Cyclometallated ruthenium complexes with P-stereogenic monophosphines containing a polycyclic aromatic substituent

Article abstract of DOI:10.1016/j.jorganchem.2019.05.015

Reactions of optically pure P-stereogenic ortho-tolyl substituted phosphines with [RuCl₂(p-cymene)]₂ afforded the corresponding κP-coordinated ruthenium(II) dichlorides (C1′, C2’) even in the presence of sodium acetate. In contrast,

Full text of DOI:10.1016/j.jorganchem.2019.05.015

Accepted Manuscript
Cyclometallated ruthenium complexes with P-stereogenic monophosphines
containing a polycyclic aromatic substituent
Arnald Grabulosa, Jaume Granell, Mercè Font-Bardia
PII:
S0022-328X(19)30204-9
DOI:
https://doi.org/10.1016/j.jorganchem.2019.05.015
JOM 20797
Reference:
To appear in: Journal of Organometallic Chemistry
Received Date: 8 April 2019
Revised Date: 15 May 2019
Accepted Date: 16 May 2019
Please cite this article as: A. Grabulosa, J. Granell, Mercè. Font-Bardia, Cyclometallated ruthenium
complexes with P-stereogenic monophosphines containing a polycyclic aromatic substituent, Journal of
Organometallic Chemistry (2019), doi: https://doi.org/10.1016/j.jorganchem.2019.05.015.
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ACCEPTED MANUSCRIPT
Cyclometallated ruthenium complexes with P-stereogenic
monophosphines containing a polycyclic aromatic substituent
a
a
b
Arnald Grabulosa, * Jaume Granell, Mercè Font-Bardia
a
Departament de Química Inorgànica i Orgànica, Secció de Química
Inorgànica, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-
1
1, 08028 Barcelona, Spain.
b
Unitat de Difracció de RX. Centres Científics i Tecnològics de la Universitat de
Barcelona (CCiTUB), Solé i Sabarís 1-3. 08028 Barcelona, Spain.
Abstract:
Reactions of optically pure P-stereogenic ortho-tolyl substituted phosphines with
[
RuCl (p-cymene)] afforded the corresponding κP-coordinated ruthenium(II)
2 2
dichlorides (C1’, C2’) even in the presence of sodium acetate. In contrast, the
2
ruthenium cyclometallated (
κ
-C,P) complexes (C3-C9) were obtained with
phosphines containing a polycyclic aromatic substituent (L3-L9), namely 1-
naphthyl, 9-phenanthryl or 1-pyrenyl. Some diastereoselectivity in the
cyclometallation process has been observed for the most bulky ligands. The
new compounds have been used as catalytic precursors in the reduction of
acetophenone to 1-phenylethanol by transfer hydrogenation.
Keywords: ruthenium, cyclometallated complexes, P-stereogenic phosphines,
asymmetric catalysis, reduction of ketones.
1
Introduction
The cyclometallation reaction is a transition metal C-H activation to form a
metallacyle containing a new metal-carbon σ-bond. This reaction can be split
into two main processes: the coordination of the heteroatom of the ligand to the
metal and, in a second step, activation of one of the C-H bonds of the ligand [1].
Cycloruthenation is an extremely versatile process and shows a broad scope
[
2], and cyclometallated ruthenium compounds have been used as catalysts in
different reactions including reduction of ketones and aldehydes [3], olefin
metathesis [4], C–C bond formation reaction [5], hydrogenation [6], and ortho-

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deuteration [7]. In addition to this, some cycloruthenated derivatives have been
shown to display interesting antitumour activities [8] and also promising
photophysical and electrochemical properties [9]. In recent years, the ruthenium
catalyzed ortho- or even meta-C−H bond functionalizations have become a
thriving research area [10].
Despite the long history of P-stereogenic ligands, they are relatively rare in the
literature because of their cumbersome synthesis [11]. The last two decades,
however, have witnessed a renaissance in the field with the appearance of new
methods amenable for the synthesis of such compounds [12].
Our group has worked with several types of chiral phosphines and with the
corresponding palladium and ruthenium complexes that have been used in
catalytic hydrovinylation (Pd) [13], allylic substitution (Pd) [13d,14],
cyclopropanation (Ru) [15] and transfer hydrogenation (Ru) [13d,15,16]
reactions.
Recently, a paper of Zhu and coworkers described the synthesis, structure,
reactivity and catalytic activity of cyclometallated ruthenium complexes with
phosphines containing the 1-naphthyl or the 2-tolyl groups [17]. They carried
out the cyclometallation reaction under very mild conditions in the presence of
sodium acetate forming neutral, Ru-stereogenic complexes that were obtained
as racemic mixtures since the phosphines used were achiral.
The aim of the present paper is to present the results obtained using Zhu’s
method to cyclometallate chiral optically pure P-sterereogenic phosphines (L1-
L9) developed previously in the group containing potentially cyclometallating
groups (2-tolyl, 1-naphthyl, 9-phenanthryl and 1-pyrenyl) in a process that
allows the synthesis of non-racemic Ru-stereogenic derivatives.

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2
Results and discussion
.1 Synthesis and characterisation of coordination compounds C1’ and C2’
2
The P-stereogenic ligands (L1-L9) shown in Chart 1 were prepared via
phosphine-boranes following the Jugé-Stephan methodology as we have
previously reported for ligands L3-L9 [13a,b 14, 16]. We here described the
synthesis of phosphine L1 by deprotection of the known phosphine-borane
L1·BH [18]. Phosphine L2 was obtained in low optical purity a long time ago
3
[
19] and in racemic form very recently [20]. We here report its first
enantioselective synthesis via its previously not reported borane adduct,
L2·BH3.
Chart 1, P-stereogenic phosphines
P-stereogenic phosphines L1 and L2 could afford a five-membered
3
cyclometallated derivative by activation of the C(sp )-H bond of the ortho-tolyl
fragment. The cyclorutenation of this fragment have been described in the
sterically demanding diisopropyl-(ortho-methylphenyl)phosphine, when this
phosphine is treated with the organometallic precursor [RuCl (p-cymene)] and
2
2
sodium acetate [17]. The importance of the ortho-C-H bond deprotonation by
carbonate [21] or carboxylate [22], as a proton shuttle to form a cyclometallated
ruthenium(II) complexes has been recognised while some DFT calculations
have shown that the C-H activation step involves a simultaneous metallation of
the C-H bond and intramolecular deprotonation by acetate [23]. The beneficial
effect of the bulkiness of phosphines in the cyclometallation process due to
entropic factors has also been known for quite a long time [24].
With the idea of obtaining cyclometallated complexes C1 and C2, the
organometallic precursor [RuCl (p-cymene)] was reacted with slightly more
2
2
than 2 equivalents of the ligand L1 or L2 (bearing the ortho-tolyl group), and
sodium acetate in methanol (Scheme 1). The excess of ligand ensures that no

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ruthenium precursor, which would be very difficult to separate from C1 and C2,
remained after the reaction.
Scheme 1, synthesis of coordination compounds C1’ and C2’
Despite many efforts at different sets of conditions, only the non-cyclometallated
1
dichlorocomplexes C1’ and C2’ were obtained, which were characterised by H,
31
1
13
1
31
1
P-{ H}, C-{ H} NMR spectra and high-resolution mass spectroscopy. P-{ H}
NMR spectroscopy is a very useful tool to determine if the cyclometallated
compound has been formed [25]. Only a signal at 20 ppm and 40 ppm was
31
1
observed in P-{ H} NMR spectra for the reactions with L1 and L2 respectively.
These chemical shifts are too low to correspond to the expected
cyclometallated complexes C1 and C2 and show that dichlorocomplexes C1’,
and C2’ were formed [13d,15, 17] instead (Scheme 1).
Suitable crystals of C1’ and C2’ were obtained from a dichloromethane-hexane
solution at 4 ºC and were analyzed by X-ray diffraction (see figure 1).
Figure 1. Left: Ball and stick representation of C1' showing the labelling scheme; hydrogen
atoms have been omitted for clarity. Selected bond lengths [Å] and angles [°]: Ru(1)–P(1)
2
.3640(6), Ru(1)–Cl(1) 2.4103(6), Ru(1)–Cl(2) 2.4180(6), P(1)–C(1) 1.829(2); Ru(1)–P(1)–C(1)
11.13(7); P(1)-C(14) 1.820(2).
1
Right: Ball and stick representation of C2' showing the labelling scheme; hydrogen atoms have
been omitted for clarity. Selected bond lengths [Å] and angles [°]: Ru(1)–P(1) 2.3844(17),

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Ru(1)–Cl(1) 2.4287(15), Ru(1)–Cl(2) 2.4081(15), P(1)–C(11) 1.846(6); Ru(1)–P(1)–C(11)
09.27(19).P(1)-C(24) 1.870(6).
1
Both complexes form crystals that contain individual molecules separated by
Van der Waal contacts. The molecules contain a pseudotetrahedral ruthenium
6
centre coordinated to two chloride atoms, the phosphorus atom and the η -p-
cymene ring in the classical three-legged piano stool geometry, as commonly
6
found for complexes of the type [Ru(η -arene)Cl (monophosphine)] [13d,
2
1
5,17]. The phosphorus atom of the free phosphine would have the absolute
configuration S in both molecules, according to the Cahn-Ingold-Prelog
nomenclature system, as expected from the stereochemistry of the Jugé-
Stephan method and the enantiomer of ephedrine used [26]. The distances and
angles of C1’ and C2’ are very similar and in the range for similar complexes.
2
.2 Synthesis and characterisation of cyclometallated compounds C3-C5
After the unsuccessful preparation of C1 and C2, containing the cyclometallated
ortho-tolyl group, our attention was shifted towards the synthesis of complexes
C3-C5, containing the 1-naphthyl group. It has to be noted that the non-
cyclometallated dichlorocomplexes C3’-C5’ have been reported in previous
studies of our group [15]. The cyclometallation of these phosphines seems to
be easier than the metallation of L1 or L2 since L3-L5 are more sterically
demanding and because the metallacycle, in this case, would be formed by
2
3
activation of a C(sp )-H bond, an easier process than the activation of a C(sp )-
H bond of an ortho-methyl group.
The organometallic precursor [RuCl (p-cymene)] was reacted with slightly
2
2
more than 2 equivalents of the ligands L3-L5 and with sodium acetate in
31
1
methanol (Scheme 2). The signals observed in the P-{ H} NMR spectra of the
reaction mixtures (peaks at around 55, 75 and 160 ppm for the reactions with
L1, L2 and L3 respectively) were strongly deshielded in relation to the signals of
the corresponding previously reported dichlorocomplexes C3’-C5' (14.5, 30.3
and 166.6 ppm, respectively), pointing out that the cyclometallation reaction had
taken place [15,25].
Complexes C3-C5 were indeed obtained pure as brown solids in around 15%
yield, after purification by column chromatography. The low yields are probably
due to partial decomposition of the complexes during the purification step since
the analysis at short reaction times indicates that no other major species were

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present. NMR spectra and high-resolution mass spectroscopy of the complexes
confirmed that the cyclometallation had taken place.
Scheme 2, cyclometallation of L3-L5
31
1
The P-{ H} NMR spectrum consisted in two singlets in the case of C3' and C5'
because of the formation of two diastereomers with different absolute
configuration at the ruthenium atom. The diastereomeric ratios are 1:2.4 and
1
:1.6 for C3 and C5 respectively. Interestingly, for complex C4, bearing the
bulkiest phosphine L4, only one singlet was observed, indicating that the
cyclometallation reaction had taken place diastereoselectively.
2
.3 Synthesis and characterisation of cyclometallated compounds C6-C9
We subsequently explored the cyclometallation of phosphines L6-L9,
containing a 9-phenanthryl or 1-pyrenyl groups, which could afford a five-
2
membered metallacycle by activation of a C(sp )-H bond (Scheme 3).
The reactions were performed in the same conditions used for L3-L6 (see
31
1
before). P-{ H} NMR spectra showed two peaks at low fields with respect of
dichlorocomplexes, after two hours of reaction, suggesting that the
cyclometallations had taken place for all the phosphines. It should be noted that
there is no precedent of Ru-cyclometallations with phosphines bearing those
groups.
Scheme 3, cyclometallation of L6-L9

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The products were purified by column chromatography. The yields were very
low (<8%), except for the C6, which was surprisingly obtained in 71% yield. The
low yields are due, as previously mentioned, to decomposition during
purification. It should also be noted that cyclometallated complexes with the
phosphinites (C7 and C9) were especially prone to decomposition and for this
reason they could not be fully characterised or used in catalysis. Unfortunately it
was not possible to study the complexes with the isopropyl phosphines with
these rings since Jugé-Stephan method does not allow to obtain the
corresponding ligands due to steric problems [13a].
All of the most significant peaks discussed in the previous complexes appear
1
duplicated at the H-NMR spectra (Figure 2), due to the formation of two
diastereomers. It is remarkable the high field shift of one of the signals (δ = 4.13
ppm) which suggest a proximity between this proton and the phenyl moiety. In
31
1
the P-{ H}-NMR spectra the two expected peaks appeared, corresponding to
the two diastereomeric species. The isomeric ratios were 1:3.2, 1:2.3, 1:2.6 and
1
:2.8 for complexes C6-C9 respectively.
6
Figure 2: NMR aromatic proton signals of η -C H fragment (δ = 6.4-3.8) of C6 and singlet at δ =
6
4
5.30 corresponding to dichloromethane.
From these results, it can be concluded that polycylic rings of the type 1-
naphtyl, 9-phenantryl and 1-pyrenyl are adequate to form cyclometallated
ruthenium complexes.
We were able to grow crystals suitable for X-ray measurements of C6, whose
molecular structure is shown in Figure 3. The structure confirms that the
2
cyclometallation reaction had taken place by a C(sp )-H activation of the 9-

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phenanthryl substituent of the phosphine. The molecules of the complex also
exhibit the three-legged piano stool geometry, being the ruthenium atom
coordinated to chloride, phosphorus and to the C11 of the 9-phenanthryl group
atoms, forming a five membered metallacycle. Remarkably, the Ru-P bond
distance [2.2825(9) Å] is much shorter than in C1' and C2' [2.3640(6) and
2
.3844(17) Å respectively] suggesting that the cyclometallation probably
contributes to release the tension of the molecular structure. A very short Ru(1)-
C(11) bond length [2.095(3)Å] is also present. This structure is very similar to
others recently described with 1-naphthylphosphines, demonstrating that
phosphines with fused aromatic polycyclic substituents are particularly prone to
cyclometallation [17].
Figure 3 Ball and stick representation of C6 showing the labelling scheme;
hydrogen atoms have been omitted for clarity. Selected bond lengths [Å] and angles [°]:
Ru(1)–P(1) 2.2825(9), Ru(1)–Cl(1) 2.4197(8),
Ru(1)–C(11) 2.095(3), P(1)–C(23) 1.805(3), C(23)–C(24) 1.437(5),
C(24)–C(11)1.432(5); P(1)–Ru(1)–Cl(1) 87.82(3), P(1)–Ru(1)–C(11)
80.42(10), C(11)–Ru(1)–Cl(1) 85.92(9), Ru(1)–P(1)–C(23) 105.26 (11).
The free phosphine ligand has S absolute configuration, as expected and,
remarkably, only one diastereomer of the complex is present in the crystal, with
R absolute configuration at the ruthenium atom. Therefore, the crystal
exclusively contains the (R ,R )-C6 isomer of the complex (the descriptor of
Ru
P
the absolute configuration of the phosphorus atom changes due to coordination
with respect to the free ligand), despite the fact that (S ,R )-C6 is also present
Ru
P
in solution according to NMR. This could be due to the higher insolubility of the
RRu diastereomer, or that the selected crystal contained this isomer while others

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contain the SRu or finally, although unlikely, it can not be excluded that the two
diastereomers are in equilibrium and that there is a dynamic resolution process
producing only the (R ,R )-C6 in the solid state. It has to be pointed out that
Ru
P
the crystal was very difficult to obtain due to the instability and low crystallinity of
C6 and for this reason the analysed crystal could not be recovered and
redissolved at low temperature to study if the diastereomeric mixture was
formed again or only one diastereomer was present in solution.
2
.4 Ruthenium-catalysed Asymmetric Transfer Hydrogenation
The ruthenium complexes described in the preceding sections were used as
catalytic precursors in the asymmetric reduction of acetophenone by transfer
hydrogenation to the chiral alcohol 1-phenylethanol. The catalytic runs were
carried out using a 1% ruthenium complex (C1', C2', C3-C6, C8) and 5% of
potassium tert-butoxide as base, in isopropanol as solvent (Scheme 4).
Scheme 4. Reaction of ruthenium complexes in asymmetric hydrogenation catalysis.
The reactions were carried out under nitrogen atmosphere in refluxing
isopropanol (82 ºC). This solvent also plays the role of hydrogen donor, being
oxidized to acetone. The catalytic precursor was initially dissolved in the basic
isopropanol solution and stirred for 15 min to form the catalytic Ru-hydride
species and then acetophenone was added. At regular intervals (usually 1, 3, 5
and 7 h), aliquots were extracted and analyzed by gas chromatography, using a
chiral column. This allowed the separation of the starting acetophenone and the
two enantiomers of 1-phenylethanol and therefore for each injection the
conversion and enantioselectivity could be immediately determined. For the
sake of reproducibility, for each precursor two catalytic runs were routinely
carried out in parallel.

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The results of conversion and enantioselectivity obtained with cyclometallated
precursors C, along with those with C’ [15,16] for comparison are given in Table
1
.
Entry
Precursor
Conversion (%)
at 1/3/5/7 h
23/46/64/>99
13/27/39/50
25/54/70/76
48/83/96/>99
70/99/>99/>99
20/48/63/73
8/27/40/53
ee(%) 5 h
1
2
3
4
5
6
7
8
9
C1’
C2’
C3
7
16
<5
C4
<5
C5
<5
C6
8
C8
5
C3’
C4’
C5’
C6’
C8’
<5/20/50/75
10/52/75/85
5/22/35/45
<5
13
1
1
1
0
1
2
<5
<5/9/60/80
5
8/24/39/-
6 (24 h)
Table 1. Catalytic results in the asymmetric hydrogenation
.
It has to be pointed out that the reactions were very clean since only the peaks
of starting acetophenone and its reduction products were detected in the GC
traces. The table shows that all the precursors were active in the reaction,
leading to full or high conversions at 7 h for most of the cases.
The different activity of coordination compounds C’, in relation to
cyclometallated complexes C, show that the cyclometallation reaction does not
occur during the catalytic process.
It can be seen that for the 1-naphthyl- and 9-phenanthrylphosphines, some of
the cyclometallated complexes are more active than the dichloro complexes (cf.
entries 3-6 with 8-11) while there is almost no difference in the case of the

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complexes with ligand L8 (cf. entries 7 and 12). This effect is especially relevant
for phosphinite L5 because complex C5 is the only one to gives full conversion
already in 2 h (entry 5) while complex C5’ is one of the less active precursors,
yielding only 45% conversion at 7 h (entry 10). It would have been very
interesting to explore if the other two cyclometallated complexes with
phosphinite ligands, C7 and C9, give also very active precursors, but
unfortunately they could not be obtained in enough quantity to perform
catalysis. Further studies will be directed to obtain those complexes in better
yield and study their catalytic properties.
It should be noted that the enantioselectivity does not improve due to the
cyclometallation. Despite the creation of a new stereocentre at the ruthenium
atom most of the systems are completely unselective, giving racemic 1-
phenylethanol. Only precursors C2’ and C4’, containing the bulkiest ligands
bearing the i-Pr group produced some ee, although still very low (entries 2 and
9
).
From data obtained so far, it is clear that the cyclometallated complexes
containing the 1-naphthyl group, C3-C5, are the fastest precursors of all the
compounds studied. Perhaps the formation of these metallacycle facilitates the
formation of the hydride ruthenium catalyst because it possibly modifies the
reactivity of the metal-chloro bond and/or stabilizes to some extent the hydride
derivative.
3
Conclusions
In this paper some subtleties of the cycloruthenation reaction have been
uncovered. Firstly, the unsuccessful cyclometallation of ortho-tolyl ligands L1
and L2 contrasts with Zhu’s successful cyclometallation of diisopropyl(ortho-
tolyl)phosphine [17]. The fact that the structure of L2 is similar to Zhu’s ligand
(the latter has a second isopropyl group and the former a phenyl) highlights the
importance of stereoelectronic effects in the cycloruthenation reaction.
Secondly, we have shown that monophosphines with a polycyclic aromatic
substituent are prone to cyclometallate and that the reaction can be
stereoselective, which may be interesting for applications in asymmetric
catalysis. We are currently working to improve the synthesis of the
cycloruthenated complexes and study their organometallic chemistry and
catalytic applications.

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4
Experimental Section
.1 General considerations
4
All compounds were prepared under a purified nitrogen atmosphere by
standard Schlenk and vacuum-line techniques. The solvents were obtained
from solvent-purification system or purified by standard procedures and kept
under nitrogen.
L1-BH3 and H B-P(Ph)(MeO)(2-tolyl) were prepared according previously
3
reported methods [18,27]. Ligands L3-L9 were prepared via phosphine-boranes
following the Jugé-Stephan methodology as we have previously reported [13a,b
1
4, 16].
1
13
1
NMR spectra were recorded in CDCl at 298 K with Mercury 400 ( H, C-{ H})
3
31
1
and Bruker 400 Avance III HD ( P-{ H}) spectrometers. Chemical shifts are
1
13
1
given in δ values (ppm) relative to SiMe ( H and C-{ H}), and to 85% H PO
4
4
3
31
1
(
P-{ H}). Coupling constants are given in Hz and multiplicity is expressed as:
s (singlet), d (doublet), t (triplet), sept (septuplet) and m (multiplet). The IR
spectra were recorded in a Nicolet iS5 spectrophotometer in KBr, and the main
–1
absorption bands are expressed in cm . High-resolution mass spectrometry
analyses were performed with electrospray ionisation. ESI (+) spectra were
acquired either on an LC/MSD-TOF instrument or on a ZQ mass spectrometer,
utilizing a mixture of H O:CH CN (1:1, v/v) as the eluent. The GC analyses
2
3
were performed on a FID-detector gas chromatograph equipped with a 30 m β-
Dex 225 column.
4
4
.2 Synthesis of the ligands
.2.1 Synthesis of L1, (S)-Methylphenyl(2-tolyl)phosphine
The phosphine-borane L1-BH (0.34 g, 1.08 mmol) was dissolved in 10 mL of
3
morpholine and stirred overnight under inert atmosphere. The solvent was
removed to dryness leading to a crude brown-yellow solid, which was
redissolved in the minimum volume of anhydrous toluene and purified by
column chromatography (alumina, 120 mL of anhydrous toluene). The toluene
was removed under vacuum and the final product was a colourless oil. Yield:
8
8% (0.17 g).

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1
H NMR (CDCl , 400 MHz): δ 7.40 – 7.14 (m, 9H, aromatic), 2.39 (s, 3H, Me),
3
1
.58 (d, J = 4.0 Hz, 3H, Me).
13
1
C-{ H} NMR (CDCl , 101 MHz): δ 137.5 (s), 132.2 (d, J = 18.8 Hz, aromatic),
3
1
30.2 (d, J = 14.2 Hz, aromatic), 128.4 (dd, J = 14.6, 7.9 Hz, aromatic), 126.0
(s, aromatic), 21.2 (d, J = 20.9 Hz, Me), 12.2 (d, J = 13.4 Hz, Me).
31
1
P-{ H} NMR (CDCl , 162 MHz): δ –36.3 (s).
3
4
.2.2 Synthesis L2·BH (S)-Isopropylphenyl(2-tolyl)phosphine-borane
3
The phosphinite-borane H B-P(Ph)(MeO)(2-tolyl) (0.68 g, 2.8 mmol) was
3
dissolved in 20 mL of anhydrous diethyl ether and the solution was cooled to –
2
5 ºC. 3 equivalents of a solution of iPrLi in pentane (8.5 mL, 5.92 mmol) were
added. Starting at –20 ºC, the temperature was sequentially increased (10 ºC
every 30 minutes) to room temperature and the solution was stirred for one
hour. Carefully, around 20 mL of water were added to the pink solution, which
turned white. The suspension was extracted with diethyl ether (3 x 30 mL) and
the combined organic phases were washed with water and dried with
anhydrous sodium sulphate. The suspension was filtered and the solvents were
evaporated to dryness, leading to a colourless oil. Yield: 91% (0.46 g).
+
+
MS(EI) m/e: 253.1318 ([M-3H]+), 279.1448 ([M+Na] ), 535.2981 ([2M+Na] ).
1
H NMR (CDCl , 400 MHz): δ 7.75 (ddd, J = 10.6, 7.7, 1.4 Hz, 1H, aromatic),
3
7
2
.66 – 7.54 (m, 2H, aromatic), 7.49 – 7.28 (m, 4H, aromatic), 7.23 – 7.08 (m,
H, aromatic), 2.78 (m, 1H, CHMe ), 2.18 (s, 3H, Me), 1.24 (dd, J = 16.4, 7.0
2
Hz, 3H, Me CH), 1.15 (dd, J = 15.1, 6.9 Hz, 3H, Me CH), 1.85 – 0.40 (q, br, 3H,
2
2
BH3).
31
1
P-{ H} NMR (CDCl , 162 MHz): δ +25.9 (d, J = 65.9 Hz).
3
4
.2.3 Synthesis of L2 (S)-Isopropylphenyl(2-tolyl)phosphine
The phosphine-borane L2·BH (0.20 g, 0.79 mmol) was dissolved in 10 mL of
3
morpholine and stirred overnight under inert atmosphere. The solvent was
evaporated to dryness leading to a crude brown-yellow solid, which was
redissolved in the minimum volume of anhydrous toluene and purified by
column chromatography (alumina, 120 mL of anhydrous toluene). The toluene
was removed under vacuum and the final product was colourless oil. Yield: 80%
(0.15 g).

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1
H NMR (CDCl , 400 MHz): δ 7.47 (m, 1H), 7.44 – 7.38 (m, 2H, aromatic), 7.31
3
–
1
7.13 (m, 6H, aromatic), 2.86 (m, 1H, CHMe ), 2.40 (s, 3H, Me), 1.15 (dd, J =
2
6.2, 6.9 Hz, 3H,CHMe ), 1.03 (dd, J = 15.2, 6.9 Hz, 3H, CHMe ).
2
2
13
1
C-{ H} (CDCl , 101 MHz): δ 143.1 (d, J = 24.3 Hz, aromatic), 137.4 (d, J =
3
1
3.9 Hz, aromatic), 136.0 (s, aromatic), 133.7 (d, J = 19.1 Hz, aromatic), 130.9
(
s, aromatic), 130.3 (d, J = 4.8 Hz, aromatic), 128.5 (d, J = 11.3 Hz, aromatic),
28.2 (s, aromatic), 128.1 (s, aromatic), 24.7 (d, J = 8.1 Hz), 21.5 (d, J = 22.2
Hz), 20.0 (d, J = 19.9 Hz), 19.6 (d, J = 18.2 Hz).
1
31
1
P-{ H} NMR (CDCl , 162 MHz): δ –11.3 (s).
3
4
4
.3 Synthesis of complexes
.3.1 Synthesis of C1’
Ligand L1 (162.6 mg, 0.76 mmol), [RuCl (p-cymene)] (214.3 mg, 0.35 mmol)
2
2
and sodium acetate (164.1 mg, 2 mmol) were dissolved in 80 mL of methanol
and the solution was stirred at room temperature for 4 h. The solvent was then
removed under vacuum, and the residue was chromatographed on a silica gel
column with first CH Cl , later with CH Cl /Et O and finally with methanol. The
2
2
2
2
2
title product was obtained as an orange solid. Yield 85 mg (20%).
1
H NMR (CDCl , 400 MHz): δ 7.95 (ddd, J = 12.8, 7.6, 1.2 Hz, 1H, aromatic),
3
7
.71-7.66 (m, 2H, aromatic), 7.44-7.32 (m, 5H, aromatic), 7.27-7.24 (m, 1H,
6
6
aromatic), 5.33 (d, J = 6.4 Hz, 1H, η -C H ), 5.25 (d, J = 6 Hz, 1H, η -C H ),
6
4
6
4
6
6
5
=
3
.21 (d, J = 5.6 Hz, 1H, η -C H ), 5.10 (d, J = 6 Hz, 1H, η -C H ), 2.61 (sept., J
6 4 6 4
7.2 Hz, 1H, CHMe ), 2.14 (s, 3H, Me), 2.02 (d, J = 10.8 Hz, 3H, MeP), 1.95 (s,
2
H, Me), 0.98 (d, J = 7.2 Hz, 3H, CHMe ), 0.91 (d, J = 7.2 Hz, 3H, CHMe ).
2
2
13
1
C-{ H} NMR (CDCl , 101 MHz): phenyl carbon signals δ = 141.36 (d, J = 4.2
3
Hz, 135.94, 135.50, 135.35, 133.30, 132.89, 132.17 (d, J = 7.0 Hz), 131.58 (d, J
=
1
4
9.1 Hz), 130.81 (d, J = 2.4 Hz), 129.95 (d, J = 2.4 Hz), 128.40 (d, J = 9.7 Hz),
6
25.54 (d, J = 11.4 Hz); η -C H carbon signals δ = 107.96, 94.86, 89.97 (d, J =
6
4
.6 Hz), 89.61 (d, J = 4.5 Hz), 86.51 (d, J = 5.9 Hz), 84.96 (d, J = 5.5 Hz); alkyl
carbon signals δ = 29.95, 23.10 (d, J = 3.9 Hz), 21.58, 21.43, 17.32, 13.65 (d, J
=
35.2 Hz).
31
1
P-{ H} NMR (CDCl , 162 MHz): δ 19.9 ppm.
3
4
.3.2. Synthesis of C2'

ACCEPTED MANUSCRIPT
The procedure was the same as the one followed to prepare C1. Starting from
L2 (182.2 mg, 0.75 mmol). The title product was obtained as an orange solid.
Yield 289.3 mg (66%).
IR: 3043, 2957, 2917, 2861, 1630, 1465, 1430, 1378, 1261, 1022, 796, 743,
6
96, 552, 530.478.
+
+
HRMS (ESI): m/z calc. for C H PClRu [M-Cl] 513.1046; found 513.1047
26
33
1
H NMR (CDCl , 400 MHz): δ 8.10 (br, 1H, aromatic); 7.60 (br, 1H, aromatic),
3
6
6
7
.50-7.29 (m, 7H, aromatic), 5.22 (br., 1H, η -C H ), 5.01 (d, J = 6 Hz, 1H, η -
6 4
6
6
C H ), 4.81 (br., 1H, η -C H ), 4.69 (br., 1H, η -C H ), 3.39-3.52 (m, 1H,
6
4
6
4
6
4
PCHMe ), 2.81 (sept., J = 14 Hz, 1H, CHMe ), 2.57 (br., 3H, Me), 1.92 (s, 3H,
2
2
Me), 1.14-1.05 (m, 9H, CHMe ), 0.95-0.85 (br m, 3H, CHMe ).
2
2
31
1
P-{ H} NMR (CDCl , 162 MHz): δ 40.0.
3
4
.3.3 Synthesis of C3
The procedure was the same as the one followed to prepare C1. Starting from
ligand L3 (200 mg, 0.8 mmol), the title product was obtained as a brown solid.
Yield 70.1 mg (17%).
IR: 1630, 1543, 1482, 1467, 1434, 1384, 1340, 1193, 1099, 1036, 987, 888,
8
12, 775, 746, 729, 700, 500, 481, 472.
+
+
HRMS (ESI): m/z calc. for C H PRu [M-Cl] 485.0966; found 485.0977.
27
28
1
Major isomer: H NMR (CDCl , 400 MHz): δ 8.28-8.24 (m, 1H, aromatic), 7.80
3
6
(
m, 1H, aromatic), 7.52-7.24 (m, 9H, aromatic), 5.71 (d, J = 6 Hz, 1H, η -C H ),
6
4
6
6
5
5
.53 (d, J = 6 Hz, 1H, η -C H ), 4.77 (d, J = 6.4 Hz, 1H, η -C H ), 4.04 (d, J =
6 4 6 4
6
.6 Hz, 1H, η -C H ), 2.45 (sept., J = 14 Hz, CHMe ), 2.17 (d, J = 10.8 Hz, 3H,
6
4
2
MeP), 1.73 (s, 3H, Me), 1.09 (d, J = 6.8. Hz, 3H, CHMe ), 0.86 (d, J = 6.8. Hz,
2
3
H, CHMe2).
13
1
C-{ H} NMR (CDCl , 101 MHz): phenyl carbon signals δ = 170.54 (d, J = 13.1
3
Hz), 140.02, 139.45, 138.86, 138.36, 133.24 (d, J = 15.7 Hz), 130.77 (d, J = 2.5
Hz), 130.10 (d, J = 9.2 Hz), 129.77 (d, J = 2.5 Hz), 128.51 (d, J = 9.5 Hz),
6
1
27.7-127.3 (multiplet), 124.58 (d, J = 8.3 Hz), 121.48, η -C H carbon signals δ
6
4
=
108.6, 97.8, 95.4 (d, J = 5.6 Hz), 91.7 (d, J = 3.4 Hz, major), 90.8 (d, J = 6.1
Hz), 86.7 (d, J = 3.6 Hz); alkyl carbon signals δ = 30.2, 23.1, 21.6, 18.42, 13.1
d, J = 32.0 Hz).
(

ACCEPTED MANUSCRIPT
31
1
P-{ H} NMR (CDCl , 162 MHz): δ 56.4.
3
1
Minor isomer H NMR (CDCl , 400 MHz): δ 8.28-8.24 (m, 1H, aromatic), 7.80
3
6
(
m, 1H, aromatic), 7.52-7.24 (m, 9H minor, aromatic), 5.97 (d, J = 6 Hz, 2H, η -
6
6
C H ), 5.16 (d, J = 6 Hz, 1H, η -C H ), 5.03 (d, J = 5.6 Hz, 1H, η -C H ), 2.45
6
4
6
4
6
4
(
sept., J = 14 Hz, 1H, CHMe ), 2.16 (d, J = 9.2 Hz, 3H, MeP), 1.87 (s, 3H, Me),
2
0
.95 (d, J = 6.8. Hz, 3H, CHMe ), 0.80 (d, J = 6.8 Hz, 3H, CHMe ).
2 2
13
1
C-{ H} NMR (CDCl , 101 MHz): phenyl carbon signals δ = 170.54 (d, J = 13.1
3
Hz), 139.45, 138.03, 137.52, 134.85, 134.37, 133.30 (d, J = 15.7 Hz), 131.18
(d, J = 9.1 Hz), 130.93 (d, J = 2.5 Hz), 129.40 (d, J = 3.0 Hz, minor), 128.51 (d,
6
J = 9.5 Hz), 127.7-127.3 (multiplet), 124.33 (d, J = 8.3 Hz), 121.37 minor; η -
C H carbon signals δ = 107.1, 99.1, 94.6 (d, J = 4.8 Hz), 92.8 (d, J = 4.3 Hz),
6
4
8
2
7.8 (d, J = 4.8 Hz), 87.2 (d, J = 4.8 Hz) alkyl carbon signals δ = 30.41, 22.3,
1.9, 19.4 (d, J = 32.1 Hz), 18.46, 15.25.
31
1
P-{ H} NMR (CDCl , 162 MHz): δ 51.9.
3
4
.3.4 Synthesis of C4
The procedure was the same as the one followed to prepare C1. Starting from
L4 (164.3 mg, 0.59 mmol), the title product was obtained as a brown solid. Yield
5
2.8 mg (12%).
1
H NMR (CDCl , 400 MHz): δ 8.26 (d, J = 6.8 Hz, 1H, aromatic), 7.83 (d, J = 6.4
3
6
Hz, 1H, aromatic), 7.78-7.29 (m, 9H, aromatic), 5.66 (d, J = 6.4 Hz, 1H, η -
6
6
C H ), 5.64 (d, J = 7.6 Hz, 1H, η -C H ), 4.58 (d, J = 6.4 Hz, 1H, η -C H ), 4.08
6
4
6
4
6
4
6
(
d, J = 6 Hz, 1H, η -C H ), 2.81 (sept., J = 7.6 Hz, 1H, CHMe ), 2.32-2.16 (m,
6 4 2
1
H, PCHMe ), 1.81(s, 3H), 1.55 (dd, J = 16.8, 7.2 Hz, 3H, PCHMe ), 1.25 (dd, J
2 2
=
14.4, 7.2 Hz, 3H, PCHMe ), 0.94 (d, J = 7.0, 3H, CHMe ), 0.52 (d, J = 6.8, 3H,
2 2
CHMe2).
13
1
C-{ H} NMR (CDCl , 101 MHz): phenyl carbon signals δ = 170.04 (d, J = 12.8
3
Hz), 149.10 (d, J = 35.2 Hz), 138.95, 135.75 (d, J = 12.3 Hz), 132.53 (d, J =
1
1
5.2 Hz), 130.40 (d, J = 8.0 Hz), 129.82 (d, J = 2.6 Hz), 128.66 (d, J = 2.4 Hz),
6
28.32, 127.31 (d, J = 8.9 Hz), 126.14, 122.75 (d, J = 7.6 Hz), 120.43; η -C H
6
4
carbon signals δ = 105.3, 98.8, 93.9 (d, J = 3 Hz), 93.4 (d, J = 5.1 Hz), 90.9 (d,
J = 5.8 Hz), 83.7 (d, J = 2.9 Hz); alkyl carbon signals δ = 29.1, 26.37 (d, J =
2
5.5 Hz), 21.6, 20.7, 17.7 (d, J = 3.9 Hz), 17.1.

ACCEPTED MANUSCRIPT
31
1
P-{ H} NMR (CDCl , 162 MHz): δ 76.6 ppm.
3
IR: 3039, 2957, 2857, 1561, 1435, 1378, 1265, 1096, 1043, 813, 778, 704, 635,
30.
HRMS (ESI): m/z calc. for C H PRu [M-Cl] 513.1279; found 513.1297.
5
+
+
29
32
4
.3.5 Synthesis of C5
The procedure was the same as the one followed to prepare C1. Starting from
L5 (226.1 mg, 0.85 mmol), the title product was obtained as a brown solid. Yield
5
4.3 mg (13%).
IR: 3039, 2922, 2848, 2357, 2335, 1026, 809, 770, 696, 665, 565, 530.
+
+
HRMS (ESI): m/z calc. for C H OPRu [M-Cl] 501.0915; found 501.0923.
27
28
1
Major: H NMR (CDCl , 400 MHz): δ 8.32 (dd, J = 7.0, 1.1 Hz, 1H, aromatic),
3
7
1
.89-7.83 (m, 1H, aromatic), 7.75-7.32 (m, 9H, aromatic), 5.96 (d, J = 6 Hz,
6
6
6
H, η -C H ), 5.94 (d, J = 6.4 Hz, 1H, η -C H ), 5.49 (d, J = 6.4 Hz, 1H, η -
6
4
6
4
6
C H ), 5.12 (d, J = 6.4 Hz, 1H, η -C H ), 3.47 (d, J = 10.8 Hz, 3H, MeO), 2.45
6
4
6
4
(
m, 1H, CHMe ), 1.96 (s, 3H, Me), 1.13 (d, J = 7.1 Hz, 3H, CHMe ), 0.96 (d, J =
2
2
7
.2 Hz, 3H, CHMe2).
31
1
P-{ H} NMR (CDCl , 162 MHz): δ 162.6.
3
1
Minor: H NMR (CDCl , 400 MHz): δ 8.29 (dd, J = 7.0, 1.0 Hz, 1H, aromatic),
3
7
.89-7.83 (m, 1H, aromatic), 7.75-7.32 (m, 9H, aromatic), 5.86 (d, J = 6 Hz, 1H,
6
6
6
η -C H ), 5.74 (d, J = 6.0 Hz, 1H, η -C H ), 4.83 (d, J = 6.8 Hz, 1H, η -C H ),
6
4
6
4
6
4
6
4
.05 (d, J = 6.4 Hz, 1H, η -C H ), 3.76 (d, J = 11.6 Hz, 3H, MeO), 2.45 (m, 1H,
6 4
CHMe ), 1.72 (s, 3H, Me), 1.10 (d, J = 7.2 Hz, 3H, CHMe ), 1.01 (d, J = 6.8 Hz,
2
2
3
H CHMe2).
31
1
P-{ H} NMR (CDCl , 162 MHz): δ 154.2.
3
4
.3.6 Synthesis of C6
The procedure was the same as the one followed to prepare C1. Starting from
ligand L6 (240.1 mg, 0.8 mmol), the title product was obtained as a brown solid.
Yield 324.1 mg (71%).

ACCEPTED MANUSCRIPT
IR: 3430, 3039, 2957, 2917, 2852, 2356, 1709, 1622, 1557, 1465, 1422, 1383,
1
4
326, 1274, 1187, 1100, 1030, 948, 883, 843, 748, 722, 691, 622, 600, 491,
22.
+
+
HRMS (ESI): m/z calc. for C H PRu [M-Cl] 535.1123; found 535.1132.
31
30
1
Major: H NMR (CDCl , 400 MHz): δ 8.71 (d, J = 8.3 Hz, 1H, aromatic), 8.40 (d,
3
J = 7.2, 1H, aromatic), 8.26, (m,1H, aromatic), 7.80-7.30 (m, 10H, aromatic),
6
6
5
.71 (d, J = 6 Hz, 1H, η -C H ), 5.53 (d, J = 6 Hz, 1H, η -C H ), 4.77 (d, J = 6.4
6 4 6 4
6
6
Hz, 1H, η -C H ), 4.13 (d, J = 6 Hz, 1H, η -C H ), 2.40-2.50 (m, 1H, CHMe ),
6
4
6
4
2
2
.22 (d, J = 10.8 Hz, 3H, MeP), 1.73 (s, 3H, Me), 1.08 (d, J = 7.2 Hz, 3H,
CHMe ), 0.86 (d, J = 6.8. Hz, 3H, CHMe ).
2
2
31
1
P-{ H} NMR (CDCl , 162 MHz): δ 56.4.
3
1
Minor: H NMR (CDCl , 400 MHz): δ 8.69 (d, J = 8.2 Hz, 1H, aromatic), 8.38 (d,
3
J = 7.2, 1H, aromatic), 8.26, (m,1H, aromatic), 7.80-7.30 (m, 10H, aromatic),
6
6
5
.97 (d, J = 6 Hz, 2H, η -C H ), 5.20 (d, J = 6 Hz, 1H, η -C H ), 5.06 (d, J = 6.4
6 4 6 4
6
Hz, 1H, η -C H ), 2.40-2.50 (m, 1H, CHMe ), 2.25 (d, J = 9.6 Hz, 3H, MeP),
6
4
2
1
.87 (s, 3H, Me), 0.96 (d, J = 6.8. Hz, 3H, CHMe ), 0.83 (d, J = 6.8 Hz, 3H,
2
CHMe2).
13
1
C-{ H} NMR (CDCl , 101 MHz): selected phenyl carbon signals, major and
3
minor derivatives δ = 172.15 (d, J = 14.0 Hz), 145.75 (d, J = 36.3 Hz), 141.38,
1
1
9
30.26 (d, J = 9.1 Hz), 129.87 (d, J = 2.5 Hz), 127.41 (d, J = 25.9 Hz), 125.95,
6
23.25, 116.68; η -C H carbon signals δ = 108.5 (s, major), 107.1 (s, minor),
6
4
9.4 (s, minor), 98.3 (s, major), 95.6 (d, J = 5.6 Hz, major), 94.8 (d, J = 4.8 Hz,
minor), 93.2 (d, J = 4.4 Hz, minor), 92.2 (d, J = 3.6 Hz, major), 90.9 (d, J = 5.9
Hz, major), 87.9 (d, J = 4.9 Hz, minor), 87.6 (d, J = 4.4 Hz, minor), 87.0 (d, J =
3
.8 Hz, major); alkyl carbon signals δ = 30.4 (s, minor), 30.3 (s, major), 23.2 (s,
major), 22.5 (s, minor), 22.1 (s, minor), 21.6 (s, major), 19.2 (d, J = 32.2, minor),
1
8.5 (minor), 18.4 (major), 13.6 (d, J = 32.0, major).
31
1
P-{ H} NMR (CDCl , 162 MHz): δ 51.2.
3
4
.3.7 Synthesis of C7
The procedure was the same as the one followed to prepare C1. Starting from
L7 (258.9 mg, 0.80 mmol), the title product was obtained as a brown solid. Yield
2
6.8 mg (6%).

ACCEPTED MANUSCRIPT
IR: 3057, 2957, 2913, 2847, 2361, 2322, 1709, 1613, 1552, 1430, 1383, 1309,
100, 1035, 948, 800, 757, 687, 609, 570, 465.
1
+
+
HRMS (ESI): m/z calc. for C H OPRu [M-Cl] 551.1072; found 551.1057.
31
30
1
Major: H NMR (CDCl , 400 MHz): δ 8.72 (m, 1H, aromatic), 8.62 (d, J = 7.2 Hz,
3
1
=
1
2
H, aromatic), 8.29 (m, 1H, aromatic), 7.85-7.40 (m, 10H, aromatic), 5.93 (d, J
6
6
6.4 Hz, 1H, η -C H ), 5.54 (d, J = 6.0 Hz, 1H, η -C H ), 5.47 (d, J = 6.4 Hz,
6
4
6
4
6
6
H, η -C H ), 4.22 (d, J = 6.4 Hz, 1H, η -C H ), 3.60 (d, J = 11.2 Hz, 3H, MeO),
6
4
6
4
.38 (sept., J =14, 1H, CHMe ), 1.68 (s, 3H, Me), 1.22 (d, J = 7.2 Hz, 3H,
2
CHMe ), 1.07 (d, J = 6.8 Hz, 3H, CHMe ).
2
2
31
1
P-{ H} NMR (CDCl , 162 MHz): δ 158.2.
3
1
Minor: H NMR (CDCl , 400 MHz): δ 8.72 (m, 1H, aromatic), 8.58 (d, J = 7.2 Hz,
3
1
H, aromatic), 8.29 (m, 1H, aromatic), 7.85-7.40 (m, 10H, aromatic), 6.10 (d, J
6
6
=
5.2 Hz, 1H, η -C H ), 6.0 (d, J = 6.4 Hz, 1H, η -C H ), 5.86 (d, J = 5.6 Hz, 1H,
6
4
6
4
6
6
η -C H ), 5.02 (d, J = 5.2 Hz, 1H, η -C H ), 3.61 (d, J = 11.2 Hz, 3H, MeO),
6
4
6
4
2
1
.46 (sept., J =14, 1H, minor), 2.38 (sept., J =14, 1H, CHMe ), 1.93 (s, 3H, Me),
2
.24 (d, J = 6.8 Hz, 3H, CHMe ), 0.87 (d, J = 6.8 Hz, 3H, CHMe ).
2
2
31
1
P-{ H} NMR (CDCl , 162 MHz): δ 168.4.
3
4
.3.8 Synthesis of C8
The procedure was the same as the one followed to prepare C1. Starting from
Ligand L8 (244.6 mg, 0.75 mmol), the title product was obtained as a brown
solid. Yield 32 mg (7%).
IR: 3030, 2957, 2917, 2867, 1709, 1622, 1596, 1574, 1513, 1439, 1387, 1278,
1
170, 1113, 1030, 883, 839, 800, 726, 691, 596, 491.
+
+
HRMS (ESI): m/z calc. per C H PRu [M-Cl] 559.1123; found 559.1133.
33
30
1
Major: H NMR (CDCl , 400 MHz): δ 8.91 (s, 1H, aromatic), 8.20-7.30 (m, 12H,
3
6
6
aromatic), 6.12 (d, J = 6.4 Hz, 1H, η -C H ), 5.68 (d, J = 6 Hz, 1H, η -C H ),
6
4
6
4
6
6
4
6
=
.87 (d, J = 6 Hz, 1H, η -C H ), 4.14 (d, J = 6 Hz, 1H, η -C H ), 2.55 (sept., J =
6 4 6 4
.8 Hz, 1H, CHMe ), 2.29 (d, J = 10.8 Hz, 3H, MeP), 1.80 (s, 3H, Me), 1.13 (d, J
2
6.8 Hz, 3H, CHMe ), 0.87 (d, J = 6.8. Hz, 3H, CHMe ).
2
2
31
1
P-{ H} NMR (CDCl , 162 MHz): δ 56.7.
3

ACCEPTED MANUSCRIPT
1
Minor: H NMR (CDCl , 400 MHz): δ 8.89 (1H, aromatic), 8.20-7.30 (m, 12H,
3
6
6
aromatic), 5.87 (d, J = 6.4 Hz, 2H, η -C H ), 5.25 (d, J = 6 Hz, 1H, η -C H ),
6
4
6
4
6
5
.16 (d, J = 6.4 Hz, 1H, η -C H ), 2.55 (sept., J = 6.8 Hz, 1H, CHMe ), 2.29 (d,
6 4 2
J = 10.8 Hz, 3H, MeP), 1.94 (s, 3H, Me), 0.99 (d, J = 6.8. Hz, 3H, CHMe ), 0.79
2
(d, J = 6.8 Hz, 3H, CHMe2).
31
1
P-{ H} NMR (CDCl , 162 MHz): δ 51.9.
3
4
.3.9 Synthesis of C9
The procedure was the same as the one followed to prepare C1. Starting from
L9 (272.1 mg, 0.80 mmol), the title product was obtained as a brown solid. Yield
2
0 mg (4%).
IR: 3052, 2965, 2926, 2861, 2357, 2222, 1709, 1613, 1565, 1470, 1435, 1383,
300, 1257, 1183, 1104, 1030, 843, 735, 696, 604, 574, 522, 457.
1
+
+
HRMS (ESI): m/z calc. for C H OPRu [M-Cl] 575.1072; found 575.1077.
33
30
1
Major: H NMR (CDCl , 400 MHz): δ 9.25 (s, 1H, aromatic), 8.13 (dd, J = 6.9,
3
6
1
.8 Hz, 1H, aromatic), 7.70-6.80 (m, 11H, aromatic), 5.74 (d, J = 6.4 Hz, 1H, η -
6
6
C H ), 5.58 (d, J = 5.6 Hz, 1H, η -C H ), 5.14 (d, J = 6 Hz, 1H, η -C H ), 3.62
6
4
6
4
6
4
6
(
d, J = 6.0 Hz, 1H, η -C H ), 3.27 (d, J = 11.2 Hz, 3H, POMe), 2.43 (m, 1H,
6 4
CHMe ), 1.61 (s, 3H, Me), 0.87 (d, J = 7.2 Hz, 3H, CHMe ), 0.51 (d, J = 6.8 Hz,
2
2
3
H, CHMe2).
31
1
P-{ H} NMR (CDCl , 162 MHz): δ 158.4.
3
1
Minor: H NMR (CDCl , 400 MHz): δ 9.16 (s, 1H, aromatic), 8.08 (dd, J = 7.1,
3
6
1
.6 Hz, 1H, aromatic) 7.70-6.80 (m, 11H, aromatic), 5.90 (d, J = 6.8 Hz, 1H, η -
6
6
C H ), 5.83 (d, J = 6.4 Hz, 1H, η -C H ), 5.40 (d, J = 6 Hz, 1H, η -C H ), 4.52
6
4
6
4
6
4
6
(
d, J = 6.0 Hz, 1H, η -C H ), 3.27 (d, J = 11.2 Hz, 3H, major), 2.84 (d, J = 11.2
6 4
Hz, 3H, POMe), 2.43 (m, 1H, CHMe ), 1.86 (s, 3H, Me), 0.70 (d, J = 7.2 Hz, 3H,
2
CHMe ), 0.49 (d, J = 6.8 Hz, 3H, CHMe ).
2
2
31
1
P-{ H} NMR (CDCl , 162 MHz): δ 168.1.
3
4
.4 X-ray crystallography
The X-ray intensity data were measured on a D8 Venture system equipped with
a multilayer monochromator and a Mo microfocus (λ = 0.71073 Å). The frames

ACCEPTED MANUSCRIPT
were integrated with the Bruker SAINT software package using a narrow-frame
algorithm. The structure was solved and refined using the Bruker SHELXTL
Software Package [28]. CCDC 1907310-1907312 contain the supplementary
data for this paper. These data can be obtained free of charge from the
Cambridge
www.ccdc.cam.ac.uk/data_request/cif.
.5 General Procedure For Transfer Hydrogenation Reactions
Crystallographic
Data
Centre
via
4
Transfer hydrogenation reactions of acetophenone were carried out in 100 mL
Schlenk flasks and in pairs in order to improve the reproducibility of the data.
Under a nitrogen atmosphere, the Schlenk flask was charged with 0.02 mmol
(
1%) of the ruthenium complex and 0.10 mmol of potassium tert-butoxide. The
solids were dissolved in 25 mL of 2-propanol and the mixture was left stirring for
5 minutes at reflux to activate the catalyst. At this point, 4.0 mmol of
acetophenone were added to start the reaction. At regular intervals of time (1,
, 5 and 7 h) aliquots were extracted and analysed by gas chromatography, in
1
3
order to study the conversion of the reaction and the enantioselectivity of the
process.
Acknowledgments
Financial support from the Ministerio de Economía y Competitividad, grant
number CTQ2015 65040-P is gratefully acknowledged.
Dedicated to Prof. Pascual Royo in appreciation of his outstanding contributions
to organometallic chemistry.
5
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The P-stereogenic ligands were prepared via phosphine-boranes following the Jugé-Stephan
methodology
2
Ruthenium cyclometallated (
-C,P) complexes were obtained with phosphines containing a
polycyclic aromatic group: 1-naphthyl, 9-phenanthryl or 1-pyrenyl
Some diastereoselectivity in the cyclometallation process has been observed for the most bulky
ligands, and in one case the reaction had taken place diastereoselectively
Some cyclometallated complexes are much more active than the dichloro complexes as
catalytic precursors in the reduction of acetophenone to 1-phenylethanol by transfer
hydrogenation