N,N'-bis(triethoxysilylmethyl)thiocarbamide and poly[N,N'-bis(silsesquioxanylmethyl)thiocarbamide S,S-dioxide]

Article abstract of DOI:10.1007/s11176-005-0373-0

Condensation of (aminomethyl)triethoxysilane with thiocarbamide in the presence of catalytic amounts of ammonium sulfate was used to synthesize N,N-bis(triethoxysilylmethyl)thiocarbamide. The latter was brought into oxidative hydrolytic polycondensation with H₂O₂ to obtain poly[N,N'-bis(silsesquioxanylmethyl)thiocarbamide S, S-dioxide] whose properties were compared with the properties of poly[N,N'-bis(silsesquioxanylpropyl)thiocarbamide S,S-dioxide]. Both polymers in highly acidic media rather strongly absorb Ag(I), while at pH 7 they reduce most absorbed Ag⁺ to the metal. Their reaction with potassium permanganate involves reduction of Mn⁷⁺ to Mn⁴⁺. The first polymer is a less effective sorbent and redox agent than the second. 2005 Pleiades Publishing, Inc.

Full text of DOI:10.1007/s11176-005-0373-0

Russian Journal of General Chemistry, Vol. 75, No. 7, 2005, pp. 1091 1093. Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 7, 2005,
pp. 1154 1156.
Original Russian Text Copyright
2005 by Voronkov, Vlasova, Grigor’eva, Pozhidaev, Bol’shakova.
N,N -Bis(triethoxysilylmethyl)thiocarbamide and Poly[N,N -
bis(silsesquioxanylmethyl)thiocarbamide S,S-dioxide]
M. G. Voronkov, N. N. Vlasova, O. Yu. Grigor’eva,
Yu. N. Pozhidaev, and S. A. Bol’shakova
Favorskii Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, Irkutsk, Russia
Received February 27, 2004
Abstract Condensation of (aminomethyl)triethoxysilane with thiocarbamide in the presence of catalytic
amounts of ammonium sulfate was used to synthesize N,N-bis(triethoxysilylmethyl)thiocarbamide. The latter
was brought into oxidative hydrolytic polycondensation with H O to obtain poly[N,N -bis(silsesquioxanyl-
2
2
methyl)thiocarbamide S,S-dioxide] whose properties were compared with the properties of poly[N,N -bis(sil-
sesquioxanylpropyl)thiocarbamide S,S-dioxide]. Both polymers in highly acidic media rather strongly absorb
+
Ag(I), while at pH 7 they reduce most absorbed Ag to the metal. Their reaction with potassium per-
7
+
4+
manganate involves reduction of Mn to Mn . The first polymer is a less effective sorbent and redox agent
than the second.
Previously we reported the synthesis of the first
polysiloxane polymer containing a unique carbofun-
Thiocarbamide III undergoes an extremely facile
thermolysis into starting amine IV and triethoxysilyl-
methyl isothiocyanate (V).
ctional group NHC(SO )NH, viz. poly[N,N -bis(sil-
2
sesquioxanylpropyl)thiocarbamide S,S-dioxide] (I) [1].
This polymer was found to exhibit a number of
unique properties. It effectively absorbs rare-earth
metal ions with a fairly strong tetrad effect that is
poorly understood in regard of rare-earth metals [2].
In reaction with rare-earth metal ions, such as vana-
dium(V), tungsten(VI), and molybdenum(VI), it func-
tions as ampholite and reacts with both anionic and
cationic forms of these metals [3]. Polymer I, like
thiocarbamide dioxide and its organic derivatives [4],
possesses redox properties [5].
III
IV + (EtO)3SiCH2NCS.
V
We found that the optimal reaction temperature is
60 170 C. Since thiocarbamide III decomposed
1
during vacuum distillation, its purification was per-
formed by filtering the reaction mixture to remove
solid admixtures and subsequent exposure to high
vacuum (0.1 0.4 mm Hg) at room temperature. The
lack in thiocarbamide III of an admixture of com-
pound V was judged about by the disappearance from
the IR spectrum of the characteristic N=C=S stretch-
Proceeding with the research into organosilicon
polymers with ion-exchange and complexing proper-
ties, we have synthesized an analog of polymer I in
which the silicon and nitrogen atoms are intervened
by a methylene rather than trimethylene bridge, viz
poly[N,N -bis(silsesquioxanylmethyl)thiocarbamide
S,S-dioxide] (II), and studied its properties. Polymer
II was synthesized from previously unknown mono-
mer N,N -bis(triethoxysilylmethyl)thiocarbamide (III)
was prepared by condensation of (aminomethyl)tri-
ethoxysilane (IV) with thiocarbamide in the presence
of catalytic amounts of ammonium sulfate at 160
1
ing absorption band at 2100 2000 cm .
Polymer II was synthesized by oxidative hydrolytic
polycondensation of thiocarbamide III. This method
we developed previously [8] and used to prepare
polymer I [1]. The synthesis involves concurrent and
consecutive redox, hydrolysis, and polycondensation
reactions of the starting organosilicon monomer under
the action of 50 60% H O .
2
2
H O , H O
2
2
2
III
1/n[(O1.5SiCH NH CSO ]
2 2 2 n
1
70 C [6, 7].
+
6C H OH + 3H O.
2 5 2
2
(EtO) SiCH NH + H NC(S)NH
3
2
2
2
2
IV
The structure of polymer II is proved by its IR
spectrum and chemical behavior. The IR spectrum
contains a band at 1695 cm 1 [ (C=N)] that is also
(
NH ) SO
4 2 4
[
(EtO) SiCH NH] C=S + 2NH .
3
2
2
3
III
1
070-3632/05/7507-1091 2005 Pleiades Publishing, Inc.

1
092
VORONKOV et al.
1.08 g g 1 for polymer II in 0.01 M H SO , at pH 7,
present in the IR spectra of thiocarbamide dioxide [9],
polymer I [1], and other known organosilicon deriva-
tives of thiocarbamide dioxide [10, 11], which allows
polymer II to be considered as a derivative of form-
amidinesulfinic acid A or zwitter ion B.
2
4
and in 0.01 M NH OH, respectively.
4
The same effect we also observed in polyorgano-
siloxanes containing Si(CH ) Y and SiCH Y (Y =
2
3
2
SO H) groups [8]. This observation suggests that the
3
Si(CH ) Y group in the silsesquioxane skeleton is
sterically more accessible at n = 3.
2
n
O
OH
O
O
S
S
C
C
EXPERIMENTAL
+
RHN
NR
RH N
NR
2
The IR spectra were measured on a UR-20 instru-
ment in thin films. Spectrophotometry was performed
on a KFK-2 photocolorimeter.
A
B
R = CH SiO1.5.
2
The starting (chloromethyl)triethoxysilane was
prepared by the reaction of trichloro(chloromethyl)-
silane with absolute ethanol [12].
Polymer II does not melt and dissolve or swell in
water or organic solvents. It fairly actively absorbs
Ag(I) and, like thiocarbamide dioxide [4] and organo-
silicon thiocarbamide S,S-dioxides [1, 5, 10], exhibits
redox properties. Comparison of the sorption and
redox activities of polymers I and II with respect to
(Aminomethyl)triethoxysilane (IV). (Chloro-
methyl)triethoxysilane, 42.5 g, and 100 ml of liquid
ammonia dried with metallic sodium and passed
through a NaOH bed were placed in a 1-l autoclave.
The autoclave was heated for 6 h at 125 C; therewith,
the pressure in the autoclave rose to reach 115 atm.
The ammonia was then removed, and the product was
extracted from the residue with ether and isolated by
+
Ag suggests that both polymers act as fairly effective
sorbents for this metal in 1 3 M nitric acid. Therewith,
polymer I is more active. The Ag(I) sorption capacity
of these polymers depends on the acidity of the
medium, and at pH 7 and in 0.1, 1, and 3 M HNO it
3
1
varies from 675 (pH 7) to 149 mg g (3 M HNO ) for
3
polymer I and from 624 (pH 7) to 107 mg g 1 (3 M
vacuum distillation. Yield 7.8 g (20%), bp 53 55 C
25
(
8
3 mm Hg), nD 1.4090 {published data [12]: bp
HNO ) for polymer II.
25
3
0.5 C (14 mm Hg), nD 1.4082}. In addition, 5.0 g
In a weakly acidic medium (0.1 M HNO ), both
(12%) of N,N-bis(triethoxysilylmethyl)amine was
3
isolated, bp 130 C (3 mm Hg), n2 1.4180 {published
3
polymers commence to exhibit redox properties (5
D
+
0
25
1
0% Ag is reduced to Ag ). And, finally, in a neutral
data [13]: bp 117 C (3 mm Hg), nD 1.4132}.
medium (pH 7) they behave primarily as redox agents
+
0
and reduce 80% of absorbed Ag to Ag . However,
with polymer I this process takes 10 20 min, while
with polymer II, as long as 3 4 h.
N,N -Bis(triethoxysilylmethyl)thiocarbamide
(III). A mixture of 3 g of (aminomethyl)triethoxy-
silane (IV), 0.59 g of thiocarbamide, and 0.01 g of
ammonium sulfate was heated in a sealed ampule at
160 170 C for 7 h. Thiocarbamide II, 3.9 g (60%),
2
Ag+ + 1/n{[(O1.5Si(CH ) NH] CSO } + 2H O
2 m 2 2 n 2
was isolated, n2 1.4240. IR spectrum, cm : 3300
0
1
I, II
D
0
[ (NH)], 2980 and 2880 [ (CH)], 1520 [ (NH)], 1440
2
Ag + 1/n{[O Si(CH ) NH] C=O}
1.5 2 m 2 n
[
(CH)], 1260 [ (CN)], 1140 [ (C=S)], 1090 1050
[ (SiOEt)]. Found, %: C 43.32; H 8.14; S 7.02; Si
+
+
H SO + 2H .
2 3
1
8
1.60. C H N O SSi . Calculated, %: C 42.06; H
15 36 2 6 2
.40; S 7.47; Si 13.08.
In reaction with potassium permanganate polymer
II, like polymer I [5], reduces Mn to Mn .
7
+
4+
Poly[N,N -bis(silsesquioxanylmethyl)thiocar-
bamide S,S-dioxide] (II). To a solution of 2.2 g of
thiocarbamide II in 10 ml of chloroform, 0.34 g of
3
/n[(O1.5SiCH NH) CSO ] + 2KMnO4 + 2H O
2
2
2 n
2
6
0
0% H O was added dropwise with cooling to 5 to
3
/n[(O1.5SiCH NH) C=O] + 2MnO2
2 2
2
2
n
C. The mixture was stirred at room temperature for
1
+
K SO + 2H SO .
2 h. Yield 1 g (50%). IR spectrum, cm : 1695
(C=N)], 1400 [ (CH)], 1260 [ (CN)], 1100
2
3
2
3
[
Polymer I is more reactive toward Mn7+ than
polymer II. The reductive capacity of polymer I is
.67, 1.52, and 1.43 g g against 1.22, 1.52, and
[ (SiOSi)], 1010 [ (SO)], 620 [ (CS)]. Found, %:
C 16.56; N 11.73; S 11.79. C H N Si S . Calculated,
3
7
2
2 1
1
1
%: C 15.12; N 11.76; S 13.44.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 75 No. 7 2005

N,N -BIS(TRIETHOXYSILYLMETHYL)THIOCARBAMIDE
1093
Sorption of Ag(I) with polymers I and II. Poly-
mer I or II, 0.05 g, was stirred for 2 h at room
Kirillov, A.I., Belousova, L.I., Vlasova, N.N., and
Voronkov, M.G., Dokl. Ross. Akad. Nauk, 2003,
vol. 389, no. 6, p. 768.
temperature with 50 ml of a solution of AgNO ,
3
1
+
containing 0.01 0.2 mg ml Ag . The acidity of the
medium was varied from neutral (pH 7) to strongly
4
. Budanov, V.V. and Makarov, S.V., Khimiya sero-
soderzhashchikh vosstanovitelei (Chemistry of Sulfur-
containing Reducers), Moscow: Khimiya, 1994.
acidic (3.0 M HNO ). After the process had been com-
3
plete, the polymer was filtered off, and the filtrate was
analyzed for Ag+ by spectrophotometry with Di-
5. Vlasova, N.N., Raspopina, O.Yu., Pozhidaev, Yu.N.,
and Voronkov, M.G., Zh. Obshch. Khim., 2002,
vol. 72, no. 1, p. 61.
thizone [14], and the analysis results were used to
estimate the recovery of Ag(I) and statistical sorption
capacity.
6. Vlasova, N.N., Pestunovich, A.E., and Voron-
kov, M.G., Izv. Akad. Nauk SSSR, Ser. Khim., 1982,
no. 10, p. 2380.
Reaction of polymers I and II with potassium
permanganate. Solutions of KMnO in neutral (pH 7),
4
7
. Voronkov, M.G., Pestunovich, A.E., Sterenberg, B.Z.,
Pusechkina, T.A., and Vlasova, N.N., Z. Chem., 1983,
vol. 23, no. 7, p. 248.
acidic (0.05 M H SO ), and alkaline (0.05 M NH OH)
2
4
4
media were studied. A solution, 50 ml, containing
10 mg of Mn(VII) was sirred at room temperature for
2
h with 0.1 g of polymer I or II. A dark brown
8. Vlasova, N.N., Stanevich, L.M., Kirillov, A.I., and
Voronkov, M.G., Izv. Sib. Otd. Akad. Nauk SSSR, Ser.
Khim. Khim. Nauk, 1987, issue 1. no. 2, p. 107.
precipitate formed and was filtered off, dried in a
vacuum dessicator, and weighed. The weight of
MnO was determined by the weight of the precipitate
minum the weight of the polymer.
2
9. Kharitonov, Yu.Ya. and Prokof’eva, I.V., Dokl. Akad.
Nauk SSSR, 1965, vol. 162, no. 4, p. 829.
1
1
0. Vlasova, N.N., Raspopina, O.Yu., Kashik, T.V., and
Voronkov, M.G., Zh. Obshch. Khim., 2000, vol. 70,
no. 10, p. 1754.
ACKNOWLEDGMENTS
The work was financially supported by the Leading
Scientific Schools Program (grant no. NSh-1129-
1. Vlasova, N.N., Grigor’eva, O.Yu., and Voron-
kov, M.G., Zh. Obshch. Khim., 2001, vol. 71, no. 12,
p. 2057.
2
003.3).
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RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 75 No. 7 2005