COMMUNICATION
DOI: 10.1002/chem.201202380
Regio- and Chemoselective Reduction of Nitroarenes and Carbonyl
À
Compounds over Recyclable Magnetic Ferrite Nickel Nanoparticles
À
(
Fe O Ni) by Using Glycerol as a Hydrogen Source
3
4
[
a]
[b]
[a]
[c]
Manoj B. Gawande,* Anuj K. Rathi, Paula S. Branco,* Isabel D. Nogueira,
[
d]
[e]
[e]
Alexandre Velhinho, Janhavi J. Shrikhande, Utkarsha U. Indulkar,
Radha V. Jayaram, C. Amjad A. Ghumman, Nenad Bundaleski, and
[
e]
[f]
[f]
[
f]
Orlando M. N. D. Teodoro
Functionalized magnetic nanoparticles (MNPs) have
emerged as viable alternatives to conventional materials, not
just for heterogeneous, but also for homogenous catalysis
with high turnover number (TON) and excellent selectivi-
[3c,6a,b]
ty.
Reduction of organic substrates such as nitro, azido,
[1]
[2]
and carbonyl compounds is of the utmost importance in or-
[6c]
because they offer an added advantage of being magnetical-
ly separable, thereby eliminating the requirement of catalyst
filtration. A variety of catalytic systems involving metal-sup-
ported MNPs have been devised and used in synthetic or-
ganic synthesis. This is a fundamental process with a vari-
ety of applications in pharmaceutical industries and in the
[6d]
synthesis of biologically significant compounds.
There
have been a number of reports on hydrogenation reactions
[3]
[7]
ganic reactions. For example, immobilized palladium com-
plexes with N-heterocyclic carbene ligands (NHC-Pd com-
plexes) on the surface of ferrite-MNPs were used for palla-
using noble metal catalysts, however these catalysts pres-
ent as a major drawback its high cost. Recently remarkable
economic non-toxic and effective iron nanoparticles cata-
[2d]
[8]
dium cross-coupling reactions. A more demanding proto-
col for the preparation of palladium nanoparticles supported
on phosphate-functionalized MNPs was reported by Ying-
huai and co-workers with success on Suzuki- and Heck cou-
lysts were reported for specific reduction. Recently, glycer-
ol has gained increasing attention as an alternative sustaina-
ble solvent for catalytic and non-catalytic organic transfor-
[9]
mations because of its unique combination of physical and
chemical properties, such as polarity, low toxicity, high boil-
[4]
pling reactions. Xia et al., used a magnetically separable
Pd/Fe O catalyst for a carbonylative Sonogashira coupling
[10]
ing point, and biodegradability. Very recently, glycerol has
3
4
[
5]
[11]
reaction. Free nano-g-Fe O have been shown to be active,
also been used in transfer hydrogenation reactions.
The
2
3
[12]
stable, and highly selective catalysts for various oxidations
reduction of nitro as well as carbonyl compounds with hy-
drogen-transfer reagents is a much safer and more benign
process than reactions involving molecular hydrogen, metal
hydrides, or soluble metals. Varma and Manorama already
addressed this issue by using palladium or nickel on dopa-
mine-terminated surface of Fe O for hydrogenation reac-
[
a] Dr. M. B. Gawande, Prof. Dr. P. S. Branco
REQUIMTE, Departamento de Quꢀmica
Faculdade de CiÞncias e Tecnologia
Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)
Fax : (+351)21-2948550
3
4
[3f,13]
tions.
The complexes of the second- or third-row transi-
E-mail: m.gawande@fct.unl.pt
[14]
[15]
[16]
[17]
tion metals, such as Rh, Ru, Ir, and Pt are among
the most efficient catalysts devised. Much less attention has
been devoted to the hydrogen-transfer reduction of carbonyl
compounds using inexpensive metals. In continuation of our
[
[
b] Dr. A. K. Rathi
Jubilant Chemsys Ltd., B-34, Sector-58
Noida-201301, New Delhi (India)
[18]
efforts to develop protocols for green raw materials and
[
c] Dr. I. D. Nogueira
heterogeneous catalysis for hydrogen-transfer reactions and
Instituto de CiÞncia e Engenharia de Materiais e Superfꢀcies
IST, Lisbon (Portugal)
[19]
nano-catalysis,
we propose to use glycerol as hydrogen
donor as well as solvent in the reduction of nitro and car-
bonyl compounds using a new, efficient, recyclable, and in-
expensive ferrite-nickel magnetic-nanoparticles (Fe O -Ni
d] Prof. Dr. A. Velhinho
CENIMAT/I3N Departamento de CiÞncias dos Materiais
Faculdade de CiÞncias e Tecnologia
Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)
3
4
MNPs). This protocol avoids multistep processes and link-
[
e] Dr. J. J. Shrikhande, Dr. U. U. Indulkar, Prof. Dr. R. V. Jayaram
Department of Chemistry, ICT, Matunga, Mumbai (India)
[20]
ers between the metal and ferrites rendering the present
protocol cost-effective.
[
f] Dr. C. A. A. Ghumman, Dr. N. Bundaleski, Prof. O. M. N. D. Teodoro
Centre for Physics and Technological Research (CeFITec)
FCT, UNL, Lisboa (Portugal)
Fe O -Ni MNPs were prepared by the simple wet impreg-
3
4
[5,19g,h,21]
nation method followed by chemical reduction
Scheme 1) and characterized by X-ray diffraction (XRD),
inductive coupled plasma-atomic emission spectroscopy
(
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/chem.201202380.
Chem. Eur. J. 2012, 00, 0 – 0
ꢁ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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