High-energy-density materials: Synthesis and characterization of N 5+[P(N3)6]-, N5+[B(N3)4]-, N5+[HF2]-·n HF, N5+[BF4]-, N5+[PF6]-, and N5+[SO3F]-

Article abstract of DOI:10.1002/anie.200454242

23 nitrogens and only one phosphorus: The N₅⁺ ion is combined with energetic anions in the form of N₅⁺[P(N ₃)₆]^- and N₅⁺[B(N ₃)₄]^- (see scheme), containing 91 and 96 wt%, respectively, of nitrogen. Also, the thermally unstable compound N ₅HF₂·n HF is prepared by metathesis from N ₅SbF₆ and CsHF₂. Its usefulness as a reagent for the synthesis of new N₅⁺ salts is demonstrated with the preparation of N₅PF₆, N₅BF₄, and N₅SO₃F.

Full text of DOI:10.1002/anie.200454242

Angewandte
Chemie
[
21]
+
ꢀ
Polynitrogen Chemistry
known Lewis acids, the displacement of SbF in N5 [SbF6]
5
by a stronger Lewis acid is also rarely feasible. Therefore, the
development of a more general method for the syntheses of
High-Energy-Density Materials: Synthesis and
+
ꢀ
+
ꢀ
+
Characterization of N [P(N ) ] , N [B(N ) ] ,
N5 compounds is desirable. Furthermore, in the interest of
5
3 6
5
3 4
+
ꢀ
+
ꢀ
+
ꢀ
+
N [HF ] ·nHF, N [BF ] , N [PF ] , and
preparing N5 salts of higher energy content, the combination
5
2
5
4
5
6
+
ꢀ
+
N [SO F] **
of N5 with highly energetic counterions was pursued.
5
3
+
ꢀ
ꢀ
Previous attempts to combine N with either N3 , [ClO ] ,
5
4
ꢀ
ꢀ
[22]
[
NO ] , or [N(NO ) ] had been unsuccessful.
3 2 2
Ralf Haiges,* Stefan Schneider, Thorsten Schroer, and
Karl O. Christe*
ꢀ
While in theory, F abstraction from FN by a strong
5
Lewis acid, such as SbF , could provide a general synthesis for
5
+
N5 salts [Eq. (3)], the required FN precursor is unknown.
5
Dedicated to Professor Herbert Roesky
on the occasion of his 70th birthday
þ
ꢀ
6
FN5 þ SbF ! N ½SbF Š
ð3Þ
5
5
[
23,24]
During the past two decades, polynitrogen containing com-
pounds have received increasing attention as promising
candidates for high energy-density materials (HEDM).
Theoretical studies
stable isomers of FN
results, the predicted lifetimes of these species are only in the
identified at least six vibrationally
but, in accordance with experimental
5
[
1–17]
[
23]
While most of the efforts were devoted to theoretical studies,
nanosecond range.
ꢀ
[18]
+
ꢀ
2
the long-known existence of the stable azide anion (N )
During attempts to prepare N [N(CF ) ] by metathesis
3
5
3
+
ꢀ
+
ꢀ
and the recent syntheses of stable salts of the pentanitrogen
from N5 [SbF ] and Cs [N(CF ) ] in HF solution at ꢀ788C
6
3
2
+
[1–3]
cation (N )
have demonstrated the feasibility of exper-
[Eq. (4)], the expected CsSbF precipitate was formed and
5
6
imentally pursuing polynitrogen-containing materials. The
removed by filtration.
+
only known direct method for preparing N5 compounds is
+
þ
Šꢀ þ Cs ½NðCF
þ
Šꢀ ! Nþ
Šꢀ þ CsSbF
their synthesis from an [N F] salt with HN in HF solution
according to Equation (1).
N
5
½SbF
6
3
Þ
2
5
½NðCF
3
Þ
2
6
#
ð4Þ
2
3
[
1,2]
However, after pumping off all volatile material from the
þ
ꢀ
HF
þ
ꢀ
6
½
N FŠ ½MF Š þ HN ƒ!N ½MF Š þ HF
ð1Þ
filtrate at ꢀ648C, the low-temperature Raman spectrum of
2
6
3
5
the resulting clear liquid residue exhibited only bands
+
attributable to N5 (Figure 1). This finding reminded us of a
This direct synthesis route is restricted by the small
number of [N F] salts available. Except for N FAsF and
+
situation encountered 24 years ago with the metathetical
reaction of NF SbF and CsF in HF [Eq. (5)].
2
2
6
[
19]
[20]
N FSbF and reports on unstable N FBF
and N FPF6
4
6
2
6
2
4
2
+
salts, no other [N F] compounds have been reported.
2
þ
4
ꢀ
NF ½SbF Š þ CsF þ ðn þ 1Þ HF ! NF HF ꢁ n HF þ CsSbF #
6
4
2
6
+
Other N5 salts can be prepared by an indirect method
using metathetical reactions [Eq. (2)].
ð5Þ
[
3]
þ
ꢀ
þ
ꢀ
þ
ꢀ
þ
ꢀ
6
N ½SbF Š þ M Y ! M Y þ M ½SbF Š
#
ð2Þ
5
6
5
For a successful metathetical reaction, each ion must be
compatible with the solvent, and both starting materials and
one of the products must be highly soluble, while the second
reaction product must have low solubility. Because of its
highly oxidizing nature, N SbF is compatible with only a
5
6
limited number of solvents, for example, HF, SO and CHF ,
2
3
thus severely restricting the general usefulness of the
metathetical approach. Because SbF is among the strongest
5
[*] Dr. R. Haiges, Dr. S. Schneider, Dr. T. Schroer, Prof. Dr. K. O. Christe
Loker Research Institute
Figure 1. Low-temperature Raman spectrum of N HF ·nHF. The bands
5
2
University of Southern California
Los Angeles, CA 90089-1661 (USA)
Fax: (+1)213-740-6679
marked by an asterisk (*) are due to the Teflon–FEP sample tube.
ꢀ
Bands marked by ^ arise from a trace of [SbF6] from the starting
+
material. The intense, unlabeled bands are from N5
.
E-mail: haiges@usc.edu
kchriste@usc.edu
[
**] This work was funded by the Defense Advanced Research Projects
Agency, the Air Force Office of Scientific Research and the National
Science Foundation. R.H. thanks the Deutsche Forschungsge-
meinschaft for a postdoctoral fellowship. We thank Prof. G. A. Olah,
and Drs. A. Morrish, D. Woodbury, and M. Berman, for their steady
support, and Dr. R. Wagner for his help and stimulating discus-
sions.
This reaction resulted in the formation of thermally
[25]
unstable, liquid NF HF ·nHF, which exhibited character-
4
2
+
istics very similar to those observed in the above N5 reaction,
that is, a failure to observe anion bands because a polybi-
fluoride anion is an extremely weak Raman scatterer. The
additional formation of N HF ·nHF in the reaction in
5
2
Angew. Chem. Int. Ed. 2004, 43, 4919 –4924
DOI: 10.1002/anie.200454242
ꢀ 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
4919

Communications
Equation (4) can be explained if liquid HF is capable of
ꢀ
displacing HN(CF ) from its [N(CF ) ] salts according to
3
2
3 2
Equation (6).
þ
ꢀ
þ
ꢀ
2
Cs ½NðCF Þ Š þ 2 HF ! Cs ½HF Š þ HNðCF3Þ2
ð6Þ
3
2
The above assumptions were confirmed by carrying out a
reaction of N SbF with CsF in anhydrous HF at ꢀ648C which
5
6
resulted in the expected precipitation of CsSbF and the
6
+
formation of a polybifluoride of N5 [Eq. (7)].
N SbF6 þ ½CsHF2Šꢀ þ n HFƒƒƒ!½N HF Š ꢁ n HF þ CsSbF # ð7Þ
HF
ꢀ
5
o
5
2
6
ꢀ
64 C
N HF ·nHF was isolated as a clear, colorless liquid after
5
2
filtering off the CsSbF precipitate and removing all volatiles
6
at ꢀ648C from the filtrate. The observed low-temperature
Raman spectrum was identical to that shown in Figure 1. It
exhibits, in addition to some weak bands due to the Teflon-
ꢀ
FEP sample container and a trace of [SbF ] from the starting
6
+
material, only bands due to N . The experimental Raman
5
frequencies and assignments are listed in Table 1. On warm-
ing to room temperature, the N HF ·nHF salt decomposed
5
2
under formation of trans-N F , NF , and N , which were
2
2
3
2
identified by checking for noncondensible gas at ꢀ1968C and
Figure 2. IR (upper trace) and Raman (lower trace) spectra of N PF .
5 6
The bands marked by an asterisk (*) are due to the Teflon–FEP sample
tube.
FT-IR spectroscopy.
The usefulness of the N HF ·nHF salt as a reagent for the
5
2
+
synthesis of other N5 salts by displacement reactions with
Lewis acids stronger than HF was explored by treating it with
[
26,27]
PF , BF , and HSO F,
resulting in the formation of N PF ,
5 6
5
3
3
N BF , and N SO F, respectively, according to Equations (8)–
5
4
5
3
(
10).
HF
N HF2 ꢁ n HF þ PF ƒƒƒ!N PF þ ðn þ 1Þ HF
ð8Þ
ð9Þ
5
5
o
5
6
ꢀ
64
C
HF
N HF2 ꢁ n HF þ BF ƒƒƒ!N BF þ ðn þ 1Þ HF
5
3
o
5
4
ꢀ
64 C
HF
o
N HF2 ꢁ n HF þ HSO Fƒƒƒ!N SO F þ ðn þ 2Þ HF
ð10Þ
5
3
5
3
ꢀ
64 C
All these new salts are white, marginally stable solids that
were characterized by NMR and vibrational spectroscopy.
1
4
Figure 3. Low-temperature Raman spectrum of N BF . The bands
The N NMR spectrum of N PF was recorded in HF at
5
4
5
6
marked by an asterisk (*) are due to the Teflon–FEP sample tube.
ꢀ
408C. It showed a strong resonance at d = ꢀ165.1 ppm for
ꢀ
Bands marked by ^ arise from a trace of [SbF6] from the starting
the N atoms and a very broad line at about d = ꢀ101 ppm for
b
material.
the terminal Na atoms, and is in good agreement with
+
[1–3]
previously published values for N5 salts.
In the
1
4
N NMR spectra of N BF and N SO F in HF at ꢀ408C,
5
4
5
3
the resonances for the Nb atoms were observed at d =
ꢀ
164.3 ppm and d = ꢀ164.7 ppm, respectively. The experi-
mental vibrational frequencies and assignments of the three
salts and, for comparison, of N SbF are listed in Table 1. The
5
6
observed Raman and IR spectra of N PF6 are shown in
5
Figure 2, and the Raman spectra of N BF and N SO F are
5
4
5
3
shown in Figure 3 and Figure 4, respectively. They establish
[
1–3,28–30]
beyond any doubt the composition of these salts
and
their ionic nature.
Whereas the N5 ion is a highly energetic ion with a
calculated endothermicity of 351.6 kcalmol ,
+
ꢀ1 [22]
all of its
Figure 4. Low-temperature Raman spectrum of N SO F. The bands
5
3
[
1–3]
known salts contained non-energetic counterions.
marked by an asterisk (*) are due to the Teflon–FEP sample tube.
Bands marked by ^ arise from a trace of [SbF6] from the starting
material.
ꢀ
Although a significant advance in potential performance
was achieved by successfully doubling the number of poly-
4
920
ꢀ 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
Angew. Chem. Int. Ed. 2004, 43, 4919 –4924

Angewandte
Chemie
Table 1: Observed vibrational frequencies of N HF ·nHF, N SbF , N PF , N BF , and N SO F and their assignments
5
2
5
6
5
6
5
4
5
3
ꢀ1
Observed frequency (cm ) and relative intensity
Assignments
[
2]
+
ꢀ
ꢀ
ꢀ
N HF ·nHF
N SbF6
N PF6
5
N BF
5
N SO F
N5 (C )
MF6 (Oh) [BF4]
[SO F]
5
2
5
4
5
3
2v
3
Raman
IR
Raman
IR
Raman
Raman
Raman
(Td)
(Td)
3
3
3
2
357 vw
3364 w
3337 w
3082 mw
2685 w
(n + n + n )(B )=3358
(n + n )(B )=3323
1 8 2
(n + n )(B )=3077
2 7 2
1
3
9
2
334 vw
079 vw
681 vw
(n + n )(B )=2682
1
9
2
2
279 (10)
218 (2.2)
2270 m
2268
2273 ms
2269
(10)
2209
(1.3)
2283
(10)
2221
(3.0)
2271 (10)
n (A )
1
1
(
9.4)
2205
2.0)
2
2205 s
2219 s
2210 (2.2) n (B )
7 2
(
1
1
921 vw
891 vw
1926 w
1891 w
(n + 3n )(B )=1914
3 9 2
(n +2n )(B )=1883
8
9
2
1
303 (1.7)
084 (5.3)
n4(E)
1
1
240 vw
092 ms
comb.
bands
[
a]
1099 s
1072 s
(n + n )(B )=1086
3
9
2
1
n (A )
1
1
1
9
064 s
n (B )
8
2
02 vvw
(n + n )(B )=903
5
6
2
8
77 (1.3)
40 (0.9)
871 w
872
0.6)
837
0+)
869
(0.6)
826
880
(1.5)
837
871 (2.3)
829 (1.7)
n (A )
2
1
(
[
b]
8
835 vw
(2n )(A )=828
9
1
(
(0+)
(0.7)
785 (2.1)
n (A )
2 1
771
n (A )
1 1
(2.9)
6
72 (2.7)
672 (1)
672 s
668
674
669 (3.2)
n (A )
3
1
(2.2)
(2.7)
ꢀ
655 vs
582 w
447 w
881 s,
n (F )
3
1u
8
39 vs
6
52 (10) 750 m
747
3.8)
n (A )
1 1g
(
ꢀ
5
5
74 (2.4),
64 (2.4)
n (A )
3 1
571
563 vs
578
(0.3)
n (E )
2 g
(0.8)
5
25
n (F )
4 2
(0.7)
4
81 (0.7)
478
0+)
473 w
447 w
476
(0.7)
477 (1.4)
n (A )
5 2
(
?
4
22 (0.6)
13 (0.6)
425 ms
426
420 (1.9)
407 (2.0)
n (B )
6 1
(0.4)
4
412 mw
416
0+)
416
(0+)
412
(0.5)
n (B )
9 2
(
284 vs
563 vs
473 w
n (F )
4 1u
n (F )
5 2g
2
82
474
(2.8)
(0.6)
350
n2(E)
(0.6)
2
02 (5.8)
204
5.0)
07
5.0)
211
(2.5)
120
202
(4.8)
113
203 (5.7)
111 (4.5)
n (A )
4 1
(
1
(
lattice vibrations
(1.6)
(2.0)
[
a] In Fermi resonance with n (B ). [b] In Fermi resonance with n (A ).
8
2
2
1
+
ꢀ
nitrogen ions in
a
salt by formation of
a
2:1 salt
after inclusion of entropy corrections, N5 N3 is unstable by
+
2ꢀ [3]
6
ꢀ1
[
N ] [SnF ] , salts containing energetic counterions were
76 kcalmol with respect to spontaneous decomposition to
In spite of these challenges, we have now
successfully synthesized two highly energetic N5 salts.
5
2
+
[22]
still missing. Attempts to combine the N ion with the
energetic anions, [ClO ] , [NO ] and N3 by metathetical
N3 and N2.
5
ꢀ
ꢀ
ꢀ
+
4
3
reactions failed, and a recent theoretical analysis showed that,
Angew. Chem. Int. Ed. 2004, 43, 4919 –4924
www.angewandte.org
ꢀ 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
4921

Communications
The metathetical reaction between N SbF and NaP(N )
5
6
3
6
in SO proceeded with the expected precipitation of NaSbF
2
6
+
and the combination of the N ion with the energetic ion
5
ꢀ[30]
P(N3)6
to form N P(N ) [Eq. (11)].
5
3 6
SO2
N SbF6 þ NaPðN Þ ƒƒƒ!N PðN Þ þ NaSbF #
ð11Þ
5
3
6
o
5
3
6
6
ꢀ
64 C
However, the compound is extremely shock sensitive and
violently explodes upon the slightest provocation or warming
towards room temperature (see Figure 5). In addition to its
very high energy content, this salt is remarkable for its high
nitrogen content of 91.2 wt%.
Figure 6. Low-temperature Raman spectrum of N P(N ) . The bands
5
3 6
marked by an asterisk (*) are due to the Teflon–FEP sample tube. The
two bands marked with ^ arise from the SO solvent.
2
Figure 5. Single-ended 9-mm o.d. Teflon-FEP ampule, used for record-
ing the Raman spectrum, after explosion of less than 500 mg of
+
ꢀ
N5 [P(N ) ] .
3
6
Figure 7. Low-temperature Raman spectrum of N B(N ) . The bands
In a similar fashion, N B(N ) was prepared from N SbF
5
3 4
5
3
4
5
6
[
32]
marked by an asterisk (*) are due to the Teflon–FEP sample tube.
and NaB(N3)
4
[Eq. (12)].
ꢀ
Bands marked by ^ arise from a trace of [SbF6] from the starting
SO2
material.
N SbF6 þ NaBðN Þ ƒƒƒ!N BðN Þ þ NaSbF #
ð12Þ
5
3
4
o
5
3
4
6
ꢀ
64 C
Again, the salt is extremely shock-sensitive and explodes
covalent azides which render the handling and further
characterization of these compounds particularly difficult.
on warming towards room temperature. Its nitrogen content
of 95.7 wt% significantly exceeds even that of N P(N ) and
5
3 6
any other known, solid high-nitrogen compound. There are
only five other compounds whose nitrogen content exceeds
Experimental Section
+
ꢀ
+
ꢀ
3
9
0 wt%. These are: [NH ] N
(93.3%), [N H ] N
+
4
3
2
5
Caution! Azides and N compounds are highly endothermic and can
5
+
ꢀ
(
(
93.3%), [N H ] N ·N H (91.6%), 2H-tetrazolylpentazole
+
2
5
3
2
4
decompose explosively under various conditions! N compounds are
5
+
ꢀ
[33]
[
1–3]
90.6%), and Li [B(N ) ] (90.4%). Attempts to carry out
3
4
highly energetic oxidizers.
Contact with potential fuels must be
the above metathetical reactions with CsP(N ) and CsB(N )
3 4
avoided. These materials should be handled only on a scale of less than
2 mmol. The polyazides in this work are extremely shock-sensitive.
Because of the high energy content and high detonation velocities of
these azides, their explosions are particularly violent and can cause,
even on a one mmol scale, significant damage. The use of appropriate
safety precautions, such as face shields, heavy leather welding suits,
3
6
in HF solution were unsuccessful because HF reacts with the
ꢀ
ꢀ
polyazido anions to give [PF6] and [BF ] , and lead to the
4
isolation of N PF and N BF , respectively. Both polyazido
5
6
5
4
salts were identified and characterized by low-temperature
Raman spectroscopy.
[34]
leather gloves, and ear plugs is mandatory. Teflon containers should
The experimental vibrational frequencies and tentative
assignments for N P(N ) and N B(N ) are given in the
be used, whenever possible, to avoid hazardous fragmentation.
Ignoring safety precautions can lead to serious injuries!
5
3
6
5
3 4
All reactions were carried out in Teflon-FEP (FEP = perfluoro-
ethylenepropylene polymer) ampules that were closed by stainless
steel valves. Volatile materials were handled in stainless steel/Teflon-
Experimental Section. The observed Raman spectra of
N P(N ) and N B(N ) are shown in Figure 6 and Figure 7,
5
3
6
5
3 4
respectively. In addition to high energy densities of about
[35]
FEP or grease-free Pyrex-glass vacuum lines. Nonvolatile solids
ꢀ
1
2
kcalgram and extremely high sensitivities, these com-
were handled in the dry argon atmosphere of a glove box. All reaction
pounds exhibit the typical high detonation velocities of
vessels and the stainless steel line were passivated with ClF prior to
3
use.
4
922
ꢀ 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
Angew. Chem. Int. Ed. 2004, 43, 4919 –4924

Angewandte
Chemie
ꢀ
1
ꢀ
+
+
ꢀ
4
Infrared spectra were recorded in the range 4000–400 cm on a
(B(N3)4 ), 483(2.3) (N n5), 421(2.1) (N5 n ), 293(2.4) (B(N ) ),
5 9 3
+
ꢀ1
ꢀ
4
Midac FT-IR model 1720 at a resolution of 1 cm . Spectra of solids
were obtained by using dry powders pressed between AgCl windows
in an Econo press (Barnes Engineering Co.). Raman spectra were
recorded in the range 4000–80 cm on a Bruker Equinox 55 FT-RA
spectrophotometer using a Nd:YAG laser at 1064 nm with power
levels of 200 mW or less. Pyrex melting point tubes that were baked
out at 3008C for 48 h at 10 mTorr vacuum or 9-mm o.d. Teflon-FEP
203(2.6) (N
n ), 189(5.0)/165(6.8)/123(10.0) (B(N ) ).
5 4 3
Received: March 11, 2004 [Z54242]
ꢀ1
Keywords: azides · high energy-density materials (HEDM) ·
nitrogen · polynitrogen chemistry · vibrational spectroscopy
.
tubes with stainless steel valves that were passivated with ClF were
3
1
4
used as sample containers. N NMR spectra were recorded unlocked
at 36.13 MHz on a Bruker AMX 500 spectrometer using solutions of
the compounds in DMSO in sealed standard glass tubes. Neat
[
1] K. O. Christe, W. W. Wilson, J. A. Sheehy, J. A. Boatz, Angew.
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Christe, J. Am. Chem. Soc. 2001, 123, 6308.
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Eur. J. 2003, 9, 2840.
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123, 3308.
[5] M. T. Nguyen, T. K. Ha, Chem. Phys. Lett. 2001, 335, 311.
[6] S. Fau, R. J. Bartlett, J. Phys. Chem. A. 2001, 105, 4096.
[7] R. J. Bartlett, Chem. Ind. 2000, 140, and references therein; a
compilation of data for N to N10 can be found at http://
www.qtp.ufl.edu/ ~ bartlett/downloads/polynitrogen.pdf.
8] G. Chung, M. W. Schmidt, M. S. Gordon, J. Phys. Chem. A 2000,
04, 5647, and references therein.
9] M. N. Glukhovtsev, H. Jiao, P. von R. Schleyer, Inorg. Chem.
996, 35, 7124, and references therein.
10] H. H. Michels, J. A. Montgomery Jr. , K. O. Christe, D. A.
Dixon, J. Phys. Chem. 1995, 99, 187.
[
CH NO (0.00 ppm) was used as the external reference.
3
2
The N FSbF starting material was prepared from cis-N F and
2
6
2
2
[
19,20,36–39]
SbF in anhydrous HF solution.
N SbF was prepared from
5 6
N FSbF and HN in HF, NaP(N ) was prepared from PCl and
5
[
2]
2
6
3
3
6
5
[
31]
[32]
NaN3, and NaB(N ) from NaBH and HN . The HF (Matheson
3
4
4
3
[
40]
Co.) was dried by storage over BiF5 (Ozark Mahoning).
PCl5
(
Aldrich) was purified by sublimation in a dynamic vacuum. The
CsF (KBI) was fused in a platinum crucible, transferred while hot to
the dry box, and finely powdered. BF3 (Matheson), PF5 (Ozark
Mahoning), NaN (Aldrich), NaBH (Aldrich), and HSO F (Aldrich)
were used without further purification.
N HF ·nHF: A solution of CsF (1.00 mmol) in HF (2 mL) was
2
3
4
3
[
1
5
2
[
siphoned through a Teflon–FEP tube into a Teflon–FEP ampule
1
containing a solution of N SbF (1.00 mmol) in HF (3 mL) at ꢀ648C.
5
6
[
Immediately, a white precipitate was formed. The reaction mixture
was stirred for 10 min to ensure complete reaction. The mixture was
allowed to settle, and the supernatant liquid was siphoned into a
[
[
11] G. Schatte, H. Willner, Z. Naturforsch. B 1991, 46, 483.
12] G. Rasul, G. K. S. Prakash, G. A. Olah, J. Am. Chem. Soc. 1994,
second Teflon–FEP ampule kept at ꢀ648C. The CsSbF residue was
6
1
16, 8985.
washed twice with HF (about 1 mL each time). The HF was pumped
off from the combined liquids at ꢀ648C, leaving behind a colorless
liquid (0.156 g; weight calculated for 1.00 mmol of N HF ·2.5HF:
[
[
13] W. E. Thompson, M. E. Jacox, J. Chem. Phys. 1990, 93, 3856.
14] J. P. Zheng, J. Waluk, J. Spanget-Larsen, D. M. Blake, J. G.
Radziszewski, Chem. Phys. Lett. 2000, 328, 227.
15] T. Ruchti, T. Speck, J. P. Connelly, E. J. Bieske, H. Linnertz, J. P.
Maier, J. Chem. Phys. 1996, 105, 2591.
[16] F. Cacace, G. de Petris, A. Troiani, Science 2002, 295, 480.
17] M. I. Eremets, R. J. Hemley, H. Mao, E. Gregoryanz, Nature
2001, 411, 170.
5
2
0
.159 g).
N PF and N BF : Excess PF or BF (2.0 mmol) was condensed
[
5
6
5
4
5
3
at ꢀ1968C into an ampule containing a frozen solution of N HF ·nHF
5
2
(
1.00 mmol) in HF (1 mL). The temperature was raised to ꢀ648C and
[
the reaction mixture kept at this temperature for 1 h to ensure
complete reaction. All volatile material was pumped off at ꢀ648C,
leaving behind a white solid (N PF : 0.220 g, weight calculated for
[18] T. Curtius, Ber. Dtsch. Chem. Ges. 1890, 23, 3023.
[19] A. V. Pankratov, N. I. Savenkova, Russ. J. Inorg. Chem. 1968, 13,
1345.
5
6
1
.00 mmol of N PF : 0.215 g; N BF : 0.167 g; weight calculated for
5 6 5 4
1
.00 mmol of N BF : 0.157 g).
[20] K. O. Christe, R. D. Wilson, W. W. Wilson, R. Bau, S. Sukumar,
D. A. Dixon, J. Am. Chem. Soc. 1991, 113, 3795.
[21] K. O. Christe, D. A. Dixon, D. McLemore, W. W. Wilson, J. A.
Sheehy, J. A. Boatz, J. Fluorine Chem. 2000, 101, 151.
5
4
N SO F: At ꢀ648C, a solution of HSO F (1.00 mmol) in HF
5
3
3
(
(
2 mL) was added to a solution of N HF ·nHF (1.00 mmol) in HF
5 2
1 mL). The reaction mixture was stirred for 30 min at this temper-
[
22] D. A. Dixon, D. Feller, K. O. Christe, W. W. Wilson, A. Vij, V.
Vij, H. D. B. Jenkins, R. M. Olsen, M. S. Gordon, J. Am. Chem.
Soc. 2004, 126, 834.
ature to ensure complete reaction. All volatiles were pumped off at
648C leaving behind a white solid (0.175 g; weight calculated for
.00 mmol of N SO F: 0.169 g).
ꢀ
1
5
3
[
[
[
23] H. M. Netzloff, M. S. Gordon, K. O. Christe, W. W. Wilson, A.
Vij, V. Vij, J. A. Boatz, J. Phys. Chem. A 2003, 107, 6638.
24] A. Hammerl, T. M. Klapoetke, P. Schwerdtfeger, Chem. Eur. J.
N P(N ) and N B(N ) : At ꢀ648C, a solution of N SbF
5
3
6
5
3
4
5
6
(0.50 mmol) in SO (3 mL) was added to a solution of NaB(N ) or
2
3
4
NaP(N ) (0.50 mmol) in SO (3 mL), respectively. After the mixture
had settled, the liquid phase was transferred into another Teflon–FEP
3
6
2
2
003, 9, 5511.
25] K. O. Christe, W. W. Wilson, R. D. Wilson, Inorg. Chem. 1980,
9, 1494.
ampule that had been cooled to ꢀ648C, and the remaining NaSbF
6
1
was washed twice with about SO (1 mL). Pumping on the collected
2
[26] W. W. Wilson, K. O. Christe, J. Fluorine Chem. 1982, 19, 253.
[27] W. W. Wilson, K. O. Christe, Inorg. Chem. 1982, 21, 2091.
[28] K. O. Christe, C. J. Schack, R. D. Wilson, Inorg. Chem. 1976, 15,
liquid phase at ꢀ648C gave a white solid. N P(N ) : 0.184 g, expected
5
3 6
+
for 0.50 mmol: 0.177 g; Raman (50 mW, ꢀ808C): n˜ = 2266(10.0) (N
5
+
ꢀ
n ), 2203(7.5) (N n ), 2182(5.4)/2074(2.9) (P(N ) n N ), 1302(4.7)
1
5
7
3
6
as
3
1275.
ꢀ
+
ꢀ
6
(
(
4
P(N ) n N ), 873(3.9) (N n ), 730(7.4) (P(N ) nPN), 666(8.0)
N5 n ), 522(5.0) ((P(N ) dN ), 483(4.6) (N5 n5), 419(4.7) (N n ),
3
6
s
3
5
2
3
[29] K. O. Christe, R. D. Wilson, C. J. Schack, Inorg. Chem. 1980, 19,
3046.
+
ꢀ
+
+
5
3
3
6
3
9
ꢀ
ꢀ
+
58(4.7) ((P(N3)
6
dPNN), 327(4.9) ((P(N3)
6
dPNN), 203(9.1) (N5
[30] H. Siebert, Anwendungen der Schwingungsspektroskopie in der
Anorganischen Chemie, Anorganische und Allgemeine Chemie
in Einzeldarstellungen, VII, Springer, Heidelberg, 1996.
[31] a) H. W. Roesky, Angew. Chem. 1967, 79, 651; Angew. Chem. Int.
Ed. Engl. 1967, 6, 637; b) P. Volgnandt, A. Schmidt, Z. Anorg.
Allg. Chem. 1976, 425, 189.
n )
4
N B(N ) : 0.137 g; expected for 0.50 mmol: 0.124 g; Raman
5
3 4
+
+
(
2
50 mW, ꢀ808C): n˜ = 2269(1.9) (N5 n1), 2207(1.2) (N5 n ),
7
ꢀ
ꢀ
172(5.4)/2148(2.0) (B(N )
n N ), 1334(2.9)/1292(3.7) (B(N )
as 3 3 4
+
3
4
+
n N ), 875(3.1) (N5 n2), 664(3.6) (N5 n3), 581(3.0)/532(4.7)
s
3
Angew. Chem. Int. Ed. 2004, 43, 4919 –4924
www.angewandte.org
ꢀ 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
4923

Communications
[
32] a) E. Wiberg, H. Michaud, Z. Naturforsch. 1954, 96, 497; b) W.
Freank, T. Habereder, A. Hammerl, T. M. Klapꢀtke, B. Krumm,
P. Mayer, H. Nꢀth, M. Warchhold, Inorg. Chem. 2001, 40, 1334;
c) W. Fraenk, H. Nꢀth, T. M. Klapꢀtke, M. Suter, Z. Naturforsch.
B 2002, 57, 621.
[
[
33] A. Hammerl, T. M. Klapoetke, Inorg. Chem. 2002, 41, 906, and
references therein.
34] a) R. Haiges, A. Vij, J. A. Boatz, S. Schneider, T. Schroer, M.
Gerken, K. O. Christe, Chem. Eur. J. 2004, 10, 508; b) R. Haiges,
J. A. Boatz, A. Vij, M. Gerken, S. Schneider, T. Schroer, K. O.
Christe, Angew. Chem. 2003, 115, 6027; Angew. Chem. Int. Ed.
2003, 42, 5847; c) R. Haiges, J. A. Boatz, S. Schneider, T. Schroer,
M. Yousufuddin, K. O. Christe, Angew. Chem. 2004, 116, 3210;
Angew. Chem. Int. Ed. 2004, 43, 3148.
[
35] K. O. Christe, W. W. Wilson, C. J. Schack, R. D. Wilson, Inorg.
Synth. 1986, 24, 39.
[
[
[
36] D. Moy, A. R. Young, J. Am. Chem. Soc. 1965, 87, 1889.
37] J. K. Ruff, Inorg. Chem. 1966, 5, 1971.
38] H. W. Roesky, O. Glemser, D. Bormann, Chem. Ber. 1966, 99,
1
589.
39] K. O. Christe, R. D. Wilson, W. Sawodny, J. Mol. Struct. 1971, 8,
45.
40] K. O. Christe, W. W. Wilson, C. J. Schack, J. Fluorine Chem.
978, 11, 71.
[
[
2
1
4
924
ꢀ 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
Angew. Chem. Int. Ed. 2004, 43, 4919 –4924