Vol.3, No.7, 542-550 (2011) Natural Science
Copyright © 2011 SciRes. OPEN ACCESS
Synthesis, spectral characterization, catalytic and
biological studies of new Ru(II) carbonyl Schiff base
complexes of active amines
Vellalapalayam Vangaiannan Raju1, Kugalur Palanisamy Balasubramanian1,
Chinnasamy Jayabalakrishnan2, Vaiapuri Chinnusamy2*
1Department of Chemistry, Gobi Arts & Science College, Gobichettipalayam, India;
2PG Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts & Science, Coimbatore, India;
*Corresponding Author: vchinnusamy@yahoo.com
Received 23 December, 2010; revised 22 March, 2011; accepted 10 April, 2011.
The synthesis and characterization of several
hexa–coordinated Ru(II) complexes of the type
[Ru(CO)(B)(L)] (B = PPh3/AsPh3/py/pip; L = di-
basic tetradentate ligand derived from the con-
densation of isatin with diamines) were reported.
IR, electronic, 1H-NMR, 31P-NMR of the com-
plexes are discussed. An octahedral geometry
has been tentatively proposed for all these
complexes. The new complexes have been
tested for the catalytic activity in the reaction of
oxidation of alcohols in the presence of N-me-
thylmorpholine-N-oxide as co-oxidant. The new
complexes were also exhibited antimicrobial
Keyw ords: Ruthenium(II) Complexes; Tetradentate
N2O2 Schiff Base; Characterization; Catalytic
Oxidation; Antimicrobial Activity
Transition metal complexes with tetradentate Schiff
base ligands have been studied as catalyst for a number
of organic oxidation and reduction reactions and electro
chemical reduction processes [1,2]. The accessibility of
ruthenium higher oxidation states [3,4] converts them
into excellent catalyst for redox reactions. Particularly,
metal complexes of ruthenium have demonstrated to be
useful laboratory and industrial homogeneous catalysts
in the epoxidation of alkenes and oxidation of alcohols
using iodosylbenzene, sodium hypochlorite hydrogen
peroxide and N-methylmorpholine-N-oxide as oxygen
sources [5-8]. Further the oxidation of organic substrates
mediated by high valent ruthenium-oxo species evokes
much interest in modeling of cytochrome p.450 [9].
Sharpless et al. [10] carried out a yield oriented study of
oxidation of cholesterol, geranial etc. catalyzed by ru-
thenium complexes in the presence of N-methylmor-
pholine-N-oxide and N, N-dimeth ylaniline-N-oxide. Fur-
thermore, the catalytic activities of ruthenium complexes
containing tertiaryphosphine or arsine ligands are well
established [11,12]. Tetradentate Schiff base complexes
have been employed as catalysts for many reactions and
as biological models in understanding the structure of
bio molecules and biological process [13,14].
In addition, the chemistry of chelating tetradentate
Schiff base ligands with ruthenium has also been exten-
sively studied [15]. This is due to the fact that Schiff
bases offer opportunities for inducing substrate chirality,
tuning metal centered electronic factors, enhancing solu-
bility and stability and their use as either homogeneous
or heterogeneous catalysis [16-18]. The oxidation of
primary and secondary alcohols into their corresponding
aldehydes and ketones respectively, plays a central role
in organic synthesis [19,20]. In continuation of our re-
search interest [21] to understand the role of these sim-
ple and inexpensive N2O2 donor Schiff base ligands to-
wards ruthenium, the reaction of Schiff bases derived
from isatin and diamines with ruthenium(II) precursors
containing PPh3/AsPh3/py/pip has been carried out. Thus,
the present work describes the results of synthesis, char-
acterization and properties of hexa coordinated Ru(II)
complexes exhibiting a N2O2 ligating core with their
catalytic activity towards oxidation of alcohols in the
presence of NMO. Further, the antibacterial activity of
the Schiff bases and their ruthenium complexes were
examined. The following Schiff bases, derived from the
condensation of isatin with ethylenediamine/o-phenyle-
nediamine/propylene diamine (Scheme 1), were used to
prepare the new ruthenium (II) complexes.
V. V. Raju et al. / Natural Science 3 (2011) 542-550
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Scheme 1. Keto-enol tautomerism.
2.1. Materials
The Schiff bases were prepared by the reported pro-
cedure [21,22]. All the reagents used were analytical
reagent grade. Solvents were purified and dried accord-
ing to standard procedures. RuCl3.3H2O, triphenylpho-
sphine, propylenediamine, ethylenediamine, o-phenyle-
nediamine and isatin were purchased from Loba Chemie
Pvt Ltd., Bombay, India and were used as such without
further purification. [RuHCl(CO)(PPh3)3] [23], [RuHCl
(CO)(B)(PPh3)2] [24] (where B = py/pip) and [RuHCl
(CO)(AsPh 3)3] [25] were prepared by reported literature
2.2. Physical Measurements
The analysis of C, H and N were performed on a
Carlo Erba 1160 model 240 Perkin Elmer CHN analyzer,
IR spectra were recorded in KBr pellets in the 4000 -
400 cm–1 region in a Jasco 400 plus spectrophotometer.
Electronic spectra were recorded in CH2Cl2 solution
with a Hitachi U – 3210 spectrophotometer in the range
of 800 - 200 nm. 1H-NMR and 31P-NMR spectra were
recorded on a Burker 400 MHz instrument using TMS as
an internal reference. Melting points were recorded with
Raaga apparatus and were uncorrected.
2.3. Synthesis of New Carbonyl Complexes
of RU(II)
To a solution of [RuHCl(CO)(EPh3)2(B)] [where E = P
or As; B = PPh3/py/pip/AsPh3] (0.1 g, 0.1 - 0.13 mmol)
in benzene (25 cm3),was added the appropriate Schiff
base (0.039 - 0.053 g, 0.1- 0.13 mmol). The solution was
heated under reflex for 6 hrs. Then, it was concentrated
to ca.3 cm3, cooled and new complexes were separated
upon addition of small quantity (6 cm3) of light petro-
leum (60 - 80˚C). The products were filtered, washed
with light petroleum, recrystalysed from CH2Cl2/light
petroleum mixture and dried in vacuo (yield: 65% -
70%). The purity of the complexes was checked by TLC.
2.4. Catalytic Oxidation
Catalytic oxidation of alcohols to the corresponding
carbonyl compounds by ruthenium(II) carbonyl Schiff
base complexes was studied in the presence of NMO as
co-oxidant by a typical reaction using the complex
[Ru(CO)(B)L] as catalyst, and the alcohol as substrate at
a 1:100 molar ratio. For this purpose, a solution of ru-
thenium complex (0.01 mmol) in 20 cm3 CH2Cl2 was
added to the solution of the substrate (1mmol) and NMO
(3 mmol) and the mixture was stirred for 3 - 7 hrs at
room temperature. The solvent was evaporated from the
mother liquor under reduced pressure and the residue
was then extracted with petroleum ether (60˚C - 80˚C).
2.5. Antibacterial Activity Studies
Pathogenic microbials namely Escherichia Coli, Aero-
monas hydrophila and Salmonella typhi were used to test
the biological potential of the isatin diimine and their
carbonyl complexes of ruthenium (II). The antibacterial
activities of the complexes were determined by disc dif-
fusion method [26]. The bacteria were cultured in nutri-
ent agar medium in petriplates and used inoculums for
the study. The complexes to be tested were dissolved in
DMSO to a final concentration of 0.25%, 0.5% and 1%
and soaked in filter paper disc of 5 mm diameter and of
1 mm thickness. The disc were placed on the previously
seeded plates and incubated at 35 ± 2˚C for 24 hrs. The
diameter of inhibitory zone around each disc was meas-
ured after 24 hrs. Streptomycin was used as a standard.
3.1. Analytical Studies
Complexes of general formula [Ru(CO)(B)(L)] (where
B = PPh3/AsPh3/py/pip; L= dibasic tetradentate Schiff
bases) were synthesized by the reactions of
[RuHCl(CO)(PPh3)3], [RuHCl(CO)(AsPh3)3] and
[RuHCl(CO)(PPh3)2(B)] (where B = py/pip) with the
respective tetradentate Schiff bases (Scheme 2) in a 1:1
molar ratio in benzene.
The analytical data for the new complexes agree well
with the proposed molecular formula as given in Table 1.
In all the reactions it has been observed that the Schiff
bases behave as a dibasic tetratentate ligands by substi-
tuting the chloride ion, hydride ion and two triphenyl-
phosphine/arsine groups from each mole of the starting
complexes to form the mono nuclear complexes. These
observations indicate a more labile nature for the Ru-P
bond compared to the Ru-N bond of the heterocyclic
nitrogen bases in these complexes. The difference in the
strength of Ru-P/As and Ru-N bonds may be explained
as due to the better σ donation ability of the nitrogen
bases compared to that of triphenylphosphine/ arsine.
The Schiff base ruthenium(II) complexes are highly col-
ored, stable to air and light and soluble in chloroform,
methylene chloride, benzene and DMSO.
3.2. I.R. Spectra
The most important IR bands are presented and as-
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signed in Table 2. The bands appearing at 1740 - 1715
cm–1 and 1652 - 1619 cm–1 in the ligand spectra were
assigned to stretching vibration modes of C = O and C =
N respectively. All the bands assigned to stretching vi-
bration modes in the free ligands changed in the spectra
of metal complexes. New bands recorded at 1599 -1583
cm–1 and 1637 - 1600 cm–1 vibration modes respectively
suggest the enolisation of the NH group of isatin and
coordination through the oxygen of the C-O group [21,
27]. The formation of the Ru-O and Ru-N bands is fur-
ther supported by the appearance of νM-O and νM-N band
in the regions 576 - 541 cm–1 and 492 - 475 cm–1 respec-
Scheme 2. Preparation of new Ru(II) Schiff base complexes.
Table 1. Analytical data of new Ru(II) complexes.
Complex Mp (˚C) Yield (%)
[Ru(CO)(PPh3)(L1)] 168 80 62.80(62.61) 3.81(3.76) 7.92(8.05)
[Ru(CO)(AsPh3)(L1)] 158 78 59.12(59.25) 3.59(3.67) 7.46(7.52)
[Ru(CO)(py)(L 1)] 143 75 54.95(55.37) 3.24(3.10) 13.35(12.50)
[Ru(CO)(pip)(L1)] 125 78 54.33(53.57) 4.34(4.01) 13.40(12.67)
[Ru(CO)(PPh3)(L2)] 172 75 63.24(64.61) 4.02(3.85) 7.77(7.21)
[Ru(CO)(AsPh3)(L2)] 160 80 59.61(62.01) 3.79(3.51) 7.32(6.56)
[Ru(CO)(py)(L 2)] 145 70 55.76(57.75) 3.53(3.87) 13.01(12.58)
[Ru(CO)(pip)(L2)] 130 78 55.15(55.75) 4.64(4.38) 12.86(11.96)
[Ru(CO)(PPh3)(L3)] 157 80 65.16(66.18) 3.58(3.85) 7.41(7.58)
[Ru(CO)(AsPh3)(L3)] 142 76 61.57(62.75) 3.38(3.15) 7.00(6.91)
[Ru(CO)(py)(L 3)] 137 75 58.74(59.62) 2.97(3.03) 12.24(11.56)
[Ru(CO)(pip)(L3)] 125 75 58.13(57.67) 3.98(3.87) 12.11(11.91)
Table 2. IR and UV - Visible Spectral data for the ligands and new Ru(II) complexes.
Complex ν(C = N) ν(C = O) ν(C - O) ν(M - N) ν(M - O) λmax
HL1 1619 1720 -
[Ru(CO)(PPh3)(L1)] 1620 - 1585 475 541 246, 320, 360, 600
[Ru(CO)(AsPh3)(L1)] 1628 - 1583 480 547 250, 320, 362,590
[Ru(CO)(py)(L 1)] 1600 - 1590 482 562 248, 316, 368, 593
[Ru(CO)(pip)(L1)] 1637 - 1583 488 576 246, 315, 368, 598
HL2 1652 1715 -
[Ru(CO)(PPh3)(L2)] 1636 - 1589 487 560 246, 315, 568
[Ru(CO)(AsPh3)(L2)] 1622 - 1597 490 570 248, 368, 408
[Ru(CO)(py)(L 2)] 1628 - 1599 492 575 248, 316, 463, 590
[Ru(CO)(pip)(L2)] 1630 - 1585 479 547 250, 350, 403
HL3 1630 1740 -
[Ru(CO)(PPh3)(L3)] 1607 - 1587 476 550 248, 318, 550
[Ru(CO)(AsPh3)(L3)] 1615 - 1592 490 570 248, 325, 563
[Ru(CO)(py)(L 3)] 1603 - 1590 486 568 246, 313, 569, 600
[Ru(CO)(pip)(L3)] 1600 - 1588 482 571 246, 320, 350, 596
V. V. Raju et al. / Natural Science 3 (2011) 542-550
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tively in the spectra of the chelates [21,28,29]. The most
important conclusion drawn from the infrared spectral
evidence is that the diamine bis(isatin) Schiff base ligand
is acting as chelating agent towards the central metal ion
as dibasic ONNO tetradentate ligand, via the two coor-
dinating sites of nitrogen atoms and two negatively
charged oxygen atoms of isatin residues forming five-
membered chelating rings [30]. In addition, other char-
acteristic bands due to PPh3 and AsPh3 are also present
around 1438 cm–1 [31], in the spectra of Schiff base
complexes. A medium intensity band is observed in the
1020 cm–1 region, characteristics of the coordinated
pyridine or piperidine [21,32]. In all the ruthenium com-
plexes the band due to terminally coordinated C O
group appeared at 1900 - 1944 cm–1 [33].
3.3. Electronic Spectra
The electronic spectra of all the complexes in dichlo-
romethane showed three to four bands in the region 246
- 600 nm. All the Schiff base ruthenium complexes are
diamagnetic, indicating the presence of ruthenium in the
+2 oxidation state. The ground state of ruthenium(II) in
an octahedral environment is 1A1g from the t6
2g configu-
ration and excited states corresponding to the t5
2g e1
configurations are 3T1g, 3T2g, 1T1g and 1T2g. Hence four
bands corresponding to the transition 1A1g 3T1g, 1A1g
3T2g, 1A1g 3T1g and 1A1g 1T2g are possible in the
order of increasing energy. The bands around 600 - 550
nm and 463 - 403 nm are assigned to 1A1g 1T1g [34,35]
and the charge transfer reactions respectively are listed
in Table 2. The charge transfer bands observed in all the
complexes due to M L transitions are possible in the
visible region [36-38]. Moreover the presence of car-
bonyl, triphenylphosphine/arsine and heterocyclic bases
as ligands, which are capable of producing strong ligand
field in eg
* which is relatively higher energy levels. This
band has been assigned to the charge-transfer transition
arising from the excitation of an electron from the metal
t2g level to the unfilled molecular orbital’s derived from
the eg
* level of the ligands should appear in the relatively
high energy region compared to those due to t2g e
transitions [34-36]. The other high energy bands have
been designated as π-π* and n-π* transitions for the elec-
trons localized on the azomethine group of Schiff bases
[32]. The pattern of the electronic spectra of all the com-
plexes indicated the presence of an octahedral environ-
ment around the ruthenium(II) ion, similar to that of
other octahedral ruthenium(II) complexes [37].
3.4. 1H-NMR Spectra
The 1H NMR spectra of some complexes were re-
corded to confirm the bonding of the Schiff base to the
ruthenium ion and given in the Table 3. Multiplets are
observed around 7.2 - 7.8 ppm in all the complexes and
have been assigned to the aromatic protons of triphenyl-
phophine, triphenylarsine, pyridine, piperidine and isatin
Schiff base ligands [29]. A singlet appears in the region
1.36 - 1.4 ppm for the methylene protons [39]. In the
complexes [Ru(CO)(PPh3)(L3)] and [Ru(CO)(AsPh3)(L3)]
an extra singlet was found in the region at 2.05 ppm,
which has been assigned to the extra methylene group
present in the Schiff base. The 1H NMR spectra of the
neutral diamagnetic chelates of the type [Ru(CO)(B)(L)]
are similar to those of the ligands, excepting that the
signal due to NH proton of isatin disappears. This proves
the deprotonation of NH group upon complexation and
supports the above NMR spectral data suggesting that
the ligand acts as dibasic tetra dentate chelating agent.
3.5. 31P-NMR Spectra
The 31P-NMR spectra for a few of the complexes have
been recorded in order to confirm the presence of
triphenylphosphine group and to determine the geometry
of the complexes (Table 3). The appearance of singlet
at 28.78, 28.75 and 28.70 ppm for the complexes
[Ru(CO)(PPh3)(L1)], [Ru(CO)(PPh3)(L2)] and
[Ru(CO)(PPh3)(L3)] respectively indicates the presence
of one triphenylphosphine group in these complexes.
3.6. Catalytic Activity of the Complexes
Catalytic oxidation of primary alcohols and secondary
alcohols by the synthesized ruthenium(II) carbonyl
Schiff base complex [Ru(CO)(B)(L)]was carried out in
CH2Cl2 in the presence of NMO. Results of the present
investigation suggest that the complex is able to react
efficiently with NMO to yield a high valent ruthenium-
oxo species [15,40] capable of transferring oxygen atom
to alcohols. The oxidation of benzylalcohol to benzal-
dehyde resulted in 89% yield. Further, the complex ef-
fectively catalyzes the oxidation of aliphatic alcohols
such as butane-2-ol, to the corresponding ketones effec-
tively and is evident from Table 4. Moreover, the com-
plex effectively catalyzes the oxidation of five and six
membered cyclic alcohols to the corresponding ketones
with the conversion rates to the extent of 90% and 82%
respectively. The reaction provides a new environment
friendly route to the conversion of alcoholic functions to
carbonyl group and water is the only byproduct during
the course of the reaction. It has been concluded that the
complexes have a better catalytic efficiency in the case
of oxidation of primary and secondary alcohols in the
presence of NMO.
3.7. Antibacterial Studies
The in vitro antibacterial screening of the ligands and
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Table 3. NMR Spectral data of new Ru(II) complexes.
S. No. Complex 1H-NMR data (ppm) 31P-NMR data (ppm)
1. [Ru(CO)(PPh3)(L1)] 7.2 - 7.6 (Ph, m),1.36 (N-(CH2)2, s) 28.78
2. [Ru(CO)(AsPh3)(L1)] 7.3 - 7.6 (Ph, m),1.36 (N-(CH2)2, s) -
3. [Ru(CO)(py)(L1)] 7.2 - 7.6 (Ph, m),1.4 (N-(CH2)2, s) -
4. [Ru(CO)(PPh3)(L2)] 7.3 - 7.8 (Ph, m) 28.75
5. [Ru(CO)(AsPh3)(L2)] 7.2 - 7.7 (Ph, m) -
6. [Ru(CO)(pip)(L2)] 7.2 - 7.6 (Ph, m) -
7. [Ru(CO)(PPh3)(L3)] 7.3 - 7.6 (Ph, m),1.36 (N-(CH2)2, s), 2.05 (CH2,s)28.70
8. [Ru(CO)(AsPh3)(L3)] 7.2 - 7.6 (Ph, m),1.36 (N-(CH2)2, s), 2.05 (CH2,s)-
Table 4. Catalytic oxidation of alcohols by Ru(II) complexes.
Complex Substrate Product Yielda Turnoverb
Benzylalcohol Benzaldehyde 76 75
Cyclohexanol Cyclohexanone 82 80
Butane-2-ol Butanone 84 88
Cyclopentanol Cyclopentanone 90 92
Benzylalcohol Benzaldehyde 80 81
Cyclohexanol Cyclohexanone 82 80
Butane-2-ol Butanone 73 78
Cyclopentanol Cyclopentanone 89 88
Benzylalcohol Benzaldehyde 76 78
[Ru(CO)(py)(L 1)]
Cyclohexanol Cyclohexanone 83 86
Butane-2-ol Butanone 74 79
Cyclopentanol Cyclopentanone 90 92
Benzylalcohol Benzaldehyde 77 79
Cyclohexanol Cyclohexanone 85 87
Butane-2-ol Butanone 80 84
Cyclopentanol Cyclopentanone 91 95
Benzylalcohol Benzaldehyde 81 85
Cyclohexanol Cyclohexanone 80 83
Butane-2-ol Butanone 78 87
Cyclopentanol Cyclopentanone 90 91
Benzylalcohol Benzaldehyde 82 81
Cyclohexanol Cyclohexanone 81 85
Butane-2-ol Butanone 72 76
Cyclopentanol Cyclopentanone 89 86
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Benzylalcohol Benzaldehyde 82 84
[Ru(CO)(py)(L 2)]
Cyclohexanol Cyclohexanone 80 84
Butane-2-ol Butanone 71 74
Cyclopentanol Cyclopentanone 90 87
Benzylalcohol Benzaldehyde 76 79
Cyclohexanol Cyclohexanone 83 78
Butane-2-ol Butanone 72 75
Cyclopentanol Cyclopentanone 90 93
Benzylalcohol Benzaldehyde 75 78
Cyclohexanol Cyclohexanone 86 82
Butane-2-ol Butanone 76 80
Cyclopentanol Cyclopentanone 93 90
[Ru(CO)(AsPh3)(L3)] Benzylalcohol Benzaldehyde 73 77
Cyclohexanol Cyclohexanone 79 80
Butane-2-ol Butanone 70 73
Cyclopentanol Cyclopentanone 91 86
[Ru(CO)(py)(L 3)] Benzylalcohol Benzaldehyde 75 78
Cyclohexanol Cyclohexanone 75 79
Butane-2-ol Butanone 72 75
Cyclopentanol Cyclopentanone 93 80
[Ru(CO)(pip)(L3)] Benzylalcohol Benzaldehyde 67 70
Cyclohexanol Cyclohexanone 81 80
Butane-2-ol Butanone 78 81
Cyclopentanol Cyclopentanone 91 86
their ruthenium complexes have been carried out against
Escherichia Coli, Aeromonas hydrophila and Salmonella
typhi using a nutrient agar medium by disc diffusion
method. The results (Table 5) showed the complexes
exhibit moderate activity against Escherichia Coli, Aero-
monas hydrophila and Salmonella typhi. The toxicity of
ruthenium chelates increases on increasing the concen-
tration [41]. The increase in the antibacterial activity of
metal chelates may be due to the effect of the metal ion
on the normal cell process. A possible mode of the toxic-
ity increase may be considered in light of Tweeds chela-
tion theory [42]. Chelation considerably reduces the po-
larity of the metal ion because of partial sharing of its
positive charge with the donor groups and possible π-
electron delocalization over the whole chelate ring. Such
chelation could enhance the lipophilic character of the
central metal atom, which subsequently favors its per-
meation through the lipid layers of cell membrane. Fur-
thermore, the mode of action of the compounds may
involve in the formation of a hydrogen bond through the
azomethine (>C = N) group with the active centers of
cell constituents, resulting in interference with the nor-
mal cell processes [42]. Though the complexes possess
activity, it could not reach the effectiveness of the stan-
dard drug streptomycin. The variation in the effective-
ness of the different compounds against different organ-
isms depend either on the impermeability of the cells of
the microbes or differences in ribosomes of microbial
cells [40,41].
Based on the analytical, spectral (IR, electronic, 1H
NMR and 31P-NMR) data, Scheme 3 octahedral stru-
cture has been tentatively proposed for all the new car-
bonyl Schiff base complexes of ruthenium (II).
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Table 5. Antibacterial activity of ligands and Ru(II) complexes (diameter of inhibition zones-mm).
Escherichia coli Aeromonas hydrophila Salmonella typhi
0.25% 0.5% 1.0%0.25% 0.5%1.0% 0.25% 0.5%1.0%
L1 10 11 13 11 12 13 9 12 13
[Ru(CO)(PPh3)(L1)] 12 14 16 14 17 18 13 16 20
[Ru(CO)(AsPh3)(L1)] 11 15 17 12 16 20 14 17 21
[Ru(CO)(py)(L 1)] 14 16 20 13 17 19 15 17 20
[Ru(CO)(pip)(L1)] 16 18 20 13 17 19 15 18 20
L2 10 12 14 9 12 15 10 11 14
[Ru(CO)(PPh3)(L2)] 12 15 19 11 16 18 12 18 20
[Ru(CO)(AsPh3)(L2)] 15 18 21 12 18 21 14 15 18
[Ru(CO)(py)(L 2)] 14 16 19 14 19 20 18 20 21
[Ru(CO)(pip)(L2)] 15 20 21 16 18 21 19 20 21
L3 10 11 13 12 14 15 10 11 14
[Ru(CO)(PPh3)(L3)] 12 14 17 14 16 18 15 18 20
[Ru(CO)(AsPh3)(L3)] 14 18 20 15 18 20 17 18 21
[Ru(CO)(py)(L 3)] 16 17 21 14 17 19 19 22 23
[Ru(CO)(pip)(L3)] 17 18 22 16 18 22 17 19 22
Streptomycin 22 23 28 21 37 29 29 21 25
Scheme 3. Structure of New Ru(II) complexes.
A new family of carbonyl complexes of ruthenium(II)
containing N2O2 donor Schiff bases incorporating tri-
phenylphosphine/triphenylarsine/pyridine/piperidine li-
gands were synthesized and characterized. The new com-
plexes were tested as a new and efficient catalyst for the
oxidation of primary and secondary alcohols to their
corresponding aldehydes and ketones with excellent yields
in the presence of N-methylmorpholine-N-oxide. Further
the possible explanations for the mode of action of these
complexes against three different microbes are described.
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