Synthesis and characterization of Zn(II) and Cd(II) complexes with bisdithiophosphonates

Article abstract of DOI:10.1007/s11173-005-0096-0

2,4-Bis(4-methoxyphenyl)-1,3,2,4-dithiodiphosphetane-2,4-disulfide (Lawesson's reagent) reacts with stoichiometric equivalent of alkane diols HO(CH₂)_nOH (n=2, 3, and 5) to form bisdithiophosphonic acid. The obtained crude bisdithioph

Full text of DOI:10.1007/s11173-005-0096-0

Russian Journal of Coordination Chemistry, Vol. 31, No. 5, 2005, pp. 316–321. From Koordinatsionnaya Khimiya, Vol. 31, No. 5, 2005, pp. 338–343.
Original English Text Copyright © 2005 by Karakus, Yilmaz, Bulak.
Synthesis and Characterization of Zn(II)
and Cd(II) Complexes with Bisdithiophosphonates1
M. Karakus*, H. Yilmaz**, and E. Bulak***
*Department of Chemistry, Faculty of Arts and Science, Pamukkale University, 20017 Kinikli/Denizli, Turkey
e-mail: mkarakus@pamukale.edu.tr
**Department of Chemistry, Faculty of Science, Ankara University, 06100 Tandogan-Ankara, Turkey
***Chemistry Department, Bogazici University, 34000 Bebek-Istanbul, Turkey
Received July 8, 2004
Abstract—2,4-Bis(4-methoxyphenyl)-1,3,2,4-dithiodiphosphetane-2,4-disulfide (Lawesson’s reagent) reacts
with stoichiometric equivalent of alkane diols HO(CH2)nOH (n = 2, 3, and 5) to form bisdithiophosphonic acid.
The obtained crude bisdithiophosphonic acids are treated with dry NH3 to give ammonium salts of bisdithiophos-
phonic acids. Ammonium salts of bisdithiophosphonic acids react with ZnSO4 in water and Cd(Ac)2 in ethanol to
form new bisdithiophosphonate complexes of Zn(II) and Cd(II). The zinc and cadmium complexes of these tet-
radentate ligands are isolated in high yields. Ammonium salts of bisdithiophosphonic acids and their Zn(II) and
Cd(II) complexes are characterized by elemental analyses, mass spectra (ESI), IR and NMR spectroscopies.
1
INTRODUCTION
from Aldrich, benzene and DMSO—from Merck. Eth-
anol (thecnical grade) was distilled before use. Melting
points were determined with a Gallenkamp apparatus
without correction. Elemental analyses were performed
with a VARIO EL (Heraeus). IR spectra were recorded
on a Mattson 1000 FTIR spectrophotometer with KBr
pellets. NMR spectra (1H, 13C, and 31P) were recorded
at 400 MHz on Bruker DPX-400 and Bruker AC 250
spectrometers in DMSO-D6 and D2O.
Ammonium-O,O-(1,2-ethenyl)bis[(4-methoxy-
phenyl)dithiophosphonate] (I). Compound A (4.16 g,
10 mmol) was mixed with benzene (5 ml) in a 100-ml
flask, and 1,2-ethanediol (0.55 ml, 10 mmol) was added
dropwise to this mixture. The temperature was main-
tened at about 80°C until complete dissolution of all
solids. The obtained crude bisdithiophosphonic acid
was filtered, the filtrate was cooled to 10°C, and the
acid was converted to I by the reaction of dry NH3. The
precipitated compound I was filtered off, washed with
cold benzene, and dried in air. The product was recrys-
tallized from methanol. A colorless crystaline solid was
filtered and air-dried. The yield was 3.58 g (82%);
mp 159°C.
Ammonium-O,O-(1,3-propenyl)bis[(4-methoxy-
phenyl)dithiophosphonate] (II). In a similar manner
compound A (2.08 g, 5 mmol) in benzene (5 ml)
reacted with 1,3-propanediol (~0.37 ml, 5 mmol).
Compound II was isolated by the above procedure
given for compound I. The yield was 2.21 g (86%),
mp 159°C.
Ammonium-O,O-(1,5-pentenyl)bis[(4-methoxy-
phenyl)dithiophosphonate] (III). In a similar manner
compound A (8.34 g, 20 mmol) in benzene (5 ml)
The compounds derived from reactions of organo-
phosphorodithio ligands such as dithiophosphonate [1–
10], dithiophosphinato [11, 12], and dithiophosphate
[13–16] with transition metals, have significant proper-
ties and were efficiently used in technological and agri-
cultural fields. For example, these ligands were used as
antioxidants for lubrication oils, flotation agents for
mineral ores, solvent extraction agents for metal cat-
ions, insecticides and pesticides [1, 2, 4]. An example
of dinuclear complexes of Cd(II) with dithiophospho-
nate has recently been reported [10]. In addition, dinu-
clear complexes of Zn(II) and Cd(II) with dithiophos-
phates and dithiophosphinates have been characterized
[12, 16]. The reactions of 2,4-bis(4-methoxyphenyl)-
1,3,2,4-dithiadiphosphetane-2,4-disulfide (A) with alkane
diols (B) were investigated by Sahabane et al. [17].
Methylthionophosphine sulfide reacted with ethylene
glycol to give O,O-(1,2-ethylene)bis(metyldithiophos-
phonic acid) [3]. However, the coordination chemistry
of tetradentate bisdithiophosphonate ligands with
metal cations and their properties remains insuffi-
ciently studied.
In the present study, we report the preparation and
characterization of new monomer and dimer Zn(II) and
Cd(II) complexes with tetradentate bisdithiophospho-
nate ligands.
EXPERIMENTAL
Compound A (Lawesson’s reagent), 1,2-ethanediol,
1,3-propanediol, and 1,5-pentanediol were purchased
1
This text was submitted by the authors in English.
1070-3284/05/3105-0316 © 2005 Pleiades Publishing, Inc.

SYNTHESIS AND CHARACTERIZATION OF ZN(II) AND CD(II) COMPLEXES
317
Table 1. Analytical and physical details of ligands (I–III) and their complexes with Zn2+ and Cd2+ (Ia–IIIa and Ib–IIIb,
respectively)
Elemental analyses (calcd/found, %)
Compound
Empirical formula
Yield, % Mp, °C
Mass
C
H
N
S
I
C16H26N2O4P2S4
C17H28N2O4P2S4
C19H32N2O4P2S4
82
86
86
162–163
159
38.39/37.30 5.23/5.70 5.59/5.51 25.62/23.67
39.67/40.38 5.48/4.76 5.44/5.24 24.92/22.38
42.06/41.45 5.90/6.12 5.16/4.89 23.61/22.30
II
III
>195
(decomp.)
Ia
[(C18H24O4P2S4)2Zn2]
C18H24O4P2S4Cd
56
62
84
66
79
88
>190
1060.78 36.26/36.1 3.42/3.15
(ESI)
24.20/24.30
22.23/21.70
23.58/22.80
21.70/20.90
22.42/21.00
20.71/19.40
(decomp.)
Ib
>190
(decomp.)
*
33.31/32.50 3.14/3.43
IIa
IIb
IIIa
C18H22O4P2S4Zn
>158
(decomp.)
*
37.56/37.30 3.70/3.35
[(C18H22O4P2S4)2Cd2]
C19H24O4P2S4Zn
>160
(decomp.)
1182.77 34.55/34.50 3.41/2.99
(ESI)
>160
(decomp.)
570.93
(ESI)
39.89/39.2 4.22/4.86
IIIb
[(C19H24O4P2S4)2Cd2]
>160
(decomp.)
1238.81 36.86/36.90 3.90/3.32
(ESI)
+
* [M] was not observed.
reacted with 1,5-pentanediol (~2.125 ml, 20 mmol).
Preparation of Zn(II)-bis[O,O-(1,3-propenyl)bis[(4-
Compound III was isolated by the above procedure methoxyphenyl)dithiophosphonate] (IIa). As in the
given for compound I. The yield was 8.94 g (86%), mp case of compound Ia, ZnSO4 · 7H2O (0.58 g, 2.02 mmol)
195°C (decomp).
was dissolved in water (25 ml), and this solution was
added dropwise to an aqueous solution of compound II
(1.04 g, (2.02 mmol). A white precipitate formed
immediately, and was recrystallized from a mixture of
DMSO and ethanol (1 : 3). The yield was 0.92 g (84%),
mp > 158°C (decomp.).
Preparation of Cd(II)-bis[O,O-(1,3-propenyl)bis[(4-
methoxyphenyl)dithiophosphonate] (IIb). As in the
case of compound Ib, Cd(CH3COO)2 · 2H2O (0.49 g,
1.84 mmol) was dissolved in ethanol (25 ml), and this
solution was added dropwise to an aqueous solution of
compound II (0.94 g, 1.84 mmol). A white precipitate
was obtained and recrystallized from DMSO and etha-
nol (1 : 3). The yield was 0.71 g (65%), mp > 160°C
(decomp.).
Preparation of Zn(II)-bis[O,O-(1,2-ethenyl)bis[(4-
methoxyphenyl)dithiophosphonate] (Ia). Compound I
(0.13 g, 0.259 mmol) was dissolved in water (25 ml),
and a solution of ZnSO4 · 7H2O (0.074 g, 0.259 mmol)
in water (10 ml) was added dropwise to a solution of I.
The mixture was stirred for 1 h at room temperature.
The white precipitated complex was filtered off and
washed with ethanol. The product was recrystallized
from a mixture of DMSO and ethanol (1 : 3). The yield
was 0.076 g (56%), mp 190°C (decomp.).
Preparation of Cd(II)-bis[O,O-(1,2-ethenyl)bis[(4-
methoxyphenyl)dithiophosphonate] (Ib). Com-
pound I (0.34 g, 0.679 mmol) was dissolved in ethanol
(25 ml) and a solution of Cd(CH3COO)2 · 2H2O (0.18 g,
Preparation of Zn(II)-bis[O,O-(1,5-pentenyl)bis[(4-
0.679 mmol) in ethanol (25 ml) was added dropwise to methoxyphenyl)dithiophosphonate] (IIIa). In a man-
a solution of I. The mixture was stirred for 1 h at room ner similar to that for compound Ia, ZnSO4 · 7H2O
temperature. The white precipitated complex was fil- (0.09 g, 0.31 mmol) was dissolved in water (10 ml) and
tered off and washed with ethanol. The product was this solution was added dropwise to an aqueous solu-
recrystallized from a mixture of DMSO and ethanol tion of compound IIIa (0.17 g, 0.31 mmol)A white pre-
(1 : 3). The complex was isolated as a colorless crysta- cipitate formed immediately and was recrystallized
line product. The yield was 0.24 g (62%), mp 190°C from a mixture of DMSO and ethanol (1 : 3). The yield
(decomp.).
was 0.58 g (79%), mp > 160°C (decomp.).
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 31 No. 5 2005

318
KARAKUS et al.
Table 2. Selected IR bands (cm–1) of complexes I–III, Ia–IIIa, and Ib–IIIb
Compound
ν(N–H)
ν(P=S)
ν(P–O–C)
νas(PS)
νa(PS)
I
3158
3102
3119
669
686
671
1018
1028
1030
1022
1022
1027
1026
1026
1026
II
III
Ia
645
660
644
645
645
645
542
539
543
543
545
544
Ib
IIa
IIb
IIIa
IIIb
Preparation of Cd(II)-bis[O,O-(1,5-pentenyl)bis[(4-
methoxyphenyl)dithiophosphonate] (IIIb). In a man-
ner similar to that with compound Ib, Cd(CH3COO)2 ·
2H2O (0.56 g, 2.1 mmol) was dissolved in ethanol
(25 ml) and this solution was added dropwise to an
aqueous solution of compound IIIb (1.14 g, 2.1 mmol).
A white precipitate was obtained and was recrystallized
from DMSO and ethanol (1 : 3). The yield was 1.3 g
(88%), mp >160°C (decomp.).
The elemental analyses of compounds I–III, Ia–
IIIa and Ib–IIIb are given in Table 1; IR date—in
1
Table 2; H, 31P, and 13C (1H for complexes) NMR
data—in Tables 3, 4, respectively.
RESULTS AND DISCUSSION
The ligands are obtained according to the following
scheme:
S
P
S
S
C6H6
MeO
P
S
OMe + HO (CH2)n OH
(B)
(A)
O
(CH2)n
O
MeO
P S
SH
S P
OMe
OMe
SH
(C)
C6H6, NH3
O
(CH2)n
O
MeO
P S
S P
–
–
+
+
S] NH4
S] NH4
(I–III)
Note. I: 1,2-ethanediol, n = 2;
II: 1,3-propandiol, n = 3;
III: 1,5-propandiol, n = 5.
The compounds described in this paper were char-
acterized by elemental analyses, 1H, 13C{1H} (only for
complexes), 31P{1H} NMR and mass spectroscopies.
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SYNTHESIS AND CHARACTERIZATION OF ZN(II) AND CD(II) COMPLEXES
319
1
Table 3. H and 31P{1H}NMR spectral data of all compounds (δ, ppm)
Com-
pound
31P
*
OCH2CH2
H(orto H to P) H(meta H to P)
OCH2
OCH2CH2CH2
OCH3
I*
7.85–7.79
(d.d., 4H)
6.82–6.80
(d.d., 4H)
3.89
(d., 4H)
3.68
(s., 6H)
107.66
4
3JP,H = 13.68 Hz JP,H = 1.96 Hz 3JP,H = 16.00 Hz
JH,H = 8.80 Hz
JH,H = 8.80 Hz
II*
8.03–7.98
(d.d., 4H)
7.06–7.03
(d.d., 4H)
4.11–4.02
(m., 4H)
2.91
3.89
107.02
106.72
104.32
(m., 2H)
(s., 6H)
3JP,H = 13.51 Hz JP,H = 2.20 Hz
4
JH,H = 8.56 Hz
JH,H = 8.70 Hz
III*
Ia**
7.96–7.91
(d.d., 4H)
7.02–6.99
(d.d., 4H)
3.78–3.82
(m., 4H)
1.58–1.51
(m., 4H)
1.38–1.32
(m., 2H)
3.85
(s., 6H)
3JP,H = 13.43 Hz JP,H = 2.28 Hz
4
JH,H = 8.60 Hz
JH,H = 8.71 Hz
7.92–7.86
(d.d., 4H)
6.94–6.87
(d.d., 4H)
4.0
(br., 4H)
3.78
(s., 6H)
4
3JP,H = 13.40 Hz JP,H = not ob-
served
JH,H = 8.60Hz
JH,H ≈ 8.0 Hz
Ib**
7.92–7.86
(d.d., 4H)
6.98–6.96
(d.d., 4H)
4.37
3.79
106.88
100.51
104.43
101.96
104.37
(br., 4H)
(s., 6H)
3JP,H = 13.60 Hz JP,H = 2,40 Hz
4
JH,H = 8.40 Hz
JH,H = 8.40 Hz
IIa**
IIb**
IIIa**
IIIb**
8.55–8.46
(d.d., 4H)
7.59–7.64
(d.d., 4H)
4.68–4.58
(m., 4H)
2.54–2.44
(m., 2H)
3.99
(s., 6H)
3JP,H = 13.47 Hz JP,H = 2.65 Hz
4
JH,H = 8.61 Hz
JH,H = 8.77 Hz
7.91–7.82
(d.d., 4H)
6.97–6.93
(d.d., 4H)
4.26
(m., 4H)
2.11–2.0
(m., 2H)
3.76
(s., 6H)
3JP,H = 13.86 Hz JP,H = 2.88 Hz
4
JH,H = 8.80 Hz
JH,H = 8.88 Hz
7.89–7.84
(d.d., 4H)
6.93–6.90
(d.d., 4H)
3.86–3.78
(m., 4H)
1.55–1.50
(m., 4H)
1.36–1.30
(m., 2H)
3.77
(s., 6H)
3JP,H = 13.20 Hz JP,H = 2.60 Hz
3
JH,H = 8.80 Hz
JH,H = 8.82 Hz
7.91–7.85
(d.d., 4H)
6.98–6.96
(d.d., 4H)
4.23–4.18
(m., 4H)
1.70–1.74
(m., 4H)
1.48–1.43
(m., 2H)
3.78
(s., 6H)
3
3JP,H = 13.80 Hz JP,H = 2.60 Hz
JH,H = 8.60 Hz
JH,H = 8.60Hz
* In D O.
2
** In DMSO-D .
6
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320
KARAKUS et al.
Table 4. 13C{1H} NMR spectral data of all complexes (δ, ppm) (DMSO-D6)
Com-
pound
C1
C2
C3
C4
C5
C6
C7
C8
Ia
133.92
13.66
112.86
160.76
55.32
63.39
2JP,C = 6.62 Hz
64.58
1JP,C = 119.09 Hz JP,C = 13.65 Hz JP,C = 14.89 Hz
2
3
Ib
131.66 131.70 113.27
161.22
55.36
2
3
4
1JP,C = 119.12 Hz JP,C = 13.88 Hz JP,C = 15.19 Hz JP,C = 2.90 Hz
2JP,C not ob-
served
IIa
IIb
134.24
1JP,C = 114.47 Hz JP,C = 13.30 Hz JP,C = 14.80 Hz
132.08 131.55 113.40
131.53
112.94
160.72
55.35
55.40
60.45
2JP,C = 5.9 Hz
61.74
30.43
30.65
2
3
161.20
2
3
4
1JP,C = 117.62 Hz JP,C = 13.70 Hz JP,C = 15.20 Hz JP,C = 3.20 Hz
2JP,C not ob-
served
IIIa
IIIb
134.83
131.93
113.14
160.95
55.67
55.69
63.71
29.87
22.05
22.12
1JP,C = 114.14 Hz JP,C = 13.23 Hz JP,C = 14.48 Hz
2JP,C not ob- JP,C = 8.60 Hz
2
3
3
served
132.17
131.93
113.68
161.58
64.49
29.63
3
3
3
1JP,C = 121.16 Hz JP,C = 13.65 Hz JP,C = 15.19 Hz
3JP,C = 6.33 Hz JP,C = 7.44 Hz
The reaction of compound A with alkane diols (B) cooled benzene. The reaction of I–III with ZnSO4
in a 1 : 1 ratio gave rise to formation of bisdithio- and Cd(CH3COO)2 gave complexes (Ia–IIIa and Ib–
phosphonic acids (C). To convert their ammonium IIIb, respectively) according to the following
salts (I–III), these acids reacted with dry NH3 in scheme:
O
(CH2)n
O
1) ZnSO4, H2O
2) Cd(CH COO)2, C2H5OH
3
MeO
P S
–
S P
OMe
[Mn(L)n]
–
+
+
S] NH4
S] NH4
(M = Zn, Cd)
These complexes were isolated in high yield, and can be monomers or dimers:
O
(CH2)n
O
MeO
P S
S
S P
OMe
OMe
S
O
(CH2)n
O
MeO
P S
S
S P
OMe
M
S
M
M
S
S
MeO
P S
O
S P
(CH2)n
O
Mononuclear
Dinuclear
The IR spectra of the ligands (I–III) showed bands ings. The bands in regions 1018–1030 and 669–686 cm–1
in a region 3102–3158 cm–1 assigned to ν(N–H) stretch- can be assigned to ν(P–O–C) and ν(P=S), respec-
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 31 No. 5 2005

SYNTHESIS AND CHARACTERIZATION OF ZN(II) AND CD(II) COMPLEXES
321
tively [17, 18]. In the IR spectra of the complexes, the
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