Structural and Energetic Features of Group 13 Element Trispentafluorophenyl Complexes with Diethyl Ether

Article abstract of DOI:10.1002/ejic.202000815

The complexes of group 13 element trispentafluorophenyl derivatives E(C₆F₅)₃ (E = B, Al, Ga, In) with diethyl ether of 1:1 composition have been synthesized and structurally characterized. All compounds are isostructural.

Full text of DOI:10.1002/ejic.202000815

European Journal of Inorganic Chemistry
Accepted Article
Title: Structural and energetic features of group 13 element
trispentafluorophenyl complexes with diethyl ether.
Authors: Igor V Kazakov, Anna S Lisovenko, Nadezhda A. Shcherbina,
Ilya V. Kornyakov, Nikita Yu. Gugin, Yurii V. Kondrat'ev,
Anna M. Chernysheva, Artem S. Zavgorodnii, and Alexey Y
Timoshkin
This manuscript has been accepted after peer review and appears as an
Accepted Article online prior to editing, proofing, and formal publication
of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
published online in Early View as soon as possible and may be different
to this Accepted Article as a result of editing. Readers should obtain
the VoR from the journal website shown below when it is published
to ensure accuracy of information. The authors are responsible for the
content of this Accepted Article.
To be cited as: Eur. J. Inorg. Chem. 10.1002/ejic.202000815
Link to VoR: https://doi.org/10.1002/ejic.202000815
01/2020

10.1002/ejic.202000815
European Journal of Inorganic Chemistry
FULL PAPER
Structural and energetic features of group 13 element
trispentafluorophenyl complexes with diethyl ether.
Igor V. Kazakov,[a] Anna S. Lisovenko,[a] Nadezhda A. Shcherbina,[a] Ilya V. Kornyakov,[b] Nikita Y.
Gugin,[a] Yurii V. Kondrat’ev,[a] Anna M. Chernysheva,[a] Artem S. Zavgorodnii,[a] and Alexey Y.
Timoshkin* [a]
Abstract: The complexes of group 13 element trispentafluorophenyl
derivatives E(C6F5)3 (E = B, Al, Ga, In) with diethyl ether of 1:1
composition have been synthesized and structurally characterized. All
compounds are isostructural. Thermal stability studies reveal that at
Lewis acidity of E(C6F5)3 plays an important role in their
catalytic activity. In practice, computed and, if available,
experimental values of affinity towards fluoride or hydride ions
(FIA and HIA, respectively), are often used. The calculated and
experimental Lewis acidity orders for E(C6F5)3 (E = B, Al, Ga, In)
are not consistent. The calculated fluoride ion affinity (FIA) values
for E(C6F5)3 decrease in order Al > B > Ga > In[16] or Al > Ga >
B.[5] The Gutmann-Beckett method,[24,25] based on the 31P NMR
shift of Et3PO complexes, gives Lewis acidity order B > In >
Ga.[16,26] The most consistent computational data, benchmarked
with respect to high level ab initio computations, indicate that
according to FIA (in kJ mol-1), boron compounds are less Lewis
acidic compared to their Al analogs, and Lewis acidity changes
nonmonotonically B (452) < Al (536) > Ga (453). However, HIA
values of E(C6F5)3 are very similar: B (484) ≈ Al (483) ≥ Ga
(479).[27]
elevated
temperatures
all
complexes
decompose
with
pentafluorobenzene evolution. The geometries and thermodynamic
characteristics for the dissociation reactions of the compounds have
been computed using three DFT methods. The 1H NMR α-proton
chemical shifts for the coordinated ether in deuterobenzene and in
CD2Cl2 solutions correlate with gas phase dissociation enthalpies of
the complexes. Potentially high Lewis acidity of B(C6F5)3 is hindered
by the large pyramidalization energy of the acceptor moiety.
Introduction
Lewis acid-base, or Donor-Acceptor (DA) interactions[1,2] play
an important role in modern chemistry. Сompounds of group 13
elements in the oxidation state +3 ER3 (E = B, Al, Ga, In; R – a
halogen atom or an organic substituent) are well-known Lewis
acids.[3,4] In order to increase their Lewis acidity and obtain Lewis
superacids, electron-withdrawing substituents R (perfluoroalkyls
and perfluoroaryls) are widely employed.[5,6] In particular, the
series of E(C6F5)3 (E = B, Al, Ga, In, Tl) compounds is well known.
The first group 13 element trispentafluorophenyl derivative
B(C6F5)3 was reported in 1963.[7,8] A convenient way to synthesize
E(C6F5)3·Et2O (E = B, Al, Ga, In, Tl) by the reaction of a Grignard
reagent C6F5MgBr with a respective group 13 trihalide was
proposed by Pohlmann and Brinckmann.[9] B(C6F5)3 is a perfect
activator for homogeneous metallocene Ziegler–Natta olefin
polymerization catalysts[10,11] and useful compound for other
applications.[12-14] Strong Lewis acidity of E(C6F5)3 (E = Al, Ga, In)
manifests itself in complexes with toluene.[15,16]
Thus, the question on relative Lewis acidity of group 13
E(C6F5)3 derivatives remains open, in particular with respect to
neutral Lewis bases. The length of the DA bond is one of the
important characteristics of DA interaction. For the large number
of molecular complexes there is an inverse relationship between
the DA bond energy and the DA bond distance.[28] Shorter DA
bonds usually have larger dissociation energies, but exceptions
to this rule are also known.[29,30] Experimental DA bond distances
in molecular complexes of group 13 metal halides and
perfluorinated derivatives in the solid state were reviewed.[31]
Recently, a structural study of E(C6F5)3 (E = B, Al, Ga, In)
complexes with neutral N-containing donor acetonitrile was
reported by our group.[32] However, up to now there is no complete
series of structurally characterized E(C6F5)3 complexes with the
same O-donor ligand.
In light with the fact that molecular hydrogen activation can be
achieved using B(C6F5)3 – Et2O FLP,[33] diethyl ether was chosen
as a reference Lewis base for this study. The solid state structures
of boron B(C6F5)3·Et2O[34,35] and gallium Ga(C6F5)3·Et2O[16]
derivatives are known. In this work we report the synthesis, crystal
structures and thermal stability of complexes of group 13 element
trispentafluorophenyl derivatives E(C6F5)3 (E = B, Al, Ga, In) with
diethyl ether. The structural features of E(C6F5)3·Et2O complexes
are compared, and the Lewis acidity trends are analyzed on the
basis of both experimental and computational approaches.
After the discovery of activation of molecular hydrogen by
frustrated Lewis pairs (FLP) based on B(C6F5)3,[17,18] the FLP
chemistry of group 13 trispentafluorophenyl derivatives received
considerable interest.[19-21] FLPs formed on the basis of B(C6F5)3
are useful in many synthetic applications, especially as metal-free
catalysts.[22,23]
[a]
Dr. I. V. Kazakov, Dr. A. S. Lisovenko, BS. N. A. Shcherbina, MS. N.
Y. Gugin, Dr. Y. V. Kondrat’ev, MS. A. M. Chernysheva, Dipl. Sci. A.
S. Zavgorodnii, Prof. Dr. A.Y. Timoshkin,
Results and Discussion
Institute of Chemistry, St. Petersburg State University
Universitetskaya emb. 7/9, St. Petersburg, 199034 Russia
E-mail: a.y.timoshkin@spbu.ru Homepage: www.timoshkin.spb.ru
Dr. I. V. Kornyakov
Institute of Earth Sciences, St. Petersburg State University
Universitetskaya emb. 7/9, St. Petersburg, 199034 Russia
Structural features. All compounds crystallize in a triclinic
space group (Table 1). Reported in this work crystal parameters
of 1 and 3 are in good agreement with previous data.[16,34,35] The
[b]
Supporting information for this article is given via a link at the end of
the document.
1
This article is protected by copyright. All rights reserved.

10.1002/ejic.202000815
European Journal of Inorganic Chemistry
FULL PAPER
X-ray crystallographic analysis of 1-4 reveals a distorted
tetrahedral geometry on the central atom (Fig. 1). The sum of C-
E-C valence angles increases in order B < Al < Ga < In from 336º
to 349º, indicating a lesser pyramidalization of heavier group 13
elements.
The E-O bond length expectedly increases from boron to
indium (B-O 1.611(2) Å, Al-O 1.8782(11) Å, Ga-O 2.0192(13) Å,
In-O 2.218(2) Å) in accord with the increase of covalent radii of
elements 0.88, 1.25, 1.25, 1.50 Å.[36]
The structural data on complexes of group 13 triaryls with ether
and THF are summarized in Table 2. The fluorination of phenyl
groups leads to expected shortening of E-O bond length
complexes due to the Lewis acidity increase. The substitution of
hydrogen atoms in a phenyl group by alkyls leads to larger
differences in O-E-C angles; increases the E-O bond length as a
result of a steric bulk and decreases Lewis acidity of EAr3.
According to the experimental E-O bond distances, THF is a
stronger Lewis base than Et2O (Gutmann donor numbers are 20.0
and 19.2, for THF and Et2O, respectively).[37]
Figure 1. Molecular structure of 2 as an example of isostructural compounds
1-4. Ellipsoids are given at 50% probability level. Hydrogen atoms are
omitted for clarity.
Mass spectrometry studies. Volatility and thermal stability of
complexes were studied by mass spectrometry in a temperature
range 50−300 °C (see SI for details). In the mass spectrum of 1
the molecular ion of complex or ions containing both boron and
oxygen atoms were not observed in all temperature range. At
relatively low temperature (60 °C) a high intensity signal of Et2O+
was observed together with a low intensity signal of B(C6F5)3 .
This indicates dissociation of the complex into gaseous Et2O and
solid B(C6F5)3 at 60 °C. Heating to 120 °C results in the increase
of the intensity of a B(C6F5)3+ ion due to B(C6F5)3 vaporization.
+
The fragmentation pattern of a B(C6F5)3 ion above 1 is
analogous to those above pure B(C6F5)3, measured at the same
experimental conditions. It is interesting to note, that in the mass
spectrum above 1 at 110 °C a ion C6F5H+ was detected, while this
ion is absent in the mass spectrum of B(C6F5)3, but it is one of the
decomposition products of the complex B(C6F5)3·Py.[49] Thus,
heating of 1 results in a dissociation of the complex and partial
thermal decomposition with C6F5H evolution.
+
Table 1. Crystal data of 1-4.
Compound
B(C6F5)3·Et2O (1)
C22H10F15OB
586.11
Al(C6F5)3·Et2O (2)
C22H10F15OAl
602.28
Ga(C6F5)3·Et2O (3)
C22H10F15OGa
645.02
In(C6F5)3·Et2O (4)
C22H10F15OIn
690.12
Formula
Mr
Crystal system
Triclinic
Triclinic
Triclinic
Triclinic
̅
P1
̅
P1
̅
P1
̅
P1
Space group
a, Å
b, Å
c, Å
α, °
β, °
γ, °
V, Å3
10.3456(4)
10.6228(3)
10.8012(2)
65.568(3)
85.701(3)
75.773(3)
1047.12(6)
2
10.6434(3)
10.6694(4)
10.9461(3)
74.319(3)
89.385(3)
69.018(3)
1112.28(7)
2
9.8953(5)
10.7061(4)
11.3181(4)
107.861(3)
96.629(4)
98.292(4)
1112.97(8)
2
10.1398(4)
10.9217(4)
11.4558(4)
106.939(3)
98.678(3)
99.372(3)
1170.67(8)
2
Z
ρcalc, g/cm3
1.859
1.799
1.925
1.958
Measurement temperature, K
Crystal size /mm3
Colour
Radiation λ, Å
µ, mm-1
100(3)
100(3)
100(3)
170(3)
0.08×0.06×0.05
colorless
1.54184
1.872
0.09×0.05×0.04
colorless
1.54184
2.155
0.08×0.06×0.04
colorless
1.54184
3.046
0.12×0.10×0.09
colorless
0.71073
1.144
Range of data collection
Measured reflections
Unique reflections
Restraints/parameters
Rint on averaging reflections
Absorption correction
R(|F|) for Fo ≥ 4σ(Fo)
R(|F|) for all reflections
wR(F2) for all reflections
GOOF
8.82-139.98
9950
8.43-139.94
14372
8.33-139.97
10379
6.11-55.00
19901
5370
8/369
0.0312
multi-scan
0.0313
0.0372
0.0793
3965
0/354
0.0314
multi-scan
0.0332
0.0398
0.0883
1.038
0.29/-0.25
4204
0/354
0.0335
multi-scan
0.0334
0.0347
0.0877
1.089
0.34/-0.34
4182
0/354
0.0243
multi-scan
0.0294
0.0309
0.0773
1.037
0.37/-0.57
1.043
0.94/-0.92
Max./min. electron density, e·Å-3
2
This article is protected by copyright. All rights reserved.

10.1002/ejic.202000815
European Journal of Inorganic Chemistry
FULL PAPER
Table 2. Major structural parameters of complexes triarylsubstituted group 13 hydrides with diethyl ether and tetrahydrofurane. Bond
distances in Å, angles in degrees.
Compound
E-O
O-E-C1
108.9(1)
109.63(7)
110.71(4)
109.26(13)
109.09(9)
105.1(2)
106.3(1)
108.01(6)
105.00(7)
103.91(7)
104.65(6)
105.00(6)
107.18(2)
108.6(3)
103.8(1)
106.22(8)
106.68(7)
119.9(5)
102.75(9)
106.96
O-E-C2
108.0(1)
109.26(7)
107.52(4)
108.88(12)
108.99(9)
105.1(2)
O-E-C3
104.6(1)
103.27(7)
103.06(4)
102.92(12)
102.92(9)
104.2(2)
102.8(1)
101.77(6)
102.95(7)
103.39(7)
103.04(7)
103.28(6)
100.49(2)
91.4(2)
Σ(C-E-C)
335.1(2)
336.2(1)
335.4(1)
335.6(1)
335.7(2)
341.0(1)
340.7(2)
338.8(1)
343.1(1)
343.1(1)
343.9(1)
343.3(1)
343.7(1)
348.7(2)
345.7(2)
345.1(2)
345.2(1)
348.4(1)
348.8(1)
354.5(2)
Reference
[34]
[35]
[38]
pres. work
[35]
[40]
[41]
pres. work
[42]
B(C6F5)3·THF
B(C6F5)3·THF*0.5 18-crown-6
B(C6F4H)3·Et2O
B(C6F5)3·Et2O
B(C6F5)3·Et2O
BPh3·THF
Al(C6F5)3·THF
Al(C6F5)3·Et2O
AlPh3·THF
AlPh3·THF
AlPh3·Et2O
AlPh3·Et2O
Al(o-Tol)3·Et2O
AlMes3·THF
Ga(C6F5)3·THF
Ga(C6F5)3·Et2O
Ga(C6F5)3·Et2O
Ga(o-Tol)3·Et2O
In(C6F5)3·Et2O
InMes3·THF
1.585(2)
1.572(1)
1.601(4)
1.611(2)
1.612(2)
1.660(4)
1.859(3)
1.8782(11)
1.893(1)
1.8972(13)
1.920(1)
1.924(1)
1.9282(2)
1.969(5)
1.990(3)
2.018(2)
2.0192(13)
2.107(6)
2.218(2)
2.414(4)
105.9(1)
107.58(6)
103.95(7)
103.75(7)
103.13(6)
103.36(6)
103.36(2)
104.5(3)
[43]
[42]
[44]
[45]
[46]
[47]
[16]
103.7(1)
100.79(9)
98.41(7)
97.75(7)
99.8(3)
99.12(9)
85.93
104.61(7)
104.66(7)
113.4(4)
102.00(10)
101.76
pres. work
[39]
pres. work
[48]
In contrast to 1, its heavier analogues 2, 3, 4 vaporize at
elevated temperatures as evidenced by the observation of low
intensity molecular ions E(C5F3)3Et2O+ at 140-170 °C. However,
the major process, which occurs at lower temperatures (120-
160 °C), is dissociation with Et2O loss. The ion C6F5H+ appears in
the mass spectrum in the same temperature range as Et2O+ ion
(Figure 42S). The low intensity ions E(C6F5)3-nFnEt2O+ (n = 1-2)
were also observed in the mass spectra of 2-4 and can result from
the fragmentation of E(C6F5)3Et2O+ or F/C6F5 exchange.
According to the DFT study, the exchange of C6F5 groups by
chlorine atoms is highly exothermic.[50] It is expected, that a highly
exothermic F/C6F5 exchange may be responsible for the
explosion of the compounds.
Thus, dissociation with Et2O evolution and thermal
decomposition with pentafluorobenzene evolution are the
dominant processes upon heating of complexes 1-4, which occur
in the same temperature range. The irreversible thermal
decomposition precludes the use of tensimetry methods for
studying of such complexes.
Drop-calorimetry studies. Drop-calorimetry measurements at
85 °C with subsequent analysis of volatile products by NMR and
GC-MS methods indicate exothermic decomposition along with
dissociation and sublimation processes. It was found that at 85 °C
1 initially (2.5-8 hours) undergoes a noticeable endothermic
process, followed by slow (up to 21 hours) exothermic
decomposition. The volatile reaction products were trapped and
characterized by 1H and 19F{H} NMR spectroscopy, that revealed
a release of diethyl ether and pentafluorobenzene. The detected
volatile products are in good agreement with the results of the
mass spectrometric study. In each calorimetry experiment white
crystalline material was condensed in the cold part of the
apparatus. Taking into account the absence of B(C6F5)3∙Et2O
complex in the gas phase (vide supra) we attribute the
endothermic process to the heterogeneous dissociation:
amount was insufficient to use for the identification. The average
value for the measured standard brutto enthalpy ΔbruttoH358
(cumulative of processes (1) and irreversible thermal
decomposition of 1) is 198±19 kJ mol-1.
°
In contrast, the drop-calorimetric curves for 2, 3 and 4
exhibit a sharp endothermic peak due to initial heating of the
ampoule and complex, followed by a continuous exothermic peak
(13-29, 13-20 and 23-66 hours for 2, 3 and 4 respectively)
attributed to irreversible thermal decomposition. After the
experiment no solid sublimate was found in the cold part of the
apparatus, indicating that 2, 3 and 4 do not vaporize at 358 K (in
agreement with MS studies, vide supra), while the non-volatile
bulk remained in the measurement cell. In our opinion,
decomposition process for 1-4 can be given by the equation (2):
2 E(C6F5)3∙Et2O(s) = Et2O(g) + (C6F5)2EOE(C6F5)2(s) + 2 C2H4(g) + 2
C6F5H(l)
(2)
The formation of diethyl ether, pentafluorobenzene and
ethylene was confirmed by gas chromatography of volatile
reaction products (see SI for details). Et2O and C6F5H are major
products during decomposition of 2 and 4, while in case of 3 only
traces of Et2O and C6F5H were observed. Solid
(C6F5)2BOB(C6F5)2(s) is
a
known product of ClB(C6F5)2
hydrolysis.[51] The formation of C6F5H in calorimetry experiments
may be due to β-hydride elimination from a C2H5 group. According
to computational studies (see SI for details), ethylene elimination
from ether is facilitated by coordination to the Lewis acid; the
activation energy of this process decreases from 293 kJ mol-1 for
gaseous diethyl ether to 224 and 257 kJ mol-1 for gaseous 1 and
2,. Activation energies for the single step C6F5H and C2H4
elimination from 1 and 2 are 257 and 245 kJ mol-1, respectively.
The average values for the standard enthalpy ΔdecompH358° of
the decomposition process are: −232±6 kJ mol-1 for 2, −6±5 kJ
mol-1 for 3 and −49±8 kJ mol-1 for 4. Independent experiments
reveal that 1-4 are stable in sealed ampoules at 85 °C (no thermal
effect was observed). This indicates that the irreversible
exothermic decomposition process, which was observed in open
ampoules in vacuum, requires dissociation of the complex with E-
O bond breaking.
B(C6F5)3∙Et2O(s) = B(C6F5)3(g) + Et2O(g)
(1)
Upon the completion of the experiment, a small amount of a non-
volatile residue was observed (no more than 4% of the sample
weight), indicating partial irreversible thermal decomposition. The
3
This article is protected by copyright. All rights reserved.

10.1002/ejic.202000815
European Journal of Inorganic Chemistry
FULL PAPER
Table 3. Major structural parameters of gaseous 1-4. Bond
distances in Å, angles in degrees. M06-2X/def2-TZVP level of
theory.
vacant p-orbital of group 13 element E. A linear correlation
between the dissociation energy of the complex and the energy
difference between HOMO of the donor and LUMO of the
acceptor was observed for DA complexes with pyramidal boron
and aluminum-containing acceptors.[52] However, for 2-4 the
difference EHOMO(D)-ELUMO(A) does not change much, and for 1 it
is less negative, which indicates that such correlation[52] is not
appropriate for non-pyramidal Lewis acids.
The charge transfer from donor to acceptor decreases
significantly from 1 to 4 (from 0.44 to 0.17 ē). Note that the amount
of charge transfer is similar for B and Al complexes, in line with
close energies of DA bonds EDA. Interestingly, going from B to In
decreases the amount of charge transferred from O atom. The
percentage of charge transferred from O atom to acceptor moiety
(with respect to the total charge transfer) decreases from 63% for
1 to 53% for 2 and 42 % for 3. In case of 4, upon complex
formation the negative charge on O atom increases by 0.01ē due
to a large electronegativity difference between O and In. Thus,
the observed charge transfer of 0.17ē in 4 occurs from H atoms
of ethyl groups, providing another example of the importance of
the terminal atoms in complex formation.[53] As for the acceptor
moiety, the positive charge on E upon complex formation remains
the same on B atom, but decreases by 0.29, 0.32 and 0.13ē, for
E = Al, Ga, and In, respectively. The B atom transfers electron
density from O atoms of diethyl ether to fluorine atoms of C6F5
groups, while Al and Ga atoms upon complex formation uptake
transferred charge.
Parameter
1
2
3
4
E-O
E-C1
E-C2
E-C3
O-E-C1
O-E-C2
O-E-C3
Σ(C-E-C)
1.611
1.631
1.630
1.630
107.7
109.7
102.5
336.7
1.886
1.980
1.980
1.982
106.0
105.6
99.7
2.026
2.009
2.007
2.008
104.1
103.3
96.9
2.276
2.185
2.183
2.180
99.7
100.6
94.2
343.6
348.6
354.1
Table 4.
Dissociation
∆
dissE, reorganization
∆reorgE,
decomposition ∆decompE, donor-acceptor bond energies EDA (in kJ
mol-1); HOMO-LUMO energy differences EHOMO(D)-ELUMO(A) (in
eV) and Mulliken charge transfer qCT (in ē) for 1-4. M06-2X/def2-
TZVP level of theory.
Property\Compound
1
2
3
4
∆
∆
∆
∆
dissE
84.9
8.9
168.3
6.8
126.3
4.6
117.0
3.8
reorgED
reorgEA
decompE
115.7
94.4
209.6
-6.06
0.44
76.3
213.0
12.9
43.9
35.1
14.5
197.6
219.1
-6.54
0.43
161.1
171.8
109.9
267.1
166.0
-6.42
0.30
119.4
168.5
69.2
302.5
135.2
-6.43
0.17
110.6
171.9
59.4
EDA
EHOMO(D)-ELUMO(A)
qCT
∆dissH°298
∆dissS°298
∆dissG°298
Computational studies. The optimized (M06-2X/def2-TZVP)
geometries of 1-4 (Figure 61S), bond lengths and angles are in
agreement with the experimental findings, as well as computed
and experimental IR spectra for 1-4 (Figures 62S-65S).
Major structural parameters are provided in Table 3.
Expectedly, the computed bond lengths for the gas phase
complexes are slightly longer than the experimental values
determined for the solid state. The donor-acceptor (DA) bond
length expectedly increases from 1.611 Å in 1 to 2.276 Å in 4. The
lengths of E-C bonds also increase monotonically, while the
valence angles O-E-C decrease on going from 1 to 4.
Endothermicity of the decomposition process (eq. 4) increases
from 1 to 4, but the entropy factor is expected to favor
decomposition at high temperatures.
2 E(C6F5)3∙Et2O(g) = Et2O(g) + (C6F5)2EOE(C6F5)2(g) + 2 C2H4(g) + 2
C6F5H(g)
(4)
Interestingly, gas phase dissociation enthalpies of 1-4
1
complexes correlate with the H NMR chemical shift of the α-
proton of diethyl ether both for CD2Cl2 and C6D6 solutions (Figure
2), in line with relative Lewis acidity scales based on downfield
shifts of α-proton resonances of ethers.[54,55] Based on values of
chemical shifts of α-proton of diethyl ether complexes in
deuterobenzene, the following order of Lewis acidity is obtained:
Major computed properties are summarized in Table 4.
E(C6F5)3·Et2O(g) = E(C6F5)3(g) + Et2O(g)
(3)
[56]
[57]
[58]
AlH[N(SiHMe2)2]2
>
AlCl2N(SiMe3)2
>
AlCltBu2
>
>
The thermodynamic characteristics of the dissociation
reactions of complexes (eq. (3)) indicate that thermodynamic
stability of complexes increases in order 1 < 4 < 3 < 2. Thus,
complex 2 is the most thermodynamically stable, while complex 1
is the least stable. This conclusion is in good agreement with
experimentally observed dissociation of 1 in high vacuum.
Table 4 also presents energetic changes, which accompany
tBu3AlClAltBu2
> Al(C6F5)3 > AlPh3·Et2O[42] > Ga(C6F5)3
AlMe3[59] > In(C6F5)3 > Ga(o-Tol)3[39] > B(C6F5)3.
[58]
complex formation: the dissociation energies
∆dissE,
reorganization energies of donor ∆reorgED and acceptor ∆reorgEA
molecules and donor-acceptor bond energies EDA. Note that the
reorganization energy of Et2O does not exceed 9 kJ mol-1, which
indicates that the structure of donor molecule is only slightly
changes during complexation (the Et-O-Et angle increases by 0.7,
2.1, 2.3 and 0.4 degrees for 1-4, respectively). In contrast, ∆reorgEA
values undergo significant decrease in order 1 > 2 > 3 > 4. The
reorganization energy decrease is in accord with the increase of
the sum of C-E-C angles of the acceptor moiety. Note relatively
large reorganization energy of B(C6F5)3 of 116 kJ mol-1, which
leads to a small dissociation energy of 85 kJ mol-1, despite quite
strong donor-acceptor bond energy of 210 kJ mol-1.
Figure 2. Correlation between 1H NMR chemical shifts δ of α-proton of
diethyl ether in complexes 1-4 and gas phase dissociation enthalpies
∆
Expectedly, HOMO of Et2O predominantly consists of occupied
p-orbital of oxygen, while LUMO of E(C6F5)3 is a predominately
dissH°298. Yellow circles: 1H NMR in C6D6, blue rhombs: 1H NMR in CD2Cl2.
4
This article is protected by copyright. All rights reserved.

10.1002/ejic.202000815
European Journal of Inorganic Chemistry
FULL PAPER
E(C6F5)3·Et2O (E = Al, Ga, In) were synthesized by reactions of a
Grignard reagent C6F5MgBr with the respective metal trichloride according
to the literature procedure.[9] Caution: to lower risk of explosion a
rigorous stirring is strongly recommended when refluxing in toluene.
Following by Pohlmann and Brinckmann[9] purification of 2-4 was achieved
using resublimation in vacuum. Caution: sublimation of 2-4 in vacuum
should be made with care, as explosion may take place, initiated by
overheating (150-180 °C).
Conclusions
The complexes of E(C6F5)3·Et2O (E = B, Al, Ga, In) were
synthesized and characterized by single crystal X-ray diffraction,
NMR and IR spectroscopy. For Al(C6F5)3·Et2O and In(C6F5)3·Et2O
the crystal structures were determined for the first time. These
complexes are isostructural and crystallize in the triclinic crystal
̅
system P1 space group. The donor-acceptor E-O bond length
Synthesis of B(C6F5)3·Et2O (1). Compound 1 was obtained by
dissolving tris(pentafluorophenyl)borane (51 mg, 0.01 mmol) in diethyl
ether (0.5 ml). Colorless crystalline material was obtained by slow
evaporation of diethyl ether solution in an argon-filled glove box at room
temperature with quantitative yield. Colorless crystals of 1, suitable for the
X-ray analysis, were collected from crystalline material. 1H NMR (CD2Cl2,
400 MHz): t 1.08 ppm (3JHH = 7.1 Hz, CH3), q 3.48 ppm (3JHH = 7.1 Hz,
expectedly increases from boron to indium.
Thermal stability and volatility of the compounds were
comprehensively studied by mass spectrometry, drop-calorimetry
and gas phase chromatography. On heating, complex
1
undergoes dissociation into components and does not exist in the
gas phase. In contrast, complexes 2-4 are present in vapors, but
undergo irreversible thermal decomposition with evolution of
pentafluorobenzene.
3
CH2). 19F{1H} NMR (CD2Cl2, 376.5 MHz): ddd -163.97 (3JFF = 24 Hz, JFF
4
= 20.5 Hz, JFF = 8.8 Hz, m-F), t -156.81 (3JFF = 20 Hz, p-F), d -135.28
(3JFF = 23 Hz, o-F). 1H NMR (C6D6, 400 MHz): t 0.76 ppm (3JHH = 7.1 Hz,
CH3), q 2.94 ppm (3JHH = 7.1 Hz, CH2). 19F{1H} NMR (C6D6, 376.5 MHz):
The computed dissociation enthalpies of E(C6F5)3·Et2O (E =
B, Al, Ga, In) increase in order B < In < Ga < Al and correlate with
the 1H NMR chemical shifts of α-proton of the coordinated diethyl
ether. Taking into account the reorganization energies of donor
and acceptor moieties, the DA bond energy changes in order Al
> B >> Ga > In. Thus, Al(C6F5)3 is the strongest Lewis acid in the
series with respect to Et2O. Latent Lewis acidity of B(C6F5)3 is
hindered by its large reorganization energy (pyramidalization of
boron center upon complex formation). As was computationally
predicted[60,61] and recently experimentally demonstrated by
Berionni[62], pre-organized rigid pyramidal B-containing Lewis
acids have significantly larger Lewis acidity compared to planar
analogs due to the lowering reorganization energy of the acceptor
moiety.
3
4
ddd -163.41 (3JFF = 24 Hz, JFF = 20.5 Hz, JFF = 8.8 Hz, m-F), t -155.99
(3JFF = 20.6 Hz, p-F), d -134.81 (3JFF = 24 Hz, o-F). IR (KBr, cm-1): 455 w,
576 w, 617 sh, 619 w, 677 m, 684 m, 740 w, 773 m, 808 m, 866 m, 926 w,
975 s, 984 sh, 1045 m, 1095 sh, 1107 s, 1260 m, 1291 m, 1373 sh, 1379
m, 1398 w, 1469 s, 1520 s, 1648 s, 2868 w, 2895 w, 2920 w, 3003 w. CHN
analysis: calc. 45.08% C, 1.72% H; found 45.35% C, 2.51% H. NMR data
are in good agreement with the literature values [23].
Synthesis of Al(C6F5)3·Et2O (2). A Grignard reagent C6F5MgBr
was prepared by the reaction of C6F5Br (3.7 g, 15 mmol) with magnesium
(0.36 g, 15 mmol) in 20 ml of dry Et2O. The dark solution of C6F5MgBr was
filtered. To a stirred solution at 0 °C, a 10 ml of toluene solution of AlCl3
(0.67 g, 5 mmol) was added dropwise over 20 min. After heating to room
temperature overnight, Et2O was distilled off by heating at normal pressure
in argon atmosphere and the remaining toluene solution was refluxed for
20 h. Hot solution (60-80 °C) was filtered and cooled to -30 °C. Dark
crystals were collected and dissolved in 10 ml of toluene at 50-60 °C. By
cooling to -30 °C clear crystals were collected. Purification of the
compound was achieved by sublimation at 165-170 °C under dynamic
vacuum (0.1-1 torr) in a wholeglass apparatus. The apparatus was sealed
and high vacuum was maintained by the molecular zeolite pump. The
second sublimation performed at 160 °C yielded 2 as colorless crystals
(1.35 g, 2.5 mmol), suitable for the X-ray structural analysis. Yield 51%. 1H
NMR (CD2Cl2, 400 MHz): t 1.39 (3JHH = 7.1 Hz, CH3), q 4.43 (3JHH = 6.9
Hz, CH2). 19F{1H} NMR (CD2Cl2, 376.5 MHz): m -161.85 (m-F), tt -152.77
Experimental Section
General procedures. All synthetic procedures were carried out in
an argon-filled glove box Inertlab 2GB or using a standard Schlenk
technique. Diethyl ether (Vecton, pure) and toluene (Vecton, pure) were
dried over Na/benzophenone. D6-deuterobenzene was dried over Na/K
alloy. CD2Cl2 was dried over CaH2. All solvents have been distilled,
degassed by freezing/thawing under vacuum and stored over 3Å
molecular sieves. Bromopentafluorobenzene (ABCR, 99%) was dried over
3Å molecular sieves. Tris(pentafluorophenyl)borane (ABCR, 97%) and
aluminium trichloride (Sigma Aldrich, 99.99%) were purified by sublimation
in vacuum. Gallium and indium trichlorides were synthesized by direct
reaction of respective metal (Ga 99.9999%, In 99.99%) with gaseous
chlorine in wholeglass apparatus[63] and purified by multiple (no less than
3 times) resublimations in vacuum.
NMR measurements were carried out on a Bruker AVANCE 400
spectrometer. TMS and CFCl3 were used as external standards. IR
spectra were obtained on a Shimadzu IRPrestige-21 in KBr pellets. X-ray
powder diffraction was performed on a Bruker D2 Phaser with CuKα
irradiation. Samples were placed into the sealed camera in glove box
under argon atmosphere.
A Thermoscientific ISQ quadrupole mass spectrometer (electron
ionization, 70eV) with Direct Insertion Probe (DIP) equipment was used for
mass spectrometry studies. A 0.5-1 mg of 1-4 were placed in a thin glass
ampoule (10 mm length and 1 mm diameter) in an argon-filled glove box.
Ampoules were opened on air and immediately placed in a DIP. The mass
spectra of the gas phase above 1-4 were measured from 50 °C to 300 °C
with 10 °C/min heating rate.
The brutto-effects of the processes occurring with E(C6F5)3∙Et2O (E
= B, Al, Ga, In) at 85 °C in a vacuum (residual pressure ~ 0.1 torr) were
determined by a drop-calorimetric method with DAC1-1a differential
automatic calorimeter.[64]
4
(3JFF = 19.2 Hz, JFF = 2.4 Hz, p-F), br ddd -122.71 (3JFF = 25.1 Hz,
4
4JFF = 9.9 Hz, JFF = 2.4 Hz, o-F). 1H NMR (C6D6, 400 MHz): t 0.50
(3JHH = 6.9 Hz, CH3), q 3.48 (3JHH = 7.0 Hz, CH2). 19F{1H} NMR (C6D6,
376.5 MHz): m -160.68 (m-F), br tt -150.99 (3JFF = 19.9 Hz, 4JFF = 2.5 Hz,
4
p-F), ddd -122.57 (3JFF = 26.7 Hz, JFF = 10.3 Hz, 4JFF = 2.5 Hz, o-F). IR
(KBr, cm-1): 420 m, 460 w, 509 m, 549 w, 586 w, 615 m, 725 w, 742 w, 769
m, 838 w, 876 m, 958 s, 988 w, 1008 w, 1011 m, 1072 s, 1090 sh, 1190
w, 1194 w, 1271 m, 1358 m, 1393 w, 1452 s, 1516 s, 1533 m, 1646 m,
2870 w, 2935 w, 3030 w. Multiple attempts of CHN analysis for 2 were
unsuccessful (carbon content was lower by 15-20%).
Synthesis of Ga(C6F5)3·Et2O (3). A Grignard reagent C6F5MgBr
was prepared by the reaction of C6F5Br (3.7 g, 15 mmol) with magnesium
(0.36 g, 15 mmol) in 20 ml of dry Et2O. The dark solution of C6F5MgBr was
filtered. To a stirred solution at 0 °C, a 10 ml of toluene solution of GaCl3
(0.88 g, 5.0 mmol) was added dropwise over 20 min. After heating to room
temperature overnight, Et2O was distilled off by heating at normal pressure
in argon atmosphere and the remaining toluene solution was refluxed for
20 h. Hot solution (60-80 °C) was filtered and cooled to -30 °C. Dark
crystals were collected and dissolved in 10 ml of toluene at 50-60 °C. By
cooling to -30 °C clear crystals were collected. Purification of the
compound was achieved by sublimation at 165-170 °C under dynamic
vacuum (0.1-1 torr) in a wholeglass apparatus. The apparatus was sealed
and high vacuum was maintained by the molecular zeolite pump. The
second sublimation performed at 160 °C yielded 3 as colorless crystals
(2.4 g, 3.7 mmol), suitable for the X-ray structural analysis. Yield 74%. 1H
NMR (CD2Cl2, 400 MHz): t 1.27 ppm (3JHH = 7.1 Hz, CH3), q 4.12 ppm
5
This article is protected by copyright. All rights reserved.

10.1002/ejic.202000815
European Journal of Inorganic Chemistry
FULL PAPER
(3JHH = 7.1 Hz, CH2). 19F{1H} NMR (CD2Cl2, 376.5 MHz): m -161.44 (m-F),
t -152.66 (3JFF = 19.4 Hz, p-F), br d -123.62 (3JFF = 24.5 Hz, o-F). 1H NMR
(C6D6, 400 MHz): t 0.59 ppm (3JHH = 7.1 Hz, CH3), q 3.37 ppm (3JHH = 7.1
Hz, CH2). 19F{1H} NMR (C6D6, 376.5 MHz): m -160.44 (m-F), t -151.09
(3JFF = 19.9 Hz, p-F), d -123.65 (3JFF = 26.8 Hz, o-F). IR (KBr, cm-1): 490
w, 523 w, 548 w, 584 w, 615 m, 721 w, 758w, 769 sh, 773 m, 800 m, 836
w, 889 m, 964 s, 993 m, 1026 m, 1061 sh, 1072 s, 1092 sh, 1153 w, 1195
w, 1273 m, 1364 s, 1381 m, 1392 m, 1454 sh, 1469 s, 1512 s, 1628 w,
1643 m, 2934 w, 2970 w, 3000 w. CHN analysis: calc. 40.97% C, 1.56%
H; found 40.94% C, 1.57% H. NMR data are in good agreement with the
literature values.[16]
M06-2X functional provides better qualitative agreement with experimental
observations.[49] Therefore, if not noted otherwise, data obtained at M06-
2X/def2-TZVP level of theory are presented and discussed in the
manuscript. Full data are given in the Supporting information. The
reorganization energies were calculated as energy difference of the
fragment in complex geometry and fragment in optimized ground state
geometry.
Acknowledgments
Synthesis of In(C6F5)3·Et2O (4). A Grignard reagent C6F5MgBr
was prepared by the reaction of C6F5Br (3.7 g, 15 mmol) with magnesium
(0.36 g, 15 mmol) in 20 ml of dry Et2O. The dark solution of C6F5MgBr was
filtered. To a stirred solution at 0 °C, a 10 ml of toluene suspension of InCl3
(1.10 g, 5 mmol) was added dropwise over 10 min. After heating to room
temperature overnight, Et2O was distilled off by heating at normal pressure
in argon atmosphere and the remaining toluene solution was refluxed for
20 h. Hot solution (60-80 °C) was filtered and cooled to -30 °C. Dark
crystals were collected and dissolved in 10 ml of toluene at 50-60 °C. By
cooling to -30 °C clear crystals were collected. Purification of the
compound was achieved by sublimation at 130-140 °C under dynamic
vacuum (0.1-1 torr) in a wholeglass apparatus. The apparatus was sealed
and high vacuum was maintained by the molecular zeolite pump. The
second sublimation performed at 130 °C yielded 4 as colorless crystals
(0.81 g, 1.2 mmol), suitable for the X-ray structural analysis. Yield 23%. 1H
NMR (CD2Cl2, 400 MHz): t 1.20 ppm (3JHH = 7.1 Hz, CH3), q 3.93 ppm
(3JHH = 7.1 Hz, CH2). 19F{1H} NMR (CD2Cl2, 376.5 MHz): m -160.36 (m-F),
t -152.13 (3JFF = 19.2 Hz, p-F), br d -118.11 (3JFF = 24.2, Hz, o-F). 1H NMR
(C6D6, 400 MHz): t 0.63 ppm (3JHH = 7.1 Hz, CH3), q 3.23 ppm (3JHH = 7.1
Hz, CH2). 19F{1H} NMR (C6D6, 376.5 MHz): m -159.24 (m-F), t -150.46
(3JFF = 19.9 Hz, p-F), br d -118.16 (3JFF = 24.4 Hz, o-F). IR (KBr, cm-1): 457
w, 486 w, 505 w, 584 w, 603 w, 721 w, 758 w, 775 m, 782 sh, 835 w, 870
w, 895 m, 960 s, 1012 m, 1022 m, 1030 m, 1056 s, 1077 s, 1115 sh, 1132
w, 1155 w, 1194 w, 1269 m, 1357 s, 1385 m, 1393 m, 1444 sh, 1468 s,
1511 s, 1628 w, 1641 m, 2916 w, 2999 w, 3016 w. Multiple attempts of
CHN analysis for 4 were unsuccessful. NMR data are in good agreement
with the literature values.[16]
This work was financially supported by the Russian Science
Foundation grant 18-13-00196. The work was carried out using
equipment of the resource centers of St. Petersburg State
University ‘‘Centre for Magnetic Resonance”, ‘‘Centre for X-ray
Diffraction Studies”, “Center for Chemical Analysis and Materials
Research” and “Computing Centre”. We thank reviewers for the
helpful comments.
Keywords: Trispentafluorophenyl derivatives • Group 13 Lewis
acids • Complexes • Ether• Structures
[1] E. N. Gur’yanova, I. P. Gol’dshtein, I. P. Romm, Donor–
Acceptor Bond, Wiley, New York, 1975, 366 p.
[2] A. Haaland, Angew. Chem. Int. Ed. 1989, 28, 992-1007.
[3] A. J. Downs (Ed.), The Chemistry of Aluminium, Gallium,
Indium and Thallium, Blackie, London, 1993.
[4] S. Aldridge, A. J. Downs (Eds.), The Group 13 Metals
Aluminium, Gallium, Indium and Thallium, Wiley, New York,
2011, 726 p.
[5] L. O. Muller, D. Himmel, J. Stauffer, G. Steinfeld, J.
Slattery, G. Santiso-Quinones, V. Brecht, I. Krossing,
Angew. Chem., Int. Ed., 2008, 47, 7659 -7663.
[6] L. Greb, Chem. Eur. J. 2018, 24, 17881-17896.
[7] A. G. Massey, A. J. Park, F. G. A. Stone, Proc. Chem. Soc.,
1963, 212.
Structural studies.
For the single crystal X-ray diffraction
experiments, crystals of 1-3 were fixed on a micro mount, and placed on
an Agilent Technologies SuperNova diffractometer and measured using
CuKα monochromatic radiation at 100 K. The crystal of 4 was fixed on a
micro mount and placed on an Agilent Technologies Excalibur Eos
diffractometer and measured using monochromatic MoKα radiation at 170
K, since below 160 K the single crystal of 4 crashes into small pieces
(probably due to phase transition). The unit cell parameters (Table 1) were
refined by least square techniques. The structures have been solved by
the direct methods and refined using SHELXL–97 program[65] incorporated
in the OLEX2 program package.[66] The hydrogen atoms were placed in
the calculated positions and were included in the refinement in the ‘riding’
model approximation, with Uiso(H) set to 1.5Ueq(C) and C–H 0.96 Å for the
CH3 groups, Uiso(H) set to 1.2Ueq(C) and C–H 0.97 Å for the CH2 groups.
An empirical absorption correction was applied in the CrysAlisPro[67]
program complex using spherical harmonics, implemented in the SCALE3
ABSPACK scaling algorithm. The structures of 1-4 were deposited to
CCDC under codes 2009500-2009503.
Computational details. All computations have been carried out
using the Gaussian 16 program package[68] on the High-Performance
Computing cluster of St. Petersburg State University. The geometries of
the compounds have been fully optimized using three DFT methods with
subsequent vibrational analysis: the hybrid three-parameter exchange
functional of Becke[69] with the gradient corrected correlation functional of
Lee, Yang, and Parr[70] (B3LYP) with a split valence def2-SVP basis set,[71]
the dispersion corrected DFT method (B3LYP-D3)[72] with all electron def2-
TZVP basic set,[71] and M06-2X[73] functional with double the amount of
nonlocal exchange with all electron def2-TZVP basic set. For indium, a
quasi-relativistic effective core potential (ECP) basis set was used.[74] All
structures correspond to minima on the respective potential energy
surfaces (PES). As was recently demonstrated, for B(C6F5)3·Py complex
[8] A. G. Massey, A. J. Park, J. Organomet. Chem., 1964, 2,
245-250.
[9] J. L. W. Pohlmann, F. E. Brinckmann, Z. Naturforschung,
1965, 20b, 5-11.
[10] T. J. Marks Acc. Chem. Res., 1992, 25 , 57-65.
[11] X. Yang , C. L. Stern, T. J. Marks, J. Am. Chem. Soc.,
1994, 116, 10015-10031.
[12] W. E. Piers, T. Chivers, Chem. Soc. Rev. 1997, 26, 345-
354.
[13] W. E. Piers, Adv. Organomet. Chem. 2004, 52, 1-76.
[14] G. Erker, Dalton Trans. 2005, 1883-1890.
[15] C.H. Lee, S.J. Lee, J. W. Park, K. H. Kim, B. Y. Lee, J. S.
Oh, J. Molec. Catal. A: Chemical, 1998, 132, 231-239.
[16] M. Xu, J. Passart, A. E. Waked, J. Roy, W. Uhl, D. W.
Stephan, Phil. Trans. R. Soc., 2017, 375, 1-12.
[17] G. C. Welch, R. R. S. Juan, J. D. Masuda, D. W. Stephan,
Science, 2006, 314, 1124-1126.
[18] G. C. Welch, D. W. Stephan, J. Am. Chem. Soc., 2007,
129, 1880-1881.
[19] D. W. Stephan, G. Erker, Angew. Chem., Int. Ed. 2010, 49,
46-76.
[20] D. W. Stephan, G. Erker, Angew. Chem. Int. Ed., 2015, 54,
6400-6441.
[21] D. W. Stephan, Science 2016, 354, aaf7229.
[22] R. L. Melen, Chem. Commun. 2014, 50, 1161-1174.
[23] A. R. Jupp, D. W. Stephan, Trends in Chemistry, 2019, 1,
35-48.
6
This article is protected by copyright. All rights reserved.

10.1002/ejic.202000815
European Journal of Inorganic Chemistry
FULL PAPER
[24] U. Mayer, V. Gutmann, W. Gerger, Monatsh. Chem./Chem.
Mon., 1975, 106, 1235-1257.
[53] A.Y. Timoshkin, A.V. Suvorov, H.F. Bettinger, H.F.
Schaefer, J. Am. Chem. Soc. 1999, 121, 5676-5687.
[54] J. F. Deters, P. A. McCusker, R. C. Pilger, J. Am. Chem.
Soc., 1968, 90, 4583-4585.
[55] N. Walker, A. J. Leffler, Inorg. Chem., 1974, 13, 484-484.
[56] M. C. Hodgson, M. A. Khan, R. J. Wehmschulte, J. Cluster
Science, 2002, 13, 503-520.
[25] V. Gutmann, Coord. Chem. Rev., 1976, 18, 225-255.
[26] C. B. Caputo, L. J. Hounjet, R. Dobrovetsky, D. W.
Stephan, Science, 2013, 341, 1374-1377.
[27] H. Böhrer, N. Trapp, D. Himmel, M. Schleep, I. Krossing,
Dalton Trans., 2015, 44, 7489-7499.
[28] I. P. Romm, Yu. G. Noskov, A. A. Malkov, Russ. Chem.
Bull., Int. Ed., 2007, 56, 1935-1944.
[57] M. García-Castro, A. Martín, M. Mena, C. Yélamos, Chem.
Eur. J., 2009, 15, 7180-7191.
[29] R. D. Ernst, J. W. Freeman, L. Stahl, D. R. Wilson, A. M.
Arif, B. Nuber, M. L. Ziegler, J. Am. Chem. Soc. 1995, 117,
5075-5081.
[30] E. I. Davydova, A. V. Virovets, E. V. Peresypkina, I. V.
Kazakov, A. Y. Timoshkin, Russ. Chem. Bull., Int. Ed. 2020,
69, 84-90.
[31] a) E. I. Davydova, T. N. Sevastianova, A. V. Suvorov, A. Y.
Timoshkin, Coord. Chem. Rev. 2010, 254, 2031-2077; b) E.
I. Davydova, T. N. Sevastianova, A. Y. Timoshkin, Coord.
Chem. Rev. 2015, 297-298, 91-126.
[32] N. A. Shcherbina, A. V. Pomogaeva, A. S. Lisovenko, I. V.
Kazakov, N. Yu. Gugin, O. V. Khoroshilova, Y. V.
Kondrat’ev, A. Y. Timoshkin, Z. Anorg. Allg. Chem. 2020,
646, 873-881.
[58] I. Krossing, H. Nöth, S. Staude, Z. Naturforsch., B: Chem.
Sci., 2008, 63, 1045-1051.
[59] W. Ziemkowska, A. Sawicki, Main Group Metal Chem.,
2001, 24, 111-118.
[60] L. A. Mück, A. Y. Timoshkin, M. von Hopffgarten, G.
Frenking, J. Am. Chem. Soc. 2009, 131, 3942-3949.
[61] L. A. Mück, A. Y. Timoshkin, G. Frenking, Inorg. Chem.
2012, 51, 640-646.
[62] a) A. B. Saida, A. Chardon, A. Osi, N. Tumanov, J.
Wouters, A. I. Adjieufack, B. Champagne, G. Berionni,
Angew. Chem. Int. Ed. 2019, 58, 16889-16893; b) A.
Chardon, A. Osi, D. Mahaut, T.-H. Doan, N. Tumanov, J.
Wouters, L. Fusaro, B. Champagne, G. Berionni, Angew.
Chem. Int. Ed. 2020, 59, 12402-12406.
[33] L .J. Hounjet, C. Bannwarth, C. N. Garon, C. B. Caputo, S.
Grimme, D. W. Stephan, Angew. Chem. Int. Ed., 2013, 52,
7492-7495.
[63] Handbook of preparative inorganic chemistry, second
edition. Ed. G. Brauer, Academic Press, New York, 1963,
Vol. 1, 843, 858.
[34] C. Lorber, R. Choukroun, L. Vendier, Organometallics,
2008, 27, 5017-5024.
[35] M. Becker, A. Schulz, A. Villinger, K. Voss, RSC Advances
2011, 1, 128-134.
[36] J. Emsley, The Elements, Clarendon Press, Oxford, 1991,
251 p.
[37] V. Gutmann, The donor-acceptor approach to molecular
interactions, Plenum Press, New York, 1978, 279 p.
[38] M. Ullrich, A. J. Lough, D. W. Stephan, J. Am. Chem. Soc.,
2009, 131, 52-53.
[39] D.A. Atwood, A.H. Cowley, R.A. Jones, J. Coord. Chem.,
2009, 69-73.
[40] W. J. Evans, J. L. Shreeve, J. W. Ziller, Acta Cryst. C,
1996, C52, 2571-2573.
[41] T. Belgardt, J. Storre, H. W. Roesky, M. Noltemeyer, H. G.
Schmidt, Inorg. Chem. 1995, 34, 3821-3822.
[42] S. Krieck, H. Görls, M. Westerhausen, Organometallics,
2008, 27, 5052-5057.
[43] C.-R. Chen, H.-M. Gau, Acta Cryst. E, 2008, E64, m1381.
[44] S. Zhou, D.-W. Chuang, S.-J. Chang, H.-M. Gau,
Tetrahedron: Asymmetry, 2009, 20, 1407-1412.
[45] M. Barber, D. Liptak, J. P. Oliver, Organometallics, 1982, 1,
1307-1311.
[64] Yu. V. Kondrat’ev, A. V. Butlak, I. V. Kazakov, A. Y.
Timoshkin, Thermochim. Acta, 2015, 622, 64-71.
[65] G. M. Sheldrick, Acta Cryst., 2008, A64, 112.
[66] O. V. Dolomanov, L. J. Bourhis, R. J. Gildea, J. A. K.
Howard, H. Puschmann, J. Appl. Cryst., 2009, 42, 339-341.
[67] CrysAlisPro, Agilent Technologies, Version 1.171.36.20
±0.release 27-06-2012).
[68] M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria,
M. A. Robb, J. R. Cheeseman, G. Scalmani, V. Barone, G.
A. Petersson, H. Nakatsuji, X. Li, M. Caricato, A. V.
Marenich, J. Bloino, B. G. Janesko, R. Gomperts, B.
Mennucci, H. P. Hratchian, J. V. Ortiz, A. F. Izmaylov, J. L.
Sonnenberg, D. Williams-Young, F. Ding, F. Lipparini, F.
Egidi, J. Goings, B. Peng, A. Petrone, T. Henderson, D.
Ranasinghe, V. G. Zakrzewski, J. Gao, N. Rega, G. Zheng,
W. Liang, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J.
Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H.
Nakai, T. Vreven, K. Throssell, J. A. Montgomery, Jr., J. E.
Peralta, F. Ogliaro, M. J. Bearpark, J. J. Heyd, E.N.
Brothers, K. N. Kudin, V. N. Staroverov, T. A. Keith, R.
Kobayashi, J. Normand, K. Raghavachari, A. P. Rendell, J.
C. Burant, S. S. Iyengar, J. Tomasi, M. Cossi, J. M. Millam,
M. Klene, C. Adamo, R. Cammi, J. W. Ochterski, R. L.
Martin, K. Morokuma, O. Farkas, J. B. Foresman, D.J. Fox,
Gaussian 16, Revision A.03; Gaussian, Inc.: Wallingford,
CT, 2016.
[69] A. D. Becke, J. Chem. Phys. 1993, 98, 1372-1377.
[70] C. Lee, W. Yang, R. G. Parr, Phys. Rev. B, 1988, 37, 785-
789.
[71] F. Weigend, R. Ahlrichs, Phys. Chem. Chem. Phys., 2005,
7, 3297-3305.
[72] S. Grimme, S. Ehrlich, L. Goerigk, J. Comput. Chem., 2011,
32, 1456-1465.
[73] Y. Zhao, D. G. Truhlar, Theor. Chem. Acc., 2008, 120, 215-
241.
[46] V. Srini, J. De Me, J. P. Oliver, Organometallics, 1989, 8,
827-830.
[47] A. H. Cowley, C. L. B. Macdonald, J. S. Silverman, J. D.
Gorden, A. Voigt, Chem. Commun. 2001, 175-176.
[48] G. Rossetto, N. Brianese, A. Camporese, U. Casellato, F.
Ossola, M. Porchia, P. Zanella, R. Graziani, Gazz. Chim.
Ital., 1990, 120, 805.
[49] N. A. Shcherbina, I. V. Kazakov, N. Yu. Gugin, A. S.
Lisovenko, A. V. Pomogaeva, Yu. V. Kondrat’ev, V. V.
Suslonov, A. Y. Timoshkin, Rus. J. Gen. Chem., 2019, 89,
1162-1168.
[50] A. Y.Timoshkin, G. Frenking, Organomet. 2008, 27, 371-
380.
[51] X. Zhao, D. W. Stephan, Chem. Commun. 2011, 47, 1833-
1835.
[74] T. Leininger, A. Nicklass, W. Kuechle, H. Stoll, M. Dolg, A.
Bergner, Chem. Phys. Lett., 1996, 255, 274-280.
[52] M. El-Hamdi, M. Sol, J. Poater, A. Y. Timoshkin, J. Comp.
Chem., 2016, 37, 1355-1362.
7
This article is protected by copyright. All rights reserved.

10.1002/ejic.202000815
European Journal of Inorganic Chemistry
FULL PAPER
Entry for the Table of Contents
FULL PAPER
Structures, volatility and thermal
stability of E(C6F5)3 (E = B, Al, Ga, In)
complexes with diethyl ether were
Lewis acidity
I. V. Kazakov, A. S. Lisovenko, N. A.
Shcherbina, I.V. Kornyakov, N. Y.
Gugin, Y. V. Kondrat’ev, A. M.
Chernysheva, A. S. Zavgorodnii, A. Y.
Timoshkin*
studied
experimentally
and
computationally.
Large
reorganization energy hinders Lewis
acidity of boron-containing Lewis
acid.
Page No. – Page No.
Structural and energetic features of
group 13 element
trispentafluorophenyl complexes
with diethyl ether.
Additional Author information for the electronic version of the article.
Igor V. Kazakov:
ORCID https://orcid.org/0000-0003-1078-960X
Anna S. Lisovenko: ORCID: https://orcid.org/0000-0001-7443-0124
Nadezhda A. Shcherbina: ORCID https://orcid.org/0000-0002-1123-9717
Ilya V. Kornyakov: ORCID https://orcid.org/0000-0002-8904-6149
Nikita Y. Gugin:
ORCID: 0000-0002-7389-6528
Yurii V. Kondrat'ev: ORCID: https://orcid.org/0000-0002-5692-3037
Anna M. Chernysheva:
Artem S. Zavgorodnii:
ORCID: https://orcid.org/0000-0002-1894-4355
ORCID: https://orcid.org/0000-0002-1729-184X
Alexey Y.Timoshkin: ORCID:
http://orcid.org/0000-0002-1932-6647
8
This article is protected by copyright. All rights reserved.