Synthesis of 10-Methylsulfide and 10-Alkylmethylsulfonium nido-Carborane Derivatives: B–H···π Interactions between the B–H–B Hydrogen Atom and Alkyne Group in 10-RC≡CCH2S(Me)-7,8-C2B9H11

Article abstract of DOI:10.1002/ejic.201700785

The 10-dimethylsulfonium derivative of nido-carborane 10-Me₂S-7,8-C₂B₉H₁₁ was prepared by reaction of the protonated form of nido-carborane with dimethylsulfide in toluene. Its partial demethylation with sodium amide in toluene gave the corresponding 10-methylsulfide derivative [10-MeS-7,8-C₂B₉H₁₁]^–. This 10-methylsulfide derivative was alkylated with various alkylating agents to produce a series of 10-alkylmethylsulfonium derivatives 10-R(Me)S-7,8-C₂B₉H₁₁ (R = Et, Pr, Bu, CH₂CH=CH₂, CH₂Ph, CH₂C≡CH, CH₂C≡CPh, CH₂C≡CSiMe₃). The ¹¹B NMR spectra of the latter three compounds containing an acetylene group demonstrate unusually strong signal splitting that can be explained by strong intramolecular B–H···π(C≡C) interactions. The existence of such interactions in the solid state was supported by the X-ray crystal structure of 10-HC≡CCH₂(Me)S-7,8-C₂B₉H₁₁ with a short B–H···C(C≡C) distance of 2.658 ?. This is the first example of B–H···π(C≡C) hydrogen bonding.

Full text of DOI:10.1002/ejic.201700785

A Journal of
Accepted Article
Title: Synthesis of 10-Methylsulfide and 10-Alkylmethylsulfonium nido-
Carborane Derivatives. B-H…π Interactions between the B-
H-B Hydrogen and Alkyne Group in 10-RC≡CCH2S(Me)-7,8-
C2B9H11
Authors: Sergey A. Anufriev, Igor B. Sivaev, Kyrill Yu. Suponitsky, Ivan
A. Godovikov, and Vladimir I. Bregadze
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To be cited as: Eur. J. Inorg. Chem. 10.1002/ejic.201700785
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10.1002/ejic.201700785
European Journal of Inorganic Chemistry
Synthesis of 10-Methylsulfide and 10-Alkylmethylsulfonium nido-Carborane
Derivatives. B-H…π Interactions between the B-H-B Hydrogen and Alkyne
Group in 10-RC≡CCH2S(Me)-7,8-C2B9H11
Sergey A. Anufriev, Igor B. Sivaev*, Kyrill Yu. Suponitsky, Ivan A. Godovikov, Vladimir I.
Bregadze
A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences,
Vavilov Str. 28, 119991, Moscow, Russia
Abstract
10-Dimethylsulfonium derivative of nido-carborane 10-Me2S-7,8-C2B9H11 was prepared
by reaction of the protonated form of nido-carborane with dimethylsulfide in toluene. Its partial
demethylation with sodium amide in toluene gave the corresponding 10-methylsulfide derivative
[10-MeS-7,8-C2B9H11]-. The last one was alkylated with various alkylating agents to produce a
series of 10-alkylmethylsulfonium derivatives 10-R(Me)S-7,8-C2B9H11 (R = Et, Pr, Bu, All, Bn,
CH2C≡CH, CH2C≡CPh, CH2C≡CSiMe3). The 11B NMR spectra of the last three compounds
containing acetylene group demonstrate unusually strong signal splitting that can be explained
by strong intramolecular B-H…π(C≡C) interactions. The existence of such interactions in the
solid state was supported by X-ray crystal structure of 10-HC≡CCH2(Me)S-7,8-C2B9H11 with
short B-H…C(C≡C) distance of 2.658 Å. This is the first example of the B-H…π(C≡C)
hydrogen bonding.
Keywords: carborane; sulfonium derivatives; intramolecular B-H…π(C≡C) bonding; NMR
spectroscopy; X-ray structure
Introduction
The synthesis of polyhedral boranes, carboranes and metallaboranes was one of the major
highlights in the development of inorganic chemistry over the last century [1]. Currently the
carborane chemistry is growing at an accelerating pace and generates more than 300 new
publications each year, many of them reporting new advances in medicine, nanomaterials, and
other applications [2,3]. The past decade demonstrates a growing interest in various aspects of
* E-mail: sivaev@ineos.ac.ru
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10.1002/ejic.201700785
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medicinal chemistry of carboranes [4,5] including their use as pharmacophores in drug design
[6-8], HIV protease inhibitors [9], radionuclide imaging [10] and boron neutron capture therapy
of cancer [11-13].
The general approach to synthesis of carborane-based compounds for BNCT and
radionuclide diagnostics lies in derivatization at one of the CH vertices of the carborane cage [2].
The substituent introduced may be a biologically active moiety that acts as a tumor-targeting
vector, or a simple functional group (-COOH, -NH2, -N3, -NCO, -NCS) that could be used for
conjugation with high molecular weight biomolecules using standard methods of bioorganic
chemistry. The CH groups in carboranes are weakly acidic and can be deprotonated by strong
bases such as alkyllithium or Grignard reagents to give the corresponding C-metalated
carboranes which are rather nucleophilic to react with active electrophiles (alkyl halides,
aldehydes, etc.); however the synthetic utility of C-metalated carboranes is some limited due to
their basic character and ability to react many organic CH-acids including aliphatic esters and
nitriles. Therefore the preliminary introduction of strongly acidic mercapto group followed by its
alkylation was proposed recently to avoid this problem. In such a way, a variety of functional
derivatives of closo-carborane 1-R(CH2)nS-1,2-C2B10H11 as well as their nido-analogues [7-
R(CH2)nS-7,8-C2B9H11]- were synthesized [14-17].
Another approach includes alkylation of 9-methylthio derivative of nido-carborane [9-
MeS-7,8-C2B9H11]- to give the corresponding 9-alkylmethylsulfonium derivatives 9-
R(CH2)n(Me)S-7,8-C2B9H11 [18-20]. In contrast to the B-dialkylsulfonium derivatives of other
polyhedral boron hydrides where racemization at the sulfur atom proceeds very fast already at
ambient temperature [21], in the case of nido-carborane derivatives 9-R(CH2)n(Me)S-7,8-
C2B9H11 the activation barrier is much higher due to an interaction of the sulfur lone pair with
the B(9)-B(10) antibonding orbital of the nido-carborane cage [22] and no racemization is
observed up to 333 K [20]. As a result the asymmetrically substituted nido-carborane derivatives
9-R(CH2)n(Me)S-7,8-C2B9H11 exist as mixtures of diastereomers which are not very suitable for
their medical applications.
In this contribution we describe preparation of the symmetrically substituted 10-
methylsulfide derivative of nido-carborane [10-MeS-7,8-C2B9H11]- as well as synthesis of new
10-alkylmethyl sulfonium derivatives 10-R(Me)S-7,8-C2B9H11 based thereof.
Results and Discussion.
Synthesis of 10-Me2S-7,8-C2B9H11 and [10-MeS-7,8-C2B9H11]-. There are two different
synthetic approaches to the 10-methylsulfide derivative of nido-carborane [10-MeS-7,8-
2
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10.1002/ejic.201700785
European Journal of Inorganic Chemistry
C2B9H11]-. The first one consists in preparation of the corresponding thiol followed by its
methylation. The N,N-dimethylthioacetamide derivative 10-Me2NC(Me)S-7,8-C2B9H11 [23]
could serve as intermediate in synthesis of the thiol derivative, however low yield (25 %) of this
compounds preclude it further use. Our recent attempt to use with this goal the corresponding S-
thiuronium derivative 10-(Me2N)2CS-7,8-C2B9H11 was failed due to formation of non-separable
mixture of 9- and 10-isomers [24]. The second approach includes preparation of the
corresponding dimethylsulfonium derivative followed by its partial demethylation. The 10-
dimethylsulfonium derivative of nido-carborane 10-Me2S-7,8-C2B9H11 (1) has been prepared for
the first time by the reaction of the potasium salt of the parent nido-carborane with
dimethylsulfide in a mixture of water and toluene in the presence of acid and acetaldehyde [25].
The mechanism of this reaction is not clear and it prompted us to elaborate a new synthetic
procedure for synthesis of 1. With this goal we used approach that was proposed earlier for
synthesis of the relative oxonium derivative 10-O(CH2CH2)2O-7,8-C2B9H11 [26]. The protonated
form of nido-carborane 7,8-C2B9H13 was prepared by the treatment of (Me3NH)[7,8-C2B9H12]
with sulfuric acid in toluene and reacted with dimethylsulfide to give the desired
dimethylsulfonium derivative 1 in 76 % yield (Scheme 1). The reaction mechanism can be
described as the acid-assisted nucleophilic substitution (AANS) [27].
+
H
-
-
H
Me2S
1. H+, toluene
2. Me2S
1
CH
BH
B
C1.HH+,tol.Me2
C.H,+tol.Me2
Scheme 1
The 10-methylthio derivative [10-MeS-7,8-C2B9H11]- (2) was prepared by demethylation
of the 10-dimethylsulfonium derivative 1 with sodium amide in refluxing toluene and isolated as
the tetrabutylammonium salt in a manner described earlier for the isomeric 9-methylthio
derivative [9-MeS-7,8-C2B9H11]- [20] (Scheme 2). It should be noted, that the 10-methylthio
derivative 2 is less stable than the corresponding 9-methylthio derivative and decomposes slowly
in the solid state and some faster in a solution.
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10.1002/ejic.201700785
European Journal of Inorganic Chemistry
+
H
H
-
-
Me2S
1. NaNH2, toluene MeS
reflux
2. (Bu4N)Br, water
2
1
Scheme 2
1
The demethylation results in the high field shift of the MeS signal in the H NMR
11
spectrum of 2 from 2.72 ppm to 2.07 ppm. The pattern of the B NMR spectrum transforms
from 2 : 2 : 1 : 2 : 1 : 1 for 1 to 2 : 2 : 1 : 1 : 2 : 1 for 2 due to the low field shift of the signal
corresponding to the substituted B(10) atom from -25.8 to -21.2 ppm, respectively.
It should be noted that the obtained 10-methylthio derivative is of interest not only for
synthesis of various functional derivatives (See below), but also as a building block in the design
of molecular machines [28].
Synthesis of alkylmethylsulfonium derivatives 10-R(Me)S-7,8-C2B9H11. The 10-
methylthio derivative 2 can be easily transformed to alkylmethylsulfonium derivatives 10-
R(Me)S-7,8-C2B9H11, where R = Et (3), Pr (4), Bu (5), All (6) or Bn (7), by heating with the
corresponding halogen alkanes (Scheme 3).
+
H
H
-
-
MeS
R(Me)S
RX, CHCl3
reflux
2
R = Et (3), Pr (4), Bu (5),
CH2CH=CH2 (6), CH2C6H5 (7)
Scheme 3
1
The H NMR spectra of 3-5 demonstrate the MeS signal at 2.48-2.49 ppm. The S-CH2
protons are magnetically non-equivalent therefore two different J(H-H) coupling constants, one
for the geminal protons (J2 ~ 12 Hz) and a second one for the neighbor CH3 or CH2 protons (J3 ~
1
8 Hz) are observed. The H NMR spectra of 6 and 7 also demonstrate magnetically non-
equivalent signals of the S-CH2 protons with J2(H-H) geminal coupling constants of 14 and 13
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10.1002/ejic.201700785
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13
Hz, respectively. The C NMR spectra of 3-7 in addition to resonances corresponding to the
substituents at the sulfur atom, display broad signals at ~ 46 ppm, which were attributed to the
cluster carbon atoms.
11
The B{1H} NMR spectra of 3-6 are similar to the spectrum of 1, except some signal
splitting at ~ -16 ppm corresponding to the B(5) and B(6) atoms, this splitting varies from 0.3 to
0.8 ppm and is absent completely in the 11B{1H} NMR spectrum of 7. It is known that the
signals of the B(5) and B(6) atoms in nido-carborane derivatives are very sensitive to the
position of the “extra” hydrogen atom [29] which can migrate over two bridge positions B(9)-H-
B(10) and B(10)-H-B(11) resulting in the equilibrium (Scheme 4). Therefore the presence of
non-equivalent substituents at the sulfur atom in the position 10 can shift slightly the equilibrium
position, producing in such a way splitting of B(5/6) signal in the 11B NMR spectrum. Such
effect was reported earlier for 10-Ph(Et)S-7,8-C2B9H11 [30], whereas no splitting was observed
in the case of 10-Et(Me)S-7,8-Ph2-7,8-C2B9H9 [31]. It means that substituents at the sulfur atom
in these compounds have only negligible interactions with the carborane cage.
+
+
+
H
H
H
-
-
-
R'RS
R'RS
R'RS
Scheme 4
10-RC≡CCH2(Me)S-7,8-C2B9H11 derivatives: the B-H…π interactions between the
bridging hydrogen atom and alkyne group. The reaction of 2 with propargyl bromide gives
the corresponding propargyl methylsulfonium derivative 10-HC≡CCH2(Me)S-7,8-C2B9H11 (8)
(Scheme 5). Surprisingly the 11B{1H} NMR spectrum of 8 demonstrates complete splitting of all
pairs of symmetrical boron atoms B(2/4), B(5/6) and B(9/11) in the carborane cage. Moreover,
the 13C{1H} NMR spectrum of 8 contain signals of two non-equivalent Ccarb carbon atoms of the
carborane cage at 45.8 and 47.1 ppm. It allows one to suggest rather strong interactions between
the substituent and the “extra” hydrogen atom, which prevents its free migration between the
B(9)-H-B(10) and B(10)-H-B(11) positions. Since the substituent has not functional groups other
than the alkyne group we supposed that the B-H…π(alkyne) interactions are responsible for such
11
13
11
unprecedented signal splitting in the B{1H} and С NMR spectra. The high temperature B
NMR study of 8 in DMSO-d6 demonstrated no signals coalescence at least up to 353 K, that
indicates rather strong interactions (ΔG≠ > 13 kcal/mol). On the first glance the interaction
between the BH hydride atom and electron-rich alkyne group should be repulsive rather than
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10.1002/ejic.201700785
European Journal of Inorganic Chemistry
attractive. However, in the contract to other BH hydrogens the bridge B-H-B hydrogen in the
nido-carboranes is weakly acidic (pKa 5.2 for 10-Me2S-7,8-C2B9H11 [32]) and therefore this
interaction can be considered as unconventional example of the classical intramolecular
hydrogen bonding [33].
We suggested that the similar bonding should exist in the derivatives with internal alkyne
group and synthesized two such derivatives 10-RC≡CCH2(Me)S-7,8-C2B9H11 (R = Ph (9), SiMe3
(10)) by the reaction of 2 with the corresponding mesylates (Scheme 5). Indeed, as it was
expected, the 11B{1H} and 13C NMR spectra of these derivatives also demonstrate characteristic
splitting of the corresponding signals with the maximum effect in the case of compound 10
containing strong electron-donating trimethylsilyl group (ΔB(5/6) = 4.4 ppm, ΔB(9/11) = 1.6 ppm,
ΔB(2/4) = 1.4 ppm, and ΔCcarb = 2.5 ppm) (Figure 1). Moreover, the 1H NMR spectrum of 10 was
found to contain signals of two non-equivalent CHcarb hydrogen atoms of the carborane cage at
2.22 and 2.25 ppm. This correlates well with an increase of electron density on the alkyne group
and thereby supports the conclusion that these B-H…π(alkyne) interactions should be considered
as classical hydrogen bonding. It is worth to note that the magnitudes of these signal splitting are
comparable with those caused by substitution of one CHcarb hydrogen atom by methyl or
methylthio groups (ΔB(5/6) = 1.2 and 0 ppm, ΔB(9/11) = 0.5 and 0.8 ppm, and ΔB(2/4) = 4.0 and 5.2
ppm for 7-Me-10-Me2S-7,8-C2B9H10 [30] and 7-MeS-10-Me2S-7,8-C2B9H10 [34], respectively),
that indicates strong intramolecular interactions.
+
RX, CHCl
X = Br or OMs
H
H
-
3
-
MeS
R(Me)S
reflux
R =
(8)
(9)
2
CH C CH
2
CH C CPh
2
(10)
CH C CSiMe
2
3
Scheme 5
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Figure 1. 11B{1H} NMR spectra of 10-Me2S-7,8-C2B9H11 (1) (a) and 10-
Me3SiC≡CCH2(Me)S-7,8-C2B9H11 (10) in chloroform-d.
The intermolecular X-H…π(C≡C) interactions in organic and organometallic compounds
are well known [35]. However, despite the fact that intramolecular hydrogen bonding is one of
the most studied non-covalent interactions of molecules, examples of the intramolecular X-
H…π(C≡C) hydrogen bonds are quite rare. In organic compounds, strong intramolecular X-
H…π(C≡C) bonding was found in arylacetylenes containing NH [36] or OH [37] donors in
ortho-position, whereas for compounds with flexible chains such as 3-butyn-1-ol [38] or 3-
hexyn-1,6-diol [39] the bonding is much weaker that results in mixtures of bonded and non-
bonded conformers. The similar weak intramolecular C-H…π(C≡C) interactions were revealed
in some aliphatic alkynes such as 1-pentyne and its derivatives [40]. In organometallic
complexes the intramolecular C-H…π(C≡C) interactions between ligands are caused by sterical
overcrowding at the metal atom [41]; as a rule these interactions are weak and are lost in
solution.
The existence of the intramolecular X-H…π(C≡C) hydrogen bonds in the solid (X-ray
diffraction), liquid (IR spectroscopy) and gaseous (electron diffraction) states is well
documented, however the direct evidences of such bonding in solutions are very rare [42]. We
7
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10.1002/ejic.201700785
European Journal of Inorganic Chemistry
believe that the described above splitting of signals in the 11B NMR spectra should be considered
as an indirect evidence of the formation of the intramolecular B-H…π(C≡C) hydrogen bonds in
solution. To prove this suggestion, the x-ray diffraction study of a series of the 10-R(Me)S-7,8-
C2B9H11 derivatives was curried out (See below).
Single crystal X-ray diffraction study. The solid state structures of compounds 7, 8 and
10 were determined by single crystal X-ray diffraction (Figures 2-4). In all structures one of
substituents at the sulfur atoms (Me in 7 and 10, and CH2C≡CH in 8) is turned in the direction of
the B(9)-B(10) boron edge bearing bridging hydrogen in such a way that the B(9)-B(10) and S-C
bonds lay nearly in the same plane (See Table 1) and two CH hydrogens are directed to the
B(9)H and B(5)H hydrogens (the CH…HB distances are 2.473-2.774 Å).
Figure 2. Molecular structure of 10-PhCH2(Me)S-7,8-C2B9H11 (7) with the atom
numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
Figure 3. Molecular structure of 10-HC≡CCH2(Me)S-7,8-C2B9H11 (8) with the atom
numbering scheme (displacement ellipsoids are drawn at the 50% probability level) - front view
(left) and top view (right).
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10.1002/ejic.201700785
European Journal of Inorganic Chemistry
Figure 4. Molecular structure of 10-Me3SiC≡CCH2(Me)S-7,8-C2B9H11 (10) with the
atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
Table 1. Selected bond distances and angles in structures 10-R(Me)S-7,8-C2B9H11.
Compound
B-S
S-C(Me)
S-C(R)
B(9)-B(10)- B(11)-B(10)-
S-C(Me)
5.9(2)
59.2(2)
5.0(2)
11.14
S-C(R)
53.5(2)
14.6(2)
55.3(2)
-
7
8
10
1.891(3)
1.894(2)
1.884(3)
1.895
1.785(2)
1.791(2)
1.768(2)
1.798
1.818(2)
1.832(2)
1.824(2)
-
10-Me2S-7,8-C2B9H11 [30]
1.804
55.25
The acetylenic fragment in the solid state structure of 8 is turned in such a way that it is
located over the B(9)-B(10) edge and forms shortened contact (2.658 Å) with the bridging
hydrogen atom H(12) (the distance from H(12) to the center of C(3)-C(4) triple bond is 2.803 Å,
that is less than the sum of van der Waals radii 2.87 Å [43]). To the best of our knowledge this is
the first example of the intramolecular B-H…π(C≡C) hydrogen bonding. The intramolecular B-
H…π(aryl) hydrogen bonds with participation of the B-H-B bridging hydrogens were found
earlier in metallaborane complexes with arylphosphine ligands 7-(Ph3P)-2,7:3,7-(PhCOS)2-7-
NiB10H10 [44], 6,6-(PhMe2P)2-6,6-(CO)2-5-Cl-6-MoB9H12 [45], 6,6,6-(PhMe2P)3-6-H-6-ReB9H13
[46].
In contrast to compound 8, the molecular conformation compound 10 in the crystal of is
so that no B-H…π(C≡C) contact is observed. It prompted us to carry out quantum chemical
investigation of molecule 10 at PBE0/6-311G(df,pd) level of theory which was adopted in our
recent studies of nonbonded interactions [20,47]. If we fix position of the extra-hydrogen over
one of B-B edges in the open pentagonal face of the dicarbollide ligand, we would have two
isomers I and II which differ in orientation of substituents at the sulfur atom (See Scheme 6). In
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10.1002/ejic.201700785
European Journal of Inorganic Chemistry
the solid state only isomer I was found, however the racemisation at sulfur atom in B-
alkylsulfonium derivatives of polyhedral boron hydrides is known to proceed very fast already at
ambient temperature due to its very low activation energy (ΔG298 < 1 kcal/mol) [21].
Me
+
H
Me3Si
-
S
I
Me3Si
+
H
-
S
Me
II
Scheme 6
It is clear that isomer I can not form the H(12)…C(2) close contact even though it would
adopt conformation with the CC fragment located above the carborane cage. However for
isomer II, such B-H…π(C≡C) interaction can be formed if the B-S-C-C torsion angle is close to
60°. To find whether the above statement is true, we have optimized molecular conformations of
both isomers. The optimized geometry of isomer I (Figure 5) is close to the experimental one (B-
S-C-C is 171.1°; experimental value is 163.1(2)°).
Figure 5. General view of the optimized conformers of isomers I and II.
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10.1002/ejic.201700785
European Journal of Inorganic Chemistry
For the isomer II, the minimum energy was found for conformer with the B-S-C-C angle
being equal to 58.8° in which the C≡C-SiMe3 substituent is located above the open face of
carborane cage and H(12)…C(2) close contact of 2.756 is formed (Figure 5). Energy of this
conformer is lower by 0.3 kcal/mol only than that for the optimized experimental conformer of
isomer I. This difference is comparable with the racemization activation energy [21] that can
explain the presence of different isomers in the solid state (isomer I) and in a solution (isomer
II). The isomer I, being a “longer” molecule, has relatively high dipole moment of 3.9 D that
increase energy of intermolecular interactions in the solid state, and it has more extended
molecular surface that increase the number of van der Waals intermolecular interactions.
Therefore one would expect higher stabilization (higher crystal packing energy) for isomer I,
which is formed in the solid state.
Conclusions
Simple and convenient methods of synthesis of 10-dimethylsulfonium- and 10-
methylthio-derivatives of nido-carborane, 10-Me2S-7,8-C2B9H11 and [10-MeS-7,8-C2B9H11]-,
were developed. A series of 10-alkylmethylsulfonium derivatives of nido-carborane 10-R(Me)S-
7,8-C2B9H11 (R = Et, Pr, Bu, All, Bn, CH2C≡CH, CH2C≡CPh, CH2C≡CSiMe3) were prepared by
alkylation of [10-MeS-7,8-C2B9H11]-. The 11B NMR spectra of the last three compounds
containing acetylene group demonstrate unusually strong signal splitting that can be explained
by localization of the extra-hydrogen atom over B(9)-B(10) edge due to its intramolecular B-
H…π(C≡C) interactions. The existence of these interactions is supported by X-ray crystal
structure of 10-HC≡CCH2(Me)S-7,8-C2B9H11 with shortened B-H…C contact of 2.658 Å. This
is the first example of the intramolecular B-H…π(C≡C) hydrogen bonding that expands area of
weak interactions involving B-H bonds [48], that include unconventional homopolar dihydrogen
B-H···H-B [49], hydrogen B-H···π(Ar) [50] and hydride-halogen B-H···X [20] interactions.
Experimental
Materials and Methods. (Me3NH)[7,8-C2B9H12] [51], PhC≡CCH2OH [52] and
Me3SiC≡CCH2OH [53] were prepared as described in the literature. Toluene was distilled under
sodium. All other chemicals were reagent grade and received from standard commercial vendors.
The reaction progress was monitored by TLC (Merck F254 silica gel on aluminum plates) and
visualized using 0.5% PdCl2 in 1% HCl in aq. MeOH (1:10). Acros Organics silica gel (0.060-
11
13
0.200 mm) was used for column chromatography. The 1H, 11B, B{1H}, and C NMR spectra
1
1
were recorded on Bruker Avance-400 spectrometer (SF = 400.13 MHz for H nuclei). H
11
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10.1002/ejic.201700785
European Journal of Inorganic Chemistry
chemical shifts were referenced to residual protons of the lock solvents. 11B chemical shifts were
referenced externally to BF3•OEt2. The assignment of signals in the 11B NMR spectra was
performed using 11B-11B COSY NMR with consideration of the "hydrogen bridge" rule [29]. The
electron ionization mass spectra were obtained with a Kratos MS 890 instrument, the high
resonation mass spectra — with a Bruker Daltonics microOTOF II instrument.
Synthesis of C6H5C≡CCH2OSO2CH3. To solution of C6H5C≡CCH2OH (0.99 g, 7.50
mmol) in CH2Cl2 (10 ml) at 0 °C Et3N (4.2 ml, 3.04 g, 30.00 mmol) and MsCl (2.3 ml, 3.44 g,
30.00 mmol) were added. The reaction mixture was allowed to warm to RT overnight. The
solution was washed by water (3x20 ml), then the organic fraction was separated, dried over
Na2SO4 and evaporated under reduced pressure to give 1.06 g (67%) of brown oil
1
C6H5C≡CCH2OSO2CH3. H NMR (СDCl3, ppm): 7.45 (2H, m, ArH(meta-)), 7.35 (3H, m,
ArH(ortho-+para-)), 4.48 (2H, s, СН2O), 3.67 (3H, s, CH3SO2).
Synthesis of Me3SiC≡CCH2OSO2CH3. Solution of Me3SiC≡CCH2OH (0.64 g, 5.00
mmol) in CH2Cl2 (10 ml) was cooled to 0 °C on ice bath, than Et3N (2.1 ml, 1.52 g, 15.00 mmol)
and MsCl (1.2 ml, 1.72 g, 15.00 mmol) were added. Mixture was allowed to warm to RT
overnight. The solution was washed by H2O (3x20 ml), than organic fraction was separated,
dried over Na2SO4 and then evaporated under reduced pressure to give 0.75 g 73%) of brown oil
1
Me3SiC≡CCH2OSO2CH3. H NMR (СDCl3, ppm): 4.13 (2H, s, СН2O), 3.68 (3H, s, CH3SO2),
0.18 (9H, s, (CH3)3Si).
Synthesis of 10-Me2S-7,8-C2B9H11 (1). Suspension of (Me3NH)[7,8-C2B9H12] (2.85 g,
14.85 mmol) and 5 ml H2SO4 in toluene (25 ml) was stirred until all nido-carborane was
dissolved. The organic layer was separated and Me2S (2.22 ml, 1.86 g, 30.00 mmol) and toluene
(10 ml) were added. The solution turned yellow and was heated under reflux for 8 h. Then the
solution was cooled to room temperature and evaporated in vacuo. The residue was dried under
1
reduced pressure to give 2.20 g (76%) of yellow oily product 10-Me2S-7,8-C2B9H11 (2). H
NMR (acetone-d6, ppm): 2.72 (6H, s, СН3S), 2.19 (2H, br s, СНcarb), 2.7 — 0.2 (8Н, br m, ВН),
11
–1.06 (1Н, br q, J = 50 Hz, Н-B(10)). B NMR (acetone-d6, ppm): –11.3 (2В, d, J = 142 Hz,
B(9,11)), –15.9 (2В, d, J = 146 Hz, B(5,6)), –17.4 (1В, d, J = 165 Hz, B(3)), –21.0 (2В, d, J =
153 Hz, B(2,4)), –25.8 (1В, d, J = 47 Hz, B(10)-S), –37.4 (1В, d, J = 144 Hz, B(1)).
Synthesis of (Bu4N)[10-MeS-7,8-C2B9H11] (2). Suspension of 1 (2.14 g, 11.00 mmol)
and NaNH2 (4.29 g, 110.00 mmol) in toluene (100 ml) was heated under reflux for 8 h under
argon. A precipitate was formed. Then the reaction mixture was slowly quenched by water (50
ml). The aqueous layer was separated; organic layer was washed by water (50 ml). The product
was precipitated from combined aqueous fraction with solution of Bu4NBr (5.32 g, 16.50 mmol)
in water (15 ml). The white precipitate was filtered and dried under P2O5 to give 3.95 g (85%) of
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1
(Bu4N)[10-MeS-7,8-C2B9H11] (3). H NMR (СDCl3, ppm): 3.22 (8H, t, Bu4N+), 2.07 (3H, s,
СН3S), 1.92 (2H, br s, СНcarb), 1.65 (8H, m, Bu4N+), 1.47 (8H, m, Bu4N+), 1.04 (12H, t, Bu4N+),
2.7 — 0.0 (8Н, br m, ВН), –1.24 (1Н, br q, J = 59 Hz, Н-B(10)). 11B NMR (CDCl3, ppm): –11.1
(2В, d, J = 134 Hz, B(9,11)), –15.0 (2В, d, J = 132 Hz, B(5,6)), –20.3 (1В, d, J = 151 Hz, B(3)),
–21.2 (1В, d, J = 61 Hz, B(10)-S), –22.1 (2В, d, J = 146 Hz, B(2,4)), –38.4 (1В, d, J = 134 Hz,
13
B(1)). C NMR (СDCl3, ppm): 59.0 (Bu4N+), 42.3 (Сcarb), 26.1 (Bu4N+), 19.7 (Bu4N+), 16.3
(CH3S), 13.7 (Bu4N+). HRMS (ESI): m/z for C4H17B9S: calcd 179.1728, obsd 179.1728 [M]–.
Synthesis of 10-Et(Me)S-7,8-C2B9H11 (3). Solution of 2 (0.42 g, 1.00 mmol) and EtI
(120 l, 0.23 g, 1.50 mmol) in CHCl3 (25 ml) was heated under reflux for 24 h. Then the
reaction mixture was cooled to room temperature and solvent was removed under reduced
pressure. The crude product was purified by column chromatography on silica using CHCl3 as
1
eluent to give 0.16 g (74%) of white oily solid 10-Et(Me)S-7,8-C2B9H11 (3). H NMR (СDCl3,
ppm): 3.11 (1H, dq, J2 = 12 Hz, J3 = 8 Hz, СНHS), 2.86 (1H, dq, J2 = 12 Hz, J3 = 8 Hz, СНHS),
2.49 (3H, s, СН3S), 2.23 (2H, br s, СНcarb), 1.49 (3H, t, J3 = 8 Hz, CH3СН2S), 2.9 — 0.3 (8Н, br
11
m, ВН), –1.22 (1Н, br q, J = 48 Hz, Н-B(10)). B NMR (СDCl3, ppm): –11.5 (2В, d, J = 139
Hz, B(9,11)), –15.8 (1В, d, B(5/6)), –16.1 (1В, d, B(5/6)), –16.8 (1В, d, J = 175 Hz, B(3)), –20.4
(2В, d, J = 151 Hz, B(2,4)), –26.6 (1В, d, J = 53 Hz, B(10)-S), –37.2 (1В, d, J = 144 Hz, B(1)).
13C NMR (СDCl3, ppm): 46.1 (Сcarb), 37.3 (CH3CH2S), 22.8 (SCH3), 11.2 (CH3CH2S). MS (EI):
m/z for C5H19B9S: calcd 208, obsd 208 [M]+. Anal. Calcd for C5H19B9S: C, 28.80; H, 9.18; B,
46.65. Found: C, 28.32; H, 9.24; B, 46.72.
Synthesis of 10-Pr(Me)S-7,8-C2B9H11 (4). Solution of 2 (0.59 g, 1.40 mmol) and PrI
(205 l, 0.36 g, 2.10 mmol) in CHCl3 (20 ml) was heated under reflux for 24 h. Then the
reaction mixture was cooled to room temperature and solvent was removed under reduced
pressure. The crude product was purified by column chromatography on silica using CHCl3 as
1
eluent to give 0.10 g (41%) of white oily solid 10-Pr(Me)S-7,8-C2B9H11 (4). H NMR (СDCl3,
ppm): 3.04 (1H, dt, J2 = 12 Hz, J3 = 8 Hz, СНHS), 2.79 (1H, dt, J2 = 12 Hz, J3 = 8 Hz, СНHS),
2.48 (3H, s, СН3S), 2.23 (2H, br s, СНcarb), 1.85 (2H, tt, J3(1) = 8 Hz, J3(2) = 8 Hz,
CH3СН2CH2S), 1.11 (3H, t, J3 = 8 Hz, CH3СН2CH2S), 2.9 — 0.3 (8Н, br m, ВН), –1.23 (1Н, br
q, Н-B(10)). 11B NMR (СDCl3, ppm): –11.5 (2В, d, J = 127 Hz, B(9,11)), –15.6 (1В, d, J = 151
Hz, B(5/6)), –16.4 (1В, d, B(5/6)), –16.8 (1В, d, J = 177 Hz, B(3)), –20.3 (1В, d, J = 160 Hz,
B(2/4)), –20.5 (1В, d, J = 144 Hz, B(2/4)), –26.4 (1В, d, B(10)-S), –37.2 (1В, d, J = 139 Hz,
B(1)). 46.1 (Сcarb), 44.8 (CH3CH2CH2S), 23.2 (SCH3), 19.5 (CH3CH2CH2S), 12.9
(CH3CH2CH2S). MS (EI): m/z for C6H21B9S: calcd 222, obsd 222 [M]+. Anal. Calcd for
C5H21B9S: C, 32.38; H, 9.51; B, 43.71. Found: C, 32.12; H, 9.44; B, 43.67.
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Synthesis of 10-Bu(Me)S-7,8-C2B9H11 (5). Solution of 3 (0.42 g, 1.00 mmol) and BuBr
(161 l, 0.21 g, 1.50 mmol) in CHCl3 (25 ml) was heated under reflux for 24 h. Then the
reaction mixture was cooled to room temperature and solvent was removed under reduced
pressure. The crude product was purified by column chromatography on silica using CHCl3 as
1
eluent to give 0.10 g (41%) of white oily solid 10-CH3CH2CH2CH2(Me)S-7,8-C2B9H11 (6). H
NMR (СDCl3, ppm): 3.05 (1H, dt, J2 = 12 Hz, J3 = 8 Hz, СНHS), 2.80 (1H, dt, J2 = 12 Hz, J3 = 8
Hz, СНHS), 2.49 (3H, s, СН3S), 2.22 (2H, br s, СНcarb), 1.78 (2H, tt, J3(1) = 8 Hz, J3(2) = 8 Hz,
CH3CH2СН2CH2S), 1.50 (2H, dq, J3= 8 Hz, CH3СН2CH2CH2S), 1.11 (3H, t, J3 = 8 Hz,
11
CH3СН2CH2CH2S), 2.9 — 0.3 (8Н, br m, ВН), –1.23 (1Н, br q, Н-B(10)). B NMR (СDCl3,
ppm): –11.5 (2В, d, J = 140 Hz, B(9,11)), –15.6 (2В, d, J = 138 Hz, B(5/6)), –16.3 (1В, d,
B(5/6)), –16.9 (1В, d, J = 166 Hz, B(3)), –20.6 (2В, d, J = 136 Hz, B(2, 4)), –26.5 (1В, d, B(10)-
S), –37.3 (1В, d, J = 143 Hz, B(1)). 13C NMR (СDCl3, ppm): 46.0 (Сcarb), 42.8
(CH3CH2CH2CH2S), 27.8 (CH3CH2CH2CH2S), 23.3 (SCH3), 21.6 (CH3CH2CH2CH2S), 13.4
(CH3CH2CH2CH2S). MS (EI): m/z for C7H23B9S: calcd 237, obsd 237 [M]+. Anal. Calcd for
C5H23B9S: C, 35.53; H, 9.80; B, 41.12. Found: C, 35.31; H, 9.57; B, 41.03.
Synthesis of 10-H2C=CHCH2(Me)S-7,8-C2B9H11 (6). Solution of 2 (0.59 g, 1.40 mmol)
and allyl chloride (171 l, 0.16 g, 2.10 mmol) in CHCl3 (20 ml) was heated under reflux for 24
h. Then the reaction mixture was cooled to room temperature and solvent was removed under
reduced pressure. The crude product was purified by column chromatography on silica using
CHCl3 as eluent to give 0.21 g (67%) of white oily solid 10-H2C=CHCH2(Me)S-7,8-C2B9H11
1
(6). H NMR (СDCl3, ppm): 5.89 (1H, m, H2C=СНCH2S), 5.56 (1H, d, J3= 12 Hz,
HHC=СНCH2S), 5.50 (1H, d, J3= 16 Hz, HHC=СНCH2S), 3.75 (1H, dd, J2 = 14 Hz, J3 = 6 Hz,
H2C=CHСНHS), 3.45 (1H, dd, J2 = 14 Hz, J3 = 8 Hz, H2C=CHСНHS), 2.44 (3H, s, СН3S), 2.24
11
(2H, br s, СНcarb), 2.9 — 0.3 (8Н, br m, ВН), –1.20 (1Н, br q, Н-B(10)). B NMR (СDCl3,
ppm): –11.5 (2В, d, J = 139 Hz, B(9,11)), –15.6 (1В, d, J = 137 Hz, B(5/6)), –16.3 (1В, d,
B(5/6)), –16.9 (1В, d, J = 170 Hz, B(3)), –20.5 (2В, d, J = 134 Hz, B(2,4)), –26.6 (1В, d, B(10)-
13
S), –37.2 (1В, d, J = 144 Hz, B(1)). C NMR (СDCl3, ppm): 126.4 (H2C=СНCH2S), 125.6
(H2C=СНCH2S), 46.4 (Сcarb), 45.5 (H2C=СНCH2S), 22.0 (SCH3). MS (EI): m/z for C6H19B9S:
calcd 220, obsd 220 [M]+. Anal. Calcd for C6H19B9S: C, 32.67; H, 8.68; B, 44.11. Found: C,
32.44; H, 8.63; B, 44.19.
Synthesis of 10-C6H5CH2(Me)S-7,8-C2B9H11 (7). Solution of 2 (0.59 g, 1.40 mmol) and
benzyl bromide (242 l, 0.27 g, 2.10 mmol) in CHCl3 (20 ml) was heated under reflux for 24 h.
Then the reaction mixture was cooled to room temperature and solvent was removed under
reduced pressure. The crude product was purified by column chromatography on silica using
CHCl3 as eluent to give 0.28 g (73%) of white crystalline solid 10-C6H5CH2(Me)S-7,8-C2B9H11
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1
(7). H NMR (СDCl3, ppm): 7.43 (3H, m, ArH (ortho+para), 7.33 (2H, m, ArH (meta)), 4.40
(1H, d, J2 = 13 Hz, СНHS), 3.88 (1H, d, J2 = 13 Hz, СНHS), 2.31 (3H, s, СН3S), 2.26 (2H, br s,
11
СНcarb), 2.9 — 0.3 (8Н, br m, ВН), –1.15 (1Н, br q, Н-B(10)). B NMR (СDCl3, ppm): –11.6
(2В, d, J = 138 Hz, B(9,11)), –15.9 (2В, d, J = 146 Hz, B(5,6)), –16.8 (1В, d, J = 170 Hz, B(3)),
13
–20.3 (2В, d, J = 158 Hz, B(2,4)), –26.5 (1В, d, B(10)-S), –37.1 (1В, d, J = 146 Hz, B(1)). C
NMR (СDCl3, ppm): 129.78 (CAr), 129.77 (CAr), 129.7 (CAr), 129.6 (CAr), 47.6 (PhCH2S), 46.2
(Сcarb), 22.1 (SCH3). MS (EI): m/z for C10H21B9S: calcd 270, obsd 270 [M]+. Anal. Calcd for
C10H21B9S: C, 44.38; H, 7.82; B, 35.95. Found: C, 44.19; H, 7.75; B, 36.02.
Synthesis of 10-HC≡CCH2(Me)S-7,8-C2B9H11 (8). Mixture of 2 (0.59 g, 1.40 mmol)
and 80 wt.% solution of propargyl bromide in toluene (234 l, 0.25 g, 2.10 mmol) in CHCl3 (20
ml) was heated under reflux for 24 h. Then the reaction mixture was cooled to room temperature
and solvent was removed under reduced pressure. The crude product was purified by column
chromatography on silica using CHCl3 as eluent to give 0.22 g (72%) of white crystalline solid
1
10-HC≡CCH2(Me)S-7,8-C2B9H11 (8). H NMR (СDCl3, ppm): 3.80 (1H, dd, J2 = 16 Hz, J4 = 2
Hz, СНHS), 3.68 (1H, dd, J2 = 16 Hz, J4 = 2 Hz, СНHS), 2.65 (3H, s, СН3S), 2.62 (1H, t, J4 = 2
Hz, HC≡СCH2S), 2.25 (2H, br s, СНcarb), 2.9 — 0.3 (8Н, br m, ВН), –1.10 (1Н, br q, Н-B(10)).
11B NMR (СDCl3, ppm): –11.3 (1В, d, J = 137 Hz, B(11)), –12.0 (1В, d, J = 146 Hz, B(9)), –
14.7 (1В, d, J = 144 Hz, B(6)), –16.8 (2В, d, J = 149 Hz, B(5)+B(3)), –19.8 (1В, d, J = 156 Hz,
B(4)), –20.5 (1В, d, J = 156 Hz, B(2)), –26.9 (1В, d, B(10)-S), –37.1 (1В, d, J = 144 Hz, B(1)).
13C NMR (СDCl3, ppm): 77.9 (HC≡СCH2S), 72.1 (HC≡СCH2S), 47.1 (Сcarb), 45.8 (Сcarb), 31.6
(HC≡СCH2S), 22.7 (SCH3). MS (EI): m/z for C6H17B9S: calcd 218, obsd 218 [M]+. Anal. Calcd
for C6H17B9S: C, 32.97; H, 7.84; B, 44.52. Found: C, 33.05; H, 7.78; B, 44.64.
Synthesis of 10-C6H5C≡CCH2(Me)S-7,8-C2B9H11 (9). Solution of 2 (0.46 g, 1.10
mmol) and C6H5C≡CCH2OSO2CH3 (0.36 g, 1.69 mmol) in CHCl3 (20 ml) was heated under
reflux for 24 h. Then the reaction mixture was cooled to room temperature and solvent was
removed under reduced pressure. The crude product was purified by column chromatography on
silica using CHCl3 as eluent to give 0.28 g (73%) of white oily solid 10-C6H5C≡CCH2(Me)S-
1
7,8-C2B9H11 (9). H NMR (СDCl3, ppm): 7.49 (2H, m, ArH(meta-)), 7.39 (3H, m, ArH(ortho-
+para-)), 4.06 (1H, d, J2 = 16 Hz, СНHS), 3.95 (1H, d, J2 = 16 Hz, СНHS), 2.68 (3H, s, СН3S),
1
2.27 (2H, br s, СНcarb), 2.9 — 0.3 (8Н, br m, ВН), –1.00 (1Н, br q, Н-B(10)). H NMR (С6D6,
ppm): 7.34 (2H, m, ArH(meta-)), 7.66 (3H, m, ArH(ortho-+para-)), 2.88 (1H, d, J2 = 16 Hz,
СНHS), 2.78 (1H, d, J2 = 16 Hz, СНHS), 2.26 (2H, br s, СНcarb), 1.47 (3H, s, СН3S), 3.4 — 0.3
11
(8Н, br m, ВН), –1.14 (1Н, br q, Н-B(10)). B NMR (СDCl3, ppm): –11.1 (1В, d, J = 142 Hz,
B(11)), –12.2 (1В, d, J = 146 Hz, B(9)), –14.2 (1В, d, J = 144 Hz, B(6)), –17.8 (2В, d, J = 134
Hz, B(5)+B(3)), –19.6 (1В, d, J = 160 Hz, B(4)), –20.5 (1В, d, J = 156 Hz, B(3)), –26.8 (1В, d,
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European Journal of Inorganic Chemistry
11
B(10)-S), –37.2 (1В, d, J = 142 Hz, B(1)). B NMR (С6D6, ppm): –10.6 (1В, d, J = 123 Hz,
B(11)), –11.7 (1В, d, J = 137 Hz, B(9)), –13.6 (1В, d, J = 142 Hz, B(6)), –16.4 (2В, d, J = 139
Hz, B(5)+B(3)), –19.0 (1В, d, J = 146 Hz, B(4)), –19.8 (1В, d, J = 156 Hz, B(2)), –26.8 (1В, d,
13
B(10)-S), –36.2 (1В, d, J = 151 Hz, B(1)). C NMR (СDCl3, ppm): 132.2 (CAr(meta-)), 129.9
(CAr(para-)), 128.8 (CAr(ortho-)), 120.9 (CAr(ipso-)), 89.6 (PhC≡СCH2S), 76.8 (PhC≡СCH2S),
47.2 (Сcarb), 45.5 (Сcarb), 33.0 (HC≡СCH2S), 22.7 (SCH3). 13C NMR (С6D6, ppm): 132.1
(CAr(meta-)), 129.8 (CAr(para-)), 128.9 (CAr(ortho-)), 121.5 (CAr(ipso-)), 88.9 (PhC≡СCH2S),
77.8 (PhC≡СCH2S), 47.4 (Сcarb), 45.8 (Сcarb), 32.0 (HC≡СCH2S), 21.5 (SCH3). MS (EI): m/z for
C12H21B9S: calcd 295, obsd 295 [M]+. Anal. Calcd for C12H21B9S: C, 48.92; H, 7.18; B, 33.02.
Found: C, 48.67; H, 7.13; B, 32.98.
Synthesis of 10-Me3SiC≡CCH2(Me)S-7,8-C2B9H11 (10). Solution of 2 (0.46 g, 1.10
mmol) and Me3SiC≡CCH2OSO2CH3 (0.37 g, 1.81 mmol) in CHCl3 (20 ml) was heated under
reflux for 24 h. Then the reaction mixture was cooled to room temperature and solvent was
removed under reduced pressure. The crude product was purified by column chromatography on
silica using CHCl3 as eluent to give 0.28 g (73%) of white crystalline solid
1
Me3SiC≡CCH2(Me)S-7,8-C2B9H11 (10). H NMR (СDCl3, ppm): 3.79 (1H, d, J = 16 Hz,
СНHS), 3.73 (1H, d, J = 16 Hz, СНHS), 2.60 (3H, s, СН3S), 2.25 (1H, br s, СНcarb), 2.22 (1H, br
11
s, СНcarb), 2.9 — 0.3 (8Н, br m, ВН), 0.23 (9H, s, (CH3)3Si), –1.10 (1Н, br q, Н-B(10)). B
NMR (СDCl3, ppm): –11.0 (1В, d, J = 132 Hz, B(11)), –12.6 (1В, d, J = 122 Hz, B(9)), –13.5
(1В, d, J = 132 Hz, B(6)), –16.8 (1В, d, J = 165 Hz, B(3)), –17.9 (1В, d, J = 137 Hz, B(5)), –19.4
(1В, d, J = 184 Hz, B(4)), –20.8 (1В, d, J = 146 Hz, B(2)), –27.0 (1В, d, B(10)-S), –37.2 (1В, d,
13
J = 139 Hz, B(1)). C NMR (СDCl3, ppm): 96.6 (Me3SiC≡СCH2S), 92.4 (Me3SiC≡СCH2S),
47.6 (Сcarb), 45.1 (Сcarb), 32.7 (Me3SiC≡СCH2S), 22.3 (SCH3), –0.3 ((CH3)3Si). MS (EI): m/z for
C9H25B9SSi: calcd 291, obsd 291 [M]+. Anal. Calcd for C9H25B9SSi: C, 37.18; H, 8.67; B, 33.46.
Found: C, 36.93; H, 8.52; B, 33.52.
Single Crystal X-Ray Diffraction Study.
Single crystal X-ray study was carried out with SMART APEX II CCD diffractometer
(λ(Mo-Kα)=0.71073 A, graphite monochromator, ω-scans) at 120 K. The structures were solved
by the direct methods and refined by the full-matrix least-squares procedure in anisotropic
approximation for non-hydrogen atoms.
Crystallographic data for 7: C10H21B9S are monoclinic, space group P21/n: a = 11.3567(9) Å, b
= 10.3157(8) Å, c = 13.7991(10) Å,  =104.885(2)°, V = 1562.3(2) Å3, Z = 4, M = 270.62, dcalc
= 1.151 gcm-3. wR2 = 0.1328 calculated on F2 for all 3045 independent reflections with 2 <
hkl
52.0, (GOF = 1.035 R = 0.0496 calculated on Fhkl for 2042 reflections with I > 2(I)).
Crystallographic data (excluding structure factors) for the structure have been deposited at the
16
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10.1002/ejic.201700785
European Journal of Inorganic Chemistry
Cambridge Crystallographic Data Centre (CCDC) as supplementary publication No. CCDC
1550065.
Crystallographic data for 8: C6H17B9S, monoclinic, space group P21/n: a = 8.8664(14) Å, b =
10.983(2) Å, c = 13.697(2) Å,  = 108.705(4)°, V = 1263.3(3) Å3, Z = 4, M = 218.55, dcalc
=
1.149 gcm-3, wR2 = 0.1165 calculated on F2 for all 2804 independent reflections with 2 <
hkl
54.34, (GOF = 0.996 R = 0.0481 calculated on Fhkl for 1862 reflections with I > 2(I)).
Crystallographic data (excluding structure factors) for the structure have been deposited at the
Cambridge Crystallographic Data Centre (CCDC) as supplementary publication No. CCDC
1550066.
Crystallographic data for 10: C9H25B9SSi, monoclinic, space group P21/c: a = 13.208(3) Å, b =
10.911(3) Å, c = 12.102(3) Å,  = 90.134(5)°, V = 1744.1(7) Å3, Z = 4, M = 290.73, dcalc = 1.107
gcm-3, wR2 = 0.1363 calculated on F2 for all 3723 independent reflections with 2 < 54.0,
hkl
(GOF = 1.019 R = 0.0489 calculated on Fhkl for 2567 reflections with I > 2(I)).
Crystallographic data (excluding structure factors) for the structure have been deposited at the
Cambridge Crystallographic Data Centre (CCDC) as supplementary publication No. CCDC
1550067.
Acknowledgment
This work was supported by the Russian Science Foundation (16-13-10331). The NMR
and X-ray diffraction data were obtained using the equipment of Center for Molecular Structure
Studies at A.N.Nesmeyanov Institute of Organoelement Compounds.
Supplementary material
Electronic Supplementary Information (ESI) contains NMR spectra of compounds 1-10, X-
ray structures of compounds 7, 8 and 10 (CCDC 1550065, 1550066 and 1550067, respectively).
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