Spectral and thermal studies on ruthenium carbonyl complexes with 5-trifluoromethyl-2,4-dihydropyrazol-3-one ligands

Article abstract of DOI:10.1016/j.saa.2006.08.043

Reactions of the cluster compound [Ru₃(CO)₁₂] with 5-trifluoromethyl-2,4-dihydropyrazol-3-one (HL¹), 4-(2,4-dichlorophenylhydrazono)-5-trifluoromethyl-2,4-dihydropyrazol-3-one (H₂L²), 4-(3-fluoropheny

Full text of DOI:10.1016/j.saa.2006.08.043

Spectrochimica Acta Part A 67 (2007) 852–857
Spectral and thermal studies on ruthenium carbonyl complexes
with 5-trifluoromethyl-2,4-dihydropyrazol-3-one ligands
Ahmed A. Soliman∗
Department of Chemistry, Faculty of Science, Cairo University, Giza, Egypt
Received 23 July 2006; received in revised form 24 August 2006; accepted 29 August 2006
Abstract
Reactions of the cluster compound [Ru3(CO)12] with 5-trifluoromethyl-2,4-dihydropyrazol-3-one (HL1), 4-(2,4-dichlorophenylhydrazono)-
5-trifluoromethyl-2,4-dihydropyrazol-3-one (H2L2), 4-(3-fluorophenylhydrazono)-5-trifluoromethyl-2,4-dihydropyrazol-3-one (H2L3), 4-(3-
trifuoloromethyl-phenylhydrazono)-5-trifluoromethyl-2,4-dihydropyrazol-3-one (H2L4) and 4-(3-nitrophenylhydrazono)-5-trifluoromethyl-2,
4-dihydropyrazol-3-one (H2L5) have been carried out in benzene and under reduced pressure. The structures of the isolated complexes were
elucidated using elemental analyses, IR, UV–vis, mass and NMR spectroscopy. All the complexes are diamagnetic and have trigonal bipyramidal
structures with general formulae [Ru(CO)4(HL1)] and [Ru(CO)3(H2L2–5)]. The thermal decompositions of the complexes were studied in
correlation with the mass spectral fragmentation patterns.
© 2006 Elsevier B.V. All rights reserved.
Keywords: Ruthenium; Pyrazolone derivatives; IR spectra; UV–vis; NMR; Mass; Thermal analysis
1. Introduction
In this article we report the preparation of ruthenium
carbonyl derivatives of 5-trifluoromethyl-2,4-dihydropyrazol-
3-one (HL1), 4-(2,4-dichlorophenyl-hydrazono)-5-trifluorom-
ethyl-2,4-dihydropyrazol-3-one (H2L2), 4-(3-fluoro-phenylhy-
drazono)-5-trifluoromethyl-2,4-dihydropyrazol-3-one (H2L3),
4-(3-trifuoloromethylphenylhydrazono)-5-trifluoromethyl-2,4-
dihydropyrazol-3-one (H2L4) and 4-(3-nitrophenylhydrazono)-
5-trifluoromethyl-2,4-dihydropyrazol-3-one (H2L5), Scheme 1.
From the structural point of view, the ligands (H2L2–5) con-
tain an azo (N N) group in conjugation with C N group. Such
systems have strong ␲ acceptor ability, which could stabilize the
metals in their lower oxidation states [18–21]. Previous stud-
ies of ruthenium(II) complexes [22–24] demonstrated that the
extent of this stabilization depends on the N-hetero cyclic ring
to which the arylazo linkage is attached. Furthermore, the pres-
ence of more than one C N group in the heterocyclic ring of the
ligands under investigation strengths their ␲ acceptor ability.
Fluorinated compounds in general and fluorinated hetero-
cycles in particular are the focus of much interest in mod-
ern medicinal chemistry [1]. Various pharmaceutical reagents
bearing trifluoromethyl groups are of special interest as they
exhibit wide ranging biological properties [1,2]. Many efficient
methods for the introduction of a trifluoromethyl group into
organic molecules have been developed. Trifluoromethyl-1,3-
dicarbonyl compounds proved to be versatile building blocks for
a wide variety of trifluoromethyl substituted heterocycles. These
include pyrazoles [3,4], isoxazoles [5], thiazoles [6], pyridines
[7], pyrimidines [8] and pyrones [9]. The trifluoromethyl sub-
stituted compounds were found to possess biological activi-
ties as herbicides [10], fungicides [11], analgesic agents [12],
antipyretic agents [13] and inhibitors for platelet aggregation
[14]. Recently, much attention has been focused on pyrazoles
and their metal complexes as antiviral and anticancer agents
[15]. On the other hand, metal carbonyl derivatives specially
those of N and NO donor ligands are important routes to pre-
pare interesting metal carbonyl complexes [16,17].
2. Experimental
2.1. Materials
Ru3(CO)12 were supplied by Aldrich. 5-Trifluoromethyl-2,4-
dihydropyrazol-3-one (HL1) is prepared from the reac-
tion of ethyl 4,4,4-trifluoro-3-oxobutanoate with hydrazine
∗
Tel.: +20 25676565; fax: +20 25757556.
E-mail addresses: ahmedsoliman61@gmail.com,
ahmedsoliman2@hotmail.com.
1386-1425/$ – see front matter © 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.saa.2006.08.043

A.A. Soliman / Spectrochimica Acta Part A 67 (2007) 852–857
853
Scheme 2. Keto–enol tautomerism of ligands. (a) Enol form and (b) keto form.
thermogravimetric analyzer TGA-50H in presence of nitrogen
atmosphere with a heating rate of 10 ◦C min−1
.
Scheme 1. The structures of ligands. R = 2,4-dichloro (H2L2), 3-fluoro (H2L3),
3-trifluromethyl (H2L4) and 3-nitro (H2L5).
2.3. Syntheses of complexes
in ethanol in the presence of sulfuric acid [3,16,25]. 4-(2,4-Di-
chlrophenylhydrazono)-5-trifluoromethyl-2,4-dihydropyrazol-
3-one (HL2), 4-(3-fluorophenylhydrazono)-5-trifluorome-
thyl-2,4-dihydropyrazol-3-one (HL3), 4-(3-trifluoromethyl-
phenylhydrazono)-5-trifluoromethyl-2,4-dihydropyrazol-3-one
(HL4), and 4-(3-nitrophenylhydrazono)-5-trifluoromethyl-
2,4-dihydropyrazol-3-one (HL5) were provided by professor
Hussein F. Zohdi, Department of Chemistry, Faculty of Science,
Cairo University. All solvents were of analytical grade and
were purified by distillation before use.
A
mixture of Ru3(CO)12 (0.10 g, 0.16 mmol) and
either 5-trifluoromethyl-2,4-dihydropyrazol-3-one (HL1)
(0.049 g, 0.32 mmol), 4-(2,4-dichlorophenylhydrazono)-5-
trifluoromethyl-2,4-dihydro-pyrazol-3-one (H2L2) (0.104,
0.32 mmol), 4-(3-fluorophenylhydrazono)-5-trifluoromethyl-
2,4-dihydropyrazol-3-one (H2L3) (0.088, 0.32 mmol), 4-(3-trif-
luoro-methylphenylhydrazono)-5-trifluoromethyl-2,4-dihydro-
pyrazol-3-one (H2L4) (0.104, 0.32 mmol) or 4-(3-nitrop-
henylhydrazono)-5-trifluoromethyl-2,4-dihydropyrazol-3-one
(H2L5) (0.096, 0.32 mmol) in ca. 40 ml benzene was degassed
and then heated to reflux for 8 h. The reaction mixtures were
cooled and the solvent was removed under vacuum. The brown
residue was washed by hot benzene followed by petroleum
ether and then recrystallized from hot ethanol. The complexes
were left to dry on a vacuum line for several hours. Elemental
analysis and the mass spectral data (molecular ion peak) are
given in Table 1.
2.2. Instruments
Elemental analyses (C, H, N and S) were performed in the
Center Laboratory Unit (CLU) of UAE University; the analyses
have been repeated twice. The IR spectra (KBr pellets) were
measured on a NEXUS 470 FT-IR spectrometer. The UV–vis
measurements were performed on a Cary 50 Conc UV–vis spec-
1
trophotometer. H NMR measurements were carried out on a
3. Results and discussion
Spectrospin-Bruker AC 200 MHz NMR Spectrometer. Samples
were dissolved in DMSO using TMS as an internal reference.
Conductometric measurements (DMF solutions at 25 ◦C) were
performed on a Metrohm 660 conductivity meter. The molar
magnetic susceptibilities (Gouy method) were measured on a
SherwoodScientificmagneticsusceptibilitybalance. Massspec-
tra of the solid complexes (FAB technique) were recorded on
a JMS-AX500 Double focusing Mass Spectrometer. Thermal
analyses of the complexes were carried out using a Shimadzu
3.1. IR and 1H NMR spectra
The 5-trifluoromethyl-2,4-dihydropyrazol-3-one (HL1) lig-
and and its azo derivatives (H2L2–5) were found to exist in
tautomeric equilibria. The enol form (Scheme 2a) persists in
solution while the keto form (b) exists in the solid state. The keto
isomer was indicated by the presence of the carbonyl stretch-
ing vibrations at 1749–1670 cm−1 and the NH vibrations at
Table 1
Elemental analysis and mass spectrometry data of ligands and complexes
Compound
Molecular weight
Found (calcd.) (%)
C
Mass (m/z)
UV–vis (λmax)
H
N
HL1
152.07
325.07
274.17
324.18
301.18
365.14
510.17
459.24
509.28
486.28
32.49 (31.59)
37.67 (36.95)
42.37 (43.81)
39.96 (40.75)
40.63 (39.88)
26.93 (26.30)
31.10 (30.61)
34.07 (34.00)
33.27 (33.02)
36.22 (32.11)
1.97 (1.99)
1.41 (1.55)
1.81 (2.21)
1.84 (1.87)
1.94 (2.01)
0.86 (0.82)
1.10 (1.00)
1.34 (1.32)
1.10 (1.19)
1.41 (1.24)
18.42 (18.56)
17.41 (17.24)
19.90 20.43)
16.86 17.28)
23.18 (23.25)
7.88 (7.67)
11.20 (10.98)
11.97 (12.20)
11.12 (11.00)
14.91 (14.40)
152
325
275
324
301
366
511
459
510
484
373, 289
H2L2
432, 373, 267
423, 373, 281
420, 373, 264
421, 373, 261
373, 292, 276
430, 373, 264
416, 370, 268
419, 369, 269
414, 371, 267
H2L3
H2L4
H2L5
Ru(CO)4(HL1)
Ru(CO)3(H2L2)
Ru(CO)3(H2L3)
Ru(CO)3(H2L4)
Ru(CO)3(H2L5)

854
A.A. Soliman / Spectrochimica Acta Part A 67 (2007) 852–857
Table 2
Important IR data of the ligands and their complexes
Compound
ν(OH)
azoν(NH)
ν(C O)
δ(OH)
ν(C O)
ν(M O)
ν(M N)
HL1
–
–
–
–
–
1749 m
1735 s
1695 s
1702 s
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
H2L2
3302m
3289m
3288m
3264m
–
3205mb
3217mb
3226mb
3175w
H2L3
H2L4
H2L5
–
1682 s
Ru(CO)4(HL1)
Ru(CO)3(H2L2)
Ru(CO)3(H2L3)
Ru(CO)3(H2L4)
Ru(CO)3(H2L5)
3434mb
3305mb
3457mb
2144 sh, 2078 s, 2020 s
2058 s, 2022 s, 1998 s
2135 sh, 2077 s, 2013 s
2057 s, 2023 s, 1998 s,
2067 s, 2021 s, 1998 sh
1420m
1377m
1420m
1434m
1424m
1159s
1163m
1167s
1188s
1159s
–
575w
590w
606w
575w
541w
641w
676m
640w
591w
3431mb
s: strong, m: medium, mb: medium broad, w: weak.
3287–3164 cm−1 in their IR spectra (Table 2). On the other hand,
the enol form was confirmed by the presence of the OH singlet
(ca. 12.80 ppm) in the NMR spectra of the ligands in DMSO
(Table 4) (vide infra).
in bonding was confirmed by the presence of a vibration at
3434 cm−1 in the IR spectrum of the complex.
1
The H NMR spectra of the [Ru(CO)4(HL1)] complex was
examined in comparison with those of the ligand (HL1). The
ligand showed singlet at 12.69–12.90 ppm (Table 3), with an
integration corresponding to one proton, which is assigned to
the enol OH group. This singlet is also observed unshifted in
the spectrum of Ru(CO)4(HL1) indicating the non-participation
of the OH group in coordination. Another singlet is observed in
the HL1 spectrum at 5.65 ppm, with integration of two protons,
which is assigned two the protons of the CH2 group.
Interaction of the cluster compound Ru3(CO)12 with
either 4-(2,4-dichlrophenylhydrazono)-5-trifluoromethyl-2,4-
dihydropyrazol-3-one (H2L2), 4-(3-fluorophenylhydrazono)-
5-trifluoromethyl-2,4-dihydropyrazol-3-one (H2L3), 4-(3-tri-
fluoromethylphenylhydrazono)-5-trifluoromethyl-2,4-dihydro-
pyrazol-3-one (H2L4) or 4-(3-nitrophenylhydrazono)-5-
trifluoromethyl-2,4-dihydropyrazol-3-one (H2L5) yielded the
tricarbonyl mononuclear derivative [Ru(CO)3(H2L2–5)]. The
magnetic susceptibility measurements of the complexes showed
that they were diamagnetic with zerovalent ruthenium in a
Reaction of Ru3(CO)12 with 5-trifluoromethyl-2,4-
dihydropyrazol-3-one (HL1) resulted in the formation of a dark
brown complex with a molecular formula [Ru(CO)4(HL1)],
Scheme 3. The magnetic measurement revealed the diamagnetic
nature of the complex. The IR spectrum of the HL1 displayed
characteristic bands due to ν(NH), ν(CO) and ν(C N) at 3287,
1749 and 1670 cm−1, respectively. The first two bands were
disappeared from the spectrum of [Ru(CO)4(HL1)] complex.
This finding could be explained on the basis that the ligand
was in its enol form. The band due to the azomethine group
ν(C N) was found to be shifted to higher wave number in
the IR spectrum of the complex indicating its participation in
coordination [26,27]. Magnetic susceptibility measurement
revealed that the complex is diamagnetic indicating a zerovalent
ruthenium complex with five coordinate environment. Also,
the IR spectrum of the complex displayed three bands at
2100, 2078, 2020 and 1995 cm−1, which could be assigned to
asymmetric and symmetric CO stretching vibrations of four
carbonyl groups coordinated terminally to the metal. From the
number and pattern of the CO bands, it concluded that they
bonded to metal in two cis and two trans positions of a trigonal
bipyramidal structure [28]. The HL1 ligand coordinated the
Ru metal through the heterocyclic nitrogen of the C N group
attached to the OH (Scheme 3). This coordination is more
likely than that of the other nitrogen because of the basicity
is believed to decrease by the inductive effect of the trifluro
methyl group. In addition, the IR spectrum showed a Ru N
vibration at 567 cm−1. The non-participation of the OH group
Table 3
Important 1H NMR data for HL1 and HL2–5 and their complexes
Compound
NMR data (ppm)
HL1
H2L2
12.81 s (1H; OH), 5.65 s (2H, CH2)
12.90 s (1H; OH), 7.52–7.82 m (3H; Ph),
3.40 s (1H, azoNH)
H2L3
H2L4
H2L5
12.67 s (1H; OH), 7.10–7.52 m (4H; Ph),
3.87 s (1H, azoNH)
12.69 s (1H; OH), 7.59–7.99 m (4H; Ph),
3.69 s (1H, azoNH)
12.69 s (1H; OH), 7.67–8.45 m (4H; Ph),
4.76 s (1H, azoNH)
12.84 s (1H; OH), 5.65 s (2H, CH2)
12.91 s (1H; OH), 7.57–7.86 m (3H; Ph),
3.54 s (1H, azoNH)
Ru(CO)4(HL1)
Ru(CO)3(H2L2)
Ru(CO)3(H2L3)
Ru(CO)3(H2L4)
Ru(CO)3(H2L5)
12.65 s (1H; OH), 7.61–7.99 m (4H; Ph),
4.14 s (1H, azoNH)
12.66 s (1H; OH), 7.59–7.99 m (4H; Ph),
3.94 s (1H, azoNH)
12.70 s (1H; OH), 7.7–8.49 m (4H; Ph), 4.89
s (1H, azoNH)
Scheme 3. The proposed structure of [Ru(CO)4(HL1)] complex.

A.A. Soliman / Spectrochimica Acta Part A 67 (2007) 852–857
855
the range 2024–1943 cm−1 and assigned to two axial and
one equatorial CO groups [33]. Furthermore, three vibrations
(2054, 1978 and 1920 cm−1) were found in the IR spectrum
of [Ru(CO)3(LH2)] (LH2 = maleic hydrazide) complex [34],
which was assigned to two axial and one equatorial CO groups;
LH2 ligand coordinated through two equatorial sites. Similar
findings were observed in case of [Ru(CO)3(dpq)] (dpq = 2,3-
bis(2ꢀ-pyridyl)quinoxaline) complex [35].
3.2. The UV–vis spectra
The HL1 displayed two absorption bands at 373 and 289 nm
which, can be assigned to the n–␲ transitions within the non-
Scheme 4. The proposed structure of [Ru(CO)3(H2L)] complexes.
*
tautomeric (CF3C N) and tautomeric (OH C N) azomethine
groups. The first band is also found in the spectra of the H2L2–5
ligands. In addition, the later ligands displayed two additional
bands at 420–432 and 261–281 nm, which can be assigned to
the n–␲ and ␲–␲ transition within the azo group and the
phenyl (C C) moieties, respectively. The spectra of the com-
plexes showed the same bands with slight shifts due to complex
formation (Table 1).
trigonal bipyramidal geometry. The IR spectra of the complexes
showed the characteristic bands of ligands with the appropriate
shifts due to complex formation (Table 2). In addition, the IR
spectrum of these complexes exhibited three vibration bands
in the terminal metal carbonyl range (2144–1998 cm−1) with
symmetry of 2aꢀ + aꢀꢀ. The number and pattern of these bands
suggested the asymmetric and symmetric stretching frequencies
of two axial and one equatorial CO groups attached to ruthenium
in trigonal bipyramid environment, Scheme 4 [28,29]. The
other two equatorial positions were occupied by the bidentate
ligands through the NH and the OH groups. This is indicated by
the shift in the NH bands in the IR spectra of complexes, which
appeared as a very weak vibration at (3164–3226 cm−1) and
the appearance of medium broad vibration at 3305–3457 cm−1
(νOH) and at 1377–1434 cm−1 (δOH). The shifts in νOH
and δOH to lower frequencies indicated the participation of
the OH groups in bonding without proton displacement [30].
Furthermore, the participation of the NH and the OH in bonding
is also indicated from the far IR spectrum of the complexes as
the non-ligand bands, which were observed at 591–676 cm−1
due to Ru O and 541–606 cm−1 due to Ru N bonds [26,31].
The 1H NMR spectra of the ligands (H2L2–5) showed singlet
at 12.69–12.90 ppm (Table 3), with an integration corresponding
to one proton, which is assigned to the enol OH group. This
*
*
3.3. Thermogravimetric analysis
The reported ruthenium complexes were found to be air sta-
ble and have higher thermal stability. These properties along
with their possibility to use as catalysts in epoxidation reactions
[30] have prompted us to investigate their thermal decompo-
sition. The thermal study was carried out using the thermo-
gravimetric technique with a heating rate of 10 ◦C min−1. The
decomposition ranges, mass losses and mass loss assignments
are given in Table 4. The decomposition products are com-
pared with the most abundant fragmentation patterns of the mass
spectral to evidence the decomposition schemes of the com-
plexes. The decomposition mass losses were found in agreement
with the starting formulae weight proposed from the elemental
analysis which may be taken as extra evidence for the cor-
rectness of these formulae. All complexes start decomposition
with the loss of the carbonyl groups and ended with RuO as
metallic residue. Ru(CO)4(HL1) decomposes in two steps, the
first step observed in the temperature range 70–152 ◦C with a
total mass loss of 7.67% (mass = 28) which can be assigned
to the removal of one CO group. The last decomposition step
(186–410 ◦C) with a mass loss of 60.30% (mass = 220.07) is
assigned to the removal of the other carbonyls groups along with
the organic ligand leaving RuO (117.07, 34.27%) as the metal-
lic residue. Ru(CO)3(H2L2) decomposes in three steps, the first
decomposition step (100–181 ◦C) with a mass loss of 11.12%
(mass = 56.7) is assigned to the removal of two CO group. The
second decomposition step occurred in the temperature range
181–271 ◦C with a mass loss of 60.43% (mass = 309), which
is assigned to the removal of the main part of the organic lig-
and. The full decomposition of the ligand is completed in the
final step (271–462 ◦C) leaving RuO (117.07, 22.92%) as the
metallic residue. Ru(CO)3(H2L3) decomposes to RuO (117.07,
25.34%) in two steps spreading over the temperature range
singlet is slightly shifted in the spectra of the Ru(CO)3(H2L2–5
)
complexes indicating the participation of the OH group of the
H2L2–5 ligands in coordination without proton displacement.
The H2L2–5 ligands displayed singlet at 3.40–3.87 ppm assigned
to the azoNH. This singlet is found slightly shifted in the spectra
of Ru(CO)3(H2L2–5) indicating the coordination manner of the
azoNH without proton displacement. These findings meet the
requirement for zerovalent ruthenium environment with trigonal
bipyramidal Ru(CO)3(H2L2–5) complexes.
Reaction of Ru3(CO)12 with salicylideneimine-2-thiophenol
Schiff base (satpH2) gave [Ru(CO)4(satpH)] which exhib-
ited a pattern of four CO stretching frequencies in the range
2050–1946 cm−1 with a symmetry (2a + b1 + b2) due to four car-
bonyl groups in a cis and trans positions [32,28]. On the other
hand, reactions of Ru3(CO)12 with 2-(2ꢀ-pyridyl)benzimidazole
(HPBI) in the presence of either pyridine (py) or dipyridine
(dpy) resulted in the formation of the tricarbonyl derivatives
[Ru(CO)3(HPBI)]·py and [Ru(CO)3(HPBI)]·dpy. These com-
plexes showed three CO stretching frequencies (2aꢀ + aꢀꢀ) in

856
A.A. Soliman / Spectrochimica Acta Part A 67 (2007) 852–857
Table 4
Thermoanalytical results (TGA) and mass spectrometry data for ruthenium and molybdenum complexes
Complex
Formulae TG range (◦C) DTmax (◦C) Mass loss found
Assignment of the
removed species
Metallic residue
found (calcd. %)
m/z values (most
abundant peaks)
weight
(calcd. %)
Ru(CO)4(HL1)
365.14
70–152
131
7.64 (7.67)
Loss of CO
RuO
364, 337, 304, 228,
136, 130, 117, 88, 78,
57
186–410
100–181
324
137
60.30 (60.28)
11.12 (11.00)
Loss of HL1 (O) + 3CO
Loss of 2 CO
34.27 (32.06)
RuO
Ru(CO)3(H2L2) 510.17
511, 458, 404, 311,
288, 262, 233, 311,
181, 159, 129, 117, 68
181–271
271–462
230
408
60.43 (60.58)
5.52 (5.49)
Loss of H2L2 (O)
Loss of CO
22.92 (22.95)
RuO
Ru(CO)3(H2L3) 459.24
Ru(CO)3(H2L4) 509.28
100–250
170
18.30 (18.29)
Loss of 3 CO
430, 386, 376, 274,
258, 179, 117, 95, 57
250–390
109–171
336
152
56.31 (56.22)
11.12 (10.99)
Loss of rest of H2L3 (O)
Loss of 2 CO
25.34 (25.49)
RuO
509, 453, 323, 308,
305, 224, 178, 117,
69, 56
300–580
90–185
450
111
66.01 (66.03)
5.56 (5.76)
Loss of CO + H2L4 (O)
Loss of CO
22.76 (22.99)
RuO
Ru(CO)3(H2L5) 486.28
486, 458, 418, 402,
288, 257, 237, 181,
159, 129, 117
185–248
248–352
211
313
11.12 (11.52)
58.87 (58.789)
Loss of 2CO
Loss of H2L5 (O)
247.44 (24.07)
100–390 ◦C with mass losses of 18.30% (mass = 84) and 56.31%
(mass = 258) which are assigned to the removal of the carbonyl
groupsandtheorganicligand;respectively. Ru(CO)3(H2L4)was
found to decompose also in two steps with a decomposition
manner similar to Ru(CO)3(H2L3). The Ru(CO)3(H2L5) com-
plex decomposes in three steps within the temperature range
90–352 ◦C. The three CO groups were found to be removed in
the first two decomposition steps (90–185 ◦C, 185–248 ◦C) with
a total mass loss of 16.68% while the organic part was found to
be removed in the last step (248–352 ◦C) with a mass loss of
58.87% (mass = 285.89) ended with RuO (117.07, 27.44%).
References
[1] L.F. Lee, F.M. Schleppnik, R.W. Schneider, D.H. Campbell, J. Heterocycl.
Chem. 27 (1990) 243.
[2] P. Bravo, D. Dillido, G. Resnati, Tetrahedron 50 (1994) 8827.
[3] Hussein F. Zohdi, A.H.H Elghandour, N.M. Rateb and M.M. Sallam, J.
Chem. Res. (1992) (S)396, (M)3015.
[4] V.I. Saloutin, Y.V. Burgart, O.G. Kuzueva, C.O. Kappe, O.N. Chupakhin,
J. Fluorine, Chemistry 103 (2000) 17.
[5] L. Zhi, C.M. Tegly, K.B. Marschke, T.K. Jones, Bioorg. Med. Chem. Lett.
9 (1999) 1008.
[6] J.P. Edwards, S.J. Weat, C.L.F. Pooley, K.B. Marschke, L.J. Farmer, T.K.
Jones, Bioorg. Med. Chem. Lett. 8 (1998) 745.
[7] C.M. Tice, L.M. Bryman, Tetrahedron 57 (2001) 2689.
[8] C.O. Kappe, S.F. Falsone, W.M.F. Fabian, F. Belaj, Heterocycles 51 (1999)
77.
3.4. Conclusion
[9] L.F. Lee, G.L. Stiks, Y.L. Sing, M.L. Miller, M.G. Dolson, J.E. Normansell,
S.M. Auinbauh, Pestic. Sci. 31 (1991) 555.
Interaction of Ru3(CO)12 with HL1 resulted in the formation
of the Ru(CO)4HL1 complex with trigonal bipyramidal struc-
ture with two cis CO and two trans CO groups, while the fifth
coordination site is occupied by the tautomeric nitrogen of the
ligand. On the other hand, the interaction of Ru3(CO)12 with the
ligands (H2L2–H2L5) resulted in the formation of complexes
with general formulae Ru(CO)3(HL2–5). The complexes were
proved to have trigonal bipyramidal structure with two axial
and one equatorial CO groups. The other coordination positions
are occupied by the ligands through the azoNH group and the
OH group two form a six-membered chelate.
[10] J.-C. Jung, E.B. Watkins, M.A. Avery, Tetrahedron 58 (2002) 3639.
[11] L.K. Kenneth, J.F. John, E.S. Kurt, F.M. James, M. Brenda, T. Theresa, M.
Diana, L.M. Michael, J. Med. Chem. 39 (1996) 3920.
[12] T.P. Gregory, C.D. Darlene, M.S. David, Pestic. Biochem. Phys. 60 (1998)
177.
[13] S.G. Kucukguzel, S. Rollas, H. Erdeniz, A.C. Kiraz, M. Ekinci, A. Vidin,
Eur. J. Med. Chem. 35 (2000) 761.
[14] A.E. Mutalib, S.-Y. Chen, R.J. Espina, J. Shockcor, S.R. Prakash, L.-S.
Gan, Chem. Res. Toxicol. 15 (2002) 63.
[15] S.A. Gamage, J.A. Spicer, G.W. Rewcastle, J. Milton, S. Sohal, W. Dan-
gerfield, P. Mistry, N. Vicker, P.A. Charlton, W.A. Denny, J. Med. Chem.
45 (2002) 740.
[16] K. Sukcharoenphon, K.B. Capps, K.A. Abboud, C.D. Hoff, Inorg. Chem.
40 (2001) 2402.
Acknowledgement
[17] J. van Slageren, D.J. Stufkens, Inorg. Chem. 40 (2001) 277.
[18] R.A. Krause, K. Krause, Inorg. Chem. 19 (1980) 2600.
[19] S. Goswami, A.R. Chakravarty, A. Chakravaorty, Inorg. Chem. 20 (1981)
2246.
The author wishes to thank Professor Hussein F. Zohdi,
Department of Chemistry, Faculty of Science, Cairo University
for providing the ligands.
[20] D. Datta, A. Chakravaorty, Inorg. Chem. 22 (1983) 1085.

A.A. Soliman / Spectrochimica Acta Part A 67 (2007) 852–857
857
[21] B.K. Ghosh, S. Goswarmi, A. Chakravorty, Inorg. Chem. 22 (1983)
3358.
[29] S.A. Ali, A.A. soliman, M.M. Aboaly, R.M. Ramadan, J. Coord. Chem. 55
(10) (2002) 1161.
[22] T.K. Misra, C. Sinha, Transition Met. Chem. 24 (1999) 168.
[23] T.K. Misra, C. Sinha, Transition Met. Chem. 24 (1999) 172.
[24] J.P. Collman, L.S. Hegedus, Principles and Application of Organotransition
Metal Chemistry, University Science Book, California, 1980.
[25] I.M. Abdou, A.M. Saleh, H.F. Zohdi, Molecules 9 (2004) 109.
[26] A.A. Soliman, W. Linert, Synth. React. Inorg. Met-Org. Chem. 29 (1999)
1133.
[30] G. Bandoli, T.I.A. Gerber, R. Jacobos, J.G.H. Dupreez, Inorg. Chem. 33
(1994) 178.
[31] A.A. Soliman, G.G. Mohamed, Thermochim. Acta 421 (2004) 151.
[32] M.M.H. Khalil, M.M. Aboaly, R.M. Ramadan, Spectrochim. Acta 61A
(2005) 157.
[33] M.M.H. Khalil, A.A. Saadia, R.M. Ramadan, Spectrochim. Acta 57A
(2001) 1017.
[27] R.M. Ramadan, M.S.A. Hamza, S.A. Ali, J. Coord. Chem. 43 (1988)
31.
[34] H.A. Mohamed, A.A. Saadia, R.M. Ramadan, Spectrochim. Acta 64A
(2006) 913.
[28] K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination
Compounds, 4th ed., Wiley, New York, 1986.
[35] A.A. Abdel-Shafi, M.M.H. Khalil, H.H. Abdalla, R.M. Ramadan, Transi-
tion Met. Chem. 27 (2002) 69.