Synthesis and spectral characterization of some complexes of platinum(II) containing η2-methyleugenol

Article abstract of DOI:10.1016/j.poly.2007.03.017

Several complexes of the formula trans-[Pt(Meug)(Am)Cl₂], Meug: methyleugenol (4-allyl-1,2-dimethoxybenzene), a η²-coordinated olefin, and Am: ammine, methylamine, diethylamine, o-toluidine, m-toluidine, p-toluidine, o-anisidine, m-anisidine and p-anisidine have been prepared. UV, IR, Raman, ¹H NMR, ¹³C NMR and 2D NMR spectra of the complexes were recorded and analyzed.

Full text of DOI:10.1016/j.poly.2007.03.017

Polyhedron 26 (2007) 3271–3276
www.elsevier.com/locate/poly
Synthesis and spectral characterization of some complexes
of platinum(II) containing g2-methyleugenol
*
Tran Thi Da, Nguyen Thi Tuyet Minh, Nguyen Thi Thanh Chi, Nguyen Huu Dinh
Department of Chemistry, Hanoi National Pedagogic University, Hanoi, Vietnam
Received 7 February 2007; accepted 3 March 2007
Available online 21 March 2007
Abstract
Several complexes of the formula trans-[Pt(Meug)(Am)Cl2], Meug: methyleugenol (4-allyl-1,2-dimethoxybenzene), a g2-coordinated
olefin, and Am: ammine, methylamine, diethylamine, o-toluidine, m-toluidine, p-toluidine, o-anisidine, m-anisidine and p-anisidine have
1
been prepared. UV, IR, Raman, H NMR, 13C NMR and 2D NMR spectra of the complexes were recorded and analyzed.
Ó 2007 Elsevier Ltd. All rights reserved.
Keywords: Platinum complexes; Olefin complexes; Methyleugenol; 1H NMR; 13C NMR
Methyleugenol
1. Introduction
K½PtðC H ÞCl ꢀ
K½PtðMeugÞCl ꢀ
ƒƒƒƒƒƒƒ!
2
4
3
3
ð1Þ
Platinum–olefin complexes quite long ago attracted the
attention of chemists [1,2]. Various olefin ligands have been
used. Amongst the arylolefin ligands, phenylethylene (sty-
rene) and substituted phenylethylenes were widely studied
[3,4], but phenylpropylenes were rare. Today substituted
phenylpropylenes, which are easily available from natural
resources, have been used as valuable starting materials
in various synthetic processes [5]. In many cases transition
metals-olefin complexes are present as key intermediates.
Eugenol, izoeugenol and methyleugenol (4-allyl-1,2-
dimethoxybenzene) represents interesting phenylpropyl-
enes, extracted from essential clove oil, which can be
transformed into coniferyl aldehyde, coniferyl alcohol,
vanilin and vanillic acid, compounds commonly used in
the flavour and fragrance industry [6]. In this paper we
describe some platinum(II) complexes containing methyl-
eugenol, which are prepared as follows:
Amine
trans-½PtðMeugÞðAmÞCl ꢀ
ƒƒƒ!
2
ð2Þ–ð10Þ
Meug: Methyleugenol (4-allyl-1,2-dimethoxybenzene,
formula I).
Am: NH3 (2), CH3NH2 (3), (C2H5)2NH (4), o-CH3-
C6H4NH2 (5), m-CH3C6H4NH2 (6), p-CH3C6H4-
NH2 (7), o-CH3OC6H4NH2 (8), m-CH3OC6H4NH2 (9),
p-CH3OC6H4NH2 (10).
2. Results and discussion
The complexes [Pt(Meug)(Am)Cl2] were prepared by
replacement of a Cl ligand from K[Pt(Meug)Cl3] (1) by
an amine, Am. According to the trans-effect, the Cl ligand
in the opposite position to Meug is replaced by the amine.
For volatile amines such as methylamine, diethylamine and
NH3, the reaction was carried out at 10–15 °C, with
1.2 mmol of amine per 1 mmol of 1. For toluidines and
anisidines, the reaction was carried out at 25–30 °C, with
1.1 mmol of amine per 1 mmol of 1. The neutral complexes
[Pt(Meug)(Am)Cl2] precipitate out and can be easily
*
Corresponding author. Tel.: +84 4 8 346 632.
E-mail address: nguyenhuudinh1954@yahoo.com (N.H. Dinh).
0277-5387/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2007.03.017

3272
T.T. Da et al. / Polyhedron 26 (2007) 3271–3276
isolated, then purified by recrystallizing from aqueous
EtOH solution.
(6.98 ppm) show signals of C-11 (130.52), C-15 (121.81).
Two cross peaks g, h of H-5 (6.96 ppm) show signals of
C-1 (148.83), C-3 (113.88). Two cross peaks i, k of H-6
(6.86 ppm) show signals of C-2 (150.11), C-4 (132.3).
Two cross peaks l, m of H-15 (6.88 ppm) show signals of
C-11 (130.52), C-13 (112.88). The cross peaks of C-12, C-
2 and C-1, in turn, allow one to distinguish the signals of
H-17, H-7b and H-7a.
The molar conductivity (l) of 10ꢁ4 M K[Pt(Meug)Cl3]
solution is 95 Xꢁ1 cm2 molꢁ1. The molar conductivity (l)
of a 5.10ꢁ5 ꢁ 10ꢁ4 M solution of trans-[Pt(Meug)(Am)Cl2]
is in the range 15–22 Xꢁ1 cm2 molꢁ1, indicating its non-
electrolytic nature (Table 1).
The electronic spectra of the synthesized complexes are
given in Table 1. All the examined complexes are slight
soluble. Their spectra were recorded at a concentration
as small as 10ꢁ4 M in 96% by volume aqueous EtOH.
Thus only charge-transfer and ligand spectra were
obtained.
In Table 1, the m(Pt–N), m(Pt–Cl) values were taken from
the Raman spectra. Because the intensity of m(NH) in the
Raman spectra was too weak, the m(NH) value was taken
from the IR spectra. These values are in general agreement
with those in the literature [1,7].
Upon coordination to Pt(II), the resonances of the
ethylenic protons (H-9, H-10 cis and H-10 trans, Table
2) are upfield in comparison to those of non-coordinated
methyleugenol (5.86, 4.96 and 4.98 ppm, respectively).
The 195Pt satellites in the signals from H-9 are broadened
beyond detection, but two satellites in the signals from
2
H-10 cis and H-10 trans are clear, with a JPtH value
of 60–70 Hz (Table 2). The resonances of the ethylenic
carbons (C-9, C-10) are upfield too (Table 4). These indi-
cate that methyleugenol is present as an g2-coordinated
olefin.
The NMR data of the examined compounds are pre-
sented in Tables 2–4. The numeration of the examined
compounds for the analysis of the NMR spectra is as
follows:
For non-coordinatinated methyleugenol, two protons
H-8 (formula I) give rise to a doublet at 3.22 ppm with
3J = 6.5 Hz, but in the spectra of the examined com-
plexes we usually observed one doublet of doublets cen-
tered at 3.38–3.55 ppm for H-8a and another doublet of
doublets centered at 3.01–3.21 ppm for H-8b. This is
expected since upon coordination to Pt(II), atom C-9
becomes a chiral center, and H-8a and H-8b become
diastereotopic.
5
12
6
R17
7a
CH3O
8
CH3NH2
1
12
11
13
14
15
4
CH2
9 10
(II)
12
trans
cis
H
NH2
2
C
C
7b
3
13
H
16
H
CH3O
(CH3CH2)2NH
(IV)
(I, Meug)
(III)
1
It is interesting that in H NMR and 13C NMR spectra
of trans-[Pt(Meug)(Et2NH)Cl2] (4), recorded in d6-acetone,
two CH2 groups of diethylamine give rise to two compli-
cated proton signals (one multiplet centered at 2.88 ppm
and another at 3.17 ppm, H12a and H12b in Fig. 2) and
two 13C signals at 49.67 and 49.69 ppm; two CH3 groups
give rise to two triplets (one centered at 1.400 and another
at 1.395 ppm) and the two 13C signals are at 14.67 and
14.74 ppm. This anomaly also happens in the spectra of 4
recorded in CD3CN. It is noted that we have just prepared
trans-[Pt(Saf)(Et2NH)Cl2] (4a) and trans-[Pt(Saf)(Me2-
NH)Cl2] (4b) (Saf: 4-allyl-1,2-methylendioxybenzene, Et:
–CH2CH3, Me: CH3). In the spectra of 4a recorded in
d6-acetone, two CH2 groups of diethylamine give rise to
two complicated proton signals (one multiplet centered at
The assignment of the NMR signals is based on their
chemical shift, spin-spin splitting patterns, HMQC, HMBC
and NOESY spectra. For example, the assignment of some
ambiguous signals from the 13C NMR spectrum of com-
plex 8 and then the signals of H7a, H7b, H17 have been
assigned as illustrated in Fig. 1.
In Fig. 1, the signals of all the protons, except H-7a, H-
7b and H-17, have been unambiguously assigned, the sig-
nals of ring carbons are thus identified. Two cross peaks
a and b of H-16 (7.29 ppm) show that two signals at
152.0 and 127.0 ppm belong to C-12 and C-14, respectively.
Two cross peaks c, d of H-14 (7.15 ppm) show signals of C-
12 (152.0), C-16 (124.1). Two cross peaks e, f of H-13
Table 1
Molar conductivity (l), the main bands in UV-, IR- and Raman spectra of the synthesized complexes
Compound
l, Xꢁ1 cm2 molꢁ1
kmax (nm)/loge
m (NH) (IR, cmꢁ1
)
m (Pt–N) (Raman cmꢁ1
)
m (Pt–Cl) (Raman cmꢁ1
)
1
2
95
22
21
20
15
18
16
19
17
18
231/4.25; 284/3.38; 341/3.37
240/3.98; 280/3.82
230/3.78; 279/3.17
231/4.03; 279/3.90
232/4.16; 276/3.86
232/4.06; 279/3.75
230/4.27; 274/4.00
233/4.25; 283/3.96
230/3.78; 281/3.27
225/4.43; 279/4.16
330
335
336
334
333
332
340
331
338
340
3274, 3191
3270, 3221
3224
3225, 3203
3302, 3225
3282, 3220
3248, 3213
3283, 3233
3293, 3229
525
525
492
485
470
489
489
485
502
3
4
5
6
7
8
9
10

T.T. Da et al. / Polyhedron 26 (2007) 3271–3276
3273
Table 2
The resonances of protons H-3 to H-9 of the examined complexes, d (ppm), J (Hz)
Compound (solvent)
H-3
H-5
H-6
H-7a
H-7b
H-8a
H-8b
H-9
1
7.36 d
4J 1.5
6.87 s
6.93 dd
6.91 d
3J 8
6.84 d
3J 8
6.84 d
3J 8
6.90 d
3J 8
6.88 d
3J 8.5
6.77 d
3J 8
6.78 d
3J 8
6.86 d
3J 8
6.81 d
3J 8.5
6.80 d
3J 8
3.87 s
3.89 s
2.90 dd
3.49 dd
5.21 m
5.60 m
5.59 m
5.45 m
5.53 m
5.40 m
5.39 m
5.44 m
5.42 m
5.38 m
a
a
(CD3OD)
2
3J 8, 4J 1.5
6.89 dd
2J 15, 3J 6.5
3.21 dd
2J 15, 3J 7
3.55 dd
3.89 s
3.89 s
3.83 s
3.78 s
3.78 s
3.79 s
3.80 s
3.79 s
3.79 s
3.87 s
3.87 s
3.78 s
3.76 s
3.75 s
3.75 s
3.76 s
3.78 s
3.75 s
(CDCl3)
3
3J 8, 4J 1.5
6.89 dd
2J 15, 3J 8
3.21 dd
2J 15, 3J 6
3.52 dd
6.87 d
4J 1.5
7.02 d
4J 2
(CDCl3)
4
3J 8, 4J 1.5
6.92 dd
2J 15, 3J 7.5
3.19 dd
2J 15, 3J 6.5
3.43 dd
(CD3COCD3)
5
3J 8, 4J 2
6.92 dd
2J 15, 3J 7.5
3.09 dd
2J 15, 3J 6.5
3.42 dd
6.97 s
(CD3COCD3)
6
3J 8.5, 4J 1.5
6.95 dd
2J 15, 3J 6
3.01 dd
2J 15, 3J 7.5
3.39 dd
6.99 d
4J 2
6.97 s
4J 2
7.00 d
4J 1.5
7.03 d
4J 2
7.01 d
4J 2
(CD3CN)
7
3J 8, 4J 2
6.94 dd
2J 15, 3J 6.5
3.01 dd
2J 15, 3J 8
3.38 dd
(CD3COCD3)
8
3J 8, 4J 2
6.96 dd
2J 15, 3J 6
3.03 dd
2J 15, 3J 8
3.40 dd
(CD3CN)
9
3J 8, 4J 1.5
6.92 dd
2J 15, 3J 6
3.08 dd
2J 15, 3J 7.5
3.45 dd
(CD3COCD3)
10
3J 8.5, 4J 2
6.95 dd
2J 15, 3J 6.5
3.06 dd
2J 15, 3J 7.5
3.41 dd
(CD3COCD3)
3J 8, 4J 2
2J 15, 3J 6.5
2J 15, 3J 7.5
a
Because of methanol.
Table 3
The resonances of protons H-10 to H-17 of the examined complexes, d (ppm), J (Hz)
Compounda
H-10 cis
H-10 trans
H-12
H-13
H-14
H-15
H-16
Others
1
4.30 d
4.46 d
(a)
2
3J 7.5, JPtH 70
4.62 dd, 2J 1,
3J 8, JPtH 65
4.56 dd,2J 1,
3J 7.5, JPtH 70
4.40 dd, 2J 1.5,
3J 8, JPtH 68
4.44 d
3J 7.5, JPtH 70
4.69 dd, 2J 1,
3J 14, JPtH65
4.69 dd,2J 1,
3J 14, JPtH 70
4.53 dd, 2J 1.5
3J 14, JPtH 64
4.54 d
3.55 s: NH3
3.85 s: NH2
5.28 s: NH
(b)
3
2.66 t,
3J 6.5
3.17 m,
2.88 m
(b)
4
1.400 t,
1.395 t
(c)
5
7.13 dd
3J 6.5, 4J 2
7.08 td
3J 7, 4J 2
7.03 d
3J 7.5
7.07 td
3J 7, 4J 2
7.19 t
3J 7.5
7.24 dd
3J 7, 4J 2
7.06 d
3J 8
(c)
6
3J 8, JPtH 68
4.43 d
3J 14, JPtH 68
4.55 d
2.28 s: H-17
6.40 s: NH2
2.31 s:H-17
6.39 s: NH2
2.30 s: H-17
6.16 s: NH2
3.83 s: H-17
7.35 s: NH2
3.80 s: H-17
7.25 s: NH2
3.81 s: H-17
7.08 s
(d)
7
3J 7.5, JPtH 68
4.42 d
3J 14, JPtH 68
4.53 d
7.15 d
3J 8.5
7.11 d
7.11 d
3J 8.5
6.87 td
3J 8, 4J 1.5
7.26 t
3J8.5
7.15 d
3J 8.5
7.29 dd
3J 8, 4J 1.5
7.02 d
3J 8.5
(c)
8
3J 7.5, JPtH 65
4.44 d
3J 14, JPtH 65
4.57 d
3J 8.5
6.99 dd
3J 8, 4J 1.5
7.15 td
(d)
9
3J 7, JPtH 65
4.41 dd, 2J 1.5
3J 7.5, JPtH 65
4.37 dd, 2J 1.5
3J 7.5, JPtH 65
3J 15, JPtH 65
4.54 dd, 2J 1.5
3J 14, JPtH 65
4.49 dd, 2J 1.5
3J 14, JPtH 65
3J 8, 4J 1.5
6.88 dd
7.07 t
4J 2
7.34 d
3J 9
(c)
10
(c)
a
3J 8.5, 4J 2
6.87 d
3J 8
6.87 d
3J 8
7.34 d
3J 9
Solvent, a: CD3OD, b: CDCl3, c: CD3COCD3, d: CD3CN.
2.87 ppm and another at 3.18 ppm) and two 13C signals at
49.67 and 49.71 ppm; two CH3 group give rise to one pro-
ton signal (at 1.408 ppm) but two 13C signals (at 14.64 and
14.74 ppm). In the spectra of 4b recorded in d6-acetone,
two CH3 groups of dimethylamine give rise to two proton
signals (at 2.65 and 2.70 ppm) and two 13C signals (at 40.09
and 41.99 ppm). The analogous appearance was still
observed when d6-acetone was replaced by CD3CN or
CD3Cl. Whilst for cis-[Pt(Morpholine)(Et2NH)Cl2], the
two CH2 groups of ethylamine give rise to one proton sig-
nal, and the two CH3 groups of ethylamine also give rise to
one proton signal [7], for trans-[PtCl2(C2H4)(Et2NH)] the
two CH2 groups of ethylamine give rise to one carbon sig-
nal (at 48.979 ppm), and the two CH3 groups of ethylamine
also give rise one carbon signal (at 14.699 ppm) and one
proton signal (at 1.573 ppm). This asks the question, what
causes the two ethyl groups in trans-[Pt(Meug)(Et2NH)Cl2]
to become non-equivalent?
To answer this, we recorded NOESY spectra of 4, 4a, 4b,
7 and 8. The signals of H-9, H-10 cis and H-10 trans of all the
10 complexes are shaped and resolved. The cross peaks n and
p (Fig. 2) indicate that only group CH2-a (H-12a) is adjacent

3274
T.T. Da et al. / Polyhedron 26 (2007) 3271–3276
Table 4
13C NMR signals of complexes 1–10, d (ppm) (For numeration of the C atoms see formula I–IV, for solvents see Table 2)
1
2
3
4
5
6
7
8
9
10
C-1
C-2
C-3
C-4
C-5
C-6
C-7a
C-7b
C-8
148.97
150.38
114.29
133.74
122.10
113.21
56.58
149.08
150.41
113.87
132.56
121.62
113.08
56.18
147.81
149.03
112.24
131.03
120.84
111.49
55.97
149.21
150.52
114.07
132.24
121.81
113.28
56.27
149.06
150.39
113.11
132.08
121.83
113.85
56.21
148.80
150.08
112.74
132.26
121.84
113.79
56.32
148.89
150.17
112.90
132.39
121.89
113.93
56.42
148.83
150.11
113.88
132.30
121.47
112.85
56.25
148.10
150.40
111.70
130.68
121.83
113.07
56.08
148.79
150.08
112.74
132.30
121.85
113.83
56.30
56.54
39.87
56.08
40.14
55.97
40.10
56.12
40.13
56.08
39.70
56.28
39.80
56.34
39.82
56.27
39.89
55.76
40.01
56.27
39.77
C-9
92.11
65.20
98.01
69.26
99.71
69.35
99.21
69.19
101.44
70.08
146.39
132.12
100.48
69.21
140.82
127.18
100.45
69.20
138.52
130.67
99.64
68.45
130.52
152.00
101.08
70.04
132.29
116.48
100.62
69.19
133.30
124.30
C-10
C-11
C-12
32.22
49.71
49.67
14.74
14.67
C-13
121.87
140.31
122.66
112.88
161.23
115.29
C-14
C-15
C-16
C-17
127.46
128.05
131.59
19.13
120.10
123.38
130.05
21.41
135.99
122.66
130.67
20.94
126.98
121.81
124.11
56.83
113.63
113.92
131.00
56.21
158.55
115.29
124.30
56.21
to the protons H-7b and H-8a, while group CH2-b (H-12b) is
not. This demonstrates that a rotation around the coordina-
tion axes (Pt–olephin bond and Pt–N bond) does not occur
on the NMR timescale at the recorded temperature. Thus
the atom Pt becomes asymmetrical.
3. Experimental
Elemental analysis: Pt was analyzed according to the
weight method [8], and C, H, N analyses were performed
at the Ho Chi Minh City Center of Analytical Service.
Experimentation used an automatic elemental analyzer.
The molar conductivity was measured using a conductivity
Meter HI 88119 N. The UV spectra were recorded on a
GCB Instrument-2855 spectrophotometer. The Raman
spectra were carried out on a Micro Raman LABRAM
in the range 4000–100 cmꢁ1, using excited radiation at
632.8 nm from a heli-neon laser. The IR spectra were
recorded on an IMPACK-410 NICOLET spectrometer in
KBr discs in the range 400–4000 cmꢁ1. The NMR spectra
were recorded on a Bruker AVANCE 500 MHz, all at
298–300 K, with TMS as the internal standard in a suitable
solvent (Tables 2 and 3).
Fig. 1. A part of the HMBC spectrum of [Pt(Meug)(o-CH3O-
C6H4NH2)Cl2] (8).
3.1. 4-Allyl-1,2-dimethoxybenzene (Methyleugenol, Meug)
Methyleugenol is prepared by reaction of eugenol (from
Ocimum Sanetum L.) with dimethyl sulfate in alkaline med-
ium, Bp. (15 mm Hg), 125–126 °C; (125–127 °C, according
to [9]). 1H NMR (CDCl3, d, ppm, J, Hz, formula I): 6.61, d,
3
3
4J 1.8, 1H: H3; 6.62, dd, J 8, 4J 1.8, 1H: H5; 6.68, d, J 8,
3
1H: H6; 3.73, s, 3H, 3.75, s, 3H: H7a, H7b; 3.22, d, J 6.5,
2H: H8; 5.86, m, 1H: H9; 4.96, m, J cis 7, 1H: H10 cis; 4.98,
m, J trans 12.5, 1H: H10 trans.
Fig. 2. A part of the NOESY spectrum of [Pt(Meug)(Et2NH)Cl2] (4).

T.T. Da et al. / Polyhedron 26 (2007) 3271–3276
3275
3.2. Potassium trichloro(methyleugenol)platinat(II),
K[Pt(Meug)Cl3] (1)
of 2. The yield was 0.44 g (80%), light yellow crystals. Anal.
Calc. for [PtC18H23NO2Cl2]: Pt, 35.39; C, 39.20; H, 4.17;
N, 2.54. Found: Pt, 35.52; C, 39.48; H, 4.32; N, 2.32%.
To a stirred solution of 3.68 g (10 mmol) of Zeise’s salt
in 80 ml of ethanol was slowly added a solution of 2.5 ml
(16 mmol) of methyleugenol in 20 ml of ethanol. The reac-
tion mixture was stirred at 40–45 °C for an hour. Then it
was allowed to cool to room temperature. Yellow plate
crystals were collected and washed with cool water, then
cool ethanol, and were then dried in a vacuum at 50 °C
for 2 h. The yield was 4.15 g (80%). For 1H and 13C
NMR see Tables 2–4. Anal. Calc. for KPtC11H14O2Cl3:
Pt + K2SO4, 54.39; C, 24.46; H, 2.70. Found: Pt + K2SO4,
54.75; C, 24.18; H, 2.54%.
3.7. trans-Dichloro(methyleugenol)(m-toluidine)-
platinum(II), [Pt(Meug)(m-CH3C6H4NH2)Cl2] (6)
This complex was prepared starting from 0.52 g
(1 mmol) K[Pt(Meug)Cl3], 0.118 g (1.1 mmol) m-toluidine,
at 25–30 °C, according to the procedure for the preparation
of 2. The yield was 0.40 g (75%), light yellow crystals. Anal.
Calc. for [PtC18H23NO2Cl2]: Pt, 35.39; C, 39.20; H, 4.17;
N, 2.54. Found: Pt, 35.25; C, 39.37; H, 4.35; N, 2.65%.
3.8. trans-Dichloro(methyleugenol)(p-toluidine)-
platinum(II), [Pt(Meug)(p-CH3C6H4NH2)Cl2] (7)
3.3. trans-Dichloro(methyleugenol)(ammine)platinum(II),
[Pt(Meug)(NH3)Cl2] (2)
This complex was prepared starting from 0.52 g
(1 mmol) K[Pt(Meug)Cl3], 0.118 g (1.1 mmol) p-toluidine,
at 25–30 °C, according to the procedure for the preparation
of 2. The yield was 0.38 g (70%), light yellow crystals. Anal.
Calc. for [PtC18H23NO2Cl2]: Pt, 35.39; C, 39.20; H, 4.17;
N, 2.54. Found: Pt, 35.51; C, 39.38; H, 4.36; N, 2.72%.
K[Pt(Meug)Cl3] (0.518 g, 1 mmol) was dissolved in
16 ml of 50% by volume aqueous EtOH. To this solution
8 ml of 1.5 M NH3 solution was slowly added over 30 min-
utes and stirred at 10–15 °C for an additional 3 h. The
resulting yellow precipitate was collected, washed with a
solution of 0.1 N HCl, cool water, cool ethanol and recrys-
tallized from 75% by volume aqueous EtOH. The light yel-
low crystals were dried in a vacuum at 50 °C for 2 h. The
yield was 0.32 g (70%). Anal. Calc. for [PtC11H17NO2Cl2]:
Pt, 42.30; C, 28.63; H, 3.69; N, 3.04. Found: Pt, 42.58; C,
28.40; H, 3.88; N, 2.82%.
3.9. trans-Dichloro(methyleugenol)(o-anisidine)-
platinum(II), [Pt(Meug)(o-CH3OC6H4NH2)Cl2] (8)
This complex was prepared starting from 0.52 g
(1 mmol) K[Pt(Meug)Cl3], 0.11 ml (1.1 mmol) o-anisidine,
at 25–30 °C, according to the procedure for the preparation
of 2. The yield was 0.48 g (84%), light yellow crystals. Anal.
Calc. for [PtC18H23NO3Cl2] (%): Pt, 34.39; C, 38.09; H,
4.06; N, 2.47. Found: Pt, 34.54; C, 38.22; H, 4.21; N,
2.33%.
3.4. trans-Dichloro(methyleugenol)(methylamine)-
platinum(II), [Pt(Meug)(MeNH2)Cl2] (3)
This complex was prepared starting from 0.52 g
(1 mmol) K[Pt(Meug)Cl3] and 1.3 ml aqueous solution of
30% methylamine (1.2 mmol), according to the procedure
for the preparation of 2. The yield was 0.36 g (75%), light
yellow crystals. Anal. Calc. for [PtC12H19NO2Cl2]: Pt,
41.05; C, 30.32; H, 4.00; N, 2.95. Found: Pt, 41.30; C,
29.98; H, 4.12; N, 2.76%.
3.10. trans-Dichloro(methyleugenol)(m-anisidine)-
platinum(II), [Pt(Meug)(m-CH3OC6H4NH2)Cl2] (9)
This complex was prepared starting from 0.52 g
(1 mmol) K[Pt(Meug)Cl3], 0.11 ml (1.1 mmol) m-anisidine,
at 25–30 °C, according to the procedure for the preparation
of 2. The yield was 0.45 g (81%), light yellow crystals. Anal.
Calc. for [PtC18H23NO3Cl2] (%): Pt, 34.39; C, 38.09; H,
4.06; N, 2.47. Found: Pt, 34.21; C, 38.25; H, 3.87; N,
2.62%.
3.5. trans-Dichloro(methyleugenol)(diethylamine)-
platinum(II), [Pt(Meug)(Et2NH)Cl2] (4)
This complex was prepared starting from 0.52 g (1 mmol)
K[Pt(Meug)Cl3], 0.13 ml (1.2 mmol) diethylamine, accord-
ing to the procedure for the preparation of 2. The yield
was 0.36 g (70%), light yellow crystals. Anal. Calc. for
[PtC15H25NO2Cl2] (%): Pt, 37.72; C, 34.82; H, 4.83; N,
2.71. Found: Pt, 37.58; C, 34.98; H, 4.62; N, 2.89%.
3.11. trans-Dichloro(methyleugenol)(p-anisidine)-
platinum(II), [Pt(Meug)(p-CH3OC6H4NH2] (10)
This complex was prepared starting from 0.52 g
(1 mmol) K[Pt(Meug)Cl3], 0.123 g (1.1 mmol) p-anisidine,
at 25–30 °C, according to the procedure for the preparation
of 2. The yield was 0.46 g (82%), light yellow crystals. Anal.
Calc. for [PtC18H23NO3Cl2] (%): Pt, 34.39; C, 38.09; H,
4.06; N, 2.47. Found: Pt, 34.26; C, 37.91; H, 4.26; N,
2.29%.
3.6. trans-Dichloro(methyleugenol)(o-toluidine)platinum(II),
[Pt(Meug) (o-CH3C6H4NH2)Cl2] (5)
This complex was prepared starting from 0.52 g
(1 mmol) K[Pt(Meug)Cl3], 0.12 ml (1.1 mmol) o-toluidine,
at 25–30 °C, according to the procedure for the preparation

3276
T.T. Da et al. / Polyhedron 26 (2007) 3271–3276
[5] L. Colla’r, E. Farkas, J. BÓtiv, J. Mol. Catal. A: Chem. 115 (1977) 283.
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