The reaction of dioxygenyl salts with 13CO Formation of F13C(O)13C(O)F

Article abstract of DOI:10.1016/S0022-1139(01)00512-7

Oxalyl fluoride has been prepared directly in high yield from CO and the dioxygenyl salts O₂[BF₄] or O₂[AsF₆]. The formation of intermediate FCO radicals is indicated by differences in reaction rates and the observation of FC(O)OOC(O)F as a by-product. From the analysis of the NMR spectra of ¹³C enriched FC(O)C(O)F including selective irradiation experiments positive signs for both the FF (+50.6 Hz) and CC (+126.1 Hz) coupling constants are deduced. From the temperature dependency of ³J(FF), values of +70 Hz and -10 Hz are estimated for the trans- and cis-rotamers, respectively.

Full text of DOI:10.1016/S0022-1139(01)00512-7

Journal of Fluorine Chemistry 112 12001) 277±281
13
The reaction of dioxygenyl salts with CO
Formation of F13CꢀO†13CꢀO†F
Holger Pernicea, Helge Willnera,*, Reint Eujenb,1
a
È
FB6, Anorganische Chemie, Gerhard-Mercator-Universitat Duisburg, Lotharstr. 1, D-47057 Duisburg, Germany
bFB9, Anorganische Chemie, Bergische UniversitaÈt Wuppertal, Gauûstr. 20, D-42097 Wuppertal, Germany
Received 31 May 2001; accepted 31 August 2001
Abstract
Oxalyl ¯uoride has been prepared directly in high yield from CO and the dioxygenyl salts O2[BF4] or O2[AsF6]. The formation of
intermediate FCO radicals is indicated by differences in reaction rates and the observation of FC1O)OOC1O)F as a by-product. From the
analysis of the NMR spectra of 13C enriched FC1O)C1O)F including selective irradiation experiments positive signs for both the FF
1‡50.6 Hz) and CC 1‡126.1 Hz) coupling constants are deduced. From the temperature dependency of 3J1FF), values of ‡70 Hz and
À10 Hz are estimated for the trans- and cis-rotamers, respectively. # 2001 Elsevier Science B.V. All rights reserved.
Keywords: Dioxygenyl cation; Isotopic labeling; NMR spectroscopy; Oxalyl ¯uoride; Radicals
1. Introduction
high-energy oxidizer and its chemistry has been exploited in
solid salts or in aHF solution. It oxidizes xenon [13] and
radon [14], and this property can be applied to remove
radioactive gases from nuclear power plants and nuclear
Since the discovery of the ®rst dioxygenyl salt O2[PtF6]
by Bartlett and Lohmann [1], many other dioxygenyl salts
containing the anions e.g. [MF6]À, M ˆ P [2], As, Sb, Bi,
Nb, Ta, Ru, Rh, Pd, Au [3,4], [M2F11]À, M ˆ Nb, Ta [3], Sb
[3,5], [MF6]2À, M ˆ Ni, Mn [6] and [BF4]À [2] have been
synthesized. They are conveniently prepared by photolysis
of O2/F2 mixtures together with the respective Lewis acid
[5,7] and characterized by vibrational spectroscopy [4±6,8],
X-ray powder diffraction [1,5] and ESR spectroscopy [7].
The O±O stretching wavenumber is strongly dependent on
the nature of the counter anion and spans from 1801 cmÀ1 in
the [O2]2[NiF6] [6] to 1866 cmÀ1 in O2Ni[AsF6]3 [8]. The
crystal structures of O2[MF6] salts with M ˆ Sb, Ru, Pt, Au
have been determined by single crystal X-ray diffraction [9].
But only recently a low temperature X-ray structure analysis
of a [O2][RuF6] single crystal [10] has proved the previously
‡
fuel reprocessing plants [15]. The O2 salts also have been
‡
used to prepare salts of C6F6 [16], to oxidize HSO3F to
S2O6F2 [17], isotopic enriched water to labeled ozonÀe,
ÃOO2, [18], and Ag1I), Ni1II), Au1III), Pt1IV) to [AgF4] ,
[NiF6]2À, [AuF6]À, [PtF6]À, respectively [19]. In the latter
case in situ generated O2F dissolved in aHF was used as a
‡
vehicle for O2 cations. O2F radicals are also involved in
the gas phase reaction system O2/F2/CO which yields
the peroxide FC1O)OOC1O)F [20]. This peroxide is an
excellent thermal source for the synthesis of the unusual
FCO2 radical [21]. The determination of its molecular
structure is at present under investigation [22]. In the
course of these studies we became interested in the
mechanism of the O2/F2/CO reaction system, checked
the reaction between carbon monoxide and dioxygenyl
salts, and discovered that oxalyl ¯uoride is formed in
high yield.
‡
conjectured three-fold disorder of the O2 cation in
[O2][PtF6] [11] and resulted in an interatomic O±O distance
Ê
of 1.125 117) A in agreement with the gas phase value of
Ê
1.1227 A [12]. The dioxygenyl cation is an one-electron
In general oxalyl ¯uoride is synthesized by ¯uorination
of oxalyl chloride [23,24], but this route is not suitable
for the preparation of isotopic enriched oxalyl ¯uoride.
Hence, the above-mentioned new route enabled us to
synthesize F13CꢀO†13CꢀO†F and to perform an extensive
NMR study on this text book example for a [AX]2 spin
system [25,26].
* Corresponding author. Fax: ‡49-203-379-2231.
E-mail addresses: willner@uni-duisburg.de 1H. Willner),
eujen@uni-wuppertal.de 1R. Eujen).
1 Co-corresponding author. Fax: ‡49-202-439-3052.
0022-1139/01/$ ± see front matter # 2001 Elsevier Science B.V. All rights reserved.
PII: S 0 0 2 2 - 1 1 3 9 1 0 1 ) 0 0 5 1 2 - 7

278
H. Pernice et al. / Journal of Fluorine Chemistry 112 82001) 277±281
2. Results and discussions
synthesis and characterization of this simple dication may
be a challenge for both experimentalists and theorists. Also
formation of the intermediate cation [OC±OO] can be ruled
‡
2.1. Synthesis
out, because after ¯uoride ion abstraction from the anion the
FC1O)OO radical [29] would be formed, which is the
precursor for the peroxide FC1O)OOC1O)F [20,30,31]. A
good indication for the reaction mechanism stems from the
reaction rate of the different dioxygenyl salts. The thermal
stability of the salts O2[SbF6], O2[AsF6], O2[BF4] decrease
in this order due to an increase of the interionic interaction
and preformation of the O2F radical. Therefore, ¯uorine
atom transfer to CO may occur on the surface of the
dioxygenyl salts, and subsequent dimerization of the FCO
radicals leads to FC1O)C1O)F. Side reactions of the FCO
radicals with O2 or the dioxygenyl salt give FC1O)OOC1O)F
or COF2 according to
Oxalyl ¯uoride has been prepared in high yields from
carbon monoxide and a dioxygenyl salt in an one-step
reaction according to
2O2‰BF4Š ‡ 2CO ! FCꢀO†CꢀO†F ‡ 2O2 ‡ 2BF3
2O2‰MF6Š ‡ 2CO ! FCꢀO†CꢀO†F ‡ 2O2 ‡ 2MF5
11)
ꢀM ˆ As; Sb† 12)
The reaction rates of the heterogeneous reactions between
the solid dioxygenyl salts and gaseous CO at ca. 200 mbar
and À608C are very different. Reaction 11) is completed
within 3±4 h, in the case of the [AsF6]À salt 12) about 6 h are
needed, and within 6 h only a few percent of the [SbF6]À salt
12) is converted. Because the equimolar by-product AsF5 is
much more difficult to separate from oxalyl fluoride than
BF3, most experiments have been performed with the
O2[BF4] salt. In all cases COF2 and FC1O)OOC1O)F have
been observed as side-products.
This new route to oxalyl ¯uoride is especially useful for
the synthesis of isotopic labeled species and is applied in this
study to the preparation of F13CꢀO†13CꢀO†F for a subse-
quent comprehensive NMR investigation 1vide infra). From
the analytical point of view, IR spectroscopy is the easiest
way to distinguish between natural and isotopic enriched
oxalyl ¯uoride as demonstrated in Fig. 1.
FCO ‡ O2 ! FCꢀO†OO
FCꢀO†OO ‡ FCO ! FCꢀO†OOCꢀO†F
FCO ‡ O2‰BF4Š ! COF2 ‡ O2 ‡ BF3
13)
14)
15)
If in the reaction vessel additional oxygen is introduced, the
formation of FC1O)OOC1O)F is increased and even the new
trioxide FC1O)OOOC1O)F is observed [32].
2.2. NMR spectra
The NMR spectra of 13C enriched FC1O)C1O)F represent
19
a text book example for an [AX]2 spin system with A ˆ
F
12
13
13
It is of interest to elucidate the mechanism of reaction 11)
‡
and X ˆ C. The presence of the isotopomers F CꢀO† -
CꢀO†F 115%, [ABX] spin system) and F12CꢀO†12CꢀO†F
11%, [A2]) in the investigated sample gives raise to additional
lines. Due to distinct 13C=12C isotope shifts 1Table 1) all
and 12). The oxidizing strength of the O2 cation 1IP ˆ
‡
12:070 eV [27]) is too low to oxidize CO to the CO cation
1IP ˆ 14:014 eV [28]), therefore formation of an intermedi-
ate like [CO][BF4] is not possible. Even formation of the
possible dication [OC±CO]2‡ 1isoelectronic to NC±CN)
seems to be thermodynamically unfavorable. However,
expected 19 110 ‡ 8 ‡ 1) lines are readily detected in the 19
F
Table 1
19F and 13C NMR data of FC1O)C1O)X 1X ˆ F, Cl)a
FC1O)C1O)F
FC1O)C1O)Cl
dꢀ19F†
1D19Fꢀ
2D19Fꢀ
1D19Fꢀ
dꢀ13C†
‡23.8
‡15.7
13=12
12=13
13=13
b,c
b,c
b
C†
C†
C†
À0.133
À0.016
À0.148
‡143.2
À0.129
À0.013
À0.132
‡145.0 1CF)
‡157.2 1CCl)d
1J1CF) 1dJ/dT)c
2J1CF) 1dJ/dT)c
1J1CC) 1dJ/dT)c
3J1FF) 1dJ/dT)c
À366.3 1À0.022)
‡102.8 10.018)
‡126.1 10.002)
‡50.6 1À0.068)
À376.2 1À0.020)
‡96.7 10.042)
‡112.9e
±
a In CD2Cl2 at 295 K. Chemical shifts in ppm refer to internal CFCl3
119F) and to CD2Cl2 at 53.7 ppm 113C). Coupling constants are in Hz; their
temperature coefficients given in parentheses are in Hz KÀ1
.
b Isotopic shifts D of the 19F resonance in ppm ꢀdꢀF13C† À dꢀF12C††;
Fig. 1. IR spectra of 3.8 mbar natural 1upper trace) and 13C enriched
oxalyl fluoride measured at 25 8C in a gas cell of 200 mm optical path
length. The isotopic shifts for the bands at 1850, 1250, 1100, 800 and
670 cmÀ1 are 42.7, 38.2, 24, 4.7 and 6.3 cmÀ1, respectively. Traces of BF3
and FC1O)OOC1O)F are indicated by 1*) and 1*), respectively.
for definition see [40].
3
c [33]: 1J1CF) Æ365.9 Hz, 2JꢀCF† Ç 103:2 Hz, j JꢀFF†j51:5 Hz,
1D19Fꢀ13=12C† À0.133 ppm, 2D19Fꢀ12=13C† À0.018 ppm.
d d113C) ClC1O)C1O)Cl 159.8 ppm.
e 1dJ/dT) was not determined.

H. Pernice et al. / Journal of Fluorine Chemistry 112 82001) 277±281
279
Fig. 3. 13C NMR spectrum of F13CꢀO†13CꢀO†F recorded at 62.90 MHz
1upper trace). The lower trace shows the effect of selective irradiation of
the lowest 19F transition of the [AX]2 system. Signals marked with closed
circles are due to F13CꢀO†12CꢀO†F.
symmetric part, containing the N lines and one AB sub
spectrum, and an antisymmetric part with the second AB
spectrum. Since one of the N lines is split 1Fig. 3), the
irradiated transition must belong to the symmetric part. If the
adjacent line which belongs to the other AB sub spectrum is
irradiated, the N lines are not affected. This implies that the
Fig. 2. Experimental 1up) and simulated 1down) 19F NMR spectrum of
F13CꢀO†13CꢀO†F recorded at 235.36 MHz. Signals marked with closed
circles are due to F13CꢀO†12CꢀO†F 115%), the signal with the open circle is
due to F12CꢀO†12CꢀO†F 11%).
3
NMR spectrum, which is displayed in Fig. 2 along with a
simulation. Isotope shifts are much smaller and not resolved
in the 13C NMR spectrum, and the two strongest lines of
the ABX system are hidden by the central N lines of
the dominating [AX]2 system, while the ``forbidden''
ABX lines are very weak, but clearly visible close to the
band center.
1J1CC) and J1FF) possess the same sign. A closer inspec-
tion of the spin system further reveals that the speci®c N line
is only concerned if both signs are positive, yielding
1
3JꢀFF† ˆ ‡51 Hz and JꢀCC† ˆ ‡126 Hz. The results of
the irradiation of the other 19F transitions are in full agree-
ment with the given assignment.
We have also studied the NMR spectra of the mixed
¯uoride chloride, FC1O)C1O)Cl. The relaxation times T1
of the 13C spins have been determined to be 31.5 and 41.5 s
The absolute values of the one-bond and two-bond 13C19F
couplings are directly accessible from the ABX system of
F13CꢀO†12CꢀO†F and are in good agreement with the values
reported by Bacon and Gillespie [33]. The opposite sign of
these couplings, that is an indisputable negative 1J1CF) and
positive 2J1CF) value, is con®rmed by the distance of the N
for 13C1F) and 13C1Cl), respectively. Observation of the 13
C
satellites of the two 13C resonances yields the one-bond
coupling 1J1CC). Its sign was determined by selective
irradiation of the 19F transitions of the corresponding
ABX spin system which is very close to ®rst order due to
the large difference of the 13C chemical shifts. The 4 X lines
formed by the 13C satellites of the 13C satellites of the 19F
resonance line, while very weak, are clearly visible if
recorded on neat or concentrated samples. Irradiation of
the lowest 19F frequency of the 13C13C isotopomer affects
the low-frequency satellites of the 13C resonances which is
1
lines of the [AX]2 spin system, j JꢀCF† ‡2 JꢀCF†j. Simi-
3
larly, the J1FF) coupling is evident from the ABX spin
system while 1J1CC) is obtained from the two AB sub
spectra of the [AX]2 system, the respective couplings being
1
1
3
K ˆ j JꢀCC† ‡3 JꢀFF†jand M ˆ j JꢀCC† À JꢀFF†j. Infor-
mation about absolute signs of these couplings becomes
available by selective irradiation experiments. Fig. 3 shows
the effect upon irradiation of the 19F transition which is
lowest in energy and which forms part of one of the AB sub
spectra of the 13C13C isotopomer. Those energy levels which
are connected by the irradiated transition are split, thus
those transitions which share one of these levels will also
be split. Furthermore, the population of the respective levels
is altered, e.g. saturation may lead to population inversion
and negative peaks for regressive 1Dm ˆ 0) but intensi®ca-
tion of progressive 1Dm ˆ 2) connections. In principal,
the energy levels of an [AX]2 spin system divide into a
1
in accord with a positive sign for J1CC).
Oxalyl ¯uoride exists as a mixture of two rotamers, a more
stable trans form and a less stable cis form [34]. Based on the
reported small enthalpy difference of 2:7 Æ 0:6 kJ molÀ1
along with the low rotational barrier of 10:9 Æ 2:0 kJ molÀ1
hen cooling down diluted solutions of FC1O)C1O)F or
FC1O)C1O)Cl in CD2Cl2 from 295 to 213 K or 195 K,
respectively, we could not observe a signi®cant broadening
of lines. Further cooling led to precipitation of the oxalyl
halides. Since the values of shifts and coupling constants are

280
H. Pernice et al. / Journal of Fluorine Chemistry 112 82001) 277±281
weighed averages of the respective values of the trans and
cis isomers, there should be a slight but signi®cant tem-
perature dependence of those values which differ strongly.
Inspection of the 19F chemical shifts yields temperature
coef®cients of ‡0.001 ppm KÀ1 and ‡0.016 ppm KÀ1 for
the di¯uoride and mixed halide, respectively. Similarly, the
temperature dependence of the coupling constants 1Table 1)
us to observe the reaction products and the puri®cation
processes immediately.
Air and moisture sensitive solids were manipulated inside
an inert atmosphere box 1Braun, MuÈnchen, Germany)
¯ushed with argon, with a residual moisture content of less
than 1 ppm. NMR measurements were carried out with
samples, ¯ame sealed in 5 mm o.d. tubes, with CD2Cl2
1Merck) as internal lock and a few % of CFCl3 as reference.
The following gases were obtained from commercial
sources and used after low temperature distillation: O2
1Linde), F2 1Solvay), CO 1Linde), 13CO 1Deutero), BF3
1Baker), AsF5 1Baker). Liquid SbF5 1Ozark-Mahoning)
was used as received. FC1O)C1O)Cl was prepared according
to a literature procedure [24] and stored in ¯ame-sealed glass
ampoules under liquid nitrogen in a long-term Dewar vessel.
By using the ``ampoule key'' [38] the ampoules were opened
on the vacuum line, an appropriate amount was taken out for
the experiments and then they were ¯ame-sealed again.
3
albeit small is by far the largest for J1FF). A low depen-
dence is expected for the ``®xed'' couplings 1J1CF), 2J1CF)
and 1J1CC). In contrast, 3J1FF) should be quite sensitive to
the torsional angle. Inspection of literature data [36] reveals
large differences for cis and trans couplings quite often
connected with a change of the sign. For example, in
¯uorinated ethylenes the cis coupling is usually positive
while the trans coupling adopts a large negative value, e.g.
3
3J1FFcis) ‡73 Hz and J1FFtrans) À111 Hz for tetra¯uor-
oethylene. On the other hand, a positive sign has been
reported for 3J1FFtrans) in CF3CFCl2 while the gauche
coupling is negative. Similarly, positive trans and negative
cis 3J1FF) couplings have been observed in ¯uorinated
cyclobutanes. Assuming that the intrinsic temperature
dependence of the FF couplings of the isolated rotamers
is negligible, a rough estimate of the trans and cis couplings
in FC1O)C1O)F can be given. Based on the enthalpy differ-
ence of 2.7 kJ molÀ1, the amount of the trans isomer will
increase from 75% at 295 K to 82% at 213 K which leads
to an estimated ‡70 Hz for the trans and À10 Hz for the
cis coupling.
3.2. Synthetic reactions
The dioxygenyl salts were prepared by a modi®ed litera-
ture procedure [5,7]. At the vacuum line an evacuated
250 ml glass bulb, ®tted with a 10 mm valve having a PTFE
stem 1Young, London), was ®lled with 2.80 mmol BF3,
2.40 mmol F2, and 3.20 mmol O2. The bulb was placed in
a Dewar vessel containing a cold dry ice ethanol bath. The
cold gas mixture was irradiated from top with UV-light of a
1000 W mercury high pressure lamp 1type CS 1000W 2,
Philips) for 1 h, and a white deposit was formed. The excess
of O2 and F2 was pumped off at À196 8C, and after warming
to À78 8C no volatile material could be detected. The mass
of the bulb increased by 320 mg of O2[BF4] 196% yield).
O2[BF4] is thermally unstable and it was used directly for the
further reaction with CO. In a similar way O2[AsF6] was
prepared in nearly quantitative yield, and the solid product
was stored in the dry box. The synthesis of O2[SbF6] was
performed according to the literature procedure [5].
The synthesis of the isotopic labeled F13CꢀO†13CꢀO†F
was accomplished by the thermal reaction of O2[BF4] with
13CO. Into the above-mentioned evacuated bulb containing
320 mg O2[BF4] 12.69 mmol) a small amount of 1.63 mmol
13CO 11.63 mmol) was introduced at À196 8C. The remain-
ing 13CO in the vacuum line was recovered by cryopumping
of the carbon monoxide into a vessel ®lled with molecular
3. Experimental section
Caution: Fluorine, BF3, AsF5, and SbF5 are very toxic
and aggressive chemicals and they can cause severe burns.
The experimentalist must become familiar with the safe
handling of these reagents, before undertaking work as
described here. Fresh tubes of calcium gluconate gel as
well as cortisone ointment and spray should always be on
hand for the fast treatment [37] of skin and respiratory tract
exposed to these reagents.
3.1. General procedures and reagents
Fluorine was measured by PVT and handled in a stainless
steel vacuum line equipped with a capacitance pressure
gauge 1Model 205±2, 0±1700 mbar, Setra Acton, MA).
Other volatile materials were manipulated in a glass vacuum
line equipped with two capacitance pressure gauges 1221
AHS-1000 and 221 AHS-10, MKS Baratron, Burlington,
MA), three U-traps, and valves with PTFE stems 1Young,
London, UK). The vacuum line was connected to an IR cell
1optical path length 200 mm, Si windows 0.5 mm thick)
contained in the sample compartment of the FTIR instru-
ment 1Nicolet, Impact 400 D, Madison, WI). Gas-phase
infrared spectra were recorded with a resolution of
2 cmÀ1 in the range of 4000±400 cmÀ1. This set-up allowed
Ê
sieve 15 A) held at À196 8C. Subsequently the reaction
vessel was kept at À60 8C for 3.5 h. After cooling to
À196 8C, formation of a non-condensable IR inactive gas
1oxygen) and consumption of all 13CO was recognized. By
warming the bulb slowly to ca. 0 8C, all volatile products
were evaporated and passed in vacuo through traps held at
À120 and À196 8C, respectively. The trap held at À120 8C
retained most of the F13CꢀO†13CꢀO†F contaminated with
some F13CꢀO†OO13CꢀO†F, and at À196 8C some 13COF2
and BF3 were trapped. By repeated fractional sublimation
the product was puri®ed and 44 mg of pure F13CꢀO†13CꢀO†F

H. Pernice et al. / Journal of Fluorine Chemistry 112 82001) 277±281
281
[4] J.E. Griffiths, W.A. Sunder, W.E. Falconer, Spectrochim. Acta, Part
A 31 11975) 1207.
10.46 mmol, 56% yield) was isolated. With two more
batches ®nally a total amount of 130 mg was prepared.
The reactions between CO and O2[AsF6] under the same
conditions as described above was slower and needed about
6 h for completion. In the same time only a few percent of
O2[SbF6] was reacted.
[5] D.E. McKee, N. Bartlett, Inorg. Chem. 12 11973) 2738.
[6] R.A. Bougon, K.O. Christe, W.W. Wilson, J. Fluorine Chem. 30
11985) 237.
[7] J. Shamir, J. Binenboym, Inorg. Chim. Acta 2 11968) 37.
[8] Z. Mazej, P. Benkic, K. Lutar, in: Proceedings of the 17th
International Symposium on Fluorine Chemistry, Durham, 16±21
July 2000, 2±P99.
3.3. NMR spectroscopy
[9] O. Graudejus, B.G. MuÈller, Z. Anorg. Allg. Chem. 622 11996) 1076.
[10] P. Botkovitz, G.M. Lucier, R.P. Rao, N. Bartlett, Acta Chim. Slov. 46
11999) 141.
Temperature dependent NMR spectra were obtained on
a Bruker AC250 spectrometer operating at 62.90 or
235.36 MHz for 13C or 19F nuclei, respectively. Isotopic
shifts were con®rmed using a Bruker ARX400 spectro-
meter. The NMR signals were referenced using CD2Cl2
at 53.7 ppm and CFCl3 as internal standards. Selective
c.w. or pulsed 19F irradiation was achieved using a
second synthesizer connected to a power ampli®er 1Bruker
BSV3BX).
The investigated NMR sample contained 100 mg
F13CꢀO†13CꢀO†F dissolved in 600 mg CD2Cl2 with
2 mol% CFCl3 as internal 19F standard. Due to the thermal
properties of FC1O)C1O)F [39], it crystallized at À30 8C
from this solution. For studies at lower temperatures a
sample containing ca. 5 mol% F13CꢀO†13CꢀO†F in CD2Cl2
was used. The 13C data for FC1O)C1O)Cl were collected
using an almost neat sample containing a small amount of
the dichloride while temperature dependencies and chemical
shifts were taken on a sample of ca. 5 mol% FC1O)C1O)Cl
and 1 mol% CFCl3 in CD2Cl2.
[11] J.A. Ibers, W.C. Hamilton, J. Chem. Phys. 44 11966) 1748.
[12] G. Herzberg, Molecular Spectra and Molecular Structure, I. Spectra
of Diatomic Molecules, Van Nostrand, Princeton, NJ, 1950.
[13] L. Stein, Science 175 11972) 1463.
[14] F.A. Hohorst, L. Stein, E. Gebert, Inorg. Chem. 14 11975) 2233.
[15] L. Stein, US Patent 3,829,551 11974).
[16] T.J. Richardson, F.L. Tanzella, N. Bartlett, J. Am. Chem. Soc. 108
11986) 4937.
[17] A. Smalc, Vestn. Slov. Kem. Drus. 21 11974) 5.
[18] A. Dimitrov, K. Seppelt, D. Scheffler, H. Willner, J. Am. Chem. Soc.
120 11998) 8711.
[19] G.M. Lucier, C. Shen, S.H. Elder, N. Bartlett, Inorg. Chem. 37 11998)
3829.
[20] A.J. Arvia, P.J. Aymonino, H.J. Schumacher, Z. Anorg. Allg. Chem.
316 11962) 327.
[21] G.A. ArguÈello, H. Grothe, M. Kronberg, H. Willner, H.-G. Mack, J.
Phys. Chem. 99 11995) 17525.
[22] M. Bogey, P. Drean, Z. Zelinger, J. Breidung, W. Thiel, H. BuÈrger, S.
von Ahsen, H. Pernice, H. Willner, in preparation.
[23] C.W. Tullock, D.D. Coffmann, J. Org. Chem. 25 11960) 2016.
[24] R. Franz, J. Fluorine Chem. 15 11980) 423.
[25] H.M. McConnell, A.D. McLean, C.A. Reilly, J. Chem. Phys. 23
11955) 1152.
[26] H. GuÈnther, Angew. Chem. 84 11972) 907.
[27] R.G. Tonkyn, J.W. Winniczek, M.G. White, Chem. Phys. Lett. 164
11989) 137.
Acknowledgements
[28] P. Erman, A. Karawajczyk, E. Rachlew-Kallne, C. Stromholm, J.
Larsson, A. Persson, R. Zerne, Chem. Phys. Lett. 215 11993) 173.
[29] S. Sander, H. Pernice, H. Willner, Chem. Eur. J. 6 12000) 3645.
[30] T.J. Wallington, M.D. Hurley, M.M. Maricq, Chem. Phys. Lett. 205
11993) 62.
Financial support by the Deutsche Forschungsge-
meinschaft, DFG, the Fonds der Chemischen Industrie
and the DAAD 1German Argentinien exchange program
PROALAR) is acknowledged. Furthermore, we are grateful
to Solvay, Hannover and MAN, MuÈnchenÐin particular
Dr. E. JacobÐfor the donation of ¯uorine and laboratory
equipment, respectively.
[31] G. Bednarek, G.A. ArguÈello, R. Zellner, Ber. Bunsen-Ges. Phys.
Chem. 100 11996) 445.
[32] H. Pernice, H. Willner, M.L. McKee, T.R. Webb, unpublished results.
[33] J. Bacon, R.J. Gillespie, J. Chem. Phys. 38 11963) 781.
È È
[34] S. Sander, H. Willner, L. Khriachtchev, M. Pettersson, M. Rasanen,
E.L. Varetti, J. Mol. Spectrosc. 203 12000) 145.
[35] K.-M. Marstokk, H. Mollendal, Acta Chem. Scand. 49 11995) 172.
[36] S. Berger, S. Braun, H.-O. Kalinowski, NMR-Spektroskopie von
Nichtmetallen, 19F-NMR-Spektroskopie, Vol. 4, Georg Thieme,
Stuttgart, 1994.
References
[37] A.Finkel, in: J.C. Tatlow, Peacock, R.D., Hyman, H.H.1Eds.), Advances
in Fluorine Chemistry, Butterworths, London, 1973, pp. 199±203.
[38] W. Gombler, H. Willner, J. Phys. E: Sci. Instrum. 20 11987) 1286.
[39] E.L. Pace, P.E. Hodge, J. Chem. Phys. 58 11973) 2794.
[40] W. Gombler, J. Am. Chem. Soc. 104 11982) 6616.
[1] N. Bartlett, D.H. Lohmann, Proc. Chem. Soc. London 11962) 115.
[2] I.J. Solomon, R.I. Brabets, R.K. Uenishi, J.N. Keith, J.M.
McDonough, Inorg. Chem. 3 11964) 457.
[3] A.J. Edwards, W.E. Falconer, J.E. Griffiths, W.A. Sunder, M.J.
Vasile, J. Chem. Soc., Dalton Trans. 11974) 1129.