Electronic Supplementary Material (ESI) for RSC Advances.
This journal is © The Royal Society of Chemistry 2014
Supporting Information
For
A Hydroquinone Based Palladium Catalyst for Room
Temperature Nitro reduction in water
Alok Kumar,‡ Kallol Purkait,‡ Suman Kr. Dey, Amrita Sarkar and Arindam
Mukherjee*a
Department of Chemical Sciences, Indian Institute of Science Education and Research
Kolkata, Mohanpur-741252, India,
Email: [email protected]
‡
Both the authors contributed equally to this work
1
Contents
Experimental Section .............................................................................................................................. 4
Materials and instrumentation ........................................................................................................... 4
Synthesis of 3,5-dimethylpyrazole ...................................................................................................... 4
Synthesis of ligand H2L ........................................................................................................................ 4
Synthesis of complex 1........................................................................................................................ 5
X-ray crystallography .......................................................................................................................... 5
Table S1. Selected crystallographic parameters of 1.2H2O ............................................................ 6
Table S2. Selected bond lengths (Å) and angles (°) for 1.2H2O ....................................................... 6
General catalytic nitro reduction for aryl nitro substrates used for optimization reactions ............. 7
Optimization of complex 1 catalysed reduction of nitro arene reaction. .......................................... 7
Table S3. Screening of solvent for aryl nitro reduction catalyzed by 1.a ........................................ 7
Table S4. Screening of temperature for aryl nitro reduction of Nitrobenzene catalyzed by 1.a .... 7
Table S5. Screening of catalyst loading for aryl nitro reduction of Nitrobenzene catalyzed by 1.a 8
Table S6. Catalytic ability of complex 1 over few other common Pd-compounds.a ....................... 8
Representative procedure of catalytic reduction of nitroarenes substrates ..................................... 8
General catalytic Suzuki-Miyaura cross coupling reaction for aryl halide substrates with phenyl
boronic acid used for optimization reactions ..................................................................................... 8
Optimization of complex 1 catalysed Suzuki-Miyaura cross coupling reaction.................................. 9
Table S7. Optimization of solvent for Suzuki-Miyaura cross coupling reaction of 4-bromo anisole
with phenylboronic acid catalyzed by 1.a ....................................................................................... 9
Table S8. Optimization of base for Suzuki-Miyaura cross coupling reaction of 4-bromo anisole
with phenylboronic acid catalyzed by 1.a ....................................................................................... 9
Table S9. Screening of catalyst loading for Suzuki-Miyaura cross coupling reaction of 4bromoanisole with phenylboronic acid catalyzed by 1.a .............................................................. 10
Table S10. Screening of temperature for Suzuki-Miyaura cross coupling reaction of 4bromoanisole with phenylboronic acid catalyzed by 1.a .............................................................. 10
Scheme S1. Proposed catalytic cycle for Suzuki-Miyaura cross coupling reaction by complex 1 in
presence of base. The mechanistic pathway is similar to that known in literature.4 ................... 11
Table S11. Suzuki-Miyaura cross coupling reaction of aryl halides with Phenylboronic acid.a .... 11
General procedure for Syntheses of biaryl amines from nitro substituted aryl halides and
phenylboronic acid in one pot using catalyst 1 ................................................................................ 12
Scheme S2. Proposed dehalogenation and nitroarene reduction mechanism by catalyst 1 using
1-bromo-4-nitrobenzene as a model substrate. The complex is dipositively charged when the
palladium is +2 oxidation state. .................................................................................................... 13
Figure S1. 1H NMR spectrum of the reaction between iodobenzene (0.018mmol) and NaBH4 (0.018
mmol) in presence of catalyst 1 (0.003 mmol) in methanol-D4 at 25 °C. More than 90% conversion
2
has occurred within 4-5 min since the spectra shows presence of only ca. 6% substrate
(iodobenzene). .................................................................................................................................. 14
Figure S2. 1H NMR spectrum of reaction mixture of iodobenzene (0.018mmol) and NaBH4 (0.018
mmol) in presence of 1 (0.003 mmol, to have sufficient concentration in 1H NMR). Solvent is
methanol-D4, spectrum recorded at 25 °C and only the relevant region was scanned for better
signal to noise ratio. .......................................................................................................................... 14
Figure S3. 1H NMR of 0.03 mmol of 4-nitrobenzonitrile, 0.24 mmol NaBH4, 0.25 mol% catalyst 1
in D2O. 1,4-dioxane was used for reference. ............................................................................... 15
1
H and 13C NMR data of Suzuki-Miyaura product ............................................................................. 15
4-methoxybiphenyl. ...................................................................................................................... 15
4-methylbiphenyl .......................................................................................................................... 15
4-acetylbiphenyl............................................................................................................................ 15
4-nitrobiphenyl. ............................................................................................................................ 15
4-cyanobiphenyl............................................................................................................................ 16
2-phenylpyridine. .......................................................................................................................... 16
3-nitrobiphenyl. ............................................................................................................................ 16
1
H and 13C NMR data of nitro reduction product.............................................................................. 16
Aniline. .......................................................................................................................................... 16
4-aminophenol. ............................................................................................................................. 16
4-cyanoaniline. .............................................................................................................................. 16
4-(pyridin-4-ylmethyl)aniline. ....................................................................................................... 16
4-chloro-1,2-diaminobenzene. ..................................................................................................... 16
1
H and 13C NMR data of tandem type reaction product ................................................................... 16
4-aminobiphenyl. .......................................................................................................................... 16
3-aminobiphenyl. .......................................................................................................................... 16
References. ........................................................................................................................................... 32
3
Experimental Section
Materials and instrumentation
Palladium chloride was purchased from Precious metal online, Australia. All the other chemicals for
catalysis were purchased from sigma-aldrich, Spectrochem and SRL (India) and used without any
further purification. The solvents were dried or distilled prior to use.1 HPLC grade water and ethanol
from spectrochem, India were used for catalysis. For the characterization of the ligand, metal
complexes and all products of the catalytic reaction we used 400 MHz JEOL NMR spectrophotometer
or 500 MHz BRUKER spectrophotometer. The chemical shifts are reported in parts per million
(ppm). All NMR data were collected at room temperature (25 °C). Melting points and decomposition
temperatures of the compounds were measured in triplicate with one end sealed capillaries using
SECOR India melting point apparatus and the uncorrected values are reported. UV-Visible
measurements were done using Perkin Elmer lambda 35 spectrophotometer. FT-IR spectra were
recorded using Perkin-Elmer SPECTRUM RX I spectrometer in KBr pellets. Perkin -Elmer 2400
series II CHNS/O analyzer was used for elemental analysis. Electro-spray ionization mass spectra
were recorded by +ve mode electrospray ionization, using a Q-Tof micro™ (Waters) mass
spectrometer. Single crystal X-ray data was collected on an Agilent Technologies Supernova (Oxford
Diffraction) diffractometer. The recrystallization yields of isolated ligand and metal complexes,
isolated products of catalysis reaction after column chromatography are reported. All the compounds,
ligand and metal complex were dried in vacuum and stored in desiccators under dark.
Synthesis of 3,5-dimethylpyrazole
The compound was synthesized by dropwise addition of hydrazine hydrate on acetylacetone at 0 °C
and continues the stirring for half an hour. A white coloured product is immediately separated out
from the solution. After 0.5 h white solid was collected by filtration and purified by washing with
petroleum benzene. Yield (90%),1H NMR (400 MHz, CDCl3, 25°C): δ 10.92 (br. s, 1H, NH), 5.81 (s,
1H, ArH), 2.27 (s, 6H, CH3). 13C NMR (100 MHz, CDCl3, 25°C): δ 144.36, 104.08, 12.24.
Synthesis of ligand H2L
Compound H2L was synthesized by refluxing p-benzoquinone with 3,5-dimethylpyrazole in 1,4dioxane under nitrogen atmosphere as in literature procedure.2 The product was further purified by
silica gel (60-120mesh) column chromatography using dichloromethane and ethyl acetate 7:3
mixtures. Yield (25%), Mp. 276-281 °C. 1H NMR (500 MHz, CDCl3, 25°C): δ 7.25 (s, 2H, OH), 7.04
(s, 2H, ArH), 5.89 (s, 2H, ArH), 2.28 (s, 6H, 2CH3), 1.67 (s, 6H, 2CH3). 13C NMR (125 MHz, CDCl3,
25°C): δ 151.20, 145.74, 143.76, 120.46, 118.06, 107.02, 13.31, 10.72. ESI-MS (Methanol) m/z
(calc.): 299.20 (299.15) [C16H19N4O2+] Elemental analysis: Anal. Calcd. for C16H18N4O2: C, 64.41; H,
4
6.08; N, 18.78. Found: C, 64.36; H, 6.11; N, 18.53. UV-vis λmax/nm (ε/dm3 mol−1 cm−1) in CH3CN:
306 (4510), 222 (10025), 206 (9727). FT-IR (KBr) (νmax/cm−1): 2933, 2624, 1557, 1499, 1226.
Synthesis of complex 1
0.298g (1.0 mmol) of H2L with 0.259g (1.0 mmol) of PdII(MeCN)2Cl2 were dissolved in acetonitrile
and heated to reflux under dark. After 16h the reaction mixture was cooled to room temperature and
concentrated on a rotary evaporator to get precipitation of the metal complex. The precipitation was
collected by filtration and washed with diethyl ether, which was further purified by crystallisation
from acetonitrile and ethyl acetate 5:2 mixture solution by slow evaporation method. Yield (95%),
Mp. (decomp.) >300 °C. 1H NMR (500 MHz, DMSO-d6, 25°C): δ 10.41 (s, 2H, OH), 7.32 (s, 2H,
ArH), 6.13 (s, 2H, ArH), 2.52 (s, 6H, 2CH3), 2.06 (s, 6H, 2CH3) (Figure S4). 13C NMR (125 MHz,
DMSO-d6, 25°C): δ 180.27, 154.53, 147.02, 137.03, 136.82, 110.16, 14.06, 11.63 (Figure S5), ESIMS (Methanol) m/z (calc.): 403.14 (403.04) [C16H17N4O2Pd+], Elemental analysis: Anal. calcd. for
C16H18Cl2N4O2Pd: C, 40.4; H, 3.18; N, 11.78. Found: C 40.7 H, 3.35, N, 11.81. UV-vis λmax/nm
(ε/dm3 mol−1 cm−1) in CH3CN: 308 (9227). FT-IR (KBr) (νmax/cm−1): 3360, 2362, 1554, 1507, 1294.
X-ray crystallography
A good quality brick red coloured single crystal was obtained from acetonitrile solution using the
method of slow evaporation. Single crystal X-ray diffraction study was carried out on the Agilent
Technologies Supernova diffractometer and measured at 300 K using Mo-Kα radiation (0.71073 Å).
An empirical multi-scan absorption correction was performed using spherical harmonics,
implemented in SCALE3 ABSPACK scaling algorithm. The integral values (from the instrument)
were refined in apex2 software where all non-hydrogen atoms were refined anisotropically by full
matrix least-squares on F2 to get the structure. The hydrogen atoms were calculated and fixed using
SHELXL-97 after hybridization of all non hydrogen atoms.3 Selected crystallographic parameters are
enlisted in Table S1. The crystallographic data of 1 has been deposited at the Cambridge
Crystallographic Data Centre as supplementary publication CCDC 996012. These data can be
obtained
free
of
charge
from
the
Cambridge
Crystallographic
Data
Centre
via
www.ccdc.cam.ac.uk/data_request/cif.
5
Table S1. Selected crystallographic parameters of 1.2H2O
1.2H2O
Empirical formula
C16H20Cl2N4O4Pd
Formula weight
509.64
Temperature (K)
100(2)
Wavelength(Å)
0.71073
Crystal system
Orthorhombic
space group
Cmc2(1)
a (Å)
16.3889(10)
b (Å)
8.8163(3)
c (Å)
14.1318(4)
 (deg.)
90
 (deg.)
90
γ (deg.)
90
Volume (Å3)
2041.90(15)
Z, Calculated density (Mg/m3)
4, 1.651
F(000)
1120
Reflections collected / unique
2816 / 1921 [R(int) = 0.0266]
Max. and min. transmission
1.00000 and 0.93118
Goodness-of-fit on F2
1.072
Final R indices [I>2σ(I)]
R1 = 0.0342, wR2 = 0.0752
R indices (all data)
R1 = 0.0386, wR2 = 0.0798
Table S2. Selected bond lengths (Å) and angles (°) for 1.2H2O
Pd(1)-N(1)
2.024
N(1)-Pd(1)-N(1A)a
85.5
Pd(1)-Cl(1)
2.2827
N(1)-Pd(1)-Cl(1)
91.66
Cl(1)-Pd(1)-Cl(1A)a 91.20
a
A = -x+1, y, z
6
General catalytic nitro reduction for aryl nitro substrates used for
optimization reactions
Nitro arene (1.0mmol), NaBH4 (4.0 mmol) were dissolved in10ml of ethanol followed by the addition
of 4.7 mg (1.0 mol %) of catalyst. After that the reaction mixture was refluxed according to the reflux
temperature of solvent under dark and completion was monitored by silica gel thin layer
chromatography. The solvent was evaporated under reduced pressure and re-dissolved in ethyl acetate
and washed two times with water. Further the product was purified by silica column chromatography
using 20% dichloromethane in petroleum benzene.
Optimization of complex 1 catalysed reduction of nitro arene reaction.
Table S3. Screening of solvent for aryl nitro reduction catalyzed by 1.a
NO2
NH2
Pd-catalyst
NaBH4 , Solvent
reflux
Entry
Solvent
Isolated Yield (%)b
Time (min)
1
Ethanol
>99
15
2
H2O
>99
15
a
Reaction conditions: 1.0 mmol nitrobenzene, 4.0 mmol sodium borohydride, 4.7 mg (1 mol %)
b
catalyst, solvent, reflux. Isolated yields were reported after performed column chromatography.
Table S4. Screening of temperature for aryl nitro reduction of Nitrobenzene catalyzed by 1.a
NO2
NH2
Pd-catalyst
NaBH4 , water , T oC
Entry
Temperature(T oC)
Isolated Yield (%)b
Time (min)
1
85
>99
15
2
60
>99
15
3
27
>98
20
a
Reaction conditions: 1.0 mmol nitrobenzene, 4.0 mmol sodium borohydride, water , 4.7 mg (1 mol
b
%) catalyst, T °C. Isolated yield were reported after column chromatography.
7
Table S5. Screening of catalyst loading for aryl nitro reduction of Nitrobenzene catalyzed by 1.a
NO2
NH2
Pd-catalyst
NaBH4 , water, 27 oC
a
b
Entry
Catalyst Loading
(mol %)
Isolated Yield (%)b
Time (min)
1
1.0
>99
20
2
0.5
>99
20
3
0.25
>99
25
Reaction conditions: 1.0 mmol nitrobenzene, 4.0 mmol Sodium borohydride, catalyst 1, water, 27°C.
Isolated yields were reported after column chromatography.
Table S6. Catalytic ability of complex 1 over few other common Pd-compounds.a
NO2
NC
Pd-catalyst
NH2
NaBH4 , ethanol, NC
27oC
Entry
Catalyst
Catalyst loading
(mol % )
Isolated Yield
(%)[b]
Time (h)b
1
2
3
4
Pd(OAc)2
PdCl2
Pd(MeCN)2Cl2
1
1.0
1.0
1.0
0.25
<30
<20
<30
>99
6
6
6
0.17
a
Reaction conditions: 1.0 mmol nitroarene, 4.0 mmol Sodium borohydride, catalyst 1, ethanol, 27°C.
Isolated yields were reported after column chromatography.
b
Representative procedure of catalytic reduction of nitroarenes substrates
1.0 mmol of nitroarene dissolved in 10ml of water followed by 0.152 g (4.0 mmol) NaBH4 and 1.2
mg (0.25 mol %) 1, were added to the reaction mixture at 27 °C and stirred vigorously. The
completion of the reaction was monitored by silica thin layer chromatography. After completion, the
reaction mixture was dried under reduced pressure and further purified by short silica column
chromatography (60-120 mesh) using proper ratio of dichloromethane in petroleum benzene as eluent.
The pure product was stored in desiccator under dark.
General catalytic Suzuki-Miyaura cross coupling reaction for aryl halide
substrates with phenyl boronic acid used for optimization reactions
Aryl halide (1.0 mmol), phenylboronic acid (1.5 mmol), base (3.0 mmol) and 2.3 mg (0.5 mol %) of
catalyst (complex 1) were kept in a single neck round bottom flask followed by 10ml solvent was
added to it. Now the reaction was performed at reflux temperature. After completion of the reaction,
8
the reaction mixture was dried under reduced pressure. Dissolve the reaction mixture in
dichloromethane and washed two times with water. The organic layer was dried over Na2SO4 and
purified through a short column chromatography (silica gel 60-120 mesh) using the appropriate
ratio of petroleum ether and dichloromethane to get pure biaryl.
Optimization of complex 1 catalysed Suzuki-Miyaura cross coupling
reaction
Table S7. Optimization of solvent for Suzuki-Miyaura cross coupling reaction of 4-bromo
anisole with phenylboronic acid catalyzed by 1.a
Br
+
OH
B
OH
Pd-cat (0.5mol%)
K2CO3, Solvent, reflux
O
O
Entry
Solvent
Isolated Yield (%)b
Time (h)
1
H2O
< 10
3.0
2
Ethanol
> 99
2.0
3
Dichloromethane
22
3.0
4
Toluene
48
3.5
5
1,4-Dioxane
26
3.5
6
Acetonitrile
< 10
3.5
a
Reaction conditions: 1.0 mmol 4-bromoanisole, 1.5 mmol phenylboronic acid, 0.5 mol% catalyst 1, 3
b
mmol K2CO3, solvent, reflux. Isolated yields were reported after column chromatography
Table S8. Optimization of base for Suzuki-Miyaura cross coupling reaction of 4-bromo anisole
with phenylboronic acid catalyzed by 1.a
Br
+
OH
B
OH
Pd-cat (0.5 mol%)
base, ethanol, reflux
O
O
Entry
Base
Isolated Yield (%)b
Time (h)
1
K2CO3
>99
2.0
2
Cs2CO3
94
3.0
3
NaOMe
75
3.0
4
Et3N
40
3.0
5
KOH
65
3.0
a
Reaction conditions: 1 mmol 4-bromoanisole, 1.5 mmol phenylboronic acid, 0.5 mol% catalyst 1, 3
b
mmol base, ethanol, reflux. Isolated yields were reported after column chromatography
9
Table S9. Screening of catalyst loading for Suzuki-Miyaura cross coupling reaction of 4bromoanisole with phenylboronic acid catalyzed by 1.a
Br
+
OH
B
OH
Pd-cat
K2CO3, ethanol, reflux
O
O
Entry
Catalyst Loading
(mol %)
Isolated Yield (%)b
Time (h)
1
0.5
>99
2.0
2
0.25
>99
2.5
3
0.1
54
3.0
a
Reaction conditions: 1 mmol 4-bromoanisole, 1.5 mmol phenylboronic acid, catalyst 1, 3 mmol
b
K2CO3, ethanol, reflux. Isolated yields were reported after performed column chromatography.
Table S10. Screening of temperature for Suzuki-Miyaura cross coupling reaction of 4bromoanisole with phenylboronic acid catalyzed by 1.a
Br
+
OH
B
OH
Pd-cat (0.25 mol %)
K2CO3, T oC
O
°
O
b
Entry
Temperature (T C)
Isolated Yield (%)
Time (h)
1
80
>99
2.5
2
27
>99
4.5
a
Reaction conditions: 1.0 mmol 4-bromoanisole, 1.5 mmol phenylboronic acid,0.25 mol% catalyst 1,
b
3.0 mmol K2CO3, ethanol. Isolated yields were reported after column chromatography.
Representative procedure for Suzuki-Miyaura cross coupling reaction
Aryl halide (1.0 mmol), phenylboronic acid (1.5 mmol), potassium carbonate (3.0 mmol) and 1.2 mg
(0.25 mol %) of catalyst (complex 1) were kept in a single neck round bottom flask followed by
which 10ml ethanol was added to it. Now the reaction was performed at 27 °C. After completion of
the reaction, the reaction mixture was dried under reduced pressure and re-dissolved in
dichloromethane then washed for two times with water. The organic layer was dried over Na2SO4 and
purified through a short column chromatography (silica gel 60-120 mesh) using the appropriate ratio
of petroleum ether and dichloromethane to get the pure biaryl.
10
HO
OH
N
N
N
N
Pd II
Cl
Cl
O
Ar'
O
N
N
X
N
N
Pd 0
Reductive Elimination
O
Oxidative Addition
O
N
N
O
N
N
O
N
N
Pd II
Ar'
N
N
Pd II
X
O
O
K2CO 3
B(CO3)2(OH)2
N
N
OH
B
OH
Transmetallation
Ar'
N
N
KCl
Pd II
OCO2
Scheme S1. Proposed catalytic cycle for Suzuki-Miyaura cross coupling reaction by complex 1
in presence of base. The mechanistic pathway is similar to that known in literature.4
Table S11. Suzuki-Miyaura cross coupling reaction of aryl halides with Phenylboronic acid.a
OH
B
OH
ArX +
Entry
Substrate (ArX)
Product
Ar
1(0.25mol%)
Isolated Yieldb (%)
Time (h)
Br
1
H3COC
98
2.3
95
4.5
H3COC
Br
2
H3CO
H 3CO
11
Cl
3c
NC
43
20
40
22
96
5.1
>99
1.2
>99
1.2
>99
1.0
98
2.2
98
2.5
NC
Cl
4c
H3CO
H 3CO
Br
5
N
N
I
6
H3CO
H3CO
I
7
H3C
H3C
I
8
NO2
NO2
Br
9
O2N
O2N
Br
10
NC
NC
a
Reaction conditions: 1.0 mmol aryl halide, 1.5 mmol phenylboronic acid, 0.25 mol% catalyst 1, 3.0
b
c
mmol K2CO3, ethanol, 27 °C. Isolated yields were reported after column chromatography. 2 mol%
catalyst 1, 3.0 mmol K2CO3, ethanol, 80 °C
General procedure for Syntheses of biaryl amines from nitro substituted
aryl halides and phenylboronic acid in one pot using catalyst 1
1.0 mmol of nitro substituted aryl halide, 1.5 mmol phenylboronic acid, 3.0 mmol K 2CO3 were taken
in a single neck round bottom flask followed by addition of 15 ml of ethanol and 1.2 mg (0.25 mol %)
of catalyst at room temperature. The completion of the reaction was monitored by silica gel thin layer
chromatography. After that immediately 0.152 g (4.0 mmol) NaBH4 was added and stirred for another
1 h under dark. The solvent of the reaction mixture was evaporated under reduced pressure and the
residues redissolved in dichloromethane, washed two times with water. Finally the product was
purified by short silica (60-120 mesh) column chromatography using dichloromethane and petroleum
benzene mixture. The pure products were isolated and stored in desiccator under dark.
12
HO
OH
N
N
N
N
PdII
Cl
Cl
NO2
O
O
N
N
Br
N
N
Pd0
HO
O
N N
N N
Pd
O2N
0
N N
N N
O
O2N
N N
PdII
Br
N N
O
N N
PdII
H
N N
O
OH
O
NO2
O
N N
+
2H , 2e
O
-
PdII
N N
NaBH4
NaBH4
O
NH2
NO
+ H2O
H2O +
O
O
NaBH4
PdII
N N
2H+, 2e-
II
Pd
N N
2H+, 2e-
O
NHOH
N
N
N
N Pd0
O
N N
N N
Pd0
PdII
N N
HO
O
O
OH
N N
O
N
O
N
N
N PdII
OH
HO
N
N
N
N PdII
NaBH4
Scheme S2. Proposed dehalogenation and nitroarene reduction mechanism by catalyst 1 using
1-bromo-4-nitrobenzene as a model substrate. The complex is dipositively charged when the
palladium is +2 oxidation state.
13
Figure S1. 1H NMR spectrum of the reaction between iodobenzene (0.018mmol)
and NaBH4 (0.018 mmol) in presence of catalyst 1 (0.003 mmol) in methanol-D4
at 25 °C. More than 90% conversion has occurred within 4-5 min since the
spectra shows presence of only ca. 6% substrate (iodobenzene).
Figure S2. 1H NMR spectrum of reaction mixture of iodobenzene (0.018mmol)
and NaBH4 (0.018 mmol) in presence of 1 (0.003 mmol, to have sufficient
concentration in 1H NMR). Solvent is methanol-D4, spectrum recorded at 25 °C
and only the relevant region was scanned for better signal to noise ratio.
14
Figure S3. 1H NMR of 0.03 mmol of 4-nitrobenzonitrile, 0.24 mmol NaBH4, 0.25 mol% catalyst 1
in D2O. 1,4-dioxane was used for reference.
1H
and 13C NMR data of Suzuki-Miyaura product
4-methoxybiphenyl. 1H NMR (CDCl3, 400 MHz, 25 °C)  7.55 (m, 4H, ArH), 7.43 (m, 2H, ArH),
7.31 (m, 1H, ArH), 6.99 (m, 2H, ArH), 3.86 (s, 3H, CH3) (Figure S6). 13C NMR (CDCl3, 100 MHz,
25 °C)  159.25, 140.94, 133.89, 128.85, 128.29, 126.87, 126.78, 114.31, 55.46 (Figure S7).
4-methylbiphenyl. 1H NMR (CDCl3, 400 MHz, 25 °C)  7.60 (d, J = 9.44 Hz, 2H, ArH), 7.52 (d, J
= 7.6 Hz, 2H, ArH), 7.4 (m, 2H, ArH), 7.35 (m, 1H, ArH), 7.27 (m, 2H, ArH), 2.43 (s, 3H, CH3)
(Figure S8). 13C NMR (CDCl3, 100 MHz, 25 °C)  141.28, 138.47, 137.15, 129.61, 128.84, 127.10,
21.24 (Figure S9).
4-acetylbiphenyl. 1H NMR (CDCl3, 400 MHz, 25 °C)  8.02 (d, J = 8.4 Hz, 2H, ArH), 7.68 (d, J =
8.4 Hz, 2H, ArH), 7.61 (m, 2H, ArH), 7.47 (m, 2H, ArH), 7.42 (m, 1H, ArH), 2.64 (s, 3H, CH3)
(Figure S10). 13C NMR (CDCl3, 100 MHz, 25 °C)  197.97, 145.90, 139.96, 135.92, 129.07, 129.08,
128.36, 127.38, 127.35, 26.81 (Figure S11).
4-nitrobiphenyl. 1H NMR (CDCl3, 400 MHz, 25 °C)  8.28 (d, J = 9.16 Hz, 2H, ArH), 7.72 (d, J =
8.4 Hz, 2H, ArH), 7.62 (m, 2H, ArH), 7.46 (m, 3H, ArH) (Figure S12). 13C NMR (CDCl3, 100 MHz,
25 °C)  147.75, 147.17, 138.87, 129.28, 129.04, 127.92, 127.5, 124.23 (Figure S13).
15
4-cyanobiphenyl. 1H NMR (CDCl3, 400 MHz, 25 °C)  7.67 (m, 4H, ArH), 7.58(m, 2H, ArH), 7.48
(m, 2H, ArH), 7.42 (m, 1H, ArH) (Figure S14). 13C NMR (CDCl3, 100 MHz, 25 °C)  145.79, 139.28,
132.72, 129.24, 128.79, 127.86, 127.35, 119.1, 111 (Figure S15).
2-phenylpyridine. 1H NMR (CDCl3, 400 MHz, 25 °C)  8.70 (m, 1H, ArH), 7.99 (m, 2H, ArH),
7.73 (m, 2H, ArH), 7.50 (m, 3H, ArH), 7.23 (m, 1H, ArH) (Figure S16). 13C NMR (CDCl3, 100 MHz,
25 °C)  157.6, 149.77, 139.49, 136.91, 129.08, 128.87, 127.04, 122.24, 120.74 (Figure S17).
3-nitrobiphenyl. 1H NMR (CDCl3, 500 MHz, 25 °C)  8.46 (m, 1H, ArH), 8.19 (m, 1H, ArH), 7.9
(m, 1H, ArH), 7.64-7.61 (m, 3H, ArH), 7.52-7.43 (m, 3H, ArH) (Figure S18). 13C NMR (CDCl3, 125
MHz, 25 °C)  148.88, 143.03, 138.82, 133.19, 129.85, 129.31, 128.68, 127.31, 122.18, 122.11
(Figure S19).
1H
and 13C NMR data of nitro reduction product
Aniline. 1H NMR (CDCl3, 400 MHz, 25 °C)  7.16 (m, 2H, ArH), 6.77 (m, 1H, ArH), 6.69 (m, 2H,
ArH), 3.35 (br. s, 2H, NH2). (Figure S20). 13C NMR (CDCl3, 100 MHz, 25 °C)  146.41, 129.41,
118.73, 115.26 (Figure S21).
4-aminophenol. 1H NMR (DMSO-D6, 400 MHz, 25 °C)  6.45 (d, J = 8.56 Hz, 2H, ArH), 6.38 (d, J
= 8.56 Hz, 2H, ArH), 4.35 (br. s, 2H, NH2). (Figure S22). 13C NMR (DMSO-D6, 100 MHz, 25 °C) 
149.10, 141.12, 115.98, 115.66. (Figure S23).
4-cyanoaniline. 1H NMR (CDCl3, 400 MHz, 25 °C)  7.41 (d, J = 8.36 Hz, 2H, ArH), 6.62 (d, J =
11.48 Hz, 2H, ArH), 4.13 (br. s, 2H, NH2). (Figure S24). 13C NMR (CDCl3, 100 MHz, 25 °C) 
150.45, 133.96, 120.20, 114.58, 100.50. (Figure S25).
4-(pyridin-4-ylmethyl)aniline. 1H NMR (CDCl3, 500 MHz, 25 °C)  8.46 (d, J = 4.56 Hz, 2H,
ArH), 7.10 (d, J = 4.56 Hz, 2H, ArH), 6.94 (d, J = 7.64 Hz, 2H, ArH), 6.63 (d, J = 8.4 Hz, 2H, ArH),
3.86 (s, 2H, CH2), 2.92 (br. s, 2H, NH2). (Figure S26). 13C NMR (CDCl3, 125 MHz, 25 °C) 151.37,
149.28, 145.01, 129.81, 128.59, 124.17, 115.38, 40.40. (Figure S27).
4-chloro-1,2-diaminobenzene. 1H NMR (CDCl3, 500 MHz, 25 °C)  6.67 (d, J = 2.5 Hz, 1H,
ArH), 6.66 (m, 1H, ArH), 6.65 (d, J = 8.5 Hz, 1H, ArH), 3.23 (br. s, 1H, NH2). (Figure S28). 13C
NMR (CDCl3, 125 MHz, 25 °C)  136.25, 133.18, 124.94, 119.74, 117.67, 116.37. (Figure S29).
1H
and 13C NMR data of tandem type reaction product
4-aminobiphenyl. 1H NMR (CDCl3, 400 MHz, 25 °C)  7.34 (m, 5H, ArH), 7.53 (m, 4H, ArH).
(Figure S30). 13C NMR (CDCl3, 100 MHz, 25 °C) 144.79, 129.58, 129.06, 123.17, 120.52, 116.25,
115.47, 115.26. (Figure S31).
3-aminobiphenyl. 1H NMR (CDCl3, 500 MHz, 25 °C)  7.56 (m, 2H, ArH), 7.42 (m, 2H, ArH),
7.33 (m, 1H, ArH), 7.25 (m, 1H, ArH), 7.04 (m, 1H, ArH), 6.99 (m, 1H, ArH), 6.75 (m, 1H, ArH).
(Figure S32). 13C NMR (CDCl3, 125 MHz, 25 °C)  145.35, 142.69, 141.32, 129.87, 128.79, 127.43,
127.25, 118.76, 114.94, 114.77. (Figure S33).
16
Figure S4. 1H NMR of 1 in DMSO-D6
Figure S5. 13C NMR of 1 in DMSO-D6
17
Figure S6. 1H NMR of 4-methoxybiphenyl in CDCl3
Figure S7. 13C NMR of 4-methoxybiphenyl in CDCl3
18
Figure S8. 1H NMR of 4-methylbiphenyl in CDCl3
Figure S9. 13C NMR of 4-methylbiphenyl in CDCl3
19
Figure S10. 1H NMR of 4-acetylbiphenyl in CDCl3
Figure S11. 13C NMR of 4-acetylbiphenyl in CDCl3
20
Figure S12. 1H NMR of 4-nitrobiphenyl
Figure S13. 13C NMR of 4-nitrobiphenyl in CDCl3
21
Figure S14. 1H NMR of 4-cyanobiphenyl in CDCl3
Figure S15. 13C NMR of 4-cyanobiphenyl in CDCl3
22
Figure S16. 1H NMR of 2-phenylpyridine in CDCl3
Figure S17. 13C NMR of 2-phenylpyridine in CDCl3
23
Figure S18. 1H NMR of 3-nitrobiphenyl in CDCl3
Figure S19. 13C NMR of 3-nitrobiphenyl in CDCl3
24
Figure S20. 1H NMR of aniline in CDCl3
Figure S21. 13C NMR of aniline in CDCl3
25
Figure S22. 1H NMR of 4-aminophenol in DMSO-D6
Figure S23. 13C NMR of 4-aminophenol in DMSO-D6
26
Figure S24. 1H NMR of 4-cyanoaniline in CDCl3
Figure S25. 13C NMR of 4-cyanoaniline in CDCl3
27
Figure S26. 1H NMR of 4-(pyridin-4-ylmethyl)aniline in CDCl3
Figure S27. 13C NMR of 4-(pyridin-4-ylmethyl)aniline in CDCl3
28
Figure S28. 1H NMR of 4-chloro-1,2-diaminobenzene in CDCl3
Figure S29. 13C NMR of 4-chloro-1,2-diaminobenzene in CDCl3
29
Figure S30. 1H NMR of 4-aminobiphenyl in CDCl3
Figure S31. 13C NMR of 4-aminobiphenyl in CDCl3
30
Figure S32. 1H NMR of 4-aminobiphenyl in CDCl3
Figure S33. 13C NMR of 3-aminobiphenyl in CDCl3
31
References.
1.
2.
3.
4.
5.
6.
D. D. Perrin and W. L. F. Armarego, Purification of Laboratory Chemicals. 3rd Ed, 1988.
J. Catalan, F. Fabero, M. Soledad Guijarro, R. M. Claramunt, M. D. Santa Maria, M. d. l. C.
Foces-Foces, F. Hernandez Cano, J. Elguero and R. Sastre, Journal of the American Chemical
Society, 1990, 112, 747-759.
G. M. Sheldrick, International Union of Crystallography, Crystallographic Symposia, 1991, 5,
145-157.
K. Matos and J. A. Soderquist, Journal of Organic Chemistry, 1998, 63, 461-470.
A. K. Shil and P. Das, Green Chem., 2013, 15, 3421-3428.
K. Layek, M. L. Kantam, M. Shirai, D. Nishio-Hamane, T. Sasaki and H. Maheswaran, Green
Chem., 2012, 14, 3164-3174.
32