Trans(Cl)-2,2′-bipyridinedicarbonyldichlororuthenium(II) complex catalyzed oxidation of olefins, aryl hydrocarbons and alcohols in homogeneous phase

Article abstract of DOI:10.1016/j.jics.2021.100012

Catalytic oxidation of organic substrates has wide applications in chemical industries due to which huge extensive research work is continuously going on throughout the world. Present study reports efficacious use of Trans (Cl)-2,2′-bipyridinedicarbonyldichlororuthenium(II) complex catalyzed oxidation of internal and terminal olefins, aryl hydrocarbons and alcohols. CH2Cl2–C2H5OH (6:4) was suitable solvent system for these oxidation reactions. The normal pressure oxidation reaction has been carried out at 1 ?atm. Pressure of oxygen and at 300C. The high pressure oxidation reaction was done at 4.48 ?× ?103 KNm3 pressure of oxygen and at 600C. No diminished catalytic activity was observed while checking the recyclability of catalyst up to 6–8 catalytic runs. Catalytic activity was also investigated using tert-butyl hydroperoxide as oxidant inspite of di-oxygen. Effect of different parameters on the rate of oxidation was also studied i.e. extra ligand, temperature, solvents, acids and bases. Kinetic studies have been done and on the basis of kinetics, the mechanism is proposed.

Full text of DOI:10.1016/j.jics.2021.100012

Journal of the Indian Chemical Society 98 (2021) 100012
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Trans(Cl)-2,20-bipyridinedicarbonyldichlororuthenium(II) complex
catalyzed oxidation of olefins, aryl hydrocarbons and alcohols in
homogeneous phase
,
*
Varsha Sharma a, Bhawana Pant b, Deep Prakash b, Priyanka Sagar b
a Department of Chemistry, S.S.Jain Subodh P.G. (autonomous) College, Jaipur, India
b Department of Chemistry, S.S.J.Campus, Kumaun University, Uttarakhand, India
A R T I C L E I N F O
A B S T R A C T
Keywords:
Catalytic oxidation of organic substrates has wide applications in chemical industries due to which huge extensive
research work is continuously going on throughout the world. Present study reports efficacious use of Trans (Cl)-
2,20-bipyridinedicarbonyldichlororuthenium(II) complex catalyzed oxidation of internal and terminal olefins, aryl
hydrocarbons and alcohols. CH2Cl2–C2H5OH (6:4) was suitable solvent system for these oxidation reactions. The
normal pressure oxidation reaction has been carried out at 1 atm. Pressure of oxygen and at 300C. The high
pressure oxidation reaction was done at 4.48 ꢀ 103 KNm3 pressure of oxygen and at 600C. No diminished
catalytic activity was observed while checking the recyclability of catalyst up to 6–8 catalytic runs. Catalytic
activity was also investigated using tert-butyl hydroperoxide as oxidant inspite of di-oxygen. Effect of different
parameters on the rate of oxidation was also studied i.e. extra ligand, temperature, solvents, acids and bases.
Kinetic studies have been done and on the basis of kinetics, the mechanism is proposed.
Ru(II) complexes
Catalytic oxidation
Internal and terminal olefins
Aryl hydrocarbons
Alcohol
1. Introduction
Various oxidation states carried by transition metals make them
feasible to interact with di-oxygen, sometimes so readily that the metal-
Homogeneous catalytic reactions in solutions are commonly very
complex and proceed by the way of linked chemical reactions in a closed
cycle involving different species. Homogeneous catalysis by coordination
compounds continues to be an active and fruitful area of research. A very
useful application of homogeneous catalysis in chemical industries is
catalytic oxidation. Oxidation is extensively used in laboratories scale
synthesis of fine organic chemicals as well as in the manufacturing of
large volume of petrochemicals. Catalytically oxidized products of
various organic compounds perceive extensive applications in chemical
industries [1–10]. Industries are producing million tonnes of valuable
polymers and solvents by using ethanal, p-xylene, toluene, benzene as
starting material and ultimately these starting materials are produced via
the catalytic oxidation of mentioned substrates [2–4]. An important in-
dustrial process i.e. the manufacturing of adipic acid and caprolactum
involves the use of cyclohexanol, cyclohexanone etc. which eventually
produced by catalytic oxidation of cyclohexane. By using this catalytic
process Dupont, ICI, DSM etc. are marketing more than 6–8 millon tones
of adipic acid (Nylon-6) and caprolactum (Nylon-6-6) per year [an
Ulmanns Encyclopedia by Verlag Chemie 1972–1983].
oxygen adducts can also be isolated [11–17]. Every form of Metals
weather in metallic or in complex or in any type of metallic salt is
commonly used as catalyst for the oxidation of different organic sub-
strates [18–23]. Large numbers of non-orthometallated and orthome-
tallated complexes of Pd(II) and Rh(I) shows efficient catalytic activity
towards oxidation of a long range of organic compounds [24–39].
Sterically hindered cis-[Ru(dmp)2(S)2(PF)6] was used for the catalytic
oxidation of norbornene with dioxygen. A free radical reaction mech-
anism is established in between norbornene, cis-[Ru(dmp)2(S)2(PF)6]
and oxygen [2]. H2O2, iodosylbenzene, tert-butylhydrogenperoxide
and pyidine-N-oxide etc. can also been used as co-oxidants or oxi-
dants in place of molecular oxygen [40,41]. In spite of large work on
catalytic oxidation reaction still homogeneous catalytic oxidation re-
action has several limitations. So it is needed to be introducing some
environmental friendly economically viable catalyst for these reactions
[42].
In the present study trans (Cl)- [RuII(bpy)(CO)2Cl2] complex was
used as catalyst for the catalytic oxidation of internal olefins, terminal
olefins, arylhydrocarbons and alcohols. A kinetics study reveals that the
* Corresponding author.
E-mail address: sagarpriyanka2006@gmail.com (P. Sagar).
https://doi.org/10.1016/j.jics.2021.100012
Received 27 November 2020; Accepted 29 January 2021
0019-4522/© 2021 Indian Chemical Society. Published by Elsevier B.V. All rights reserved.

V. Sharma et al.
Journal of the Indian Chemical Society 98 (2021) 100012
reaction mechanism follows the coordination of metal oxygen and metal
olefins rather than free radical mechanism.
evaporated oxygen activated catalytic mixture showed peak at 870 cmꢂ1
indicates the formation of metal peroxide in the oxidation process which
further confirmed the involvement of metal oxygen coordination in these
catalytic oxidation processes. The partial displacement of bidentate
ligand to accommodate substrate molecule as shown in the reaction
mechanism has also been found in the literature [44].
In the study of preferential oxidation of styrene in presence of cis-
stilbene, the oxidation of later was started only after the 90% conversion
of previous one respectively. In case of olefins 1- alkene preferentially
oxidize over 2-alkene due to less steric hindrance. The oxidation of 2-
alkene was always commencing only after the 78% conversion of 1-
alkene.
2. Result and discussion
Trans (Cl)-[RuII(bpy)(CO)2(Cl)2] complex was found moderately
active catalyst for the catalytic oxidation of internal and terminal olefins,
aryl hydrocarbons and alcohols at 1 atmospheric pressure and at 30 ꢁC.
Reaction condition along with initial turn over number, nature and %
yield of products are given in Table .1. Catalytic activity of Trans (Cl)-
[RuII(bpy)(CO)2(Cl)2] complex was found comparatively better when
using tert-butyl hydroperoxide as oxidant in place of dioxygen. Observed
results with other detailed reaction parameters are given in Table .2.
Catalytic activity of Trans(Cl)-[RuII(bpy)(CO)2(Cl)2] complex at high
temperature and pressure of molecular oxygen was found to increase
substantially. High-pressure oxidation reactions for different substrates
are given in Table .3. Nearly more than 92% conversion was found at the
end of each catalytic run. The resulted products for particular substrates
were always found same in all reaction conditions except their rate of
oxidation.
The sequential Mol % of product distribution of catalytic oxidation
run of styrene, benzene and 1-octene are given in Figs. 1–3. According to
Initial rate and initial turn over number the substrates are arranged in the
following manner-
Styrene > cyclohexene > butyl alcohol > benzene > 1-octene > cis-
stilbene > norbornene.
To establish Ru(II) promoted catalytic oxidation, rather than free
radical chain auto-oxidation, analogous runs were also carried out with
4-methyl-2,6-di-t-butylphenol (3.1 ꢀ 10ꢂ2 mol/lit.). Any noticeable
changes were not observed in presence and absence of 4-methyl-2,6-di-t-
butylphenol. Thus the free radical chain reaction mechanism was ruled
out and the involvement of metal oxygen and metal olefins coordinated
mechanism is proposed as already reported elsewhere [43].
It has further observed that in presence of molecular oxygen the
colorless catalytic solution was slightly changed to yellow within 10–15
min. All attempts to isolate the yellow compound in its pure from the
solution were unsuccessful but I.R. spectral analysis of vacuum
3. Material and methods
3.1. Materials and equipments
Throughout the whole investigation analytical grade chemicals were
always used. The solvents were distilled under anaerobic conditions prior
to use and preserved on activated molecular sieves (4A). Ultra pure
quality of N2, Ar and O2 were always use. Analytical data of complexes
were estimated by sending the sample to RSIC Chandigarh. Halogen was
estimated according to literature method [45]. Ruthenium was estimated
spectrophotometrically [46] using 5-nitro-2.4.6-triamino pyrimidino at
pH 1.8. The absorbance was noted at λ max 540 nm. UV/Vis, IR and NMR
spectra were recorded on Pye-Unicam PU-8600, Pye-Unicam SP3-300,
Bruker AC-300F spectrophotometer, respectively. TLC using silica
gel-coated plastic sheets (Merck silica gel F254) and GLC (5700-Nucon
gas chromatograph, using SE-30, Carbowax-20 M or OV-17 column.)
were used to analyze the product mixture. The liquid components of the
product mixture were separated by fractional distillation under reduced
pressure. For the separation of solid components, the residue left after the
removal of solvent was extracted with suitable solvent and the extract
was then passed through 200-mesh silica gel column and eluted with
appropriate solvent. The eluted liquid has evaporated to dryness, the
solid residue was dissolved in alcohol and the components were esti-
mated by GLC.
3.2. Preparation of catalysts
Preparation of trans(Cl)-2,20-bipyridinedicarbonyldichlororuthenium
Table 1
(II) complex trans (Cl)- [RuII(bpy)(CO)2Cl2] {Where bpy
bipyridine}
¼
2,2/-
Catalytic oxidation of organic substrates in CH2Cl2–C2H5OH (6:4) using
trans(Cl)- [RuII(bpy)(CO)2(Cl)2] as catalyst at 1 atm. pressure of molecular ox-
ygen and at 30 0C.
Substrate
[cat.]
(10ꢂ4
mol/
lit.)
[subs]
(mol/
lit.)
Initial turn
over no.
Nature of products with %
yielda
3.2.1. Compound was prepared as per reported method [47]
Methanolic solution (5 ml) of 2,2/pyridine(0.37 g, 2.34 mmol) was
added at room temperature dropwise with constant stirring to meth-
anolic solution (18 ml, pH was adjusted to 7 with triethylamine) of
[Ru(CO)2Cl2]na (0.45 g, 1.95 mmol). After 1 h a copious white cream
precipitate appeared slowly. The precipitate was kept in the reaction
mixture overnight and then filtered, washed first with cold methanol and
then with diethyl ether. Compound was finally dried under vacuum.
Compound was further purified by passing through alumina column
using dichloromethane-methanol (98:2) mixed solvent system as eluent.
(minꢂ1
)
Styrene
11.03
1.31
1.48
4.0
Benzaldehyde
Styrene-oxide
Benzoic-acid
2-cyclohexen-1-ol
2-cyclohexen-1-one
Cyclohexene-oxide
2-octanone
trans-stilbeneoxide
Cis-stilbeneoxide
Benzaldehyde
exo-
47
3.5
1.5
50
8
Cyclohexene
11.03
3.7
6
1-octene
Cis-stilbene
12.98
11.68
0.95
0.84
3.3
0.8
53
30
7
2
10
3.2.2. Yield: 78%
m.p.: 235 ꢁC. Anal.Data found: Cl,17.97; N,7.39; C,36.84; H,2.10,;
Ru,25.92; Calcd: Cl,18.45; N,7.17; C,37.32; H,2.08.,; Ru,26.31.; Mol.Wt.-
Norbornene
Cyclohexane
12.98
12.98
1.59
1.38
0.5
0.2
norborneneoxide
Cyclohexanol
Cyclohexanone
Phenol
Benzaldehyde
Benzoic-acid
p-
35
12
40
47
3
382.28; IR(KBr):
ν
ν
C ¼ O 2068–1980 cmꢂ1 as-OCO 2062–2000 cmꢂ1
; ν ;
Ru-Cl 338 cmꢂ1. UV/Vis(DMF): 19,050 cmꢂ1(d-d transition).
Benzene
Benzyl
alcohol
p-chloro
benzyl
11.68
11.42
1.68
1.44
2.8
2.2
11.42
1.44
2.0
45
3.3. Procedure for oxidation in normal and high pressure condition
chlorobenzaldehyde
alcohol
Normal pressure oxidation and High-pressure oxidation reactions
a
% yield at the end of 8 h.
were carried out according to the procedure described earlier [37–39].
2

V. Sharma et al.
Journal of the Indian Chemical Society 98 (2021) 100012
Table 2
Catalytic oxidation of organic substrates, in presence of tert-butyl hydroperoxide at 1 atm. pressure of argon and at 30 ꢁC using trans(Cl)-[RuII(bpy)(CO)2(Cl)2] as
catalyst.
Substrate
Styrene
[cat.] (10ꢂ4 mol/lit.)
11.03
[subs] (mol/lit.)
1.31
Amount of t-BuOOH (mol/lit.)
9.7
Initial turn over no. (minꢂ1
9
)
Nature of products with % yield
Benzaldehyde
Styrene-oxide
Benzoic-acid
77a
5a
2.5a
65a
6a
Cyclohexene
11.03
1.48
9.62
7
2-cyclohexen-1-ol
2-cyclohexen-1-one
Cyclohexene-oxide
2-octanone
trans-stilbene-oxide
cis-stilbene-oxide
Benzaldehyde
exo-norbornene-oxide
Cyclohexanol
Cyclohexanone
Phenol
5.5a
64a
38b
10b
7b
1-octene
cis-stilbene
12.98
11.68
0.95
0.84
6.65
5.04
6
5
Norbornene
Cyclohexane
12.98
12.98
1.59
1.38
4.54
8.28
3
2.5
15b
30b
8b
Benzene
Benzyl alcohol
11.68
11.42
1.68
1.44
10.08
8.64
5.5
5
49b
55b
4b
Benzaldehyde
Benzoic-acid
p-chloro benzyl alcohol
11.42
1.44
8.64
4
p-chloro-benzaldehyde
52b
a
% yield after 5 h.
% yield after 7 h, medium ¼ CH2Cl2– C2H5OH (6:4).
b
Table 3
Catalytic oxidation of organic substrates in CH2Cl2:C2H5OH (6:4) mixed solvent using trans(Cl)-[RuII(bpy)(CO)2(Cl)2] as catalyst at high pressure of molecular oxygen.
Substrate
[cat.] (10ꢂ4 mol/
lit.)
[subs] (mol/
lit.)
Pressure (103
Temp.
(0C)a
Initial turn over no.
Reaction time
(min)
Nature of products with %
yield
KNmꢂ2
)
(minꢂ1
)
Styrene
5.20
1.31
4.48
50
40
125
Benzaldehyde
Styrene-oxide
Benzoic-acid
91
5
2
Cyclohexene
9.08
1.48
4.14
50
32
125
2-cyclohexen-1-ol
2-cyclohexen-1-one
10
74
Cyclohexene oxide
2-octanone
8
1-octene
cis-stilbene
7.78
9.08
0.95
0.84
4.65
4.83
55
50
23
14
125
180
95
45
15
7
15
91
84
6
trans-stilbene oxide
cis-stilbene oxide
Benzaldehyde
exo-norborneneoxide
Phenol
Norbornene
Benzene
Benzyl alcohol
12.9
9.73
7.78
1.59
1.69
1.44
5.85
5.85
4.48
60
55
60
4
26
28
540a
150
165
Benzaldehyde
Benzoic-acid
p-chloro benzyl
7.78
1.44
4.48
60
20
200
p-chloro
80
alcohol
benzaldehyde
a
After that the rate of conversion was found very-very slow.
Fig. 2. Catalytic oxidation of 1-octene using trans(Cl)-[Ru(bpy)(CO)2(Cl)2] in
CH2Cl2 –C2H5OH (6:4) mixed solvent at 65 ꢁC and 4.65 ꢀ 103 KNmꢂ2 pressure
of oxygen.
Fig. 1. Catalytic oxidation of styrene using trans(Cl)-[Ru(bpy)(CO)2(Cl)2] in
CH2Cl2 –C2H5OH (6:4) mixed solvent at 60 ꢁC and at 4.48 ꢀ 103 KNmꢂ2
pressure of oxygen.
3

V. Sharma et al.
Journal of the Indian Chemical Society 98 (2021) 100012
Sulphonic acid was added to the catalytic reaction mixture in limited con-
centration (0.01 mol/lit.) and the rate of oxidation reactions was found to
increase significantly but beyond this limit the catalytic activity of Ru(II)
complex was found to decrease. Initial addition of the extra ligand (~10ꢂ4
mol/lit) such as triphenyl phosphine, pyridine etc., decreased the rate of
oxidation without changing other conditions and results.
3.5. Recycle of the catalyst
Metal complexes in the reaction mixture was in very low concentra-
tion (5.20 ꢀ 10ꢂ6 to 12.9 ꢀ 10ꢂ6 mol) due to which the attempts to
isolate and analyze the active catalytic species at the end of catalytic run
by removing the solvent, the unreacted substrate and the products were
unsuccessful. Again the active catalytic species was found to undergo
slow decomposition during the process of separation from its concen-
trated solution. However, the catalytic activity of the remaining solution
obtained after the removal of products and the unreacted substrate by
fractional distillation under reduced pressure of nitrogen was found same
to that of original one. Recycling activity of the catalyst was found almost
same even after 6–8 repeated catalytic run.
Fig. 3. Catalytic oxidation of benzene using trans(Cl)-[Ru(bpy)(CO)2(Cl)2] in
CH2Cl2 –C2H5OH (6:4) mixed solvent at 60 ꢁC and 5.85 ꢀ 103 KNmꢂ2 pressure
of oxygen.
3.6. Kinetics
Kinetics studies were carried out mainly with styrene and 1-octene
using trans (Cl)-[RuII(bpy)(CO)2(Cl)2] as catalyst by changing catalyst
concentration (from 5.20 ꢀ 10ꢂ4 mol/lit to 12.98 ꢀ 10ꢂ4 mol/lit),
substrates concentration (from 0.84 to 1.69 mol/lit) and oxygen pressure
(from 200 to 900 mm of Hg). While doing the change in one parameter,
kept other two parameters remain constant. The rate was determined by
estimating the reaction mixture at regular intervals of time with the help
of Nucon-5700 gas chromatograph. Kinetic studies revealed that the
initial rate of oxidation of both styrene and 1-octene were first order
dependent on catalyst concentration and substrates concentration
whereas independent of oxygen pressure. The variation in catalyst con-
centration, substrates concentration and oxygen pressure with the cor-
responding rate of oxidation is showing in Figs. 4–6.
Fig. 4. Rate dependence of catalyst concentration using catalyst trans(Cl)-
[Ru(bpy)(CO)2(Cl)2] in CH2Cl2–C2H5OH (6:4) mixed solvent at 50 ꢁC and at
4.48 ꢀ 103 KNm3 pressure of Oxygen.
4. Conclusion
3.4. Effect of solvent, temperature, acid and extra ligand
Trans (Cl)-2,20-bipyridinedicarbonyldichlororuthenium(II) complex
was found catalytically active towards the oxidation of a wide variety of
organic substrates. CH2Cl2–C2H5OH (6:4) concoction solvent was
considered to be the best solvent for these catalytic reactions. Tert-butyl
hydroperoxide was found better oxidant as compare to molecular oxy-
gen. Catalytic activities of Ru(II) complexes were found to increase up to
60 ꢁC under normal pressure condition. Recycling activity of Ru(II)-
Bipyridine was found almost unaltered even after 6–8 repeated cata-
lytic run.
The effect of solvent on the rate and nature of product was also inves-
tigated. DMF, DMSO, CH3CN, methanol, ethanol, benzene and dichloro-
methane were used for this purpose but the best catalytic activity was found
in CH2Cl2–C2H5OH (6:4) mixed solvent system. The catalytic activities of
Ru(II) complexes were found to increase up to 60 ꢁC under normal pressure
condition. Above 60 ꢁC the rate of oxidation was found to decrease with the
noticeable decomposition ofcomplexes. Tosee the effectof acid, the methyl
Fig. 5. Rate dependence of substrates concentration using catalyst in CH2Cl2–C2H5OH (6:4) mixed solvent at 50 ꢁC and at 4.48 ꢀ 103 KNm3 pressure of Oxygen.
4

V. Sharma et al.
Journal of the Indian Chemical Society 98 (2021) 100012
Fig. 6. Rate dependence of oxygen pressure using catalyst trans(Cl)-[Ru(bpy)(CO)2(Cl)2] in CH2Cl2–C2H5OH (6:4) mixed solvent at 50 ꢁC.
4.1. Mechanism
Kinetics and other experimental observations suggest a tentative
mechanism for the oxidation of 1- alkene in presence of dioxygen as
oxidant-mechanism-1.
5

V. Sharma et al.
Journal of the Indian Chemical Society 98 (2021) 100012
[23] Yang ZW, Kang QX, Lei ZQ. Oxidation of cyclohexene by dendritic PAMAMSA-
Mn(II) complexes. J. Mol. Catal. Chem. 2004;213:169.
Funding
[24] Allal BA, Firdoussi LE, Mortreux A. Catalytic oxidation of α-pinene by transition
Not applicable.
metal using t-butyl hydroperoxide and hydrogen peroxide. J. Mol. Catal. Chem.
2003;200:177.
[25] Cuervo LG, Kozlov YN, Shulpin GB. Oxidation of saturated hydrocarbons with
peroxyacetic acid catalyzed by vanadium complexes. J. Mol. Catal. Chem. 2004;
218:171.
Availability of data and material
[26] Validkar V, Tembe GL, Ravindranathan M, Rama HS. Catalytic oxidation of alkanes
and alkenes by polymer-anchored amino acid–ruthenium complexes. J. Mol. Catal.
Chem. 2004;223:31.
Presently Not (May be provided if required).
[27] Li JM, Meng XG, Hu CW, Du J, Zeng XC. Oxidation of 4-chlorophenol catalyzed by
Cu(II) complexes under mild conditions: kinetics and mechanism. J. Mol. Catal.
Chem. 2009;229:102.
Declaration of competing interest
[28] Khokhar MD, Shukla RS, Jasra RV. Selective oxidation of methane by molecular
oxygen catalyzed by a bridged binuclear ruthenium complex at moderate pressures
and ambient temperature. J. Mol. Catal. Chem. 2009;299:108.
[29] Chang CF, Liu ST. Catalytic oxidation of anilines into azoxybenzene on mesoporous
silicas containing cobalt oxide. J. Mol. Catal. Chem. 2009;299:121.
[30] Punniyamurthy T, Velusamy S, Iqbal J. Recent advances in transition metal
catalyzed oxidation of organic substrates with molecular oxygen. Chem. Rev. 2005;
105(6):2329.
Not applicable.
References
[1] Leising RA, Takeuchi KJ. Aerobic oxidation of cyclohexene with a phosphine-
ruthenium (II)-aquo catalyst. Inorg. Chem. 1987;26:4391.
[2] Goldstein AS, Beor RH. Catalytic oxidation of hydrocarbons with O2 or H2O2 using
a sterically hindered ruthenium complex. J. Am. Chem. Soc. 1994;116:2424.
[3] Xinrongs L, Tinyu X, Huizhang L. Studies on styrene oxidation reaction catalyzed by
ruthenium substituted polyoxotungstates: kinetics and phase transfer effect. J. Mol.
Catal. Chem. 2000;161:163.
[4] Kung Harold H. Studies in surface science and catalysis. Chapter11-Selective
oxidation reaction 1989;45:169–99.
[5] Erdmon D, Galvan YP. Mechanistic analysis of water oxidation catalyst cis-[Ru
(bpy)2(H2O)2]þ2: effect of dimerization. Catalysts 2017;7(2):39.
[6] Prengle HW, Barona N. Petrochemicals by liquid phase oxidation. Hydrocarb.
Process. 1970;49(31):106.
[7] Patterson WR, Pearce R. Catalysis in Chemical Processes. New York: Wiley; 1981.
p. 251.
[8] Engler T, Combrink K, Lefavie M. Stereospecific lewis acid-promoted reactions of
styrenyl systems with 2-alkoxy-(6-alkyl)-1,4-benzoquinones: scope, limitations, and
synthetic applications. J. Org. Chem. 1994;59:6567.
[9] Bodnar Z, Mallat T, Baiker A. Oxidation of 2,3,6-trimethylphenol to trimethyl-1,4-
benzoquinone with catalytic amount of CuCl2. J. Mol. Catal. Chem. 1996;110:55.
[10] Kuriacose JC. Catalysis. New Delhi: Rajkamal Electric Press; 1991. p. 168.
[11] Hayaish O. In: Hayaishi, editor. Oxygenases. New York: Academic Press; 1976. p. 1.
[12] Vaska L. Reversible activation of covalent molecules by transition-metal complexes:
the role of the covalent molecule. Acc. Chem. Res. 1976;9:175.
[13] Tashiro K, Kouno N, Wang H. Crystal structure of poly(lactic acid) stereocomplex:
random packing model of PDLA and PLLA chains as studied by X-ray diffraction
analysis. Macromolecules 2017;50(20):8048.
[14] He C, Ching J, Zang X. Recent advances in the catalytic oxidation of volatile organic
compounds: a review based on pollutant sorts and sources. Chem. Rev. 2019;
119(7):4471.
[15] Jones RD, Sommerville DA, Basolo F. Synthetic oxygen carriers related to biological
systems. Chem. Rev. 1979;79:139.
[16] Kim Y, Ahh S, Hwang JY. Dehydrogenative oxidation of alcohols catalyzed by
highly dispersed ruthenium incorporated titanium oxide. Catalysts 2017;7(1):7.
[17] Hiremath CV, Hiremath DC, Nandibeworn ST. Ruthenium(III) catalysed oxidation
of gabapentin (neurontin) by diperiodatonickelate(IV) in aqueous alkaline medium:
a kinetic and mechanistic study. J. Mol. Catal. Chem. 2007;269:246.
[18] Bffin BP, Charkson JP, Kundu A. Pd(II)-biquinoline catalyzed aerobic oxidation of
alcohols in water. J. Mol. Catal. Chem. 2005;225:111.
[19] Valodkar VB, Tembe GL, Rama HS. Catalytic oxidation of alkanes and alkenes by
polymer-anchored amino acid–ruthenium complexes. J. Mol. Catal. Chem. 2004;
223:31.
[31] Zhang C, Jiao N. Dioxygen activation under ambient conditions: Cu-catalyzed
oxidative amidation diketonization of terminal alkynes leading to
J. Am. Chem. Soc. 2010;132(1):28.
α-ketoamides.
[32] Podhajsky SM, S Sigman M. Coupling Pd-catalyzed alcohol oxidation to olefin
functionalization : hydrohalogenation/hydroalkoxylation of styrenes.
Organometallics 2007;26(33):5680.
[33] Gligorich KM, Cummimng SA. Palladium-catalyzed reductive coupling of styrenes
and organostannanes under aerobic conditions. J. Am. Chem. Soc. 2007;129(46):
14193.
[34] Urkalon KB, Sigman MS. Palladium-catalyzed hydroalkylation of styrenes with
organozinc reagents to form CarbonꢂCarbon sp3ꢂsp3 bonds under oxidative
conditions. J. Am. Chem. Soc. 2009;131(50):18042.
[35] Santra PK, Sagar P. Dihydrogen reduction of nitroaromatics, alkenes, alkynes using
Pd(II) complexes both in normal and high pressure conditions. J. Mol. Catal. Chem.
2003;197:37.
[36] Sagar P, Rani V. Dihydrogen reduction of nitroarmatics, alkenes, alkynes,
benzaldehyde and benzil by newly synthesized Rh(I) complexes in homogeneous
phase. Synth.Reac. Metallo.Org.Nano.Met.Chem. 2010;40:754.
[37] Sharma V, Sagar P. Catalytic oxidation of internal alkenes, terminal alkenes and
alcohols by Rh(I) complexes of S-triazene derivatives. Rasayan J. Chem. 2010;3:16.
[38] Sharma V, Sagar P. Highly active Rh(I) complexes used for the catalytic oxidation of
internal alkenes, terminal alkenes and alcohols. Orient. J. Chem. 2010;26:555.
[39] Sharma V, Sagar P, Kumar R. Efficient catalytic oxidation of internal alkenes,
aromatic hydrocarbons and alcohols by using orthometallated and non-
orthometallated. J.Ind.Chem. Soc. 2012;89:463.
[40] Shi F, Tse MK, Pohl MM, Radnik J. Nano-iron oxide-catalyzed selective oxidations
of alcohols and olefins with hydrogen peroxide. J. Mol. Catal. Chem. 2008;292:28.
[41] Zhang S, Zhao G, Gao S, Xi Z, Xu J. Secondary alcohols oxidation with hydrogen
peroxide catalyzed by [n-C16H33N(CH3)3]3PW12O40: transform-and-retransform
process between catalytic precursor and catalytic activity species. J. Mol. Catal.
Chem. 2008;289:22.
[42] Marta A, Andrade, D Luísa M, Martins RS. Sustainability in catalytic cyclohexane
oxidation: the contribution of porous support materials. Catalysts 2020;10(1):2.
[43] Chatterjee D. Mitra, Oxidation of organic substrates catalyzed by a novel mixed-
ligand ruthenium(III) complex. J. Mol. Catal. Chem. 2000;161:17.
[44] Maitlis PM. The palladium (II) induced oligomerization of acetylenes: an
organometallic detective story. Acc. Chem. Res. 1976;9:93.
[45] Page AL. Method of Soil Analysis Chemical and Microbiological Properties. second
ed. Modison, Wisconsin, USA: American Society of Agronomy Inc., Soil Science of
American Inc.; 1982.
[46] Singh AK, Katyal MS, Singh RP. Spectrophotometric determination of Os(VIII) &
Ru(III) with 4,5-Diamino-2-mercaptopyrimidin-6-ol. Ind. J. Chem., Sec.-A 1976;
14A:367.
[47] Noblat SC, Deronzier A, Ziessel R, Zsoldos D. Selective Synthesis and
electrochemical behavior of cis and trans Ruthenium bipyridine complexes.
Cmparative studies of their electrocatalytic activity toward thr reduction of carbon
dioxide. Inorg. Chem. 1997;36:5384.
[20] Li Z, Xia CG. Oxidation of hydrocarbons with iodobenzene diacetate catalyzed by
manganese(III) porphyrins in a room temperature ionic liquid. J. Mol. Catal. Chem.
2004;214:95.
[21] Hussian A, Shukla RS, Thorat RB, Bhatt KN. Ru(III) analogue of model methane
monooxygenase in the effective catalytic oxidation of cyclohexane by molecular
oxygen. J. Mol. Catal. Chem. 2003;193:1.
[22] Remias JE, Sen A. Palladium-mediated aerobic oxidation of organic substrates: the
role of metal versus hydrogen peroxide. J. Mol. Catal. Chem. 2002;189:33.
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