Lewis Acid Catalyzed Synthesis of Cyanidophosphates

Article abstract of DOI:10.1002/chem.201504523

Salts containing new cyanido(fluorido)phosphate anions of the general formula [PF_6-n(CN)_n]^- (n=1-4) were synthesized by a very mild Lewis-acid-catalyzed synthetic protocol and fully characterized. All [PF_6-n(CN)_n]^- (n=1-4) salts could be isolated on a preparative scale. It was also possible to detect the [PF(CN)₅]^- but not the [P(CN)₆]^- anion. The best results with respect to purity, yield, and low cost were obtained when the F^-/CN^- substitution reactions were carried out in ionic liquids. Cyanido(fluorido)phosphates: Salts containing [PF_6-n(CN)_n]^- (n=1-4) ions were isolated on a preparative scale by utilizing Lewis acids (LA) catalysts under mild conditions (see equation). The best results with respect to purity, yield, and low cost were obtained when the F^-/CN^- substitution reactions were carried out in ionic liquids.

Full text of DOI:10.1002/chem.201504523

DOI: 10.1002/chem.201504523
Full Paper
&
Cyanidophosphates
Lewis Acid Catalyzed Synthesis of Cyanidophosphates
Kevin Bläsing,[a] Stefan Ellinger,[c] Jçrg Harloff,[a] Axel Schulz,*[a, b] Katharina Sievert,[a]
Christoph Täschler,[c] Alexander Villinger,[a] and Cornelia Zur Täschler[c]
Abstract: Salts containing new cyanido(fluorido)phosphate
anions of the general formula [PF6Àn(CN)n]À (n=1–4) were
synthesized by a very mild Lewis-acid-catalyzed synthetic
protocol and fully characterized. All [PF6Àn(CN)n]À (n=1–4)
salts could be isolated on a preparative scale. It was also
possible to detect the [PF(CN)5]À but not the [P(CN)6]À anion.
The best results with respect to purity, yield, and low cost
were obtained when the FÀ/CNÀ substitution reactions were
carried out in ionic liquids.
Introduction
The first attempts to synthesize cyanidophosphates date back
to 1982, when Dillon and Platt reported on the generation of
[Et4N][PCl6Àn(CN)n] (n=1–3). They studied the reaction of
[PCl6]À salts with AgCN (Scheme 1). However, none of these
salts were isolated and fully characterized.[1] Chevrier et al. pub-
lished 19F NMR data of the [PF5(CN)]À ion,[2] and a little later
Dillon et al. 31P NMR data of reaction mixtures containing
[PF6Àn(CN)n]À (1ꢀnꢀ4) and [PF3Cl3Àn(CN)n]À ions (1ꢀnꢀ3).[1]
These reaction mixtures were obtained on treating PF5 with
[Et4N]CN or [PCl4(CN)2]À salts with AgF.
Scheme 2. Synthesis of PV pseudohalogen species.
[PCl4(CN)2] starting from PCl5 and an excess of KCN [Scheme 2,
Eq. (2)]. Besides, under the same reaction conditions Roesky
was able to isolate [Ph4P][P(N3)6] but not a salt containing the
[P(CN)6]À ion. Only recently, the first cyanido(fluorido)phos-
phate [BMIm][PF3(CN)3] (BMIm=1-butyl-3-methylimidazolium)
was isolated from the reaction of [BMIm][PCl3(CN)3] and
Ag[BF4] after a reaction time of 4 d.[11] Furthermore, [nBu4N]
[PF2(CN)4] was obtained by the reaction of [nBu4N][PF6] with an
excess of Me3SiCN under autogenous pressure in a steel auto-
clave at high temperature [180–2108C; Scheme 1, Eq. (2)].[12–15]
By salt metathesis starting from [nBu4N][PF2(CN)4] a series of
M[PF2(CN)4] (M=Ag+, K+, Li+, H5O2+, EMIm+; EMIm=1-ethyl-
3-methylimidazolium) was isolated and fully characterized.
Herein, we report on catalytic FÀ/CNÀ substitution reactions
that lead (depending on the catalyst and reaction conditions)
to the desired [PF6Àn(CN)n]À ions (n=1–4) at ambient tempera-
ture.
Scheme 1. Synthesis of cyanidophosphates.
Interestingly, although salts containing [P(N3)6]À [Scheme 2,
Eq. (5)] or [P(NCS)6]À ions are known and easily accessible,[3–8]
hexacyanidophosphates M[P(CN)6] are still unknown. As early
as 1930 Gall and Schüppen[9] attempted to generate phospho-
rus(V) pentacyanide by treating P(CN)3 with (CN)2 [Scheme 2,
Eq. (3)]. In 1967 Roesky[10] reported on the synthesis of [nBu4N]
[a] K. Bläsing, Dr. J. Harloff, Prof. Dr. A. Schulz, K. Sievert, Dr. A. Villinger
Institut für Chemie, Universität Rostock
Albert-Einstein-Strasse 3a, 18059 Rostock (Germany)
E-mail: axel.schulz@uni-rostock.de
Results and Discussion
Homepage: http://www.schulz.chemie.uni-rostock.de/
Synthesis: general aspects
[b] Prof. Dr. A. Schulz
Abteilung Materialdesign, Leibniz-Institut für Katalyse e.V.
an der Universität Rostock, Albert-Einstein-Strasse 29a
18059 Rostock (Germany)
We focus on the reaction conditions and catalytic performance
of different Lewis acids in the FÀ/CNÀ substitution reaction as
well as thermodynamic considerations. Detailed data with re-
spect to characterization, workup, and IR/Raman spectra
listed in the Supporting Information are not discussed in detail
here.
[c] Dr. S. Ellinger, Dr. C. Täschler, Dr. C. Zur Täschler
Lonzastrasse, 3930 Visp (Switzerland)
Supporting information and ORCID from the author for this article are
available on the WWW under http://dx.doi.org/10.1002/chem.201504523.
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Reaction of [Ph3C][PF6] with Me3SiCN
workup [nBu4N][PF2(CN)4] at ambient temperature (besides
Me3SiCl). Since this reaction is rather violent at 258C, we stud-
ied the influence of the temperature on the product distribu-
tion in detail (Table 1). Hence, the reaction of [Ph3C][PF6] with
ten equivalents of Me3SiCN was carried out in CH2Cl2 at differ-
ent temperatures for 30 min and then quenched with one
equivalent of [nBu4N]Cl (Scheme 3).
An intensive study on the reaction of [nBu4N][PF6] with an
excess of Me3SiCN (10 equiv) clearly indicated that increasing
the reaction temperature above 2008C led to polymerization
of Me3SiCN and decomposition of the product, and increasing
the excess of Me3SiCN also did not lead to further substitution
or an increase in the overall yield.[12] For this reason we studied
the influence of the cation on the substitution reaction. Sur-
prisingly, when we used [Ph3C][PF6] instead of [nBu4N][PF6], an
immediate violent reaction occurred at room temperatures on
addition of Me3SiCN (10 equiv) and resulted in the exclusive
formation of the [PF2(CN)4]À ion as indicated by 19F and
31P NMR experiments (Scheme 3, Table 1, and Supporting Infor-
Remarkably, already at À508C (after 30 min reaction time)
neither [PF6]À nor large amounts of [PF5(CN)]À could be detect-
ed, but almost exclusively cis/trans-[PF4(CN)2]À (67/31%), as
shown by 19F and 31P NMR experiments (Supporting Informa-
tion, Tables S22 and S23). In the temperature range between
À50 and À308C only the [PF4(CN)2]À ion was obtained, but
with changing cis/trans ratios (Table 1). In accord with comput-
ed thermodynamic data, with increasing temperature forma-
tion of the trans isomer is favored (by 1.25 kcalmolÀ1; see
below and Supporting Information, Table S24). Above À108C
an increasing amount of [mer-PF3(CN)3]À was observed. On the
basis of these results, we developed a synthetic protocol for
the isolation of M[trans-PF4(CN)2] salts (M=K, Li; Scheme 3,
bottom): [Ph3C][PF6] was dissolved in a small amount of CH2Cl2
and the solution cooled to À408C. At this temperature ten
equivalents of Me3SiCN were added and stirring maintained for
30 min at À308C. Now a solution of KOtBu in THF or LiBr in di-
ethyl ether was added and the mixture warmed to ambient
temperature. After workup 74% of K[trans-PF4(CN)2] and 78%
of Li[trans-PF4(CN)2]·2 CH3CN could be isolated and fully char-
acterized (see below and Supporting Information).
Scheme 3. Reactions of [Ph3C][PF6] with Me3SiCN.
Table 1. Product distribution of the reaction of [Ph3C][PF6] with ten
equivalents of Me3SiCN at different temperatures after 30 min reaction
time and quenching with [nBu4N]Cl.[a]
Lewis-acid-catalyzed reactions
T [8C]
[PF5(CN)]À [%]
[PF4(CN)2]À [%]
[PF3(CN)3]À [%]
In another series of experiments only catalytic amounts of
[Ph3C][PF6] were used (Scheme 4). For comparison, first the
standard reaction of [nBu4N][PF6] with an excess of Me3SiCN
(10 equiv) was studied at ambient temperature over a long
time. After 71 h almost full conversion to [nBu4N][PF5(CN)] was
observed (Table 2). Further increase of the reaction time did
not lead to a higher degree of substitution. Only traces (max.
4%) of the doubly substituted species [PF4(CN)2]À were detect-
ed. After workup [nBu4N][PF5(CN)] was isolated in good yield
(82%). Now [Ph3C][PF6] (2–5 mol% with respect to the amount
cis
67
46
6
trans
fac
–
mer
1
À50
À40
À30
À20
À10
1
1
–
–
–
31
51
91
72
45
–
2
–
3
12
<1
–
<1
16
54
[a] The percentages were determined from the integrals of the 19F and
31P NMR data, respectively.
mation Tables S22 and S23). Extraction with n-hexane led to
almost quantitative isolation of Ph3CCN, which was identified
unequivocally by X-ray diffraction (see Supporting Informa-
tion),[16] but no pure [PF2(CN)4]À salt could be obtained. Clearly,
when Ph3CCN is formed quantitatively, then Me3Si+ remains as
possible “cation”, which, however, should form adducts of the
type Me3Si-X-PF2(CN)3 (X=F or CN). Such adducts are assumed
to be highly labile, as discussed by Willner et al. for the analo-
gous Me3Si-NC-B(CN)3 species.[17] Interestingly, the formation of
Ph3CCN was reported before in the reaction of [Ph3C][BF4] with
Me3SiCN, which yields intermediate nitrilium ions[18] of the type
[Ph3C-NC-SiMe3]+ or [Ph3C-NC-CPh3]+ (see below).[19,20] Since in
the tritylium reaction only “Me3Si+” remained as formal cation
for the [PF2(CN)4]À ion, we stopped this reaction by quenching
with one equivalent of [nBu4N]Cl (Scheme 3), which gave after
Scheme 4. General synthesis of [nBu4N][PF6Àn(CN)n] (n=1–4) with Me3SiCN in
the presence of a small amount of a Lewis acid (LA) as catalyst.
Table 2. Product distribution in dependence on the reaction time when
[nBu4N][PF6] is treated with ten equivalents of Me3SiCN at 258C.
Reaction time [h]
1
3
6
17
71
100
[nBu4N][PF6] [%]
[nBu4N][PF5(CN)] [%]
[nBu4N][PF4(CN)2] [%]
71
29
–
34
66
–
8
92
–
3
97
–
–
96
4
–
96
4
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of [nBu4N][PF6]) was added and an immediate reaction was ob-
served. After 2 h reaction, almost pure [nBu4N][PF3(CN)3] was
obtained. In solution, 19F and 31P NMR studies (see below and
Supporting Information, Tables S22 and S23) revealed mainly
the existence of [mer-PF3(CN)3]À and small amounts of [fac-
PF3(CN)3]À besides traces of [PF4(CN)2]À. Again, the favored for-
mation of the mer isomer is supported by computed thermo-
dynamic data (DG298), which indicate a slight preference of the
mer over the fac isomer by 0.6 kcalmolÀ1 (Supporting Informa-
tion, Table S24). Prolonged reaction time and larger amounts
of catalysts did not lead to further substitution.
Table 4. The cis/trans ratios of [PF4(CN)2]À (reaction of [nBu4N][PF6] with
10 equiv of Me3SiCN and LA=NbCl5, P(CN)3, and SiCl4).[a]
Lewis acid
NbCl5
t [h]
cis [%]
trans [%]
Total yield [%]
2
80
27
21
90
88
86
94
93
93
20
73
79
10
12
14
6
100
93[b]
73[b]
100
100
>99
88[c]
>99
100
16
26
P(CN)3
SiCl4
114
138
162
16
119
135
7
7
In a next series of experiments we studied the activity of 16
different metal- and nonmetal-based Lewis acids (LAs). In
Table 3 all utilized catalysts are arranged according to their ac-
tivity with respect to the reaction shown in Scheme 4 along
with data for the uncatalyzed reaction. The blind trial reaction
[a] The percentages were determined from the integrals of the 19F and
31P NMR data, respectively. [b] Difference to 100% was found due to in-
creasing formation of the [PF3(CN)3]À ion. [c] Difference to 100%, since
[PF5(CN)]À was still observed (no full conversion).
SbF5 and GaCl3 even small amounts of the tetracyanido species
[PF2(CN)4]À were detected. In all these reactions again mixtures
of mer/fac isomers were observed; however, [mer-PF2(CN)4]À
was always the major product, in accord with calculations
Table 3. Product distribution of [nBu4N][PF6Àn(CN)n] determined from 19F
and 31P NMR data of the reaction of [nBu4N][PF6] with 10 equiv of
Me3SiCN and 5mol% of a Lewis acidic catalyst at 258C.
(DG ,
298 merÀfac =0.6 kcalmolÀ1, Table S24 in the Supporting Infor-
Lewis acid t [h] n=0 [%] n=1 [%] n=2 [%] n=3 [%] n=4 [%]
mation). The amount of [PF2(CN)4]À increased only marginally
with increasing reaction time, for example, up to 7% when
GaCl3 was used as catalyst (t=44 h). As discussed above, the
larger the number of cyano groups attached to the phospho-
rus atom, the smaller the energy gain by FÀ/CNÀ substitution
(see below). Therefore, we raised the temperature to 1208C
(reflux conditions, Table 5). Without catalysts the reaction yield-
–
–
SbF3
6
100
120 <0.5
120
54
21
4
3
22
2
114
135
80
68
6
3
1
2
8
–
92
96
>99
>99.5
>99.5
99
96
92
–
–
–
4
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
<1
<1
–
1
2
<0.5
<0.5
<0.5
–
4
8
100
100
100
100
–
<1
1
<1
1
MnCl2
CrCl3
AgCN
FeCl3
AlCl3
[T-F-T]+
NbCl5
P(CN)3
SiCl4
B(C6F5)3
BCl3
TiCl4
PCl5
SbF5
GaCl3
–
–
1
–
–
–
–
–
–
–
Table 5. Product distribution of [nBu4N][PF6Àn(CN)n] (n=2–4) in the reac-
tion of [nBu4N][PF6] with ten equivalents of Me3SiCN and 5 mol% of
a Lewis acidic catalyst (T=1208C).[a]
–
–
–
–
–
–
–
–
–
100
>98
>98
>99
98
97
[a]
–
–
–
–
Lewis acid
t [h]
n=2 [%]
n=3 [%]
n=4 [%]
none
AlCl3
SbF3
P(CN)3
NbCl5
SbF5
PCl5
BCl3
GaCl3
TiCl4
7
28
3
5
6
3
3
7
6
6
84
43
77
<1
<1
<1
<1
–
16
57
23
>99
>97
>97
>94
92
–
–
–
<1
2
2
5
8
14
12
1
[a] BCl3 was used as 1m solution in n-hexane. [b] T=Me3Si.
always stopped at the stage of the [PF5(CN)]À anion (see
above). LAs with a low solubility in Me3SiCN, such as FeCl3 and
AlCl3, did not much accelerate the reaction, and some even
seemed to inhibit the reaction (SbF3, MnCl2, CrCl3). However,
the advantage of using SbF3, MnCl2, and CrCl3 was that they re-
sulted in the formation of almost pure [nBu4N][PF5(CN)]. Much
better catalyst solubility was found for NbCl5, P(CN)3,and SiCl4;
hence, over a long period exclusively the [PF4(CN)2]À anion was
formed. Interestingly, the ratio of the cis/trans isomers depend-
ed on the catalyst and, in the case of NbCl5, also on the reac-
tion time (Table 4). It seems as if first the cis isomer was
formed and slowly transformed into the trans isomer, which is
favored by 1.25 kcalmolÀ1. This transformation was significantly
enhanced when NbCl5 was used.
–
–
86
88
[a] The percentages were determined from the integrals of the 19F and
31P NMR data, respectively.
ed 84% of [PF4(CN)2]À and 16% of [PF3(CN)3]À. In all catalytic
reactions [PF3(CN)3]À was detected as main product, often with
considerable amounts of [PF2(CN)4]À. With P(CN)3 and NbCl5 it
was now possible (contrary to the reaction at room tempera-
ture) to exclusively generate [PF3(CN)3]À and finally to isolate
[PF3(CN)3]À salts. The fac/mer ratio was found to be 50:50, that
is, no preference was observed for [mer-PF3(CN)3]À. With PCl5,
BCl3, GaCl3, and TiCl4 it was feasible to increase the amount of
[PF2(CN)4]À. However, with the best catalysts, such as GaCl3, the
Utilization of the strong (hard) Lewis acids BCl3, TiCl4, PCl5,
SbF5, and GaCl3 led to the formation of rather pure [nBu4N]
[PF3(CN)3] in fast substitution reactions (Table 3). In case of
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reaction stopped at a [PF3(CN)3]À/[PF2(CN)4]À ratio of 86/14%. It
was impossible to further improve the ratio with respect to
[PF2(CN)4]À simply by increasing the reaction time or changing
the stoichiometry. Interestingly, at elevated temperatures the
amount of [fac-PF3(CN)3]À increased (GaCl3: 58%). Note that
these reactions can be used to isolate salts of the [PF4(CN)2]À
or [PF3(CN)3]À ions in rather good yields (95 and 87%).
To increase the amount of [PF2(CN)4]À, a combination of cat-
alytic process and autoclave reaction was applied (Table 6).
When starting from [PF6]À with GaCl3 as catalyst, raising the re-
action time and temperature only slowly increases the amount
of [PF2(CN)4]À and always mainly mixtures of [PF3(CN)3]À and
Scheme 5. Synthesis of M[PF6Àn(CN)n] (M=Li, K; n=2, 3).
trans. When this reaction was carried out at 1208C, after 1 h
pure Li[PF3(CN)3] [Scheme 5, Eq. (7)] was isolated as a mixture
of 91% mer and 9% fac species, as indicated by
19F NMR experiments. Recrystallization from CH3CN/
Table 6. Product distribution of [nBu4N][PF6Àn(CN)n] in the reaction of [nBu4N]+ salts
benzene afforded Li[PF3(CN)3]·2CH3CN in 82% yield.
The corresponding potassium salt K[PF3(CN)3] could
be synthesized in 81% yield already after 3 h at 608C
with 5 mol% [Ph3C][PF6] as catalyst [Scheme 5,
Eq. (8); isomer ratio: 11% fac/89% mer]. Recrystalliza-
tion as described above also afforded an acetonitrile
solvate, namely, K[PF3(CN)3]·2CH3CN.
with 5 mol% GaCl3 (LA) and Me3SiCN in an autoclave at different temperatures.[a]
Starting ion T [8C] t [h] Me3SiCN [equiv] n=2 [%] n=3 [%] n=4 [%] n=5 [%]
[PF6]À
[PF6]À
[PF6]À
150
160
140
15
15
20
20
15
10
10
20
20
30
1
1
–
–
–
76
61
82
4
22
37
17
92
90
1
1
1
4
[PF3(CN)3]À 140
[b]
–
150
–
10
[a] The percentages were determined from the integrals of the 19F and 31P NMR data,
respectively. [b] Product mixture composed of 82 % [nBu4N][PF3(CN)3], 17 % [nBu4N]
[PF2(CN)4], and 1 % [nBu4N][PF(CN)5].
Synthesis of [nPr3NH][PF6Àn(CN)n]: an ideal precur-
sor for the generation of M[PF6Àn(CN)n] salts
Besides temperature, stoichiometry, catalyst, and re-
action time, the cation also has a considerable influ-
[PF2(CN)4]À were detected within reasonable reactions times
ence on the product distribution. Moreover, with respect to
easy cation-exchange reactions we were interested in prepar-
ing [nPr3NH][PF6Àn(CN)n] salts (Scheme 6), which should be suit-
able for the preparation of almost any other M[PF6Àn(CN)n] salt
(see below).
(t<1d). The best results were obtained when [PF3(CN)3]À was
used as starting material. In this case almost quantitative con-
version to [PF2(CN)4]À was achieved after 20 h at 1408C. Also
small amounts of the pentacyanido product were detected,
which led to the idea to run more cycles and isolate
the [PF2(CN)4]À/[PF(CN)5]À mixture in each run. In this
way we were able to enrich [PF(CN)5]À up to 25%
after three cycles but stopped at this stage. Further
increase of the temperature beyond 1608C did not
give better yields of [PF(CN)5]À, since rapidly increas-
ing decomposition hampered better yields of
[PF(CN)5]À. Hence, only a stepwise procedure includ-
ing isolation of the reaction mixture followed by re-
Scheme 6. Synthesis of [nPr3NH][PF6Àn(CN)n] and application in salt metathesis (M=Li, K).
action with additional fresh Me3SiCN/GaCl3 allows the time-
consuming (rather expensive) generation of salts containing
the [PF(CN)5]À anion.
Access to [nPr3NH][PF5(CN)] [Scheme 6, Eq. (9)] was easily
gained by reaction of [nPr3NH][PF6] with Me3SiCN at room tem-
perature after 20 h without any catalyst. At slightly elevated
temperature (608C, no catalyst) [nPr3NH][PF4(CN)2] was isolated
after 6 h (99% yield). Contrary to the reaction with [nBu4N]
[PF6], even [nPr3NH][PF2(CN)4] was obtained after 50 h under
reflux conditions (1208C, no catalyst, 95%). It can be assumed
that the reason for this cation effect may be the fact that
[nPr3NH][PF6Àn(CN)n] are ionic liquids (see Table 7), and thus
almost complete solubility is ensured, besides the fact that
small amounts of a Lewis acid of the type PF5Àn(CN)n could be
formed intrinsically by thermally induced decomposition ac-
cording to [nPr3NH][PF6Àn(CN)n]!nPr3N+HF+PF5Àn(CN)n.
Direct synthesis of alkali metal cyanidophosphates
Treatment of M[PF6] (M=Li, K) with ten equivalents of
Me3SiCN without a catalyst led after 15 h at ambient tempera-
ture to the formation of 50% Li[PF5(CN)] besides 50% of the
starting material Li[PF6]. When the reaction was carried out at
slightly elevated temperature (608C) full conversion to
Li[PF5(CN)] (>99%) was found within 3.5 h. On adding a cata-
lyst (5 mol% of [Ph3C][PF6]), Li[PF4(CN)2] was isolated after 15 h
at 258C [Scheme 5, Eq. (6)]. After recrystallization from CH3CN/
benzene pure Li[PF4(CN)2]·2CH3CN was obtained in 84% yield.
According to 19F NMR studies, the isomer ratio was 96/4% cis/
Of course, utilization of Lewis acids as catalyst also enhances
the substitution reaction in [nPr3NH][PF6]. Utilization of 5 mol%
PCl5 or GaCl3 yielded [nPr3NH][PF3(CN)3] after 22 h at room tem-
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Table 7. Comparison of melting points [8C] of [nPr3NH][PF6Àn(CN)n] salts
(n=0–4) and selected (experimental) vibrational data n˜CN [cmÀ1].
Table 8. Calculated gas-phase Gibbs energies DG298 [kcalmolÀ1] for the
consecutive substitution reactions.
[PF6]À
[PF5(CN)]À
[PF4(CN)2]À
[PF3(CN)3]À
PF2(CN)4]À
Reaction step[a]
DG298
m.p.
n1CN
n2CN
260
–
–
164
2212
–
À10
2204
–
À2
8
2195
2200
[PF6]À +TCN
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
[PF5(CN)]À +TF
À9.12
À5.59
À6.83
À2.48
À3.07
À3.72
À4.31
+0.24
À0.35
À2.47
À3.06
À0.09
À2.80
+2.48
À19.10
2199
2208
[PF5(CN)]À +TCN
[cis-PF4(CN)2]À +TF
[trans-PF4(CN)2]À +TF
[fac-PF3(CN)3]À +TF
[mer-PF3(CN)3]À +TF
[fac-PF3(CN)3]À +TF
[mer-PF3(CN)3]À +TF
[trans-PF2(CN)4]À +TF
[trans-PF2(CN)4]À +TF
[cis-PF2(CN)4]À +TF
[cis-PF2(CN)4]À +TF
[PF(CN)5]À +TF
[PF5(CN)]À +TCN
[trans-PF4(CN)2]À +TCN
[trans-PF4(CN)2]À +TCN
[cis-PF4(CN)2]À +TCN
[cis-PF4(CN)2]À +TCN
[mer-PF3(CN)3]À +TCN
[fac-PF3(CN)3]À +TCN
[mer-PF3(CN)3]À +TCN
[fac-PF3(CN)3]À +TCN
[cis-PF2(CN)4]À +TCN
[trans-PF2(CN)4]À +TCN
[PF(CN)5]À +TCN
perature. The [PF2(CN)4]À salt was obtained after 24 h at 1208C
with GaCl3 as catalyst. Interestingly, on using 30 equivalents
(instead of 10 equiv) of Me3SiCN and 8 mol% GaCl3, we ob-
served a mixture of 93% [PF2(CN)4]À and 7% [PF(CN)5]À after
5 h at 1208C. Except for [PF(CN)5]À, all four [nPr3NH][PF6Àn(CN)n]
(n=1–4) were isolated and characterized (Table 7, see Support-
ing Information). [nPr3NH][PF6Àn(CN)n] (n=2–4) are room-tem-
perature ionic liquids.
[PF(CN)5]À +TF
[P(CN)6]À +TF
[PF6]À +6TCN
[P(CN)6]À +6TF
[a] T=Me3Si.
Synthesis of M[PF6Àn(CN)n] in [nPr3NH][PF6Àn(CN)n] ionic liq-
uids
the substitution reaction for the last step is endergonic (n=6:
2.48 kcalmolÀ1).
The major advantage of [nPr3NH][PF6Àn(CN)n] salts is the possi-
bility to carry out simple acid–base reactions (neutralization),
that is, to use metal bases such as metal hydroxides
[Scheme 6, Eq. (11)] for facile cation exchange without making
a detour by using, for example, silver salts or additional sol-
vents. In this case the only side products are H2O and nPr3N,
which are easily removed in vacuo. This route saves costs and
chemicals. Besides, almost any of the M[PF6Àn(CN)n] (n=1–4)
salts are easily and quickly accessible. Also cyanidophosphates
with Mn+ (n=2–3) can be synthesized by this approach, which
will be published elsewhere. To test this procedure, we pre-
pared all M[PF6Àn(CN)n] (n=1–4; M=Li, K) salts using KOH or
LiOH·H2O in yields of 80–90%.
Experimentally, the specific odor of nPr3N was detected at
once after adding the base. After 2 h reaction time, removal of
all volatile substances, and repeated washing with CH2Cl2, the
M[PF6Àn(CN)n] salts were obtained in good yields (80–90%).
Single crystals could be obtained by recrystallization from
CH3CN/benzene. The nPr3N can be recovered, since it can
easily be separated from H2O and CH2Cl2 by distillation.
Natural bond order analysis revealed successive decreases of
the positive partial charge at the P atom by about +0.3e per
substitution step (+2.77 to +1.03e), while the charge at the F
atoms only slightly decreases (À0.63 to À0.57e). Interestingly,
the polarity of the PÀF (ca. 13/87%) and PÀC bonds (ca. 71/
29%) does not change significantly on substitution (Support-
ing Information, Table S29).
As proven by experiments, adding a Lewis acid facilitates
fluoride abstraction. A measure for the intrinsic stability of the
[PF6Àn(CN)n]À ions is the Lewis acidity of the parent Lewis acid
PF5Àn(CN)n (n=1–5), for example, PF5 for the [PF6]À ion.[21] Ac-
cording to our DFT computations, the Lewis acidity of
PF5Àn(CN)n (n=1–5) is strongly increased compared to PF5 and
definitely plays an important role in the catalytic cycle of the
Lewis-acid-catalyzed FÀ/CNÀ exchange reaction (see below). A
good measure of the Lewis acidity is the fluoride-ion affinity
(FIA),[21–26] which combines the strength of a Lewis acid LA(g)
with the energy that is released on binding a fluoride ion in
the gas phase: LA(g) +FÀ(g)![LA–F]À(g) +DH298
, with FIA=
ÀDH298. For example, the FIA values increase in the order PF5
(101.5, cf. experimental value 101(8)[24])<PF4(CN) (110.5) <
PF3(CN)2 (119.0)<PF2(CN)3 (122.2)<PF(CN)4 (130.8)<P(CN)5
(141.0 kcalmolÀ1). Thus, P(CN)5 has a considerably larger FIA
than PF5 (141.0 versus 101.5 kcalmolÀ1), which nicely explains
why the last substitution step was experimentally not ob-
served (Supporting Information, Tables S26–28). This actually
means that cyanidation greatly increases the thermodynamic
stability of all cyanidophosphates relative to the perfluorinated
[PF6]À ion. In conclusion, P(CN)5 is a very strong Lewis acid,
much stronger than PF5, lying in the range of SbF5.[21]
Thermodynamic and mechanistic considerations
To shed some light on the thermodynamics of the FÀ/CNÀ sub-
stitution, calculations for the successive substitution were car-
ried out at the M06-2X/aug-cc-pvDZ level of theory. For the
[PF4(CN)2]À and [PF2(CN)4]À ions two isomers were considered
(cis-C2v and trans-D4h) as well as mer and fac isomers of the
[PF3(CN)3]À ion. The Gibbs energies of all substitution reactions
are listed in Table 8. Experimentally, we have demonstrated
that salts containing the [PF6Àn(CN)n]À (n=1–4) anion could be
prepared from [PF6]À and Me3SiCN, and in accord with these
results the gas-phase Gibbs energies for the consecutive sub-
stitution reactions are all (decreasingly) exergonic till n=5
(DG298: À9.12, À6.83, À3.07, À2.47, À0.09 kcalmolÀ1), whereas
The cyanide-ion affinities (CIA, analogous definition to FIA)
increase considerably in the series PF5 <PF4(CN) … <P(CN)5
(PF5: 66.4 versus P(CN)5: 96.3 kcalmolÀ1) but are much smaller
than the FIAs. The difference FIAÀCIA (Supporting Information,
Table S28) also strongly increases along this series (PF5: 35.8
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versus P(CN)5: 47.4 kcalmolÀ1), and this supports the experi-
mental observation that it was impossible to observe the for-
mation of [P(CN)6]À as well as the rather reluctant formation of
[PF(CN)5]À. Moreover, with increasing number of CN groups
PF5Àn(CN)n species become less stable with respect to decom-
position into a PIII species and NCCN (e.g., P(CN)5!P(CN)3 +
terestingly, according to in situ NMR experiments there is no
experimental proof for the generation of the proposed inter-
mediates, that is, either the reaction is fast on the NMR time-
scale or the concentration of the intermediates is very low.
However, the formation of Lewis acidic silylium species of the
type [Me3Si-X-LA] (X=halogen, pseudohalogen, pseudochalco-
gen) in the reaction of Me3SiX with Lewis acids has been de-
scribed before,[18,27–32] as has the use and isolation of silylium
ions in catalysis.[33–37]
NCCN, DG298 =À54.0 kcalmolÀ1
)
Without a catalyst SN1-type reactions at the silicon center of
Me3SiCN seem to occur rather slowly, especially since the
[PF6]À anion is a rather bad nucleophile. By means of Lewis
acids, the SN1-type substitution and fluoride abstraction should
be enhanced by forming a catalyst of the type [Me3Si-CN-LA]
(LA=Lewis acid). In principle three different types of catalytic
cycles (Scheme 7), which can even be superimposed on each
We stress that the catalytic cycles in Scheme 7 are proposals
based on the assumption that Lewis acids in the presence of
a strong donor (such as Me3SiCN) form adducts such as LA-NC-
SiMe3 leading to diminished acidity compared to the free
acids. Moreover, the situation of this formally simple FÀ/CNÀ
substitution becomes rather complex when the concentration/
amount of catalyst/Me3SiCN, the Lewis acidity of the different
catalyst, the countercation of [PF6Àn(CN)n]À, and the increasing
amount of generated Me3SiF in each cycle are taken into ac-
count. Additionally, also the PF5Àn(CN)n species formed in situ
can act as Lewis acids. The halide ligands of Lewis acids such
as GaCl3 may also have an influence on the mechanism. Last
but not least, most of the reactions can be regarded as equilib-
rium reactions that depend on temperature and pressure.
other, can be assumed, since intermediately formed Me3Si+
(solv)
(see Table 3, e.g., [Me3Si-F-SiMe3]+) can also be assumed to act
as Lewis acid, that is, a generalized catalyst can be described
as [LA1-CN-LA2] (where LA1=Me3Si+, LA2=Me3Si+ and all
other considered Lewis acids). Each Lewis acidic center of
[LA1-CN-LA2] can formally interact with the [PF6Àn(CN)n]À
anions to facilitate fluoride abstraction (or CNÀ abstraction). In-
Novel cyanidophosphates: spectroscopic properties and
structure
Melting points
For two sets of cations, [nBu4N]+ and [nPr3NH]+, we were able
to synthesize and fully characterize the corresponding
[PF6Àn(CN)n]À (n=0–4) salts (Table 7 and Table 9). Although the
decomposition temperatures are all rather high (between 200
and 3908C), the melting points display a clear trend. With the
first substitution the melting points drop by almost 1008C
([nBu4N]+: 1668C, [nPr3NH]+ 1648C). With increasing degree of
CNÀ substitution, the melting points of the [nBu4N]+ salts fur-
ther decrease. Hence, the lowest melting point of 648C was
found for [PF2(CN)4]À. For the [nPr3NH]+ salt series the lowest
melting point was found for the [PF4(CN)2]À salt (À108C),
which then slightly increased to 88C for [nPr3NH][PF2(CN)4] (cf.
[EMIm][PF2(CN)4]: À328C).[12]
Table 9. Melting and decomposition points [8C] as well as selected IR
data of [nBu4N][PF6Àn(CN)n] (n=0–4, n˜ [cmÀ1]).
[PF6]À
[PF5(CN)]À
[PF4(CN)2]À
[PF3(CN)3]À
[PF2(CN)4]À
m.p.
Tdecomp
n1CN
250
388
–
166
319
2212
–
95
71
64
305
2204
–
316
2197
2209
316
2193
2202
n2CN
–
NMR spectroscopy
Scheme 7. Proposed catalytic cycles (T=Me3Si, TS=transition state, LA=Le-
wis acid). Top: LA generates the bis-silylated nitrilium ion [T-CN-T]+, which
acts as catalyst; middle and bottom: the LA-NC-T adduct acts as Lewis acidic
catalyst attacking one fluoride ligand of [PF6Àn(CN)n]À, either at the Si center
(middle) or the LA center (bottom).
Generally, with respect to NMR experiments, cyanido(fluorido)-
phosphates are interesting, since all elements of the
[PF6Àn(CN)n]À ion (13C, 14N, 15N, 19F, and 31P) are NMR-active. The
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19F and 31P NMR spectra are depicted in Figures S2–S17 and
the shifts and coupling constants are listed in Tables S22–S23
of the Supporting Information.
Comparison of the 19F NMR data revealed that with increas-
ing number of CN groups the resonances of the F nuclei are
shifted downfield (Supporting Information, Table S22). In gen-
1
eral, heteronuclear JFP coupling constants between 680 and
2
780 Hz were observed, while the homonuclear JFF coupling
constants decrease with increasing number of CN groups
([PF5(CN)]À: 54 Hz, [cis-PF4(CN)2]À: 45 Hz, [mer-PF3(CN)3]À:
35 Hz). On the contrary, the 31P NMR signals are shifted to
higher field with increasing number of CN groups.
Both in the 19F and 31P NMR spectra 13C satellites can be ob-
1
served, and in the 13C NMR spectra the corresponding JPC and
1
2JFC coupling constants could be detected. The JPC coupling
constants decrease in the order [PF5(CN)]À (331 Hz)>[cis-
2
PF2(CN)4]À(218/143 Hz), and JFC coupling constants between
20 and 80 Hz were found.
The [PF6Àn(CN)n]À ions are fairly dynamic species at 298 K,
the temperature at which the spectra were recorded. For ex-
ample, in the 31P NMR spectrum of [PF5(CN)]À a doublet of
quintets was observed at 298 K, which transforms into a sextet
indicating five equivalent F atoms at higher temperatures. In
the case of [cis-PF4(CN)2]À a triplet of triplets was found, which
changes to a quintet at slightly elevated temperatures, an
effect which was already described by Dillon et al.[5] Finally, the
computed data are in good agreement with the experimental-
ly observed values (Supporting Information, Tables S22 and
S23). Hence, if it were possible to generate [P(CN)6]À it should
show a signal at about À370 to À400 ppm in the 31P NMR
spectrum.
Figure 1. ORTEPs of the molecular structures of selected anions in the crys-
tal. Thermal ellipsoids with 50% probability at 173 K.
Structure elucidation
Crystals suitable for single-crystal X-ray structure determination
Table 10. Selected structural parameters of salts containing [PF6Àn(CN)n]À
ions (n=1–4, distances [Š], s=solvent=acetonitrile).
were isolated for K[PF5(CN)], K[trans-PF4(CN)2], Li[trans-
PF4(CN)2]·2CH3CN,
Li[cis-PF4(CN)2]·2CH3CN,
M[mer-
PF3(CN)3]·2CH3CN (M=Li, K), [Ph4P][mer-PF3(CN)3], and [Ph3C]
[PF6]. Details of the structure solutions can be found in Ta-
bles S1–S12 of the Supporting Information. Figure 1 shows one
anion of each example. Selected structural data are listed in
Table 10. As expected for hexacoordinate phosphates, bond
angles close to 90 and 1808 are observed with rather short PÀ
F distances (1.58–1.65 Š, cf. Ærcov(PÀF)=1.82 Š)[38] indicating
highly polar bonds (Supporting Information, Table S29). The
less polar PÀC bonds are significantly longer and range from
1.81 to 1.85 Š (cf. Ærcov(PÀC)=1.86 Š).[38] Since the cyanido/
fluorido ligand accommodates a lone pair at the nitrogen/fluo-
rine atom, strong interactions are found with Lewis acidic cen-
ters such as metal ions (M+···NCÀP and M+···FÀP, see metrical
parameters in Table 11). Hence, in the case of Li+ and K+ salts,
coordination polymers are observed (Supporting Information,
Figure S1). In addition, often if donor solvent molecules were
involved, also solvate formation was observed (e.g., in Li[cis-
PÀF
1.587–1.599
1.590–1.610
PÀC
–
1.844
1.816–1.838
1.848
1.837
1.838
1.821
CN [K+][a] CN [AÀ][b]
[Ph3C][PF6]
K[PF5(CN)]
–
–
[2+7]
–
[2+5]
–
[nBu4N][cis-PF4(CN)2] 1.586-1.612
Li[cis-PF4(CN)2]·2s 1.587–1.592
Li[trans-PF4(CN)2]·2s 1.605–1.607
[4+0][c]
[4+2][c]
[3+7]
–
[2+0]
[2+2]
[4+4]
–
K[trans-PF4(CN)2]
[Ph4P][PF3(CN)3][d]
Li[PF3(CN)3]·2s
1.599–1.610
1.603–1.651
1.5778–1.588 1.843–1.848 [6+0]
[4+0][e]
1.599–1.611
1.603
[3+0]
K[PF3(CN)3]·2 s
K[cis-PF2(CN)4][g]
1.842–1.848 [7+1][f]
1.848–1.850 [5+2]
[3+1]
[6+2]
[a] First coordination number (CN) refers to the number of N atoms inter-
acting with the cation, and the second number to F atoms linked to one
cation. [b] First CN refers to number of cations interacting with the N
atom of the CN groups, and the second number is the CN of the cation
interacting with F atoms. [c] Interaction with two N atoms of two differ-
ent CH3CN molecules. [d] Meridional isomer. [e] Two independent Li+
ions: Li1 only octahedrally coordinated by six CN groups of six different
[PF3(CN)3]À anions, and Li2 only surrounded by four CH3CN solvent mole-
cules in a tetrahedral fashion. [f] Only two of the N atoms belong to two
different anions, and four N atoms of four different CH3CN solvent mole-
cules are additionally coordinated. [g] Taken from ref. [12].
PF4(CN)2]·2CH3CN,
Li[trans-PF4(CN)2]·2CH3CN,
and
M[PF3(CN)3]·2CH3CN). Whereas Li+ ions are tetrahedrally or oc-
tahedrally surrounded by N atoms with only very weak M···F
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Table 11. Selected cation–anion and cation–solvent metrical parameters
of salts containing [PF6Àn(CN)n]À ions (n=1–4, distances [Š], s=solvent=
acetonitrile).
MÀF[a]
MÀN[b]
MÀNs
K[PF5(CN)]
2.70–3.58
2.69–3.70
2.76
2.75
–
2.89–2.91
2.82–2.95
2.90–2.93
2.86-3.26
2.04
–
–
K[trans-PF4(CN)2]
K[PF3(CN)3]·2s
K[cis-PF2(CN)4]
Li[cis-PF4(CN)2]·2s
Li[trans-PF4(CN)2]·2s
Li[PF3(CN)3]·2s
2.95–2.97
–
2.01
2.01
2.03
–
2.76
2.03
2.21–2.26
[a] M=K: K···F distances shorter than ÆrvdW(K···F)=4.22 Š; M=Li: Li···F
distances shorter than ÆrvdW(Li···F)=3.28 Š (vdW=van der Waals).[39]
[b] M=K: K···N distances shorter than ÆrvdW(K···N)=4.30 Š; M=Li: Li···N
distances shorter than ÆrvdW(Li···N)=3.36 Š.[39]
interactions, the potassium salts always show strong K···F and
K···N interactions leading to coordination numbers of 7–10. Of
special interest seems to be the structure of Li[mer-
PF3(CN)3]·2CH3CN (space group I41/a with eight formula units
per cell), since two different coordination modes are found for
the Li+ ions: 1) Li1 is octahedrally surrounded by six CN
groups of six different [mer-PF3(CN)3]À ions (Figure 2, top). Two
CN groups (with one trans F ligand at the anion) adopt a trans
coordination mode around the Li1 ion (LiÀN 2.212(2) Š), and
four CN groups (with only cis F ligands at the anion) form
a square-planar coordination environment around the Li1 ion
(LiÀN 2.260(2) Š). These four CN groups link four different
anions forming sheets composed of 24-membered rings
(Figure 2, top view), which lie in the ab plane. These sheets are
linked by the remaining two CN interactions per anion with
the Li1 ion yielding a 3D network with large voids (Figure 2
middle), since the fluoride ligands are not involved in the Li+
coordination. 2) Li2 is tetrahedrally surrounded by four acetoni-
trile molecules (Li2ÀN 2.039(1) Š). These [Li(CH3CN)4]+ tetrahe-
dra sit in the huge voids described above. As depicted in
Figure 2 (bottom), the polyhedral representation shows linked
[mer-PF3(CN)3]À octahedra and Li1N6 octahedra and isolated
Li2N4 tetrahedra.
Figure 2. Solid state structure of Li[mer-PF3(CN)3]·2CH3CN. Top: Section of
the 3D network displaying 24-membered rings and the coordination around
Li1 and Li2. Middle: solid-state structure without the Li(CH3CN)4]+ units dis-
playing large voids. Bottom: polyhedral representation with octahedral [mer-
PF3(CN)3]ÀÀ ions (orange) and Li1 (green octahedra) and Li2 coordination
(blue tetrahedra), viewed along the a axis.
In contrast to Li[mer-PF3(CN)3]·2CH3CN, the analogous potas-
sium salt K[mer-PF3(CN)3]·2CH3CN crystallizes in the orthorhom-
bic space group Pnma with four formula units per cell. All K+
ions adopt the same coordination environment, which is best
described as a [3+4+1] coordination, that is, three N atoms of
three different anions (K···N 2.9325(9) Š), four N atoms of four
different CH3CN molecules (K···N 2.9710(9) Š), and one fluorido
ligand of a fourth anion (K···F 2.7552(7) Š, Table 11) interacts
with the K+ ions leading to a 2D network (Supporting Informa-
tion, Figure S1).
Figure 3. Molecular structure of Li[PF5(CN)]·3THF.
The silver salt Ag[mer-PF3(CN)3], obtained from K[mer-
PF3(CN)3]·2CH3CN and AgNO3, crystallized isotypically to Li[mer-
PF3(CN)3]·2CH3CN. Moreover, only the molecular species was
observed in Li[PF5(CN)]·3THF, which crystallized from tetrahy-
drofuran (space group P21/c with four formula units per cell).
Since only a rather poor data set was obtained we abstain
from a detailed discussion, but we do stress that the connec-
tivity could be clarified (Figure 3).
Conclusions
Several salts containing cyanido(fluorido)phosphate anions of
the general formula [PF6Àn(CN)n]À (n=1–4) could be isolated
by utilizing Me3SiCN and [PF6]À salts. Very mild conditions (am-
bient temperature, low pressures) could be applied if small
amounts of Lewis acids that catalyze the fluoride/cyanide ex-
change reaction were added. The best results were obtained if
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the FÀ/CNÀ substitution reactions were carried out in ionic liq-
uids such as [nPr3HN][PF6Àn(CN)n] and EMIm[PF6Àn(CN)n]. Struc-
tural elucidation revealed the formation of 2D and 3D net-
works in case of Lewis acidic cations in which both the nitro-
gen atom of the cyanide as well as the fluorine atoms of the
anion can act as donor to bind to the M+ center. Hence, the
series of [PF6Àn(CN)n]À ions (n=1–4) can be used for the ration-
al design of coordination polymers and new ionic liquids.
action mixture turns quickly brown, especially during the synthesis
of [nBu4N][PF3(CN)3]. For workup the excess of Me3SiCN and formed
Me3SiF were removed in vacuo. The resulting oil was mixed with
distilled water and aqueous H2O2 (30 wt%). After stirring at 808C
for 5 h and cooling to ambient temperature, the suspension was
filtered and washed twice with water. The product was extracted
from the remaining solid with CH2Cl2 and the extract filtered. The
organic phase was dried over anhydrous Na2SO4 and filtered.
CH2Cl2 was evaporated on a rotary evaporator. The obtained prod-
uct was dried in vacuo for several hours to yield [nBu4N][PF5(CN)],
[nBu4N][PF4(CN)2], or [nBu4N][PF3(CN)3] as white or light yellow
solids.
Experimental Section
General remarks
Synthesis of [nBu4N][PF5(CN)]
Detailed description of all used chemicals, drying procedures, and
so forth can be found in the Supporting Information. All catalytic
tests are described in detail in the Supporting Information and will
not be listed here. All IR/Raman and NMR spectra are depicted in
the Supporting Information, as are details of the X-ray structure
analyses and calculations. Only the most efficient synthetic routes
are listed here; additional methods can be found in the Supporting
Information.
[nBu4N][PF6] (1.04 g, 2.67 mmol), AlCl3 (6 mol%, 21 mg, 0.16 mmol),
and Me3SiCN (2.7 g, 27 mmol) were stirred under argon atmos-
phere at ambient temperature for 3 h followed by NMR measure-
ments on the reaction mixture. According to 19F and 31P NMR data,
the reaction mixture contained 92% [nBu4N][PF5(CN)] and 8%
[nBu4N][PF4(CN)2].
Synthesis of [nBu4N][PF4(CN)2]
Synthesis of [nBu4N][PF5(CN)]
[nBu4N][PF6] (216 mg, 0.56 mmol), [(CH3)3SiFSi(CH3)3][B(C6F5)4]
(1 mol% 5 mg, 5.9 mmol), and Me3SiCN (556 mg, 5.6 mmol) were
stirred under argon atmosphere at ambient temperature for 22 h.
After removing the excess Me3SiCN and formed Me3SiF in vacuo
the resulting solid was washed with n-hexane (2”5 mL). After
drying in vacuo 213 mg (94%, 0.53 mmol) of [nBu4N][PF4(CN)2] was
obtained. According to 19F and 31P NMR measurements the product
is a mixture of both isomers with around 91% [nBu4N][cis-PF4(CN)2]
and 9% [nBu4N][trans-PF4(CN)2]. M.p. 90–958C; Tdecomp =3058C; ele-
mental analysis (%) calcd (found) for C18H36N3PF4 (401.47 gmolÀ1): C
[nBu4N][PF6] (446 mg, 1.15 mmol) and Me3SiCN (1.14 g, 11.5 mmol)
were stirred under argon atmosphere at ambient temperature for
20 h. Then the excess Me3SiCN and formed Me3SiF were removed
in vacuo. The resulting white solid was mixed with distilled water
and aqueous H2O2 (30 wt%). After stirring at 808C for 2 h and cool-
ing to ambient temperature, the suspension was filtered and
washed twice with water. The product was extracted from the re-
maining solid with CH2Cl2 and the extract filtered. The organic
phase was dried over anhydrous Na2SO4 and filtered. CH2Cl2 was
evaporated on a rotary evaporator. The product was dried in vacuo
to obtain 418 mg (92%, 1.06 mmol) of [nBu4N][PF5(CN)] as a white
solid. M.p. 1668C; Tdecomp =3198C; elemental analysis (%) calcd
(found) for C17H36N2PF5 (384.45 gmolÀ1): C 51.76 (51.56), H 9.20
(9.16), N 7.10 (7.10); 1H NMR (300 K, [D6]DMSO, 300.13 MHz): d=
0.94 (t, 12H, CH3), 1.31 (m, 8H, CH3CH2), 1.57 (m, 8H, NCH2CH2),
3.16 ppm (m, 8H, NCH2); 13C{1H} NMR (300 K, [D6]DMSO,
75.47 MHz): d=13.4 (s, 4C, CH3), 19.2 (m, 4C, CH2CH3), 23.0 (s, 4C,
NCH2CH2), 57.5 ppm (m, 4C, NCH2); 19F NMR (300 K, [D6]DMSO,
1
53.85 (53.83), H 9.04 (9.38), N 10.47 (10.56); H NMR (300 K, CD3CN,
300.13 MHz): d=0.97 (t, 12H, CH3), 1.35 (m, 8H, CH3CH2), 1.60 (m,
8H, NCH2CH2), 3.08 ppm (m, 8H, NCH2); 13C{1H} NMR (300 K, CD2Cl2,
75.47 MHz): d=13.8 (s, 4C, CH3), 20.1 (s, 4C, CH3CH2), 24.3 (s, 4C,
NCH2CH2), 59.4 ppm (m, 4C, NCH2); 19F NMR (300 K, CD3CN,
1
2
282.40 MHz): d=À54.3 (dt, 2F, cis-PF4(CN)2, JPF =764, JFF =43 Hz),
2
À41.3 (dt, 2F, cis-PF4(CN)2, 1JPF =710, JFF =43 Hz), À31.5 ppm (d,
4F, trans-PF4(CN)2, 1JPF =739 Hz); 31P NMR (300 K, CD3CN,
1
121.49 MHz): d=À183.1 (tt, 1P, cis-PF4(CN)2, 1JPF =767, JPF
=
713 Hz), À170.1 ppm (quin, 1P, trans-PF4(CN)2, 1JPF =740 Hz); IR
282.40 MHz): d=À75.1 (dquin, 1F, 1JPF =762, JFF =56 Hz),
2
À47.1 ppm (dd, 4F, 1JPF =740, JFF =56 Hz); 31P NMR (300 K,
2
~
(258C, ATR, 32 scans): n=550 (s), 559 (s), 650 (m), 716 (s), 737 (m),
1
785 (s), 812 (s), 827 (s), 881 (w), 926 (w), 984 (w), 1036 (w), 1066
(w), 1111 (w), 1171 (w), 1242 (w), 1319 (w), 1348 (w), 1359 (w), 1383
(w), 1473 (m), 2204 (m), 2877 (m), 2937 (m), 2964 cmÀ1 (m); Raman
[D6]DMSO, 121.49 MHz): d=À158.4 ppm (dquin, 1P, PF5(CN), JPF
=
1
~
740, JPF =762 Hz); IR (258C, ATR, 32 scans): n=552 (s), 557 (s), 586
(w), 652 (w), 692 (m), 737 (m), 812 (s), 827 (s), 883 (w), 926 (w),
1034 (w), 1066 (w), 1111 (w), 1167 (w), 1242 (w), 1321 (w), 1348 (w),
1385 (w), 1473 (m), 2212 (w), 2879 (m), 2937 (m), 2966 cmÀ1 (m);
~
(258C, 6 mW, 8 scans): n=257 (1), 413 (1), 438 (1), 647 (1), 876 (1),
899 (1), 922 (1), 1053 (1), 1106 (1), 1317 (1), 1446 (2), 2205 (5), 2873
(8), 2935 (10), 2970 cmÀ1 (7).
~
Raman (258C, 6 mW, 4 scans): n=270 (3), 353 (1), 437 (2), 561 (1),
578 (1), 607 (1), 889 (2), 913 (2), 934 (1), 1040 (1), 1044 (1), 1066 (2),
1075 (2), 1118 (3), 1161 (1), 1329 (2), 1366 (1), 1458 (4), 1469 (3),
2222 (3), 2753 (1), 2883 (8), 2945 (10), 2981 cmÀ1 (6).
Synthesis of [nBu4N][PF3(CN)3]
[nBu4N][PF6] (1.00 g, 2.59 mmol), PCl5 (5 mol%, 31 mg, 0.15 mmol)
and Me3SiCN (2.6 g, 25.6 mmol) were stirred under argon atmos-
phere at ambient temperature for 19 h. After isolating the product
as described in the general procedure and drying in vacuo 1.00 g
(95%, 2.45 mmol) of [nBu4N][PF3(CN)3] was obtained as a light
yellow solid. According to 19F and 31P NMR data the product is
a mixture of 78% of [nBu4N][mer-PF3(CN)3] and 22% of [nBu4N][fac-
PF3(CN)3]; M.p. 69–718C; Tdecomp =3168C; elemental analysis (%)
calcd (found) for C19H36N4PF3 (408.48 gmolÀ1): C 55.87 (55.65), H
General procedure for the Lewis-acid-catalyzed synthesis of
[nBu4N][PF6Àn(CN)n] (n=1–3)
One equivalent of [nBu4N][PF6] and 5 mol% of a Lewis acid were
filled into a Schlenk flask. Then ten equivalents of Me3SiCN were
added under argon atmosphere via a syringe. According to the sol-
ubility of the Lewis acid a suspension or solution is formed. The re-
action mixture was stirred at ambient temperature or under reflux
for several hours. The exact conditions can be found below. The re-
1
8.88 (9.05), N 13.72 (13.60); H NMR (300 K, [D6]DMSO, 300.13 MHz):
Chem. Eur. J. 2016, 22, 4175 – 4188
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4183
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
d=0.94 (t, 12H, CH3), 1.31 (m, 8H, CH3CH2), 1.57 (m, 8H, NCH2CH2),
3.16 ppm (m, 8H, NCH2); 13C{1H} NMR (300 K, [D6]DMSO,
75.47 MHz): d=13.4 (s, 4C, CH3), 19.2 (m, 4C, CH2CH3), 23.0 (s, 4C,
NCH2CH2), 57.5 ppm (m, 4C, NCH2); 19F NMR (300 K, [D6]DMSO,
282.40 MHz): d=À40.5 (d, 3F, fac-PF3(CN)3, 1JPF =742 Hz), À39.9
6H, CH2CH3), 3.04 (m, 6H, NCH2), 6.85 ppm (br, 1H, NH); 13C{1H}
NMR (300 K, CD2Cl2, 75.47 MHz): d=11.1 (s, 3C, CH3), 17.9 (s, 3C,
1
CH2CH3), 55.9 (s, 3C, NCH2), 127.7 ppm (dquin, 1C, PF5(CN), JCP
=
321, 2JCF =78 Hz); 19F NMR (300 K, CD2Cl2, 282.40 MHz): d=À78.1
2
(dquin, 1F, 1JPF =764, JFF =57 Hz), À48.4 ppm (dd, 4F, 1JPF =742,
(dd, 2F, mer-PF3(CN)3, JFF =35, 1JPF =681 Hz), À8.7 ppm (dt, 1F,
2JFF =57, 2JCF =78 Hz); 31P NMR (300 K, CD2Cl2, 121.49 MHz): d=
À157.8 ppm (dquin, 1P, 1JPF =742, 1JPF =765, 1JCP =321 Hz); IR
2
2
mer-PF3(CN)3, JFF =35, 1JPF =780 Hz); 31P NMR (300 K, [D6]DMSO,
121.49 MHz): d=À219.3 (q, 1P, fac-PF3(CN)3, 1JPF =739 Hz),
(258C, ATR, 64 scans): n=552 (s), 694 (m), 754 (s), 810 (s), 984 (w),
~
À211.3 ppm (dt, 1P, mer-PF2(CN)3, 1JPF =681, 1JPF =780 Hz); IR
1043 (w), 1093 (w), 1242 (w), 1263 (w), 1385 (w), 1412 (w), 1462
(w), 1475 (w), 2212 (w), 2885 (w), 2945 (w), 2978 (w), 3115 (w),
3228 cmÀ1 (w); Raman (258C, 12 mW, 5 scans): 308 (5), 347 (2), 430
(2), 553 (1), 654 (1), 694 (5), 822 (2), 877 (1), 919 (2), 1039 (5), 1091
(1), 1110 (1), 1154 (1), 1314 (1), 1332 (2), 1453 (5), 1464 (4), 2214 (4),
2746 (1), 2886 (10), 2913 (5), 2946 (10), 2983 cmÀ1 (9).
~
(258C, ATR, 32 scans): n=529 (m), 551 (s), 595 (m), 644 (m), 687 (s),
740 (m), 785 (s), 814 (m), 834 (s), 846 (m), 878 (m), 1006 (w), 1030
(w), 1068 (w), 1108 (w), 1152 (w), 1284 (w), 1348 (w), 1382 (m),
1463 (m), 1485 (m), 2197 (w), 2209 (w), 2879 (m), 2938 (m),
2967 cmÀ1 (m); Raman (3 mW, 258C, 4 scans): n=178 (2), 202 (4),
~
235 (1), 264 (2), 373 (1), 407 (1), 465 (1), 538 (1), 562 (1), 604 (1),
653 (4), 799 (1), 885 (2), 918 (2), 1015 (1), 1063 (2), 1117 (1), 1141
(1), 1159 (1), 1328 (2), 1458 (3), 1468 (3), 1489 (1), 2205 (3), 2215
(10), 2755 (1), 2886 (7), 2934 (6), 2951 (8), 2983 cmÀ1 (5).
Synthesis of [nPr3NH][PF4(CN)2]
[nPr3NH][PF6] (1.84 g, 6.36 mmol) and Me3SiCN (6.3 g, 64 mmol)
were stirred under argon atmosphere at 608C for 6 h. After remov-
ing all volatile compounds in vacuo the remaining yellow oil was
suspended in water (20 mL) and aqueous H2O2 (8 mL, 30 wt%) and
the suspension stirred overnight at ambient temperature. The
product was extracted with CH2Cl2 (2”30 mL). The combined or-
ganic phases were dried over anhydrous Na2SO4 and filtered. After
removing the solvent and drying the oil in vacuo, 1.66 g (86%,
5.47 mmol) of [nPr3NH][PF4(CN)2] was obtained. According to 19F
and 31P NMR spectra the product is a mixture of 87% of [nPr3NH]
[cis-PF4(CN)2] and 13% of [nPr3NH][trans-PF4(CN)2]. M.p. À13 to
108C; Tdecomp =2108C; elemental analysis (%) calcd (found) for
C11H22N3PF4 (303.28 gmolÀ1): C 43.56 (43.35), H 7.31 (7.21), N 13.86
Synthesis of [nBu4N][PF2(CN)4]
[Ph3C][PF6] (556 mg, 1.43 mmol) was dissolved in CH2Cl2 (3 mL),
and Me3SiCN (1.42 g, 14 mmol) was added dropwise via a syringe.
The resulting brown solution was stirred at ambient temperature
for 90 min. Then [nBu4N]Cl (397 mg, 1.43 mmol) dissolved in CH2Cl2
(3 mL) was added. After 10 min of further stirring, all volatile com-
pounds were removed in vacuo. The obtained brown oil was
mixed with H2O2 (2 mL, 20 mmol, 30 wt%). The suspension was
stirred at 708C for 1 h and decanted. The remaining yellow sub-
stance was washed seven times with hot n-hexane (5 mL) and
dried in vacuo at 508C to yield 101 mg (17%, 0.24 mmol) of
1
(13.89); H NMR (300 K, CD3CN, 300.13 MHz): d=0.96 (t, 9H, CH3),
1
[nBu4N][PF2(CN)4]; M.p. 648C; H NMR (300 K, CD3CN, 300.13 MHz):
1.68 (m, 6H., CH2CH3), 3.02 (m, 6H, NCH2), 6.61 ppm (br, 1H, NH);
13C{1H} NMR (300 K, CD2Cl2, 75.67 MHz): d=11.1 (s, 3C, CH3), 18.0 (s,
3C, CH2CH3), 55.8 (s, 3C, NCH2), 128.9 ppm (dddt, 2C, cis-PF4(CN)2,
1JCP =248, 2JCF =53, 2JCF =41, 2JCF =37 Hz); 19F NMR (300 K, CD3CN,
d=0.96 (t, 12H, CH3), 1.34 (m, 8H, CH3CH2), 1.59 (m, 8H, CH2CH2N),
3.07 ppm (t, 8H, NCH2); 13C{1H} NMR (300 K, CD3CN, 62.90 MHz):
d=13.8 (s, 4C, CH3), 20.2 (m, 4C, CH2CH3), 24.2 (s, 4C, NCH2CH2),
59.4 (m, 4C, NCH2), 125.2 (dt, 2C, 1JCP =220, 2JCF =67 Hz),
282.40 MHz): d=À54.2 (dt, 2F, cis-PF4(CN)2, 1JPF =766, JFF =44,
2
1
2
2
128.1 ppm (dt, 2C, JCP =144, JCF =39 Hz); 19F NMR (300 K, CD3CN,
2JCF =42, 2JCF =37 Hz), À41.1 (dt, 2F, cis-PF4(CN)2, 1JPF =714, JFF =
282.40 MHz): d=À6.1 ppm (d, 2F, cis-PF2(CN)4, 1JPF =730 Hz);
44, JCF =53 Hz), À31.3 ppm (d, 4F, trans-PF4(CN)2, JPF =740, JCF
=
2
1
2
31P NMR (300 K, CD3CN, 96.29 MHz): d=À269.1 ppm (t, 1P, cis-
71 Hz); 31P NMR (300 K, CD3CN, 121.49 MHz): d=À170.8 (quin, 1P,
1
1
1
~
PF2(CN)4, JPF =730 Hz); IR (258C, ATR, 32 scans): n=542 (s), 569 (s),
trans-PF4(CN)2, JPF =740 Hz), À183.3 ppm (tt, 1P, cis-PF4(CN)2, JPF
=
1
1
~
674 (s), 743 (m), 764 (s), 774 (s), 792 (s), 884 (m), 1007 (w), 1027
(w), 1065 (w), 1107 (w), 1149 (w), 1380 (m), 1469 (m), 1483 (m),
1680 (w), 2193 (m), 2202 (m), 2877 (m), 2938 (w), 2966 cmÀ1 (m);
Raman (258C, 65 mW, 4 scans): 218 (6), 255 (10), 392 (3), 402 (2),
436 (1), 473 (4), 514 (1), 524 (2), 574 (10), 800 (1), 880 (2), 914 (6),
1005 (1), 1040 (2), 1056 (4), 1113 (1), 1136 (3), 1155 (2), 1328 (4),
1454 (5), 1463 (4), 2197 (4), 2206 (10), 2217 (2), 2880 (2), 2941 (3),
2980 cmÀ1 (1).
765, JPF =714, JPC =250 Hz); IR (258C, ATR, 32 scans): n=548 (s),
561 (s), 652 (m), 708 (s), 754 (s), 787 (s), 814 (s), 984 (w), 1041 (w),
1093 (w), 1169 (w), 1242 (w), 1269 (w), 1389 (w), 1429 (w), 1462
(w), 1473 (m), 2204 (w), 2808 (w), 2885 (w), 2945 (w), 2978 (w),
3082 cmÀ1 (w).
Synthesis of [nPr3NH][PF3(CN)3]
[nPr3NH][PF6] (2.42 g, 8.37 mmol), PCl5 (5 mol%, 87 mg, 0.42 mmol),
and Me3SiCN (8.33 g, 84 mmol) were stirred under argon atmos-
phere at ambient temperature for 22 h. The solution turned quickly
brown. After removing the excess Me3SiCN and formed Me3SiF, the
brown oil was mixed with water (20 mL) and aqueous H2O2 (7 mL,
30 wt%). The resulting suspension was stirred at ambient tempera-
ture overnight. The product was extracted with CH2Cl2 (2”30 mL).
The combined organic phases were dried over anhydrous Na2SO4
and filtered. After removing the solvent and drying the oil in
vacuo, 2.13 g (82%, 6.86 mmol) of [nPr3NH][PF3(CN)3] was obtained.
According to 19F and 31P NMR spectra the product is a mixture of
95% of [nPr3NH][mer-PF3(CN)3] and 5% of [nPr3NH][fac-PF3(CN)3]
M.p. À28C; Tdecomp =2108C; elemental analysis (%) calcd (found) for
C12H22N4PF3 (310.30 gmolÀ1): C 46.45 (46.22), H 7.15 (7.12), N 18.06
(17.37); 1H NMR (300 K, CD2Cl2, 250.13 MHz): d=1.06 (t, 9H, CH3),
1.78 (m, 6H, CH2CH3), 3.07 (m, 6H, NCH2), 6.80 ppm (br, 1H, NH);
Synthesis of [nPr3NH][PF5(CN)]
[nPr3NH][PF6] (1.65 g, 5.70 mmol) and Me3SiCN (5.65 g, 57 mmol)
were stirred under argon atmosphere at ambient temperature for
20 h. The excess Me3SiCN and formed Me3SiF were removed in
vacuo. The resulting white solid was mixed with distilled water
(20 mL) and aqueous H2O2 (7 mL, 30 wt%, 70 mmol). After stirring
the suspension overnight at ambient temperature the product was
extracted with CH2Cl2 (2”40 mL). The combined organic phases
were dried over anhydrous Na2SO4 and filtered. After removing the
solvent the remaining solid was dried in vacuo to obtain 1.57 g
(93%, 5.30 mmol) of [nPr3NH][PF5(CN)]. M.p. 161–1648C; Tdecomp
=
2108C; elemental analysis (%) calcd (found) for C10H22N2PF5
(296.26 gmolÀ1): C 40.54 (40.31), H 7.48 (7.66), N 9.46 (9.90);
1H NMR (300 K, CD2Cl2, 300.13 MHz): d=1.02 (t, 9H, CH3), 1.75 (m,
Chem. Eur. J. 2016, 22, 4175 – 4188
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ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
13C{1H} NMR (300 K, CD2Cl2, 62.90 MHz): d=11.0 (s, 3C, CH3), 17.9 (s,
241 (2), 244 (2), 430 (1), 461 (1), 508 (2), 584 (2), 677 (6), 693 (6),
2233 cmÀ1 (7).
1
3C, CH2CH3), 55.9 (s, 3C, NCH2), 125.6 (ddt, 2C, mer-PF3(CN)3, JCP
260, JCF =80, JCF =53 Hz), 129.2 ppm (ddt, 1C, mer-PF3(CN)3, JCP
=
=
2
2
1
2
2
180, JCF =35, JCF =19 Hz); 19F NMR (300 K, CDCl3, 282.40 MHz): d=
Synthesis of K[PF3(CN)3]
À41.6 (d, 3F, fac-PF3(CN)3, 1JPF =751, 2JCP =42 Hz), À39.7 (dd, 2F,
mer-PF3(CN)3, 1JPF =690, JFF =35 Hz), À10.0 ppm (dt, 1F, mer-
K[PF6] (2.0 g, 10.87 mmol), [Ph3C][PF6] (0.21 g, 0.54 mmol), and
Me3SiCN (8.63 g, 87 mmol) were stirred under argon atmosphere at
608C for 3 h. The excess Me3SiCN and any Me3SiF were removed in
vacuo to give a brown crystalline residue, which was dissolved in
aqueous H2O2 (8 mL, 80 mmol, 30 wt%). The suspension was
stirred at 708C for 1 h and filtered. The filtrate was dried in vacuo.
Then the solid was washed three times with benzene and suspend-
ed in CH3CN and filtered. After removing the solvent the obtained
white solid was dried at 1008C in vacuo to yield 1.81 g (81%,
8.82 mmol) of K[PF3(CN)3]. The product is a mixture of 89% of
K[mer-PF3(CN)3] and 11 % of K[fac-PF3(CN)3] according to 19F and
31P NMR studies. M.p. 1648C (decomp); elemental analysis (%)
calcd (found) for KPF3C3N3 (205.12 gmolÀ1): C 17.57 (17.34), N 20.49
(20.96); 13C{1H} NMR (300 K, D2O, 62.86 MHz): d=124.6 (ddt, 2C,
PF3(CN)3, 1JCP =262, 2JCF =80, 2JCF =54 Hz), 127.7 ppm (ddt, 1C,
PF3(CN)3, 1JCP =183, 2JCF =35, 2JCF =19 Hz); 19F NMR (300 K, D2O,
282.40 MHz): d=À40.6 (d, 3F, fac-PF3(CN)3, 1JPF =748 Hz), À39.6
2
PF3(CN)3, 1JPF =788, 2JFF =35 Hz); 31P NMR (300 K, CD2Cl2,
101.25 MHz): d=À224.2 (q, 1P, fac-PF3(CN)3, 1JPF =750 Hz),
À209.9 ppm (dt, 1P, mer-PF2(CN)3, 1JPF =687, 1JPF =783, 1JCP =260,
1JCP =180 Hz); IR (258C, ATR, 32 scans): n=552 (s), 596 (m), 640 (m),
~
683 (s), 754 (m), 793 (s), 829 (s), 982 (w), 1041 (w), 1093 (w), 1171
(w), 1240 (w), 1389 (w), 1427 (w), 1462 (w), 1473 (m), 2199 (w),
2208 (w), 2806 (w), 2885 (w), 2945 (w), 2976 (w), 3093 cmÀ1 (w).
Synthesis of K[PF5(CN)]
[nPr3NH][PF5(CN)] (1.12 g, 3.78 mmol) dissolved in CH2Cl2 (15 mL)
was added to an aqueous solution of KOH (0.21 g in 5 mL distilled
water). After stirring the reaction mixture for 3 h at ambient tem-
perature all volatile compounds were removed in vacuo. The re-
sulting white solid was washed several times with CH2Cl2. The
product was dissolved in CH3CN (10 mL) and the solution filtered
from insoluble impurities. After removing the solvent and drying
the remaining white solid in vacuo, 642 mg (89%, 3.36 mmol) of
K[PF5(CN)] was obtained. M.p. 1548C; Tdecomp =2218C; elemental
analysis (%) calcd (found) for KPF5CN (191.08 gmolÀ1): C 6.29 (6.41),
N 7.33 (6.50); 13C{1H} NMR (300 K, CD3CN, 75.47 MHz): d=127.2
2
(dd, 2F, mer-PF3(CN)3, 1JPF =681, JFF =35 Hz), À8.8 ppm (dt, 1F,
2
mer-PF3(CN)3, 1JPF =782, JFF =35 Hz); 31P NMR (300 K, D2O,
1
121.49 MHz): d=À210.7 (dt, 1P, mer-PF3(CN)3, 1JPF =683, JPF
=
780 Hz), À224.8 ppm (q, 1P, fac-PF3(CN)3, 1JPF =744 Hz); IR (258C,
~
ATR, 32 scans): n=528 (m), 555 (s), 600 (w), 638 (s), 648 (s), 687 (s),
793 (s), 845 (m), 2216 (w), 2227 cmÀ1 (w); Raman (258C, 12 mW, 5
1
2
(dquin, 1C, PF5(CN), JCP =328, JCF =77 Hz); 19F NMR (300 K, CD3CN,
~
scans): n=185 (2), 205 (10), 232 (1), 397 (1), 413 (2), 456 (1), 503
1
2
282.40 MHz): d=À77.6 (dquin, 1F, PF5(CN), JPF =756, JFF =53 Hz),
(1), 531 (3), 553 (1), 558 (1), 644 (8), 2212 (3), 2226 cmÀ1 (9).
À48.9 ppm (dd, 4F, PF5(CN), 1JPF =737, JFF =53, 2JCF =78 Hz);
2
31P NMR (300 K, CD3CN, 121.49 MHz): d=À158.4 ppm (dquin, 1P,
PF5(CN), 1JPF =756, 1JPF =737, 1JCP =322 Hz); IR (258C, ATR, 32
Synthesis of Ag[PF3(CN)3]
À1
~
scans): n552 (s), 588 (w), 696 (s), 785 (s), 827 (s), 2231 cm (w);
AgNO3 (0.730 g, 4.30 mmol) in distilled water (10 mL) was added to
a stirred solution of K[PF3(CN)3] (0.858 g, 4.18 mmol) in distilled
water (15 mL) at ambient temperature with exclusion of light. A
white precipitate formed. After 30 min of stirring the solid was fil-
tered and washed with water (3”15 mL). After drying in vacuo at
1008C 0.701 g (2.56 mmol, 61%) of Ag[PF3(CN)3] was obtained.
Ag[PF3(CN)3] is a mixture of 94% of Ag[mer-PF3(CN)3] and 6% of
~
Raman (258C, 23 mW, 3 scans): n=184 (3), 343 (2), 349 (1), 438 (1),
464 (1), 554 (1), 572 (3), 702 (10), 807 (1), 2229 cmÀ1 (7).
Synthesis of K[trans-PF4(CN)2]
[Ph3C][PF6] (482 mg, 1.24 mmol) was dissolved in CH2Cl2 (5 mL).
This solution was cooled to À408C and Me3SiCN (1.23 g,
12.4 mmol) was added dropwise via a syringe. The resulting color-
less solution was warmed to À308C and stirred for 30 min. Then
KOtBu (144 mg, 1.28 mmol) dissolved in THF (4 mL) was added.
The reaction mixture was warmed to ambient temperature and all
volatile compounds were removed in vacuo. The obtained white
solid was washed with benzene (3”8 mL). The remaining solid was
suspended in H2O and filtered. The filtrate was dried in vacuo.
Then the solid was suspended in CH3CN and collected by filtration.
After removing the solvent the obtained white solid substance was
dried at 508C in vacuo to yield 182 mg (74%, 0.92 mmol) of
K[PF4(CN)2]. According to 19F and 31P NMR studies, the product is
a mixture of 7% of K[cis-PF4(CN)2] and 93% of K[trans-PF4(CN)2];
M.p. 227–2358C; Tdecomp =2388C; elemental analysis (%) calcd
(found) for KPF4C2N2 (198.10 gmolÀ1): C 12.13 (12.48), N 14.14
(13.20); 13C{1H} NMR (300 K, [D6]DMSO, 75.47 MHz): d=124.3 ppm
Ag[fac-PF3(CN)3] according to 19F and 31P NMR studies; Tdecomp
=
2278C; elemental analysis (%) calcd (found) for AgPF3C3N3
(273.89 gmolÀ1): C 13.16 (13.15), N 15.34 (14.68); 13C{1H} NMR
(300 K, CD3CN, 62.90 MHz): d=126.1 (ddt, PF3(CN)3, 2C, 2JCF =53,
2JCF =80, 1JCP =260 Hz), 129.8 ppm (ddt, PF3(CN)3, 1C, 2JCF =19,
2JCF =35, 1JCP =180 Hz); 19F NMR (300 K, CD3CN, 282.40 MHz): d=
1
2
À10.0 (dt, 1F, mer-PF3(CN)3, JPF =779 Hz), JFF =34 Hz), À40.01 (dd,
2
2F, mer-PF3(CN)3, 1JPF =680 Hz), JFF =34 Hz), À41.7 (d, 3F, fac-
PF3(CN)3, 1JPF =741 Hz); 31P NMR (300 K, CD3CN, 121.49 MHz): d=
1
1
1
1
À210.6 (dt, 1P, mer-PF3(CN)3, JPF =682, JPF =780, JCP =260, JCP
=
179 Hz), 225.1 ppm (q, 1P, fac-PF3(CN)3, 1JPF =740 Hz); IR (258C,
~
ATR, 32 scans): n=550 (s), 657 (s), 682 (s), 800 (s), 854 (m), 2234
(w), 2249 cmÀ1 (w); Raman (258C, 12 mW, 5 scans): 217 (3), 233 (1),
372 (1), 398 (1), 434 (1), 480 (2), 501 (1), 525 (3), 548 (1), 658 (6),
791 (1), 2238 (10), 2249 cmÀ1 (7).
(dquin, 2C, trans-PF4(CN)2), JCP =320, JCF =71 Hz); 19F NMR (300 K,
1
2
Synthesis of Li[PF4(CN)2]·2CH3CN
1
[D6]DMSO, 282.40 MHz): d=À52.5 (dt, 2F, cis-PF4(CN)2, JPF
=
1
767 Hz), À40.4 (dt, 2F, cis-PF4(CN)2, JPF =713 Hz), À30.4 ppm (d, 2F,
[Ph3C][PF6] (945 mg, 2.43 mmol) was dissolved in CH2Cl2 (8 mL).
The solution was cooled to À408C and Me3SiCN (2.38 g, 24 mmol)
was added dropwise via a syringe. The resulting colorless solution
was warmed to À308C and stirred for 30 min. Then LiBr (211 mg,
2.43 mmol) dissolved in Et2O (5 mL) was added. The reaction mix-
ture was warmed to ambient temperature and all volatile com-
trans-PF4(CN)2,
1JPF =740 Hz);
31P NMR
(300 K,
[D6]DMSO,
121.49 MHz): d=À168.9 (quin, 1P, trans-PF4(CN)2, 1JPF =740 Hz),
1
À183.3 ppm (quin, 1P, cis-PF4(CN)2, JPF =767 Hz); IR (258C, ATR, 64
~
scans): n=548 (s), 598 (m), 696 (s), 785 (s), 797 (s), 864 (m),
2237 cmÀ1 (w); Raman (258C, 3 mW, 5 scans): n=200 (2), 214 (10),
~
Chem. Eur. J. 2016, 22, 4175 – 4188
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4185
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
pounds were removed in vacuo. The remaining white solid was
dissolved in CH3CN (1 mL) and precipitated by addition of benzene
(10 mL). After filtration and drying in vacuo 471 mg (78%,
1.90 mmol) of (Li[PF4(CN)2]·2CH3CN was obtained. The product is
a mixture of about 7% of Li[cis-PF4(CN)2]·2CH3CN and 93% of Li-
[trans-PF4(CN)2]·2CH3CN according to 19F and 31P NMR spectrosco-
py; TGA/DSC (5 KminÀ1): Dm=À32.7% (À2CH3CN, 120–1508C),
À61% (decomp, 2608C); elemental analysis (%) calcd (found) for
C6H6N4LiPF4 (248.05 gmolÀ1): C 29.05 (28.31), H 2.44 (2.34), N 22.59
2.07 ppm (s, 6H, CH3CN); 13C{1H} NMR (300 K, CD3CN, 62.89 MHz):
d=126.5 (ddt, 2C, mer-PF3(CN)3, 1JPC =261, 2JFC =80, 2JFC =53 Hz),
1
2
2
129.6 ppm (ddt, 1C, mer-PF3(CN)3, JPC =180, JFC =34, JFC =19 Hz);
19F NMR (300 K, CD3CN, 282.40 MHz): d=À41.7 (d, 3F, fac-PF3(CN)3,
2
1JPF =740 Hz), À40.0 (dd, 2F, mer-PF3(CN)3, 1JPF =680, JFF =34 Hz),
2
À9.99 ppm (dt, 1F, mer-PF3(CN)3, 1JPF =779, JFF =34 Hz); 31P NMR
(300 K, D2O, 121.50 MHz): d=À210.4 ppm (dt, 1P, mer-PF3(CN)3,
1
1
1JPF =783, JPF =687, JPC =260 Hz);. IR (258C, ATR, 32 scans): n=528
(m), 557 (m), 656 (s), 681 (s), 700 (s), 798 (s), 852 (s), 933 (w), 1038
(w), 1373 (w) 1412 (w), 1443 (w), 2247 (w), 2280 (w), 2308 (w), 2949
~
(21.81); 13C{1H} NMR (300 K, D2O, 75.47 MHz): d=0.3 (s, 2C, CH3CN),
1
(w), 3012 cmÀ1 (w); Raman (258C, 12 mW, 5 scans): n=215 (4), 232
~
118.7 (s, 2C, CH3CN), 123.6 ppm (dquin, 2C, trans-PF4(CN)2, JPC
=
2
320, JCF =71 Hz); 19F NMR (300 K, D2O, 282.40 MHz): d=À53.7 (dt,
(1), 387 (1), 507 (1), 528 (1), 554 (1), 655 (3), 805 (1), 932 (1), 1371
(1), 2244 (10), 2279 (2), 2309 (1), 2948 cmÀ1 (4).
1
2F, cis-PF4(CN)2, 1JPF =767 Hz), À40.5 (dt, 2F, cis-PF4(CN)2, JPF
=
716 Hz), À30.8 ppm (d, 4F, trans-PF4(CN)2, 1JPF =740, 2JFC =71 Hz);
31P NMR (300 K, D2O, 121.49 MHz): d=À170.9 ppm (quin, 1P, trans-
1
1
General procedure for the synthesis of EMIm[PF6Àn(CN)n]
(n=1, 2)
~
PF4(CN)2, JPF =740, JPC =320 Hz); IR (258C, ATR, 32 scans): n=550
(m), 600 (w), 700 (s), 721 (s), 766 (m), 787 (m), 843 (s), 935 (w), 1036
(w), 1373 (w), 1427 (w), 2246 (w), 2281 (m), 2308 (w), 2947 (w),
An equimolar amount of EMImBr in CH2Cl2 was added at to a stirred
solution of potassium or lithium cyanido(fluorido)phosphate in
water at ambient temperature. After stirring for 1 h at ambient
temperature the phases were separated. The aqueous phase was
washed with CH2Cl2. The combined organic phases were washed
twice with water, dried over anhydrous Na2SO4, and filtered. The fil-
trate was concentrated on a rotary evaporator. The obtained color-
less oil was dried in vacuo at 808C for 20 h.
3009 cmÀ1 (w); Raman (258C, 23 mW, 4 scans): n=219 (6), 387 (4),
~
506 (1), 692 (5), 930 (2), 1367 (2), 2246 (10), 2279 (4), 2307 (2), 2944
(8), 3006 cmÀ1 (1).
Synthesis of Li[cis-PF4(CN)2]·2CH3CN
Li[PF6] (0.363 g, 2.38 mmol), [Ph3C][PF6] (5 mol%, 47 mg,
0.12 mmol), and Me3SiCN (2.38 g, 24 mmol) were stirred under
argon atmosphere at ambient temperature for 15 h. The excess
Me3SiCN and any Me3SiF were removed in vacuo to give a white
crystalline residue, which was dissolved in CH3CN (1 mL) and pre-
cipitated by addition of benzene (10 mL). After filtration and
drying in vacuo, 496 mg (84%, 2.00 mmol) of Li[PF4(CN)2]·2CH3CN
was obtained. The product is a mixture of around 96% of Li[cis-
PF4(CN)2]·2CH3CN and 4% of Li[trans-PF4(CN)2]·2CH3CN according
to 19F and 31P NMR studies; elemental analysis (%) calcd (found) for
C6H6N4LiPF4 (248.05 gmolÀ1): C 29.05 (29.09), H 2.44 (2.27), N 22.59
(21.68); 1H NMR (300 K, [D6]DMSO, 300.13 MHz): d=2.04 ppm (s,
6H, CH3CN); 13C{1H} NMR (300 K, [D6]DMSO, 75.47 MHz): d=1.2 (s,
2C, CH3CN), 118.1 (s, 2C, CN), 127.7 ppm (dddt, 2C, cis-PF4(CN)2,
1JPC =247, 2JCF =53, 2JCF =41, 2JCF =37 Hz); 19F NMR (300 K, D2O,
EMIm[PF5(CN)]: Yield: 94% (1.07 g, 4.07 mmol). M.p. À18 to
À138C; Tdecomp =3268C; elemental analysis (%) calcd (found) for
C7H11N3PF5 (263.15 gmolÀ1): C 31.95 (32.20), H 4.21 (4.22), N 15.97
1
(15.58); H NMR (300 K, CD3CN, 300.13 MHz): d=1.46 (t, 3H, CH3),
3.82 (s, 3H, NCH3), 4.17 (q, 2H, NCH2), 7.32 (m, 1H, EtNCH), 7.37 (m,
1H, MeNCH), 8.39 ppm (s, 1H, NCHN); 13C{1H} NMR (300 K, CD3CN,
75.47 MHz): d=15.5 (s, 1C, NCH2CH3), 36.9 (s, 1C, NCH3), 45.9 (s,
1C, NCH2), 123.1 (s, 1C, EtNCH), 124.7 (s, 1C, MeNCH), 127.5 (dquin,
1C, PF5(CN) 1JCP =327, 2JCF =77 Hz), 136.6 ppm (br, 1C, NCHN);
19F NMR (300 K, CD3CN, 282.40 MHz): d=À77.5 (dquin, 1F, PF5(CN),
2
1
2
1JPF =758, JFF =54 Hz), À48.8 ppm (dd, 4F, PF5(CN), JPF =738, JFF =
54, 2JCF =77 Hz); 31P NMR (300 K, CD3CN, 300.13 MHz): d=
1
1
1
À158.3 ppm (dquin, 1P, PF5(CN), JPF =756, JPF =739, JCP =328 Hz);
1
2
~
IR (258C, ATR, 64 scans,): n=552 (s), 598 (w), 621 (m), 646 (m), 692
282.40 MHz): d=À53.7 (dt, 2F, cis-PF4(CN)2, JPF =765, JFF =45 Hz),
2
À40.4 (dt, 2F, cis-PF4(CN)2, 1JPF =713, JFF =45 Hz), À30.8 ppm (d,
(s), 744 (s), 802 (s), 960 (w), 1034 (w), 1090 (w), 1111 (w), 1167 (s),
1336 (w), 1358 (w), 1392 (w), 1429 (w), 1454 (w), 1470 (w), 1574
(m), 2212 (w), 2991 (w), 3124 (w), 3172 cmÀ1 (w).
4F, trans-PF4(CN)2, 1JPF =740 Hz); 31P NMR (300 K, [D6]DMSO,
1
121.50 MHz): d=À183.1 ppm (tt, 1P, cis-PF4(CN)2, 1JPF =765, JPF
=
713 Hz); IR (258C, ATR, 32 scans): 550 (s), 567 (s), 656 (s), 719 (m),
791 (s), 814 (s), 935 (w), 1038 (w), 1375 (w), 1415 (w), 2237 (w),
2283 (m), 2312 (w), 2951 cmÀ1 (w); Raman (258C, 3 mW, 4 scans):
EMIm[PF4(CN)2]: Yield: 95% (3.10 g, 11.47 mmol). M.p. À34 to
À308C; Tdecomp =2768C; elemental analysis (%) calcd (found) for
C8H11N4PF4 (270.17 gmolÀ1): C 35.57 (35.61), H 4.10 (3.97), N 20.74
(20.59); 1H NMR (300 K, CD2Cl2, 300.13 MHz): d=1.45 (t, 3H, CH3),
3.86 (s, 3H, NCH3), 4.16 (q, 2H, NCH2), 7.23 (m, 1H, EtNCH), 7.26 (m,
1H, MeNCH), 8.27 ppm (s, 1H, NCHN); 13C{1H} NMR (300 K, CD3CN,
75.47 MHz): d=15.0 (s, 1C, NCH2CH3), 36.6 (s, 1C, NCH3), 46.7 (s,
1C, NCH2), 122.5 (s, 1C, EtNCH), 124.1 (s, 1C, MeNCH), 124.9 (dquin,
2C, trans-PF4(CN)2, 1JCP =318, 2JCF =70 Hz), 128.1 (dddt, 2C, cis-
~
n=367 (1), 387 (2), 514 (1), 549 (1), 563 (1), 658 (3), 830 (1), 932 (3),
1373 (3), 2235 (9), 2282 (8), 2312 (2), 2948 cmÀ1 (10).
Synthesis of Li[PF3(CN)3]
Lithium bromide (0.103 g, 1.15 mmol) in distilled water (10 mL)
2
was added to
a
stirred solution of Ag[PF3(CN)3] (0.316 g,
PF4(CN)2, 1JCP =248, 2JCF =37, JCF =41, 2JCF =53 Hz), 135.0 ppm (br,
1.15 mmol) in acetonitrile (10 mL) at ambient temperature. A
greenish precipitate of AgBr formed. After 30 min of stirring AgBr
was filtered off. The filtrate was dried on a rotary evaporator. The
obtained solid was dissolved in distilled water (10 mL) and the so-
lution filtered. After prolonged drying in vacuo and recrystallization
from acetonitrile/benzene, 263 mg (89%, 1.03 mmol) of
Li[PF3(CN)3]·2CH3CN was obtained. The product is a mixture of
94% of Li[mer-PF3(CN)3]·2CH3CN and 6% of Li[fac-PF3(CN)3]·2CH3CN
according to 19F and 31P NMR studies; elemental analysis (%) calcd
(found) for C7H6N5LiPF3 (255.07 gmolÀ1): C 32.96 (33.06), H 2.37
(2.57), N 27.46 (26.97); 1H NMR (300 K, D2O, 250.13 MHz): d=
1C, NCHN); 19F NMR (300 K, CD3CN, 282.40 MHz): d=À54.2 (dt, 2F,
2
cis-PF4(CN)2, 1JPF =766, JFF =45, 2JCF =41, 2JCF =37 Hz), À41.2 (dt,
1
2
2
2F, cis-PF4(CN)2, JPF =713, JFF =45, JCF =53 Hz), À31.3 ppm (d, 4F,
trans-PF4(CN)2, 1JPF =735, 2JCF =71 Hz); 31P NMR (300 K, CD2Cl2,
101.25 MHz): d=À183.0 (tt, 1P, cis-PF4(CN)2, 1JPF =713, 1JPF =766,
1
1JCP =247 Hz), À170.8 ppm (q, 1P, trans-PF4(CN)2, 1JPF =740, JCP
=
~
317 Hz); IR (258C, ATR, 32 scans): n=550 (s), 561 (s), 598 (w), 621
(s), 646 (s), 710 (s), 744 (s), 783 (s), 810 (s), 960 (w), 1032 (w), 1090
(w), 1111 (w), 1167 (s), 1337 (w), 1392 (w), 1429 (w), 1454 (w), 1470
(w), 1574 (w), 2204 (w), 2218 (w), 2991 (w), 3124 (w), 3169 cmÀ1
(w).
Chem. Eur. J. 2016, 22, 4175 – 4188
www.chemeurj.org
4186
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
(m), 563 (w), 596 (w), 615 (m), 633 (m), 685 (s), 723 (s), 752 (m), 793
(s), 822 (m), 845 (w), 997 (w), 1028 (w), 1072 (w), 1109 (s), 1165 (w),
1188 (w), 1298 (w), 1315 (w), 1340 (w), 1392 (w), 1439 (m), 1485
(w), 1589 (w), 2194 (w), 2206 (w), 3064 cmÀ1 (w); Raman (258C,
Synthesis of EMIm[PF3(CN)3]
EMIm[PF6] (3.47 g, 13.9 mmol), PCl5 (5 mol%, 145 mg), and
Me3SiCN (13.8 g, 139 mmol) were stirred under argon atmosphere
at ambient temperature for 10 h. After removing all volatile com-
pounds in vacuo the remaining brown oil was mixed with water
(15 mL) and aqueous H2O2 (10 mL, 100 mmol, 30 wt%). The sus-
pension was stirred at 708C for 4 h. After cooling to ambient tem-
perature, the product was extracted with butyl acetate (50 mL).
The butyl acetate layer was separated and the solvent was re-
moved on a rotary evaporator. Prolonged drying of the remaining
yellow oil in vacuo gve 3.58 g (93%, 12.9 mmol) of EMIm[PF3(CN)3].
According to 19F and 31P NMR data the product contains around
~
12 mW, 8 scans: n=251 (3), 291 (1), 525 (1), 614 (2), 632 (1), 680
(2), 1001 (10), 1025 (4), 1099 (2), 1109 (1), 1164 (1), 1578 (1), 1589
(4), 2196 (1), 2205 (2), 3048 (1), 3062 (4), 3077 (1), 3091 cmÀ1 (1).
Acknowledgements
Financial support by the Lonza Group Ltd. (K.S.) is gratefully ac-
knowledged. We also thank the DFG Priority program: Material
synthesis near room temperature (SPP 1708) for financial sup-
port.
87% of EMIm[mer-PF3(CN)3] and 13% of EMIm[fac-PF3(CN)3]; Tglass
=
À358C; M.p. À15 to À98C; Tdecomp =2328C; elemental analysis (%)
calcd (found) for C9H11N5PF3 (277.19 gmolÀ1): C 39.00 (39.23), H
4.00 (4.15), N 25.27 (24.99); 1H NMR (300 K, CD3CN, 300.13 MHz):
d=1.46 (t, 3H, CH3), 3.82 (s, 3H, NCH3), 4.17 (q, 2H, NCH2), 7.32 (m,
1H, EtNCH), 7.37 (m, 1H, Me-N-CH), 8.39 ppm (s, 1H, NCHN);
13C{1H} NMR (300 K, CD3CN, 75.47 MHz): d=15.5 (s, 1C, CH3), 36.9
(s, 1C, NCH3), 45.9 (s, 1C, NCH2), 123.1 (s, 1C, EtNCH), 124.7 (s, 1C,
Keywords: cyanides · homogeneous catalysis · ionic liquids ·
Lewis acids · phosphorus
2
2
1
MeNCH), 126.0 (ddt, 2C, PF3(CN)3, JCF =53, JCF =80, JCP =260 Hz),
129.3 (ddt, 1C, PF3(CN)3, 2JCF =19, 2JCF =36, 1JCP =179 Hz),
136.6 ppm (s, 1C, NCHN); 19F NMR (300 K, CD3CN, 282.40 MHz): d=
[1] K. B. Dillon, A. W. G. Platt, J. Chem. Soc. Dalton Trans. 1982, 1199.
[2] P. J. Chevrier, S. Brownstein, J. Inorg. Nucl. Chem. 1980, 42, 1397–1405.
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À41.6 (d, 3F, fac-PF3(CN)3, 1JPF =743 Hz), À40.1 (dd, 1F, mer-
PF3(CN)3, 1JPF =680 Hz), À9.9 ppm (dt, 2F, mer-PF3(CN)3, JPF
=
1
780 Hz); 31P NMR (300 K, CD3CN, 121.49 MHz): d=À210.4 (dt, 1P,
mer-PF3(CN)3, 1JPF =683, 1JPF =780, 1JPC =260, 1JPC =180 Hz,),
À225.0 ppm (q, 1P, fac-PF3(CN)3, 1JPF =744 Hz); IR (258C, ATR, 32
[7] K. B. Dillon, A. W. G. Platt, T. C. Waddington, J. Chem. Soc. Chem.
Commun. 1979, 889.
~
scans): n=542 (s), 569 (s), 621 (s), 646 (s), 667 (s), 702 (w), 765 (s),
777 (s), 959 (w), 1032 (w), 1088 (w), 1109 (w), 1165 (s), 1336 (w),
1358 (w), 1390 (w), 1429 (w), 1452 (w), 1470 (w), 1574 (w), 2195
(m), 2202 (m), 2947 (w), 2966 (w), 2991 (w), 3120 (w), 3157 cmÀ1
(w).
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Sievert, A. Stoffers, C. Zur Täschler, WO 2014167034A2, 20141016, 2014.
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Synthesis of [Ph4P][PF3(CN)3]
[Ph4P][PF6] (1.01 g, 2.09 mmol), 8 mol% [Ph3C][PF6] (65 mg,
0.17 mmol), and Me3SiCN (2.08 g, 21.0 mmol) were stirred under
argon atmosphere at ambient temperature for 4 h. After removing
the excess Me3SiCN and formed Me3SiF in vacuo the resulting
brown solid was mixed with distilled water (15 mL) and aqueous
H2O2 (5 mL, 30 wt%) and the mixture stirred at 608C for 4 h. After
cooling to ambient temperature the suspension was filtered. The
remaining solid was washed with benzene (3”10 mL) and subse-
quently dissolved in CH2Cl2. After filtration, the organic phase was
dried over anhydrous Na2SO4 and filtered. The filtrate was concen-
trated on a rotary evaporator. Prolonged drying of the remaining
white solid in vacuo at 808C gave 951 mg (90%, 1.88 mmol) of
[Ph4P][PF3(CN)3]. M.p. 2138C; Tdecomp =3178C; elemental analysis
(%) calcd (found) for C27H20N3P2F3 (505.11 gmolÀ1): C 64.16 (64.14),
H 3.99 (3.80), N 8.31 (8.32); 1H NMR (300 K, CD3CN, 300.13 MHz):
d=7.68 (m, 8C, o-CH), 7.73 (m, 8C, m-CH), 7.94 ppm (m, 4C, p-CH);
13C{1H} NMR (300 K, CD3CN, 62.90 MHz): d=118.9 (d, 4C, i-C, JCP
=
1
90 Hz), 126.1 (ddt, PF3(CN)3, 2C, 2JCF =53, 2JCF =80, 1JCP =260 Hz),
2
2
1
129.8 (ddt, PF3(CN)3, 1C, JCF =19, JCF =35, JCP =180 Hz), 131.3 (d,
3
2
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1815.
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3223–3226.
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2012, 134, 17757–17768.
8C, m-CH, JCP =13 Hz), 135.7 (d, 8C, o-CH, JCP =11 Hz), 136.4 ppm
4
(d, 4C, p-CH, JCP =4 Hz); 19F NMR (300 K, CD3CN, 282.40 MHz): d=
À9.8 (dt, 1F, mer-PF3(CN)3, 1JPF =779 Hz), JFF =34 Hz), À40.1 (dd,
2
1
2
2F, mer-PF3(CN)3, JPF =680 Hz), JFF =34 Hz), À41.7 ppm (d, 3F, fac-
PF3(CN)3, 1JPF =741 Hz); 31P NMR (300 K, CD3CN, 121.49 MHz): d=
23.0 (s, 1P, Ph4P, 1JCP =88 Hz, 3JCP =12 Hz), À210.6 (dt, 1P, mer-
1
1
1
1
PF3(CN)3, JPF =681, JPF =778, JPC =261, JPC =176 Hz), À225.3 ppm
1
~
(q, 1P, fac-PF3(CN)3, JPF =742 Hz); IR (258C, ATR, 64 scans): n=550
Chem. Eur. J. 2016, 22, 4175 – 4188
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Full Paper
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Received: November 11, 2015
Published online on February 5, 2016
Chem. Eur. J. 2016, 22, 4175 – 4188
www.chemeurj.org
4188
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim