New silatranes possessing urea functionality: Synthesis, characterization and their structural aspects

Article abstract of DOI:10.1016/j.jorganchem.2010.12.039

The present work aims at the synthesis of various novel silatranes bearing substituted urea functionality. Nucleophilic addition of various amines (morpholine, aniline, ethylenediamine and 3-aminopropyltriethoxysilane) to 3-isocyanatopropyltriethoxysilane

Full text of DOI:10.1016/j.jorganchem.2010.12.039

Journal of Organometallic Chemistry 696 (2011) 1341e1348
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
New silatranes possessing urea functionality: Synthesis, characterization
and their structural aspects
c
,
c
a
c
*
Jugal Kishore Puri , Raghubir Singh , Varinder Kaur Chahal , Raj Pal Sharma ,
b
b
Jörg Wagler , Edwin Kroke
Department of Chemistry, G.H.G. Khalsa College, Gurusar Sadhar, India
Institut für Anorganische Chemie, Technische Universität Bergakademie, Freiberg 09596, Germany
Department of Chemistry, Panjab University, Chandigarh 160 014, India
a
b
c
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 21 October 2010
Received in revised form
The present work aims at the synthesis of various novel silatranes bearing substituted urea functionality.
Nucleophilic addition of various amines (morpholine, aniline, ethylenediamine and 3-amino-
propyltriethoxysilane) to 3-isocyanatopropyltriethoxysilane resulted in the four triethoxysilanes; N-[3-
6
December 2010
(
(
triethoxysilyl)propyl]morpholine-4-carboxylic acid amide (1), 1-[3-(triethoxysilyl)propyl]-3-phenylurea
2), 1,2-bis{N -[3-(triethoxysilyl)propyl]ureido}-ethane (3) and N-[3-(triethoxysilyl)propyl]-N -[3-(tri-
Accepted 8 December 2010
0
0
ethoxysilyl)propyl]urea (4), respectively. In the presence of a base the resulting silanes undergo
transesterification reaction with triethanolamine, thus forming the corresponding silatranes, N-(3-sila-
Keywords:
N-(3-silatranylpropyl)morpholine-4-
carboxylic acid amide
0
tranylpropyl)morpholine-4-carboxylic acid amide (5), 1-(3-silatranylpropyl)-3-phenylurea (6), 1,2-Bis[N -
0
0
(3-silatranylpropyl)ureido]-ethane (7) and N-(3-silatranylpropyl)-N -(3-silatranylpropyl)urea (8),
N-[3-silatranylpropyl]-N -[3-
silatranylpropyl]urea
respectively. Among these are four novel compounds (5e8), which were characterized by elemental
0
1
13
29
1
,2-bis{N -[3-silatranylpropyl]ureido}-
analysis, IR, multinuclear ( H, C and Si) NMR and mass spectroscopy. Structures of compounds 5 and 6
were deduced by X-ray crystallography. Single crystal X-ray studies revealed distorted trigonal bipyra-
midal coordination about Si in 5 and 6 with SieN bond distance of 2.121(1) Å and 2.189(2) Å, respectively.
Ó 2011 Elsevier B.V. All rights reserved.
ethane
-(3-silatranylpropyl)-3-phenylurea
Silatrane
1
1. Introduction
receptors due to their potential to bind transition metal ions with
simultaneous formation of hydrogen bonds with anions. These are
Research on substituted ureas is a continuously growing field in
chemistry due to the importance of urea functional group in a wide
range of biological compounds such as enzyme inhibitors [1] and
pseudopeptides [2]. Substituted ureas are widely applied in
chemical industry, especially pesticides [3] and pharmaceuticals
good candidates for metal chelation because in these bitopical
ligands, urea group can act as hydrogen bond donor and/or
acceptor [18].
A large number of silatranes with different groups present at
axial position are known. Apparently, crystal structures of sila-
tranes having urea-functionalized substituents in the axial position
have not been reported yet. In previous studies, it was shown that
urea moieties could also act as mono- or bidentate ligands in the
coordination sphere of silicon [19e21]. We have now shown that
urea-functionalized triethoxysilanes can be transformed into sila-
tranes despite the presence of this potential competitor.
In continuation of our work on hypervalent silicon chemistry
[22,23], we have devoted our considerable attention to the use of
3-isocyanatopropyltriethoxysilane as a precursor for the synthesis of
some new silatranes. Herein, we synthesized a series of substituted
triethoxysilanes (1e4)by reacting3-isocyanatopropyltriethoxysilane
with different amines (morpholine, aniline, ethylenediamine and
[4]. During the past decade, a considerable amount of academic-
and industrial-based research has been carried out with the aim of
developing new trialkoxysilanes with substituted urea moiety.
Such silanes have been used to prepare new xerogels [5], hybrid
materials [6e12] and functionalized mesoporous silicas [13]. Some
solegel procedures for preparing xerogels containing arch fixed
urea functional groups in the surface layer have also been reported
[14]. Urea functional groups are efficient in recovery and separation
of rare-earth metal ions [15], in preparation of membranes [16] and
wear-resistant protective coatings on the surface of lenses made of
organic polymers [17]. Urea based ligands can act as anion
3-aminopropyltriethoxysilane), respectively. These were further
reacted with triethanolamine in the presence of different catalysts to
form corresponding silatranes (5e8). All the compounds were
*
Corresponding author. Tel.: þ91 9814522681.
E-mail address: prof_jkpuri@yahoo.com (J.K. Puri).
0
022-328X/$ e see front matter Ó 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2010.12.039

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J.K. Puri et al. / Journal of Organometallic Chemistry 696 (2011) 1341e1348
analyzed by using elemental analysis, IR, NMR and Mass spectrom-
etry. Furthermore, the molecular structures of 5 and 6 were deduced
by using X-ray crystallography. A detailed description of fragmenta-
tion pattern of silatranes 5e8 is also provided.
was not successful in the presence of KOH (Scheme 2). Therefore,
a strong base was used to obtain the product. Silanes 3 and 4 contain
two triethoxysilyl groups; therefore, the corresponding silatranes (7
and 8) contain two silatranyl moieties, whereas, 5 and 6 contain one
silatranyl moiety. All of these compounds are very stable in air and
highly soluble in common organic solvents.
2
. Results and discussion
2.1. Synthesis
2.2. Spectroscopic studies
A typical procedure for the synthesis of substituted ureas
2.2.1. IR spectroscopy
involves treatment of alkyl isocyanates with primary or secondary
amines in organic solvent [24]. In the presence of transition metal
catalysts, selenium [25] or sulfur [26] compounds, symmetrical,
unsymmetrical and even cyclo-ureas can be prepared by reacting
primary amines or ammonia with carbon monoxide.
It is known that carbofunctional organosilicon isocyanates
readily react with amines or diamines in a highly exothermic
manner. Therefore, to prepare trifunctional silanes containing
a urea functional group > NC(]O)N<, reaction of primary and
secondary amines with 3-isocyanatopropyltriethoxysilane has
been carried out. It is known that 3-isocyanatopropylsilanes are
more reactive than isocyanatomethylsilanes.
IR spectra exhibit absorption bands characteristic of both >NC
(]O)N< and silatranyl moiety. These bands are assigned by
comparing with the spectra of starting materials [29]. Bands
ꢀ1
observed in the region of 3400-3000 cm are assigned to asym-
metric and symmetric NH stretching modes, whereas CeH
stretching vibrations of methylene and methyl groups are observed
ꢀ1
in the region 3000e2800 cm . The >C]O stretching vibrations are
ꢀ
1
observed at 1650e1619 cm , relatively low values, which are
reasoned by C]O bond weakening due to the resonance involved in
NHC(]O)NH moiety. Strong bands present in the regions
ꢀ
1
1550e1150 cm
are assigned to asymmetric and symmetric
group. SieO stretching vibration is
deformations of NH and CH
2
ꢀ1
Herein,
a
known N-(3-(triethoxysilyl)propyl)morpholine-
assigned to the bands present in 1100e1080 cm region. In addi-
tion, symmetric deformational vibration of the silatranyl skeleton
with a predominant contribution from the SieN bond is observed in
4
-carboxylic acid amide (1) [27] was prepared by a new method,
whereas the other triethoxysilanes (2e4) were synthesized
according to a method published earlier (Scheme 1). The method of
preparation is found to be advantageous because of high yields of
desired products as well as no need of further purification [28,29].
In the present work, silatranes (6e8) were synthesized by trans-
esterification reaction of the corresponding triethoxysilane with
triethanolamine in the presence of KOH. By contrast, silatrane 5 was
obtained in the presence of sodium ethoxide catalyst, as this reaction
ꢀ1
the region 590e579 cm . All bands observed for silatranyl moiety
are consistent with previous literature reports [23].
2.2.2. NMR spectroscopy
Multinuclear ( H, 13C and 29Si) NMR spectra of 2e4 are consis-
1
1
tent with the literature [28,29]. It is noteworthy that H NMR
spectra of compounds 5e8 at room temperature are quite different
Scheme 1. Reaction pathway for the synthesis of triethoxysilanes (1e4).

J.K. Puri et al. / Journal of Organometallic Chemistry 696 (2011) 1341e1348
1343
Scheme 2. Reaction pathway for the synthesis of silatranes (5e8).
from their parent compounds with two intense triplets as the
characteristic feature (due to protons of OCH2, 3.75e3.78 ppm and
pattern resemble with N-alkylamides. Compound 1 shows molec-
ular ion peak as well as a peak at m/z 289 due to loss of one of the
ethoxy groups. In compound 6, only molecular ion peaks, 374
(M þ Na), 390 (M þ K), along with an additional peak at 725
NCH2, 2.80e2.83 ppm of Si(OCH
2
CH
2
)
3
N moiety). Interestingly,
rather than producing a triplet the ꢀCH
2
NH proton resonances split
up into a multiplet (region 2.66e2.87 ppm) due to their additional
coupling with adjacent eNH proton, which is also validated by
(2M þ Na) are observed. Compound 7 may undergo
a
and
cleavage (C1), very
weak fragment ion A may be formed, which eliminates NHCO to
give a peak at m/z 302. In case of cleavage (C2), two fragments
may form, a fragment with m/z 360 is observed and the other loses
one arm eOCH CH e of tricyclic silatranyl ring to form a new
b
cleavage, which is shown in Scheme 3. After a
a triplet splitting of the eNH proton resonance. A triplet for SiCH
protons appears up field due to direct SieC bond. In addition,
a multiplet due to protons of CCH C is also observed.
C NMR spectra for all compounds are consistent with their
structures. Compound 1 shows two peaks at 17.8 and 57.9 ppm due
2
b
2
13
2
2
fragment with m/z 172. The presence of covalent SieN bond in this
fragment is supported by literature [32]. The other main feature
13
to CH
peaks observed in region 57.6e58.0 and 51.0e55.4 are assigned to
silatranyl OCH and NCH , respectively. Most shielded carbon, i.e.,
SieCH is observed around 13.0 ppm, whereas the notably less
shieled >C]O is observed in the region 156.0e158.7 ppm. Other
peaks due to CH CH NH are observed in the region 24.7e25.1 and
1.8e43.6 ppm, respectively. A peak due to CH NH is shifted
downfield due to presence of adjacent >C]O group. In compound
, two additional peaks due to NCH and OCH groups of mor-
3
and OCH
2
, respectively. In the C NMR of silatranes 5e8,
observed in the spectrum of 7 is
a cleavage along with rearrange-
2
2
ment of one hydrogen. Two simultaneous rearrangements, R1 and
R2, are possible from both sides of >C]O group (Scheme 4).
Rearrangement of H away from silatranyl part (R1) may lead to
removal of 3-isocyanatopropylsilatrane with the subsequent
formation of a fragment with m/z 319. Whereas, rearrangement of
H towards silatranyl part (R2) results in B, which undergoes further
cleavage to form a fragment with m/z 202.
2
2
2
4
2
5
2
2
pholine ring are observed at 44.0 and 67.0 ppm, respectively. In
compound 6, aromatic carbons are also observed which show
chemical shift in 120.7e139.2 ppm region. Compound 7 shows
The fragmentation patterns of compounds 5 and 8 involve rear-
rangement R1, which results in aminopropylsilatranyl cation
(m/z ¼ 233). On the other hand, cleavage at
a fragment having m/z 216, which in turn loses one of the OCH
arm to form a bicyclic fragment with alkyl chain (m/z ¼ 172). Homo-
lytic cleavage of SieCH forms a silatranyl fragment with direct SieN
b
(C2) gives rise to
additional peaks due to NCH
2
CH
2
N moiety, which are also shifted
2 2
CH e
downfield as compared to silatranyl NCH
2
.
2
9
Si NMR spectra of the silatranes 5e8 exhibit the characteristic
2
up field-shifted resonance at about ꢀ67 ppm, representative for
covalent bond (at m/z ¼ 174), which is a general feature found in most
of the silatranes. This fragment also loses one arm to form bicyclic
moiety (m/z ¼ 132). Along with a very intense peak due to protonated
alkyl-substituted silatranes [22,30,31].
2.2.3. Mass spectroscopy
triethanolamine (m/z ¼ 150), most abundant peak at m/z ¼ 192 is also
þ
Mass spectra of all compounds show their respective molecular
observed due to the formation of siltranyl adduct with NH
4
, which is
ion peaks with addition of H, Na and K, and their fragmentation
also a general feature of silatrane fragmentation (Scheme 5).

1344
J.K. Puri et al. / Journal of Organometallic Chemistry 696 (2011) 1341e1348
Scheme 3. Mass fragmentation pattern of compound 7 showing possible cleavages.
Scheme 4. Mass fragmentation pattern of 7 showing rearrangements and cleavages.

J.K. Puri et al. / Journal of Organometallic Chemistry 696 (2011) 1341e1348
1345
Scheme 5. Mass fragmentation pattern of compounds 5 and 8.
2
.3. X-ray crystallography
the sum of the van der Waals radii and indicate a weak bonding
interaction between both atoms. Any effect of eNHC(]O)NH group
is not observed on the SieN bond distance due to presence of
Colorless crystals suitable for X-ray analysis were grown from
concentrated solutions of 5 and 6 in acetone. Single crystal X-ray
diffraction study has shown that both compounds crystallize in
2 2 2
intervening eCH eCH eCH e alkyl chain. The bond angle
NeSieCax is found to 178.85(4) and 179.18(9) for 5 and 6,
respectively.
ꢁ
ꢁ
1
a monoclinic crystal system (space group ¼ P2 /c). The ORTEP view
of 5 and 6 with atomic labeling (thermal ellipsoids are drawn at 50%
probability) is shown in Fig. 1 and Fig. 2, respectively. Details of
X-ray data collection and structure refinement, and selected bond
distances and angles of both compounds are listed in Table 1 and 2,
respectively. These compounds possess usual silatrane skeleton
containing Si atom in distorted trigonal bipyramidal geometry
because of the coordination of tripodal triethanolamine ligand. The
The bond angles around Si atom can be discussed in terms of
pentacoordination character i.e. percentage trigonal bipyramidal (%
TBP). The pentacoordination character may be calculated from
three apical-to-equatorial bond angles of three equatorial-to-
equatorial bond angles. %TBPax and %TBPeq for compound 5 are
67.6% and 89.7%, whereas for compound 6 are 65.4% and 87.5%,
respectively as found according to the equations given below.
2 2 3
trianionic N(CH CH Oe) entities act as tetradentate ligands coor-
ꢁ
ꢁ
ꢁ
dinating each to Si to form five membered rings, so that the
transannular SieN bond is formed. Due to this bond, Si achieves
a coordination number of five with trigonal bipyramidal coordi-
%TBPax ¼ 100% [109.5 ꢀ 1/3(S
q
n
)/109.5 ꢀ 90.0 )]
ꢁ
ꢁ
ꢁ
%TBPeq ¼ 100% [120.0 ꢀ 1/3(S
4
n
)/120.0 ꢀ 109.5 )]
2
9
nation sphere (which persists in solution, as indicated by Si NMR
spectroscopy). The O atoms of the tetradentate ligand occupy
equatorial positions and the N donor is present at apical site trans
to the urea-functionalized alkyl chain.
Where
Where
q
4
n
is average of angles OeqeSieCax
n
is average of angles OeqeSieOeq
The OeSieO bond angles can be discussed in terms of progress
of transition from a tetrahedral Si-coordination sphere towards
trigonal bipyramidal coordination (%TBP). According to the equa-
The most noteworthy (because quite variable) parameter is the
SieN bond length, which is 2.121(1) Å and 2.188(2) Å for 5 and 6,
respectively. These SieN bond distances are noticeably shorter than
ꢁ
ꢁ
tion %TBP ¼ 100% [(S OeSieO angles)ꢀ(3 109.47 )/(3 120 )ꢀ(3
Fig. 1. ORTEP view of 5 (thermal ellipsoids drawn at 50% probability).
Fig. 2. ORTEP view of 6 (thermal ellipsoids drawn at 50% probability).

1346
J.K. Puri et al. / Journal of Organometallic Chemistry 696 (2011) 1341e1348
Table 1
X-ray crystal data and structure refinement of 5 and 6.
Compound 5
Si
345.48
150(2)
Compound 6
16 25 3 4
C H N O Si
351.48
150(2)
Empirical formula
Formula weight
T (K)
C
14
H
27
N
3
O
5
l(Å)
0.71073
0.71073
Crystal system, space group
Monoclinic, P2
1
/c
1
Monoclinic, P2 /c
Unit cell dimensions
a (Å)
b (Å)
6.6310(2)
16.7435(5)
15.1252(4)
97.737(2)
1664.01(8)
4
10.1758(8)
7.4198(4)
23.3010(16)
100.350(4)
1730.7(2)
4
c (Å)
ꢁ
b
( )
3
V (Å )
Z
3
r
calc(Mg/m )
1.379
0.170
1.349
0.161
(mm 1)
ꢀ
m
MoK
a
F(000)
744
752
Crystal size (mm)
Limiting indices
Reflections collected
0.50 ꢂ 0.40 ꢂ 0.20
ꢀ10 ꢃ h ꢃ 5, ꢀ26 ꢃ k ꢃ 26, ꢀ24 ꢃ l ꢃ 24
26439
0.22 ꢂ 0.20 ꢂ 0.15
ꢀ11 ꢃ h ꢃ 11, ꢀ8 ꢃ k ꢃ 8, ꢀ27 ꢃ l ꢃ 27
13362
Unique
7323 [R(int) ¼ 0.030]
2873 [R(int) ¼ 0.058]
ꢁ
q
max ( )/completeness (%)
35.0/100
25.0/94.4
Absorption correction
Refinement method
Data/restraints/parameters
GoF on F2
Semi-empirical from equivalents
Full-matrix least-squares on F2
7323/0/212
None
Full-matrix least-squares on F2
2873/12/252
1.049
1.072
R [I > 2
s
(I)]
R
R
1
¼ 0.0393, wR
2
2
¼ 0.1036
¼ 0.1104
R
R
1
¼ 0.0786, wR
2
2
¼ 0.2068
¼ 0.2206
R(all data)
1
¼ 0.0601, wR
1
¼ 0.0999, wR
Largest diff. peak and hole (e Åꢀ3)
0.467 and ꢀ0.260
0.463 and ꢀ0.560
ꢁ
1
09.47 )] the NeSi bonds in 5 and 6 have flattened O
3
Si tetrahedral
the data set of 5 (expected transmission ratio Tmin/Tmax ¼ 0.95). The
structures were solved by direct methods (SHELXS-97) and refined
with full-matrix least-squares method (refinement of F against all
face towards an equatorial plane to an extent of %TBP ¼ 88.7% and
2
8
3
3
3
7.0%, respectively.
. Experimental
.1. General details
reflections with SHELXL-97) [33,34]. All non-hydrogen atoms were
anisotropically refined, whereas C-bound H-atoms were refined
isotropically in idealized positions (riding model). The N-bound
H-atom in the structure of 5 was located as a residual electron
density peak and refined isotropically without restraints, whereas
in the structure of 6 the N-bound H-atoms were refined isotropi-
.1.1. Synthesis
2
All the syntheses were carried out under a dry nitrogen atmo-
cally in idealized positions for sp nitrogen.
sphere using vacuum glassline. The organic solvents used were
dried and purified according to standard procedures and stored
under nitrogen. 3-Aminopropyl(triethoxy)silane (Aldrich), 3-iso-
cyanatopropyltriethoxysilane (Acros organics) and triethanolamine
The structure of compound 5 did not reveal any effects of disorder
or twinning, thus the quality of the crystal allowed for data collection
Table 2
ꢁ
Selected bond lengths (Å) and angles ( ) of 5 and 6.
(
(
Merck) were used as received from supplier. Ethylenediamine
Merck), aniline (Merck) and morpholine (Merck) was distilled by
Parameter
X-ray crystal data
refluxing over KOH pellets under dry nitrogen atmosphere.
5
6
N(1)eSi
C(7)eSi
C(9)eN(2)
C(10)eN(2)
O(1)eSi
O(2)eSi
O(3)eSi
C(10)eN(3)
C(10)eO(4)
C(11)eN(3)
C(7)eC(8)
C(8)eC(9)
O(1)eSieO(2)
O(1)eSieO(3)
O(2)eSieO(3)
C(8)eC(7)eSi
C(9)eC(8)eC(7)
C(8)eC(9)eN(2)
N(2)eC(10)eN(3)
C(10)eN(2)eC(9)
C(10)eN(3)eC(11)
N(2)eC(10)eO(4)
N(3)eC(10)eO(4)
N(1)eSi(1)eC(7)
2.121 (1)
1.883 (1)
1.456 (1)
1.348 (1)
1.670 (1)
1.670 (1)
1.684 (1)
1.386 (1)
1.229 (1)
1.461 (1)
1.534 (1)
1.522 (1)
119.87 (4)
119.61 (4)
116.95 (3)
115.83 (7)
111.90 (8)
114.05 (8)
117.17 (8)
121.28 (8)
113.48 (8)
122.05 (8)
120.75 (9)
178.85 (4)
2.189 (2)
1.877 (2)
1.448 (3)
1.340 (3)
1.651 (2)
1.654 (2)
1.662 (2)
1.375 (3)
1.246 (2)
1.395 (3)
1.530 (3)
1.530 (3)
118.17 (15)
118.06 (14)
119.47 (16)
113.97 (14)
112.69 (17)
113.64 (17)
115.21 (19)
123.35 (18)
125.13 (18)
122.60 (2)
3
.1.2. Characterization
Infrared spectra were routinely obtained as thin films or Nujol
mulls and KBr pellet on a PerkineElmer RX-I FT IR Spectropho-
tometer. Mass spectral measurements (ESI source with capillary
voltage, 2500 V) were carried out on a VG Analytical (70-S) spec-
trometer. C, H and N analyses were obtained on a PerkineElmer
Model 2400 CHN elemental analyzer and Si was estimated gravi-
ꢁ
metrically. The solution NMR spectrawererecorded at 25 C on a Jeol
FT NMR (AL 300 M Hz) and Bruker Avance II FT NMR (AL 400 MHz)
spectrometers ( H, C) and a Bruker DPX 400 spectrometer (29Si)
1
13
using CDCl
relative to internal CDCl
3
as the solvent. Chemical shifts in ppm were determined
and external tetramethylsilane (TMS).
3
3
.1.3. X-ray crystallography
Single-crystal X-ray structure analyses were carried out on
a Bruker X8 APEX II CCD diffractometer using Mo K -radiation
¼ 0.71073 Å). Whereas for the small crystal of compound 6 with
rather uniform dimensions (expected transmission ratio Tmin
max ¼ 0.99) redundant reflections were merged without absorp-
tion correction, a multi-scan absorption correction was applied to
a
(l
/
122.22 (19)
179.18 (9)
T

J.K. Puri et al. / Journal of Organometallic Chemistry 696 (2011) 1341e1348
1347
athigherangle, whereasthecrystalstructure of6 isdisturbed by both
disorder of the silatrane moiety (s.o.f. 0.731(5) and 0.269(5)) and
twinning(BASFrefined to 0.423(2)). Therefore, thedata set forcrystal
room temperature for 24 h. After that, the solvent was evaporated
under vacuum and white solid separate out which was stored
ꢁ
under nitrogen. (M.p. 140e143 C, yield: (1.95 g, 89%). IR (KBr
ꢀ
1
of 6 (exhibiting significantly lower diffraction power) was collected
plates, Nujol, cm ): 730 s, 769 s (
915 m ( NC ), 958 m ( CeC), 1007 s br, (
SieO), 1102 vs ( CeO), 1166 w ( CH O), 1263 m br (
CH N), 1389 w, 1444 w ( CH C), 1577 m ( NH), 1624 vs (
2826 s, 2974 ( CH ), 3336 b ( as NH).
n
s
SieO), 793 m, 890 w (
), 1079 vs (
CH O) (
n CeN),
ꢁ
up to
q
¼ 25 . A HKLF5 format data set was generated in WinGXupon
n
s
3
n
n
as NC
3
n
as
identification of the twin law (1 0 0)(0 ꢀ 1 0)(ꢀ0.83 0 ꢀ 1), which
n
s
2
u
2
u
ꢁ
corresponds to a 180 rotation about direct axis 10 0, using ROTAX as
2
d
3
d
n C]O),
implemented in WinGX [35,36]. For twin refinement only separated
and overlapping reflections were considered. Partly overlapping
reflections, inclusion of which would have caused refinement of
a lower BASF and therefore generated a worse structure model, were
omitted (in the procedure, which generated the HKLF5 data file).
Hence, only 94.4%of the datawere usedintherefinementforthe sake
of structure quality and better bond precision.
n
s
2
n
s
NH) (n
0
3.2.4. N-[3-(Triethoxysilyl)propyl]-N -[3-(triethoxysilyl)
propyl]urea (4)
3-isocyanatopropyltriethoxysilane (1 g, 4 mmol) was dissolved in
10 ml of ethanol, and a solution of 3-aminopropyltriethoxysilane
(0.95 g, 4 mmol) in 10 mL of ethanol, was added dropwise with
vigorous stirring. An exothermic reaction occurred. After stirring for
2 h at room temperature, the contents were refluxed for 1 h. The
solvent was evaporated under vacuum, which afforded a white solid.
As to the disorder, the silatrane moiety of 6 is disordered by
means of alternative directionalities of the propeller tilt of the
CH
CH
2
CH
CH
2
O groups. Thus, only 1 s.o.f. was refined, as the three
O groups would have to form an almost C symmetric
ꢁ
ꢀ1
2
2
3
(M.p. 55 C,yield:1.59g,84%). IR(KBrplates, Nujol,cm ):739s, 782s
SieO), 813 m, 861 w ( CeN), 915 m ( NC ), 957 m ( CeC),1015 s,
1058 s ( ),1080 vs ( as SieO),1135 vs ( CeO),1166 m ( CH O),
1255 m ( O),1317 m ( CH N), 1390 w, 1419 w ( CH C),1576 m (
NH), 1630 vs ( C]O), 2926 s, 2974 ( CH ), 3346 b ( NH) (
propeller for steric reasons, and refinement of 6 was restrained to
same bond lengths (SADI instruction) for corresponding bonds of
the two disordered parts. Thus, only bond lengths for the
predominant part are reported, as the same values were obtained
for the alternative part.
(n
s
n
n
n
s
3
n
n
nas NC
3
s
2
u
CH
2
u
2
d
3
d
n
n
s
2
n
s
nas NH).
3
.3. Synthesis of silatranes
.3.1. N-(3-silatranylpropyl)morpholine-4-carboxylic acid amide
3
3
.2. Synthesis of silanes
3
.2.1. N-(3-(triethoxysilyl)propyl)morpholine-4-carboxylic acid
(5)
amide (1)
Morpholine (1.05 g, 12.1 mmol) was dissolved in CHCl
-isocyanatopropyltriethoxysilane (3 g, 12.1 mmol) was slowly
added. The mixture was stirred and heated at 80 C for 5 h. After
cooling the contents, the solvent was evaporated under vacuum
and a light yellow oil was obtained. Yield: (3.33 g, 82.0%). IR (KBr
The compound was prepared by adding triethanolamine (0.45 g,
3
and
3.0 mmol) to 1 (1.0 g, 3.0 mmol) with simultaneous addition of
catalytic amount of sodium ethoxide in benzene (50 mL). The
contents were refluxed for 5 h in a flask fitted with DeaneStark
apparatus. The solvent was evaporated under vacuum and 10 mL of
ether was added. The contents were stirred for 30 min and product
was isolated as a white powder. Solid was filtered and dried under
3
ꢁ
ꢀ
1
plates, Neat, cm ): 792 s (
57 m ( CeC), 997 w (
166 m ( CH O), 1269 m (
w ( CH C), 1530 m ( NH), 1640 vs (
346 b ( NH) ( as NH); H NMR (300 MHz, CDCl
t, 2H, SiCH , J ¼ 6.90 Hz), 1.44 (q, 2H,
, J ¼ 8.40 Hz), 1.04 (t, 9H, CH
CCH NH, J ¼ 12.60 Hz), 3.17 (t, 4H,
C, J ¼ 8.40 Hz), 3.04 (q, 2H, CH
NCH ), 3.47 (t, 4H, OCH ), 3.63 (q, 6H, OCH
, J ¼ 14.10 Hz), 5.24 (t,
H, NH); C NMR (75.57 MHz, CDCl ): 7.27 (SiCH ), 17.78 (CH ),
3.00 (CCH C), 42.77 (HNCH ), 44.34 (CH N), 57.86 (OCH
morph, 157.60 (C]O); Si NMR (79.5 MHz, CDCl ):
n
s
SieO), 860 w (
), 1080 vs ( as SieO), 1108 vs (
CH O), 1295 m ( CH N), 1347 w, 1438
C]O), 2974 s, 2931 ( CH ),
): (ppm); 0.44
n
CeN), 913 m (
n
n
s
NC
CeO),
3
),
ꢁ
9
1
n
s
3
n
n
as NC
u
3
n
vacuum. (M.p. 175e177 C, yield 0.81 g, 78.0%). Anal. Calcd for
2
2
u
2
14 27 3 5
C H N O Si: C, 48.67; H, 7.88; N,12.16; Si, 8.13. Found: C, 48.01; H,
ꢀ
1
d
d
n
n
s
2
7.54; N,11.89; Si, 8.02. IR (KBr pellet, cm ): 590 m
776 s ( SieO), 830 m, 863 w ( CeN), 913 m (
CeC), 992 w,1023 s, ( ), 1089 vs (
1181 m ( CH O), 1257 m ( CH O), 1304 m (
w ( CH C), 1538 m ( NH), 1648 vs ( C]O), 2888 s, 2931 (
3360 b ( NH) ( as NH); H NMR (400 MHz, CDCl ): (ppm); 0.37 (t,
2H, SiCH C, J ¼ 7.84 Hz), 2.74 (t, 6H,
, J ¼ 7.81 Hz), 1.55 (m, 2H, CCH
NCH NH, J ¼ 11.94 Hz), 3.25 (t, 4H,
, J ¼ 5.82 Hz), 3.16 (q, 2H, CH
CH N), 3.60 (t, 4H, OCH ), 3.69 (t, 6H, OCH
NH); C NMR (100.62 MHz, CDCl ): 12.92 (SiCH
3.39 (CH NH), 43.96 (CH morph), 51.03 (NCH
66.60 (CH
ꢀ66.8. MS: m/z (relative abundance: %, assignment): 132 (20), 150
(41), 172 (74), 174 (18), 192 (25), 216 (11), 233 (43), 346 (100,
n
(Si ) N), 717 s,
NC ), 944 m (
CeO),
N), 1355 w, 1458
CH ),
1
3
(
s
n
3
d
n
s
n
n
s
3
n
2
3
n
as NC
3
n
as SieO), 1118 vs (
n
2
2
s
2
u
2
u
CH
2
2
2
2
d
3
n
d
n
n
s
2
1
3
1
1
2
3
d
2
3
s
n
3
d
2
2
2
2
d
), 66.85
ꢀ45.18;
2
2
2
9
(
OCH
2
)
3
2
2
MS: m/z (relative abundance: %, assignment): 289 (17.75,
2
2
2
, J ¼ 5.83 Hz), 4.86 (t, 1H,
þ
þ
13
MeOC
2
H
5
) , 357 (100, M þ Na) .
3
d
2
), 24.65 (CCH
2
C),
),
):
4
2
2
N
2
), 57.67 (OCH
2
2
9
3.2.2. 1-(3-(triethoxysilyl)propyl)-3-phenylurea (2)
2
O
morph), 158.08 (C]O); Si NMR (79.5 MHz, CDCl
3
Aniline (1.13 g, 12.1 mmol) was dissolved in CHCl
3
and 3-iso-
d
cyanatopropyltriethoxysilane (3 g, 12.1 mmol) was slowly added.
ꢁ
þ
þ
þ
The mixture was stirred and heated at 80 C for 5 h. After cooling the
M þ H) , 368 (96, M þ Na) , 713 (41, 2M þ Na) .
contents, the solvent was evaporated under vacuum and a light
brown solid was obtained. Yield: (3.55 g, 86.0%). IR (KBr plates,
3.3.2. 1-(3-silatranylpropyl)-3-phenylurea (6)
ꢀ
1
Nujol, cm ): 726 s, 770 s (
CeC), 931 m ( CeC), 1023 s (
vs( CeO),1180 m ( CH O),1260 m (
w, 1443 w ( CH C),1538 m ( NH),1630 vs (
CH ), 2972 vs ( ), 3039 w ( NH), 3224 s, 3250 s (n
n
s
SieO), 790 m, 862 w (
NC ), 1062 s ( as SieO), 1104 vs, 1133
CH O), 1316 m ( CH N),1390
C]O), 2735 s, 2942 (
as NH).
n
CeN), 908 s (
n
2.56 g (7.53 mmol) of 2 was dissolved in benzene and trietha-
nolamine (1.12 g, 7.53 mmol) was added slowly to 100 mL flask
equipped with DeaneStark apparatus. A catalytic amount of KOH
(0.2 g) was added to reaction mixture. The ethanol formed was
removed azeotropically, and the white solid was filtered under
vacuum. The solid was washed with ether (2 ꢂ 10 mL) and dried
n
n
s
3
n
n
s
2
u
2
u
2
d
3
n
d
n
n
s
2
as CH
3
n
s
0
ꢁ
3
.2.3. 1,2-bis{N -[3-(triethoxysilyl)propyl]ureido}-ethane (3)
under vacuum. (M.p. 175 C, yield 0.83 g, 80%). Anal. Calcd. for
A solution of ethylenediamine (0.24 g, 4 mmol) in 10 ml of
16 25 3 4
C H N O Si: C, 54.68; H, 7.17; N, 11.96; Si, 7.99. Found: C, 53.98; H,
ꢀ
1
ethanol was added dropwise with vigorous stirring to a solution
of 3-isocyanatopropyltriethoxysilane (2 g, 8 mmol) in 20 ml of
ethanol, cooled on an ice bath. The reaction mixture was stirred for
7.04; N, 11.23; Si, 7.11. IR (KBr pellet, cm ): 579 m
n
(Si ) N), 723 s,
CeC), 933 m ( CeC),
as SieO), 1100 vs, 1133 vs ( CeO), 1178 m (
O),1311 m ( CH N),1360 w, 1442 w ( CH C),
764 s (
1012 s (
CH
n
n
s
SieO), 813 m, 876 w (
NC ), 1053 s (
CH
n
CeN), 904 s (
n
n
s
3
n
n
s
2
h. Stirring was stopped, and the mixture was allowed to stand at
2
O), 1276 m (
u
2
u
2
d
3

1348
J.K. Puri et al. / Journal of Organometallic Chemistry 696 (2011) 1341e1348
1
555 m (
CH ), 3037 w (
CDCl ): (ppm); 0.02 (t, 2H, SiCH
J ¼ 7.80 Hz), 2.31 (t, 6H, NCH , J ¼ 5.70 Hz), 2.77 (q, 2H, CH
, J ¼ 5.70 Hz), 4.81 (t,1H, CH NH), 6.28
d
NH), 1631 vs (
NH), 3247 s, 3253 s (
, J ¼ 7.80 Hz), 1.18 (m, 2H, CCH
NH,
n
C]O), 2874 s, 2922 (
n
s
CH
2
), 2971 vs (
as NH); H NMR (300 MHz,
C,
n
as
Appendix A. Supplementary material
1
3
n
s
n
3
d
2
2
CCDC 782354 and 782353 contains the supplementary crystal-
lographic data for 5 and 6, respectively. These data can be obtained
free of charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.jorganchem.2010.12.039.
2
2
J ¼ 12.6 Hz), 3.26 (t, 6H, OCH
2
2
1
3
(
(
(
s, 1H, NHC), 6.53e6.91 (m, 5H, aromatic ring);
100.62 MHz, CDCl
CH
C NMR
C), 43.19
2
), 120.66e139.21 (aromatic
3
):
d
13.05 (SiCH
2
), 25.09 (CCH
2
2
NH), 50.95 (NCH
2
), 57.59 (OCH
2
9
ring), 155.99 (C]O); Si NMR (79.5 MHz, CDCl
3
):
d
ꢀ67.0. MS: m/z
þ
(
relative abundance: %, assignment): 374 (100, M þ Na) , 390 (5.8,
References
þ
þ
M þ K) , 725 (86, 2M þ Na) .
[
1] D.J. Kempf, K.C. Marsh, D.A. Paul, M.F. Knigge, D.W. Norbeck,
W.E. Kohlbrenner, L. Codacovi, S. Vasavanonda, P. Bryant, X.C. Wang, Anti-
microbial. Agents. Chemother. 35/11 (1991) 2209e2214.
0
3.3.3. 1,2-bis{N -[3-silatranylpropyl]ureido}-ethane (7)
A solution of 3 (1.0 g, 1.81 mmol) and triethanolamine (0.56 g,
.75 mmol) in 50 mL benzene was heated to reflux. After addition of
[2] J. Gante, Synthesis 6 (1989) 405e413.
3
[3] Y. Nakagawa, K. Kitahara, T. Nishioka, Pestic. Biochem. Physiol. 21/3 (1984)
09e325.
3
KOH(0.2 g), the ethanol formed wasdistilledoffby usingDeaneStark
apparatus. The white solid obtained was filtered, washed with ether
[4] A.G. Gilman, L.S. Goodman, A. Gilman, The Pharmacological Basis of Thera-
peutics, sixth ed. MacMillan, New York, 1980.
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Surf. 7 (2002) 35e45.
ꢁ
(
2 ꢂ 10 mL) and dried under vacuum. (M.p. 182e185 C, yield 0.73 g,
7
9
5
0%). Anal. Calcd. for C22
.74. Found: C, 44.97; H, 7.28; N,14.33; Si, 9.12. IR (KBr pellet, cm ):
87 m (Si ) N), 720 s, 764 s ( SieO), 815 m, 878 w ( CeN), 911 m
NC ), 940 m ( CeC),1017 s br, ( ),1099 vs ( as SieO),1123 vs
CeO),1188 w ( CH O) ( CH N),1355 w,1425
CH C), 1573 m ( C]O), 2876 s, 2928 ( CH ),
339 b ( NH) ( ): (ppm); 0.02 (t,
H, SiCH C, J ¼ 7.50 Hz), 3.35 (m, 4H,
, J ¼ 7.9 Hz), 1.26 (m, 2H, CCH
CH N), 2.71 (t, 6H, NCH NH,
, J ¼ 5.70 Hz), 2.87 (q, 2H, CH
J ¼ 11.73 Hz), 3.51 (t, 6H, OCH , J ¼ 5.7 Hz), 5.69 (t,1H, NH), 5.76 (t,1H,
NH); C NMR (100.62 MHz, CDCl ): 13.27 (SiCH ), 25.00 (CCH C),
1.81 (CH NH), 48.69 (NCH CH N), 55.43 (NCH ), 57.95 (OCH ),
56.99 (C]O); Si NMR (79.5 MHz, CDCl ):
ꢀ69.6. MS: m/z (rela-
tive abundance: %, assignment): 150 (100), 172 (10), 202 (7.4), 302
44 6 8 2
H N O Si : C, 45.81; H, 7.69; N, 14.57; Si,
ꢀ
1
[6] J.J.E. Moreau, L. Vellutini, M.W.C. Man, C. Bied, J. Am. Chem. Soc. 123/7 (2001)
1509e1510.
n
n
s
n
[7] J.J.E. Moreau, L. Vellutini, M.W.C. Man, C. Bied, J.L. Bantignies, P. Dieudonne,
(n
s
3
n
n
as NC
3
n
J.L. Sauvajol, J. Am. Chem. Soc. 123/32 (2001) 7957e7958.
[
[
8] V.Z. Bermudez, R.A. Sa Ferreira, L.D. Carlos, C. Molina, K. Dahmouche,
S.J.L. Ribeiro, J. Phys. Chem. B. 105/17 (2001) 3378e3386.
9] L.D. Carlos, Y. Messaddeq, H.F. Brito, R.A. Sa Ferreira, V.Z. Bermudez,
S.J.L. Ribeiro, Adv. Mater. 12/8 (2000) 594e598.
(n
s
CH
2
O),1272 m br (
u
2
u
2
w (
3
2
d
3
n
d
NH), 1623 vs (
n
n
s
2
1
s
n
as NH); H NMR (300 MHz, CDCl
3
d
[
[
10] V. Bermudez, L.D. Carlos, L. Aleacer, Chem. Mater. 11/3 (1999) 569e580.
11] L.D. Carlos, V. Bermudez, R.A. Sa Ferreira, L. Marques, M. Assuncao, Chem.
Mater. 11/3 (1999) 581e588.
2
2
NCH
2
2
2
2
2
[12] P.H. Sung, T.F. Hsu, Y.H. Ding, A.Y. Wu, Chem. Mater. 10/6 (1998) 1642e1646.
[13] O. Gona, I. Mel’nyk, Y. Zub, D. Cauzzi, G. Predieri, Abstracts of Papers, NATO
Advanced Research Workshop. Nanostructured Materials and Coatings for
Biomedical and Sensor Applications, Kyiv, Ukraine 4e8 Aug,
2002, 13.
13
3
d
2
2
4
1
2
2
2
2
2
29
3
d
[14] I.V. Mel’nik, N.V. Stolyarchuk, Y.L. Zub, A. Dabrowski, Russ. J. Appl. Chem. 79/6
(2006) 981e986.
þ
þ
(
10), 319 (11), 360 (12), 577 (31, M þ H) , 599 (58, M þ Na) .
[15] M.G. Voronkov, N.N. Vlasova, Y.N. Pozhidaev, Appl. Organomet. Chem. 14/6
(2000) 287e303.
0
[16] C. Li, T. Glass, G.L. Wilkes, J. Inorg. Organomet. Polym. 9/2 (1999) 79e106.
3.3.4. N-[3-silatranylpropyl]-N -[3-silatranylpropyl]urea (8)
[
[
17] C. Guizard, P. Lacan, New J. Chem. 18/10 (1994) 1097e1107.
18] B. Wu, X. Huang, J. Liang, Y. Liu, X.J. Yang, H.M. Hu, Inorg. Chem. Comm. 10/5
A solution of 4 (1.58 g, 3.46 mmol) and triethanolamine (1.12 g,
7.52 mmol) in benzene (50 mL) was refluxed for 4 h in a flask fitted
(2007) 563e566.
with DeaneStark apparatus. A catalytic amount of KOH (0.2 g) was
added. The precipitate was filtered off; solid was washed with ether
and dried under vacuum. (M.p. 219e221 C, yield 1.08 g, 65%). Anal.
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[
[
20] J. Wagler, A.F. Hill, Organometallics 27/24 (2008) 6579e6586.
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Eur. J. Inorg. Chem. 3 (2010) 461e467.
ꢁ
Calcd for C19
C, 46.06; H, 7.07; N, 11.23; Si, 11.03. IR (KBr pellet, cm ): 584 m
Si ) N), 719 s, 762 s ( SieO), 811 m, 878 w ( CeN), 910 m (
NC ), 940 m ( CeC), 1016 s, 1053 s ( ), 1099 vs ( as SieO),
125 vs ( CeO), 1194 m ( CH O), 1277 m ( CH O), 1312 m (
CH N), 1354 w, 1415 w ( CH C), 1573 m ( NH), 1619 vs ( C]O),
874 s, 2926 ( CH ), 3336 b ( NH) ( as NH); H NMR (300 MHz,
CDCl ): (ppm); 0.02 (t, 2H, SiCH C,
, J ¼ 8.10 Hz), 1.17 (m, 2H, CCH
J ¼ 8.10 Hz), 2.38 (t, 6H, NCH , J ¼ 6.00 Hz), 2.66 (q, 2H, CH NH,
, J ¼ 6.00 Hz), 4.16 (t,1H, NH); C NMR
13.01 (SiCH ), 25.12 (CCH C), 43.62
), 57.68 (OCH ), 158.65 (C]O); Si NMR
ꢀ66.7. MS: m/z (relative abundance: %,
H
38
N
4
O
7
Si
2
: C, 46.51; H, 7.81; N, 11.42; Si, 11.45. Found:
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(2010) 107e112.
ꢀ1
n
[23] R. Singh, J.K. Puri, V.K. Chahal, R.P. Sharma, P. Venugopalan, J. Organomet.
(
n
s
n
n
s
Chem. 695/2 (2010) 183e188.
3
n
n
as NC
3
n
[24] N.F. Woolsey, L.J. Radonovich, F.M. Saad, M. Brostrom, J. Org. Chem. 49/11
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25] N. Sonoda, T. Yasuhara, K. Kondo, T. Ikeda, S. Tsutsumi, J. Am. Chem. Soc. 93/23
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(
1
n
s
2
u
2
u
[
2
d
3
d
n
(
1
2
n
s
2
n
s
n
[
[
27] T. Matsuoka, S. Yamamoto, O. Moriya, Chem. Lett. 37/7 (2008) 772e773.
28] M. Michau, M. Barboiu, R. Caraballo, C.A. Hérault, A.V. Lee, Chem. Eur. J. 14/6
3
d
2
2
2
2
(2008) 1776e1783.
13
J ¼ 12.6 Hz), 3.33 (t, 6H, OCH
2
[29] I.V. Mel’nik, O.V. Lyashenko, Y.L. Zub, A.A. Chuiko, D. Cauzzi, G. Predieri, Russ. J.
Gen. Chem. 74/11 (2004) 1658e1664.
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Organometallics 17/4 (1998) 504.
(
(
(
100.62 MHz, CDCl
CH NH), 51.04 (NCH
79.5 MHz, CDCl ):
3
):
d
2
2
2
9
2
2
d
2
3
[31] M.S. Sorokin, M.G. Voronkov, Russ. J. Gen. Chem. 76/3 (2006) 461.
assignment): 132 (9.2), 150 (25), 192 (5.2), 233 (5.4), 491 (100), 513
[32] V. Pestunovich, S. Kirpichenko, M. Voronkov, Silatranes and their tricyclic
analogues. in: Z. Rappoport, Y. Apeloig (Eds.), Chemistry of Organic Silicon
Compounds. Wiley, Chichester, UK, 1998, pp. 1447e1537.
þ
þ
(
92, M þ Na) , 529 (21, M þ K) .
[33] SHELXS: Version 97 by G.M. Sheldrick (Universität Göttingen).
Acknowledgement
[34] SHELXL: Version 97 by G.M. Sheldrick (Universität Göttingen).
[
[
35] WinGX. Version 1.64.05 by L.J. Farrugia (University of Glasgow); L.J. Farrugia,
J. Appl. Cryst 32 (1999) 837e838.
36] ROTAX: Version 26/11/2001 by S. Parsons, R. Gould (University of Edinburgh),
R. Cooper (Oxford) and L.J. Farrugia (University of Glasgow).
Raghubir Singh is thankful to UGC, New Delhi for providing
financial support [F-4-1/2006 (BSR)].