Selective Si-O-Si bond cleavage as synthetic access to functionalized, hydrolysis-stable zinc silanolates

Article abstract of DOI:10.1515/znb-2009-11-1240

The selective cleavage of the strong and poorly reactive Si-O-Si bond in functionalized siloxanes under mild conditions is a decisive task for modern synthetic chemistry. Simple treatment of the aminomethyl-functionalized disiloxanes 1, 6, (R, R)-7 and 8

Full text of DOI:10.1515/znb-2009-11-1240

Selective Si–O–Si Bond Cleavage as Synthetic Access to Functionalized,
Hydrolysis-stable Zinc Silanolates
Christian Da¨schlein and Carsten Strohmann
Anorganische Chemie, Technische Universita¨t Dortmund, Otto-Hahn-Straße 6, 44227 Dortmund,
Germany
Reprint requests to Prof. Dr. Carsten Strohmann and Dr. Christian Da¨schlein.
Fax: (+) 49-231-755-7062. E-mail: mail@carsten-strohmann.de
Z. Naturforsch. 2009, 64b, 1558 – 1566; received September 11, 2009
Dedicated to Professor Hubert Schmidbaur on the occasion of his 75th birthday
The selective cleavage of the strong and poorly reactive Si–O–Si bond in functionalized silox-
anes under mild conditions is a decisive task for modern synthetic chemistry. Simple treatment of
the aminomethyl-functionalized disiloxanes 1, 6, (R,R)-7 and 8 ([R2(CH2NRꢀ)SiO]2, R = Me or Ph,
NRꢀ = NC5H10, NC5H8(CH3)2 or NC4H7(CH3)) with zinc(II) bromide and zinc(II) chloride, respec-
tively, results in the formation of highly hydrolysis-stable, molecular zinc silanolates which were long
time supposed to be unstable in the presence of water. Both, the selective cleavage of the Si–O–Si
bond as well as the formation of the molecular zinc silanolates are independent of the substituents
at silicon, the used zinc(II) salt or the aminomethyl side arm. Detailed structural studies showed that
zwitterionic interactions are the reason for the high stability towards hydrolysis of the formed zinc
silanolates 9, 10, (R,R)-11 and 12. NMR studies are indicative of the same structure of these molec-
ular systems in solution as in the solid state.
Key words: Metallasilanolates, Zwitterionic Compounds, Zinc, Disiloxanes, Metal Complexes
Introduction
achievable by simple treatment of 1 with zinc(II) bro-
mide and zinc(II) acetate in the presence of water
which resulted in the formation of the first hydrolysis-
stable and unexpected, molecular metallasilanolates of
transition metals (Scheme 1) [5 – 7].
As part of our studies on aminomethyl-functional-
ized organosilanes [4, 8, 9] we systematically investi-
gated the generality of this reaction. Besides the pre-
viously reported variation of the metal salt – ZnBr2
and Zn(AcO)2 – we also wanted to investigate whether
the selective cleavage of the Si–O–Si linkage is also
possible in substrates with different substituents at sili-
con and varying, metal-directing amino side arms [10].
Based thereon, we herein present the crystal structures
of four newly synthesized zinc silanolates prepared via
selective cleavage of the Si–O–Si unit in functionalized
Many industrial applications of functionalized
siloxanes are based on their high chemical and phys-
ical resistance, e. g. their high stability towards heat
and radiation or their chemical inertness [1, 2]. Nev-
ertheless, there is an increasing demand for simple
methods for the transformation of the strong and
unreactive Si–O–Si linkage in functionalized silox-
anes due to the growing importance of discussions
concerning sustainability and recycling. Despite the
great importance, only few concrete approaches to
the cleavage of condensed siloxanes have been re-
ported of so far [3]. Most recently, we presented the
mild and selective cleavage of the Si–O–Si unit in
1,3-bis(piperidinomethyl)tetramethyldisiloxane(1)[4],
Scheme 1. Synthesis of
the first hydrolysis-stable,
molecular zinc silanolates of
transition metals [4].
c
0932–0776 / 09 / 1100–1558 $ 06.00 ꢀ 2009 Verlag der Zeitschrift fu¨r Naturforschung, Tu¨bingen · http://znaturforsch.com
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C. Da¨schlein – C. Strohmann · Selective Si–O–Si Bond Cleavage
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Scheme 2. Synthesis of the func-
tionalized disiloxanes 1, 6 (upper
row), (R,R)-7 and 8 (lower row).
Scheme 3. Synthesis of
the zinc silanolates 9
and 10.
disiloxanes with zinc(II) salts in the presence of water, bination of the corresponding solutions of the disilox-
which extend the cleavage of Si–O–Si units to further anes and the zinc(II) salts resulted in a rapid clouding
functionalized systems.
of the solution. Thereby, the reaction of 1 with ZnCl2
and the reaction of 6 with ZnBr2 yielded crystalline
solids of the zinc silanolates 9 and 10, formed via se-
lective cleavage of the Si–O–Si unit (Scheme 3). The
formed zinc silanolates have finally been purified via
washing with ice-cold acetonitrile. It has to be empha-
sized that both zinc silanolates are stable for at least
one year at r. t. and without inert gas atmosphere.
In case of the reaction of the disiloxane (R,R)-
7 with ZnBr2, a crystalline solid could be isolated
after crystallization from acetonitrile/acetone and re-
crystallization from iso-propanol. As the isolated zinc
silanolate (R,R)-11 features a much better solubility
in commonly used organic solvents, it was purified
by washing with ice-cold Et2O instead of acetonitrile.
All crystallization and re-crystallization attempts of
12 from acetone or acetonitrile have been unsuccess-
ful due to the rapid formation of the solid and its in-
sufficient solubility in common solvents. Finally, the
combination of 8, dissolved in non-dried thf, and two
equivalents of ZnBr2 dissolved in the same solvent at
−78 ◦C and storage for three weeks at this temperature
resulted in the isolation of a crystalline solid of the zinc
silanolate 12 (Scheme 4).
Results and Discussion
Synthesis
For the systematic study of the generality of the
lately developed metal-induced Si–O–Si cleavage un-
der formation of water-stable metallasilanolates, we
synthesized a series of differently substituted, func-
tionalized disiloxanes. Disiloxane 1 has been synthe-
sized by the previously reported method via amina-
tion of 1,3-bis(chloromethyl)tetramethyldisiloxane (4)
[4] with a four-fold excess of piperidine. In addi-
tion, we also synthesized the diphenylsubstituted dis-
iloxane 6 by the same method. The two newly syn-
thesized disiloxanes (R,R)-7 and 8 have been pre-
pared via an analogous method using a two-fold ex-
cess of (2R)-methylpyrrolidine ((R,R)-7) and cis-2,6-
dimethylpiperidine (8), respectively, and 2.2 equiva-
lents of trietyhlamine for complexation of the formed
HCl (Scheme 2).
To investigate the reactivity of the synthesized dis-
iloxanes towards zinc(II) salts, all compounds were
dissolved in non-dried acetone and added to a solution
of two equivalents of ZnCl2 (in case of 1) and ZnBr2(in
case of 6, (R,R)-7 and 8), respectively, in the same sol- anes with zinc(II) salts resulted in the formation of
vent under normal atmosphere. In all cases, the com- highly hydrolysis-stable metallasilanolates via selec-
Hence, the treatment of all presented disilox-
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C. Da¨schlein – C. Strohmann · Selective Si–O–Si Bond Cleavage
Scheme 4. Synthesis
of the zinc silanolates
(R,R)-11 and 12.
tive cleavage of the Si–O–Si linkage in the correspond-
ing reactant. Thereby, it seems that the whole reaction
sequence is a kinetically controlled process, as a de-
crease of the reaction temperature strongly reduces its
speed, as shown for the formation of 12. Furthermore,
the successful isolation of the zinc silanolates 9 and
10 proves that their formation out of disiloxanes is not
only limited to the dimethyl-substituted reactant 1, but
can also be accomplished using the significantly more
bulky phenyl-substituted 6 as well as zinc(II) chloride
instead of zinc(II) bromide (and zinc(II) acetate, re-
spectively, see ref. [4]). Finally, the metallasilanolate
formation is also independent of the amino side arm, as
shown by the formation of (R,R)-11 and 12. As a matter
of fact, (R,R)-11 is the first water-stable zinc silanolate
with chirality in the amino side arm (12 is the meso-
compound). The following chapter deals with the crys-
tal structure analyses of the zinc silanolates described
above.
Crystal structure determinations
Compounds 9 and 10 crystallized from ace-
tone/water in the monoclinic space group P21/n
(9) and P21/c (10), respectively, as colorless nee-
dles. (R,R)-11 crystallized from acetonitrile/acetone/i-
propanol/water in the monoclinic space group P21 as
Fig. 1. Molecular structures of 9 (top) and 10 (bottom) in
the crystal; the numbering scheme of the hydrogen atoms
is omitted for clarity (except the hydrogens located at
˚
the nitrogen atoms); selected bond lengths (A), 9: Si–O
◦
1.618(2), Zn–O 1.977(2), Znꢀ–O 1 1.988(2); symmetry trans-
colorless needles, 12 from thf/water at −78 C in the
ꢀ
orthorhombic space group P42/n as colorless blocks
(see Figs. 1 and 2, Tables 1 and 2 for additional crys-
tallographic information and details of the structure re-
finement).
formations used for the generation of equivalent atoms, :
−x + 2, −y + 2, −z; 10: Br(1)–Zn(1) 2.316(1), Br(2)–Zn(1)
2.410(1), Si(1)–O(1) 1.607(4), Zn(1)–O(1) 1.987(4), Zn(1)ꢀ–
O(1) 2.026(4), Zn(1)–O(1)ꢀ 2.026(4), Zn(1)–Zn(1)ꢀ 2.895(2);
symmetry transformations used for the generation of equiva-
lent atoms, ꢀ: −x+1, −y+1, −z.
All four compounds exhibit a central Zn–O–Znꢀ–Oꢀ
four-membered ring, with each zinc atom in a sligthly
distorted tetrahydral environment with contacts to two
oxygen and two halide atoms (9: halide = Cl; 10, (R,R)-
11 and 12: halide = Br) [11]. Thereby, it has to be noted
that 9, 10 and 12 possess a crystallographic center of
inversion. The oxygen-zinc distances are significantly
longer than the sum of the covalent radii of oxygen and
are in the range of preponderantly ionic interactions
between oxygen and zinc, dominating in e. g. zinc sil-
˚
icates like Willemite (mean value 1.98 A) [12]. More-
over, all hydrogen atoms attached to nitrogen were
found and freely refined in the difference Fourier maps
in all four compounds, whereas at the oxygen atoms
of the Si–O units no hydrogens could not be located.
˚
zinc (1.89 A) [12] (see Table 1). Yet, these distances
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C. Da¨schlein – C. Strohmann · Selective Si–O–Si Bond Cleavage
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˚
Table 1. Selected bond lenghts (A) for 9, 10, (R,R)-11 and 12 with estimated standard deviations in parentheses.
9
10
(R,R)-11
1.982(4)
1.992(4)
1.623(4)
12
O–Zn (9, 10 and 12; O1–Zn1 for (R,R)-11)
O–Znꢀ (9, 10 and 12; O1–Zn2 for (R,R)-11)
Si–O (9, 10 and 12; Si1–O1 for (R,R)-11)
1.977(2)
1.988(2)
1.618(2)
1.987(4)
2.026(4)
1.607(4)
1.966(6)
2.004(6)
1.618(5)
Experimentally observed
Not observed, disfavored
silanolate-like
silanol-like
"
" structure
"
structure"
H
R2N
R2N
R'
Si
O
R'
R''
Si
O
Br2Zn
R''
X2Zn
H
A
B
Fig. 3. Experimentally observed silanolate-like structure A
(left) and not observed silanol-like structure B (right).
viously published systems 2 and 3 [4] – the existence
of molecular metallasilanolates in the presence of wa-
ter and the preference of the silanolate-like structure A
with the hydrogen atom located at the nitrogen atom
(Fig. 3, left) over the also possible, but not observed
silanol-like structure B with the hydrogen located at
the oxygen (Fig. 3, right).
NMR studies
Fig. 2. Molecular structures of (R,R)-11 (top) and 12 (bot-
tom) in the crystal; the numbering scheme of the hydrogen
atoms is omitted for clarity (except the hydrogens located
Recently we reported on detailed NMR-spectro-
scopic studies of the disiloxane 1 as well as on the two
zinc silanolates 2 and 3 [4]. These studies showed com-
parable NMR spectra of both zinc silanolates in solid
state and in solution, thus indicating the same molec-
ular structure in solution as in the solid. The question
concerning the structure in solution is of particular in-
terest with respect to the understanding of chemical
reactions of these systems or related compounds. Al-
though all newly synthesized compounds have been
characterized via NMR spectroscopy in solution, 10
was investigated additionally in the solid state to fur-
ther confirm its structure determined via X-ray diffrac-
tion as it is the first representative of this class of com-
pounds bearing bulky aromatic substituents at the sili-
con atoms (see Supplementary Information for relevant
NMR spectra; online only).
˚
at the nitrogen atoms); selected bond lengths (A), (R,R)-
11: Si(1)–O(1) 1.623(4), Zn(1)–O(1) 1.982(4), Zn(2)–O(1)
1.992(4), Si(2)–O(2) 1.625(5), Zn(1)–O(2) 1.979(4), Zn(2)–
O(2) 1.992(4); 12: Si–O 1.618(5), Zn–O 1.966(6), Znꢀ–O
2.004(6), Zn–Oꢀ 2.004(6); symmetry transformations used
ꢀ
for the generation of equivalent atoms, : −x + 2, −y + 1,
−z+2.
Thus, a positive charge is located at the amino func-
tion counterbalanced by a negative charge at the oxy-
gen. Based on this observation, the extraordinary high
stability of these molecular zinc silanolates in the pres-
ence of water can be explained by the charge separa-
tion through the formation of zwitterionic species, as
has been reported for compounds 2 and 3 [4]. It is
well known in many areas of chemistry and biology
that such zwitterionic species strongly stabilize molec-
ular structures, e. g. in many biological systems (like
amino acids) [4, 13, 14]. Analogously, the intramolecu-
According to the 29Si NMR spectra, only one de-
fined compound is present in solution. This is in per-
fect agreement with the NMR studies on 2 and 3 and
lar zwitterion effect in the zinc silanolates 9, 10, (R,R)- confirms the homogeneity of the whole material of 10
11 and 12 does not only explain their ready synthesis,
but also their stability against hydrolysis. Thus, these
four systems further confirm – in addition to our pre-
not only in the crystal, but also in solution. Thereby,
the 29Si chemical shift in solution is comparable to
the one in the solid state. The 13C NMR signals also
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C. Da¨schlein – C. Strohmann · Selective Si–O–Si Bond Cleavage
Table 2. Crystal structure data for 9, 10, (R,R)-11 and 12.
Compound
9
10
(R,R)-11
12
Formula
C16H38Si2N2O2Zn2Cl4 C36H46Si2N2O2Zn2Br4 C16H38Si2N2O2Zn2Br4 C20H46Si2N2O2Zn2Br4
Mr, g mol−1
619.20
1045.31
797.04
853.14
Crystal size, mm3
Crystal system
Space group (no.)
0.40×0.20×0.20
monoclinic
P21/n (14)
9.0390(8)
14.6022(13)
10.3123(9)
96.3314(17)
1352.8(2)
2
0.40×0.40×0.20
monoclinic
P21/c (14)
9.919(3)
14.318(3)
14.853(4)
96.935(4)
2094.0(9)
2
0.30×0.10×0.10
monoclinic
P21 (4)
9.4749(3)
14.8840(5)
10.2967(4)
96.779(3)
1441.93(9)
2
0.20×0.10×0.10
orthorhombic
P42/n (86)
18.6763(4)
18.6763(4)
10.1785(6)
90
3550.3(2)
4
1.60
˚
a, A
˚
b, A
˚
c, A
β, deg
3
˚
V, A
Z
Dcalcd, g cm−3
µ(MoKα ), mm−1
F(000), e
1.52
2.3
640
1.66
5.1
1040
1.84
7.3
784
5.9
1696
θ range, deg
2.43 – 25.00
−10 ≤ h ≤ 10
−17 ≤ k ≤ 17
−12 ≤ l ≤ 12
28001
2383
0.1092
1.98 – 25.00
−11 ≤ h ≤ 11
−17 ≤ k ≤ 16
−16 ≤ l ≤ 17
11794
1.99 – 26.00
−11 ≤ h ≤ 11
−18 ≤ k ≤ 18
−12 ≤ l ≤ 12
27242
5640
0.0638
2.18 – 26.00
−22 ≤ h ≤ 23
−18 ≤ k ≤ 23
−12 ≤ l ≤ 11
30564
3475
0.0527
hkl range
Refl. measured
Refl. unique
Rint
3684
0.0526
Structure refinement
Full-matrix least-squares on F2
Final indices R1/wR2 [I ≥ 2σ(I)] 0.0344 / 0.0669
0.0516 / 0.1239
0.0797 / 0.1305
–
1.052
3684 / 0 / 221
2.196 / −1.284
0.0385 / 0.0820
0.0522 / 0.08382
−0.011(12)
0.0428 / 0.1281
0.0734 / 0.1333
–
1.019
3475 / 0 / 154
1.580 / −0.438
R1/wR2 indices (all data)
x (Flack)
0.0512 / 0.0732
–
Goodness-of-fit on F2
Data/restraints/parameter
1.033
2383 / 0 / 133
0.323 / −0.288
1.010
5640 / 1 / 267
0.905 / −0.612
−3
˚
Largest diff. peak / hole, e A
have comparable values in the solid state and in solu- salt, the substituents at silicon and the metal-directing
tion. The resonance signals of the NCH2CC and the aminomethyl side arm. In this context, also the first
NCCCH2 groups are split in the solid-state spectrum molecular zinc silanolate with stereoinformation in the
indicating the hindered rotation of these groups (the aminomethyl side arm could be synthesized ((R,R)-
13C NMR signals of the aromatic substituents are split 11). X-Ray crystal structure analyses showed that
too). In the 1H NMR spectrum, a water signal is clearly the formation of zwitterionic species with a positive
present, thus underlining the high stability of 10 to- charge at the protonated nitrogen and a negative charge
wards hydrolysis. Furthermore, the resonance signals at the oxygen atom are the reason for the high sta-
for the NCH2CC protons are split in solution, indi- bility of these systems in the presence of water. A
cating the coordination of zinc(II) bromide (addition possible silanol-like structure without charge separa-
of ZnBr2 had no effect on the spectra). Overall, the tion and the hydrogen atom located at the oxygen
performed NMR studies of 10 are consistent with the could not be detected in any case. NMR studies on
NMR studies on 2 and 3 and confirm the same struc- the zinc silanolate 10 in the solid state and in solu-
ture of molecular zinc silanolates in solution and in the tion are indicative for the same structure in solution
solid state as determined by X-ray diffraction analysis. and in the solid state. At the moment we are try-
ing to apply this new reaction to a broader field of
aminoalkyl-functionalized siloxanes with other diva-
lent metal salts.
Conclusion
A series of hydrolysis-stable, molecular zinc
silanolates has been synthesized via selective cleav-
age of the strong and poorly reactive Si–O–Si link-
age in functionalized disiloxanes with simple zinc(II)
halides. Bond cleavage as well as metallasilanolate for-
Experimental Section
General remarks
1,3-Bis(chloromethyl)tetramethyldisiloxane was synthe-
mation proved to be independent of the used zinc(II) sized by hydrolysis of (chloromethyl)dimethylchlorosilane.
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C. Da¨schlein – C. Strohmann · Selective Si–O–Si Bond Cleavage
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(Chloromethyl)dimethylchlorosilane was purchased by CD3CN): δ = 0.06 (s 12H, SiCH3), 1.00 (d, 3JHH = 5.94 Hz,
ABCR GmbH & Co. KG. Toluene, used for the synthesis 6H, NCH(CH32)CC), 1.20 – 1.35 (m, 2H, CH2), 1.43, 2.32
of the disiloxanes 1, 6, (R,R)-7 and 8, was dried according (AB systems, JAB = 14.3 Hz, 4H, SiCH2N), 1.55 – 1.70
to standard procedures. All other solvents – including (m, 4H, CH2), 1.75 – 1.90 (m, 2H, CH2), 1.90 – 2.00 (m,
the NMR solvents – were used without special drying 2H, CH2), 2.15 – 2.25 (m, 2H, CH2), 3.05 – 3.15 (m, 2H,
1
procedures.
NCH(CH3)CC). – { H}13C NMR (75.5 MHz, CD3CN):
δ = 0.47, 0.66 (2C each, SiCH3), 19.3 (2C, NCH(CH3)CC),
22.5 (2C, NCH2CH2C), 33.1 (2C, NCHCH2C), 45.9 (2C,
SiCH2N), 57.7 (2C, NCH2CC), 64.7 (2C, NCHCC). –
The NMR spectra in solution were measured on Bruker
DRX-300, Bruker Avance-400 and a Bruker Avance-500
NMR spectrometers with an external standard of tetram-
ethylsilane (TMS, δ = 0.0). Signal assignments were sup-
ported by DEPT-135- and C,H-COSY experiments and the
relative intensities of the resonance signals. The solid-state
{ H}29Si NMR (59.6 MHz, CD3CN): δ = 4.84 (2Si,
1
SiCH2N).
NMR spectrum was measured on a Bruker DSX-400 NMR 1,3-Bis[cis-2,6-dimethyl(piperidinomethyl)]tetramethyl-
spectrometer. Abbreviations: s = singlet, d = duplet, t = disiloxane (8)
triplet, m = multiplet, br = broad signal. All measurements
Compound 8 was synthesized as described for (R,R)-
7. 4.81 g (47.6 mmol, 2.2 eq.) of triethylamine and
4.89 g (43.3 mmol, 2 eq.) of cis-2,6-dimethylpiperidin
were added to 5.00 g (21.6 mmol) of 1,3-bis(chlormeth-
yl)tetramethyldisiloxane (1), dissolved in 30 mL toluene,
and the mixture was refluxed for 28 h. Afterwards, all
volatile compounds were removed under reduced pressure,
the residue dissolved in a minimum amount of n-pentane
and filtered. Finally, the crude product was cleaned via
bulb-to-bulb distillation (oven-temperature: 200 ◦C; pres-
sure: ∼ 3·10−3 mbar). Yield: 6.32 g (16.4 mmol, 76 %). –
1H NMR (300.1 MHz, CDCl3): δ = 0.15 (s, 12H, SiCH3),
have been accomplished at 25 ◦C.
1,3-Bis(piperidinomethyl)tetramethyldisiloxane (1)
The disiloxane 1 was synthesized via the recently
published method starting from 1,3-bis(chloromethyl)tetra-
methyldisiloxane (4). All experimental details can be found
in ref. [4].
1,3-Bis(piperidinomethyl)tetraphenyldisiloxane (6)
Compound 6 was synthesized as described for 1 start-
3
ing from 1,3-bis(chloromethyl)tetraphenyldisiloxane. Yield:
1.08 (d, JHH = 6.22 Hz, 12 H, NCH(CH3)CC), 1.15 – 1.30
1
816 mg (1.41 mol, 68 %). – H NMR (300.1 MHz, C6D6):
(m, 6H, NCHCH2CH2), 1.45 – 1.65 (m, 6H, NCHCH2CH2),
2.27 (s, 4H, SiCH2N), 2.35 – 2.45 (m, 4H, NCHCC). –
δ = 1.28 – 1.39 (m, 4H, NCCCH2), 1.43 – 1.61 (m, 8H,
NCCH2C), 2.27 – 2.49 (m, 8H, NCH2CC), 2.68 (s, 4H,
SiCH2N), 7.18 – 7.37 (m, 12H, aromat. H), 7.70 – 8.03 (m,
1
{ H}13C NMR (75.5 MHz, CDCl3): δ = 3.04 (4C, SiCH3),
22.1 (4C, NCH(CH3)CC), 24.4 (2C, NCCCH2), 35.1 (4C,
NCCH2C), 41.5 (2C, SiCH2N), 58.2 (4C, NCHCC). –
1
8H, aromat. H). – { H}13C NMR (75.5 MHz, C6D6):
1
{ H}29Si NMR (59.6 MHz, CDCl3): δ = 5.86 (2Si,
δ = 24.2 (2C, NCCCH2), 26.6 (4C, NCCH2C), 50.6 (2C,
SiCH2N), 59.0 (4C, NCH2CC), 128.0 (8C, C-m, C6H5),
129.9 (4C, C-p, C6H5), 135.0 (8C, C-o, C6H5), 137.4 (4C,
SiCH2N). – C20H44N2OSi2 (384.8): calcd. C 62.4, H 11.5,
N 7.28; found C 62.3, H 11.3, N 7.36.
1
C-i, C6H5). – { H}29Si NMR (59.6 MHz, C6D6): δ = −17.2
(2Si, SiCH2N). – C36H44N2OSi2 (576.9): calcd. C 75.0,
Synthesis of the zinc silanolate 9
H 7.69, N 4.86; found C 75.9, H 8.0, N 4.5.
The reaction was carried out in non-dried solvents and
under normal atmosphere. 575 mg (1.75 mmol, 0.5 eq.)
of 1,3-bis(piperidinomethyl)tetramethyldisiloxane (1) were
added at r. t. to 477 mg (3.50 mmol) of zink(II) chlo-
1,3-Bis[(2R)-methyl(pyrrolidinomethyl)]tetramethyl-
disiloxane ((R,R)-7)
(R,R)-7 was synthesized as described for 1. 1.19 g ride, dissolved in 5 mL of acetone, and stored for 24 h
(11.7 mmol, 2.2 eq.) of triethylamine and 0.91 g (10.6 mmol, for slow crystallization. Afterwards, the remaining solvent
2 eq.) of (2R)-methylpyrrolidine were added to 1.23 g was removed, and the crystalline solid was washed with a
(5.34 mmol) of 1,3-bis(chlormethyl)tetramethyldisiloxane minimum amount of ice-cold acetonitrile. Yield: 484 mg
(1), dissolved in 10 mL toluene, and the mixture was re- (0.78 mmol, 87 %). – 1H NMR (500.1 MHz, [D6]DMSO):
fluxed for 34 h. Afterwards, all volatile compounds were δ = 0.14 (s, 12H, SiCH3), 1.30 – 1.40 (m,4H, NCCCH2),
removed under reduced pressure, the residue was dissolved 1.50 – 1.60, 1.60 – 1.70 (m, 4H each, NCCH2C), 1.90 – 2.10
in a minimum amount of n-pentane and filtered. Finally, (br, 4H, SiCH2N), 2.10 – 2.20, 2.80 – 3.00 (br, 4H each,
1
the crude product was cleaned via bulb-to-bulb distilla- NCH2CC). – { H}13C NMR (125.8 MHz, [D6]DMSO): δ =
◦
tion (oven-temperature: 165 C; pressure: ∼ 3·10−3 mbar). 0.7 (4C, SiCH3), 23.7 (2C, NCCCH2), 25.0 (4C, NCCH2C),
Yield: 0.54 g (1.76 mmol, 31 %). – 1H NMR (300.1 MHz, 50.7 (2C, SiCH2N), 57.3, 58.3 (2C each, NCH2CC). –
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1564
C. Da¨schlein – C. Strohmann · Selective Si–O–Si Bond Cleavage
1
{ H}29Si NMR (99.4 MHz, [D6]DMSO): δ = 4.87 (2Si, SiCH2N). – C36H46N2O2Si2Zn2Br4 (797.0): calcd. C 24.1,
SiCH2N). – C16H38N2O2Si2Zn2Cl4 (619.2): calcd. C 31.0, H 4.81, N 3.51; found C 24.5, H 4.87, N 3.62.
H 6.19, N 4.52; found C 31.3, H 6.3, N 4.5.
Synthesis of the zinc silanolate 12
Synthesis of the zinc silanolate 10
40 mg (0.10 mmol) of 1,3-bis[cis-2,6-dimethyl(piperid-
The reaction was carried out in non-dried solvents and
◦
inomethyl)]tetramethyldisiloxane (8) were added at −78 C
under normal atmosphere. The reaction of 6 and ZnBr2
to 46.8 mg (0.21 mmol, 2 eq.) of ZnBr2, dissolved in 15 mL
was accomplished by the same procedure as described
of thf, and stored for three weeks for slow crystallization
above for the reaction of 1 with ZnCl2. Yield: 327 mg
at this temperature. Afterwards, the solvent was removed
◦
1
(0.31 mmol, 86 %). M. p. 242 C. – H NMR (400.1 MHz,
[D6]DMSO): δ = 1.15 – 1.25 (m,4H, NCCCH2), 1.25 – 1.55
(m, 8H, NCCH2C), 2.15 – 2.25 (br, 4H, NCH2CC), 2.30 –
2.45 (br, 4H, SiCH2N), 2.50 – 2.70 (br, 4H, NCH2CC), 7.30 –
7.40 (m, 12H, H-m, H-p), 7.55 – 7.65 (m, 8H, H-o). –
at −78 ◦C, and the crystalline solid was washed with a
minimum amount of ice-cold acetonitrile. Yield: 60.5 mg
(0.07 mmol, 76 %). – 1H NMR (400.1 MHz, [D6]DMSO):
δ = 0.14, 0.19 (br, 6H each, SiCH3), 0.75 – 1.10 (br, 6H,
NCHCH2CH2), 1.25 (br, 12 H, NCH(CH3)CC), 1.40 – 1.65
(br, 6H, NCHCH2CH2), 2.08 (s, 4H, SiCH2N), 2.50 – 2.60,
{ H}13C NMR (100.1 MHz, [D6]DMSO): δ = 22.7 (2C,
1
NCCCH2), 25.2 (4C, NCCH2C), 49.3 (2C, SiCH2N), 57.5
(4C, NCH2CC), 127.6 (8C, C-m, C6H5), 129.8 (4C, C-p,
C6H5), 133.9 (8C, C-o, C6H5), 136.4 (4C, C-i, C6H5). –
1
3.10 – 3.20 (br, 1H each, NCH(CH3)CC). – { H}13C NMR
(100.6 MHz, [D6]DMSO): δ = 1.70 (4C, SiCH3), 18.9,
22.1 (2C each, NCH(CH3)CC), 22.0 (2C, NCHCH2CH2),
34.3 (4C, NCHCH2C), 43.2 (2C, SiCH2N), 59.9, 60.3 (2C
{ H}29Si NMR (59.6 MHz, [D6]DMSO): δ = −17.8
1
(2Si, SiCH2N). – DSX 400 solid-state NMR: 13C NMR
(VACP/MAS, νrot = 7000 Hz): δ = 22.5 (2C, NCCCH2),
23.1, 24.8 (2C each, NCCH2C), 50.5 (2C, SiCH2N), 56.1,
58.3 (2C each, NCH2CC), 128.6, 129.5, 131.3, 135.1,
135.8, 137.4, 139.1 (12 C, all aromatic C). – 29Si NMR
(VACP/MAS, νrot = 7000 Hz): δ = −21.6 (1Si, SiCH2N). –
15N NMR (VACP/MAS, νrot = 6500 Hz): δ = −323.1 (1N,
SiCH2N). – C36H46N2O2Si2Zn2Br4 (1045.3): calcd. C 41.4,
H 4.44, N 2.68; found C 40.8, H 4.39, N 2.66.
1
each, NCHCC). – { H}29Si NMR (59.6 MHz, [D6]DMSO):
δ = 5.21 (2Si, SiCH2N). – C36H46N2O2Si2Zn2Br4 (853.1):
calcd. C 28.2, H 5.43, N 3.28; found C 28.4, H 5.57, N 3.32.
Crystal structure determinations
Crystal structure determinations of 9 and 10 were accom-
plished on a Bruker APEX diffractometer (D8 three-circle
goniometer, Bruker AXS); data collection, cell determina-
tion and refinement: SMART (version 5.622, Bruker AXS,
2001); integration: SAINT PLUS (version 6.02, Bruker
Synthesis of the zinc silanolate (R,R)-11
The reaction was carried out in non-dried solvents and AXS, 1999); empirical absorption correction: SADABS (ver-
under normal atmosphere. 40 mg (0.12 mmol) of 1,3- sion 2.01, Bruker AXS, 1999). Crystal structure determina-
bis[(2R)-methyl(pyrrolidinomethyl]tetramethyldisiloxane
tions of (R,R)-11 and 12 were accomplished on an Oxford-
((R,R)-7), dissolved in a mixture of 10 mL of acetonitrile CCD diffractometer; data collection: CRYSALIS (Oxford,
and 5 mL of iso-propanol, were added at r. t. to 54.8 mg 2008); cell determination and refinement: CRYSALIS RED
(0.24 mmol, 2 eq.) of ZnBr2, dissolved in 3 mL of ace- (Oxford 2008); empirical absorption correction. The struc-
tone, and stored for 2 d for slow crystallization. After tures were solved by applying direct and Fourier methods,
re-crystallization of the crude product from iso-propanol, using SHELXS-90 [15] and SHELXL-97 [16]. The crys-
the remaining solvent was removed and the crystalline solid tals were mounted at r. t., the crystal structure determina-
◦
washed with a minimum amount of ice-cold iso-propanol. tions were carried out at −100 C (MoKα radiation, λ =
Yield: 64.0 mg (0.08 mmol, 66 %). – 1H NMR (300.1 MHz, 0.71073 A). The non-H atoms were refined anisotropically.
˚
3
[D6]DMSO): δ = 0.14 (s 12H, SiCH3), 1.07 (d, JHH
=
All H atoms – except the ones located at the nitrogen atoms
3
6.2 Hz, 3H, NCH(CH3)CC), 1.21 (d, JHH = 6.2 Hz, 3H, – were placed in geometrically calculated positions and as-
NCH(CH3)CC), 1.25 – 1.55 (m, 4H, CH2), 1.65 – 1.75 signed a fixed isotropic displacement parameter based on a
(m, 2H, CH2), 1.75 – 1.90 (m, 4H, CH2), 2.00 – 2.15 (m, riding model. The hydrogen atoms located in the difference
2H, CH2), 2.25 – 2.40, 2.85 – 3.00 (m, 2H each, SiCH2N), Fourier map at the nitrogen atoms of the aminomethyl groups
3.10 – 3.20 (m, 2H, NCH(CH3)CC). – { H}13C NMR were found and could be freely refined.
1
(75.5 MHz, [D6]DMSO): δ = 0.61 (4C, SiCH3), 20.9 (2C,
CCDC 743382 (9), CCDC 743383 (10), CCDC 743384
NCH(CH3)CC), 21.3 (2C, NCH2CH2C), 30.7, 31.5 (1C ((R,R)-11) and CCDC 743385 (12) contain the supplemen-
each, NCH2CH2CH2), 44.2, 44.4 (1C each, SiCH2N), 55.7, tary crystallographic data for this paper. These data can be
56.1 (1C each, NCH2CC), 64.3, 64.5 (1C each, NCHCC). – obtained free of charge from the Cambridge Crystallographic
1
{ H}29Si NMR (59.6 MHz, [D6]DMSO): δ = 5.20 (2Si, Data Centre via www.ccdc.cam.ac.uk/data request/cif.
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C. Da¨schlein – C. Strohmann · Selective Si–O–Si Bond Cleavage
1565
Supplementary material
Acknowledgement
NMR spectra of 10 and additional crystallographic infor-
We are grateful to the Deutsche Forschungsgemeinschaft
mation are given as Supplementary Material available online for financial support. C. D. thanks the Studienstiftung des
(www.znaturforsch.com/ab/v64b/c64b.htm).
Deutschen Volkes for a doctoral scholarship.
[1] For some pioneering work concerning siloxanes,
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67, 963 – 965; b) D. T. Hurd, E. G. Rochow, J. Am.
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[2] For some examples concerning the physical and chem-
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[7] For general review articles concerning this topic, see:
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c) J. Beckmann, K. Jurkschat, Coord. Chem. Rev.
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d) J. Beckmann, M. Bieseman, K. Hassler, K. Ju-
rkschat, J. C. Martins, M. Schu¨rmann, R. Willem, In-
org. Chem. 1998, 37, 4891 – 4897; e) M. Schulte,
M. Schu¨rmann, D. Dakternieks, K. Jurkschat, Chem.
Commun. 1999, 1291 – 1292; f) J. Beckmann, K. Ju-
rkschat, M. Schu¨rmann, Organometallics 2001, 20,
5125 – 5133.
[3] For two examples, see: a) F. Baud-Grasset, J.-C. Palla,
patent registration DE69627324T2 11.12.2003, 2003;
b) M. Okamoto, K. Miyazaki, A. Kado, E. Suzuki,
Chem. Commun. 2001, 1838 – 1839.
[4] C. Da¨schlein, J. O. Bauer, C. Strohmann, Angew.
Chem. 2009, 121, 8218 – 8221; Angew. Chem. Int. Ed.
2009, 48, 8074 – 8077.
[8] For some examples on our aminomethyl-
functionalized silanes, see: a) C. Strohmann,
C. Da¨schlein, M. Kellert, D. Auer, Angew. Chem.
2007, 119, 4864 – 4866; Angew. Chem. Int. Ed. 2007,
46, 4780 – 4782; b) C. Da¨schlein, V. H. Gessner,
C. Strohmann, Acta Crystallogr., Sect. E: Struct
Rep. Online 2008, E64, o1950; c) C. Strohmann,
C. Da¨schlein, Organometallics 2008, 27, 2499 – 2504;
d) H. Ott, C. Da¨schlein, D. Leusser, D. Schildbach,
T. Seibel, D. Stalke, C. Strohmann, J. Am. Chem.
Soc. 2008, 130, 11901 – 11911; e) C. Strohmann,
J. Ho¨rnig, D. Auer, Chem. Commun. 2002, 766 – 767;
f) C. Strohmann, M. Bindl, V. C. Vraaß, J. Ho¨rnig,
Angew. Chem. 2004, 116, 1029 – 1032; Angew. Chem.
Int. Ed. 2004, 43, 1011 – 1014.
[9] For some review on our amino-functionalized silanes,
see: a) C. Strohmann, C. Da¨schlein, D. Auer, J. Am.
Chem. Soc. 2006, 128, 704 – 705; b) C. Da¨schlein,
C. Strohmann, Eur. J. Inorg. Chem. 2009, 43 – 52;
c) C. Strohmann, C. Da¨schlein, Chem. Commun. 2008,
2791 – 2793; d) C. Strohmann, O. Ulbrich, D. Auer,
Eur. J. Inorg. Chem. 2001, 4, 1013 – 1018.
[5] For selected examples concerning the high instabil-
ity of molecular metallasilanoles against hydrolysis,
see: a) F. Schindler, H. Schmidbaur, Angew. Chem.
1967, 79, 697 – 708; Angew. Chem., Int. Ed. Engl.
1967, 6, 683 – 694; b) H. Schmidbaur, Angew. Chem.
1965, 77, 206 – 216; Angew. Chem., Int. Ed. Engl.
1965, 6, 201 – 211; c) H. Schmidbaur, M. Schmidt,
Chem. Ber. 1961, 94, 1138 – 1142; d) H. Schmidbaur,
H.-S. Arnold, E. Beinhofer, Chem. Ber. 1964, 97, 449 –
458; e) H. Schmidbaur, F. Schindler, Chem. Ber. 1966,
99, 2178 – 2186; f) H. Schmidbaur, Chem. Ber. 1964,
97, 459 – 466; g) H. Schmidbaur, M. Schmidt, Angew.
Chem. 1962, 74, 589; Angew. Chem., Int. Ed. Engl.
1962, 1, 549; h) H. Schmidbaur, M. Schmidt, Angew.
Chem. 1961, 73, 655; i) H. Schmidbaur, M. Schmidt,
Chem. Ber. 1961, 94, 2137 – 2142; j) B. Armer,
H. Schmidbaur, Chem. Ber. 1968, 101, 2256 – 2267;
k) B. Armer, H. Schmidbaur, Chem. Ber. 1967, 100,
1521 – 1535; l) M. Schmidt, H. Schmidbaur, Angew.
Chem. 1958, 70, 704.
[10] For some review articles concerning the precoordi-
nation of metals by amino side arms, see: a) V. H.
Gessner, C. Da¨schlein, C. Strohmann, Chem. Eur. J.
2009, 15, 3320 – 3334; b) C. M. Whisler, S. MacNeil,
V. Snieckus, P. Beak, Angew. Chem. 2004, 116, 2256 –
2276; Angew. Chem. Int. Ed. 2004, 43, 2206 – 2225;
c) P. Beak, A. I. Meyers, Acc. Chem. Res. 1986, 19,
356 – 363.
[6] For examples concerning lithiosilanolates, see:
a) H.-W. Lerner, S. Scholz, N. Wiberg, K. Polborn,
M. Bolte, M. Wagner, Z. Anorg. Allg. Chem. 2005,
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1566
C. Da¨schlein – C. Strohmann · Selective Si–O–Si Bond Cleavage
[11] For some examples concerning coordination com-
pounds of zinc (tetra-, penta- and hexa-fold coordi-
nated zinc), see: a) F. Meyer, Eur. J. Inorg. Chem.
2006, 3789 – 3800; b) B. Bauer-Siebenlist, S. Dechert,
F. Meyer, Chem. Eur. J. 2005, 11, 5343 – 5352;
c) B. Bauer-Siebenlist, F. Meyer, E. Farkas, D. Vidovic,
S. Dechert, Chem. Eur. J. 2005, 11, 4349 – 4360.
[12] N. N. Greenwood, A. Earnshaw, Chemistry of the ele-
ments, 1st ed., Pergamon, Oxford 1984.
[14] Detailed examples concerning the stabilizing effects of
charge separation on amino acids can be found in all
commonly used text books of organic chemistry.
[15] G. M. Sheldrick, SHELXS-90, Program for the Solution
of Crystal Structures, University of Go¨ttingen, Go¨ttin-
gen (Germany) 1990.
[16] G. M. Sheldrick, SHELXL-97, Program for the Refine-
ment of Crystal Structures, University of Go¨ttingen,
Go¨ttingen (Germany) 1997. See also: G. M. Sheldrick,
Acta Crystallogr. 2008, A64, 112 – 122.
[13] For one current of the countless examples, see: M. F.
Bush, J. Oomens, R. J. Saykally, E. R. Williams, J. Am.
Chem. Soc. 2008, 130, 6463 – 6471.
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Supporting information (crystal-structure determination) belonging to the publication
“Selective Si–O–Si Bond Cleavage as Synthetic Access to
Functionalized, Hydrolysis-stable Zinc Silanolates”
Christian Däschlein and Carsten Strohmann*
Anorganische Chemie, Technische Universität Dortmund, Otto-Hahn-Straße 6, 44227 Dortmund,
Germany
Fax: (+49)231-755-7062, E-mail: mail@carsten-strohmann.de
Index
Crystal Structure Determination
P1
a) Crystallographic Data of compound 9
P3
P4
P6
P8
b) Crystallographic Data of compound 10
c) Crystallographic Data of compound (R,R)-11
d) Crystallographic Data of compound 12
NMR-Spectra of compound 10
P10
P13
Literature
Crystal-Structure Determination
Crystal structure determinations of 9 and 10 were accomplished on a Bruker APEX diffractometer (D8
three-circle goniometer) (Bruker AXS); data collection, cell determination and refinement: Smart
version 5.622 (Bruker AXS, 2001); integration: SaintPlus version 6.02 (Bruker AXS, 1999); empirical
absorption correction: Sadabs version 2.01 (Bruker AXS, 1999). Crystal structure determinations of
(R,R)-11 and 12 were accomplished on a Oxford-CCD diffractometer; data collection: CrysAlis
(Oxford, 2008); cell determination and refinement: CrysAlis RED (Oxford 2008); empirical absorption
correction. The structures were solved by applying direct and Fourier methods, using SHELXS-90[1]
and SHELXL-97[2]. The crystals were mounted at room temperature, the crystal structure
1
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determination was effected at –100 °C (type of radiation: Mo-Kα, λ = 0.71073 Å). The non-hydrogen
atoms were refined anisotropically. All of the H-atoms – except the ones located at the nitrogen atoms
– were placed in geometrically calculated positions and each was assigned a fixed isotropic
displacement parameter based on a riding-model. The hydrogen-atoms located at the nitrogens of the
(aminomethyl)-groups were found and could be freely refined in the Fourier-Map. CCDC 743382 (9),
CCDC 743383 (10), CCDC 743384 [(R,R)-11] and CCDC 743385 (12) contain the supplementary
crystallographic data for this paper. These data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
Tab. 1
Crystal Data and Structural Refinement Details for compounds 9, 10, (R,R)-11 and 12.
Compound
Formula
9
10
(R,R)-11
12
C16H38Si2N2O2Cl4Zn2 C36H46Si2N2O2Zn2Br4 C16H38Si2N2O2Zn2Br4 C20H46Si2N2O2Zn2Br4
Mr, g·mol–1
Cryst. size, mm3
Crystal system
Space group (Nr.)
a, Å
619.20
0.40 x 0.20 x 0.20
Monoclinic
P21/n (14)
9.0390(8)
14.6022(13)
10.3123(9)
96.3314(17)
1352.8(2)
2
1045.31
0.40 x 0.40 x 0.20
Monoclinic
P21/c (14)
9.919(3)
14.318(3)
14.853(4)
96.935(4)
2094.0(9)
2
797.04
0.30 x 0.10 x 0.10
Monoclinic
P21 (4)
853.14
0.20 x 0.10 x 0.10
Orthorhombic
P42/n (86)
18.6763(4)
18.6763(4)
10.1785(6)
90
9.4749(3)
14.8840(5)
10.2967(4)
96.779(3)
1441.93(9)
2
b, Å
c, Å
β, deg
V, Å3
3550.3(2)
4
Z
Dcalcd, g·cm–3
1.520
1.658
1.836
1.596
1
 (MoK), mm
2.271
5.051
7.303
5.938
F(000), e
Theta range θ, deg
hkl range
640
1040
784
1696
2.43 – 25.00
–10  h  10
–17  k  17
–12  l  12
28001
1.98 – 25.00
–11  h  11
–17  k  16
–16  l  17
11794
1.99 – 26.00
–11  h  11
–18  k  18
–12  l  12
27242
2.18 – 26.00
–22  h  23
–18  k  23
–12  l  11
30564
Refl. measured
Refl. unique
2383
3684
5640
3475
Rint
0.1092
0.0526
0.0638
0.0527
Structure refinement
Full-matrix least-squares on F2
R1 = 0.0344,
wR2 = 0.0669
R1 = 0.0516,
wR2 = 0.1239
R1 = 0.0385,
wR2 = 0.0820
R1 = 0.0428,
wR2 = 0.1281
Final R indices
[2sigma(I)]
R1 = 0.0512,
wR2 = 0.0732
R1 = 0.0797,
wR2 = 0.1305
R1 = 0.0522,
wR2 = 0.08382
R1 = 0.0734,
wR2 = 0.1333
R indices (all data)
x(Flack)
Goodness-of-fit on F2
-
-
–0.011(12)
1.010
-
1.033
1.052
1.019
Data/restraints/parameter
2383 / 0 / 133
3684 / 0 / 221
5640 / 1 / 267
3475 / 0 / 154
largest diff. peak and
hole, e·Å–3
0.323 and –0.288
2.196 and –1.284
0.905 and –0.612
1.580 and –0.438
2
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a) Crystallographic Data of compound 9
Cl1
C5'
Cl2
C4'
N'
C1
C6'
H1n'
C3'
Zn
C2'
O'
Si
C7'
Si'
C8'
C8
C7
O
C2
H1n
C6
C5
C3
Zn'
N
C1'
C4
Cl2'
Cl1'
Fig.1
ORTEP plot of the asymmetric unit of compound 9 at 50 % probability level.
Numbering scheme of H atoms (except H1n and H1n’, located at the nitrogens)
omitted for clarity.
Tab. 2
Atomic coordinates (x 104) and equivalent isotropic displacement parameters (Å2 x
103) for compound 9.
atom
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
Cl(1)
Cl(2)
N
x
y
z
U(eq)
42(1)
41(1)
34(1)
49(1)
49(1)
44(1)
40(1)
33(1)
41(1)
51(1)
28(1)
28(1)
26(1)
28(1)
8577(4)
6321(4)
6562(4)
6310(4)
7089(4)
8319(4)
9390(4)
8610(4)
11751(1)
12404(1)
7364(3)
8960(2)
7698(1)
11138(1)
7401(2)
8682(3)
8696(3)
9193(3)
9543(3)
8898(3)
8757(3)
8403(2)
8888(1)
8662(1)
9032(2)
9337(1)
8546(1)
9303(1)
–28(4)
–1533(3)
1356(3)
3611(4)
4876(4)
5417(4)
4398(3)
3126(3)
–2010(1)
1680(1)
2613(3)
37(2)
O
Si
–72(1)
Zn
–26(1)
3
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Tab. 3
Anisotropic Displacement parameters (Å2·103) compound 9.
atom
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
Cl(1)
Cl(2)
N
U11
U22
U33
U23
–7(2)
1(2)
U13
3(2)
U12
40(2)
37(2)
24(2)
30(2)
48(2)
46(2)
36(2)
32(2)
51(1)
38(1)
23(2)
20(1)
23(1)
21(1)
29(2)
48(3)
44(2)
82(3)
65(3)
53(3)
41(2)
28(2)
30(1)
55(1)
31(2)
24(1)
26(1)
25(1)
58(3)
37(2)
32(2)
37(2)
37(2)
33(2)
40(2)
39(2)
45(1)
58(1)
31(2)
42(1)
30(1)
37(1)
–1(2)
–5(2)
–6(2)
11(2)
9(2)
1(2)
0(2)
0(2)
1(2)
12(2)
12(2)
0(2)
–4(2)
3(2)
–1(2)
3(2)
–3(2)
–3(2)
–2(1)
24(1)
4(1)
–3(2)
6(2)
4(2)
16(1)
–7(1)
10(1)
5(1)
5(1)
2(1)
–2(1)
–1(1)
–3(1)
1(1)
O
1(1)
Si
–1(1)
4(1)
3(1)
Zn
5(1)
b) Crystallographic Data of compound 10
C4
C5
C3
C2
C16'
C17'
C18'
C15'
C14'
C6
Br2
H1n'
Br1'
C1
Si1
C11
C12
C7
C8
N1'
C13'
C8'
Zn1
O1
Br1
H1n
C10
C9
O1'
C9'
C10'
C13
C14
Zn1'
C1'
Si1'
C7'
N1
C12'
C11'
C6'
C5'
Br2'
C18
C17
C15
C2'
C3'
C4'
C16
Fig.2
ORTEP plot of the asymmetric unit of compound 10 at 50 % probability level.
Numbering scheme of H atoms (except H1n and H1n’, located at the nitrogens)
omitted for clarity.
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Tab. 4
Atomic coordinates (x 104) and equivalent isotropic displacement parameters (Å2 x
103) for compound 10.
atom
Br(1)
Br(2)
C(1)
x
y
z
U(eq)
88(1)
63(1)
37(2)
46(2)
60(2)
65(2)
67(2)
53(2)
33(1)
42(2)
51(2)
53(2)
52(2)
42(2)
34(2)
55(2)
64(2)
64(2)
54(2)
43(2)
34(1)
32(1)
32(1)
41(1)
2474(1)
6345(1)
7053(6)
8006(7)
9365(7)
9801(8)
8901(8)
7513(7)
4229(6)
3442(6)
2741(7)
2859(7)
3593(6)
4284(7)
4721(6)
2188(6)
896(7)
6623(1)
7008(1)
4259(4)
4824(5)
4817(5)
4241(6)
3668(6)
3676(5)
4929(4)
5688(4)
6173(5)
5860(5)
5076(5)
4621(5)
2999(4)
3239(5)
2956(5)
1898(6)
1371(5)
1678(4)
2722(3)
4695(3)
4283(1)
5919(1)
74(1)
834(1)
2377(4)
2024(4)
2400(6)
3116(6)
3455(5)
3088(5)
2696(4)
2470(4)
3094(5)
3974(5)
4212(4)
3596(4)
1870(4)
1657(5)
1078(5)
1145(5)
851(5)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
N(1)
660(7)
1858(7)
3187(7)
3382(5)
4933(4)
5213(2)
4591(1)
1410(4)
1356(4)
882(2)
O(1)
Si(1)
Zn(1)
1893(1)
268(1)
Tab. 5
Anisotropic Displacement parameters (Å2·103) compound 10.
atom
Br(1)
Br(2)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
U11
88(1)
107(1)
40(4)
43(4)
36(4)
41(4)
63(6)
49(5)
34(3)
40(4)
42(4)
45(4)
U22
113(1)
45(1)
38(4)
46(4)
62(5)
78(6)
74(6)
58(5)
29(3)
45(4)
43(4)
70(5)
U33
U23
–5(1)
–6(1)
–6(3)
–6(3)
–22(5)
–21(5)
–5(4)
–7(4)
0(3)
U13
U12
62(1)
–24(1)
1(3)
59(1)
38(1)
31(4)
50(4)
82(6)
73(6)
56(5)
50(5)
37(4)
42(4)
71(5)
47(5)
–5(1)
13(1)
–1(3)
2(3)
2(3)
6(4)
–3(4)
12(5)
19(5)
3(4)
–9(4)
–25(4)
–2(4)
2(3)
–4(3)
0(3)
6(3)
6(3)
–4(4)
–14(4)
14(4)
15(3)
2(3)
–2(4)
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C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
N(1)
47(4)
49(4)
31(3)
40(4)
43(4)
39(4)
53(5)
50(4)
37(3)
40(2)
35(1)
58(1)
77(5)
44(4)
38(4)
57(5)
69(6)
83(6)
56(5)
31(4)
34(3)
29(2)
30(1)
33(1)
32(4)
35(4)
34(4)
69(5)
76(6)
71(5)
51(5)
48(4)
32(3)
27(2)
29(1)
33(1)
6(4)
–1(3)
–1(3)
–18(4)
–19(4)
–20(5)
–8(4)
0(3)
7(3)
5(3)
2(3)
7(4)
–14(4)
6(4)
4(4)
8(3)
2(2)
3(2)
2(1)
7(1)
–1(4)
0(3)
2(3)
7(4)
6(4)
–17(4)
–18(4)
–5(3)
–3(2)
0(2)
0(2)
O(1)
2(2)
Si(1)
1(1)
–1(1)
9(1)
Zn(1)
3(1)
c) Crystallographic Data of compound (R,R)-11
C13
C12
Br3
C14
C1
C10
O2
Zn2
Br4
O1
C15
N2
C4
C3
H2N
Si2
Si1
C11
C16
H1N
N1
Br2
C2
C5
Zn1
C9
C7
C6
C8
Br1
Fig.3
ORTEP plot of the asymmetric unit of compound (R,R)-11 at 50 % probability level.
Numbering scheme of H atoms (except H1n and H2n, located at the nitrogens)
omitted for clarity.
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Tab. 6
Atomic coordinates (x 104) and equivalent isotropic displacement parameters (Å2 x
103) for compound (R,R)-11.
atom
Br(1)
Br(2)
Br(3)
Br(4)
C(1)
x
y
z
U(eq)
56(1)
50(1)
44(1)
37(1)
49(2)
46(2)
36(2)
78(3)
114(5)
96(4)
55(2)
84(3)
45(2)
38(2)
32(2)
31(2)
42(2)
44(2)
38(2)
46(2)
39(2)
28(1)
25(1)
26(1)
27(1)
28(1)
28(1)
26(1)
5249(1)
3789(1)
18(1)
8534(1)
8099(1)
5778(1)
5857(1)
8392(6)
9609(5)
8254(5)
7609(6)
7738(8)
8638(7)
8637(6)
8336(7)
5868(6)
4528(5)
5672(5)
5298(5)
5485(5)
5957(5)
5871(5)
6577(5)
7943(4)
5892(4)
7716(3)
6420(3)
8482(1)
5641(1)
7746(1)
6379(1)
8691(1)
4960(1)
5815(1)
9690(1)
5979(7)
7632(8)
8860(7)
11072(8)
12363(9)
12250(9)
10881(9)
11046(11)
8822(6)
7645(7)
5923(6)
4414(6)
2997(7)
2383(7)
3435(6)
3359(7)
10145(6)
4704(5)
7596(4)
7332(4)
7494(2)
7458(2)
7212(1)
7561(1)
1150(1)
–833(8)
1229(8)
–736(7)
–1043(11)
–339(15)
274(13)
931(9)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
2344(10)
6238(7)
3959(8)
5748(7)
3524(7)
2959(8)
4213(7)
5504(7)
6615(7)
24(7)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
N(1)
N(2)
4796(6)
1638(4)
3597(4)
411(2)
O(1)
O(2)
Si(1)
Si(2)
Zn(1)
Zn(2)
4808(2)
3638(1)
1539(1)
Tab. 7
Anisotropic Displacement parameters (Å2·103) compound (R,R)-11.
atom
Br(1)
Br(2)
Br(3)
Br(4)
C(1)
C(2)
C(3)
C(4)
U11
39(1)
76(1)
34(1)
57(1)
61(6)
53(5)
31(4)
125(9)
U22
U33
U23
–16(1)
10(1)
–16(1)
2(1)
U13
–14(1)
24(1)
–7(1)
10(1)
–1(4)
8(4)
U12
–7(1)
5(1)
45(1)
30(1)
48(1)
24(1)
51(5)
24(4)
42(5)
63(6)
79(1)
47(1)
46(1)
32(1)
33(4)
61(5)
37(4)
56(6)
–3(1)
–4(1)
26(4)
3(4)
3(4)
5(4)
–1(4)
16(5)
6(3)
8(3)
52(7)
8(6)
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C(5)
C(6)
231(16)
168(12)
63(6)
48(6)
40(4)
42(4)
23(3)
26(4)
39(4)
51(5)
39(4)
34(4)
55(4)
32(3)
17(2)
23(2)
28(1)
28(1)
24(1)
25(1)
73(8)
76(8)
36(5)
87(8)
54(5)
32(4)
25(4)
36(4)
44(5)
40(5)
43(4)
49(5)
35(4)
24(3)
24(2)
21(2)
27(1)
25(1)
22(1)
22(1)
37(6)
46(6)
63(6)
115(9)
37(4)
41(5)
43(4)
29(4)
39(4)
39(4)
31(4)
56(5)
26(3)
27(3)
35(3)
34(3)
27(1)
30(1)
38(1)
30(1)
–12(5)
–6(6)
–13(4)
–20(7)
–3(4)
6(4)
19(8)
25(7)
–8(5)
–2(6)
–9(4)
2(4)
–68(9)
46(8)
16(4)
–25(5)
12(4)
12(3)
1(3)
C(7)
C(8)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
N(1)
–4(3)
–5(3)
–2(4)
–3(4)
–11(4)
1(4)
–8(3)
–4(3)
–7(4)
1(4)
–7(3)
7(3)
–8(4)
–15(4)
–8(4)
8(3)
6(3)
12(4)
3(3)
–7(3)
0(3)
N(2)
4(2)
3(3)
O(1)
–1(2)
–2(2)
2(1)
2(2)
2(2)
O(2)
–1(2)
4(1)
1(2)
Si(1)
Si(2)
Zn(1)
Zn(2)
8(1)
1(1)
–3(1)
3(1)
7(1)
–1(1)
–2(1)
0(1)
2(1)
–1(1)
d) Crystallographic Data of compound 12
Br2
C10'
Br1
C2
C5
C8'
Zn
C4
Si
C9'
N'
N
C1'
Si'
C3
C6
C7
C7'
C6'
O5
O
H1n
C1
C3'
H1n'
C9
C4'
C5'
Zn'
C8
Br1'
C10
Br2'
C2'
Fig.4
ORTEP plot of the asymmetric unit of compound 12 at 50 % probability level.
Numbering scheme of H atoms (except H1n and H1n’, located at the nitrogen) omitted
for clarity.
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Tab. 8
Atomic coordinates (x 104) and equivalent isotropic displacement parameters (Å2 x
103) for compound 12.
atom
Br(1)
Br(2)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
N
x
y
z
U(eq)
48(1)
37(1)
54(3)
51(3)
30(2)
39(3)
42(3)
52(4)
69(3)
75(5)
45(3)
49(3)
34(2)
29(1)
32(1)
31(1)
8473(1)
8583(1)
10675(6)
9061(6)
9929(5)
9321(5)
8596(5)
9327(6)
10002(6)
10647(8)
10652(5)
11276(5)
9950(4)
9954(4)
9903(1)
9223(1)
5111(1)
4944(1)
2900(6)
3074(6)
3728(4)
3159(6)
3027(5)
3793(6)
3831(6)
3800(8)
3118(6)
3054(6)
3148(3)
4283(2)
3493(1)
5036(1)
8125(1)
12025(1)
9626(11)
9665(11)
7363(8)
5401(11)
6166(10)
4595(13)
3757(12)
4697(14)
5548(12)
6408(11)
6314(7)
9824(5)
9178(3)
9974(1)
O
Si
Zn
Tab. 9
Anisotropic Displacement parameters (Å2·103) for compound 12.
atom
Br(1)
Br(2)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
N
U11
43(1)
29(1)
90(9)
91(9)
22(5)
37(6)
36(5)
46(7)
58(7)
59(10)
42(7)
40(6)
36(4)
21(3)
38(2)
23(1)
U22
54(1)
38(1)
25(6)
31(6)
33(4)
48(7)
52(7)
50(7)
87(7)
106(13)
41(7)
55(7)
32(4)
29(3)
23(1)
28(1)
U33
46(1)
46(1)
48(8)
33(7)
35(6)
32(7)
39(8)
60(9)
62(9)
61(11)
52(8)
52(8)
35(5)
36(4)
34(2)
42(1)
U23
–4(1)
–1(1)
–2(5)
–18(5)
–10(4)
–2(6)
4(5)
U13
–6(1)
11(1)
–8(7)
16(6)
9(4)
U12
3(1)
–3(1)
5(5)
–23(6)
–7(4)
–8(5)
–1(5)
5(5)
–2(5)
–17(5)
–9(6)
31(8)
5(8)
43(7)
29(7)
–37(10)
3(6)
6(7)
–1(7)
–10(5)
5(5)
14(6)
8(5)
–3(6)
–4(3)
–13(2)
–4(1)
–7(1)
0(4)
–16(4)
4(3)
O
2(3)
Si
5(1)
–3(1)
1(1)
Zn
5(1)
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NMR-Spectra of compound 10
Fig. 5
Numbering scheme of compound 10.
1.) NMR-Spectra of the disiloxane 10 in solution (solvent: DMSO-d6).
Fig. 6
Complete 29Si spectrum.
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Fig. 7
Complete 13C spectrum.
Fig. 8
Complete 1H spectrum.
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2.) NMR-Spectra of the disiloxane 10 in the solid state.
Fig. 9
Complete 29Si spectrum.
Fig. 10
Complete 13C spectrum.
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Fig. 11
Complete 15N spectrum.
Literature
[1]
[2]
G. M. Sheldrick, SHELXS-90, A Program for the Solution of Crystal Structures, Universität
Göttingen 1990.
G. M. Sheldrick, SHELXL-97, A Program for Crystal Structure Refinement, Universität
Göttingen 1997.
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