Synthesis, reactivity and catalytic activity in transfer hydrogenation of ketones of ruthenium(II) and ruthenium(IV) complexes containing the novel N-thiophosphorylated iminophosphorane-phosphine ligands Ph2PCH2P{=NP(=S)(OR)2}Ph2 (R = Et, Ph)

Article abstract of DOI:10.1039/b305520e

Iminophosphorane-phosphines Ph₂PCH₂P{=NP(=S)(OR)₂}Ph₂ (R = Et 1a, Ph 1b) have been prepared by treatment of bis(diphenylphosphino)methane with an equimolar amount of thiophosphorylated azides (RO)₂P(=S)N₃. Dimers [{Ru(η⁶-p-cymene)(μ-Cl)Cl}₂] and [{Ru(η³:η³-C₁₀H₁₆) (μ-Cl)Cl}₂] react with a two-fold excess of 1a,b yielding the neutral complexes [Ru(η⁶-p-cymene)Cl₂ (κ¹-P-Ph₂PCH₂P{=NP(=S)(OR)₂} Ph₂)] (R = Et 2a, Ph 2b) and [Ru(η³:η³- C₁₀H₁₆)Cl₂(κ¹-P- Ph₂PCH₂P{=NP(=S)(OR)₂}Ph₂)] (R = Et 5a, Ph 5b), respectively. Treatment of 2a,b and 5a,b with one equivalent of AgSbF₆ affords the cationic species [Ru(η⁶-p-cymene) Cl(κ²-P,S-Ph₂PCH₂P{=NP(=S) (OR)₂}-Ph₂)][SbF₆] (R = Et 3a, Ph 3b) and [Ru(η³:η³-C₁₀H₁₆)Cl (κ²-P,S-Ph₂PCH₂P{=NP(=S) (OR)₂}Ph₂)][SbF₆] (R = Et 6a, Ph 6b), respectively. The structure of the cation of complex 6a has been confirmed by X-ray crystallography. The preference observed for the κ²-P,S- vs. κ²-P,N- coordination of 1a,b seems to be sterically controlled since theoretical calculations on the models [Ru(η⁶- C₆H₆)Cl(κ²-P,N-H₂ PCH₂P{=NP(=S)(OH)₂} H₂)]⁺ A and [Ru(η⁶-C₆H₆)Cl(κ²- P,S-H₂PCH₂P{=NP(=S)(OH)₂} H₂)]⁺ B show that isomer A is ca. 5.0 kcal mol^-1 more stable than B. Dicationic complexes [Ru (η⁶-p-cymene)(κ³-P,N,S-Ph₂PCH ₂P{=NP(=S)(OR)₂}Ph₂)] [SbF₆]₂ (R = Et 4a, Ph 4b) and [Ru(η³:η³-C₁₀ H₁₆)-(κ³-P,N,S-Ph₂PCH₂ P{=NP(=S)(OR)₂}Ph₂)][SbF₆]₂ (R = Et 7a, Ph 7b) have been obtained by treating 2a,b and 5a,b, respectively, with two equivalents of AgSbF₆. The reactivity of [Ru(η⁶-p- cymene)(κ³-P,N,S-Ph₂PCH₂P{=NP(=S)- (OEt)₂}Ph₂)][SbF₆]₂ 4a towards neutral and anionic ligands has been explored allowing the synthesis of complexes [Ru(η⁶-p-cymene)(L)(κ²-P,S- Ph₂PCH₂P{=NP(=S)(OEt)₂}Ph₂)] [SbF₆]₂ (L = N≡CMe 8, PMe₃ 9, PMe₂Ph 10, PMePh₂ 11) and [Ru(η⁶-p- cymene)X(κ²-P,S-Ph₂PCH₂P{=NP(=S) (OEt)₂}Ph₂)][SbF₆] (X = Br 12, I 13, N₃ 14), respectively. The catalytic activity of complexes 2-7a,b in transfer hydrogenation of ketones by propan-2-ol has been also studied.

Full text of DOI:10.1039/b305520e

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Synthesis, reactivity and catalytic activity in transfer
hydrogenation of ketones of ruthenium(II) and ruthenium(IV)
complexes containing the novel N-thiophosphorylated
iminophosphorane-phosphine ligands
Ph PCH P{᎐NP(᎐S)(OR) }Ph (R ؍ Et, Ph)†
᎐
᎐
2
2
2
2
Victorio Cadierno,*a Pascale Crochet,a Josefina Díez,a Joaquín García-Álvarez,a
Sergio E. García-Garrido,a Santiago García-Granda,b José Gimeno*a and
Miguel A. Rodríguez*c
a Departamento de Química Orgánica e Inorgánica, Instituto Universitario de Química
Organometálica “Enrique Moles” (Unidad Asociada al CSIC), Universidad de Oviedo,
E-33071 Oviedo, Spain. E-mail: vcm@sauron.quimica.uniovi.es; jgh@sauron.quimica.uniovi.es
b Departamento de Química Física y Analítica, Universidad de Oviedo, E-33071 Oviedo, Spain.
E-mail: sgg@sauron.quimica.uniovi.es
c Departamento de Química, Universidad de la Rioja, Grupo de Síntesis Química de La Rioja
(Unidad Asociada al CSIC), Madre de Dios 51, E-26006 Logroño, Spain.
E-mail: miguelangel.rodriguez@dq.unirioja.es
Received 16th May 2003, Accepted 25th June 2003
First published as an Advance Article on the web 14th July 2003
Iminophosphorane-phosphines Ph PCH P{᎐NP(᎐S)(OR) }Ph (R = Et 1a, Ph 1b) have been prepared by treatment
᎐
᎐
2
2
2
2
of bis(diphenylphosphino)methane with an equimolar amount of thiophosphorylated azides (RO) P(᎐S)N . Dimers
᎐
2
3
[{Ru(η6-p-cymene)(µ-Cl)Cl}2] and [{Ru(η3:η3-C10H16)(µ-Cl)Cl}2] react with a two-fold excess of 1a,b yielding the
neutral complexes [Ru(η6-p-cymene)Cl (κ1-P-Ph PCH P{᎐NP(᎐S)(OR) }Ph )] (R = Et 2a, Ph 2b) and [Ru(η3:η3-
᎐
᎐
2
2
2
2
2
C H )Cl (κ1-P-Ph PCH P{᎐NP(᎐S)(OR) }Ph )] (R = Et 5a, Ph 5b), respectively. Treatment of 2a,b and 5a,b with
᎐
᎐
10 16
2
2
2
2
2
one equivalent of AgSbF affords the cationic species [Ru(η6-p-cymene)Cl(κ2-P, S-Ph PCH P{᎐NP(᎐S)(OR) }-
᎐
᎐
6
2
2
2
Ph )][SbF ] (R = Et 3a, Ph 3b) and [Ru(η3:η3-C H )Cl(κ2-P, S -Ph PCH P{᎐NP(᎐S)(OR) }Ph )][SbF ] (R = Et 6a,
᎐
᎐
2
6
10 16
2
2
2
2
6
Ph 6b), respectively. The structure of the cation of complex 6a has been confirmed by X-ray crystallography. The
preference observed for the κ2-P, S - vs. κ2-P, N - coordination of 1a,b seems to be sterically controlled since theoretical
calculations on the models [Ru(η6-C H )Cl(κ2-P, N -H PCH P{᎐NP(᎐S)(OH) }H )]ϩ A and [Ru(η6-C H )Cl(κ2-P, S-
᎐
᎐
6
6
2
2
2
2
6
6
H PCH P{᎐NP(᎐S)(OH) }H )]ϩ B show that isomer A is ca. 5.0 kcal molϪ1 more stable than B. Dicationic complexes
᎐
᎐
2
2
2
2
[Ru(η6-p-cymene)(κ3-P, N, S -Ph PCH P{᎐NP(᎐S)(OR) }Ph )][SbF ] (R = Et 4a, Ph 4b) and [Ru(η3:η3-C H )-
᎐
᎐
2
2
2
2
6 2
10 16
(κ3-P, N, S-Ph PCH P{᎐NP(᎐S)(OR) }Ph )][SbF ] (R = Et 7a, Ph 7b) have been obtained by treating 2a,b and 5a,b,
᎐
᎐
2
2
2
2
6 2
respectively, with two equivalents of AgSbF . The reactivity of [Ru(η6-p-cymene)(κ3-P, N, S -Ph PCH P{᎐NP(᎐S)-
᎐
᎐
6
2
2
(OEt)2}Ph2)][SbF6]2 4a towards neutral and anionic ligands has been explored allowing the synthesis of complexes
6
2
᎐
[Ru(η -p-cymene)(L)(κ -P, S -Ph PCH P{᎐NP(᎐S)(OEt) }Ph )][SbF ] (L = N᎐CMe 8, PMe 9, PMe Ph 10, PMePh
᎐
᎐
᎐
2
2
2
2
6 2
3
2
2
11) and [Ru(η6-p-cymene)X(κ2-P, S -Ph PCH P{᎐NP(᎐S)(OEt) }Ph )][SbF ] (X = Br 12, I 13, N 14), respectively.
᎐
᎐
2
2
2
2
6
3
The catalytic activity of complexes 2–7a,b in transfer hydrogenation of ketones by propan-2-ol has been also studied.
Nevertheless, despite its great potential, their involvement in
Introduction
homogeneous catalysis still remains scarcely explored.11
Since its discovery in 1919,1 the imination reaction of tertiary
As part of our current work dealing with the chemistry
phosphines with organic azides, known as the Staudinger reac-
of ruthenium complexes containing R P–X–P(᎐NRЈ)R
᎐
2
2
tion, has been widely used for the preparation of imino-
ligands,10,11f we have recently reported the preparation of the
heterotrifunctional iminophosphorane-phosphines Ph2PCH2P-
{᎐NP(᎐O)(OR) }Ph (R = Et, Ph).12 These ligands have shown a
phosphoranes R P᎐N–RЈ.2 Such compounds usually act as
᎐
3
neutral monodentate ligands via the lone pair at the nitrogen
centre.3–5 Remarkably, the intrinsic coordinating ability of
iminophosphoranes, which are predominantly σ-donors with
only minor π-acceptor properties, is weak being easily
exchanged by other ligands such as phosphines, phosphites,
arsines, carbon monoxide or bipyridine.6
᎐
᎐
2
2
versatile coordination ability in ruthenium fragments adopting
κ1-P- (I), κ2-P, N - (II), κ2-P, O - (III) and κ3-P, N, O -coordination
modes (IV) (see Chart 1).
Although theoretical calculations (DFT level) on the model
complexes [Ru(η6-C H )Cl(κ2-P, N -H PCH P{᎐NP(᎐O)(OH) }-
᎐
᎐
᎐
᎐
6
6
2
2
2
The selective monoimination of bis-phosphines with azides
has been also successfully applied to the preparation of several
H2)]ϩ and [Ru(η6-C H )Cl(κ2-P, O -H PCH P{᎐NP(᎐O)(OH) }-
6
6
2
2
2
H2)]ϩ predicted that the κ2-P, N -isomers II are more stable than
their κ2-P, O -counterparts III, a marked preference for the
bidentate κ2-P, O -coordination, due probably to steric reasons,
was experimentally observed.12
iminophosphorane-phosphines R P–X–P(᎐NRЈ)R (X = dival-
᎐
2
2
ent bridging group).7 These heteroditopic P, N -ligands have led
to a host of new coordination and organometallic complexes.7,8
Moreover, the contrasting (e.g. hard/soft) reactivities of their
two donor centers confer on these ligands hemilabile properties
of interest from a reactivity and catalytic point of view.9,10
Continuing with these studies, in this paper we report on the
synthesis, reactivity and catalytic activity in transfer hydro-
genation of ketones of Ru() and Ru() complexes containing
the closely related N-thiophosphorylated iminophosphorane-
phosphine ligands Ph PCH P{᎐NP(᎐S)(OR) }Ph (R = Et 1a,
᎐
᎐
2
2
2
2
† Electronic supplementary information (ESI) available: analytical and
spectroscopic data. See http://www.rsc.org/suppdata/dt/b3/b305520e/
Ph 1b) in which the coordinating phosphoryl (RO) P᎐O substi-
᎐
2
D a l t o n T r a n s . , 2 0 0 3 , 3 2 4 0 – 3 2 4 9
T h i s j o u r n a l i s © T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 3
3240

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؍ Et 5a, Ph 5b). Treatment of the dimeric complexes [{Ru-
(η6-p-cymene)(µ-Cl)Cl}2]15 and [{Ru(η3:η3-C10H16)(µ-Cl)Cl}2]16
(C10H16 2,7-dimethylocta-2,6-diene-1,8-diyl) with two
=
equivalents of 1a,b, in dichlorometane at room temperature,
selectively affords the monomeric derivatives [Ru(η6-p-
cymene)Cl (κ1-P-Ph PCH P{᎐NP(᎐S)(OR) }Ph )] (R = Et 2a,
᎐
᎐
2
2
2
2
2
Ph 2b; Scheme 2) and [Ru(η3:η3-C10H16)Cl2(κ1-P-Ph2PCH2P-
{᎐NP(᎐S)(OR) }Ph )] (R = Et 5a, Ph 5b; Scheme 3), res-
᎐
᎐
2
2
pectively, which have been isolated as air-stable orange
microcrystalline solids in very good yields (89–98%).
Chart
1 Coordination modes of iminophosphorane-phosphine
ligands Ph2PCH2P{᎐NP(᎐O)(OR)2}Ph2 in ruthenium fragments.
᎐
᎐
tuents have been replaced by the softer thiophosphoryl (RO) P᎐
᎐
2
S units. For comparative purposes, theoretical calculations on
the models [Ru(η6-C H )Cl(κ2-P, N -H PCH P{᎐NP(᎐S)(OH) }-
᎐
᎐
᎐
᎐
6
6
2
2
2
H2)]ϩ and [Ru(η6-C H )Cl(κ2-P, S -H PCH P{᎐NP(᎐S)(OH) }-
6
6
2
2
2
H2)]ϩ are also discussed.
Results
Synthesis of iminophosphorane-phosphine ligands
Ph PCH P{᎐NP(᎐S)(OR) }Ph (R ؍ Et 1a, Ph 1b)
᎐
᎐
2
2
2
2
Thiophosphoryl azides (RO) P(᎐S)N (R = Et, Ph)13 react with
᎐
2
3
bis(diphenylphosphino)methane (dppm) (1 : 1 molar ratio), in
THF at Ϫ78 ЊC, to afford the novel (N-thiophosphoryl-imino-
phosphoranyl)(phosphino)methane ligands Ph PCH P{᎐NP-
᎐
2
2
(᎐S)(OR) }Ph (R = Et 1a, Ph 1b), which have been isolated as
᎐
2
2
air-stable white microcrystalline solids in 94 and 89% yield,
respectively (Scheme 1).
Scheme 1 Synthesis of iminophosphorane-phosphine ligands 1a,b.
Characterization of 1a,b was straightforward following their
analytical and spectroscopic data. Thus, the 31P–{1H} NMR
spectra show three well separated signals with equal relative
intensities (δP 1a: Ϫ27.18 (d, 2J(PP) = 62.7 Hz, Ph2P), 15.66 (dd,
2J(PP) = 62.7 and 32.1 Hz, Ph P᎐N) and 60.63 (d, 2J(PP) = 32.1
Scheme
2
Coordination of iminophosphorane-phosphine ligands
1a,b on a (η6-arene)-ruthenium() moiety.
᎐
2
2
Hz, (EtO) P᎐S); 1b: Ϫ27.58 (d, J(PP) = 63.4 Hz, Ph P), 17.15
᎐
2
2
An unequivocal proof of the monohapto coordination of
1a,b through the diphenylphosphino group in complexes 2a,b
and 5a,b is provided by their 31P–{1H} NMR spectra. Thus, the
(dd, 2J(PP) = 63.4 and 33.6 Hz, Ph P᎐N) and 52.93 (d, 2J(PP) =
᎐
2
33.6 Hz, (PhO) P᎐S)). The chemical shifts as well as the coup-
᎐
2
ling constants can be compared with those described in the
literature for related iminophosphorane compounds Ph2P-
2
Ph2P signal appears in the range δ 20.30–23.94 (d, J(PP) =
37.4–39.3 Hz), remarkably deshielded in relation to the free
ligands 1a,b (ca. ∆δ 48 ppm). In contrast, a slight shielding
is observed in the resonances corresponding to the imino-
phosphorane Ph2P᎐᎐N units (δ 11.58–13.53 (dd, J(PP) = 37.4–
39.3 and 23.4–27.9 Hz); ∆δ Ϫ4 ppm) and the thiophosphoryl
7
1
CH P(᎐NR)Ph and R P᎐NP(᎐S)(ORЈ) .14 In their H NMR
᎐
᎐
᎐
2
2
3
2
spectra the methylenic PCH2P hydrogens resonate as a doublet
(ca. 3.6 ppm) due to their coupling with the phosphorus atom
of the Ph P᎐N unit (ca. 2J(HP) = 14 Hz). As previously
2
᎐
2
reported for their phosphoryl counterparts Ph PCH P{᎐NP-
᎐
2
2
2
(RO)2P᎐᎐S groups (δ 51.69–59.68 (d, J(PP) = 23.4–27.9 Hz);
(᎐O)(OR) }Ph (R = Et, Ph),12 no coupling with the Ph2P phos-
᎐
1
∆δ Ϫ1 ppm). H and 13C–{1H} NMR spectra are also consist-
2
2
phorus nucleus, usually in the range 2J(HP) = 1–3 Hz for related
ent with the proposed formulations (details are given in the
ESI†). In particular, the methylenic PCH2P protons and carbons
appear at δ 3.87–4.43 (2a,b: one doublet of doublets signal,
2J(HP) = 9.4–9.8 Hz; 5a,b: two unresolved multiplets) and
Ph PCH P(᎐NR)Ph ligands,7 was observed. The methylenic
᎐
2
2
2
PCH2P carbon appears in the 13C–{1H} NMR as a doublet of
doublets signal (ca. 1J(CP) = 64 and 34 Hz; coupling with the PV
and PIII nuclei, respectively) at ca. 28 ppm.
20.30–25.02 (ddd, J(CP) = 71.6–75.5 (PV) and 15.1–18.9 (PIII)
1
3
Hz, J(CP) = 4.7–6.4 Hz) ppm, respectively. Noteworthy, the
Coordination of thiophosphorylated ligands Ph PCH P{᎐NP-
᎐
2
2
protons of the 2,7-dimethylocta-2,6-diene-1,8-diyl chain in the
ruthenium() complexes 5a,b give rise to only six resonances
and their carbon atoms to five in the NMR spectra, suggesting
that the two halves of the bis(allyl) ligand are in equivalent
environments, as expected for the formation of a simple
equatorial adduct with C2-symmetry.16
(᎐S)(OR) }Ph (R ؍ Et 1a, Ph 1b) to ruthenium(II) and
᎐
2
2
ruthenium(IV) fragments
(a) Synthesis of ꢀ1-P-complexes [Ru(ꢁ6-p-cymene)Cl2(ꢀ1-P-
Ph PCH P{᎐NP(᎐S)(OR) }Ph )] (R ؍ Et 2a, Ph 2b) and
᎐
᎐
2
2
2
2
[Ru(ꢁ3:ꢁ3-C H )Cl (ꢀ1-P-Ph PCH P{᎐NP(᎐S)(OR) }Ph )] (R
᎐
᎐
10 16
2
2
2
2
2
D a l t o n T r a n s . , 2 0 0 3 , 3 2 4 0 – 3 2 4 9
3241

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Fig. 1 ORTEP-type view of the structure of the cation [Ru(η3:η3-
C10H16)Cl(κ2-P, S -Ph2PCH2P{᎐NP(᎐S)(OEt)2}Ph2)]ϩ of 6a showing the
᎐
᎐
crystallographic labeling scheme. Hydrogen atoms are omitted for
clarity, and only the ipso-carbons of the phenyl rings of the Ph2P
groups are shown. Thermal ellipsoids are drawn at the 20% probability
level. Selected bond lengths (Å) and angles (Њ): Ru–C(1) = 2.242(9); Ru–
C(2) = 2.332(9); Ru–C(4) = 2.297(9); Ru–C* = 2.038(11); C(1)–C(2) =
1.422(13); C(2)–C(4) = 1.409(13); Ru–C(7) = 2.321(9); Ru–C(8) =
2.289(9); Ru–C(10) = 2.254(9); Ru–C** = 2.038(9); C(7)–C(8) =
1.390(14); C(8)–C(10) = 1.426(13); Ru–P(1) = 2.444(2); Ru–S(1) =
2.437(3); Ru–Cl(1) = 2.441(4); P(1)–C(27) = 1.857(9); C(27)–P(2) =
1.816(9); P(2)–N(1) = 1.591(7); N(1)–P(3) = 1.573(8); P(3)–O(1) =
1.576(7); P(3)–O(2) = 1.579(7); P(3)–S(1) = 1.995(4); C*–Ru–C** =
130.0(4); C*–Ru–S(1) = 87.0(3); C**–Ru–S(1) = 95.5(3); C*–Ru–Cl(1) =
87.8(3); C**–Ru–Cl(1) = 94.0(3); C*–Ru–P(1) = 114.8(4); C**–Ru–P(1)
= 115.0(3); S(1)–Ru–P(1) = 92.02(8); S(1)–Ru–Cl(1) = 170.39(8); P(1)–
Ru–Cl(1) = 82.84(8); Ru–P(1)–C(27) = 114.7(3); Ru–P(1)–C(15) =
113.4(3); Ru–P(1)–C(21) = 123.5(3); P(1)–C(27)–P(2) = 123.9(5); C(27)–
P(2)–N(1) = 114.4(4); C(27)–P(2)–C(28) = 104.1(4); C(27)–P(2)–C(34) =
112.3(4); P(2)–N(1)–P(3) = 130.3(5); N(1)–P(3)–O(1) = 107.9(4); N(1)–
P(3)–O(2) = 108.1(4); N(1)–P(3)–S(1) = 118.3(3); O(1)–P(3)–S(1) =
107.7(3); O(1)–P(3)–O(2) = 107.1(4); O(2)–P(3)–S(1) = 107.2(3); P(3)–
S(1)–Ru = 115.5(2). C* and C** = centroids of the allyl units (C(1),
C(2), C(4) and C(7), C(8), C(10), respectively).
Scheme
3
Coordination of iminophosphorane-phosphine ligands
1a,b on a bis(allyl)-ruthenium() moiety.
(b) Synthesis of ꢀ2-P,S-complexes [Ru(ꢁ6-p-cymene)-
Cl(ꢀ2-P,S-Ph PCH P{᎐NP(᎐S)(OR) }Ph )][SbF ] (R ؍ Et 3a,
᎐
᎐
2
2
2
2
6
Ph 3b) and [Ru(ꢁ3:ꢁ3-C H )Cl(ꢀ2-P,S-Ph PCH P{᎐NP(᎐S)-
᎐
᎐
10 16
2
2
(OR)2}Ph2)][SbF6] (R ؍ Et 6a, Ph 6b). Treatment of dichloro-
methane solutions of neutral complexes 2a,b and 5a,b with 1
equiv. of silver hexafluoroantimonate results in the formation
of the cationic derivatives [Ru(η6-p-cymene)Cl(κ2-P, S-Ph2-
PCH P{᎐NP(᎐S)(OR) }Ph )][SbF ] (R = Et 3a, Ph 3b; Scheme
᎐
᎐
2
2
2
6
2) and [Ru(η3:η3-C H )Cl(κ2-P, S -Ph PCH P{᎐NP(᎐S)(OR) }-
᎐
᎐
10 16
2
2
2
Ph2)][SbF6] (R = Et 6a, Ph 6b; Scheme 3), respectively, via
selective S-coordination of the free N-thiophosphoryl-imino-
phosphoranyl fragment (80–96% yield). As expected, these
complexes can be also prepared in similar yields from dimers
[{Ru(η6-p-cymene)(µ-Cl)Cl}2] and [{Ru(η3:η3-C10H16)(µ-Cl)-
Cl}2] by reaction with 2 equiv. of 1a,b and AgSbF6 in dichloro-
methane at room temperature (see Schemes 2 and 3).
distances in the ranges 2.242(9)–2.332(9) and 1.390(14)–
1.426(13) Å, respectively (see caption for Fig. 1). These values,
together with the internal allylic C–C–C angles (117.1(9)Њ and
116.5(9)Њ), compare well with those observed in other structures
containing the “Ru(η3:η3-C10H16)” unit.16 Concerning the imi-
nophosphorane-phosphine ligand backbone, the most remark-
able feature is that the lengths of the formal single and double
PN bonds were found to be very similar (1.573(8) Å and
1.591(7) Å, respectively). This apparent discrepancy, which
seems to be a usual trend in iminophosphorane compounds
R P᎐N–P(᎐X)(ORЈ) (X = O, S),7f,12,14,19 is attributed to the
Compounds 3a,b and 6a,b have been isolated as air-stable
orange microcrystalline solids. They have been characterized by
elemental analyses, conductance measurements, and IR and
NMR spectroscopy (see the ESI† for details). Moreover, the
formation of seven-membered chelate rings was unambigu-
ously confirmed by a X-ray diffraction study on the cation of
complex 6a.17 A drawing of the molecular structure is depicted
in Fig. 1; selected bond distances and angles are listed in the
caption. The geometry about the ruthenium() centre can be
described as a distorted trigonal bipyramid (TBPY) by con-
sidering the allyl groups as monodentate ligands bound to
ruthenium through their centres of mass (C* and C**; see
caption for Fig. 1). The iminophosphorane-phosphine ligand
1a is coordinated edge-on to the metal through the P atom of
the diphenylphosphino unit, which resides in an equatorial pos-
ition along with the allyl groups, and the thiophosphoryl S
atom, which is trans to the chloride ligand in an axial position.
The Ru–S bond length (2.437(3) Å) is typical for S-coordinated
thiophosphorus ligands.18 We note that an analogous arrange-
ment was shown by its phosphoryl counterpart [Ru(η3:η3-
C H )Cl(κ2-P, O-Ph PCH P{᎐NP(᎐O)(OEt) }Ph )]ϩ, in which
᎐
᎐
3
2
strong withdrawing effect of the thiophosphoryl group which
enhances the π delocalization of the lone pair of electrons on
nitrogen within the P–N–P unit. The P᎐S bond distance
᎐
(1.995(4) Å) is comparable to those found by Majoral and co-
workers in dendritic molecules containing P᎐N–P᎐S AuCl
᎐
᎐
moieties.20
NMR spectroscopic data of complexes 3a,b and 6a,b are
consistent with the κ2-P, S -coordination of the ligands and, in
particular, the chelate ring formation is clearly reflected in the
31P–{1H} NMR spectra. Thus, as a common trend, when the
spectra of 3a,b and 6a,b are compared to those of their neutral
precursors 2a,b and 5a,b slight shifts of the (RO) P᎐S and
᎐
2
Ph P᎐N resonances are observed, i.e. to highfield (ca. ∆δ Ϫ5
᎐
2
ppm) for the former (dd or d; δP = 46.38–54.92; 2J(PP) = 24.9–
3
28.3 Hz, J(PP) = 0–10.7 Hz) and to downfield (∆δ 0.5 to
᎐
᎐
10 16
2
2
2
2
the oxygen atom also occupies an axial position trans to the
chloride ligand.12 Both allyl groups of the octadienediyl frag-
ment are η3-bound to the ruthenium atom with Ru–C and C–C
4 ppm) for the latter (dd or d; δP = 13.12–15.52; 2J(PP) = 24.9–
28.3 and 0–3.8 Hz). The diphenylphosphino group resonances
are also affected by the ring closure but, surprisingly, while for
D a l t o n T r a n s . , 2 0 0 3 , 3 2 4 0 – 3 2 4 9
3242

View Article Online
6
2
᎐
ruthenium() complexes 3a,b they are ca. 3 ppm downfield
solvate
᎐
[Ru(η -p-cymene)(N᎐CMe)(κ -P, S-Ph PCH P{᎐NP-
᎐ ᎐
2 2
3
2
shifted (dd signal; ca. δP = 26; J(PP) = 4.9–10.7 Hz, J(PP) =
3.8 Hz), in their ruthenium() counterparts 6a,b they are high-
field shifted (∆δ Ϫ6 to Ϫ12 ppm; s signal; δP = 8.33–14.42).
Nevertheless, these chemical shifts, along with those of the
Ph P᎐N group, are in accord with the κ2-P, S -coordination of
(᎐S)(OEt) }Ph )][SbF ] 8 which has been isolated in 83% yield
2
2
6 2
(Scheme 4). Similarly, treatment of 4a with an excess of mono-
dentate phosphines (ca. 10 equiv.), in dichloromethane at room
temperature, generates the dicationic compounds [Ru(η6-p-
cymene)(PR )(κ2-P, S -Ph PCH P{᎐NP(᎐S)(OEt) }Ph )][SbF ]
(PR3 = PMe3 9, PMe2Ph 10, PMePh2 11) via selective Ru–P–N
chelate ring opening (80–96% yield; Scheme 4).
᎐
᎐
᎐
2
3
2
2
2
2
6 2
1a,b since we have recently reported that in κ2-P, N -complexes
[Ru(η6-p-cymene)Cl{κ2-P, N -Ph PCH P(᎐NR)Ph }]ϩ and [Ru-
᎐
2
2
2
(η3:η3-C H )Cl{κ2-P, N -Ph PCH P(᎐NR)Ph }]ϩ (R = H, aryl
᎐
10 16
2
2
2
group) the Ph P᎐N and Ph P phosphorus atoms resonate at
᎐
2
2
ca. 54 and 47 ppm, respectively.10,11f,21 In agreement with the
stereogenicity of the metal, the PCH2P protons are, in all the
cases, chemically inequivalent appearing as two unresolved
multiplets at δH 3.15–5.63. In contrast to 2a,b and 5a,b, the
PCH2P carbon resonates in the 13C–{1H} NMR spectra as a
doublet of doublets, due to exclusive coupling with the Ph P᎐N
᎐
2
(1J(CP) = 56.2–64.0 Hz) and Ph2P (1J(CP) = 7.6–16.9 Hz) units,
in the range 26.75–29.31 ppm. 1H and 13C–{1H} NMR spectra
of 6a,b indicate that the two halves of the 2,7-dimethylocta-2,6-
diene-1,8-diyl ligand are now in inequivalent environments
(i.e. ten different signals are observed by 13C–{1H} NMR
spectroscopy), as expected for the loss of the C2 symmetry.
(c) Synthesis of ꢀ3-P,N,S-complexes [Ru(ꢁ6-p-cymene)-
(ꢀ3-P,N,S-Ph PCH P{᎐NP(᎐S)(OR) }Ph )][SbF ] (R ؍ Et 4a,
᎐
᎐
2
2
2
2
6 2
Ph 4b) and [Ru(ꢁ3:ꢁ3-C H )(ꢀ3-P,N,S-Ph PCH P{᎐NP(᎐S)-
᎐
᎐
10 16
2
2
(OR)2}Ph2)][SbF6]2 (R ؍ Et 7a, Ph 7b). The reaction of neutral
complexes 2a,b and 5a,b with two equivalents of AgSbF6, in
dichloromethane at room temperature, generates the dicationic
Scheme 4 Reactivity of complex 4a towards neutral ligands.
derivatives
[Ru(η6-p-cymene)(κ3-P, N, S -Ph PCH P{᎐NP(᎐S)-
᎐ ᎐
2 2
Conductance measurements, as well as analytical and spectro-
scopic data, for 8–11 are in agreement with the proposed
structures (see the ESI†). In particular, the 31P–{1H} NMR spec-
(OR)2}Ph2)][SbF6]2 (R = Et 4a, Ph 4b; Scheme 2) and [Ru(η3:η3-
C H )(κ3-P, N, S-Ph PCH P{᎐NP(᎐S)(OR) }Ph )][SbF ] (R =
᎐
᎐
10 16
2
2
2
2
6 2
Et 7a, Ph 7b; Scheme 3), respectively, which have been isolated
as air-stable yellow (7a,b) or orange (4a,b) solids in 78–96%
yield. Alternatively, these compounds can be also obtained by
treatment of cationic complexes 3a,b and 6a,b with 1 equiv. of
AgSbF6 (see Schemes 2 and 3).
tra clearly reveal the presence of uncoordinated Ph P᎐N units
᎐
2
(δP 13.48–20.64; dd, 2J(PP) = 27.6–30.7 (PV) and 5.0–12.7 (PIII)
Hz).21 The spectra of complexes 9–11 also show the expected
resonances of the monodentate PR3 ligands which appear as a
doublet of doublets signal (0.78–4.39 ppm) due to coupling
with the coordinated Ph2P (2J(PP) = 41.5–49.7 Hz) and
(EtO) P᎐S (3J(PP) = 33.4–37.1 Hz) units. It is interesting to note
Conductance measurements in acetone (ΛM = 184–197 ΩϪ1
cm2 molϪ1) confirm that compounds 4a,b and 7a,b are 2 : 1
electrolytes (vs. 118–135 ΩϪ1 cm2 molϪ1 found for 3a,b and
6a,b). 31P–{1H} NMR spectra clearly indicate the coordination
of the iminophosphorane function to ruthenium showing char-
᎐
2
that the NMR spectra of complex 8 indicate that no reversible
process involving dissociation–recoordination of the aceto-
nitrile ligand occurs.
acteristic downfield resonances for the Ph P᎐N (δ 44.47–55.69;
Remarkably, all attempts to promote
a similar ring
᎐
2
P
dd, J(PP) = 21.9–32.6 (PV) and 9.8–28.3 (PIII) Hz) and Ph2P
(δP 30.90–43.38; dd, 2J(PP) = 9.8–28.3 Hz and 3J(PP) = 4.5–9.8
Hz) phosphorus nuclei,21 the (RO) P᎐S resonances appearing at
2
opening reaction with acetone have failed recovering the
starting complex 4a unchanged even under prolonged
reflux in this solvent. This result contrasts with the behaviour
previously observed for the phosphoryl compound [Ru-
(η6-p-cymene)(κ3-P, N, O -Ph PCH P{᎐NP(᎐O)(OEt) }Ph )]-
᎐
2
the expected chemical shifts (δP 46.46–56.95; dd, 2J(PP) = 21.9–
32.6 Hz and 3J(PP) = 4.5–9.8 Hz). 1H and 13C–{1H} NMR spec-
tra are also consistent with the proposed formulations (see the
ESI†). In particular, the PCH2P protons and carbon resonate at
3.98–5.17 ppm (two unresolved multiplets) and 25.10–34.26
ppm (dd (4a,b) or ddd (7a,b); 1J(CP) = 67.3–93.7 (PV) and 17.8–
19.3 (PIII) Hz, 3J(CP) = 0–8.3 Hz), respectively.
᎐
᎐
2
2
2
2
[SbF6]2 which reversibly generates the solvato complex
[Ru(η6-p-cymene)(κ1-O-Me CO)(κ2-P, O -Ph PCH P{᎐NP(᎐O)-
᎐
᎐
2
2
2
(OEt)2}Ph2)][SbF6]2 in acetone at room temperature.12
(b) Synthesis of ꢀ2-P,S-complexes [Ru(ꢁ6-p-cymene)-
X(ꢀ2-P,S-Ph PCH P{᎐NP(᎐S)(OEt) }Ph )][SbF ] (X ؍ Br 12, I
᎐
᎐
2
2
2
2
6
Reactivity of complex [Ru(ꢁ6-p-cymene)(ꢀ3-P,N,S–Ph2PCH2P-
13, N3 14). Complex 4a also reacts, via selective Ru–N bond
cleavage, with an excess (ca. 10 equiv.) of sodium salts NaX, in
methanol at room temperature, to afford the cationic deriv-
atives [Ru(η6-p-cymene)X(κ2-P, S -Ph PCH P{᎐NP(᎐S)(OEt) }-
{᎐NP(᎐S)(OEt) }Ph )][SbF ] 4a towards neutral and anionic
᎐
᎐
2
2
6 2
ligands
᎐
᎐
2
2
2
In order to compare the hemilabile properties of the thiophos-
Ph2)][SbF6] (X = Br 12, I 13, N3 14) which have been isolated
as air-stable orange microcrystalline solids in excellent yield
(89–96%; Scheme 5). We note that neutral complexes [Ru(η6-
p-cymene)X (κ1-P-Ph PCH P{᎐NP(᎐O)(OEt) }Ph )] (X = Cl,
phoryl ligands 1a,b in their κ3-P, N, S -coordination mode with
those of the κ3-P, N, O-coordinated phosphoryl counterparts
12
Ph PCH P{᎐NP(᎐O)(OR) }Ph
the reactivity of the di-
᎐
᎐
2
2
2
2
᎐
᎐
2
2
2
2
2
cationic
complex
[Ru(η6-p-cymene)(κ3-P, N, S -Ph2PCH2P-
Br, I, N3) were exclusively obtained when similar reactions were
conducted starting with [Ru(η6-p-cymene)(κ3-P, N, O-Ph2-
PCH P{᎐NP(᎐O)(OEt) }Ph )][SbF ] .12
{᎐NP(᎐S)(OEt) }Ph )][SbF ] 4a has been studied.
᎐
᎐
2
2
6 2
᎐
᎐
2
2
2
6 2
(a) Synthesis of ꢀ2-P,S-complexes [Ru(ꢁ6-p-cymene)(L)-
The novel complexes 12–14 have been characterized by ele-
mental analysis, conductance measurements, and IR and NMR
(1H, 31P–{1H} and 13C–{1H}) spectroscopy (see the ESI†). Since
their spectroscopic data are comparable to those observed for
3a, they will not be discussed further.
2
᎐
(ꢀ -P,S-Ph PCH P{᎐NP(᎐S)(OEt) }Ph )][SbF ] (L ؍ N᎐CMe
᎐
᎐
᎐
2
2
2
2
6 2
8, PMe3 9, PMe2Ph 10, PMePh2 11). We have found that Ru–N
bond cleavage easily takes place when complex 4a is dissolved
in acetonitrile at room temperature, affording the stable
D a l t o n T r a n s . , 2 0 0 3 , 3 2 4 0 – 3 2 4 9
3243

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Table 1 Absolute (hartrees) and relative (kcal molϪ1, parentheses)
energies for [Ru(η6-C6H6)Cl(κ2-P, N -H2PCH2P{᎐NP(᎐S)(OH)2}H2)]ϩ
A
᎐
᎐
and [Ru(η6-C6H6)Cl(κ2-P, S -H2PCH2P{᎐NP(᎐S)(OH)2}H2)]ϩ B modelsa
᎐
᎐
Model
B3LYP/DZV(d)
MP2/DZV(d)
A
B
Ϫ618.563254 (0.0)
Ϫ618.562109 (0.7)
Ϫ615.730363 (0.0)
Ϫ615.722347 (5.0)
a B3LYP/DZV(d)-optimized geometries.
Scheme 5 Reactivity of complex 4a towards anionic ligands.
Discussion
Novel trifunctional N-thiophosphoryl iminophosphorane-
phosphine ligands Ph PCH P{᎐NP(᎐S)(OR) }Ph (R = Et 1a,
᎐
᎐
2
2
2
2
Ph 1b) have been readily obtained by selective monooxidation
of dppm with thiophosphorylated azides (RO) P(᎐S)N (R =
᎐
2
3
Et, Ph), via a conventional Staudinger reaction (see Scheme 1).
The selectivity observed in these imination processes probably
stems from the proximity of the two Ph2P groups which hinders
the oxidation at the second phosphorus atom for steric
reasons.22 Nevertheless, in order to avoid the formation of the
corresponding bis(iminophosphorane) derivatives CH2[P-
{᎐NP(᎐S)(OR) }Ph ] ,23 a careful control of the temperature
Fig. 3 Computer plot of the B3LYP/DZV(d) optimized structures for
the model complexes [Ru(η6-C6H6)Cl(κ2-P, N -H2PCH2P{᎐NP(᎐S)-
᎐
᎐
᎐
᎐
2
2 2
(OH)2}H2)]ϩ
A
and [Ru(η6-C6H6)Cl(κ2-P, S -H2PCH2P{᎐NP(᎐S)-
᎐ ᎐
(Ϫ78 ЊC) is required as well as the use of a rigorous stoichio-
metric amount of the azides.
(OH)2}H2)]ϩ B. Selected bond lengths (Å) and angles (Њ) for model A:
Ru–P1 = 2.446; P1–C = 1.907; C–P2 = 1.878; P2–N = 1.714; N–Ru =
2.198; Ru–Cl = 2.497; average Ru–Carene = 2.276; Ru–P1–C = 107.3; P1–
C–P2 = 107.0; C–P2–N = 108.7; P2–N–Ru = 114.3; P1–Ru–N = 80.6; P1–
Ru–Cl = 80.5; N–Ru–Cl = 86.3. For model B: Ru–P1 = 2.439; P1–C =
1.899; C–P2 = 1.871; P2–N = 1.682; N–P3 = 1.655; P3–S = 2.182; S–Ru =
2.533; Ru–Cl = 2.485; average Ru–Carene = 2.278; Ru–P1–C = 119.0; P1–
C–P2 = 111.7; C–P2–N = 113.9; P2–N–P3 = 120.8; N–P3–S = 116.2; P3–S–
Ru = 110.2; P1–Ru–S = 96.3; P1–Ru–Cl = 84.3; S–Ru–Cl = 87.5.
Compounds 1a,b are versatile ligands for ruthenium() and
ruthenium() fragments derived from the readily available
chloro-bridged dimeric species [{Ru(η6-p-cymene)(µ-Cl)Cl}2]
and [{Ru(η3:η3-C10H16)(µ-Cl)Cl}2], respectively. As shown in
Schemes 2 and 3 they are able to adopt three different types of
coordination mode: (i) monodentate κ1-P in neutral complexes
2a,b and 5a,b, (ii) bidentate κ2-P, S -chelate in cationic com-
plexes 3a,b and 6a,b, and (iii) tridentate κ3-P, N, S -bis-chelate in
dicationic complexes 4a,b and 7a,b. These coordination features
reproduce those shown by the phosphoryl ligands Ph2PCH2P-
{᎐NP(᎐O)(OR) }Ph (R = Et, Ph; see Chart 1),12 with the
P1–Ru–N (80.6Њ), P1–Ru–Cl (80.5Њ), and N–Ru–Cl (86.3Њ) in
model A and P1–Ru–S (96.3Њ), P1–Ru–Cl (84.3Њ), and S–Ru–Cl
(87.5Њ) in model B, which are typical for pseudo-octahedral
three-legged piano-stool geometries, indicate similar strain
energies for both complexes.24 Thus, in the absence of marked
differences in strain energies between A and B, the results
obtained can be interpreted in terms of a very similar bond
energy of the Ru–N and Ru–S bonds. The preferred κ2-P, S - vs.
κ2-P, N -coordination of 1a,b experimentally observed should be
therefore attributed to the higher steric hindrances between the
thiophosphoryl group substituents and the η6-p-cymene or
η3:η3-octadienediyl ligands in the five-membered chelates. As
we have reported previously,12 this effect also governs the pref-
erence observed for the κ2-P, O - vs. κ2-P, N -coordination of the
related N-phosphoryl iminophosphorane-phosphine ligands in
their ruthenium complexes.
᎐
᎐
2
2
exception of the corresponding κ2-P, N -mode (see Fig. 2).
Fig. 2 Potential κ2-P, N-coordination of 1a,b.
In order to account for the preferred formation of the seven-
vs. five-membered chelate rings (κ2-P, S - vs. κ2-P, N -co-
ordination), also observed with their phosphoryl counterparts
(κ2-P, O- vs. κ2-P, N -coordination),12 the relative stability of
the models [Ru(η6-C H )Cl(κ2-P, N -H PCH P{᎐NP(᎐S)(OH) }-
However, the relatively small energetic difference found
between the five- (A) and seven-membered (B) chelate com-
plexes contrasts with that obtained in our calculations using the
phosphorylated ligand PH CH P{᎐NP(᎐O)(OH) }H (5.0 vs.
᎐
᎐
᎐
᎐
6
6
2
2
2
H )]ϩ A and [Ru(η6-C H )Cl(κ2-P, S -H PCH P{᎐NP(᎐S)(OH) }-
᎐
᎐
2
6
6
2
2
2
2
2
2
2
H2)]ϩ B has been theoretically studied following the method-
ology used for our previous calculations with the phosphoryl
derivatives.12
11.5 kcal molϪ1).12 This fact seems to indicate a higher strength
of the Ru—S bond vs. the Ru–O one in compounds [Ru(η6-
p-cymene)Cl(κ2-P, X-Ph PCH P{᎐NP(᎐X)(OR) }Ph )][SbF ]
᎐
᎐
2
2
2
2
6
The optimized structures for A and B with the B3LYP/
DZV(d) wave function are shown in Fig. 3, and their relevant
geometrical parameters, which compare well with those of the
previously optimized models [Ru(η6-C6H6)Cl(κ2-P, N -H2-
PCH P{᎐NP(᎐O)(OH) }H )]ϩ and [Ru(η6-C6H6)Cl(κ2-P, O -H2-
(X = O, S), in accord with the well-known stability of the Ru–S
bonds due to the soft character of the metal atom.
This theoretical prediction is also in accord with the experi-
mental reactivity of these complexes towards anionic ligands.
Thus, we have found that treatment of complex [Ru(η6-
p-cymene)Cl(κ2-P, S -Ph PCH P{᎐NP(᎐S)(OEt) }Ph )][SbF ] 3a
᎐
᎐
2
2
2
PCH P{᎐NP(᎐O)(OH) }H )]ϩ,12 are given in the caption. Both
᎐
᎐
᎐
᎐
2
2
2
2
2
2
2
6
structures were characterized as minima on the potential energy
surface, and their absolute and relative energies are listed in
Table 1.
with an excess of sodium salts NaX, in methanol at room tem-
perature, yields the cationic derivatives [Ru(η6-p-cymene)-
;X(κ2-P, S -Ph PCH P{᎐NP(᎐S)(OEt) }Ph )][SbF ] (X = Br 12, I
᎐
᎐
2
2
2
2
6
Both structures are almost isoenergetic at the B3LYP/
DZV(d)//B3LYP/DZV(d) level (see Table 1). Moreover, inclu-
sion of correlation results in a difference of only 5.0 kcal
molϪ1 in favour of the κ2-P, N -isomer A (MP2/DZV(d)//B3LYP/
DZV(d) level). Remarkably, the values of the interligand angles
13, N3 14) as the result of chloride metathesis (Scheme 6). In
contrast, we have previously reported that the analogous com-
plexes[Ru(η6-p-cymene)Cl(κ2-P, O -Ph PCH P{᎐NP(᎐O)(OR) }-
᎐
᎐
2
2
2
Ph2)][SbF6] (R = Et, Ph), under similar reaction conditions, do
not generate [Ru(η6-p-cymene)X(κ2-P, O -Ph PCH P{᎐NP(᎐O)-
᎐
᎐
2
2
D a l t o n T r a n s . , 2 0 0 3 , 3 2 4 0 – 3 2 4 9
3244

View Article Online
Table 2 Catalytic activity in transfer hydrogenation of cyclohexanone
of complexes 2–4a,b and 5–7a,ba
Entry
Catalyst
Yieldb (%)
TOF50 c/hϪ1
Ruthenium() complexes
1
2
3
4
5
6
2a
2b
3a
3b
4a
4b
54 (98)d
29 (97)e
21 (88)e
21 (75)e
9 (84)e
70
30
17
14
Scheme 6 Reactivity of complex 3a towards anionic ligands.
7 (47)e
–
(OR)2}Ph2)][SbF6], giving instead the neutral derivatives
[Ru(η6-p-cymene)X (κ1-P-Ph PCH P{᎐NP(᎐O)(OR) }Ph )]
᎐
᎐
2
2
2
2
2
Ruthenium() complexes
(X = Br, I, N3) through a chelate ring opening reaction.12 The
reluctance of 3a to undergo a cleavage of the Ru–S bond is also
assessed in the presence of neutral monodentate phosphines.
Thus, after prolonged treatment in dichloromethane at room
temperature, the complex 3a is recovered unchanged.25 All these
experimental data along with: (i) the lack of reversibility in the
formation of complex 8, (ii) the stability of 4a in acetone
and (iii) the selective formation of cationic complexes 12–14
from 4a (Scheme 5), allows one to establish that no hemilabile
properties can be associated with these thiophosphorylated
derivatives.
7
8
9
10
11
12
5a
5b
6a
6b
7a
7b
92 (>99)f
71 (98)d
1020
150
1600
230
1010
200
95 (>99)f
76 (98)d
94 (>99)f
72 (>99)e
a Conditions: reactions were carried out at 82 ЊC using 5 mmol of
i
cyclohexanone (0.2 M in PrOH). Ketone/catalyst/NaOH ratio: 250/1/
24. b Yield of cyclohexanol after 2 h. GC determined. c Turnover
frequencies ((mol product/mol catalyst)/time) were calculated at 50%
conversion. d Yield after 9 h in parentheses. e Yield after 24 h in
parentheses. f Yield after 4 h in parentheses.
Catalytic transfer hydrogenation of ketones
phoryl-ruthenium() complexes (TOF50: 14–70 vs. 10–50 hϪ1
;
Following our interest in ruthenium-catalyzed hydrogen trans-
fer reactions between alcohols and ketones,11f,12,26 the catalytic
activity in transfer hydrogenation of cyclohexanone by propan-
2-ol of ruthenium() and ruthenium() complexes 2–4a,b and
5–7a,b, respectively, has been explored (Scheme 7). Thus, in
see ref. 12 and Table 2), the ruthenium() derivatives 5–7a,b
are comparatively more active than their phosphoryl counter-
parts (TOF50: 150–1600 vs. 12–426 hϪ1; see ref. 12 and Table 2).
This is particularly remarkable in the case of the most
active ruthenium() complexes [Ru(η3:η3-C10H16)Cl(κ2-P, X -
Ph PCH P{᎐NP(᎐X)(OEt) }Ph )][SbF ] (TOF50: 426 hϪ1
a
typical experiment, the ruthenium catalyst precursor
(0.4 mol%) and NaOH (9.6 mol%) were added to a 0.2 M solu-
᎐
᎐
2
2
2
2
6
i
(X =O) vs. 1600 hϪ1 (X =S)). Providing that, as was established
above, the thiophosphoryl complexes do not show hemilabile
properties (in contrast to the phosphoryl ones)12 it can be con-
cluded that this property does not play a crucial role in the
formation of the active species. Although no detailed mech-
anistic studies have been performed, we have found that the
31P{1H}-NMR spectrum of the catalytic reaction mixture
derived from [Ru(η3:η3-C H )Cl(κ2-P, S -Ph PCH P{᎐NP(᎐S)-
tion of cyclohexanone in PrOH at 82 ЊC, the reaction being
monitored by gas chromatography. Selected results are shown
in Table 2.
᎐
᎐
10 16
2
2
(OEt)2}Ph2)][SbF6] 6a shows the clean formation of a novel
Scheme 7 Catalytic transfer hydrogenation of cyclohexanone by
species with resonances at δ 14.70 (d, 2J(PP) = 29.5 Hz, Ph P᎐
propan-2-ol.
᎐
P
2
N), 20.55 (s, Ph P) and 61.51 (d, 2J(PP) = 29.5 Hz, (EtO) P᎐S).
᎐
2
2
All the complexes tested, as their phosphoryl partners,12 have
proven to be active catalysts for the reduction of cyclohexanone
to cyclohexanol. We note that despite the large number of
transfer hydrogenation catalysts known,27 only a few of them
contains sulfur ligands and, to the best of our knowledge, no
transition-metal catalysts containing tridentate P, N, S -ligands
have been reported to date.28
Results of the catalytic activity collected in Table 2 allows a
comparison with those previously reported for the corre-
sponding phosphoryl-ruthenium complexes.12 In this regard,
the following similar trends have been observed in both studies:
(i) due to steric effects, the catalytic performances shown by the
catalysts containing the ligand 1a (R = Et) are much better than
those containing 1b (R = Ph) both in the Ru() and Ru() series
(see odd vs. even entries), (ii) the catalytic activities of the
ruthenium() complexes are in all cases higher than those of
their corresponding ruthenium() counterparts (see entries 1–6
vs. 7–12), and (iii) whilst the neutral κ1-P-complexes are the
most active in the Ru() series (entries 1 vs. 3 and 5, and 2 vs. 4
and 6), the cationic κ2-P, S -derivatives show the best perform-
ances in the Ru() series (entries 9 vs. 7 and 11, and 10 vs. 8 and
12). This seems to point out that there is no direct relationship
between the catalytic activity and the coordination mode of the
ligands.
These chemical shifts and coupling constants seem to indi-
cate the κ2-P, S-coordination of the ligand. Unfortunately, all
attempts to isolate this complex failed since after solvent
removal a complicated mixture of products is formed. Signifi-
cantly, no signals attributable to coordinated octadienediyl
1
units were observed in the H NMR spectra of this mixture,
suggesting that the active species in the catalytic cycle are
formed by the release of the bis(allyl) ligand.
In order to check the scope of the catalytic activity of the
most active complex 6a, the hydride transfer hydrogenation of
other dialkyl as well as aryl-alkyl ketones has been explored.
Results are summarized in Table 3.
Thus, complex 6a has been shown to be efficient in the reduc-
tion of dialkyl ketones (entries 1–4 in Table 3) although its
catalytic activity is significantly reduced when bulky substi-
tuents are present in the ketone (i.e. Me(Et)CO vs. Me(iPr)CO;
entry 3 vs. 4 in Table 3). Slow reductions have been also found
for aryl ketones, including acetophenone and its ortho-, meta-
and para-substituted derivatives (entries 5–10 in Table 3). It is
apparent that the introduction of electron-withdrawing groups
(Cl, Br) in the para or meta position of the aromatic ring allows
faster conversions (entries 7–9 vs. 5). In addition, a contrary
effect is observed with an electron-donor group (i.e. OMe; entry
6 vs. 5). Assuming that these catalytic transformations follow
the classical pathway in which the ketone coordinates to
hydride-ruthenium intermediates,27 the observed effects seem to
It is interesting to note that, in contrast to the similar
catalytic efficiencies found for both phosphoryl- and thiophos-
D a l t o n T r a n s . , 2 0 0 3 , 3 2 4 0 – 3 2 4 9
3245

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washed with diethyl ether (3 × 20 cm3) and vacuum-dried. 3a:
Yield: 0.423 g, 80%. 3b: Yield: 0.554 g, 96%.
Table 3 Catalytic transfer hydrogenation of ketones RRЈC᎐O by
᎐
complex 6aa
Method B. A suspension of [{Ru(η6-p-cymene)(µ-Cl)Cl}2]
(0.122 g, 0.2 mmol), the corresponding iminophosphorane-
Entry
R
RЈ
Yieldb (%)
TOF50 c/hϪ1
phosphine Ph PCH P{᎐NP(᎐S)(OR) }Ph 1a,b (0.43 mmol)
᎐
᎐
2
2
2
2
1
2
3
4
5
6
7
8
9
–(CH2)6–
–(CH2)5–
95 (>99)d
86 (98)e
58 (96)f
37 (76)f
39 (91)f
31 (73)f
66 (96)e
56 (98)f
64 (99)f
37 (42)f
1600
480
90
30
30
20
140
90
130
–
and AgSbF6 (0.137 g, 0.4 mmol) in dichloromethane (30 cm3)
was stirred, at room temperature and in the absence of light, for
1.5 h. Work-up as described in Method A allows the isolation of
3a,b in 83 (0.351 g) and 93% (0.429 g) yield, respectively.
Me
Me
Me
Me
Me
Me
Me
Me
Et
iPr
Ph
4-MeO-C6H4
4-Cl-C6H4
4-Br-C6H4
3-Br-C6H4
2-Br-C6H4
[Ru(ꢁ6-p-cymene)(ꢀ3-P,N,S-Ph PCH P{᎐NP(᎐S)(OR) }Ph )]-
᎐
᎐
2
2
2
2
[SbF6]2 (R ؍ Et 4a, Ph 4b). Method A. A solution of the corre-
sponding neutral complex [Ru(η6-p-cymene)Cl2(κ1-P-Ph2P-
10
CH P{᎐NP(᎐S)(OR) }Ph )] 2a,b (0.5 mmol) in dichloro-
᎐
᎐
2
2
2
a Conditions: reactions were carried out at 82 ЊC using 5 mmol
methane (50 cm3) was treated, at room temperature and in the
absence of light, with AgSbF6 (0.378 g, 1.1 mmol) for 1 h. After
the excess of AgSbF6 used and the AgCl formed were filtered
off (Kieselguhr), the solution was concentrated (ca. 2 cm3) and
diethyl ether (50 cm3) was then added yielding an orange micro-
crystalline solid which was washed with diethyl ether (3 ×
20 cm3) and vacuum-dried. 4a: Yield: 0.585 g, 93%. 4b: Yield:
0.650 g, 96%.
i
of ketone (0.2 M in PrOH). Ketone/catalyst/NaOH ratio: 250/1/24.
b Yield of the corresponding alcohol after 2 h. GC determined. c Turno-
ver frequencies ((mol product/mol catalyst)/time) were calculated at
50% conversion. d Yield after 4 h in parentheses. e Yield after 9 h in
parentheses. f Yield after 24 h in parentheses.
indicate that the hydride transfer from the metal to the co-
ordinated ketone is the turnover-limiting step (rather than the
ketone complexation) in the catalytic cycle.29
Method B. A solution of [Ru(η6-p-cymene)Cl(κ2-P, S -Ph2P-
CH P{᎐NP(᎐S)(OR) }Ph )][SbF ] 3a,b (0.5 mmol) in di-
᎐
᎐
2
2
2
6
chloromethane (50 cm3) was treated, at room temperature and
in the absence of light, with AgSbF6 (0.189 g, 0.55 mmol) for
1 h. Work-up as described in Method A allows the isolation of
4a,b in 92 (0.579 g) and 90% (0.609 g) yield, respectively.
Experimental
General comments
The manipulations were performed under an atmosphere of dry
nitrogen using vacuum-line and standard Schlenk techniques.
All reagents were obtained from commercial suppliers and used
without further purification with the exception of compounds
[Ru(ꢁ3:ꢁ3-C H )Cl (ꢀ1-P-Ph PCH P{᎐NP(᎐S)(OR) }Ph )]
(R ؍ Et 5a, Ph 5b). Complexes 5a,b, isolated as orange micro-
crystalline solids, were prepared as described for 2a,b starting
from [{Ru(η3:η3-C10H16)(µ-Cl)Cl}2] (0.246 g, 0.4 mmol) and the
᎐
᎐
10 16
2
2
2
2
2
[{Ru(η6-p-cymene)(µ-Cl)Cl}2],30
[{Ru(η3:η3-C10H16)(µ-Cl)-
corresponding iminophosphorane-phosphine Ph2PCH2P{᎐NP-
᎐
Cl}2]31 and (RO) P(᎐S)N (R = Et, Ph)13 which were prepared
᎐
2
3
(᎐S)(OR) }Ph 1a,b (0.85 mmol). 5a: Yield: 0.674 g, 98%. 5b:
᎐
2
2
by following the methods reported in the literature. Analytical
and spectroscopic data for all the compounds reported in this
paper have been provided as Electronic Supplementary Inform-
ation (ESI†).
Yield: 0.749 g, 98%.
[Ru(ꢁ3:ꢁ3-C H )Cl(ꢀ2-P,S-Ph PCH P{᎐NP(᎐S)(OR) }Ph )]-
᎐
᎐
10 16
2
2
2
2
[SbF6] (R ؍ Et 6a, Ph 6b). Complexes 6a,b, isolated as orange
microcrystalline solids, were prepared as described for 3a,b
starting either from [Ru(η3:η3-C10H16)Cl2(κ1-P-Ph2PCH2P-
Preparations
Ph PCH P{᎐NP(᎐S)(OR) }Ph (R ؍ Et 1a, Ph 1b). The cor-
{᎐NP(᎐S)(OR) }Ph )] 5a,b (0.5 mmol; Method A) or
᎐ ᎐
2 2
᎐
᎐
2
2
2
2
responding azide (RO) P(᎐S)N (5.2 mmol) was added at
[{Ru(η3:η3-C10H16)(µ-Cl)Cl}2] (0.123 g, 0.2 mmol; Method B).
6a: Yield (Method A): 0.509 g, 96%; Yield (Method B): 0.382 g,
90%. 6b: Yield (Method A): 0.520 g, 90%; Yield (Method B):
0.430 g, 93%.
᎐
2
3
Ϫ78 ЊC to a solution of bis(diphenylphosphino)methane (2 g,
5.2 mmol) in THF (80 cm3). The reaction mixture was slowly
warmed to room temperature and then evaporated to dryness
to give a colorless oil. A microcrystalline white solid was
obtained by slow diffusion of n-pentane into a saturated solu-
tion of the product in dichloromethane at room temperature.
1a: Yield: 2.69 g, 94%. 1b: Yield: 2.99 g, 89%.
[Ru(ꢁ3:ꢁ3-C H )(ꢀ3-P,N,S-Ph PCH P{᎐NP(᎐S)(OR) }Ph )]-
᎐
᎐
10 16
2
2
2
2
[SbF6]2 (R ؍ Et 7a, Ph 7b). Complexes 7a,b, isolated as yellow
microcrystalline solids, were prepared as described for 4a,b
starting either from [Ru(η3:η3-C10H16)Cl2(κ1-P-Ph2PCH2P-
{᎐NP(᎐S)(OR) }Ph )] 5a,b (0.5 mmol; Method A) or [Ru(η3:η3-
[Ru(ꢁ6-p-cymene)Cl (ꢀ1-P-Ph PCH P{᎐NP(᎐S)(OR) }Ph )]
᎐
᎐
᎐
᎐
2
2
2
2
2
2
2
(R ؍ Et 2a, Ph 2b). A solution of [{Ru(η6-p-cymene)(µ-Cl)Cl}2]
C H )Cl(κ2-P, S -Ph PCH P{᎐NP(᎐S)(OR) }Ph )][SbF ] 6a,b
᎐ ᎐
10 16 2 2 2 2 6
(0.245 g, 0.4 mmol) and the corresponding iminophosphorane-
(0.5 mmol; Method B). 7a: Yield (Method A): 0.510 g, 81%;
Yield (Method B): 0.491 g, 78%. 7b: Yield (Method A): 0.557 g,
82%; Yield (Method B): 0.542 g, 80%.
phosphine Ph PCH P{᎐NP(᎐S)(OR) }Ph 1a,b (0.85 mmol) in
᎐
᎐
2
2
2
2
dichloromethane (30 cm3) was stirred at room temperature for
1 h. The solution was then concentrated (ca. 2 cm3) and diethyl
ether (50 cm3) was added yielding an orange microcrystalline
solid which was washed with diethyl ether (3 × 10 cm3) and
vacuum-dried. 2a: Yield: 0.611 g, 89%. 2b: Yield: 0.687 g, 90%.
6
2
᎐
[Ru(ꢁ -p-cymene)(N᎐CMe)(ꢀ -P,S-Ph PCH P{᎐NP(᎐S)-
᎐
᎐
᎐
2
2
(OEt)2}Ph2)][SbF6]2 8. A solution of complex 4a (0.629 g,
0.5 mmol) in acetonitrile (30 cm3) was stirred at room temper-
ature for 1 h and then evaporated to dryness. The resulting
yellow oil was dissolved in 10 cm3 of dichloromethane. Addi-
tion of diethyl ether (50 cm3) afforded a microcrystalline solid
which was washed with diethyl ether (3 × 20 cm3) and vacuum-
dried. Yield: 0.539 g, 83%.
[Ru(ꢁ6-p-cymene)Cl(ꢀ2-P,S-Ph PCH P{᎐NP(᎐S)(OR) }Ph )]-
᎐
᎐
2
2
2
2
[SbF6] (R ؍ Et 3a, Ph 3b). Method A. A solution of the
corresponding neutral complex [Ru(η6-p-cymene)Cl2(κ1-P-
Ph PCH P{᎐NP(᎐S)(OR) }Ph )] 2a,b (0.5 mmol) in dichloro-
᎐
᎐
2
2
2
2
methane (50 cm3) was treated, at room temperature and in the
absence of light, with AgSbF6 (0.172 g, 0.5 mmol) for 1 h. After
the AgCl formed was filtered off (Kieselguhr), the solution was
concentrated (ca. 2 cm3) and diethyl ether (50 cm3) was then
added yielding an orange microcrystalline solid which was
[Ru(ꢁ6-p-cymene)(PR )(ꢀ2-P,S-Ph PCH P{᎐NP(᎐S)(OEt) }-
᎐
᎐
3
2
2
2
Ph2)][SbF6]2 (PR3 ؍ PMe3 9, PMe2Ph 10, PMePh2 11). A solu-
tion of complex 4a (0.629 g, 0.5 mmol) and the appropriate
phosphine (5 mmol) in dichloromethane (30 cm3) was stirred at
D a l t o n T r a n s . , 2 0 0 3 , 3 2 4 0 – 3 2 4 9
3246

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Table 4 Crystal data and structure refinement for 6a
room temperature for 5 (complex 9), 6 (complex 10) or 7 h
(complex 11) and then concentrated to ca. 5 cm3. Addition of
diethyl ether (40 cm3) afforded a yellow microcrystalline solid
which was washed with diethyl ether (3 × 20 cm3) and vacuum-
dried. 9: Yield: 0.640 g, 96%. 10: Yield: 0.558 g, 80%. 11: Yield:
0.634 g, 87%.
Empirical formula
Formula weight
Temperature/K
Crystal system
RuC46H64Cl5F4P3O2BNS
1153.08
120.0(2)
Monoclinic
P21/c
Space group
a/Å
b/Å
c/Å
α/Њ
12.1739(6)
23.8656(9)
21.1320(8)
90
[Ru(ꢁ6-p-cymene)X(ꢀ2-P,S-Ph PCH P{᎐NP(᎐S)(OEt) }Ph )]-
᎐
᎐
2
2
2
2
[SbF6] (X ؍ Br 12, I 13, N3 14). Method A. A solution of com-
plex 4a (0.629 g, 0.5 mmol) and the appropriate sodium salt
NaX (5 mmol) in methanol (50 cm3) was stirred at room tem-
perature for 1 h and then evaporated to dryness. The residue
was extracted with ca. 50 cm3 of dichloromethane, the sus-
pension filtered through Kieselguhr, and the resulting solution
concentrated to ca. 2 cm3. Addition of diethyl ether (40 cm3)
afforded an orange microcrystalline solid which was washed
with diethyl ether (3 × 20 cm3) and vacuum-dried. 12: Yield:
0.491 g, 89%. 13: Yield: 0.552 g, 96%. 14: Yield: 0.479 g, 90%.
Method B. A solution of complex 3a (0.529 g, 0.5 mmol)
and the appropriate sodium salt NaX (5 mmol) in methanol
(50 cm3) was stirred at room temperature overnight and then
evaporated to dryness. Work-up as described in Method A
allows the isolation of compounds 12–14 in 85 (0.468 g), 87
(0.501 g) and 80% (0.426 g) yield, respectively.
β/Њ
125.00(9)
90
5029(6)
4
1.523
6.705
γ/Њ
Volume/Å3
Z
Calculated density/g cmϪ3
Absorption coefficient/mmϪ1
F(000)
2376
Reflections collected/unique
Goodness-of-fit on F 2
Final R indices [I > 2σ(I )]a
R indices (all data)
Largest diff. peak and hole/e ÅϪ3
66067/9349 [R(int) = 0.059]
1.090
R1 = 0.0708, wR2 = 0.2102
R1 = 0.0863, wR2 = 0.2525
2.040 and Ϫ1.315
a R1 = Σ(|Fo| Ϫ |Fc|)/Σ|Fo|; wR2 = {Σ[w(Fo2 Ϫ Fc2)2]/Σ[w(Fo )2]} .
2
½
See http://www.rsc.org/suppdata/dt/b3/b305520e/ for crystal-
lographic data in CIF or other electronic format.
General procedure for catalytic transfer hydrogenation of
ketones
Computational details
All calculations were carried out with the Gaussian98 program
package.40 The molecular geometries were optimized, without
any molecular symmetry constraint, using SchlegelЈs analytical
gradient procedure41 at the B3-LYP variant of density func-
tional theory42 with the standard split-valence 6-31G(d) basis
set for C, N, O, and H,43 and the pseudo-relativistic effective
core potential (ECP) by Hay and Wadt for Ru, P, S, and Cl.44
This basis set was referred to as DZV(d). The optimized struc-
tures were characterized as minima (representing equilibrium
structures) by analytic frequency calculations. Single-point
calculations on the DFT geometries were performed with the
incorporation of correlation energy using Møller–Plesset
perturbation theory with second-order corrections (MP2).45
Under an inert atmosphere the ketone (5 mmol), the ruthenium
catalyst precursor (0.02 mmol, 0.4 mol%), and propan-2-ol
(20 cm3) were introduced into a Schlenk tube fitted with a con-
denser and heated at 82 ЊC for 15 min. Then NaOH was added
(5 cm3 of a 0.096 M solution in propan-2-ol, 9.6 mol%) and the
reaction monitored by gas chromatography. The corresponding
alcohol and acetone were the only products detected in all cases.
X-Ray crystal structure of [Ru(ꢁ3:ꢁ3-C10H16)Cl(ꢀ2-P,S-Ph2-
PCH P{᎐NP(᎐S)(OEt) }Ph )][BF ]ؒ2CH Cl ؒC H12 (the cation
᎐
᎐
2
2
2
4
2
2
5
of 6a)
Crystals suitable for X-ray diffraction analysis were obtained by
slow diffusion of n-pentane into a saturated solution of the
complex in dichloromethane. Data collection, crystal, and
refinement parameters are collected in Table 4. Diffraction data
were recorded on a Nonius Kappa CCD single crystal diffract-
ometer using Cu-Kα radiation (λ = 1.54184 Å). The crystal–
detector distance was fixed at 29 mm and a total of 1130 frames
were collected using the oscillation method, with 2Њ oscillation
and 25 s exposure time per frame. Data collection strategy was
calculated with the program Collect.32 Data reduction and cell
refinement were performed using the programs HKL Denzo
and Scalepack.33 Unit cell dimensions were determined from
8421 reflections. All data completeness was 96.2%.
Acknowledgements
This work was supported by the Ministerio de Ciencia y
Tecnología (MCyT) of Spain (Projects BQU2000-0219,
BQU2000-0227, BQU2001-1625 and CAJAL-01-03) and the
Gobierno del Principado de Asturias (Project PR-01-GE-4).
We thank Dr Marta Martín (Universidad de Zaragoza) for EA
measurements. S. E. G.-G. also thanks the MCyT for the award
of a Ph.D. grant.
References and notes
The structure was solved by Patterson methods using the
program DIRDIF.34 An empirical absorption correction was
applied using XABS2.35 Full-matrix least-squares refinement
on F 2 was carried out with SHELXL-97.36 All non-H atoms
were anisotropically refined with the exception of the altern-
ative partially occupied positions C42 and C42A atoms of the
disordered n-pentane solvent molecule which were isotropically
refined. The H atoms were geometrically placed and their co-
ordinates were refined riding on their parent atoms. The maxi-
mum shift-to-e.s.d. ratio in the last full-matrix least-squares
cycle was 0.000. Atomic scattering factors were taken from the
International Tables for X-ray Crystallography.37 Geometrical
calculations were made with PARST.38 The crystallographic
plots were made with PLATON.39 All calculations were per-
formed at the Scientific Computer Centre of the University of
Oviedo using VAX and DEC-ALPHA computers.
1 H. Staudinger and J. Meyer, Helv. Chim. Acta, 1919, 2, 635.
2 For reviews see: (a) Y. G. Gololobov, I. N. Zhamurova and L. F.
Kasukhin, Tetrahedron, 1981, 37, 437; (b) Y. G. Gololobov and
L. F. Kasukhin, Tetrahedron, 1992, 48, 1353; (c) A. W. Johnson, in
Ylides and Imines of Phosphorus, Wiley, New York, 1993, p. 403.
3 See for example: (a) E. W. Abel and S. A. Mucklejohn, Phosphorus,
Sulfur Relat. Elem., 1981, 9, 235 and references therein;
(b) J. Vicente, A. Arcas, D. Bautista and M. C. Ramírez de
Arellano, Organometallics, 1998, 17, 4544 and references therein;
(c) A. Steiner, S. Zacchini and P. I. Richards, Coord. Chem. Rev.,
2002, 227, 193 and references therein.
4 Iminophosphorane derivatives can also act as four electron donors,
i.e. in [Mo2(CO)6(HN᎐PPh3)3] each P᎐N ligand bridges the two Mo
᎐
᎐
atoms via N: J. S. Miller, M. O. Visscher and K. G. Caulton,
Inorg. Chem., 1974, 13, 1632.
5 The coordination chemistry of the related phosphoraneiminato
derivatives (R3P᎐NϪ) is also well documented. For reviews see:
᎐
(a) K. Dehnicke and J. Strähle, Polyhedron, 1989, 8, 707;
(b) K. Dehnicke and F. Weller, Coord. Chem. Rev., 1997, 158, 103;
CCDC reference number 210707.
D a l t o n T r a n s . , 2 0 0 3 , 3 2 4 0 – 3 2 4 9
3247

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(c) K. Dehnicke, M. Krieger and W. Massa, Coord. Chem. Rev.,
1999, 182, 19; (d ) H. J. Cristau, M. Taillefer and N. Rahier,
J. Organomet. Chem., 2002, 646, 94.
6 See for example: (a) M. Fukui, K. Itoh and Y. Ishii, Bull. Chem. Soc.
Jpn., 1975, 48, 2044; (b) E. W. Abel and S. A. Mucklejohn,
Inorg. Chim. Acta, 1979, 37, 107; (c) H. F. Sleiman, S. Mercer and
L. McElwee-White, J. Am. Chem. Soc., 1989, 111, 8007; (d ) P.
Imhoff, C. J. Elsevier and C. H. Stam, Inorg. Chim. Acta, 1990, 175,
209.
Heteroatom Chem., 2002, 13, 474; (h) A. M. Caminade, V. Maraval,
R. Laurent and J. P. Majoral, Curr. Org. Chem., 2002, 6, 739.
15 For reviews on the chemistry of [{Ru(η6-arene)(µ-Cl)Cl}2] dimers
see: (a) H. Le Bozec, D. Touchard and P. H. Dixneuf, Adv.
Organomet. Chem., 1989, 29, 163; (b) M. A. Bennett, in
Comprehensive Organometallic Chemistry II, ed. E. W. Abel, F. G. A.
Stone, and G. Wilkinson, Pergamon Press, Oxford, 1995, vol. 7,
p. 549; (c) M. A. Bennett, Coord. Chem. Rev., 1997, 166, 225;
(d ) F. C. Pigge and J. J. Coniglio, Curr. Org. Chem., 2001, 5, 757.
16 For recent references dealing with the chemistry of the bis(allyl)-
ruthenium() dimer [{Ru(η3:η3-C10H16)(µ-Cl)Cl}2] see: (a) S. M.
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17 Only the tetrafluoroborate salt of 6a (Found: C, 51.37; H, 5.29;
N, 1.62. RuC39H48F4P3O2BClNS requires C, 51.41; H, 5.31; N,
1.54%) gave crystals suitable for X-ray diffraction. This compound
was obtained using AgBF4 instead of AgSbF6.
7 See for example: (a) V. A. Gilyarov, V. Y. Kovtum and M. I.
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᎐
ligands see: (a) K. V. Katti and R. G. Cavell, Comments
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23 These compounds are properly prepared using two equivalents
of (RO)2P(᎐S)N3. Details on their synthesis and coordination
᎐
11 Hydrogenation of olefins (Rh, and Ir complexes): (a) D. J. Law and
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reaction between tricoordinated phosphorus atoms and function-
alised thiophosphoryl azides to design a large variety of dendrimers
chemistry will be the subject of a forthcoming article.
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abnormal interligand angles about the metal, which results in a
higher energy than would be the case in the absence of angle
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25 We note that complexes [Ru(η6-p-cymene)Cl(κ2-P, O -Ph2PCH2P{᎐
᎐
NP(᎐O)(OR)2}Ph2)][SbF6] (R
=
Et, Ph) readily react with
᎐
phosphines, in dichloromethane at room temperature, to afford the
corresponding adducts [Ru(η6-p-cymene)Cl(PR3)(κ1-P-Ph2PCH2P-
{᎐NP(᎐O)(OR)2}Ph2)][SbF6] (PR3
= PMe3, PMe2Ph, PMePh2,
᎐
᎐
PPh3): V. Cadierno, J. García-Álvarez and J. Gimeno, unpublished
results.
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᎐
᎐
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