N-Methyl-N,N-bis(Silatranylmethyl)amine: Structure and reactivity

Article abstract of DOI:10.1016/j.jorganchem.2020.121319

Trimethylsilylacetonitrile Me₃SiCH₂CN and N-methyl-N,N-bis(silatranylmethyl)amine hygrohalogenide were obtained by the interaction of N-methyl-N,N-bis(silatranylmethyl)amine MeN[CH₂Si(OCH₂CH₂)₃N]₂ 1 with MeCN/Me₃SiX (X = Cl, I). The key stage of this reaction is the formation of the intermolecular complexes between amine 1 and Me₃SiX. The alkylation of amine 1 by ICH₂SiX₃ (SiX₃ = SiMe₃, Si(OMe)₃ and Si(OCH₂CH₂)₃N) give rise to the generation of the corresponding ammonium salts {(X₃SiCH₂)MeN[CH₂Si(OCH₂CH₂)₃N]₂}⁺I^-. The molecular structures of N-methyl-N,N-bis(silatranylmethyl)amine (1), N-methyl-N-[(trimethylsilyl)methyl]-N,N-bis(silatranylmethyl)ammonium iodide (4) and N-methyl-N-N,N-tris(silatranylmethyl)ammonium iodide (6) were determined by single-crystal X-ray diffraction. Compound 1 exists as mix of the conformers 1A (values l_N→Si are equal 2.212 ? and 2.274 ?), 1B (values of l_N→Si are equal 2.252 ? and 2.272 ?) and 1C (values l_N→Si are equal 2.273 ? and 2.291 ?). The length of dative bond N→Si of molecules 1A-1C is longer than in molecules 4 and 6 (Δl lie between 0.105 ? and 0.199 ?), but length of Si–CH₂ bond is shorter on 0.001–0.034 ?.

Full text of DOI:10.1016/j.jorganchem.2020.121319

Journal of Organometallic Chemistry 919 (2020) 121319
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
N-Methyl-N,N-bis(Silatranylmethyl)amine: Structure and reactivity
Boris Gostevskii, Alexander Albanov, Alexander Vashchenko, Vladimir Shagun,
Nataliya Lazareva*
A.E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, 1, Favorsky st., 664033, Irkutsk, Russia
a r t i c l e i n f o
a b s t r a c t
Article history:
Trimethylsilylacetonitrile Me3SiCH2CN and N-methyl-N,N-bis(silatranylmethyl)amine hygrohalogenide
were obtained by the interaction of N-methyl-N,N-bis(silatranylmethyl)amine MeN[CH2Si(OCH2CH2)3N]2
1 with MeCN/Me3SiX (X ¼ Cl, I). The key stage of this reaction is the formation of the intermolecular
complexes between amine 1 and Me3SiX. The alkylation of amine 1 by ICH2SiX3 (SiX3 ¼ SiMe3, Si(OMe)3
and Si(OCH2CH2)3N) give rise to the generation of the corresponding ammonium salts {(X3SiCH2)MeN
[CH2Si(OCH2CH2)3N]2}þI-. The molecular structures of N-methyl-N,N-bis(silatranylmethyl)amine (1), N-
methyl-N-[(trimethylsilyl)methyl]-N,N-bis(silatranylmethyl)ammonium iodide (4) and N-methyl-N-N,N-
tris(silatranylmethyl)ammonium iodide (6) were determined by single-crystal X-ray diffraction. Com-
pound 1 exists as mix of the conformers 1A (values lN/Si are equal 2.212 Å and 2.274 Å), 1B (values of
lN/Si are equal 2.252 Å and 2.272 Å) and 1C (values lN/Si are equal 2.273 Å and 2.291 Å). The length of
Received 23 January 2020
Received in revised form
20 April 2020
Accepted 21 April 2020
Available online 5 May 2020
Keywords:
N-Methyl-N,N-bis(silatranylmethyl)amine
Trimethylsilylacetonitrile
Deprotonation of acetonitrile
N-Methyl-N-(silyl)methyl-N,N-
bis(silatranylmethyl)ammonium iodide
dative bond N/Si of molecules 1A-1C is longer than in molecules 4 and 6 (
0.199 Å), but length of SieCH2 bond is shorter on 0.001e0.034 Å.
Dl lie between 0.105 Å and
© 2020 Elsevier B.V. All rights reserved.
1. Introduction
these compounds runs very easy and gives rise to formation of
corresponding radical cations [28e33]. Our recent studies have
Silatranes
(2,8,9-trioxa-5-aza-1-silatricyclo-[3.3.3.01,5]unde-
shown that
high reactivity [34e39]. These compounds are typical
and they are involved in the single electron transfer reactions. The
interaction of -(silatranylmethyl)amines with CCl4 under the irra-
diation of daylight lead to the formation of the corresponding 1-
(aminomethyl)silatranes hydrochloride in high yields. The in-
a
-(silatranylmethyl)amines RR’NCH2Si(OCH2CH2)3N are
canes) RSi(OCH2CH2)3N are key compounds in the chemistry of
organic derivatives of the pentacoordinate silicon atom, which are
well studied by various methods [1e4]. The unique structural fea-
tures, unusual spectral characteristics and reactivity of silatranes
are caused by the intramolecular dative bond N/Si [5e7], forming
a tricyclic cage with a trigonal bipyramidal silicon atom. The high
relevance of the study of these compounds still remains, which is
confirmed by recent publications [8e20].
a-silylamines
a
termediates of this reaction are a carbon-centered radicals of
a-
(silatranylmethyl)amines. Their existence was proved by ESR spec-
troscopy at the interaction of N-methyl-N,N-bis(silatranylmethyl)
amine with tetrachloromethane [35]. According to the assumed
mechanism of this reaction the cation radical of amine can be formed
on the first stage reaction. However they were not detected under
the conditions of these experiments. The formation of cation radical
of N-methyl-N,N-bis(silatranylmethyl)amine was proved by ESR
spectroscopy at the investigation of the reaction of this silatrane with
AgNO3 [36]. The significant donor inductive effect of the sila-
a-Silylamines RR’NCH2SiX3 are original organosilicon compounds
having interesting physico-chemical properties and biological ac-
tivity [21,22]. In particular, silyl group serves as an effective elec-
troauxiliary for the oxidation of the compounds containing SieCeN
group [23,24]. The introduction of the silyl group in a-position to
nitrogen atom allows significantly to decrease the ionization po-
tential of amine. The ionization potentials of a-silylamines are much
lower than those of the organic amines [25e27]. So, for example, the
values of vertical first ionization potentials of N(CH2SiMe3)3 and
Me3N are 7.66 eV and 8.44 eV, respectively [27]. The oxidation of
tranylmethyl group CH2Si(OCH2CH2)3N (
abnormally high basicity of the exocyclic nitrogen atom of
s
* ¼ ꢀ2.24) [40] affords the
a
-(sila-
tranylmethyl)amines [41] and, as a consequence, leads to their high
reactivity.
N-Methyl-N,N-bis(silatranylmethyl)amine 1 belongs among the
poorly explored type of silatranes X(CH2Si(OCH2CH2)3N)2 (X ¼ O, S,
* Corresponding author.
E-mail address: nataly_lazareva@irioch.irk.ru (N. Lazareva).
https://doi.org/10.1016/j.jorganchem.2020.121319
0022-328X/© 2020 Elsevier B.V. All rights reserved.

2
B. Gostevskii et al. / Journal of Organometallic Chemistry 919 (2020) 121319
NR) containing two silatranylmethyl groups at heteroatom with
lone pair and only a few such compounds are described in the
literature [42e44]. Almost 20 years ago we obtained silatrane 1
[42] and for a long time we got failure in the study of its structure by
X-ray crystallography. Continuing these investigations we obtained
the crystals of compound 1, and we describe below the results of
study of its structure by X-ray analysis and some new data about its
reactivity.
Volatile compounds and Et2O have been combined and was
evaporated at 30 mm Hg мм. The rest (2 mL, 0.65 g) is yellowish
liquid. The analysis data of GC-MS show the presence of a molecular
ion [M]þ 113 m/z from Me3SiCH2CN. 1Н (CDCl3
d
ppm): 0.22 c 9H,
; ppm): 1.97 (MeSi), 4.77
; ppmÞ: 4.49.
SiMe3), 1.61 c (2H, CH2). 13С NMR (CDCl3,
(CH2), 119.06 (CN). 29Si NMR (CDCl3,
d
d
2.4. N-Methyl-N,N-bis(silatranylmethyl)amine hydroiodide (3)
2. Experimental section
Compound 3 was obtained by interaction of amine 1 (1.59 g,
3.92 mmol) with Me3SiI (0.79 g, 3.92 mmol), (1 h, 25 оС). Yield
2.08 g (99%, 3.90 mmol), white powder, M. p. 243e244 оС. 1H NMR
2.1. General
(DMSO‑d6,
d
; ppm): 2.20 AB q (4Н, CH2NCH2, 2J ¼ 14.2 Hz), 2.73 s
The 1H, 13C, 29Si and 15N NMR spectra of 10e20% solutions of
compounds in CD3CN, DMSO‑d6 or DMF-d7 were registered on a
(3Н, NMe), 2.97 t (12Н, 6NCH2, J ¼ 5.8 Hz), 3.47 s (1Н, NH), 3.72 t
3
(12Н, 6ОСН2, 3J ¼ 5.8 Hz). 13С NMR (DMSO‑d6,
d; ppm): 45.80
Bruker DPX 400 and
и
Bruker AV-400 spectrometers (400.1, 100.6,
(NMe), 49.99 (NCH2Si), 53.43 (NCH2), 56,53 (OCH2). 29Si NMR
79.5 and 40.6 MHz respectively) with tetramethylsilane as internal
(DMSO‑d6, d d; ppm): -351.9
; ppm): -84.81.15N NMR (DMSO‑d6,
standard.
(NCH2), ꢀ341.6 (NHMe). Anal. Calcd. for C15H32O6N3Si2I: С 33.77; Н
6.05; N 7.88; Si 10.53; I 23.79. Found: С 33.86; Н 6.12; N 7.96; Si
10.59; I 23.71.
Volatile compounds and Et2O have been combined and was
evaporated at 30 mm Hg. Me3SiCH2CN was obtaihed by distillation.
Yield 0.30 g (2.65 mmol, 68%), B. p. 65e70 oС/20 mm Hg, nD20 1.4208.
The spectral data are identical by the above parameters.
The GC-MS analysis was performed on a SHIMADZU-GCMS-
QP5050 (chromatography column Ultra 2). Elemental analysis is
performed on the Thermo Scientific Flash 2000 Automatic CHNS
Analyzer. All reactions were performed in the Schlenk vessels in
an argon atmosphere. The used solvents MeCN, Et2O, THF and
MeOH were purified according to standard procedures [45]. THF
and Et2O were continuously refluxed and freshly distilled from
sodium benzophenone ketyl under nitrogen and stored over
molecular sieves 4A. Me3SiCl, Me3SiI were purchased from Alfa
Aesar and used as received. Triethanolamine was purified by low-
pressure distillation and stored over molecular sieves 4A. N-
Methyl-N,N-bis(silatranylmethyl)amine synthesized according to
Ref. [42] and its monocrystal for X-ray analysis was obtained by
recrystallisation from THF. The melting point of compounds 2e6
was determined in vacuumed capillaries. ICH2SiMe3 was pre-
pared according to literature procedure [46]. ICH2Si(OMe)3 and
ICH2Si(OCH2CH2)3N were obtained according to literature pro-
cedures [47,48].
2.5. N-Methyl-N-[(trimethylsilyl)methyl]-N,N-bis(silatranylmethyl)
ammonium iodide (4)
Compound 4 was obtained by interaction of amine 1 (1.32 g,
3.25 mmol) with ICH2SiMe3 (0.71 g, 3.32 mmol), (3 h, 100 оС). Yield
1.98 g (98%, 3.21 mmol), white powder, M. p. 264.3 оС. 1H NMR
(CD3CN,
d; ppm): 0.18 s (9H, SiMe3), 2.66 q (4H, 2NCH2,
2J ¼ 14.7 Hz), 2.93 t (12Н, 6NCH2, 3J ¼ 5.98 Hz), 3.11 s (3Н, NMe),
3.33 s (2H, CH2SiMe3), 3.74 t (12Н, 6ОСН2, 3J ¼ 5.98 Hz). 13С NMR
(CD3CN, d; ppm): 0.22 (SiMe), 51.46 (NCH2), 58.05 (OCH2), 58.59
(NMe), 62.99 (NCH2SiMe3), 65.94 (NCH2). 29Si NMR (CD3CN,
d;
ppm): ꢀ1.76 (CH2SiMe3), ꢀ84.14 (silatrane). 15N NMR (CD3CN,
d;
2.2. General methodology of the interaction of compound 1 with
X(CH2)nSiY3 (X ¼ Cl, I; SiY3 ¼ SiMe3, Si(OCH2CH2)3 N, n ¼ 0, 1)
ppm): ꢀ352.7 (NCH2), ꢀ327.7 (NMe). Anal. Calcd. for
C19H42O6Si3N3I: С 36.82; Н 6.83; N 6.78; Si 13.60; I 20.48. Found: С
36.90; Н 6.75; N 6.54; Si 13.81; I 20.43. Crystals for X-ray analysis
The compound 1 was placed in a carefully dried and the argon-
filled Schlenk vessel equipped with a magnetic stirrer. The vessel
was evacuated and dry MeCN (10 mL) was condensed. Then, the
corresponding silane was added in one portion through a glass
adapter with a rubber tube. The Teflon high-vacuum valve of
Schlenk flask was closed and the reaction mixture was stirred (the
reaction time and temperature are indicated below for each com-
pound). Volatile compounds were removed in vacuo. The rest was
washed with dry diethyl ether (2 ꢁ 30 mL), which was removed by
decantation, the product was dried in vacuum.
were obtained by recrystallisation from MeCN.
2.6. N-Methyl-N-[(trimethoxysilyl)methyl]-N,N-
bis(silatranylmethyl)ammonium iodide (5)
Compound 5 was obtained by interaction of amine 1 (1.61 g,
3.96 mmol) with ICH2Si(OMe)3 (1.24 g, 4.75 mmol), (3 h, 100 оС).
Yield 2.65 g (96%, 3.82 mmol), white powder, M. p. 182e184 оС. 1H
NMR (CD3CN,
d
; ppm): 2.74 AB q [4Н, 2СН2Si, 2JAB ¼ 14.5 Hz], 2.94 t
[12H, 2NCH2, 3J
¼
5.9 Hz), 3.11
s
(3Н, NMe), 3.36
s
[2H,
[12H, CH2O,
d; ppm): 51.52 [N(CH2CH2O)3Si],
NCH2Si(OMe)3], 3.59
s [9H, (MeO)3Si], 3.75 t
2.3. N-Methyl-N,N-bis(silatranylmethyl)amine hydrochloride (2)
3J ¼ 5.9 Hz). 13С NMR (CD3CN,
51.56 (SiOMe), 55.73 (NCH2SieOMe), 57.90 (NMe), 58.10
Compound 2 was obtained by interaction of amine 1 (1.44 g,
3.55 mmol) with Me3SiCl (0.38 g, 3.56 mmol), (4 h, 25 оС). Yield
1.51 g (96%, 3.42 mmol), colorless crystals, M. p. 272e273 оС. 1H
[N(CH2CH2O)3Si], 6.76 [NCH2Si(OCH2CH2)3N]. 29Si NMR (CD3CN,
d
;
ppm): -54.81 (Si(OMe)3), - 84.16 (silatrane). 15N NMR (CD3CN,
d;
ppm): ꢀ352.9 (NCH2), ꢀ330.8 (NMe). Anal. Calcd. for
NMR (DMSO‑d6,
d
; ppm): 2.10 AB dd (2HA, NCH2Si 2J ¼ 14.2 Hz,
C19H42O9Si3N3I: С 34.18; Н 6.34; N 6.29; Si 12.62; I 19.00. Found: С
3JNHCH2
¼
6.7 Hz), 2.21 dd (2НB, NCH2Si, 2J
¼
14.2 Hz,
34.10; Н 6.42; N 6.11; Si 12.83; I 18.56.
3JNHCH2 ¼ 3.2 Hz), 2.69 d (3Н, NMe, 3J ¼ 4.7 Hz), 2.96 t (12Н, 6NCH2,
3J ¼ 5.8 Hz), 3.72 t (12Н, 6ОСН2, 3J ¼ 5.8 Hz) 6.69 s (1Н, NH). 13
С
2.7. N-Methyl-N-N,N-tris(silatranylmethyl)ammonium iodide (6)
NMR (DMSO‑d6,
d; ppm): 46.06 (MeN), 50.04 (NCH2Si), 53.59
(NCH2), 56.58 (OCH2). 29Si NMR (DMSO‑d6,
NMR (DMSO‑d6,
d
; ppm): -84.60.15
N
Compound 6 was obtained by interaction of amine 1 (1.54 g,
3.80 mmol) with ICH2Si(OCH2CH2)3N (1.20 g, 3.80 mmol) in 30 mL
dry acetonitrile, (20 h, 120 оС). Yield 1.50 g (55%, 2.09 mmol), white
d
; ppm): -351.8 (NCH2), ꢀ340.6 (NHMe). Anal.
Calcd. for C15H32O6N3Si2Cl: С 40.76; Н 7.30; N 9.51; Si 12.71; Cl 8.02.
Found: С 40.68; Н 7.26; N 9.60; Si 12.82; Cl 8.13.
crystals, M. p. 305 оС. 1H NMR (DMF-d7,
d; ppm): 2.84 s (6H,

B. Gostevskii et al. / Journal of Organometallic Chemistry 919 (2020) 121319
3
3NCH2), 2.98 t (18Н, NCH2, 3J ¼ 5.9 Hz), 3.21 s (3Н, NMe), 3.76 t
3. Results and discussion
(18Н, ОСН2,3J ¼ 5.9 Hz). 13С NMR (DMF-d7,
d; ppm): 5.14 (СН2N),
57.83 (NMe), 57.85 (CH2O), 64.98 (NCH2). 29Si NMR (DMF-d7,
d;
3.1. The interaction of amine 1 with X(CH2)nSiY3 (X ¼ Cl, I; SiY3
SiMe3, Si(OCH2CH2)3 N, n ¼ 0, 1)
¼
ppm): -82.29. Anal. Calcd. for C22H45O9Si3N4I: С 36.66; Н 6.29; N
7.77; Si 11.69; I 17.61. Found: С 36.51; Н 6.31; N 7.21; Si 10.94; I
17.54. Crystals for X-ray analysis were obtained by recrystallisation
from MeOH.
Over many years, a large body of knowledge about neutral inter-
molecular complexes of the different halosilanes with base has been
accumulated. Among them complexes silanes with nitrogen bases
have attracted increased attention. The trifluoro(phenylethynyl)
silane with pyridine forms a pentacoordinate complex PhC≡CSiF.3Py
through intermolecular interaction N/Si [51]. The first X-ray
diffraction study of complex of two pyridine molecules with SiCl4 has
shown that this complex has a octahedral configuration with the
pyridine molecules in axial positions [52]. Complexes of HnSiCl4-n
(n ¼ 1, 2) and RSiCl3 (R ¼ Me, Ph) with pyridine, 3-picoline, 1,10-
phenanthroline, 2,20-bipyridine and N,N,N0,N0-tetramethylethylene-
diamine were obtained and characterized by spectral and X-ray
methods [53e55]. The existence of a specific 1:2 molecular com-
plexes between the free bases meso-tetraarylporphyrins and Me3SiCl
or t-BuSiMe2Cl in chloroform at room temperature was proved by
spectrlal methods [56].
2.8. X-ray analysis
The molecular structures of compounds 1, 4 and 6 were deter-
mined by single-crystal X-ray diffraction. Crystal data were
collected on a Bruker D8 Venture diffractometer with detector
Photone 100 using the
u - 2q scans. Reflection intensity was inte-
grated by using Bruker SAINT software [49]. Accounting for the
absorption of X-rays by a crystal was introduced from an analysis of
the intensities of equivalent reflections. After averaging the in-
tensities of the equivalent reflexes, only independent reflexes were
used. The structures were solved and refined by direct methods
using the SHELX programs set [50]. Non-hydrogen atoms were
refined anisotropically using SHELX [50]. Crystallographic data for
the structure reported in this paper have been deposited with the
Cambridge Crystallographic Data Centre as supplementary publi-
cation CCDC 1936847, CCDC 1936848 and CCDC 1936849. These
data can be obtained free of charge from the Cambridge Crystal-
lographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
Details of crystallographic data and experimental conditions are
presented in Table 1.
In this work we explored the interaction of amine 1 with trime-
thylhalogenosilanes Me3SiX (X ¼ Cl, I) in acetonitrile. We expected
that these silanes will be able to the formation of intermolecular
complexes with compound 1 with the participation of its exocyclic
nitrogen atom. However the trimethylsilylacetonitrile and corre-
sponding
N-methyl-N,N-bis(silatranylmethyl)amine
hydro-
halogenide 2a,b were isolated as a result of this reaction (Scheme 1).
Table 1
Crystallographic data and experimental conditions.
Compound
1
4
6
1936849
3(C15H31N3O6Si2)
1936847
I$C19H42N3O6Si3
619.72
1936848
1(I)$C22H45N4O9Si3
720.79
Empirical formula
Formula weight/g$molꢀ1 1216.82
Crystal system
Space group
a/Å
orthorhombic
Pca21
monoclinic
P 21/n
trigonal
R-3
42.566(19)
10.385(4)
13.320(7)
90
5888(5)
4
7.024(4)
27.247(13)
14.560(8)
90, 100.49(3), 90
2740(2)
14.343(6)
14.343(6)
24.899(11)
90, 90, 120
4436(4)
6
b/Å
c/Å
ꢂ
a, b, g/
Volume/Å3
Z
4
Density (calculated)/
1.373
1.502
1.619
g$cmꢀ3
Absorptions coefficient/ 0.22
1.34
1.26
mmꢀ1
Radiation (
Temperature/K
range/ꢂ
l
/Å)
MoK
293(2)
4.4e55.8
a
(0.71073)
MoK
293(2)
5.0e51.0
a
(0.71073)
MoKa (0.71073)
100.15(2)
4.8e50.4
2
Q
Crystal size/mm
Crystal habit
F(000)
0.26 ꢁ 0.22 ꢁ 0.11
clear, prism, colorless
2616
0.50 ꢁ 0.29 ꢁ 0.13
colorless prism
1280
0.32 ꢁ 0.30 ꢁ 0.11
clear, cube, colorless
2232
Index ranges
Reflections collected
Independent reflections 13,348
Number of ref.
parameters
ꢀ52 ꢃ h ꢃ 54, ꢀ13 ꢃ k ꢃ 13, ꢀ17 ꢃ l ꢃ 17 ꢀ8 ꢃ h ꢃ 8, ꢀ33 ꢃ k ꢃ 33, ꢀ17 ꢃ l ꢃ 18
ꢀ18 ꢃ h ꢃ 18, ꢀ18 ꢃ k ꢃ 17, ꢀ32 ꢃ l ꢃ 32
53,428
56,123
5430
321
49,720
2267
120
707
R1/wR2 [I > 2
s
(I)]
0.0665/0.1263
0.1547/0.1603
1.00
0.71/ꢀ0.47
0.0302/0.0657
0.0424/0.0701
1.05
0.40/ꢀ0.54
0.0226/0.0590
0.0238/0.0595
1.11
2.00/ꢀ0.65
R1/wR2 (all data)
Goodness-of-fit on F2
Largest diff. peak and
hole/e$Åꢀ3
Weight scheme
w ¼ 1/[
s
2(F2o) þ (0.0708 P)2] where P ¼
w ¼ 1/[
s
2(F2o) þ (0.0287 P)2 ]þ1.9777P] where w ¼ 1/[
s
2(F2o) þ (0.0423 P)2 þ 19.4124P] where
(F2o þ 2F2c)/3
P ¼ (F2o þ 2F2c)/3
P ¼ (F2o þ 2F2c)/3

4
B. Gostevskii et al. / Journal of Organometallic Chemistry 919 (2020) 121319
Scheme 1. Reaction of amine 1 with silanes Me3SiX (X ¼ Cl, I) in acetonitrile.
Acetonitrile is used widely as solvent, but it is also an important
A white sediment was obtained at the interaction of Me3SiCl
with amine 1 in benzonitrile solution. Unfortunately, we failed to
study the structure of this resulting complex. Our difficulty caused
by its sparsely distributed in PhCN as well as its high reactivity with
the majority solvents. We note that the trialkylsilanes Me3SiX
(X ¼ Hal, OTf) form the complexes with Lewis bases [56,63e66].
The stable at room temperature complex [Me3Si(NMI)]þCIꢀ was
obtained by reaction of Me3SiCl with N-methylimidazole (NMI) and
its ionic structure was proved by the X-ray analysis [66]. Probably
the interaction between the intermediates a and b or/and b’
generated in amine 1/Me3SiX/MeCN (X ¼ Cl, I) ternary system gives
rise to Me3SiCH2CN and compound 2 or 3, respectvely. Recently
was showed that the combining the Lewis acid (C2F5)3PF2 with
triethylamine in acetonitrle solution enables the deprotonation of
acetonitrile, affording the salt [HNEt3][P(C2F5)3PF2(CH2CN)] [67].
Compound 1 is typical amine and as nucleophile reacts with
(iodomethyl)silanes ICH2SiX3 giving the corresponding tetraalky-
lammonium iodide 4 and 5 with almost quantitative yield (Scheme
3).
building block in organic synthesis [57]. The trimethylsilylaceto-
nitrile from acetonitrile can be accessed by several different pro-
cesses [58e61]. The electrosynthesis with use of an aluminium
sacrificial anode, Me3SiCl, MeCN and tetrabutylammonium chlo-
ride leads to the production of mixture Me3SiCH2CN and
(Me3Si)2CHCN (in the ratio 7:3) [58]. The interaction of an excess of
(trifluoromethyl)trimethylsilane with tetramethylammonium
fluoride in MeCN solution causes the formation of Me3SiCH2CN
[59]. The direct C-silylation of acetonitrile by system Me3SiCl/Li/
THF give rise to the corresponding a-silylated nitriles in yield 30%
[60]. The interaction of 1,1-bis(trimethylsilyl)-2,2-dimethylhydra-
zine with MeI in acetonitrile proceeds with the cleavage of the SieN
bond and the formation of trimethylsilylacetonitrile and
[Me3NþNHSiMe3]I (92% and 81%, respectively) [61].
The absence of the reaction of the compound 1 with MeCN as
well as the reaction between Me3SiX and MeCN is of special note.
The possible mechanism of the formation of trimethylsilylaceto-
nitrile at the interaction of amine 1 with trimethylhalogenosilanes
Me3SiX (X ¼ Cl, I) in acetonitrile is presented on Scheme 2. First, a
weak hydrogen bond CeH/N (a) between amine 1 (as strong base
[35e37]) and MeCN (as weak CeH acid) can exists and it lead to an
activation of CeH bond of acetonitrile. There is evidence, for
example, that the CeH acids are able to form 1:1 complexes with
guanidine-like N-bases which are fully dissociated in acetonitrile
solution [62,63]. Secondly, the silane Me3SiX has the ability to form
of complexes with amine 1. Both neutral compound with penta-
coordinate silicon atom (b) and the intimate (or solvated) ion pair
(b’) of these complexes can occur in solution.
The reaction between amine 1 and 1-(iodomethyl)silatrane
proceeds slowly and under more rigid conditions (120 ꢂC, 20 h)
affording compound 6 with reasonable yield (only 55%) (Scheme 3).
The lowering of electrophilicity of 1-(iodomethyl)silatrane
compared to (iodomethyl)silanes caused by the significant donor
inductive effect of the silatranylmethyl group CH2Si(OCH2CH2)3N
(
s
* ¼ ꢀ2.24) [40]. There are no the alkylation of amine 1 by 1-
(chloromethyl)silatrane in similar conditions.
The structure of compounds 2e6 was confirmed by NMR
spectroscopy and for compounds 1, 4 and 6 were obtained data X-
ray analysis.
3.2. NMR study
As compared to N-methyl-N,N-bis(silatranylmethyl)amine 1
compounds 2e6 show a significant low-field shift of signals of the
N-СH3 and NeCH2eSi groups in the 1H NMR spectra (Table 2). This
fact gives evidence of the quaternization of the exocyclic nitrogen
atom in compounds 2e6. The alkylation or protonation of the ni-
trogen atom of amine is followed by significant changing of its
properties. In particular, the quaternary ammonium cations exhibit
the electron withdrawing effect
(s* are 0.09 and 4.38 for
eCH2NMe2 and eNþMe3 groups, respectively) [68]. Early the
similar changes in NMR spectra were demonstrated at the forma-
tion of the N-(silatranylmethyl)ammonium salts [36].
3.3. X-ray study
Single crystal X-ray diffraction study of compounds 1, 4 and 6
showed that their molecules crystallize in the orthorhombic Pca21
space group, monoclinic P 21/n space group and trigonal R3 space
group, respectively. The ORTEP view of compounds 1, 4 and 6 are
shown in Figs. 1e3, the selected bond lengths and bond angles are
listed in Table 3. The independent part of the unit cell of compound
1 contains 12 independent conformers 1A, 1B and 1C, there are 4
molecules for every kind. Molecules 1A, 1B and 1C have different
spinning of “propeller blades” i.e. three five-membered
Scheme 2. The possible mechanism of the formation of trimethylsilylacetonitrile.

B. Gostevskii et al. / Journal of Organometallic Chemistry 919 (2020) 121319
5
Scheme 3. The reaction of amine 1 with (iodomethyl)silanes ICH2SiX3.
Table 2
[70]), respectively (Scheme 4). Authors [69] note that the confor-
mation of each chelate ring in nonsubstituted silatrane
RSi(OCH2CH2)3N is exchangeable, and therefore the absolute con-
figurations are not fixed. The independent part of the unit cell of
compound 4 contains four independent molecules and their sila-
Chemical shifts of the signals of the N-СH3 and NeCH2eSi groups in the 1H NMR
spectra.
Compound
d
, ppm
Solvent
Ref.
ReN
NeCH2eSi
trane groups exist in
cell of compound 6 contains 12 molecules and their silatrane
groups exist in L,L,L forms.
D,D forms. The independent part of the unit
1
2
2
3
4
5
6
2.17
2.69
2.82
2.73
3.11
3.11
3.21
1.89
CD3CN
DMSO‑d6
CD3CN
DMSO‑d6
CD3CN
CD3CN
36
this work
36
this work
this work
this work
this work
2.10, 2.21
2.15, 2.37
2.20
2.66
2.74
The coordination polyhedron of the silicon atom in silatrane
groups of molecules 1A, 1B, 1C, 4 and 6 is a slightly distorted
trigonal bipyramid with N atom and CH2 in the axial positions and
three oxygen atoms occupying the equatorial sites. The N/SieCH2
fragment is almost linear (173.9e178.1) in all these compounds.
According to the Cambridge Structural Database [71], the values of
length N/Si in molecules of compound 1, 4 and 6 lie within the
typical range for silatranes (1.964 Å e 2.420 Å) and clearly verify the
existence of SieN dative bond. The lengths of SieCH2 bond in
compound 1, 4 and 6 lie between 1.893 Å and 1.927 Å. The trigonal
bipyramidal (TBP) character he of the silicon atom can be calculated
according to Tamao’s method (Eq. (1) [72]). The values of this
2.84
DMF-d7
coordination cycles in
order pseudo axis. Molecule 1A contains silatrane groups in
L-forms but silatrane groups in molecules 1B and 1C exist in
forms. The definition of or L stereochemistry of silatranes was
suggested by Yuzo Yoshikawa with co-authors for absolute con-
figurations of silatrane [69]. The - and L-forms have a left- and
right-handed propeller (anticlockwise and clockwise orientation
a
-envelope conformation against their third
D
- and
D-
D
D
Fig. 1. Three independent molecules 1A, 1B and 1C found in the asymmetric unite of compound 1. The ORTEP plot is shown in thermal ellipsoids drawn at 50% probability, hydrogen
atoms were omitted for clearity.

6
B. Gostevskii et al. / Journal of Organometallic Chemistry 919 (2020) 121319
Scheme 4.
D- and L-forms silatrane (viewed down the NeSi bond).
,
2
3
3
P
120 ꢀ 1
3
Qn
6
6
7
7
n¼1
he
¼
1 ꢀ
ꢁ 100%
(1)
6
4
7
5
120 ꢀ 109:5
Fig. 2. The molecular structure of compound 4. The ORTEP plot is shown in thermal
ellipsoids drawn at 50% probability, hydrogen atoms were omitted for clearity.
where
Note the length of dative bond N/Si of molecules 1A-1C is
longer than in molecules 4 and 6 ( l lie between 0.105 Å and
q is average of angles OeqeSieOeq
D
0.199 Å), but length of SieCH2 bond is shorter on 0.001e0.034 Å.
The reason of this is high electron withdrawing effect of ammo-
nium groups [68]. The length dative bond N/Si in silatranes
RSi(OCH2CH2)3N decreases on increasing the electronwithdrawing
properties of the axial substituent R [1]. The conservation of the
total order of the axial bonds is one of the fundamental property of
compounds with the pentacoordinate silicon atom: an increase in
the order of the Si/N bond is followed by reduction in the order
ReSi bond [73]. The axial bonds lengths of silatranes 1, 4 and 6 are
subject to this rule.
An unexpected fact is that the geometric parameters of mole-
cule 1A differs essentially from the geometric parameters of mol-
ecules 1B and 1C. So the lengths of dative bond N/Si of L- and D-
conformers in molecule 1A are 2.212 Å and 2.274 Å, respectively.
Conformers 1B, 1C are practically degenerate states and distinc-
tions between the lengths of coordination bonds N/Si of their D-
conformers is substantially under (0.02 Å and 0.018 Å for 1B, 1C,
respectively). As discussed above silatrane groups in molecules 1B
and 1C exist in
D-forms the molecule 1A contains the silatrane
Fig. 3. The molecular structure of compound 6. The ORTEP plot is shown in thermal
ellipsoids drawn at 50% probability, hydrogen atoms were omitted for clearity.
groups in - and L-topological forms. The reason of the formation
D
of silatrane with right- or left-oriented corner of the envelope is a
plane deformation of the CH2 group during the formation of
structure. According to the quantum chemical research conformer
1A is slightly more stability than the conformers 1B and 1C
characteristic for compound 1, 4 and 6 vary from 78.06% to 91.90%.
It must be emphasized that the values of the geometric parameters
of these compounds and previously studied silatranes containing
group eCH2N in axial position are closely (Table 4).
(
D
E ¼ 0.73 kcal/mol). The calculations were carried out within the
GAUSSIAN 09 software package [74] using the B3LYP/6-31G (p, d)
method. The exocylic nitrogen atom in the conformers 1A, 1B and
1C has the pyramidal configuration (the sum of angles
Table 3
The conformation of siatrane groups and select geometrical parameters of compound 1, 4 and 6.
P
N
Conformation of siatrane group
l, Å
f o
,
NeSieCH2
F,
o SieCeNeMe
f o
,
N
he, %
ꢂ
N/Si
SieCH2
CH2eN
MeeN
1A
1B
1C
4
L
2.212
2.274
2.252
2.272
2.273
2.291
2.101
2.107
2.092
1.917
1.893
1.911
1.911
1.897
1.906
1.927
1.918
1.924
1.485
1.493
1.469
1.473
1.468
1.471
1.523
1.523
1.503
1.464
176.23
175.31
176.83
178.13
177.20
175.04
175.90
175.10
173.91
40.85
333.58
331.29
331.46
83.14
79.84
81.02
79.02
79.52
78.06
91.71
91.30
91.90
D
D
D
D
D
D
D
ꢀ50.20
ꢀ64.85
55.35
ꢀ45.47
167.26
ꢀ63.10
ꢀ42.66
73.63
1.455
1.473
1.499
1.531
6
L,L,L

B. Gostevskii et al. / Journal of Organometallic Chemistry 919 (2020) 121319
7
Table 4
The select geometrical parameters of (N-silatranylmethyl)amines.
P
Compound
l, Å
f o
,
NeSieCH2
f,
o N
he, %
Ref.
N/Si
SieCH2
CH2eN
MeeN
MeNHCH2Si(OCH2CH2)3N
(Ph3C)MeNCH2Si(OCH2CH2)3N
PhNHCH2Si(OCH2CH2)3N
2.159
2.179
2.124
2.130
2.078
2.083
2.188
1.902
1.897
1.895
1.921
1.986
1.473
1.482
1.459
1.466
1.503
1.538
1.455
1.461
1.376
1.386
1.482
1.500
1.585
1.478
176.59
176.09
177.59
178.41
176.99
175.67
329.73
337.32
360.00
346.83
87.81
85.81
90.19
89.90
93.81
93.91
34
38
39
[MeNH2CH2Si(OCH2CH2)3N]þClꢀ
34
71
[Me3NCH2Si(OCH2CH2)3N]þ ꢀ
I
(2MeeNeCH2, CH2eNeCH2) is 333.58ꢂ, 331.29ꢂ 331.46ꢂ, respec-
tively). The pyramidal configuration nitrogen atom is usual for the
most part of the non-aromatic amines [71].
References
[1] V. Pestunovich, S. Kirpichenko, M. Voronkov, in: Z. Rappoport, Y. Apeloig
(Eds.), The Chemistry of Organic Silicon Compounds, vol. 2, John Wiley & Sons
Ltd., Chichester, 1998, pp. 1447e1537.
[2] J.K. Puri, R. Singh, V.K. Chahal, Chem. Soc. Rev. 40 (2011) 1791e1840.
[3] M.G. Voronkov, V.P. Baryshok, Pharm. Chem. J. 38 (2004) 3e9.
[4] G. Singh, G. Kaur, J. Singh, Inorg. Chem. Commun. 88 (2018) 11e20.
[5] M.W. Schmidt, T.L. Windus, M.S. Gordon, J. Am. Chem. Soc. 117 (1995)
7480e7486.
[6] M.S. Gordon, M.T. Carroll, J.H. Jensen, L.P. Davis, L.W. Burggraf, R.M. Guidry,
Organometallics 10 (1991) 2657e2660.
[7] A.A. Korlyukov, K.A. Lyssenko, M.Yu Antipin, V.N. Kirin, E.A. Chernyshev,
S.P. Knyazev, Inorg. Chem. 41 (2002) 5043e5051.
Conformers 1A, 1B and 1C are bound together by the short
contacts CeH/HeC between exocyclic groups NCH2Si, fragments
OCH2C and NCH2C of silatrane cage and oxygen atoms. The lenghts
of these contacts fall in the range between 2.246 Å - 2.644 Å (For a
more detailed discussion of the subject see Supp. Inf.). The avail-
ability of these short contacts lead to formation in crystal packing of
alternating zigzag molecular layers which stack down the c-axis. It
is not improbable that the anomaly of the lenght of dative bond
N/Si in molecule 1A is caused by effect of crystal packing.
[8] G. Singh, S. Girdhar, A. Singh, A. Saroa, J.S. Lakhi, S. Khullarb, S.K. Mandal, New
J. Chem. 42 (2018) 6315e6321.
[9] M. Meshgi, R. Zitz, M. Walewska, J. Baumgartner, C. Marschner, Organome-
tallics 36 (2017) 1365e1371.
[10] E.F. Belogolova, G. Liu, E.P. Doronina, S.M. Ciborowski, V.F. Sidorkin,
K.H. Bowen, J. Phys. Chem. Lett. 9 (2018) 1284e1289.
[11] V. Romanovs, V. Sidorkin, E. Belogolova, V. Jouikov, Dalton Trans. 46 (2017)
8849e8854.
[12] S.E. Varjosaari, V. Skrypai, P. Suating, J.J.M. Paolo, T.M. Gilbert, M.J. Adler, Eur. J.
Org Chem. (2017) 229e232.
[13] G. Singh, Sanchita, A. Singh, G. Sharma, P. Kalra, P. Satija, Diksha, S. Soni,
V. Verma, Inorg. Chim. Acta. 490 (2019) 85e92.
[14] C. Hoeksema, M.J. Adler, T.M. Gilbert, J. Phys. Chem. 120 (2016) 9315e9323.
[15] G. Gurjaspreet, S. Rani, J. Inorg. Chem. (2016) 3000e3011.
[16] G. Singh, A. Singh, P. Satija, G. Sharma, Shilpy, J. Singh, J. Singh, K.N. Singh,
A. Kaura, New J. Chem. 43 (2019) 5525e5530.
[17] K.L. Materna, J. Jiang, R.H. Crabtree, G.W. Brudvig, ACS Appl. Mater. Interfaces
11 (2019) 5602e5609.
[18] C.-J. Huang, Y.-Y. Zheng, Langmuir 35 (2019) 1662e1671.
[19] R. Mutneja, R. Singh, V. Kaur, J. Wagler, S. Fels, E. Kroke, New J. Chem. 40
(2016) 1640e1648.
[20] N. Kaur, G. Singh, J. Singh, A. Singh, P. Satija, G. Kaurc, J. Singh, RSC Adv. 8
(2018) 36445e36452.
[21] J.-P. Picard, Can. J. Chem. 78 (2000) 1363e1379.
[22] J.-P. Picard, Adv. Organomet. Chem. 52 (2005) 175e375.
[23] S. Suga, M. Watanabe, J.-i. Yoshida, J. Am. Chem. Soc. 124 (2002)
14824e14825.
[24] J.-i. Yoshida, K. Kataoka, R. Horcajada, A. Nagaki, Chem. Rev. 108 (2008)
2265e2299.
[25] T. Fuchigami, Electrochemistry of organosilicon compounds, in: Z. Rappoport,
Y. Apeloig (Eds.), The Chemistry of Organic Silicon Compounds, 2, Wiley,
Chichester, 1998, pp. 1187e1232.
4. Conclusion
These results show that the N-methyl-N,N-bis(silatranylmethyl)
amine is strong base and good nucleophile. As base this amine gives
rise to the deprotonation of acetonitrile, but this reaction runs only
in the system amine 1/MeCN/Me3SiX (X ¼ Cl, I) and leads to the
formation of Me3SiCH2CN and N-methyl-N,N-bis(silatranylmethyl)
amine hygrohalogenide. The key stage is the formation of the
intermolecular complexes between amine 1 and Me3SiX. Amine 1 is
good nucleophile and its interaction with ICH2SiX3 (SiX3 ¼ SiMe3,
Si(OMe)3 and Si(OCH2CH2)3N gives rise to the formation of the
corresponding ammonium salts 4e6. The structure of compounds
2e6 was confirmed by NMR spectroscopy and compound 1,4 and 6
were investigated by X-Ray method. N-Methyl-N,N-bis(sila-
tranylmethyl)amine is first example amine, containing two groups
CH2Si(OCH2CH2)3N at nitrogen atom. The structural parameters of
silatranyl groups compound 1 and related N-(silatranylmethyl)
amines are closely. The geometry of exocyclic nitrogen atom is
typical for tertiary amines. These results allows us to assume that
the fundamental reason of the strong basicity of exocyclic nitrogen
atom of amine 1 caused by the high donor inductive effect of two
silatranylmethyl group CH2Si(OCH2CH2)3N.
[26] E. Popowski, G. Zingler, Z. Chem. 21 (1981) 139e140.
[27] H. Bock, W. Kaim, M. Kira, H. Osawa, H. Sakurai, J. Organomet. Chem. 164
(1979) 295e304.
Declaration of competing interest
[28] H.C. Jeong, S.H. Lim, Y. Sohn, Y.-I. Kim, H. Jang, D.W. Cho, P.S. Mariano, Tet-
rahedron Lett. 58 (2017) 949e954.
[29] S.H. Lim, D.W. Cho, J. Choi, H. An, J.H. Shim, P.S. Mariano, Tetrahedron 73
(2017) 6249e6261.
[30] S.H. Lim, J. Yi, C.S. Ra, K. Nahma, D.W. Cho, G.Y. Lee, J. Kim, U.C. Yoon,
P.S. Mariano, Tetrahedron Lett. 56 (2015) 3014e3018.
[31] S.H. Lim, H.C. Jeong, Y. Sohn, Y.-I. Kim, D.W. Cho, H.-J. Woo, I.-S. Shin,
U.C. Yoon, P.S. Mariano, J. Org. Chem. 81 (2016) 2460e2473.
[32] H.C. Jeong, S.H. Lim, D.W. Cho, S.H. Kim, P.S. Mariano, Org. Biomol. Chem. 14
(2016) 10502e10510.
[33] S.H. Lim, J. Yi, G.M. Moon, C.S. Ra, K. Nahm, D.W. Cho, K. Kim, T.G. Hyung,
U.C. Yoon, G.Y. Lee, S. Kim, J. Kim, P.S. Mariano, J. Org. Chem. 79 (2014)
6946e6958.
The authors declare that they have no known competing
financial interests or personal relationships that could have
appeared to influence the work reported in this paper.
Acknowledgments
This work was performed with the use of the analytical equip-
ment of the Baikal Center for Collective Use of the SB RAS.
[34] I.V. Sterkhova, I.M. Lazarev, V.I. Smirnov, N.F. Lazareva, J. Organomet. Chem.
775 (2015) 27e32.
Appendix A. Supplementary data
[35] N.F. Lazareva, T.I. Vakul’skaya, I.M. Lazarev, J. Phys. Org. Chem. 22 (2009)
144e154.
[36] N.F. Lazareva, T.I. Vakul’skaya, A.I. Albanov, V.A. Pestunovich, Appl.
Supplementary data to this article can be found online at
https://doi.org/10.1016/j.jorganchem.2020.121319.

8
B. Gostevskii et al. / Journal of Organometallic Chemistry 919 (2020) 121319
Organomet. Chem. 20 (2006) 696e705.
225e231.
[37] N.F. Lazareva, E.I. Brodskaya, G.V. Ratovsky, J. Chem. Soc. Perkin Trans. 2
(2002) 2083e2086.
[61] M.G. Voronkov, B.A. Gostevskii, B.A. Shainyan, V.I. Rakhlin, R.G. Mirskov,
O.S. Makarov, Dokl. Chem. 400 (2005) 17e20.
[38] N.F. Lazareva, I.V. Sterkhova, I.M. Lazarev, V.I. Smirnov, Polyhedron 117 (2016)
377e380.
[62] I. Binkowska, A. Huczynski, B. Brzezinski, A. Jarczewski, J. Mol. Struct. 892
(2008) 188e194.
[39] N.F. Lazareva, I.V. Sterkhova, J. Organomet. Chem. 898 (2019) 120870.
[40] M.G. Voronkov, E.I. Brodskaya, V.V. Belyaeva, T.V. Kashik, V.P. Baryshok,
O.G. Yarosh, Zh. Obshch. Khim. 56 (1986) 621e627.
[41] E.I. Brodskaya, M.G. Voronkov, V.V. Belyaeva, V.P. Baryshok, N.F. Lazareva, Zh.
Obshch. Khim. 63 (1993) 2252e2256.
[42] N.F. Lazareva, E.I. Brodskaya, V.V. Belyaeva, M.G. Voronkov, Russ. J. Gen. Chem.
71 (2001) 815e816.
[43] M.S. Sorokin, M.G. Voronkov, Russ. J. Gen. Chem. 76 (2006) 461e468.
[44] M.G. Voronkov, M.S. Sorokin, V.M. D’yakov, N.N. Vlasova, F.P. Kletsko, Union of
Soviet Socialist Republics, SU, 1976, p. 514841.
[63] G. Schroedera, B. Łeskaa, F. Bartlb, B. Rozalskia, B. Brzezinskia, J. Mol. Struct.
478 (1999) 255e266.
[64] K. Takasu, K. Misawa, M. Yamada, Y. Furuta, T. Taniguchi, M. Ihara, Chem.
Commun. (2000) 1739e1740.
[65] M. Arshadi, D. Johnels, U. Edlund, C.-H. Ottosson, D. Cremern, J. Am. Chem. Soc.
118 (1996) 5120e5131.
[66] K. Hensen, T.H. Zengerlyt, H.M. Uller, P. Pickel, Z. Anorg. Allg. Chem. 558
(1988) 21e27.
[67] J. Bader, B. Neumann, H.-G. Stammler, N. Ignat’ev, B. Hoge, Chem. Eur J. 24
(2018) 6975e6982.
[45] W.L.F. Armarego, C.L.L. Chai, Purification of Laboratory Chemicals, sixth ed.,
Elsevier, 2009.
[68] A.R. Cherkasov, V.I. Galkin, R.A. Cherkasov, Russ. Chem. Rev. 65 (1996)
641e656.
[46] S. Ambasht, S.K. Chiu, P.E. Peterson, J. Queen, Synthesis (1980) 318e320.
[47] B.A. Gostevskii, N.F. Lazareva, Russ. J. Gen. Chem. 88 (2018) 2084e2088.
[48] I.V. Sterkhova, V.I. Smirnov, G.A. Kuznetsova, E.A. Zel’bst, J. Struct. Chem. 57
(2016) 209e212.
[69] M. Tasaka, M. Hirotsu, M. Kojima, S. Utsuno, Y. Yoshikawa, Inorg. Chem. 35
(1996) 6981e6986.
[70] A. Martinez, L. Guy, J.-P. Dutasta, J. Am. Chem. Soc. 132 (2010) 16733e16734.
[71] F.H. Allen, Acta Crystallogr. B 58 (2002) 380e388.
[49] Bruker Saint, AXS Inc., Madison, Wisconsin, USA, 2013.
[72] K. Tamao, T. Hayashi, Y. Ito, Organometallics 11 (1992) 2099e2114.
[73] V.A. Pestunovich, V.F. Sidorkin, O.B. Dogaev, M.G. Voronkov, Dokl. Akad. Nauk
SSSR 251 (1980) 1140e1143.
[50] G.M. Sheldrick,
A short history of SHELX, Acta Crystallogr. D64 (2008)
112e122.
[51] M. Nakash, M. Goldvaser, J. Am. Chem. Soc. 126 (2004) 3436e3437.
[52] O. Bechstein, B. Ziemer, D. Hass, S.I. Trojanov, V.B. Rybakov, G.N. Maso,
Z. Anorg. Allg. Chem. 582 (1990) 211e216.
[74] M.J. Frisch, G.W. Trucks, H.B. Schlegel, G.E. Scuseria, M.A. Robb,
J.R. Cheeseman, G. Scalmani, V. Barone, B. Mennucci, G.A. Petersson,
H. Nakatsuji, M. Caricato, X. Li, H.P. Hratchian, A.F. Izmaylov, J. Bloino,
G. Zheng, J.L. Sonnenberg, M. Hada, M. Ehara, K. Toyota, R. Fukuda,
J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, T. Vreven,
J.A. Montgomery, J.E. Peralta, F. Ogliaro, M. Bearpark, J.J. Heyd, E. Brothers,
K.N. Kudin, V.N. Staroverov, R. Kobayashi, J. Normand, K. Raghavachari,
A. Rendell, J.C. Burant, S.S. Iyengar, J. Tomasi, M. Cossi, N. Rega, J.M. Millam,
M. Klene, J.E. Knox, J.B. Cross, V. Bakken, C. Adamo, J. Jaramillo, R. Gomperts,
R.E. Stratmann, O. Yazyev, A.J. Austin, R. Cammi, C. Pomelli, J.W. Ochterski,
R.L. Martin, K. Morokuma, V.G. Zakrzewski, G.A. Voth, P. Salvador,
J.J. Dannenberg, S. Dapprich, A.D. Daniels, O. Farkas, J.B. Foresman, J.V. Ortiz,
J. Cioslowski, D.J. Fox, Gaussian 09, Revision A.01, Gaussian, Inc., Wallingford,
2009. Gaussian 09.
[53] K. Hensen, T. Stumpf, M. Bolte, C. Na1ther, H. Fleischer, J. Am. Chem. Soc. 120
(1998) 10402e10408.
€
[54] G.W. Fester, J. Wagler, E. Brendler, U. Bohme, D. Gerlach, E. Kroke, J. Am. Chem.
Soc. 131 (2009) 6855e6864.
[55] G.W. Fester, J. Eckstein, D. Gerlach, J. Wagler, E. Brendler, E. Kroke, Inorg.
Chem. 49 (2010) 2667e2673.
[56] D. Mohajer, S. Rayati, New J. Chem. 27 (2003) 242e244.
[57] B.H. Hoff, Synthesis 50 (2018) 2824e2852.
[58] T. Constantieux, J.-P. Picard, Synth. Commun. 27 (1997) 3895e3907.
[59] D.J. Adams, J.H. Clark, L.B. Hansen, V.C. Sanders, S.J. Tavener, J. Fluor. Chem. 92
(1998) 123e125.
[60] A. Ekouya, J. Dunogues, N. Duffaut, R. Calas, J. Organomet. Chem. 148 (1978)