Polystyrene stabilized iridium nanoparticles catalyzed chemo- and regio-selective semi-hydrogenation of nitroarenes to N-arylhydroxylamines

Article abstract of DOI:10.1016/j.mcat.2021.111836

Polystyrene stabilized Iridium (Ir@PS) nanoparticles (NPs) as a heterogeneous catalyst have been developed and characterized by IR, UV–Vis, SEM, TEM, EDX and XRD studies. The prepared Ir@PS catalyst showed excellent reactivity for chemo- and regio-selective controlled-hydrogenation of functionalized nitroarenes to corresponding N-arylhydroxylamine using hydrazine hydrate as reducing source and environmentally benign polyethylene glycol (PEG-400) as green solvent. The present methodology was applied for vast substrate scope and found to be compatible with wide range of reducible functional groups. The reaction performed at 85 °C or ambient temperature and completed within 5–80 minutes. The catalyst can easily be filtered out from reaction mixture and reusable.

Full text of DOI:10.1016/j.mcat.2021.111836

Molecular Catalysis 514 (2021) 111836
Contents lists available at ScienceDirect
Molecular Catalysis
journal homepage: www.journals.elsevier.com/molecular-catalysis
Polystyrene stabilized iridium nanoparticles catalyzed chemo- and
regio-selective semi-hydrogenation of nitroarenes to N-arylhydroxylamines
a,
‡
b
,
c,
‡
b
,
c
a,d
Dhananjay Bhattacherjee , Shaifali
Pralay Das
, Ajay Kumar , Grigory V. Zyryanov
,
b,c,*
a
Department of Organic & Biomolecular Chemistry, Chemical Engineering Institute, Ural Federal University, 19 Mira Str., 620002 Yekaterinburg, Russian Federation
Chemical Technology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, 176061, H.P., India
b
c
Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
d
I. Ya. Postovskiy Institute of Organic Synthesis, Ural Division of the Russian Academy of Sciences, 22 S. Kovalevskoy Str., Yekaterinburg 620219, Russian Federation
A R T I C L E I N F O
A B S T R A C T
Keywords:
Polystyrene stabilized Iridium (Ir@PS) nanoparticles (NPs) as a heterogeneous catalyst have been developed and
characterized by IR, UV–Vis, SEM, TEM, EDX and XRD studies. The prepared Ir@PS catalyst showed excellent
reactivity for chemo- and regio-selective controlled-hydrogenation of functionalized nitroarenes to corre-
sponding N-arylhydroxylamine using hydrazine hydrate as reducing source and environmentally benign poly-
ethylene glycol (PEG-400) as green solvent. The present methodology was applied for vast substrate scope and
Supported iridium nanoparticles
N-arylhydroxylamine
Semi-hydrogenation
Chemo- and regioselective reduction
Recyclability
◦
found to be compatible with wide range of reducible functional groups. The reaction performed at 85 C or
ambient temperature and completed within 5–80 minutes. The catalyst can easily be filtered out from reaction
mixture and reusable.
Introduction
catalytic activity of Pt@Ir zigzag bimetallic nano-complexes for hydro-
genation of nitroarenes but aniline was formed as end product [37]. In
The semi-hydrogenation of functionalized nitroarenes is one of the
powerful strategy to obtain highly reactive N-arylhydroxylamines which
have found its application as useful intermediates for industrially
valuable fine chemical synthesis [1-4], bioactive pharmaceuticals [5–7]
and polymerization inhibitors [8-9]. Among the reported protocols
available for N-arylhydroxylamine synthesis, majorly involved in cross
coupling reaction of hydroxylamine with aryl halides [10], biocatalytic
reduction by the application of bakers’ yeast or plant cell from grape
2015, Cai research group reported homogeneous iridium catalysis in the
transfer hydrogenation process of nitroarenes using isopropanol as
H-donor under stronger basic conditions [38]. The mechanistic studies
revealed the intermediacy of the N-arylhydroxylamine for the synthesis
of anilines. The chemo-selective hydrogenation of nitroaromatics is
known under Poly(N-vinyl-2-pyrrolidone) (PVP)-stabilized iridium
nanoparticles (Ir NPs) catalysis. [39] These colloidal iridium nano-
particles showed very good functional group tolerance in the hydroge-
nation of nitroaromatics to anilines. Iridium and gold as
heterobimetallic complex were also reported for the reduction of
nitroarenes to aminoarenes via transfer hydrogenation using primary
alcohols [40]. Although, the gold catalyst under reaction conditions
gives rise to the formation of hydroxyl amines in good yields. The
(
Vitis vinifera L.) [11], borohydride reduction of aldoxime or nitro
groups [12-18], use of Zn, Sn, Sb or Bi in stoichiometric quantity [8, 13,
9-22], homogeneous Rh-complex with hydrazine [23,24] and sup-
ported platinum catalyst either with hydrazine or H
1
2
pressure [25–27].
In 2015, Doris et al. reported carbon nanotube-ruthenium nanohybrid
for selective conversion of nitroarenes to N-arylhydroxylamines but,
regio-selectivity has not been described. [28]
III
I
Ir -Au dual catalysis therefore responsible for the synthesis of aromatic
amines rather than hydroxyl amines. Actually, semi-hydrogenation of
nitroarenes proceeded through number of intermediates and the sta-
bility of each intermediate depends on kinetics of the step involved,
concentration of reducing agent, surface design of the support and size
and shape of metal nanoparticles [41-42]. Moreover, formation of
Scheme 1
In recent years, immobilized iridium nanoparticles (NPs) have been
widely used as a heterogeneous catalyst for various organic trans-
formations [29-36]. Very recently, Gu and co-workers reported good
*
Corresponding author: Dr. Pralay Das, Chemical Technology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur-176061, H.P., India
Contributed equaly.
‡
https://doi.org/10.1016/j.mcat.2021.111836
Received 18 May 2021; Received in revised form 10 August 2021; Accepted 16 August 2021
Available online 28 August 2021
2
468-8231/© 2021 Elsevier B.V. All rights reserved.

D. Bhattacherjee et al.
Molecular Catalysis 514 (2021) 111836
Fig. 1. (a) SEM image, (b) SEM-EDS, (c) TEM image, (d) Particle distribution histogram, (e) High Resolution TEM image (FFT in right inset), (f) SAED pattern of the
polystyrene stabilized iridium nanoparticle, (g) X-ray diffraction pattern of Ir (0) nanoparticle.
by-products largely reduces the possibility of N-arylhydroxylamine
formation through hydrogenation of nitroarenes. The hydrogenation of
halogen substituted nitroarenes by supported iridium catalyst was usu-
ally avoided because hydrogenation always accompanied by hydro-
genolysis of the carbon-halogen bond [43]. Therefore, catalytic property
of heterogeneous iridium must be modified by proper selection of solid
matrix.
nanoparticle over solid matrix. The TEM image showed the impregna-
tion of Ir (0) and the particle size of maximum number of nano-particles
was found between 1 and 4 nm (Fig. 1c and 1d). HRTEM image of Ir@PS
given in Fig. 1(e) exhibited the highly crystalline nature of the syn-
thesised iridium nanoparticle and an interplaner spacing of
coincides to the (111) plane of FCC lattice.
̴ 0.218 nm
The SAED pattern presented in the Fig. 1(f) contained diffraction
rings corresponding to (111), (200) and (311) crystallographic planes
confirming the existence of crystallites of Ir NPs which is consistent with
observed d-spacing with XRD measurements (Fig. 1g). [49-52] HR-TEM
with field emission gun revealed high crystallinity of Ir having a
d-spacing 0.218 nm which corresponds to reflection plane. Electron
diffractogram pattern of the marked region in Fig. 1(e) gave a lattice
spacing 0.218 nm which indicates only (111) reflections in Fast Fourier
Transformation (FFT) graph. The ICP-AES analysis was performed and
the results are in good agreement with the heterogeneity of the Ir@PS
(Table S1, Supporting information). Therefore, transfer hydrogenation
of nitroarenes took place by Ir@PS which is truly heterogeneous in na-
ture and negligible amount of Ir, which is too low to react, was leached
out during reaction.
Over the past decades, our group is dedicatedly working in the area
of development of metal nanoparticles and their applications in diverse
area of organic transformations. [44-48] In this present context, we have
reported the synthesis and characterization of Ir@PS as heterogeneous
catalyst for the highly selective controlled hydrogenation of function-
alized nitroarenes to N-arylhydroxylamines.
Typically, the generation of transition metal nanoparticles (MNPs)
involves reduction of metal salts in presence of stabilizing agent to
prevent MNPs aggregation during its deposition over solid matrix. In our
study, the Ir@PS was prepared by reduction-deposition technique
(
Supporting Information). The conversion of Ir (III) to Ir (0) in solution
phase was monitored by UV–visible absorption spectroscopy and the
gradual disappearance of peak at around λmax = 290 nm was observed
(
Fig. S2, Supporting information).
We started our initial investigation by choosing nitrobenzene as
easily available bench stable model substrate. Among the different
tested conditions, we found Ir@PS as a compatible heterogeneous nano-
catalyst for controlled hydrogenation process with hydrazine hydrate at
The prepared Ir@PS was further characterized by electron micro-
scopy studies (SEM, TEM & HR-TEM), SAED, Electron dispersive X-ray
(
EDX) and powder X-ray crystallography (Fig. 1).
◦
SEM analysis showed the deposition and distribution of Ir (0)
85 C temperature. After screening of various solvents, we have
2

D. Bhattacherjee et al.
Molecular Catalysis 514 (2021) 111836
Table 1
Optimization of reaction conditions.
a
◦
b
Reaction conditions: 1a (100 mg, 0.81 mmol), Ir@PS (2 mol%), hydrazine hydrate (3.25 mmol), PEG-400 (2 mL), 85 C, 30 min; isolated yield; nd = not detected, nr
=
no reaction.
observed that THF was found to be equally suitable for hydrogenation as
PEG-400 but it was chosen over THF for its environmental benignity
to corresponding N-aryl hydroxylamine. Actually, regio-selective sem-
i-hydrogenation of nitroarenes remained a big challenge especially
under iridium catalyzed condition and not a single precedent was found
in the literature. Interestingly, under Ir@PS catalyzed condition
regio-selective hydrogenation of di-nitroarenes 1o-q to the corre-
sponding N-aryl hydroxylamine 2o-q were achieved in 89–99% yield.
Previous reports suggested that iridium NPs have some affinity to co-
ordinate with C = C double bond under reducing atmosphere. [53-55]
Owing to these, in most of the transfer hydrogenation of nitroarenes in
presence of catalytic iridium nanoparticle carbon multiple bonds have
been avoided. In 2014, Motoyama and co-workers have reported the
catalytic activity of carbon nanofiber-supported iridium nanoparticle
towards chemoselective hydrogenation of nitroarenes containing C = C
double bond to corresponding amine [36]. In such case, formation of
considerable amount of C = C double bond hydrogenated product was
observed. We were therefore, encouraged to address the above limita-
tions by employing Ir@PS catalyzed standard reaction conditions for the
(
Entry 14, Table 1). The best result was obtained when 1 equivalent of
nitrobenzene 1a reacted with Ir@PS (2 mol% Ir), 4 equivalent of hy-
◦
drazine hydrate at 85 C temperature in PEG-400 (2 mL) for 30 mins
(
Table 1, Entry 7).
The standard parameters were further employed to investigate the
substrate versatility as well as chemo- and regio-selectivity for the
transfer hydrogenation of nitroarenes. Electron rich 4-methyl nitro-
benzene 1b excellently gave 2b in 90% yield (Table 2, Entry 1). Previous
reports showed that halogen substituted nitroarenes are not suitable
substrates for the iridium catalyzed hydrogenation as the dehalogena-
tion is the major drawback. [17] Surprisingly, in our catalytic system
halogen substituted nitrobenzenes 1c-d under standard reaction condi-
tions afforded 2c-d in 93–96% yields without formation of any deha-
logenated product (Table 2, Entry 2–3). Moreover, the reductively
vulnerable functional group substituted nitroarenes such as COCH
CO CH , -COOH were showed excellent chemo-selectivity and delivered
e-g in 87–95% yields (Table 2, Entry 4–6). In the case of substrate 1h
3
,
semi-hydrogenation of nitroarenes in presence of C C multiple bond.
–
To our delight, 4-nitrostyrene 1r selectively reduced to 2r in 91% yield
under optimized reaction condition (Table 2, entry 17) and no di-hydro
product was observed.
2
3
2
full conversion to 2h was noted only after 15 min reaction time (Table 2,
Entry 7). Next, electron withdrawing nitroarenes 1i-j smoothly got
reduced to corresponding hydroxylamine 2i-j in 98–99% yields (Table 2,
Entry 8–9). Interestingly, reduction of dihalo-substituted nitroarens 1k-l
to desired hydroxylamine 2k-l were achieved in excellent yield (Table 2,
Entry 10–11) but the reaction took little longer time to complete. In our
study, sterically hindered nitroarene 1m gave corresponding reduced
product 2m in 80% yield. The protocol was found to be equally efficient
for heterocyclic nitroarene 1n which gave the respective 2n in 87%
yields (Table 2, Entry 13). Further, the scope of the present protocol has
also been extended to the regio-selective hydrogenation of nitroarenes
Furthermore, the recyclability of Ir@PS was also checked using
nitrobenzene as model substrate, shown in Fig. 2. We have removed the
catalyst using simple filtration and washed with acetone and methanol.
Thereafter, the catalyst was dried under vacuum using rotary evaporator
and used for next catalytic cycle. During the recyclability study, we have
noticed the significant reduction in the rate of conversion of nitro ben-
zene and decrease in the catalytic activity of Ir@PS. The reason of this
diminishing catalytic activity may be attributed to the large size of the
iridium NPs and concurrent aggregation during the reaction. To support
3

D. Bhattacherjee et al.
Molecular Catalysis 514 (2021) 111836
Table 2
Functional group tolerance in chemo- and regio-selective transfer
hydrogenation.
Fig. 2. Recyclability experiments.
Scheme 1. Strategies of N-arylhydroxyl amine synthesis via transfer hydroge-
nation reaction.
Scheme 2. Proposed mechanism of semi-hydrogenation of nitroarenes cata-
lyzed by Ir@PS.
this fact, we have recorded the TEM (50 nm) and SEM-EDX of the
recycled Ir@PS nano-catalyst (after 3rd Cycle) which clearly indicated
the aggregation or increase in the particle size of NPs and presence of Ir
metal after 3rd cycle respectively (Fig. S4, Supporting Information).
Mechanistically, reduction of nitroarenes to N-aryl hydroxyl amines
a
Reaction conditions: 1b-q (1 equiv.), Ir@PS (2 mol%), hydrazine hydrate (4
◦
b
c
equiv.), 85 C, PEG-400 (2 mL); isolated yields; reaction performed at room
temperature.
4

D. Bhattacherjee et al.
Molecular Catalysis 514 (2021) 111836
proceeds via nitrosobenzene intermediate. In order to prove such anal-
ogy, we have treated nitrosobenzene under standard reaction conditions
for N-aryl hydroxyl amine synthesis (Path B, Scheme 2). Moreover, the
reaction of nitrosobenzene with Ir@PS and hydrazine hydrate took place
at room temperature to afford corresponding hydroxyl amine along with
the formation of azoxybenzene and aniline.
Credit Author Statement
Dhananjay Bhattacherjee: Conceptualization, Methodology, Valida-
tion, Writing - Original Draft.
Shaifali: Investigation, Data Curation, Visualization, Formal
analysis.
Interestingly, we have observed that the dissociation of hydrazine
hydrate took place over catalyst surface only after addition of nitro-
arenes in PEG-400 solvent. Moreover, the PEG-400 played an important
role on dissolution of the liberated hydrogen into the reaction mixture
and thereby its absorption on catalytic surface.
Ajay Kumar: Data Curation, Resources, Writing - Review & Editing.
Grigory V. Zyryanov: Project administration, Writing - Review &
Editing.
Pralay Das: Supervision, Conceptualization, Project administration,
Writing- Reviewing and Editing.
On the basis of above observations and literature reports a plausible
mechanistic pathway for the semi- hydrogenation of nitroarenes to N-
arylhydroxylamine has drawn in the Scheme 2 [25, 28, 56-59]. Initially,
the hydrazine hydrate gets chemisorbed on the catalyst surface I which
in turn participates in the H-bonding with the nitro group of the sub-
strate via intermediate II. The non-covalent interaction between hy-
drazine hydrate and the nitroarenes over the catalytic surface might
Supplementary materials
Supplementary material associated with this article can be found, in
the online version, at doi:10.1016/j.mcat.2021.111836.
References
weakens the H
–
N bond of the hydrazine hydrate and facilitates its
and N
[
1] K. Shudo, T. Okamoto, Carcinogenic reactions. Arylamination with
decomposition to H
2
2
.
arylhydroxylamines, Tetrahedron Lett 21 (1973) 1839–1842, https://doi.org/
The liberated hydrogen gets chemisorbed onto the heterogeneous
surface along with the transient nitrosoarene intermediate III which
further allows the transfer hydrogenation process via intermediate IV to
obtain N-aryl hydroxylamine as final product (Scheme 2).
1
0.1016/S0040-4039(01)96253-7.
[2] K. Shudo, T. Ohta, T. Okamoto, Acid-catalyzed reactions of N-arylhydroxylamines
and related compounds with benzene. Iminium-benzenium ions, J. Am. Chem. Soc.
1
03 (1981) 645–653, https://doi.org/10.1021/ja00393a025.
[
3] T. Hiroshi, T.J. Ichi, H. Suguru, T. Keisuke, O. Yoshinori, Selective Aromatic N-
Substitution with N-(4-Tolyl)hydroxylamine by Addition of Polar Aprotic or
Diethereal Solvent, Eur. J. Org. Chem. 2003 (2003) 3920–3922, https://doi.org/
Conclusion
1
0.1002/ejoc.200200576.
[
[
4] E. Bamberger, Ber. Dtsch. Chem. Ges 27 (1894) 1347–1350, https://doi.org/
10.1002/cber.18940270229.
5] J.S. Yadav, B.V.S. Reddy, P. Sreedhar, Three-Component One-Pot Synthesis of
In summary, we have developed an efficient polystyrene stabilized
iridium NPs as heterogeneous catalyst for the semi-hydrogenation of
nitroarenes to N-aryl hydroxyl amines. The newly developed Ir@PS NPs
as catalyst was further characterized by SEM, TEM, HR-TEM, SAED
imaging techniques and finally by powder XRD analysis. The in situ
reduction of iridium salt to Ir (0) monitored by UV-Vis spectroscopy. The
catalyst was found to be highly selective for semi-hydrogenation of
nitroarenes using PEG-400 as environmentally benign solvent. A wide
range of functional groups and multiple bonds were well tolerated under
the present catalytic conditions. Moreover, the present method showed
an excellent region-selectivity for the reduction of dinitroarenes to N-
aryl hydroxyl amines. The prepared catalyst can be re-used for two cy-
cles and the catalyst shows reactivity up to five runs.
α
-Hydroxylamino Phosphonates using Ionic Liquids, Adv. Synth. Catal. 345 (2003)
5
64–567, https://doi.org/10.1002/adsc.200202209.
[6] P.M. Vyas, S. Roychowdhury, P.M. Woster, C.K. Svensson, Reactive oxygen species
generation and its role in the differential cytotoxicity of the arylhydroxylamine
metabolites of sulfamethoxazole and dapsone in normal human epidermal
keratinocytes, Biochem. Pharmacol. 70 (2005) 275–286, https://doi.org/10.1016/
j.bcp.2005.04.023.
[
7] C.K. Svensson, Do arylhydroxylamine metabolites mediate idiosyncratic reactions
associated with sulfonamides? Chem. Res. Toxicol. 16 (2003) 1035–1043, https://
doi.org/10.1021/tx034098h.
[8] A.D. McGill, W. Zhang, J. Wittbordt, J. Wang, H.B. Schlegel, P.G. Wang, Para-
Substituted N-nitroso-N-oxybenzenamine ammonium salts: a new class of redox-
sensitive nitric oxide releasing compounds, Bioorg. Med. Chem. 8 (2000) 405–412,
https://doi.org/10.1016/S0968-0896(99)00300-4.
[9] A.T. Balaban, R.E. Garfield, M.J. Lesko, W.A. Seitz, Synthesis and spectral data of
some new N-nitroso-N-phenylhydroxylamine (cupferron) derivatives, Org. Prep.
Proced. Int. 30 (1998) 439–446, https://doi.org/10.1080/00304949809355306.
10] D. Beaudoin, J.D. Wuest, Synthesis of N-arylhydroxylamines by Pd-catalyzed
coupling, Tetrahedron Lett. 52 (2011) 2221–2223, https://doi.org/10.1016/j.
tetlet.2010.12.034.
[
[
Declaration of Competing Interest
11] F. Li, J. Cui, X. Qian, R. Zhanga, Y. Xiao, Highly chemoselective reduction of
aromatic nitro compounds to the corresponding hydroxylamines catalysed by plant
cells from a grape (Vitis vinifera L.), Chem. Commun. (2005) 1901–1903, https://
doi.org/10.1039/B418675C.
The authors declare that they have no known competing financial
interests or personal relationships that could have appeared to influence
the work reported in this paper.
[
12] P.-.D. Ren, X.-.W. Pan, Q.-.H. Jin, Z.-.P. Yao, Reduction of Nitroarenes to N-
4 3
Arylhydroxylamines with KBH /BiCl System, Synth. Commun. 27 (1997)
3
497–3503, https://doi.org/10.1080/00397919708007070.
Acknowledgements
[13] P. Ren, T. Dong, S. Wu, Synthesis of N-arylhydroxylamines by antimony-catalyzed
reduction of nitroarenes, Synth. Commun. 27 (1997) 1547–1552, https://doi.org/
1
0.1080/00397919708006092.
We are grateful to the Director of CSIR-IHBT for providing the
necessary facilities during the course of this work. The authors thank the
CSIR, New Delhi for financial support as part of in-house project no.
MLP0203. We also thank AMRC, IIT Mandi, for the PXRD experiment.
Shaifali and AK thank the UGC and CSIR, New Delhi, for awarding fel-
lowships, and DB and GVZ thank the Russian Scientific Foundation
[
[
14] K. Yanada, H. Yamaguchi, H. Meguri, S. Uchida, Selenium-catalysed reduction of
aromatic nitro compounds to N-arylhydroxylamines, J. Chem. Soc., Chem.
Commun. (1986) 1655–1656, https://doi.org/10.1039/C39860001655.
15] M.S. Mourad, R.S. Varma, G.W. Kabalka, Reduction of α, β-unsaturated nitro
compounds with boron hydrides: a new route to N-substituted hydroxylamines,
J. Org. Chem. 50 (1985) 133–135, https://doi.org/10.1021/jo00201a030.
[16] H. Feuer, R.S. Bartlett, B.F. Vincent Jr., R.S. Anderson, Diborane Reduction of Nitro
Salts. A New Synthesis of N-Monosubstituted Hydroxylamines, J. Org. Chem. 30
(
Grant #20–73–10205), (Grant #19-73-10144) and Grants Council of
(
1965) 2880–2882, https://doi.org/10.1021/jo01020a002.
the President of the Russian Federation (Ref. # NSh-2700.2020.3).
[
17] H. Feuer, B.F. Vincent Jr., R.S. Bartlett, The reduction of oximes with diborane. A
new synthesis of N-monosubstituted hydroxylamines, J. Org. Chem. 30 (1965)
2
877–2880, https://doi.org/10.1021/jo01020a001.
[
[
18] H. Feuer, B.F. Vincent Jr., A Convenient Synthesis of N-Alkylhydroxylamines,
J. Am. Chem. Soc. 84 (1962) 3771–3772, https://doi.org/10.1021/ja00878a037.
19] Q.X. Shi, R.W. Lu, K. Jin, Z.X. Zhang, D.F. Zhao, Ultrasound-promoted highly
chemoselective reduction of aromatic nitro compounds to the corresponding N-
Author Contributions
The manuscript was written through contributions of all authors. All
authors have given approval to the final version of the manuscript.
4 3
arylhydroxylamines using zinc and HCOONH in CH CN, Chem. Lett. 35 (2006)
2
26–227, https://doi.org/10.1246/cl.2006.226.
‡These authors contributed equally.
5

D. Bhattacherjee et al.
Molecular Catalysis 514 (2021) 111836
[
[
20] S. Ung, A. Flgui `e res, A. Guy, C. Ferroud, Ultrasonically activated reduction of
substituted nitrobenzenes to corresponding N-arylhydroxylamines, Tetrahedron
Lett 46 (2005) 5913–5917, https://doi.org/10.1016/j.tetlet.2005.06.126.
21] M. Bartra, P. Romea, F. Urpi, J. Vílarrasa, A fast procedure for the reduction of
[41] A. Zanardi, J.A. Mata, E. Peris, One-Pot Preparation of Imines from Nitroarenes by
a Tandem Process with an Ir–Pd Heterodimetallic Catalyst, Chem. Eur. J. 16 (2010)
10502–10506, https://doi.org/10.1002/chem.201000801.
[42] C.-.Y. Wang, C.-.F. Fu, Y.-.H. Liu, S.-.M. Peng, S.-.T. Liu, Synthesis of iridium
pyridinyl N-heterocyclic carbene complexes and their catalytic activities on
reduction of nitroarenes, Inorg. Chem. 46 (2007) 5779–5786, https://doi.org/
10.1021/ic070330l.
azides and nitro compounds based on the reducing ability of Sn (SR)
3
-species,
Tetrahedron 46 (1990) 587–594, https://doi.org/10.1016/S0040-4020(01)85439-
9
.
[
[
22] S. Liu, Y. Wang, J. Jiang, Z. Jin, The selective reduction of nitroarenes to N-
arylhydroxylamines using Zn in a CO /H O system, Green Chem 11 (2009)
[43] G.-.Y. Fan, L. Zhang, H.-.Y. Fu, M.-.L. Yuan, R.-.X. Li, H. Chen, X.-.J. Li, Hydrous
zirconia supported iridium nanoparticles: an excellent catalyst for the
hydrogenation of haloaromatic nitro compounds, Catal Commun 11 (2010)
451–455, https://doi.org/10.1016/j.catcom.2009.11.021.
2
2
1
397–1400, https://doi.org/10.1039/B906283A.
23] F.M. Cordero, I. Barile, F. De. Sarlo, A. Brandi, The powerful effect of N-aryl
substitution in promoting the thermal rearrangement of 5-
[44] N.R. Guha, C.B. Reddy, N. Aggarwal, D. Sharma, A.K. Shil, P.Das Bandna, Solid-
Supported Rhodium(0) Nano-/Microparticles: an Efficient Ligand-Free
Heterogeneous Catalyst for Microwave-Assisted Suzuki–Miyaura Cross-Coupling
Reaction, Adv. Synth. Catal. 354 (2012) 2911–2915, https://doi.org/10.1002/
adsc.201200418.
[45] S. Ram, A.S.Chauhan Shaifali, A.K.Sharma Sheetal, P. Das, Polystyrene-Supported
Palladium (Pd@PS)-Catalyzed Carbonylative Annulation of Aryl Iodides Using
Oxalic Acid as a Sustainable CO Source for the Synthesis of 2-Aryl Quinazolinones,
Chem. Eur. J. 25 (2019) 14506–14511, https://doi.org/10.1002/
chem.201902776.
[46] C.B. Reddy, S. Ram, A. Kumar, R. Bharti, P. Das, Supported Palladium
Nanoparticles that Catalyze Aminocarbonylation of Aryl Halides with Amines
using Oxalic Acid as a Sustainable CO Source, Chem. Eur. J. 25 (2019) 4067–4071,
https://doi.org/10.1002/chem.201900271.
[47] S. Sharma, D. Bhattacherjee, P. Das, Supported Rhodium Nanoparticles Catalyzed
Reduction of Nitroarenes, Arylcarbonyls and Aryl/Benzyl Sulfoxides using
Ethanol/Methanol as In Situ Hydrogen Source, Adv. Synth. Catal. 360 (2018) 1–8,
https://doi.org/10.1002/adsc.201701609.
spirocyclopropaneisoxazolidines, Tetrahedron Lett 40 (1999) 6657–6660, https://
doi.org/10.1016/S0040-4039(99)01339-8.
[
[
[
[
[
24] I.D. Entwistle, T. Gilkerson, R.A.W. Johnstone, R.P. Telford, Rapid catalytic
transfer reduction of aromatic nitro compounds to hydroxylamines, Tetrahedron
3
4 (1978) 213–215, https://doi.org/10.1016/S0040-4020(01)93607-5.
25] (a)A.K. Shil, P. Das, Solid supported platinum (0) nanoparticles catalyzed chemo-
selective reduction of nitroarenes to N-arylhydroxylamines, Green Chem 15 (2013)
3
421–3428, https://doi.org/10.1039/C3GC41179F.
26] P.N. Rylander, I.M. Karpenko, G.R. Pond, Selectivity in hydrogenation over
platinum metal catalysts: nitroaromatics, Ann. N. Y. Acad. Sci. 172 (1970)
2
66–275, https://doi.org/10.1111/j.1749-6632.1970.tb34984.x.
27] S.L. Karwa, R.A. Rajadhyaksha, Selective catalytic hydrogenation of nitrobenzene
to phenylhydroxylamine, Ind. Eng. Chem. Soc. 26 (1987) 1746–1750, https://doi.
org/10.1021/ie00069a005.
28] D.V. Jawale, E. Gravel, C. Boudet, N. Shah, V. Geertsen, H. Li, I.N.N. Namboothiri,
E. Doris, Selective conversion of nitroarenes using a carbon nanotube–ruthenium
nanohybrid, Chem. Commun. 51 (2015) 1739, https://doi.org/10.1039/
C4CC09192B.
[48] C.B. Reddy, R. Bharti, S. Kumar, P. Das, Supported palladium nanoparticle
[
[
[
29] M. Tamura, K. Kon, A. Satsuma, K-i. Shimizu, Volcano-Curves for Dehydrogenation
catalyzed -alkylation of ketones using alcohols as alkylating agents, ACS Sustain
Chem Eng 5 (2017) 9683–9691, https://doi.org/10.1021/
acssuschemeng.7b00789.
α
of 2-Propanol and Hydrogenation of Nitrobenzene by SiO
Nanoparticles Catalysts As Described in Terms of a D-Band Model, ACS Catal 2
2012) 1904–1909, https://doi.org/10.1021/cs300376u.
30] S. Ozkar, R.G. Finke, Iridium(0) Nanocluster, Acid-Assisted Catalysis of Neat
Acetone Hydrogenation at Room Temperature: Exceptional Activity, Catalyst
Lifetime, and Selectivity at Complete Conversion, J. Am. Chem. Soc. 127 (2005)
2
-Supported Metal
(
[49] D. Liu, X. Chen, G. Xu, J. Guan, Q. Cao, B. Dong, Y. Qi, C. Li, X. Mu, Iridium
nanoparticles supported on hierarchical porous N-doped carbon: an efficient water-
tolerant catalyst for bio-alcohol condensation in water, Sci Rep 6 (2016) 21365,
https://doi.org/10.1038/srep21365.
[50] A. Goel, N. Rani, Effect of PVP, PVA and POLE surfactants on the size of iridium
nanoparticles, Open J Inorg Chem 2 (2012) 67–73, https://doi.org/10.4236/
ojic.2012.23010.
[51] M. Zahmakiran, Iridium nanoparticles stabilized by metal organic frameworks
(IrNPs@ ZIF-8): synthesis, structural properties and catalytic performance, Dalton
Trans 41 (2012) 12690–12696, https://doi.org/10.1039/C2DT31779F.
[52] S. Ghosh, M. Ghosh, C.N.R. Rao, Nanocrystals, nanorods and other nanostructures
of nickel, ruthenium, rhodium and iridium prepared by a simple solvothermal
procedure, Journal of Cluster Science 8 (2007) 97–111, https://doi.org/10.1007/
s10876-006-0085-6.
4
800–4808, https://doi.org/10.1021/ja0437813.
31] A. Minguzzi, C. Locatelli, O. Lugaresi, E. Achilli, G. Cappelletti, M. Scavini,
M. Coduri, P. Masala, B. Sacchi, A. Vertova, P. Ghigna, S. Rondinini, Easy
accommodation of different oxidation states in iridium oxide nanoparticles with
different hydration degree as water oxidation electrocatalysts, ACS Catal 5 (2015)
5
104–5115, https://doi.org/10.1021/acscatal.5b01281.
[
32] J.C. Hidalgo-Acosta, M.A. Mendez, M.D. Scanlon, H. Vrubel, V. Amstutz,
W. Adamiak, M. Opallo, H.H. Girault, Catalysis of water oxidation in acetonitrile
by iridium oxide nanoparticles, Chem. Sci 6 (2015) 1761–1769, https://doi.org/
1
0.1039/C4SC02196G.
[
[
33] H. Kobayashi, M. Yamauchi, H. Kitagawa, Finding hydrogen-storage capability in
iridium induced by the nanosize effect, J. Am. Chem. Soc. 134 (2012) 6893–6895,
https://doi.org/10.1021/ja302021d.
34] P. Das, P.P. Sarmah, B.J. Borah, L. Saikia, D.K. Dutta, Aromatic ring hydrogenation
catalysed by nanoporous montmorillonite supported Ir (0)-nanoparticle composites
under solvent free conditions, New J. Chem. 40 (2016) 2850, https://doi.org/
[53] J. Schneekoenig, W. Liu, T. Leischner, K. Junge, C. Schotes, C. Beier, M. Beller,
Application of Crabtree/Pfaltz-type iridium complexes for the catalyzed
asymmetric hydrogenation of an agrochemical building block, Org. Process Res.
Dev. 24 (2020) 443–447, https://doi.org/10.1021/acs.oprd.9b00466.
[54] A.N. Kim, A. Ngamnithiporn, E.R. Welin, M. Daiger, C. Grünanger, M.
D. Bartberger, S.C. Virgil, B.M. Stoltz, Iridium-Catalyzed Enantioselective and
Diastereoselective Hydrogenation of 1, 3-Disubstituted Isoquinolines, ACS Catal 10
(2020) 3241–3248, https://doi.org/10.1021/acscatal.0c00211.
1
0.1039/C5NJ03030G.
[
[
35] D. Chandra, D. Takama, T. Masaki, T. Sato, N. Abe, T. Togashi, M. Kurihara,
K. Saito, T. Yui, M. Yagi, Highly Efficient Electrocatalysis and Mechanistic
[55] C. Wang, S. Gong, Z. Liang, Y. Sun, R. Cheng, B. Yang, Y. Liu, J. Yang, F. Sun,
Ligand-promoted iridium-catalyzed transfer hydrogenation of terminal alkynes
with ethanol and its application, ACS Omega 4 (2019) 16045–16051, https://doi.
org/10.1021/acsomega.9b02191.
x y
Investigation of Intermediate IrO (OH) Nanoparticle Films for Water Oxidation,
ACS Catal 6 (2016) 3946–3954, https://doi.org/10.1021/acscatal.6b00621.
36] Y. Motoyama, M. Taguchi, N. Desmira, S.-.H. Yoon, I. Mochida, H. Nagashima,
Chemoselective Hydrogenation of Functionalized Nitroarenes and Imines by Using
Carbon Nanofiber-Supported Iridium Nanoparticles, Chem. Asian J. 9 (2014)
[56] N.R. Guha, D. Bhattacherjee, P. Das, Solid supported rhodium(0) nanoparticles: an
efficient catalyst for chemo- and regio-selective transfer hydrogenation of
nitroarenes to anilines under microwave irradiation, Tetrahedron Lett 55 (2014)
2912–2916, https://doi.org/10.1016/j.tetlet.2014.03.047.
7
1–74, https://doi.org/10.1002/asia.201301184.
[
[
[
[
37] J. Wang, D. Ge, X. Cao, M. Tang, Y. Pan, H. Gu, A facile synthesis of Pt@ Ir zigzag
bimetallic nanocomplexes for hydrogenation reactions, Chem. Commun. 51 (2015)
[57] H. Tian, J. Zhou Y. Li, Y. Wang, L. Liu, Y. Ai, Z.-.N. Hu, J. Li, R. Guo, Z. Liu, H-
b. Sun, Q. Liang, Rh Catalyzed Selective Hydrogenation of Nitroarenes under Mild
Conditions: understanding the Functional Groups Attached to the Nanoparticles,
ChemCatChem 11 (2019) 5543–5552, https://doi.org/10.1002/cctc.201901491.
[58] P. Lara, K. Philippot, The hydrogenation of nitroarenes mediated by platinum
nanoparticles: an overview, Catal. Sci. Technol. 4 (2014) 2445–2465, https://doi.
org/10.1039/C4CY00111G.
[59] H.-.U. Blaser, H. Steiner, M. Studer, Selective catalytic hydrogenation of
functionalized nitroarenes: an update, ChemCatChem 1 (2009) 210–221, https://
doi.org/10.1002/cctc.200900129.
9
216, https://doi.org/10.1039/C5CC02905H.
38] S. Chen, G. Lu, C. Cai, Iridium-catalyzed transfer hydrogenation of nitroarenes to
anilines, New J. Chem. 39 (2015) 5360–5365, https://doi.org/10.1039/
C5NJ00917K.
39] Md.J. Sharif, P. Maity, S. Yamazoe T. Tsukuda, Selective hydrogenation of
nitroaromatics by colloidal iridium nanoparticles, Chem. Lett. 42 (2013)
1
023–1025, https://doi.org/10.1246/cl.130333.
40] S. Sabater, J.A. Mata, E. Peris, Dual Catalysis with an IrIII–AuI Heterodimetallic
Complex: reduction of Nitroarenes by Transfer Hydrogenation using Primary
Alcohols, Chem. Eur. J. 18 (2012) 6380–6385, https://doi.org/10.1002/
chem.201103657.
6