H or C5-H), 6.82-6.79 (m, 2H, BO-aryl Hs), 6.76-6.73 (m,
2H, BO-aryl Hs), 3.81 (apparent t, J ) 10.0 Hz, 1H, N-C(Ha)(Hb)-
Ru), 3.41 (m, 1H, P(CHMeaMeb)), 3.23-3.16 (m, 2H, N-C(Ha)(Hb)-
Ru and C1(Ha)(Hb)), 2.94 (m, 1H, C1(Ha)(Hb)), 2,32 (s, 3H, NMe),
2.09 (m, 1H, P(CHMecMed)), 1.71 (s, 15H, C5Me5), 1.40 (d of d,
Synthesis of 6. Mesitylborane (0.016 g, 0.12 mmol) was added
to a glass vial containing a bright orange solution of 1 (0.060 g,
0.12 mmol) in benzene (6 mL). After the vial was sealed with a
PTFE-lined cap, the solution was shaken manually several times.
31P NMR data collected on an aliquot of this solution indicated
quantitative conversion to 6 within 0.5 h; after this time period the
solution was dull orange. The benzene solvent and other volatile
materials were removed in Vacuo, which left an oily orange solid.
The residue was triturated with pentane (2 × 1.5 mL) and then
washed with pentane (1 mL). After removal of trace amounts of
pentane in Vacuo, 6 was isolated as a yellow-orange powder (0.061
g, 0.095 mmol, 81%). Anal. Calcd for C36H53PNBRu: C 67.24; H
8.31; N 2.18. Found: C 66.95; H 8.46; N 2.11. 1H NMR (C6D6): δ
7.52 (d, 3JHH ) 7.5 Hz, 1H, C4-H or C7-H), 7.24 (t, 3JHH ) 7.5
Hz, 1H, C5-H or C6-H), 7.17-7.10 (m, 2H, aryl Hs), 7.01 (s,
2H, B-aryl Hs), 4.33-4.24 (m, 2H, N-C(Ha)(Hb)-B), 3.39 (m, 1H,
C(Ha)(Hb)), 3.03 (m, 1H, P(CHMeaMeb)), 2.88 (m, 1H, C(Ha)(Hb)),
2.62 (s, 6H, B-aryl o-Me), 2.59 (s, 3H, NMe), 2.35 (s, 3H, B-aryl
p-Me), 2.25 (m, 1H, P(CHMecMed)), 1.37 (d, J ) 1.5 Hz, 15H,
3
3
C5Me5), 1.33 (d of d, JPH ) 10.0 Hz, JHH ) 7.0 Hz, 3H,
3
3
P(CHMecMed)), 1.24 (d of d, JPH ) 16.0 Hz, JHH ) 7.0 Hz, 3H,
P(CHMeaMeb)), 1.17 (d of d, 3JPH ) 17.0 Hz, 3JHH ) 7.0 Hz, 3H,
3
3
P(CHMeaMeb)), 0.90 (d of d, JPH ) 16.0 Hz, JHH ) 7.0 Hz, 3H,
P(CHMecMed)), -11.27 (br s, 1H, Ru-H-B). 13C{1H} NMR
(C6D6): δ 178.1 (d, JPC ) 21.0 Hz, C2), 145.8 (B-aryl C), 145.0
(d, JPC ) 3.9 Hz, C3a or C7a), 142.6 (o-B-aryl C), 142.1 (d, JPC
3.2 Hz, C7a or C3a), 136.1 (d, JPC ) 22.4 Hz, C3), 133.3 (p-B-
aryl C), 128.8 (B-aryl CHs), 126.7 (C5 or C6), 125.1 (aryl CH),
125.0 (aryl CH), 122.7 (C4 or C7), 82.5 (C5Me5), 67.7 (br m,
N-CH2-B), 57.2 (NMe), 29.8 (d, 3JPC ) 8.8 Hz, C1), 26.4 (d,1JPC
2
)
1

Ruthenium Carbene ReactiVity
Organometallics, Vol. 28, No. 1, 2009 83
) 20.4 Hz, P(CHMecMed)), 25.9 (2 B-aryl o-Me), 24.5 (d, 1JPC
)
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. Additional
crystallographic information is provided in the deposited CIF. All
thermal ellipsoid plots were generated by use of ORTEP-3 for
Windows version 1.074.20
2
25.7 Hz, P(CHMeaMeb)), 21.3 (B-aryl p-Me), 20.6 (d, JPC ) 5.8
2
Hz, P(CHMecMed)), 20.0 (d, JPC ) 6.9 Hz, P(CHMecMed)),
19.5-19.3 (m, P(CHMeaMeb)), 11.0 (C5Me5). 31P{1H} NMR (C6D6):
δ 67.1. 11B{1H} NMR (C6D6): δ -18.3 (br). FTIR (NaCl; cm-1
)
ν(B-H): 2297. Slow evaporation of a C6D6 solution of 6 provided
a suitable crystal for single-crystal X-ray diffraction studies.
Acknowledgment. The Natural Sciences and Engineering
Research Council (NSERC) of Canada (including a Discov-
ery Grant for M.S. and a Postgraduate Scholarship for
M.A.R.), the Canada Foundation for Innovation, the Nova
Scotia Research and Innovation Trust Fund, and Dalhousie
University are acknowledged for their generous support of
this work. We also thank the Atlantic Region Magnetic
Resonance Center (Dalhousie University) for assistance in
the acquisition of NMR data, as well as Professor Alex Bain
(McMaster University) for advice regarding selective inver-
sion NMR experiments and for providing the CIFIT program
used in the ensuing data analysis.
Crystallographic Characterization of 2 · PMe3, 3a, 3b, 3d,
5, and 6. Crystallographic data were obtained at 193((2) K on a
Bruker PLATFORM/SMART 1000 CCD diffractometer (except for
3a, for which data were collected by using a Siemens P4/RA
diffractometer) using graphite-monochromated Mo KR (λ )
0.71073 Å) radiation, employing samples that were mounted in inert
oil and transferred to a cold gas stream on the diffractometer.
Programs for diffractometer operation, data collection, and data
reduction (including SAINT and SADABS) were supplied by
Bruker. Gaussian integration was employed as the absorption
correction method for 3a, 3b, 3d, and 5, while SADABS was used
for 2 · PMe3 and 6. For 3a, 3b, 3d, and 5, the structure was solved
by use of direct methods, while for 2 · PMe3 and 6, a Patterson
search/structure expansion was employed. Refinements were carried
out by use of full-matrix least-squares procedures (on F2) with R1
Supporting Information Available: Single-crystal X-ray dif-
fraction data in CIF format for 2 · PMe3, 3a, 3b, 3d, 5, and 6 are
available free of charge via the Internet at http://pubs.acs.org.
2
2
2
2
based on Fo g 2σ(Fo ) and wR2 based on Fo g -3σ(Fo ).
Anisotropic displacement parameters were employed throughout
for the non-hydrogen atoms. The B-H, Si-H (except for in 3d).
and Ru-H positions were located in the Fourier difference map
and refined freely, with the exception that the Ru-H distance in
3d was restrained to be 1.60(2) Å. Otherwise, all hydrogen atoms
OM800761C
(20) Farrugia, L. J. ORTEP-3 for Windows version 1.074. J. Appl.
Crystallogr. 1997, 30, 565.