Indenyl hemilability: Unveiling a masked (η5-C 5Me5)Ru(κ2-P,carbene) zwitterion via facile and reversible Ru-C(sp3) bond cleavage

Article abstract of DOI:10.1021/om800740z

Data obtained from dynamic NMR investigations and reactivity studies revealed that the isolable, 18-electron Cp*Ru(κ³-P,C,C) complex 3 provides access to the reactive, coordinatively unsaturated Cp*Ru(κ²P,C) zwitterionic intermediate 4 by way of an unprecedented and reversible Ru-C(sp³) bond cleavage process that can be described as 'indenyl hemilability'. Indirect support for the reversible generation of 4 from 3 was obtained through the isolation of adducts of the type 4 ?L upon treatment of 3 with various L-donor substrates (L = CO, PPh ₃, PHPh₂, 4-dimethylaminopyridine, NH₃, piperidine, and 2,6dimethylaniline). The reactivity observed upon treatment of 3 with E-H containing substrates (H₂,ⁱPrOH, Ph ₃SiH, Ph₂SiH₂, PhNH₂, and pyrrole) can be rationalized in terms of net cooperative substrate activation involving the Lewis acidic metal fragment and the Lewis basic indenide unit in the reactive intermediate 4. In the apparent reaction of 4 with PHPh₂ and PH₂Ph, an unusual ancillary ligand rearrangement involving the net metathesis of P-H and C-N bonds was observed, resulting in the formation of zwitterionic Cp*Ru(=CH(NHMe))(κ²-P,P) complexes that feature the first examples of κ²-P,P-indenide ligation.

Full text of DOI:10.1021/om800740z

6286
Organometallics 2008, 27, 6286–6299
Indenyl Hemilability: Unveiling a Masked
(η5-C5Me5)Ru(K2-P,Carbene) Zwitterion Via Facile and Reversible
Ru-C(sp3) Bond Cleavage
Matthew A. Rankin,† Gabriele Schatte,‡ Robert McDonald,§ and Mark Stradiotto*,†
Department of Chemistry, Dalhousie UniVersity, Halifax, NoVa Scotia B3H 4J3, Canada, Saskatchewan
Structural Sciences Centre, UniVersity of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada, and
X-Ray Crystallography Laboratory, Department of Chemistry, UniVersity of Alberta,
Edmonton, Alberta T6G 2G2, Canada
ReceiVed July 31, 2008
Data obtained from dynamic NMR investigations and reactivity studies revealed that the isolable, 18-
electron Cp*Ru(κ3-P,C,C′) complex 3 provides access to the reactive, coordinatively unsaturated Cp*Ru(κ2-
P,C) zwitterionic intermediate 4 by way of an unprecedented and reversible Ru-C(sp3) bond cleavage
process that can be described as ‘indenyl hemilability’. Indirect support for the reversible generation of
4 from 3 was obtained through the isolation of adducts of the type 4 · L upon treatment of 3 with various
L-donor substrates (L ) CO, PPh3, PHPh2, 4-dimethylaminopyridine, NH3, piperidine, and 2,6-
dimethylaniline). The reactivity observed upon treatment of 3 with E-H containing substrates (H2, iPrOH,
Ph3SiH, Ph2SiH2, PhNH2, and pyrrole) can be rationalized in terms of net cooperative substrate activation
involving the Lewis acidic metal fragment and the Lewis basic indenide unit in the reactive intermediate
4. In the apparent reaction of 4 with PHPh2 and PH2Ph, an unusual ancillary ligand rearrangement involving
the net metathesis of P-H and C-N bonds was observed, resulting in the formation of zwitterionic
Cp*Ru()CH(NHMe))(κ2-P,P) complexes that feature the first examples of κ2-P,P-indenide ligation.
in hydrogenation catalysis,4 as well as by Milstein and co-
Introduction
workers on the use of hemilabile (κ3-P,N,N)Ru species in both
The design and construction of new and reactive classes of
coordinatively unsaturated platinum-group metal (PGM) com-
plexes represents a crucial step toward addressing challenging
stoichiometric and/or catalytic substrate transformations. In
moving beyond traditional ancillary ligand design themes,1
considerable research effort is being directed toward the pursuit
of complexes supported by ancillary ligands featuring added
functionality that are capable of: (a) providing stability to a
resting state of a complex while also providing access to
reactive, coordinatively unsaturated species by way of a
reversibleligandbinding/reorganizationprocess(e.g.,cyclometalation,2a-c
ꢀ-hydride elimination,2b-e hemilabile chelation,2f,g and other2h,i);
and/or (b) promoting substrate bond activation processes through
cooperative metal-ligand interactions.1,3 In the context of Ru-
mediated E-H (E ) main group element) bond activation
chemistry, landmark studies by Noyori and co-workers on the
application of coordinatively unsaturated amido-Ru complexes
the dehydrogenation of alcohols into esters5a and the dehydro-
genative synthesis of amides from alcohols and amines,5b
exemplify the way in which new and unusual reactivity
manifolds can be accessed by use of coordinatively unsaturated
metal complexes supported by appropriately designed ancillary
ligands that feature a reactive (nondative) Lewis basic
functionality.
In keeping with these themes, we have initiated a research
program focused on the synthesis and reactivity of coordina-
tively unsaturated platinum-group metal complexes supported
by donor-substituted indenide ligands (including κ2-2-NMe2-3-
PiPr2-indenide) that feature a formally cationic metal fragment
counterbalanced by a sequestered, uncoordinated 10π-electron
carbanion built into the backbone of the bidentate ancillary
ligand.6 We view such zwitterions as being appealing candidates
for applications in E-H bond activation chemistry owing to
the potential for net cooperative reactivity involving the Lewis
acidic metal fragment and the Lewis basic indenide unit in these
formally charge-separated complexes. Although we have yet
to document unambiguously such cooperativity in stoichiometric
E-H activation studies involving (κ2-2-NR2-3-PR′2-
* To whom correspondence should be addressed. E-mail:
mark.stradiotto@dal.ca.
† Dalhousie University.
‡ University of Saskatchewan.
§ University of Alberta.
(1) Gru¨tzmacher, H. Angew. Chem., Int. Ed. 2008, 47, 1814.
(2) For some recent noteworthy examples and reviews, see: (a) Lu, C. C.;
Saouma, C. T.; Day, M. W.; Peters, J. C. J. Am. Chem. Soc. 2007, 129, 4.
(b) Figueroa, J. S.; Cummins, C. C. J. Am. Chem. Soc. 2003, 125, 4020.
(c) Figueroa, J. S.; Cummins, C. C. Dalton Trans. 2006, 2161. (d)
Gavenonis, J.; Tilley, T. D. J. Am. Chem. Soc. 2002, 124, 8536. (e)
Kuznetsov, V. F.; Abdur-Rashid, K.; Lough, A. J.; Guzev, D. G. J. Am.
Chem. Soc. 2006, 128, 14388. (f) Ritter, T.; Day, M. W.; Grubbs, R. H.
J. Am. Chem. Soc. 2006, 128, 11768. (g) Slone, C. S.; Weinberger, D. A.;
Mirkin, C. A. Prog. Inorg. Chem. 1999, 48, 233. (h) Fout, A. R.; Basuli,
F.; Fan, H.; Tomaszewski, J.; Huffman, J. C.; Baik, M.-H.; Mindiola, D. J.
Angew. Chem., Int. Ed. 2006, 45, 3291. (i) Turculet, L.; Feldman, J. D.;
Tilley, T. D. Organometallics 2004, 23, 2488.
(3) For selected reviews pertaining to amido platinum-group metal
chemistry, see: (a) Ito, M.; Ikariya, T. Chem. Commun. 2007, 5134. (b)
Ikariya, T.; Blacker, A. J. Acc. Chem. Res. 2007, 40, 1300. (c) Ikariya, T.;
Murata, K.; Noyori, R. Org. Biomol. Chem. 2006, 4, 393. (d) Clapham,
S. E.; Hadzovic, A.; Morris, R. H. Coord. Chem. ReV. 2004, 248, 2201.
(4) Selected examples: (a) Noyori, R. Angew. Chem., Int. Ed. 2002, 41,
2008. (b) Haack, K.-J.; Hashiguchi, S.; Fujii, A.; Ikariya, T.; Noyori, R.
Angew. Chem., Int. Ed. 1997, 36, 285. (c) Fujii, A.; Hashiguchi, S.; Uematsu,
N.; Ikariya, T.; Noyori, R. J. Am. Chem. Soc. 1996, 118, 2521.
(5) (a) Zhang, J.; Leitus, G.; Ben-David, Y.; Milstein, D. J. Am. Chem.
Soc. 2005, 127, 10840. (b) Gunanathan, C.; Ben-David, Y.; Milstein, D.
Science 2007, 317, 790.
10.1021/om800740z CCC: $40.75
2008 American Chemical Society
Publication on Web 11/08/2008

Indenyl Hemilability
Organometallics, Vol. 27, No. 23, 2008 6287
Scheme 1. Synthesis of 3 and the Reversible Formation of 4 (the Atomic Numbering Scheme Is Provided for Representative
Complexes)
indenide)MLn zwitterions, this behavior may contribute to the
remarkable activity afforded by the zwitterionic precatalyst (η6-
p-cymene)Ru(Cl)(κ2-2-NMe2-3-PiPr2-indenide) in ketone transfer
hydrogenation.6b
unsaturated Cp*Ru(κ2-P,C) zwitterion 4,8 the former was
dissolved in CH2Cl2 in an effort to prepare the Cp*Ru(Cl)(κ2-
P,C) complex 2a (Scheme 1). Upon dissolution of the bright
orange 1 in CH2Cl2, a gradual color change of the solution from
red-orange to dark brown was observed over the course of 6 h,
at which point 31P NMR analysis of the reaction mixture
indicated the clean conversion to 2a; in turn this product was
isolated as an analytically pure orange-brown powder in 96%
yield and characterized. The observation of diagnostic RudCH
In the course of our investigations of the coordinatively
unsaturated zwitterion Cp*Ru(κ2-2-NMe2-3-PiPr2-indenide) (Cp*
) η5-C5Me5), we observed that in the presence of a stabilizing
ligand it is possible to isolate 18-electron species of the type
Cp*Ru(L)(κ2-2-NMe2-3-PiPr2-indenide) (e.g., L ) CH3CN).6d
However, in the absence of such a stabilizing ligand Cp*Ru(κ2-
2-NMe2-3-PiPr2-indenide) rapidly rearranges to the Cp*Ru(H)(κ2-
P, C) hydridocarbene complex (1, Scheme 1) via double geminal
C-H bond activation involving a ligand NMe group; dynamic
NMR data for 1 provided evidence for the first documented
interconversion of Ru(H)dCH (1) and Ru-CH2 (1i) groups by
way of reversible R-hydride elimination.6d We report herein on
the use of 1 as a synthetic precursor to the 18-electron Cp*Ru(κ3-
P,C,C′) species 3. Notably, dynamic NMR data reveal that 3
provides access to the coordinatively unsaturated Cp*Ru(κ2-
P,C) zwitterionic intermediate 4 by way of an unusual new mode
of ancillary ligand hemilability involving reversible Ru-C(sp3)
bond cleavage. Furthermore, reactivity studies confirm that 3
behaves as a masked source of 4, both in reactions with L-donors
(to give 4 · L), as well as in reactions with a range of E-H
containing substrates to give products corresponding to the net
heterolytic cleavage of E-H bonds by the Lewis acidic metal
fragment and the Lewis basic indenide unit in 4.7
1
NMR signals for 2a (δ H ) 12.60, δ 13C ) 246.9; cf 12.09
and 244.1 for 16d) confirmed that the carbene portion of the
κ2-P,C ligand in 1 remained intact during conversion to 2a. In
solution, the slow conversion of 2a to 2b in CH2Cl2 was detected
(31P NMR) in the absence of observable intermediates (ca. 75%
conversion after 2 weeks). This isomerization process was found
to be accelerated in the presence of excess NEt3, thereby
enabling the isolation of analytically pure 2b in 91% yield.
In an effort to exploit the chlorocarbene 2a as a precursor to
4 via dehydrohalogenation, 2a was treated with NaN(SiMe3)2
and the progress of the reaction was monitored by use of 31P
NMR methods. Complete conversion to a new phosphorus-
containing product was observed over the course of 45 min,
which in turn was isolated in 81% yield. While elemental
analysis data for this new product were found to be consistent
with the dehydrohalogenation of 2a, NMR spectroscopic and
X-ray crystallographic data confirmed the identity of this species
as the C1-symmetric, 18-electron Cp*Ru(κ3-P,C,C′) complex
3. An ORTEP9 diagram of one of the two crystallographically
independent molecules of 3 is provided in Figure 1, while
crystallographic data and selected interatomic distances for all
of the crystallographically characterized compounds reported
herein are collected in Tables 1 and 2, respectively. Some of
the core structural features in 3 can be compared with a related
(η6-arene)Ru(Cl)(κ2-iPr2P-CHCO2Me) complex reported by
Results and Discussion
Pursuit of the Zwitterion 4. In viewing the hydridocarbene
1 as a starting point in the synthesis of the coordinatively
(6) Complexes of donor-substituted indenide ligands are described as
zwitterionic in that they lack conventional resonance structures that would
enable the indenide anionic charge to be delocalized onto the pendant donor
atoms. For (κ2-P, N)-PGM complexes, see: (a) Lundgren, R. J.; Rankin,
M. A.; McDonald, R.; Stradiotto, M. Organometallics 2008, 27, 254. (b)
Lundgren, R. J.; Rankin, M. A.; McDonald, R.; Schatte, G.; Stradiotto, M.
Angew. Chem., Int. Ed. 2007, 46, 4732. (c) Cipot, J.; McDonald, R.;
Ferguson, M. J.; Schatte, G.; Stradiotto, M. Organometallics 2007, 26, 594.
(d) Rankin, M. A.; McDonald, R.; Ferguson, M. J.; Stradiotto, M.
Organometallics 2005, 24, 4981.
(8) The utility of coordinatively unsaturated Cp*RuLn complexes in
mediating E-H bond activation is well-established. For selected reviews,
see (a) Bruneau, C.; Renaud, J.-L.; Demerseman, B. Chem. Eur. J. 2006,
12, 5178. (b) Trost, B. M.; Frederiksen, M. U.; Rudd, M. T. Angew. Chem.,
Int. Ed. 2005, 44, 6630. (c) Jime´nez-Tenorio, M.; Puerta, M. C.; Valerga,
P. Eur. J. Inorg. Chem. 2004, 17. (d) Nagashima, H.; Kondo, H.; Hayashida,
T.; Yamaguchi, Y.; Gondo, M.; Masuda, S.; Miyazaki, K.; Matsubara, K.;
Kirchner, K. Coord. Chem. ReV. 2003, 245, 177. (e) Davies, S. G.; McNally,
J. P.; Smallridge, A. J. AdV. Inorg. Chem. 1990, 30, 1.
(7) A portion of these results has been communicated previously: Rankin,
M. A.; Schatte, G.; McDonald, R.; Stradiotto, M. J. Am. Chem. Soc. 2007,
129, 6390.
(9) ORTEP-3 for Windows version 1.074: Farrugia, L. J. J. Appl.
Crystallogr. 1997, 30, 565.

6288 Organometallics, Vol. 27, No. 23, 2008
Rankin et al.
Scheme 2. Proposed Interconversion of Enantiomeric Forms
of 3 via the Cs-Symmetric Intermediate 4a
a
“R” and “S” refer to the configuration at C-1.
Figure 1. ORTEP diagrams for 3 (left) and 4 · DMAP (right), shown
with 50% displacement ellipsoids and with the atomic numbering
scheme depicted; only one of the two crystallographically inde-
pendent molecules of 3 is presented, and selected H-atoms have
been omitted for clarity (DMAP ) 4-dimethylaminopyridine).
Å).14b As such, the remarkable ease with which the Ru-C1
linkage undergoes formal heterolytic cleavage in the reversible
transformation of 3 into 4 may be attributable in part to the
relief of ring strain in the κ3-P,C,C′ complex 3, as well as to
the energetic favorability of generating a Hu¨ckel aromatic
indenide anion within the zwitterion 4, upon ring opening.
Reaction of 3 with CO and DMAP. Intrigued by the
possibility that the dynamic behavior of 3 might allow for this
complex to serve as a reactive source of the originally targeted
coordinatively unsaturated zwitterion 4, we sought to canvas
the stoichiometric reactivity of 3 with a range of small molecule
substrates. In initial investigations employing simple L-donors,
a solution of 3 was exposed to either an equivalent of
4-dimethylaminopyridine (DMAP) or an atmosphere of CO
(Scheme 3). In each case the clean formation of the correspond-
ing adduct 4 · L (L ) DMAP, 95%; L ) CO, 96%) provided
indirect support for the ability of 3 to provide access to 4 in
situ. The facile Ru-C(sp3) bond cleavage observed in the course
of transforming 3 into 4 · CO contrasts the chemistry exhibited
by Cp*Ru(κ3-HC(PPh2NPh)2) upon exposure to CO, whereby
a Cp*Ru(CO)(κ2-N,C,N) adduct arising from net substitution
of an ancillary ligand N-donor arm is produced.14a
Werner and co-workers.10 While each of the Ru-P distances
in 3 is shorter than that of the comparator complex, the
i
corresponding Ru-C1 and Pr2P-C distances in 3 are signifi-
cantly longer, suggesting less PdC character in 3 possibly
resulting from the structural requirements of the tridentate κ3-
P,C,C′ ligand.11
Dynamic Behavior of 3. Given the somewhat unusual
connectivity in 3, we sought to explore the dynamic properties
of this complex in solution. In this regard, data from 1D- and
2D-EXSY 1H NMR12 experiments provided definitive spectro-
scopic evidence for the operation of an unprecedented and
reversible Ru-C(sp3) bond cleavage process involving 3. In the
case of 1D-EXSY experiments, irradiation of either of the
diastereotopic P(CHMe2)2 resonances resulted in significant
positively phased enhancement of the other methine signal, in
keeping with chemical exchange involving these two environ-
ments. Moreover, the 2D-EXSY spectra of 3 featured positively
phased off-diagonal exchange cross-peaks that correlate the two
diastereotopic P(CHMe2)2 environments, as well as pairs of
P(CHMe2)2 resonances. Collectively, these spectroscopic ob-
servations can be rationalized in terms of the reversible cleavage
of the Ru-C1 linkage in 3, thereby providing access to the
coordinatively unsaturated, CS-symmetric zwitterionic interme-
diate 4 (Schemes 1 and 2). It is noteworthy that this dynamic
process is distinct from conventional cyclometalation or ꢀ-hy-
dride elimination reactions commonly associated with the
breaking and reforming of M-C(sp3) linkages; given that the
reversible Ru-C(sp3) bond cleavage process in 3 occurs without
a change in formal oxidation state at Ru, this novel dynamic
process is perhaps best described as “indenyl hemilability”.13
Each of the Ru-C1 distances in 3 (2.250(2) Å, 2.245(2) Å) is
not unusually long, exhibiting values that fall between those of
the related tridentate complexes Cp*Ru(κ3-HC(PPh2NPh)2)
(2.273(2) Å)14a and (η6-p-cymene)Ru(κ3-HC(PPh2NPh)2) (2.224(3)
Scheme 3. Preparation of 4 · L and an Important Resonance
Contributor (4 · L′) for This Class of Complexesa
a
L ) CO or 4-Dimethylaminopyridine, DMAP.
Both 4 · CO and 4 · DMAP were characterized spectroscopi-
cally, and crystallographic data were also obtained for
4 · DMAP; an ORTEP9 diagram of this complex is presented
in Figure 1. The carbocyclic backbone in 4 · DMAP (as well as
in the related adducts 4 · NC8H11 and 4 · PPh3, Vide infra;
NC8H11 ) 2,6-dimethylaniline) exhibits C-C distances that are
consistent with a delocalized 10π-electron indenide unit, as has
been observed for other crystallographically characterized donor-
substituted indenide complexes.6 However, while the formally
zwitterionic 4 · DMAP lacks a conventional resonance structure
that places the anionic charge onto either the carbene or
phosphine donor fragments, the relatively short P-C3 and
C1-C2 distances in this adduct (1.779(3) and 1.390(5) Å)
indicate that a less-conventional non-zwitterionic resonance
contributor featuring a PdC3 bond, which places the anionic
charge on phosphorus, may also figure prominently in 4 · DMAP
(10) Henig, G.; Schulz, M.; Werner, H. Chem. Commun. 1997, 2349.
(11) For related crystallographically characterized Ru(κ2-Ph2P-CHX)
´
complexes, see: Cadierno, V.; D´ıez, J.; Garc´ıa-Alvarez, J.; Gimeno, J
Organometallics 2004, 23, 3425, and references cited therein.
(12) For discussions regarding exchange (NMR) spectroscopy, see: (a)
Perrin, C. L.; Dwyer, T. J. Chem. ReV. 1990, 90, 935. (b) Perrin, C. L.;
Engler, R. E. J. Am. Chem. Soc. 1997, 119, 585.
(13) The conceptually related interconversion between κ2-P,P and κ3-
P,N,P species, involving the breaking and reforming of a dative amine-Ru
linkage in Cp*Ru({iPr2PNH}2C6H10), has been reported recently: Palacios,
M. D.; Puerta, M. C.; Valerga, P.; Lledo´s, A.; Veilly, E Inorg. Chem. 2007,
46, 6958.
(14) (a) Bibal, C.; Smurnyy, Y. D.; Pink, M.; Caulton, K. G. J. Am.
Chem. Soc. 2005, 127, 8944. (b) Bibal, C.; Pink, M.; Smurnyy, Y. D.;
Tomaszewski, J.; Caulton, K. G. J. Am. Chem. Soc. 2004, 126, 2312.

Indenyl Hemilability
Organometallics, Vol. 27, No. 23, 2008 6289
Table 1. Crystallographic Data for 3, 4 · DMAP, 4 · NC8H11(2.5NC8H11), 4 · PPh3(C6H6), 8, 12(C6H6)2.5, and 13
4 · NC8H11
(2.5NC8H11)
4 · PPh3
(C6H6)
3
4 · DMAP
8
12(C6H6)2.5
13
Empirical formula
Formula weight
C27H38NPRu
508.62
C34H48N3PRu
670.79
C55H76.5N4.5PRu
932.75
C51H59NP2Ru
849.00
C39H50NPRuSi
692.93
C54H64NP2Ru
890.07
C33H45NP2Ru
619.72
Crystal dimensions
0.62 × 0.33
0.15 × 0.10
0.60 × 0.57
0.30 × 0.20
0.10 × 0.08
0.20 × 0.20
0.15 × 0.15
× 0.28
× 0.10
× 0.14
× 0.20
× 0.08
× 0.20
× 0.10
Crystal system
Space group
a (Å)
b (Å)
c (Å)
R (deg)
ꢀ (deg)
γ (deg)
V (Å3)
triclinic
triclinic
triclinic
orthorhombic
Pbca
15.9860(2)
22.7080(4)
23.8110(2)
90
90
90
8643.6(2)
8
1.305
triclinic
triclinic
triclinic
j
j
j
j
j
j
P1
P1
P1
P1
P1
P1
8.3256(5)
15.1105(10)
21.0117(14)
84.0995(9)
79.3200(9)
78.8049(9)
2542.0(3)
4
8.8300(3)
10.9600(4)
17.1350(5)
87.246(2)
83.675(2)
69.536(2)
1544.08(9)
2
10.9510 (9)
14.3673 (12)
16.7877 (13)
84.2967 (11)
77.9902 (10)
73.5579 (10)
2475.5 (3)
2
9.4870(17)
11.844(2)
16.851(4)
98.505(10)
101.400(8)
107.029(9)
1731.4(6)
2
12.9030(16)
12.9220(10)
15.8990(12)
74.415(3)
71.476(5)
70.052(4)
2324.2(4)
2
8.8150(4)
10.6730(4)
18.0270(8)
76.406(2)
75.879(3)
69.245(2)
1517.25(11)
2
Z
Fcalcd (g cm-3
)
1.329
0.693
1.357
0.587
1.251
0.389
1.329
0.561
1.272
0.442
1.354
0.644
µ (mm-1
)
0.472
Range of transmission
2θ limit (deg)
0.8296-0.6732
52.78
0.9437-0.9173
54.96
0.9475-0.8000
54.86
0.9115-0.8713
60.06
0.9565-0.9460
43.94
0.9167-0.9011
56.38
0.9384-0.9095
52.74
Index ranges
-10 e h e 10
-18 e k e 18
-26 e l e 26
19436
10336
0.0170
-11 e h e 11
-14 e k e 14
-22 e l e 22
11746
7037
0.0473
-13 e h e 14
-18 e k e 18
-21 e l e 21
21645
11137
0.0156
-22 e h e 22
-31 e k e 31
-33 e l e 33
24114
12615
0.0387
0 < h < 9
-12 e k e 11
-17 e l e 16
4135
4135
na
-16 < h < 17
-17 e k e 17
-20 e l e 20
19505
11368
0.0532
-11 < h < 10
-12 e k e 13
-22 e l e 22
10370
6164
0.0508
Total data collected
Independent reflections
Rint
Observed reflections
Data/restraints/parameters
Goodness-of-fit
9377
10336/0/553
1.089
0.0247
0.0691
5714
7037/0/364
1.043
0.0459
0.1020
9997
11137/9/544
1.060
0.0370
0.1016
9406
12615/0/506
1.029
0.0405
0.0974
3036
4135/145/402
1.045
0.0631
0.1436
9493
11638/0/536
1.021
0.0413
0.0906
4947
6164/0/348
1.061
0.0428
0.1009
2
R1 [ Fo g 2σ(Fo2)]
2
wR2 [ Fo g -3σ(Fo2)]
Largest peak, hole (e Å-3
)
0.316 and -0.670 0.793 and -0.785 1.284 and -0.561 0.663 and -0.604 0.602 and -0.579 0.611 and -1.106 0.754 and -0.587
Table 2. Selected Interatomic Distances (Å) for 3, 4 · DMAP, 4 · NC8H11(2.5NC8H11), 4 · PPh3(C6H6), 8, 12(C6H6)2.5, and 13
d
3a
3b
4 · DMAPc
4 · NC8H11
4 · PPh3
8e
12f
13g
Ru-P1
2.2158(5)
-
2.2206(5)
-
2.3011(9)
-
2.3139(5)
-
2.3242(6)
2.3297(5)
1.963(2)
1.323(3)
1.478(3)
1.424(3)
1.776(2)
1.392(3)
1.411(3)
1.433(3)
1.433(3)
1.412(3)
1.380(3)
1.406(3)
1.372(4)
1.407(3)
1.446(3)
2.295(2)
2.3362(6)
2.2899(6)
1.964(2)
1.311(3)
1.458(3)
2.3160(9)
2.2639(9)
1.980(4)
1.306(5)
1.455(5)
Ru-P2
-
-
1.47(1)
RudC
1.941(2)
1.346(2)
1.463(2)
1.397(2)
1.805(2)
1.468(2)
1.475(3)
1.361(3)
1.445(3)
1.392(3)
1.380(3)
1.394(3)
1.394(3)
1.388(3)
1.428(3)
1.936(2)
1.355(3)
1.461(3)
1.389(3)
1.802(2)
1.462(3)
1.482(3)
1.365(3)
1.432(4)
1.411(4)
1.374(6)
1.372(6)
1.388(4)
1.390(4)
1.419(4)
1.949(3)
1.329(4)
1.472(4)
1.425(4)
1.779(3)
1.390(5)
1.420(5)
1.423(4)
1.434(4)
1.407(5)
1.374(5)
1.406(5)
1.370(5)
1.404(5)
1.445(4)
1.946(2)
1.328(3)
1.471(3)
1.427(3)
1.790(2)
1.391(3)
1.412(3)
1.428(3)
1.433(3)
1.413(3)
1.381(3)
1.404(4)
1.373(4)
1.402(3)
1.445(3)
RuC-N
N-CH3
N-C2
1.46(1)
1.37(1)
1.889(7)
1.52(1)
1.50(1)
1.37(1)
1.44(1)
1.38(1)
1.37(1)
1.38(1)
1.40(1)
1.37(1)
1.41(1)
-
-
iPr2P-Cind
C1-C2
C1-C7a
C2-C3
C3-C3a
C3a-C4
C4-C5
C5-C6
C6-C7
C7-C7a
C3a-C7a
1.781(2)
1.400(3)
1.415(3)
1.424(3)
1.434(3)
1.413(3)
1.380(3)
1.401(4)
1.372(4)
1.412(3)
1.450(3)
1.779(3)
1.394(5)
1.420(5)
1.435(5)
1.427(5)
1.407(5)
1.377(5)
1.399(6)
1.376(5)
1.403(5)
1.440(5)
a In the first crystallographically independent molecule of 3, Ru-C1 ) 2.250(2) Å. b In the second crystallographically independent molecule of 3,
Ru-C1 ) 2.245(2) Å. c Ru-N31 ) 2.147(3) Å. d Ru-N2 ) 2.256(2) Å. e Ru-Si ) 2.391(2) Å; Ru-H ) 1.48(9) Å; Ru-CH2 ) 2.169(8) Å; Si-C1
) 1.958(8) Å; Ru-H-Si ) 1.90(8) Å. f P2-C2 ) 1.798(2) Å. g P2-C2 ) 1.796(3) Å; P-H ) 1.35(4) Å.
(as well as in 4 · NC8H11 and 4 · PPh3).15 Furthermore, the
planarity of the N1 atom (Σangles at N1 ca. 360°) and the relatively
short Ru-C27 (RudC, 1.949(3) Å) and N-C27 (RuC-N,
1.329(4) Å; cf N-CH3, 1.472(4) Å) distances in 4 · DMAP point
to significant π-bonding interactions along the Ru-C-N
fragment, thereby underscoring the potential importance of
resonance contributors of the type 4 · L′ (Scheme 3) in describing
the electronic structure of 4 · DMAP and related 4 · L adducts.
Reaction of 3 with H2, iPrOH, and Organosilanes. Encour-
aged by the apparent ability of 3 to behave as a masked source
of the zwitterion 4 in reacting with the L-donors CO and DMAP,
we proceeded to examine the reactivity of 3 with E-H
containing substrates. Exposure of 3 in C6D6 to H2 (ca. 1 atm)
resulted in the clean conversion to 1 after 10 min, in the absence
of observable (1H and 31P NMR) intermediates (Scheme 4).
Similarly, treatment of a C6D6 solution of 3 with excess iPrOH
afforded quantitatively the allylic isomer of 1 (i.e., 1b - the
Ru-H variant of 2b) after 30 min; in turn 1b was observed to
isomerize cleanly to 1 over the course of 24 h (1H and 31P
NMR).16 While in the absence of mechanistic data we are
hesitant to comment conclusively regarding the mechanism of
these chemical transformations, each corresponds to the net
addition of H- and H+ to the Lewis acidic Ru and Lewis basic
indenide fragments (respectively) in 4.
In turning our attention to Si-H containing substrates, a
solution of 3 in C6D6 was treated with an equivalent of Ph3SiH,
and the progress of the reaction was monitored by use of NMR
methods (Scheme 4). After 45 min, the 3:5 ratio was ca. 1:1
(31P NMR), and after 24 h a mixture of 3:5:7 (ca. 2:2:1) was
detected spectroscopically. Continued monitoring of the solution
revealed that a total reaction time of three weeks was needed
(16) The clean isomerization of 1b into 1 has been documented
previously; see ref 6d herein.
(15) Izod, K. Coord. Chem. ReV. 2002, 227, 153.

6290 Organometallics, Vol. 27, No. 23, 2008
Rankin et al.
Scheme 4. Reactions Involving H2, iPrOH, and Organosilanes
Figure 2. ORTEP diagram for 8, shown with 50% displacement
ellipsoids and with the atomic numbering scheme depicted; selected
H-atoms have been omitted for clarity.
terization of 9 (in the presence of 8 as an impurity) was made
possible through the use of 1D- and 2D-NMR spectroscopic
techniques. Analogous reactions involving the treatment of 3
in C6D6 with an equivalent of PhSiH3, pinacolborane, cat-
echolborane, water (5 equiv in THF), or phenylacetylene (24
or 60 °C) each resulted in the formation of an intractable product
mixture.
in order to achieve the quantitative formation of 7, and on a
preparative scale this compound was obtained as an analytically
pure solid in 93% isolated yield. The spectroscopically identified
first-formed product 5 can be viewed as arising from Si-H
oxidative addition to Ru in the reactive intermediate 4, followed
by slow net transfer of H+ from Ru to the indenide fragment to
give 7. An analogous intermediate 6 was identified spectro-
scopically as a kinetic product upon treatment of 3 with Ph2SiH2.
However, unlike the direct transformation of 5 into 7, the
intermediate 6 was observed to rearrange quantitatively to an
alternative, isolable intermediate 8 over the course of 24 h.
Compound 8 was isolated in 91% yield and characterized by
use of spectroscopic and X-ray crystallographic techniques; an
ORTEP9 diagram of 8 is presented in Figure 2. We are reluctant
to comment definitively regarding the location of the hydride
in 8; however, the final refined crystallographic parameters, as
Reaction of 3 with Amines. In building upon the aforemen-
tioned reactivity studies, we sought to evaluate the reactivity
of 3 with group 15 L-donor substrates that also feature E-H
bonds. Treatment of a solution of 3 in C6H6 with an excess of
NH3 (0.5 M in dioxane) or piperidine (NC5H11) afforded cleanly
the corresponding 4 · L adduct (Scheme 5); upon workup each
of 4 · NH3 (75% yield) and 4 · NC5H11 (82% yield) was obtained
as an analytically pure solid. While dissolution of 4 · NH3 (0.023
g) in C6D6 (0.8 mL) resulted in negligible dissociation to give
3 and free NH3 (1H and 31P NMR), dissolution of 4 · NC5H11
(0.019 g) in C6D6 (0.8 mL) produced a mixture of 4 · NC5H11
and 3 (ca. 9:1 on the basis of 31P NMR data), as well as a
1
stoichiometric equivalent of free piperidine (relative to 3; H
2
NMR). In keeping with this trend, when 3 was treated with an
excess of the more sterically demanding substrate 2,6-dimethyl-
aniline (NC8H11) under similar conditions, 31P NMR data
revealed a mixture of 4 · NC8H11 and 3 (ca. 2:1). Upon
concentrating the solution in Vacuo only 4 · NC8H11(δ 31P )
58.9) was observed, and treatment of this mixture with pentane
followed by storage at -35 °C allowed for the isolation of solid
4 · NC8H11, including some crystals of 4 · NC8H11(2.5NC8H11)
that proved to be suitable for X-ray diffraction analysis; an
ORTEP9 diagram of 4 · NC8H11(2.5NC8H11) is presented in
Figure 3. The salient structural features of 4 · NC8H11 mirror
those found in 4 · DMAP (Vide supra). Upon dissolution in C6D6
(0.8 mL), 4 · NC8H11 (0.022 g) was observed to produce
significant quantities of 3 (ca. 80%, 31P NMR), as well as free
2,6-dimethylaniline (1H NMR).
In an effort to observe σ-bond activation chemistry, the
reactivity of 3 with alternative N-H containing substrates was
examined. Treatment of 3 with PhNH2 in C6D6 afforded after
10 min a 1:4 mixture of the apparent N-H activation product
10 (δ 31P ) 76.2), and a second product tentatively assigned as
4 · NH2Ph (δ 31P ) 64.0) on the basis 1H NMR data (by
comparison to 4 · NH3 and 4 · NC5H11). In monitoring further
the progress of the reaction, 31P NMR analysis after 72 h
revealed the presence of 10 and an as-yet-unidentified species
(broad, 62.1 ppm) in a ratio of ca. 10:1. While we have yet to
obtain 10 in the absence of this unknown complex, the identity
of 10 was determined on the basis of 1D- and 2D-NMR
spectroscopic data. The observation of five distinct N-Ph C-H
well as the experimentally determined JSiH value (21.0 Hz),
point to an unsymmetrical Ru-H · · · Si bridging interaction in
this complex.17 While additional mechanistic data are lacking,
the rearrangement of 6 to 8 can be viewed as proceeding via
net 1,3-H transfer from Si to RudC, accompanied by intramo-
lecular nucleophilic attack of the indenide unit on silicon.
Overall, the transformation of 4 into 8 corresponds to the net
extrusion of diphenylsilylene (Ph2Si:) from Ph2SiH2, in which
the cationic Ru fragment and the anionic κ2-P,C ligand in 4
each play a role in the silane activation process.18 Efforts to
prepare a base-stabilized zwitterionic RudSiPh2 complex via
heterolytic cleavage of the Si-indenyl linkage in 8 upon
treatment with DMAP were unsuccessful.19 Periodic monitoring
of a C6D6 solution of 8 (stored at ambient temperature under
N2) revealed the incomplete conversion to 9 (the SiPh2H variant
of 7); after 1 week the ratio of 8:9 was 10:1, while after 5 months
the ratio was observed to be 1:8, with no subsequent conversion
noted. Attempts to accelerate the rearrangement of 8 to 9 upon
heating at 60 °C for 48 h resulted in decomposition, and we
have thus far been unsuccessful in our efforts to isolate 9 in
analytically pure form. Nonetheless, the unambiguous charac-
(17) (a) Lachaize, S.; Sabo-Etienne, S. Eur. J. Inorg. Chem. 2006, 2115.
(b) Corey, J. Y.; Braddock-Wilking, J. Chem. ReV. 1999, 99, 175.
(18) Glaser, P. B.; Tilley, T. D. J. Am. Chem. Soc. 2003, 125, 13640.
(19) We have reported recently zwitterionic RudSi complexes of this
type that feature intramolecular base-stabilization: Rankin, M. A.; MacLean,
D. F.; Schatte, G.; McDonald, R.; Stradiotto, M. J. Am. Chem. Soc. 2007,
129, 15855.

Indenyl Hemilability
Organometallics, Vol. 27, No. 23, 2008 6291
Scheme 5. Reactions Involving Amines
Scheme 6. Reactions Involving Phosphines
1
signals in the H NMR spectrum of 10 indicates that rotation
about the N-Ph axis is slow on the NMR time scale at 300K,
as has been observed in related Ru(NHPh) complexes.20,21 While
N-H oxidative addition to the zwitterion 4 to give an
intermediate analogous to 5 or 6 cannot be unequivocally ruled
out in the absence of mechanistic data,20 we view the formation
of 10 as arising from the net deprotonation (either intra- or
intermolecular) of the coordinated aniline ligand in 4 · NH2Ph
by indenide. In this vein, an adduct of the type 4 · L was not
detected in analogous reactions with 3 employing the more
acidic N-H substrate pyrrole. Rather, treatment of a solution
of 3 in C6H6 with pyrrole afforded only 11 (31P NMR) over the
course of 10 min,21 thereby allowing for the isolation of this
product as an analytically pure solid in 95% yield. Periodic
monitoring (1H and 31P NMR) of a solution of 11 (0.022 g) in
C6D6 (0.8 mL) over the course of 6 h revealed ca. 20%
conversion to a mixture containing what we assign as the vinylic
isomer of 11 (i.e., the Ru-NC4H4 variant of 10; δ 31P ) 61.6),
3, and free pyrrole.
Reaction of 3 with Phosphines. Complex 3 was observed
(31P NMR) to react cleanly in C6H6 with an equivalent of PPh3
over the course of 15 min to give a single product (4 · PPh3),
which in turn was obtained in 96% isolated yield (Scheme 6).
An ORTEP9 diagram of 4 · PPh3(C6H6) is presented in Figure
3. The core structural features of this complex are similar to
those found in the related zwitterionic adducts 4 · NC8H11 and
4 · DMAP (Vide supra). Subsequently, we turned our attention
to reactions involving PHPh2 or PH2Ph in an effort to assess
the ability of the reactive intermediate 4 to promote P-H bond
cleavage reactions.22 Consistent with the formation of 4 · PPh3,
the adduct 4 · PHPh2 was generated initially upon combination
of 3 and PHPh2; 4 · PHPh2 was isolated in 94% yield, and
characterized spectroscopically. However, in monitoring the
stability of 4 · PHPh2 in C6D6 at ambient temperature (1H and
31P NMR), partial conversion to a new phosphorus-containing
product (12) was detected after 36 h, accompanied by the
gradual drop in intensity of the P-H signal in 4 · PHPh2; after
five weeks, this transformation was observed to proceed to
completion. In raising the temperature to 50 °C, the clean
conversion of 4 · PHPh2 into 12 was achieved in only one week,
thereby allowing for the more convenient synthesis of 12 in
1
91% isolated yield. Whereas H NMR data revealed that the
coordinated secondary phosphine ligand in 4 · PHPh2 had
undergone a P-H bond cleavage process in the formation of
(20) For an example of aniline N-H oxidative addition to Ru, see:
Hartwig, J. F.; Anderson, R. A.; Bergman, R. G. Organometallics 1991,
10, 1875.
(21) For pyrrole and related N-H activation by Ru, see: (a) Gunnoe,
T. B. Eur. J. Inorg. Chem. 2007, 1185. (b) Pittard, K. A.; Cundari, T. R.;
Gunnoe, T. B.; Day, C. S.; Petersen, J. L. Organometallics 2005, 24, 5015.
(22) For some recent selected reports and reviews related to late metal-
mediated P-H bond activation, see: (a) Han, L.-B.; Tilley, T. D. J. Am.
Chem. Soc. 2006, 128, 13698. (b) Scriban, C.; Glueck, D. S. J. Am. Chem.
Soc. 2006, 128, 2788. (c) Chan, C. S.; Stewart, I. C.; Bergman, R. G.; Toste,
F. D. J. Am. Chem. Soc. 2006, 128, 2786. (d) Tanaka, M. Top. Curr. Chem.
2004, 232, 25. (e) Alonso, F.; Beletskaya, I. P.; Yus, M. Chem. ReV. 2004,
104, 3079.
Figure 3. ORTEP diagrams for 4 · NC8H11(2.5NC8H11) (left) and
4 · PPh3(C6H6) (right), shown with 50% displacement ellipsoids and
with the atomic numbering scheme depicted; selected H-atoms, as
well as the benzene and 2,6-dimethylaniline (NC8H11) solvates, have
been omitted for clarity.

6292 Organometallics, Vol. 27, No. 23, 2008
Rankin et al.
Scheme 7. Possible Mechanism for the Conversion of
4 · PHPh2 to 12 on the Basis of a Deuterium Labeling Study
Figure 4. ORTEP diagrams for 12(C6H6)2.5 (left) and 13 (right)
shown with 50% displacement ellipsoids and with the atomic
numbering scheme depicted; selected H-atoms and the benzene
solvates have been omitted for clarity.
1
12, both H and 13C NMR data supported the presence of a
as precursors to κ2-P,P-indenide complexes. The results of such
RudCH fragment in this product, thereby precluding the
assignment of 12 as being a product arising from P-H bond
addition across the RudC fragment. Moreover, the absence of
a Ru-H 1H NMR resonance, and observation of a signal
attributable to an N-H unit served to rule out 12 as being
derived from net P-H oxidative addition to the reactive
intermediate 4. The identity of 12 as a new zwitterionic
Cp*Ru(dCH(NHMe))(κ2-P,P) complex derived from net me-
tathesis of C-N and P-H bonds in the κ2-P,C species 4 · PHPh2
was confirmed by use of X-ray crystallographic techniques (Vide
infra). Treatment of 3 with PH2Ph in C6H6 at ambient temper-
ature resulted in the complete consumption of 3 after 15 min,
accompanied by the formation of a mixture of phosphorus-
containing products. After a total reaction time of 24 h, 31P NMR
data obtained from an aliquot of the reaction mixture revealed
the presence of two major phosphorus-containing products (2:1
ratio): the new zwitterionic Cp*Ru(dCH(NHMe))(κ2-P,P)
complex 13 (related to 12), as well an as-yet-unidentified
intermediate (possibly 4 · PH2Ph).23 Continued monitoring of
the reaction mixture (31P NMR) revealed the presence of only
13 after a total reaction time of 72 h, thereby enabling the
isolation of this complex in 88% yield.
synthetic investigations will be reported elsewhere.
In an effort to gain some insight into the mechanistic pathway
linking 4 · PHPh2 and 12, compound 3 (0.020 g) in benzene
(0.8 mL) was treated with 1.0 or 1.5 equiv of PDPh2 and the
progress of the reaction was monitored by use of NMR methods
(Scheme 7). Reactions employing 1.0 equiv of PDPh2 afforded
4 · PDPh2 cleanly after 15 min. After 24 h at ambient temper-
ature, 1H and 2H NMR analysis indicated partial conversion of
4 · PDPh2 to a new deuterium-containing species (i.e., 4 · PHPh2-
d1), as evidenced by partial deuterium incorporation in the
C3-H position, as well as the appearance of a 1H NMR signal
attributable to the P-H group in 4 · PHPh2. When 3 was treated
with 1.5 equivalents of PDPh2 under similar conditions, 4 · PD-
Ph2 once again was observed as the first formed product after
15 min, along with unreacted PDPh2. However, NMR analysis
of the reaction mixture after storage for 24 h at ambient
temperature revealed the formation of 4 · PHPh2-dn, which
exhibited more significant deuterium incorporation at the C3-H
position than was observed when employing an equimolar
amount of PDPh2, as well as free PHPh2 and PDPh2. Such
spectroscopic observations are consistent with the intermediacy
of a Ru-PPh2 complex such as 12i-dn (or 12i-dn), which could
arise via reversible deprotonation of the P-D(H) unit (either
intra- or intermolecular) by the indenide fragment in 4 · PHPh2-
dn (or 4 · PHPh2-dn) (Scheme 7). After each mixture mentioned
above was heated at 50 °C for 1 week, the quantitative formation
of 12-d1 (or 12-dn) was noted; in both cases NMR analyses
indicated deuterium incorporation at the N-H and C3-H
positions exclusively. Collectively, these qualitative observations
are in keeping with a mechanism in which 4 · PHPh2 exists in
equilibrium with an intermediate such as 12i (similar to the
amido complex 10). Nucleophilic attack (either intramolecular
as depicted in Scheme 7, or intermolecular) of the phosphido
fragment on indene in this or a related intermediate, ac-
companied by net deprotonation of the indene moiety by
nitrogen, affords 12.25
An ORTEP9 diagram for each of 12(C6H6)2.5 and 13 is
presented in Figure 4. The salient structural features associated
with these new κ2-P,P zwitterions compare well with previously
reported metal complexes featuring κ2-P,N or κ2-P,C indenide
ligands,6 including those reported herein (Vide supra); the
contracted P1-C3 and P2-C2 distances suggest that nonzwit-
terionic resonance contributors featuring PdC linkages and a
formal negative charge on P1 and/or P2 should be considered
in describing the electronic structure of these complexes.15 In
contrast to the nearly identical Ru-P distances that are found
in 4 · PPh3, the Ru-P1 linkage in each of 12 and 13 is
significantly longer than the corresponding Ru-P2 distance. We
are unsure as to whether the source of such differing Ru-P
bond lengths is primarily steric or electronic in nature. However,
the observation that structurally related Ru zwitterions supported
by κ2-3-PiPr2-2-NMe2-indenide do not exhibit contracted Ru-N
or N-Cind linkages6b,d may foreshadow important differences
in the behavior of the carbanion unit in structurally related
classes of zwitterionic complexes featuring κ2-P,N- and κ2-P,P-
indenide ancillary ligands. In light of the desirable bond
activation behavior exhibited by cationic Cp*Ru(κ2-P,P) spe-
cies,8 as well as alternative late metal zwitterions developed by
Peters and co-workers24 that feature [κ2-Ph2B(CH2PR2)2]-
ancillary ligands, we are currently in the process of establishing
rational synthetic routes to substituted indenes that can serve
(23) 31P{1H} NMR data for this intermediate (C6D6): δ 76.0 (d, JPP
35.3 Hz), 40.7 (d, JPP ) 35.3 Hz).
(24) Selected examples: (a) Lu, C. C.; Peters, J. C J. Am. Chem. Soc.
2004, 126, 15818. (b) Thomas, J. C.; Peters, J. C. J. Am. Chem. Soc. 2003,
125, 8870. (c) Betley, T. A.; Peters, J. C. Angew. Chem., Int. Ed. 2003, 42,
2385.
(25) For a review of conceptually related transition metal-mediated
P-C/X exchange at bound phosphine ligands, see: Macgregor, S. A. Chem.
Soc. ReV. 2007, 36, 67.
)

Indenyl Hemilability
Organometallics, Vol. 27, No. 23, 2008 6293
three repeated freeze-pump-thaw cycles and then dried over 4 Å
molecular sieves for 24 h prior to use. PH2Ph (Aldrich) and PHPh2
(Alpha Aesar) were stored over 4 Å molecular sieves for 24 h prior
to use. Aniline, 2,6-dimethylaniline, piperidine, and pyrrole (all
Aldrich) were degassed by using several freeze-pump-thaw cycles
and stored over 4 Å molecular sieves for 24 h prior to use. NH3
(0.5 M in dioxane, Aldrich) was used as received. All other
commercial reagents were obtained from Aldrich and were used
as received, with the exception that PPh3, NaN(SiMe3)2, and
4-dimethylaminopyridine (DMAP) were dried in Vacuo for 24 h
prior to use. Unless otherwise stated NMR characterization data
were collected at 300 K on a Bruker AV-500 spectrometer operating
at 500.1 (1H), 125.8 (13C), 99.4 (29Si), and 202.5 (31P) MHz with
chemical shifts reported in parts per million downfield of SiMe4
Summary and Conclusions
In the pursuit of new classes of highly reactive, yet isolable,
platinum-group metal complexes that are capable of mediating
challenging substrate transformations, the identification of novel
ancillary ligands whose dynamic coordination behavior renders
the associated metal fragments operationally unsaturated26
represents an important challenge. In this report we have
demonstrated that the isolable 18-electron complex 3 provides
access to the reactive, coordinatively unsaturated zwitterion 4
by way of an unprecedented and reversible Ru-C(sp3) bond
cleavage process, as evinced by data obtained from dynamic
NMR investigations and reactivity studies. The apparent reactiv-
ity of 4 with E-H containing substrates (E ) H, C, N, O, and
Si) can be rationalized in terms of net cooperative substrate
activation involving the Lewis acidic metal fragment and the
Lewis basic indenide unit in 4. Furthermore, in exploring the
reactivity of the intermediate 4 with PHPh2 and PH2Ph, an
unusual ancillary ligand rearrangement involving the net me-
tathesis of P-H and C-N bonds was observed, resulting in
the formation of zwitterionic Cp*Ru(dCH(NHMe))(κ2-P,P)
complexes (12 and 13) that feature the first examples of κ2-
P,P-indenide ligation. We anticipate that the unusual ancillary
ligand design featured in 3 will serve as a general strategy for
unveiling reactive, coordinatively unsaturated platinum-group
metal zwitterions in situ by way of indenyl hemilabilityswhat
is perhaps the first example of a more general phenomenon
(carbanion hemilability) that may be exploited in appropriately
designed ligand systems. In this regard, we are currently
evaluating the utility of this and related ligation strategies in
combination with other platinum-group metals, in an effort to
establish new classes of complexes for use in promoting a range
of demanding stoichiometric and catalytic substrate transforma-
tions enabled by metal-ligand cooperative behavior. We will
disclose our progress in these efforts in future reports.
(for 1H, 13C, and 29Si), or 85% H3PO4 in D2O (for 31P). 1H and 13
C
NMR chemical shift assignments are given on the basis of data
obtained from 13C-DEPT, 1H-1H COSY, 1H-13C HSQC, and
1H-13C HMBC NMR experiments. EXSY spectra of 3 were
acquired at 300 K using a mixing time of 0.5 s. 29Si NMR chemical
shift assignments and coupling constant data are given on the basis
of data obtained from 1H-29Si HMBC/HMQC and 1H-coupled
1
1H-29Si HMQC experiments. H-15N HMQC experiments were
used to confirm N-H assignments. IR data were collected on a
Bruker VECTOR 22 FT-IR instrument. Elemental analyses were
performed either by Canadian Microanalytical Service Ltd., Delta,
British Columbia, Canada or by Desert Analytics, Tucson, AZ.
Synthesis of 2a. To a glass vial containing freshly prepared 1
(0.15 g, 0.29 mmol) was added CH2Cl2 (5 mL). The vial was sealed
with a PTFE-lined cap and magnetic stirring was initiated. Over
the course of 1 h, the initial red-orange solution gradually darkened
to deep red and then to dark brown. After 6 h, 31P NMR data
collected on an aliquot of this solution indicated clean conversion
to 2a. The CH2Cl2 solvent and other volatile materials were removed
in Vacuo, yielding an oily brown solid. The solid was triturated
with pentane (1.5 mL) and the product was dried in Vacuo to yield
2a as an analytically pure, orange-brown powder (0.15 g, 0.28
mmol, 96%). Anal. calcd for C27H39PNRuCl: C 59.47; H 7.22; N
1
Experimental Section
2.57. Found: C 59.16; H 7.21; N 2.57. H NMR (C6D6): δ 12.60
(d, J ) 2.5 Hz, 1H, RudCH), 7.68 (d, 3JHH ) 8.0 Hz, 1H, C4-H
or C7-H), 7.27 (t, 3JHH ) 7.5 Hz, 1H, C5-H or C6-H), 7.19-7.12
(m, 2H, aryl Hs), 3.28 (m, 1H, P(CHMeaMeb)), 2.92 (br. s, 2H,
C(Ha)(Hb)), 2.85 (s, 3H, NMe), 1.77 (d of d, 3JPH ) 10.5 Hz, 3JHH
) 7.0 Hz, 3H, P(CHMeaMeb)), 1.69 (s, 15H, C5Me5), 1.56 (m, 1H,
P(CHMecMed)), 1.22 (d of d, 3JPH ) 19.0 Hz, 3JHH ) 7.0 Hz, 3H,
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 d and then evacuated for 24 h prior to use. The
nondeuterated solvents dichloromethane, diethyl ether, benzene, and
pentane were deoxygenated and dried by sparging with dinitrogen
gas, followed by passage through a double-column solvent purifica-
tion system purchased from mBraun Inc. Dichloromethane and
diethyl ether were 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
3
3
P(CHMeaMeb)), 1.03 (d of d, JPH ) 11.5 Hz, JHH ) 7.0 Hz, 3H,
3
3
P(CHMecMed)), 0.76 (d of d, JPH ) 15.5 Hz, JHH ) 7.0 Hz, 3H,
P(CHMecMed)); 13C{1H} (C6D6): δ 246.9 (d, JPC ) 18.0 Hz,
2
RudC), 159.4 (d, 2JPC ) 10.4 Hz, C2), 147.2 (C3a or C7a), 137.5
(d, JPC ) 6.2 Hz, C7a or C3a), 126.8 (C5 or C6), 123.0-122.9 (m,
2 aryl CHs), 122.0 (C4 or C7), 108.0 (m, C3), 98.1 (C5Me5), 49.3
3
1
(NMe), 40.6 (d, JPC ) 6.3 Hz, C1), 31.4 (d, JPC ) 24.4 Hz,
P(CHMecMed)), 26.5 (d, JPC ) 26.3 Hz, P(CHMeaMeb)), 21.4
1
(P(CHMeaMeb)), 19.0 (d, 2JPC ) 10.1 Hz, P(CHMeaMeb)), 18.7-18.5
(m, P(CHMecMed)), 10.2 (C5Me5); 31P{1H} NMR (C6D6): δ 59.0.
Synthesis of 2b. To a glass vial containing a magnetically stirred
solution of freshly prepared 2a (0.098 g, 0.18 mmol) in C6H6 (5
mL), was added NEt3 (2 mL). The vial was then sealed with a
PTFE-lined cap and the solution was magnetically stirred for 1
week. 31P NMR data collected on an aliquot of this solution
indicated quantitative conversion to 2b. The C6H6 solvent and other
volatile materials were then removed in Vacuo, yielding a dark red-
brown solid. The solid was then washed with cold pentane (2 ×
1.5 mL, precooled to -35 °C) and the product was then dried in
Vacuo to yield 2b as an analytically pure, reddish-brown powder
(0.089 g, 0.16 mmol, 91%). Anal. calcd for C27H39PNRuCl: C
59.47; H 7.22; N 2.57. Found: C 59.26; H 7.60; N 2.53. 1H NMR
sieves. Compound
1 was prepared employing literature
procedures.6d Hydrogen (99.999%, UHP grade) and carbon mon-
oxide gases (99.5%, chemically pure grade) were obtained from
Air Liquide and were used as received. Purification of triethylamine
was achieved by stirring over KOH for 7 d, followed by distillation;
the distilled triethylamine was then refluxed over CaH2 for 3 d under
dinitrogen, followed by distillation. Purification of iPrOH (Aldrich,
anhydrous 99.5%) was achieved by sparging with dinitrogen over
a period of 0.25 h followed by storage over 4 Å molecular sieves
i
(ca. 10 g/100 mL PrOH) for a minimum of 24 h. C6D6 (Aldrich),
Ph2SiH2 (Aldrich), and PhSiH3 (Strem) were degassed by using
(26) Johnson, T. J.; Folting, K.; Streib, W. E.; Martin, J. D.; Huffman,
J. C.; Jackson, S. A.; Eisenstein, O.; Caulton, K. G. Inorg. Chem. 1995,
34, 488.
3
(C6D6): δ 12.29 (s, 1H, RudCH), 7.52 (d, JHH ) 8.0 Hz, 1H,

6294 Organometallics, Vol. 27, No. 23, 2008
Rankin et al.
3
C4-H or C7-H), 7.35 (d, JHH ) 7.5 Hz, 1H, C7-H or C4-H),
yellow solid. The residue was triturated with pentane (2 × 1.5
mL), and the pentane was removed in Vacuo to yield 4 · DMAP
as an analytically pure, yellow powder (0.097 g, 0.15 mmol,
95%). Anal. calcd for C34H48PN3Ru: C 64.72; H 7.67; N 6.66.
7.25 (t,3 JHH ) 7.5 Hz, 1H, C5-H or C6-H), 7.12 (m, 1H, C6-H
2
or C5-H), 6.59 (d, JPH ) 15.5 Hz, 1H, C1-H), 5.94 (s, 1H,
C3-H), 3.17 (m, 1H, P(CHMeaMeb)), 2.95 (s, 3H, NMe), 1.75 (d
of d, 3JPH ) 15.0 Hz, 3JHH ) 7.0 Hz, 3H, P(CHMeaMeb)), 1.71 (s,
Found: C 64.76; H 7.72; N 6.65. H NMR (C6D6): δ 11.71 (s,
1
3
3
15H, C5Me5), 1.21 (m, 1H, P(CHMecMed)), 0.94 (d of d, JPH
)
)
)
1H, RudCH), 8.03 (d, JHH ) 7.5 Hz, 1H, C4-H or C7-H),
3
3
3
3
15.0 Hz, JHH ) 7.0 Hz, 3H, P(CHMeaMeb)), 0.54 (d of d, JPH
7.86 (d, JHH ) 8.5 Hz, 1H, C7-H or C4-H), 7.73 (d, JHH )
3
3
15.0 Hz, JHH ) 7.5 Hz, 3H, P(CHMecMed)), 0.36 (d of d, JPH
7.0 Hz, 2H, DMAP-aryl Hs), 7.26 (t, 3JHH ) 7.0 Hz, 1H, C5-H
10.5 Hz, JHH ) 7.5 Hz, 3H, P(CHMecMed)); 13C{1H} (C6D6): δ
244.3 (d, 2JPC ) 19.8 Hz, RudC), 152.1 (C2), 143.4 (d, JPC ) 2.0
Hz, C3a or C7a), 141.0 (d, JPC ) 8.8 Hz, C7a or C3a), 126.3 (C5
or C6), 124.3 (C4 or C7), 123.0 (C6 or C5), 120.4 (C7 or C4),
or C6-H), 7.21 (t, JHH ) 7.5 Hz, 1H, C6-H or C5-H), 6.74
3
3
(d, J ) 4.0 Hz, 1H, C1-H), 5.40 (d, 3JHH ) 6.5 Hz, 2H, DMAP-
aryl Hs), 3.80 (s, 3H, NMe), 3.76 (m, 1H, P(CHMeaMeb)), 1.74
(s, 6H, DMAP NMe2), 1.71 (m, 1H, P(CHMecMed)), 1.62 (s,
15H, C5Me5), 1.30-1.23 (m, 6H, P(CHMeaMeb) and P(CHMec-
3
108.6 (d, JPC ) 2.3 Hz, C3), 96.0 (C5Me5), 49.2 (NMe), 45.6 (d,
1JPC ) 7.9 Hz, C1), 27.1-26.8 (m, P(CHMecMed) and P(CH-
Med)), 0.89-0.84 (apparent d of d, JPH ) 14.5 Hz, JHH ) 7.0
3
3
MeaMeb)), 21.0 (d, 2JPC ) 3.3 Hz, P(CHMeaMeb)), 18.5 (d, 2JPC
)
Hz, 6H, P(CHMeaMeb) and P(CHMecMed)); 13C{1H} (C6D6): δ
2
2
3.3 Hz, P(CHMecMed)), 17.5 (d, JPC ) 4.5 Hz, P(CHMeaMeb)),
16.8 (d, 2JPC ) 6.4 Hz, P(CHMecMed)), 10.4 (C5Me5); 31P{1H} NMR
(C6D6): δ 93.0.
233.0 (d, JPC ) 20.3 Hz, RudC), 156.4 (2 DMAP-aryl CHs),
2
152.4 (DMAP-aryl C), 145.0 (d, JPC ) 15.1 Hz, C2), 133.5 (d,
JPC ) 9.8 Hz, C3a or C7a), 133.2 (C7a or C3a), 119.9 (C4 or
Synthesis of 3. To a glass vial containing a magnetically stirred
solution of 2a (0.16 g, 0.29 mmol) in benzene (5 mL) was added
solid NaN(SiMe3)2 (0.054 g, 0.29 mmol) all at once; alternatively,
2b can be used in place of 2a. 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 dark brown to
dark red. After 45 min, 31P NMR data collected on an aliquot of
this crude reaction mixture indicated the quantitative formation of
3. The solution was filtered through Celite and the benzene solvent
and other volatile materials were removed in Vacuo, yielding an
oily dark red solid. The residue was treated with pentane (2 × 2
mL), after which the dark-red supernatant solution was carefully
removed via a Pasteur pipet, leaving a red solid. The pentane
solution was stored at -35 °C in order to induce precipitation. After
12 h, a red-orange 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 3 as an analytically pure, red-orange powder
(0.12 g, 0.24 mmol, 81%). Anal. calcd for C27H38PNRu: C 63.74;
H 7.53; N 2.75. Found: C 63.67; H 7.17; N 2.52. 1H NMR (C6D6):
C7), 119.4 (C7 or C4), 117.4 (C5 or C6), 115.3 (C6 or C5),
3
106.4 (2 DMAP-aryl CHs), 93.5 (C5Me5), 92.6 (d, JPC ) 6.5
Hz, C1), 71.1 (d, 1JPC ) 59.0 Hz, C3), 53.0 (NMe), 37.8 (DMAP
1
1
NMe2), 31.2 (d, JPC ) 25.5 Hz, P(CHMecMed)), 24.3 (d, JPC
) 27.9 Hz, P(CHMeaMeb)), 19.7 (P(CHMeaMeb) or P(CHMec-
Med)), 19.3 (d, 2JPC ) 7.8 Hz, P(CHMeaMeb) or P(CHMecMed)),
2
18.8 (d, JPC ) 4.2 Hz, P(CHMeaMed) or P(CHMeaMeb)), 18.6
2
(d, JPC ) 6.0 Hz, P(CHMecMed) or P(CHMeaMeb)), 10.5
(C5Me5); 31P{1H} NMR (C6D6): δ 55.3. Slow evaporation of a
diethyl ether solution of 4 · DMAP produced a crystal suitable
for single-crystal X-ray diffraction analysis.
Synthesis of 4 · CO. Within a glovebox, a J. Young NMR tube
was charged with 3 (0.015 g, 0.030 mmol) and 0.8 mL of C6D6.
The tube was sealed and the solution was mixed by inversion of
the tube several times. The resulting dark red 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 lighten gradually in color to red-orange over the course
1
of several min. After 30 min, 31P and H NMR data collected on
this reaction mixture indicated quantitative conversion to 4 · CO.
Upon removal of solvent and other volatile materials in Vacuo,
followed by trituration with pentane (2 × 1.5 mL), 4 · CO was
isolated as an analytically pure, bright-yellow powder (0.015 g,
0.028 mmol, 96%). Anal. calcd for C28H38PNORu: C 62.65; H 7.14;
3
δ 11.45 (s, 1H, RudCH), 7.56 (d, JHH ) 7.5 Hz, 1H, C4-H or
C7-H), 7.29 (m, 1H, C5-H or C6-H), 7.22 (m, 1H, C6-H or
C5-H), 7.14 (m, 1H, C7-H or C4-H), 6.19 (s, 1H, C3-H), 2.84
(d, J ) 2.0 Hz, 3H, NMe), 2.36 (m, 1H, P(CHMeaMeb)), 1.89-1.81
(m, 16H, C5Me5 and P(CHMecMed)), 1.18 (d of d, 3JPH ) 18.5 Hz,
3JHH ) 7.0 Hz, 3H, P(CHMeaMeb)), 1.02 (d of d, 3JPH ) 18.5 Hz,
3JHH ) 7.0 Hz, 3H, P(CHMecMed)), 0.98-0.94 (m, 6H, P(CH-
1
N 2.61. Found: C 62.26; H 7.04; N 2.56. H NMR (C6D6): δ 9.95
3
(s, 1H, RudCH), 8.02 (d, JHH ) 7.5 Hz, 1H, C4-H or C7-H),
7.92 (d, 3JHH ) 8.5 Hz, 1H, C7-H or C4-H), 7.40 (m, 1H, C5-H
or C6-H), 7.31 (m, 1H, C6-H or C5-H), 6.61 (d, J ) 3.5 Hz,
1H, C1-H), 3.69 (m, 1H, P(CHMeaMeb)), 3.32 (s, 3H, NMe), 1.56
(d, J ) 1.0 Hz, 15H, C5Me5), 1.52 (m, 1H, P(CHMecMed)), 1.32
(d of d, 3JPH ) 17.0 Hz, 3JHH ) 7.0 Hz, 3H, P(CHMeaMeb)), 1.10
MeaMeb) and P(CHMecMed)); 13C{1H} (C6D6): δ 246.7 (d, 2JPC
12.8 Hz, RudC), 166.4 (C2), 148.9 (C3a or C7a), 144.4 (d, JPC
)
)
3.5 Hz, C7a or C3a), 122.1 (C5 or C6), 121.1 (C4 or C7), 120.5
(C6 or C5), 120.4 (C7 or C4), 101.8 (C3), 90.7 (C5Me5), 40.8
1
1
3
3
(NMe), 30.5 (d, JPC ) 21.1 Hz, P(CHMeaMeb)), 25.2 (d, JPC
)
(d of d, JPH ) 12.0 Hz, JHH ) 7.0 Hz, 3H, P(CHMecMed)), 0.89
3 3
2
14.3 Hz, C1), 23.1 (d, JPC ) 7.7 Hz, P(CHMecMed)), 21.4-21.2
(d of d, JPH ) 17.0 Hz, JHH ) 7.0 Hz, 3H, P(CHMeaMeb)), 0.62
3 3
2
(m, P(CHMecMed) and P(CHMeaMed)), 19.6 (d, JPC ) 8.3 Hz,
(d of d, JPH ) 17.0 Hz, JHH ) 7.0 Hz, 3H, P(CHMecMed));
2
2
P(CHMeaMeb)), 18.8 (d, JPC ) 8.1 Hz, P(CHMeaMeb)), 11.5
13C{1H} (C6D6): δ 221.9 (d, JPC ) 15.9 Hz, RudC), 204.2 (d,
(C5Me5); 31P{1H} NMR (C6D6): δ 78.8. Slow evaporation of a C6D6
solution of 3 produced a crystal suitable for single-crystal X-ray
diffraction analysis.
2JPC ) 17.7 Hz, Ru-CO), 144.1 (d, 2JPC ) 15.2 Hz, C2), 133.0 (d,
JPC ) 11.2 Hz, C3a or C7a), 132.5 (C7a or C3a), 121.1 (C4 or
C7), 118.9 (2 aryl CHs), 116.5 (C5 or C6), 98.4 (C5Me5), 96.7 (d,
1
Synthesis of 4 · DMAP. To a glass vial containing a magneti-
cally stirred solution of 3 (0.082 g, 0.16 mmol) in benzene (6
mL) was added solid DMAP (0.020 g, 0.16 mmol) all at once.
An immediate lightening of the solution from dark red to a lighter
red was observed upon the addition of DMAP. The vial was
sealed with a PTFE-lined cap, and the solution was stirred for
45 min, after which time the solution was orange in color. 31P
NMR data collected on an aliquot of this solution indicated
quantitative conversion to 4 · DMAP. The solvent and other
volatile materials were removed in Vacuo, yielding an oily dark
3JPC ) 7.0 Hz, C1), 72.8 (d, JPC ) 72.3 Hz, C3), 53.4 (NMe),
30.2 (d, 1JPC ) 22.8 Hz, P(CHMecMed)), 24.6 (d, 1JPC ) 36.7 Hz,
P(CHMeaMeb)), 19.8 (P(CHMeaMeb)), 17.9-17.8 (m, P(CH-
MeaMeb) and P(CHMecMed)), 10.2 (C5Me5); 31P{1H} NMR (C6D6):
δ 50.7. FTIR (CsI; cm-1) ν(CO): 1940.
Synthesis of 4 · NH3. To a glass vial containing a mixture of 3
(0.099 g, 0.20 mmol) in benzene (3 mL) was added NH3 (0.5 M in
dioxane, 3.9 mL, 2.0 mmol) via Eppendorf micropipette, which
resulted in the formation of a dark red-orange solution. The vial
was then sealed with a PTFE-lined cap and stirred magnetically

Indenyl Hemilability
Organometallics, Vol. 27, No. 23, 2008 6295
for 48 h, after which the solution was brown-orange in color.
Analysis of 31P NMR data collected on an aliquot of this solution
indicated quantitative conversion to 4 · NH3. After removal of
volatile materials in Vacuo, the residue was triturated with pentane
(1.5 mL), and then washed with pentane (2 × 1.5 mL). Residual
volatile materials were then removed in Vacuo, and 4 · NH3 was
isolated as a analytically pure, brown-yellow powder (0.077 g, 0.15
mmol, 75%). Anal. calcd for C27H41PN2Ru: C 61.67; H 7.87; N
micropipette. The addition caused an immediate color change of
the solution from dark red to orange-brown. After 30 min, 31P NMR
data collected on an aliquot of this solution indicated the presence
of a mixture of 4 · NC8H11 and 3 (ca. 2:1 ratio). In an effort to
induce further conversion of 3 to 4 · NC8H11, the solution was
reduced in volume to ca. 2 mL in Vacuo. 31P NMR data collected
on the resulting concentrated solution indicated the presence of only
one phosphorus-containing product in solution (58.9 ppm,
4 · NC8H11). In order to induce precipitation of 4 · NC8H11, pentane
(4 mL) was added to the solution, followed by storage of the
solution at -35 °C. After 48 h, an orange-brown solid was isolated
(0.055 g). Upon dissolution of this solid (0.022 g) in C6D6 (0.8
mL), a mixture of 4 · NC8H11:3 (ca. 1:4) was detected by use of
31P NMR methods; as well, significant amounts of free 2,6-
1
5.33. Found: C 61.97; H 7.71; N 5.39. H NMR (C6D6): δ 11.27
(d, J ) 1.0 Hz, 1H, RudCH), 7.95 (d, 3JHH ) 8.0 Hz, 1H, C4-H
or C7-H), 7.90 (d, 3JHH ) 8.5 Hz, 1H, C7-H or C4-H), 7.34 (t,
3JHH ) 7.0 Hz, 1H, C5-H or C6-H), 7.23 (t, 3JHH ) 7.0 Hz, 1H,
C6-H or C5-H), 6.52 (d, J ) 3.5 Hz, 1H, C1-H), 3.70 (m, 1H,
P(CHMeaMeb)), 3.47 (s, 3H, NMe), 1.54 (m, 1H, P(CHMecMed)),
1.47 (s, 15H, C5Me5), 1.13 (d of d, 3JPH ) 11.0 Hz, 3JHH ) 6.5 Hz,
1
dimethylaniline were detected in the broadened H NMR spectra
3
3
3H, P(CHMecMed)), 1.04 (d of d, JPH ) 15.0 Hz, JHH ) 7.0 Hz,
3H, P(CHMeaMeb)), 0.86-0.79 (m, 6H, P(CHMeaMeb) and P(CH-
MecMed)), 0.51 (br. s, 3H, NH3); 13C{1H} (C6D6): δ 234.3 (d, 2JPC
) 19.4 Hz, RudC), 144.4 (d, 2JPC ) 15.4 Hz, C2), 134.0 (C3a or
of this solution. Efforts to isolate 4 · NC8H11 in analytically pure
form were hampered by the dissociation of 2,6-dimethylaniline from
4 · NC8H11; as such we are unable to provide a proper yield
determination, as well as comprehensive spectroscopic characteriza-
tion data for this adduct. For characterization purposes, a solution
of 3 (0.023 g, 0.045 mmol) in C6D6 (0.8 mL) was treated with a
large excess of 2,6-dimethylaniline (0.20 mL, 1.6 mmol, ca. 36
equiv). The NMR spectra obtained on the resulting solution featured
broadened signals, and exchange between free and bound amine
precluded the definitive assignment of signals attributable to the
coordinated 2,6-dimethylaniline ligand in 4 · NC8H11. Nonetheless,
assignments of the other portions of 4 · NC8H11 could be made.
C7a), 133.4 (d, JPC ) 9.2 Hz, C7a or C3a), 120.2 (C4 or C7), 118.3
3
(C7 or C4), 118.0 (C5 or C6), 115.8 (C6 or C5), 94.2 (d, JPC
)
1
6.2 Hz, C1), 91.0 (C5Me5), 68.6 (d, JPC ) 55.5 Hz, C3), 52.2
1
1
(NMe), 29.5 (d, JPC ) 25.5 Hz, P(CHMecMed)), 23.7 (d, JPC
)
28.1 Hz, P(CHMeaMeb)), 19.4 (d, 2JPC ) 5.0 Hz, P(CHMeaMeb) or
2
P(CHMecMed)), 18.8 (d, JPC ) 4.9 Hz, P(CHMecMed) or P(CH-
MeaMeb)), 17.9 (d, 2JPC ) 5.7 Hz, P(CHMeaMeb)), 17.3 (d, 2JPC
)
6.0 Hz, P(CHMecMed)), 10.4 (C5Me5); 31P{1H} NMR (C6D6): δ
63.5.
1
Data for 4 · NC8H11: H NMR (C6D6): δ 11.59 (s, 1H, RudCH),
Synthesis of 4 · NC5H11. Piperidine (NC5H11, 0.10 mL, 1.01
mmol) was added via an Eppendorf micropipette to a glass vial
containing a solution of 3 (0.082 g, 0.16 mmol) in benzene (6 mL),
which resulted in a color change of the solution from dark red to
brown-orange. The vial was then sealed with a PTFE-lined cap
and mixed by inversion several times. After 30 min, 31P NMR data
collected on an aliquot of this solution indicated the quantitative
formation of 4 · NC5H11. After removal of volatile materials in
Vacuo, the residue was triturated with pentane (1.5 mL), and then
washed with pentane (2 × 1.5 mL). Residual volatile materials were
then removed in Vacuo, which left 4 · NC5H11 as an analytically
pure, yellow-orange powder (0.078 g, 0.13 mmol, 82%). Anal. calcd
for C32H49PN2Ru: C 64.71; H 8.32; N 4.72. Found: C 64.79; H
7.83 (br. m, 1H, aryl-H), 7.30 (br. t, 3JHH ) 7.0 Hz, 1H, C5-H or
C6-H), 7.15 (m, 1H, aryl-H), 7.04 (br. d, 3JHH ) 7.0 Hz, 1H, C4-H
or C7-H), 6.45 (br. s, 1H, C1-H), 3.75 (br. m, 1H, P(CHMeaMeb)),
3.48 (br. s, 3H, NMe), 1.65 (br. m, 1H, P(CHMecMed)), 1.33-1.21
(br. m, 18H, C5Me5 and P(CHMeaMeb)), 1.14-1.04 (br. m, 6H,
3
P(CHMeaMeb) and P(CHMecMed)), 0.86 (br. d of d, JPH ) 17.5
3
Hz, JHH ) 7.0 Hz, 3H, P(CHMecMed)); 13C{1H} (C6D6): δ 234.5
(br. m, RudC), 120.0 (aryl-CH), 117.9 (C4 or C7), 117.3 (C5 or
C6), 115.1 (aryl-CH), 93.5 (m, C1), 91.5 (C5Me5), 52.2 (NMe),
30.6 (m, P(CHMecMed)), 28.0 (m, P(CHMeaMeb)), 19.8 (P(CH-
MeaMeb)), 18.2 (P(CHMecMed)), 17.7 (P(CHMeaMeb)), 16.4 (P(CH-
MecMed)), 10.2 (C5Me5); 31P{1H} NMR (C6D6): δ 58.9. A crystal
of 4 · NC8H11(2.5NC8H11) suitable for X-ray diffraction analysis was
grown at -35 °C from a concentrated mixture in pentane/2,6-
dimethylaniline (ca. 4:1) of the orange-brown solid isolated as
above.
1
8.07; N 4.31. H NMR (C6D6, pip ) piperidine): δ 11.32 (d, J )
3
1.5 Hz, 1H, RudCH), 8.02 (d, JHH ) 8.0 Hz, 1H, C4-H or
3
C7-H), 7.87 (d, JHH ) 8.0 Hz, 1H, C7-H or C4-H), 7.40 (m,
3
1H, C5-H or C6-H), 7.26 (t, JHH ) 7.0 Hz, 1H, C6-H or
Synthesis of 4 · PPh3. To a glass vial containing a magnetically
stirred solution of 3 (0.072 g, 0.14 mmol) in benzene (5 mL) was
added PPh3 (0.037 g, 0.14 mmol) all at once. An immediate
lightening of the solution from dark red to a lighter red was observed
upon the addition of PPh3. The vial was sealed with a PTFE-lined
cap, and the solution was stirred for 15 min, after which time the
solution was red-orange in color. 31P NMR data collected on an
aliquot of this solution indicated quantitative conversion to 4 · PPh3.
The solvent and other volatile materials were removed in Vacuo,
affording an oily orange-yellow solid. The residue was triturated
with pentane (2 × 3 mL), and the pentane was removed in Vacuo
to yield 4 · PPh3 as an analytically pure, bright orange-yellow
powder (0.11 g, 0.14 mmol, 96%). Anal. calcd for C45H53P2NRu:
C 70.09; H 6.93; N 1.82. Found: C 69.98; H 6.87; N 1.73.1H NMR
C5-H), 6.54 (d, J ) 3.5 Hz, 1H, C1-H), 3.72 (m, 1H, P(CH-
MeaMeb)), 3.62 (apparent br. t, J ) 11.5 Hz, 1H, N-H), 3.38 (s,
3H, NMe), 2.81 (d, J ) 13.0 Hz, 1H, pip-CH), 2.37 (d, J ) 12.5
Hz, 1H, pip-CH), 1.97 (m, 1H, pip-CH), 1.70 (m, 1H, pip-CH),
1.60-1.54 (m, 16H, C5Me5 and P(CHMecMed)), 1.32 (d of d, 3JPH
3
) 14.5 Hz, JHH ) 7.0 Hz, 3H, P(CHMeaMeb)), 1.14-1.08 (m,
6H, P(CHMeaMeb) and P(CHMecMed)), 0.92-0.84 (m, 5H, P(CH-
MecMed) and 2 pip-CHs), 0.74-0.67 (m, 3H, pip-CHs), 0.47 (m,
1H, pip-CH); 13C{1H} (C6D6): δ 235.2 (d, 2JPC ) 20.3 Hz, RudC),
2
144.1 (d, JPC ) 15.0 Hz, C2), 134.3 (C3a or C7a), 133.7 (d, JPC
) 9.3 Hz, C7a or C3a), 120.4 (C4 or C7), 118.5 (C7 or C4), 118.3
3
(C5 or C6), 116.1 (C6 or C5), 94.7 (d, JPC ) 6.0 Hz, C1), 92.1
(C5Me5), 68.3 (d, 1JPC ) 53.0 Hz, C3), 59.1 (pip-C), 57.6 (pip-C),
1
3
51.8 (NMe), 30.6 (d, JPC ) 25.9 Hz, P(CHMecMed)), 28.6 (pip-
(C6D6): δ 11.13 (s, 1H, RudCH), 7.84 (d, JHH ) 8.0 Hz, 1H,
1
3
C), 28.3 (pip-C), 23.9 (pip-C), 23.5 (d, JPC ) 26.4 Hz, P(CH-
C4-H or C7-H), 7.67 (d, JHH ) 8.0 Hz, 1H, C7-H or C4-H),
MeaMeb)), 21.0 (d, 2JPC ) 4.3 Hz, P(CHMeaMeb)), 19.4 (d, 2JPC
)
7.56-7.40 (br. m, 3H, P-aryl Hs), 7.29 (m, 1H, C5-H or C6-H),
7.24 (m, 1H, C6-H or C5-H), 7.08-6.92 (br. m, 6H, P-aryl Hs),
6.71-6.60 (br. m, 3H, P-aryl Hs), 6.43-6.32 (br. m, 3H, P-aryl
Hs), 5.71 (d, J ) 3.5 Hz, 1H, C1-H), 3.54 (m, 1H, P(CHMeaMeb)),
3.38 (s, 3H, NMe), 1.84 (m, 1H, P(CHMecMed)), 1.41 (s, 15H,
C5Me5), 1.16-1.08 (m, 6H, P(CHMeaMeb) and P(CHMecMed)),
2
3.4 Hz, P(CHMecMed)), 19.1 (d, JPC ) 5.8 Hz, P(CHMeaMeb) or
2
P(CHMecMed)), 17.6 (d, JPC ) 5.7 Hz, P(CHMecMed) or P(CH-
MeaMeb)), 11.1 (C5Me5); 31P{1H} NMR (C6D6): δ 61.1.
Formation of 4 · NC8H11. To a glass vial containing a solution
of 3 (0.11 g, 0.21 mmol) in benzene (7 mL) was added 2,6-
dimethylaniline (NC8H11, 0.26 mL, 2.1 mmol) via Eppendorf
3
3
0.93 (d of d, JPH ) 15.5 Hz, JHH ) 7.5 Hz, 3H, P(CHMeaMeb)),

6296 Organometallics, Vol. 27, No. 23, 2008
Rankin et al.
3
0.66 (d of d, JPH ) 15.5 Hz, 3JHH ) 7.0 Hz, 3H, P(CHMecMed));
Formation of 5 and Synthesis of 7. To a glass vial containing
a magnetically stirred solution of 3 (0.084 g, 0.17 mmol) in C6H6
(8 mL), was added solid Ph3SiH (0.043 g, 0.17 mmol). The vial
was sealed with a PTFE-lined cap and the solution was stirred
magnetically for three weeks, during which time the progress of
the reaction was monitored by use of NMR methods; a slight
lightening of the solution was observed over this time period. After
a total of 45 min, 31P NMR revealed the presence of ca. 1:1 ratio
of 3 and a new species 5 (54.1 ppm). Diagnostic 1H NMR data for
5 (C6D6): 10.30 (s, 1H, RudCH), 5.72 (d, J ) 4.1 Hz, 1H, C1-H),
13C{1H} (C6D6): δ 227.1 (apparent t, J ) 18.6 Hz, RudC), 143.3
(d, JPC ) 14.8 Hz, C2), 132.8 (d, JPC ) 10.2 Hz, C3a or C7a),
132.1 (C7a or C3a), 128.6-127.8 (br. m, P-aryl CHs), 120.2 (C4
or C7), 119.2 (C7 or C4), 117.6 (C5 or C6), 115.4 (C6 or C5),
97.1 (C5Me5), 94.9 (d, JPC ) 6.4 Hz, C1), 72.5 (d, JPC ) 60.3
Hz, C3), 53.6 (NMe), 33.3 (d, JPC ) 25.2 Hz, P(CHMecMed)),
25.6 (d, JPC ) 30.7 Hz, P(CHMeaMeb)), 20.7 (P(CHMeaMeb)),
2
3
1
1
1
19.7-19.4 (m, P(CHMeaMeb) and P(CHMecMed)), 18.5 (P(CH-
MecMed)), 10.8 (C5Me5); 31P{1H} NMR (C6D6): δ 55.6 (d, JPP
)
2
2
-9.21 (d, JPH ) 24.3 Hz, 1H, Ru-H). After a total of 24 h, 31P
2
28.3 Hz), 51.2 (d, JPP ) 28.3 Hz). Slow evaporation of a C6H6
solution of 4 · PPh3 produced a crystal of 4 · PPh3(C6H6) suitable
for single-crystal X-ray diffraction analysis.
NMR revealed the presence of 3, 5, and 7 in ca. 2:2:1 ratio. A
total reaction time of three weeks was required in order to achieve
quantitative conversion to 7, at which time the solvent and other
volatile materials were removed in Vacuo, yielding an oily yellow
solid. The solid was triturated with pentane (2 × 1.5 mL) and dried
in Vacuo to yield 7 as an analytically pure, yellow powder (0.12 g,
0.15 mmol, 93%). Anal. calcd for C45H54PNSiRu: C 70.27; H 7.08;
N 1.82. Found: C 70.33; H 7.01; N 1.84. 1H NMR (C6D6): δ 12.40
(s, 1H, RudCH), 7.59-7.56 (m, 6H, Si-aryl Hs), 7.34-7.12 (m,
11H, 9 Si-aryl Hs and C4-H and C7-H), 7.09 (t, 3JHH ) 7.5 Hz,
Synthesis of 4 · PHPh2. To a glass vial containing a magnetically
stirred solution of 3 (0.093 g, 0.18 mmol) in benzene (6 mL) was
added PHPh2 (0.032 mL, 0.18 mmol) via Eppendorf micropipette.
An immediate lightening of the solution from dark red to a lighter
red was observed upon the addition of PHPh2. The vial was sealed
with a PTFE-lined cap, and the solution was stirred for 48 h, after
which time the solution was orange in color. 31P NMR data collected
on an aliquot of this solution indicated quantitative conversion to
4 · PHPh2. The solvent and other volatile materials were removed
in Vacuo, affording an oily yellow solid. The residue was triturated
with pentane (2 × 3 mL), and the pentane was removed in Vacuo
to yield 4 · PHPh2 as an analytically pure, bright yellow powder
(0.12 g, 0.17 mmol, 94%). Anal. calcd for C39H49P2NRu: C 67.40;
H 7.11; N 2.02. Found: C 67.30; H 7.16; N 2.13. 1H NMR (C6D6):
3
1H, C5-H or C6-H), 6.91 (t, JHH ) 6.5 Hz, 1H, C6-H or
C5-H), 5.83 (d, J ) 1.5 Hz, 1H, C3-H), 3.62 (d, 2JPH ) 15.5 Hz,
1H, C1-H), 3.37 (s, 3H, NMe), 2.90 (m, 1H, P(CHMeaMeb)),
1.59-1.56 (m, 16H, C5Me5 and P(CHMecMed)), 1.31 (d of d, 3JPH
) 15.0 Hz, 3JHH ) 6.5 Hz, 3H, P(CHMeaMeb)), 0.96 (d of d, 3JPH
3
3
) 17.0 Hz, JHH ) 7.0 Hz, 3H, P(CHMeaMeb)), 0.79 (d of d, JPH
3
3
) 14.0 Hz, JHH ) 7.5 Hz, 3H, P(CHMecMed)), 0.37 (d of d, JPH
) 9.5 Hz, 3JHH ) 7.0 Hz, 3H, P(CHMecMed)); 13C{1H} (C6D6): δ
249.7 (d, 2JPC ) 20.1 Hz, RudC), 153.3 (C2), 142.6 (C3a or C7a),
139.7 (d, JPC ) 9.2 Hz, C7a or C3a), 136.2 (Si-aryl CHs), 133.7
(Si-aryl C), 130.0 (Si-aryl CHs), 128.4 (Si-aryl CHs), 126.3 (C4
or C7), 123.9 (C7 or C4), 123.3 (C5 or C6), 120.2 (C6 or C5),
3
δ 10.21 (s, 1H, RudCH), 8.08 (d, JHH ) 8.0 Hz, 1H, C4-H or
3
C7-H), 7.91 (d, JHH ) 8.5 Hz, 1H, C7-H or C4-H), 7.40 (t,
3JHH ) 7.0 Hz, 1H, C5-H or C6-H), 7.32 (t, 3JHH ) 7.0 Hz, 1H,
C6-H or C5-H), 7.24-6.87 (m, 10H, P-aryl Hs), 6.85 (d of d,
1JPH ) 380.0 Hz, 3JPH ) 13.0 Hz, 1H, P-H), 6.35 (d, J ) 3.5 Hz,
1H, C1-H), 3.65 (m, 1H, P(CHMeaMeb)), 2.94 (s, 3H, NMe), 1.77
1
108.6 (C3), 97.5 (C5Me5), 50.1 (NMe), 44.8 (d, JPC ) 8.7 Hz,
3
(m, 1H, P(CHMecMed)), 1.56 (s, 15H, C5Me5), 1.33 (d of d, JPH
C1), 28.6 (d, 1JPC ) 20.6 Hz, P(CHMecMed)), 26.7 (d, 1JPC ) 22.3
) 14.5 Hz, 3JHH ) 6.5 Hz, 3H, P(CHMeaMeb)), 1.18 (d of d, 3JPH
2
Hz, P(CHMeaMeb)), 20.0 (d, JPC ) 3.6 Hz, P(CHMeaMeb)),
3
3
) 11.5 Hz, JHH ) 7.0 Hz, 3H, P(CHMecMed)), 1.07 (d of d, JPH
2
19.3-19.2 (m, P(CHMecMed)), 17.6 (d, JPC ) 7.9 Hz, P(CH-
3
3
) 17.0 Hz, JHH ) 7.0 Hz, 3H, P(CHMeaMeb)), 0.80 (d of d, JPH
) 16.0 Hz, 3JHH ) 7.0 Hz, 3H, P(CHMecMed)); 13C{1H} (C6D6): δ
229.5 (apparent t, J ) 16.7 Hz, RudC), 142.6 (d, 2JPC ) 14.1 Hz,
C2), 142.2 (C3a or C7a), 138.9 (d, 1JPC ) 52.7 Hz, P-aryl C), 134.3
(d, JPC ) 10.4 Hz, P-aryl CHs), 133.6 (m, C7a or C3a), 129.4 (P-
aryl CH), 128.8 (P-aryl CH), 127.5 (d, JPC ) 9.4 Hz, P-aryl CHs),
120.6 (C4 or C7), 119.3 (C7 or C4), 118.1 (C5 or C6), 115.9 (C6
MeaMeb)), 10.9 (C5Me5); 31P{1H} NMR (C6D6): δ 86.5; 29Si{1H}
NMR (C6D6): δ 30.6 (1H-29Si HMBC).
Formation of 6 and Synthesis of 8. To a glass vial containing
a magnetically stirred solution of 3 (0.092 g, 0.18 mmol) in benzene
(6 mL), was added Ph2SiH2 (0.036 mL, 0.18 mmol) via Eppendorf
micropipette. The vial was sealed with a PTFE-lined cap and the
solution was stirred magnetically for 24 h, during which time the
progress of the reaction was monitored by use of NMR methods.
After 5 min, 31P NMR revealed the conversion of 3 to a mixture of
or C5), 96.2 (C5Me5), 95.0 (d, 3JPC ) 6.5 Hz, C1), 72.5 (d, 1JPC
)
64.8 Hz, C3), 52.5 (NMe), 31.3 (d, 1JPC ) 24.8 Hz, P(CHMecMed)),
1
25.5 (d, JPC ) 31.3 Hz, P(CHMeaMeb)), 19.9 (P(CHMeaMeb)),
1
6 (54.8 ppm) and 8 (ca. 10:1). Diagnostic H NMR data for 6
18.8-18.6 (m, P(CHMeaMeb) and P(CHMecMed)), 18.4 (d, 2JPC
)
(C6D6): 9.68 (s, 1H, RudCH), 5.96 (d, J ) 3.7 Hz, 1H, C1-H),
3.4 Hz, P(CHMecMed)), 10.7 (C5Me5); 31P{1H} NMR (C6D6): δ
2
5.10 (s, 1H, Si-H), -9.90 (d, JPH ) 25.2 Hz, 1H, Ru-H). A
2
2
57.2 (d, JPP ) 34.4 Hz), 33.6 (d, JPP ) 34.4 Hz).
total reaction time of 24 h was required in order to achieve
quantitative conversion to 8, after which time the solvent and other
volatile materials were removed in Vacuo, yielding an oily yellow
solid. The solid was triturated with pentane (2 × 1.5 mL) and the
product was dried in Vacuo to afford 8 as an analytically pure,
yellow powder (0.11 g, 0.16 mmol, 91%). Anal. calcd for
C39H50PNSiRu: C 67.59; H 7.28; N 2.02. Found: C 67.30; H 7.30;
Reaction of 3 with H2. A protocol analogous to that described
for the synthesis of 4 · CO was employed, using H2 in place of
CO. Introduction of an atmosphere of H2 to 3 caused the solution
to lighten gradually in color from dark red to bright orange over
the course of several minutes. After 10 min, 31P and 1H NMR data
collected on this reaction mixture indicated the quantitative conver-
sion of 3 into 1.
1
3
N 2.04. H NMR (C6D6): δ 7.80 (d, JHH ) 7.0 Hz, 2H, Si-aryl
Reaction of 3 with iPrOH. In a glass vial, a solution of 3 (0.023
g, 0.045 mmol) in C6D6 (ca. 1 mL) was treated with PrOH (0.10
3
Hs), 7.47 (d, JHH ) 7.0 Hz, 2H, Si-aryl Hs), 7.28-7.04 (m, 8H,
i
6 Si-aryl Hs and 2 aryl Hs), 6.74 (t, 3JHH ) 7.5 Hz, 1H, C5-H or
C6-H), 6.51 (d,3 JHH ) 7.5 Hz, 1H, C4-H or C7-H), 5.34 (s,
1H, C3-H), 3.76 (d, J ) 6.5 Hz, 1H, Ru-C(H a)(Hb)-N), 3.43 (d,
J ) 7.0 Hz, 1H, Ru-C(Ha)(H b)-N), 2.64 (s, 3H, NMe), 2.36-2.29
(m, 2H, P(CHMeaMeb) and P(CHMecMed)), 1.72 (s, 15H, C5Me5),
1.17 (d of d, 3JPH ) 17.5 Hz, 3JHH ) 7.0 Hz, 3H, P(CHMeaMeb)),
mL, 1.3 mmol, ca. 29 equiv), which resulted in a lightening of the
solution from dark red to red-orange. The solution was then
transferred to an NMR tube and reaction progress was observed
by use of 31P and H NMR methods. After 30 min, quantitative
1
conversion to the previously characterized6d Ru hydridocarbene
allylic isomer of 1 (i.e., 1b) was noted. After 1.5 h, partial
conversion of 1b to 1 was observed, with full isomerization to 1
noted after 24 h.
3
3
0.94 (d of d, JPH ) 15.5 Hz, JHH ) 7.5 Hz, 3H, P(CHMecMed)),
0.81-0.77 (m, 6H, P(CHMeaMeb) and P(CHMecMed)), -9.40 (d,
2JPH ) 22.5 Hz, 1H, Ru-H); 13C{1H} (C6D6): δ 164.2 (d, JPC
)
2

Indenyl Hemilability
Organometallics, Vol. 27, No. 23, 2008 6297
2.9 Hz, C2), 147.1 (d, JPC ) 2.4 Hz, C3a or C7a), 144.1 (d, 3JPC
)
3H, NMe), 1.96 (m, 1H, P(CHMecMed)), 1.71 (s, 15H, C5Me5),
3
3
3
8.2 Hz, Si-aryl C), 142.3 (d, JPC ) 2.3 Hz, Si-aryl C), 137.2 (Si-
aryl CHs), 137.1 (d, JPC ) 7.3 Hz, C7a or C3a), 133.9 (Si-aryl
CHs), 128.4 (Si-aryl CHs), 127.3 (Si-aryl CH), 127.2 (Si-aryl CH),
127.0 (Si-aryl CH), 126.5 (C5 or C6), 126.2 (C4 or C7), 118.0
(C6 or C5), 116.6 (C7 or C4), 94.5 (C5Me5), 92.6 (C3), 63.7 (d,
1.34 (d of d, JPH ) 10.5 Hz, JHH ) 7.0 Hz, 3H, P(CHMecMed)),
3 3
1.18 (d of d, JPH ) 16.0 Hz, JHH ) 7.0 Hz, 3H, P(CHMecMed)),
0.94 (d of d, 3JPH ) 15.0 Hz, 3JHH ) 7.0 Hz, 3H, P(CHMeaMeb)),
3
0.81 (d of d, JPH ) 16.5 Hz, 3JHH ) 7.0 Hz, 3H, P(CHMeaMeb));
2
13C{1H} (C6D6): δ 235.3 (d, JPC ) 13.3 Hz, RudC), 184.3 (d,
2
1JPC ) 6.2 Hz, C1), 43.6 (d, JPC ) 13.0 Hz, Ru-CH2-N), 42.5
2JPC ) 26.2 Hz, C2), 149.7 (N-aryl C), 142.1 (C3a or C7a), 139.4
(d, J ) 8.2 Hz, C7a or C3a), 130.0 (2 aryl CHs), 127.5 (N-aryl
1
1
(NMe), 29.5 (d, JPC ) 6.0 Hz, P(CHMecMed)), 28.8 (d, JPC
)
2
22.6 Hz, P(CHMeaMeb)), 22.9 (d, JPC ) 5.5 Hz, P(CHMecMed)),
19.8 (P(CHMeaMeb)), 19.4 (m, P(CHMecMed)), 18.9 (m, P(CH-
MeaMeb)), 10.7 (C5Me5); 31P{1H} NMR (C6D6): δ 61.1; 29Si{1H}
NMR (C6D6): δ 9.8 (1H-29Si HMBC), 2JSiH ) 21.0 Hz (1H-coupled
1H-29Si HMQC). A crystal of 8 suitable for X-ray diffraction
analysis was grown from a concentrated pentane solution at -35
°C.
CH), 123.8 (N-aryl CH), 123.3 (N-aryl CH), 117.0 (aryl CH), 115.8
1
(2 N-aryl CHs), 115.0 (aryl CH), 94.6 (C5Me5), 88.4 (d, JPC
)
3
43.8 Hz, C3), 45.3 (NMe), 35.2 (d, JPC ) 10.8 Hz, C1), 29.4 (d,
1JPC ) 17.2 Hz, P(CHMecMed)), 24.3 (d, JPC ) 34.3 Hz,
1
2
P(CHMeaMeb)), 20.2 (P(CHMeaMeb)), 19.7 (d, JPC ) 7.2 Hz,
P(CHMecMed)), 19.4-19.2 (m, P(CHMeaMeb) and P(CHMecMed)),
11.1 (C5Me5); 31P{1H} NMR (C6D6): δ 76.2.
Isomerization of 8 to 9. After extended time periods in solution
(0.016 g, 0.8 mL C6D6), 8 was observed by use of 31P NMR to
convert partially to a new phosphorus-containing species, 9 (the
SiPh2H analogue of 7). After one week, the 8:9 ratio was ca. 10:1.
Periodic monitoring of the solution by 31P NMR revealed a ratio
of 8:9 of 1:8 after 5 months. Continued observation found little
change in this ratio up to 8 months. In an effort to accelerate the
transformation of 8 to 9, a solution of 8 (0.018 g, 0.8 mL C6D6)
was heated at 60 °C. However, 9 was observed to decompose to a
variety of phosphorus-containing species under these conditions
within 48 h. Data for 9: 1H NMR (C6D6): δ 11.66 (s, 1H, RudCH),
7.89-7.86 (m, 2H, Si-aryl Hs), 7.50-7.47 (m, 2H, Si-aryl Hs),
7.40 (d, 3JHH ) 7.5 Hz, 1H, C4-H or C7-H), 7.32-7.08 (m, 9H,
3 aryl Hs and 6 Si-aryl Hs), 5.91 (d, J ) 1.0 Hz, 1H, C3-H), 5.75
Synthesis of 11. To a glass vial containing a solution of 3 (0.10
g, 0.20 mmol) in benzene (7 mL) was added pyrrole (0.016 mL,
0.23 mmol) via Eppendorf micropipette. The addition caused an
immediate color change from dark red to a lighter red-orange. After
10 min, analysis of 31P NMR data collected on an aliquot of this
solution indicated quantitative conversion to 11. The mixture was
then dried in Vacuo, followed by trituration with pentane (1.5 mL).
After removal of volatile materials in Vacuo, 11 was isolated as an
analytically pure, reddish-brown powder (0.11 g, 0.19 mmol, 95%).
Anal. calcd for C31H43PN2Ru: C 64.65; H 7.53; N 4.87. Found: C
64.51; H 7.35; N 4.72. 1H NMR (C6D6): δ 12.49 (s, 1H, RudCH),
7.28 (d, 3JHH ) 8.0 Hz, 1H, C4-H or C7-H), 7.23 (d, 3JHH ) 7.5
3
Hz, 1H, C7-H or C4-H), 7.17 (t, JHH ) 7.5 Hz, 1H, C5-H or
C6-H), 7.01 (apparent d of t, J ) 7.5 Hz, J ) 1.0 Hz, 1H, C6-H
or C5-H), 6.85 (br. m, 1H, pyrrole-H), 6.68-6.53 (br. m, 2H,
pyrrole-Hs), 6.11 (br. m, 1H, pyrrole-H), 5.94 (d, J ) 1.5 Hz, 1H,
C3-H), 5.09 (d, 2JPH ) 14.5 Hz, 1H, C1-H), 3.09 (s, 3H, NMe),
2.97 (m, 1H, P(CHMeaMeb)), 1.64 (d, J ) 1.0 Hz, 15H, C5Me5),
1.48 (d of d, 3JPH ) 15.5 Hz, 3JHH ) 7.0 Hz, 3H, P(CHMeaMeb)),
2
(d, J ) 4.5 Hz, 1H, Si-H), 5.49 (d, JPH ) 14.5 Hz, 1H, C1-H),
3.08-3.01 (m, 4H, NMe and P(CHMeaMeb)), 1.69 (s, 15H, C5Me5),
1.51 (m, 1H, P(CHMecMed)), 1.36 (d of d, 3JPH ) 15.5 Hz, 3JHH
7.0 Hz, 3H, P(CHMeaMeb)), 0.91 (d of d, 3JPH ) 16.5 Hz, 3JHH
)
)
)
)
)
3
3
7.0 Hz, 3H, P(CHMecMed)), 0.81 (d of d, JPH ) 15.0 Hz, JHH
3
3
7.5 Hz, 3H, P(CHMeaMeb)), 0.48 (d of d, JPH ) 10.0 Hz, JHH
1.17 (m, 1H, P(CHMecMed)), 0.94 (d of d, 3JPH ) 15.0 Hz, 3JHH
)
)
)
)
)
7.0 Hz, 3H, P(CHMecMed)); 13C{1H} (C6D6): δ 250.8 (d, JPC
7.0 Hz, 3H, P(CHMeaMeb)), 0.50 (d of d, JPH ) 15.0 Hz, JHH
3
3
3
3
17.2 Hz, RudC), 153.0 (C2), 149.8 (Si-aryl C), 145.7 (Si-aryl C),
143.2 (C3a or C7a), 140.2 (d, JPC ) 8.4 Hz, C7a or C3a), 137.6
(Si-aryl CHs), 135.7 (Si-aryl CHs), 127.1 (Si-aryl CH or aryl CH),
126.9 (Si-aryl CH or aryl CH), 126.8 (Si-aryl CH or aryl CH),
126.7 (Si-aryl CH or aryl CH), 126.5 (Si-aryl CH or aryl CH),
124.7 (C4 or C7), 123.3 (Si-aryl CH or aryl CH), 120.4 (Si-aryl
CH or aryl CH), 109.0 (C3), 96.7 (C5Me5), 49.8 (NMe), 44.3 (d,
1JPC ) 9.7 Hz, C1), 29.2 (d, 1JPC ) 18.9 Hz, P(CHMecMed)), 27.0
(d, 1JPC ) 23.5 Hz, P(CHMeaMeb)), 19.4 (m, P(CHMeaMeb)), 19.2
7.5 Hz, 3H, P(CHMecMed)), 0.31 (d of d, JPH ) 10.5 Hz, JHH
7.5 Hz, 3H, P(CHMecMed)); 13C{1H} (C6D6): δ 247.4 (d, JPC
2
20.1 Hz, RudC), 151.7 (C2), 143.5 (C3a or C7a), 140.5 (d, JPC
8.8 Hz, C7a or C3a), 126.7 (C5 or C6), 124.6 (C4 or C7), 123.5
(C6 or C5), 120.7 (C7 or C4), 109.6 (C3), 108.3-108.0 (br. m,
1
pyrrole-CHs), 97.2 (C5Me5), 49.7 (NMe), 45.0 (d, JPC ) 7.3 Hz,
C1), 27.5 (d, 1JPC ) 23.3 Hz, P(CHMecMed)), 26.2 (d, 1JPC ) 17.2
2
Hz, P(CHMeaMeb)), 21.6 (d, JPC ) 4.4 Hz, P(CHMeaMeb)), 19.1
2
(P(CHMecMed)), 18.2 (d, JPC ) 4.9 Hz, P(CHMeaMeb)), 17.1 (d,
2
2
(d, JPC ) 3.3 Hz, P(CHMeaMeb)), 19.0 (d, JPC ) 6.9 Hz,
2JPC ) 5.5 Hz, P(CHMecMed)), 10.5 (C5Me5); 31P{1H} NMR (C6D6):
δ 89.0. Upon dissolution of 11 (0.022 g) in C6D6 (0.8 mL), partial
isomerization to the corresponding vinylic isomer 11b (analogous
to 10), as well as dissociation to give 3, was noticed over the course
of 24 h (ratio of 11:11b:3, ca. 21:11:1 31P NMR). Selected NMR
data for 11b: 1H NMR (C6D6): δ 12.80 (d, J ) 2.0 Hz, 1H,
RudCH), 6.54 (apparent t, J ) 2.0 Hz, 2H, pyrrole-Hs), 6.36
(apparent t, J ) 2.0 Hz, 2H, pyrrole-Hs), 3.02 (s, 3H, NMe),
2.96-2.92 (m, 2H, C(Ha)(Hb)), 1.61 (d, J ) 1.0 Hz, 15H, C5Me5),
2
P(CHMecMed)), 17.7 (d, JPC ) 7.3 Hz, P(CHMecMed)), 10.9
(C5Me5); 31P{1H} NMR (C6D6): δ 91.2; 29Si{1H} NMR (C6D6): δ
26.6, JSiH ) 157.8 Hz (1H-coupled H-29Si HMQC).
1
1
Formation of 10. To a glass vial containing a solution of 3 (0.10
g, 0.20 mmol) in benzene (7 mL) was added PhNH2 (0.019 mL,
0.20 mmol) via Eppendorf micropipette. The addition caused an
immediate color change from dark red to dark orange. After 10
min, 31P NMR data collected on an aliquot of this solution indicated
the clean conversion to two phosphorus-containing products
exhibiting resonances at 64.0 ppm (tentatively assigned as 4 · NH2Ph
by comparison of 1H NMR data to that of 4 · NH3 and 4 · NC5H11)
and 76.2 ppm (10) (ca. 4:1 ratio); after 2 h, the ratio of 4 · NH2Ph:
10 was ca. 2:1. After 72 h, 31P NMR analysis revealed the presence
of 10 and an as-yet-unidentified species (br. m, 62.1 ppm) in a
ratio of ca. 10:1. Efforts to obtain 10 in analytically pure form have
thus far proven unsuccessful. Data for 10: 1H NMR (C6D6): δ 12.88
3
3
1.19 (d of d, JPH ) 19.0 Hz, JHH ) 7.0 Hz, 3H, P(CHMeMe)),
3
3
1.05 (d of d, JPH ) 11.0 Hz, JHH ) 7.0 Hz, 3H, P(CHMeMe)),
3
3
0.85 (d of d, JPH ) 13.5 Hz, JHH ) 7.0 Hz, 3H, P(CHMeMe)),
3
3
0.65 (d of d, JPH ) 15.5 Hz, JHH ) 7.0 Hz, 3H, P(CHMeMe));
13C{1H} (C6D6): δ 249.1 (d, JPC ) 20.8 Hz, RudC), 133.2 (2
2
pyrrole-CHs), 107.3 (2 pyrrole-CHs), 99.2 (C5Me5), 49.9 (NMe),
40.7 (C1), 31.6 (d, 1JPC ) 24.9 Hz, P(CHMeMe)), 24.0 (d, 1JPC
)
25.2 Hz, P(CHMeMe)), 19.3 (d, 2JPC ) 6.2 Hz, P(CHMeMe)), 18.5
4
3
2
(d of d, JHH ) 15.5 Hz, JPH ) 2.0 Hz, 1H, RudCH), 9.71 (d,
4JHH ) 15.5 Hz, 1H, N-H), 7.27 (m, 1H, N-aryl H), 7.19 (m, 1H,
N-aryl H), 7.07 (m, 1H, aryl H), 6.88-6.83 (m, 3H, aryl Hs),
6.82-6.78 (m, 2H, N-aryl Hs), 6.73 (m, 1H, N-aryl H), 3.39-3.25
(AB m, 2H, C(H )(H )), 2.90 (m, 1H, P(CHMeaMeb)), 2.69 (s,
(d, JPC ) 10.7 Hz, P(CHMeMe)), 10.6 (C5Me5); 31P{1H} NMR
(C6D6): δ 61.6.
Synthesis of 12. Within a glovebox, a Schlenk flask was
charged with 4 · PHPh2 (0.10 g, 0.14 mmol), a magnetic stir-
bar, and benzene (6 mL). After sealing the reaction flask, it was
a
b

6298 Organometallics, Vol. 27, No. 23, 2008
Rankin et al.
removed from the glovebox, connected to a Schlenk line, and
heated at 50 °C under the influence of magnetic stirring for 7
days. Analysis of 31P NMR data collected on an aliquot of this
solution indicated quantitative conversion to 12. The solvent and
other volatile materials were removed in Vacuo, affording an
oily yellow solid. The residue was triturated with pentane (2 ×
3 mL), and the pentane was removed in Vacuo to yield 12 as an
analytically pure, beige powder (0.091 g, 0.13 mmol, 91%). Anal.
calcd for C39H49P2NRu: C 67.40; H 7.11; N 2.02. Found: C
129.4 (P-aryl CHs), 121.9 (C4 or C7), 119.6 (C7 or C4), 117.6
(C5 or C6), 116.9 (C6 or C5), 106.4 (d, J ) 13.5 Hz, C1), 94.4
1
(C5Me5), 41.0 (NMe), 30.7 (d, JPC ) 25.7 Hz, P(CHMecMed)),
24.8 (d, 1JPC ) 30.8 Hz, P(CHMeaMeb)), 21.1 (P(CHMeaMeb)), 18.8
2
(d, JPC ) 6.4 Hz, P(CHMecMed)), 18.7-18.5 (m, P(CHMeaMeb)
and P(CHMecMed)), 10.0 (C5Me5); 31P{1H} NMR (C6D6): δ 73.4
(d, 2JPP ) 31.4 Hz), 42.9 (d, 2JPP ) 31.4 Hz). A crystal of 13 suitable
for X-ray diffraction analysis was grown from a concentrated
pentane solution at -35 °C.
1
Crystallographic Solution and Refinement Details. Crystal-
lographic Characterization of 3 and 4 · NC8H11(2.5NC8H11).
Crystallographic data were obtained at 193((2) K on a Bruker
PLATFORM/SMART 1000 CCD diffractometer using a 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)
were supplied by Bruker. Gaussian integration was employed
as the absorption correction method, and the structure was solved
by use of a Patterson search/structure expansion for 3 and direct
methods for 4 · NC8H11(2.5NC8H11). Refinements were carried
out by use of full-matrix least-squares procedures (on F2) with
67.43; H 7.23; N 1.65. H NMR (C6D6): δ 10.85 (d, J ) 16.0
Hz, 1H, RudCH), 8.09 (d, 3JHH ) 8.0 Hz, 1H, C4-H or C7-H),
3
8.04 (d, JHH ) 8.0 Hz, 1H, C7-H or C4-H), 7.56-7.45 (m,
2H, P-aryl Hs), 7.38-7.28 (m, 4H, 2 P-aryl Hs and C5-H and
C6-H), 7.11-7.07 (m, 4H, 3 P-aryl Hs and C1-H), 6.98-6.95
3
(m, 3H, P-aryl CHs), 6.69 (br. d, JHH ) 15.5 Hz, 1H, N-H),
3.51 (m, 1H, P(CHMeaMeb)), 2.03 (m, 1H, P(CHMecMed)), 1.64
(s, 15H, C5Me5), 1.58-1.52 (m, 6H, NMe and P(CHMecMed)),
1.02 (d of d, 3JPH ) 15.0 Hz, 3JHH ) 6.5 Hz, 3H, P(CHMeaMeb)),
0.69 (d of d, 3JPH ) 17.5 Hz, 3JHH ) 7.5 Hz, 3H, P(CHMecMed)),
0.56 (d of d, 3JPH ) 14.5 Hz, 3JHH ) 7.0 Hz, 3H, P(CHMeaMeb));
13C{1H} (C6D6): δ 240.5 (apparent t, J ) 14.3 Hz, RudC), 142.1
1
(d, JPC ) 43.7 Hz, P-aryl C), 141.7 (m, C3a or C7a), 135.9 (d,
2
2
2
2
R1 based on Fo g 2σ(Fo ) and wR2 based on Fo g -3σ(Fo ).
Two crystallographically independent molecules of 3 were
identified in the asymmetric unit, and were refined in a
satisfactory manner; only one of the two independent molecules
of 3 is depicted in the text. One of the noncoordinated
2,6-dimethylaniline solvates in 4 · NC8H11(2.5NC8H11) was re-
fined on the basis of an inversion-disorder model, employing
an occupancy factor of 0.5 for the non-hydrogen atoms and a
common isotropic displacement parameter for C and N; the ring
carbons of this solvate were refined as an idealized hexagon with
a C-C bond distance of 1.39 Å. Otherwise, anisotropic
displacement parameters were employed throughout for the non-
hydrogen atoms, and all hydrogen atoms were added at calculated
positions and refined by use of a riding model employing
isotropic displacement parameters based on the isotropic dis-
placement parameter of the attached atom.
JPC ) 11.1 Hz, P-aryl CHs), 134.6 (m, C7a or C3a), 133.4 (d,
JPC ) 10.2 Hz, P-aryl CHs), 129.1 (P-aryl CH), 128.5 (P-aryl
CH), 127.5 (m, P-aryl CHs), 127.0 (d, JPC ) 9.3 Hz, P-aryl CHs),
122.3 (C4 or C7), 120.5 (C7 or C4), 117.9 (C5 or C6), 117.4
(C6 or C5), 106.1 (d, JPC ) 14.2 Hz, C1), 95.2 (C5Me5), 41.7
1
1
(NMe), 28.9 (d, JPC ) 26.0 Hz, P(CHMecMed)), 25.8 (d, JPC
2
) 33.0 Hz, P(CHMeaMeb)), 21.8 (P(CHMeaMeb)), 21.7 (d, JPC
2
) 6.2 Hz, P(CHMecMed)), 19.4 (d, JPC ) 6.7 Hz, P(CHMec-
2
Med)), 19.1 (d, JPC ) 3.8 Hz P(CHMeaMeb)), 10.0 (C5Me5);
2
2
31P{1H} NMR (C6D6): δ 72.6 (d, JPP ) 26.3 Hz), 64.0 (d, JPP
) 26.3 Hz). Slow evaporation of a C6H6 solution of 12 produced
a crystal of 12(C6H6)2.5 suitable for single-crystal X-ray diffrac-
tion analysis.
Synthesis of 13. To a glass vial containing a magnetically stirred
solution of 3 (0.10 g, 0.20 mmol) in benzene (6 mL) was added
PH2Ph (0.023 mL, 0.20 mmol) via Eppendorf micropipette. An
immediate lightening of the solution from dark red to a lighter red
was observed upon the addition of PH2Ph. The vial was sealed
with a PTFE-lined cap, and the solution was stirred for 15 min,
after which time the solution was red-orange in color. At this stage,
analysis of 31P NMR data collected on an aliquot of this solution
indicated the complete consumption of 3 and conversion to multiple
phosphorus-containing species. After a total reaction time of 72 h,
the solution was observed to be orange-yellow in color, and analysis
of 31P NMR data collected on an aliquot of this solution indicated
quantitative conversion to 13. The solvent and other volatile
materials were removed in Vacuo, affording an oily pale yellow
solid. The residue was triturated with pentane (2 × 3 mL), and the
pentane was removed in Vacuo to yield 13 as an analytically pure,
beige powder (0.11 g, 0.18 mmol, 88%). Anal. calcd for
C33H45P2NRu: C 64.04; H 7.33; N 2.26. Found: C 63.65; H 7.14;
Crystallographic Characterization of 4 · DMAP, 4 · PPh3(C6H6),
8, 12(C6H6)2.5, and 13. Crystallographic data were obtained at
173((2) K on a Nonius KappaCCD 4-Circle Kappa FR540C
diffractometer using a 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. Cell
parameters were initially retrieved using the COLLECT software
(Nonius), and refined with the HKL DENZO and SCALEPACK
software.27 Data reduction and absorption correction (multiscan)
were also performed with the HKL DENZO and SCALEPACK
software. The structures were solved by using the direct methods
package in SIR-97,28 and refined by use of the SHELXL97-2
program,29 employing full-matrix least-squares procedures (on F2)
2
2
with R1 based on Fo2 g 2σ(Fo ) and wR2 based on Fo2 g -3σ(Fo ).
Anisotropic displacement parameters were employed throughout
for the non-hydrogen atoms. For 8, the restraints DELU, SIMU,
and ISOR were used to restrain the anisotropic displacement
parameters for the carbon atoms of the C5Me5 ligand. With the
exception of the Ru-H in 8, the N-H in 12(C6H6)2.5, and the P-H
in 13 (the positions of which were located in the difference map
and refined) all H-atoms were added at calculated positions and
refined by use of a riding model employing isotropic displacement
1
N 2.28. H NMR (C6D6): δ 10.76 (d, J ) 17.0 Hz, 1H, RudCH),
8.02 (d, 3JHH ) 8.0 Hz, 1H, C4-H or C7-H), 7.94 (d, 3JHH ) 8.0
Hz, 1H, C7-H or C4-H), 7.48-7.43 (m, 2H, P-aryl Hs), 7.32 (t,
3JHH ) 7.5 Hz, 1H, C5-H or C6-H), 7.26 (t, 3JHH ) 7.5 Hz, 1H,
C6-H or C5-H), 7.18-7.16 (m, 3H, P-aryl Hs), 6.89-6.73 (m,
3H, N-H and P-H and C1-H), 3.38 (m, 1H, P(CHMeaMeb)),
1.97 (m, 1H, P(CHMecMed)), 1.68 (d, 3H, J ) 5.0 Hz, NMe), 1.56
(s, 15H, C5Me5), 1.34 (d of d, 3JPH ) 11.5 Hz, 3JHH ) 7.0 Hz, 3H,
(27) HKL DENZO and SCALEPACK v1.96: Otwinowski, Z.; Minor,
W. Macromolecular Crystallography; Part, A; Carter, C. W.; Sweet, R.
M., Eds.; Academic Press: San Diego, 1997; Vol. 276, pp 307-326.
(28) Altomare, A.; Cascarano, G.; Giacovazzo, C.; Guagliardi, A.;
Moliterni, A. G. G.; Burla, M. C.; Polidori, G.; Camalli, M.; Spagna, R.
J. Appl. Crystallogr. 1999, 32.
3
3
P(CHMecMed)), 0.98 (d of d, JPH ) 16.0 Hz, JHH ) 6.5 Hz, 3H,
P(CHMeaMeb)), 0.82 (d of d, 3JPH ) 17.0 Hz, 3JHH ) 7.0 Hz, 3H,
3
3
P(CHMecMed)), 0.76 (d of d, JPH ) 15.0 Hz, JHH ) 7.0 Hz, 3H
P(CHMeaMeb)); 13C{1H} (C6D6): δ 241.6 (apparent t, J ) 14.1 Hz,
RudC), 141.4 (m, C3a or C7a), 135.3 (d, J ) 17.6 Hz, C7a or
C3a), 133.6 (d, JPC ) 9.4 Hz, P-aryl CHs), 132.4 (m, P-aryl C),
(29) Sheldrick, G. M. SHELXL97-2, Program for the Solution of Crystal
Structures; University of Go¨ttingen: Go¨ttingen, Germany, 1997.

Indenyl Hemilability
Organometallics, Vol. 27, No. 23, 2008 6299
parameters based on the isotropic displacement parameter of the
attached atom.
support of this work. We also thank Drs. Michael Lumsden
and Katherine Robertson (Atlantic Region Magnetic Reso-
nance Center, Dalhousie) for their assistance in the acquisi-
tion of NMR data.
Acknowledgment. Acknowledgment is made to the
Natural Sciences and Engineering Research Council (NSERC)
of Canada (including a Discovery Grant for M. S. and a
Postgraduate Scholarship for M.A.R.), the Canada Founda-
tion for Innovation, the Nova Scotia Research and Innovation
Trust Fund, and Dalhousie University for their generous
Supporting Information Available: Crystallographic informa-
tion. This material is available free of charge via the Internet at
http://pubs.acs.org.
OM800740Z