Catalytic hydrogenation of carbonyl and nitro compounds using an [: N, O] -chelate half-sandwich ruthenium catalyst

Article abstract of DOI:10.1039/c8dt02677g

A series of N,O-chelate half-sandwich ruthenium complexes for both carbonyl and nitro compound hydrogenation have been synthesized based on β-ketoamino ligands. All complexes exhibited high activity for the catalytic hydrogenation of a series of ketones and nitroarenes with molecular H₂ as the reducing reagent in aqueous medium. Consequently, the catalytic system showed the catalytic TON values of 950 for 1-phenylethanol in acetophenone hydrogenation and 1960 for 1-chloro-4-nitrobenzene in p-chloroaniline hydrogenation. Good catalytic activity was displayed for various kinds of substrates with either electron-donating or electron-withdrawing groups. The neutral ruthenium complexes 1-4 were fully characterized using NMR, IR, and elemental analysis. Molecular structures of complexes 2 and 4 were further confirmed using single-crystal X-ray diffraction analysis.

Full text of DOI:10.1039/c8dt02677g

View Article Online
View Journal
Dalton
Transactions
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: Z. Yao, J. Zhu, N.
Lin, X. Qiao and W. Deng, Dalton Trans., 2018, DOI: 10.1039/C8DT02677G.
This is an Accepted Manuscript, which has been through the
Volume 45 Number
1 7 January 2016 Pages 1–398
Royal Society of Chemistry peer review process and has been
accepted for publication.
Dalton
Transactions
Accepted Manuscripts are published online shortly after
An international journal of inorganic chemistry
www.rsc.org/dalton
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. We will replace this Accepted Manuscript with the edited
and formatted Advance Article as soon as it is available.
You can find more information about Accepted Manuscripts in the
author guidelines.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the ethical guidelines, outlined
in our author and reviewer resource centre, still apply. In no
event shall the Royal Society of Chemistry be held responsible
for any errors or omissions in this Accepted Manuscript or any
consequences arising from the use of any information it contains.
ISSN 1477-9226
PAPER
Joseph T. Hupp, Omar K. Farha et al.
Efficient extraction of sulfate from water using
framework
a Zr-metal–organic
rsc.li/dalton

Page 1 of 24
Dalton Transactions
View Article Online
DOI: 10.1039/C8DT02677G
Catalytic Hydrogenation of Carbonyl and Nitro Compounds Using
[NO]ꢀchelate HalfꢀSandwich Ruthenium Catalyst
ZiꢀJian Yao,a,b* JingꢀWei Zhu,a Nan Lin,a XinꢀChao Qiao,a Wei Denga*
a School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai,
201418, China.
b
State Key Laboratory of Molecular Engineering and Polymers, Shanghai Key Laboratory of
Molecular Catalysis and Innovative Material, Fudan University, Shanghai, 200433, China.
Corresponding author: Email: zjyao@sit.edu.cn; Tel: +86ꢀ21ꢀ60877231, Fax: +86ꢀ21ꢀ60873335.
Abstract: A series of N,Oꢀchelate halfꢀsandwich ruthenium complexes for both carbonyl and nitro
compounds hydrogenation have been synthesized based on βꢀketoamino ligands. All complexes
exhibited high activity for the catalytic hydrogenation of a series of ketones and nitroarenes with H2
molecular as reducing reagent in aqueous medium. Consequently, the catalytic system showed the
catalytic TON value of 950 to 1ꢀphenylethanol in acetophenone hydrogenation and 1960 to
1ꢀchloroꢀ4ꢀnitrobenzene in pꢀchloroaniline hydrogenation. Good catalytic activity was displayed for
various kinds of substrates with either electronꢀdonating or electronꢀwithdrawing groups. The
neutral ruthenium complexes 1‒4 were fully characterized by NMR, IR, and elemental analysis.
Molecular structures of complexes 2 and 4 were further confirmed by singleꢀcrystal Xꢀray
diffraction analysis.

Dalton Transactions
Page 2 of 24
View Article Online
DOI: 10.1039/C8DT02677G
Introduction
Catalytic hydrogenation of unsaturated organic substrates is one of most important research fields
of organometallic chemistry and homogeneous catalysis. Based on the prominent work of
Wilkinson, Crabtree, Knowles, Noyori and other groups, up to now, various types of highly
effective hydrogenation methodologies of unsaturated bonds (such as C=C, C=O and C=N bonds)
have been developed and widely utilized in organic synthesis, materials chemistry and
pharmaceutical industry.1 Thus the design of efficient catalysts plays a crucial role in achieving
good yields and high selectivity in these reactions. Among a number of reported catalysts,
ruthenium complexes have attracted considerable attention because of their stability and versatility.
The good stability against water of halfꢀsandwich ruthenium complexes made them ideal candidates
to perform catalytic organic transformations in aqueous solution.2 The chemical properties of the
complexes are readily modified through tuning electronic and steric effects of the ligands by
changing the substituted groups. Therefore a variety of ruthenium complexes coordinated with
NN,3,4 NO,5 NNN,6 CNN 7 type ligands have been prepared and frequently applied as catalysts.8‒10
On the other hand, halfꢀsandwich late transition metal complexes ([Cp#MCl2]2 (M = Ir, Rh, Ru),
Cp# = Cp*, pꢀcymene) show some characteristics such as good solubility, easy modification and
stability (Figure 1):11‒15 (i) the halfꢀsandwich fragments can be furnished smoothly by the reaction
of arene or cyclopentadienyl groups with metal chlorides; (ii) Cp* or substituted benzenes as η5 or
η6 ligands perfectly shield the potentially octahedral hemisphere of the metals, from which the
bonds between the metal and the donor atoms, such as Nꢀ, Sꢀ, Oꢀ, Pꢀdonor groups would benefit; (iii)
different types of substituted groups bonded to the cyclopentadienyl ring can be readily tuned the
solubility and the redox property of the corresponding complexes. These particular features made
Cp# ligands often included in the organometallic complexes.

Page 3 of 24
Dalton Transactions
View Article Online
DOI: 10.1039/C8DT02677G
Both alcohols and amines are significant building blocks for biologically active molecules and
fine chemicals in medicines, agricultural sciences, flavor industry and so on.16‒19 Reduction of
carbonyl and nitroꢀcompounds using metal catalysts in the presence of a reduction reagent is a
straightforward route to afford alcohols and amines, respectively. As mentioned above,
rutheniumꢀbased complexes often exhibited good catalytic activity in hydrogenation reactions of
unsaturated substrates.20‒22 Given the characteristics of the halfꢀsandwich fragment and the high
efficiency of the ruthenium catalysts, we are interested in exploring the synthesis and catalytic
activity of halfꢀsandwich ruthenium complexes based on different ancillary ligands. Herein, a series
of halfꢀsandwich ruthenium complexes with N, Oꢀchelated mode based on βꢀketoamino ligands
were synthesized. Preliminary results showed that these complexes exhibited good catalytic activity
in hydrogenation of both ketones and nitroꢀcompounds under proper conditions in aqueous solution.
The N, Oꢀchelate ruthenium complexes were fully characterized and the steric and electronic effects
on the catalytic activity of these complexes were also discussed.
Results and discussion
Synthesis of Halfꢀsandwich Ruthenium Complexes 1‒4. βꢀketoamino ligands L1‒L4 were
prepared by direct condensation reactions from acetylacetone and the corresponding substituted
anilines under air according to the reported procedures.23 A few drops of acetic acid were added to
the mixture to promote the reaction. All ligands were obtained in high yields as white or light
yellow solids. With the ligands in hand, the reactivity of these [NO]ꢀdonor ligands with half molar
ratio ruthenium precursor [(pꢀcymene)RuCl2]2 was investigated in the presence of sodium acetate as
base. The orangeꢀcolored turbid mixture gradually became clear red solution as the reaction went on.
As shown in Scheme 1, halfꢀsandwich ruthenium complexes 1‒4 were afforded in methanol at

Dalton Transactions
Page 4 of 24
View Article Online
DOI: 10.1039/C8DT02677G
elevated temperature in moderate isolated yields as airꢀstable solids probably because of the
formation of the sixꢀmembered chelate ring. The products are soluble in alcohol, THF and CH2Cl2,
slightly soluble in water, but are insoluble in nonꢀpolar solvents such as diethyl ether and hexane.
The βꢀketoamino ligands act as the chelate through the N, Oꢀcoordination mode in the products
which is supported by the IR and NMR spectroscopies and elemental analysis. The 1H NMR spectra
of complexes 1‒4 do not change after refluxing the halfꢀsandwich ruthenium complexes in toluene
for several hours, suggesting the thermal stability of complexes 1‒4. The TGA curves of these
o
complexes confirmed their stability at high temperature up to 300 C (see supporting information).
Complexes 1‒4 were fully characterized by various spectroscopic techniques and elemental
analysis.
Scheme 1. Synthesis of N, Oꢀchelate Halfꢀsandwich Ruthenium Complexes 1‒4
Reaction condition: 0.5 eq. [(cym)RuCl2]2, CH3OH, NaOAc, 50 oC, 6 h. Detailed description of the experiments,
see the Experimental Section.
The generation of halfꢀsandwich ruthenium products 1‒4 was supported by their 1H NMR spectra.
In comparison with the free ligand, the disappearance of one proton signal in 1‒4 from the
downfield range of δ 12.00‒13.00 ppm assigned to the hydroxyl proton confirms coordination of
the oxygen to the ruthenium centers. Additional confirmation of the N, Oꢀchelation of the ligands is
given by the chemical and magnetic inequivalence of the pꢀcymene ring protons, which appear as
1
four distinct doublets in the H NMR spectra as a consequence of the stereogenic nature of the
ruthenium center. This observation was in a good agreement with related compounds in previous

Page 5 of 24
Dalton Transactions
View Article Online
DOI: 10.1039/C8DT02677G
1
report.24 The H NMR spectra of the halfꢀsandwich complexes displayed all the expected signals.
All the ruthenium complexes show a characteristic absorption band in the range 1400‒1430 cm‒1 in
their IR spectra, which can be assigned to the vibration of the C=N bond of the ligand. These C=N
absorption band all shifted to lower frequencies when compared to those of the free βꢀketoamino
ligand (1480‒1500 cm‒1). The red shift reflected the coordination interaction between the ligand
and [(pꢀcymene)Ru] moiety. This is consistent with the increase in the electron density on the
ruthenium(II) center caused by the coordination of the C=N group, which resulted in increasing the
back bonding to the nitrogen and hence a lower C=N stretching vibration.25 The elemental analysis
and spectroscopic data of these complexes demonstrate that their structures are similar to each
other.
Crystal Structures of Halfꢀsandwich Ruthenium Complexes. To unambiguously elucidate the
structures of these N, Oꢀchelate halfꢀsandwich ruthenium complexes, an Xꢀray analysis is desired.
Single crystals suitable for Xꢀray diffraction analysis were obtained by the slow diffusion of hexane
into a saturated solution of the ruthenium complexes in dichloromethane. Both compounds 2 and 4
crystallized in the orthorhombic space group P21c (Figure 1). Selected geometric data are given in
Table 1, and their crystallographic data are summarized in the footnote of Figure 1. Both complexes
show a typical threeꢀlegged pianoꢀstool geometry with the metal center being coordinated by the
η6ꢀpꢀcymene and the N and O atoms, as well as a chloride ligand. The metal center has a
distortedꢀoctahedral environment, assuming that the η6ꢀpꢀcymene group occupies three fac
coordination sides.26 The air and thermal stability of these ruthenium complexes is presumably
caused by the formation of the sixꢀmembered ring. The distances of Ru‒N bonds in the two
complexes (2.093(2) Å (2) and 2.087(2) Å (4)) are within the range of known values for the bond in
similar ruthenium complexes.20e The Ru‒O bond lengths in complexes 2 and 4 are 2.068(2) Å and

Dalton Transactions
Page 6 of 24
View Article Online
DOI: 10.1039/C8DT02677G
2.066(3) Å, respectively, which are also consistent with previous reports.5b The sixꢀmembered ring
Ru(1)–N(1)–C(2)–C(3)–C(4)–O(1) of complex 2 is almost planar with the dihedral angle of 0.95o
between planes of N(1)–Ru(1)–O(1) and O(1)–C(4)–C(3)–C(2)–N(1), whereas the sixꢀmembered
ring in complex 4 is folded with the dihedral angle of 2.56o. The sum of the inner angles of the
sixꢀmembered ring of 719.88o further confirmed the planarity of complex 2. Nonꢀcovalent
interꢀmolecular interactions of Ru‒Cl···H(aromatic) in the crystal packing structure of the two
complexes are observed.
Figure 1. Molecular structures of 2 (a) and 4 (b) with thermal ellipsoids drawn at the 30% level. All
hydrogen atoms are omitted for clarity. Selected bond lengths (Å) and angles (deg): Complex 2:
Ru(1)–N(1), 2.093(2); Ru(1)–O(1), 2.068(2); Ru(1)–Cl(1), 2.4425(8); C(2)–N(1), 1.302(4); C(4)–
O(1), 1.285(4); O(1)–Ru(1)–N(1), 88.71(9); O(1)–Ru(1)–Cl(1), 85.01(6); Cl(1)–Ru(1)–N(1),
85.39(7); Ru(1)–O(1)–C(4), 126.48(19); Ru(1)–N(1)–C(2), 126.8(2). Complex 4: Ru(1)–N(1),
2.087(4); Ru(1)–O(1), 2.066(3); Ru(1)–Cl(1), 2.171(5); C(2)–N(1), 1.327(6); C(4)–O(1), 1.281(5);
O(1)–Ru(1)–N(1), 88.94(13); O(1)–Ru(1)–Cl(1), 84.58(9); Cl(1)–Ru(1)–N(1), 85.09(11); Ru(1)–
O(1)–C(4), 126.6(3); Ru(1)–N(1)–C(2), 126.7(3).
Table 1. Crystallographic Data and Structure Refinement Parameters for 2 and 4a
2
4
Chemical Formula
FW
C22H28ClNORu
458.97
C22H25ClF3NORu
512.95

Page 7 of 24
Dalton Transactions
View Article Online
DOI: 10.1039/C8DT02677G
T/[K]
173(2)
0.71073
Monoclinic
P2(1)/c
9.0862(5)
13.8263(8)
16.6951(10)
90
173(2)
0.71073
Monoclinic
P2(1)/c
9.1752(4)
13.9311(7)
16.7961(8)
90
λ/Å
Crystal system
Space group
a/Å
b/Å
c/Å
α/°
β/°
103.385(3)
90
101.993(2)
90
γ/°
V/Å3
2040.4(2)
4
2100.03(17)
4
Z
ρ/Mg m–3
1.494
1.622
ꢀ/mm–1
5.509
5.097
F(000)
944
1040
θ range/°
4.737–59.420
15188
4.683–54.031
Reflections collected
Data/restraints/param.
Goodnessꢀofꢀfit on F2
13051
3818 / 37 / 311
4501 / 0 / 257
1.040
0.997
Final R indices
R1 = 0.0363
R1 = 0.0438,
wR2 = 0.1100
[I>2σ(I)a]
wR2 = 0.0922
Largest diff.peak/ hole
(e Å–3)
0.853 / –0.789
0.843 / –1.149
2
2
2
2
2
a R1=Σ||F0|ꢀ|Fc||/Σ|F0| (based on reflections with F0 >2σF2). wR2=[Σ[w(F0 ꢀFc2)2]/Σ[w(F0 )2]]1/2; w=1/[σ2(F0 )+(0.095P)2]; P=[max(F0 ,
2
0)+2Fc2]/3(also with F0 >2σF2).
Catalytic Hydrogenation of Ketones. Reduction of aldehydes and ketones is traditionally achieved
using NaBH4 and LiAlH4 as reagents, however, the drawbacks of these methods are the air and
moisture sensitivity of the metal hydrides and the large amount of waste formation in the
hydrogenation process. Thus catalytic hydrogenation with late transition metal complexes using
molecule hydrogen as reduction reagent represents the sustainable and green chemical process,

Dalton Transactions
Page 8 of 24
View Article Online
DOI: 10.1039/C8DT02677G
which is crucial for largeꢀscale industries.26b With complexes 1‒4 in hand, the catalytic activity in
the reduction of ketones with molecular hydrogen was explored. Initial experiments were performed
on acetophenone as a model substrate at 60 °C, with 0.1 mol % catalyst in methanol. The pressure
of H2 was crucial to reach high conversion: from 1 to 5 atm, the conversion increased from 16 % to
95 % over the 6 h reaction time (Table 2, entries 1‒3). However, further increase of the pressure did
o
not show any promotion of the reaction (Table 2, entries 4 and 5). The temperature of 50 C is
proper for the reaction and only 36 % yield of the desired product was observed when the reaction
o
was performed at a low temperature of 30 C (Table 2, entries 6‒8). Solvent played an important
role in the reaction and MeOH was the best choice (Table 2, entries 9‒12). The reduction did not
work well in water presumably caused by the poor solubility of acetophenone in water (Table 2,
entry 13), however, 1ꢀphenylethanol was obtained in good yield when mixed solvent of MeOH/H2O
(v/v = 1/1) was used (Table 2, entry 14). Decreasing the catalyst loading (from 0.1 mol% to 0.01
mol%) led to a lower yield of product, the yield dropped from 94% to 79 % even over the 16 h
reaction time (Table 2, entry 15). All the halfꢀsandwich ruthenium complexes were efficient in the
reaction and no remarkable differences of activity were found (Table 2, entries 16‒18).
Table 2. Hydrogenation of ketones under Catalysis of Halfꢀsandwich Ruthenium Complexesa
entry
Cat.(mol%)
1 (0.1)
T/oC
60
H2/atm
Solvent
MeOH
MeOH
MeOH
MeOH
MeOH
MeOH
Yield/%b
TON
160
440
950
940
950
960
1
2
3
4
5
6
1
2
5
6
8
5
16
44
95
94
95
96
1 (0.1)
60
1 (0.1)
60
1 (0.1)
60
1 (0.1)
60
1 (0.1)
80

Page 9 of 24
Dalton Transactions
View Article Online
DOI: 10.1039/C8DT02677G
7
1 (0.1)
1 (0.1)
1 (0.1)
1 (0.1)
1(0.1)
50
30
50
50
50
50
50
50
50
50
50
50
50
5
5
5
5
5
5
5
5
5
5
5
5
5
MeOH
95
36
950
360
520
750
820
860
790
940
8
MeOH
CH2Cl2
9
52
10
11
12
13
14
15
16
17
18
19
toluene
75
DMF
82
1 (0.1)
1 (0.1)
1 (0.1)
1 (0.01)
2 (0.1)
3 (0.1)
4 (0.1)
1 (0.1)
THF
86
H2O
79
MeOH/H2O(1:1)
MeOH/H2O(1:1)
MeOH/H2O(1:1)
MeOH/H2O(1:1)
MeOH/H2O(1:1)
MeOH
94
48/73c
93
4800/7300
930
950
950
‒
95
95
traced
a Reaction conditions: under argon, an autoclave was charged with the catalyst and solvent (2.0 mL), followed by
b
ketone (1.0 mmol), in that order. The autoclave was then charged with H2 and heated in an oil bath; time: 6 h.
determined by 1H NMR on the crude reaction mixture. c Reaction time: 16 h. d PMe3 (0.2 mol%) was added.
With the optimized reaction conditions in hand (Table 2, entry 14), we explored the generality
of the reaction. In general, from regular aromatic ketones, the corresponding alcohols (Table 3,
5a−5n) were furnished in good to excellent yields with both electronꢀdonating and
electronꢀwithdrawing substituents. However, the reactivity was slightly lower for the reduction of
ketones with an electronꢀdonating group such as OMe (Table 3, 5e and 5f). A positional study using
oꢀ, mꢀ, and pꢀmethylacetophenone was performed in order to investigate the effects the substituent
position has upon the catalytic hydrogenation process, no obvious differences were found (Table 3,
5b‒d). Moreover, heteroaromatic substrates with thiophene and pyridine motifs were hydrogenated
smoothly under standard conditions (Table 3, 5p and 5q). Aliphatic ketones required longer reaction
time and higher temperature to obtain good yields (Table 3, 5o and 5r). Interestingly, the reaction is
chemoselective toward C=O, as the C=O of ester group was not reduced (Table 3, 5r). The catalytic

Dalton Transactions
Page 10 of 24
View Article Online
DOI: 10.1039/C8DT02677G
activity of the catalyst in this work is comparable to the results of the similar reported ruthenium
complexes. For steric hindrance5a (5g) and heterocycle substrates5b (5q and 5q), higher yields of the
products were given by using complex 1 as the catalyst, although longer reaction time was needed
for the catalytic system reported here.
Table 3. Scope of the Catalytic Hydrogenation of Carbonyl Compoundsd
aReaction conditions: under argon, an autoclave was charged with complex 1 (0.1 mol %) and MeOH/H2O (2.0
mL, v/v = 1:1), followed by ketone (1 mmol). The autoclave was then charged with H2 (5 atm). The mixture was
1
stirred for 6 h at 50 °C in an oil bath. The conversion (%) was determined by H NMR on the crude reaction
mixture. Isolated yields (%) are provided in parentheses. bReaction conditions: 80 oC, 10 h.
To further elucidate the possible mechanism of the hydrogenation process, the reactivity between
the catalyst and H2 was investigated. The NMR tube containing the solution of 1 (in dry C6D6 ) was
o
1
pressurized with H2 (5 atm). The solution was then kept at 50 C and monitored by H NMR. A
singlet was observed at δ ‒11.22 ppm, which indicating that the formation of metal hydride species
(see supporting information).27 We speculate that hydrido metal compound may serve as catalyst in
the hydrogenation process. The leave of Cl ligand occurred at high temperature in the presence of

Page 11 of 24
Dalton Transactions
View Article Online
DOI: 10.1039/C8DT02677G
high pressure H2 atmosphere. It is supported, by analogy with the mechanism of catalytic activation
of hydrogen by ruthenium chloride, that this step involves the heterolytic splitting of H2 with
formation of the hydrido ruthenium active species.28 The conclusion was further confirmed by the
experimental result that little hydrogenation takes place when PMe3 was used as additive in the
hydrogenation process under standard reaction conditions (Table 2, entry 19). As mentioned above,
the hydrogenation benefits from higher H2 pressure. So the reaction was monitored under different
pressure. Figure.2 shows that there is almost a linear correlation between the conversions and H2
pressure, indicating that H2 is probably involved in the rateꢀdetermining step of the hydrogenation.
Figure 2. Effect of H2 pressure on the hydrogenation process. Reaction conditions: 1.0 mmol of
1
acetonphenone, 0.1 mol% of catalyst, H2, 50 °C for 1 h. The conversion was determined by H
NMR.
Based on the above experimental results and previous reports, the possible mechanism has been
proposed. Under high temperature and pressure of H2, complex 1 reacted with H2 to give the
hydrido ruthenium intermediate as the catalytic active species. The catalytic cycle is made up of
three steps: reversible coordination of H2, turnoverꢀlimiting heterolytic cleavage of H2 into a
hydride and a proton to be taken up by the ketone, and subsequent transfer of the hydride to the

Dalton Transactions
Page 12 of 24
View Article Online
DOI: 10.1039/C8DT02677G
resulting oxonium cation. Mechanistic studies on the similar ionic pathway have been reported
previously (Figure 3).29, 30
Figure 3. Possible mechanism of the hydrogenation process
Catalytic Hydrogenation of Nitroarenes. Aromatic amines are widely utilized as intermediates for
the production of medicines, dyes and pigments. Among various types of synthetic routes, one
important method to obtain primary anilines is based on the selective reduction of nitroarenes.31 So
the catalytic system used above was also employed in the reduction of nitroarenes to test its
catalytic activity. The reactivity of the halfꢀsandwich ruthenium complex 1 was examined using
1ꢀchloroꢀ4ꢀnitrobenzene as a model substrate with 0.1 mol% catalyst loading (Table 4, entries 1‒5).
o
Preliminary results suggested 80 C and 3 atm of H2 is proper for the reaction (Table 4, entry 5).
The catalyst loading could be reduced by half to 0.05 mol % without apparent degradation of the
activity (Table 4, entry 6). Complex 4 was found to be the most active catalyst toward the
hydrogenation of nitroarenes. No products were determined in the absence of the catalyst. A survey
of various substrates showed that complex 4 at 0.05 mol % loading promotes efficiently and cleanly
the reduction of nitrobenzene derivatives substituted at the benzene ring (Table 5). Similar with the

Page 13 of 24
Dalton Transactions
View Article Online
DOI: 10.1039/C8DT02677G
results of the hydrogenation of ketones, electronic effects exhibited little influences on the reactivity,
the corresponding amines were furnished in good to high yields (Table 5, 6a−6o). The reactivity
was noticeably affected by steric hindrance, reduction of 2,6ꢀdiisopropylnitrobenzene was more
difficult and the product was given in low yield (Table 5, 6p). The ester, cyano and carboxyl groups
were unaffected under the optimal conditions (Table 5, 6g, 6o and 6q). The carboxyl group at the
para position of the phenyl ring also inhibited the reaction (Table 5, 6q). This lack of reactivity
might be attributed to the instability of the catalyst toward the acidic functional groups. Not
unexpectedly, aliphatic substrate showed weak reactivity in the reduction process (Table 5, 6r).
Additionally, polynitro compounds were smoothly reduced (Table 5, 6s−6v). The catalyst exhibited
higher catalytic activity for alkyl substrates (6r) than that of the similar halfꢀsandwich Ru catalyst
used in transfer hydrogenation process.5b
Table 4. Hydrogenation of ketones under Catalysis of Halfꢀsandwich Ruthenium Complexesa
entry
Cat.(mol%)
1 (0.1)
T/oC
60
60
60
60
80
80
80
80
80
80
H2/atm
Yield/%b
26
TON
260
1
2
3
3
4
5
6
7
8
9
1
2
3
5
3
3
3
3
3
3
1 (0.1)
53
530
1 (0.1)
76
760
1 (0.1)
75
750
1 (0.1)
91
910
1 (0.05)
1 (0.02)
2 (0.05)
3 (0.05)
4 (0.05)
90
1800
3350
1840
1920
1960
67c
92
96
98
aReaction conditions: under argon, an autoclave was charged with the catalyst and solvent (2.0 mL), followed by

Dalton Transactions
Page 14 of 24
View Article Online
DOI: 10.1039/C8DT02677G
acetophenone (1.0 mmol), in that order. The autoclave was then charged with H2 and heated in an oil bath; time: 2
h. b determined by 1H NMR on the crude reaction mixture. cReaction time: 5 h.
Table 5. Scope of the Catalytic Hydrogenation of Nitro Compoundsa
OMe
NH2
NH2
NH2
NH2
NH2
NH2
MeO
6a 97% (95%b) 6b 95% (91%)
6c 95% (92%)
6d 93% (90%)
6e 83% (80%)
6f 81% (78%)
Cl
NH2
NH2
NH2
NH2
NH2
NH2
NC
6g 95% (92%)
I
F3C
Cl
Br
6h 98% (95%) 6i 98% (96%)
6j 94% (91%)
6k 96% (93%)
6l 89% (85%)
NH2
iPr
NH2
NH2
NH2
NH2
NH2
iPr
HO
H3COOC
HOOC
6m 90% (88%) 6n 92% (90%) 6o 88% (87%)
6p 69% (67%)
6q 75% (73%)
6r 71% (69%)
H2N
NH2
NH2
NH2
NH2
N
H2N
NH2
NH2
6t 89% (87%)
6s 91% (88%)
6u 93% (91%)
6v 90% (87%)
NH2
aReaction conditions: under argon, an autoclave was charged with complex 4 (0.05 mol %) and MeOH/H2O (2.0
mL, v/v = 1:1), followed by nitroarenes (1 mmol). The autoclave was then charged with H2 (3 atm). The mixture
was stirred for 2 h at 80 °C in an oil bath. The conversion (%) was determined by 1H NMR on the crude reaction
mixture. Isolated yields (%) are provided in parentheses.
Conclusions
In summary, a series of airꢀstable N, Oꢀchelate halfꢀsandwich ruthenium complexes based on
βꢀketoamino ligands have been synthesized smoothly. Such complexes feature the catalytic activity
for both ketones and nitroarenes hydrogenation by using H2 as the hydrogen source in aqueous
solution. The catalytic hydrogenation reactions occurred cleanly and rapidly with high TON values.

Page 15 of 24
Dalton Transactions
View Article Online
DOI: 10.1039/C8DT02677G
A survey of various kinds of substrates showed that both electronꢀpoor and electronꢀrich groups are
tolerance in the hydrogenation reaction. Evidence suggests that the hydrogenation process is
probably turnoverꢀcontrolled by the step of metal hydride formation.
Experimental Section
General Data. All manipulations were performed under an atmosphere of nitrogen using standard
1
Schlenk techniques. Chemicals were used as commercial products without further purification. H
NMR (500 MHz) spectra were measured with a Bruker DMXꢀ500 spectrometer. Elemental analysis
was performed on an Elementar vario EL III analyzer. IR (KBr) spectra were measured with the
Nicolet FTꢀIR spectrophotometer. Electrospray Ionization mass spectrometry was carried out on a
Waters API Quattro Micro triple quadrupole mass spectrometer in the positive ion mode. Ligands
L1‒L4 were prepared using the modified method according to the literature.23
Synthesis of βꢀketoamino ligands L1‒L4. The mixture of acetylacetone (2.0 mmol, 1.0 eq) and
corresponding aromatic amines (2.2 mmol, 1.1 eq) in EtOH (10 mL) in a 25 mL Schlenk tube was
refluxed at for 12 h. The reaction was then monitored by TLC. Column chromatography of the
crude products (PE : EA = 10 : 1) gave L1‒L4 in good yields.
L1: white solid, 85 % isolated yield. 1H NMR (500 MHz, CDCl3): δ 12.47 (brs, OH, 1H), 7.36 (t,
= 8.0 Hz, Ar–H, 2H), 7.21 (t, = 7.5 Hz, Ar–H, 1H), 7.12 (d, = 7.5 Hz, Ar–H, 2H), 5.19 (s, O–
CH, 1H), 2.10 (s, CH3, 3H), 1.99 (s, CH3, 3H). IR (KBr, disk): 3469, 1653, 1588, 1513, 1484,
J
J
J
C
=
υ
1384, 753 cm–1. Elemental analysis calcd (%) for C11H13NO: C 75.40, H 7.48, N 7.99, found: C
75.33, H 7.47, N 7.89.
L2: white solid, 85 % isolated yield. 1H NMR (500 MHz, CDCl3): δ 12.39 (brs, OH, 1H), 7.14 (d,
= 8.0 Hz, Ar–H, 2H), 7.00 (t, = 8.5 Hz, Ar–H, 2H), 5.16 (s, O–C CH, 1H), 2.34 (s, Ar–CH3, 3H),
2.09 (s, CH3, 3H), 1.95 (s, CH3, 3H). IR (KBr, disk): 3473, 1608, 1566, 1520, 1499, 1313, 761
J
J
=
υ

Dalton Transactions
Page 16 of 24
View Article Online
DOI: 10.1039/C8DT02677G
cm–1. Elemental analysis calcd (%) for C12H15NO: C 76.16, H 7.99, N 7.40, found: C 76.20, H 8.03,
N 7.38.
L3: white solid, 85 % isolated yield. 1H NMR (500 MHz, CDCl3): δ 12.43 (brs, OH, 1H), 7.31 (d,
= 8.5 Hz, Ar–H, 2H), 7.04 (t, = 8.5 Hz, Ar–H, 2H), 5.20 (s, O–C CH, 1H), 2.10 (s, CH3, 3H),
1.98 (s, CH3, 3H). IR (KBr, disk):
3455, 1616, 1567, 1502, 1481, 1384, 1278, 754 cm–1.
J
J
=
υ
Elemental analysis calcd (%) for C11H12ClNO: C 63.01, H 5.77, N 6.68, found: C 63.10, H 5.77, N
6.72.
L4: white solid, 85 % isolated yield. 1H NMR (500 MHz, CDCl3): δ 12.62 (brs, OH, 1H), 7.59 (d,
= 8.5 Hz, Ar–H, 2H), 7.20 (t, = 8.0 Hz, Ar–H, 2H), 5.26 (s, O–C CH, 1H), 2.12 (s, CH3, 3H),
2.08 (s, CH3, 3H). IR (KBr, disk):
3447, 1617, 1574, 1497, 1324, 1278, 1169, 775 cm–1.
J
J
=
υ
Elemental analysis calcd (%) for C12H12F3NO: C 59.26, H 4.97, N 5.76, found: C 59.23, H 5.02, N
5.85.
Synthesis of halfꢀsandwich ruthenium complexes 1–4. A mixture of [(
p
ꢀcymene)2RuCl2]2 (0.1
o
mmol), NaOAc (0.4 mmol), and corresponding ligands L1–L4 (0.2 mmol) was stirred at 50 C in
10 mL of methanol for 6 h. The mixture was filtered and evaporated to give the crude products
which were further purified by silica gel column chromatography (CH2Cl2 : EA = 8 : 1) to afford
pure N, Oꢀchelate halfꢀsandwich ruthenium complexes in moderate yields.
1
1: red solid, 63 % isolated yield. H NMR (500 MHz, CDCl3): δ 7.67 (d,
J
= 6.5 Hz, Ar–H, 1H),
= 6.5 Hz, Ar–H, 1H), 5.28
ꢀcymene–H, 1H), 4.98 (d, = 5.5 Hz,
= 5.5 Hz, ꢀcymene–H, 1H), 2.64‒2.58 (m,
(CH3)2, 1H), 1.99 (s, CH3 in ligand, 3H), 1.96 (s, CH3 in ligand, 3H), 1.62 (s, ꢀcymene–CH3,
3H), 1.19 (d, = 7.0 Hz, CH(C 3)2, 6H), IR (KBr, disk): 1734, 1653, 1588, 1513, 1412, 1384,
7.38 (t,
(d, = 5.5 Hz,
ꢀcymene–H, 1H), 4.73 (s, C
J
= 7.5 Hz, Ar–H, 2H), 7.19 (d,
ꢀcymene–H, 1H), 5.09 (d,
‒C=N, 1H), 3.60 (d,
J
= 7.0 Hz, Ar–H, 1H), 7.03 (d,
J
J
p
J
= 5.5 Hz,
p
J
p
H
J
p
C
H
p
J
H
υ

Page 17 of 24
Dalton Transactions
View Article Online
DOI: 10.1039/C8DT02677G
753 cm–1. Elemental analysis calcd (%) for C21H26ClNORu: C 56.68, H 5.89, N 3.15, found: C
56.65, H 5.78, N 3.09. MS (ESI, m/z): 410 [M–Cl]+.
1
2: dark red solid, 65 % isolated yield. H NMR (500 MHz, CDCl3): δ 7.56 (d,
J
= 7.0 Hz, Ar–H,
= 5.0 Hz, ꢀcymene–H,
ꢀcymene–H, 1H), 4.73 (s, C
(CH3)2, 1H), 2.39 (s, Ar‒CH3,
ꢀcymene–CH3, 3H), 1.21 (d, = 5.5 Hz, CH(C 3)2,
1728, 1637, 1584, 1503, 1413, 1385, 873, 741 cm–1. Elemental analysis calcd
1H), 7.18 (d,
J
= 11.5 Hz, 2H), 6.92 (d,
= 4.5 Hz, ꢀcymene–H, 1H), 4.97 (d,
= 4.0 Hz, ꢀcymene–H, 1H), 2.66‒2.60 (m, C
3H), 1.98 (brs, CH3 in ligand, 6H), 1.63 (s,
6H), IR (KBr, disk):
J
= 7.0 Hz, Ar–H, 1H), 5.29 (d,
J
p
1H), 5.12 (d,
J
p
J
= 5.0 Hz,
p
H‒
C=N, 1H), 3.63 (d,
J
p
H
p
J
H
υ
(%) for C22H28ClNORu: C 57.57, H 6.15, N 3.05, found: C 57.53, H 6.18, N 3.01. MS (ESI, m/z):
424 [M–Cl]+.
3: brown solids, 55 % isolated yield. 1H NMR (500 MHz, CDCl3): δ 7.68 (d,
7.36 (d, = 8.5 Hz, Ar–H, 2H), 6.69 (d, = 7.0 Hz, Ar–H, 1H), 5.30 (d, = 6.0 Hz,
1H), 5.14 (d, = 6.0 Hz, ꢀcymene–H, 1H), 4.94 (d, = 6.0 Hz, ꢀcymene–H, 1H), 4.74 (s, C
C=N, 1H), 3.69 (d, = 6.0 Hz, ꢀcymene–H, 1H), 2.65‒2.58 (m, C (CH3)2, 1H), 1.997 (s, CH3 in
ligand, 3H), 1.993 (s, CH3 in ligand, 3H), 1.62 (s, ꢀcymene–CH3, 3H), 1.21 (dd, = 7.0 Hz, 7.0 Hz,
CH(C 3)2, 6H), IR (KBr, disk):
1731, 1651, 1572, 1509, 1411, 1386, 870, 760 cm–1. Elemental
J
= 7.0 Hz, Ar–H, 1H),
J
J
J
p
ꢀcymene–H,
J
p
J
p
H‒
J
p
H
p
J
H
υ
analysis calcd (%) for C21H25Cl2NORu: C 52.61, H 5.26, N 2.92, found: C 52.49, H 5.28, N 2.99.
MS (ESI, m/z): 444 [M–Cl]+.
1
4: dark red solids, 60 % isolated yield. H NMR (500 MHz, CDCl3): δ 7.87 (d,
J
= 8.0 Hz, Ar–H,
= 6.0 Hz, ꢀcymene–H,
ꢀcymene–H, 1H), 4.79 (s, C
ꢀcymene–H, 1H), 2.65‒2.59 (m, C (CH3)2, 1H), 2.02 (s, CH3 in
ligand, 3H), 1.98 (s, CH3 in ligand, 3H), 1.63 (s, ꢀcymene–CH3, 3H), 1.21 (d, = 7.0 Hz,
1H), 7.68‒7.64 (m, Ar–H, 2H), 7.17 (d,
1H), 5.13 (d, = 6.0 Hz, ꢀcymene–H, 1H), 4.98 (d,
C=N, 1H), 3.65 (d, = 6.0 Hz,
J
= 7.5 Hz, Ar–H, 1H), 5.32 (d,
J
p
J
p
J
= 6.0 Hz,
p
H‒
J
p
H
p
J

Dalton Transactions
Page 18 of 24
View Article Online
DOI: 10.1039/C8DT02677G
CH(CH3)2, 6H), IR (KBr, disk): υ
1714, 1607, 1583, 1504, 1410, 1375, 878, 761 cm–1. Elemental
analysis calcd (%) for C22H25ClF3NORu: C 51.51, H 4.91, N 2.73, found: C 51.66, H 4.88, N 2.80.
MS (ESI, m/z): 478 [M–Cl]+.
General Procedure for the Hydrogenation of Ketones. In a typical run, the substrate (1.0 mmol),
catalyst (0.1 mol%) and MeOH/H2O (2 mL, v/v = 1/1) were charged in a 5 mL vial with a magnetic
bar. The vial was then transferred to an autoclave. The autoclave was purged with H2 (5 atm) via
three cycles of pressurization/venting, then pressurized with H2 (5 atm) and disconnected from the
o
H2 source. The autoclave was heated to 60 C. After stirring for 6 h, the autoclave was cooled and
the pressure was slowly released. The resultant mixture extracted with diethyl ether (2 × 5 mL) and
dried over anhydrous Na2SO4. Solvent was evaporated under vacuum. The residue was dissolved in
hexane and analyzed by GCꢀMS.
General Procedure for the Hydrogenation of Nitroarenes. In a typical run, the substrate (1.0
mmol), catalyst (0.05 mol%) and MeOH/H2O (2 mL, v/v = 1/1) were charged in a 5 mL vial with a
magnetic bar. The vial was then transferred to an autoclave. The autoclave was purged with H2 (3
atm) via three cycles of pressurization/venting, then pressurized with H2 (3 atm) and disconnected
o
from the H2 source. The autoclave was heated to 80 C. After stirring for 3 h, the autoclave was
cooled and the pressure was slowly released. The resultant mixture extracted with diethyl ether (2 ×
5 mL) and dried over anhydrous Na2SO4. Solvent was evaporated under vacuum. The residue was
dissolved in hexane and analyzed by GCꢀMS.
Xꢀray Crystallography. Diffraction data of 2 and 4 were collected on a Bruker Smart APEX CCD
diffractometer with graphiteꢀmonochromated MoKa radiation (λ = 0.71073 Å). All the data were
collected at room temperature, and the structures were solved by direct methods and subsequently
refined on F2 by using fullꢀmatrix leastꢀsquares techniques (SHELXL).32 SADABS33 absorption

Page 19 of 24
Dalton Transactions
View Article Online
DOI: 10.1039/C8DT02677G
corrections were applied to the data, all non–hydrogen atoms were refined anisotropically, and
hydrogen atoms were located at calculated positions. All calculations were performed using the
Bruker program Smart.
Supporting Information
Electronic supplementary information (ESI) available: 1H NMR spectra of L1‒L4, Complexes 1‒4;,
TGA curves of complex 1‒4; Crystallographic data. CCDC 1852640 (2) and 1852641 (4).
Acknowledgements
This work was supported by the National Natural Science Foundation of China (No. 21601125), the
Chenguang Scholar of Shanghai Municipal Education Commission (No. 16CG64), Natural Science
Foundation of Shanghai (No. 16ZR1435700), Shanghai Science and Technology Committee
(16DZ2270100), the Shuguang Scholar of Shanghai Municipal Education Commission (No.
16SG49), the Shanghai Municipal Education Commission (Plateau Discipline Construction
Program).
Notes and references
1 The Handbook of Homogeneous Hydrogenation, ed. J. G. de Vries and C. J. Elsevier, WileyꢀVCH,
Weinheim, 2007.
2 (a) F. Schmitt, J. Freudenreich, N. P. E. Barry, L. JuilleratꢀJeanneret, G. SüssꢀFink, B. Therrien, J.
Am. Chem. Soc., 2012, 134, 754–757; (b) J. Palmucci, F. Marchetti, R. Pettinari, C. Pettinari, R.
Scopelliti, T. Riedel, B. Therrien, A. Galindo, and P. J. Dyson, Inorg. Chem., 2016, 55, 11770–
11781; (c) A. Gatti, A. Habtemariam, I. RomeroꢀCanelón, J.ꢀI. Song, B. Heer, G. J. Clarkson, D.
Rogolino, P. J. Sadler, and M. Carcelli, Organometallics, 2018, 37, 891–899; (f) A. Robertson, T.
Matsumoto, and S. Ogo, Dalton Trans., 2011, 40, 10304–10310; (g) P. Crochet, and V. Cadierno,

Dalton Transactions
Page 20 of 24
View Article Online
DOI: 10.1039/C8DT02677G
Dalton Trans., 2014, 43, 12447–12462; (h) G. SüssꢀFink, J. Organomet. Chem., 2014, 751, 2–19; (i)
F. Foubelo, C. Nájera, and M. Yus, Tetrahedron: Asymmetry, 2015, 26, 769–790; (j) V.
Mannancherril, and B. Therrien. Inorg. Chem., 2018, 57, 3626–3633; (k) A. Garci, J.ꢀP. Mbakidi, V.
Chaleix, V. Sol, E. Orhan, and B. Therrien, Organometallics, 2015, 34, 4138–4146; (m) A.
PittoꢀBarry, N. P. E. Barry, V. Russo, B. Heinrich, B. Donnio, B. Therrien, and R. Deschenaux,
Designing Supramolecular LiquidꢀCrystalline Hybrids from PyrenylꢀContaining Dendrimers and
Arene Ruthenium Metallacycles. J. Am. Chem. Soc., 2014, 136, 17616–17625.
3 L. T. Ghoochany, S. Farsadpour, Y. Sun, and W. R. Thiel, Eur. J. Inorg. Chem., 2011, 3431‒3437.
4 (a) S. Karabuga, S. Bars, I. Karakaya, and S. Gumus, Tetrahedron Lett., 2015, 56, 101‒104, (b) R.
Noyori, and T. Ohkuma, Angew. Chem. Int. Ed., 2001, 40, 40‒73.
5 (a) T. Ohkuma, H. Ooka, S. Hashiguchi, T. Ikariya, and R. Noyori, J. Am. Chem. Soc., 1995, 117,
2675‒2676, (b) W. ꢀG. Jia, H. Zhang, T. Zhang, D. Xie, S. Ling, and E. ꢀH., Sheng.
Organometallics, 2016, 35, 503‒512, (c) T.ꢀH. Lin, K. Das, A. Datta, W.ꢀJ. Leu, H.ꢀC. Hsiao, C.ꢀH.
Li, J.ꢀH. Guh, and J.ꢀH. Huang, J. Organomet. Chem., 2016, 807, 22‒27, (d) C.ꢀM. Hsiao, Y.ꢀF.
Chen, C.ꢀH. Lin, C.ꢀH. Hu, Y.ꢀR. Cai, and J.ꢀH. Huang, J. Organomet. Chem., 2018, 861, 10‒16, (e)
Y.ꢀH. Chang, W.ꢀJ. Leu, A. Datta, H.ꢀC. Hsiao, C.ꢀH. Lin, J.ꢀH. Guh, and J.ꢀH. Huang, Dalton
Trans., 2015, 44, 16107–16118.
6 (a) W. Jin, L. Wang, and Z. Yu, Organometallics, 2012, 31, 5664‒5667, (b) F. Zeng, and Z. Yu,
Organometallics, 2008, 27, 2898‒2901, (c) W. Ye, M. Zhao, W. Du, Q. Jiang, K. Wu, P. Wu, Z. Yu,
Chem. Eur. J., 2011, 17, 4737‒4741, (d) O. Dayan, and B. Cetinkaya, J. Mol. Catal. A: Chem., 2007,
271, 134‒141, (e) I. Sahin, S. Emir, E. Ispir, I. Karakaya, S. Gumus, M. Ulusoy, and S. Karabuga,
Cat. Commun., 2016, 85, 30‒33.
7 (a) W. Baratta, L. Fanfoni, S. Magnolia, K. Siega, and P. Rigo, Eur. J. Inorg. Chem., 2010, 1419‒

Page 21 of 24
Dalton Transactions
View Article Online
DOI: 10.1039/C8DT02677G
1423, (b) W. Baratta, K. Siega, and P. Rigo, Chem. Eur. J., 2007, 13, 7479‒7486, (c) W. Baratta, F.
Benedetti, A. Del Zotto, L. Fanfoni, F. Felluga, S. Magnolia, E. Putignano, and P. Rigo,
Organometallics, 2010, 29, 3563‒3570.
8 (a) R. V. Jagadeesh, G. Wienhofer, F. A. Westerhaus, A. E. Surkus, H. Junge, K. Junge, and M.
Beller, Chem. Eur. J. 2011, 17, 14375‒14379, (b) M. Rueping, A. R. Antonchick, and T.
Theissmann, Angew. Chem. Int. Ed., 2006, 45, 3683‒3686, (c) S. Sanz, M. Benitez, and E. Peris,
Organometallics, 2010, 29, 275‒277, (d) W. Baratta, E. Herdtweck, K. Siega, M. Toniutti, and P.
Rigo, Organometallics, 2005, 24, 1660‒1669, (e) F. Zeng, and Z. Yu, Organometallics, 2009, 28,
1855‒1862, (f) Y. Li, H. Zhang, J. Chen, X. Liao, Z. Dong, and J. Gao, J. Mol. Catal. A Chem.
2004, 218, 153‒156, (g) L. Gok, and H. Turkmen, Tetrahedron, 2013, 69, 10669‒10674.
,
9 (a) M. M. Sheeba, M. Muthu Tamizh, L. J. Farrugia, A. Endo, and R. Karvembu, Organometallics
2014, 33, 540‒550, (b) O. Prakash, H. Joshi, K. N. Sharma, P. L. Gupta, A. K. Singh,
Organometallics, 2014, 33, 3804‒3812, (c) C. Romain, S. Gaillard, M. K. Elmkaddem, L. Toupet,
C. Fischmeister, C. M. Thomas, and J. ꢀL. Renaud, Organometallics, 2010, 29, 1992‒1995, (d) M.
C. Carrion, F. Sepulveda, F. A. Jalon, B. R. Manzano, and A. M. Rodríguez, Organometallics, 2009,
28, 3822‒3833, (e) Z. Fang, and M. Wills, J. Org. Chem., 2013, 78, 8594‒8605, (f) A. M. Hayes, D.
J. Morris, G. J. Clarkson, and M. Wills, J. Am. Chem. Soc., 2005, 127, 7318‒7319.
10 (a) B. L. Conley, M. K. PenningtonꢀBoggio, E. Boz, and T. J. Williams, Chem. Rev., 2010, 110,
2294‒2312, (b) J. R. Khusnutdinova, and D. Milstein, Angew. Chem. Int. Ed., 2015, 54, 12236‒
12273.
,
11 (a) Y. ꢀF. Han, and G. ꢀX. Jin, Acc. Chem. Res., 2014, 47, 3571‒3579, (b) Y. ꢀF. Han, and G. ꢀX.
Jin, Chem. Soc. Rev., 2014, 43, 2799‒ 2823.
12 (a) R. Zhang, L. Zhu, G. Liu, H. Dai, Z. Lu, J. Zhao, and H. Yan, J. Am. Chem. Soc., 2012, 134,

Dalton Transactions
Page 22 of 24
View Article Online
DOI: 10.1039/C8DT02677G
10341–10344, (b) Z. Wang, H. Ye, Y. Li, Y. Li, and H. Yan, J. Am. Chem. Soc., 2013, 135, 11289–
11298.
13 P. Kumar, R. K. Gupta, and D. S. Pandey, Chem. Soc. Rev., 2014, 43, 707‒733.
14 J. M. Gichumbi, H. B. Friedrich, and B. Omondi, J. Organomet. Chem., 2016, 808, 87‒96.
15 (a) J. Tauchman, B. Therrien, G. SüssꢀFink, P. Štěpnička, Organometallics, 2012, 31, 3985‒3994,
(b) V. Mannancherril, and B. Therrien, Inorg. Chem., 2018, 57, 3626–3633, (c) J. Freudenreich, C.
Dalvit, G. SüssꢀFink, and B. Therrien, Organometallics, 2013, 32, 3018–3033.
16 A. M. Tafesh, and J. Weiguny, Chem. Rev., 1996, 96, 2035−2052.
17 S. Kim, H. Choi, C. Baik, K. Song, S. O. Kang, and J. Ko, Tetrahedron, 2007, 63, 11436‒11443.
18 K. Kondo, H. Ogawa, T. Shinohara, M. Kurimura, Y. Tanada, K. Kan, H. Yamashita, S.
Nakamura, T. Hirano, Y. Yamamura, T. Mori, M. Tominaga, A. Itai, J. Med. Chem., 2000, 43, 4388‒
4397.
19 (a) Q. Hu, J. Chen, Z. Zhang, Y. Liu and W. Zhang, Org. Lett., 2016, 18, 1290–1293; (b) A. Ruff,
C. Kirby, B. C. Chan and A. R. O’Connor, Organometallics, 2016, 35, 327–335; (c) X. Tan, G.
Wang, Z. Zhu, C. Ren, J. Zhou, H. Lv, X. Zhang, L. W. Chung, L. Zhang and X. Zhang, Org. Lett.
,
2016, 18, 1518–1521.
20 P. Tomkins, E. GebauerꢀHenke, W. Leitner, T. E. Muller, ACS Catal., 2015, 5, 203‒209.
21 A. I. Carrillo, K. G. Stamplecoskie, M. L. Marin, and J. C. Scaiano, Catal. Sci. Technol., 2014, 4,
1989‒1996.
22 A. Indra, N. Maity, P. Maity, S. Bhaduri, and G. K. Lahiri, J. Catal., 2011, 284, 176−183.
23 X. He, Y. Yao, X. Luo, J. Zhang, Y. Liu, L. Zhang, and Q. Wu, Organometallics, 2003, 22, 4952‒
4957.
24 L. C. Matsinha, S. F. Mapolie, and G. S. Smith, Polyhedron, 2013, 53, 56‒61.

Page 23 of 24
Dalton Transactions
View Article Online
DOI: 10.1039/C8DT02677G
25 P. Govender, A. K. Renfrew, C. M. Clavel, P. J. Dyson, B. Therrien, and G. S. Smith, Dalton
Trans., 2011, 40, 1158‒1167.
26 (a) P. Kumar, R. K. Gupta, and D. S. Pandey, Chem. Soc. Rev., 2014, 43, 707‒733; (b) Z. ꢀJ. Yao,
K. Li, J. ꢀY. Zhang, and W. Deng, New J. Chem., 2016, 40, 8753‒8759.
27 J. Zhang, E. Balaraman, G. Leitus, and D. Milstein, Organometallics 2011, 30, 5716
28 J. Halpern, J. F. Harrod, and B. R. James, J. Am. Chem. Soc., 1966, 88, 5150‒5155.
29 J. S. M. Samec and J. E. Backvall, Chem. Eur. J., 2002, 8, 2955‒2961.
−5724.
30 C. P. Casey, S. W. Singer, D. R. Powell, R. K. Hayashi, and M. Kavana, J. Am Chem. Soc., 2001,
123, 1090‒1100.
31 (a) R. K. Rai, A. Mahata, S. Mukhopadhyay, S. Gupta, P.ꢀZ. Li, K. T. Nguyen, Y. Zhao, B.
Pathak, and S. K. Singh, Inorg. Chem., 2014, 53, 2904‒2909; (b) J. Liu, J. Cui, F. Vilela, J. He, M.
Zeller, A. D. Hunter, and Z. Xu, Chem. Commun., 2015, 51, 12197‒12200, (c) W. ꢀG. Jia, Y. ꢀC. Dai,
H. ꢀN. Zhang, X. Lu, and E. ꢀH. Sheng, RSC Adv., 2015, 5, 29491‒29496; (d) Z. Zhao, H. Yang, Y.
Li, X. Guo, Green Chem., 2014, 16, 1274‒1281; (e) X. ꢀJ. Yang, B. Chen, L. ꢀQ. Zheng, L. ꢀZ. Wu,
and C. ꢀH. Tung, Green Chem., 2014, 16, 1082‒1086; (f) N. S. Sanjini, and S. Velmathi, RSC Adv.
,
2014, 4, 15381‒15388; (g) G. Wienhofer, I. Sorribes, A. Boddien, F. Westerhaus, K. Junge, H.
Junge, R. Llusar, M. Beller, J. Am. Chem. Soc., 2011, 133, 12875‒12879; (h) W. ꢀG. Jia, T. Zhang,
D. Xie, Q. ꢀT. Xu, S. Ling, and Q. Zhang, Dalton Trans, 2016, 45, 14230‒14237.
32 G. M. Sheldrick, SHELXLꢀ97, Program for the Refinement of Crystal Structures, Universität
Gtötingen: Germany, 1997.
33 G. M. Sheldrick, SADABS (2.01), Bruker/Siemens Area Detector Absorption Correction
Program; Bruker AXS: Madison, WI, 1998.

Dalton Transactions
Page 24 of 24
View Article Online
DOI: 10.1039/C8DT02677G
Catalytic Hydrogenation of Carbonyl and Nitro Compounds Using
[NO]-chelate Half-Sandwich Ruthenium Catalyst
Zi-Jian Yao,* Jing-Wei Zhu, Nan Lin, Xin-Chao Qiao, Wei Deng*
a School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai,
201418, China.
TOC
A series of N,O-chelate half-sandwich ruthenium complexes have been synthesized which
exhibited high activity for catalytic hydrogenation of carbonyl and nitro compounds in aqueous
solution.