C?H Bond Activation/Arylation Catalyzed by Arene–Ruthenium–Aniline Complexes in Water

Article abstract of DOI:10.1002/asia.201600954

Water-soluble arene–ruthenium complexes coordinated with readily available aniline-based ligands were successfully employed as highly active catalysts in the C?H bond activation and arylation of 2-phenylpyridine with aryl halides in water. A variety of (hetero)aryl halides were also used for the ortho-C?H bond arylation of 2-phenylpyridine to afford the corresponding ortho- monoarylated products as major products in moderate to good yields. Our investigations, including time-scaled NMR spectroscopy and mass spectrometry studies, evidenced that the coordinating aniline-based ligands, having varying electronic and steric properties, had a significant influence on the catalytic activity of the resulting arene–ruthenium–aniline-based complexes. Moreover, mass spectrometry identification of the cycloruthenated species, {(η⁶-arene)Ru(κ²-C,N-phenylpyridine)}⁺, and several ligand-coordinated cycloruthenated species, such as [(η⁶-arene)Ru(4-methylaniline)(κ²-C,N-phenylpyridine)]⁺, found during the reaction of 2-phenylpyridine with the arene–ruthenium–aniline complexes further authenticated the crucial roles of these species in the observed highly active and tuned catalyst. At last, the structures of a few of the active catalysts were also confirmed by single-crystal X-ray diffraction studies.

Full text of DOI:10.1002/asia.201600954

CHEMISTRY
AN ASIAN JOURNAL
www.chemasianj.org
Accepted Article
Title: C-H Bond Activation/Arylation Catalyzed by Arene-Ruthenium-Aniline Comple-
xes in Water
Authors: Chinky Binnani; Deepika Tyagi; Rohit Kumar Rai; Shaikh M. Mobin; Sanjay
Kumar Singh
This manuscript has been accepted after peer review and the authors have elected
to post their Accepted Article online prior to editing, proofing, and formal publication
of the final Version of Record (VoR). This work is currently citable by using the Digital
Object Identifier (DOI) given below. The VoR will be published online in Early View as
soon as possible and may be different to this Accepted Article as a result of editing.
Readers should obtain the VoR from the journal website shown below when it is pu-
blished to ensure accuracy of information. The authors are responsible for the content
of this Accepted Article.
To be cited as: Chem. Asian J. 10.1002/asia.201600954
Link to VoR: http://dx.doi.org/10.1002/asia.201600954
A Journal of
A sister journal of Angewandte Chemie
and Chemistry – A European Journal

Chemistry - An Asian Journal
10.1002/asia.201600954
C-H Bond Activation/Arylation Catalyzed by Arene-Ruthenium-Aniline
Complexes in Water
Chinky Binnani,†[a] Deepika Tyagi,†[a] Rohit K. Rai,[a] Shaikh M. Mobin,[a] and
Sanjay K. Singh*[a][b]
[a] Discipline of Chemistry, School of Basic Sciences, Indian Institute of Technology (IIT) Indore,
Indore 453552, India
[b] Discipline of Metallurgy Engineering and Materials Science, Indian Institute of Technology
(IIT) Indore, Indore 453552, India
† These authors contributed equally to this work.
Abstract
Water-soluble arene-ruthenium complexes coordinated with readily available aniline based
ligands were successfully employed to achieve high catalytic activity towards C-H bond
activation and arylation of 2-phenylpyridine with arylhalides in water. A variety of
(hetero)arylhalides were also used for the ortho-C-H bond arylation of 2-phenylpyridine to
afford the corresponding ortho- monoarylated products as major products in moderate to good
yields. Our investigations, including time-scaled NMR and mass spectral studies, evidenced that
the coordinating aniline based ligands, having varying electronic and steric behavior, exert
significant influence on the catalytic activity of the resulting arene-ruthenium-aniline based
complexes. Moreover, mass spectral identification of the cycloruthenated species, {(6-
arene)Ru(κ2-C,N-phenylpyridine)}+, and several ligand coordinated cycloruthenated species,
such as [(6-arene)Ru(4-methylaniline)(κ2-C,N-phenylpyridine)]+, during the reaction of 2-
phenylpyridine and arene-ruthenium-aniline complexes, further authenticating the crucial role of
these species in the observed highly active and tuned catalytic activity. At last, structural identity
of few of the active catalysts was also confirmed by single crystal X-ray diffraction studies.
Keywords: C-H bond activation; arylation; ruthenium; aniline ligands; homogeneous catalysis
1
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
Introduction
Transition metal catalyzed C-H bond activation reactions have received extensive attention
because these reactions provide a shorter and atom economic way to synthesize a wide range of
compounds by activating the C-H bond.[1] One of the most explored C-H bond activation
strategies includes those involving a metal directing group as it proceed via the formation of an
active 5-membered cyclometalated species. Among the several transition metals based catalysts
explored for C-H bond activation, ruthenium complexes being highly active, with a wide range
of active and stable oxidation states, high stability in air and water, have gained advantages over
others.[2-6] Hence a wide range of ruthenium complexes such as RuCl2(PPh3)3, [RuCl2(cod)]n,
RuCl3.xH2O and others were extensively investigated for C-H bond activation reaction.[5,6]
Among these, RuCl3.xH2O was the first ligand-free catalytic system reported by Ackermann et
al. for C-H bond activation of (hetero)arenes.[5b][5f] However, arene ruthenium complexes, for
example [{(η6-arene)RuCl2}2] and their analogues, were identified as one of the most promising
and extensively explored ruthenium catalysts for C-H bond activation/functionalization.[5,6]
Recently, double C-H bond activation using rhodium and ruthenium catalysts was also reported
to achieve analogous C-H bond functionalization.[6e]
Scheme 1. Various ligands associated with arene-ruthenium catalyzed C-H bond activation and
functionalization.
2
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
In particular, C-H bond activation using arene ruthenium complexes in the presence of a
wide range of phosphine bound ligands/ additives has been well studied and explored (Scheme
1).[7-14] For instance, Ackermann et al. used phosphoric acids with arene ruthenium catalyst to
enable efficient C-H bond functionalization in toluene.[8b] Recently, C-H bond
activation/arylation over a well defined arene-ruthenium-phosphinous acid catalyst was reported
where phosphinous acids acts as a deprotonating agent.[7e] Moreover, reports inferred that
performing water based catalytic reactions does not only provide a non-toxic greener condition,
but also there are several incremental effects of water on the catalytic reaction. Ackermann et al
first used water as a co-solvent with NMP (1:2 v/v) for the C-H bond arylation of 2-
phenylpyridine in the presence of Ru-p-cymene dimer catalyst with (adamantyl)2P(O)H and
observed that Ru catalysts are active even in water.[8c] Further, Dixneuf et al. investigated the
sequential arylation of 2-phenylpyridine with arylhalides over [{(η6(p-cymene)RuCl2}2]
complexes in the presence of various phosphine based ligands at 80 ºC in water and reported
that in water better catalytic activity and yields can be achieved.[9] Also, for low temperature
reactions (< 100 °C), water is considered even as a more efficient solvent than other organic
solvents (e.g. NMP).[9] Contrary to phosphine based ligands, carboxylates being both a ligand
and deprotonating agent displayed more potential to achieve high catalytic activity and to tune
the selectivity for arene ruthenium catalyzed C-H bond activation reaction.[9c][10] More recently,
we also developed water-soluble arene-ruthenium complexes using troponate/aminotroponate
ligands to achieve superior catalytic activity for C-H bond arylation with arylchlorides in water
at 100 ºC.[12] Our investigations evidenced that having strongly coordinating chelating ligands
arene-ruthenium complexes may led to the release of arene ligand in contrast to the well-
established arene-ruthenium cyclometalated species.
3
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
Our recent studies focused on the development of water-soluble arene-ruthenium
complexes containing aniline ligands inferred that these complexes could be used for the
catalytic synthesis of biaryls via an oxidative homocoupling reaction of arylboronic acids in
water.[15a] Our investigations evidenced the formation of (di-σ-aryl)Ru species as a possible
active intermediate species.[15a] Interestingly, anilines which are considered as a weakly
coordinating ligand exerts substantial role to tune the activity and selectivity towards
homocoupling of arylboronic acids. Notably, [(η6-arene)RuCl2(aniline)] complexes displayed
comparable or even higher activity than their structurally analogous phosphine containing
complex [(η6-arene)RuCl2(PPh3)].[9,15] We envisioned that being a weak ligand, aniline, in
contrary to strongly coordinating phosphine ligand, can be easily displaced by the reacting
substrate under catalytic reaction conditions. Encouraged by these findings, herein we
systematically explored the catalytic activity of arene-ruthenium complexes containing aniline
based ligands for ortho-C-H bond activation and arylation of 2-phenylpyridine with arylchlorides
in water. We also investigated the influence of having aniline based ligands of varying electronic
and steric behavior, on the catalytic activity of the resulting arene-ruthenium-aniline complexes.
Time-scaled NMR and mass spectral investigation were also performed to monitor the reaction
progress and to identify the reactive intermediate species formed during the C-H bond activation
reactions.[5g][15a][16] All the synthesized arene-ruthenium complexes was well characterized using
spectro-analytical techniques and structural identity of few of the representative complexes was
established by single crystal X-ray diffraction also.
Results and Discussion
Synthesis and structure of water soluble arene-ruthenium-aniline based complexes
We have previously demonstrated that aniline ligands, with varying steric and electronic
properties ((L = aniline (L1), 2-methylaniline (L2), 2,6-dimethylaniline (L3), 4-methylaniline
4
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
(L4), 4-chloroaniline (L5)), reacts readily with arene-ruthenium precursors to synthesize water
[15a,17]
soluble arene-ruthenium-aniline based complexes.
Therefore, [(η6-(p-cymene)Ru(L)Cl2)]
(L = L1 ([Ru]-1), L2 ([Ru]-2), L3 ([Ru]-3), L4 ([Ru]-4), L5 ([Ru]-5)) are obtained in excellent
yields by reacting [{(η6(p-cymene)RuCl2}2] with aniline based ligands (L1L5) in methanol
under refluxing condition (Figure 1).
Figure 1. Schematic representation of arene-Ru(II) complexes [Ru]-1 – [Ru]-10 and the single crystal X-
ray structures of the representative complexes [Ru]-1, [Ru]-4 and [Ru]-5 assessed for the catalytic C-H
bond activation reaction. (30% thermal ellipsoids; hydrogen atoms (except those on nitrogen atoms) are
omitted for clarity)
1
13
Structural identity of complexes [Ru]-1[Ru]-5 was confirmed by H NMR, C NMR
and ESI mass spectrometry. As reported earlier, analogous [(η6-benzene)Ru(L)Cl2)] ((L = L1
([Ru]-6), L2 ([Ru]-7), L3 ([Ru]-8), L4 ([Ru]-9) and L5 ([Ru]-10)) were also synthesized.[15a,17]
As expected all the complexes showed a downfield shift for the protons of aniline ligands in
5
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
comparison to the free ligand, suggesting the coordination of aniline ligands with the ruthenium
metal. Moreover, 1H NMR resonances for protons corresponding to ruthenium coordinated η6-(p-
cymene) ring were also observed in the expected region, further supports the proposed structural
formulation of these complexes. Stability of the catalysts [Ru]-1−[Ru]-5 were performed by
thermal gravimetric analysis (TGA) experiments. TGA results inferred that all of the catalysts
exhibit good thermal stability up to ca. 160 °C (Figure S2, see the Supporting Information).
Moreover, all the catalysts ([Ru]-1 to [Ru]-10) are air stable and no decomposition or structural
change of these catalysts have been observed on exposure to air.
Single crystals of complexes [Ru]-1, [Ru]-4 and [Ru]-5 were grown by the slow evaporation of
a methanol-dichloromethane solution of the respective complexes and their molecular structures
were confirmed by single-crystal X-ray diffraction studies. The molecular structure of the
complex [Ru]-2 was also confirmed by single-crystal X-ray diffraction studies (Figure S1, see
the Supporting Information), but unfortunately, diffraction data was weak and therefore complete
data refinement could not be retrieved. Nevertheless, based on the obtained un-refined X-ray
data, there is a clear information about the coordination of 2-methylaniline to the ruthenium
centre (Figure S1, see the Supporting Information). As shown in Figure 1, all the complexes,
[Ru]-1, [Ru]-4 and [Ru]-5, adapted the pseudo-octahedral geometry where η6-p-cymene ring
occupied the top position and the aniline ligand along with two chloro groups occupied the three
legs respectively. Complex [Ru]-1 crystallizes in the triclinic crystal system with P1ˉ space
group, whereas complexes [Ru]-4 and [Ru]-5 attain the monoclinic crystal system with P21/n
space group. In agreement with the proposed formulation shown in Figure 1, molecular
structures confirmed the co-ordination of aniline ligands (L1, L4 and L5) through the nitrogen
atom to the ruthenium centre.[15a][17] Interestingly, the Ru-N distance is slightly shorter
(2.1632(19) Å) for electronically rich 4-methylaniline containing complex [Ru]-4, than those for
6
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
complexes [Ru]-5 (2.178(2) Å) and [Ru]-1 (2.180(3) Å) containing 4-chloroaniline and aniline,
respectively. Phenyl ring of aniline ligands are placed away from the metal centre, as depicted
from the Ru-N-C angles of 120.5°–122.0° for complexes [Ru]-1, [Ru]-4 and [Ru]-5.[15a][17]
Angles between the legs, Cl-Ru-Cl (87.7°–89.0º) and Cl-Ru-N (80.1°–83.7°) and those between
the legs and the centroid of η6-(p-cymene ring) (127.4°–132.4°) are also in good agreement with
earlier reported analogous complexes. [15a][17][18] η6-(p-cymene) ring is displaced at a distance of
1.65 Å from the ruthenium center. Ru-Cl bond distances are in the range of 2.163–2.180 and
2.406–2.421 Å, and are comparable to those for analogous η6-benzene complexes.[15a][17]
Selected bond parameters for complexes [Ru]-1, [Ru]-4 and [Ru]-5 are provided in Table 1.
Table 1. Selected bond distances (Å) and bond angles (°) for complexes [Ru]-1, [Ru]-4 and [Ru]-5.
[Ru]-1
2.180(3)
2.406(9)
2.178
[Ru]-4
2.163(19)
2.418(6)
2.174
[Ru]-5
2.178(2)
2.424(7)
2.174
Ru1-N1
Ru1-Cl
Ru1-Cav
Ru1-Ct
1.658
1.652
1.652
Cl1-Ru1-N1
Cl2-Ru1-N1
Cl1-Ru1-Cl2
Ru1-N1-C1
83.74(9)
80.23(8)
87.76(3)
120.5(2)
82.61(6)
80.15(5)
89.01(2)
122.08(13)
82.94(6)
80.34(6)
89.09(3)
120.77(17)
Catalytic ortho-C-H bond arylation of 2-phenylpyridine with arylchlorides
At the outset of our investigations towards C-H bond activation reactions, the catalytic reaction
was performed using 2-phenylpyridine (1a) and 4-chloroanisole (2a, as arylation agent) in the
presence of [Ru]-1 (5 mol%) in water at 80 ºC. Results as summarized in Table 2, inferred that
monoarylated product (3a) by ortho-C-H arylation of 2-phenylpyridine (1a) was formed as the
major product (88%), along with diarylated product (4a) as minor component (12%). Preliminary
7
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
results suggested that (η6-p-cymene)Ru complex ([Ru]-1) showed higher selectivity for
monoarylated product (3a) than the (η6-benzene)Ru complex ([Ru]-6) (Table 2, entries 1 and 2).
Table 2. Catalytic ortho-C-H bond arylation of 2-phenylpyridine with 4-chloroanisole in water[a][b]
Sel. [%]
(3a/4a)
TON/
Entry
Catalyst
Conv. [%]
TOF [h-1]
1
2
[(η6(p-cymene)RuCl2(aniline)] ([Ru]-1)
[(η6(benzene)RuCl2(aniline)] ([Ru]-6)
[(η6-p-cymene)RuCl2(2,6-dimethylaniline)] ([Ru]-3)
[(η6-p-cymene)RuCl2(4-methylaniline)] ([Ru]-4)
[(η6-p-cymene)RuCl2(4-chloroaniline)] ([Ru]-5)
[{(η6(p-cymene)RuCl2}2]
94
96
88/12
86/14
92/8
18.8/4.7
19.2/4.8
17/4.2
3
85
4
>99
89
93/7
20/5
5
90/10
89/11
96/4
17.8/4.4
18/4.5
6
7[c]
90
[(η6-p-cymene)]RuCl2(PPh3)]
88
17.6/2.2
[a] Reaction Conditions: 1a (0.6 mmol), 2a (0.5 mmol), K2CO3 (3 equiv.), [Ru] catalyst (5 mol%) in water
(2 mL) at 80 ºC for 4 h. [b] Conversion and selectivity were determined by 1H NMR. [c] 8 h.[9]
Figure 2. Comparative catalytic efficacy (as TOF h-1) of various (6-p-cymene)ruthenium complexes for
ortho-C-H bond arylation of 2-phenylpyridine (1a) with 4-chloroanisole (2a) at 80 ºC in water.
8
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
To further investigate the effect of various aniline ligands (L1, L3, L4 and L5) having
different steric and electronic properties on the C-H bond activation of 2-phenylpyridine,
catalytic reactions were performed with complexes [Ru]-1 to [Ru]-5 under the optimized
reaction conditions (Table 2 and Figure 2). Results inferred that having sterically bulky 2,6-
dimethylaniline ligand, [Ru]-3 displayed lower conversion (85%) in 4 h as compared to [Ru]-1
complex containing aniline ligand (94%) (Table 2, entries 1 and 3). Interestingly, amongst all the
ruthenium complexes investigated, [Ru]-4 having 4-methyl aniline ligand outperform with
complete C-H bond arylation of 2-phenlpyridine (1a) achieved in 4 h with 93% selectivity for
ortho-C-H bond activated monoarylated product, 3a (Table 2, entry 4). Contrary to the above,
[Ru]-5 having 4-chloroaniline ligand also showed lower conversion (90%) (Table 2, entry 5).
Notably, under analogous reaction conditions, the precursor (arene)Ru dimer, [{(η6-p-
cymene)RuCl2}2] also showed lower conversion (90%). It is worth mentioning that the structural
analogue of [(η6-p-cymene)RuCl2(4-methylaniline)] ([Ru]-4), the phosphine containing complex
[(η6-p-cymene)]RuCl2(PPh3)] was reported to display only 88% conversion towards C-H bond
arylation of 2-phenylpyridine under analogous reaction conditions.[9] Figure 2 displayed the
comparative TOF (h-1) of the arene-ruthenium complexes studied towards the C-H bond
activation of 2-phenylpyridine. Further, the presence of inert atmosphere was found to be crucial
to achieve high catalytic conversions, as no reaction was occurred in the absence of inert
atmosphere. Notably, analogous to argon atmosphere, nitrogen atmosphere also worked well to
achieve comparable catalytic conversions (Table S5, see the Supporting Information). Further, it
is important to mention that the catalytic reactions performed using [{(η6-(p-cymene)RuCl2}2]
with aniline ligands (L1/L4/L5) added, resulted in lower activity, suggesting that the presence of
a pre-formed structure of ruthenium coordinated aniline ligand structure is crucial to achieve
higher catalytic activity (Table S6, see the Supporting Information).
9
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
Figure 3. Influence of ligands on the reaction progress for the catalytic ortho-C-H bond arylation of 2-
phenylpyridine with 4-chloroanisole over complexes [Ru]-3, [Ru]-4 and [Ru]-5.
Time-scaled 1H NMR experiments were performed over a period of 28 h, to understand
the effect of different substituents of aniline based ligands on the catalytic reaction. As inferred
from the Figure 3, [Ru]-4 was found to be highly active among all the complexes studied, as
with [Ru]-4 complete conversion can be achieved in 4 h. Notably, [Ru]-4 was found to exhibit
the higher rate (3.22 × 10-4 sec-1) for the initial 4 h of reaction (Figure S3, see the Supporting
Information). Contrary to [Ru]-4, complexes having bulky 2,6-dimethyl aniline ([Ru]-3) and the
4-chloroaniline complex, [Ru]-5, showed relatively lower activity (1.60 × 10-4 sec-1 and 1.86 ×
10-4 sec-1, respectively for [Ru]-3 and [Ru]-5) under analogous reaction conditions (Figure S3,
see the Supporting Information). The observed results suggesting a crucial role of aniline ligands
to achieve high catalytic activity towards C-H bond activation/arylation reaction. Further
exploration using a wide range of arylchlorides for the ortho-C-H bond arylation of 2-
phenylpyridine was conducted over the highly active [Ru]-4 complex at 80 ºC in water.
10
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
A wide range of arylchlorides having electron donating and electron withdrawing
substituents were used for the C-H bond arylation of 2-phenylpyridine. Results are summarized
in Table 3. Notably, the monoarylated product was found to be the major product for most of the
arylchlorides used. Chlorobenzene (2b), which is considered as most inactive arylhalide due to
lack of any substitution, gave complete conversion in 8 h with 87% selectivity for the
monoarylated product (3b) (Table 3, entry 2). Similar to 4-chloroanisole (2a), electron donating
substituted arylchlorides, such as 4-chlorotoluene (2c) and 4-bromo-N,N-dimethylaniline (2d),
also resulted in complete conversion in 4 h and 8 h, respectively to their corresponding C-H
arylated products 3c and 3d in 90% and 65% selectivities (Table 3, entries 3 and 4). Contrary to
arylchlorides with electron donating groups, those having electron withdrawing groups, such as
4-chloroacetophenone (2e) and 4-chloromethylbenzoate (2f) exhibited moderate activities
towards C-H arylation with 45% (6 h) and 92% (8 h) conversion respectively to obtain (3e) and
(3f) in 53% and 87% selectivities respectively (Table 3, entries 5 and 6). (Hetero)arylchlorides
such as 2-chlorothiophene (2g) and 5-methyl 2-chlorothiophene (2h) were also used for ortho-C-
H bond arylation of 2-phenylpyridine, where high conversion was achieved towards respective
C-H arylated products (3g) and (3h) in 82% and 80% selectivities, respectively (Table 3, entries
7 and 8). Analogous thiophene containing poly(hetero)aryls (3h) may also be prepared by double
C-H activation using rhodium or ruthenium catalysts.[6e] However, the reaction performed with
2-bromopyridine (2i) resulted in poor conversion (Table 3, entry 9).
11
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
Table 3. Catalytic ortho-C-H bond arylation of 2-phenylpyridine using various (hetero)arylhalides over
[Ru]-4 catalyst in water[a][b][c]
Entry
Substrate
2a
t [h] Conv. [%]
Sel. [%]
Product [Yield%]
1
8
8
4
8
6
>99
>99
>99
86
90/10
(3a:4a)
3a [60%]
2
3
4
5
87/13
(3b:4b)
2b
2c
2d
3b [45%]
90/10
(3c:4c)
3c [73%]
65/35
(3d:4d)
3d [42%]
3e [20%]
45
53/47
(3e:4e)
2e
12
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
6
8
4
8
8
92
87/13
(3f:4f)
2f
3f [58%]
3g [62%]
3h [53%]
7
8
9
>99
80
82/18
(3g:4g)
2g
80/20
(3h:4h)
2h
2i
38
79/21
(3i:4i)
3i [23%]
[a] Reaction conditions: 2-phenylpyridine (0.6 mmol), (hetero)arylhalide (0.5 mmol), K2CO3 (3 equiv.),
1
[Ru]-4 (5 mol%) in water (2 mL) at 80 ºC. [b] Conversion and selectivity were determined by H NMR.
[c] Isolated yield are given in parenthesis.
Scheme 2. Competitive C-H bond arylation of 2-phenylpyridine (1a) with 4-chloroanisole (2a) and 2-
chlorothiophene (2g) over [Ru]-4 catalyst.
Further, to compare the chemoselectivity towards C–H arylated products, competitive C-
H bond arylation reaction of 2-phenypyridine (1a) was performed using an equimolar ratio of 4-
chloroanisole (2a) and 2-chlorothiophene (2g) under the optimized reaction conditions over
13
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
complex [Ru]-4 (Scheme 2). Selectivities of different C-H arylated products were determined by
1
the H NMR. Results inferred that the formation of monoarylated product (3g, 78% selectivity)
of 2-chlorothiophene (2g) was dominated over the monoarylated product (3a, 8% selectivity) of
4-chloroanisole during the competitive arylation. Notably, biarylated product of 2-
chlorothiophene was also formed (4g, with 14% selectivity), but cross-biarylation was not
observed.
Figure 4. Mass spectral identification of cycloruthenated species for the reaction of [Ru]-4 and 2-
phenylpyridine (with 1:2 molar ratio) in water.
It is well established that ruthenium catalyzed C-H bond activation of 2-phenylpyridine is
expected to proceed via a five-membered cycloruthenated species.[12][19] In this context, our
experimental findings, including extensive mass spectral studies, inferred that the formation of
analogous cycloruthenated species during the catalytic C-H bond arylation reaction over [Ru]-4
complex. Mass spectral analysis of stoichiometric reaction of [Ru]-4 and 2-phenylpyridine (in
1:2 molar ratio) in acetonitrile with added triethylamine (Et3N) as base showed a prominent peak
appeared at m/z = 390.07 corresponding to the expected cycloruthenated species {(η6-p-
cymene)Ru(κ2-C,N-phenylpyridine)}+ ([Ru]-A) (Figure 4). As the reaction was performed in
acetonitrile, acetonitrile coordinated peak was also observed at m/z = 431.10 (Figure 4). The
14
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
observed m/z position and mass patterns are in good agreement with the calculated mass pattern
of {(η6-p-cymene)Ru(κ2-C,N-phenylpyridine)} + CH3CN (Figures S4 and S5, see the Supporting
Information). Notably, mass spectral studies of the stoichiometric reaction performed in water,
analogous to the catalytic reaction conditions, with complex [Ru]-4 and 2-phenylpyridine (1a)
(in 1:2 molar ratio) in the presence of K2CO3 (3 equiv.), also showed the formation of analogous
cycloruthenated species ([Ru]-A). Moreover, cycloruthenated species ([Ru]-A) was isolated and
characterized by 1H NMR and MS (Figures S4-S6, see the Supporting Information).[12][19] Hence
the formation of the cycloruthenated species [Ru]-A, inferred that the studied arene-ruthenium-
aniline complexes also followed the analogous reaction pathway for the C-H bond activation by
initial ortho-C-H bond activation of 2-phenylpyridine in water (Figure 4).
1H NMR studies inferred that there is a distinct influence of the substituents of the aniline
ligands on the catalytic activity of the resulting complexes. To further authenticate this, we
performed mass spectral analysis during catalytic C-H bond activation reaction (0-8 h) over
[Ru]-3, [Ru]-4 and [Ru]-5 complexes. In agreement with [Ru]-4, analogous cycloruthenated
species {(η6-p-cymene)Ru(κ2-C,N-phenylpyridine)}+ was also observed for the complex [Ru]-3
and [Ru]-5. Interestingly, the m/z intensity ratio of cyclometalated species {(η6-p-cymene)Ru(κ2-
C,N-phenylpyridine)}+ ([Ru]-A, m/z = 390.01) to the molecular ion peak of [Ru]-5 catalyst
({(η6-p-cymene)Ru(L5)Cl}+ m/z = 398.11) was found to be 7 and 22 times higher than that
observed with [Ru]-4 and [Ru]-3 complexes. Interestingly, a ligand bonded cycloruthenated
species (η6-p-cymene)Ru(L4)(κ2-C,N-phenylpyridine)}+ ([Ru]-B4) was also observed for [Ru]-4,
however an analogous species were not observed for [Ru]-3 or [Ru]-5. These findings suggested
that the removal of electron deficient 4-chloroaniline was very facile over 4-methylaniline and
2,6-dimethylaniline from their respective complex under catalytic reaction conditions.
15
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
Amongst the studied complexes, removal of sterically bulky, 2,6-dimethylaniline (L3)
ligand from [Ru]-3 was appeared to be least favorable which was further supported by the
appearance of a peak at m/z = 357.09 corresponding to {(η6-p-cymene)Ru(L3)}2+. We
anticipated that the initial interaction of 2-phenylpyridine with ruthenium catalyst led to the
formation of a short-lived intermediate {(η6-p-cymene)Ru(κ1-N-phenylpyridine)(L)}2+ ([Ru]-C)
by following step I (Scheme 3). This step is presumably least favorable for [Ru]-3 having a
sterically demanding, 2,6-dimethylaniline (L3) ligand, as mass spectral data inferred the
formation of cyclometalated species was slowest for [Ru]-3 compared to [Ru]-4 and [Ru]-5.
Further the intermediate such as, [Ru]-C undergoes facile transformation to cyclometalated
species [Ru]-A. Notably, a ligand bounded cycloruthenated species [Ru]-B may also formed via
step III as observed for [Ru]-4 (Scheme 3). Thus, electronic and steric behavior of the
coordinating aniline ligands exerts crucial role to tune the catalytic activity of the studied arene-
ruthenium-aniline based complexes towards C-H bond activation/arylation of 2-phenylpyridine
with arylhalides. It is worthy to mention that the Ru-aniline ligand bonds in the studied
complexes displayed high stability towards dissociation in heating in water. As inferred from the
mass spectral analysis, peaks corresponding of the complexes with added solvent molecules,
water and/or methanol (as methanol was used for the dilution of the solution) were only observed
with no sign of the dissociation of Ru-aniline bond.
16
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
Scheme 3. Mass spectral investigation of the formation of cyclometalated species during the ortho-C-H
bond activation.
Notably, reaction of the isolated [Ru]-A species with 4-chloroanisole under the optimized
reaction conditions afforded the formation of C-H arylated products (3a and 3b) with 49%
conversion. Consistent with earlier reports, these results also inferred that the cycloruthenated
species [Ru]-A is indeed the active species participating in the C-H arylation reaction.
[9b][12][19][21]
On the basis of experimental and extensive mass spectral investigations a plausible
reaction mechanism of ortho-C-H bond arylation of 2-phenylpyridine is elaborated in Scheme 4.
17
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
Scheme 4. Plausible mechanism of ortho-C-H bond arylation of 2-phenylpyridine with
(hetero)arylhalides.
Conclusions
We developed a new class of phosphine-free water-soluble arene-ruthenium complexes obtained
with readily available aniline based ligands, and successfully employed these complexes for the
ortho-C-H bond activation and arylation of 2-phenylpyridine with a wide range of
(hetero)arylhalides in water. Results inferred that monoarylated products were preferred over
biarylated products, where moderate to good yields of the corresponding monoarylated products
were achieved. Time-scaled NMR and mass spectral investigation evidenced that aniline ligands,
of varying electronic and steric behavior, exerts significant influence on the observed catalytic
activity. Moreover, NMR and mass spectral identification of several cycloruthenated species,
including those with ligand coordinated cycloruthenated species, further authenticated the crucial
role of these species in the catalytic C-H bond activation reaction. Moreover, after spectro-
analytical characterization, structural identity of some representative complexes was further
confirmed by single crystal X-ray diffraction studies. We believe the findings of the present
18
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
work will significantly contribute towards the investigation and development of highly active
phosphine-free and water-soluble new catalytic systems for C-H bond activation and
functionalization reactions. Further investigations in this direction are underway.
Experimental Section
General process for the synthesis of arene-ruthenium-aniline complexes ([Ru]-1 ‒ [Ru]-5)
Dichloro bridged arene-ruthenium precursors [{(η6-C10H14)RuCl2}2] (0.5 mmol) and the suitable
aniline based ligand (1.05 mmol) in methanol (100 mL) were refluxed for 24 h.[15a][17] The
resulting solution was filtered and solvent was removed under reduced pressure. Resulting
1
complexes were characterized using H NMR, 13C NMR, ESI-Mass spectrometry, CHN
elemental analysis and single crystal X-ray diffraction studies.
General process for C-H bond activation/ arylation reactions
In a two necked reaction flask containing 2-phenylpyridine (0.6 mmol, 86 µL), K2CO3 (3 equiv.,
1.5 mmol, 0.207 g) and 5 mol % Ru catalysts in 2 mL water, was added 0.5 mmol of
arylchloride. Reaction mixture was further degassed using a vacuum pump and then filled with
Argon. Reaction mixture was stirred at 80 ºC for the specified reaction time under Argon, after
completion of the reaction, it was cooled to room temperature. Crude reaction mixture was
extracted with ethylacetate (3 × 10 mL) and dried over Na2SO4. The obtained solid, after
1
removal of solvent under vacuum, was further analyzed by H NMR. Products were further
separated and purified by column chromatography (ethylacetate/ hexane 99:1, v/v).
Typical process for the competitive C-H bond arylation reaction
In a two necked reaction flask containing 2-phenylpyridine (0.6 mmol, 86 µL), K2CO3 (3 equiv.)
and 5 mol % [Ru]-4 catalyst in 2 mL water, was added 0.5 mmol each of 4-chloroanisole (61
19
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
µL) and 2-chlorothiophene (49 µL). Reaction mixture was further degassed with vacuum pump,
and then filled with Argon. Reaction mixture was stirred at 80 ºC for 8 h under Argon, and after
the specified reaction time, reaction mixture was cooled to room temperature. Crude reaction
mixture was extracted with ethylacetate (3 × 10 mL) and dried over Na2SO4. The obtained solid,
after removal of solvent under vacuum, was further analyzed by 1H NMR.
Typical stoichiometric reaction for the identification of cycloruthenated species
[Ru]-4 (0.03 mmol, 0.0123 g) and 2-phenylpyridine (0.06 mmol, 8.6 µL) in 5 mL acetonitrile
were taken in a reaction flask, which was added 2 µL of Et3N (triethylamine). Reaction flask was
degassed with vacuum pump and then filled up with Argon. Reaction mixture was then stirred at
80 ºC for 3 h, and then was cooled to room temperature. Crude reaction mixture was diluted with
acetonitrile and analyzed by ESI-MS in positive mode. For reaction performed in water,
potassium carbonate (1.5 mmol, 0.207 g) was used instead of triethylamine.
Time-scaled mass spectrometric analysis of the cycloruthenated species
Reaction flask containing [Ru]-4 (0.025 mmol, 0.0103 g) in 2 mL water was added 2-
phenylpyridine (0.6 mmol, 86 µL) and 4-chloroanisole (0.5 mmol, 61 µL). Reaction mixture was
heated at 80 ºC under Argon for 8 h. 100 µL of aliquot from the reaction mixture was taken out
at different intervals of reaction time (2, 4, 6 and 8 h), which was diluted with acetonitrile and
ESI-MS was recorded in positive mode. Analogous reactions were also performed using [Ru]-1,
[Ru]-3 and [Ru]-5 complexes.
Single crystal X-ray diffraction structure determination
Single crystal X-ray diffraction structural studies of the complexes [Ru]-1, [Ru]-2, [Ru]-4 and
[Ru]-5, from the suitably grown crystals of the complexes by the slow evaporation of methanol-
20
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
dichloromethane solution of the respective complexes, were carried out using Agilent
Technologies Supernova CCD system. Using graphite-monochromated CuKα radiation (λ =
1.54184 Å) based diffraction, data were collected by the standard ‘phi-omega’ scan techniques
and were scaled and reduced using CrysAlisPro RED software. The extracted data was evaluated
using the CrysAlisPro CCD software. Structures were solved by direct methods using SHELXS-
97 and refined by full matrix least-squares with SHELXL-97, refining on F2.[20] The positions of
all the atoms were determined by direct methods. All non-hydrogen atoms were refined
anisotropically. The remaining hydrogen atoms were placed in geometrically constrained
positions, and refined with isotropic temperature factors, generally 1.2Ueq of their parent atoms.
Unfortunately, X-ray diffraction data for complex [Ru]-2 was found to be abnormal and could
not be further refined to obtain suitable parameters to report. Crystallographic data and bond
parameters for the complexes [Ru]-1, [Ru]-4 and [Ru]-5 are listed in Table 4 and Table S1-S4
(see the Supporting Information). CCDC deposition numbers of the complexes [Ru]-1, [Ru]-4
and [Ru]-5 are 1491603, 1491612 and 1491613, respectively.
Table 4. Crystal data and structure refinement for complex [Ru]-1, complex [Ru]-4 and complex [Ru]-5
crystal parameter
Empirical formula
Formula weight
Temperature (K)
Wavelength (Å)
complex [Ru]-1
C16H21Cl2N Ru
399.31
complex [Ru]-4
C17H23Cl2 N Ru
413.33
complex [Ru]-5
C16 H20Cl3N Ru
433.75
150 (2)
150 (2)
293(2)
1.54184
1.54184
0.71073
Crystal system, space
group
Triclinic, P1ˉ
Monoclinic, P21/n
Monoclinic, P21/n
a (Å)
b (Å)
c (Å)
α (ᵒ)
7.9112 (5)
9.0981 (8)
12.6300 (12)
87.499 (7)
85.297 (6)
69.365 (7)
8.9820 (10)
12.4077 (14)
15.6385 (18)
90
8.8940 (4)
12.4578 (4)
15.5966 (6)
90
β (ᵒ)
90.80
91.468 (3)
90
γ (ᵒ)
90
21
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
Volume (Å3)
847.78(12)
2, 1.564
1742.7(3)
4, 1.575
1727.53 (12)
Z, calculated density
(mg/m3)
4, 1.668
µ (mm-1)
10.287
10.030
1.364
F (000)
404
840
872
Crystal size (mm3)
0.33 × 0.26 × 0.21
5.20 to 71.40
0.28 × 0.24 × 0.22
5.65 to 71.51
0.23 × 0.18 × 0.13
3.07 to 32.23
Theta range for data
collection (°)
Index ranges
-9<=h<=7;
6<=h<=10;
-14<=k<=15;
-19<=l<=18
-12<=h<=11
-18<=k<=17
-22<=l<=22
-11<=k<=11;
-15<=l<=14
Reflections collected
5180 / 3182
10688 / 3348
20254 / 5745
[R(int) = 0.0373]
[R(int) = 0.0204]
[R(int) = 0.0503]
Completeness to theta
(%)
96.4 (θ = 71.40°)
98.8 (θ = 71.51°)
99.8 (θ = 25.24°)
Absorption correction
Semi-empirical from
equivalents
Semi-empirical from
equivalents
Semi-empirical from
equivalents
Max. and min.
transmission
1.00000 and 0.29294
0.2163 and 0.1656
1.00000 and 0.82150
Refinement method
Full-matrix least-
squares on F^2
Full-matrix least-
squares on F^2
Full-matrix least-
squares on F^2
Data/ restraints/
parameters
3182 / 0 / 184
3348 / 0 / 194
5745 / 0 / 193
Goodness-of-fit on F2
1.062
1.059
1.084
Final R indices [I >
2sigma(I)]
R1 = 0.0443,
wR2 = 0.1208
R1 = 0.0271,
wR2 = 0.0743
R1 = 0.0417
wR2 = 0.0951
R indices (all data)
R1 = 0.0449,
wR2 = 0.1222
R1 = 0.0275,
wR2 = 0.0747
R1 = 0.0557
wR2 = 0.1033
Largest diff. peak and
hole (eÅ-3)
1.130 and -1.692
0.592 and -1.012
1.168 and -0.997
Acknowledgements
Authors thank IIT Indore, SERB (DST), New Delhi (SB/FT/CS-028/2014) and CSIR, New Delhi
(01(2722)/13/EMR-II) for financial support. Authors also thank SIC, IIT Indore for instrumental
facility. C.B. thanks MHRD, Govt. of India, for her fellowship. D.T. and R.K.R. thank UGC,
New Delhi and CSIR, New Delhi respectively for their SRF grants.
22
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
References
[1]
(a) A. E. Shilov, G. B. Shul'pin, Chem. Rev. 1997, 97, 2879-2932; (b) C. Jia, T.
Kitamura,Y. Fujiwara, Acc. Chem. Res. 2001, 34, 633-639; (c) V. Ritleng, C. Sirlin, M.
Pfeffer, Chem. Rev. 2002, 102, 1731–1770; (d) J. A. Labinger, J. E. Bercaw, Nature
2002, 417, 507-514; (e) I. A. I. Mkhalid, J. H. Barnard, T. B. Marder, J. M. Murphy, J. F.
Hartwig, Chem. Rev. 2010, 110, 890-931; (f) A. Gunay, K. H. Theopold, Chem. Rev.
2010, 110, 1060-1081; (g) B. Li, P. H. Dixneuf, Chem. Soc. Rev. 2013, 42, 5744-5767;
(h) S. D. Sarkar, W. Liu, S. I. Kozhushkov, L. Ackermann, Adv. Synth. Catal. 2014, 356,
1461-1479; (i) G.-F. Zha, H.-I. Qin, E. A. B. Knatchev, RSC Adv. 2016, 6, 30875-30885;
(j) S. Kozhushkov, H. K. Potukuchi, L. Ackermann, Catal. Sci. Technol. 2013, 3, 526-
571; (k) D. Balcells, E. Clot, O. Eisenstein, Chem. Rev. 2010, 110, 749-823; (l) M.
Moselage, J. Li, L. Ackermann, L. ACS Catal. 2016, 6, 498-525.
[2]
(a) L. C. Campeau, K. Fagnou, Chem. Commun. 2006, 1253-1264; (b) X. Chen, K. M.
Engle, D. H. Wang, J. Q. Yu, Angew. Chem., Int. Ed. 2009, 48, 5094-5115; (c) T. W.
Lyons, M. S. Sanford, Chem. Rev. 2010, 110, 1147-1169; (d) E. M. Beck, M. J. Gaunt,
Top. Curr. Chem. 2010, 292, 85-121; (e) C. L. Sun, B. Li, Z. J. Shi, Chem. Commun.
2010, 46, 677-685.
[3]
[4]
(a) A. N. Vedernikov, Curr. Org. Chem. 2007, 11, 1401-1416; (b) J. Albert, R. Bosque,
M. Crespo, J. Granell, J. Rodríguez, J. Zafrillaj, Organometallics 2010, 29, 4619-4627;
(c) S. Fantasia, A. Pasini, S. P. Nolan, Dalton Trans. 2009, 8107-8110.
(a) J. Tenn, K. J. H. Young, G. Bhalla, J. Oxagaard, W. A. Goddard, R. A. Perriana, J.
Am. Chem. Soc. 2005, 127, 14172-14173; (b) T. Mita, Y. Ikeda, K. Michigami, Y. Sato,
Chem. Commun. 2013, 49, 5601-5603; (c) D. A. Frasco, C. P. Lilly, P. D. Boyle, E. A.
Ison, ACS Catal. 2013, 3, 2421-2429; (d) T. Shibata, N. Ryu, H. Takano, Adv. Synth.
23
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
Catal. 2015, 357, 1131-1135; (e) P. Gao, W. Guo, J. Xue, Y. Zhao, Y. Yuan, Y. Xia, Z.
Shi, J. Am. Chem. Soc. 2015, 137, 12231-1224; (f) M. A. Bowring, R. G. Bergman, T. D.
Tilley, J. Am. Chem. Soc. 2013, 135, 13121-13128.
[5]
(a) S. Burling, M. F. Mahon, B. M. Paine, M. K. Whittlesey, J. M. J. Williams,
Organometallics 2004, 23, 4537-4539; (b) L. Ackermann, A. Althammer, R. Born, Syn.
Lett. 2007, 18, 2833-2836; (c) D. Giunta, M. Hölscher, C. W. Lehmann, R. Mynott, C.
Wirtz, W. Leitner, Adv. Synth. Catal. 2003, 345, 1139-1145; (d) C. Flender, A. M.
Adams, J. L. Roizen, E. McNeill, J. D. Bois, R. N. Zare, R. N. Chem. Sci. 2014, 5, 3309-
3314; (e) S. I. Kozhushkov, Ackermann, L. Chem. Sci. 2013, 4, 886-896; (f) L.
Ackermann, A. Althammer, R. Born, Tetrahedron 2008, 64, 6115-6124; (g) L. A. Adrio,
J. Gimeno, C. Vicent, Chem. Commun. 2013, 49, 8320-8322.
[6]
(a) P. B. Arockiam, C. Bruneau, P. H. Dixneuf, Chem. Rev. 2012, 112, 5879-5918; (b) L.
Ackermann, P. Novak, R. Vicente, N. Hofmann, Angew. Chem., Int. Ed. 2009, 48, 6045-
6048; (c) L. Ackermann, Acc. Chem. Res. 2014, 47, 281-295; (d) K. Padala, M.
Jeganmohan, Org. Lett. 2011, 13, 6144-6147; (e) J. Dong, Z. Long, F. Song, N. Wu, Q.
Guo, J. Lan, J. You, Angew. Chem., Int. Ed. 2013, 52, 580-584; (f) L. Ackermann, R.
Vicente, Top. Curr. Chem. 2010, 292, 211-229; (g) R. Manikandan, M. Jeganmohan,
Org. Biomol. Chem. 2015, 13, 10420-10436.
[7]
(a) S. Oi, S. Fukita, N. Hirata, N. Watanuki, S. Miyano, Y. Inofue, Org. Lett. 2001, 3,
2579-2581; (b) L. Ackermann, M. Mulzer, Org. Lett. 2008, 10, 5043-5045; (c) B. R. Yu,
X. Y. Yan, S. Wang, N. Tang, C. J. Xi, Organometallics 2010, 29, 3222-3226; (d) L.
Ackermann, R. Born, Angew. Chem., Int. Ed. 2006, 45, 2619-2622; (e) D. Zell, S.
Warratz, D. Gelman, S. J. Garden, L. Ackermann, Chem. Eur. J. 2016, 22, 1248-1252.
24
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
[8]
[9]
(a) L. Ackermann, R. Born, R. Vicente, ChemSusChem 2009, 2, 546-549; (b) L.
Ackermann, R. Vicente, A. Althammer, Org. Lett. 2008, 10, 2299-2302; (c) L.
Ackermann, Org. Lett. 2005, 7, 3123-3125.
(a) P. B. Arockiam, C. Fischmeister, C. Bruneau, P. H. Dixneuf, Green Chem. 2013, 15,
67-71; (b) E. F. Flegeau, C. Bruneau, P. H. Dixneuf, A. Jutand, J. Am. Chem. Soc. 2011,
133, 10161-10170; (c) P. B. Arockiam, C. Fischmeister, C. Bruneau, P. H. Dixneuf,
Angew. Chem., Int. Ed. 2010, 49, 6629-6632.
[10] (a) I. Fabre, N. V. Wolff, G. L. Duc, E. F. Flegeau, C. Bruneau, P. H. Dixneuf, A. Jutand,
Chem. Eur. J. 2013, 19, 7595-7604; (b) J. Hubrich, T. Himmler, L. Rodefeld, L.
Ackermann, ACS Catal. 2015, 5, 4089-4093; (c) Li, J. Ackermann, L. Org. Chem. Front.
2015, 2, 1035-1039; (d) L. Ackermann, P. Novák, Org. Lett. 2009, 11, 4966-4969; (e) L.
Ackermann, R. Jeyachandran, H. K. Potukuchi, P. Novák, L. Büttner, Org. Lett. 2010,
12, 2056-2059; (f) J. Hubrich, L. Ackermann, Eur. J. Org. Chem. 2016, DOI:
10.1002/ejoc.201600742.
[11] (a) W. B. Li, P. B. Arockiam, C. Fischmeister, C. Bruneau, P. H. Dixneuf, Green Chem.
2011, 13, 2315-2319.
[12] (a) A. D. Dwivedi, C. Binnani, D. Tyagi, K. S. Rawat, P.-Z. Li, Y. Zhao, S. M. Mobin,
B. Pathak, S. K. Singh, Inorg. Chem. 2016, 55, 6739-6749; (b) L. Ackermann, A. V.
Lygin, Org. Lett. 2011, 13, 3332-3335; (c) B. Stefane, J. Fabris, F. Pozgan, Eur. J. Org.
Chem. 2011, 3474-3481; (d) L. Ackermann, R. Vicente, H. K. Potukuchi, V. Pirovano,
Org. Lett. 2010, 12, 5032-5035.
[13] K. S. Singh, P. H. Dixneuf, ChemCatChem 2013, 5, 1313-1316.
[14] I. O’zdemir, S. Demir, B. Cetinkaya, C. Gourlaouen, F. Maseras, C. Bruneau, P. H.
Dixneuf, J. Am. Chem. Soc. 2008, 130, 1156-1157.
25
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
[15] (a) D. Tyagi, C. Binnani, R. K. Rai, A. D. Dwivedi, K. Gupta, P. Z. Li,Y. Zhao, S. K.
Singh, Inorg. Chem. 2016, 55, 6332-6343; (b) E. J. Farrington, C. F. J. Barnard, E.
Rowsell, J. M. Brown, Adv. Synth. Catal. 2005, 347, 185-195.
[16] D. Schröder, Acc. Chem. Res. 2012, 45, 1521-1532.
[17] D. Tyagi, R. K. Rai, A. D. Dwivedi, S. M. Mobin, S. K. Singh, Inorg. Chem. Front.
2015, 2, 116-124.
[18] (a) S. K. Singh, M. Trivedi, M. Chandra, A. N. Sahay, D. S. Pandey, Inorg. Chem. 2004,
43, 8600-8608; (b) W.-H. Kwok, G. Lu, C. E. F. Rickard, W. R. Roper, L. Wright, J.
Organomet. Chem. 2004, 689, 2511-2522; (c) R. Manikandan, G. R. Prakash, R.
Kathirvel, P. Viswanathamurthi, Spectrochim. Acta, Part A 2013, 116, 501-508.
[19] (a) Y. Boutadla, O. Al-Duaij, D. L. Davies, G. A. Griffith, K. Singh, Organometallics
2009, 28, 433-440. (b) B. Li, C. Darcel, P. H. Dixneuf, ChemCatChem 2014, 6, 127-130.
[20] G. M. Sheldrick, Acta Crystallogr., Sect. A 2008, 64, 112-122.
[21] P. Marcé, A. J. Paterson, M. F. Mahona, C. G. Frost, Catal. Sci. Technol. 2016, DOI:
10.1039/c6cy10254j.
26
This article is protected by copyright. All rights reserved

Chemistry - An Asian Journal
10.1002/asia.201600954
Graphical Abstract
Water-soluble arene-ruthenium complexes coordinated with readily available aniline based
ligands were successfully employed to achieve high catalytic activity towards C-H bond
activation and arylation of 2-phenylpyridine with a wide range of (hetero)arylhalides to afford
the corresponding ortho- monoarylated products as major products in moderate to good yields
(upto 73%). Experimental evidences, including time-scaled NMR and mass spectral
identification of the cycloruthenated species, inferred a significant effect of the electronic and
steric behavior of coordinating aniline based ligands on the catalytic activity.
27
This article is protected by copyright. All rights reserved