Structure of hypercoordinated monoorganodihalostannanes in solutions and in the solid state: The halogen effect

Article abstract of DOI:10.1016/j.ica.2015.04.006

A series of hypercoordinated monoorganotin dibromides formed by glycolic acid amides, [RSnBr₂(OCH₂C(O)NR′₂)]₂ (2a, R = Et, NR′₂ = NMe₂; 3a, R = n-Bu, NR′₂ = NMe₂; 4b,

Full text of DOI:10.1016/j.ica.2015.04.006

Inorganica Chimica Acta 432 (2015) 142–148
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Inorganica Chimica Acta
journal homepage: www.elsevier.com/locate/ica
Structure of hypercoordinated monoorganodihalostannanes in solutions
and in the solid state: the halogen effect
David V. Airapetyan a, Valerii S. Petrosyan a, Sergey V. Gruener a, Alexander A. Korlyukov b,c
,
Dmitry E. Arkhipov b,c, Allen A. Bowden d, Kirill V. Zaitsev a,
⇑
a Department of Chemistry, M. V. Lomonosov Moscow State University, Leninskie Gory, 1, 3, 119991 Moscow, Russia
b A.N. Nesmeyanov Institute of Organoelement Compounds, RAS, Vavilova str. 28, 119991 Moscow, Russia
c N.I. Pirogov Russian National Research Medical University, Ostrovitianov str. 1, 117997 Moscow, Russia
d Department of Chemistry, University of Birmingham, Birmingham, UK
a r t i c l e i n f o
a b s t r a c t
Article history:
A
series of hypercoordinated monoorganotin dibromides formed by glycolic acid amides,
[RSnBr2(OCH2C(O)NR02)]2 (2a, R = Et, NR02 = NMe2; 3a, R = n-Bu, NR02 = NMe2; 4b, R = Ph,
NR02 = morpholin-4-yl), were obtained and investigated by X-ray analysis, multinuclear NMR spec-
troscopy in solutions (1H, 13C, 119Sn) and solid state (CP/MAS). It has been established that 2a, 3a and
4b in solid state are dimeric. For the solutions in coordinating solvents the slow monomer–dimer
equilibrium has been observed. The structures of related solvated monomeric chlorides,
RSnCl(DMSO)(OCH2C(O)NR02), 5aꢀDMSO and 6aꢀDMSO, were also investigated by X-ray analysis.
Ó 2015 Elsevier B.V. All rights reserved.
Received 8 December 2014
Received in revised form 18 March 2015
Accepted 11 April 2015
Available online 18 April 2015
Keywords:
Hypervalent compounds
Tin
Monoorganostannanes
119Sn NMR spectroscopy
X-ray diffraction
1. Introduction
(b-carboalkoxyethyltins) compounds [12], stannatranes [13], stan-
nocanes [14] and related compounds [15].
Organic compounds of tin attract nowadays significant
attention. There are several main subjects in organotin chemistry:
the investigation of compounds with multiple bonds of Sn with
elements [1], hypercoordinated derivatives and synthesis of low
valent Sn(II) compounds [2]. Organotin compounds have
applications in fine organic synthesis (e.g. reagents for Stille
cross-coupling [3]) and in industry (catalysts for ROP [4]). They
are being studied as potential pharmaceuticals (particularly due
to the toxicities of polyorganotin compounds) [5], as the precursors
for new materials [6] and as PVC stabilizers [7]. Substantial under-
standing of the chemistry of organotins comes from the studies of
the complexes with an extended coordination sphere [8]. Interest
in these derivatives includes also investigation of new structural
features and dynamic behavior [9] or possible application of
hypercoordinated Sn compounds as precursors for new unusual
chemical reactions [10]. Whereas tri- and diorganotin(IV)
complexes remain the most investigated among the series of
hypercoordinated tin, monoorganotin(IV) complexes are very
rare and have been studied mostly with monodentate electrondo-
nating ligands [11]. Notable exceptions include ‘‘estertin’’
The interaction of monoorganotin trichlorides (RSnCl3) with
O-TMS 2derivatives of -hydroxyamides resulting in the substitu-
a
tion of one chlorine atom with hydroxyamide residue has been
studied previously in our research group [16]. In continuation of
these studies we report here the detailed investigation concerning
hypercoordinated monoorganotin bromides. It should be noted
that the bromine containing organotin compounds (with only
one organic substituent) are very rare [17] and studies of these
compounds in comparison with related chlorides are rather diffi-
cult. A number of corresponding hypercoordinated compounds,
2a, 3a, 4b were obtained by interactions of monoorganotin tribro-
mides (RSnBr3) with O-TMS derivatives of amides of glycolic acid
(1a–b). The structures of these compounds in solutions and in solid
state have been studied. The structures of the related chloride
adducts with DMSO, 5a⁄DMSO, 6a⁄DMSO and 7b⁄DMSO were also
studied in solid state and in solutions.
2. Results and discussion
2.1. Synthesis
⇑
To synthesize the desired compounds well proven earlier
reaction for obtaining analogous chlorides was employed. The
Corresponding author. Tel.: +7 (495)939 38 87.
E-mail address: zaitsev@org.chem.msu.ru (K.V. Zaitsev).
http://dx.doi.org/10.1016/j.ica.2015.04.006
0020-1693/Ó 2015 Elsevier B.V. All rights reserved.

D.V. Airapetyan et al. / Inorganica Chimica Acta 432 (2015) 142–148
143
NR'2
O
advantage of this methodology is simplicity of procedure and ease
S
of isolation of target compounds. As a result of interaction of
monoorganotin tribromides (RSnBr3; R = Et, n-Bu, Ph) with
O-TMS derivatives of N,N-disubstituted amides of glycolic acid
(1a–b) the products of substitution of one halogen atom with the
glycolic amide residue were isolated in moderate yields
(Scheme 1). Compounds 2a, 3a and 4b are new. It should be noted
that reaction of 1a with PhSnBr3 and 1b with EtSnBr3 or n-BuSnBr3
resulted in complex mixtures of tin compounds from which it was
impossible to isolate the pure substances. Attempts to obtain
analogous compounds interacting monoorganotin tribromides
(RSnBr3; R = Et, n-Bu) with O-TMS derivatives of amides of lactic
and mandelic acids were unsuccessful; in these cases complicated
mixtures of unidentified compounds were formed, too.
Compounds 2a, 3a and 4b were isolated as white powders
soluble in polar organic solvents (MeCN, DMSO). These substances
are sensitive to the air moisture and should be stored in the inert
atmosphere.
The structures of compounds 2a, 3a, and 4b have been studied
in solid state using X-ray analysis and 119Sn CP/MAS spectroscopy
and in solutions by multinuclear NMR spectroscopy.
O
Br
Sn
O
O
Br
R
R
Br
R
DMSO
Sn
Br
Sn
Br
Br
O
O
NR'2
O
NR'2
M
D
Scheme 2. Dimer (D) – monomer (M) equilibrium of tin complexes in DMSO
solutions.
Unfortunately, we failed to obtain for the compounds 2a, 3a and
4b from DMSO solutions crystals, suitable for X-ray analysis.
Nevertheless, the described earlier DMSO adducts of the related
chlorides 5a and 6a (Scheme 3) were studied by X-ray analysis
(see below). It is noteworthy that the monomer–dimer equilibrium
in solution is shifted toward monomer (M) in case of chlorides 5a,
6a, 7b [10]; this has been confirmed by 1H, 13C and 119Sn NMR
spectra (Scheme 4).
In 119Sn CP/MAS NMR [19] spectrum of 4b there is only one iso-
tropic signal at d = ꢁ503 ppm, whereas in DMSO solution there are
two peaks at d = ꢁ489.7 (broad) and ꢁ494.7 ppm. Chlorides 5a and
6a (Scheme 3) in the solid state gave 119Sn chemical shifts at
d = ꢁ316 and ꢁ311 ppm, respectively. For the phenyltin compound
7b the signal in 119Sn CP/MAS NMR spectrum was observed at
d = ꢁ426 ppm.
2.2. NMR spectroscopy
Whereas the structures of the compounds in solid state were
established unambiguously with X-ray analysis, it was rather
difficult to identify the nature of the species present in solutions.
In 1H NMR spectra of the compounds 2a and 3a in the DMSO-d6
solutions recorded at 25 °C the signals are broad (Fig. S1, Supporting
Information) and 13C NMR spectra were not observed at this tem-
perature. 119Sn NMR spectra showed two signals at ꢁ417.5,
ꢁ427.4 ppm and ꢁ425.7, ꢁ431.4 ppm for 2a and 3a, respectively.
At 65 °C in 1H NMR spectrum the peaks for 3a are resolved
(Fig. S1, Supporting Information), 13C NMR spectrum was recorded
and there is only one signal at ꢁ427.9 ppm for 119Sn NMR spectrum,
albeit broad (Fig. S2, Supporting Information).
We believe, that the data obtained indicate the dynamic
processes in solution for these bromides. One can assume the equi-
librium between dimer (D), which also exists in the solid state (see
below) and monomeric adduct (M) with coordinated DMSO
(Scheme 2). In both cases tin atom is hexacoordinated [18].
The chemical shifts in NMR spectra for 2a, 3a and 4b in solution
are typical for hexacoordinated tin atoms (d = (ꢁ417)–(ꢁ496)
ppm) [18,19]. The tin – proton spin–spin coupling constants
(3J119Sn–H 87–93 Hz in Sn–OCH2 fragment and 3J119Sn–H
130–132 Hz in Sn–Alk(Ar) fragment) are typical for hypercoordi-
nated tin halide compounds [10,11,16]. The tin – carbon coupling
constants are observed only in the case of 4b (see Section 3). A
small increase in values in compounds under investigation has
been observed in comparison with the fourcoordinated tin
compounds.
Of particular interest is comparison of 119Sn NMR data for bro-
mides (2–3a, 4b) and chlorides (5–6a, 7b) in solutions and solid
state (Table 1).
From Table 1 it is evident that for alkyltin derivatives 2a, 3a, 4b,
5a and 6a the signals in 119Sn NMR spectra are shifted to high field
in bromine derivatives in comparison with the corresponding chlo-
rides. On dissolving in coordinating solvents the ligand exchange is
observed for chlorides resulting in coordination of tin with the
more polarized DMSO.
We performed additional experiments for compound 3a. Firstly,
the solvent was changed from DMSO-d6 to CD3CN. The target sig-
nal has transformed into very broad signal. Secondly, the spectra
were registered in mixtures (2:1, 1:1) of polar and strongly coordi-
nating DMSO-d6 and nonpolar and noncoordinating C6D6. It was
established that addition of C6D6 results in decreasing (and full dis-
appearance) of one of the signals (Figs. S3, S4, Supporting
Information), which may be attributed to the monomer. So, the
data obtained indicate the dependence of the behavior of the tin
compounds in solutions on the solvent’s nature and confirm the
dissociation–association equilibrium between hypercoordinated
tin bromides in solutions.
Thus, in the case of chlorides the dimeric structures obtained for
the crystals are also retained in the amorphous phase. In solutions
NR'2
O
Br
Sn
O
O
R
Br
R
Sn
Br
+
RSnBr3
- Me3SiBr
Me3SiO
NR'2
Br
O
O
R'2N
2a R = Et; R' = Me (20%)
1a R' = Me
3a R = Bu; R' = Me (19%)
1b R'2 = -(CH2)2O(CH2)2-
4b R = Ph; R'2 = -(CH2)2O(CH2)2- (37%)
Scheme 1. Synthesis of bromide tin complexes 2a, 3a and 4b.

144
D.V. Airapetyan et al. / Inorganica Chimica Acta 432 (2015) 142–148
O
O
NMe2
O
NMe2
N
O
Cl
Cl
Cl
Sn
O
O
Et
Cl
Cl
Et
c-Pr
Cl
O
Ph
Cl
Cl
Ph
Sn
Sn
Cl
Sn
O
Sn
Cl
Sn
Cl
c-Pr
O
Cl
O
O
O
O
N
Me2N
Me2N
O
7b
5a
6a
Scheme 3. The structures of chlorides 5a, 6a and 7b.
NR'2
O
S
O
Cl
Sn
O
O
DMSO
Cl
R
R
Cl
R
Sn
Cl
Sn
Cl
O
Cl
O
NR'2
O
5a
6a
7b
R = Et, R' = Me
R = n-Bu, R' = Me
R = Et, R' = -(CH2)2O(CH2)2-
5a*DMSO
6a*DMSO R = n-Bu, R' = Me
7b*DMSO R = Et, R' = -(CH2)2O(CH2)2-
R = Et, R' = Me
NR'2
Scheme 4. Solvolysis of tin chlorides 5a, 6a and 7b in DMSO solutions.
in coordinating solvents (such as DMSO), these dimers are solvated
by the solvent, resulting in a monomer structure. Structures of sev-
eral solvates were investigated by XRD (see below). The corre-
sponding bromides in the crystal and in the amorphous phase
are dimeric, too. However, unlike chlorides, for the bromides in
coordinating solvents a monomer–dimer equilibrium is observed.
2.3. X-ray analysis
Fig. 1. The molecular structure of 2a; only one independent molecule is presented;
hydrogen atoms are omitted for clarity. Displacement ellipsoids are shown at 50%
probability level.
The molecular structures of five compounds obtained in the
course of this work were investigated by X-ray analysis (Figs. 1–5,
Tables 2–4).
The structural parameters of the three molecules under investi-
gation are very similar. Furthermore, there are very small bond
elongations in Br derivatives in comparison with corresponding
Cl compounds [16] (compare, for example, average values for 2a/
5a: Sn–O1 2.199(2)/2.193(1), Sn–O2 2.088(2)/2.086(1), Sn–O2A
2.273(2)/2.265(1), Sn–C 2.143(3)/2.135(1) Å). This gives the possi-
bility to propose that in crystals the hypercoordinated tin atoms
exhibit similar Lewis acidity both in cases of chlorides and
bromides.
Structures 2a, 3a and 4b are the first compounds containing
O3Sn(C)Br2 fragment which were investigated by X-ray analysis.
The compounds 2a and 3a are isostructural and similar to 5a
[16]; there are two independent molecules in crystal of 2a.
The bromides 2a, 3a, 4b in the solid state are centrosymmetric
dimers due to the coordination bond between tin and the oxygen
atom of glyoxylic fragment from another molecule. So, in these
cases a ladder type fragments are formed consisting of three cycles
with almost planar Sn2O2. Tin atom is hexacoordinated and bro-
mine atoms (in cis-positions) situated trans to oxygens which form
coordination bonds with tin atoms.
The molecular structures of monomeric chlorides 5a⁄DMSO and
6a⁄DMSO are isostructural. DMSO is coordinated via O to tin which
Table 1
119Sn NMR data for 2a, 3a, 4b, 5a, 6a and 7b in DMSO-d6 solutions and solid state.
Compound
DMSO-d6 solutions
119Sn ppma
Solid state
d
Monomer (M)/dimer (D)b
d
119Sn ppma
Monomer (M)/dimer (D)b
2a
3a
4b
5a
6a
7b
ꢁ427; ꢁ417
ꢁ426; ꢁ431
ꢁ489(br.); ꢁ495
ꢁ376
Equilibrium (M)/(D)
Equilibrium (M)/(D)
Equilibrium (M)/(D)
(M)
(M)
(M)
–
–
–
–
(D)
(D)
(D)
(D)
ꢁ503
ꢁ316
ꢁ311
ꢁ426
ꢁ377
ꢁ437
a
The spectra were registered at 298 °K.
M – monomer with coordinated DMSO; D – dimer (see Scheme 2).
b

D.V. Airapetyan et al. / Inorganica Chimica Acta 432 (2015) 142–148
145
Fig. 2. The molecular structure of 3a; hydrogen atoms are omitted for clarity.
Displacement ellipsoids are shown at 50% probability level.
Fig. 5. The molecular structure of 6aꢀDMSO; hydrogen atoms are omitted for
clarity. Displacement ellipsoids are shown at 50% probability level.
in trans-positions to oxygen atoms which are coordinated to Sn.
It should be noted that the tin compounds containing cyclopropyl
group have been almost unknown to date, in fact there were only
two structures of tetracoordinated Sn derivatives [21].
In general, the bond lengths in 6a⁄DMSO are somewhat shorter
than in 5a⁄DMSO likely due to presence of the cyclopropyl group.
The main feature of 5a⁄DMSO are almost equal Sn–O bond lengths
with coordinative O atoms from DMSO and glycolic fragment
(2.2101(10) versus 2.2127(10) Å). Furthermore, the similar bond
lengths in 5a⁄DMSO are somewhat longer than the related ones
in dimer 5a [16] (compare, for example, Sn–C 2.1364(14)/
2.1351(14), Sn–Cl1 2.4550(3)/2.4190(4), Sn–O2 2.2127(10)/
2.1928(10) Å) this may be explained by the fact that DMSO mole-
cule is a better donor for Sn than oxygen atom from another com-
plex molecule in the chlorine derivatives.
Moreover, it should be noted that the significant trans-effect in
5a⁄DMSO and 6a⁄DMSO is observed. The elongation of Sn–Cl2
bond lengths (trans- to DMSO) in comparison with Sn–Cl1 indi-
cates more significant donor properties of DMSO in comparison
with the coordinative C(O)NMe2 group.
Fig. 3. The molecular structure of 4b; hydrogen atoms are omitted for clarity.
Displacement ellipsoids are shown at 50% probability level.
The Sn–O bond lengths in 5a⁄DMSO and 6a⁄DMSO are elon-
gated in comparison with free DMSO (1.5456(10) and 1.5478(11)
versus 1.531(5) Å [22]), reflecting a significant polarized structure
in coordinating DMSO molecule for these chlorides.
Due to absence of OH and NH groups the crystal packing of
structures studied are constructed via weak C–Hꢀ ꢀ ꢀO and C–
Hꢀ ꢀ ꢀBr bonds. All intermolecular distances correspond to ordinary
van-der-Waals interactions.
3. Experimental
3.1. General
All solvents were purified using standard procedures (hexane
and C6D6 were refluxed over Na; diethyl ether was stored over
KOH, refluxed over Na/benzophenone; MeCN was refluxed over
CaH2; DMSO-d6 was refluxed over CaH2 and after distillation in
vacuum is stored over molecular sieves) and redistilled prior to
use. Syntheses of the compounds 2a, 3a and 4b were carried out
in the argon atmosphere using standard Schlenk technique.
The IR spectra were recorded by using a 200 Thermo Nicolet
apparatus. 1H, 13C and 119Sn NMR spectra for solutions were
Fig. 4. The molecular structure of 5aꢀDMSO; hydrogen atoms are omitted for
clarity. Displacement ellipsoids are shown at 50% probability level.
is typical for Sn compounds [20]. In both compounds tin atom has a
distorted octahedral environment in which oxygen atoms occupy
cis-positions (fac-configuration). The chlorine atoms are situated
recorded by using
a Bruker Avance 400 NMR spectrometer
(400.1, 100.6 and 106.2 MHz, respectively). The chemical shifts

146
D.V. Airapetyan et al. / Inorganica Chimica Acta 432 (2015) 142–148
Table 2
Principal bond lengths (Å) and angles (°) for compounds 2a, 3a and 4b.
2aa
3a
4b
Sn1–Br1 2.5869(4)
Sn1–Br2 2.5805(4)
Sn1–O1 2.190(2)
Sn2–Br3 2.5656(4)
Sn2–Br4 2.5931(4)
Sn2–O3 2.207(2)
Sn1–Br1 2.5709(7)
Sn1–Br2 2.5762(7)
Sn1–O1 2.200(2)
Sn1–Br1 2.5594(9)
Sn1–Br2 2.5610(9)
Sn1–O1 2.204(5)
Sn1–O2 2.087(2)
Sn2–O4 2.089(2)
Sn1–O2 2.069(2)
Sn1–O2 2.073(5)
Sn1–O2A 2.276(2)
Sn1–C5 2.147(3)
Sn2–O4A 2.269(2)
Sn2–C11 2.138(3)
Sn1–O2A 2.305(2)
Sn1–C5 2.123(3)
Sn1–O2A 2.285(5)
Sn1–C7 2.140(7)
O2–Sn1–C5 154.51(11)
O2–Sn1–Br1 165.42(5)
O1–Sn1–Br2 166.42(6)
Sn1–O2–Sn1 108.42(9)
O2–Sn1–O2 71.58(9)
O4–Sn2–C11 155.65(11)
O3–Sn2–Br3 167.18(6)
O4–Sn2–Br4 163.81(6)
Sn2–O4–Sn2 108.85(9)
O4–Sn2–O4 71.15(9)
O2–Sn1–C5 151.27(12)
O1–Sn1–Br1 167.01(7)
O2A–Sn1–Br2 164.98(6)
Sn1–O2–Sn1A 108.82(10)
O2–Sn1–O2A 71.18(10)
O2–Sn1–C7 154.2(2)
O2A–Sn1–Br(1) 166.63(12)
O1–Sn1–Br2 166.60(13)
Sn1–O2–Sn1A 107.53(19)
O2–Sn1–O2A 72.47(12)
a
Two independent molecules.
Table 3
Principal bond lengths (Å) and angles (°) for compounds 5a⁄DMSO and 6a⁄DMSO.
3.2. Synthesis
3.2.1. Phenytin tribromide (PhSnBr3)
5a⁄DMSO
6a⁄DMSO
The mixture of Ph4Sn (1.68 g, 3.90 mmol) and SnBr4 (5.12 g,
12.00 mmol) were stirred under argon at 190 °C for 16 h.
Fractionation in vacuum gave 5.16 g (75%) of PhSnBr3 as a colorless
liquid, b.p. 101 °C at 0.5 mm Hg, lit. [26] b.p. 182–183 °C at 29 mm
Hg. 1H NMR (400.1 MHz, C6D6, 25 °C): d = 7.08–7.05 (m, 2H, aro-
matic hydrogens), 6.93–6.96 (m, 3H, aromatic hydrogens) ppm.
13C NMR (100.6 MHz, C6D6, 25 °C): d = 137.86, 133.30, 132.40 and
129.88 (aromatic carbons) ppm. 119Sn NMR (106.2 MHz, C6D6,
25 °C): d = ꢁ225.3 ppm.
Sn1–Cl1 2.4550(3)
Sn1–Cl2 2.4730(4)
Sn1–O1 2.0064(10)
Sn1–O2 2.2127(10)
Sn1–O3 2.2101(10)
Sn1–C1 2.1364(14)
S1–O3 1.5456(10)
O1–Sn1–C1 166.92(5)
O2–Sn1–Cl1 166.30(3)
O3–Sn1–Cl2 173.33(3)
Sn1–Cl1 2.4467(4)
Sn1–Cl2 2.4719(4)
Sn1–O2 2.0081(11)
Sn1–O1 2.1974(11)
Sn1–O1A 2.2073(11)
Sn1–C1 2.1062(15)
S1A–O1A 1.5478(11)
O2–Sn1–C1 166.00(5)
O1–Sn1–Cl1 169.48(3)
O1A–Sn1–Cl2 172.72(3)
3.2.2. Synthesis of compound 2a
were measured using tetramethylsilane (1H, 13C) or tetramethyltin
119Sn) as the internal references. The 119Sn CP/MAS NMR spectra
were recorded on a JEOL EX 400 NMR (149.1 MHz) using a
DOTY solid state probe and 5 mm rotors, at room temperature
(25 °C); contact time 5 ms; relaxation delay 5 s; number of scans
12800. The chemical shifts were externally referenced to
tetramethyltin.
O-TMS derivatives of N,N-dimethylamide (1a) [16] and mor-
pholinyl (1b) [23] of glycolic acid, EtSnBr3 [24] and n-BuSnBr3
[25], complexes 5a, 6a and 7b [10] were synthesized according
to the described procedures.
To a stirred solution of EtSnBr3 (0.97 g, 2.50 mmol) in hexane
(7 mL) the solution of compound 1a (0.44 g, 2.50 mmol) in hexane
(7 mL) was added drop wise at ambient temperature, the mixture
was stirred for 30 min at the same temperature and refluxed for
1 h. After cooling the precipitate formed was filtered off, washed
with hexane and dried in vacuum. Yield was 0.91 g of product con-
taining some impurities according to 1H NMR. Recrystallization
from acetonitrile gave 0.21 g (20%) of pure product as a white crys-
(
talline solid, m. p. 203–204 °C. IR (KBr):
1060 cmꢁ1 1H NMR (400.1 MHz, DMSO-d6, 25 °C): d = 4.56–4.40
(br s, 2H, OCH2), 3.06 (s, 3H, NCH3), 3.02 (s, 3H, NCH3), 1.68–1.55
m = 1640, 1468, 1383,
.
Table 4
Crystallographic data for compounds 2a, 3a, 4b, 5aꢀDMSO and 6aꢀDMSO.
2a
3a
4b
5aꢀDMSO
6aꢀDMSO
Empirical formula
Mw
C
12H26Br4N2O4Sn2
C8H17Br2NO2Sn
451.76
C24H30Br4N2O6Sn2
999.52
C8H19Cl2NO3SSn
398.89
C9H19Cl2NO3SSn
410.40
819.37
T (K)
100(2)
100(2)
100(2)
100(2)
100(2)
Size (mm)
Space group
a (Å)
b (Å)
c (Å)
0.16 ꢂ 0.12 ꢂ 0.10
0.25 ꢂ 0.16 ꢂ 0.12
0.15 ꢂ 0.12 ꢂ 0.10
0.36 ꢂ 0.35 ꢂ 0.29
0.21 ꢂ 0.17 ꢂ 0.13
P21/c
P21/c
Pbca
P21/c
P21/c
14.1935(8)
14.5891(8)
11.3952(6)
104.0050(10)
2289.5(2)
4
2.377
9.180
1536
7.7675(18)
14.882(4)
11.791(3)
102.577(4)
1330.3(5)
4
2.256
7.911
864
9.9829(13)
15.273(2)
19.742(3)
90
3010.1(7)
4
2.206
7.010
1904
11.1337(4)
9.4847(4)
14.9293(6)
111.3220(10)
1468.62(10)
4
1.804
2.239
792
11.0622(8)
9.5005(7)
15.3362(11)
111.0160(10)
1504.56(19)
4
1.812
2.188
814
b (°)
V (Å3)
Z
qcald (g * cmꢁ3
)
Absorption coefficient (mmꢁ1
F(000)
)
h range (°)
No. of collected/unique reflections
Rint
2.31–30.53
21526/5469
0.0428
2.24–27.59
18164/3244
0.0722
2.44–28.60
37134/2779
0.1606
2.60–31.24
19192/4415
0.0212
2.573–34.554
25004/4024
0.0320
Data/restraints/parameters
Goodness of fit on F2
7024/0/223
0.996
4473/0/130
0.955
4601/0/172
1.059
4692/0/150
1.028
4412/0/158
1.043
R1 (I > 2
r
(I))
0.0304
0.0343
0.0573
0.0173
0.0178
wR2 (all data)
0.0569
1.072/ꢁ0.957
0.0702
0.890/ꢁ1.343
0.1271
2.127/ꢁ1.505
0.0391
0.522/ꢁ0.589
0.0405
0.538/ꢁ0.379
Largest different peak/hole (e/Å3)

D.V. Airapetyan et al. / Inorganica Chimica Acta 432 (2015) 142–148
147
3
(m, 2H, SnCH2), 1.18 (t, JH,H = 7.8 Hz, 2H, CH3) ppm. 119Sn NMR
Service http://www.ccdc.cam.ac.uk/Community/Requestastructure/
pages/Requestastructure.aspx.
(106.2 MHz, DMSO-d6, 25 °C): d = ꢁ427.4 and ꢁ417.5 ppm.
Found: C 17.49, H 3.10, N 3.45. C6H13NO2SnBr2. Calcd. C 17.56, H
3.17, N 3.41.
4. Conclusions
3.2.3. Synthesis of compound 3a
In conclusion, the bromides 2a, 3a, 4b were synthesized via
interaction of monoorganotin tribromides (RSnBr3; R = Et, n-Bu,
Ph) with O-TMS derivatives of N,N-disubstituted amides of glycolic
acid (1a,b). It was established in the solid state that 2a, 3a, 4b
(X-ray analysis) are dimeric and found to be similar to the analo-
gous chlorides. In solution the behavior of these bromides differs
significantly from the related chlorides. The dynamic equilibrium
between dimer and monomer adducts with DMSO molecules is
observed. In the case of related chlorides 5a, 6a, 7b the equilibrium
is shifted toward monomers, for 5a and 6a the crystalline
monomer adducts with DMSO were isolated and studied by
X-ray analysis.
The mixture of n-BuSnBr3 (1.00 g, 2.40 mmol) and 1a (0.42 g,
2.40 mmol) in acetonitrile (15 mL) was refluxed for 8 h. After cool-
ing to room temperature diethyl ether (20 mL) was added and the
resulting mixture was kept at 4 °C overnight. The precipitate was
filtered off, washed with diethyl ether and dried in vacuum to yield
0.20 g (19%) of 3a as white crystals, m. p. 170–171 °C. IR (KBr):
m
= 1637, 1491, 1410, 1051 cmꢁ1 1H NMR (400.1 MHz, DMSO-d6,
.
25 °C): d = 4.53 (br s) and 4.44 (br s) (2H, OCH2), 3.06 (s, 3H,
NCH3), 3.02 (s, 3H, NCH3), 1.76–1.29 (m, 6H, SnCH2CH2CH2), 0.86
3
(t, JH,H = 7.3 Hz, 3H, CH3) ppm. 1H NMR (400.1 MHz, DMSO-d6,
3
65 °C): d = 4.47 (s, J119Sn, H = 87.2 Hz, 2H, OCH2), 3.07 (s, 3H,
2
NCH3), 3.03 (s, 3H, NCH3), 1.72–1.62 (m, J119Sn, H = 131.6 Hz, 4H,
SnCH2CH2), 1.41–1.32 (m, 2H, CH2), 0.86 (t, JH,H = 7.3 Hz, 3H,
3
CH3) ppm. 1H NMR (400.1 MHz, CD3CN, 25 °C): d = 4.57 (br s, 2H,
OCH2), 3.05 (s, 3H, NCH3), 3.00 (s, 3H, NCH3), 2.03–2.19 (m, 2H,
OCH2), 1.70–1.79 (m, 2H, CH2), 1.41–1.51 (m, 2H, CH2), 0.94 (t,
3JH,H = 7.2 Hz, 3H, CH3) ppm. 13C NMR (100.6 MHz, CD3CN, 25 °C):
d = 178.10 (C@O), 62.16 (OCH2), 38.00 (NCH3), 36.74, 29.19, 26.15,
14.35 (Bu) ppm. 13C NMR (100.6 MHz, DMSO-d6, 65 °C):
d = 177.67 (C@O), 59.98 (OCH2), 36.32 (NCH3), 34.77, 27.02, 24.09,
13.02 (Bu) ppm. 119Sn NMR (106.2 MHz, CD3CN, 25 °C):
d = ꢁ344.3 (br s) ppm. 119Sn NMR (106.2 MHz, DMSO-d6, 25 °C):
d = ꢁ425.7 and –431.4 ppm. 119Sn NMR (106.2 MHz, DMSO-d6/
C6D6 (2:1), 25 °C): d = ꢁ424.2 and ꢁ430.5 ppm. 119Sn NMR
(106.2 MHz, DMSO-d6/ C6D6 (1:1), 25 °C): d = ꢁ423.0 ppm. 119Sn
NMR (106.2 MHz, DMSO-d6, 65 °C): d = ꢁ427.9 ppm. Found C
21.88, H 3.74, N 3.28. C8H17NO2SnBr2. Calcd. C 21.92, H 3.88, N 3.20.
Acknowledgements
This work in part was supported partially by M. V. Lomonosov
Moscow State University Program of Development and Russian
Fund for Basic Research (grant 13-03-01084).
Appendix A. Supplementary material
CCDC 1029878–1029882 contains the supplementary crystallo-
graphic data for compounds. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif. Supplementary data associ-
ated with this article can be found, in the online version, at http://
dx.doi.org/10.1016/j.ica.2015.04.006.
3.2.4. Synthesis of compound 4b
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7.20 mmol) in acetonitrile (15 mL) was stirred at ambient temper-
ature for 15 h. The precipitate was filtered off, washed with diethyl
ether and dried in vacuum. Yield 1.34 g (37%), white crystalline
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