Hydrolytic cleavage of Schiff bases by [RuCl2(DMSO)4]

Article abstract of DOI:10.1016/j.poly.2007.05.055

New hexa-coordinated Ru(II) complexes of the type [RuCl₂(DMSO)₂(diamine)] (diamine = o-phenylenediamine and ethylenediamine) have been prepared by reacting cis-[RuCl₂(DMSO)₄] with Schiff bases (H₂sal-en, 1; H₂nap-en, 2; H₂sal-o-pdn, 3; H₂nap-o-pdn, 4) in a 1:1 ratio. The ligands, which were expected to act as tetradentate (N₂O₂) chelates under the normal reaction conditions, were found to undergo hydrolytic cleavage to form the diamine and the corresponding aldehyde. All the complexes have been characterized by analytical and spectroscopic (IR, electronic and¹H NMR) data. Single-crystal X-ray analysis of the complex [RuCl₂(DMSO)₂(o-pndn)] revealed that the coordination environment around the ruthenium metal consists of a N₂S₂Cl₂ octahedron.

Full text of DOI:10.1016/j.poly.2007.05.055

Polyhedron 26 (2007) 4314–4320
www.elsevier.com/locate/poly
Hydrolytic cleavage of Schiff bases by [RuCl2(DMSO)4]
a
b
b
Duraiswamy Sukanya , Michael R. Evans , Matthias Zeller ,
a,
*
Karuppannan Natarajan
a
Department of Chemistry, Bharathiar University, Coimbatore 641 046, India
Department of Chemistry, Youngstown State University, 1 University Plaza, Youngstown, OH 44555-3663, USA
b
Received 12 February 2007; accepted 15 May 2007
Available online 16 June 2007
Abstract
New hexa-coordinated Ru(II) complexes of the type [RuCl2(DMSO)2(diamine)] (diamine = o-phenylenediamine and ethylenedi-
amine) have been prepared by reacting cis-[RuCl2(DMSO)4] with Schiff bases (H2sal-en, 1; H2nap-en, 2; H2sal-o-pdn, 3; H2nap-o-pdn,
4) in a 1:1 ratio. The ligands, which were expected to act as tetradentate (N2O2) chelates under the normal reaction conditions, were
found to undergo hydrolytic cleavage to form the diamine and the corresponding aldehyde. All the complexes have been characterized
by analytical and spectroscopic (IR, electronic and1H NMR) data. Single-crystal X-ray analysis of the complex [RuCl2(DMSO)2-
(o-pndn)] revealed that the coordination environment around the ruthenium metal consists of a N2S2Cl2 octahedron.
ꢀ 2007 Elsevier Ltd. All rights reserved.
Keywords: Ruthenium(II) complexes; Schiff bases; Dimethylsulfoxide; Hydrolytic cleavage; Crystal structure; NMR; Antimicrobial activity
1. Introduction
properties have been studied intensively [19–25]. On this
basis, we tried synthesizing some new ruthenium Schiff base
(N2O2) complexes containing dimethyl sulfoxide (O or S
donor), expecting them to have good biological activity.
The Schiff bases 1, 2, 3 and 4 (obtained by condensing a
diamine with 2-hydroxy-1-aldehydes), when treated with
[RuCl2(DMSO)4] in a 1:1 mole ratio in ethanol, surpris-
ingly yielded new ruthenium complexes which contain only
the diamine instead of the Schiff base. The complexes thus
obtained were also synthesized by the direct reaction of the
corresponding diamine and [RuCl2(DMSO)4]. The cleav-
age of the –C@N group of the Schiff base had occurred
and the diamine and aldehyde were regenerated. The dia-
mine formed reacted with [RuCl2(DMSO)4] to give com-
plexes of the type [RuCl2(DMSO)2(diamine)], and the
corresponding aldehydes were obtained in quantitative
yield. The new complexes were tested for their antimicro-
bial activity, owing to their water soluble nature and rich
donor atoms. The Schiff bases used in the present work
are given below.
Schiff bases are a special class of ligands with a vari-
ety of donor atoms exhibiting interesting coordination
modes towards various metals [1–5]. Metal Schiff base
complexes have been well known for their easy synthesis,
stability and wide application [6–10]. Rarely, in certain
cases hydrolytic cleavage of the Schiff base ligands
occurs. The –C@N– cleavage has been reported to occur
on a number of metal sites ranging from simple salts to
mixed ligand complexes [11–15], where the solvent sys-
tem, co-ligands and reaction conditions play an exuber-
ant role [16–18].
A large number of ruthenium Schiff base complexes
have been reported so far, and their catalytic and biological
*
Corresponding author. Tel.: +91 422 2424655; fax: +91 422 2422387.
E-mail address: k_natraj6@yahoo.com (K. Natarajan).
0277-5387/$ - see front matter ꢀ 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2007.05.055

D. Sukanya et al. / Polyhedron 26 (2007) 4314–4320
4315
The crystal data and refinement parameters are summa-
rized in Table 1.
HO
OH
HO
OH
X
2.4. Synthesis of the new Ru(II) complexes
X
All the new mononuclear ruthenium(II) complexes were
prepared by the following general procedure. An ethanolic
solution of cis-[RuCl2(DMSO)4] and the appropriate
ligand in a 1:1 mole ratio was heated under reflux for
4 h. The solution was filtered and left for slow evaporation.
The crystalline product that separated out was filtered off,
washed with ethanol and dried under vacuum. The filtrate
along with the ethanol washings were evaporated to dry-
ness. The aldehyde formed was extracted with petroleum
ether and then quantified. The individual syntheses are
given below.
HC
N
N
CH
HC
N
N
CH
X=
or
H2sal-en, 1;
H2nap-en, 2;
H2nap-o-pndn, 4
H2sal-o-pndn, 3;
[RuCl2(DMSO)2(o-pndn)] (5) was prepared from cis-
[RuCl2(DMSO)4] (0.100 g, 0.2 mmol) and H2sal-o-pndn
(0.062 g, 0.2 mmol) as dark red brown crystals. Yield:
80%. Anal. Calc. for RuC10H20N2O2Cl2S2: C, 27.52; H,
4.60; N, 6.4; S, 14.69. Found: C, 27.44; H, 4.39; N, 6.61;
S, 14.11%. IR: 3280, 3269, 1557, 1072, 1129 cmÀ1. UV
2. Experimental
2.1. Materials
All chemicals used were of Analar grade and solvents
were dried following the literature procedure [26]. cis-
[RuCl2(DMSO)4] and the ligands (H2sal-en, 1; H2nap-en,
2; H2sal-o-pndn, 3; H2nap-o-pndn, 4) were prepared as
reported earlier [27,28].
kmax: 248, 289. M.p.: >200 ꢁC (dec.).
Table 1
Crystal data and structure refinement parameters for [RuCl2(DMSO)2-
(o-pndn)]
Empirical formula
Formula weight
Temperature (K)
C10H20Cl2N2O2RuS2
436.37
100(2)
2.2. Physical methods
˚
Wavelength (A)
0.71073
monoclinic
P21/n
Infrared spectra of the ligand and the complexes have
been recorded on a Nicolet Avatar model FT-IR spectro-
Crystal system
Space group
Unit cell dimensions
photometer using KBr discs in the range 4000–400 cmÀ1
.
˚
Electronic spectra were recorded on a Systronics 119
UV–Vis spectrophotometer using methanol as the solvent.
Elemental analyses were performed with a Vario EL III
Elementar analyzer. H NMR spectra were recorded on
an AMX 400 instrument in DMSO solvent. Melting points
were recorded with a Lab India apparatus.
a (A)
12.5947(8)
8.1650(5)
15.4946(9)
90
98.4880(10)
90
1575.95(17)
4
1.839
1.597
˚
b (A)
˚
c (A)
1
a (ꢁ)
b (ꢁ)
c (ꢁ)
3
˚
Volume (A )
Z
Dcalc (Mg/m3)
Absorption coefficient (mmÀ1
F(000)
2.3. X-ray crystallography
)
880
Single crystals of [RuCl2(DMSO)2(o-pndn)] suitable for
X-ray diffraction studies were obtained from slow evapora-
tion of an ethanolic solution of the complex. Diffraction
data were collected on a Bruker AXS SMART APEX
CCD diffractometer at 100(2) K using monochromatic
Mo Ka radiation with the omega scan technique. The unit
cell was determined using SMART and SAINT+ [29]. The
structure was solved by direct methods and refined by
full-matrix least-squares against F2 with all reflections
using SHELXTL [30]. Refinement of an extinction coefficient
was found to be insignificant. All non-hydrogen atoms
were refined anisotropically. All hydrogen atoms were
placed in calculated positions and were refined with an iso-
tropic displacement parameter of 1.5 (CH3) or 1.2 (all oth-
ers) times that of the adjacent carbon or nitrogen atom.
Crystal size (mm)
h Range for data collection (ꢁ)
0.68 · 0.37 · 0.27
1.95–28.28
Limiting indices
À16 6 h 6 16,
À10 6 k 6 10,
À20 6 l 6 20
15551/3899 (0.0209)
99.8
Reflections collected/unique (Rint
Completeness to h = 28.28ꢁ (%)
Absorption correction
Maximum and minimum transmission
Refinement method
)
multi-scan
0.650 and 0.446
full-matrix least-squares on
F2
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I > 2r(I)]
R indices (all data)
3899/0/176
1.191
R1 = 0.0211, wR2 = 0.0522
R1 = 0.0212, wR2 = 0.0524
1.240 and À0.600
Largest difference in peak and hole
À3
˚
(e A
)

4316
D. Sukanya et al. / Polyhedron 26 (2007) 4314–4320
[RuCl2(DMSO)2(o-pndn)] (5) was also prepared from
dissolved in dimethyl sulfoxide to a final concentration of
0.25%, 0.5%, 0.75%, 1% and 1.5% and soaked in sterile
discs (7 mm diameter). These discs were placed on the
already seeded plates and incubated at 37 ꢁC for 24 h. After
incubation, the diameter (mm) of the inhibition zone
around each disc was measured and classified as resistant
(>15 mm), intermediate (13–14 mm) and sensitive
(<13 mm) (Hi-media). A clear zone around the disc indi-
cated the inhibitory activity of the compound on the organ-
ism. The data are presented in Table 4.
cis-[RuCl2(DMSO)4] (0.100 g, 0.2 mmol) and H2nap-o-
pndn (0.082 g, 0.2 mmol) as dark red brown crystals. Yield:
80%. Anal. Calc. for RuC10H20N2O2Cl2S2: C, 27.52; H,
4.60; N, 6.4; S, 14.69. Found: C, 27.03; H, 4.40; N, 6.14;
S, 14.77%. IR: 3282, 3269, 1555, 1072, 1129 cmÀ1. UV
k
max: 248, 289 (nm). M.p.: >200 ꢁC (dec.).
[RuCl2(DMSO)2(en)] (6) was prepared from cis-
[RuCl2(DMSO)4] (0.100 g, 0.2 mmol) and H2sal-en
(0.053 g, 0.2 mmol) as dark green crystals. Yield: 85%.
Anal. Calc. for RuC6H20N2O2Cl2S2: C, 18.55; H, 5.19; N,
7.20; S, 16.51. Found: C, 18.22; H, 5.04; N, 7.21; S,
3. Results and discussion
16.57%. IR: 3263, 3220, 1558, 1070, 1130 cmÀ1. UV kmax
270, 258. M.p.: >200 ꢁC (dec.).
:
New hexa-coordinated Ru(II) complexes of the type
[RuCl2(DMSO)2(diamine)] (diamine = o-phenylenedi-
amine and ethylenediamine) have been prepared by react-
ing cis-[RuCl2(DMSO)4] with the appropriate Schiff bases
(H2sal-en, 1; H2nap-en, 2; H2sal-o-pndn, 3; H2nap-o-pndn,
4) in a 1:1 ratio. The ligands, which were expected to act as
tetradentate (N2O2) chelates under the normal reaction
conditions, were found to undergo hydrolytic cleavage to
form the diamine and the corresponding aldehyde. The
diamine formed reacted with [RuCl2(DMSO)4] to give
complexes of the type [RuCl2(DMSO)2(diamine)], while
the corresponding aldehydes were isolated in quantitative
yield. The reaction scheme for one of the Schiff bases is
given below and the other Schiff bases were found to follow
the same route (see Scheme 1).
[RuCl2(DMSO)2(en)] (6) was also prepared from cis-
[RuCl2(DMSO)4] (0.100 g, 0.2 mmol) and H2nap-en
(0.073 g, 0.2 mmol) as dark green crystals. Yield: 85%.
Anal. Calc. for RuC6H20N2O2Cl2S2: C, 18.55; H, 5.19; N,
7.20; S, 16.51. Found: C, 18.29; H, 5.08; N, 7.23; S,
16.37%. IR: 3265, 3216, 1553, 1073, 1127 cmÀ1. UV kmax
270, 258. M.p.: >200 ꢁC (dec.).
:
We were also able to synthesize compounds 5 and 6, by
refluxing an ethanolic solution of cis-[RuCl2(DMSO)4] and
the corresponding diamine in a 1:1 mole ratio.
2.5. Antimicrobial activity
The new complexes have been tested in vitro to assess
their growth inhibitory activity against the pathogenic bac-
teria Aeromonas hydrophila, Eschericia coli, Salmonella
typhi, Streptococcus faecalis, Klebsiella pneumonia, Staphy-
lococcus aureus and Proteus mirabilis by the disc diffusion
method (Kirby–Bauer method) [31]. The bacteria were cul-
tured in nutrient broth medium and used as inoculum for
this study. Bacterial cells were swabbed on the surface of
Mueller Hinton Agar medium [prepared from NaCl (5 g),
peptone (5 g), beef extract powder (3 g), yeast extract pow-
der (3 g) and agar (20 g) in 100 mL distilled water; pH
7.3 0.2] in Petri plates. The compounds to be tested were
3.1. Elemental analysis
The analytical data obtained for the new Ru(II) com-
plexes were entirely different from the one calculated for
the expected hexa-coordinate Ru(II) complex contain-
ing the tetradentate dibasic ligand and dimethylsulfoxide.
The analytical data conform to the stoichiometry of the
new ruthenium complexes as [RuCl2(DMSO)2(diamine)].
The complexes obtained from H2sal-en (1) and H2nap-en
(2) were identical and their analytical data were also
Cl
DMSO
H2
DMSO
Cl
Cl
DMSO
OH
HO
N
HO
Ethanol, Reflux, 4h
Ru
Cl
+
Ru
+
HC
N
N
CH
CH
O
DMSO
N
DMSO
H2
DMSO
DMSO
O
O
N
Ethanol, Reflux, 4h
Ru
CH
HC
N
DMSO
Scheme 1.

D. Sukanya et al. / Polyhedron 26 (2007) 4314–4320
4317
the same as that corresponding to [RuCl2(DMSO)2(ethy-
lenediamine)]. Similarly, the complexes obtained from
H2sal-o-pdn (3) and H2nap-o-pdn (4) were identical and
their analytical data were also the same as that corre-
sponding to [RuCl2(DMSO)2(o-phenylenediamine)].
3.2. Infrared spectroscopy
The IR spectra of the free ligands showed a strong band
in the region 1642–1614 cmÀ1 assignable to m–C@N [32].
This band disappeared completely in the new complexes
indicating the absence of any –C@N group, because if
coordination of the ligand has occurred through the
azomethine nitrogen then this band will undergo a batho-
chromic shift of 40–10 cmÀ1 [33] and not completely disap-
pear. A new band around 1557 cmÀ1 (absent in the starting
complex) appeared in the new complexes, indicating the
presence of an aromatic –C@C– group [34]. Two new
bands in the region 3280 and 3215 cmÀ1, assignable to
Fig. 1. ORTEP diagram of [RuCl2(DMSO)2(o-pndn)].
Table 2
˚
Selected bond lengths (A) and bond angles (ꢁ) for [RuCl2(DMSO)2(o-
pndn)]
m
N–H, indicate the introduction of the –NH2 group (absent
˚
Bond lengths (A)
in the ligand and the starting complex) [35]. Two bands in
the region 1120 and 1070 cmÀ1 due to mS@O, characteristic
of S-bonded DMSO, are present while the absence of a
band around 935 cmÀ1 (due to O-bonded S@O) indicates
elimination of O-bonded DMSO [27].
Ru(1)–S(1)
Ru(1)–S(2)
Ru(1)–Cl(1)
Ru(1)–Cl(2)
Ru(1)–N(1)
Ru(1)–N(2)
2.2469(4)
2.2322(4)
2.4102(4)
2.4008(4)
2.1177(14)
2.1436(14)
1
3.3. H NMR spectroscopy
Bond angles (ꢁ)
N(1)–Ru(1)–N(2)
N(1)–Ru(1)–S(2)
N(2)–Ru(1)–S(2)
N(1)–Ru(1)–S(1)
N(2)–Ru(1)–S(1)
S(2)–Ru(1)–S(1)
N(1)–Ru(1)–Cl(2)
N(2)–Ru(1)–Cl(2)
S(2)–Ru(1)–Cl(2)
S(1)–Ru(1)–Cl(2)
N(1)–Ru(1)–Cl(1)
N(2)–Ru(1)–Cl(1)
S(2)–Ru(1)–Cl(1)
S(1)–Ru(1)–Cl(1)
Cl(2)–Ru(1)–Cl(1)
80.98(5)
88.22(4)
168.91(4)
176.95(4)
97.45(4)
93.450(15)
87.05(4)
86.49(4)
1
The H NMR spectral data for complex 5 showed two
signals at d 7.2 ppm (m, 2H) and d 7.41 ppm (t, 2H) that
were assigned to the aromatic protons from o-phenylenedi-
amine. A peak at d 6.5 ppm (s, 4H) is due to the two NH2
groups present in o-phenylenediamine. A sharp signal at d
3.22 ppm (s, 12H) due to the –CH3 group of S-bonded
dimethylsulfoxide was also found [27]. The 1H NMR spec-
tral data for complex 6 showed no signals around d 7 ppm
indicating the absence of aromatic protons. A peak at d
6.5 ppm (s, 4H) is due to the two NH2 groups present in
ethylenediamine. A sharp signal at d 3.22 ppm (s, 12H)
due to the –CH3 group of S-bonded dimethylsulfoxide
was also found.
90.481(15)
95.483(15)
85.81(4)
86.50(4)
95.260(15)
91.495(15)
170.686(15)
Table 3
3.4. Crystal structure of [RuCl2(DMSO)2 (o-pndn)]
˚
Hydrogen bonds for [RuCl2(DMSO)2(o-pndn)] (A and ꢁ)
D–HÁ Á ÁA
d(D–H)
(A)
d(HÁ Á ÁA)
d(DÁ Á ÁA)
\(DHA)
(ꢁ)
The ORTEP diagram of [RuCl2(DMSO)2(o-pndn)] is
shown in Fig. 1. Selected bond lengths and bond angles
are given in Table 2 and details of hydrogen bonding in
Table 3. The coordination environment around the ruthe-
nium metal consists of an N2S2Cl2 octahedron. The planar
diamine ligand occupies the equatorial position along with
two S-bonded dimethylsulfoxide groups, while the two
chlorine atoms occupy the axial positions. The chlorine
atoms, which were originally present in a cis position,
now occupies a trans position, as evident from the Cl(2)–
Ru(1)–Cl(1) bond angle of 170.686(15)ꢁ. Moreover the
two chlorine atoms are bent away from the two dimethyl-
˚
˚
˚
(A)
(A)
N(1)–
0.92
0.92
2.86
2.50
3.7092(15)
3.3285(15)
154.5
H(1A)Á Á ÁCl(1)#1
N(2)–
H(2B)Á Á ÁCl(1)#2
Symmetry transformations used to generate equivalent atoms: #1:
Àx + 1/2, y À 1/2, Àz + 1/2; #2 Àx + 1/2, y + 1/2, Àz + 1/2.
149.6
sulfoxide ligands towards the diamine, as seen from the
other cis angles, where the N–Ru–Cl angles are less
(<90ꢁ) when compared to the S–Ru–Cl angles (>90ꢁ).

4318
D. Sukanya et al. / Polyhedron 26 (2007) 4314–4320
3.5. Antimicrobial activity
to 16 h. The presence of DMSO alone was not sufficient
to cause the cleavage, so the combination of ruthenium
and DMSO might be the cause for the cleavage.
The antimicrobial activities of the new complexes were
screened against seven pathogenic bacteria. A clear zone
around the disc indicated inhibitory activity of the com-
pound on the organism. Depending upon the diameter of
the inhibition zone the new complexes were graded as sen-
sitive (<13 mm), intermediate (14–15 mm) or resistant
(>15 mm) against pathogenic bacteria. The intermediate
strains were also scored as resistant. Both complexes 5
and 6 were found to exhibit good activity against the spe-
cies under study. The activity was found to increase with
an increase in concentration of the metal complex used.
The complexes were found to exhibit moderate activity in
certain cases and in a few cases, against A. hydrophila
and S. faecalis, their sensitivity reached almost the values
of standard Chloramphenicol and Gentamicin.
From this, it is evident that the Schiff base first associ-
ates itself to the [RuCl2(DMSO)4] complex and then the
cleavage occurs. Coordination to metal can cause weaken-
ing or strengthening of the –C@N– group [38] and here the
former occurs resulting in hydrolytic cleavage immediately,
and the intermediate could not be isolated. The cleavage is
expected to be caused by trace amounts of water present in
ethanol. Bravo has reported a similar type of –C@N–
cleavage in platinum and palladium complexes and have
found that the hydrolysis is suppressed when the reaction
was handled under argon in dry solvents [39].
A few reports found relevant to our discussion is the
hydrolysis of N-benzylimines PhCH2N@C(H)Ar (Ar = Ph,
p-MeOC6H4) by trace water promoted by the ruthenium
complex [Ru2Cl4(dppb)2] [dppb = 1,4-bis(diphenylphosph-
ino)butane, Ph2P(CH2)4(PPh2)]. This reaction [40] is found
to proceed through an intermediate containing a g1-bonded
imine ligand, viz., [Ru2Cl4(dppb)2(PhCH2N @C(H)Ph)],
4. Mechanism for cleavage
In order to propose a cause and route for the –C@N–
cleavage, a number of reactions were carried out. To start
with, the ligands were refluxed in ethanol in the absence of
a metal complex for various time intervals, and no cleavage
was observed even after 96 h. The very fact that cleavage
does not occur in the absence of metal complex indicates
the involvement of the metal centre. The Schiff bases con-
stitute a series of molecules that are susceptible both to
hydrolytic cleavage and to coordination with metal ions.
It is believed that the formation of bonds between the posi-
tive metal ion and nitrogen brings about a labilization of
the nitrogen carbon double bonds, which are thereby ren-
dered more susceptible to hydrolytic cleavage [36].
It is known from our previous work [37] that the same
Schiff bases have acted as tetradentate ligands to form com-
plexes with [RuX3(PPh3)3]. Hence, we arrived at the con-
clusion that mere ruthenium alone is not sufficient for the
cleavage. To find out if DMSO alone can cause the cleav-
age, the reaction was carried out with an excess of DMSO
along with ethanol for various time intervals, from 1 h up
1
characterized by H and 31P NMR spectroscopy, to yield
free benzaldehyde and [Ru2Cl4(dppb)2 (NH2CH2Ph)].
Similarly, CuCl2 Æ nH2O has been found to promote the
hydrolysis of semicarbazones in acetonitrile, through a
mechanism involving simultaneous coordination of the lone
pair of the nitrogen and the C@O bond of the semicarbazone
to the metal ion [41]. A recent article [42] describes the chemo
selective hydrolysis of the iminic moiety in salicylaldehyde
semicarbazone promoted by [RuCl2(DMSO)4]. In concur-
rence with this, the following mechanism (Scheme 2) has
been suggested.
The cleavage is found to occur in the presence of a metal
centre, which brings about weakening of the coordinated
–C@N– bond. The presence of a trace amount of water
brings about cleavage. As a consequence of coordination
to the metal, the C@N group is highly polarized and nucle-
ophilic attack on the carbon atom of the C@N group may
occur. Attack of water on the C@N carbon leads to an
unstable amino-alcohol, which spontaneously breaks up
Table 4
Antimicrobial activity data for the new ruthenium(II) complexes
Sample
Concentration
A (mm)
B (mm)
C (mm)
D (mm)
E (mm)
F (mm)
G (mm)
5
1.50
1.00
0.75
0.50
0.25
33
31
29
29
28
27
21
15
12
12
30
22
22
18
16
22
16
13
13
13
19
18
15
15
15
25
16
15
14
12
15
14
14
12
11
6
1.50
1.00
0.75
0.50
0.25
24
20
20
20
14
20
20
15
14
14
18
16
16
15
14
25
24
22
20
14
18
18
18
16
14
22
18
17
15
15
17
15
12
12
11
A = Aeromonas hydrophila, B = Eschericia coli, C = Salmonella typhi, D = Streptococcus faecalis, E = Klebsiella pneumonia, F = Staphylococcus aureus,
G = Proteus mirabilis.

D. Sukanya et al. / Polyhedron 26 (2007) 4314–4320
4319
6. Supplementary material
OH
OH
CCDC 622118 contains the supplementary crystallo-
graphic data for [RuCl2(DMSO)2(o-pndn)]. These data
can be obtained free of charge via http://www.ccdc.cam.
ac.uk/conts/retrieving.html, or from the Cambridge Crys-
tallographic Data Centre, 12 Union Road, Cambridge CB2
1EZ, UK; fax: (+44) 1223-336-033; or e-mail: deposit@
ccdc.cam.ac.uk.
CH
N
HC
N
Cl
Cl
DMSO
DMSO
Ru
Ru
DMSO
DMSO
N
N
Cl
Cl
CH
HC
OH
OH
Acknowledgements
The diffractometer was funded by NSF Grant 0087210
by the Ohio Board of Regents Grant CAP-491 and by
YSU.
Cl
H2
N
DMSO
DMSO
HO
References
Ru
+
CH
N
O
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H2
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4320
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