Formation of ruthenaindenes by cyclometalation of ruthenium(II) diarylbutenyne complexes

Article abstract of DOI:10.1021/om900613y

The reaction of diarylbutenynylruthenium complexes [Ru(η³- C(C=CC₆H₄R)=C(R')C₆H₄R)(PMe ₃)₄]⁺ (C₆H₄R = C ₆H₄-4-Bu, Ph, C

Full text of DOI:10.1021/om900613y

5514 Organometallics 2009, 28, 5514–5521
DOI: 10.1021/om900613y
Formation of Ruthenaindenes by Cyclometalation of Ruthenium(II)
Diarylbutenyne Complexes
Leslie D. Field,*,† Alison M. Magill,† Mohan M. Bhadbhade,‡ and Scott J. Dalgarno§
†School of Chemistry, University of New South Wales, Sydney, Australia, 2052, ‡University of New South
Wales Analytical Centre, Sydney, Australia, 2052, and §School of Engineering and Physical Sciences-
Chemistry, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, U.K.
Received July 13, 2009
The reaction of diarylbutenynylruthenium complexes [Ru(η3-C(CtCC6H4R)dC(R0)C6H4R)-
(PMe3)4]þ (C6H4R = C6H4-4-tBu, Ph, C6H4-4-Me; R0 = H, Me) with dimethylmagnesium yields
the cyclometalated ruthenaindene complexes [Ru(C(CtCC6H4R)dC(R0)C6H3R)(PMe3)4] with
ruthenium incorporated into the five-membered ring of an indene. The reaction involves the initial
formation of methylruthenium complexes, which then rearrange with the elimination of methane
to yield the product. The complexes [Ru(C(CtCC6H4R)dC(R0)C6H3R)(PMe3)4] (C6H4R = C6H4-
4-tBu, R0 = H; C6H4R = Ph, R0 = Me) were crystallographically characterized.
Introduction
Butenynyl complexes have been synthesized by reaction of
transition-metal complexes with terminal alkynes,8-13 inser-
tion of 1,4-disubstituted buta-1,3-diynes into a transition-
metal hydride bond,14,15 coupling of coordinated acetylide
units in transition-metal acetylide complexes,16,17 and pro-
tonation of low-valent complexes bearing η2-coordinated
butadiynyl ligands.6,15 The butenynyl ligand is known with
either η1-coordination3,11,18 or η3-coordination,8,12,15,16,19
depending on the metal center.
Under acidic conditions, iron and ruthenium bis-
acetylides protonate at the β-carbon to form acetylide-
vinylidene complexes, which may rearrange with coupl-
ing of the organic ligands to form metal butenynes
(Scheme 1).5,13,20,21
Transition-metal butenynyl complexes have been identified
as key intermediates in the metal-catalyzed head-to-head cou-
plings of alkynes leading to E/Z-1,4-disubstituted-1-buten-3-
ynes1,2 and E/Z-1,4-disubstituted butatrienes.3 This alkyne
dimerization reaction is an attractive, atom-efficient route for
the formation of enyne moieties that play an important role in
medicinal and natural product chemistry and in organic synth-
esis.4 We and others have been studying the formation of
transition-metal butenynyl complexes with a view to better
understanding the structure and chemistry of these species.1,5-9
*To whom correspondence should be addressed. Tel: þ61 2 9385
2700. Fax: þ61 2 9385 8008. E-mail: L.Field@unsw.edu.au.
(1) Rappert, T.; Yamamoto, A. Organometallics 1994, 13, 4984–4993.
(2) (a) Bianchini, C.; Peruzzini, M.; Zanobini, F.; Frediani, P.;
Albinati, A. J. Am. Chem. Soc. 1991, 113, 5453–5454. (b) Bianchini, C.;
Bohanna, C.; Esteruelas, M. A.; Frediani, P.; Meli, A.; Oro, L. A.; Peruzzini, M.
Organometallics 1992, 11, 3837–3844. (c) Yi, C. S.; Liu, N. H. Organo-
metallics 1998, 17, 3158–3160. (d) St Clair, M.; Schaefer, W. P.;
Bercaw, J. E. Organometallics 1991, 10, 525–527. (e) Horton, A. D.
J. Chem. Soc., Chem. Commun. 1992, 185–187. (f) Yi, C. S.; Liu, N. H.;
Rheingold, A. L.; Liable-Sands, L. M. Organometallics 1997, 16, 3910–3913.
(3) Wakatsuki, Y.; Yamazaki, H.; Kumegawa, N.; Satoh, T.; Satoh,
J. Y. J. Am. Chem. Soc. 1991, 113, 9604–9610.
In the metal butenynes that have been structurally char-
acterized, the coordinated vinyl fragment preferentially
adopts the stereochemistry with the metal center at one
end of the double bond trans to the larger substituent at
(12) Jia, G. C.; Rheingold, A. L.; Meek, D. W. Organometallics 1989,
8, 1378–1380.
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Turner, P. J. Chem. Soc., Dalton Trans. 1999, 2557–2562.
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r
pubs.acs.org/Organometallics
Published on Web 08/31/2009
2009 American Chemical Society

Article
Organometallics, Vol. 28, No. 18, 2009 5515
Scheme 1
Scheme 3
Results and Discussion
The reaction of cis-RuMe2(PMe3)4 with terminal alkynes
is known25 to furnish bis(acetylido)ruthenium(II) com-
plexes. These complexes, when protonated with weak acids
such as 2,6-lutidinium salts, give ruthenium(II) butenyne
complexes, [Ru(η3-C(CtCR)dC(H)R)(PMe3)4]þ (3a-c) in
good (50-80%) yield20 (Scheme 4), while the use of methyl
trifluoromethanesulfonate in place of acid results in the
formation of the related methyl-substituted butenyne com-
plex [Ru(η3-C(CtCPh)dC(Me)Ph)(PMe3)4]þ (3d).20
Scheme 2
t
t
When [Ru(η3-C(CtCC6H4 Bu)dC(H)C6H4 Bu)(PMe3)4]-
BF4 (3a) reacted with dimethylmagnesium in THF solution,
the major product of the reaction was identified as the ortho-
the other end of the double bond. The trans stereoisomer
presumably has less steric strain than the cis isomer, where
there would be significant crowding between the metal center
and the larger substituent. In the case of [Ru(η3-C-
(CtCMe)dC(H)Me)(PMe3)4]þ, the complex can be formed
as a mixture of E- and Z-stereoisomers at low temperature
but readily isomerizes to the more stable Z-isomer on
warming.20
The structures of known ruthenium butenynes confirm a
degree of electron delocalization, with the preferred η3-bond-
ing mode for the enyne probably best described as a hybrid
between a σ-vinyl/π-alkynyl butenyne complex and an η2-1,3-
butadienyl complex.8,12,22 We have previously reported the
attack of hydride (from LiAlH4) on the C2 carbon of the
coordinated enyne of [Fe(η3-C(CtCR)dC(H)R)(dmpe)2]-
[PF6] (1) (R = Me, Ph) to give a metallocyclobutene product,
t
metalated ruthenaindene [Ru(C(CtCC6H4 Bu)dC(H)C6H3-
tBu)(PMe3)4] (4a) (Scheme 5), and the structure of the com-
plex was confirmed by X-ray crystallography (Figure 1,
Table 1). Ruthenaindenes 4b and 4c were formed in an exactly
analogous manner when the corresponding ruthenium bute-
nynes 3b and 3c were treated with Me2Mg. The methyl-
substituted butenyne 3d also yields a ruthenaindene, 4d, upon
reaction with Me2Mg. Slow cooling of a saturated hexane
solution of the complex gave X-ray quality crystals of 4d
(Figure 2, Table 1).
Structurally characterized monometallic ruthenaindenes
are rare in the literature, with three examples previously
reported.26,27 Complex 4a exhibits a distorted octahedral
geometry, with the expected unsymmetrical coordination
environment about the metal center. The Ru-Caryl bond,
˚
[Fe-CdC(H)R)C(H)dCR(dmpe)2] (2).5 The formation of
the metallocyclobutene by attack of the hydride at the
butenyne ligand is not unreasonable since one canonical
form of the metal butenyne imparts a partial positive
charge onto C2 of the coordinated enyne (Scheme 2).16 The
ferracyclobutene products are unstable in the solid state,
but have been characterized by multinuclear NMR spectro-
scopy.
at 2.150(2) A, is slightly longer than the value reported for the
related complexes [Cp*Ru(C(Ph)dC(R)C6H4)NO)] (R =
26
Ph, 2.088(8) A; R = Me, 2.093 A), but comparable to
˚
˚
that of [Ru(C(C(O)OCH3)dC(C(O)OCH3)C6H4)(CO)2-
˚
27
(PMe2Ph)2] (2.122 A). The remaining ruthenium-carbon
bond (2.147(2) A) is slightly longer than those in the
˚
previously reported examples (2.129(5), 2.114(7),26 and
27
2.098 A ). The ruthenaindene core is essentially planar,
The related η3-allenyl/propargyl complexes display en-
hanced reactivity toward nucleophilic addition at the central
carbon of the bound organic ligand,23 leading to metalla-
cyclobutene products (Scheme 3).24 This suggests that bute-
nyne complexes should be prone to attack by other
nucleophiles, possibly allowing isolation and complete
characterization of the expected metallocyclobutene pro-
ducts.
˚
with the exocyclic aromatic ring being twisted relative to this
plane by approximately 23°.
The methyl-substituted complex 4d is isostructural with
4a, with some minor differences in bond lengths. The
Ru-Caryl bond is shorter (2.132(2) vs 2.150(2) A), while
the double bond in the five-membered metallocyclic ring is
˚
slightly elongated (1.367(3) vs 1.346(2) A). The core bond
˚
angles are essentially identical. The exocyclic aromatic ring
of 4d is twisted relative to the ruthenaindene core by
approximately 55°.
While ruthenaindenes are relatively rare in the literature,
metalloindenes incorporating early transition metals are
(22) (a) Bianchini, C.; Innocenti, P.; Peruzzini, M.; Romerosa, A.;
Zanobini, F. Organometallics 1996, 15, 272–285. (b) Jia, G. C.; Gallucci, J.
C.; Rheingold, A. L.; Haggerty, B. S.; Meek, D. W. Organometallics 1991,
10, 3459–3465.
(23) (a) Chen, J.-T. Coord. Chem. Rev. 1999, 190-192, 1143–1168. (b)
Ogoshi, S.; Nishida, T.; Tsutsumi, K.; Ooi, M.; Shinagawa, T.; Akasaka, T.;
Tamane, M.; Kurosawa, H. J. Am. Chem. Soc. 2001, 123, 3223–3228.
(24) (a) Casey, C. P.; Nash, J. R.; Yi, C. S.; Selmeczy, A. D.; Chung,
S.; Powell, D. R.; Hayashi, R. K. J. Am. Chem. Soc. 1998, 120, 722–733.
(b) Casey, C. P.; Boller, T. M.; Samec, J. S. M.; Reinert-Nash, J. R.
Organometallics 2009, 28, 123–131.
(25) Field, L. D.; Magill, A. M.; Dalgarno, S. J.; Jensen, P. Eur. J.
Inorg. Chem. 2008, 27, 4248–4254.
(26) Burns, R. M.; Hubbard, J. L. J. Am. Chem. Soc. 1994, 116, 9514–
9520.
(27) Crook, J. R.; Giordano, F.; Mawby, R. J.; Reid, A. J.; Reynolds,
C. D. Acta Crystallogr. Sect. C, Cryst. Struct. Commun. 1990, 46, 41–44.

5516 Organometallics, Vol. 28, No. 18, 2009
Field et al.
Scheme 4
Scheme 5
˚
Table 1. Selected Bond Lengths (A) and Angles (deg) for
t
t
[Ru(C(CtCC6H4 Bu)dC(H)C6H3 Bu)(PMe3)4] (4a) and
[Ru(C(CtCPh)dC(Me)C6H4)(PMe3)4] (4d)
parameter
4a
4d
parameter
4a
4d
Ru(1)-C(9) 2.147(2) 2.141(2) Ru(1)-P(2)
Ru(1)-C(12) 2.150(2) 2.132(2) Ru(1)-P(3)
C(9)-C(10) 1.346(2) 1.367(3) Ru(1)-P(4)
2.3818(5) 2.3805(7)
2.3308(5) 2.3131(5)
2.3575(6) 2.3596(7)
C(10)-C(11) 1.444(3) 1.457(3) C(9)-Ru(1)-C(12) 77.86(7) 77.32(9)
C(11)-C(12) 1.427(3) 1.426(3) P(1)-Ru(1)-P(3) 168.92(2) 170.09(2)
C(7)-C(8)
1.217(3) 1.214(3) P(2)-Ru(1)-P(4) 99.02(2) 99.65(2)
Ru(1)-P(1) 2.3486(6) 2.3493(6)
Figure 2. Molecular projection of [Ru(C(CtCPh)dC(Me)C6-
H4)(PMe3)4] (4d). Thermal ellipsoids are shown at the 50%
probability level, while hydrogen atoms have an arbitrary radius
˚
of 0.1 A. Hydrogen atoms on phosphine ligands have been
omitted for clarity.
Figure 1. Molecular projection of [Ru(C(CtCC6H4tBu)dC(H) C6-
H3tBu)(PMe3)4] (4a). Thermal ellipsoids are shown at the 50%
probability level, while hydrogen atoms have an arbitrary radius of
0.1 A. Hydrogen atoms on phosphine ligands have been omitted for
clarity.
Scheme 6.30
˚
reasonably common and are typically prepared by the addi-
tion of an internal alkyne to a benzyne complex.28 Metalloin-
denes of late transition metals have previously been prepared
(28) (a) Mattia, J.; Humphrey, M. B.; Rogers, R. D.; Atwood, J. L.;
Rausch, M. D. Inorg. Chem. 1978, 17, 3257–3264. (b) Dvorak, J.; O'Brien,
R. J.; Santo, W. J. Chem. Soc., Chem. Commun. 1970, 411–412. (c) Masai,
H.; Sonogashira, K.; Hagihara, N. Bull. Chem. Soc. Jpn. 1968, 41, 750–751.
(d) Nettles, S. M.; Petersen, J. L. J. Organomet. Chem. 2007, 692, 4654–
4660. (e) Kanj, A.; Meunier, P.; Gautheron, B.; Dubac, J.; Daran, J. C.
J. Organomet. Chem. 1993, 454, 51–58. (f) Buijink, J. K. F.; Kloetstra, K.
R.; Meetsma, A.; Teuben, J. H.; Smeets, W. J. J.; Spek, A. L. Organometallics
1996, 15, 2523–2533. (g) Mashima, K.; Tanaka, Y.; Nakamura, A. Organo-
metallics 1995, 14, 5642–5651. (h) Lee, H.; Bonanno, J. B.; Hascall, T.;
Cordaro, J.; Hahn, J. M.; Parkin, G. J. Chem. Soc., Dalton Trans. 1999,
1365–1368. (i) Butler, I. R.; Cullen, W. R.; Einstein, F. W. B.; Jones, R. H. J.
Organomet. Chem. 1993, 463, C6–C9. (j) Boring, E.; Sabat, M.; Finn, M. G.;
Grimes, R. N. Organometallics 1998, 17, 3865–3874.
by elimination of triflic acid from ruthenium- or rhodium-
vinyl and osmium-vinylidene complexes.26,29 The related
osmium(II) complex [(Cp)Os(C(CtCPh)dC(H)C6H4)(H)-
(PiPr3)] has been reported to form from the reaction of an
osmium vinylidene complex with lithium phenylacetylide
(Scheme 6).30
Ruthenaindene 4a exhibits three resonances in the 31P{1H}
NMR spectrum in the ratio 1:2:1, consistent with an
ꢀ
~
(29) (a) Buil, M. L.; Esteruelas, M. A.; Lopez, A. M.; Onate, E.
Organometallics 1997, 16, 3169–3177. (b) Werner, H.; Wolf, J.; Schubert,
U.; Ackermann, K. J. Organomet. Chem. 1983, 243, C63–C70.
(30) Esteruelas, M. A.; Hernandez, Y. A.; Lopez, A. M.; Onate, E.
Organometallics 2007, 26, 6009–6013.

Article
Organometallics, Vol. 28, No. 18, 2009 5517
Scheme 7
octahedral complex with two equivalent axial phosphines
and two nonequivalent equatorial phosphines. One of the
equatorial phosphines appears at unusually high field (δ
-17.4 ppm). In addition, there is a complex phosphorus-
corresponding to carbons of the metallocyclobutene, and
these display a long-range correlation in the 1H-13C HMBC
to the methyl resonance at δ 1.27 ppm.31 Complex 8 is
assigned as the metallocyclobutene complex, which would
form by direct methylation of the butenyne 3c at the central
carbon of the bound enyne ligand.
1
coupled multiplet at δ 8.10 ppm in the H NMR spectrum
(C6D6) attributed to the proton on the five-membered metal-
containing ring.
Mechanistically, the formation of ruthenaindenes from
the butenyne starting materials is unexpected. Overall, the
reaction involves decoordination of the π-bound acetylene of
the butenyne fragment, Z f E isomerization of the metal-
substituted alkene, ortho-metalation of the aromatic ring
attached to the vinyl group of the butenyne, and loss of a
proton.
Since the Me2Mg is not incorporated into the reaction
product, it could be argued that it behaves merely as a
relatively strong base in this reaction. Attempts to prepare
ruthenaindenes 4a-c using KOtBu in place of Me2Mg
simply resulted in formation of the bis(acetylide) complexes
trans-Ru(CtCR)2(PMe3)4. This reaction with KOtBu is not
unprecedented since metal butenynes are known to revert to
metal bisacetylides on treatment with base,5 presumably via
a process that is essentially the reverse of the reaction
depicted in Scheme 1. Clearly Me2Mg does not act merely
as a base in its reaction with metal butenynes.
The second most abundant product is the known bis-
(acetylide) trans-Ru(CtCC6H4-4-Me)2(PMe3)4 (5), formed
by simple deprotonation and cleavage of the butenyne start-
ing material.
The major product of the reaction at 238 K is assigned as
complex 6 (or its isomer 7). This product contains a phos-
1
phorus-coupled doublet in the H NMR spectrum corres-
ponding to a vinylic proton at δ 6.62 ppm (4JPH = 5.0 Hz).
The spectrum also contains a broad phosphorus-coupled
multiplet at δ -0.46 ppm, corresponding to a ruthenium-
bound methyl group. The methyl resonance shows broaden-
ing down to at least 188 K and shows exchange (confirmed
by exchange peaks in the NOESY spectrum) with another
Ru-bound methyl resonance due to a minor product (<15%)
in the reaction mixture (δ -1.56 ppm). The second species is
probably the alternate stereoisomer of 6; that is, if 6 is the
E-isomer, then 7 is the Z-isomer or vice versa (Scheme 8).
Complex 6 is the product that would be expected from the
direct attack of the methylating agent on the cationic metal
center with loss of the coordinated alkyne. At low tempera-
ture, the deprotonation of the butenyne 3c to yield the
bisacetylide 5 occurs in competition with the methylation
reactions that give rise to 6/7 and 8.
The reaction between [Ru(η3-C(CtCC6H4CH3)dC-
(H)C6H4CH3)(PMe3)4]BF4 (3c) and Me2Mg in THF-d8
was monitored carefully by NMR spectroscopy at low
temperature (238 K). At this temperature, no ruthenaindene
product is formed. On addition of Me2Mg to 3c at 238 K,
three major products are present in the reaction mixture
immediately after the reagents are mixed, in a ratio of
approximately 20:30:50, and these are assigned as complexes
8, 5, and 6/7, respectively (Scheme 7).
The minor product, 8, exhibits a 1-proton phosphorus-
coupled vinylic resonance at δ 6.27 ppm (d, 4JPH = 7.0 Hz)
and a 3-proton methyl resonance at δ 1.27 ppm (m) in the 1H
NMR spectrum. There are no alkynyl resonances associated
with complex 8 in the 13C{1H} NMR spectrum. There are
two para-substituted aromatic rings, and the methyl reso-
nance at δ 1.27 exhibits an NOE to two sets of aryl protons
on different aromatic rings. The 13C{1H} NMR spectrum
exhibits resonances at low field (δ 163.5 and 146.0 ppm)
Above 248 K, the signals corresponding to 6 broaden, and
this complex rapidly decomposes near room temperature to
yield the ruthenaindene product 4c together with other
minor products. Free methane is also visible as a sharp
singlet in the 1H NMR spectrum at δ 0.20 ppm.
(31) The related ferracyclobutene [Fe-C(dC(H)Ph)C(H)d CPh-
(dmpe)2] displays resonances at δ 141.9, 166.6, and 167.5 ppm in the
13C{1H} NMR spectrum corresponding to the carbon atoms of the
cyclobutene core. See ref 5.
The cyclometalation of complex 6 to form the ruthenain-
dene product 4c must occur from the Z-stereoisomer of 6/7

5518 Organometallics, Vol. 28, No. 18, 2009
Field et al.
Scheme 8
(Scheme 8). We have previously reported that [Ru(η3-C-
(CtCMe)dC(H)Me)(PMe3)4]þ can be formed as a mixture
of E- and Z- stereoisomers at low temperature but readily
isomerizes to the more stable Z-isomer on warming.20 Indeed
the E/Z isomerization of vinyl-type complexes is well estab-
lished in the literature and is often proposed to proceed via a
carbene-type structure in which rotation around the C-C
bond is possible.26,32
Ortho-metalation of aryl ligands resulting from methane
elimination is not unprecedented; for example the reaction of
FeMe2(PMe3)4 with 1-(diphenylphosphino)naphthalene or
benzyldiphenylphosphine yields metalated methyl iron com-
plexes via selective activation of a C-H aryl bond.33 Analo-
gous reactions are also known for cobalt.34
Experimental Section
All syntheses and manipulations involving air-sensitive com-
pounds were carried out using standard vacuum line and Schlenk
techniques under an atmosphere of dry nitrogen or argon. Diethyl
ether, tetrahydrofuran, petroleum ether, toluene, and benzene were
dried and degassed by refluxing over standard drying agents35
under an atmosphere of dry nitrogen and were freshly distilled
prior to use. All other solvents were dried according to standard
methods. THF-d8 and benzene-d6 were dried over sodium benzo-
phenone ketyl and vacuum transferred into ampules prior to use.
˚
Acetone-d6 was dried over 4 A molecular sieves.
Nuclear magnetic resonance spectra were recorded on a
Bruker DMX600 (operating at 600.13, 150.92, and 242.95
MHz for 1H, 13C, and 31P, respectively), Bruker Avance III
(operating at 500.15, 125.76, and 202.46 MHz for 1H, 13C, and
31P, respectively), Bruker Avance III 400 (operating at 400.13,
100.61, and 161.98 MHz for 1H, 13C, and 31P, respectively), or a
Conclusion
1
Bruker DPX300 (operating at 300.13 and 121.49 MHz for H
The reaction of aryl-substituted butenynylruthenium
compounds with Me2Mg provides a novel synthetic route
to alkynyl-substituted ruthenaindenes. The mechanism of
formation involves an initial change from η3- to η1-binding
in the butenynyl ligand, induced by attack of Me- at the
metal center to yield a methyl-η1-butenynylruthenium com-
plex. The double bond of the enyne isomerizes from Z to E
followed by elimination of methane with metalation of an
aromatic ring to yield the final product.
The reaction sequence provides a good synthetic approach
to new members of this relatively rare class of organometallic
compound with ruthenium embedded within a highly con-
jugated organic framework.
and 31P, respectively) at 300 K unless otherwise stated. 1H and
13C NMR spectra were referenced to residual solvent reso-
nances, while 31P NMR spectra were referenced to external
H3PO4. A solution of dimethylmagnesium in THF was prepared
according to the literature.36 cis-RuMe2(PMe3)4 was prepared
37
from the reaction of trans-RuCl2(PMe3)4 with Me2Mg in
THF; the NMR spectra were identical to that reported in the
literature.38 The butenyne complexes 3b-d were prepared as
described previously.20
t
t
[Ru(η3-C(CtCC6H4 Bu)dC(H)C6H4 Bu)(PMe3)4]BF4 (3a).
A solution of cis-RuMe2(PMe3)4 (0.348 g, 0.880 mmol) in
THF (20 mL) was treated with 4-tert-butylphenylacetylene
(0.7 mL, 3.88 mmol). The mixture was warmed to 40 °C for
2 h, before the volatiles were removed under reduced pressure.
(32) (a) Huggins, J. M.; Bergman, R. G. J. Am. Chem. Soc. 1981, 103,
3002–3011. (b) Werner, H.; Weinand, R.; Knaup, W.; Peters, K.; von
Schnering, H. G. Organometallics 1991, 10, 3967–3977.
(35) Perrin, D. D.; Armarego, W. L. F., Purification of Laboratory
Chemicals, 3rd ed.; Pergamon Press Ltd.: Oxford, 1988.
(36) Luhder, K.; Nehls, D.; Madeja, K. J. Prakt. Chem. 1983, 325,
1027–1029.
€
(33) Beck, R.; Zheng, T.; Sun, H.; Li, X.; Florke, U.; Klein, H. F.
J. Organomet. Chem. 2008, 693, 3471–3478.
(37) McNeill, K.; Andersen, R. A.; Bergman, R. G. J. Am. Chem. Soc.
1997, 119, 11244–11254.
(38) Andersen, R. A.; Jones, R. A.; Wilkinson, G. J. Chem. Soc.,
Dalton Trans. 1978, 446–453.
(34) (a) Klein, H. F.; Beck, R.; Florke, U.; Haupt, H. J. Eur. J. Inorg.
Chem. 2003, 1380–1387. (b) Klein, H. F.; Schneider, S.; He, M. Z.; Floerke,
U.; Haupt, H. J. Eur. J. Inorg. Chem. 2000, 2295–2301.

Article
Organometallics, Vol. 28, No. 18, 2009 5519
The residual sticky solid was dissolved in THF, and 2,6-lutidi-
nium tetrafluoroborate (0.153 g, 0.785 mmol) was added and the
mixture stirred at room temperature. After 80 min, the volatiles
wereremovedunder reduced pressureandthe residuewas washed
with Et2O (3 ꢁ 5 mL) and dried in vacuo to give [Ru(η3-
(CtC-C6H4), 35.3 (C(CH3)3), 35.0 (C(CH3)3), 32.6 (C8), 31.8
(C7), 26.5 (C9), 25.3 (C10), 21.8 (C11) ppm.
[Ru(C(CtCPh)dC(H)C6H4)(PMe3)4] (4b).
t
t
C(CtCC6H4 Bu)dC(H)C6H4 Bu)(PMe3)4]BF4, 3a, as a yellow
powder. Yield: 0.463 g (65%). Anal. Calcd for C36H63F4P4RuB:
C, 53.54; H, 7.86. Found: C, 53.65; H, 7.58. 31P{1H} NMR
(acetone-d6, 242 MHz): δ 0.35 (dt, 2JPP = 33.2, 22.5 Hz, 1P, Peq),
-9.10 (apparent t, splitting = 31.9 Hz, 2P, Peq), -16.35 (m, 1P,
1
Pax) ppm. H NMR (acetone-d6, 600 MHz): δ 7.78 (AA0 of
AA0XX0, 2H, ArH), 7.74 (AA0 of AA0XX0, 2H, ArH), 7.59 (XX0
of AA0XX0, 2H, ArH), 7.50 (XX0 of AA0XX0, 2H, ArH), 7.11 (d,
2
4JPH = 4.4 Hz, 1H, dC(H)), 1.87 (d, JPH = 8.6 Hz, 9H,
Peq(CH3)3), 1.82 (d, 2JPH = 7.3 Hz, 9H, Peq(CH3)3), 1.37 (s, 9H,
C(CH3)3), 1.34 (s, 9H, C(CH3)3), 1.21 (apparent t, splitting =
3.0 Hz, 18H, Pax(CH3)3) ppm. 13C{1H} NMR (75 MHz, acet-
one-d6): δ 152.7 (C-C(CH3)3), 150.7 (C-C(CH3)3), 146.9 (m, Ru-
C), 136.4 (d, JPC = 4.6 Hz, ArCipso), 132.4 (ArCH), 130.4
(dCH), 127.1 (ArCH), 126.7 (2 ꢁ ArCH), 126.3 (ArCipso),
115.1 (CtCAr), 59.0 (CtCAr), 35.5 (C(CH3)3), 35.2
A solution of [Ru(η3-C(CtCPh)dC(H)Ph)(PMe3)4]BF4, 3b
(0.0518 g, 0.0745 mmol), in THF (20 mL) was treated with
Me2Mg (1 mL, 0.15 M in THF, 0.15 mmol). The mixture was
stirred at room temperature for 1 h before the volatiles were
removed under reduced pressure. The residue was extracted with
benzene (20 mL) and the extract filtered through Celite to give a
clear yellow filtrate. The filter-cake was washed with additional
benzene (2 ꢁ 5 mL) and the combined filtrate concentrated
(C(CH3)3), 31.7 (C(CH3)3), 31.5 (C(CH3)3), 25.2 (d, JPC =
25.7 Hz, Peq(CH3)3), 24.0 (d, JPC = 30.2 Hz, Peq(CH3)3), 18.5
(apparent t, splitting = 14.0 Hz, Pax(CH3)3) ppm.
t
[Ru(C(CtCC6H4 Bu)dC(H)C6H3 Bu)(PMe3)4] (4a).
t
under reduced pressure to give [Ru(C(CtCPh)dC(H)C6H4)-
(PMe3)4], 4b, as a yellow solid. Yield: 0.0291 g (64%). Anal.
Calcd for C28H46P4Ru: C, 55.35; H, 7.63. Found: C, 55.26; H,
7.83. 31P{1H} NMR (121 MHz, C6D6): δ -6.80 (apparent t,
splitting = 28.5 Hz, 2P, Pax), -12.42 (dt, 2JPP = 28.6, 15.1 Hz,
2
1
1P, Peq), -16.48 (dt, JPP = 28.6, 15.4 Hz, 1P, Peq) ppm. H
NMR (600 MHz, C6D6): δ 8.10 (m, 1H, =CH), 7.70 (m, 1H,
H1), 7.61 (m, 2H, H6), 7.46 (d, 3JHH = 7.2 Hz, 1H, H4), 7.21 (m,
1H, H3), 7.17 (m, 2H, H7), 7.05 (m, 1H, H2), 7.03 (m, 1H, H8),
1.38 (d, 2JPH = 5.5 Hz, 9H, H10), 1.22 (d, 2JPH = 5.2 Hz, 9H,
H9), 0.96 (apparent t, splitting = 2.7 Hz, 18H, H11) ppm.
Selected 1H{31P} NMR (600 MHz, C6D6): δ 8.10 (s, 1H, dCH),
7.70 (d, 3JHH = 7.5 Hz, 1H, H1), 7.61 (d, 3JHH = 7.6 Hz, 2H,
H6), 7.46 (d, 3JHH = 7.2 Hz, 1H, H4), 7.21 (m, 1H, H3), 7.17 (m,
2H, H7), 7.05 (m, 1H, H2), 7.03 (m, 1H, H8) ppm. 13C{1H,31P}
NMR (151 MHz, C6D6): δ 181.9 (CR of C6H4), 160.8
(CipsoC6H4), 156.9 (=CH), 156.7 (Ru-C), 141.7 (C1), 131.1
(C6), 129.0 (C7), 126.4 (CipsoC6H5), 126.3 (C8), 123.1 (C4), 122.7
(C2), 122.0 (C3), 109.0 (CtC-Ph), 94.6 (CtC-Ph), 26.1 (C9),
25.5 (C10), 21.7 (C11) ppm.
t
t
A
solution of [Ru(η3-C(CtCC6H4 Bu)dC(H)C6H4 Bu)-
(PMe3)4]BF4, 3a (0.0743 g, 0.0920 mmol), in THF (10 mL)
was treated with Me2Mg (0.68 mL, 0.15 M solution in THF, 0.10
mmol), and the mixture stirred at room temperature overnight.
The volatiles were removed under reduced pressure, and the
residue was extracted with hexane (3 ꢁ 5 mL). The combined
hexane extracts were filtered through Celite and concentrated
[Ru(C(CtCC6H4Me)dCH)C6H3Me)(PMe3)4] (4c).
under reduced pressure. [Ru(C(CtCC6H4tBu)dC(H)C6H3tBu)-
(PMe3)4], 4a, was obtained as an orange solid. Yield: 0.0366 g
(55%). Crystals suitable for X-ray diffraction were obtained by
slow evaporationofa hexane solution of the product. Anal. Calcd
for C36H62P4Ru: C, 60.07; H, 8.68. Found: C, 59.96; H, 8.53.
31P{1H} NMR (121 MHz, C6D6): δ -5.38 (apparent t, splitting
= 27.8 Hz, 2P, Pax), -10.73 (dt, 2JPP = 30.0, 15.0 Hz, 1P, Peq),
-15.35 (dt, 2JPP = 26.7, 15.1 Hz, 1P, Peq) ppm. 1H NMR (500
MHz, C6D6): δ 8.10 (m, 1H, dCH), 7.69 (br d, JPH = 5.0 Hz, 1H,
H1), 7.62 (AA0 ofAA0XX0, 2H, H5), 7.38 (dd, 3JHH = 7.7Hz, JHP
= 1.3 Hz, 1H, H3), 7.28 (XX0 of AA0XX0, 2H, H6), 7.12 (br d,
3JHH = 7.7 Hz, 1H, H2), 1.51 (s, 9H, H8), 1.45 (d, 2JPH = 5.4 Hz,
9H, H10), 1.30 (d, 2JPH = 5.1 Hz, 9H, H9), 1.22 (s, 9H, H7), 0.96
(apparent t, splitting = 2.8 Hz, 18H, H11) ppm. Selected 1H{31P}
NMR (500 MHz, C6D6): δ 8.10 (s, 1H, H4), 7.69 (d, 4JHH = 1.7
Hz, 1H, H1), 7.62 (AA0 of AA0XX0, 2H, H5), 7.38 (dd, 3JHH
=
7.7 Hz, 1H, H3), 7.28 (XX0 of AA0XX0, 2H, H6), 7.12 (dd, 3JHH
= 7.7 Hz, 4JHH = 1.7 Hz, 1H, H2) ppm. 13C{1H,31P} NMR (125
MHz, THF-d8): δ 181.3 (CR of C6H3), 158.3 (Ru-C-CtC), 156.4
(dCH), 155.8 (CipsoC6H3), 149.2 (CC6H4C(CH3)3), 143.7
(CC6H3C(CH3)3), 139.5 (C1), 130.8 (C5), 125.9 (C6), 125.8
(CipsoC6H4), 121.8 (C3), 118.0 (C2), 108.3 (CtC-C6H4), 94.2
A solution of [Ru(η3-C(CtCC6H4-4-Me)dC(H)C6H4-4-Me)-
(PMe3)4]BF4 (0.1152 g, 0.159 mmol) in THF (20 mL) was
treated with Me2Mg (2.5 mL, 0.15 M in THF, 0.38 mmol).
The mixture was stirred at room temperature for 1 h before the
volatiles were removed under reduced pressure. The residue was

5520 Organometallics, Vol. 28, No. 18, 2009
Field et al.
Table 2. Crystallographic and Structure Refinement Data for 4a and 4d
4a
4d
chemical formula
Mr
C
719.81
orthorhombic, P212121
100(2)
9.9351(8)
36H62P4Ru
C29H48P4Ru
621.62
monoclinic, P2(1)/n
150(2)
18.2619(7)
cell syst, space group
temp (K)
˚
a (A)
˚
b (A)
11.5379(11)
˚
32.773(3) A
9.7641(4)
19.3009(7)
˚
c (A)
β (deg)
116.9080(10)
3069.0(2)
3
V (A )
˚
3756.8(6)
Z
4
1.273
0.61
Yellow Block
0.6 ꢁ 0.5 ꢁ 0.25
0.786
4
1.345
0.74
Yellow Plates
Dx (Mg m-3
)
μ(Mo KR) (mm-1
cryst form, color
cryst size (mm)
Tmin
Tmax
N, Nind
)
0.38 ꢁ 0.17 ꢁ 0.13
0.767
0.910
0.862
108 552, 10 809
9942
0.069
30.8°
0.030, 0.057, 1.03
10 809
388
22 796, 5381
5058
0.047
25.0
0.027, 0.111, 0.94
5381
355
Nobs (I > 2σ(I))
Rint
θmax (deg)
R[F2 > 2σ(F2)], wR(F2), S
no. of reflns
no. of params
H-atom treatment
constrained refinement
mixture of independent
and constrained refinement
weighting scheme
w = 1/[σ2(Fo2) þ (0.0206P)2 þ
calculated w = 1/[σ2(Fo2) þ (0.1P)2 þ
1.0017P] where P = (Fo þ 2Fc2)/3
0.7602P] where P = (Fo þ 2Fc2)/3
2
2
(Δ/σ)max
ΔFmax, ΔFmin (e A
0.002
0.48, -0.45
0.003
0.62, -0.78
-3
˚
)
extracted with benzene (20 mL) and the extract filtered through
Celite to give a clear yellow filtrate. The filter-cake was washed with
additional benzene (2 ꢁ 5 mL) and the combined filtrate concen-
trated under reduced pressure to give 4c as a yellow solid. Yield:
0.051 g (49%). Anal. Calcd for C30H50P4Ru: C, 56.68; H, 7.93.
Found: C, 56.48; H, 7.99. 31P{1H} NMR (121 MHz, THF-d8): δ
under reduced pressure. The residue was extracted with benzene
(20 mL) and the extract filtered through Celite to give a clear yellow
filtrate. The filter-cake was washed with additional benzene (2 ꢁ 5
mL) and the combined filtrate concentrated under reduced pres-
sure to give 4d as a yellow solid. Yield: 0.133 g (61%). Slow cooling
a saturated hexane solution of the complex grew crystals of X-ray
quality. Anal. Calcd for C29H48P4Ru: C, 56.03; H, 7.78. Found: C,
56.17; H, 7.83. 31P{1H} NMR (THF-d8): δ -5.4 (dd, 2JPP = 27.6,
-7.79 (apparent t, splitting = 28.7 Hz, 2P, Pax), -13.50 (dt, 2JPP
=
28.7, 15.0 Hz, 1P, Peq), -17.61 (dt, 2JPP = 28.0, 15.0 Hz, 1P, Peq)
ppm. 1H NMR (500 MHz, C6D6): δ8.10 (m, 1H, dCH), 7.54 (AA0
of AA0XX0, 2H, H5), 7.53 (br d, JPH = 4.4 Hz, 1H, H1), 7.37 (dd,
3JHH = 7.4 Hz, JHP = 1.0 Hz, 1H, H3), 7.01 (XX0 of AA0XX0, 2H,
H6), 6.97 (br d, 3JHH = 7.4 Hz, 1H, H2), 2.49 (s, 3H, H7), 2.10 (s,
9H, H8), 1.41 (d, 2JPH = 5.4 Hz, 9H, H10), 1.27 (d, 2JPH = 5.1 Hz,
9H, H9), 0.96 (apparent t, splitting = 2.8 Hz, 18H, H11) ppm.
Selected 1H{31P} NMR (500 MHz, C6D6): δ 7.45 (s, 1H, dCH),
2
28.9 Hz, 2P, Pax(CH3)3), -13.5 (dt, JPP = 28.9, 12.9 Hz, 1P,
Peq(CH3)3), -16.7 (dt, 2JPP = 27.6, 12.9 Hz, 1P, Peq(CH3)3) ppm.
1H NMR (THF-d8): δ7.57 (m, 1H, H1), 7.32 (m, 2H, H6), 7.23 (m,
2H, H7), 7.11 (m, 1H, H8), 6.91 (m, 1H, H4), 6.75 (m, 1H, H3),
6.59 (m, 1H, H2), 2.28 (apparent t, splitting = 2.6 Hz, 3H, H5),
1.59 (d, 2JPH = 5.5 Hz, 9H, H10), 1.54 (d, 2JPH = 5.1 Hz, 9H, H9),
0.96 (apparent t, splitting = 2.7 Hz, 18H, H11) ppm. 13C{1H,31P}
NMR (THF-d8): δ 182.8 (Ru-CR of C6H4), 160.8 (CipsoC6H4),
157.1 (C-CH3), 151.5 (Ru-C), 142.3 (C1), 130.8 (C6), 129.0 (C7),
128.9 (CipsoC6H5), 126.3 (C8), 122.8 (C2), 121.5 (C4), 121.1 (C3),
107.5 (CtC-Ph), 100.2 (CtC-Ph), 26.3 (C9), 25.7 (C10), 21.6
(C11), 18.4 (C5) ppm.
Low-Temperature NMR Studies. [Ru(η3-C(CtCC6H4-4-
Me)dC(H)C6H4-4-Me)(PMe3)4]BF4 (0.0292 g, 0.0372. mmol)
and dimethylmagnesium (0.0048 g, 0.0887 mmol) were placed in
an NMR tube fitted with a concentric Teflon valve. THF-d8 was
vacuum transferred into the tube, which was then placed into an
NMR probe that had been cooled to 238 K. Signals attributable
to 5, 6/7, and 8 were immediately apparent. Complex 5, trans-
Ru(CtCC6H4-4-Me)2(PMe3)4, has been previously reported25
and was identified on the basis of its 31P{1H} NMR spectrum.
Selected NMR data for 6, assigned as E- or Z-[Ru(Me)-
7.43 (d, JHH = 1.2 Hz, 1H, H1) ppm. 13C{1H,31P} NMR (125
4
MHz, C6D6): δ 181.9 (Ru-CR of C6H3), 158.2 (CipsoC6H3), 156.4
(dCH), 154.9 (Ru-C), 143.0 (C1), 135.7 (CC6H4CH3), 131.0 (C5),
130.4 (CC6H3CH3), 129.6 (C6), 126.0 (CipsoC6H4), 122.8 (C3), 122.4
(C2), 108.4 (CtC-Ar), 94.2 (CtC-Ar), 26.1 (C9), 25.4 (C10), 22.9
(C7), 21.7 (C11), 21.6 (C8) ppm.
[Ru(C(CtCPh)dC(Me)C6H4)(PMe3)4] (4d).
(η1-C(CtCC6H4-4-Me)dC(H)C6H4-4-Me)(PMe3)4]:
31P{1H}
3
NMR: δ -3.02 (dd, JPP = 22.2, 29.8 Hz, 2P, Pax), -6.91 (dt,
3JPP = 17.1, 29.8 Hz, 1P, Peq), -13.2 (dt, 3JPP = 17.1, 22.2 Hz, 1P,
4
Peq) ppm. 1H NMR: δ 6.62 (d, JPH = 5.0 Hz, dCH), 1.33 (m,
Pax(CH3)3), 1.36(d, 2JPH =5.6Hz, Peq(CH3)3), 1.48(d, 2JPH =5.4
Hz, Peq(CH3)3), -0.46 (m, Ru-CH3) ppm. 13C{1H,31P} NMR:
δ 144.6 (dCH), 138.7, 126.9, 106.9, 24.1 (Peq(CH3)3), 20.9
(Pax(CH3)3), 22.8 (Peq(CH3)3), -3.81 (Ru-CH3) ppm. Selected
A solution of [Ru(η3-C(CtCPh)dC(Me)Ph)(PMe3)4]OTf
(0.2685 g, 0.348 mmol) in THF (20 mL) was treated with Me2Mg
(2.0 mL, 0.15 M in THF, 0.30 mmol). The mixture was stirred at
room temperature for 1 h before the volatiles were removed
NMR data for 8, assigned as [Ru-C(dC(H)C6H4Me)C(H)dCC6-

Article
Organometallics, Vol. 28, No. 18, 2009 5521
H4Me(PMe3)4]: 31P{1H} NMR: δ 0.47 (dd, 3JPP = 20.8, 30.3 Hz,
=
at calculated positions, and all non-hydrogen atoms were re-
fined anisotropically. Cystallographic data for the structure of
4a are summarized in Table 2.
2P, Pax), -9.59 (dt, 3JPP = 12.8, 30.3 Hz, 1P, Peq), -12.5 (dt, 3JPP
1
4
12.8, 20.8 Hz, 1P, Peq) ppm. H NMR: δ 6.27 (d, JPH = 7.0
Hz, dCH),1.46(m,Pax(CH3)3),1.41(d,2JPH =5.1Hz,Peq(CH3)3),
1.27 (t, JPH = 4.0 Hz, C-CH3), 1.12 (d, 2JPH = 4.5 Hz, Peq(CH3)3)
ppm. 13C{1H,31P} NMR: δ 163.3 (Ru-C), 145.9 (C-CH3), 124.7
(dCH), 25.1 (Peq(CH3)3), 23.8 (Peq(CH3)3), 21.0 (Pax(CH3)3), 19.7
(C-CH3) ppm. Upon warming to room temperature, signals attrib-
uted to 6 gradually diminished, while resonances attributed to 4c
increased.
A suitable single crystal of 4d was selected under the polariz-
ing microscope (Leica M165Z) and was glued to a glass fiber
with a dot of silicon paste that fixed the crystal firmly upon
freezing at the temperature of data collection (150 K). The
intensities were measured on a Bruker kappa APEX-II CCD
diffractometer with low temperature at the crystal maintained
using an Oxford Cryostream 700 system. Upon obtaining an
initial refinement of unit cell parameters, the data collection
strategy achieved a redundancy of at least 4 throughout the
X-ray Crystallography. A suitable single crystal of 4a was
selected under the polarizing microscope (Prior Scientific,
Zoommaster) and was mounted on a glass fiber with the use
of a dot of silicon grease. Intensities were measured on a Bruker
Nonius X8 Apex-II diffractometer equipped with graphite-
˚
resolution range (inf-0.80 A) at 10 s exposure time per frame
making use of the kappa offsets on the four-circle goniometer
geometry. The data integration and reduction with the multi-
scan absorption correction method was carried out using the
APEX2 suite of software.39 The structure was solved by direct
methods using SHELXS-9740 and was refined by the full-matrix
least-squares refinement program SHELXL40 to the final R
value of 0.027 (wR 0.111) for 5381 reflections. Crystallographic
data for the structure of 4d are summarized in Table 2.
˚
monochromated Mo KR radiation (λ = 0.71073 A) and oper-
ating at a low temperature of 100(2) K with an Oxford Cryo-
stream system. Upon collecting intensities, an average
redundancy of >11 was obtained for the resolution range of
˚
inf-0.60 A with a 10 s exposure time over a range of omega and
phi scans. The data integration and reduction with the multi-
scan absorption correction method was carried out using the
APEX2 suite of software.39 The structure was solved with direct
methods and full-matrix least-squares refinements by using the
SHELXTL-97 program package40 to the final R value of 0.0304
(wR 0.0548) for 10 809 reflections. Hydrogen atoms were placed
Acknowledgment. The authors thank the Australian
Research Council for funding.
Supporting Information Available: A CIF file giving crystal-
lographic data. This material is available free of charge via the
Internet at http://pubs.acs.org.
(39) APEX2; Bruker Bruker Analytical X-ray Instruments Inc.: Madison,
WI, 2007.
(40) Sheldrick, G. M. Acta Crystallogr., Sect. A 2008, 64, 112–122.