New polyfunctional silicon-containing amines C6[CH 2CH2SiMe(OCH2CH2NR2) 2]6 (R = H, Me) and their reactions with cobalt(II) chloride and dicobalt octacarbonyl

Article abstract of DOI:10.1023/A:1022199722015

Hexakis[bis(2-aminoethoxy)methylsilylethyl]benzene and hexakis[bis(N,N-dimethyl-2-aminoethoxy)methylsilylethyl]benzene C ₆[(NR₂CH₂CH₂O) ₂SiMeCH₂CH₂]₆ (4, R = H; 5, R =

Full text of DOI:10.1023/A:1022199722015

Russian Chemical Bulletin, International Edition, Vol. 51, No. 12, pp. 2277—2285, December, 2002
2277
New polyfunctional siliconꢀcontaining amines
C6[CH2CH2SiMe(OCH2CH2NR2)2]6 (R = H, Me) and their reactions
with cobalt(II) chloride and dicobalt octacarbonyl
ꢀ
E. Yu. Ladilina, V. V. Semenov, T. G. Mushtina, M. A. Lopatin,
Yu. A. Kurskii, A. I. Kirillov, and G. A. Domrachev
G. A. Razuvaev Institute of Organometallic Chemistry, Russian Academy of Sciences,
49 ul. Tropinina, 603950 Nizhnii Novgorod, Russian Federation.
Fax: +7 (831 2) 66 1497. Eꢀmail: klarisa@imoc.sinn.ru
Hexakis[bis(2ꢀaminoethoxy)methylsilylethyl]benzene and hexakis[bis(N,Nꢀdimethylꢀ2ꢀ
aminoethoxy)methylsilylethyl]benzene C6[(NR2CH2CH2O)2SiMeCH2CH2]6 (4, R = H;
5,
C6(Cl2MeSiCH2CH2)6 and 2ꢀaminoethanol or N,Nꢀdimethylꢀ2ꢀaminoethanol, respectively.
Compounds and react with anhydrous cobalt (II) chloride to give poorly
soluble dodecachloro{hexakis[bis(2ꢀaminoethoxy)methylsilylethyl]benzene}hexacobalt
and dodecachloro{hexakis[bis(N,Nꢀdimethylꢀ2ꢀaminoethoxy)methylsilylethyl]benꢀ
R
=
Me) were prepared from hexakis(methyldichlorosilylethyl)benzene
4
5
zene}hexacobalt {Co6[(NR2CH2CH2O)2SiMeCH2CH2]6C6}Cl12 (R = H or Me), respecꢀ
tively. Polyfunctional amine 4 reacts with dicobalt octacarbonyl to produce hexaꢀ
kis[bis(2ꢀaminoethoxy)methylsilylethyl]benzenedicobalt(II) tetrakis(tetracarbonylcobaltate)
{Co2[(NH2CH2CH2O)2SiMeCH2CH2]6C6}[Co(CO)4]4. N,NꢀDimethylꢀsubstituted polyꢀ
functional amine 5 is lowly reactive in the reaction with Co2(CO)8, whereas the
simplest model of this compound, viz., bis(N,Nꢀdimethylꢀ2ꢀaminoethoxy)dimethylꢀ
silane
(NMe2CH2CH2O)2SiMe2,
slowly
reacts
with
Co2(CO)8
to
give
tris[bis(N,Nꢀdimethylꢀ2ꢀaminoethoxy)dimethylsilane]cobalt(II) bis(tetracarbonylcobaltate)
{Co[(NMe2CH2CH2O)2SiMe2]3}[Co(CO)4]2. Thermal decomposition and transformations of
the resulting complexes under the action of oxygen and water were studied.
Key words: hexakis[bis(2ꢀaminoethoxy)methylsilylethyl]benzene, hexakis[bis(N,Nꢀdiꢀ
methylꢀ2ꢀaminoethoxy)methylsilylethyl]benzene, cobalt(II) chloride, dicobalt octacarbonyl,
amine complexes, coordination polymers, hydrolysis, xerogel, thermal decomposition.
Transition metal complexes included in organosilicate
matrices are prepared by hydrolysis of coordination comꢀ
pounds containing functional organosilicon ligands.1—5
Organosilsesquioxane structures are formed by hydrolysis
of the peripheral triethoxysilyl groups of the complex comꢀ
pounds followed by condensation of the resulting silanols.
The relatively high resistance of amino derivatives of coꢀ
balt and chromium to hydrolysis enables one to form the
siloxane core, the center of the coordination compound
remaining virtually unchanged.6—8 If the ligand contains
a large number of functional groups, there is a possibility
to synthesize a polymer already in the first step through
the formation of coordination bonds. Coordination polyꢀ
mers are of interest as starting compounds for the syntheꢀ
sis of new ceramic materials and heterogeneous catalysts
and as porous structures for the ion exchange and adsorpꢀ
tion of gases and small molecules.9,10
substituents bound to these silicon atoms. The reactions
of these compounds with cobalt(II) chloride and dicobalt
octacarbonyl giving rise to coordination polymers were
studied.
Results and Discussion
Synthesis of polyfunctional siliconꢀcontaining amines
based on hexa(silylalkyl) derivatives of benzene. Hexaꢀ
kis[bis(2ꢀaminoethoxy)methylsilylethyl]benzene (4) and
hexakis[bisꢀ(N,Nꢀdimethylꢀ2ꢀaminoethoxy)methylsilylꢀ
ethyl]benzene (5) were prepared from hexakis(methylꢀ
dichlorosilylethyl)benzene (1) or hexakis(methyldiethoxyꢀ
silylethyl)benzene (2) and 2ꢀaminoethanol or N,Nꢀdiꢀ
methylꢀ2ꢀaminoethanol, respectively (see Scheme 1).
According to the earlier data,11 the adjacent substituꢀ
ents in hexa(silylalkyl) benzene derivatives are in trans
positions with respect to each other. Such an arrangement
does not hinder the formation of coordination polymers
through the terminal —NR2 groups but efficiently proꢀ
In the present study, we report a procedure for
the preparation of two new hexaalkylated benzenes
(Scheme 1), which contain six silicon atoms and 12 amino
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2115—2122, December, 2002.
1066ꢀ5285/02/5112ꢀ2277 $27.00 © 2002 Plenum Publishing Corporation

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Russ.Chem.Bull., Int.Ed., Vol. 51, No. 12, December, 2002
Ladilina et al.
Scheme 1
X = Cl (1), OMe (2), Me (3); R = H (4), Me (5)
tects the benzene ring from the attack of reagents.
Thus, permethylated compound 3 did not give benꢀ
zene tricarbonyl and bis(arene) derivatives of chromium
(Scheme 2).
and the signal of 12 O—CH2— groups of the aminoethoxy
substituents at the Si atom. The weak triplet of the
—CH2—OH methylene group is indicative of the presꢀ
ence of a small impurity of N,Nꢀdimethylꢀ2ꢀaminoꢀ
ethanol.
Reactions with cobalt(II) chloride. It is known that coꢀ
balt chloride can bind two amine molecules to form comꢀ
plexes with composition Co(NH2R)2Cl2. Previously,8,12
we have studied the reactions of cobalt(II) and chroꢀ
mium(III) chlorides with primary organosilicon amines.
These reactions proceeded rapidly with the evolution of
heat, chromium chloride being less reactive. The reactiviꢀ
ties of tertiary amines in such transformations were studꢀ
ied using bis(N,Nꢀdimethylꢀ2ꢀaminoethoxy)dimethylꢀ
silane (6) as an example. It appeared that compound 6, like
primary amines, readily reacted with CoCl2 (Scheme 3)
to give complex 7 as a very hygroscopic brightꢀblue liquid.
Scheme 2
Benzene derivatives 4 and 5 are viscous orange liqꢀ
uids, which undergo hydrolysis by atmospheric moisture.
Due to their low volatility, these compounds cannot be
subjected to vacuum distillation. Since compound 4 is
poorly soluble in saturated hydrocarbons, it can be puriꢀ
fied by washing with hexane. The 1H NMR spectrum
showed that the yield of the target product obtained after
repeated washing and prolonged heating in vacuo was
97%. Compound 5 was purified from impurities with the
use of activated carbon and prolonged heating in vacuo.
Scheme 3
CoCl2 + (NMe2CH2CH2O)2SiMe2
6
Co[(NMe2CH2CH2O)2SiMe2]Cl2
7
Polyfunctional hexaalkylated benzene derivatives 4
and 5 rather actively reacted with CoCl2 (Scheme 4). The
reactions proceeded with the heat evolution and were
completed in 30 min.
Compounds 8 and 9 are blue solids virtually insoluble
in saturated, aromatic, and chlorinated hydrocarbons and
1
The H NMR spectrum of compound 5 (see the Experiꢀ
mental section) has signals for six protons of the Me groups
at the Si atom, six SiCH2 fragments, 24 Me groups at the
N atoms, and 12 —CH2N methylene groups, which overꢀ
lap with the signal of six CH2 groups at the benzene ring

Polyfunctional siliconꢀcontaining amines
Russ.Chem.Bull., Int.Ed., Vol. 51, No. 12, December, 2002 2279
Scheme 4
Transmittance
6 CoCl2 + [(NR2CH2CH2O)2SiMeCH2CH2]6C6
4, 5
1
{Co6[(NR2CH2CH2O)2SiMeCH2CH2]6C6}Cl12
8, 9
R = H (4, 8), Me (5, 9)
2
THF and poorly soluble in acetonitrile (8) and DMF (9).
Coordination polymers are characterized9,10 by low soluꢀ
bility in organic solvents. A large number of functional
groups in the ligand (two, three, or more) and the remote
arrangement of the donor atoms (for example, on oppoꢀ
site sides of the aromatic ring) facilitate the formation of
twoꢀ and threeꢀdimensional coordination polymers.9,10
Considering that the starting compounds 4 and 5 satisfy
these conditions, the low solubility of complexes 8 and 9
can be taken as indirect evidence in favor of the polyꢀ
meric structures of the resulting compounds. The use of
dilute solutions in these reactions did not prevent the
binding of polyfunctional aminobenzenes to form coordiꢀ
nation polymers.
The IR spectra of the starting aminobenzene 4 and its
complex with cobalt chloride 8 (Fig. 1) showed that the
coordination of the primary amino groups in comꢀ
pound 4 to the cobalt(II) cation led to the shifts of the
N—H stretching bands to the lowꢀfrequency region13 by
20—70 cm–1: 4, ν(N—H) 3350, 3320, 3170 cm–1; 8,
ν(N—H) 3330, 3200, 3110 cm–1. The IR bands of the
C—H bonds of the Me groups at the N atom are shifted
upon the formation of complex 9 to the lowꢀfrequency
region by 20—130 cm–1 compared to the corresponding
bands in the IR spectrum of the initial aminobenzene 5
(2810, 2775, 2730 cm–1), and their intensities are subꢀ
stantially decreased (Fig. 2). These changes are associꢀ
3500 3000 2500
2000
1500 1000 ν/cm–1
Fig. 2. IR spectra of compound 5 (1, liquid film) and its complex
with cobalt(II) chloride 9 (2, Nujol mull).
ated with the fact that the formation of the Co—N bond
leads to a decrease in the effective negative charge on the
N atom resulting in a change in the charge on the C atom
bound to the N atom.14 The positions of the absorption
bands of the alkoxysilyl groups (4: 1250, 1110, 1090, 950,
800 cm–1; 5: 1250, 1110, 1070, 950, 890, 820, 790 cm–1),
which are not involved in the formation of coordination
bonds, remain virtually unchanged. The transformation
of the IR spectrum of compound 6 upon the formation of
the complex with CoCl2 is analogous to those described
for compounds 4 and 5.
The electronic absorption spectra of compounds 7—9
(Fig. 3) are characterized by the presence of a multiꢀ
plet with three maxima in the region from 18000 to
14000 cm–1 (7, 16700, 15800, 15200 cm–1; 8, 16800,
15900, 15200 cm–1; 9, 16600, 15800, 15200 cm–1), which
is typical of fourꢀcoordinate cobalt complexes, and this
D
D
Transmittance
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
4
1
2
3
2
4
1
3
3
40000 35000 30000 25000 20000
ν/cm–1
Fig. 3. Electronic absorption spectra of complexes 7—9: 1, a
solution of 7 in MeCN; 2, a solution of 8 in DMF; 3, a solution
of 7 in MeCN, 4, a film of compound 7 after storage in air
for 20 h.
3500 3000 2500 2000 1500 1000 ν/cm–1
Fig. 1. IR spectra of compound 4 (1, liquid film) and its complex
with cobalt(II) chloride 8 (2, Nujol mull).

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Russ.Chem.Bull., Int.Ed., Vol. 51, No. 12, December, 2002
Ladilina et al.
4
band belongs to the T1(P)—4A2 transition with a vibraꢀ
tional structure.15 The presence of additional bands is,
apparently, attributable to distortions of the tetrahedral
structure, which are most clearly manifested in the elecꢀ
tronic absorption spectrum of compound 8. The UV reꢀ
gion of the spectra of highly dilute solutions of comꢀ
pounds 8 and 9 shows an absorption band belonging to
the hexaalkylated benzene ring (39600 cm–1 for comꢀ
pound 9).
slowly, whereas the spectrum measured in a film changed
rapidly. The spectrum of the product (16200, 15800,
14900, and 14300 cm–1) is identical with the known specꢀ
tra15,16 of salts in which the doubleꢀcharged tetrahedral
[CoCl4]2– anion is bound with two R4N+ ammonium
cations (for example, the spectrum of the compound
with R = Bun shows four absorption bands at 16230,
15750, 14900, and 14300 cm–1). The observed transforꢀ
mations can be represented by a series of equations
(Scheme 5).
Compounds 7—9 are highly sensitive to atmospheric
oxygen and moisture. Compound 7 is particularly unꢀ
stable. It rapidly changed the color to green, which was
accompanied by the appearance of an intense IR band at
3360 cm–1 (Fig. 4) belonging to vibrations of the associꢀ
ated OH groups and a series of bands in the region of
2800—2400 cm–1 belonging to N—H stretching vibraꢀ
tions of the [NMe2H]+ ammonium cation. A shoulder at
1040 cm–1, which is observed on the lowꢀfrequency side
of the absorption band at 1070 cm–1 (SiOC), characterꢀ
izes the SiOSi fragments. These changes indicate that
compound 7 underwent hydrolysis to form amino alcoꢀ
hol, silanols (major products), siloxanes, and ammonium
salts. The latter were formed through the binding of hydroꢀ
gen chloride generated in the reaction of the Co—Cl fragꢀ
ment with H2O or silanol groups. The electronic absorpꢀ
tion spectral data allow one to establish the state of the
Co2+ cation characterized by the maximum intensity of
absorption bands. The visible region of the spectrum of
compound 7 (see Fig. 3, spectrum 1) has a multiplet with
Scheme 5
2 7 + 2 H2O
2 7 + 2 H2O
[Co(NMe2CH2CH2OH)4]2+[CoCl4]2–
+ 1/n HO(SiMe2O)nH
+
[Me2Si(OCH2CH2NMe2H)2]2+[CoCl4]2–
+
+ Co[(NMe2CH2CH2O)2SiMe2](OH)2
{[Co[(NMe2CH2CH2O)2SiMe2]2}2+[CoCl4]2–
2 7
According to the lastꢀlisted equation in Scheme 5, the
spontaneous rearrangement is the least probable process
because compound 7 is rather thermally stable in inert
atmosphere in the absence of atmospheric moisture.
Compounds 7, 8, and 9 were decomposed by water to
form silanol derivatives, which were subseqently converted
into polysiloxanes and formed a white gel. The latter were
subsequently converted into polysiloxanes and formed a
white gel. Complexes 7 and 9 gave hydroxides, whereas
complex 8 produced cobalt(II) chloride.
Reactions with dicobalt octacarbonyl. Primary amines
reacted with Co2(CO)8 to give cobalt(II) hexamine
bis(tetracarbonylcobaltates) [Co(NH2R)6][Co(CO)4]2.17
Generally, the reactions are accompanied by the inserꢀ
tion of CO, which is liberated in the course of the reacꢀ
tion, at the N—H bond to give formamide derivatives.
The latter compounds, like the starting amines, are bound
to the Co2+ cation. As a result, both the amino and amide
ligands are involved in the octahedral environment about
the Co2+ cation (Scheme 6).
maxima at 20500, 18000, 16700, 15800, and 15200 cm–1
,
which is typical of tetrahedral cobalt diamine dichloride
complexes. In air, complex 7 underwent chemical transꢀ
formations, as evidenced by the changes in the electronic
absorption spectrum (see Fig. 3, spectrum 4). The changes
in the spectrum recorded in solutions in MeCN occurred
Transmittance
1
2
Scheme 6
3 Co2(CO)8 + 12 NH2R
3
2 [Co(NH2R)6–x(HC(O)NHR)x][Co(CO)4]2
+
+ (8 – 2x) CO
3500 3000 2500 2000 1500 1000 ν/cm–1
Bis(N,Nꢀdimethylꢀ2ꢀaminoethoxy)dimethylsilane (6)
containing the tertiary amino groups proved to be less
active in the reaction with Co2(CO)8 (Scheme 7) comꢀ
pared to 3ꢀaminopropyltriethoxysilane studied earlier. The
Fig. 4. Transformation of the IR spectrum of a thin film of
complex 7 on exposure to atmospheric oxygen and moisture
during 5 min (1), 0.5 h (2), and 20 h (3).

Polyfunctional siliconꢀcontaining amines
Russ.Chem.Bull., Int.Ed., Vol. 51, No. 12, December, 2002 2281
Transmittance
reaction proceeded slowly. After precipitation, the yield of
tris[bis(N,Nꢀdimethylꢀ2ꢀaminoethoxy)dimethylsilane]coꢀ
balt(II) bis(tetracarbonylcobaltate) (10) was only 17%.
2
1
Scheme 7
1
1
3 Co2(CO)8 + 6 6
2 {Co[(NMe2CH2CH2O)2SiMe2]3}[Co(CO)4]2 +
2
10
2
+ 8 CO
An analogous reaction of compound 5 proceeded even
more slowly. We failed to isolate the resulting cobaltate
in pure form. By contrast, compound 4 reacted with
Co2(CO)8 rather readily to give hexakis[bis(2ꢀaminoꢀ
ethoxy)methylsilylethyl]benzenedicobalt(II) tetrakis(tetraꢀ
carbonylcobaltate) (11) (Scheme 8).
3500 3000 2500 2000 1500 1000 ν/cm–1
Fig. 6. IR spectra of compound 11 (1, Nujol mull) and xerogel
12 (2, 4000—2500 cm–1, suspension in fluorohydrocarbon oil;
2200—400 cm–1, Nujol mull).
11 is presented in Fig. 6. The complex formation has a
substantial effect on the vibrations of the groups bound to
the N atom. In the spectrum of compound 11, the stretchꢀ
ing bands (3350, 3270, 3170 cm–1) and bending bands
(1590 cm–1) of the N—H bond are shifted to the lowꢀ
frequency region by 20—30 cm–1. The presence of a small
number of amide fragments is evidenced by the lowꢀinꢀ
tensity band at 1650 cm–1 (amide I). In the spectrum of
compound 10, the absorption bands belonging to the Me
substituents bound to the N atom are shifted to the highꢀ
frequency region and coincide with the C—H stretching
vibrations in the spectra of alkanes. This is a consequence
of a higher degree of covalence of the Co—N bond in
cobalt carbonyl complexes compared to that in the comꢀ
plexes with CoCl2 (absorption band corresponding to the
vibrations ν(Co—N)18 is observed at 370 and 350 cm–1 in
the spectra of compounds 8 and 11, respectively). As a
result, no substantial decrease in the effective negative
charge on the N atom occurs.14 The spectra of cobaltates
10 and 11 are characterized by the presence of an intense
absorption band at 1870 cm–1 corresponding to the
[Co(CO)4]– anion.
Scheme 8
3 Co2(CO)8 + 4
{Co2[(NH2CH2CH2O)2SiMeCH2CH2]6C6}[Co(CO)4]4
11
+ 8 CO
The course of the reaction was monitored by CO libꢀ
eration. After 1 h, the yield of CO was 50% of the calcuꢀ
lated value, and the yield reached 95% after 15 h. Hence,
it follows that this reaction afforded the formamide deꢀ
rivative in an insignificant amount. Complexes 10 and 11
were obtained as crimsonꢀcolored powders.
The IR spectra of organosilicon amine 6 and the prodꢀ
uct of its reaction with dicobalt octacarbonyl, viz., comꢀ
plex 10, are shown in Fig. 5. The IR spectrum of cobaltate
Transmittance
1
The visible region of the electronic absorption
spectrum of compound 10 has a broad structureless
band (Fig. 7) starting from 15000 cm–1. The specꢀ
trum of cobaltate 11 shows two bands with maxima at
25400 cm–1 (ε = 392 L mol–1 cm–1) and 18700 cm–1 (ε =
545 L mol–1 cm–1). The character of the spectra and
the extinction coefficients calculated per Co(NH2R)6
group correspond to the octahedral hexaamine cobalt(II)
cation.15
2
The structures of compounds 10 and 11 contain the
Co atoms, which are in different valence states and have
different ligand environment. The carbonyl cobaltate
anions are the least thermally stable. Compound 11
withstanded thermal treatment in a sealed evacuated tube
up to 150 °C (1 h) without noticeable changes. However,
3500 3000 2500 2000 1500 1000 ν/cm–1
Fig. 5. IR spectra of compounds 6 (1, liquid film) and 10
(2, Nujol mull).

2282
Russ.Chem.Bull., Int.Ed., Vol. 51, No. 12, December, 2002
Ladilina et al.
D
9, and 10 became medium porous materials, and their Ssp
were 144, 91, and 65 m2 g–1, respectively. Powder Xꢀray
diffraction analysis revealed the following products:
8, αꢀCo (d = 2.16, 1.91 Å), βꢀCo (d = 2.04, 1.76 Å);
9, αꢀCo (d = 2.16, 1.91 Å), βꢀCo (d = 2.03, 1.76 Å),
CoCl2·2 H2O (d = 5.44, 4.23, 2.77, 2.11, 2.07, 1.76 Å);
10, elemental cobalt in the β form (d = 2.03 and 1.77 Å).
The αꢀCo : βꢀCo ratio in the products of thermal decomꢀ
position was approximately 1 : 7. The presence of silicon
dioxide was confirmed by the presence of the amorphous
halo in the reflection angle range 2θ = 15—25°.
2.0
1.6
1.2
0.8
0.4
1
It is known20 that dilute solutions of the cobalt(II)
hexamine and hexamide cobalt carbonyl comꢀ
plexes [CoAm6][Co(CO)4]2 produce carbonate
(Am = Py, DMF) or carbonateꢀsiloxane (Am =
NH2CH2CH2CH2Si(OEt)3) gels upon prolonged storage
in air through the transformation of the carbonyl cobaltate
anions into cobalt base carbonate and partial hydrolysis of
the Si(OEt)3 groups. The first step of this process involves
adsorption of O2 by the cobalt(II) hexamine anion, which
is then consumed for oxidation of the [Co(CO)4]– anꢀ
ions. The formation of a gel from complex 11 in a soluꢀ
tion in 2ꢀaminoethanol (0.03 mol L–1) proceeded slowly
and was completed in 30 days. After the removal of
the solvent in vacuo and washing of the solid phase
with ether, xerogel 12 was obtained as a lilacꢀcolored
powder. The elemental analysis data agree with the
{Co4C6[C2H4SiMe(OH)(OC2H4NH2)]6(HOC2H4NH2)18}•
•(OH)8•2CoCO3 formula. The IR spectrum of the xerogel
(see Fig. 6, spectrum 2) has no absorption band at
1870 cm–1 belonging to the [Co(CO)4]– anion. The broad
structured band in the region of 3600—3000 cm–1 is inꢀ
2
25
20
15
ν•10–3/cm–1
Fig. 7. Electronic absorption spectra of solutions of compounds
10 (1) and 11 (2) in MeCN.
heating of compound 11 to 250 °C led to complete deꢀ
composition of the [Co(CO)4]– fragments. In the IR specꢀ
trum of the solid product, the corresponding absorption
band at 1870 cm–1 disappeared. In the gas phase, H2 and
CO were present in a ratio of 3 : 7. The intensities and
shapes of the stretching bands of the MeSi, CH2Si,
CH2OSi, and CH2N fragments are changed only slightly.
The stretching and bending absorption bands of the N—H
bond are changed substantially. The intensities of the
bands at 3330, 3180 cm–1 (ν(N—H)), and 1570 cm–1
(δ(N—H)) decrease, whereas absorption in the region of
1700—1600 cm–1 increases. Two bands at 1660 and
1620 cm–1 should be assigned to the amide group (amide
I and amide II, respectively),19 which is generated due to
the insertion of the CO molecule at the N—H bond.
Upon heating to 250 °C, the weight loss was 72%. This
indicates that not only the [Co(CO)4]– anions decomꢀ
posed but also some of amine ligands were removed from
the environment about the Co2+ cation. This fact was
confirmed by a decrease in the intensities of the IR abꢀ
sorption bands of the N—H bond and also by the formaꢀ
tion of liquid products upon thermal decomposition. A
decrease in the intensities can also be associated with
the reaction of the NH2 groups with cobalt(0) giving
rise to H2.
2–
dicative of the presence of the CO3 anions and the
alcoholic and silanol groups. Absorption in the region of
1700—1500 cm–1 is assigned to the carbonate anion and
the amino groups (δ(NH2)). The presence of hexaalkylated
silylꢀsubstituted benzene fragments in the xerogel is conꢀ
firmed by absorption bands at 2925, 2860 cm–1 (C—H),
1250, and 800 cm–1 (SiCH3, SiCH2). The multiplet with
the center at 1060 cm–1 is associated with vibrations of
the C—O, C—N, and Si—O bonds of the COH, CNH2,
SiOC, SiOH, and SiOSi fragments. The aboveꢀconsidꢀ
ered data provide evidence that xerogel 12 has a carbonꢀ
ate structure with the involvement of organic fragments of
partially hydrolyzed hexaalkylated silylbenzene and the
hexamine cobalt(II) cation, which impart the lilac color
to the xerogel.
To summarize, new polyfunctional hexaalkylated
organosilicon 2ꢀaminoethoxybenzenes readily form comꢀ
plexes with CoCl2. The reaction with Co2(CO)8 is typical
only of the derivative containing primary amino groups.
The low solubilities of the resulting complexes are indicaꢀ
tive of their polymeric structures. Thermal decomposition
of these compounds affords porous amorphous structures
including crystalline phases of cobalt metal and CoCl2.
Heating of compounds 8, 9, and 10 to 600 °C under a
slow stream of argon caused the complete destruction of
the organic moieties of the molecules and the formation
of amorphous black silicaꢀcarbon solid phases containing
crystalline cobalt compounds. The weight losses were 45,
42, and 30%, respectively. The starting complexes had
negligibly small specific surfaces (Ssp), which is confirmed
by the fact that the desorption peak of nitrogen was not
found when the specific surface was determined by the
BET method. The products of pyrolysis of compounds 8,

Polyfunctional siliconꢀcontaining amines
Russ.Chem.Bull., Int.Ed., Vol. 51, No. 12, December, 2002 2283
Hexakis[bis(N,Nꢀdimethylꢀ2ꢀaminoethoxy)methylsilylꢀ
ethyl]benzene (5). A solution of compound 1 (10 g, 10.82 mmol)
in THF (40 mL) was added dropwise with stirring to a solution
of N,Nꢀdimethylꢀ2ꢀaminoethanol (23.2 g, 200 mmol) in THF
(30 mL) for 30 min. The reaction was accompanied by a slight
warmꢀup. Then the reaction mixture was stirred at 60 °C for 2 h.
The precipitate of HOCH2CH2NMe2•HCl that formed was filꢀ
tered off and the filtrate was concentrated. The residue was
dissolved in hexane and stirred with AGꢀ3 activated carbon for
5 h. Then the reaction mixture was filtered, the solvent was
distilled off, and the residue was heated in vacuo to obtain comꢀ
pound 5 as a viscous orange liquid in a yield of 6.26 g (36%).
Found (%): C, 55.75; H, 11.62; Si, 10.78. C72H162N12O12Si6.
Calculated (%): C, 55.55; H, 10.49; Si, 10.83. 1H NMR, δ: 0.24
(s, 18 H, MeSi); 0.87 (br.m, 12 H, CH2Si); 2.26 (s, 72 H,
MeN); 2.49 (t, 24 H, CH2N, J = 6.2 Hz); 2.6 (br.m, 12 H,
CArCH2); 3.80 (t, 24 H, CH2SiO, J = 6.2 Hz).
Experimental
Compounds 1—3 were synthesized with the use of 2ꢀaminoꢀ
ethanol and N,Nꢀdimethylꢀ2ꢀaminoethanol (Kaprolaktam Jointꢀ
Stock Company, Dzerzhinsk, Russia), methylvinyldichlorosilane
(Redkinsky pilot plant, Tver' Region, Russia), and dimethylꢀ
dichlorosilane (Kremniipolimer, Zaporozh´e, Ukraine). The
complexes of compounds 4—6 were prepared with the use of
cobalt chloride (Neokhim, St. Petersburg), dicobalt octaꢀ
carbonyl, and chromium hexacarbonyl (State ScientificꢀReꢀ
search Institute of Chemistry and Technology of Organoelement
Compounds, Moscow).
Commercial 2ꢀaminoethanol and N,Nꢀdimethylꢀ2ꢀaminoꢀ
ethanol were purified by distillation under reduced pressure.
According to the HPLC data (Milikhromꢀ1A, 2×64ꢀmm column;
SeparonꢀSGX, 5 µm; UV detector, 250 nm; hexane), dicobalt
octacarbonyl contained 98% of the major compound, and this
reagent was used without additional purification. Tetrahydrofuꢀ
ran, acetonitrile, dimethylformamide, and nꢀhexane were
purified according to known procedures.21 Hexakis(methylꢀ
dichlorosilylethyl)benzene (1), hexakis(methyldimethoxysilylꢀ
ethyl)benzene (2), hexakis(trimethylsilylethyl)benzene (3),11 and
triammine(tricarbonyl)chromium22 were synthesized according
to procedures described previously.
The IR spectra were recorded on a Specord IRꢀ75 spectroꢀ
photometer in liquid films between KBr plates, Nujol mulls, or
mineral oil (fluorohydrocarbon). The UVꢀVis spectra of soluꢀ
tions were measured on a Specord Mꢀ40 spectophotometer in
5ꢀmm quartz cells. The 1H NMR spectra were recorded on a
Bruker Avance DPXꢀ200 instrument (200 MHz) in solutions in
CDCl3 at 25 °C with Me4Si as the internal standard. Powder
Xꢀray diffraction study was carried out on a DRONꢀ3M
diffractometer (CuꢀKα radiation, graphite monochromator, difꢀ
fracted beam). The specific surfaces were determined by nitroꢀ
gen thermal desorption on a GKhꢀ1 chromatograph. The gases
were analyzed on a Tsvetꢀ530 gas chromatograph equipped with
a vacuum pump, a mercury pressure gauge, and a threeꢀway
cock (0.3×100ꢀcm stainless steel column, NaX molecular sieves,
thermal conductivity detector). This apparatus allowed us to
measure the pressure in a tube and introduce a gas sample exꢀ
cluding exposure to atmospheric oxygen. The simultaneous deꢀ
termination of H2, N2, O2, and CO was performed with the use
of argon as the carrier gas. The composition of the gas phase was
calculated taking into account the tabular values of therꢀ
mal conductivities of the gases.23 Liquid amino alcohols and
bis(N,Nꢀdimethylꢀ2ꢀaminoethoxy)dimethylsilane 6 were anaꢀ
lyzed on a 0.3×200ꢀcm stainless steel column with 5% SEꢀ30 on
solid Chromaton NꢀAWꢀDMCS.
Hexakis[bis(2ꢀaminoethoxy)methylsilylethyl]benzene (4).
2ꢀAminoethanol (11.91 g, 195 mmol) was added to compound 2
(9.43 g, 10.8 mmol) and the reaction mixture was refluxed at
120 °C for 2 h. Then methanol and excess amino alcohol were
distilled off. The residue was washed with hexane and heated in
vacuo at 70—80 °C for 5 h. Compound 4 was obtained as a
viscous orange liquid in a yield of 9.5 g (72%). Found (%):
C, 47.00; H, 10.00; Si, 13.09. C48H114N12O12Si6. Calculated (%):
C, 47.26; H, 9.42; Si, 13.81. 1H NMR, δ: 0.16 (s, 18 H, MeSi);
0.79 (br.m, 12 H, CH2Si); 2.19 (s, 12 H, NH2); 2.51 (br.m,
12 H, CArCH2); 2.73 (br.m, 24 H, CH2N); 3.64 (br.m, 24 H,
CH2SiO).
Bis(N,Nꢀdimethylꢀ2ꢀaminoethoxy)dimethylsilane (6). A soꢀ
lution of dimethyldichlorosilane (19.05 g, 150 mmol) in THF
(20 mL) was added dropwise with stirring to a solution of N,Nꢀdiꢀ
methylꢀ2ꢀaminoethanol (27.6 g, 310 mmol) and Et3N (30.4 g,
290 mmol) in THF (30 mL) for 30 min. The reaction was acꢀ
companied by a substantial warmꢀup. The reaction mixture was
stirred at ∼20 °C for 1 h and then heptane (40 mL) was added.
The mixture was filtered and the precipitate was washed with
hexane. The solvent was removed from the filtrate and the resiꢀ
due was distilled in vacuo. Compound 6 was obtained as a colorꢀ
less transparent liquid in a yield of 23.5 g (68%), b.p. 76 °C
(1 Torr), nD 1.4261 (cf. lit. data24: nD 1.4240). H NMR, δ:
0.15 (s, 6 H, MeSi); 2.27 (s, 12 H, MeN); 2.47 (t, 4 H, CH2N,
J = 6.4 Hz); 3.78 (t, 4 H, CH2O, J = 6.4 Hz).
20
20
1
Dichloro[bis(N,Nꢀdimethylꢀ2ꢀaminoethoxy)dimethylꢀ
silane]cobalt(II) (7). Compound 6 (8.33 g, 35.5 mmol) was added
to anhydrous CoCl2 (1.5 g, 11.6 mmol). The reaction was acꢀ
companied by a warmꢀup. The reaction mixture was stirred at
25 °C for 1 h and then at 100 °C for 1 h, washed with hexane,
and heated in vacuo at 70 °C for 2 h. Compound 7 was obtained
in a yield of 3.7 g (88%) as a viscous brightꢀblue liquid poorly
soluble in THF. Found (%): C, 32.12; H, 7.62; Cl, 18.93; Si, 7.41.
C10H26Cl2CoN2O2Si. Calculated (%): C, 32.97; H, 7.19;
Cl, 19.47; Si, 7.71. EAS (THF), λmax/nm (ε): 553 (22), 602 (78),
629 (91), 654 (91).
Dodecachloro{hexakis[bis(2ꢀaminoethoxy)methylsilylꢀ
ethyl]benzene}hexacobalt(II) (8). A solution of compound 4
(2.76 g, 2.26 mmol) in MeCN (100 mL) was added to CoCl2
(1.76 g, 13.6 mmol). The reaction mixture was stirred at 20 °C
for 1 h and then at 80 °C for 1 h. The reaction product precipiꢀ
tated upon cooling. The solvent was decanted from the precipiꢀ
tate and the latter was washed with MeCN. After the reꢀ
moval of the solvent in vacuo, complex 8 was obtained in a
yield of 4.0 g (89%) as a brightꢀblue solid, which is inꢀ
soluble in THF and MeCN and poorly soluble in DMF.
Found (%): C, 29.45; H, 6.07; Cl, 20.23; Co, 17.35; Si, 7.93.
C48H114Cl12Co6N12O12Si6. Calculated (%): C, 28.84; H, 5.75;
Cl, 21.28; Co, 17.69; Si, 8.43. EAS (DMF), λmax/nm (ε): 532
(200), 595 (438), 625 (563), 654 (463).
Dodecachloro{hexakis[bis(N,Nꢀdimethylꢀ2ꢀaminoꢀ
ethoxy)methylsilylethyl]benzene}hexacobalt(II) (9). A solution of
compound 5 (5.76 g, 3.7 mmol) in MeCN (15 mL) was added to
CoCl2 (2.8 g, 21.6 mmol). The reaction was accompanied by a

2284
Russ.Chem.Bull., Int.Ed., Vol. 51, No. 12, December, 2002
Ladilina et al.
slight warmꢀup. Then the reaction mixture was stirred at ∼20 °C
for 2 h, the solvent was distilled off in vacuo, and the residue was
washed with hexane. Brightꢀblue solid product 9 was obtained
in a yield of 7.5 g (88%). Found (%): C, 37.33; H, 6.55; Cl, 16.30;
Co, 14.67; Si, 6.89. C72H162Cl12Co6N12O12Si6. Calculated (%):
C, 37.03; H, 6.99; Cl, 18.21; Co, 15.14; Si, 7.21. EAS (MeCN),
This study was financially supported by the Russian
Foundation for Basic Research (Project Nos. 02ꢀ03ꢀ
32165, 00ꢀ15ꢀ97439, and 00ꢀ02ꢀ81206 Bel. 2000), INTAS
(Grant 97ꢀ1785), and the Russian Academy of Sciences
(complex programs "Nanomaterials and Supramolecular
Systems," Project "Structures and Construction of Nanoꢀ
materials," and "Fundamental Studies of Chemical Bonds
and Structures of Organometallic and Coordination Comꢀ
pounds"). The analyses were carried out in the Joint Use
Analytical Center (G. A. Razuvaev Institute of Organoꢀ
metallic Chemistry, Russian Academy of Sciences) and
were financially supported by the Russian Foundation for
Basic Research (Project No. 96ꢀ03ꢀ40ꢀ042).
λ
max/nm: 602, 633, 658, 694.
Tris[bis(N,Nꢀdimethylꢀ2ꢀaminoethoxy)dimethylsilane]coꢀ
balt(II) bis(tetracarbonylcobaltate) (10). Dicobalt octacarbonyl
Co2(CO)8 (1.21 g, 3.54 mmol) was added to a solution of
compound 6 (1.67 g, 7.12 mmol) in ether (10 mL) in a
Chugaev—Zerewitinoff apparatus equipped with a gas burette.
After 15 h, CO was liberated in a yield of 76% of the calculated
value. The reaction mixture was filtered off, the solvent was
distilled off in vacuo, and the residue was washed with hexane.
Compound 10 was obtained in a yield of 0.68 g (17%) as
a crimsonꢀcolored powder. Found (%): C, 42.69; H, 7.07;
Co, 16.42; Si, 8.06. C41H78Co3N6O14Si3. Calculated (%):
C, 43.19; H, 6.90; Co, 15.51; Si, 7.39. EAS (MeCN), λmax/nm:
532, 602.
Hexakis[bis(2ꢀaminoethoxy)methylsilylethyl]benzenediꢀ
cobalt(II) tetrakis(tetracarbonylcobaltate) (11). Dicobalt octaꢀ
carbonyl Co2(CO)8 (2.94 g, 8.61 mmol) was added to a solution
of compound 4 (3.5 g, 2.87 mmol) in ether (10 mL). After 15 h,
CO was liberated in a yield of 95% of the calculated value. The
reaction mixture was washed with ether and reprecipitated with
ether from a solution in MeCN. Compound 11 was obtained in
a yield of 2.1 g (36%) as a crimsonꢀred powder. Found (%):
C, 38.46; H, 5.72; Co, 17.79; Si, 8.48. C64H114Co6N12O28Si6.
Calculated (%): C, 38.02; H, 5.68; Co, 17.49; Si, 8.33. EAS
(MeCN), λmax/nm (ε): 400 (392), 532 (545).
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added to a weighed sample of the corresponding compound
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2650 (H3N+); 1870 (C=O); 1620 (H2O); 1250, 800 (Si—CH2,
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Received June 20, 2001;
in revised form April 3, 2002