Synthesis and characterization of novel oxime-imine ligands and their heteronuclear ruthenium(III) complexes

Article abstract of DOI:10.1134/S1070328409080065

Vicinal carbonyl oxime (HL¹) and oxime-imine (H ₂L²) ligands and their mononuclear Ru(III) and Cu(II), heterodinuclear Ru(III)-Mn(II), Ru(III)-Ni(II), Ru(III)-Cu(II), and heterotrinuclear Ru(III)-Cu(II)-Ru(III) chelates we

Full text of DOI:10.1134/S1070328409080065

ISSN 1070-3284, Russian Journal of Coordination Chemistry, 2009, Vol. 35, No. 8, pp. 588–596. © Pleiades Publishing, Ltd., 2009.
Synthesis and Characterization of Novel Oxime-Imine Ligands
and their Heteronuclear Ruthenium(III) Complexes1
F. Karipcin and G. Baskale-Akdogan
Süleyman Demirel University, Faculty of Sciences and Arts, Department of Chemistry, 32260 Isparta, Turkey
e-mail: karipcin@fef.sdu.edu.tr
Received October 17, 2008
Abstract—Vicinal carbonyl oxime (HL1) and oxime-imine (H2L2) ligands and their mononuclear Ru(III) and
Cu(II), heterodinuclear Ru(III)–Mn(II), Ru(III)–Ni(II), Ru(III)–Cu(II), and heterotrinuclear Ru(III)–Cu(II)–Ru(III)
chelates were synthesized and characterized by elemental analysis, molar conductivity, IR, ESR, ICP-OES, magnetic
moment measurements, and thermal analyses studies. The free ligands were also characterized by 1H NMR spectra.
The carbonyl-oxime ligand coordinates through the oxygen of =N–OH to form a six-membered chelate ring. The
quadridentate tetraaza ligand (H2L2) obtained by condensing of the bidentate ligand 1-p-diphenylmethane-2-hydrox-
yimino-2-(1-naphthylamino)-1-ethanone (HL1) with 1,2-phenylenediamine coordinates with Ru(III) through its ni-
trogen donors in the equatorial position with the loss of one of the oxime protons and concomitant formation of an
intramolecular hydrogen bond. Stoichiometric and spectral results of the metal complexes indicated that the metal :
ligand ratios in the mononuclear complexes of the ligand (HL1) were found to be 1 : 2, while these ratios were 1 : 1
in the mononuclear complexes of the ligand (H2L2). The metal : ligand ratios of the dinuclear complexes were found
to be 2 : 1, and this ratio was 3 : 2 in the trinuclear complex.
DOI: 10.1134/S1070328409080065
1
INTRODUCTION
have shown an exponential increase, as inorganic cata-
lytic processes, such as hydrogenation, isomerization,
decarbonylation, reductive elimination, oxidative addi-
tion, and C–C bond formation [16–21].
Oximes and Schiff bases are two important classes
of compounds owing to their wide applications in
industry, medicine, detection, and determination of var-
ious metal ions. These compounds have a number of
potential bonding sites, such as azomethine and imine
nitrogens and oxime oxygen. Therefore, Schiff bases
and oximes, as well as their coordination compounds,
have been studied extensively [1–8].
Ruthenium is well known for its ability to cover a
wide range of oxidation states (–2 to +8) and to adopt
various coordination geometries. Therefore, ruthenium
complexes exhibit versatile electron-transfer proper-
ties. A large number of ruthenium complexes have been
studied for their interesting and important properties,
such as artificial photosynthesis, photomolecular
devices, studies on biological macromolecules, cata-
lytic oxidation of water and organic substrates, and
organic synthesis. Because of such a broad range of
applications, there is a continuous interest to synthesize
new complexes of ruthenium with different types of
ligands [9–12].
In previous studies, we investigated the synthesis and
characterization of the mono- and trinuclear copper(II)
complexes of novel tetradentate Schiff bases [22, 23]. In
the present work, we report the synthesis and characteriza-
tion of the mononuclear Ru(III) (I) and Cu(II) (II) chelates
with the bidentate ligand, 1-p-diphenylmethane–2-hydrox-
yimino–2-(1-naphthylamino)–1-ethanone (HL1), mono-
nuclear Ru(III) (III), heterodinuclear Ru(III)–Mn(II) (IV),
Ru(III)–Ni(II) (V), Ru(III)–Cu(II) (VI), and heterotrinu-
clear Ru(III)–Cu(II)–Ru(III) (VII) chelates with the
quadridentate ligand, N,N'-o-bis[1-p-diphenylmethane–2-
hydroxyimino–2-(1-naphthylamino)–1-ethylidene]-phe-
nylenediamine (H2L2).
EXPERIMENTAL
Physical measurements. All solvents, 1-naphthy-
lamine and metal salts (RuCl3 · H2O, Cu(ClO4)2 · 6H2O,
Mn(OAc)2 · 4H2O, Ni(OAc)2 · 4H2O) used for the syn-
thesis and physical measurements were purchased from
Aldrich, J.T. Baker, and Merck and used as received.
1H NMR spectra of the ligands were recorded in CDCl3
solutions with TMS as internal standard at the NMR
Laboratory at Hacettepe University-Ankara-Turkey. IR
spectra (4000–400 cm–1) were recorded on a Shimadzu
The ruthenium complexes of diimine ligands is an
area of significant current interest, particularly with
regard to the photophysical and photochemical proper-
ties exhibited by such complexes [13–15]. Schiff base
and oxime complexes having O and N donor atoms
1
The article is published in the original.
588

SYNTHESIS AND CHARACTERIZATION OF NOVEL OXIME-IMINE LIGANDS
589
IRPrestige–21 FT-IR spectrophotometer as KBr pel- The X-band ESR spectra of the complexes were
lets. The thermogravimetric analysis (TG and DTG) of
the complexes were measured at the Central Laboratory
at METU-Ankara-Turkey. The C, H, and N contents
were determined microanalytically on a LECO 932
CHNS analyzer. The Ru, Mn, Ni, and Cu contents were
measured on a Perkin Elmer Optima 5300 DV ICP-
OES spectrometer. Magnetic susceptibilities were
determined on a Sherwood Scientific Magnetic Suscep-
recorded at room temperature on a Bruker Elexsys
E580 spectrometer. The conductance measurements
were carried out using an Optic Ivymen System con-
ductivity meter. Melting point determinations were per-
formed with a digital melting point instrument (Elec-
trothermal model IA 9100).
Synthesis of ligands HL1 and H2L2 was carried out
tibility Balance (Model MX1) at room temperature. in a few stÂs according following eqs:
O
O
AlCl
3
CH2
CH2
CH2
CH2
CH2Cl
+
(1)
(2)
Cl
CH2Cl
(DMK)
(HL)
O
O
NOH
RONO/HCl
CH2
CH2Cl
Cl
O
O
NOH
RH
NOH
(3)
CH2
Cl
R
(HL1)
R1
NH2
NH2
R1
2HL1 +
N
N
R
R
NOH
NOH
(H2L2)
R:
R1:
NH
CH2
(4)
At first 4-chloroacetyldiphenylmethane (DMK) was was filtered off and recrystallized from an ether–hexane
(1 : 1) mixture. The crystallized product was filtered,
washed with hexane, and dried over P2O5.
prepared according to the literature method [24] from
chloroacetylchloride and diphenylmethane in the pres-
ence of AlCl3 as catalyst in the Friedel-Crafts reaction
according Eq. (1). Then 1-p-diphenylmethane–2-
hydroxyimino–2-chloro–1-ethanone (HL) was pre-
pared according to previously published procedures
[22] according Eq. (2). DMK (2.45 g, 10 mmol) was
dissolved in 20 ml of chloroform with cooling, then
passing HCl gas into the solution for half an hour, and
then butyl nitrite (1.40 ml, 11 mmol) was added drop-
wise to the mixture with stirring and passing HCl gas
into the mixture. The mixture was left overnight at
The bidentate ligand HL1 was conveniently prepared
as reported in the literature [23] according Eq. (3). A
solution of 1-naphthylamine (2.86 g, 20 mmol) was
added dropwise to a solution of HL (10 mmol) in etha-
nol (20 ml) for 30 min at 0°C. The reaction mixture was
stirred for 2 h at the same temperature. Then it was
allowed to stir at ambient temperature for 2 h. The pow-
der resulting from the reaction is insoluble in ethanol
and, thus, was filtered off, washed with aqueous sodium
bicarbonate (1%), distilled water, and ethanol, and
room temperature to form a precipitate. The precipitate dried over P2O5.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 35 No. 8 2009

590
KARIPCIN, BASKALE-AKDOGAN
The quadridentate ligand H2L2 was conveniently 24 h. The product was filtered off, washed with H2O,
prepared as reported in the literature [23] according
Eq. (4). 1,2-Phenylenediamine (0.53 g, 5 mmol) and
HL1 (10 mmol) were mixed in absolute EtOH. The con-
tent was stirred magnetically at room temperature for 1
h. After the addition of distilled water to the reaction
mixture, the yellow powder product was seperated, col-
lected by filtration, washed several times with aqueous
sodium bicarbonate (1%), distilled water, and ethanol,
and dried over P2O5.
MeOH, and Et2O, and dried over P2O5.
Synthesis of binuclear
complex
[Ru(L2)Cl2Cu(Phen)]ClO4 (VI). The mononuclear
ruthenium complex III (1 mmol) was added to Et3N
(1mmol) in Me2CO (20 ml) and the mixture was stirred
for 0.5 h. Separated solutions of Cu(ClO4)2 · 6H2O
(370 mg, 1 mmol) in Me2CO (10 ml) and 1,10-phenan-
throline monohydrate (200 mg, 1 mmol) were succes-
sively added to the resulting mixture, which was boiled
under reflux for 3 h. The product was filtered off,
washed with H2O, MeOH, and Et2O, and dried over
P2O5.
Synthesis
of
mononuclear
complexes
[Ru(L1)2Cl(H2O)] (I) and [Ru(HL2)Cl2] (III) were car-
ried out as reported in similar literature [25]. A stoichi-
ometric amount of RuCl3 · H2O (10 mmol) in EtOH was
added to a hot solution of the desired ligand (20 mmol
in the case of HL1; 10 mmol in the case of H2L2) in abso-
lute EtOH, and the reaction mixture was boiled under
reflux with stirring for 2 h. On slow evaporation of
EtOH the desired complex was obtained as powder. In
some cases, complete precipitation was achieved by the
addition of Et2O to the cold reaction mixture. The
deeply colored precipitates were separated by filtration,
washed with cold EtOH followed by Et2O, and dried
over P2O5.
Synthesis of trinuclear complex [Ru2(L2)Cl4Cu]
(VII) was carried out as reported in similar literature
[23]. A mixture of III (1 mmol), Cu(ClO4)2 · 6H2O
(185 mg, 0.5 mmol), and Et3N (0.1 g, 1 mmol) in
Me2CO (20 ml) was refluxed for 2 h. The resulting solu-
tion was filtered while hot and concentrated slowly. As
the solution cooled, a black powder product precipi-
tated. It was isolated by filtration, washed with Et2O,
and dried in air.
Synthesis of mononuclear complex [Cu(L1)2(H2O)2]
(II) was carried out as reported in similar literature [25].
A stoichiometric amount of Cu(CH3COO)2 · H2O
(0.20 g, 1 mmol) in EtOH was added to a hot solution
of the bidentate ligand (2 mmol) in absolute EtOH, and
the reaction mixture was boiled under reflux with stir-
ring for 2 h. On slow evaporation of EtOH the desired
complex was obtained as powder. The deeply colored
precipitate was separated by filtration, washed with
cold EtOH followed by Et2O, and finally dried over
P2O5.
RESULTS AND DISCUSSION
As a result of conducted reactions we have gotten
the following complexes. The mononuclear Ru(III) and
Cu(II) complexes of HL1 [25]:
R1
X
R
N
2 O
C
C
O
O
C
C
M
Synthesis
of
binuclear
complex
[Ru(L2)Cl2Mn(Phen)2]ClO4 (IV) was carried out as
reported in similar literature [23]. The complex III
(1 mmol) was mixed with Et3N (1 mmol) in MeOH
(20 ml) and stirred for 0.5 h. Separated solutions of
Mn(OAc)2 · 4H2O (245 mg, 1 mmol) in MeOH (10 ml)
and 1,10-phenanthroline monohydrate (400 mg,
2 mmol) in MeOH (10 ml) were successively added to
the resulting solution. A stoichiometric amount of
NaClO4 · H2O (140 mg, 1 mmol) was then added to the
resulting mixture, which was boiled under reflux for
24 h. The product was filtered off, washed with H2O,
MeOH, and Et2O, and dried over P2O5.
O
X1
R1
N
R
where M = Ru(III), Cu(II); X1 = H2O, X2 = Cl in Ru(III)
complex and X1 = X2 = H2O in Cu(II) complex.
The mononuclear ruthenium(III) complex of H2L2
[23]:
R1
R
Synthesis
of
binuclear
complex
Cl
Ru
Cl
N
N O
[Ru(L2)Cl2Ni(Phen)2]ClO4 (V). The complex III
(1 mmol) was mixed with Et3N (1 mmol) in MeOH
(20 ml) and stirred for 0.5 h. Separated solutions of
Ni(OAc)2 · 4H2O (245 mg, 1 mmol) in MeOH (10 ml)
and 1,10-phenanthroline monohydrate (400 mg,
2 mmol) in MeOH (10 ml) were successively added to
the resulting solution. A stoichiometric amount of
NaClO4 · H2O (140 mg, 1 mmol) was then added to the
H
N
N O
R
R1
Heterodinuclear Ru(III)–Mn(II) and Ru(III)–Ni(II)
resulting mixture, which was boiled under reflux for complexes of H2L2 (M = Mn(II), Ni(II)) [23]:
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SYNTHESIS AND CHARACTERIZATION OF NOVEL OXIME-IMINE LIGANDS
591
tons in their expected regions, and these data are in
good agreement with those previously reported for sim-
ilar compounds [23, 26].
R1
N
R
N
The IR spectra of the free ligands and their com-
plexes represented in Table 3. The IR spectra of the
starting compounds HL and the ligands HL1, H2L2
showed medium-to-strong bands in the 3232–
3271 cm−1 range, assignable to ν(OH) of oxime groups;
the broad nature of these bands and their low wavenum-
bers suggested the presence of hydrogen bonding [27].
The spectrum of the ligands exhibited fairly strong
bands at 3369 (HL1) and 3379 (H2L2) cm–1 attributable
to the ν(NH) vibration of the aromatic amine groups.
The medium, sharp band at 1226 cm–1 was due to the
N–O stretching vibration [1, 2]. In the IR spectra of the
ligand H2L2, the stretching vibrations of C = Nimine and
C = Noxime were observed at 1635 and 1596 cm–1,
respectively. The band observed at 1596 cm–1 in ligand
HL1 also was assigned to the C=N groups. The C=O
vibrations for the compounds HL and HL1 were
observed as medium bands at 1655 and 1675 cm–1,
respectively. The spectrum of the ligand H2L2 did not
show absorption characteristic of the C=O function
owing to the formation of the imine [1, 2].
Cl
Ru
Cl
N O
N
N
ClO4
M
N
N
N O
R
R1
Heterodinuclear Ru(III)–Cu(II) complex of H2L2
[23]:
R1
R
Cl
Ru
Cl
N
N
N
N O
ClO4
Cu
N
N O
R
R1
The characteristic absorption bands of the ligands
HL1, H2L2 were shifted on complex formation, and new
vibrational bands characteristic of the complex
appeared. The broad stretching bands due to the –OH
groups of the free ligands did not appear in the IR spec-
tra of the complexes (except for the mononuclear ruthe-
nium complex III) indicating the deprotonation of the
–OH groups and the formation of M–O bonds. This was
supported by the appearance of a new band in the
region 507–581 cm–1 assigned to ν(M–O) [1, 2]. In the
IR spectrum of the complex III a broad weak band was
observed at 1766 cm–1 due to O–H···O intramolecular
hydrogen bonds [1, 2].
Heterotrinuclear Ru(III)–Cu(II)–Ru(III) complex of
H2L2 [23]:
R1
R
R
R1
Cl
Ru
Cl
Cl
Ru
Cl
N
N O
O N
N
Cu
N
O N
R
N O
R
N
R1
R1
Except for the heteronuclear Ru–Mn (IV) and Ru–
Ni (V) complexes, all of the complexes showed a broad
band in the 3436–3447 cm–1 region, which confirms the
presence of water molecules hydrated to the metal ion
[6]. In the spectrum of the heteronuclear Ru–Cu com-
plex (VII), a broad band is in the 3236 cm–1, indicating
that the complex has coordination water. In the com-
plexes I, II, C=O group bands became extinct, indicat-
ing coordination through the C=O group. Vibrational
evidence for the coordination of the oximato group in
the complexes is provided by the higher frequency band
of N–O at ~1266–1296 cm–1 [3]. The appearance of a
new band at 419–433 cm–1 was assigned to ν(M–N)
[6, 28].
The powdered complexes are soluble in DMF and
DMSO and slightly soluble in chloroform and acetone.
The resulting solids are intensely colored, and stable in
air. Attempts to isolate crystals suitable for X-ray dif-
fraction were unsuccessful. Therefore, elemental anal-
ysis, spectroscopic tecniques, conductivity, thermal and
magnetic susceptibility techniques were employed in
order to determine the structural characteristics of the
complexes. The analytical and physical data for the
ligands and their complexes are given in Table 1.
The 1H NMR spectra of the starting compounds HL
and the ligands HL1, H2L2 exhibited a broad singlet
peak at 8.85 and 8.11 ppm for the OH protons of the
oxime groups. The chemical shifts in a region of
7.10−8.10 ppm were assigned to hydrogen of the aro-
The binuclear complexes IV–VI have a medium
matic ring. Furthermore, the singlets in a range of 3.99– band in a region of 1108–1123 cm–1 and a weak band at
4.20 ppm were assigned to protons of the methylene the 1019–1020 cm–1 range, featuring typical characteris-
groups of the diphenylmethane. The other obtained val- tics of uncoordinated perchlorates [1, 2]. Thus, the IR
1
ues for H NMR chemical shifts of these compounds spectra of the ligands and their metal complexes give
are given in Table 2. The total number of protons strong evidence for the complexation of the potentially
present in the compounds exhibited signals of the pro- multidentate ligands.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 35 No. 8 2009

592
KARIPCIN, BASKALE-AKDOGAN
Table 1. Elemental analysis data and some physical properties of the ligands and their complexes
Content (found/calcd), %
Cu, Ni,
µeff,
Λm,
M. p., Yield,
Compound
Color
µB
Ohm–1 cm2 mol–1 °C
%
C
H
N
Ru
or Mn
[C15H13OCl] (DMK)
[C15H12NO2Cl] (HL)
[C25H20N2O2] (HL1)
[C50H40N4O5ClRu] (I)
[C50H42N4O6Cu] (II)
Light
55
108
148
27
79
95
26
34
73.21/ 5.07/
73.62 5.35
65.34/ 4.18/ 4.99/
65.82 4.42 5.12
78.76/ 5.03/ 7.25/
78.93 5.29 7.36
65.37/ 4.14/ 6.02/
65.75 4.41 6.13
69.57/ 4.58/ 6.51/
69.96 4.93 6.53
yellow
Yellow
Light
yellow
1.62 Black
32
18
247
205
10.84/
11.07
1.23 Dark
brown
7.11/
7.40
(Cu)
[C56H44N6O2] H2L2
Light
yellow
1.70 Black
170
38
76
61
80.39/ 5.26/ 9.70/
80.75 5.32 10.09
64.55/ 4.17/ 7.87/
64.67 4.56 8.08
63.07/ 3.52/ 8.88/
63.31 3.85 9.23
[C56H47N6O4Cl2Ru] (III)
21
86
225
9.54/
9.72
6.24/
6.66
[C80H58N10O6Cl3RuMn] (IV) 4.14 Black
195*
3.29/
3.62
(Mn)
[C80H58N10O6Cl3RuNi] (V)
[C68H54N8O8Cl3RuCu] (VI)
2.23 Black
1.26 Black
78
92
23
225*
245
55
88
40
62.76/ 3.65/ 8.92/
63.15 3.84 9.21
3.22/
3.86
(Ni)
4.26/
4.60
(Cu)
2.96/
3.02
(Cu)
6.31/
6.64
58.82/ 3.51/ 7.93/
59.09 3.93 8.11
7.08/
7.31
[C112H88N12O6Cl4Ru2Cu] (VII) 0.97 Black
250*
63.87/ 3.79/ 7.86/
63.89 4.21 7.98
9.27/
9.60
* Decomposition point.
1
Table 2. H NMR data (ppm) of the starting compounds and the ligands
Compound
OHoxime
C–Harom
N–H
–CHDFM
–CHaliph
DMK
HL
HL1
H2L2
7.90–7.10 (m., 9H)
8.10–7.10 (m., 9H)
7.99–7.20 (m., 16H)
7.98–7.11 (m., 36H)
4.00 (s., 2H)
4.20 (s., 2H)
3.99 (s., 1H)
3.99 (s., 2H)
4.50 (s., 2H)
8.85 (s., 1H)
8.11 (s., 1H)
8.11 (s., 2H)
6.96 (s., 1H)
6.96 (s., 2H)
The molar conductance of the complexes was an aid
The room temperature magnetic moments of the
for proposing their formulas. Conductivity measure- complexes showed that all of the complexes are para-
ments were carried out in 10–3 mol dm–3 N,N-dimethyl- magnetic (Table 1). The measured magnetic moments
formamide solutions at 20°C. The binuclear complexes of the mononuclear ruthenium(III) complexes are 1.62
IV–VI exhibited various conductances between the 78– and 1.70 µB for I and III, respectively. Magnetic sus-
92 Ohm–1 cm2 mol–1 range, and other complexes (I, II, ceptibility measurements showed that these complexes
III, VII) exhibited conductances between the 18– are one-electron paramagnetics (µeff = 1.62–1.70 µB),
32 Ohm–1 cm2 mol–1 range (Table 1). The molar con- which corresponds to the +3 oxidation state of ruthe-
ductances of the binuclear complexes IV–VI in DMF nium (low-spin d5, S = 1/2) in these complexes [1, 2].
indicated that these complexes contain perchlorate ions The magnetic moment of the mononuclear copper(II)
behave as 1 : 1 electrolytes [1, 2]. However, the other complex II is 1.23 µB and the magnetic moment of tri-
complexes (I, II, III, VII) are non electrolytes [27].
nuclear Ru(III)–Cu(II)–Ru(III) complex is 0.97 µB. The
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 35 No. 8 2009

SYNTHESIS AND CHARACTERIZATION OF NOVEL OXIME-IMINE LIGANDS
Table 3. IR spectra of the ligands and their metal complexes
593
ν, cm–1
C–N (NO)
Compound
ClO–4
N–H
(OH)
C=O
C=N
M–N
M–O
Ru–N
HL
HL1
I
3232 s
1655 s
1675 s
1601 s
1596 s
1601 s
1290 s
3379 m 3271 b
1404 m 1226 s
1399 m 1276 m
3310 b
3360 b
3369 s
3436 b
3447 b
3271 m
581 w
517 w
700 m
II
H2L2
1650 w 1601 w 1394 m 1271 w
1596 s
1404 m 1226 s
1635 m
III
IV
V
3320 b
3367 b
3330 b
3320 b
3320 b
3261 b
1766 b
1601 s
1399 w 1275 w
670 s
670 s
700 m
670 w
670 w
1601 m 1399 w 1295 m 1123 m
1019 w
419 m
433 w
428 w
424 w
517 m
512 w
507 w
513 m
1601 s
1621 w
1394 w 1275 w 1108 m
1019 w
VI
VII
3447 b
3236 b
1597 s
1394 w 1296 m 1123 m
1020 w
1601 s
1394 w 1266 m
magnetic moments of the dinuclear complexes are 4.14,
2.23, and 1.26 µB for IV, V and VI, respectively. It can
be observed that these magnetic moment values of the
ruthenium(III) complexes are slightly lower than those
expected for the binuclear ruthenium(III) complexes
and the theoretical value of 1.73 µB for one low-spin d5
ruthenium ion. The strong antiferromagnetic coupling
that was found for bi (IV–VI) and trinuclear ruthe-
nium(III) (VII) complexes is explained as the oximato
group have good superexchange properties [29]. These
abnormal magnetic moment values of the binuclear
complexes may be explained by the weak antiferro-
magnetic intramolecular interaction, since this situation
can occur when two equivalent metal ions are coupled
via an exchange interaction in a polynuclear complex
[26, 30].
The thermal behavior of all the complexes was
almost the same. In thermogravimetry (TG) the change
in weight of a complex was recorded as a function of
temperature during heating. The TG curve was also
supported by the derivative thermogravimetry (DTG)
curves.
It is noted from the TG analysis that the mononu-
clear Ru(III) complex (I) of HL1 lost 85.90% (calcu-
lated mass loss = 86.31%) of its original mass between
185 and 535°C and the residue was Ru2O3. The sample
decomposed in three stages. The first decomposition
occurred between 185 and 288°C with 6.10% estimated
mass loss (calculated mass loss = 5.85%), the second
and third decompositions occurred between 288 and
535°C with 79.80% estimated mass loss (calculated
mass loss = 80.46%) corresponding to the loss of the
ligand molecules.
The room temperature solid-state EPR spectrum of
the mononuclear Ru(III) complex (III) was recorded at
X-band frequencies. The low-spin d5 configuration is a
good probe of molecular structure and bonding, since
the observed g values are very sensitive to small
changes in structure and to the metal-ligand covalency.
The EPR spectra of the complexes exhibit a character-
istic of an axially symmetric system with g⊥ of 2.599
and g|| of 1.998. The presence of two different g values
(gx = gy ≠ gz) indicates an octahedral field with tetrago-
nal or square pyramidal distortion. Overally, the posi-
tion of lines and nature of the EPR spectra of the com-
plexes are characteristic of low-spin ruthenium(III)
octahedral complexes [31].
The mononuclear Cu(II) complex (II) of HL1
showed the decomposition pattern of five stages. The
first four steps with an estimated mass loss of 37.50%
(calculated mass loss = 37.46%) were found within the
temperature range 115–550°C corresponding to the loss
of two H2O molecules and 1-naphthylamine molecule.
The last stage did not finish completely at 900°C.
The ligand H2L2 showed a decomposition pattern of
four stages. The first three stages with an estimated
mass loss of 38.40% (calculated mass loss = 38.22%)
were found within the temperature range 120–340°C
corresponding to the loss of one OH and 1-naphthy-
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594
KARIPCIN, BASKALE-AKDOGAN
Table 4. Thermoanalytical results (TG, DTG) of the metal complexes
Estimated (calcd), %
Compound TG range, °C DTGmax, °C
Assignment
Metallic residue
Ru2O3/2
mass loss
total mass loss
I
185–288
288–535
115–550
249
6.10
(5.85)
Loss of one Cl and one H2O
molecule
400, 495
79.80
85.90
Loss of ligand molecules
(80.46)
(86.31)
II
220, 330, 360,
410
37.50
(37.46)
Loss of two H2O and 1-
naphthylamine molecules
550–900
120–340
590
Loss of the other groups
Decomposition
is in progress
H2L2
160, 210, 280
38.40
(38.22)
Loss of 1-naphthylamine
and OH molecules
340–900
35–102
460
69
Loss of the other groups
Decomposition
is in progress
III
2.95
Loss of two H2O molecules
(3.46)
102–280
280–635
50–515
235
412
390
7.10
(6.78)
Loss of two Cl atom
77.40
(77.74)
87.45
(87.98)
Loss of ligand molecules
Ru2O3/2
IV
V
43.40
(44.01)
Loss of ClO4, two Cl, two
phenanthroline and diphe-
nylmethane molecules
515–900
50–555
560
310
Loss of the other groups
Decomposition
is in progress
33.40
(33.05)
Loss of ClO4, two Cl and
two phenanthroline mole-
cules
555–900
40–120
635
65
Loss of the other groups
Decomposition
is in progress
VI
2.40
Loss of two H2O molecules
(2.61)
120–350
350–560
560–945
35–110
245
12.60
(12.63)
Loss of ClO4 and two Cl at-
oms
487
13.10
(13.04)
Loss of phenanthroline mol-
ecule
687
24.50
(24.20)
52.60
(52.48)
Loss of diphenylmethane
molecules
Decomposition
is in progress
VII
60
2.10
Loss of two H2O molecules
(1.71)
110–675
675–980
290, 450, 620
772
39.00
(38.51)
Loss of four Cl and diphe-
nylmethane molecules
Loss of the other groups
Decomposition
is in progress
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SYNTHESIS AND CHARACTERIZATION OF NOVEL OXIME-IMINE LIGANDS
595
lamine molecules. The last stage did not finish com-
The theoretical and experimental percent mass
losses obtained from these decomposition stages are in
good agreement. The critical data and values deduced
from the present study are summarized in Table 4.
pletely at 900°C.
It was found from TG analysis that the mononuclear
Ru(III) complex (III) of H2L2 starts losing mass at 35°C
and ends at 635°C after losing 87.45% (calculated mass
loss = 87.98%) of its mass with a Ru2O3 residue which
corresponds to 12.65% of the total mass. The examina-
tion of the TG curve showed that the complex decom-
poses in three stages. The sample lost 2.95% of mass
between 35 and 102°C, 7.10% of the mass between 102
and 280°C, and 77.40% between 280 and 635°C. These
decomposition stages corresponded to the loss of two
H2O molecules, two Cl atoms, and ligand molecules
and calculated mass losses were 3.46, 6.78, and 77.74,
respectively.
The binuclear Ru(III)–Mn(II) complex (IV) exhib-
ited the first mass loss in the temperature range 50–
515°C with a maximum at 390°C in the DTG curve. It
may be attributed to the liberation of ClO4, two Cl, two
phenanthroline and diphenylmethane molecules. The
second mass loss at 515–900°C with a maximum at
560°C was due to the liberation of the other groups.
However, the decomposition did not finish at 900°C
completely.
The binuclear Ru(III)–Ni(II) complex (V) decom-
posed in two stages. In the first stage the estimated mass
loss was 33.40% (calculated mass loss = 33.05%). The
temperature range of this decomposition was found to
be 50–555°C corresponding to the loss of ClO4, two Cl,
and two phenanthroline molecules. The second stage
did not finish completely at 1000°C.
The binuclear Ru(III)–Cu(II) complex (VI) showed
the decomposition pattern of four stages. The first stage
with an estimated mass loss of 2.40% (calculated mass
loss = 2.61%) was found within the temperature range
40–120°C corresponding to the loss of two H2O mole-
cules. The second stage with an estimated mass loss of
12.60% (calculated mass loss = 12.63%) was found
within the temperature range 120–350°C and the third
stage with an estimated mass loss of 13.10% (calcu-
lated mass loss = 13.04%) was found within the tem-
perature range 350–560°C corresponding to the loss of
perchlorate, two Cl, and phenanthroline groups. The
last stage with an estimated mass loss of 24.50% (cal-
culated mass loss = 24.20%) was found within the tem-
perature range 565–945°C corresponding to the loss of
diphenylmethane groups.
ACKNOWLEDGMENTS
This study was supported by The Scientific and
Technical Research Council of Turkey (TUBITAK),
project no. TBAG-HD/223 (106T723) (Ankara, Tur-
key) and the Research Fund of Suleyman Demirel Uni-
versity, project no. 1270-YL–04 (Isparta, Turkey).
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