Experimental and theoretical studies on methanesulfonic acid 1-methylhydrazide: Antimicrobial activities of its sulfonyl hydrazone derivatives

Article abstract of DOI:10.1016/j.molstruc.2009.09.002

Methanesulfonic acid 1-methylhydrazide (msmh) and its sulfonyl hydrazone derivatives, salicylaldehyde-N-methylmethanesulfonylhydrazone (salmsmh) and 2-hydroxy-1-naphthaldehyde-N-methylmethanesulfonylhydrazone (nafmsmh) were synthesized and characterized b

Full text of DOI:10.1016/j.molstruc.2009.09.002

Journal of Molecular Structure 938 (2009) 48–53
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Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
Experimental and theoretical studies on methanesulfonic acid
1-methylhydrazide: Antimicrobial activities of its sulfonyl hydrazone derivatives
Neslihan Özbek a, Saliha Alyar b, Nurcan Karacan b,
*
a Department of Primary Education, Faculty of Education, Ahi Evran University, 40100 Kırßsehir, Turkey
b Department of Chemistry, Science and Art Faculty, Gazi University, 06500 Ankara, Turkey
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 31 July 2009
Received in revised form 28 August 2009
Accepted 1 September 2009
Available online 6 September 2009
Methanesulfonic acid 1-methylhydrazide (msmh) and its sulfonyl hydrazone derivatives, salicylaldehyde-
N-methylmethanesulfonylhydrazone (salmsmh) and 2-hydroxy-1-naphthaldehyde-N-methylmethane-
sulfonylhydrazone (nafmsmh) were synthesized and characterized by using FT-IR, 1H NMR, 13C NMR, LC–
MS and elemental analysis. Conformation analysis of msmh based on DFT/B3LYP/6-311G(d) method was
performed. 1H and 13C shielding tensors of msmh for the most stable conformer were calculated with
GIAO/DFT/B3LYP/6-311++G(2d, 2p) methods in vacuo and various solvents such as DMSO, THF, acetoni-
trile, methanol and aqueous solution. The harmonic vibrational wavenumbers for the most stable con-
former were calculated using at B3LYP/6-311G(d) level. Antimicrobial activity of the compounds was
also screened against Gram-positive bacteria (Staphylococcus aureus ATCC 25923, Bacillus cereus RSKK
863) and Gram-negative bacteria (Escherichia coli ATCC 11230, Salmonella enterititis ATCC 40376, Pseudomo-
nos aeruginosa ATCC 28753) by both disc diffusion and micro dilution methods.
Keywords:
Antimicrobial activity
Sulfonyl hydrazone
Sulfonyl hydrazide
NMR spectra
DFT
Ó 2009 Elsevier B.V. All rights reserved.
1. Introduction
bution to the understanding of the rational drug design of sulfonyl
hydrazide. Antibacterial activities of msmh and its sulfonyl hydra-
Sulfonamides and sulfonyl hydrazones have been shown to be
active in several pharmacological tests, demonstrating antibacte-
rial, antitumor, diuretic, antiviral, antinociceptive activity, specific
zones obtained by the condensation of salicylaldehyde and naph-
thaldehyde were also evaluated against Gram-positive bacteria
(Staphylococcus aureus ATCC 25923, Bacillus cereus RSKK 863) and
Gram-negative bacteria (Escherichia coli ATCC 11230, Salmonella
enterititis ATCC 40376, Pseudomonos aeruginosa ATCC 28753) by
both disc diffusion and micro dilution methods.
enzyme inhibition such as carbonic anhydrase,
c-secretase HIV-
protease, metalloproteinase, and hormone regulation among oth-
ers [1,2].
Furthermore, sulfonyl-hydrazine carrying ion-exchange beads
were used as an ion-exchange support for adsorption of human
serum albumin (HSA) from aqueous solution [3]. Sulfonyl hydra-
zides grafted onto the nanoparticles are also used as polymerizable
foaming agent [4].
2. Experimental
2.1. Physical measurements
Despite to its importance in medicinal and polymeric fields,
only a small amount of papers on calculations of sulfonyl hydra-
zides and their derivatives have been reported so far [5–10]. In
our previous study, experimental and theoretical study of
methanesulfonic acid hydrazide was reported [11]. Recently, we
have published some calculations and experimental data of some
sulfonyl hydrazone [12,13] and their metal carbonyl complexes
[14,15].
The elemental analyses (C, H, N and S) were performed on a LES-
CO-CHSNO-9320 type elemental analyzer. The 13C NMR and 1H
NMR spectra were recorded on a Bruker WM-400 spectrometer
at 400 MHz and at ambient temperature using d6-DMSO solutions
with TMS as internal reference. IR spectrum was recorded in the
range of 4000–400 cmꢀ1 as KBr disc with Mattson 1000 FT spec-
trometer. LC/MS-EI was recorded on AGILENT 1100. TLC was con-
ducted on 0.25 mm silica gel plates (60F254, Merck). Chemicals
were obtained from Aldrich and used without further purification.
As part of our ongoing studies, the aims of the present work is to
study the conformational behavior of msmh, as well as its NMR
spectra from experimental and theoretical viewpoints as a contri-
2.2. Synthesis of msmh
Methanesulfonyl chloride (0.04 mol) in tetrahydrofuran
(25 mL) was added methylhydrazine (0.08 mol) in dropwise while
* Corresponding author. Tel.: +90 3122021117; fax: +90 3122122279.
E-mail address: nkaracan@gazi.edu.tr (N. Karacan).
0022-2860/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.molstruc.2009.09.002

N. Özbek et al. / Journal of Molecular Structure 938 (2009) 48–53
49
the temperature was maintained between 268 and 273 K. The
2.6. Determination of MIC for the bacteria
mixture was stirred for 24 h (completion of the reaction was
monitored by TLC), then solvent was evaporated. The colorless
crude compound was purified in THF/n-hexane by column chro-
matography then the product was crystallized from THF/n-hexane
mixture (3:1). Yield 65%; mp: 115–117 °C. EI-MS (70 eV) m/z:
248.2 (2 M+), 249.1 (2 M + 1)+, Elemental analysis: Calcd for
(C2H8SO2N2): C, 19.35; H, 6.45; N, 22.50; S, 22.80. Found: C,
19.45; H, 6.34; N, 22.45; S, 22.61.
E. coli ATCC 11230, P. aeruginosa ATCC 28753, S. enterititis ATCC
40376, S. aureus ATCC 25923, B. cereus RSKK 863 cultures were ob-
tained from Gazi University, Biology Department and Refik Saydam
Hygiene Center Culture Collection. Bacterial strains were cultured
overnight at 310 K in Nutrient Broth. These stock cultures were
stored in the dark at 277 K during the survey.
The antibacterial activity of the compounds was examined by
determination the minimum inhibitory concentration (MIC) in
accordance with CLNS methodology (NCCLS) [17,18]. All tests were
performed in Nutrient Broth supplemented with dimethyl sulfox-
ide at a final concentration of 10% (v/v) to enhance their solubility.
Bacterial strains were cultured overnight at 310 K in Nutrient
Broth. Briefly, test strains were suspended in Nutrient Broth by
adjusting to 0.5 McFarland. The test compounds dissolved in di-
methyl sulfoxide (DMSO) were first diluted to the highest concen-
2.3. Synthesis of salmsmh
Ethanolic solution of methanesulfonic acid 1-methylhydrazide
(0.65 g, 5.24 mmol) was added dropwise to an ethanolic solution
of salicylaldehyde (0.65 mL g, 6.25 mmol), maintaining the tem-
perature at about 268 K. Then, the mixture was stirred for 5–
8 h at room temperature. The precipitated product was crystal-
lized from ethanol/n-hexane (3:1) mixture. The yellow crystal-
line solid was dried in vacuo and stored at ethanol/n-hexane
tration (1000
dilutions were made in a concentration range from 15.6 to
1000
g mLꢀ1 in 10 mL sterile test tubes containing nutrient broth.
l
g mLꢀ1) to be tested, and then serial twofold
vapour. Yield 60%, mp 110–111 °C. IR (KBr) cmꢀ1
:
1622
l
t
(C@N), 1268 (CAO), 1314 as(SO2), 1152
t
t
t
s(SO2); 1H NMR
MIC values of compounds bacterial strains were determined based
(d6-DMSO) d: 2.31 ppm(t, 3H, CH3), 5.02 ppm (s, 3H, NACH3),
8,69 ppm (s, 1H, N@CH), 11.35 ppm (s, 1H, OH), 6.94–7.36 ppm
(m, ArH); 13C NMR(d6-DMSO) d: 40.22 ppm (CH3), 40.01 ppm
(N@CH3), 164.90 ppm (N@CH); 117.25–132.55 ppm (ArC); EI-
MS (70 eV) m/z: 228 (M+, 11.4%, M + 1, 3.7%); Anal. Calcd. for
C9H12SO3N2: C, 47.4; H, 5.30; N, 12.30; S, 14.03. Found: C,
47.6; H, 5.34; N, 12.37; S, 13.98.
on a micro-well dilution method with some modifications. Then
96-well plates were prepared by dispensing into each well 95
of nutrient broth and 5 L of the inoculums. 100 L from test com-
pounds initially prepared at the concentration of 1000
g mLꢀ1
was added into the first wells. Then, 100 L from their serial dilu-
lL
l
l
l
l
tions was transferred into 13 consecutive wells. The test com-
pounds in this study were screened two times against each
micro organism. The MIC values were determined from visual
examinations as beings the lowest concentration of the extracts
in the wells with no bacterial growth [19].
2.4. Synthesis of nafmsmh
Ethanolic solution of methanesulfonic acid 1-methylhydrazide
(0.32 g, 2.58 mmol) was added dropwise to an ethanolic solution
of 2-hydroxy-1-naphthaldehyde (0.66 g, 3.8 mmol), maintaining
the temperature at about 268 K. Then, the mixture was stirred
for 5 h at room temperature. The precipitated product was crystal-
lized from ethanol/n-hexane (4:1) mixture. The yellow crystalline
solid was dried in vacuo and stored at ethanol/n-hexane vapour.
2.7. Disc diffusion method
Bacterial susceptibility testing was performed by the disc diffu-
sion method according to the guidelines of Clinical and Laboratory
Standards Institute (CLSI) [20]. The sterilized (autoclaved at 393 K
for 30 min), liquefied Mueller Hinton agar (313–323 K) was inocu-
lated with the suspension of the micro organism (matched to 0.5
McFarland) and poured into a Petri dish to give a depth of 3–
4 mm. The paper discs impregnated with the test compounds
Yield 65%; mp: 132–133 °C. IR (KBr) cmꢀ1: 1621
(CAO), 1320 as(SO2), 1165
s(SO2); 1H NMR (d6-DMSO) d:
t(C@N), 1240 t
t
t
3.13 ppm (t, 3H, CH3), 3,45 ppm (s, 3H, NACH3), 8,80 ppm (s, 1H,
N@CH), 11.85 ppm (s, 1H, OH), 7.23–8.58 ppm (m, ArH); 13C
NMR (d6-DMSO) d: 35.69 ppm (CH3), 33.27 ppm (N@CH3),
157,61 ppm (N@CH); 109.68–144.08 ppm (ArC); EI-MS (70 eV)
m/z: 278 (M+, 10.1%, M + 1, 5.7%); Anal. Calcd. for C13H14SO3N2:
C, 56.12; H, 5.03; N, 10.07; S, 11.51. Found: C, 56.16; H, 5.06; N,
10.04; S, 11.59.
(60 lg) were placed on the solidified medium. Discs were placed
on agar plates and the cultures were incubated at 310 K for 24 h
for bacteria. Inhibition zones formed on the medium were evalu-
ated in mm. Ampicillin was chosen as a standard in antibacterial
activity measurements (positive control). DMSO poured disc was
used as negative control.
2.5. Theoretical calculations
3. Results and discussion
An extensive search for low energy conformations on the po-
tential energy surface (PES) of (msmh) was carried out by using a
systematic search with DFT/B3LYP/6-311G(d) levels. Vibration
frequencies calculated ascertain the structure was characterized
to be the stable structure (no imaginary frequencies). For the
NMR calculations, the optimized geometry at DFT/B3LYP/
6-311++G(2d, 2p) level in gas phase was used. 1H and 13C NMR
chemical shifts were calculated by GIAO method at DFT/B3LYP/
6-311++G(2d, 2p) level. The 1H and 13C shieldings were con-
verted into the predicted chemical shifts using TMS values, cal-
culated at the same level of theory. After being optimized at
DFT/B3LYP/6-31G(d) level, vibrational wavenumbers of the most
stable conformer were calculated at the same level. All calcula-
tions were performed on a Pentium IV computer with the de-
fault convergence criteria and using Gaussian 03 software
package [16].
3.1. Structure analysis
The numbering scheme and molecular geometry of msmh are
presented in Fig. 1. One-dimensional potential energy scans were
performed
for
three
torsion
angles-s1 O2ASAN1AC1,
s2 C2ASAN1AC1 and s3 C2ASAN1AN2 in the full range of 0–360°,
starting with the eclipsed conformation and increasing of 30° at
DFT/B3LYP/6-311G(d) (Figs. 2–4), to determine the all the possible
conformations in vacuo. As seen in Figs. 2–4, the energy profiles of
s1 shows local minima at about 150°, global minima at 210°, local
maxima at about 180°, 300° and global maxima at 60°. Second scan
for s2 shows two local minima at 90° and 270°, global minima at
330°, local maxima at 30°, 300° and global maxima at 180°. Final scan
for
s3 shows two local minima at about 120° and 270°, global minima
at about 360°, two local maxima at 60° and 300°, global maxima at

50
N. Özbek et al. / Journal of Molecular Structure 938 (2009) 48–53
Fig. 4. Energy profile for the rotation about C2ASAN1AN2 dihedral angle.
Fig. 1. Optimized geometry of msmh.
Fig. 2. Energy profile for the rotation about O2ASAN1AC1 dihedral angle.
Fig. 5. Optimized (DFT/B3LYP/6-311G(d)) geometries of conformations.
conformers. The conformer 1 (or 10) is the most stable form. Energy
difference between conformers 1 and 2 is 0.38 kcal/mol. The principal
differences between the two conformers lie in the orientation of
hydrogen atomofNH2 moiety withrespect toSO2 group. The percent-
Fig. 3. Energy profile for the rotation about C2ASAN1AC1 dihedral angle.
Table 1
Total energies calculated with DFT/B3LYP/6-311G(d) basis set of the conformers.
about 210°. After calculation, four conformers were characterized for
msmh. The structure of optimized geometries of the conformations is
illustrated in Fig. 5. Total and relative energies of the conformers and
the relative contribution of every conformation at 298.15 K according
to the Maxwell–Boltzmann statistical average are listed in Table 1.
The gauche conformation about the SAN bond, indicated by the tor-
Conformers
s1
s2
s3
Energy
DE
(kcal/mol)
(kcal/mol)
(1,10)
(2,20)
(3,30)
(4,40)
48.42
31.68
161.52
ꢀ27.99
162.51
145.14
ꢀ84.04
85.27
ꢀ67.32
ꢀ86.25
54.56
ꢀ144.04
ꢀ463842.08
ꢀ463841.70
ꢀ463839.23
ꢀ463836.39
(0.00)
(0.38)
(2.85)
(5.69)
sional angle s3, is important for the energy minimum of the msmh

N. Özbek et al. / Journal of Molecular Structure 938 (2009) 48–53
51
Fig. 6. 13C NMR spectrum of msmh.
age distributions for these conformers are 65.16 and 34.31% for (1)
and (2), respectively. The results allow us to predict the presence of
first two conformers at the room temperature.
In order to facilitate the interpretation of the NMR spectra,
quantum-chemical calculations were performed using B3LYP/6-
311G++(2d, 2p) basis set for the most stable conformer in several
phases [21]. 13C NMR and 1H spectra of msmh are given in Figs. 6
and 7. The experimental and calculated chemical shift values are
shown in Table 2. Calculations of the carbon chemical shifts in
gas phase gave the following results: 40.22 ppm for C AS and
39.80 ppm for CAN, which shows good agreement with experi-
mental values (40.32 ppm and 38.49 ppm, respectively). However,
the calculated proton shifts in gas phase conformed poorly to the
measured proton shifts. The comparison of calculated values at dif-
ferent solvents revealed that good conformity is obtained at DMSO
and water phases. This means that solvent effect on the carbon
atoms is relatively weak, whereas, on hydrogen atoms are very
strong, depending on solvent polarity. Experimental NH2 proton
shift (5.20 ppm) showed poor correlation with the calculated pro-
ton shifts (3.50 ppm in DMSO, 4.00 ppm in water).This suggests
Fig. 7. 1H NMR spectrum of msmh.

52
N. Özbek et al. / Journal of Molecular Structure 938 (2009) 48–53
Table 2
Experimental and calculated 13C and 1H NMR chemical shifts (ppm).
DFT/B3LYP/6-311++G(2d, 2p)
Gas
Aqueous
DMSO
THF
Methanol
Acetonitrile
Exp.
SAC
NAC
SACH3
NACH3
NH2
40.32
38.49
2.73a
2.76a
2.98a
42.60
39.79
3.18a
3.29a
4.00a
41.05
39.28
2.93a
3.18a
3.50a
41.36
39.48
2.90a
2.83a
3.37a
41.53
39.33
2.93a
2.84a
3.51a
41.54
39.33
2.93a
2.85a
3.51a
40.22
39.80
3.20(s)
3.40(s)
5.20(s)
a
Average values.
that NH2 protons have both intra molecular and intermolecular
hydrogen bonding.
3.2. Antibacterial activity
The harmonic and scaled harmonic vibrational wavenumbers of
the most stable conformer of msmh calculated with B3LYP/6-
311G(d) levels and scaled by 0.9739 were given in Table 3, exper-
imental data in solid phase and approximate assignment also given
in Table 3. The assignment were made by taking care of the vibra-
tional motions by using Gaussian View and by taking into consid-
eration the data reported in the literature for compounds that
contain the same functional fragments [11,22]. The infrared bands
of solid substance are generally not coincident in wavenumbers
due to intermolecular interactions in the crystal (correlation ef-
fects). As seen in Table 3, scaled harmonic frequencies agree with
the experimental data, except NH2 stretching vibrations. The dif-
ference between experimental data and calculated anharmonic
wavenumbers of NH2 stretching vibrations may be explained by
molecular association with hydrogen bonding in solid state. This
comment is in accordance with the data of Ienco et al. [11].
msmh, salmsmh and nafmsmh were screened for its antibacterial
activity against Gram-positive bacteria (S. aureus ATCC 25923, B.
cereus RSKK 863) and Gram-negative bacteria (E. coli ATCC
11230, S. enterititis ATCC 40376, P. aeruginosa ATCC 28753) by both
disc diffusion and micro dilution methods. The antibacterial activ-
ity results were presented in Tables 4 and 5. Microbiological results
indicated that the synthesized compounds possessed a broad spec-
trum of activity against the tested microorganisms and showed rel-
atively better activity against Gram-negative as compared to
Gram-positive bacteria.
msmh showed the highest activity with lowest MIC values
(25 lg/mL, 50 lg/mL) against Gram-negative bacteria P. aerugin-
osa, E. coli and S. enterititis, respectively. However, the sulfonyl
hydrazones showed a remarkable decrease in antibacterial activity
(100–500
lg/mL) than the parent sulfonyl hydrazide (25–100
lg/mL). The presence of primer amine group in the sulfonyl hydra-
zide may be responsible for their higher activity in comparison to
sulfonyl hydrazones [13,23,24]. Furthermore, antimicrobial activ-
ity of msmh is higher than aliphatic and aromatic disulfonamides
published in the literature [23,24].
Table 3
The calculated and scaled vibrational wavenumbers (cmꢀ1) of the global conformer
(1) of msmh.
Experimental DFT/B3LYP/6-
311G(d)
Approximate
assignment
Scaled
4. Conclusion
IR (solid)
Harmonic
In this study, energetically favorable conformations of the msmh
were investigated firstly at B3LYP/6-311G(d) theory level. The ob-
tained results indicated that at room temperature the molecule in
electronically ground state has two stable conformers. Harmonic
vibrational wavenumber, 1H and 13C shielding tensors of msmh
3353
3237
3125
3110
3080
3025
2980
2934
1697
1490
–
1451
1434
1418
1324
1314
1293
1233
1157
1126
–
3568
3438
3194
3175
3155
3095
3078
3002
1720
1517
1506
1483
1464
1454
1360
1342
1306
1248
1157
1135
1119
1017
997
3475
3348
3110
3092
3072
3014
2997
2923
1675
1477
1466
1444
1425
1416
1324
1306
1272
1215
1127
1105
1089
990
m
m
m
m
m
m
m
m
as(NH2)
s(NH2)
as(SACH3)
as(SACH3)
as(NACH3)
s(NACH3)
s(SACH3)
s(NACH3)
Table 4
d(NH2)
Antimicrobial activity of the compounds with micro dilution method.
das(NACH3)
das(NACH3)
das(SACH3)
das(SACH3
ds(NACH3)
Bacteria
MIC (lg/mL)
msmh
salmsmh
nafmsmh
E. coli ATCC 11230
50
25
50
100
100
125
125
125
250
500
100
62.5
100
125
125
P. aeruginosa ATCC 28753
S. enterititis ATCC 40376
S. aureus ATCC 25923
B. cereus RSKK 863
m
x
m
as(SO2)
(NH2) +
(CN) + (NACH3)
q(NACH3)
q
q
(NH2)
m
s(SO2
d(NSC)
(NN) + d(CNN)
d(SNC) + (NACH3)
(CH3) + d(HCS)
d(NACH3)
m
994
978
–
q
Table 5
Result of the antimicrobial test of compounds (disc potency 60
971
963
q
lg).
989
875
753
622
844
757
618
822
737
602
m
m
q
(SN)
(CS)
Bacteria
Diameter of inhibition zone (mm)
msmh
salmsmh
nafmsmh
Ampicillin
(NACH3) + d(SNC)
(10 lg/disc)
523
–
455
409
501
486
463
412
488
473
451
401
d(SO2)
(SO2)
(SO2)
(NH2)
q
x
s
E. coli ATCC 11230
21
25
20
17
15
10
10
11
8
12
12
13
9
11
10
10
16
12
P. aeruginosa ATCC 28753
S. enterititis ATCC 40376
S. aureus ATCC 25923
B. cereus RSKK 863
as = asymmetric, s = symmetric, d = bending,
ing, = wagging.
m = stretching, q = rocking, s = twist-
7
10
x

N. Özbek et al. / Journal of Molecular Structure 938 (2009) 48–53
53
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for the most stable conformer were calculated. msmh showed the
highest antimicrobial activity against Gram-negative bacteria.
The sulfonyl hydrazones showed a remarkable decrease in antibac-
terial activity than the parent sulfonyl hydrazide.
[15] O.S. Senturk, U. Ozdemir, S. Sert, N. Karacan, F. Ugur, J. Coord. Chem. 60 (2007)
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Acknowledgements
[16] M.J. Frisch, G.W. Trucks, H.B. Schlegel, G.E. Scuseria, M.A. Robb, J.R. Cheeseman,
J.A. Montgomery Jr., T. Vreven, K.N. Kudin, J.C. Burant, J.M. Millam, S.S. Iyengar,
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M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, M. Klene, X. Li, J.E. Knox,
H.P. Hratchian, J.B. Cross, C. Adamo, J. Jaramillo, R. Gomperts, R.E. Stratmann,
O. Yazyev, A.J. Austin, R. Cammi, C. Pomelli, J.W. Ochterski, P.Y. Ayala, K.
Morokuma, G.A. Voth, P. Salvador, J.J. Dannenberg, V.G. Zakrzewski, S.
Dapprich, A.D. Daniels, M.C. Strain, O. Farkas, D.K. Malick, A.D. Rabuck, K.
Raghavachari, J.B. Foresman, J.V. Ortiz, Q. Cui, A.G. Baboul, S. Clifford, J.
Cioslowski, B.B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, R.L.
Martin, D.J. Fox, T. Keith, M.A. Al-Laham, C.Y. Peng, A. Nanayakkara, M.
Challacombe, P.M.W. Gill, B. Johnson, W. Chen, M.W. Wong, C. Gonzalez, J.A.
Pople, Gaussian, Inc., Pittsburgh PA., Gaussian 03 (Revision B.04), 2003.
[17] P.A. Wayne, National Committee for Clinical Laboratory Standards, Approved
Standard M 7-A4, 1997.
The authors thank the TUBITAK (Grant No. 104 T 390) and Gazi
University BAP (Grant No. 05/2005-59) for the financial support of
this project.
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