Synthesis and characterization of polymeric Pd(II), Pt(IV), and Au(III) complexes of 2,2′-(1,4-phenylenedivinylene)-bis-8-hydroxyquinoline

Article abstract of DOI:10.1134/S0036023606080080

The complexes of 2,2′-(1,4-Phenylenedivinylene)-bis-8- hydroxyquinoline (LH₂) with K₂PdCl₄, H ₂PtCl₆ and HAuCl₄ were synthesized and characterized with ¹H-and ¹³C-NMR, elemental analysis, FT-IR, and molar conductivity. Au(III) and Pt(IV) complexes have characteristic conductance, while the Pd(II) complex has a non-ionic structure according to the molar conductivity and elemental analysis. Pleiades Publishing, Inc. 2006.

Full text of DOI:10.1134/S0036023606080080

ISSN 0036-0236, Russian Journal of Inorganic Chemistry, 2006, Vol. 51, No. 8, pp. 1198–1201. © Pleiades Publishing, Inc., 2006.
COORDINATION
COMPOUNDS
Synthesis and Characterization
of Polymeric Pd(II), Pt(IV), and Au(III) Complexes
of 2,2'-(1,4-Phenylenedivinylene)-bis-8-Hydroxyquinoline1
a
b
a
b
Aydin Tavman , Mustafa Hayvali , Hayati Filik , and Emine Kiliç
a
Istanbul University, Faculty of Engineering, Department of Chemistry, 34320, Avcilar, Istanbul, Turkey
Ankara University, Faculty of Science, Department of Chemistry, Tandogan, 06100 Ankara, Turkey
b
e-mail: atavman@istanbul.edu.tr
Received December 7, 2005
Abstract—The complexes of 2,2'-(1,4-Phenylenedivinylene)-bis–8-hydroxyquinoline (LH2) with K2PdCl4,
H2PtCl6 and HAuCl4 were synthesized and characterized with 1H- and 13C-NMR, elemental analysis, FT-IR,
and molar conductivity. Au(III) and Pt(IV) complexes have characteristic conductance, while the Pd(II) com-
plex has a non-ionic structure according to the molar conductivity and elemental analysis.
DOI: 10.1134/S0036023606080080
1
INTRODUCTION
(LH2) (Fig. 1) in polymeric form have been synthesized
and characterized, and their light emitting properties in
organic electro-luminescence devices have been inves-
tigated [13]. New polyesters and polyurethanes have
been prepared utilizing LH2 as a starting material [14].
Filik et al. used LH2 in sequential spectrophotometric
determination of paracetamol and p-aminophenol [15].
8-Hydroxyquinoline (HQ) and its derivatives are
well-known bidentate ligands and polymer agents.
They have been widely used as metal chelating agents,
metal extracting agents, and corrosive inhibitors, and
they often show biological activity [1–5]. Metal com-
plexes of HQ derivatives have also been used as light
emitters. For example, tris-(HQ)-aluminum (Alq3) is
regarded as one of the best materials for this purpose in
view of its excellent electroluminescent properties [6–8].
Duann et al. synthesized tris-(7-substituted-HQ)-alu-
minum complexes and they found that the complexes
showed a red shift in emission wavelengths in different
solvents [9]. 5-Fluoro-HQ gave 1 : 3 M : L complexes
with Ga(NO3)3 as Alq3 [10].
The aim of this study is to synthesize and character-
ize the LH2 complexes with K2PdCl4, H2PtCl6, and
HAuCl4.
EXPERIMENTAL
All chemicals and solvents were reagent grade. IR
spectra were recorded on a Mattson 1000 Fourier
Bis-8-hydroxyquinoline derivatives have been the
subject of considerable interest from researchers since Transform spectrometer as KBr pellets. H and 13C
the first discovery of the tris(HQ)-aluminum complex (APT) NMR spectra were run on a Varian Unity Inova
by Tang et al. [6]. For example, 7,7'-di(N-substituted)- 500 NMR spectrometer in DMSO-d6; the signal was
1
5,5'-methylene-bis(HQ),
2,2'-(1,4-disubstituted)-
also used as an internal reference. Analytical data were
obtained with a Thermo Finnigan Flash EA 1112
microanalyzer. A Cary-1E UV-visible spectrophotome-
ter was used for the spectral measurements. The molar
bis(HQ), 5,5'-(N,N'-disubstituted)-bis(HQ), and some
of their polymeric zinc(II) and aluminum(III) com-
plexes have been synthesized and characterized, and
their fluorescence spectral properties have been investi-
gated in the literature [8]. In another study, some highly
alkyl-substituted bis-(HQ) derivatives were synthe-
sized and reacted with gallium(III) ions to form binu-
clear complexes [11]. Ethylene-bridged di-(HQ)
ligands were synthesized and reacted with gallium(III)
and zinc(II) to give metallacryptate complexes [12].
OH
N
N
HO
In the literature, Zn(II) and Al(III) complexes of
2,2'-(1,4-Phenylenedivinylene)-bis-8-hydroxyquinoline
Fig. 1. The structure of 2,2'-(1.4-Phenylenedivinylene)-bis-
1
This text was submitted by authors in English.
8-hydroxyquinoline (LH )
2
1198

SYNTHESIS AND CHARACTERIZATION
1199
conductance of the compounds was measured on a
WPA CMD750 conductivity meter.
Pt2(L)3Cl2. LH2 (62.5 mg, 0.150 mmol) was dis-
solved in absolute ethanol (50 ml), then H2PtCl6 · 6H2O
(52 mg, 0.10 mmol) was added to this solution. The
mixture was stirred at room temperature for 24 h. At the
end of this period, the brick-red-colored precipitate was
filtered, washed with ethanol (10 ml) and water (10 ml),
and dried at 80–90°C overnight.
Synthesis of the Ligand (LH2)
The ligand, LH2, was synthesized according to the
literature method [13]. Yield for yellow crystals: 83%;
mp 228°C. IR Spectra (KBr pellet) νmax/cm–1: 3395 m,
3053 m, 3026 m, 2930 w, 1632 m, 1624 sh, 1597 m,
1563 s, 1509 s, 1463 s, 1424 m, 1320 m, 1259 m,
1239 m, 1201 m, 1089 m, 967 s, 835 s, 746 s, 720 m,
584 m, 569 s. 1H NMR (δ, ppm; J, Hz): 9.60 (2H, s, br,
OH), 8.29 (2H, d, J = 8.8 Hz, H4), 8.18 (2H, d, J = 16.1,
H11), 7.80 (2H, s, br, H3), 7.78 (4H, s, H14 + H15),
7.55 (2H, d, J = 16.1, H12), 7.36–7.42 (4H, m, H5 +
H6), 7.13 (2H, d-d, J = 7.3 and 1.5, H7). 13C NMR
(APT, 125.68 MHz): δ 154.1 (C–O), 153.7 (C2), 138.9
(C9), 137.5 (C13), 137.2 (C4), 134.5 (C11), 129.1
(C6), 128.45 (C14 + C15), 128.4 (C10), 127.8 (C12),
121.8 (C5), 118.3 (C3), 111.9 (C7).
The yield for the dark orange compound
(C28H19N2O2)3Pt2Cl2 is ca. 95 mg (97.0%), m.p. 255–
265°C (dec.). Molar conductivity: 90 Ω–1 cm2 mol–1, in
DMSO, at 25 1°C. λmax = 429, 672, 762, 808 nm (in
DMSO). Elemental analysis, found: C, 49.11; H, 3.04;
N, 4.27; calcld.: C, 49.30; H, 2.79; N, 4.11. IR Spectra
(KBr pellet) νmax/cm–1: 3087 m, 3049 m, 1621 s,
1601 s, 1562 m, 1509 m, 1463 m, 1424 m, 1393 m,
1324 m, 1301 m, 1251 m, 1205 m, 1158 m, 1089 m,
969 m, 835 s, 746 m, 569 m. 1H NMR (δ, ppm; J, Hz):
8.47 (2H, s, br, H4), 8.21 (2H, d, J = 16.1, H11), 7.96
(2H, s, br, H3), 7.84 (4H, s, H14 + H15), 7.68 (2H, d,
J = 16.1, H12), 7.43–7.49 (4H, m, H5 + H6), 7.18 (2H,
d, J = 6.8, H7). 13C NMR (APT, 125.68 MHz): δ 153.8
(C–O), 152.8 (C2), 137.6 (C13), 130.2 (C6), 128.9
(C6), 128.7 (C14 + C15), 128.5 (C10), 128.3 (C12),
121.4 (C5), 118.5 (C3), 112.5 (C7).
OH
4
8'
14
3
7'
5
14'
13'
12'
10
12
9'
11'
13
15
N
2'
2
6
Au(L)Cl. LH2 (71 mg, 0.171 mmol) and HAuCl4 ·
3H2O (68 mg, 0.173 mmol) were used for synthesis.
The synthetic procedure is the same as that of
Pt2(L)3Cl2.
6'
11
N
9
10'
5'
7
3'
15'
8
4'
HO
The yield for C28H19AuClN2O2 is 107 mg (96.5%),
m.p. 315°C (dec.). Molar conductivity: 57 Ω–1 cm2 mol–1,
in DMSO, at 25 1°C. λmax = 448, 634, 746 nm (in
DMSO). Elemental analysis, found: C, 51.64; H, 3.18;
N, 4.19; calcd.: C, 51.86; H, 2.93; N, 4.32. IR Spectra
(KBr pellet) νmax/cm–1: 3080 m, br, 3049 m, 1621 s,
1594 s, 1532 m, 1497 m, 1463 m, 1420 m, 1389 s,
1324 m, 1297 m, 1250 m, 1208 m, 1158 m, 1089 m,
969 s, 843 s, 754 m, 577 m. 1H NMR (δ, ppm; J, Hz):
8.83 (2H, s, br, H4), 8.34 (2H, s, br, H3), 8.28 (2H, d,
J = 16.5, H11), 7.97 (2H, d, J = 16.2, H12), 7.87 (4H, s,
H14 + H15), 7.59–7.65 (4H, m, H5 + H6), 7.38 (2H, d,
br, J = 4.9, H7). 13C NMR (APT, 125.68 MHz): δ 154.9
(C−O), 152.9 (C2), 137.8 (C9), 136.4 (C13), 138.1
(C4), 136.1 (C11), 129.3 (C6), 128.8 (C14 + C15),
128.7 (C10), 127.0 (C12), 122.1 (C5), 118.9 (C3),
110.0 (C7).
Synthesis of the Complexes
Pd(L). KCl (30 mg, 0.40 mmol) and PdCl2 (33 mg,
0.18 mmol) were dissolved in 5 ml water. The obtained
solution of K2PdCl4 in water was added to LH2 (75 mg,
0.18 mmol) solution in 45 ml alcohol. The mixture was
stirred magnetically for approximately 24 h. The
brown–brick-red precipitate was filtered, washed in
alcohol (10 ml) and water (10 ml), and dried at 80–
90°C overnight.
K2PdCl4 + LH2
Pd(L) + 2KCl + 2HCl.
The yield for C28H19N2O2Pd is ca. 91.5 mg (97.5%),
m.p. > 350°C. Molar conductivity: 9.8 Ω–1 cm2 mol–1,
in DMSO, at 25 1°C. λmax = 371, 428, 567 nm (in
DMSO). Elemental analysis, found: C, 64.70; H, 3.82;
N, 5.07; calcld.: C, 64.38; H, 3.64; N, 5.36. IR Spectra
(KBr pellet) νmax/cm–1: 3076 m, 3053 m, 1620 s,
1597 s, 1555 s, 1505 m, 1443 s, 1378 m, 1328 m,
1286 m, 1205 m, 1108 m, 968 m, 831 m, 750 m, 550 m.
1H NMR (δ, ppm; J, Hz): 8.45 (2H, s, br, H4), 8.21 (2H,
d, J = 16.1, H11), 7.94 (2H, s, br, H3), 7.83 (4H, s,
H14 + H15), 7.66 (2H, d, J = 16.1, H12), 7.43–7.48
(4H, m, H5 + H6), 7.17 (2H, d, J = 6.8, H7). 13C NMR
(APT, 125.68 MHz): δ 153.8 (C–O), 130.3 (C6), 128.7
(C14 + C15), 128.5 (C10), 128.2 (C12), 121.5 (C5),
118.5 (C3).
RESULTS AND DISCUSSION
General Properties
LH2 is slightly soluble in alcohol and has moderate
solubility in strong solvents such as DMSO. The com-
plexes, however, are not soluble in polar solvents such
as alcohol and are only slightly soluble in DMSO and
DMF.
According to the molar conductivity values, the
Pd(L) complex has a nonionic character. The molar
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 51 No. 8 2006

1200
AYDIN TAVMAN et al.
2+
N
N
Cl–
Cl–
O
O
N
N
Pd
Au
O
O
Pd
Au
O
O
O
O
N
N
N
N
Fig. 2. The suggested structural formula for the polymeric Pd(II) and Au(III) complexes.
conductivity values of Pt(IV) and Au(III) complexes
Prominent peaks, which are the characteristic of the
are indicative of 1 : 1 and 1 : 2 electrolyte structures, absorption vibration of the aromatic ring skeleton, are
observed at 1563, 1509, 1463, and 1424 cm–1 in the
ligand.
respectively. Chlorine existing in Pt(IV) and Au(III)
complexes was tested with AgNO3.
The strong or medium bands between 831 and
Generally, the color of the complexes is darker and
more intense than the ligand. This observation shows 843 cm–1 are due to the out-of-plane deformation bands
that these complexes have light-emitting or dying prop- for the aromatic C–H in the quinoline part in the spectra
erties as in the Zn(II) and Al(III) complexes [13].
of the ligand and the complexes. The out-of-plane
deformation bands for the aromatic C–H in the bridged-
phenylene group appears around 750 cm–1 as a strong
band in the ligand and a medium band in the complex.
It is reported that the Zn(II) and Al(III) chelate com-
plexes of LH2 have polymeric structure [13]. The coor-
dination occurs through the phenolic oxygen and the
nitrogen atoms eliminating the phenolic hydrogen. The
C–O stretching vibrations of the ligand appear at
Zn(II) complex has a 1 : 1 M : L ratio, while the Al(III) 1239 cm–1 as a medium band. In the complexes, this
band shifts to lower frequencies (e.g., 1205 cm–1 in the
Pd(L) complex), and weakens.
complex has a 2 : 3 M : L ratio. Likewise, the Pd(II),
Pt(IV), and Au(III) complexes in the present study may
also be polymeric structures.
NMR Spectra
IR Spectra
The NMR spectra of the ligand and the complexes
are straightforward. However, the 13C-NMR spectra of
the complexes are not fine due to the low solubility of
the complexes in DMSO-d6.
In the IR spectra of the ligand, the broad bands
3400–2800 cm–1 show that there is intermolecular
hydrogen bonding between OH and C=N groups. These
bands disappear in the complexes. This observation is
the most characteristic evidence that coordination
occurs through the phenolic oxygen atom, and the OH
hydrogen atom is eliminated on complexation.
The chemical shift of hydrogen atoms at 3, 4, 7, and
8 positions that near the coordination region is higher
according to the other hydrogen atoms in the com-
plexes. The OH proton appears as a broad singlet at
9.60 ppm in the ligand, and disappears in the com-
plexes. This is evidence that the OH hydrogen atom is
eliminated because of the hydroxyl oxygen atom coor-
dination.
The peak between 3049 and 3053 cm–1 is attributed
to the stretching vibration of the C–H bond in the aro-
matic ring in the ligand and the complexes.
1
The bands at 1597, 1624, and 1632 cm–1 belong to
C=C and C=N stretching vibrations in the spectra of the
ligand. The band at 1632 cm–1 disappears in the com-
plexes. This shows that the band at 1632 cm–1 is due to
the C = N stretching vibration. The C=N system of the
In the H-NMR spectra of the ligand, H7 gives a
doublet of doublets because of interaction with H6 and
H5 protons. However, H5 and H6 show a complex pat-
tern. Proton H7 gives a broad doublet in the complexes
due to the increasing acidic character. Also, proton H4
has acidic character and shows a considerable shift on
complexation. H11 and H12 protons have a character-
istic coupling constant, J = 16.1 Hz.
In the 13C-NMR spectra of the Au(L)Cl complex, all
carbons are determined; however, in the Pd(L) and
Pt2(L)3Cl2 complexes, some carbon atoms cannot be
…
quinoline ring is changed to C—N
M when the
metal ion is bonded to the nitrogen atom, and conse-
quently, the C=N band disappears in the IR spectra. The
other bands, 1597 and 1624 cm–1, are assigned to the
aromatic and aliphatic –C=C– skeleton stretching
vibrations.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 51 No. 8 2006

SYNTHESIS AND CHARACTERIZATION
1201
4+
N
O
O
Pt
O
N
N
O
4Cl–
N
N
Pt
O
O
N
N
N
O
O
O
N
Pt
O
Pt
N
N
N
O
O
Fig. 3. The suggested structural formula for the polymeric Pt (L) Cl complex
2
3
2
3. K. Ohashi, S. Y. Choi, and J. Ougiyanagi, Bunseki
determined due to the low solubility of the complexes
in DMSO-d6.
Kagaku 49, 807 (2000).
4. E. R. Kenawy, J. Appl. Polym. Sci. 82, 1364 (2001).
5. R. Mladenova, M. Ignatova, N. Manolova, T. Petrova,
CONCLUSIONS
and I. Rashkov, Eur. Polym. J. 38, 989 (2002).
It is known that Pd(II) and Au(III) give four coordi-
nated complexes, tetrahedral or square-planar, and the
Pt(IV) ion prefers six coordinated geometric and octa-
hedral structures. In the present study, the Pd(L) and
Au(L)Cl complexes are structurally similar to the
Zn(II) complex of LH2, and the Pt2(L)3Cl2 complex is
similar to the Al(III) complex of LH2. However, a chlo-
ride ion in Au(L)Cl and two chloride ions in Pt2(L)3Cl2
stay out of the coordination sphere according to the
high molar conductivity and chloride test with AgNO3.
6. C. W. Tang and S. A. Vanslyke, Appl. Phys. Lett. 51, 913
(1987).
7. H. Li, F. Zhang, Y. Wang, and D. Zheng, Mat. Sci. Eng.
B 100, 40 (2003).
8. J. Xie, L. Fan, J. Su, and H. Tian, Dyes Pigments 59, 153
(2003).
9. Y. F. Duann, Y. J. Liao, W. Guo, and S. M. Chang, Appl.
Organometal. Chem. 17, 952 (2003).
10. O. Jarjayes, S. Hamman, M. C. Brochier, C. Beguin, and
R. Nardin, Magn. Reson. Chem. 38, 360 (2000).
In conclusion, considering the analytical data, molar
conductance values of the complexes, and by compar-
ing IR and NMR spectral data, the structure in Fig. 2 is
assigned to the polymeric complex of LH2 with Pd(L)
and Au(L)Cl, and that in Fig. 3 to the Pt2(L)3Cl2
complex.
11. M. Albrecht, O. Blau, and J. Zauner, Eur. J. Org. Chem.,
3165 (1999).
12. M. Albrecht, O. Blau, and R. Frohlich, Chem. Eur. J. 5,
48 (1999).
13. S. H. Kim, J. Z. Cui, J. Y. Park, J. H. Ryu, E. M. Han,
S. M. Park, S. H. Jin, K. Koh, and Y. S. Gal, Dyes Pig-
ments 55, 91 (2002).
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