Tethered indenyl-phosphine complexes of ruthenium(II) via reductive elimination of a ruthenium(IV) complex

Article abstract of DOI:10.1021/om070225j

The Ru(IV) phosphine complex [(η³,η³-C ₁₀H₁₆)RuCl₂(κ¹P-LH)] (2) was synthesized from the reaction of [(η³,η³-C ₁₀H₁₆)RuCl₂]₂ with [(C ₉H₇)(CH₂)₂PPh₂] (LH). Treatment of 2 with acid led to halide labilization to give [(η ³η³-C₁₀H₁₆)RuCl(CH ₃CN)(κ¹-LH)]⁺ [2a]⁺. Reductive elimination of the bis(allyl) ligand in 2 was effected in the reaction of 2, a two- or four-electron ligand (DD), Na₂CO₃, and KPF ₆ in EtOH, resulting in the isolation of PF₆ salts of monocationic tethered indenyl Ru species, [(η,κ¹P-L)Ru(DD)] (3, DD = 1,5-cyclooctadiene (COD); 6, DD = 2,2′-bipyridyl (bpy)), and neutral tethered indenyl Ru complexes (4, DD = (PPh₃)Cl; 5, DD = (PPh₃)H). In addition to [6]PF₆, [(κ¹P- LH)Ru(bpy)₂Cl]PF₆, [7]PF₆, was an additional product in the bpy reaction, as was {[(κ¹P-LH)Ru(bpy)Cl] ₂(μ-Cl)₃}PF₆, [8]-PF₆, when Na₂CO₃ was replaced by Li₂CO₃. In the presence of HC1, [6]⁺ was found to convert to [8]⁺, while [8]⁺ was converted to [7]⁺ with bpy and KPF ₆. The reaction of 2 with acetylacetone (acacH) gave a high yield of an unusual complex, [(η²,κ¹P-LH)Ru(acac) ₂] (9), in which LH adopts a rare η², κ¹P-coordination mode. The new compounds were all spectroscopically characterized, with 2, 2a, 3, 4, and 9 also determined by single-crystal X-ray diffraction analyses.

Full text of DOI:10.1021/om070225j

3352
Organometallics 2007, 26, 3352-3361
Tethered Indenyl-Phosphine Complexes of Ruthenium(II) via
Reductive Elimination of a Ruthenium(IV) Complex
Sin Yee Ng, Geok Kheng Tan, Lip Lin Koh, Weng Kee Leong,* and Lai Yoong Goh*
Department of Chemistry, National UniVersity of Singapore, Kent Ridge, Singapore 119260
ReceiVed March 9, 2007
The Ru(IV) phosphine complex [(η3,η3-C10H16)RuCl2(κ1P-LH)] (2) was synthesized from the reaction
of [(η3,η3-C10H16)RuCl2]2 with [(C9H7)(CH2)2PPh2] (LH). Treatment of 2 with acid led to halide labilization
to give [(η3,η3-C10H16)RuCl(CH3CN)(κ1P-LH)]+ [2a]+. Reductive elimination of the bis(allyl) ligand in
2 was effected in the reaction of 2, a two- or four-electron ligand (DD), Na2CO3, and KPF6 in EtOH,
resulting in the isolation of PF6 salts of monocationic tethered indenyl Ru species, [(η5,κ1P-L)Ru(DD)]
(3, DD ) 1,5-cyclooctadiene (COD); 6, DD ) 2,2′-bipyridyl (bpy)), and neutral tethered indenyl Ru
complexes (4, DD ) (PPh3)Cl; 5, DD ) (PPh3)H). In addition to [6]PF6, [(κ1P-LH)Ru(bpy)2Cl]PF6,
[7]PF6, was an additional product in the bpy reaction, as was {[(κ1P-LH)Ru(bpy)Cl]2(µ-Cl)3}PF6, [8]-
PF6, when Na2CO3 was replaced by Li2CO3. In the presence of HCl, [6]+ was found to convert to [8]+,
while [8]+ was converted to [7]+ with bpy and KPF6. The reaction of 2 with acetylacetone (acacH) gave
a high yield of an unusual complex, [(η2,κ1P-LH)Ru(acac)2] (9), in which LH adopts a rare η2,κ1P-
coordination mode. The new compounds were all spectroscopically characterized, with 2, 2a, 3, 4, and
9 also determined by single-crystal X-ray diffraction analyses.
Scheme 1
Introduction
Compared to their parent Cp/Ind systems, organometallic
complexes containing tethered cyclopentadienyl (η5-C5H5, Cp)
or indenyl (η5-C9H7, Ind) ligands can exhibit quite different
stability and reactivity characteristics,1 including catalytic activ-
ity.2 This has stimulated much work directed at the synthesis
of ligands with variations on the Cp ring, the spacer, the
heteroatom donor, and its substituent.1e,3-6 Of keen interest is
the combined effect of both metal-centered chirality and planar-
chirality of Cp/Ind ligands on diastereoselectivity in reac-
tions.5,7,8 Planar-chirality can be induced by nonsymmetrical ring
substitution, advantageously with a tethered ligand for asym-
metric syntheses, or by an optically active substituent (e.g.,
neomenthyl or neoisomenthyl) in the Cp ring or the tether.5b,c
Since half-sandwich ruthenium complexes containing phos-
phine ligands are known to possess high catalytic activity for
many reactions,9 tethered Cp analogues have been of special
interest. Indeed, the literature to date contains many examples
of such phosphine-containing ruthenium(II) species, originating
from the ruthenium precursor RuCl2(PR3)3 (Scheme 1).1b,3,5a,6
Recently, Takahashi reported the synthesis of tethered Cp-
pyridine and -phosphine Ru(II) complexes containing aceto-
nitrile co-ligands via displacement of a labile benzene ligand
(Scheme 2a,c).7 These are useful precursors to desired deriva-
tives, wherein the labile acetonitrile ligands are substituted by
bidentate ligands such as 2,2′-bipyridine and dithiocarbamate
(Scheme 2b,d). Shortly after, Salzer and co-workers prepared
analogous acetonitrile complexes from the reactions of the
dimeric ruthenium(IV) complex [(η3,η3-C10H16)RuCl2]2 (1) in
EtOH in the presence of CH3CN and Li2CO3; the reaction
occurred either via direct displacement of the 2,7-dimethyloc-
tadienediyl ligand with a Cp-linked phosphine ligand (Scheme
* Corresponding author. E-mail: chmgohly@nus.edu.sg; chmlwk@
nus.edu.sg. Fax: (+65) 6779 1691.
(1) (a) Becker, E.; Mereiter, K.; Puchberger, M.; Schmid, R.; Kirchner,
K.; Doppiu, A.; Salzer, A. Organometallics 2003, 22, 3164. (b) Trost, B.
M.; Vidal, B.; Thommen, M. Chem.-Eur. J. 1999, 5, 1055. (c) Foerstner,
J.; Kakoschke, A.; Stellfeldt, D.; Butenscho¨n, H.; Wartchow, R. Organo-
metallics 1998, 17, 893. (d) Casey, C. P.; Czerwinske, C. J.; Fusie, K. A.;
Hayashi, R. K. J. Am. Chem. Soc. 1997, 119, 3971. (e) Kataoka, Y.; Saito,
Y.; Nagata, K.; Shibahara, A.; Tani, K. Chem. Lett. 1997, 621. (f) Wang,
S.; Li, H.-W.; Xie, Z. Organometallics 2004, 23, 2469. (g) Wang, S.; Li,
H.-W.; Xie, Z. Organometallics 2004, 23, 3780.
(2) (a) Gareau, D.; Sui-Seng, C.; Groux, L. F.; Brisse, F.; Zargarian, D.
Organometallics 2005, 24, 4003. (b) Groux, L. F.; Zargarian, D. Organo-
metallics 2003, 22, 3124. (c) Groux, L. F.; Zargarian, D. Organometallics
2001, 20, 3811. (d) Buil, M. L.; Esteruelas, M. A.; Lo´pez, A. M.;
Concepcio´n Mateo, A; On˜ate, E. Organometallics 2007, 26, 554.
(3) (a) Siemeling, U. Chem. ReV., 2000, 100, 1495. (b) Butenscho¨n, H.
Chem. ReV. 2000, 100, 1527. (c) Mu¨ller, C.; Vos, D.; Jutzi, P. J. Organomet.
Chem. 2000, 600, 127. (d) Jutzi, P.; Redeker, T. Eur. J. Inorg. Chem. 1998,
663. (e) Jutzi, P.; Siemeling, U. J. Organomet. Chem. 1995, 500, 175. (f)
Jutzi, P.; Dahlaus, J. Coord. Chem. ReV. 1994, 137, 179.
(4) (a) Ciruelos, S.; Doppiu, A.; Englert, U.; Salzer, A. J. Organomet.
Chem. 2002, 663, 183. (b) Doppiu, A.; Englert, U.; Peters, V.; Salzer, A.
Inorg. Chim. Acta 2004, 357, 1773.
(5) (a) Kataoka, Y.; Saito, Y.; Nagata, K.; Shibahara, A.; Tani, K. Chem.
Lett. 1995, 833. (b) Kataoka, Y.; Iwato, Y.; Yamagata, T.; Tani, K.
Organometallics 1999, 18, 5423. (c) Brookings, D. C.; Harrison, S. A.;
Whitby, R. J.; Crombie, B.; Jones, R. V. H. Organometallics 2001, 20,
4574.
(7) (a) Dodo, N.; Matsushima, Y.; Uno, M.; Onitsuka, K.; Takahashi, S.
J. Chem. Soc., Dalton Trans. 2000, 35. (b) Onitsuka, K.; Ajioka, Y.;
Matsushima, Y.; Takahashi, S. Organometallics 2001, 20, 3274. (c)
Matsushima, Y.; Onitsuka, K.; Takahashi, S. Organometallics 2004, 23,
3763. (d) Matsushima, Y.; Onitsuka, K.; Takahashi, S. Organometallics
2005, 24, 2747.
(8) (a) Kataoka, Y.; Shibahara, A.; Saito, Y.; Yamagata, T.; Tani, K.
Organometallics 1998, 17, 4338. (b) Kataoka, Y.; Iwato, Y.; Shibahara,
A.; Yamagata, T.; Tani, K. Chem. Commun. 2000, 841.
(9) (a) Trost, B. M. Acc. Chem. Res. 2002, 35, 695, and references therein.
(b) Trost, B. M.; Frederikson, M. U.; Rudd, M. T. Angew. Chem., Int. Ed.
2005, 44, 6630.
(6) Baker, R. W.; Luck, I. J.; Turner, P. Inorg. Chem. Commun. 2005,
8, 817.
10.1021/om070225j CCC: $37.00 © 2007 American Chemical Society
Publication on Web 06/01/2007

Tethered Indenyl-Phosphine Complexes of Ruthenium(II)
Organometallics, Vol. 26, No. 14, 2007 3353
Scheme 2
Scheme 310
Scheme 4
proved unsuccessful, giving an inseparable complex mixture of
products. We next reacted 1 with LH at ambient temperature
for 4 h. However, unlike Salzer’s reaction with CpHCH2CH-
(R)PPh2 or CpHCH(R′)CH2PPh2,10a an Ind-P tethered complex
was not formed, but instead only a phosphine derivative of 1,
viz., complex 2, in high yield (Scheme 5). It appears probable
that the presence of bulky substituents (R or R′) on the spacer
carbons of the difunctional ligand predisposes the ligand toward
tethering.
3a)10a or the reaction of the [(η5-C7H11)2HRu]+ (AH)+ salt
(obtained by protonation of A)11 with the Cp-linked phosphine
ligand in refluxing CH3CN (Scheme 3(b)).10b
In comparison to Cp-tethered transition metal complexes, their
indenyl analogues are scarce, with those of Ni,2 Rh,1e,5,8,12 and
Ir12c being representative (Scheme 4). Enders had reported a
stable complex of Cr(III) containing the Cp/Ind-N tether (N )
8-quinoline).12d
A recently reported Ru complex bears a tethered indenyl
ligand containing an amino group through constrained coordina-
tion.6 The relative scarcity of such tethered compounds is
undoubtedly related to the lack of viable synthetic strategies.
This study attempts to address the problem, and the results are
described herein.
We therefore attempted to labilize the bis(allyl) ligand in 2
with an acid, the noncoordinating triflic acid, borrowing on the
methodology of Werner and Stone in the use of carboxylic acids
to labilize ruthenium-allyl bonds.13 However, this reaction led
only to the precipitation of the triflic salt of [(η3,η3-C10H16)RuCl-
(CH3CN)(κ1P-LH)]+, [2a]+, a solvento derivative of 2 (Scheme
6). The intact bis(allyl) ligand indicates its inertness to proto-
nation. It is likely that further chloride substitution in [2a]CF3-
SO3 had been prevented by its insolubility in the solvent
medium. A double dehalogenation at Ru had been postulated
to be essential for C5H6 (CpH) or C9H8 (IndH) to coordinate to
the metal.11
1
The H NMR spectra of 2 and [2a]+ are consistent with the
presence of LH and the (η3,η3-C10H16) ligand. The 31P NMR
spectrum of 2 shows a signal at δ 18.9, a typical chemical shift
for a coordinated phosphine ligand. The 31P signal of [2a]+ is
found in a lower field at δ 22.2.
Results and Discussion
Synthesis. We tried route (b) in Scheme 3 using the Ind-
phosphine ligand IndHCH2CH2PPh2 (LH).5b The reaction
(10) (a) Doppiu, A.; Englert, U.; Salzer, A. Inorg. Chim. Acta 2003,
350, 435. (b) Doppiu, A.; Salzer, A. Eur. J. Inorg. Chem. 2004, 2244.
(11) Bauer, A.; Englert, U.; Geyser, S.; Podewils, F.; Salzer, A.
Organometallics 2000, 19, 5471.
(12) (a) Kataoka, Y.; Shibahara, A.; Yamagata, T.; Tani, K. Organo-
metallics 2001, 20, 2431. (b) Kataoka, Y.; Nakagawa, Y.; Shibahara, A.;
Yamagata, T.; Mashima, K.; Tani, K. Organometallics 2004, 23, 2095. (c)
Kataoka, Y.; Shimada, K.; Goi, T.; Yamagata, T.; Mashima, K.; Tani, K.
Inorg. Chim. Acta 2004, 357, 2965. (d) Enders, M.; Ferna´ndez, P.; Ludwig,
Pritzkow, H. Organometallics 2001, 20, 5005.
The ORTEP diagrams of 2 and [2a]+ are shown in Figure 1
and 2, respectively, and selected bond lengths and bond angles
are given in Table 1. The X-ray structure of 2 shows that there
are two independent molecules and one ether molecule in the
(13) See for instance: (a) Werner, H.; Fries, G.; Woberndo¨rfer, B. J.
Organomet. Chem. 2000, 607, 182. (b) Dossett, S. J.; Li, S.; Stone, F. G.
A. J. Chem. Soc., Dalton Trans. 1993, 1585.

3354 Organometallics, Vol. 26, No. 14, 2007
Ng et al.
Scheme 5
Scheme 6
Table 1. Selected Bond Lengths and Angles for 2 and [2a]+ a
bond length (Å)
2
[2a]+
bond angles (deg)
2
[2a]+
Ru(1)-P(1)
Ru(1)-Cl(1)
Ru(1)-X
2.4144(11)
2.4050(16)
D(1)-Ru(1)-D(2)
D(1)-Ru(1)-Cl(1)
D(1)-Ru(1)-X
D(1)-Ru(1)-P(1)
D(2)-Ru(1)-Cl(1)
D(2)-Ru(1)-X
D(2)-Ru(1)-P(1)
Cl(1)-Ru(1)-X
Cl(1)-Ru(1)-P(1)
P(1)-Ru(1)-X
Ru(1)-P(1)-C(1)
C(2)-C(1)-P(1)
130.51
92.54
X ) Cl(2), 88.23
114.63
88.02
X ) Cl(2), 92.01
114.85
X ) Cl(2), 174.00(4)
89.71(4)
X ) Cl(2), 84.56(4)
115.82(15)
130.87
94.08
X ) N(1), 88.03
115.08
89.77
X ) N(1), 91.72
114.04
X ) N(1), 175.65(15)
84.42(6)
X ) N(1), 91.24(15)
114.6(2)
2.4179(11)
X ) Cl(2), 2.4331(11)
2.216(4)
2.295(4)
2.280(4)
2.277(4)
2.275(4)
2.231(4)
2.011
2.4094(18)
X ) N(1), 2.031(6)
2.274(6)
2.299(6)
2.252(6)
2.201(6)
2.273(7)
2.278(6)
2.025
Ru(1)-C(12)
Ru(1)-C(13)
Ru(1)-C(14)
Ru(1)-C(17)
Ru(1)-C(18)
Ru(1)-C(19)
Ru(1)-D(1)
Ru(1)-D(2)
C(3)-C(4)
2.006
2.003
1.326(7)
1.469(6)
1.490(7)
1.505(8)
1.317(11)
1.501(12)
1.567(16)
1.473(18)
115.2(3)
115.3(4)
C(3)-C(11)
C(4)-C(5)
C(5)-C(6)
a D(1) and D(2) are the centroids of atoms C(12), C(13), C(14) and C(17), C(18), C(19), respectively.
Figure 1. ORTEP diagram of 2 (50% probability thermal el-
lipsoids, hydrogen atoms and Ph rings have been omitted for
clarity).
Figure 2. ORTEP diagram of 2a cation (50% probability thermal
ellipsoids, hydrogen atoms and Ph rings have been omitted for
clarity).
asymmetric unit, while the asymmetric unit of [2a]CF3SO3
contains one molecule of [2a]+ and a disordered CF3SO3- anion.
The molecular structures of 2 and [2a]+ are very similar to those
of other reported bis(allyl) Ru(IV) complexes, e.g., RuCl2(η3,η3-
C10H16)P (P ) Ph2PNHC6H4PPh2,14 Ph2PNHNHpy15) and RuCl-
(η3,η3-C10H16)(CH3CN)2.16 The coordination geometries around
the Ru center in both 2 and [2a]+ are distorted trigonal
pyramidal, with bis(allyl) and the κ1P-LH ligand occupying the
equatorial positions. It was noticed that the phosphorus atom is
(14) Aucott, S. M.; Slawin, A. M. Z.; Woolins, J. D. J. Organomet. Chem.
1999, 582, 83.
(15) Slawin, A. M. Z.; Wheatley, J.; Wheatley, M. V.; Woolins, J. D.
Polyhedron 2003, 22, 1397.
(16) Cox, D. N.; Small, R. W. H.; Roulet, R. J. Chem. Soc., Dalton
Trans. 1991, 2013.

Tethered Indenyl-Phosphine Complexes of Ruthenium(II)
Organometallics, Vol. 26, No. 14, 2007 3355
Scheme 7
Scheme 8
angle (HA) ) 5.1°, and (iii) fold angle (FA) ) 8.3°, indicating
that the indenyl ligand is coordinated to the Ru center via a
distorted η5-mode.19
The reactions of 2 with N-, P-, and O-donor ligands in the
presence of 1 equiv of Na2CO3 in EtOH have been studied.
The reaction with PPh3 gave a mixture of [(η5,κ1P-L)Ru(PPh3)-
Cl] (4) and [(η5,κ1P-L)Ru(PPh3)H] (5) (isolated in ca. 4:1
relative yield). Both 4 and 5 were obtained in only one
diastereomeric form each. The formation of 5 was hindered by
reducing the amount of Na2CO3; at zero or 0.5 mol equiv to 2,
none of 5 was formed, while the yield of 4 increased to 82%.
A plausible formation pathway is proposed in Scheme 9, in
which Na2CO3 is required for the functions of chloride and
proton abstraction (routes (a) and (b), respectively). A separate
reaction showed that complex 5 can be obtained in high yield
almost equidistant from D1 and D2, the centroids of atoms
C(12), C(13), C(14) and C(17), C(18), C(19), respectively, in
2, while the phosphorus atom is closer to D2 than to D1 in
[2a]+. The lack of symmetry in the bis(allyl) ligand in [2a]+ is
1
reflected in the H NMR spectroscopic data.
Subsequent to the above negative synthetic outcomes, we
attempted reductive elimination of the bis(allyl) ligand in the
presence of two- or four-electron donor ligands and a base or a
halogen abstractor (Scheme 7). Indeed, we found that the
reaction of 2 with 1,5-cyclooctadiene (COD) in the presence of
AgPF6 in EtOH solution proceeded at room temperature to give
[(η5,κ1P-L)Ru(COD)]PF6, [3]PF6, in high yield. The same result
was obtained by refluxing 2 with COD in EtOH, in the presence
of finely ground Na2CO3 and KPF6 (Scheme 8). In fact this
latter set of reagents has proven more useful, as it is compatible
with different classes of incoming ligands, e.g., phosphine
donors such as PPh3, nitrogen donors such as 2,2′-bipyridyl,
and oxygen donors such as acac, in which cases the Ag+ ion
interferes. Additionally it was observed that the particle size of
the base was a crucial factor on the yield, consistent with the
heterogeneous nature of the reaction.17
The 1H NMR signals for the COD ligand in [3]PF6 appear in
the range δ 0.66-2.20 for CH2 and δ 3.52-4.04 for CH, while
the protons of the ethylene side arm resonate as two multiplets
in the range δ 2.32-2.89. The 31P signal appears at δ 67.7,
which is within the low-field range [δ 52-88] reported for the
tethered complex [(η5,κ1P-Cp(CH2)2PPh2)Ru(CH3CN)2]PF6.10b
The molecular structure of [3]+ showing the η5,κ1P-coordina-
tion mode of L is illustrated in Figure 3. There is no significant
difference between its bond parameters and those of its Ind
analogue, [(η5-Ind)Ru(COD)(py)]BF4.18 The slip-fold parameters
for [3]PF6 are (i) slip distortion (∆) ) 0.122 (7) Å, (ii) hinge
Figure 3. ORTEP diagram of [3]+ (50% probability thermal
ellipsoids, hydrogen atoms and Ph rings have been omitted for
clarity). Selected bond lengths (Å) and angles (deg). Ru(1)-P(1)
) 2.3995(18); Ru(1)-C(12) ) 2.223(6); Ru(1)-C(19) ) 2.214-
(6); Ru(1)-C(15) ) 2.212(7); Ru(1)-C(16) ) 2.221(7); Ru(1)-
C* ) 1.911; C*-Ru(1)-C(12) ) 115.62; C*-Ru(1)-C(15) )
112.24; C*-Ru(1)-C(16) ) 141.12; C*-Ru(1)-C(19) ) 137.55;
C*-Ru(1)-P(1) ) 107.88; C(15)-Ru(1)-C(16) ) 37.2(2); C(12)-
Ru(1)-C(19) ) 36.4(3); Ru(1)-P(1)-C(11) ) 100.0(2) (C* )
centroid of the five-membered ring, comprising C(1), C(2), C(3),
C(8), and C(9)).
(17) Salzer, A.; Bauer, A.; Geyser, S.; Podewils, F. Inorg. Synth. 2004,
34, 59.
(18) Alvarez, P.; Gimeno, J.; Lastra, E.; Garc´ıa-Granda, S.; Van der
Maelen, J. F.; Bassetti, M. Organometallics 2001, 20, 3762.

3356 Organometallics, Vol. 26, No. 14, 2007
Ng et al.
Scheme 9
Figure 4. Molecular structure of 4.
by refluxing 4 with NaOMe (pathway (d)). Hydride formation
in thiolate substitution reactions of (Ind)Ru(dppf)Cl had been
shown to be effected by the generation of methoxide via an
equilibrium between thiolate RS- and MeOH;20a indeed, the
synthesis of (Cp/Ind)Ru hydrides from halide precursors via
methoxide intermediates is a standard methodology.20b-d.
The 1H NMR spectrum of 4 shows five sets of multiplets in
the range δ 1.42-3.22, assigned to the protons of the ethylene
side arm of the L ligand. On the basis of a 2D-COSY NMR
measurement, the two singlets at δ 2.26 and 4.87 are assigned
to the protons on the five-membered ring of L. The upfield
chemical shift (δ 2.26) of the protons on the Cp ring of the
indenyl ligand had been observed at δ 3.56 in the tethered
indenyl Ni complex, [(η5-Ind(CH2)2(CHdCH2))Ni(PPh3)Cl].2a,21
This is consistent with the X-ray structural analysis (see Figure
4), which shows the indenyl proton, H12, pointing directly
toward the center of the phenyl ring and hence subjected to
shielding by the ring current of the phenyl ring of PPh3.
and [8]PF6 and its absence in [6]PF6. A very plausible rationale
for the difference in the two situations therefore lies in the
greater availabilty of chloride ions in the Li2CO3 case, arising
from the higher solubility of LiCl versus NaCl in EtOH. This
also explains the additional formation of species [8]PF6 with
even higher Cl- content. The supply of Cl- from HCl was found
to convert complex [6]PF6 completely to complex [8]PF6,
(Scheme 10(iii)), but this conversion could not be effected with
NaCl. [6]PF6 with HCl converted to a mixture of complexes
[7]PF6 and [8]PF6 in the added presence of 1.5 molar equiv of
bpy (Scheme 10(iv)). In addition it was found that in the
presence of 1 molar equiv of bpy and KPF6, [8]PF6 was
transformed to [7]PF6 (Scheme 10(v)). It was also observed that
the reaction of 2 with a 4-fold excess of bpy resulted in total
displacement of all the ligands, giving [Ru(bpy)3](PF6)2 as the
sole product. In context, we note that Salzer and co-workers
had observed a marked effect of the carbonate bases of group
1 metals (Li > Na > K) on the yield of the sandwich bis(dienyl)
complex [(η5-C7H11)2Ru] (A) from the reaction of 1 with
dimethylpentadiene; this had been ascribed to solubility differ-
ences of the solid bases in the reaction medium.11
1
The H NMR spectrum of 5 shows a characteristic hydride
signal at δ -13.9 as a doublet of a doublet, consistent with
coupling to two P atoms of the phosphane ligands. The protons
of the indenyl Cp ring resonate in the “normal” range at δ 4.78
and 5.48. This observation implies that the orientation of the
Cp ring in 5 is different from that in 4, but unfortunately X-ray
crystal structural data could not be obtained.
The reaction of 2 with 1 molar equiv of 2,2′-bipyridyl (bpy)
in the presence of Na2CO3 and KPF6 led to the formation of
[(η5,κ1P-L)Ru(bpy)]PF6 ([6]PF6) and [(κ1P-LH)Ru(bpy)2Cl]PF6
([7]PF6) in ca. 2:1 molar ratio (Scheme 10(i)). An inverse
relative yield (i.e., 1:2) of species [6]PF6 and [7]PF6, was
obtained when Na2CO3 was replaced by Li2CO3; in addition, a
new product, {[(κ1P-LH)Ru(bpy)Cl]2(µ-Cl)3}PF6, [8]PF6, was
formed (Scheme 10(ii)). The glaring difference in the composi-
tion of these complexes is the presence of chloride in [7]PF6
The proposed formulations of species [6]PF6, [7]PF6, and [8]-
PF6 were based on microanalytical and spectroscopic evidence.
The coordination mode of L and LH in the cationic complexes
[6]PF6, [7]PF6, and [8]PF6 can be determined by their resonances
in the 1H NMR spectra. The protons of the Cp ring of (η5,κ1P-
L)in [6]PF6 appear at δ 5.21 and 5.53, indicating the aromaticity
at the Cp ring, while the protons of the five-membered ring of
(κ1P-LH) in species [7]PF6 and [8]PF6 are found at δ 6.10 (for
the “-ene” proton) and δ 3.23 (for the sp3-protons). The 31P
NMR spectrum also gave significant insight into the coordina-
tion mode of the ligand as the 31P signal of (η5,κ1P-L) in [6]-
PF6 resonates at δ 61.7, which is at lower field than the 31P
signal of (κ1P-LH) in [7]PF6 (δ 39.5) and [8]PF6 (δ 54.5). Their
mass spectra showed their mother ion peaks. While the isotopic
distribution patterns of the signals showed that [6]PF6 and [7]-
PF6 are mononuclear species, that of [8]PF6 indicated a dinuclear
species.
(19) For indenyl complexes containing undistorted η5 rings: ∆ ) 0.03
Å; HA ) 2.5 °; FA ) 4.4°; for those containing distorted η5 rings: ∆ )
0.11-0.42 Å; HA ) 7-14°; FA ) 6-13°; and for those wherein the five-
membered ring is η3-coordinated: ∆ ) 0.8 Å; FA ) 28°. See: Kakkar, A.
K.; Taylor, N. J.; Marder, T. B.; Shen, J. K.; Hallinan, N.; Basolo, F. Inorg.
Chim. Acta 1992, 198-200, 219.
(20) (a) Ng, S. Y.; Leong, W. K.; Goh, L. Y.; Webster, R. D. Eur. J.
Inorg. Chem. 2007, 463. (b) Bruce, M. I.; Humphrey, M. G.; Swincer, A.
G.; Wallis, R. C. Aust. J. Chem. 1984, 37, 1747. (c) Bassetti, M.; Casellato,
P.; Gamasa, M. P.; Gimeno, J.; Gonza´lez-Bernardo, C.; Mart´ın-Vaca, B.
Organometallics 1997, 16, 5470. (d) Gamasa, M. P.; Gimeno, J.; Gonza´lez-
Bernardo, C.; Mart´ın-Vaca, B.; Borge, J.; Garcia-Granda, S. Inorg. Chim.
Acta 2003, 347, 181.
The reaction of 2 with 1 molar equiv of acetyl acetone in the
presence of 2 molar equiv of Na2CO3 gave a multicomponent
product mixture from which complex [(η2,κ1P-LH)Ru(acac)2]
(9) was isolated in 38% yield (Scheme 11). A repeat experiment
(21) Zargarian, D. Coord. Chem. ReV. 2002, 233-234, 157.

Tethered Indenyl-Phosphine Complexes of Ruthenium(II)
Organometallics, Vol. 26, No. 14, 2007 3357
Scheme 10
Scheme 11
which Ru is coordinated to P and the terminal alkene of a
phosphino ligand;24 the phosphine is homoallylic in 9 but allylic
in the latter. The C(1)-C(9) bond length (1.392(4) Å, clearly
of double-bond character, is close to that in C (1.391(8) Å)24
but longer than those in coordinated unsubstituted ethenes in B
and its monoethene derivatives (range 1.35(1)-1.37(3) Å).23
The Ru(1)-P(1) distance is substantially shorter (∆ ≈ 0.06-
0.09 Å) than the analogous distance in C.24 The Ru(1)-C(1)
distance is comparable to the equivalent distances in B;23
however the Ru(1)-C(9) bond is significantly longer (∆ )
using the correct stoichiometric amount of acetyl acetone to 2
in the presence of an appropriate molar equivalent of Na2CO3
gave an increased yield of 9 (78%) from a cleaner product
mixture. In complex 9, the Ru(II) center is coordinated to two
chelating acac ligands and an LH ligand in an uncommon
η2,κ1P-coordination mode.
Complex 9 was characterized by single-crystal X-ray dif-
fraction analysis. The asymmetric unit contains two independent
tilted molecules, the structures of which are very similar. This
is shown in Figure 5, with selected bond parameters for one of
the molecules. The Ru(II) center adopts a pseudo-octahedral
geometry, with coordination to the four O atoms of two acac
ligands, a P donor atom, which with O(4) occupies equatorial
positions, and an “ene” C(1)-C(9) moiety taking up the sixth
position, which is axial and trans to O(3). The (η2,κ1P-LH)
coordination mode to Ru is rare and had been observed before
only in the (η2,κ1N-Ind-quinolyl) tethered complexes of Rh(I)
and Mo(0).22 Ethene complexes of acac-containing Ru(II) are
known, e.g., cis-Ru(acac)2(η2-C2H4)2 (B) and derivatives thereof.23
The bonding mode in 9 bears a slight resemblance to that found
in [(η5-Ind)Ru(κ3(P,C,C)-Ph2P(CH2CHdCH2))(PPh3)]+ (C), in
Figure 5. ORTEP diagram of 9 (50% probability thermal el-
lipsoids, hydrogen atoms omitted) and selected bond lengths (Å)
and angles (deg): Ru(1)-O(1) ) 2.0563(19); Ru(1)-O(2) )
2.1067(18); Ru(1)-O(3) ) 2.069(2); Ru(1)-O(4) ) 2.0670(19);
Ru(1)-P(1) ) 2.2495(8); Ru(1)-C(1) ) 2.186(3); Ru(1)-C(9) )
2.252(3); C(1)-C(9) ) 1.392(4); C(1)-C(2) ) 1.513(4); O(1)-
Ru(1)-O(2) ) 90.23(8); O(3)-Ru(1)-O(4) ) 89.53(9); C(1)-
Ru(1)-C(9) ) 36.53(10); C(1)-C(9)-C(8) ) 107.3(2); C(1)-
C(9)-C(10) ) 128.2(3); C(8)-C(9)-C(10) ) 119.4(2); C(9)-
C(1)-C(2) ) 110.7(2); C(9)-C(1)-Ru(1) ) 74.32(16); C(2)-
C(1)-Ru(1) ) 113.82(19).
(22) Enders, M.; Ferna´ndez, P.; Kaschke, M.; Kohl, G.; Ludwig, G.;
Pritzkow, H.; Rudolph, R. J. Organomet. Chem. 2002, 641, 81.
(23) Bennett, M. A.; Byrnes, M. J.; Willis, A. C. Organometallics 2003,
22, 1018.

3358 Organometallics, Vol. 26, No. 14, 2007
Ng et al.
complexes containing COD, PPh3, and 2,2′-bipyridyl ligands.
While L adopts the expected η5,κ1P-coordination mode in
complexes [3]+, 4, 5, and [6]+, it was also found to coordinate
either via a κ1P-LH, as in [7]+ and [8]+, or via a rare η2,κ1P-
LH coordination mode, as found in 9. The reaction methodology
used here could be a potentially convenient route to more
examples of tethered indenyl Ru derivatives.
Figure 6. Hydrogen atoms-labelling of the indenyl 5-membered
ring of 9.
Experimental Section
0.066 Å), understandably an effect of the asymmetry of the
ethene moiety with higher steric constraint at bridgehead-like
C(9). In contrast, complex C shows only a small difference in
the Ru-C bonds of the metal center to the ethene moiety. While
the Ru(1)-O distances in 9 (range 2.0563(19)-2.1067(18) Å)
are similar to those in Bennett’s Ru(acac) complexes, the Ru-
(1)-O(2) bond is substantially longer (∆ ≈ 0.04-0.05 Å),
rationalized as a consequence of the trans effect of the P donor
atom.
General Procedures. All reactions were carried out using
conventional Schlenk techniques under an inert atmosphere of
nitrogen or under argon in an M. Braun Labmaster 130 inert gas
system.
NMR spectra were measured on a Bruker 300 FT NMR
spectrometer, while that of 9 and the 2D-COSY spectra of 4 and 9
were recorded on a Bruker 500 FT NMR spectrometer; for 1H and
31P spectra, chemical shifts were referenced to residual solvent in
the deuterosolvents C6D6 and (CD3)2CO. IR spectra in KBr pellets
were measured in the range 4000-400 cm-1, using a BioRad FTS-
165 FTIR instrument. Mass spectra were run on a Finnigan Mat
95XL-T (FAB) or a Finnigan-MAT LCQ (ESI) spectrometer.
Elemental analyses were performed by the microanalytical labora-
tory in-house.
The spectroscopic data of 9, obtained from a proton NMR
scan and a 2D-COSY experiment, are consistent with the
structure. Thus, the proton spectrum shows the four chemically
inequivalent Me groups of the two acac ligands at δ 1.34-
1.80 and the allylic protons at δ 4.29 and 4.96. The protons on
C10 and C11, the ethylene side arm, appear as four sets of
multiplets in the range δ 2.32-2.89. Referring to the atom-
labeling code shown in Figure 6, the “ene” proton (H1 on C1)
of the five-membered ring of Ind appears as a doublet at δ 5.15
[(C10H16)RuCl2]2 (1)17 and IndH(CH2)2PPh2 (LH)5b were pre-
pared by published methods. All other chemicals were obtained
commercially and used as supplied. All solvents were dried over
sodium/benzophenone and distilled before use. Celite (Fluka AG),
silica gel (Merck Kieselgel 60, 230-400 Mesh), and neutral alumina
(acitivity III) were dried at 140 °C overnight before chromatographic
use. Synthesis of [(η3,η3-C10H16)RuCl2(κ1P-LH)] (2). 1 (100 mg,
0.16 mmol) was added into an ether solution of LH (106 mg, 0.32
mmol, 10 mL), and the suspension was stirred for 4 h, whereupon
the color of the suspension changed slowly from purplish red to
yellow. Yellow solids of 2 were filtered (93 mg, 45% yield). The
filtrate was concentrated to ca. 1 mL, and hexane (ca. 5 mL) was
added. A second crop of yellow microcrystals of 2 were obtained
after 1 day at -30 °C (73 mg, 35% yield). Single crystals of X-ray
diffraction quality were obtained from a solution of 2 in CH2Cl2
layered with hexane after 2 days at -30 °C.
3
with JHH ) 3.7 Hz (coupling with H2), while the sp3-protons
H2 on C2 appears as a doublet of a doublet at δ 3.39 (3JHH
)
3.7 Hz and JHH ) 20 Hz) and H3 appears as a doublet at δ
3.61 (2JHH ) 20 Hz; coupling with H2). The correlation of each
signal was established using 2D-COSY NMR spectroscopy.
There was no coupling observed between H3 and H1. This
observation was further supported by the X-ray structure, which
shows that H1 and H3 are almost orthogonal (83.7°) and
therefore will have minimal transmission of nuclear spin
information, resulting in no coupling, according to Karplus
rule.25 The angle between H2 and H3 is 109.2°, with a geminal
coupling constant of 20 Hz, which is slightly larger than the
2JHH of a typical sp3 protons on a C6 ring with angle between
the protons of ∼109°.25
2
1
Data for 2. H NMR (CD3CN): δ 2.15 (s, 6 H, Me), 2.24-
2.38 (m, 2 H, IndH(CH2)2PPh2), 2.50-2.60 (m, 2 H, IndH(CH2)2-
PPh2), 2.63-2.68 (m, 2 H, Hd and Hf), 3.12-3.14 (d-like, 2 H, Hb
and Hj), 3.29 (s, 2 H, H2-3), 3.39-3.45 (m, 2 H, He and Hg), 4.24-
4.28 (d-like, 2 H, Ha and Hi), 5.12 (br s, 2 H, Hc and Hh), 6.26 (s,
1 H, H1), 7.10-7.21, 7.42-7.49, 7.72-7.78, and 7.86-7.92 (each
m, total 14 H, Ph and H4-7). 31P{1H} NMR (CD3CN): δ 18.9 (s,
IndH(CH2)2PPh2). FAB+-MS: m/z 636 [M]+, 601 [M - Cl]+, 565
[M - 2Cl]+, 464 [M - C10H16 - Cl]+, 429 [M - C10H16 - 2Cl]+.
Anal. Calc (Found) for C33H37Cl2PRu: C, 62.3 (62.1); H, 5.9 (6.0).
Synthesis of [((η3,η3-C10H16)RuCl(CH3CN)(κ1P-LH)](CF3SO3)
(2a‚CF3SO3). CF3SO3H (9 µL, 0.10 mmol) was slowly injected
into a stirred solution of 2 (30 mg, 0.047 mmol) in ether/CH3CN
(30:1, 10 mL), precooled to 0 °C. Yellow solids slowly precipitated
out of the solution. The suspension was filtered after 1 h to give
yellow solids of [2a]CF3SO3 (25 mg, 83% yield). Single crystals
of X-ray diffraction quality were obtained from a THF solution
with ether diffusion after 10 days at -30 °C.
The formation of the Ru(II) complex 9 had involved multiple
processes, viz., chloride abstraction from 2 by Na+ ions,
followed by coordination of two acac- ligands with displace-
ment of the bis(allyl) ligand. This so-formed 16-electron
“intermediate” would not be able to accept a η5-indenyl ligand,
unless one of the acac ligands can be displaced. That this had
not occurred is consistent with the relative bond strength of the
acac- versus η5-ind ligands. The metal center of the “intermedi-
ate” therefore achieves its 18-electron configuration by coor-
dinating to the “-ene” moiety of the LH ligand, giving rise to
a (η2,κ1P-) bonding mode at Ru(II).
Attempts to synthesize the (η5,κ1P-L)Ru(II) complex with
labile CH3CN ligands were in vain, as refluxing 2 in a solvent
mixture of EtOH/CH3CN (1:1), Na2CO3, and KPF6 led only to
an inseparable complex mixture, indicating the need of strong
donor ligands to stabilize (η5,κ1P-L)Ru(II) complexes.
Data for [2a]CF3SO3. 1H NMR (CD3CN): δ 1.67 and 2.27 (each
s, 3 H, Me), 2.13-2.26 and 2.35-2.49 (each m, 1 H, IndH(CH2)2-
PPh2), 2.84 and 3.19 (each unresolved d, 1 H, IndH(CH2)2PPh2),
2.74-2.80 (m, 2 H, Hd and Hf), 3.03-3.15 (m, 2 H, Hb and Hj),
3.28 (s, 2 H, H2-3), 3.51-3.73 (m, 2 H, He and Hg), 4.28 and 4.40
(each d, J ) 9.1 Hz, 1 H, Ha and Hi), 4.92-4.95 (d-liked, 1 H, Hc
or Hh), 5.32-5.36 (unresolved td, 1 H, Hc or Hh), 6.26 (s, 1 H,
H1), 6.89-6.92, 7.13-7.21, 7.42-7.44, 7.53-7.61, 7.75-7.81, and
7.98-8.04 (each m, total 14 H, Ph and H4-7). 31P{1H} NMR (CD3-
Conclusion
A synthetic route has been developed for the transformation
of bis(allyl)Ru(IV) precursor 2 to tethered [(η5,κ1P-L)Ru(II)]
(24) Alvarez, P.; Lastra, E.; Gimeno, J.; Bran˜a, P.; Sordo, J. A.; Gomez,
J.; Falvello, L. R.; Bassetti, M. Organometallics 2004, 23, 2956.
(25) Pavia, D. L., Lampman, G. M., Kriz, G. S., Eds. Introduction to
Spectroscopy; Saunders College Publishing, 1996; p 189.

Tethered Indenyl-Phosphine Complexes of Ruthenium(II)
Organometallics, Vol. 26, No. 14, 2007 3359
Chart 1. Hydrogen Atom Labeling of the Bis(allyl) and Coordinated LH Ligands
CN): δ 22.2 (s, IndH(CH2)2PPh2). IR (ν cm-1, KBr): 3061 w,
2976 w, 2925 w, 2865 w, 2293 w (CN), 1437 m (CF3SO3), 1387
w (CF3SO3), 1265 vs (CF3SO3), 1223 m, 1151 s (CF3SO3), 1032 s
(CF3SO3), 772 m, 753 m, 699 m, 638 s, 516 m. FAB+-MS: m/z
601 [M - CH3CN]+, 565 [M - CH3CN - Cl]+, 429 [M - CH3-
CN - Cl - C10H16]+. Anal. Calc (Found) for C36H40ClF3NO3-
PSRu: C, 54.6 (54.6); H, 5.1 (5.2); N, 1.8 (1.7).
Synthesis of [(η5,κ1P-L)Ru(COD)]PF6, [3]PF6. Method 1. COD
(6 µL, 0.063 mmol) was injected into a stirred suspension of 2 (30
mg, 0.047 mmol) and AgPF6 (24 mg, 0.095 mmol) in EtOH (10
mL). After 2 h at RT, the suspension was filtered through Celite,
giving a yellow filtrate. This was evacuated to dryness and the
residue was crystallized from THF/hexane, giving orange-yellow
microcrystals of [(η5,κ1P-L)Ru(COD)]PF6, [3]PF6 (27 mg, 84%
yield).
7.25-7.28, 7.37-7.42, 7.68-7.72, and 8.02-8.07 (each m, total
29 H, Ph and H3-6). 31P{1H} NMR (C6D6): δ 49.0 and 52.5 (each
d, J ) 26.7 Hz, PPh3, Ind(CH2)2PPh2). FAB+-MS: m/z 726 [M]+,
691 [M - Cl]+, 464 [M - PPh3]+, 427 [M - Cl - PPh3]+. Anal.
Calc (Found) for C41H35ClP2Ru: C, 67.8 (67.6); H, 4.9 (5.2)
Synthesis of [(η5,κ1P-L)Ru(PPh3)H] (5). A brown mixture of
4 (10 mg, 13.8 mmol) and NaOMe (freshly generated from Na (2
mg, 87 mmol) in MeOH (5 mL)) in MeOH/THF (1:1, 10 mL) was
refluxed for 2 h. The color of the mixture slowly changed from
brownish-yellow to bright yellow. The solvent was evacuated to
dryness and the residue extracted with hexane (2 × 4 mL). The
hexane extract was concentrated to ca. 1 mL. Yellow solids of 5
(5 mg, 53% yield) were collected after 1 day at -30 °C.
Data for 5. 1H NMR (C6D6): δ -13.9 (dd, 1 H, J ) 23.7, 40.3
Hz, Ru-H), 1.72-1.89 (m, 1 H, Ind(CH2)2PPh2), 2.31-2.40 and
2.46-2.53 (each m, 0.5 H, Ind(CH2)2PPh2), 3.07-3.18, 3.57-3.69
(each m, 1 H, Ind(CH2)2PPh2), 4.78 and 5.48 (each s, 1 H, H1 and
H2), 6.40-6.43, 6.68-6.73, 6.76-6.84, 6.86-6.94, 7.01-7.08,
7.11-7.14, 7.51-7.54, and 7.91-7.97 (each m, total 29 H, Ph and
H3-6), and δ 0.39 (s, H2O). 31P{1H} NMR (C6D6): δ 66.1 and 78.8
(each d, J ) 23.7 Hz, PPh3, Ind(CH2)2PPh2). FAB+-MS: m/z 691
[M - H]+, 429 [M - PPh3]+. Anal. Calc (Found) for C41H36P2-
Ru‚1.5H2O: C, 68.5 (68.8), H, 5.5 (5.7).
Method 2. A yellow suspension of 2 (10 mg, 0.016 mmol), Na2-
CO3 (2 mg, 0.019 mmol), KPF6 (3 mg, 0.016 mmol), and COD (2
µL, 0.021 mmol) in EtOH (5 mL) was refluxed for 4 h. The yellow
solids of 2 slowly dissolved upon heating. The solution was
evacuated to dryness and extracted using THF. The extract was
concentrated to ca. 1 mL, and hexane (ca. 3 mL) was added.
Orange-yellow microcrystals of [3]PF6 were obtained after 1 day
at -30 °C (8 mg, 75% yield). Single crystals of X-ray diffraction
quality were obtained from a CH2Cl2 solution layered with hexane
after 3 days at -30 °C.
Synthesis of [(η5,κ1P-L)Ru(2,2′-bipyridyl)]PF6, [6]PF6, and
1
[(κ P-LH)Ru(2,2′-bipyridyl)Cl]PF6, [7]PF6. A yellow suspension
1
of 2 (30 mg, 0.047 mmol), 2,2′-bipyridyl (8 mg, 0.051 mmol), Na2-
CO3 (5 mg, 0.047 mmol), and KPF6 (9 mg, 0.049 mmol) in EtOH
(10 mL) was refluxed. A red mixture resulted after 4 h. The solvent
was removed under vacuum and the residue extracted using THF
(2 × 5 mL). The extract was concentrated to ca. 2 mL and loaded
onto a neutral alumina (activity III) column prepared in THF.
Elution gave four fractions: (i) a yellow eluate in THF (2 mL);
(ii) a red eluate in THF/acetone (4:1, ca. 25 mL), which gave [6]-
PF6 as a red oil (20 mg, 58% yield); (iii) a red eluate in THF/
acetone (1:1, ca. 8 mL), which gave [7]PF6 (11 mg, 25% yield) as
red solids upon recrystallization from CH2Cl2/ether (1:10); (iv) a
red eluate in MeOH (ca. 1 mL), which gave a trace of an unknown
species.
A similar reaction was repeated, using Li2CO3 (3.5 mg, 0.047
mmol) instead of Na2CO3. The 31P NMR spectrum of the reaction
mixture showed the presence of the cationic species [6]PF6, [7]-
PF6, and [8]PF6, in the ratio of 1:2:2. Separation of these complexes
via silica gel chromatography was futile, as complexes [7]PF6 and
[8]PF6 have similar polarity.
Data for [3]PF6. H NMR ((CD3)2CO): δ 0.66-0.77 (m, 1 H,
COD), 1.28-1.45 (m, 2 H, COD), 1.83-1.98 (m, 2 H, COD),
2.13-2.20 (m, 2 H, COD), 2.32-2.54 (m, 2 H, Ind(CH2)2PPh2),
2.60-2.89 (m, 2 H, Ind(CH2)2PPh2), 3.52-3.62 (m, 1 H, COD),
3.74-4.04 (m, 4 H, COD), 5.01 (d, 3JHH ) 2.5 Hz, 1 H, H2), 5.12
(br m, 1 H, H1), 6.70 (t, 1 H, H3-6), 7.00-7.03, 7.19-7.24, 7.42-
7.48, 7.56-7.71, and 7.75-7.86 (each m, total 13 H, Ph and H3-6).
31P{1H} NMR ((CD3)2CO): δ 67.7 (s, Ind(CH2)2PPh2), -142.6
(septet, PF6). IR (ν cm-1, KBr): 2922 w, 2850w, 1438 w, 1169 w,
1096 w, 836 vs (PF6), 751 m, 704 m, 557 m (PF6). FAB+-MS:
m/z 537 [M]+, 429 [M - COD]+. Anal. Calc (Found) for
C31H32F6P2Ru: C, 54.6 (54.7), H, 4.7 (4.8).
Synthesis of [(η5,κ1P-L)Ru(PPh3)Cl] (4). Method 1. A yellow
suspension of 2 (30 mg, 0.047 mmol), Na2CO3 (5 mg, 0.047 mmol),
and PPh3 (13 mg, 0.049 mmol) in EtOH (10 mL) was refluxed.
The mixture changed to a dark brown homogeneous solution. After
heating for 4 h, the solvent was removed under vacuum, and the
residue was extracted with toluene (2 × 2 mL). The extract was
concentrated to ca. 2 mL and then loaded onto a silica gel column
(2 × 5 cm) prepared in n-hexane. Elution gave two fractions: (i)
a yellow eluate in toluene (6-8 mL), which yielded [(η5,κ1P-L)-
Ru(PPh3)H], 5 (5 mg, 15% yield; see synthesis below); (ii) a dark
brown eluate in toluene/ether (1:1, 12-15 mL), which yielded dark
brown crystals of 4 (20 mg, 58% yield) suitable for X-ray diffraction
analysis, upon recrystallization from ether.
HCl (0.35 mL of 0.1 M) was added into a red solution of [6]PF6
(5 mg, 0.007 mmol), and 2,2′-bipyridyl (1.6 mg, 0.01 mmol) in
EtOH (0.5 mL) was reluxed for 2 h. The solvent was evacuated to
dryness and the residue redissolved in d-acetone. 1H and 31P NMR
spectroscopy showed the total conversion to [7]PF6 and [8]PF6 in
2:1 ratio.
Method 2. A procedure similar to method 1 was adopted using
0.5 equiv of Na2CO3 (2.5 mg, 0.023 mmol). Dark brown crystals
of 4 were obtained in 82% yield (28 mg), while 5 was not formed.
Data for 4. 1H NMR (C6D6): δ 1.42-1.52 and 1.52-1.64 (each
m, 0.5 H, Ind(CH2)2PPh2), 1.89-2.06 (m, 1 H, Ind(CH2)2PPh2),
2.26 (s, 1 H, H1), 2.78-2.91 and 3.10-3.22 (each m, 1 H, Ind-
(CH2)2PPh2), 4.87 (s, 1 H, H2), 6.64-6.69, 6.79-6.83, 6.93-7.12,
A red suspension of [8]PF6 (4 mg, 0.003 mmol), 2,2′-bipyridyl
(0.4 mg, 0.003 mmol), and KPF6 (0.5 mg, 0.003 mmol) in EtOH
(0.5 mL) was refluxed for 2 h. The resultant red solution was
evacuated to dryness and redissolved in d-acetone. 1H and 31P NMR
spectroscopy showed the total conversion of species 8 to 7.
1
Data for [6]PF6. H NMR ((CD3)2CO): δ 2.82-3.24 (m, 2 H,
Ind(CH2)2PPh2), 3.74-3.94 (m, 2 H, (Ind(CH2)2PPh2), 5.21 (d, 3JHH

3360 Organometallics, Vol. 26, No. 14, 2007
Table 2. Crystal and Structure Refinement Data
Ng et al.
2
[2a]CF3SO3
3
4
9
formula
C
33.50H38.25Cl2O0.13PRu
C36H40ClF3NO3PRuS
791.24
P21/n
C32H34Cl2F6P2Ru
766.50
P1h
C42H37.50ClO0.25P2Ru
744.68
P1h
C33H35O4PRu
627.65
P21/c
molecular weight
space group
(cryst syst)
cryst syst
unit cell dimens
a (Å)
645.83
P1h
triclinic
monoclinic
triclinic
triclinic
monoclinic
12.1186(4)
12.4772(5)
20.6703(8)
90.5620(10)
101.7530(10)
96.6540(10)
3037.5
14.6702(8)
9.0353(5)
26.8742(15)
90
99.9560(10)
90
3508.5(3)
4
1.498
9.1518(5)
13.3458(8)
13.6837(8)
69.821(2)
75.8110(10)
81.523(2)
1517.23(15)
2
11.1768(12)
16.1725(17)
21.521(2)
84.424(3)
81.268(3)
70.180(3)
3612.8(7)
4
29.3586(12)
11.4964(4)
17.9306(7)
90
106.0200(10)
90
5816.9(4)
8
1.433
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
cell volume (Å 3)
Z
4
D
calc (g cm-3
)
1.412
1.678
1.369
absorp coeff (mm-1
F(000) electrons
cryst size (mm3)
θ range for data
collection (deg)
index ranges
)
0.766
1333
0.681
1624
0.859
776
0.626
1530
0.630
2592
0.28 × 0.16 × 0.14
0.60 × 0.20 × 0.14
0.14 × 0.10 × 0.04
0.10 × 0.06 × 0.02
0.30 × 0.20 × 0.16
2.01 to 29.09
1.48 to 25.00
1.62 to 25.00
0.96 to 25.00
0.72 to 27.50
-16 e h e 15
-16 e k e 16
0 e l e 28
40 877
14 685
0.9003-0.8140
-17 e h e 16
-9 e k e 10
-31 e l e 31
19 971
6200
0.9107-0.6855
-10 e h e 10
-15 e k e 10
-16 e l e 13
9007
5337
0.9665-0.8892
-13 e h e 13
-19 e k e 19
-25 e l e 25
38 904
12 708
0.9876-0.9401
-28 e h e 38
-14 e k e 14
-23 e l e 18
40 443
13 340
0.9059-0.8335
no. of reflns collected
no. of indep reflns
max. and min.
transmn
no. of data/restraints/
params
14 685/0/692
6200/42/420
5337/0/388
12 708/58/855
13 340/0/719
GoF
1.101
1.024
1.144
1.185
1.064
final R indices
[I > 2σ(I)]
R1 ) 0.0608
R1 ) 0.0672
R1 ) 0.0713
R1 ) 0.1359
R1 ) 0.0425
wR2 ) 0.1346
R1 ) 0.0834
wR2 ) 0.1447
1.122 and -0.801
wR2 ) 0.1708
R1 ) 0.1033
wR2 ) 0.1904
1.071 and -0.524
wR2 ) 0.1453
R1 ) 0.0898
wR2 ) 0.1537
1.174 and -0.963
wR2 ) 0.3149
R1 ) 0.1596
wR2 ) 0.3259
2.991 and -1.541
wR2 ) 0.0938
R1 ) 0.0547
wR2 ) 0.1021
0.919 and -0.356
R indices (all data)
largest diff peak and
hole (e Å -3
)
) 2.5 Hz, 1 H, H2), 5.53 (m, 1 H, H1), 6.82-6.94, 7.07-7.38,
7.44-7.49, 7.54-7.70, 7.80-7.91, 8.35-8.40, and 9.04-9.06 (each
m, total 22 H, bipyridyl, Ph and H3-6), and δ 1.80 and 3.62 (each
m, THF). 31P{1H} NMR ((CD3)2CO): δ 61.7 (s, Ind(CH2)2PPh2),
-142.6 (septet, PF6). IR (ν cm-1, KBr): 3054 w, 2923 w, 1436 w,
1265 w, 1161 w, 1096 w, 1029 w, 841 vs (PF6), 745 w, 699 w,
558 w (PF6), 518 w. FAB+-MS: m/z 585 [M]+, 429 [M -
bipyridyl]+. Anal. Calc (Found) for C33H29F6N2P2Ru‚C4H8O: C,
55.3 (55.3); H, 4.6 (4.1); N, 3.5 (3.4).
(each td-like m, 1 H, bipyridyl), 7.13-7.35 and 7.38-7.44 (each
m, total 14 H, Ph and H4-7), 8.18-8.24 (t-like m, 2 H, bipyridyl),
3
9.08 and 9.18 (each d, JHH ) 4.9 Hz, 1 H, bipyridyl). 31P{1H}
NMR ((CD3)2CO): δ 54.5 (s, IndH(CH2)2PPh2), -142.6 (septet,
PF6). FAB+-MS: m/z 1279 [M]+, 777 [M - Ru(LH)Cl2]+, 585
[M - Ru(LH)(N2C10H8)Cl2]+, 465 [M - (LH)2(N2C10H8)]+, 429
[M - (LH)2(N2C10H8)Cl]+. HR-FAB+-MS for C66H56N4Cl3P2Ru2
[M]+: m/z 1278.1131 (found), 1278.1121 (calc). Anal. Calc (Found)
for C66H56Cl3F6N4P3Ru2: C, 55.8 (55.4); H, 4.0 (3.9); N, 3.9 (4.0).
Synthesis of [(η2,κ1P-L)Ru(acac)2] (9). A yellow suspension
of 2 (30 mg, 0.047 mmol), Na2CO3 (13 mg, 0.12 mmol), and acetyl
acetone (12 µL, 0.12 mmol) in EtOH (10 mL) was refluxed. As
the reaction proceeded, a yellow mixture resulted. After refluxing
for 4 h, the solvent was removed under vacuum and the residue
extracted using hexane (2 × 5 mL). The extract was concentrated
to ca. 2 mL and loaded onto a silica gel column (1 × 8 cm) prepared
in n-hexane. Elution gave two fractions: (i) a yellow eluate in
hexane/ether (6:1, 2 mL), which yielded <1 mg of a solid material,
probably also of 9; (ii) a yellow eluate in hexane/ether (4:1, 8 mL),
which upon recrystallization from hexane yielded yellow crystals
of 9 (23 mg, 78% yield). X-ray diffraction-quality crystals were
obtained from a concentrated hexane solution in an NMR tube after
1 h at room temperature.
1
Data for [7]PF6. H NMR ((CD3)2CO): δ 2.25-2.38 (m, 2 H,
IndH(CH2)2PPh2), 2.84-2.91 (m, 2 H, IndH(CH2)2PPh2), 3.23-
3.24 (m, 2 H, H2-3), 6.10 (s, 1 H, H1), 6.91-6.94, 6.96-7.01, 7.03-
7.16, 7.24-7.28, 7.38-7.47, 7.52-7.57, 7.63-7.68, 7.78-7.83,
8.00-8.18, 8.23-8.29, 8.48-8.50, 8.64-8.70, 9.17-9.19, and
9.84-9.86 (each m, total 30 H, bipyridyl, Ph and H4-7). 31P{1H}
NMR ((CD3)2CO): δ 39.5 (s, IndH(CH2)2PPh2), -142.6 (septet,
PF6). IR (ν cm-1, KBr): 3069 w, 2921 w, 1459 w, 1439 w, 1162
w, 1096 w, 1025 w, 842 vs (PF6), 763 m, 558 w (PF6), 521 w.
FAB+-MS: m/z 777 [M]+, 449 [M - (LH)]+. Anal. Calc (Found)
for C43H36ClF6N2P2Ru‚1/2CH2Cl2: C, 54.1 (54.2); H, 3.9 (4.2); N,
5.8 (6.2).
Synthesis of { [(κ1P-LH)Ru(2,2′-bipyridyl)]2(µ-Cl3)}PF6, [8]-
PF6. HCl (0.7 mL of 0.1 M) was added into a red solution of [6]-
PF6 (10 mg, 0.014 mmol) in EtOH, and the solution was stirred at
RT for 4 h. The resultant red solution was evacuated to dryness.
The residue was dissolved in acetone and the solution passed
through a short neutral alumina (activity III) column. Subsequent
workup of the red eluate in acetone/ether (3:1) gave [8]PF6 as
crystalline red flakes (7 mg, 70% yield).
Data for [8]PF6. 1H NMR ((CD3)2CO): δ 2.48 (br s, 2 H, IndH-
(CH2)2PPh2), 2.70-2.80 (m, 2 H, IndH(CH2)2PPh2), 3.23 (s, 2 H,
H2-3), 6.10 (s, 1 H, H1), 6.94-6.96, 6.99-7.04, and 7.76-7.81
Data for 9. 1H NMR (CD2Cl2): δ 1.34 (s, 3 H, Me), 1.43 (s, 3
H, Me), 1.68 (s, 3 H, Me), 1.80 (s, 3 H, Me), 2.32 - 2.45 (m, 1 H,
Ind(CH2)2PPh2), 2.50-2.73 (m, 2 H, Ind(CH2)2PPh2), 2.71-2.74
and 2.81-2.89 (each m, 0.5 H, Ind(CH2)2PPh2), 3.39 (dd, J ) 3.7,
20 Hz, 1 H, H2), 3.61 (d, J ) 20 Hz, 1 H, H3), 4.29 and 4.96 (each
s, 1 H, [(CH3)C(O)]2CH), 5.15 (d, J ) 3.7 Hz, H1), 6.91-6.97,
6.98-7.07, 7.09-7.22, 7.24-7.30, 7.34-7.45, and 7.96-8.03 (each
m, total 14 H, H4-7), and δ 0.89 and 1.23 (each m, hexane). 31P-
{1H} NMR (CD2Cl2): δ 70.4 (s, Ind(CH2)2PPh2). IR (ν cm-1
,

Tethered Indenyl-Phosphine Complexes of Ruthenium(II)
Organometallics, Vol. 26, No. 14, 2007 3361
KBr): 3054 w, 2915 w, 2872 w, 2835 w, 1581 s (CO), 1513 vs
(CO), 1435 m, 1395 s, 1261 w, 1196 w, 1097 w, 1019 w, 938 w,
855 w, 741 w, 698 m, 603 w, 528 m. FAB+-MS: m/z 628 [M]+,
528 [M - acac]+, 429 [M - 2 acac]+. Anal. Calc (Found) for
C33H35O4PRu‚1/4C6H12: C, 63.8 (63.8); H, 5.9 (5.6).
Crystal Structure Determinations. Crystals were mounted on
quartz fibers. X-ray data were collected on a Bruker AXS APEX
system, using Mo KR radiation, with the SMART suite of
programs.26 Data were processed and corrected for Lorentz and
polarization effects with SAINT27 and for absorption effects with
SADABS.28 Structural solution and refinement were carried out
with the SHELXTL suite of programs.29 Crystal and structure
refinement data are summarized in Table 2. The structures were
solved by direct methods or Patterson maps to locate the heavy
atoms, followed by difference maps for the light, non-hydrogen
atoms. All non-hydrogen atoms were generally given anisotropic
displacement parameters in the final model.
The crystal of 2 contained a diethyl ether solvent molecule with
partial occupancy. This was modeled as disordered over an inversion
center.
Acknowledgment. The authors acknowledge with thanks
support from the Academic Research Fund (grant no. 143-000-
209-112 to L.Y.G.) and Institute of Chemical and Engineering
Sciences for a research scholarship to S.Y.N.
Supporting Information Available: Complete crystallographic
data in CIF format for 2, 2a, 3, 4, and 9 and 1H NMR (500 MHz)
spectrum of 9 showing signals of H1-3. This material is available
free of charge via the Internet at http://pubs.acs.org.
(26) SMART version 5.628; Bruker AXS Inc.: Madison, WI, 2001.
(27) SAINT+ version 6.22a; Bruker AXS Inc.: Madison, WI, 2001.
(28) Sheldrick, G. M. SADABS, 1996.
(29) SHELXTL version 5.1; Bruker AXS Inc.: Madison, WI, 1997.
OM070225J