A triazine-phosphite polymeric ligand bearing cage-like P,N-ligation sites: An efficient ligand in the nickel-catalyzed amination of aryl chlorides and phenols

Article abstract of DOI:10.1039/c6ra14367a

A novel P,N-ligand was introduced for efficient Ni-catalyzed amination of aryl chlorides. Reaction of cyanuric acid (1,3,5-triazine-2,4,6-triol) and trichlorophosphine (PCl₃) resulted in the production of a new porous material (TPPM) containing triazine rings with phosphite moieties in a sheet morphology. Cavities in the prepared compound create sites on the surface of the material with appropriate ligation character to coordinate with metals for catalytic purposes. The nickel-catalyzed amination of aryl chlorides and of phenols in their 2,4,6-triaryloxy-1,3,5-triazine (TAT) protected form were efficiently accomplished in the presence of this easily prepared and reusable P,N-ligand under mild reaction conditions. More importantly, TPPM was reusable for 5 iterations following this protocol without significantly decreasing in its activity.

Full text of DOI:10.1039/c6ra14367a

View Article Online
View Journal
RSC Advances
This article can be cited before page numbers have been issued, to do this please use: F. Panahi, F.
Roozbin, S. Rahimi, M. Moayyed, A. Valaei and N. Iranpoor, RSC Adv., 2016, DOI: 10.1039/C6RA14367A.
This is an Accepted Manuscript, which has been through the
Royal Society of Chemistry peer review process and has been
accepted for publication.
Accepted Manuscripts are published online shortly after
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. This Accepted Manuscript will be replaced by the edited,
formatted and paginated article as soon as this is available.
You can find more information about Accepted Manuscripts in the
Information for Authors.
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 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.
www.rsc.org/advances

Page 1 of 21
RSC Advances
View Article Online
DOI: 10.1039/C6RA14367A
A Triazine-Phosphite Polymeric Ligand Bearing Cagelike P,N-Ligation Sites:
As an Efficient ligand in Nickel-catalyzed Amination of Aryl Chlorides and
Phenols
Farhad Panahi,*[a],[b] Fatemeh Roozbin,[a] Sajjad Rahimi,[a] Mohammadesmaeil Moayyed,[a] Aria Valaei[a]
and Nasser Iranpoor*,[a]
[a] Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71454, Iran
Eꢀmail: iranpoor@chem.susc.ac.ir
[b] Department of Polymer Engineering and Color Technology, Amirkabir University of Technology,
Tehran, Iran
Eꢀmail: fpanahi@aut.ac.ir
Abstract
A novel P,Nꢀligand was introduced for efficient Niꢀcatalyzed amination of aryl chlorides. Reaction of
cyanuric acid (1,3,5ꢀtriazineꢀ2,4,6ꢀtriol) and trichlorophosphine (PCl3) resulted in the production of a new
porous material (TPPM) containing a triazine ring and phosphite moieties in sheet morphology. The
cavities of prepared compound create appropriate sites on the surface of the material with ligation
character to coordinate with metals for catalytic purposes. The nickelꢀcatalyzed amination of aryl
chlorides and also phenols as their 2,4,6ꢀtriaryloxyꢀ1,3,5ꢀtriazines (TATs) protected form were efficiently
accomplished in the presence of this easily prepared and reusable P,Nꢀligand under mild reaction
conditions. More importantly, TPPM was reusable for 5 times in this protocol without significant
decreasing in its activity.
Keywords: Polymeric Ligands, P,Nꢀligands, Nickelꢀcatalyzed amination, Aryl chlorides, Phenols
1

RSC Advances
Page 2 of 21
View Article Online
DOI: 10.1039/C6RA14367A
Introduction
There is often an emphasis on the development of ligands that influence efficiency and selectivity in
transition metalꢀcatalysis (TMC).[1] Heteroatomic bidentate ligands have received considerable attentions
in the recent years due to their widespread applications in TMC.[2] Phosphines are one of the most
important class of ligands in this field, showing high efficiency and applicability.[3] More importantly, the
heteroatomic bidentate P,Nꢀligands revealed their superiority in activity and selectivity between other
phosphorous containing ligands.[4] The importance of P,Nꢀligands is resulted from this fact that, as
soft/hard ligand able to coordinate reversibly to a metal center providing temporarily a vacant
coordination site, a feature very desirable for catalysis.[5] Therefore, the introduction of new, efficient,
easily prepared and applicable P,Nꢀligands is of much current interest and is the subject of extensive
research in this field.[6] The ideal form is the synthesis of an active P,Nꢀligand with simple workup and
purification process .
Supporting the ligands on a solid substrate is one of the subjects which allow the recycling of ligand
and simplifying workup process.[7] In this study we have focused on an easy approach, which relies on a
polymeric structure containing P,Nꢀligation sites. Organic polymers that contain ligated metals for
catalysis purposes, offer a variety of unique properties.[8] The strong coordination of metals to these
ligation centers resulted in the construction of catalytic positions for application in TMC.[8c,d] On the other
hand, the presence of catalytic sites on a flexible polymeric backbone can represent action of enzymes in
natural systems which can increase the interactions between the catalyst and substrates by folding of main
chains.[9] Furthermore, these structures caused increase of the local concentration of both substrates and
catalyst. Consequently, these functions not only lead to enhancements in reaction rates, but also provide
an easy scaffold for recycling.[10]
Herein, we disclosed the preparation of an easily prepared and reusable P,Nꢀligand from
commercially available and cheap starting materials in a single step process. Reaction of PCl3 with
2

Page 3 of 21
RSC Advances
View Article Online
DOI: 10.1039/C6RA14367A
cyanuric acid produces an organic polymer (triazineꢀphosphite polymeric material, TPPM) which is
introduced as a new P,Nꢀligand (Scheme 1).
Scheme 1. Synthesis of a triazineꢀphosphite polymeric material (TPPM) through the reaction of PCl3 with cyanuric
acid. Cyanuric acid as a white solid was reacted with PCl3 (a clear liquid) and forms a yellow solid which is a
triazineꢀphosphite compound. This material is unsolvable in solvents such as water, ethanol, ethyl acetate and nꢀ
hexane. The presence of P and N atoms in the structure of this material caused that it be usable as P,Nꢀligand in
TMC organic transformations.
In this study, TPPM was employed as ligand in metalꢀcatalyzed amination of aryl chlorides.[11] The
TMC amination of aryl halides is an important tool for the production of arylamines.[12] The expansion of
a simple metal catalyst system for the coupling of aryl electrophiles with NH3 is an important challenge in
the recent decade.[13] Most of these catalyst systems have done coupling reactions of aryl chlorides with
NH3 in low yields, especially with unactivated substrates.[14] The competition of solvent with NH3 was
observed in several cases and is a key limitation.[15] In some of the used methodologies, the produced
aniline product competes with ammonia in coupling reaction and the diaryl amine is the byproduct,
resulting in the decreasing of the yield and complication of purification process.[16] Furthermore, in most
cases, harsh reaction conditions are needed and very expensive and complicated catalyst system or ligand
was employed to accomplish this reaction.[17] As a result, description of a simple and efficient catalyst
system for the coupling of unactivated aryl chlorides with ammonia established the significance of our
new P,Nꢀligand to achieve high reactivity in TMC. Thus, the metalꢀcatalyzed reaction between aryl
3

RSC Advances
Page 4 of 21
View Article Online
DOI: 10.1039/C6RA14367A
chlorides and NH3 in the presence of this ligand was investigated. Furthermore, the amination of phenols
as their 2,4,6ꢀtriaryloxyꢀ1,3,5ꢀtriazines (TATs) protected form were evaluated in the presence of TPPM
ligand.
Results and Discussion
Synthesis and Characterization of TPPM
The TPPM ligand was simply synthesized using the reaction of PCl3 and cyanuric acid in the
presence of (nꢀPr)3N. Cyanuric acid immediately reacts with PCl3 and produces TPPM as a yellow solid
(Scheme 1). The reaction proceeded rapidly and afforded almost quantitative product yield. This
compound was characterized using 13CNMR, and FTꢀIR spectroscopies. There is one carbon atom at
13
149.8 ppm in CNMR spectrum of this compound which is attributed to the carbon of triazine ring (See
supporting information). The FTꢀIR of TPPM shows the appearance of PꢀO bond peak at 851 cmꢀ1. Also,
the peaks attributed to triazine ring with little shift appeared in the FTꢀIR spectrum (See supporting
information).[19]
The transmission electron microscopy (TEM) images of TPPM are shown in Figure 1. The TEM
images show the both porous and sheet nature of the TPPM material. The sheets and the holes of TPPM
are in the range of nanometers.
4

Page 5 of 21
RSC Advances
View Article Online
DOI: 10.1039/C6RA14367A
Figure 1. TEM images of TPPM from different positions and magnifications. The sheet morphology of
the synthesized TPPM is shown in TEM images a and b. TEM image of TPPM with high magnification
shows that the sheets are prose and cavities in the range of 10ꢀ40 nm are observable c-f. It seems that
TPPM strings to forms skims in sheet morphology with cavities in the range of nanometers. This cavities
are containing P,Nꢀligation sites which can be used as ligand in transitionꢀmetal catalysis.
The scanning electron microscopy (SEM) images of TPPM are shown in Figure 2. The SEM images
also prove the porous structure of TPPM and show cavities in the range of nanometer scale (Fig 2).
Figure 2. The SEM images of TPPM. The SEM images of TPPM with different magnification are
demonstrated the surface morphology of the material. The structure and surface of this material in terms
of nanoscale is shown in these images. Pores in the range of nm are observable on the surface of TPPM.
5

RSC Advances
Page 6 of 21
View Article Online
DOI: 10.1039/C6RA14367A
High porosity surface can be observed in the SEM images of material for all magnifications. At higher
magnification, the mesoporosity of material is becomes clear.
The sheet and porous structure of TPPM make it as a high surface area material which capable for
catalytic and isolation purposes. The TPPM was also analyzed using nitrogen adsorption–desorption
isotherms (Figure 3a). The adsorption isotherm is obtained by measuring the amount of nitrogen gas
adsorbed across the relative pressures at a constant temperature of 77K and conversely desorption
isotherms were achieved by measuring gas removed as pressure is reduced. The isotherm type is V
according to the Brunauer defind.[20] This type of isotherm shows small adsorbentꢀadsorbate interactions
potentials which associated with pores in the range of 1.5ꢀ100 nm. According to the Brunauer–Emmett–
Teller (BET) analysis, the specific surface area and pore volume of TPPM were calculated as 28.7 m2.gꢀ1
and 0.16 cm3.gꢀ1, respectively (Figure 3a & b).[21] The nano porous character of the TPPM was proved by
the Barrett–Joyner–Halenda (BJH) method (Figure 3c).[22] The BJH curve clearly displayed four peaks
with the pore size centered at about 4.61, 6.0, 8.0 and 24.0 nm, for four types of pores. These different
pores also confirm the nanoꢀporous nature of TPPM. Thus, this porous material with nanometer range
cavities and relatively good surface area is suitable for catalysis process.
Figure 3. The nitrogen adsorptionꢀdesorption isotherm of TPPM (3a). The type of isotherm shows small
adsorbentꢀadsorbate interactions potentials which associated with pores in the range of 1.5ꢀ100 nm. The
BET of TPPM (3b). The specific surface area and pore volume of TPPM were obtained using BET
6

Page 7 of 21
RSC Advances
View Article Online
DOI: 10.1039/C6RA14367A
analysis. The Vm, as,BET, C, total pore volume, and mean pore diameter for TPPM were 6.6 cmꢀ3.gꢀ1, 28.7
m2.gꢀ1, 24.9 nm, 0.16 cm3.gꢀ1, and 22.7 nm, respectively. The Barrett–Joyner–Halenda (BJH) analysis of
TPPM (3c). According to the BJHꢀplot of TPPM the Vp, rp,peak and ap were 0.17 cm3.gꢀ1, 4.61 nm, 40.7
m2.gꢀ1, respectively. The BJHꢀplot also confirms the nanoꢀporosity nature of TPPM.
The Xꢀray diffraction (XRD) pattern of TPPM material (Figure 4a) showed some strong peaks placed
at 2θ of 19.9, 22.6, 26.4, 29.9. These sharp peaks revealed highly crystalline nature of TPPM.[23] The
thermogravimetric analysis (TGA) of TPPM shows three main weight losses (Figure 4b). The first one is
accounted for adsorbed water in the structure of the material (1.92%). The second one occurred at 180–
290 °C (5.34%). The main decreasing in the weight percentage of the material at 290ꢀ420 °C is related to
decomposition of the compound structure. Thus, the TGA analysis indicates the high thermal stability of
material. Deferential scanning calorimetry (DSC) is a technique used to investigate the response of
polymers to heating. DSC can be used to study the melting of a crystalline polymer or the glass
transition.[24] The crystallization (Tc) and melting (Tm) peaks are only observed for polymers that can form
crystals. The crystallization temperature (Tc) of TPPM is occurs at ~210 °C. The DSC of TPPM also
shows an endothermic process which happens at ~390 °C. Purely amorphous polymers will only undergo
a glass transition. For semiꢀcrystalline polymers, the amorphous portion only undergoes the glass
transition while the crystalline regions only undergo melting. According the DSC analysis, it seems that
TPPM is a semiꢀcrystalline polymeric material.
The energyꢀdispersive Xꢀray (EDX) spectra of the TPPM material (Fig. 4d) show the elements P, N,
C and O with wt% of 14.62, 28.55, 24.61 and 30.93, respectively. Also the elemental analysis of the
TPPM material demonstrates the presence of C and N atoms with wt% of 23.84% and 29.56%,
respectively. Accordingly, it is possible to determine the experimental formula of this material
approximately, which estimated to be C3N3O3P0.75
.
7

RSC Advances
Page 8 of 21
View Article Online
DOI: 10.1039/C6RA14367A
Figure 4. The XRD pattern of TPPM (a); the existence of sharp peaks shows the crystalline nature of this
polymer. The TGA analysis of TPPM (b) shows three weights loses that the main loses (~76%) occur
around 290ꢀ400 °C which is in parallel to a sharp peak in DTG curve (b, dash line) at 390 °C. The DSC
curve of TPPM (c). The EDX analysis of TPPM (d) showed the elements of the compound including P, N,
C, and O with the W percentages of 14.62, 28.55, 24.61 and 30.93, respectively.
The experimental formula is in good agreement with a subunit that shown in Figure 5a. The
arrangements of triazine ring and phosphite groups generate chelation cavities which have role in the
porosity of this material. An optimized structure of a part of TPPM is shown in Figure 5b. These nanoꢀ
cavities with donor atoms of phosphorus and nitrogen can act as chelating ligand in the presence of a
metal (Figure 5c). The coordination of TPPM and a metal form a heterogeneous polymeric material
containing metal catalyst for application in organic transformations. The chemical structure of a Ni
complex of TPPM is shown in Scheme 5d.
8

Page 9 of 21
RSC Advances
View Article Online
DOI: 10.1039/C6RA14367A
Figure 5. Subunit structure of TPPM (a); if we consider the complete reaction of cyanuric acid with
trichlorophosphine it is possible to have subunits containing a phosphorous atom connected to three
hydroxyl group of three triazine rings. The optimize structure of a part of TPPM using Austin Model 1
(AM1) and representation of PN chelation cavities (b, c). A schematic representation the available sites of
TPPM for the chelation with metals such as Ni to generate heterogeneous catalyst systems for
applications in organic transformations (d).
Nickel-catalyzed amination of aryl chlorides using TPPM ligand
In order to evaluate the applicability of TPPM as ligand in TMC it was employed in metalꢀcatalyzed
amination of aryl chlorides. The metalꢀcatalyzed reaction between chlorobenzene and NH3 in the presence
9

RSC Advances
Page 10 of 21
View Article Online
DOI: 10.1039/C6RA14367A
of this ligand was investigated to obtain excellent yield of aniline. Different metals including Cu, Pd and
Ni (commonly used metal catalysts for this transformation) were used in order to determine which of
them is more efficient for the conversion of chlorobenzene to aniline in the presence of TPPM ligand
(Table 1).
Table 1. Optimization of metal in metalꢀcatalyzed amination of aryl chloride in the presence of TPPMa
Entry
Catalyst (mol%)
CuI (10)
Cu(OAc)2 (10)
Pd(OAc)2 (2)
NiCl2.5H2O (10)
Ni(PPh3)2(CO)2 (10)
Ni(COD) (10)
Ni(PPh3)4 (10)
Ni(PPh3)2(CO)2 (10)
Ni(PPh3)4 (10)
NH3
Yield 3a (%)b
75
70
20
none
90
92
(NH4)2SO4
(NH4)2SO4
(NH4)2SO4
(NH4)2SO4
(NH4)2SO4
(NH4)2SO4
(NH4)2SO4
(NH4)2SO4
(NH4)2SO4
1
2
3
4
5
6
7
8
9
75
35c
22c
a Reaction conditions: chlorobenzene (1.0 mmol), ammonium source (3.0 mmol), NaOtBu (1.5 mmol),
PEGꢀ200 (2.0 mL). b Yields are isolated product. cNo TPPM was used.
First, CuI was used as catalyst and about 75% of product was obtained (Table 1, entry 1).
Approximately same product was observed using Cu(OAc)2 as catalyst (Table 1, entry 2). In the presence
of Pd(OAc)2 as catalyst the reaction yield was decreased significantly (Table 1, entry 3). Also, by the use
of Ni(II) as catalyst no product was observed (Table 1, entry 4). However, maximum yield of product was
obtained using Ni(0) catalysts (Table 1, entries 5ꢀ7). Among tested Ni(0) catalyst Ni(COD)2 was the best
one (Table 1, entry 6). In the absence TPPM ligand the reaction yield for Ni(PPh3)2(CO)2 and Ni(PPh3)4
was significantly decreased, demonstrating the high efficiency of catalyst system for this transformation
(Table 1, entries 8 & 9). All of the reactions were checked in the presence of 50 mg of ligand, (NH4)2SO4
10

Page 11 of 21
RSC Advances
View Article Online
DOI: 10.1039/C6RA14367A
as NH3 source, NaOtBu as base and PEGꢀ200 as solvent. Then, amounts of Ni(0) and ligand was
optimized (Figure 6a&b) and it was observed that about 50 mg of TPPM ligand and 10 mol% of
Ni(COD)2 are necessary to obtain high yield of aniline using coupling of NH3 with chlorobenzene. In the
absence of TPPM ligand, the reaction yield was decrease significantly (20%), demonstrating the
important role of the ligand in this reaction. In the absence of metal catalyst no product was observed
(Figure 6a &b).
Figure 6. Optimized amount of Ni(COD)2 quantity (a). With increasing amount of Ni(0) from 3 mol% to
10 mol% the reaction yield was improved to 93% and after that no improvement was observed thus 10
mol% is the optimum amount of catalyst for this reaction. Optimization amount of TPPM ligand (b). In
the absence of ligand about 18% of product was observed and with increasing amount of ligand the
reaction yield was enhanced. About 50 mg of ligand is needed to obtain maximum yield of product.
11

RSC Advances
Page 12 of 21
View Article Online
DOI: 10.1039/C6RA14367A
Different ammonia source was used and (NH4)2SO4 was the best one (c). The best solvent for this reaction
was recognized PEGꢀ200, among tested solvents (d). Some bases including NaOtBu, Cs2CO3, NaOH,
K2CO3, and NaH was tested and maximum yield of product using NaOtBu was obtained (e). Amount of
base was optimized and 1.5 mmol of base is enough for this reaction.
Among tested ammonia sources, (NH4)2SO4 was recognized as the best one (Figure 6c). Other
solvents were also checked and no superiority was observed (Figure 6d). Also, in order to prove the only
solvent role of the PEGꢀ200, ethylene glycol was used; however the reaction yield was decreased to 35%.
This test clarify that the coordination capability of PEGꢀ200 with metal is not the key factor on the
superiority of this solvent related to other used. It should be mentioned that in ethanol and tertꢀbutanol the
reaction yields were 30 and 45%, respectively, confirming that alcoholic solvents are not suitable for this
methodology. Since, the type of base is important for this transformation some bases were checked and
best results were observed using NaOtBu (Figure 6e). Amount of base was optimized and 1.5 equivalent
of base was selected as optimum (Figure 6f). The optimized conditions for conversion of aryl chlorides to
anilines in the presence of TPPM ligand are shown in Scheme 2.
Scheme 2. Optimized conditions for amination of aryl chlorides using TPPM ligand. Reaction conditions:
aryl chloride (1.0 mmol), (NH4)2SO4 (2.0 mmol), NaOtBu (1.5 mmol), PEGꢀ200 (2.0 mL).
In another attempt the amination of phenols using their protected 2,4,6ꢀtriaryloxyꢀ1,3,5ꢀtriazine
(TAT)17f,25 compounds as an aryl CꢀO electrophile was also examined in order to extend the applicability
of the catalyst system in amination of phenolicꢀbased compounds (Scheme 3).
12

Page 13 of 21
RSC Advances
View Article Online
DOI: 10.1039/C6RA14367A
Scheme 3. Amination of 2,4,6ꢀtris(pꢀtolyloxy)ꢀ1,3,5ꢀtriazine (TPTT) under optimized conditions.
Reaction conditions: TPTT (0.35 mmol), (NH4)2SO4 (2.0 mmol), NaOtBu (1.5 mmol), PEGꢀ200 (2.0
mL).
The Niꢀcatalyzed crossꢀcoupling of NH3 with a range of aryl chlorides and TAT derivatives were
performed efficiently under our optimized conditions and the obtained results are shown in Scheme 4. As
established in Scheme 4, the substrates bearing different functional groups were all efficiently coupled
under these reaction conditions to provide the corresponding anilines in good to excellent isolated yields,
representing this methodology is a general and practical for the synthesis of diverse anilines.
Aryl electrophiles with functional groups such as alkyl (3b-d), carbonyl (3q), methoxy (3f-h), nitro
(3i,j), cyano (3k), acetyl (3l) and ether (3o&3r) reacted successfully. Some sterically hindered substrates
(3d&3f) succeeded in producing aniline. Heteroaryl substrates (3m&3n) can also be employed to prepare
their corresponding amine products. It should be mentioned that in all of the reaction the diaryl amine
byproduct was not observed. It seems that, the isolated sites of TPPM resulting from the triazine ring and
phosphite moiety can stabilize reactive intermediates on the surface toward the construction of product
and thus decrease byproduct formation.
13

RSC Advances
Page 14 of 21
View Article Online
DOI: 10.1039/C6RA14367A
Scheme 4. Products of Niꢀcatalyzed amination using TPPM as ligand. Reaction conditions: aryl chloride
(1.0 mmol) or TAT (0.35 mmol), (NH4)2SO4 (2.0 mmol), NaOtBu (1.5 mmol), PEGꢀ200 (2.0 mL). Yields
are isolated product. OTA= the leaving group of TAT.
We also employed the optimized conditions for the synthesis of various arylamines using other amine
substrates which are depicted in Scheme 5.26
14

Page 15 of 21
RSC Advances
View Article Online
DOI: 10.1039/C6RA14367A
R
N
X
Ni(COD)2 (10 mol%)
R
R
R
Ar
Ar
+
N
TPPM (50 mg)
NaOtBu, PEG-200
100-110 oC, 12h
H
4a-j
N
N
H3C
H3C
N
N
N
N
N
H3C
4b
4a
4c
CH3
4d
OMe
4e
X = Cl, 80%
X = Cl, 88%
X = OTA, 82%
X = Cl, 92%
X = OTA, 87%
X = Cl, 85%
X = Cl, 82%
N
N
CHO
N
N
N
H
N
11
N
MeO
4f
4i
4h
4g
OMe
X = Cl, 80%
X = OTA, 75%
X = Cl, 84%
X = OTA, 79%
X = Cl, 76%
X = Cl, 76%
X = Cl, 80%
Scheme 5. Products of Niꢀcatalyzed amination of different amines and aryl electrophiles using TPPM as
ligand. Reaction conditions: aryl chloride (1.0 mmol) or TAT (0.35 mmol), amine (1.0 mmol), NaOtBu
(1.5 mmol), PEGꢀ200 (2.0 mL). Yields are isolated product. OTA= the leaving group of TAT.
As shown in Scheme 5, the reactions of different amines (indole, pyrrole, carbazole, imidazole,
diphenylamine, and dodecyl amine) proceeded smoothly to furnish the corresponding arylamines with
moderate to good yields.
In order to show the recyclability of this catalytic system, first, Ni(COD)2 was complexed with TPPM
in PEGꢀ200 solvent at 100 °C and then applied in the coupling reaction between chlorobenzene and
(NH4)2SO4 and aniline was obtained in 90% isolated yield. The extracted catalyst from the reaction
mixture (after filtration, washing and drying) was applied for the next run and 88% of the product was
obtained. Overall, the catalyst system was reusable at least for 4 cycles (90, 88, 86, 84, 82%) with almost
15

RSC Advances
Page 16 of 21
View Article Online
DOI: 10.1039/C6RA14367A
consistent efficiency, demonstrating that Ni/TPPM acts a heterogeneous catalyst system in amination of
aryl chlorides. The ICP analysis from the catalyst after 4 cycle of reusability showed that less than 1
percent of Ni source was removed from the TPPM surface during the reaction progress. This result is in
good agreement with the efficiency of catalyst after each recovery. The TEM image showed the porous
network structure of the material after complexation no metal particle observed the image (Fig. 7a). The
SEM of the NiꢀTPPM complex shows that the morphology is not changed significantly during
complexation process of Ni and TPPM (Fig. 7b). The EDX analysis shows the presence of Ni in the
structure of NiꢀTPPM complex (Fig. 7c).
Figure 7. A TEM image (a) and SEM image (b) of NiꢀTPPM complex which show that the structure and
morphology of TPPM ligand remained unchanged after complexation with Ni(COD)2. The EDX analysis
of the NiꢀTPPM complex show the presence of Ni in the structure of the material.
This experiments and analysis revealed that the Ni moieties have good connection with ligation sites
of TPPM .
Conclusions
In conclusion, we have introduced a new P,Nꢀligand which can be used as a reusable P,Nꢀligand in
transitionꢀmetal catalyzed organic reactions. TPPM is a porous material in sheet morphology with cavities
in the range of nanometer scale which can act as an efficient ligand in organic reactions. These nanoꢀ
16

Page 17 of 21
RSC Advances
View Article Online
DOI: 10.1039/C6RA14367A
cavities create appropriate sites on the surface of this material with ligation character to coordinate with
metals for catalytic purposes. In this study, TPPM was used as ligand in metalꢀcatalyzed amination of aryl
chlorides and a combination of TPPM and Ni(COD)2 was found as an efficient catalyst system for the
conversion of aryl chlorides and protected phenols as their TAT substrates to anilines. Moreover, the
TPPM ligand provides great promise towards further useful applications in other transition metalꢀ
catalyzed organic transformations in future.
Acknowledgments
Financial support from the research councils of Shiraz University and a grant from the Iran National
Elite Foundation are gratefully acknowledged.
References
[1] a) S. Torker, R. K. M. Khan, A. H. Hoveyda, J. Am. Chem. Soc. 2014, 136, 3439ꢀ3455; b) G.
Sipos, E. E. Drinkel, R. Dorta, Chem. Soc. Rev. 2015, 44, 3834ꢀ3860; c) K. H. Shaughnessy, Chem. Rev.
2009, 109, 643ꢀ710; d) T. M. Shaikh, C.ꢀM. Weng, F.ꢀE. Hong, Coord. Chem. Rev. 2012, 256, 771ꢀ803;
e) J.ꢀH. Xie, Q.ꢀL. Zhou, Acc. Chem. Res. 2008, 41, 581ꢀ593.
[2] a) S. Toma, J. Csizmadiová, M. Mečiarová, R. Šebesta, Dalton Trans. 2014, 43, 16557ꢀ16579; b)
G. Helmchen, A. Pfaltz, Acc. Chem. Res. 2000, 33, 336ꢀ345.
[3] a) M. M. Pereira, M. J. F. Calvete, R. M. B. Carrilhoa, A. R. Abreu, Chem. Soc. Rev. 2013, 42,
6990ꢀ7027; b) H. FernándezꢀPérez, P. Etayo, A. Panossian, A. VidalꢀFerran, Chem. Rev. 2011, 111,
2119ꢀ2176.
[4] a) M. P. Carrolla, P. J. Guiry, Chem. Soc. Rev. 2014, 43, 819ꢀ833; b) G. Chelucci, G. Orrù, G. A.
Pinna, Tetrahedron 2003, 59, 9471; c) E. Fernández, P. J. Guiry, K. P. T. Connole, J. M. Brown, J. Org.
Chem. 2014, 79, 5391ꢀ5400.
17

RSC Advances
Page 18 of 21
View Article Online
DOI: 10.1039/C6RA14367A
[5] C. Holzhacker, M. J. Calhorda, A. Gil, M. D. Carvalho, L. P. Ferreira, B. Stöger, K. Mereiter, M.
Weil, D. Müller, P. Weinberger, E. Pittenauer, G. Allmaiere, K. Kirchner, Dalton Trans. 2014, 43, 11152ꢀ
11164.
[6] a) G. Farkas, Z. Császár, S. Balogh, I. Tóth, J. Bakos, Tetrahedron Lett. 2014, 55, 4120ꢀ4122; b)
K. Takeuchi, A. Minami, Y. Nakajima, F. Ozawa, Organometallics, 2014, 33, 5365ꢀ5370; c) S. K.
Gurung, S. Thapa, A. S. Vangala, R. Giri, Org. Lett. 2013, 15, 5378ꢀ5381; d) P. Nareddy, L. Mantilli1, L.
Guénée, C. Mazet, Angew. Chem. Int. Ed. 2012, 51, 3826; e) Y.ꢀH. Chang, Y. Nakajima, F. Ozawa,
Organometallics, 2013, 32, 2210ꢀ2215; f) R. J. Lundgren, B. D. Peters, P. G. Alsabeh, M. Stradiotto,
Angew. Chem. Int. Ed. 2010, 49, 4071ꢀ4074.
[7] a) Z. Xu, N. D. McNamara, G. T. Neumann, W. F. Schneider, J. C. Hicks, ChemCatChem 2013,
5, 1769ꢀ1771; b) L. Garcia, A. Roglans, R. Laurent, J.ꢀP. Majoral, A. PlaꢀQuintana; Caminade, A.ꢀM.
Chem. Commun. 2012, 48, 9248ꢀ9250.
[8] a) R. Shunmugam, G. N. Tew, Macromol. Rapid Commun. 2008, 29, 1355ꢀ1362; b) C. A.
Basinger, K. Sullivan, S. Siemer, S. Oehrle, K. A. Walters, J. Chem. 2015, 672654ꢀ11; c) X. Chena, H.
Zhua, T. Wanga, C. Lia, L. Yana, M. Jiang, J. Liu, X. Sund, Z. Jiang, Y. Ding, J. Mol. Catal. A: Chem.
2016, 414, 37ꢀ46; (d) Z. Yang, B. Yu, H. Zhang, Y. Zhao, Y. Chen, Z. Ma, G. Ji, X. Gao, B. Han, Z. Liu,
ACS Catal. 2016, 6, 1268ꢀ1273.
[9] a) M.J. Monteiro, Macromolecules 2010, 43, 1159ꢀ1168; b) R.J.R.W. Peters, I. Louzao, J.C.M.
van Hest, Chem. Sci. 2012, 3, 335; c) K. Renggli, P. Baumann, K. Langowska, O. Onaca, N. Bruns, W.
Meier, Adv. Funct. Mater. 2011, 21, 1241ꢀ1259.
[10] a) R. Chandrawati, M.P. van Koeverden, H. Lomas, F. Caruso, J. Phys. Chem. Lett. 2011, 2,
2639ꢀ2649; b) H. Gao, Macromol. Rapid Commun. 2012, 33, 722ꢀ734.
[11] S. Ge, R. A. Green, J. F. Hartwig, J. Am. Chem. Soc. 2014, 136, 1617ꢀ1627.
18

Page 19 of 21
RSC Advances
View Article Online
DOI: 10.1039/C6RA14367A
[12] A. Ricci. Modern Amination Methods. WileyꢀVCH, Weinheim, 2000.
[13] N. Xia, M. Taillefer, Angew. Chem. Int. Ed. 2009, 48, 337ꢀ339.
[14] Y. Aubin, C. Fischmeister, C. M. Thomas, J.ꢀL. Renaud, Chem. Soc. Rev. 2010, 39, 4130ꢀ4145.
[15] a) F. Lang, D. Zewge, I. N. Houpis, R. P. Volante, Tetrahedron Lett. 2001, 42, 3251; b) S.
Gaillard, M. K. Elmkaddem, C. Fischmeister, C. M. Thomas, J.ꢀL. Renaud, Tetrahedron Lett. 2008, 49,
3471ꢀ3474.
[16] a) Q. Shen, J. F. Hartwig, J. Am. Chem. Soc. 2006, 128, 10028ꢀ10029; b) G. D. Vo, J. F.
Hartwig, J. Am. Chem. Soc. 2009, 131, 11049ꢀ11061.
[17] a) J. P. Wolfe, S. L. Buchwald, J. Am. Chem. Soc. 1997, 119, 6054ꢀ6058; b) T. Shimasaki, M.
Tobisu, N. Chatani, Angew. Chem. Int. Ed. 2010, 49, 2929ꢀ2932; c) T. Mesganaw, A. L. Silberstein, S. D.
Ramgren, N. F. FineꢀNathel, X. Hong, P. Liu, N. K. Garg, Chem. Sci. 2011, 2, 1766ꢀ1771; d) S. D.
Ramgren, A. L. Silberstein, Y. Yang, N. K. Garg, Angew. Chem. Int. Ed. 2011, 50, 2171ꢀ2173; e) L. Hie,
S. D. Ramgren, T. Mesganaw, N. K. Garg, Org. Lett. 2012, 14, 4182; f) N. Iranpoor, F. Panahi, Adv.
Synth. Catal. 2014, 356, 3067ꢀ3073.
[18] O. Kühl. Phosphorusꢀ31NMR Spectroscopy. A Concise Introduction for the Synthetic Organic
and Organometallic Chemist. 2008 SpringerꢀVerlag Berlin Heidelberg.
[19] B. Chase (auth.), J. Mink, G. Keresztury, R. Kellner (eds.). Progress in Fourier Transform
Spectroscopy: Proceedings of the 10th International Conference. 1997, SpringerꢀVerlag.
[20] S. Brunauer, L. S. Deming, W. E. Deming, E. Teller, J. Am. Chem. Soc. 1940, 62, 1723ꢀ1732.
19

RSC Advances
Page 20 of 21
View Article Online
DOI: 10.1039/C6RA14367A
[21] a) L. D. Gelb, K. E. Gubbins, Langmuir, 1998, 14, 2097ꢀ2111; b) S. Storck, H. Bretinger, W. F.
Maier, Appl. Catal. A: Gen. 1998, 174, 137ꢀ146.
[22] E. P. Barrett, L.G. Joyner, P. P. Halenda, J. Am. Chem. Soc. 1951, 61, 373ꢀ380.
[23] L. R. Alexander. Xꢀray Diffraction Methods in Polymer Science. WileyꢀInterscience, 1969.
[24] N. Jing, A. Hammer. Thermal analysis of polymers, Part 5, DSC and TGA of elastomers
UserCom 35, 1ꢀ5.
[25] a) N. Iranpoor, F. Panahi, Org. Lett. 2015, 17, 214ꢀ217; b) N. Iranpoor, F. Panahi, F. Jamedi, J.
Organomet. Chem. 2015, 781, 6ꢀ10.
[26] A. Dumrath, C. Lbbe, H. Neumann, R. Jackstell, M. Beller, Chem. Eur. J. 2011, 17, 9599ꢀ9604.
20

Page 21 of 21
RSC Advances
View Article Online
DOI: 10.1039/C6RA14367A
Graphical Abstracts:
A reusable polymeric material containing P,Nꢀligation sites was prepared by a facile oneꢀstep route
for application in transitionꢀmetal catalysis as a reusable P,Nꢀligand. This material has cavities in the
range of nanometer. It was used as ligand in amination of various aryl chlorides and phenols efficiently to
synthesis corresponding aromatic amines in good to excellent yields.
21