view article online rsc advancesiiti.ac.in/people/~xray/rsc adv.pdfcatalyst such as au, pd, pt, rh,...

www.rsc.org/advances

RSC Advances

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.

View Article OnlineView Journal

This article can be cited before page numbers have been issued, to do this please use: A. Mohammad, V.

MISHRA, P. Chandra and M. M. Shaikh, RSC Adv., 2016, DOI: 10.1039/C6RA12920J.

http://dx.doi.org/10.1039/C6RA12920J

http://pubs.rsc.org/en/journals/journal/RA

http://crossmark.crossref.org/dialog/?doi=10.1039/C6RA12920J&domain=pdf&date_stamp=2016-05-27

RSC Advances

ARTICLE

This journal is © The Royal Society of Chemistry 20xx J. Name., 2013, 00, 1-3 | 1

Please do not adjust margins


a. Akbar Mohammad, Veenu Mishra, Prakash Chandra and Shaikh M. Mobin

Discipline of Chemistry, Indian Institute of Technology Indore, Simrol, Indore 452020,

M.P.,India

E-mail: [email protected]

b. Shaikh M. Mobin

Centre for Material Science and Engineering,

Indian Institute of Technology Indore, Simrol, Indore 452020, M.P., India.

E-mail:[email protected]

Electronic Supplementary Information (ESI) available: [details of any supplementary information available should be included here].

Received 00th January 20xx,

Accepted 00th January 20xx

DOI: 10.1039/x0xx00000x

www.rsc.org/

Reduction of selective polyaromatic nitrotriptycene via

azoxytriptycene intermediate under ambient conditions using

cobalt/cobalt oxide nanocomposite (CoNC)

Akbar Mohammad,a Veenu Mishra,a Prakash Chandraa and Shaikh M. Mobin*a,b

Cobalt-based nanocomposite (CoNC) has been prepared from recently reported single source molecular precursor (SSMP)

[CoII(hep-H)(H2O)4]SO4 (A) (hep-H= 2-(2-hydroxylethyl) pyridine). The resulting nanocomposite material was characterized

by using various physicochemical techniques such as XRD, SEM, EDAX, TEM and XPS spectroscopy. X-ray diffraction pattern

shows weakly crystalline nature of the catalyst. This was also confirmed by SAED pattern obtained from HR-TEM. XPS

analysis reveals the formation of metallic cobalt and cobalt oxide (CoO) nanocomposite.CoNC was employed for the facile

catalytic hydrogenation of 2-nitrotriptycene (M1) and 2,6,14-trinitrotriptycene (M2) as model substrates under

atmospheric reaction conditions, which otherwise takes place either by Raney-Ni or Pd/C or SnCl2/HCl catalyst under

drastic conditions. The mechanistic pathway reveals that the reduction of M1 proceeds via the intermediacy of azoxy

triptycene (III) and N-hydroxylamine triptycene (IV).

Introduction

Catalysis has revolutionized today’s chemical

manufacturing. One such manufacturing process is reduction

of organic molecules by catalytic hydrogenation. Last few

decades witness an enormous progress in the field of catalytic

hydrogenation of aliphatic/aromatic nitro compounds. In this

process the focused was on improving the conversion yields by

varying the i) reaction conditions, ii) catalyst from metal to

non-metal, and iii) solvents.1 The catalytic transformation of R-

NO2 to R-NH2 undergoes via the formation of versatile

intermediates, aryl hydroxylamine, azoxy and azo compounds.2

These products and intermediates are potentially used in

biologically active natural products, dyes, pigments, polymers,

pharmaceuticals, and agro-chemicals.3 In general, the catalytic

hydrogenation involved the use of noble or expensive metal

catalyst such as Au, Pd, Pt, Rh, Ru or Raney Ni.4 Generally, the

use of Raney Ni in industrial process believes to be effective

due to the fact that no side product except water is formed.

However, the key disadvantages of Raney Ni in catalytic

hydrogenation are tedious conditions, use of highly flammable

molecular hydrogen, high pressure and expensiveness. On the

other hand, supported catalysts for the reduction of

nitroarenes with high intrinsic activity suffers from non-

selective hydrogenation leading to undesired by-products and

difficult purification.5Therefore there is a demand for more

selective, faster and appropriate method for the reduction of

R-NO2 to R-NH2.

In order to control the high cost and unavailability

associated with these metal catalysts, much attention has

been paid to an economical and robust catalyst as an alternate

by using nanoparticles of abundant metal such as Co, Fe, Cu or

Ni.6 The Co nanoparticles have gained much interest due to its

magnetic nature and wide applications in catalysis, dye

adsorption, MRI, biotechnology and data storage.1f,6a,7The

construction and employment of magnetic nanoparticles

(MNPs) guaranteed non-toxic, easily accessible and smooth

reproducibility.8 Additionally, the movement and specificity of

nano-catalysts can be manipulated by their shell

modifications.9Not only metallic cobalt but cobalt oxides have

extensive applications in high density magnetic recording,

sensors and heterogeneous catalysis. Co and cobalt oxide have

electronic configuration dn (n=5 to 9) active for catalytic

reduction of nitro compounds to amines.10 The oxides with dn

configuration induce reduction by relying electron form the

BH4- to the nitro-compounds once they get adsorbed on the

metal surface. According to the previous literature reports

surface positive charge of the dn elements having p-type

semiconductor properties facilitate interaction between metal

surface and donor BH4- ions.10 b

To the best of our knowledge transformation of M1 and

M2 to their respective amines by cobalt based nanocomposite

Page 1 of 8 RSC Advances

RS

CA

dvan

ces

Acc

epte

dM

anus

crip

t

Publ

ishe

d on

27

May

201

6. D

ownl

oade

d by

IIT

Ind

ore

, Cen

tral

Lib

rary

on

02/0

6/20

16 0

5:28

:29.

View Article OnlineDOI: 10.1039/C6RA12920J


ARTICLE Journal Name

2 | J. Name., 2012, 00, 1-3 This journal is © The Royal Society of Chemistry 20xx



(CoNC) have not been investigated under atmospheric reaction

conditions using NaBH4 as reducing agent.

Till dates 2-nitrotriptycene (M1) and 2,6,14-

trinitrotriptycene (M2) are transformed to their respective

amines only by using either Raney Ni or Pd/C or SnCl2/HCl

catalyst under drastic conditions (Scheme 1).11

Conditions: For M1; Raney Ni, N2H4/THF, N2, 60ᵒC, 90 min. For M2;

Raney Ni, N2H4/THF, N2, 60ᵒC, 6-16h or Pd/C,N2H4/EtOH, Reflux, 12h or

SnCl2.2H2O, HCl/ H2O/ EtOH, 100ᵒC, 24h.

Scheme 1 Reduction of M1 and M2 to their respective amines (1 and 2) using

Raney Ni, Pd/C, SnCl2 reported so for.11

Results and Discussion

The present work reports the synthesis and

characterization of novel cobalt/cobalt oxide nanocomposite

(CoNC). The CoNC was derived from recently reported

monomeric Co(II) complex, [CoII(hep-H)(H2O)4]SO4 (A) (Scheme

2) as a single source molecular precursor (SSMP) by a facile

method in aqueous media in the presence of NaBH4 at room

temperature (Scheme 2).12

Scheme 2 General scheme for the synthesis of molecular

precursor and CoNC.

Physicochemical characterization of CoNC was performed

by PXRD, TEM, SEM, EDAX, and XPS.13The crystallinity and

phase purity of the material was determied using powder X-

ray diffraction. X-ray diffraction pattern shows weakly

crystalline to amorphus nature of the catalyst (Fig. S1).

Fig. 1 TEM images of CoNCs; (A) 100 nm magnification; (B) 5 nm magnification

(C) SAED pattern.

TEM analysis shows that the primary CoNC are less than 5

nm in diameter. These primary nanoparticles aggregated to

form secondary particles with capsule like structure having size

100-150 nm (Fig. 1A and B). Selected area electron diffraction

SAED performed on samples of nanopartiles aggregrate

obtained from HR-TEM showed a concentric and quite diffused

ring pattern indicating weakly crystalline nature of the material

(Fig. 1C). The capsule like structure was further confirmed by

SEM images as shown in Fig.S2 a-e.

The newly developed CoNC was employed as a catalyst

towards the hydrogenation of 2-nitrotriptycene (M1) and

2,6,14-trinitrotriptycene (M2) in presence of NaBH4 under

ambient conditions (Scheme 3). M1 and M2 were prepared by

following the previously reported methods.11a Catalytic

conversion of M1 was established to proceed via the

azoxytriptycene intermediate (III) (see later). No reaction was

detected in the absence of hydrogen source or CoNC. The

hydrogenation process was monitored by 1H NMR at regular

intervals of 10 mins and 5 mins for M1 and M2, respectively at

room temperature (Fig.S3 and S4). Further, the evaluation of

solvent on the hydrogenation process established that

dichloromethane (DCM) (Table 1, entry 1, Table S1) was the

best choice, leading to 95% conversion of M1 and M2 to 1 and

2 at 60 and 30 min respectively. The superior catalytic activity

of DCM as compared to ether and ethylacetate was due to its

higher polarity and solubility of the reactant in the following

order DCM>ethyl acetate> ether. To our surprise, moderate

conversion of M1/M2 to 1/2 was also observed in water

because of lower solubility of the nitrotriptycene played a

detrimental role in product selectivity, inspite of higher

polarity of water molecule.

Page 2 of 8RSC Advances

RS

CA

dvan

ces

Acc

epte

dM

anus

crip

t

Publ

ishe

d on

27

May

201

6. D

ownl

oade

d by

IIT

Ind

ore

, Cen

tral

Lib

rary

on

02/0

6/20

16 0

5:28

:29.



Journal Name ARTICLE




Scheme 3 Nirotriptycene reduction catalysed by NaBH4 and CoNC.

Table 1. Effect of solvent on catalytic performance of CoNC for reduction of M1

and M2.

The comparison relating to the reaction conditions between

the reported Raney-Ni or Pd/C or SnCl2 and CoNC as the

catalysts for the hydrogenation of M1/M2 (Table 2) revealed

the superiority of the latter.

Table 2. Superiority of CoNC over other reported catalyst.

The careful monitoring of the reduction of M1 by CoNC via

thin layer chromatography (TLC) facilitated the isolation and

structural characterization of the intermediate azoxytriptycene

(III) which in turn extended the mechanistic outlook of the

transformation process.

Mechanism for nitro reduction is similar to the proposed

mechanism for Cu nanoparticles as reported earlier.14aLike

other metals cobalt is a good conductor of electrical

conductivity facilitating easy electron transfer from adsorbed

species on its surface to another. This property makes CoNC an

excellent catalyst for nitro reduction. Probable mechanism for

the reduction of nitro compounds by NaBH4 and CoNC has

been discussed.

XPS analysis was performed to obtain the elemental

composition and chemical and electronic state of CoNC (Fig. 2,

S5 E-H). All the binding energies were calibrated using the C 1s

peak at 284.6 eV. Formation of metallic Co nanoparticle was

confirmed by the presence of peak at 778 eV. Presence of

peaks at 781.6 eV, 793.2 eV and 787 eV was due to 2p3/2, 2p1/2

and a satellite peak respectively confirms presence Co2+

oxidation state. The aforementioned results show that

complex A is reduced to metallic Co and its oxides CoO or

Co2O3. Presence of peak at 532.6 eV in both fresh and spent

catalyst confirmed the presence of O1s (Fig. S5 G-H).14b,c

Reduction of complex A with NaBH4 results in the formation of

CoNC. Metallic Co nanoparticle present in CoNC catalyzed

nitrotriptycene reduction according to classical Langmuir-

Hinshelwood model and is depicted in Chart 1A. BH4− and 2-

nitrotriptycene sequentially get adsorbed on the CoNC surface.

The adsorption of the nitrotryptecene is followed by transfer

of surface-hydrogen species and electrons (reduction) from

BH4− to 2-nitrotriptycene on its surface to furnish 2-

aminotripticyene.

Fig. 2 XPS spectra; (A) fresh CoNC; (B) Co present in CoNC; (C) spent CoNC; (D)

Co present in spent CoNC.

During the catalytic hydrogenation process, the formation

of Co2O3 or Co3O4 composite via partial oxidation of metallic

Co nanoparticles in the alkaline media was also observed. XPS

analysis of the spent catalyst did not show appearance of any

peak at 778 eV confirming that there was oxidation of metallic

Co nanoparticles to Co2+ during the reaction. Oxidation of

cobalt nanoparticles was further confirmed by SEM-EDAX

analysis. EDAX of fresh and spent catalyst show presence of

Co: O atomic ratio 65.59: 34.51 and 35.08: 64.08 respectively

further confirm oxidation of metallic cobalt and cobalt oxide to

their higher oxidation state (Fig.S2 d-e and S6 c-d). This results

metal oxide nanocomposite having p-type semiconductor

properties. Plausible mechanism for reduction of M1 to 1 on

Entry Solvent

Catalyst

(Mol%)

(CoNC)

1 2

Yield

(%) Time(min)

Yield

(%) Time(min)

1. DCM 5 95 60 95 30

2. EtOAc 5 73 70 82 70

3. Ether 5 61 70 90 70

4. Water 5 30 240 66 180

Substrate Conditions Catalyst Yield

(%) Ref.

M1

N2H4, THF, 60°C,

N2, 1.5h Raney Ni 75 11a

NaBH4, DCM, RT,

Air, 60 min CoNC 95

This

work

M2

N2H4, THF,

60°C,N2,

6-16h

Raney Ni >90 11b-d

N2H4, EtOH,

Reflux,12h Pd/C 88-90 11e-g

HCl,

H2O/EtOH,100°C

24h

SnCl2.2H2O 57 11h

NaBH4, DCM, RT,

Air,30 min CoNC 95

This

work


RS

CA

dvan

ces

Acc

epte

dM

anus

crip

t

Publ

ishe

d on

27

May

201

6. D

ownl

oade

d by

IIT

Ind

ore

, Cen

tral

Lib

rary

on

02/0

6/20

16 0

5:28

:29.








RS

CA

dvan

ces

Acc

epte

dM

anus

crip

t

Publ

ishe

d on

27

May

201

6. D

ownl

oade

d by

IIT

Ind

ore

, Cen

tral

Lib

rary

on

02/0

6/20

16 0

5:28

:29.







(Scheme 4 and Table S1) using a wide variety of solvents such

as DCM, EtOAc, Ether, water and MeOH.

Scheme 4 Reduction of other polyaromatic nitro compounds.

Very high conversion and selectivity was obtained for

various polyaromatic nitro compounds in varying solvents

(Supporting information Table S1, entry no. 3-8). The reaction

was observed in all studied solvents with higher conversion

and good selectivity for entry no 7 except water. In case of

entry no 8, MeOH and Ether gave 99% of conversion while

others have either average conversion or poor. Moreover,

other substituted polyaromatics compounds having amino,

methyl and methoxy functionalities (Table S1, entry no. 5-6, 8,

10) show high conversion (75-99%) and selectivity. However,

the product yield for 9 and 10 was slightly lower with 70 and

75 % respectively. However, DCM and MeOH are compatible

for almost all the polyaromatics nitro and other substituted

compounds. High polarity of DCM and MeOH as well as better

solubility of polyaromatic nitro compounds in these solvents as

compared to other solvents was responsible for superior

catalytic performance of CoNC. This facile reduction of

compounds was obtained at RT leading to the formation of

their respective amines with high conversion in the range of

70-99 % (Table S1, Fig.S10-S17).

Conclusions

To summarize, CoNC was prepared by reduction of single

source molecular precursor (SSMP) A using NaBH4 as reducing

agent. CoNC was characterized by using several

physicochemical techniques and used for the reduction of M1.

Powder XRD spectra indicated formation of weakly crystalline

to amorphous material. HRTEM images and SAED pattern

further corroborate the XRD data. Elemental analysis

performed using XPS spectroscopy of CoNC revealedthe

formation of metallic cobalt and cobalt oxide. The superior

catalytic feature of the newly developed CoNC with well define

morphology for the reduction of polyaromatic nitro

compounds including M1 and M2 as compared to the

reported Raney-Ni, Pd/C and SnCl2 based catalysts was

established. Solvent effect was also investigated for M1

because DCM was found to be best solvent for M1 reduction

to 1. Furthermore, the probable outlook of the reaction

pathways was established via the structural characterization of

the azoxytriptycene intermediate, (III). The scope of the

catalytic material (CoNC) was tested for other polyaromatic

nitro compounds. CoNC with magnetic properties can be

considered as a promising synthon for other potential

applications.

Experimental Section Materials: Commercially available starting materials,

CoSO4·7H2O, 2-(2-hydroxyethyl) pyridine (hep-H), sodium

borohydrate (NaBH4), nitro compounds and reagent grade

solvents were used as received. The model substrates (M1 and

M2) are synthesized according to previous reported literature.

All the reagents were of analytical grade and used without

further purification.

Physical characterizations: Powder X-ray diffraction studies

were carried out on Rigaku SmartLab X-ray diffractometer

using CuKα radiation (1.54 Å). FE-SEM attached with EDAX was

done using Supra55 Zeiss Field-Emission Scanning Electron

Microscope. Transmission Electron Microscopy was carried on

FEI Tecnai G2 12 Twin TEM. XPS analysis of fresh and spent

CoNC was performed using X-ray Photoelectron Spectroscopy

(XPS) with Auger Electron Spectroscopy (AES) Module:

Model/Supplier:PHI 5000 Versa Prob II,FEI Inc.1H NMR spectra

were recorded on BrukerAvance(III) 400MHz spectrometer.

Mass analysis was carried on Brucker-Daltonics, micrOTOF-Q II

mass spectrometer. Single-crystal X-ray structural studies were

performed on Supernova Agilent X-ray diffractometer.

X-ray Crystallographic determination:Single crystal X-ray

structural studies of compounds (2 and III) were performed on

a CCD equipped SUPERNOVA diffractometer from Agilent

Technologies with a low-temperature attachment.2 and III

crystals were weakly diffracting in nature, III shows highly

disorder molecule, which were refined with model atoms for

two positions. Data for 2 and III were collected at 293(2)K

using Cu Kα radiation λα = 1.5418 Å. The strategy for the data

collection was evaluated by using the CrysAlisPro CCD

software. The data were collected by the standard 'phi-omega

scan techniques, and were scaled and reduced using

CrysAlisPro RED software. The structures were solved by direct

methods using SHELXS-97 and refined by full matrix least

squares with SHELXL-97, refining on F2.15The positions of all

the atoms were obtained by direct methods. All non-hydrogen

atoms were refined anisotropically. The remaining hydrogen

atoms were placed in geometrically constrained positions and

refined with isotropic temperature factors, generally 1.2 x

Ueqof their parent atoms. All the H-bonding interactions,

mean plane analyses, and molecular drawings were obtained

using the program Diamond (ver. 2.1d). The crystal and

refinement data are summarized in Table S2‡ and hydrogen

bonding parameters are shown in Table S3.

Preparation of single source molecular precursor: Co(II)

complex, [CoII(hep-H)(H2O)4]SO4 (A), has been synthesized

using the previously reported procedure.12

Procedure for the synthesis of CoNC: In the typical synthesis

of CoNC, 1mmol of the precursor was dissolved in 20 ml of

distilled water and stir for 5 min. Aqueous solution of NaBH4

was added to reaction mixture drop wise till the evolved

hydrogen discontinued. The color change from orange to black


RS

CA

dvan

ces

Acc

epte

dM

anus

crip

t

Publ

ishe

d on

27

May

201

6. D

ownl

oade

d by

IIT

Ind

ore

, Cen

tral

Lib

rary

on

02/0

6/20

16 0

5:28

:29.







was observed as NaBH4solution added. Finally the product was

washed repeatedly with water and ethanol to remove

unreacted materials.

Procedure for catalytic reduction: CoNC (5 mol%) was taken

in glass vial, followed by the addition of 5ml of solvent and

0.1mmol of nitro compound and aqueous NaBH4 (10

equivalent), reaction was magnetically stirred at RT in air for

the desired time duration. The progress of the reaction was

monitored by TLC. After completion of the reaction, the

product was isolated by normal workup procedures.

Acknowledgements

The authors are grateful to CSIR, New Delhi and IIT Indore for funding. We are also grateful to Dr. Sampak Samanta for his support and Advanced Imaging Center, for extending the TEM facility and Advanced Center for Materials Science (ACMS) for XPS, IIT Kanpur. A. M. and V. M. are grateful to MHRD, Government of India for research fellowship and SIC, IIT Indore for providing the characterization facility. V. M. also thanks CSIR, New Delhi for senior research fellowship.

Notes and references

‡Crystal data for 2: C21H19Cl2N3, M = 384.29, monoclinic P21 /n, Z= 4, T= 293(2) K, F(000)= 800, a= 12.084(6)Å, b= 9.0350(12)Å, c= 17.401(6)Å, α = γ= 90°, β= 100.28(3)°, V = 1869.3(11) A3 , Dc = 1.366 mg m−3 , μ(Cu Kα) = 3.188 mm−1 , size = 0.330 x 0.260 x 0.210 mm3 , GOF = 1.076, reflections collected/unique, 3830 / 1132 [R(int) = 0.0352] R1 [I > 2σ(I)] = R1 = 0.0812, wR2 = 0.2345, R indices (all data) ) R1 = 0.0850, wR2 = 0.2400. CCDC no. 1422762. Crystal data for III: C40H26N2O, M = 550.63, triclinic, Pī, Z = 1, T = 293(2) K, F(000) = 576, a =10.6315(7) Å, b=11.8390(9) Å, c=12.1481(8) Å, α = 87.279(6)°, β = 68.228(6)°, γ = 86.725(6)°, V = 1417.08(18) A3 , Dc = 1.290 mg m−3 , μ(Cu Kα) = 0.602 mm−1 , size = 0.210 x 0.170 x 0.130 mm3,GOF = 1.027, reflections collected/unique, 9377 / 5357 [R(int) = 0.0223] R1 [I > 2σ(I)] = R1 = 0.0527, wR2 = 0.1382 , R indices (all data) R1 = 0.0699, wR2 = 0.1545. CCDC no. 1422763. Supporting content:Experimental details, characterization images, spectral data (Fig. S10-S17) and video for catalyst separation attached and crystallographic details can be found in supporting information. 1 (a) N. Yan, C. Xiao and Y. Kou, Coord. Chem. Rev.,2010, 254,

1179-1218; (b) J. Fang, B. Zhang, Q. Yao, Y. Yang, J. Xie, N. Yan, Coord. Chem. Rev., 2016, 322, 1-29 (c) N. Yan, Y. Yuan and P. J. Dyson, Dalton Trans., 2013, 42, 13294-13304. (d) M. Shokouhimehr, J. E. Lee, S. I. Han and T. Hyeon, Chem.

Commun., 2013, 49, 4779-4781; (e) Y. Lin, S. Wu, W. Shi, B. Zhang, J. Wang, Y. A. Kim, M. Endod and D. S. Su, Chem. Commun.,2015, 51, 13086-13089; (f) V. Udumula, J. H. Tyler, D. A. Davis, H. Wang, M. R. Linford, P. S. Minsonand D. J. Michaelis, ACS Catal.,2015, 5, 3457-3462.

2 (a) C. Yu, B. Liu and L. Hu, J. Org. Chem.,2001,66, 919-924; (b) A. Saha and B. Ranu, J. Org. Chem.,2008, 73, 6867-6870; (c) X. -B. Lou, L. He, Y. Qian, Y. -M. Liu, Y. Cao and K.-N. Fan, Adv. Synth. Catal.,2011, 353, 281-286; (d) X. Liu, S. Ye, H.-Q. Li, Y. -M. Liu, Y. Cao and K.-N. Fan, Catal. Sci. Technol.,2013, 3, 3200-3206; (e) C. Srilakshmi, H. V. Kumar, K. Praveena, C.

Shivakumara and M. M. Nayak, RSC Adv.,2014, 4, 18881-18884; (f) R. Easterday, O. Sanchez-Felix, Y. Losovyj, M. Pink, B. D. Stein, D. G. Morgan, M. Rakitin, V. Y. Doluda, M. G. Sulman, W. E. Mahmoud, A. A. Al-Ghamdid and L. M. Bronstein, Catal. Sci. Technol.,2015, 5, 1902-1910.

3 (a) D. V. Jawale, E. Gravel, C. Boudet, N. Shah, V. Geertsen, H. Li, I. N. N. Namboothiri and E. Doris, ChemCommun.,2015, 51, 1739-1742; (b) S. Fountoulaki, V. Daikopoulou, P. L. Gkizis, I. Tamiolakis, G. S. Armatas and I. N. Lykakis, ACS Catal.,2014, 4, 3504-3511; (c) R. K. Rai, A. Mahata, S. Mukhopadhyay, S. Gupta, P.-Z. Li, K. T. Nguyen, Y. Zhao, B. Pathak and S. K. Singh, Inorg. Chem.,2014, 53, 2904-2909.

4 (a) J. Fang, J. Li, B. Zhang, X. Yuan, H. Asakura, T. Tanaka, K. Teramura, J. Xie and N. Yan, Nanoscale, 2015, 7, 6325-6333; (b) B. Sheng, L. Hu, T. Yu, X. Cao and H. Gu, RSC Adv.,2012, 2, 5520–5523; (c) Y.-M. Lu, H.-Z. Zhu, W.-G. Li, B. Hu and S.-H. Yu, J. Mater. Chem., A 2013, 1, 3783-3788; (d) R. J. Rahaim Jr. and R. E. Maleczka Jr., Synthesis,2006, 19, 3316-3340; (e) Y. Lee, S. Jang, C.-W. Cho, J.-S. Bae, S. Park and K. H. Park, J

Nanosci. Nanotechnol.,2013, 11, 7477-7481; (f) C. Antonetti, M. Oubenali, A. M. R. Galletti, P. Serp and G. Vannucci, Appl. Catal., A 2012, 421−422 ,99-107; (g) J. H. Kim, J. H. Park, Y. K. Chung and K. H. Park, Adv. Synth. Catal., 2012, 354, 2412-2418.

5 S. Cai, H. Duan, H. Rong, D. Wang, L. Li, W. He and Y. Li, ACS

Catal., 2013, 3, 608−612. 6 (a) P. Chen, F. Yang, A. Kostka and W. Xia, ACS Catal.,2014,4,

1478−1486; (b) C. Jiang, Z. Shang and X. Liang, ACS

Catal.,2015, 5, 4814−4818; (c) T. Subramanian and K. Pitchuman, ChemCatChem,2012,4,1917–1921; d) R. Dey, N. Mukherjee, S. Ahammed and B. C Ranu, Chem.Commun.,2012, 48, 7982–7984.

7 (a) J.-F. Soulé, H. Miyamura and S. Kobayashi, J. Am. Chem. Soc.,2011, 133, 18550–18553; (b) L. Tang, Y. Cai, G. Yang, Y. Liu, G. Zeng, Y. Zhou, S. Li, J. Wang, S. Zhang, Y. Fang and Y. He, Appl. Surf. Sci.,2014, 314, 746-753; (c) L.-S. Bouchard, M. S. Anwar, G. L. Liu, B. Hann, Z. H. Xie, J. W. Gray, X. Wang, A. Pines and F. F. Chen, Proc. Natl. Acad. Sci.,2009,106, 4085–4089; (d) A.-H. Lu, E. L. Salabas and F. Schüth, Angew. Chem. Int. Ed.,2007, 46, 1222-1244.

8 (a) V. Polshettiwar, R. Luque, A. Fihri, H. Zhu, M. Bouhrara and J. -M. Bassett, Chem. Rev.,2011,111, 3036–3075; (b) K. V. S. Ranganath and F. Glorius, Catal. Sci. Technol.,2011, 1, 13–22; (c) M. B. Gawande, A. K. Rathi, J. Tucek, K. Safarova, N. Bundaleski, O. M. N. D. Teodoro, L. Kvitek, R. S. Varma and R. Zboril, Green Chem.,2014,16, 4137-4143.

9 (a) M. B. Gawande, P. S. Brancoa and R. S. Varma, Chem. Soc. Rev.,2013, 42, 3371-3393; (b) A. Fihri, M. Bouhrara, U. Patil, D. Cha, Y. Saih and V. Polshettiwar, ACS Catal.,2012,2, 1425-1431; (c) N. Shah, E. Gravel, D. V. Jawale, E. Doris and I. N. N. Namboothiri, ChemCatChem,2015, 7, 57-61; (d) N. Shah, E. Gravel, D. V. Jawale, E. Doris and I. N. N. Namboothiri, ChemCatChem,2014, 6, 2201-2205.

10 (a) F. A. Westerhaus, R. V. Jagadeesh, G. Wienhöfer, M.-M. Pohl, J. Radnik, A.-E. Surkus, J. Rabeah, K. Junge, H. Junge and M. Nielsen, Nat. Chem.,2013, 5, 537-543; (b) H. Ma, H. Wang, T. Wu and C. Na, Appl. Catal., B,2016, 180, 471-479; (c) N. Yan, Z. Zhao, Y. Li, F. Wang, H. Zhong and Q. Chen, Inorg. Chem.,2014, 53, 9073-9079; (d) X.-W. Wang, K.-L. Wu, K. Liu, W.-Z. Wang, Y.-X. Yue, M.-L. Zhao, J. Cheng, J. Ming, X.-W. Wei and X.-W. Liu, CrystEngComm,2015, 17, 734-739; (e) H. Li, J. Liao and T. Zeng, Catal. Sci. Techol.,2014, 4, 681-687; f) J. M. Song, S. S. Zhang and S. H. Yu, Small,2014, 10, 717-724

11 (a) J. H. Chong and M. J. MacLachlan, Inorg. Chem.,2006, 45, 1442-1444; (b) C. Zhang and C.-F. Chen, J. Org. Chem.,2006, 71, 6626-6629; (c) X. Zhu, C.-L. Do-Thanh, C. R. Murdock, K. M. Nelson, C. Tian, S. Brown, S. M. Mahurin, D. M. Jenkins, J.


RS

CA

dvan

ces

Acc

epte

dM

anus

crip

t

Publ

ishe

d on

27

May

201

6. D

ownl

oade

d by

IIT

Ind

ore

, Cen

tral

Lib

rary

on

02/0

6/20

16 0

5:28

:29.







Hu, B. Zhao, H. Liu and S. Dai, ACS Macro Lett.,2013, 2, 660-663; (d) M. Carta, M. Croad, K. Bugler, K. J. Msayiba and N. B. McKeown, Polym. Chem.,2014, 5, 5262-5266; (e) T. Bura, F. Nastasi, F. Puntoriero, S. Campagna and R. Ziessel, ChemEurJ.,2013,19, 8900-8912; (f) H-H. Chou, H.-H. Shih and C.-H. Cheng, J. Mater. Chem.,2010, 20, 798-805;(g) Z. Xu, X. Q. Xiong and L. Cheng, Chinese Chem.Lettr.,2008, 19, 1127-1130; (h) S. L. Buchwald, T. M. Swager, G. Teverovskiy and M. Su, PCT Int. Appl.,2014, WO 2014070888 A1.

12 S. M. Mobin and A. Mohammad, Dalton Trans.,2014, 43, 13032–13040.

13 (a) Y.-B. Cao, X. Zhang, J.-M. Fan, P. Hu, L.-Y. Bai, H.-B. Zhang, F.-L.Yuan and Y.-F. Chen, Cryst.Growth Des.,2011, 11, 472-479; (b) H. P. Singh, S. Sharma, S. K. Sharma and R. K. Sharma, RSC Adv.,2014, 4, 37816-37825; (c) R. Das, P. Pachfule, R. Banerjee and P. Poddar, Nanoscale,2012, 4, 591-599; (d) X. Liang an L. Zhao, RSC Adv., 2012, 2, 5485–5487.

14 (a) A. K. Sasmal, S. Dutta and T. Pal, Dalton Trans.,2016, 45, 3139-3150; (b) G. Kwak, J. Hwang, J.-Y. Cheon, M. H. Woo, K.-W. Jun, J. Lee and K.-S. Ha, J. Phys. Chem. C,2013, 117, 1773-1779; (c) M. C. Biesinger, B. P. Payne, A. P. Grosvenor, L. W. Lau, A. R. Gerson and R. S. C. Smart, Appl. Surf.

Sci.,2011, 257, 2717-2730. 15 G. M. Sheldrick, Acta Crystallogr. Sect.,A2008, A64, 112−122;

G. M. Sheldrick,Shelx97, Program for Crystal Structure Solution and Refinement; University of Göettingen: Göettingen, Germany, 1997.


RS

CA

dvan

ces

Acc

epte

dM

anus

crip

t

Publ

ishe

d on

27

May

201

6. D

ownl

oade

d by

IIT

Ind

ore

, Cen

tral

Lib

rary

on

02/0

6/20

16 0

5:28

:29.



Reduction of selective polyaromatic nitrotriptycene via azoxytriptycene

intermediate under ambient conditions using cobalt/cobalt oxide

nanocomposite (CoNC)

Selectively targeted polyaromatic 2-nitrotriptycene (M1) and 2,6,14-trinitrotriptycene (M2) were

chosen as model substrates for demonstrating catalytic hydrogenation at ambient conditions

using cobalt/cobalt oxide based nanocomposite (CoNC) as catalytic material. Conventionally

Raney Ni or Pd/C or SnCl2/HCl is used as catalyst under drastic conditions. CoNC can be used

as an alternative catalyst with superior catalytic performance at ambient conditions. Interestingly,

mechanistic path is confirmed by single crystal X-ray structure of azoxytriptycene, (III).


RS

CA

dvan

ces

Acc

epte

dM

anus

crip

t

Publ

ishe

d on

27

May

201

6. D

ownl

oade

d by

IIT

Ind

ore

, Cen

tral

Lib

rary

on

02/0

6/20

16 0

5:28

:29.



view article online rsc advancesiiti.ac.in/people/~xray/rsc adv.pdfcatalyst such as au, pd, pt, rh,...

Documents