Pentafluorophenyl Silver: Structure and Bonding of Arene Solvates

Article abstract of DOI:10.1021/acs.organomet.5b00492

The synthesis and full characterization of a series of AgC₆F₅·arene complexes (arene = RC₆H₅ with R = Me, Et; R₂C₆H₄, R₃C₆H₃, R₄C₆H₂, and R₅C₆H with R = Me) are presented. The structure and bonding are discussed on the basis of X-ray and theoretical studies with respect to the substitution pattern at the arene. Additionally, the structure of neat AgC₆F₅ and a facile way to generate crystals of pure AgC₆F₅ are reported. (Figure Presented).

Full text of DOI:10.1021/acs.organomet.5b00492

Article
pubs.acs.org/Organometallics
Pentafluorophenyl Silver: Structure and Bonding of Arene Solvates
Muhammad Farooq Ibad,† Axel Schulz,*,†,‡ and Alexander Villinger†
†Institut fur Chemie, Abteilung Anorganische Chemie, Universitat Rostock, Albert-Einstein-Strasse 3a, 18059 Rostock, Germany
̈
̈
‡Leibniz-Institut fur Katalyse e.V. an der Universitat Rostock, Albert-Einstein-Strasse 29a, 18059 Rostock, Germany
̈
̈
S
* Supporting Information
ABSTRACT: The synthesis and full characterization of a series of AgC6F5·arene
complexes (arene = RC6H5 with R = Me, Et; R2C6H4, R3C6H3, R4C6H2, and
R5C6H with R = Me) are presented. The structure and bonding are discussed on
the basis of X-ray and theoretical studies with respect to the substitution pattern at
the arene. Additionally, the structure of neat AgC6F5 and a facile way to generate
crystals of pure AgC6F5 are reported.
Scheme 2. Formal Catalytic Cycle with B(C6F5)3 as Catalyst
in the Generation of AgC6F5
INTRODUCTION
■
Pentafluorophenylsilver, AgC6F5, is a valuable starting material,
e.g., for the introduction of a C6F5 group.1−6 AgC6F5 was first
isolated by Miller and Sun in 1970, when they treated silver
trifluoroacetate, AgCF3COO, with pentafluorophenyl lithium,
LiC6F5 (Scheme 1).1,7−9 Alternatively, AgC6F5 was obtained
Scheme 1. Synthetic Routes to AgC6F5
shown that salt metathesis reaction of AgF and Li[B(C6F5)4] in
CH2Cl2 under ultrasonic irradiation yielded in situ neat
Ag[B(C6F5)4], which decomposed rapidly into AgC6F5 and
B(C6F5)3. The driving force of AgC6F5 formation is the
instability of the solvent-free Ag[B(C6F5)4] intermediate. If the
Ag+ ion is not stabilized by a donor solvent as in easily
accessible Ag[B(C6F5)4]·n toluene (n = 2, 3) or Ag[B(C6F5)4]·
nEt2O (n = 1−3), Ag+ is a very strong Lewis acid, resulting in
from the reaction of pentafluorophenyl bromide, C6F5Br, and
perfluoroisopropylsilver, Ag(CF3)2CF.1 Since acetonitrile was
used in all these reactions, either as solvent or for
recrystallization, it can be assumed that only the acetonitrile
solvate was finally isolated, as was shown later by Tyrra and our
group.3,5 Another elegant approach for isolating AgC6F5 is the
reaction of AgF with Me3Si(C6F5) again in donor solvents such
as nitriles (Scheme 1), however, with the disadvantage of
preparing Me3Si(C6F5) prior to that. Usually, AgC6F5 is isolated
as an 1:1 adduct from nitriles. These adducts lose their donor at
approximately 80−100 °C, and finally neat AgC6F5 decomposes
at 274 °C.3,5 As AgC6F5 dissolves only in polar solvents and is
usually obtained from reactions in polar solvents, the structure
of neat AgC6F5 is unknown. Already Tyrra speculated about the
structure in 2002: “... polymeric especially tetrameric units can
be assumed for donor-free AgC6F5.”3
the abstraction of C6F5 from the [B(C6F5)4]− ion, yielding
−
AgC6F5 and B(C6F5)3.5
The coordination chemistry of mono- and polynuclear
arylsilver(I) complexes of the type AgR (e.g., R = C6H5,
C6F5, C6Cl5, MeC6H4, Me2C6H3, (MeO)2C6H3), AgC6F5·L (L
= EtCN), and Ag2R2·L has been studied;8−16 however,
examples of structurally characterized organosilver(I) com-
plexes are still rare, appearing mostly as monomeric or
tetrameric species in the solid state.11,14−17 Diarylargentate
complexes form monomeric ion pairs,18 while [AgC6F5]·RCN
(R = Me, Et) is the first example exhibiting an infinite chain.3,5
Recently, we reported on a two-step formal B(C6F5)3-
catalyzed reaction generating neat AgC6F5 in weakly coordinat-
ing solvents such as CH2Cl2 as illustrated in Scheme 2. It was
Received: June 8, 2015
© XXXX American Chemical Society
A
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A similar structural motif was found for the mixed silver−gold
compound [Ag(C5H5N)3][Au(C6F5)2]·C5H5N.19
cooling to ambient temperatures over a period of 1 h resulted
in the deposition of colorless crystals or a precipitate (in the
case of benzene and toluene). Removal of excess arene by
decantation and drying in vacuo gave the corresponding
tetrakis(pentafluorophenylsilver) arene adduct, (AgC6F5)4·n
arene (n = 1, 2, or 4; arene = toluene, ethylbenzene, 1,2-
dimethylbenzene, 1,3-dimethylbenzene, 1,4-dimethylbenzene,
1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trimethyl-
benzene), as a colorless solid in good yields (40−80%). For the
tetra- and pentamethylbenzenes (arene = 1,2,3,5-tetramethyl-
benzene, 1,2,4,5-tetramethylbenzene, 1,2,3,4,5-pentamethylben-
zene), a slightly different procedure was applied. Neat AgC6F5
was also suspended and stirred in the corresponding arene,
however for 3 h at 60−80 °C, under reduced pressure (10−3
mbar). The mixture was slowly cooled to ambient temperature
over a period of 30 min. The resulting solid was filtered and
washed three times by repeated back distillation with n-hexane.
Interestingly, both synthetical protocols did not work for the
preparation of the arene adducts (AgC6F5)4·n arene (arene = n-
propyl benzene, isopropyl benzene, hexamethylbenzene). In all
these cases no adduct formation was observed since only the
starting material, pure AgC6F5, could be crystallized. To our
surprise, these reactions can be utilized to generate colorless
single crystals of AgC6F5 (40−80% yield) suitable for X-ray
elucidation (see below).
Herein we report the synthesis and full characterization of a
series of [AgC6F5]·arene complexes (arene = RC6H5 with R =
Me, Et; R2C6H4, R3C6H3, R4C6H2, and R5C6H with R = Me).
Additionally, we present the unprecedented solid-state
structure of AgC6F5 and a facile way to generate crystals of
neat AgC6F5.
RESULTS AND DISCUSSION
■
1. Synthesis. Neat AgC6F5. As illustrated in Scheme 2,5
solvent-free, pure AgC6F5 was obtained from Li[B(C6F5)4] and
AgF, which were first combined and suspended in dichloro-
methane prior to sonification in an ultrasonic bath at 40−60 °C
for 8 h. The resulting grayish suspension was filtered, resulting
in a clear, brownish solution. Removal of CH2Cl2 followed by
extraction of B(C6F5)3 by washing with n-hexane yielded an off-
white solid AgC6F5 (yield: 90%, Tdec = 276 °C). With pure
AgC6F5 in hand, we were able to study the solvation of AgC6F5
in differently substituted arenes (arene = benzene (b), toluene
(tol), ethylbenzene (eb), 1,2-dimethylbenzene (12dm), 1,3-
dimethylbenzene (13dm), 1,4-dimethylbenzene (14dm), 1,2,3-
trimethylbenzene (123tm), 1,2,4-trimethylbenzene (124tm),
1,3,5-trimethylbenzene (135tm), 1,2,3,5-tetramethylbenzene
(1235tem), 1,2,4,5-tetramethylbenzene (1245tem), 1,2,3,4,5-
pentamethylbenzene (12345 pm).
Once the crystalline material is isolated from the solvent, all
(AgC6F5)4·n arene adducts tend to easily lose solvent
molecules, which can be enhanced by drying under reduced
pressure. For this reason, all investigated materials were dried
to mass constancy to obtain correct elemental analysis data and
melting points or decomposition points. By this procedure,
(AgC6F5)4·2 arene (arene = benzene, toluene, ethylbenzene,
1,3-dimethylbenzene, 1,2,3,4,5-pentamethylbenzene) lose one
solvent molecule, or (AgC6F5)4·4 arene (arene = 1,2
dimethylbenzene, 1,2,4-trimethylbenzene) even lose two
solvent molecules. Solvent-free polymeric AgC6F5 decomposes
at 276 °C, while tetrameric (AgC6F5)4·n arene adducts melt
and/or decompose between 77 and 155 °C (see the SI), clearly
displaying a smaller thermal stability.
(AgC6F5)4·n arene. Neat pentafluorophenylsilver, AgC6F5,
was suspended in a minimum of the corresponding benzene
derivative (see above) at ambient temperatures (Scheme 3).
Scheme 3. Synthesis of Tetrameric (AgC6F5)4·narene
Solvates
The mixture was stirred for 30 min, followed by gently heating
to 80 °C, until a clear, colorless solution was obtained. Slow
Table 1. Selected NMR and Structural Data of (AgC6F5)4·arene Complexes (δ in ppm, d in Å) along with Computed Charges
a
(in e)
b
b
g
d
d
d
c
c
Δδ[1H]av
Δδ[13C]av
η(π)
ds(Ag−Carene
)
dav(Ag−Carene
)
dav(Ag−Ag)
qav(Ag)
Qct,arene
e
(AgC6F5)n
2.806
e
e
e
e
e
[Ag]4·2b
[Ag]4·2tol
[Ag]4·2eb
0.28
0.13
0.22
0.25
0.28
0.26
0.21
0.15
0.15
0.25
0.02
−0.01
0.16
0.3
0.1
0.3
0.3
0.6
0.3
0.3
0.3
0.3
0.3
0.2
0.0
0.0
2
2.934(5)
2.962(1)
2.665(2)
2.751(2)
2.946(2)
2.591(3)
2.76(1)
3.707
3.672
3.512
3.462
3.560
3.512
3.406
3.527
3.533
2.771
2.766
2.768
2.771
2.767
2.776
2.798
2.775
2.777
0.586
0.592
0.026
0.600
0.594
0.600
0.597
0.595
0.629
0.026
0.023
0.027
0.028
0.027
0.030
0.027
0.027
0.024
2, 3
3
[Ag]4·412dm
[Ag]4·213dm
[Ag]4·214dm
[Ag]4·4123tm
[Ag]4·2124tm (A)
[Ag]4·4124tm (B)
[Ag]4· 2135tm
[Ag]4·21235tem
[Ag]4·1245tem
3
2
2, 3
3
3
2.776(3)
2.746(2)
2
3
e
2.780(2)
e
3.503
e
2.788
e
0.600
e
0.039
e
f
[Ag]4·212345 pm
3
2.454(3)
3.177
2.761
0.622
0.029
a
b
[Ag]4 = (AgC6F5)4, dm = dimethyl, tm = trimethyl, tem = tetramethyl, pm = pentamethyl. Δδ = δ(neat arene) − δ(complex) in ppm, av = average
c
d
e
values, exact values are given in Table S19 of the SI. q and QCT in e. s = shortest, av = average, exact values in Tables S17 and S18. Crystalline
material was obtained, however not suitable for X-ray elucidation. n-Hexane solvate. η(π) = number of all d(Ag−Carene) < 3.5 Å (cf. ∑rvdW(Ag···C)
= 3.42 Å).
f
g
B
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1
Solution H and 13C NMR data revealed for (AgC6F5)4·n
are significantly shorter than the sum of van der Waals radii of
two silver atoms (cf. ∑rvdW(Ag···Ag) = 3.44 Å)23 and are
comparable to those found in other structurally characterized
Ag complexes.24 Commonly, arylsilver and perfluoroalkenylsil-
ver are tetrameric in the solid state, while diaryl argentates are
build up from separated ion pairs.21,22,25−39 With bridging C6F5
units, infinite chains were also observed in the unit cell of
AgC6F5·RCN (R = Me, Et),3,5 although most silver compounds
with a bridging aryl ligand prefer to form polynuclear
complexes. Interestingly, a molecular Ag4(C6F5)4 moiety with
a Ag4 zigzag chain (Ag−Ag distances: 2.7264(5), 3.0627(7) Å)
was observed by Fu and Zhu et al. embedded between two
germylene units.40 In contrast to AgC6F5, the lighter congener
base-free CuC6F5 forms a tetramer with bridging C6F5 moieties
and short Cu···Cu distances.41 Strong Ag···πarene as well as Ag···
Ag interactions have also been observed in a series of trinuclear
silver(I) complexes of fluorinated pyrazolates displaying
extended columnar structures.42−44 Trinuclear mercury com-
plexes with extensive πarene interactions are also known.45,46
Structure of (AgC6F5)4·n arene Adducts. With respect to the
space groups, number of formula units, and bonding situation
of the arene, there are no clear trends to be detected (see
Tables S17 and S18). However, in contrast to neat
arene (up to triple substitution at the arene) stable adducts
(with bound arenes) even in CD2Cl2 solution as illustrated by
the Δδ = δ(free arene) − δ(bound arene) values in Table 1
(see also Table S19), while for the 4- and 5-fold-substituted
arenes only very weak arene interactions were detected.
2. Structure and Bonding. Crystals suitable for X-ray
crystallographic analysis were obtained either directly from the
saturated solution of AgC6F5 dissolved in the corresponding
arene at low temperature (usually 5 °C) or by cooling a
saturated dichloromethane solution to 5 °C. In the case of
1,2,3,4,5-pentamethylbenzene, crystals suitable for X-ray
crystallographic analysis were obtained from the saturated
reaction solution after addition of n-hexane, leading to
(AgC6F5)4·2 (1,2,3,4,5-pentamethylbenzene) n-hexane solvate.
Astonishingly, when AgC6F5 was treated with 1,2,4-trimethyl-
benzene, depending on the crystallization conditions, either
crystals of (AgC6F5)4·4(1,2,4,-trimethylbenzene) or the dis-
olvate (AgC6F5)4·2(1,2,4-trimethylbenzene) could be obtained;
that is, formation of the disolvate is favored at higher
temperatures and concentration. All crystals were selected in
Fomblin YR-1800 perfluoroether at ambient temperature. The
samples were cooled to 173(2) K during measurement.
Structure of Neat AgC6F5. ∞{AgC6F5}20 crystallizes in the
1
1
∞{AgC6F5}, upon coordination of arene molecules, no one-
orthorhombic space group Cmcm with four formula units per
cell. Each Ag+ ion is surrounded by two bridging C6F5− ligands
with μ2-bound carbon atoms in a linear arrangement as
displayed by the C1−Ag1−C1′ angle of 180.0°, in contrast to
dimensional Ag−C zigzag chains are formed but in all cases
tetrameric (AgC6F5)4·n arene molecular units as depicted in
Figure 2. Interestingly, Ag+−Carene π-complexation47,48 of all
arene molecules is not observed in all cases. For example, in
(AgC6F5)4·2 toluene only one toluene molecule is bound to
one Ag+ center in a formal η2-coordination mode (Figure 2),
while the other one can be regarded as crystal solvent without
significantly interacting with Ag+ ions (all d(Ag−Carene) > 3.5
Å). A similar situation is found in (AgC6F5)4·2 arene (arene =
ethylbenzene and 1,4-dimethylbenzene, Figure 3). Since it is
rather difficult to give correct connectivities (hapticities) of
asymmetrically coordinated arenes, we have used the number of
d(Ag−Carene) < 3.5 Å contacts as criterion (cf. ∑rvdW(Ag···C) =
3.42 Å), leading to hapticity values ranging between 2 and 3
(Table 1).49 It seems to be interesting to have a look at the
trends of the shortest and average distances, ds(Ag···Carene) and
dav(Ag···Carene), respectively (Table 1). As can be derived from
these data, the larger the degree of substitution, the shorter the
ds(Ag···Carene) value, ranging from 2.45 (1,2,3,4,5-pentamethyl-
benzene) to 2.96 Å (ethylbenzene), and the average dav(Ag···
Carene) value is from 3.17 to 3.71 Å, respectively. Interestingly,
the average Ag···Ag distances, ranging between 2.76 and 2.79 Å
are not sensitive to the number of coordinated arenes nor the
degree of substitution, but they are significantly shortened
1
the situation found in ∞{AgC6F5·CH3CN} with alternating
bent (138.7°) and linear arrangements.3,5 As depicted in Figure
1, a one-dimensional infinite Ag−C zigzag chain21 is formed in
1
compared to the value of 2.806 Å in neat ∞{AgC6F5} (vide
supra).
Figure 1. Ag−C zigzag chains along the c-axis in the crystal of
1
∞{AgC6F5} (view along the a-axis). Selected distances in Å, angles in
As illustrated in Figures 2−4, there are different ways to
divide and classify the (AgC6F5)4·n arene adducts discussed
here: (i) With respect to the number of π-coordinated arene
molecules, we observed mono, double, and 4-fold adduct
formation. Interestingly, for 124tm we found double and 4-fold
adduct formation (species A and B, Figures 2 and 3, Table 1).
In the case of double adduct formation, the arene always forms
adduct bonds with opposite Ag+ ions of the tetrameric unit
(Ag1 and Ag3 complexation). (ii) The arene can feature one
donor−acceptor interaction to one Ag+ ion of one tetrameric
unit or can even act as a bridging ligand between two tetrameric
units, leading to (−Ag4−arene−Ag4−) chains in the crystal
(Figure 3). The latter is often the case when only one arene
deg: Ag1−C1 2.195(3), Ag1−C1′ 2.195(3), Ag1···Ag1′ 2.8058(2);
C1′−Ag1−C1 180.0(1), C1−Ag1−Ag1′ 129.72(6), Ag1′−Ag1−Ag1″
180.0, Ag1−C1′−Ag1′ 79.5(1).
the crystal along the c-axis with bent Ag−C−Ag′ (79.4°)
moieties and equal Ag−C bond lengths of 2.195(3) Å (cf.
2.147(2) and 2.128(5) Å in AgC6F5·RCN, R = Me, Et).3,5
Looking along the c-axis, all C6F5 rings are found eclipsed to
each other, and a straight chain of equidistantly arranged Ag+
ions with Ag···Ag distances of 2.8058(2) Å (cf. 2.89 Å in Ag
metal) is recognized. Hence, in addition to the Ag−C
coordination, as depicted in Figure 1, Ag···Ag (d10−d10)
interactions22 must be considered, as the Ag···Ag distances
C
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Figure 2. Molecular structures of (AgC6F5)4·n arene adducts with molecular units (Ag violet, C gray).
molecule acts as a donor solvent (arene = eb, 14dm) with
relatively small Ag···C distances (<3.42 Å). In these cases, the
second arene molecule always serves as crystal solvent species
with distances to the tetramer considerably larger than the sum
D
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(Figure 4). A planar Ag4C4 ring is formed for adducts of tol,
124tm (structure A) and 1235tem with planar Ag4 and C4
units, while for (AgC6F5)4·n arene (arene = eb, 13dm, 14dm,
and 135tm) it forms a folded C4 ring, whereas the Ag4 ring
remains planar. Finally, a puckered eight-membered Ag4C4 ring
is observed for arene = 12dm, 123tm, 124 (structure B), and
12345 pm. There seems to be no clear correlation between the
planarity/nonplanarity of the eight-membered ring and the
degree of substitution or the substitution pattern. Moreover,
the Ag4C4 eight-membered ring is highly flexible with respect to
the arrangement of the C6F5 rings, especially if van der Waals
interactions with arene molecules can be formed (vide infra,
Figures 4 and S2).
It should be noted that computations at the B3LYP/6-
31G(d,p)51 level of theory for (AgC6F5)4 (without arene
solvate molecules) display only the planar eight-membered ring
as a minimum structure at a very flat (with respect to
nonplanarity) potential energy surface. Thus, it can be assumed
that small changes in the environment of the tetrameric unit
can result in a large effect on the arrangement of the Ag4C4
heterocycle in accord with experimental observations.
Let us finally tackle the question of why upon coordination
1
of arene molecules in ∞{AgC6F5} the one-dimensional Ag−C
zigzag chains are transformed into tetrameric (AgC6F5)4·n
arene molecular units. Obviously, lots of weak interactions of
the arenes with the AgC6F5 moieties favor the formation of
tetramers rather than chains. A closer look at these weak
interactions revealed a large number of different types of van
der Waals interactions: (i) Ag+−Carene π-complexation, (ii) π-
Figure 3. Molecular structures of (AgC6F5)4·n arene adducts with one-
dimensional (−Ag4−arene−Ag4−) chains in the crystals (Ag violet, C
gray).
−
stacking between C6F5 and the arene (parallel displaced and
T-shaped arrangements),47,52−54 and (iii) F···Harene hydrogen
bonding (Figure 5). For example, the electrostatic potential
(ESP) mapped onto the electron density of (AgC6F5)4·toluene
nicely illustrates the electrostatically favorable arrangement of
one toluene molecule allowing strong van der Waals interaction
between one Ag+ center and Ctoluene centers (shortest Ag···C
2.934 Å). Additionally, two types of rather weak F···H
hydrogen bonds might be discussed between F atoms of the
of the van der Waals radii (cf. ∑rvdW(Ag···C) = 3.42 Å). It
should be noted that these solvent molecules are easily released,
e.g., under reduced pressure or with time outside the solvent
under normal pressure. Such (−M4−arene−M4−) chains have
also been observed by Jakle et al. for the lighter congener
̈
copper with arenes such as naphthalene or 2,2′-bithiophene
displaying Cu···πarene and Cu···S interactions.50 (iii) The most
prominent structural motif is the eight-membered Ag4C4
heterocycle of the tetrameric unit (Figures 2−4), which,
however, can feature three different structural modifications
with respect to the planarity of the Ag4 and/or C4 moiety
−
C6F5 ion and protons of the methyl group (F···Hmethyl,toluene
2.85 Å) and protons of the aryl ring (F···Haryl,toluene 2.78 Å). In
the latter case, protons of the toluene species can interact with
Figure 4. Molecular structures of Ag4 and C4 moieties within an eight-membered Ag4C4 ring in (AgC6F5)4·n arene adducts (Ag violet, C gray).
E
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In agreement with these weak interactions, the computed
charge transfer from the arenes to the silver centers is rather
small, with 0.02−0.04e per arene molecule according to
NBO58−60 analysis (NBO = natural bond analysis, Table 1).
Hence, these interactions can be considered purely electrostatic
in nature. The computed partial charges of the formal Ag+ ions
amount to +0.59 to +0.63e, indicating some covalency between
−
the formal Ag+ and C6F5 ions. Actually, NBO analysis finds
highly polar Ag−CC6F5 bonds, which, however, are almost 90%
localized at the carbon center.
3. CONCLUSION
The isolation of crystalline AgC6F5 was achieved by
recrystallization of amorphous AgC6F5 from arenes with
bulky substituents or a high degree of substitution at the
arene. The solid-state structure revealed Ag−C zigzag chains
along the c-axis in the crystal. Hence crystalline AgC6F5 should
Figure 5. Computed charge density isosurface plot for X-ray structural
data of (AgC6F5)4·2 toluene (one toluene solvate molecule omitted for
clarity). The isosurface has been colored according to the electrostatic
potential (red: most negative regions; blue: most positive regions).
1
be better denoted as polymeric ∞{AgC6F5}. With less bulky
arene 1∞{AgC6F5} forms a series of different types of tetrameric
(AgC6F5)4·n arene adducts (n = 1, 2, 4). Molecular tetrameric
(AgC6F5)4 units are favored over a chain-like structure as found
−
fluorine atoms of two adjacent C6F5 rings, since the toluene
lies parallelly displaced55 to one and almost perpendicular (T-
shaped)56 to the second C6F5 ring with one C−Haryl,toluene
−
1
in neat ∞{AgC6F5} due to a multitude of Ag−C π-
bond pointing directly to the perpendicular C6F5− ring center.57
These are known arrangements discussed in cases of π-stacking
interactions. A second example is as follows: For the chain-like
(−Ag4−arene−Ag4−) units in (AgC6F5)4·n arene species
(arene = eb, 1.2dm, Figure 3) the pocket formed by the two
Ag4C4 units generates exactly the space needed to host one
arene molecule (Figure 6). In the case of the (AgC6F5·arene)4
complexation, π-stacking, and F···H hydrogen bond inter-
actions. Furthermore, it should be stressed that different
structures from the ones reported may form under other
crystallization conditions, for example when using non-
coordinating solvents with different amounts of the arenes
present.
EXPERIMENTAL SECTION
■
General Information. All manipulations were carried out under
oxygen- and moisture-free conditions under argon using standard
Schlenk or drybox techniques. Note: Since (AgC6F5)4·n arene adducts
are highly labile solvates, it is simply impossible to obtain more
accurate elemental analysis (EA). These are highly labile species that
easily lose their solvent molecules even under standard conditions. So
whenever these species are removed from the mother liquor, the
substance releases solvent, which was not taken into account in the
EA.
General Procedure for the Synthesis of Tetrakis-
(pentafluorophenylsilver) Arene Adducts (AgC6F5)4·n arene.
Procedure 1. Arene = benzene, toluene, ethylbenzene, 1,2-
dimethylbenzene, 1,3-dimethylbenzene, 1,4-dimethylbenzene, 1,2,3-
trimethylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene,
1,2,3,5-tetramethylbenzene. Neat pentafluorophenylsilver AgC6F5
(0.100 g, 0.36 mmol) was suspended in a minimum of the
corresponding arene (3−5 mL) at ambient temperatures. The mixture
was stirred for 30 min, followed by gently heating to 60 °C, until a
clear, colorless solution was obtained. Slow cooling to ambient
temperature over a period of 1 h resulted in the deposition of colorless
crystals or a precipitate (in the case of benzene and toluene). Removal
of excess arene by decantation and drying in vacuo gave the
corresponding tetrakis(pentafluorophenylsilver) arene adduct
(AgC6F5)4·n arene (n = 1, 2; arene = toluene, ethylbenzene, 1,2-
dimethylbenzene, 1,3-dimethylbenzene, 1,4-dimethylbenzene, 1,2,3-
trimethylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene) as
a colorless solid in good yields (40−80%).
Procedure 2. Arene = 1,2,3,5-tetramethylbenzene, 1,2,4,5-tetrame-
thylbenzene, 1,2,3,4,5-pentamethylbenzene. Neat pentafluorophenyl-
silver, AgC6F5 (0.100 g, 0.36 mmol), was suspended and stirred in the
corresponding arene (about 5 g) for 3 h at 60−80 °C, at a reduced
pressure of 1−3 mbar. The mixture was slowly cooled to ambient
temperature over a period of 30 min. The resulting solid was separated
by filtration (F4) and washed three times by repeated back distillation
with n-hexane. Drying in vacuo with gentle heating gave the
corresponding tetrakis(pentafluorophenylsilver) arene adduct
Figure 6. ESP plotted onto a charge density isosurface for X-ray
structural data of a section of the chainlike structure in the crystal
structure of (AgC6F5)4·2 1,4-dimethylbenzene (one solvate molecule
omitted for clarity). Shown is one pocket between two Ag4C4 units
hosting one 1,4-dimethylbenzene.
species, the ESPs nicely illustrate solvated Ag4C4 units leading
to ball-shaped moieties with all F atoms and the methyl groups
at the surface of these balls, as depicted in Figure S3. So
depending on the energy gain by all above-discussed small
interactions (Figure 5), pocket formation in chain-like
structures (utilizing one molecule) of formal monoadducts or
double/4-fold adduct formation within one molecular tetra-
meric Ag4C4 unit is favored (Figure S3). In summary, it can be
assumed that Ag−C π-complexation,47 π-stacking52 between
−
the arene and C6F5 rings, and weak F···H hydrogen bond
interactions, which are observed in all considered, structurally
highly flexible arene adducts (see Figure S3), considerably
stabilize the four-membered ring system rather than allowing a
1
chain-like structure as found in neat ∞{AgC6F5}.
F
DOI: 10.1021/acs.organomet.5b00492
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
(AgC6F5)4·n arene (1,2,3,5-tetramethylbenzene, 1,2,4,5-tetramethyl-
benzene) as a colorless solid in good yields (40−80%). In the case of
1,2,3,4,5-pentamethylbenzene, the filtrate (instead of the residue) was
used to obtain crystals of the corresponding tetrakis-
(pentafluorophenylsilver) arene adduct (AgC6F5)4·n arene (yield:
15−20%, see below).
C), 125.7 (s, 2CH, 1,2-dimethylbenzene), 130.0 (s, 2CH, 1,2-
dimethylbenzene), 137.6 (s, 2C, 1,2-dimethylbenzene), 137.7 (dm, m-
CF, 1J(13C−19F) = 259 Hz), 144.9 (dm, p-CF, 1J(13C−19F) = 259 Hz),
1
153.8 (dm, o-CF, J(13C−19F) = 234 Hz). 19F{1H} NMR (25 °C,
CD2Cl2, 282.4 MHz): δ = −158.2 (m, m-CF, 1J(13C−19F) = 259 Hz),
−144.1 (dm, p-CF, 1J(13C−19F) = 259 Hz), −100.4 (dm, o-CF,
1J(13C−19F) = 234 Hz). IR (ATR, 16 scans): 2930 (w), 2861 (w),
1631 (m), 1602 (w), 1554 (w), 1536 (w), 1502 (s), 1447 (s), 1432
(s), 1387 (m), 1377 (m), 1338 (m), 1259 (m), 1187 (w), 1159 (w),
1132 (w), 1118 (w), 1073 (m), 1057 (s), 1022 (w), 954 (s), 870 (w),
760 (m), 746 (m), 716 (w), 664 (w), 595 (m), 581 (w). MS (CI+,
isobutane): 1101 [(AgC6F5)4 + H]+, 937, 936, 935 933
[Ag4isotopic(C6F5)3 + H]+, 383, 382, 381 [AgC6F5·C8H10 + H]+, 382,
381, 380 [AgC6F5·C8H10]+, 109, 107 [Agisotopic]+, 107 [C8H10 + H]+.
Crystals suitable for X-ray crystallographic analysis were obtained
directly from the above reaction solution.
(AgC6F5)4·2 benzene. Mp: 154.60 °C, 223.33 °C (dec). Anal. Calcd
1
for (AgC6F5)4·C6H6, % (found): C 30.59 (29.02); H 0.51 (1.06). H
NMR (25 °C, CD2Cl2, 300.13 MHz): δ = 7.35 (s, 6H, ArCH).
13C{1H} NMR (25 °C, CD2Cl2, 75.47 MHz): δ = 102.0 (br, ipso-C),
1
128.9 (s, 6CH, benzene), 137.7 (dm, m-CF, J(13C−19F) = 259 Hz),
144.7 (dm, p-CF, 1J(13C−19F) = 259 Hz), 153.8 (dm, o-CF,
1J(13C−19F) = 236 Hz). 19F{1H} NMR (25 °C, CD2Cl2, 282.4
MHz): δ = −158.2 (m, m-CF, 1J(13C−19F) = 259 Hz), −144.1 (dm, p-
1
1
CF, J(13C−19F) = 259 Hz), −100.4 (dm, o-CF, J(13C−19F) = 236
Hz). IR (ATR, 16 scans): 1631 (m), 1602 (w), 1557 (w), 1537 (w),
1504 (s), 1463 (w), 1440 (s), 1427 (s), 1379 (m), 1333 (m), 1265
(m), 1131 (w), 1110 (w), 1073 (m), 1056 (s), 1009 (w), 980 (w), 949
(s), 769 (w), 747 (m), 717 (w), 687 (m), 662 (w), 597 (m). MS (CI+,
isobutane): 1101 [Ag4(C6F5)4 + H]+, 1100 [Ag4(C6F5)4]+, 353
(AgC6F5)4·2 (1,3-dimethylbenzene). Mp: 85.59 °C (dec). Anal.
Calcd for (AgC6F5)4·C8H10, % (found): C 31.87 (31.53); H 0.84
1
(1.22). H NMR (25 °C, CD2Cl2, 300.13 MHz): δ = 2.29 (s, 6H,
ArCH3), 6.93−7.04 (m, 3H, ArCH), 7.08−7.13 (m, 1H, ArCH).
13C{1H} NMR (25 °C, CD2Cl2, 75.47 MHz): δ = 21.6 (s, CH3, 1,3-
dimethylbenzene), 101.2 (br, ipso-C), 126.4 (s, CH, 1,3-dimethylben-
zene), 128.4 (s, CH, 1,3-dimethylbenzene), 130.4 (s, 2CH, 1,3-
dimethylbenzene), 138.5 (dm, m-CF, 1J(13C−19F) = 258 Hz), 138.5 (s,
[AgC6F5·C6H6 + H]+, 335 [C6F5 − C6F5 + H]+, 334 [C6F5
−
C6F5]+, 224 [C6F5 − C4H9]+, 206 [C6F5 − C3H3]+, 117 [C6H6 +
C3H3]+, 79 [C6H6 + H]+.
(AgC6F5)4·2 toluene. Mp: 124.43 °C. Anal. Calcd for (AgC6F5)4·
1
1
2C, 1,3-dimethylbenzene), 144.8 (dm, p-CF, J(13C−19F) = 258 Hz),
C7H8, % (found): C 31.24 (30.08); H 0.68 (0.88). H NMR (25 °C,
1
153.7 (dm, o-CF, J(13C−19F) = 234 Hz). 19F{1H} NMR (25 °C,
CD2Cl2, 300.13 MHz): δ = 2.33 (s, 3H, ArCH3), 7.10−7.26 (m, 5H,
ArCH). 13C{1H} NMR (25 °C, CD2Cl2, 75.47 MHz): δ = 21.7 (s,
CH3, toluene), 102.8 (br, ipso-C), 125.7 (s, CH, toluene), 128.7 (s,
2CH, toluene), 129.6 (s, 2CH, toluene), 137.6 (dm, m-CF,
1J(13C−19F) = 259 Hz), 138.6 (s, C, toluene), 144.8 (dm, p-CF,
CD2Cl2, 282.4 MHz): δ = −158.2 (m, m-CF, 1J(13C−19F) = 258 Hz),
−144.1 (dm, p-CF, 1J(13C−19F) = 258 Hz), −100.4 (dm, o-CF,
1J(13C−19F) = 234 Hz). IR (ATR, 16 scans): 1631 (m), 1603 (w),
1586 (w), 1562 (w), 1557 (w), 1538 (w), 1504 (s), 1469 (w), 1441
(s), 1427 (s), 1379 (m), 1333 (m), 1265 (m), 1195 (w), 1131 (w),
1112 (w), 1073 (s), 1056 (s), 1007 (w), 982 (w), 949 (s), 740 (m),
718 (m), 697 (m), 661 (w), 620 (w), 596 (m), 542 (w). MS (CI+,
1
1J(13C−19F) = 259 Hz), 153.8 (dm, o-CF, J(13C−19F) = 236 Hz).
19F{1H} NMR (25 °C, CD2Cl2, 282.4 MHz): δ = −158.2 (m, m-CF,
1
1J(13C−19F) = 259 Hz), −144.1 (dm, p-CF, J(13C−19F) = 259 Hz),
isobutane): 1100 [Ag4(C6F5)4]+, 933 [Ag4(C6F5)3]+, 334 [C6F5
−
−100.4 (dm, o-CF, 1J(13C−19F) = 236 Hz). IR (ATR, 16 scans): 1631
(m), 1603 (w), 1586 (w), 1562 (w), 1557 (w), 1538 (w), 1504 (s),
1469 (w), 1441 (s), 1427 (s), 1379 (m), 1333 (m), 1265 (m), 1195
(w), 1131 (w), 1112 (w), 1073 (s), 1056 (s), 1007 (w), 982 (w), 949
(s), 740 (m), 718 (m), 697 (m), 661 (w), 620 (w), 596 (m), 542 (w).
MS (CI+, isobutane): 1101 [Ag4(C6F5)4 + H]+, 353 [AgC6F5·C6H6 +
H]+, 335 [C6F5 − C6F5 + H]+, 334 [C6F5 − C6F5]+, 224 [C6F5 −
C4H9]+, 206 [C6F5 − C3H3]+, 135 [C7H8 + C3H7]+, 93 [C7H8 + H]+.
Crystals suitable for X-ray crystallographic analysis were obtained by
cooling a saturated dichloromethane solution to 5 °C.
C6F5]+, 223 [C6F5 − C4H8]+, 168 [C6F5 − H]+, 147 [C8H10 + C3H5],
107 [Ag]+, 107 [C8H10 + H]+, 106 [C8H10]+, 91 [C7H7]+. Crystals
suitable for X-ray crystallographic analysis were obtained directly from
the above reaction solution by storage at 5 °C.
(AgC6F5)4·2 (1,4-dimethylbenzene). Mp: 109.17 °C (dec). Anal.
Calcd for (AgC6F5)4·2 C8H10, % (found): C36.62 (36.95); H 1.54
1
(1.81). H NMR (25 °C, CD2Cl2, 300.13 MHz): δ = 2.29 (s, 6H,
ArCH3), 7.05 (s, 4H, ArCH). 13C{1H} NMR (25 °C, CD2Cl2, 62.89
MHz): δ = 21.0 (s, 2CH3, 1,4-dimethylbenzene), 101.9 (br, ipso-C),
129.1 (s, 4CH, 1,4-dimethylbenzene), 135.6 (s, 2C, 1,4-dimethylben-
(AgC6F5)4·2 ethylbenzene. Mp: 77.20 °C (dec). Anal. Calcd for
1
zene), 137.7 (dm, m-CF, J(13C−19F) = 259 Hz), 144.8 (dm, p-CF,
1
(AgC6F5)4 · C8H10, % (found): C 31.87 (28.24); H 0.84 (0.77). H
1
1J(13C−19F) = 259 Hz), 153.8 (dm, o-CF, J(13C−19F) = 234 Hz).
NMR (25 °C, CD2Cl2, 300.13 MHz): δ = 1.21 (t, 3H, CH3, 3J
(1H−1H) = 7.6 Hz), 2.63 (q, 2H, CH2, 3J (1H−1H) = 7.6 Hz), 7.11−
7.30 (m, 5H, ArCH). 13C{1H} NMR (25 °C, CD2Cl2, 75.47 MHz): δ
= 16.0 (s, CH3, ethylbenzene), 29.4 (s, CH2, ethylbenzene), 102.8 (br,
ipso-C), 126.0 (s, CH, ethylbenzene), 128.4 (s, 2CH, ethylbenzene),
19F{1H} NMR (25 °C, CD2Cl2, 282.4 MHz): δ = −158.2 (m, m-CF,
1
1J(13C−19F) = 259 Hz), −144.1 (dm, p-CF, J(13C−19F) = 259 Hz),
−100.4 (dm, o-CF, 1J(13C−19F) = 234 Hz). IR (ATR, 16 scans): 2929
(w), 2873 (w), 1650 (w), 1644 (m), 1631 (m), 1603 (w), 1557 (w),
1502 (s), 1447 (s), 1435 (s), 1383 (s), 1375 (s), 1338 (s), 1299 (w),
1262 (m), 1226 (m), 1198 (w), 1180 (w), 1075 (s), 1057 (s), 977 (s),
956 (s), 900 (m), 860 (w), 812 (m), 791 (m), 774 (m), 755 (m), 748
(m), 726 (w), 717 (w), 683 (m), 661 (m), 644 (w), 610 (w), 597 (m),
573 (m), 540 (w). MS (CI+, isobutane): 1100 [Ag4(C6F5)4]+, 933
[Ag4(C6F5)3]+, 334 [C6F5 − C6F5]+, 223 [C6F5 − C4H8]+, 168 [C6F5
− H]+, 147 [C8H10 + C3H5], 107 [Ag]+, 107 [C8H10 + H]+, 106
[C8H10]+, 91 [C7H7]+. Crystals suitable for X-ray crystallographic
analysis were obtained directly from the above reaction solution.
(AgC6F5)4·4 (1,2,3-trimethylbenzene). Mp: 123 °C (dec). Anal.
Calcd for (AgC6F5)4·2.5 C9H12, % (found): C 39.89 (38.46); H 2.16
1
128.8 (s, 2CH, ethylbenzene), 137.6 (dm, m-CF, J(13C−19F) = 259
1
Hz), 145 (s, C, ethylbenzene), 144.8 (dm, p-CF, J(13C−19F) = 259
Hz), 153.6 (dm, o-CF, 1J(13C−19F) = 234 Hz). 19F{1H} NMR (25 °C,
CD2Cl2, 282.4 MHz): δ = −158.2 (m, m-CF, 1J(13C−19F) = 259 Hz),
−144.1 (dm, p-CF, 1J(13C−19F) = 259 Hz), −100.4 (dm, o-CF,
1J(13C−19F) = 234 Hz). IR (ATR, 16 scans): 1630 (m), 1604 (w),
1583 (w), 1557 (w), 1537 (w), 1501 (s), 1447 (s), 1434 (s), 1380
(m), 1341 (m), 1307 (m), 1258 (s), 1232 (s), 1201 (m), 1149 (m),
1133 (m), 1072 (s), 1055 (s), 998 (w), 982 (m), 954 (s), 908 (w), 808
(w), 790 (w), 775 (w), 748 (m), 718 (w), 684 (w), 661 (w), 640 (w),
597 (m), 554 (w). MS (CI+, isobutane): 335 [C6F5 − C6F5 + H]+, 334
[C6F5 − C6F5]+, 168 [C6F5H]+, 119 [C9H11]+. Crystals suitable for X-
ray crystallographic analysis were obtained directly from the above
reaction solution.
1
(2.45). H NMR (25 °C, CD2Cl2, 300.13 MHz): δ = 2.17 (s, 3H,
ArCH3), 2.27 (s, 6H, ArCH3), 6.97−7.89 (m, 3H, ArCH). 13C{1H}
NMR (25 °C, CD2Cl2, 75.47 MHz): δ = 15.6 (s, CH3, 1,2,3-
trimethylbenzene), 20.8 (s, 2CH3, 1,2,3-trimethylbenzene), 101.7 (br,
ipso-C), 124.7 (s, CH, 1,2,3-trimethylbenzene), 127.6 (s, 2CH, 1,2,3-
trimethylbenzene), 136.1 (s, C, 1,2,3-trimethylbenzene), 137.3 (s, 2C,
(AgC6F5)4·4 (1,2-dimethylbenzene). Mp: 89.5 °C (dec). Anal.
Calcd for (AgC6F5)4·2C8H10, % (found): C 36.62 (36.23); H 1.54
1
(1.58). H NMR (25 °C, CD2Cl2, 250.13 MHz): δ = 2.25 (s, 6H,
ArCH3), 7.03−7.14 (m, 4H, ArCH). 13C{1H} NMR (25 °C, CD2Cl2,
125.75 MHz): δ = 20.0 (s, 2CH3, 1,2-dimethylbenzene), 101.9 (br, ipso-
1,2,3-trimethylbenzene), 137.7 (dm, m-CF, J(13C−19F) = 258 Hz),
1
144.8 (dm, p-CF, 1J(13C−19F) = 258 Hz), 153.8 (dm, o-CF,
G
DOI: 10.1021/acs.organomet.5b00492
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
1J(13C−19F) = 234 Hz). 19F{1H} NMR (25 °C, CD2Cl2, 282.4 MHz):
benzene), 21.1 (s, CH3, 1,2,3,5-tetramethylbenzene), 102.0 (br, ipso-
C), 127.9 (s, 2CH, 1,2,3,5-tetramethylbenzene), 132.8 (s, C, 1,2,3,5-
tetramethylbenzene), 135.0 (s, C, 1,2,3,5-tetramethylbenzene), 137.2
1
δ = −158.2 (m, m-CF, J(13C−19F) = 258 Hz), −144.1 (dm, p-CF,
1J(13C−19F) = 258 Hz), −100.4 (dm, o-CF, 1J(13C−19F) = 234 Hz). IR
(ATR, 16 scans): 1630 (m), 1603 (w), 1574 (w), 1556 (w), 1537 (w),
1532 (w), 1503 (s), 1499 (s), 1444 (s), 1429 (s), 1383 (m), 1373 (m),
1338 (m), 1373 (m), 1338 (m), 1331 (m), 1262 (m), 1253 (m), 1185
(w), 1161 (w), 1127 (m), 1110 (m), 1085 (m), 1070 (m), 1053 (s),
999 (w), 980 (m), 953 (s), 894 (m), 789 (s), 757 (m), 739 (m), 710
(m), 684 (m), 660 (m), 611 (w), 590 (m), 532 (w). MS (CI+,
1
(s, 2C, 1,2,3,5-tetramethylbenzene), 137.4 (dm, m-CF, J(13C−19F) =
1
259 Hz), 144.8 (dm, p-CF, J(13C−19F) = 259 Hz), 153.7 (dm, o-CF,
1J(13C−19F) = 234 Hz). 19F{1H} NMR (25 °C, CD2Cl2, 282.4 MHz):
−158.2 (m, m-CF, 1J(13C−19F) = 259 Hz), −144.1 (dm, p-CF,
1
1J(13C−19F) = 259 Hz), −100.4 (dm, o-CF, J(13C−19F) = 234 Hz).
19F{1H} NMR (25 °C, C6D6, 282.4 MHz): δ = −158.2 (m, m-CF,
isobutane): 1100 [Ag4(C6F5)4]+, 933 [Ag4(C6F5)3]+, 334 [C6F5
−
1
1J(13C−19F) = 259 Hz), −144.1 (dm, p-CF, J(13C−19F) = 259 Hz),
C6F5]+, 223 [C6F5 − C4H8]+, 135 [C10H14 + H], 133 [C10H13]+, 121
[C9H12 + H]+, 120 [C9H12]+, 119 [C9H11]+, 105 [C8H9]+. Crystals
suitable for X-ray crystallographic analysis were obtained from a
saturated solution of dichloromethane and 1,2,3-trimethylbenzene.
(AgC6F5)4·2 (1,2,4-trimethylbenzene). Mp: 103.15 °C (dec). Anal.
Calcd for (AgC6F5)4·2C9H12, % (found): C 37.64 (37.76); H 1.81
−100.4 (dm, o-CF, 1J(13C−19F) = 234 Hz). IR (ATR, 16 scans): 2953
(w), 2925 (w), 2861(w), 1644 (w), 1634 (m), 1601 (w), 1557 (w),
1510 (m), 1505 (m), 1462 (s), 1450 (s), 1379 (m), 1338 (m), 1275
(m), 1260 (m), 1083 (s), 1056 (m), 977 (s), 955 (s), 891 (w), 862
(m), 797 (w), 775 (w), 768 (w), 755 (m), 746 (w), 726 (w), 709 (w),
684 (m), 660 (m), 610 (w), 602 (w), 573 (m), 555 (w), 522 (w), 475
(w), 448 (w), 426 (w), 408 (w). MS (CI+, isobutane): 334 [C6F5 −
C6F5]+, 223 [C6F5 − C4H8]+, 135 [C10H14 + H], 134 [C10H14]+, 133
[C10H13]+. Crystals suitable for X-ray crystallographic analysis were
obtained from a saturated solution of dichloromethane and 1,2,3,5-
tetramethylbenzene.
1
(1.80). H NMR (25 °C, CD2Cl2, 250.13 MHz): δ = 2.20 (s, 3H,
3
ArCH3), 2.24 (s, 3H, ArCH3), 2.25 (s, 3H, ArCH3), 6.86 (d, 1H, J
(1H−1H) = 7.7 Hz, ArCH), 6.96 (s, 1H, ArCH), 6.98 (d, 1H, J
3
(1H−1H) = 7.7 Hz, ArCH). 13C{1H} NMR (25 °C, CD2Cl2, 62.89
MHz): δ = 19.5 (s, CH3, 1,2,4-trimethylbenzene), 19.9 (s, CH3, 1,2,4-
trimethylbenzene), 21.1 (s, CH3, 1,2,4-trimethylbenzene), 102.0 (br,
ipso-C), 126.1 (s, CH, 1,2,4-trimethylbenzene), 129.3 (s, CH, 1,2,4-
trimethylbenzene), 130.9 (s, CH, 1,2,4-trimethylbenzene), 134.1 (s, C,
1,2,4-trimethylbenzene), 135.9 (s, C, 1,2,4-trimethylbenzene), 137.2
(AgC6F5)4·1,2,4,5-tetramethylbenzene. Mp: 105.89 °C (dec). Anal.
Calcd for (AgC6F5)4·0.5C10H14, % (found): C 29.85 (30.39); H 0.60
1
(0.46). H NMR (25 °C, CD2Cl2, 300.13 MHz): δ = 2.19 (s, 12H,
4ArCH3), 6.91 (s, 2H, 2ArCH). 13C{1H} NMR (25 °C, CD2Cl2, 62.89
MHz): δ = 19.46 (s, 4CH3, 1,2,4,5-tetramethylbenzene), 102.0 (br,
ipso-C), 130.3 (s, 2CH, 1,2,4,5-tetramethylbenzene), 134.7 (s, 4C,
1,2,4,5-tetramethylbenzene), 137.7 (dm, m-CF, 1J(13C−19F) = 259
Hz), 144.8 (dm, p-CF, 1J(13C−19F) = 259 Hz), 153.2 (dm, o-CF,
1J(13C−19F) = 234 Hz). 19F{1H} NMR (25 °C, CD2Cl2, 282.4 MHz):
1
(s, C, 1,2,4-trimethylbenzene), 137.4 (dm, m-CF, J(13C−19F) = 259
Hz), 144.8 (dm, p-CF, 1J(13C−19F) = 259 Hz), 153.7 (dm, o-CF,
1J(13C−19F) = 234 Hz). 19F{1H} NMR (25 °C, CD2Cl2, 282.4 MHz):
1
δ = −158.2 (m, m-CF, J(13C−19F) = 259 Hz), −144.1 (dm, p-CF,
1
1J(13C−19F) = 259 Hz), −100.4 (dm, o-CF, J(13C−19F) = 234 Hz).
19F{1H} NMR (25 °C, C6D6, 282.4 MHz): δ = −157.6 (m, m-CF,
1
δ = −158.2 (m, m-CF, J(13C−19F) = 259 Hz), −144.1 (dm, p-CF,
1
1J(13C−19F) = 259 Hz), −145.1 (dm, p-CF, J(13C−19F) = 259 Hz),
1J(13C−19F) = 259 Hz), −100.4 (dm, o-CF, 1J(13C−19F) = 234 Hz). IR
(ATR, 16 scans): 2953 (w), 2925 (w), 2861(w), 1644 (w), 1634 (m),
1601 (w), 1557 (w), 1510 (m), 1505 (m), 1462 (s), 1450 (s), 1379
(m), 1338 (m), 1275 (m), 1260 (m), 1083 (s), 1056 (m), 977 (s), 955
(s), 891 (w), 862 (m), 797 (w), 775 (w), 768 (w), 755 (m), 746 (w),
726 (w), 709 (w), 684 (m), 660 (m), 610 (w), 602 (w), 573 (m), 555
(w), 522 (w), 475 (w), 448 (w), 426 (w), 408 (w). MS (EI+): 1105,
1103, 1101, [Ag4(C6F5)4isotopic]+, 937, 936, 935, 933
[Ag4(C6F5)3isotopic]+, 383, 382, 381 [AgC6F5·C8H10 + H]+, 382, 381,
380 [AgC6F5·C8H10]+, 335, 334 [C6F5 − C6F5isotopic]+, 168, 167
[C6F5isotopic]+, 134 [C10H14]+, 109, 107 [Agisotopic]+.
−100.4 (dm, o-CF, 1J(13C−19F) = 234 Hz). IR (ATR, 16 scans): 2925
(w), 1644 (w), 1631 (m), 1603 (w), 1557 (w), 1537 (w), 1503 (s),
1447 (s), 1435 (s), 1385 (m), 1379 (m), 1338 (m), 1260 (m), 1152
(w), 1132 (w), 1113 (w), 1074 (m), 1055 (s), 1021 (w), 1001 (w),
979 (w), 956 (s), 892 (w), 882 (w), 821 (m), 775 (w), 755 (w), 745
(m), 716 (w), 703 (w), 684 (m), 660 (w), 644 (w), 594 (m), 573 (w),
542 (m). MS (CI+, isobutane): 1101 [Ag4(C6F5)4 + H]+, 933
[Ag4(C6F5)3]+, 334 [C6F5 − C6F5]+, 121 [C9H12 + H]+, 120 [C9H12]+.
Crystals suitable for X-ray crystallographic analysis were obtained
directly from the above reaction solution.
(AgC6F5)4·2 (1,3,5-trimethylbenzene). Mp: 83 °C (dec). Anal.
(AgC6F5)4·2 (1,2,3,4,5-pentamethylbenzene) n-hexane solvate.
Mp: 117.8 °C. Anal. Calcd for (AgC6F5)4·C11H16·0.5 C6H14 (elemental
analysis was performed with the dried n-hexane solvate), % (found): C
35.32 (36.46); H 1.87 (1.60). 1H NMR (25 °C, CD2Cl2, 250.13
MHz): δ = 2.14 (s, 6H, 2ArCH3), 2.18 (s, 3H, ArCH3), 2.19 (s, 6H,
2ArCH3), 6.77 (s, 1H, ArCH). 13C{1H} NMR (25 °C, CD2Cl2, 62.89
MHz): δ = 16.15 (s, 2CH3, pentamethylbenzene), 16.52 (s, CH3,
pentamethylbenzene), 20.81 (s, 2CH3, pentamethylbenzene), 101.5
(br, ipso-C), 129.28 (s, CH, pentamethylbenzene), 132.68 (s, 2C,
pentamethylbenzene), 133.65 (s, 2C, pentamethylbenzene), 135.25 (s,
Calcd for (AgC6F5)4·2C9H12, % (found): C 37.64 (37.47); H 1.81
1
(2.10). H NMR (25 °C, CD2Cl2, 250.13 MHz): δ = 2.25 (s, 9H,
ArCH3), 6.77−6.79 (m, 3H, ArCH). 13C{1H} NMR (25 °C, CD2Cl2,
62.89 MHz): δ = 21.5 (s, 3CH3, 1,3,5-trimethylbenzene), 101.5 (br,
ipso-C), 127.2 (s, 3CH, 1,3,5-trimethylbenzene), 137.5 (dm, m-CF,
1J(13C−19F) = 259 Hz), 138.4 (s, 3C, 1,2,3-trimethylbenzene), 144.8
1
1
(dm, p-CF, J(13C−19F) = 259 Hz), 153.6 (dm, o-CF, J(13C−19F) =
234 Hz). 19F{1H} NMR (25 °C, CD2Cl2, 282.4 MHz): δ = −158.2
(m, m-CF, 1J(13C−19F) = 259 Hz), −144.1 (dm, p-CF, 1J(13C−19F) =
1
C, pentamethylbenzene), 137.9 (dm, m-CF, J(13C−19F) = 253 Hz),
259 Hz), −100.4 (dm, o-CF, J(13C−19F) = 234 Hz). IR (ATR, 16
1
144.7 (dm, p-CF, 1J(13C−19F) = 250 Hz), 153.8 (dm, o-CF,
1J(13C−19F) = 226 Hz). 19F{1H} NMR (25 °C, CD2Cl2, 282.4
MHz): δ = −158.2 (m, m-CF, 1J(13C−19F) = 259 Hz), −144.1 (dm, p-
scans): 2929 (w), 1630 (m), 1603 (w), 1557 (w), 1537 (w), 1532 (w),
1502 (s), 1446 (s), 1434 (s), 1378 (m), 1342 (m), 1336 (m), 1260
(m), 1199 (w), 1131 (w), 1094 (m), 1072 (s), 1053 (s), 1007 (w),
979 (m), 955 (s), 882 (w), 839 (m), 775 (s), 745 (m), 713 (w), 690
(m), 661 (w), 640 (w), 594 (m), 574 (m). MS (CI+, isobutane): 1100
[Ag4(C6F5)4]+, 933 [Ag4(C6F5)3]+, 334 [C6F5 − C6F5]+, 223 [C6F5 −
C4H8]+, 135 [C10H14 + H], 133 [C10H13]+, 121 [C9H12 + H]+, 120
[C9H12]+, 119 [C9H11]+, 105 [C8H9]+. Crystals suitable for X-ray
crystallographic analysis were obtained directly from the above
reaction solution by storage at ambient temperature.
1
1
CF, J(13C−19F) = 259 Hz), −100.4 (dm, o-CF, J(13C−19F) = 234
Hz). IR (ATR, 16 scans): 3003 (w), 2921 (w), 2867 (w), 1630 (m),
1603 (m), 1558 (w), 1533 (w), 1500 (s), 1442 (s), 1428 (s), 1386
(m), 1372 (m), 1335 (m), 1289 (w), 1256 (m), 1130 (w), 1111 (w),
1071 (m), 1052 (s), 1010 (m), 952 (s), 895 (w), 866 (m), 798 (w),
743 (m), 714 (w), 683 (w), 667 (w), 589 (m), 534 (w). MS (EI+):
1105, 1103, 1101, 1099 [Ag4(C6F5)4isotopic]+, 937, 936, 935, 933
[Ag4(C6F5)3isotopic]+, 383, 382, 381 [AgC6F5·C8H10]+, 335, 334 [C6F5
− C6F5isotopic]+, 382, 381, 380 [AgC6F5·C8H10]+, 168, 167
[C6F5isotopic]+, 149, 148 [C11H16isotopic]+, 148 [C11H16]+, 109, 107
[Agisotopic]+. Crystals suitable for X-ray crystallographic analysis were
obtained from the filtered, saturated reaction solution after addition of
n-hexane.
(AgC6F5)4·2 (1,2,3,5-tetramethylbenzene). Mp: 96.98 °C. Anal.
Calcd for (AgC6F5)4·2C10H14, % (found): C 38.63 (38.27); H 2.06
1
(2.38). H NMR (25 °C, CD2Cl2, 300.13 MHz): δ = 2.12 (s, 3H,
ArCH3), 2.21 (s, 3H, ArCH3), 2.23 (s, 6H, 2ArCH3), 6.80 (s, 2H,
2ArCH). 13C{1H} NMR (25 °C, CD2Cl2, 75.47 MHz): δ = 15.2 (s,
CH3, 1,2,3,5-tetramethylbenzene), 20.8 (s, 2CH3, 1,2,3,5-tetramethyl-
H
DOI: 10.1021/acs.organomet.5b00492
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
(27) Dong, Y. B.; Jin, G. X.; Smith, M. D.; Huang, R. Q.; Tang, B.;
Zur Loye, H. C. Inorg. Chem. 2002, 41, 4909−4914.
(28) Dong, Y. B.; Xu, H. X.; Ma, J. P.; Huang, R. Q. Inorg. Chem.
2006, 45, 3325−3343.
ASSOCIATED CONTENT
* Supporting Information
Text, figures, and tables giving synthetic and characterization
data, computational procedures, and X-ray data. The
Supporting Information is available free of charge on the
ACS Publications website at DOI: 10.1021/acs.organo-
met.5b00492.
■
S
(29) Genuis, E. D.; Kelly, J. A.; Patel, M.; McDonald, R.; Ferguson,
M. J.; Greidanus-Strom, G. Inorg. Chem. 2008, 47, 6184−6194.
(30) Jeffries, P. M.; Wilson, S. R.; Girolami, G. S. J. Organomet. Chem.
1993, 449, 203−209.
(31) Klausmeyer, K. K.; Feazell, R. P.; Reibenspies, J. H. Inorg. Chem.
2004, 43, 1130−1136.
AUTHOR INFORMATION
Corresponding Author
*E-mail: axel.schulz@uni-rostock.de.
Notes
■
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854−861.
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The authors declare no competing financial interest.
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DOI: 10.1021/acs.organomet.5b00492
Organometallics XXXX, XXX, XXX−XXX