Easily synthesizable benzothiazole based designers palladium complexes for catalysis of Suzuki coupling: Controlling effect of aryl substituent of ligand on role and composition of insitu generated binary nanomaterial (PdS or Pd16S7)

Article abstract of DOI:10.1016/j.catcom.2020.106242

The present report is based on straightforward synthesis of molecular palladium complexes of benzothiazole based bulky ligands. Catalytic potential of 1[Pd(L1)₂Cl₂] and 2[Pd(L2)₂Cl₂] has been screened for Suzuki coupling. Due to structural difference between 1 and 2 (anthracen-9-yl in 1, and pyren-1-yl in 2), they behave as designers pre-catalysts and show different catalytic behaviour and nature by dispensing the nanoparticles of different materials (PdS by 1 and Pd₁₆S₇ by 2). This is an unprecedented observation as the size of the aryl substituent controls the efficiency (efficiency: 1 > 2) through determining the composition and nature of insitu generated nanoparticles.

Full text of DOI:10.1016/j.catcom.2020.106242

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Easily synthesizable benzothiazole based designers palladium
complexes for catalysis of Suzuki coupling: Controlling the effect
of aryl substituent of ligand on role and composition of insitu
generated binary nanomaterial (PdS or Pd16S7)
Preeti Oswal, Aayushi Arora, Siddhant Singh, Gyandshwar
Kumar Rao, Sushil Kumar, Ajai K. Singh, Arun Kumar
PII:
S1566-7367(20)30318-6
DOI:
https://doi.org/10.1016/j.catcom.2020.106242
CATCOM 106242
Reference:
To appear in:
Catalysis Communications
Received date:
Revised date:
Accepted date:
5 September 2020
25 October 2020
11 November 2020
Please cite this article as: P. Oswal, A. Arora, S. Singh, et al., Easily synthesizable
benzothiazole based designers palladium complexes for catalysis of Suzuki coupling:
Controlling the effect of aryl substituent of ligand on role and composition of insitu
generated binary nanomaterial (PdS or Pd16S7), Catalysis Communications (2020),
https://doi.org/10.1016/j.catcom.2020.106242
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Easily synthesizable benzothiazole based designers palladium complexes for
catalysis of Suzuki coupling: Controlling the effect of aryl substituent of ligand
on role and composition of insitu generated binary nanomaterial (PdS or Pd16S7)
Preeti Oswal,a Aayushi Arora,a Siddhant Singh,a Gyandshwar Kumar Rao,b Sushil Kumar,a
Ajai K. Singh c and Arun Kumar*a
aDepartment of Chemistry, School of Physical Sciences, Doon University, Dehradun, India.
bDepartment of Chemistry, Biochemistry and Forensic Science, Amity School of Applied Sciences, Amity
University Haryana, Gurgaon, Haryana, 122413, India.
cDepartment Of Chemistry, Indian Institute of Technology, Delhi, New Delhi, India.
Corresponding author: Arun Kumar, e-mail:arunkaushik@gmail.com, akumar.ch@doonuniversity.ac.in
Abstract
The present report is based on straightforward synthesis of molecular palladium complexes of
benzothiazole based bulky ligands. Catalytic potential of 1[Pd(L1)2Cl2] and 2[Pd(L2)2Cl2] has
been screened for Suzuki coupling . Due to structural difference between 1 and 2 (anthracen-9-yl
in 1, and pyren-1-yl in 2), they behaves as designers pre-catalysts and show different catalytic
behaviour and nature by dispensing the nanoparticles of different materials (PdS in 1 and Pd16S7
in 2). This is an unprecedented observation as the size of the aryl substituent controls the
efficiency (efficiency: 1 > 2) through determining the composition and nature of insitu generated
nanoparticles.
Keywords: Benzothiazole, Palladium, Nanoparticles, Suzuki coupling, Palladium sulfide
1. Introduction
In transition-metal catalysis, the role of ligands is very crucial [1−9]. The ligands show
influence on (i) the operational properties of the catalytic reaction (the compatibility with air

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and/or moisture, the reaction temperature, pressure, etc), (ii) reactivity of a metal catalyst, (iii)
selectivity (i.e., enantioselectivity, diastereoselectivity, regioselectivity, and chemoselectivity) of
a chemical reaction, (iv) stabilization of insitu generated active and real catalytic species [1-9].
Therefore, these are considered to be chemists’ “hands” for influencing the bond-making and -
breaking processes, and improving known catalytic reactions. Effect of ligands architecture on
catalytic process has been studied experimentally [1-9] as well as theoretically [10-12]. An
appropriate ligand for a particular set of reactants or a particular reaction can be easily accessed
by fine tuning its electronic and steric properties through modifications. Such modifications may
involve variation in donor sites such as S/Se/Te/P/O/N and/or removal or incorporation of
substituents of different sizes in the ligand. Many research groups have reported the effect of
presence of bulky substituents in ligand on the catalysis. In context of phosphine ligands,
Buchwald and other researchers have rationalized the influence of bulky substituents in terms of
extent of stabilization of intermediate species [formed during oxidative addition step due to (i)
cleavage of bond between organic R group and the heteroatom X, and (ii) simultaneous
formation of a new bond] by bulky ligands [9,10]. In addition, the bulkiness of ligand also
promotes reductive elimination step for release of coupling product [9,10]. This strategy of
modifying the ligand architecture and screening the effects on catalysis can be successfully
applied only if modifications can be carried out easily and readily. Hence, ease and simplicity of
methodology for tailoring ligand’s architecture has a high significance in making a particular
class of ligands convenient to use. Probably it is also among the major reasons why Schiff bases,
pincer ligands, organochalcogen ligands, heterocyclic compounds including triazoles, pyridine
etc have emerged as large and distinguished families of ligands for developing transition metal
catalytic systems for various chemical transformations [13-16].

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Benzothiazole and its derivatives are very important scaffolds under the class of heterocyclic
organic molecules. During last four decades, they have been explored extensively upto a great
extent in the syntheses of molecules of medicinal use [17−19]. Despite the availability of a C=N-
and a -S- donor group in its framework and first report on application of its palladium complex
in catalysis in year 2000 [20], work done during last two decades on use of the benzothiazole or
its derivatives in developing transition metal catalytic systems is negligible in comparison to that
on Schiff bases, pincer ligands, organochalcogen ligands and phosphines. For this purpose, the
exploration of these compounds is much lesser than that of other heterocyclic compounds e.g.
pyridine and triazoles. Only a few palladium complexes of this ligand scaffold (benzothiazole or
its derivatives) have been synthesized and used in catalysis of coupling reactions, CO2 reduction,
hydrogenation [20-27]. It is probably because, unlike aforementioned popular and commonly
used ligands, their derivatization and functionalization has not been very facile and easy due to
which scope of modulation in ligand’s steric and electronic properties remains limited. Therefore
syntheses of benzothiazoles derivatives by using easy, convenient, efficient methods always
attract the attention of inorganic chemists. Though a variety of methodologies are reported [28]
for syntheses of its derivatives, the most attractive and least explored in the synthesis of
benzothiazole based ligands is a reaction between aminothiophenol and a carbonyl compound, as
simple as a Schiff base reaction [28].
Suzuki Miyaura C-C coupling reaction is one of the most useful tool for formation of C-C
bond during syntheses and large scale preparation of pharmaceuticals, agrochemicals and fine
chemicals [29−32]. Though, a large number of catalysts have been developed [29,30], there is
still a focus of various research groups on the development of more efficient, stable and easily

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synthesizable catalysts. Moreover, the palladium complexes of benzothiazole based ligands have
been rarely explored for this reaction [21,24,25,26]
Taking into account the aforementioned status of exploration of benzothiazole based ligands
in development of transition metal catalytic systems and related reasons, it was thought to be
worthwhile (i) to begin the use of a green, facile, catalyst free and room temperature reaction
protocol for synthesizing ligands with bulky substituents at C-2 of benzothiazole core, (ii) to
synthesize their designers palladium complexes, and to screen their catalytic potential in Suzuki-
Miyaura coupling with gaining insights into the role of bulky substituents in catalytic process.
In the present study, we are reporting easily synthesizable designers palladium(II) complexes
1 and 2, designed using L1 [33] and L2 [34], and their applications in the catalysis of Suzuki
coupling of a variety of bromo and chloroarenes. L1 and L2 have been prepared using one-pot
and green method of syntheses. Mechanistic insights have also been gained into process of
catalysis and high efficiency have been rationalized in terms of activity of insitu generated
nanoparticles, the composition (i.e. PdS or Pd16S7) of which is controlled by the size or nature of
bulky aryl group present on the ligands L1 and L2.
2. Results and discussion
2.1. Syntheses and structures
Bulky ligands L1 and L2 have been accessed in very good yields (~80%) in short reaction
time of 2 hours at room temperature using a methodology (involving a reaction between 2-
aminothiophenol and an aromatic aldehyde) which is highly attractive, least explored, facile,
1
green, one pot and catalyst-free. The L1 and L2 have been characterized by matching their H
NMR spectral features with reported data [33, 34]. Pd(II) complexes 1 and 2 have been

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synthesized by reaction of Na2PdCl4 with L1/L2 in an extremely short reaction time of five
minutes. Both 1 and 2 are stable under ambient conditions and may be stored for several months
1
without noticeable decomposition. The 1 and 2 were characterized by H, 13C{1H} NMR
spectroscopy and mass spectrometry (Supplementary Material: Figs. S1−S9). These
spectroscopic and spectrometric data are consistent with the molecular structures shown in
Scheme 1.
Na2PdCl4
Acetone+ Water,
N
S
RT, 5 min
Cl
L1
S
N
Pd
N
S
Complex 1
Cl
EtOH, RT,
2h
9-Anthraldehyde
NH2
SH
R
PdS
R
X
+
1-Pyrenecarbox-
aldehyde
Ar
EtOH, RT
2h
ArB(OH)2
Pd16S7
N
S
S
N
Cl
Na2PdCl4
Pd
Cl
N
Acetone
+ Water,
RT, 5 min
S
Complex 2
L2
Scheme 1. Syntheses of ligands (L1 and L2), Pd(II) complexes (1 and 2) and application of 1
and 2 in catalysis of Suzuki coupling through insitu generated nanoparticles of PdS and Pd16S7

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The molecular structures of L1 (Fig. 1) and 1 (Fig. 1) were also authenticated by single
crystal X-ray diffraction studies. The crystal data and details of structure refinement for L1 and 1
are given in Supplementary Material. X-ray diffraction studies revealed that in the complexes,
the ligand coordinates (Fig. 1) with the Pd(II) centre through nitrogen in monodentate mode in
such a manner that bulky aryl substituents are oriented in opposite directions. In palladium
complex 1, the geometry around the Pd is nearly square planer. The Pd−N bond lengths are
2.023(10) Å and Pd−Cl bond lengths are found to be 2.319(2).
Fig. 1. Trans disposition of ligand (L1) molecules in square planar geometry of palladium ion in
complex 1, obtained by the reaction of L1 and Na2PdCl4

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2.2. Catalysis of Suzuki coupling
After optimizing (Table S1 in Supplementary Material) the reaction conditions, the catalytic
potentials of 1 and 2 for Suzuki-Miyaura coupling reactions were screened at 90 ℃ using K2CO3
as the base for 8 hours for ArBr, and 12 hours for ArCl. It has been observed that generally the
efficiency of complex 1 (in which aryl substituent at C-2 is antrcen-9-yl) is higher than that of
complex 2 (in which aryl substituent i.e. pyren-1-yl group is more bulky). Among bromoarenes,
maximum conversion (≥99%) was achieved (Table 1: Entry nos. 1-4) in case of 4-
bromobenzophenone, 4-bromobenzaldehyde, 2-bromothiophene and 4-bromobenzonitrile when
complex 1 was used as a catalyst. However, conversions of these substrates were in between 80-
95% when complex 2 was used as a catalyst. Minimum conversion (< 30%) was observed (Table
1: Entry no. 6) for 4-bromophenol in presence of either of the two catalysts. 1-Bromo-4-
nitrobenzene was the only substrate (Table 1: Entry no. 5) for which complex 2 was found to be
slightly more efficient than complex 1. In case of aryl bromides with electron donating
substituents (such as 4-bromotoulene and 4-bromoanisole), relatively lower yields of coupled
products have been obtained (Table 1: Entry no. 16 and 18).

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Table 1. Results of Suzuki coupling reactions of aryl halides with phenyl boronic acid, 4-
methoxyphenyl boronic acid and 4-formylphenyl boronic acid.
Ar−X + Ar'B(OH)2
→
Ar−Ar'
Aryl halide
(Ar-X)
% Conversion of the
aryl halide into product
(value of TON)
S.
No.
Cross-coupled product
Complex 1 Complex 2
O
4-Bromobenzophenone
99% (9900) 90% (9000)
1.
4-Bromobenzonitrile
4-Bromobenzaldehyde
2-Bromothiophene
99% (9900) 90% (9000)
99% (9900) 95% (9500)
99% (9900) 80% (8000)
CN
2.
3.
4.
CHO
S
1-Bromo-4-Nitrobenzene
4-Bromophenol
NO2
OH
71% (7100) 78% (7800)
29% (2900) 25% (2500)
5.
6.
Chlorobenzenea
99% (9900) 78% (7800)
95% (9500) 88% (8800)
92% (9200) 85% (8500)
7.
8.
4-Chloroanilinea
NH2
NO2
1-Chloro-4-Nitrobenzenea
9.
10.
4-Chloroacetophenonea
4-Chlorobenzophenonea
87% (8700) 80% (8000)
86% (8600) 75% (7500)
COCH3
O
11.

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4-Chlorobenzonitrilea
4-Chlorobenzaldehydea
2-Chlorobenzonitrilea
76% (7600) 66% (6600)
75% (7500) 71% (7100)
67% (6700) 63% (6300)
CN
12.
13.
14.
CHO
CN
4-Chlorotoulenea
4-Bromotoulene
53% (5300) 50% (5000)
72% (7200) 66% (6600)
CH3
CH3
15.
16.
Bromobenzene
4-Bromoanisole
4-Chloroanisolea
Chlorobenzenea,b
83% (8300) 75% (7500)
60% (6000) 48% (4800)
30% (3000) 26% (2600)
91% (9100) 89% (8900)
67% (6700) 61% (6100)
10% (1000) 12% (1200)
30% (3000) 30% (3000)
17.
18.
19.
20.
21.
22.
23.
24.
OMe
OMe
MeO
MeO
MeO
MeO
MeO
1-Chloro-4-Nitro
benzenea,b
NO2
4-Chlorobenzaldehydea,b
4-Chlorotoulenea,b
CHO
CH3
4-Chloroanisolea,b
6% (600)
8% (800)
OMe
Chlorobenzenea,c
82% (8200) 70% (7000)
95% (9500) 84% (8400)
25.
26.
OHC
1-Chloro-4-Nitro
benzenea,c
NO2
OHC

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4-Chlorobenzaldehydea,c
4-Chlorotoulenea,c
78% (7800) 71% (7100)
75% (7500) 58% (5800)
27.
28.
29.
CHO
CH3
OHC
OHC
OHC
4-Chloroanisolea,c
25% (2500) 32% (3200)
OCH3
b
Reaction conditions: Aryl halide (1 mmol), phenyl boronic acid (1.5 mmol), 4-methoxyphenyl
c
boronic acid (1.5 mmol), 4-formylphenyl boronic acid (1.5 mmol), [Catalyst]Complex 1/2 (0.01
mol%), K2CO3 (2 mmol), DMF+water (5 mL), reaction time 8 h, temperature of bath, 90 ℃,
areaction time 12 h.
For Suzuki coupling reactions, aryl chlorides are the most preferred substrates due to their
low cost, wide availability and easy accessibility. However, due to high C−Cl bond strength,
their reactivity is minimum and only highly active catalyst are able to convert them into coupled
products. Both the complexes have also shown good catalytic potential for coupling reactions of
such
substrates.
Chlorobenzene,
4-chloroaniline,
1-chloro-4-nitrobenzene,
4-
chloroacetophenone, 4-chlorobenzaldehyde, 4-chlorobenzonitrile and 4-chlorobenzophenone
were converted (Table 1: Entry nos. 7-13) successfully to desired products at same catalyst
loading (0.01 mol%) as used in case of bromoarenes in 12 h at 90 °C. However, chloroarenes
with electron donating substituents on benzene ring (Table 1: Entry nos. 15 and 19) gave very
low yields.
To have a better understanding on the catalyst activity, other aryl boronic acids
possessing electron donating and withdrawing group on benzene ring have also been
investigated. When 4-methoxyphenyl boronic acid (a phenyl boronic acid with electron donating
group) is used, both the complexes show suppressed activities (Table 1: Entry nos. 20−24) in
comparison to those shown for PhB(OH)2. However, in case of 4-formylphenyl boronic acid (a

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boronic acid with electron withdrawing group on benzene ring), marginally higher catalytic
efficiencies (Table1: Entry nos. 25−29 ) are shown by both the complexes.
2.3. Insitu generation of nanoparticles of PdS and Pd16S7 and their role in catalysis
During the course of catalysis, formation of black particles was observed. Therefore, it is
quite likely that palladium complexes 1 and 2 are pre-catalysts and behave as the dispensers of
true catalytic species during the course of catalytic reaction. So, with a purpose to get insights
into the role of such particles, a coupling reaction between 1-bromo-4-nitrobenzene and
phenylboronic acid, catalyzed with complex 1 and 2 has been analyzed thoroughly and
separately. The black particles, formed insitu, were isolated and characterized by P-XRD, SEM-
EDX, HR-TEM and XPS. Powder X-ray diffraction patterns (Supplementary Material: Figs. S12
and S13) of these particles revealed that these are belonging to binary phases (PdS in case of
catalysis with complex 1 and Pd16S7 in case of complex 2) when matched with standard phases
JCPDS # 25-1234 (for PdS) [35] and JCPDS # 43-0806 (for Pd16S7). The SEM-EDX studies
(details in Supplementary Material) also support the presence of both the elements (i.e. Pd and S)
in the nanoparticles generated from 1 and 2. XPS studies of the nanoparticles also corroborate
the presence of binary phases (PdS and Pd16S7) (Fig. 2 and 3). In case of PdS nanoparticles,
palladium is present in +2 oxidation state. However, in case of NPs of Pd16S7, presence of both

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Fig. 2. XPS Spectra of PdS nanoparticles obtained from complex 1
Fig. 3. XPS Spectra of Pd16S7 nanoparticles obtained from complex 2
Pd(0) and Pd(II) oxidation states have been observed. Presence of peaks, corresponding to
sulfide ion, has also been observed in both the phases (Supplementary Material S5). On the basis
of similarity in the structures of the complex and reaction conditions, it can be inferred that

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formation of different materials (i.e. compositions of particles) is controlled mainly by the size of
the aryl group (anthracen-9-yl in case of complex 1 and pyren-1-yl in case of complex2) linked
at C-2 of the benzothiazole framework.
Fig 4. TEM images of nanoparticles generated in situ during catalysis
The HRTEM images (Fig. 4) revealed that the particles generated from the complexes are
nanosized. Nanoparticles generated by complex 1 are ~10−12 nm in size, spherical in shape and
uniformly dispersed. However, in case of isolated nanoparticles by complex 2, there is an
aggregation due to which their dispersion is not good. Hence, the difference in the catalytic
activities of 1 and 2 may be attributed to two factors: (i) insitu generated nanoparticles have
different compositions (i.e. PdS in case of complex 1 and Pd16S7 in case of complex 2), (ii) in-
situ generated PdS nanoparticles with 1 are well dispersed and small in size (Fig. 4) as compared
to Pd16S7 nanoparticles generated with 2 in which there is an aggregation of nanoparticles
(clearly visible in HRTEM image).
In order to ascertain the role of in situ generated nanoparticles of Pd-S materials (PdS and
Pd16S7) in catalysis and their catalytic properties, they were isolated and obtained outside the
reaction mixture. Their catalytic potential was tested separately for Suzuki coupling reactions

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(Table 2) of ArBr as well as ArCl. Noticeably, a higher catalyst loading (~3.5-4.1 mol%) was
required to achieve comparable conversions. It corroborates that the eventual advantages of
using preformed molecular complexes 1 and 2 in catalysis is the formation of products in higher
or comparable yields at very low concentration (0.01 mol%) of catalyst. The potential, shown by
nanoparticles, in achieving good but different yields (Table 2) of cross-coupled products is also
the basis for inferring that catalysts 1 and 2 acts as dispensers of nanoparticles PdS and Pd16S7
and their activity is dependent upto a significant extent on the activity of the NPs.
Table 2. Results of catalysis of Suzuki coupling reactions (between aryl halides and
phenylboronic acid) catalyzed by isolated NPs of PdS and Pd16S7
Ar−X + PhB(OH)2
Entry
→
Ar−Ph
Cross-coupled product
Aryl halide
(Ar-X)
% Conversion of aryl halide
NPs of PdS
NPs of Pd16S7
1.
1-Bromo-4-
nitrobenzene
89%
86%
O2N
2.
4-Bromobenzoic
acid
HOOC
O2N
92%
68%
3.
4.
1-Chloro-4-
nitrobenzenea
Chlorobenzenea
29%
78%
52%
74%
5.
6.
7.
4-Chlorotoulenea
70%
60%
35%
66%
52%
28%
H3C
NC
O
4-
Chlorobenzonitrilea
4-Chloroanisolea
Reaction conditions: aryl halide (1 mmol), phenyl boronic acid (1.5 mmol), catalyst 5 mg,
a
K2CO3 (2 mmol), DMF+water (5 mL), reaction time 8 h, temperature of bath 90 °C, reaction
time 12 h.

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Mercury poisoning test and triphenyl phosphine tests were carried out in order to establish
whether the nature of catalysis is homogeneous or heterogeneous. Coupling reaction between 1-
bromo-4-nitrobenzene and phenyl boronic acid in presence of poison (i.e. mercury) gave 17%
and 23% conversion of substrate with 1 and 2 as catalyst respectively. Similarly, a reaction
between 4-bromobenzaldehyde and PhB(OH)2 in presence of PPh3 was also suppressed to a great
extent and 42% and 29% conversion was obtained with 1 and 2 respectively. These results
suggest that insitu generated palladium nanoparticles (PdS, Pd16S7) contribute to catalysis of
Suzuki coupling upto a great extent. However, possibility of catalysis by some homogeneous low
valent palladium species, stabilized by bulky substituents of ligands of both the complexes, can
also not be ruled out as the reaction proceeds upto some extent even in the presence of poisoning
agents such as PPh3 and Hg. Thus, it appears that overall the catalysis in case of 1 and 2 is
cocktail of homogeneous as well as heterogeneous mode [8].
3. CONCLUSION
In conclusion, the methodology used for synthesis of L1 and L2 opens up a field with a
wider scope for the modular syntheses of a library of numerous ligands by using appropriate
derivatives of either aminothiphenol or carbonyl compounds as reactants. Pd(II) complexes 1 and
2, which are moisture- and air−insensitive and have potential to catalyze the Suzuki coupling of
both ArCl and ArBr, behaves as designers catalysts and controls their activity upto a great extent
through the size of aryl substituent of the ligand. This aryl substituent (anthracen-9-yl in complex
1 and pyren-1-yl in 2), in turn, determines the nature and composition of nanosized material (i.e.
PdS and Pd16S7) dispensed insitu by the complexes during reaction. Interestingly, unlike the
earlier reports, it is the first time when insitu formation of nanoparticles of palladium
chalcogenides (PdS or Pd16S7) has been reported from the complexes which does not contain any

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direct linkage (i.e. bond) between metal and chalcogen. These results imply that catalytic nature,
behaviour and efficiency of the palladium complexes can be modulated simply by minor
variations in the substituents at C−2 of benzothiazole based ligands.
Declaration of Competing Interest
There are no conflicts to declare.
Acknowledgements
P.O. acknowledge DST for INSPIRE Fellowship [DST/INSPIRE Fellowship/2017/IF170491].
A.K. and A.A. acknowledges Science and Engineering Research Board (SERB), New Delhi,
India for fellowship through project [ECR/2016/001549]. S.K. thanks DST for INSPIRE Faculty
Award [DST/INSPIRE/04/2015/002971].
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Declaration of interests: NONE
Easily synthesizable benzothiazole based designers palladium complexes for
catalysis of Suzuki coupling: Controlling the effect of aryl substituent of ligand
on role and composition of insitu generated binary nanomaterial (PdS or Pd16S7)
Preeti Oswal,a Aayushi Arora,a Siddhant Singh,a Gyandshwar Kumar Rao,b Sushil Kumar,a
Ajai K. Singh c and Arun Kumar*a
aDepartment of Chemistry, School of Physical Sciences, Doon University, Dehradun, India.
bDepartment of Chemistry, Biochemistry and Forensic Science, Amity School of Applied Sciences, Amity
University Haryana, Gurgaon, Haryana, 122413, India.
cDepartment Of Chemistry, Indian Institute of Technology, Delhi, New Delhi, India.
Corresponding author: Arun Kumar, e-mail:arunkaushik@gmail.com, akumar.ch@doonuniversity.ac.in
Declaration of interests: NONE
☐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.

Journal Pre-proof
Easily synthesizable benzothiazole based designers palladium complexes for
catalysis of Suzuki coupling: controlling effect of aryl substituent of ligand on
role and composition of insitu generated binary nanomaterial (PdS or Pd16S7)
Preeti Oswal, a Aayushi Arora, a Siddhant Singh, a Gyandshwar Kumar Rao, b Sushil Kumar,a
Ajai K. Singhc and Arun Kumar*a
aDepartment of Chemistry, School of Physical Sciences, Doon University, Dehradun, India
bDepartment of Chemistry, Biochemistry and Forensic Science, Amity School of Applied Sciences, Amity
University Haryana, Gurgaon, Haryana, 122413, India.
cDepartment Of Chemistry, Indian Institute of Technology, Delhi, New Delhi, India
Corresponding author: Arun Kumar, e-mail:arunkaushik@gmail.com, akumar.ch@doonuniversity.ac.in

Journal Pre-proof
Easily synthesizable benzothiazole based designers palladium complexes for
catalysis of Suzuki coupling: controlling effect of aryl substituent of ligand on
role and composition of insitu generated binary nanomaterial (PdS or Pd16S7)
Preeti Oswal,a Aayushi Arora,a Siddhant Singh,aGyandshwar Kumar Rao,b Sushil Kumar,a
Ajai K. Singhc and Arun Kumar*a
aDepartment of Chemistry, School of Physical Sciences, Doon University, Dehradun, India.
bDepartment of Chemistry, Biochemistry and Forensic Science, Amity School of Applied Sciences,
Amity University Haryana, Gurgaon, Haryana, 122413, India.
cDepartment Of Chemistry, Indian Institute of Technology, Delhi, New Delhi, India.
Corresponding author: Arun Kumar, e-mail:arunkaushik@gmail.com,
akumar.ch@doonuniversity.ac.in
 Straightforward synthesis of stable Pd(II)-complexes with bulky aryl groups.
 Designers catalysts with high activity for Suzuki coupling of ArBr and ArCl.
 Role of composition and nature of insitu generated binary materials in catalysis.
 Aryl group of ligand controls the composition (PdS or Pd16S7) of nanomaterials.
 Ligand synthesis protocol is green, one pot, room temperature and catalyst-free.