Synthesis and reactivity of ruthenium arene complexes incorporating novel Ph2PCH2CH2BR2 ligands. Easy access to the four-membered ruthenacycle [(p-cymene)RuCl(κC,P-CH 2CH2PPh2)]

Article abstract of DOI:10.1021/om701139a

The ambiphilic ligands Ph₂PCH₂CH₂BR ₂ (1a,b: BR₂ = BCy₂ (a), 9-BBN (b)) were readily prepared by hydroboration of vinyldiphenylphosphine. Reaction of 1a,b with [(p-cymene)RuCl₂]₂ afforded the corresponding complexes [(p-cymene)RuCl₂(Ph₂PCH₂CH ₂BR₂)] (2a,b), in which the borane moiety remains pendant, as confirmed by an X-ray diffraction analysis of 2b. Reaction of 2a,b with AgBF₄ in the presence of acetonitrile leads to the formation of the corresponding cationic complexes [(p-cymene)RuCl-(Ph₂PCH ₂CH₂BR₂)(CH₂CN)][BF₄] (3a,b) without alteration of the pendant borane moiety. In contrast, treatment of 2a,b with AgOAc induces CH₂-B bond cleavage and affords the four-membered ruthenacycle [(p-cymene)RuCl(κ^C,P-CH ₂CH₂PPh₂)] (4), characterized by X-ray diffraction. By reaction with chlorodicyclohexylborane, 4 gives back 2a via ring-opening σ-bond metathesis, whereas 4 reacts with chlorodiethylalane via alkylation at ruthenium with retention of the four-membered metallacycle to afford the ethyl complex [(p-cymene)RuEt(κ^C,P-CH ₂CH₂PPh₂)] (5).

Full text of DOI:10.1021/om701139a

1140
Organometallics 2008, 27, 1140–1146
Synthesis and Reactivity of Ruthenium Arene Complexes
Incorporating Novel Ph2PCH2CH2BR2 Ligands. Easy Access to the
Four-Membered Ruthenacycle [(p-cymene)RuCl(KC,P-CH2CH2PPh2)]
Jérôme Vergnaud,†,‡ Mary Grellier,† Ghenwa Bouhadir,‡ Laure Vendier,†
Sylviane Sabo-Etienne,*,† and Didier Bourissou*,‡
Laboratoire de Chimie de Coordination du CNRS, 205 route de Narbonne, 31077 Toulouse Cedex 04,
France, and Laboratoire Hétérochimie Fondamentale et Appliquée (UMR-CNRS 5069), UniVersité Paul
Sabatier, 118 route de Narbonne, F-31062 Toulouse Cedex 09, France
ReceiVed NoVember 13, 2007
The ambiphilic ligands Ph2PCH2CH2BR2 (1a,b: BR2 ) BCy2 (a), 9-BBN (b)) were readily prepared
by hydroboration of vinyldiphenylphosphine. Reaction of 1a,b with [(p-cymene)RuCl2]2 afforded the
corresponding complexes [(p-cymene)RuCl2(Ph2PCH2CH2BR2)] (2a,b), in which the borane moiety remains
pendant, as confirmed by an X-ray diffraction analysis of 2b. Reaction of 2a,b with AgBF4 in the presence
of acetonitrile leads to the formation of the corresponding cationic complexes [(p-cymene)RuCl-
(Ph2PCH2CH2BR2)(CH3CN)][BF4] (3a,b) without alteration of the pendant borane moiety. In contrast,
treatment of 2a,b with AgOAc induces CH2-B bond cleavage and affords the four-membered ruthenacycle
[(p-cymene)RuCl(κC,P-CH2CH2PPh2)] (4), characterized by X-ray diffraction. By reaction with chlorodi-
cyclohexylborane, 4 gives back 2a via ring-opening σ-bond metathesis, whereas 4 reacts with
chlorodiethylalane via alkylation at ruthenium with retention of the four-membered metallacycle to afford
the ethyl complex [(p-cymene)RuEt(κC,P-CH2CH2PPh2)] (5).
Chart 1
Introduction
Ambiphilic ligands combining donor and acceptor moieties
(referred to as D and A, respectively) have attracted increasing
attention over the past few years. The Lewis base moiety D is
expected to coordinate to a metal center as a classical L ligand,
while the Lewis acid fragment A can remain pendant1 or,
alternatively, interact with either a coligand2 or the metal
itself.2e,3 The three coordination modes I-III can thus be
distinguished (Chart 1). All of them have been evidenced
spectroscopically and structurally. In particular, the DfMfA
bridging coordination (mode III) has been exploited to gain
more insight into unusual Mfborane interactions,4,5 which were
first authenticated structurally in metallaboratranes.6 In addition,
the presence of pendant Lewis acid moieties (mode I) opens
interesting perspectives in organometallic catalysis, via anchor-
ing a substrate in the coordination sphere1a,c,7or activating
intramolecularly a M-X bond.8These developments have
stimulated our efforts to increase the structural variety of
ambiphilic derivatives and to study the reactivity of complexes
incorporating such structures.
Phosphine-borane (PB) derivatives have already proved very
fruitful in coordination chemistry2e–g,3 and also as metal-free
systems for the reversible activation of H2,9 as readily tunable
fluorescent systems,10 and as direct precursors for photoisomer-
izable heterodienes.11 We thus decided to retain the PB
combination but to modify the linker that dictates the distance
between both sites and the flexibility of the whole ligand. So
* To whom correspondence should be addressed. E-mail: sabo@lcc-
toulouse.fr (S.S.-E.); dbouriss@chimie.ups-tlse.fr (D.B.)
† Laboratoire de Chimie de Coordination du CNRS.
‡ Université Paul Sabatier.
(1) A few cyclopentadienyl and arene complexes featuring pendant
boranes have been reported: (a) Spence, R. E. v. H.; Piers, W. E.
Organometallics 1995, 14, 4617–4624. (b) Green, M. L. H.; Wagner, M.
J. Chem. Soc., Dalton Trans. 1996, 2467–2473. (c) Piers, W. E.; Sun, Y.;
Lee, W. M. T. Top. Catal. 1999, 7, 133–143. (d) Hill, M.; Kehr, G.; Fröhlich,
R.; Erker, G. Eur. J. Inorg. Chem. 2003, 3583–3589. (e) Hill, M.; Kehr,
G.; Erker, G.; Kataeva, O.; Fröhlich, R. Chem. Commun. 2004, 1020–1021.
(f) Hill, M.; Erker, G.; Kehr, G.; Fröhlich, R.; Kataeva, O. J. Am. Chem.
Soc. 2004, 126, 11046–11057. (g) Erker, G.; Aul, R. Chem. Ber. 2006,
124, 1301–1310. (h) Kestel-Jakob, A.; Alt, H. G. Z. Naturforsch. 2007,
62b, 314–322.
(2) (a) Baker, R. T.; Calabrese, J. C.; Westcott, S. A.; Marder, T. B.
J. Am. Chem. Soc. 1995, 117, 8777–8784. (b) Lancaster, S. J.; Al-Benna,
S.; Thornton-Pett, M.; Bochmann, M. Organometallics 2000, 19, 1599–
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(d) Arndt, P.; Jäger-Fiedler, U.; Klahn, M.; Baumann, W.; Spannenberg,
A.; Burlakov, V. V.; Rosenthal, U. Angew. Chem., Int. Ed. 2006, 45, 4195–
4198. (e) Bontemps, S.; Bouhadir, G.; Miqueu, K.; Bourissou, D. J. Am.
Chem. Soc. 2006, 128, 12056–12057. (f) Emslie, D. J. H.; Blackwell, J. M.;
Britten, J. F.; Harrington, L. E. Organometallics 2006, 25, 2412–2414. (g)
Oakley, S. R.; Parker, K. D.; Emslie, D. J. H.; Vargas-Baca, I.; Robertson,
C. M.; Harrington, L. E.; Britten, J. F. Organometallics 2006, 25, 5835–
5838. (h) Vergnaud, J.; Ayed, T.; Hussein, K.; Vendier, L.; Grellier, M.;
Bouhadir, G.; Barthelat, J.-C.; Sabo-Etienne, S.; Bourissou, D. Dalton Trans.
2007, 2370–2372.
(3) (a) Bontemps, S.; Gornitzka, H.; Bouhadir, G.; Miqueu, K.;
Bourissou, D. Angew. Chem., Int. Ed. 2006, 45, 1611–1614. (b) Bontemps,
S.; Sircoglou, M.; Bouhadir, G.; Puschmann, H.; Howard, J. A. K.; Dyer,
P. W.; Miqueu, K.; Bourissou, D. Chem. Eur. J. 2007, 14, 731. (c) Sircoglou,
M.; Bontemps, S.; Mercy, M.; Saffon, N.; Takahashi, M.; Bouhadir, G.;
Maron, L.; Bourissou, D. Angew. Chem., Int. Ed. 2007, 46, 8583–8586.
(d) Bontemps, S.; Sircoglou, M.; Bouhadir, G.; Puschmann, H.; Howard,
J. A. K.; Dyer, P. W.; Miqueu, K.; Bourissou, D. Chem. Eur. J. 2008, 14,
731–740. (e) Bontemps, S.; Bouhadir, G.; Gu, W.; Mercy, M.; Chen, C.-
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Int. Ed. 2008, 47, 1481–1484.
10.1021/om701139a CCC: $40.75
2008 American Chemical Society
Publication on Web 02/29/2008

Ru Arene Complexes with Ph2PCH2CH2BR2 Ligands
Organometallics, Vol. 27, No. 6, 2008 1141
far,12 essentially rigid aryl spacers such as o- and p-C6H4 groups
have been studied. 2e,3,9,13–15 In comparison, alkyl spacers have
only been scarcely studied,16 and we thus became interested in
incorporating a -CH2CH2- unit as a flexible version of the
o-C6H4 linker.
Scheme 1. Synthesis of the Phosphine-Borane ligands 1a,b
From a synthetic viewpoint, most of the PB and PAl systems
known to date have been prepared by ionic couplings from
phosphorus-containing nucleophiles and halogenoboranes or
-alanes.17,18 We thought that the hydroboration of vinylphos-
phines19,20 would provide a straightforward access to the desired
ligands from readily available precursors. To the best of our
knowledge, Et2PCH2CH2B(OCH2CH2O), prepared by hydro-
phosphination of the corresponding vinylboronate,21 was the
unique precedent of a phosphine-borane featuring a -CH2-
CH2- linker.22 Schmidbaur et al.23 recently studied the hy-
droboration of alkenylphosphines with 9-BBN.24 Accordingly,
allyl- and homoallylphosphines readily afforded P(CH2)nB (n
) 3, 4) derivatives stabilized by intramolecular PfB interac-
tions.23 The authors mentioned that such a reaction could not
be extrapolated to the vinyldiphenylphosphine.
We decided to revisit this entry route to PB ligands and report
here the synthesis of the phosphine-boranes Ph2PCH2CH2BR2
(BR2 ) BCy2, 9-BBN) via hydroboration and their coordination
to the (p-cymene)RuCl2 fragment. Neutral and cationic
ruthenium complexes can thus be obtained with the new
ligands adopting the coordination mode I (see Chart 1). The
synthesis, characterization, and reactivity of the four-
membered metallacycle [(p-cymene)RuCl(κC,P-CH2CH2PPh2)]
(4) are also described, highlighting the reversible breaking/
formation of the CH2B bond of the coordinated Ph2P-
CH2CH2BR2 ligands.
(4) Early claims for transition-metal-borane complexes were not
supported by structural authentication: (a) Shriver, D. F. J. Am. Chem. Soc.
1963, 85, 3509–3510. (b) Parshall, G. W. J. Am. Chem. Soc. 1964, 86,
361–364. (c) Johnson, M. P.; Shriver, D. F. J. Am. Chem. Soc. 1966, 88,
301–304. And their real identity has been strongly questioned: (d)
Braunschweig, H.; Wagner, T. Chem. Ber. 1994, 127, 1613–1614. (e)
Braunschweig, H.; Wagner, T. Z. Naturforsch., B 1996, 51, 1618–1620. (f)
Braunschweig, H.; Kollann, C. Z. Naturforsch., B 1999, 54, 839–842.
Metalfboron interactions have also been proposed to account for the bent
structure of metallocenylboranes: see: (g) Scheibitz, M.; Bolte, M.; Bats,
J. W.; Lerner, H.-W.; Nowik, I.; Herber, R. H.; Krapp, A.; Lein, M.;
Holthausen, M. C.; Wagner, M. Chem. Eur. J. 2005, 11, 584–603. (h)
Braunschweig, H.; Kraft, M.; Schwarz, S.; Seeler, F.; Stellwag, S. Inorg.
Chem. 2006, 45, 5275–5277. (i) Gleiter, R.; Bleiholder, C.; Rominger, F.
Organometallics 2007, 26, 4850–4859.
(5) For recent discussions on the precise nature of such interactions,
see: (a) Hill, A. F. Organometallics 2006, 25, 4741–4743. (b) Parkin, G.
Organometallics 2006, 25, 4744–4747, and ref 3c.
(6) (a) Hill, A. F.; Owen, G. R.; White, A. J. P.; Williams, D. J. Angew.
Chem., Int. Ed. 1999, 38, 2759–2761. (b) Crossley, I. R.; Hill, A. F.
Organometallics 2004, 23, 5656–5658. (c) Mihalcik, D. J.; White, J. L.;
Tanski, J. M.; Zakharov, L. N.; Yap, G. P. A.; Incarvito, C. D.; Rheingold,
A. L.; Rabinovitch, D. Dalton Trans. 2004, 1626–1634. (d) Crossley, I. R.;
Hill, A. F.; Willis, A. C. Organometallics 2005, 24, 1062–1064. (e) Crossley,
I. R.; Foreman, M. R. St.-J.; Hill, A. F.; White, A. J. P.; Williams, D. J.
Chem. Commun. 2005, 221–223. (f) Crossley, I. R.; Hill, A. F.; Humphrey,
E. R.; Willis, A. C. Organometallics 2005, 24, 4083–4086. (g) Crossley,
I. R.; Hill, A. F.; Willis, A. C. Organometallics 2006, 25, 289–299. (h)
Landry, V. K.; Melnick, J. G.; Buccella, D.; Pang, K.; Ulichny, J. C.; Parkin,
G. Inorg. Chem. 2006, 45, 2588–2597. (i) Blagg, R. J.; Charmant, J. P. H.;
Connelly, N. G.; Haddow, M. F.; Orpen, A. G. Chem. Commun. 2006, 2350–
2352. (j) Figueroa, J. S.; Melnick, J. G.; Parkin, G. Inorg. Chem. 2006, 45,
7056–7058. (k) Pang, K.; Quan, S. M.; Parkin, G. Chem. Commun. 2006,
5015–5017. (l) Senda, S.; Ohki, Y.; Hirayama, T.; Toda, D.; Chen, J.-L.;
Matsumoto, T.; Kawaguchi, H.; Tatsumi, K. Inorg. Chem. 2006, 45, 9914–
9925. (m) Crossley, I. R.; Hill, A. F.; Willis, A. C. Organometallics 2007,
26, 3891–3895. (n) Crossley, I. R.; Hill, A. F. Dalton Trans. 2008, 201–
203.
Results and Discussion
Synthesis of the Ligands Ph2PCH2CH2BR2 (1a,b: BR2
) BCy2 (a), 9BBN (b)). The hydroboration of vinyldiphe-
nylphosphine was first investigated with Cy2BH. The reaction
readily occurs at room temperature in THF and is complete
within 1 h. The desired product 1a was obtained in nearly
quantitative yield as a white solid (Scheme 1). The monomeric
structure of 1a and the absence of an intramolecular PfB
interaction were indicated by multinuclear NMR spectroscopy.
(7) (a) Börner, A.; Ward, J.; Kortus, K.; Kagan, H. B. Tetrahedron:
Asymmetry 1993, 4, 2219–2228. (b) Fields, L. B.; Jacobsen, E. N.
Tetrahedron: Asymmetry 1993, 4, 2229–2240.
(8) (a) Fontaine, F.-G.; Zargarian, D. J. Am. Chem. Soc. 2004, 126, 8786–
8794. (b) Thibault, M.-H.; Mathiotte, S.; Frouin, F.; Sigouin, O.; Michaud,
A.; Fontaine, F.-G. Organometallics 2007, 26, 3807–3815.
(9) (a) Welch, G. C.; San Juan, R. R.; Masuda, J. D.; Stephan, D. W.
Science 2006, 314, 1124–1126. (b) Kubas, G. J. Science 2006, 314, 1096–
1097. (c) Chase, P. A.; Welch, G. C.; Jurca, T.; Stephan, D. W. Angew.
Chem., Int. Ed. 2007, 46, 8050–8053. (d) Spies, P.; Erker, G.; Kehr, G.;
Bergander, K.; Fröhlich, R.; Grimme, S.; Stephan, D. W. Chem. Commun.
2007, 5072–5074.
(17) The synthesis of p-Mes2P-(C6F4)-B(C6F5)2 is a noticeable excep-
tion and starts by an aromatic nucleophilic substitution from Mes2PH and
B(C6F5)3.9a
(18) R2BC(R)dC(R′)PR′′2 were prepared from the alkynylborates
Na[R3BCCR′] and R′′2PCl: (a) Binger, P.; Köster, R. J. Organomet. Chem.
1974, 73, 205–210. (b) Balueva, A. S.; Erastov, O. A. IzV. Akad. Nauk
SSSR, Ser. Khim. 1988, 1, 163–165. (c) Balueva, A. S.; Nikonov, G. N.;
Vul’fson, S. G.; Sarvarova, N. N.; Arbuzov, B. A. IzV. Akad. Nauk SSSR,
Ser. Khim. 1989, 11, 2613–2616. (d) Grosse, J.; Martin, R. Z. Anorg. Allg.
Chem. 1992, 607, 146–152.
(10) (a) Agou, T.; Kobayashi, J.; Kawashima, T. Org. Lett. 2005, 7,
4373–4376. (b) Agou, T.; Kobayashi, J.; Kawashima, T. Inorg. Chem. 2006,
45, 9137–9144.
(11) Bebbington, M. W. P.; Bontemps, S.; Bouhadir, G.; Bourissou, D.
Angew. Chem., Int. Ed. 2007, 46, 3333–3336.
(19) trans-Ph2P-CHdCH-BMes2 was prepared efficiently by hydrobo-
ration of the alkynyldiphenylphosphine: Yuan, Z.; Taylor, N. J.; Marder,
T. B.; Williams, I. D.; Kurtz, S. K.; Cheng, L.-.T. J. Chem. Soc., Chem.
Commun. 1990, 1489–1492.
(12) For a brief overview of the known phosphine-borane derivatives,
see: Braunschweig, H.; Dirk, R.; Ganter, B. J. Organomet. Chem. 1997,
545–546, 257–266.
(13) For p-Ph2P-(C6H4)-BMes2, see: Yuan, Z.; Taylor, N. J.; Sun, Y.;
Marder, T. B.; Williams, I. D.; Cheng, L.-T. J. Organomet. Chem. 1993,
449, 27–37.
(20) During the preparation of this paper, Erker, Stephan, and co-workers
reported the hydroboration of Mes2P. (vinyl) with HB(C6F5)2. According
to spectroscopic data, the resulting phosphine-borane adopts a four-
membered-ring structure, as the result of intramolecular PfB interaction.9d
(21) Braun, M. J.; Champetier, M. G. C. R. Acad. Sci. Paris 1965, 260,
218–220.
(14) For diphosphine- and triphosphine-boranes featuring o-C6H4
linkers, see: Bontemps, S.; Bouhadir, G.; Dyer, P. W.; Miqueu, K.;
Bourissou, D. Inorg. Chem. 2007, 46, 5149–5151.
(15) PBderivativesassembledaroundmoreorlessflexiblephenyl-X-phenyl
spacers (X ) O, S) have also been investigated recently. See refs 2f,g and:
Bebbington, M. W. P.; Bontemps, S.; Bouhadir, G.; Bourissou, D. Eur. J.
Org. Chem. 2007, 4483–4486.
(22) Radical hydrophosphination of Me3NfB. (vinyl)3 with Me2PH led
to the spectroscopic characterization of the triphosphine-borane
B(CH2CH2PMe2)3: Grosse, J.; Lütke-Brochtrup, K.; Krebs, B.; Läge, M.;
Niemeyer, H.-H.; Würthwein, E.-U. Z. Naturforsch., B 2006, 61, 882–895.
(23) Schmidbaur, H.; Sigl, M.; Schier, A. J. Organomet. Chem. 1997,
529, 323–327.
(16) For monophosphine- and diphosphine-boranes featuring
a
-CH2- linker, see: (a) Rathke, J.; Schaeffer, R. Inorg. Chem. 1972, 11,
1150–1151. (b) Thomas, J. C.; Peters, J. C. Polyhedron 2004, 23, 2901–
2913.
(24) Only RPh2PfBH3 adducts have been obtained so far in the reaction
of Ph2P-(CH2)n-CHdCH2 (n ) 0, 1, 2) with BH3.23

1142 Organometallics, Vol. 27, No. 6, 2008
Vergnaud et al.
Scheme 2. Synthesis of the Neutral (2a,b) and Cationic (3a,b)
Ruthenium Complexes
Indeed, the 31P NMR chemical shift (δ –8.9 in CD2Cl2) is very
similar to that of Ph2PEt (δ –11.7 in C6D6), and a broad signal
is observed at δ +81.8 in the 11B NMR spectrum, as expected
for a trialkylborane. The reaction was found to be totally
regioselective, the introduction of the boron atom at the terminal
carbon atom being unambiguously deduced from the H/13C
1
Figure 1. Molecular view of 2b in the solid state (thermal ellipsoids
at the 30% probability level), with hydrogen atoms and solvate
molecules omitted. Selected bond lengths (Å) and bond angles
(deg): P1–Ru1 ) 2.352(2), Ru1–Cl1 ) 2.4003(19), Ru1–Cl2 )
2.4106(18), P1–C1 ) 1.841(7), C1–C2 ) 1.526(9), C2–B1 )
1.565(11); Cl1–Ru1–Cl2 ) 86.73(7), P1–Ru1–Cl1 ) 87.72(7),
P1–Ru1–Cl2 ) 85.78(7).
signals attributable to the CH2CH2 spacer. In our hands, 9-BBN
was also found to readily react with vinyldiphenylphosphine,
although more drastic conditions (10 h at 60 °C) were necessary.
The resulting phosphine-borane 1b was isolated in 89% yield.
Its monomeric open structure was substantiated by the similarity
of its NMR data (δ(31P) -10.4, δ(11B) +87.4) with those of
1a. The absence of any PfB interaction in the PCH2CH2B
derivatives 1a,b markedly contrasts with the closed form adopted
by the related P(CH2)nB (n ) 3, 4) compounds23 and is most
likely disfavored by the ring strain it would induce, although
related four-membered PC2B rings have been found to be
accessible with the o-C6H4 spacer.14,25
Coordination of Ligands 1a,b to the [(p-cymene)RuCl2]
Fragment.X-rayStructureof[(p-cymene)RuCl2{Ph2PCH2CH2(9-
BBN)}] (2b). Very recently, we have reported the synthesis of
the new NB ambiphilic ligand (2-picolyl)BCy2 and its coordina-
tion to the (p-cymene)RuCl2 fragment via a coordination mode
of type II (see Chart 1).2h This prompted us to investigate the
behavior of the PB ligands toward the same ruthenium fragment.
The dimer [(p-cymene)RuCl2]2 is readily cleaved by 1a,b in
1 h at room temperature (Scheme 2). The resulting complexes
[(p-cymene)RuCl2(Ph2PCH2CH2BR2)] (BR2 ) BCy2 (2a), 9-BBN
(2b)) were isolated in very good yields as red solids and were
fully characterized by multinuclear NMR spectroscopy and
elemental analysis. The coordination of the phosphorus atom
to ruthenium was indicated by the shift to lower field of the
31P NMR resonances (2a, δ +28.9; 2b, δ +27.2). The 11B NMR
signals (2a, δ +81.7; 2b, δ +86.3) showed that the borane
moiety does not participate in the coordination, ruling out the
presence of any RufB or Ru-ClfB interactions. This situation
was confirmed by an X-ray diffraction study performed on 2b
(Figure 1, Table 1). Although the modest quality of the
crystallographic data precludes a detailed discussion of the
geometric parameters, it is clear that the borane moiety remains
pendant1,7 and that the overall structure of 2b very much
resembles those of the borane-free complexes [(p-cymene)RuCl2-
(phosphine)].26
Table 1. Crystallographic Data for Complexes 2b and 4
2b
4
empirical formula
formula wt
cryst syst
space group
a, Å
C32H42BCl2PRu · CH2Cl2
C24H28ClPRu
483.95
725.33
orthorhombic
Pbca
17.312(4)
13.681(3)
28.015(6)
90
90
90
6635(3)
8
1.452
triclinic
j
P1
7.9420(4)
11.1756(5)
13.0715(6)
77.024(4)
73.311(4)
82.677(4)
1080.47(9)
2
1.488
0.93
11 845
6909
b, Å
c, Å
R, deg
ꢀ, deg
γ, deg
V, Å3
Z
calcd density, Mg/m3
abs coeff, mm–1
no. of rflns collected
no. of indep rflns
R1 (I > 2σ(I))
wR2
0.865
41 322
6774
0.0766
0.1300
2.334 and -0.815
0.0316
0.0545
0.945 and -0.937
(∆/r)max (e Å–3
)
likely explain this difference. This highlights that subtle stereo-
electronic effects may have a noticeable influence on the coordina-
tion of ambiphilic ligands. From a synthetic viewpoint, the reverse
sequence of coordination followed by hydroboration proved to
be much less efficient. Indeed, 9-BBN does not react with
[(p-cymene)RuCl2(Ph2PCHdCH2)] at room temperature and
only leads to complex mixtures at 70 °C.27
Chloride Abstraction and Access to the Four-Membered
Ruthenacycle [(p-cymene)RuCl(KC,P-CH2CH2PPh2)] (4). A
rich chemistry has been gained from chloride abstraction of [(p-
cymene)RuCl2(L)] derivatives with some interesting catalytic
applications.28 Our first attempt to prepare cationic complexes
by treating 2a,b with silver tetrafluoroborate was successful.
The reactions were performed at room temperature in dichlo-
This situation is in marked contrasts with the Ru-ClfB
interaction found for the related NB ligand in [(p-cymene)RuCl2((2-
picolyl)BCy2)].2h The higher rigidity and lower steric demand of
the 2-picolyl moiety compared to the Ph2PCH2CH2 group most
(27) A previous example of hydroboration of alkenylphosphines in the
coordination sphere of a metal was reported to only give complex
mixtures: Coles, S. J.; Faulds, P.; Hurthouse, M. B.; Kelly, D. G.; Ranger,
G. C.; Toner, A. J.; Walker, N. M. J. Organomet. Chem. 1999, 586, 234–
240.
(25) Note also that the (2-picolyl)(dicyclohexyl)borane was found to
adopt a head-to-tail dimeric structure in the solid state (as the result of
intermolecular NfB interactions) and to equilibrate in solution with a
strained monomeric structure (intramolecular NfB interaction).2h
(26) For selected examples, see: (a) Gupta, D. K.; Sahay, A. N.; Pandey,
D. S.; Jha, N. K.; Sharma, P.; Espinosa, G.; Cabrera, A.; Puerta, M. C.;
Valerga, P. J. Organomet. Chem. 1998, 568, 13–20. (b) McQuade, P.; Rath,
N. P.; Barton, L. Inorg. Chem. 1999, 38, 5468–5470. (c) Chaplin, A. B.;
Scopelliti, R.; Dyson, P. J. Eur. J. Inorg. Chem. 2005, 4762–4774.
(28) (a) Gimeno, J.; Cadierno, V.; Crochet, P. In ComprehensiVe
Organometallic Chemistry; Mingos, D. M. P., Crabtree, R. H., Bruce, M.,
Eds.; Elsevier: Amsterdam, 2007; Vol. 6, Chapter 14. (b) Ball, Z. T. In
ComprehensiVe Organometallic Chemistry; Mingos, D. M. P., Crabtree,
R. H., Ojima, I. , Eds.; Elsevier: Amsterdam, 2007; Vol. 10, Chapter 17.

Ru Arene Complexes with Ph2PCH2CH2BR2 Ligands
Organometallics, Vol. 27, No. 6, 2008 1143
Scheme 3. Synthesis and Reactivity of the Four-Membered
Ruthenacycle 4
romethane in the presence of a slight excess of acetonitrile to
stabilize the ruthenium center by reaching a 18-electron con-
figuration. After standard workup, the cationic complexes [(p-
cymene)RuCl(Ph2PCH2CH2BR2)(CH3CN)][BF4] (3a,b) were
isolated in good yields as yellow powders. As expected,29
formation of the cationic complexes is accompanied by a low-
field 31P NMR shift of about 5 ppm. The coordination of one
molecule of acetonitrile to the ruthenium center was clearly
1
apparent from the H and 13C NMR signals observed for the
CH3CN coligand (δ(1H) ∼2.4, δ(13C) ∼4 ppm). In addition,
the four distinct signals observed for the aromatic protons of
the p-cymene were consistent with the presence of a stereogenic
Ru center.30 Lastly, the broad signals observed at ∼85 ppm in
the 11B NMR spectra unambiguously indicated the retention of
the pendant borane moiety.
Figure 2. Molecular view of 4 in the solid state (thermal ellipsoids
at the 30% probability level), with hydrogen atoms omitted. Selected
bond lengths (Å) and bond angles (deg): P1–Ru1 ) 2.2821(6),
Ru1–Cl1 ) 2.4271(5), Ru1–C2 ) 2.146(2), P1–C1 ) 1.811(2),
C1–C2 ) 1.539(3); Cl1–Ru1–C2 ) 85.17(6), P1–Ru1–Cl1 )
88.66(2), P1–Ru1–C2 ) 66.75(6), Ru1–C2–C1 ) 103.23(13),
P1–C1–C2 ) 93.05(13), C1–P1–Ru1 ) 89.98(7).
Interestingly, chloride abstraction turned to be very much
dependent on the nature of the silver salt. When the basic salt
AgOAc was used in place of AgBF4, the ruthenium complexes
2a,b afforded the new complex [(p-cymene)RuCl(κC,P-CH2-
CH2PPh2)] (4), isolated as a yellow powder in 61% yield. 4 is
formulated as a four-membered metallacycle on the basis of
NMR and X-ray data (Scheme 3, Table 1). The 31P NMR signal
for 4 (δ -21.6) is shielded to higher field by about 50 ppm
compared to those of the neutral precursors. The absence of
any 11B NMR signal indicates the elimination of the borane
group, in agreement with the formation of the unique complex
4, whatever the borane substituent of the starting complex. The
signal observed at δ -3.6 (JPC ) 53 Hz) in the 13C NMR
spectrum of 4 suggests the formation of an original four-
membered ruthenacycle. Indeed, a few related ruthenacycles
have been reported,31 and all of them exhibit a 13C NMR signal
near 0 ppm for the CH2Ru unit.31b–e Single crystals of complex
4 were grown upon allowing a THF/pentane solution to stand
at 4 °C for several days, and its structure was confirmed by an
X-ray diffraction analysis (Figure 2). In the solid state, the four-
membered ring noticeably deviates from planarity (P-C-C-Ru
torsion angle of 23.1°). The P-Ru-C bond angle is the most
acute among the endocyclic angles (66.7°), and the P-Ru and
C-Ru bond lengths are 2.2821(6) and 2.146(2) Å, respectively.
Overall, the geometric parameters measured for 4 fall in the
middle range of those found in the few structurally characterized
four-membered ruthenacycles.31d–g
followed by nucleophilic attack of the terminal CH2 group to
the ruthenium center, the elimination of the chlorine being
assisted by the silver cation.32 Two alternative sequences are
also plausible: (i) halide abstraction followed by nucleophilic
attack by acetate at boron and zwitterion pair collapse with loss
of R2BOAc or (ii) halide abstraction, followed by acetate
coordination to ruthenium and intramolecular R2BOAc elimina-
tion. Known four-membered ruthenacycles were typically
obtained from highly unsaturated complexes via C-H activation
of an iPr or tBu group at phosphorus. The formation of 4 provides
an alternative route relying on the activation of the borane moiety
of an ambiphilic ligand. In this regard, it is noteworthy that 4 was
not observed when the related borane-free complex [(p-cymene)-
RuCl2(Ph2PEt)] was reacted with AgOAc.
Reactivity of the Four-Membered Ruthenacycle 4. The
behavior of the ruthenacycle 4 toward Lewis acids was studied.
Chlorodicyclohexylborane was found to slowly react in THF
at room temperature to quantitatively give back the neutral
complex 2a. The ring opening of the ruthenacycle provides a
new synthetic route to PCH2CH2B complexes and most probably
proceeds via σ-bond metathesis. Alternatively, one may consider
the electrophilic addition of the chloroborane with cleavage of
the Ru-C bond and subsequent transfer of the chloride from
boron to ruthenium.
The formation of 4 may result from the initial addition of
the acetate to the boron atom, leading to an ate complex,
As a first evaluation of the influence of the Lewis acid, an
NMR in situ experiment was performed by adding chlorodi-
ethylalane to the ruthenacycle 4 in THF-d8. In this case,
complete conversion of 4 required heating at 50 °C for 24 h.
31P NMR monitoring revealed the formation of the new complex
5 with retention of the four-membered ruthenacycle (δ(31P)
-13.3). On the basis of multinuclear NMR data, 5 can be
formulated as the ethyl complex [(p-cymene)RuEt(κC,P-CH2-
(29) Jung, S.; Ilg, K.; Brandt, C. D.; Wolf, J.; Werner, H. Dalton Trans.
2002, 318–327.
(30) Chaplin, A. B.; Fellay, C.; Laurenczy, G.; Dyson, P. J. Organo-
metallics 2007, 26, 586–593.
(31) (a) Kletzin, H.; Werner, H. Angew. Chem., Int. Ed. 1983, 22, 873–
874. (b) Bennett, M. A.; Huang, T.-N.; Latten, J. L. J. Organomet. Chem.
1984, 272, 189–205. (c) Werner, H.; Kletzin, H.; Roder, K. J. Organomet.
Chem. 1988, 355, 401–417. (d) Campion, B. K.; Heyn, R. H.; Tilley, T. D.;
Rheingold, A. L. J. Am. Chem. Soc. 1993, 115, 5527–5537. (e) Liu, S. H.;
Lo, S. T.; Wen, T. B.; Williams, I. D.; Zhou, Z. Y.; Lau, C. P.; Jia, G.
Inorg. Chim. Acta 2002, 334, 122–130. (f) Amoroso, D.; Haaf, M.; Yap,
G. P. A.; West, R.; Fogg, D. E. Organometallics 2002, 21, 534–540. (g)
Walstrom, A.; Pink, M.; Tsvetkov, N. P.; Fan, H.; Ingleson, M.; Caulton,
K. G. J. Am. Chem. Soc. 2005, 127, 16780–16781.
(32) Somewhat related processes have been reported by Tilley and
Fontaine for the rearrangement of [PhB(CH2P-i-Pr2)3Rh(PMe3)2] and
[Cp*RhMe2(Me2PCH2AlMe2)], respectively. See: Turculet, L.; Feldman,
J. D.; Tilley, D. Organometallics 2004, 23, 2488–2502, and ref 8b.

1144 Organometallics, Vol. 27, No. 6, 2008
Vergnaud et al.
groscopic, but the purity could be easily checked by multinuclear
NMR (NMR tube prepared in a drybox). Yield: 1.63 g (96%).
31P{1H} NMR (162 MHz, CD2Cl2): δ -8.91. 1H NMR (400 MHz,
CD2Cl2): δ 7.46 (m, 4H, HPh), 7.37 (m, 6H, HPh), 2.08 (m, 2H,
H2CP), 1.12–1.77 (m, 24H, H2CB and HCy). 13C{1H} NMR (101
MHz, CD2Cl2): CPh not observed, δ 132.74 (d, JC,P ) 29.2 Hz,
CHPh), 128.38 (s, CHPh), 128.28 (d, JC,P ) 6.4 Hz, CHPh), 35.74 (s
broad, BCH), 27.53 (s, CH2Cy), 27.12 (s, CH2Cy), 27.03 (s, CH2Cy),
21.32 (d, 1JC,P ) 13.4 Hz, H2CP), 19.69 (s broad, H2CB). 11B{1H}
NMR (128 MHz, CD2Cl2): δ 81.8. Anal. Calcd for C26H36PB: C,
80.00; H, 9.30. Found: C, 80.74; H, 8.69.
Preparation of Ph2PCH2CH2(9-BBN) (1b). Vinyldiphenylphos-
phine (707 mg, 97%, 3.23 mmol) and 9-borabicyclo[3.3.1]nonane
(396 mg, 3.24 mmol) were stirred in THF (20 mL) for 10 h at 60
°C. The solvent was then removed under vacuum, affording
Ph2PCH2CH2(9-BBN) as a white solid. The solid was washed with
5 mL of pentane and dried under vacuum. The finely divided solid
is extremely hygroscopic, but the purity could be easily checked
by multinuclear NMR (NMR tube prepared in a drybox).Yield: 958
mg (89%). 31P{1H} NMR (101 MHz, CD2Cl2): δ -10.44. 1H NMR
(250 MHz, CD2Cl2): δ 7.49 (m, 4H, HPh), 7.36 (m, 6H, HPh), 2.29
(m, 2H, H2CP), 1.25–1.92 (m, 16H, H2CB and H9-BBN). 13C{1H}
CH2PPh2)]. Retention of the four-membered ruthenacycle is
indicated by the diagnostic signal observed in 13C NMR for
the CH2Ru unit (δ -9.6, JPC ) 52 Hz). Substitution of the
chlorine atom at ruthenium by an ethyl group is apparent from
1H and 13C NMR data and is further corroborated by 2D
experiments and 1D TOCSY {31P}. The reaction with the
chloroalane proceeds via a RuCl/AlEt redistribution process,
leading to alkylation at ruthenium with retention of the four-
membered metallacycle. At this stage, it is difficult to precisely
identify the factors that explain the different behavior observed
toward ClBCy2 and ClAlEt2, since the nature of both the group
13 element and the alkyl substituents may play a role.
Conclusion
Two representative ambiphilic PB ligands incorporating a
flexible -CH2CH2- linker have been prepared by simple
hydroboration of a vinylphosphine. Their coordination to the
(p-cymene)RuCl2 fragment provides rare examples of complexes
featuring pendant Lewis acids, in marked contrast with what
we have recently observed when using NB ligands (2-pico-
lylboranes). By using AgBF4 as chloride abstractor, the corre-
sponding cationic species 3a,b were obtained without alteration
of the pendant borane moieties. In contrast, AgOAc promotes
the activation of the CH2-B bond of the coordinated PB ligands,
leading to the original four-membered ruthenacycle 4. Interest-
ingly, 4 displays a versatile reactivity toward Lewis acids: (i)
with ClBCy2, the ambiphilic PB ligand is reformed in the
coordination sphere of the metal and the neutral complex 2a is
recovered; (ii) with ClAlEt2, alkylation at ruthenium with
retention of the ruthenacycle is achieved.
NMR (63 MHz, CD2Cl2): CPh not observed, δ 132.71 (d, JC,P
)
18.2, CHPh), 128.36 (s, CHPh), 128.31 (d, JC,P ) 10.0 Hz, CHPh),
33.20 (s, H2C9-BBN), 31.17 (s broad, HC9-BBN), 23.23 (s broad, H2CB
1
and H2C9BBN), 22.08 (d, JC,P ) 11.3 Hz, H2CP). 11B{1H} NMR
(160 MHz, CDCl3): δ 87.4. Anal. Calcd for C22H28PB: C, 79.06;
H, 8.44. Found: C, 78.26; H, 8.98.
Preparation of [(p-cymene)RuCl2(Ph2PCH2CH2BCy2)] (2a).
[(p-cymene)RuCl2)]2 (683 mg, 1.12 mmol) and Ph2PCH2CH2BCy2
(885 mg, 2.27 mmol) were stirred in CH2Cl2 (15 mL) for 1 h. The
solvent was then removed under vacuum, and the red solid that
was obtained was washed with pentane. Yield: 1.55 g (99%).
31P{1H} NMR (121 MHz, CD2Cl2): δ 28.92. 1H NMR (300 MHz,
Ongoing efforts aim at further expanding the variety of ambi-
philic compounds and at gaining more insights into the behavior
of Lewis acids in the coordination sphere of transition metals.
CD2Cl2): δ 7.92 (m, 4H, HPh), 7.54 (m, 6H, HPh), 5.26 (d, 3JH,H
)
6.0 Hz, 2H, Hp-cym), 5.10 (d, 3JH,H ) 6.0 Hz, 2H, Hp-cym), 2.50 (m,
3H, HCi-Pr and H2CP), 1.88 (s, 3H, H3C), 0.84 (d, 3JH,H ) 6.9 Hz,
6H, H3Ci-Pr), 0.88–1.70 (m, 24H, H2CB and HCy). 13C{1H} NMR
(75 MHz, CD2Cl2): δ 133.55 (d, JC,P ) 8.3 Hz, CHPh), 132.73 (d,
1JC,P ) 41.5 Hz, CPh), 130.34 (d, JC,P ) 2.3 Hz, CHPh), 128.04 (d,
JC,P ) 9.1 Hz, CHPh), 107.33 (s, Cp-cym), 93.46 (s, Cp-cym), 90.53 (s,
Experimental Section
General Procedures. All reactions were performed using
standard Schlenk or glovebox techniques under an argon atmo-
sphere. NMR spectra were recorded on Bruker ARX 250, DPX
300, Avance 300, Avance 400 and Avance 500 spectrometers. 11B,
31P, 1H, and 13C chemical shifts are expressed with a positive sign,
in parts per million, relative to external BF3 · Et2O, 85% H3PO4,
and residual 1H and 13C solvent signals, respectively. Unless
otherwise stated, NMR spectra were recorded at 293 K. Elemental
analyses were performed at the LCC on a Perkin-Elmer 2400 (II)
elemental analyzer. In the cases of 1a,b, V2O5 was introduced into
the samples for better combustion.
Materials and Methods. CH2Cl2, pentane, and CH3CN were
dried over CaH2, and THF was dried over sodium/benzophenone
and distilled prior to use. All organic reagents were obtained from
commercial sources and used as received, [(p-cymene)RuCl2]2,33
dicyclohexylborane,34 and 9-borabicyclo[3.3.1]nonane35 were pre-
pared according to literature procedures.
Preparation of Ph2PCH2CH2BCy2 (1a). Vinyldiphenylphos-
phine (947 mg, 97%, 4.33 mmol), and dicyclohexylborane (795
mg, 4.47 mmol) were stirred in THF (10 mL) for 1 h at room
temperature. The solvent was then removed under vacuum, afford-
ing Ph2PCH2CH2BCy2 as a white solid. Extraction with 20 mL of
pentane was performed. Filtration and evaporation under vacuum
led to a white finely divided solid. The solid is extremely hy-
CHp-cym), 85.50 (s, CHp-cym), 35.61 (s, BCH), 29.96 (s, HCi-Pr), 27.32
1
(s, H2CCy), 26.93 (s, H2CCy), 21.03 (s, H3Ci-Pr), 17.43 (d, JC,P
)
24.7 Hz, H2CP), 17.07 (s, H3C), 16.21 (s broad, H2CB). 11B{1H}
NMR (75 MHz, CD2Cl2): δ 81.7. Anal. Calcd for C36H50RuCl2PB:
C, 62.07; H, 7.25. Found: C, 61.52; H, 6.65.
Preparation of [(p-cymene)RuCl2{Ph2PCH2CH2(9-BBN)}]
(2b). [(p-cymene)RuCl2]2 (524 mg, 0.86 mmol) and Ph2PCH2CH2(9-
BBN) (572 mg, 1.71 mmol) were stirred in CH2Cl2 (15 mL) for
1 h. The solvent was then removed under vacuum, and the red
solid that was obtained was washed with pentane. Yield: 920 mg
(84%). Crystals suitable for X-ray crystallography were obtained
by slow evaporation of a CH2Cl2 solution at room temperature.
31P{1H} NMR (162 MHz, CD2Cl2): δ 27.23. 1H NMR (400 MHz,
CD2Cl2): δ 7.91 (m, 4H, HPh), 7.53 (m, 6H, HPh), 5.27 (d, 3JH,H
)
3
6.4 Hz, 2H, Hp-cym), 5.11 (d, JH,H ) 6.4 Hz, 2H, Hp-cym), 2.73
(pseudoquad, 2JH,P ) 3JH,H ) 8.0 Hz, 2H, H2CP), 2.50 (sept, 3JH,H
) 7.2 Hz, 1H, HCi-Pr), 1.90 (s, 3H, H3C), 1.18 (m, 2H, H2CB),
0.85 (d, 3JH,H ) 7.2 Hz, 6H, H3Ci-Pr), 0.90–1.77 (m, 14H, H9-BBN).
13C{1H} NMR (101 MHz, CD2Cl2): δ 133.68 (d, JC,P ) 8.3 Hz,
CHPh), 132.95 (d, 1JC,P ) 41.8 Hz, CPh), 130.32 (d, JC,P ) 2.3 Hz,
CHPh), 128.12 (d, JC,P ) 9.2 Hz, CHPh), 107.40 (s,Cp-cym), 93.54
(s, Cp-cym), 90.48 (s, CHp-cym), 85.58 (s, CHp-cym), 33.04 (s, H2C9-
BBN), 31.04 (s, HC9-BBN), 29.99 (s, HCi-Pr), 23.04 (s, H2C9-BBN),
(33) Bennet, M. A.; Huang, T.-N.; Matheson, T. W.; Smith, A. K. Inorg.
Synth. 1982, 21, 75.
(34) Smith, K. In Organometallics in Synthesis: A Manual; Schlosser,
M., Ed.; Wiley: New York, 2004; p 473.
1
21.06 (s, H3Ci-Pr), 20.28 (s, H2CB), 18.24 (d, JC,P ) 26.7 Hz,
H2CP), 17.10 (s, H3C). 11B{1H} NMR (128 MHz, CD2Cl2): δ 86.3.
(35) Soderquist, J. A.; Negron, A. Org. Synth. 1992, 70, 169–176.
Anal. Calcd for C33H44RuCl4PB (consistent with one molecule of

Ru Arene Complexes with Ph2PCH2CH2BR2 Ligands
Organometallics, Vol. 27, No. 6, 2008 1145
CH2Cl2 for each molecule of [(p-cymene)RuCl2{Ph2PCH2CH2B(9-
BBN)}] present in the crystalline state): C, 54.64; H, 6.13. Found:
C, 54.64; H, 5.70.
X-ray crystallography were obtained by keeping a saturated solution
of [(p-cymene)RuCl(κC,P-CH2CH2PPh2)] (4) in a THF/pentane
mixture at 4 °C for several days. Yield: 230 mg (60%). 31P{1H}
NMR (101 MHz, CDCl3): δ -21.61. 1H NMR (250 MHz, CDCl3):
Preparation of [(p-cymene)RuCl(Ph2PCH2CH2BCy2)(CH3-
CN)][BF4] (3a). To a mixture of [(p-cymene)RuCl2(Ph2PCH2-
CH2BCy2)] (466 mg, 0.67 mmol) and silver tetrafluoroborate (136
mg, 0.70 mmol), protected from the light, was added a solution of
acetonitrile (45 mg, 1.10 mmol) in CH2Cl2 (10 mL). A precipitate
quickly appeared, while the initially red solution turned orange.
The mixture was stirred for 1 h and then filtered, and the solvent
was removed under vacuum. The resulting yellow solid was washed
with pentane and dried in vacuo. Yield: 408 mg (77%). 31P{1H}
NMR (162 MHz, CD2Cl2): δ 32.87. 1H NMR (400 MHz, CD2Cl2):
3
δ 7.69 (m, 2H, HPh), 7.42 (m, 8H, HPh), 5.02 (d, JH,H ) 5.5 Hz,
1H, Hp-cym), 4.94 (d, 3JH,H ) 6.5 Hz, 1H, Hp-cym), 4.91 (d, 3JH,H
)
6.5 Hz, 1H, Hp-cym), 4.32 (d, 3JH,H ) 5.5 Hz, 1H, Hp-cym), 3.85 (m,
1H, HCHP), 3.48 (m, 1H, HCHP), 2.73 (sept, 3JH,H ) 7.0 Hz, 1H,
HCi-Pr), 2.14 (m, 1H, HCHRu), 1.96 (m, 4H HCHRu and H3C),
1.27 (d, 3JH,H ) 7.0 Hz, 3H, H3Ci-Pr), 1.24 (d, 3JH,H ) 7.0 Hz, 3H,
H3Ci-Pr). 13C{1H} NMR (100 MHz, CDCl3): CPh not observed, δ
133.84 (d, JC,P ) 11.0 Hz, CHPh), 130.64 (d, JC,P ) 9.7 Hz, CHPh),
130.24 (s, CHPh), 129.17 (s, CHPh), 128.47 (d, JC,P ) 9.2 Hz, CHPh),
128.07 (d, JC,P ) 9.9 Hz, CHPh), 112.44 (s, Cp-cym), 97.54 (s, Cp-
cym), 87.12 (s, CHp-cym), 85.35 (s, CHp-cym), 83.38 (s, CHp-cym), 81.87
3
δ 7.75 (m, 4H, HPh), 7.63 (m, 6H, HPh), 5.74 (d, JH,H ) 5.6 Hz,
1H, Hp-cym), 5.56 (d, 3JH,H ) 5.6 Hz, 1H, Hp-cym), 5.27 (d, 3JH,H
)
1
(s, CHp-cym), 37.21 (d, JC,P ) 32.8 Hz, H2CP), 31.10 (s, HCi-Pr),
6.0 Hz, 1H, Hp-cym), 5.09 (d, 3JH,H ) 6.0 Hz, 1H, Hp-cym), 2.62 (sept,
3JH,H ) 7.2 Hz, 1H, HCi-Pr), 2.55 (m broad, 2H, H2CP), 2.42 (s,
3H, H3CCN), 2.00 (s, 3H, H3C), 1.15 (d, 3JH,H ) 7.2 Hz, 3H, H3Ci-
Pr), 1.06 (d, 3JH,H ) 7.2 Hz, 3H, H3Ci-Pr), 0.93-1.69 (m, 24H, H2CB
and HCy). 13C{1H} NMR (101 MHz, CD2Cl2): CPh and CN
(acetonitrile) not observed, δ 133.70 (d, JC,P ) 9.2 Hz, CHPh),
132.21 (d, JC,P ) 8.3 Hz, CHPh), 131.62 (d, JC,P ) 2.2 Hz, CHPh),
131.40 (d, JC,P ) 2.4 Hz, CHPh), 129.07 (d, JC,P ) 5.9 Hz, CHPh),
128.97 (d, JC,P ) 6.2 Hz, CHPh), 112.94 (s, Cp-cym), 99.52 (s, Cp-
cym), 92.39 (s, CHp-cym), 91.08 (s, CHp-cym), 90.54 (s, CHp-cym), 86.78
(s, CHp-cym), 35.63 (s, BCH), 30.77 (s, HCi-Pr), 27.34 (s, H2CCy),
26.88 (s, H2CCy). 26.85 (s, H2CCy), 21.58 (s, H3Ci-Pr), 21.49 (d, 1JC,P
) 26.2 Hz, H2CP), 21.29 (s, H3Ci-Pr), 17.82 (s, H3C), 17.54 (s,
H2CB), 3.98 (s, H3CCN). 11B{1H} NMR (128 MHz, CD2Cl2): δ
82.9. Anal. Calcd for C38H53RuClNPB2F4: C, 57.85; H, 6.77; N:
1.78. Found: C, 57.30; H, 6.13; N: 1.65.
2
23.79 (s, H3Ci-Pr), 22.42 (s, H3Ci-Pr), 18.06 (H3C), -3.56 (d, JC,P
) 53.2 Hz, H2CRu). Anal. Calcd for C24H28RuClP: C, 59.56; H,
5.84. Found: C, 59.12; H, 5.60.
Reaction of [(p-cymene)RuCl(KC,P-CH2CH2PPh2)] (4) with
ClBCy2. A solution of chlorodicyclohexylborane (12.9 mg, 0.061
mmol) in THF-d8 (ca. 0.5 mL) was added to 4 (25.0 mg, 0.052 mmol)
in a NMR tube, affording [(p-cymene)RuCl2(Ph2PCH2CH2BCy2)] (2a)
1
quantitatively (according to 31P, H, and 13C NMR) over one night.
Reaction of [(p-cymene)RuCl(KC,P-CH2CH2PPh2)] (4) with
ClAlEt2. A solution of chlorodiethylalane (5.5 mg, 0.046 mmol) in
THF-d8 (ca. 0.5 mL) was added to 4 (20.3 mg, 0.042 mmol) in a NMR
tube, affording [(p-cymene)Ru(CH2CH3)(κC,P-CH2CH2PPh2)] (5) over
1 day at 50 °C. Attempts to isolate complex 5 in pure form have so
far been unsuccessful, and the complex was therefore only character-
ized in situ. 31P{1H} NMR (121 MHz, THF-d8): δ -13.35. 1H NMR
(300 MHz, THF-d8): δ 7.30 (m, 10H, HPh), 4.94 (d, 3JH,H ) 5.7 Hz,
1H, Hp-cym), 4.77 (d, 3JH,H ) 5.7 Hz, 1H, Hp-cym), 4.72 (d, 3JH,H ) 5.7
Preparation of [(p-cymene)RuCl{Ph2PCH2CH2(9-BBN)}(CH3-
CN)][BF4] (3b). To a mixture of 2b (292 mg, 0.46 mmol) and
silver tetrafluoroborate (90 mg, 0.46 mmol), protected from the light,
was added a solution of acetonitrile (23 mg, 0.56 mmol) in CH2Cl2
(15 mL). A precipitate quickly appeared, while the initially red
solution turned orange. The mixture was stirred for 1 h and then
filtered, and the solvent was removed under vacuum. The resulting
yellow solid was washed with pentane and dried under vacuum.
Yield: 251 mg (74%). 31P{1H} NMR (121 MHz, CD2Cl2): δ 32.24.
1H NMR (300 MHz, CD2Cl2): δ 7.76 (m, 4H, HPh), 7.62 (m, 6H,
HPh), 5.70 (d, 3JH,H ) 6.0 Hz, 1H, Hp-cym), 5.53 (d, 3JH,H ) 6.0 Hz,
3
Hz, 1H, Hp-cym), 4.60 (d, JH,H ) 5.7 Hz, 1H, Hp-cym), 3.87 (m, 1H,
3
HCHP), 3.38 (m, 1H, HCHP), 2.53 (sept, JH,H ) 6.9 Hz, 1H, HCi-
Pr), 2.00 (s, 3H, H3Cp-cym), 1.57 (m, 2H, HCH(CH2P) and HCHEt),
3
3
1.40 (t, JH,H ) 7.5 Hz, 3H, H3CEt), 1.19 (d, JH,H ) 6.9 Hz, 3H,
3
H3Ci-Pr), 1.14 (d, JH,H ) 6.9 Hz, 3H, H3Ci-Pr), 0.74 (m, 1H,
HCH(CH2P)), 0.55 (m, 1H, HCHEt). 13C{1H} NMR (75 MHz, THF-
d8): CPh not observed, δ 132.86 (d, JC,P ) 11.0 Hz, CHPh), 130.39 (d,
JC,P ) 9.5 Hz, CHPh), 129.03 (d, JC,P ) 2.2 Hz, CHPh), 127.96 (d, JC,P
) 2.2 Hz, CHPh), 127.71 (d, JC,P ) 5.4 Hz, CHPh), 127.59 (d, JC,P
)
5.8 Hz, CHPh), 106.53 (d, JC,P ) 4.4 Hz, Cp-cym), 98.06 (d, JC,P ) 3.4
Hz, Cp-cym), 87.19 (d, JC,P ) 1.8 Hz, CHp-cym), 86.32 (d, JC,P ) 1.3
1H, Hp-cym), 5.31 (d, 3JH,H ) 6.0 Hz, 1H, Hp-cym), 5.14 (d, 3JH,H
)
3
6.0 Hz, 1H, Hp-cym) 2.72 (m, 2H, H2CP), 2.61 (sept, JH,H ) 6.9
Hz, CHp-cym), 83.87 (d, JC,P ) 4.5 Hz, CHp-cym), 83.54 (d, JC,P
)
Hz, 1H, HCi-Pr), 2.40 (s, 3H, H3CCN), 2.00 (s, H3C), 1.14 (d, 3JH,H
5.7 Hz, CHp-cym), 38.84 (d, JC,P ) 33.5 Hz, H2CP), 31.39 (s, HCi-Pr),
22.95 (s, H3Ci-Pr), 22.86 (d, JC,P ) 4.0 Hz, H3CEt), 22.79 (s, H3Ci-Pr),
3
) 6.9 Hz, 3H, H3Ci-Pr), 1.07 (d, JH,H ) 6.9 Hz, 3H, H3Ci-Pr),
1.19–1.84 (m, 16H, H2CB and H9-BBN). 13C{1H} NMR (75 MHz,
CD2Cl2): CPh, H2CB, and CN (acetonitrile) not observed, δ 133.60
(d, JC,P ) 9.1 Hz, CHPh), 132.31 (d, JC,P ) 8.3 Hz, CHPh), 131.53
(d, JC,P ) 3.0 Hz, CHPh), 131.38 (d, JC,P ) 2.3 Hz, CHPh), 129.11
(d, JC,P ) 1.5 Hz, CHPh), 128.98 (d, JC,P ) 2.3 Hz, CHPh), 112.81
(s, Cp-cym), 99.58 (s, Cp-cym), 92.47 (s, CHp-cym), 90.83 (s, CHp-cym),
90.30 (s, CHp-cym), 87.15 (s, CHp-cym), 33.02 (s, H2C9-BBN), 31.12
18.04 (s, H3Cp-cym), 5.31 (d, JC,P ) 15.1 Hz, H2CEt), -9.62 (d, JC,P
52.5 Hz, H2C(CH2P)).
)
Crystal Structure Determination of Complexes 2b and 4. Data
were collected at low temperature (110 K) on an Xcalibur Oxford
Diffraction diffractometer using graphite-monochromated Mo KR
radiation (λ ) 0.710 73 Å) and equipped with an Oxford Cryo-
systems Cryostream Cooler Device. The final unit cell parameters
were obtained by means of a least-squares refinement. The structures
have been solved by direct methods using SIR9236 and refined by
means of least-squares procedures on F2 with the aid of the program
SHELXL97,37 included in the software package WinGX version
1.63.38 The atomic scattering factors were taken from ref 39. All
hydrogen atoms were geometrically placed and refined by using a
riding model. All non-hydrogen atoms were anisotropically
1
(s, HC9-BBN), 30.78 (s, HCi-Pr), 23.00 (s, H2C9-BBN), 21.92 (d, JC,P
) 27.3 Hz, H2CP), 21.58 (s, H3Ci-Pr), 21.33 (s, H3Ci-Pr), 17.81 (s,
H3C), 3.94 (s, H3CCN). 11B{1H} NMR (75 MHz, CD2Cl2): δ 87.6.
Preparation of [(p-cymene)RuCl(KC,P-CH2CH2PPh2)] (4). In
a glovebox, to a solution of [(p-cymene)RuCl2{Ph2PCH2CH2(9-
BBN)}] (500 mg, 0.79 mmol) in THF (10 mL), stirred and protected
from the light, was slowly added silver acetate (131 mg, 0.78
mmol). The mixture was stirred for 2 h, during which time the
initially red solution turned yellow and a precipitate appeared.
The solution was then filtered and evaporated to dryness, and the
remaining oil was filtered over a small alumina column with CH2Cl2
as eluant. The yellow fractions were collected, and the solvent was
removed under vacuum, yielding a yellow oil which could be
obtained as a solid by trituration in pentane. Crystals suitable for
(36) Altomare, A.; Cascarano, G.; Giacovazzo, C.; Guagliardi, A.
SIR92-A program for crystal structure solution. J. Appl. Crystallogr. 1993,
26, 343–350.
(37) Sheldrick, G. M. SHELX97, Programs for Crystal Structure
Analysis (Release 97-2); Institüt für Anorganische Chemie der Universität,
Tammanstrasse 4, D-3400 Göttingen, Germany, 1998.

1146 Organometallics, Vol. 27, No. 6, 2008
Vergnaud et al.
refined, and in the last cycles of refinement a weighting scheme
was used, where weights are calculated from the following
Acknowledgment. We are grateful to the CNRS and
UPS for financial support of this work. J.V. acknowledges
the French Ministry “Education Nationale, Enseignement
Supérieur, Recherche” for his Ph.D. grant. S.S.-E. and
D.B. sincerely thank the reviewers for constructive
mechanistic considerations.
2
2
formula: w ) 1/[σ2(Fo ) + (aP)2 + bP], where P ) (Fo
+
2
2Fc )/3. Molecular drawing was performed with the program
ORTEP3240 with 30% probability displacement ellipsoids for
non-hydrogen atoms.
(38) Farrugia, L. WINGX-1.63, Integrated System of Windows Programs
for the Solution, Refinement and Analysis of Single Crystal X-Ray
Diffraction Data. J. Appl. Crystallogr. 1999, 32, 837–838.
(39) International Tables for X-Ray Crystallography; Kynoch Press:
Birmingham, England, 1974; Vol. 4.
Supporting Information Available: CIF files giving crystal-
lographic data for complexes 2b and 4. This material is available
free of charge via the World Wide Web at http://pubs.acs.org.
(40) Farrugia, L. J. ORTEP3 for Windows. J. Appl. Crystallogr. 1997,
30, 565.
OM701139A