Carbenoid reactions of trifluoromethylelement compounds. Part 6. Syntheses and characterization of difluoromethylphosphonium, arsonium and stibonium compounds from reactions of triorganopnicogens with Zn(CF3)Br·2D and Bi(CF3)3</

Article abstract of DOI:10.1016/S0022-1139(99)00018-4

(Difluoromethyl)triorganopnicogenium tetrachlorobismuthates are isolated in moderate to very good yields from the reactions of several R₃E derivatives(E=P, As) with the reagent Bi(CF₃)₃/AlCl₃. (Difluoromethyl)tr

Full text of DOI:10.1016/S0022-1139(99)00018-4

Journal of Fluorine Chemistry 94 (1999) 207±212
Carbenoid reactions of tri¯uoromethylelement compounds. Part 6.
Syntheses and characterization of di¯uoromethylphosphonium,
arsonium and stibonium compounds from reactions of
1
triorganopnicogens with Zn(CF3)BrÁ2D and Bi(CF3)3
N.V. Kirija, S.V. Pasenoka, Yu.L. Yagupolskiia, A. Fitznerb, W. Tyrrab, D. Naumannb,*
aInstitute of Organic Chemistry, National Academy of Sciences of Ukraine, Murmanskaya Str. 5, 253660, Kiev-94, Ukraine
b
È È È È
Institut fur Anorganische Chemie, Universitat zu Koln, Greinstr. 6, D-50939, Koln, Germany
Received 30 October 1998; accepted 5 January 1999
Dedicated to Professor Edgor Niecke on the occasion of his 60th birthday
Abstract
(Di¯uoromethyl)triorganopnicogenium tetrachlorobismuthates are isolated in moderate to very good yields from the reactions of several
R3E derivatives(EˆP, As) with the reagent Bi(CF3)3/AlCl3. (Di¯uoromethyl)triorganopnicogenium bromides are obtained from room
temperature reactions of R3E(EˆP, As, Sb) with Zn(CF3)BrÁ2CH3CN. The compounds were characterized by their NMR and mass spectra
and by comparison with literature data. # 1999 Elsevier Science S.A. All rights reserved.
Keywords: Carbenoid reactions; Di¯uoromethylpnicogenium salts
1. Introduction
containing compounds. On the basis of NMR spectroscopic
studies [3,6], we proved that the reaction must be based on a
two-step mechanism. The ®rst step is the ¯uorine substitu-
tion at the CF3 group still bonded to the metal center
followed by the cleavage of the carbon±metal bond initiated
by protons abstracted from the solvent, especially CH3CN,
where the resulting CH2CN anion may also undergo addition
reactions as shown in the reactions with N-morpholino-
cycloalkenes [7].
Bi(CF3)3 had been shown to react as a tri¯uoromethyl
group transfer reagent [9,10] comparable to Bi(C6H5)3
[11,12] and Bi(C6F5)3 [13±15] which are excellent phenyla-
tion reagents.
Zn(CF3)BrÁ2CH3CN is a versatile tool for the introduction
of di¯uoromethyl groups into organic and inorganic mole-
cules [1]. Similar results were obtained using Cd(CF3)2
complexes [2,3], which are excellent NMR sensors for
the investigation of the basic reaction mechanisms.
On the basis of NMR spectroscopic measurements it was
shown that formation of CF2H groups proceeds via an ionic
pathway by ¯uorine substitution at a CF3 group still bonded
to the metal center rather than via ``free'' di¯uorocarbene,
although this mechanism is proposed for some reactions at
low temperatures [4,5].
Comparative
studies
of
the
reactions
of
In continuation and extension of our prior work on
di¯uoromethylations using tri¯uoromethylmetal com-
pounds, we herein report on the syntheses of (di¯uoro-
methyl)triorganopnicogenium compounds.
Zn(CF3)BrÁ2CH3CN, Cd(CF3)2Á2CH3CN and Bi(CF3)3 with
N(CH3)3 showed that the reactions involving Bi(CF3)3
appear to proceed somewhat differently from the others [6].
In the foregoing papers [7,8] we showed that
Zn(CF3)BrÁ2D, Cd(CF3)2Á2D and Bi(CF3)3 are also excel-
lent starting materials for the generation of di¯uoromethyl-
2. Results and discussion
Three methods have been developed to give di¯uoro-
methylpnicogenium derivatives in suf®cient to very good
yields.
*Corresponding author. Fax: +49-0221-470-5196.
1Part 5, see Ref. [6].
0022-1139/99/$ ± see front matter # 1999 Elsevier Science S.A. All rights reserved.
P I I : S 0 0 2 2 - 1 1 3 9 ( 9 9 ) 0 0 0 1 8 - 4

208
N.V. Kirij et al. / Journal of Fluorine Chemistry 94 (1999) 207±212
2.1. Method A
This reaction again gives evidence for CH3CN being the
source of the proton and implies that ¯uorine substitution
occurs in some cases even in the absence of an auxiliary
acid.
The ®rst method is the reaction of Bi(CF3)3 with the
corresponding triorganopnicogen in the presence of
AlCl3.
‡
BiꢀCF3† ‡ AlCl3 ‡ ER3 ‡ CH3CN ! ‰R3ECF2HŠ
2.2. Method B
3
‡‰BiCl4Š ‡ ‰AlF4Š ‡ CF3H ‡ CF2HCl ‡ Á Á Á
Method B is an extension of our previous work on the use
of Zn(CF3)BrÁ2CH3CN as a source for the formation of
derivatives containing CF2H groups.
The reactions of Zn(CF3)BrÁ2CH3CN with P(C6H5)3,
P[N(C2H5)2]3, As(C6H5)3 and Sb(C6H5)3 proceed in
CH2Cl2 solution at room temperature or below giving the
corresponding(di¯uoromethyl)triorganopnicogenium bro-
mides.
where EˆP, As; RˆC6H5, n-C4H9, C2H5, N(C2H5)2.
However, the mechanism is still not completely under-
stood. The formation of the tetrachlorobismuthate anion and
maximum yields of approximately 75% on the basis of the
amount of Bi(CF3)3 involved even in those cases when the
base is added in excess clearly demonstrates that only one
CF3 group of Bi(CF3)3 is converted into the CF2H group.
The remaining CF3 groups are converted into CF3H as the
major product and smaller quantities of CF2HCl are formed.
The resonance of a further CF2H compound is detected in
the 19F-NMR spectra of all reaction mixtures as a doublet at
ZnꢀCF3†Br Á 2CH3CN ‡ ER3 ! ‰R3ECF2HŠBr
‡hZnFꢀCH2CN†i ‡ CH3CN
where EˆP (81% yield), As (84% yield), Sb (3% yield);
ca. 95 ppm, with a J(19F±1H) coupling of 62Æ2 Hz. On
2
RˆC6H5.
the basis of literature data [18] this must be assigned to a
CF2H-substituted amine derived from the solvent acetoni-
trile. Involvement of CH3CN in these types of reactions
especially as a source of protons has been established in
reactions in CD3CN and in consecutive experiments [2,3,7].
The residue which precipitated was only roughly ana-
lyzed. [AlF4] could be unambiguously identi®ed on the
basis of 19F- and 27Al-NMR spectra [16,17].
However, the reaction of P[N(C2H5)2]3 yielded a surpris-
ing result. The products obtained were a nearly 1:1 mixture
of {[(C2H5)2N)]3P(CF2H)}Br (40%) and [(C2H5)2N]2-
P(CF2H)F2 (42%).
ZnꢀCF3†Br Á 2CH3CN ‡ ‰ꢀC2H5†2NŠ P
! f‰ꢀC2H5† NŠ PꢀCF2H†gBr ‡ ‰ꢀ3C2H5† NŠ PꢀCF2H†F2
2
3
2
2
The formation of the di¯uorophosphorane must be con-
sidered as a double exchange of bromide and diethylamide
by intermediately formed zinc ¯uorides [21]. The reactions
of Zn(CF3)BrÁ2CH3CN and (C6H5)3As and (C6H5)3Sb,
respectively, were studied as examples at room temperature
without an additional acid or base giving
[(C6H5)3As(CF2H)]Br in very good yield (84%), whereas
only traces of [(C6H5)3Sb(CF2H)]Br were isolated. Reac-
tions with Bi(C6H5)3 did not give any evidence for the
formation of [(C6H5)3Bi(CF2H)] compounds.
Reactions of AlX3 with Cd(CF3)2 complexes,
Zn(CF3)BrÁ2CH3CN and Bi(CF3)3 in the absence of strong
bases proceed more-or-less indiscriminately yielding sev-
eral unidenti®ed ¯uorine-containing compounds [19].
Thus, the synthetic potential of Bi(CF3)3 in the systems
investigated must be considered to be of great interest.
[(C6H5)3P(CF2H)][BiCl4],
[(n-C4H9)3P(CF2H)][BiCl4]
and [(C2H5)3As(CF2H)][BiCl4] were obtained by this
method on a preparative scale in good yields with compara-
tive ease.
The addition of BF3 to the reactants as used in the
synthesis of group 16 derivatives [2] effects an acceleration
of the reaction together with formation of a couple of by-
products.
The ®rst symmetric diphosphonium derivative was
obtained from the reaction with 1,2-bis(diphenylphosphi-
no)ethane in 74% yield. However, elemental analysis as
well as 19F-NMR data indicate that the product obtained
also contained a low amount of the monodi¯uoromethylated
compound and possibly a di¯uoromethylphosphane.
The reaction of Bi(CF3)3 and P[N(C2H5)2]3, the strongest
base in this series, was performed in the absence of AlCl3.
After stirring equimolar amounts of both derivatives in
CH3CN at ambient temperature for 24 h, an unidenti®ed
residue precipitated. After ®ltration, the mother liquor was
diluted with diethyl ether and distilled off together with
CH3CN. The remaining solid was dried in vacuo giving
{[(C2H5)2N]3P(CF2H)}[HF2] in 61% yield. The NMR
values agree with literature data [20].
2.3. Method C
Although the reaction of E(C6H5)3 (EˆP, As, Sb) and
Zn(CF3)BrÁ2CH3CN proceeded without an additional auxi-
liary acid, reactions of Zn(CF3)BrÁ2ER3 in the presence of
AlCl3ÁER3 were tested.
The 1:1 adducts of ER3 (EˆAs, Sb; RˆC2H5, C6H5) and
the Lewis-acid (AlCl3 or BF3) were prepared in advance in
CH2Cl2 solution by combining both reactants. The adducts
were formed in exothermal reactions and the adducts with
E(C2H5)3 were characterized on the basis of their 1H-NMR
spectra (Table 1).
‰ꢀC2H5†2NŠ3P ‡ BiꢀCF3†
3
! f‰ꢀC2H5†2NŠ3PCF2Hg‰HF2Š ‡ Á Á Á

N.V. Kirij et al. / Journal of Fluorine Chemistry 94 (1999) 207±212
209
Table 1
1H-NMR data of the 1:1 adducts of E(C2H5)3 (EˆAs, Sb) and BF3 or
On the basis of NMR spectroscopic measurements the
triphenyl derivatives appear to be salt-like compounds in
solution, dissociating into [(C6H5)3E(CF2H)] and Br
AlCl3 (CH2Cl2, 208C)
‡
E
As
Sb
ions. Therefore, the(di¯uoromethyl)triphenyl derivatives
must be suggested as tetrahedral tetraorganopnicogenium
bromides without signi®cant cation anion interaction in
solution.
ꢀ(CH2)
ꢀ(CH3)
ꢀ(CH2)
1.27
ꢀ(CH3)
E(C2H5)3
1.07
1.70
1.65
0.79
1.16
1.15
1.24
a
E(C2H5)3ÁBF3
In contrast, the ethyl derivatives appear to be covalent
1
E(C2H5)3ÁAlCl3
1.50
1.15
compounds. The H- and 13C-NMR spectra of the triethyl
a
19F-NMR: ꢀ(BF3)ˆ 125 ppm, broad.
derivatives suggest that covalent trigonal bipyramidal spe-
cies with two magnetically inequivalent ethyl groups have
been formed. However, the NMR data are in contrast to the
VSEPR model [22], which predicts that the most electro-
negative ligands, i.e. CF2H and Br, should occupy axial
positions. On the basis of the NMR measurements and the
Also the 1:2 adducts of Zn(CF3)BrÁ2ER3 (EˆAs, Sb;
RˆC2H5, C6H5) were prepared in advance by adding the
corresponding arsenic or antimony compound to a solution
of Zn(CF3)BrÁ2CH3CN in CH2Cl2. The formation of the
adducts is indicated by a signi®cant low®eld shift of the
¯uorine resonances of Zn(CF3)Br/Zn(CF3)2 of ca. 3±4 ppm.
Combining the two solutions gave an exothermal reac-
tion. Stirring overnight led to the formation of the corre-
sponding CF2H derivatives. The reaction was terminated
after approximately 16 h of stirring by adding a saturated
solution of NH4Br in ethanol or an aqueous HCl solution.
Excess Zn(CF3)Br was converted into CF3H and ZnBrX
(XˆCl, Br) by this step; intermediates with structural units
[XZnCF2E(C2H5)3]Br or [XZnCF2E(C6H5)3]Br were con-
verted into the corresponding di¯uoromethyl arsonium and
stibonium compounds, respectively.
‡
detection of the M peak in the mass spectrum, a covalent
compound consisting of two isomers like
might be assumed, whereas the corresponding (di¯uoro-
methyl)triethylarsonium tetrachlorobismuthate appears to
be an ionic species in solution and in the solid state.
ZnꢀCF3†Br Á 2ER3 ‡ MX3 Á ER3
! ‰Br Zn CF2 ER3Š‰MX3FŠ
3. Experimental
!
NH Br=C H OH Br Zn Br ‡ MꢀOC2H5†
4
2
5
All reactions were carried out in a dry nitrogen atmo-
sphere using Schlenk techniques. Commercially available
phosphines and arsines were used after puri®cation by
common methods. AlCl3 was carefully dried in vacuo
before use.
3
‡ ‰R3EꢀCF2H†ŠBr
where MX3ˆAlCl3, BF3; EˆAs, Sb; RˆC2H5, C6H5.
The intermediates in these reactions, [XZnCF2ER3]Br
were detected in the 19F-NMR spectra (ꢀ(ZnCF2As)
92Æ1 ppm, ꢀ(ZnCF2Sb) 88Æ1 ppm, cf. [6] for the cor-
responding ammonium intermediates).
The yields of the products were between 30% and 33%
for the arsenic compounds and only traces for the antimony
derivatives due to complicated work up of the reaction
mixtures.
Zn(CF3)BrÁ2CH3CN was prepared according to Ref.
[23]; Bi(CF3)3 according to Ref. [24,25].
As(C2H5)3 was prepared according to Ref. [26];
Sb(C2H5)3 by analogy with Ref. [27].
The adducts of BF3ÁAs(C2H5)3, AlCl3ÁE(C2H5)3 (EˆAs,
Sb) were prepared in CH2Cl2 solution and used as obtained
1
after H-NMR spectroscopic control (Table 1).
The adducts Zn(CF3)BrÁ2ER3 were prepared in advance
adding the corresponding triorganopnicogen compound to a
well-stirred solution of Zn(CF3)BrÁ2CH3CN in CH2Cl2 at
room temperature. The exchange was monitored by
Thus, the formation, especially of the arsenic derivative,
reveals that a self-dissociation of Zn(CF3)Br complexes
occurs even at room temperature according to
2
3
‡
19F-NMR spectroscopy,
a signi®cant low®eld shift
D
j
6
6
7
7
7
5
indicated the formation of the adducts. Isolation of the
new adducts and use as starting materials in separate reac-
tions did not give better yields or a more convenient working
up.
NMR spectra were recorded on Bruker spectrometers
operating at 200 or 300 MHz. CCl3F [19F], (CH3)4Si
[1H, 13C] and H3PO4 (85%) [31P] were used as external
standards. Electron impact (EI) mass spectra were run on a
modi®ed Varian MAT CH5 spectrometer.
ZnꢀCF †Br Á 2D ! Br ZnCF
‡F
6
3
2
4
j
D
As already suggested previously, the electron de®ciency
at the M CF2 group is compensated by a base, i.e. ER3.
Proton abstraction from CH3CN or the addition of a proton
source, i.e. NH4 , C2H5OH, H2O ®nally gives the corre-
sponding di¯uoromethylpnicogen derivative.
‡
‡

210
N.V. Kirij et al. / Journal of Fluorine Chemistry 94 (1999) 207±212
Fluorine was analyzed according to Ref. [28], chlorine
according to Ref. [29] and bismuth according to Ref. [30].
3.1.3. 1,2-Bis((difluoromethyl)diphenylphosphonio)ethane
bis(tetrachlorobismuthate)
The compound was obtained by the same method from
1.00 g (2.40 mmol) Bi(CF3)3, 0.48 g (1.20 mmol) 1,2-bis-
(diphenylphosphano)ethane and 0.48 g (3.60 mmol) AlCl3.
After evaporation of CH3CN, the precipitate was recrystal-
lized from acetone to give 0.89 g (74%) 1,2-bis((di¯uoro-
3.1. Method A
3.1.1. (Difluoromethyl)triphenylphosphonium
tetrachlorobismuthate
To a solution of 0.6 g (1.44 mmol) Bi(CF3)3 and 0.38 g
(1.45 mmol) triphenylphosphine in 5 ml acetonitrile, 0.32 g
(2.40 mmol) AlCl3 was added at 408C. The reaction
mixture was stirred for 1 h at 208C and then for 2 h at
ambient temperature. The precipitate was ®ltered off and the
solvent was distilled off under reduced pressure. After
distillation, the precipitate was recrystallized from acetone
to give 0.74 g (77% relative to Bi(CF3)3) (di¯uoromethyl)-
triphenylphosphonium tetrachlorobismuthate decomposing
at ca. 2008C.
methyl)diphenylphosphonio)ethane
a
mono(di¯uoromethyl) compound and a further di¯uoro-
methylphosphorus compound.
bis(tetrachlorobis-
muthate) containing low percentage of the
Elemental analysis for C28H26Bi2Cl8F4P2: [found (calcu-
lated)] Bi 34.41% (34.77%), Cl 23.17% (23.60%), F 5.94%
(6.32%).
19F-NMR (CD3CN): ꢀ 127.4 ppm, m, 2J(19F±1H)ˆ
2
46.4 Hz, J(31P±19F)ˆ79.2 Hz.
1H-NMR (CH3CN): ꢀ(C6H5, CF2H) 7.00±7.35 ppm,
overlapping signals, ꢀ(CH2) 2.05 ppm, t, 3J(31P±1H)ˆ
4.4 Hz.
Elemental analysis for C19H16BiCl4F2P: [found (calcu-
lated)] Bi 31.08% (31.48%), Cl 20.97% (21.35%), F 5.29%
(5.72%). 19F-NMR ((CD3)2SO): ꢀ
126.06 ppm, dd,
2J(19F±1H)ˆ46.7 Hz, 2J(31P±19F)ˆ78.1 Hz; (CH3CN) ꢀ
125.15 ppm, dd, 2J(19F±1H)ˆ47.2 Hz, 2J(31P±19F)ˆ
78.3 Hz.
3.1.4. (Difluoromethyl)triethylarsonium
tetrachlorobismuthate
The compound was obtained from 0.60 g (1.44 mmol)
Bi(CF3)3, 0.70 g (4.32 mmol) (C2H5)3As and 0.57 g
(4.27 mmol) AlCl3 in 78% yield (0.63 g relative to
Bi(CF3)3) as solid decomposing above 2008C.
Elemental analysis for C7H16AsBiCl4F2: [found (calcu-
lated)] Bi 36.78% (37.06%), Cl 25.41% (25.15%), F 6.39%
(6.74%).
The 19F-NMR data are in good agreement with those
given in [20].
1H-NMR (CD3CN): ꢀ(C6H5, CF2H) 7.79±7.85 ppm,
overlapping signals.
2
31P{1H}-NMR (CH3CN): ꢀ ‡22.3 ppm, t, J(31P±19F)ˆ
77.3 Hz.
13C{1H}-NMR (CH3CN): ꢀ(C-1) 113.99 ppm, 1J(31P±
13C)ˆ85.2 Hz, ꢀ(CF2H) 116.40 ppm, 1J(19F±13C)ˆ
269.6 Hz, 1J(31P±13C)ˆ56.5 Hz, ꢀ(C-3,5) 132.97 ppm,
19F-NMR (CH3CN): ꢀ 119.2 ppm, d, 2J(19F±1H)ˆ
48.7 Hz.
2
3J(31P±13C)ˆ12.7 Hz, ꢀ(C-2,6) 136.84 ppm, J(31P±13C)ˆ
3.1.5. (Difluoromethyl)tris(diethylamino)phosphonium
bifluoride
10.2 Hz, ꢀ(C-4) 138.90 ppm, 4J(31P±13C)ˆ2.5 Hz.
The ring-carbon resonances were assigned by analogy
with Ref. [31].
A solution of 0.52 g (1.25 mmol) Bi(CF3)3 and 0.30 g
(1.21 mmol) [(C2H5)2N]3P in 5 ml CH3CN was stirred for
24 h at ambient temperature. The precipitate was ®ltered off
and the solvent was diluted with diethylether. The residue
obtained after solvent evaporation was dried in vacuo. The
yield was 0.25 g (61% relative to [(C2H5)2N]3P). The
spectral data correspond with those given in Ref. [20].
The resonance of the [HF2] anion was detected in the
19F-NMR spectrum at ꢀ 148 to 149 ppm as a broad
unresolved signal.
3.1.2. (Difluoromethyl)-n-tributylphosphonium
tetrachlorobismuthate
Obtained by the same method from 0.57 g (1.37 mmol)
Bi(CF3)3, 0.26 g (1.29 mmol) (n-C4H9)3P and 0.26 g
(1.95 mmol) AlCl3. After distilling off CH3CN, the pre-
cipitate was recrystallized from acetone to give 0.60 g (77%
relative to (n-C4H9)3P) (di¯uoromethyl)-n-tributylphospho-
nium tetrachlorobismuthate which decomposed above
2008C.
Elemental analysis for C13H28BiCl4F2P: [found (calcu-
lated)] Bi 34.15% (34.59%), Cl 23.02% (23.47%).
19F-NMR (CD3CN): ꢀ 127.7 ppm, dd, 2J(19F±1H)ˆ
3.2. Method B
3.2.1. (Difluoromethyl)triphenylphosphonium bromide
A solution of 0.89 g (3.00 mmol) Zn(CF3)BrÁ2CH3CN
and 0.89 g (3.39 mmol) (C6H5)3P in 10 ml dichloromethane
was stirred for 48 h at ambient temperature. The precipitate
was ®ltered and the solvent was distilled off at reduced
pressure. After evaporation of CH2Cl2 the precipitate was
washed with a CH2Cl2/(C2H5)2O mixture and dried in high
vacuo. The yield was 0.95 g (81% relative to
2
47.4 Hz, J(31P±19F)ˆ67.0 Hz.
1H-NMR (CD3CN): ꢀ(CH3) 0.93 ppm, 9H, ꢀ(b, g-CH2)
1.53 ppm, 12H, ꢀ(a-CH2) 2.52 ppm, 6H, ꢀ(CF2H)
7.27 ppm, dt, 2J(19F±1H)ˆ47.4 Hz, 2J(31P±1H)ˆ27.2 Hz
1H.
31P-NMR (CD3CN): ꢀ ‡39.32 ppm, t, 2J(31P±19F)ˆ
67.1 Hz.

N.V. Kirij et al. / Journal of Fluorine Chemistry 94 (1999) 207±212
211
Zn(CF3)BrÁ2CH3CN). M.p. 200±2028C. The spectroscopic
resulted. The mixture was stirred for 1 h until the reaction
mixture had cooled to ambient temperature. A solution
data were identical with those given above.
(suspension)
of
Zn(CF)3BrÁ2As(C2H5)3
(10.54 g
3.2.2. (Difluoromethyl)tris(diethylamino)phosphonium
bromide and (difluoromethyl)bis-
(diethylamino)difluorophosphorane
(19.57 mmol) in 20 ml CH2Cl2) was slowly dropped into
the solution of AlCl3ÁAs(C2H5)3 when a strong exothermal
reaction with evolution of gaseous products started. Stirring
overnight gave a brown solution from which some white
solid precipitated. 19F-NMR spectroscopic control showed
A solution of 1.20 g (4.85 mmol) [(C2H5)2N]3P and
3.17 g (10.69 mmol) Zn(CF3)BrÁ2CH3CN in 20 ml dichloro-
methane was stirred for 24 h at ambient temperature. The
precipitate was ®ltered off, and the solvent was distilled off
under reduced pressure. After distilling off CH2Cl2, the
precipitate was washed with diethylether and dried in high
vacuo. The yield of (di¯uoromethyl)tris(diethylamino)pho-
sphonium bromide was 0.74 g (40%). The analytical and
spectral data correspond fairly well with those given in [20].
After diethylether evaporation (di¯uoromethyl)bis(diethyl-
amino)di¯uorophosphorane was obtained as a colourless
oil. The yield was 0.54 g (42%).
‡
the resonances of [(C2H5)3As(CF2H)] , [(C2H5)3AsCF2-
‡
ZnX] , Zn(CF3)X as well as low intensity resonances of
Zn(C2F5)-derivatives. The reaction was terminated by addi-
tion of 20 ml of a saturated ethanolic NH4Br solution or an
aqueous HCl solution (10 ml) to decompose unreacted
‡
Zn(CF3)Br complexes and convert [(C2H5)3AsCF2ZnX]
into the di¯uoromethyl derivative. The mixture was heated
for 24 h at 808C. After precipitation of the solid products the
solution was decanted. The residue was suspended in
CH2Cl2; insoluble components were ®ltered off. The
organic fractions were combined, and all volatile compo-
nents were distilled off in vacuo until a brown solid
remained. The solid was eluated by column chromatogra-
phy (Al2O3, length of the column 10 cm, diameter 4 cm).
Eluation was started with a 10:1 mixture of CH2Cl2 and
ethylacetate. The ratio was varied to 1:1. (Di¯uoromethyl)-
triethylarsonium bromide ®nally was eluated using a
CH2Cl2/CH3OH mixture (5:1 v/v). The dark brown fraction
was dried in vacuo until a brown solid was obtained which
was washed with hot water to give a yellow aqueous
solution.
After drying in vacuo, the product was washed with
ethylacetate and recrystallized from aqueous methanol
(1:1 v/v). [(C2H5)3As(CF2H)]Br crystallized as colourless
or light brownish crystals of up to 10 mm length. The yield
was 1.89 g (33% relative to Zn(CF3)BrÁ2As(C2H5)3).
A similar procedure was used for all other arsenic and
antimony compounds.
Elemental analysis for C9H21F4N2P: [found (calculated)]
F 28.65% (28.76%).
19F-NMR[(C2H5)2O]:ꢀ(PF2) 66.86 ppm,d,1J(31P±19F)ˆ
2
1
771 Hz, ꢀ(CF2H) 127.70 ppm, ddt, J(19F± H)ˆ 52 Hz,
2J(31P±19F)ˆ110 Hz, 3J(19F±19F)ˆ10.5 Hz.
31P-NMR [CH2Cl2]: ꢀ 66.67 ppm, ttd, 1J(31P±19F)ˆ
771 Hz, J(31P±19F)ˆ110 Hz, J(31P±1H)ˆ35 Hz.
1H-NMR[(CD3)2CO]:ꢀ(CF2H)5.9 ppm,tdt,2J(19F±1H)ˆ
52 Hz, 2J(31P±1H)ˆ35 Hz, 3J(19F±1H)ˆ6.5 Hz.
2
2
MS (20 eV, 308C): 264 (29%, {[(C2H5)2N]2P(F2)-
‡
‡
CF2H} ), 213 (47%, f‰ꢀC2H5†2NŠ2PF2 g†, 192 (100%,
‡
‡
{(C2H5)2NP(F2)CF2H }), 122 (24%, {(C2H5)2NPF} ),
72 (48%, {(C2H5)2N} ).
‡
3.2.3. (Difluoromethyl)triphenylarsonium bromide
(Di¯uoromethyl)triphenylarsonium
bromide
was
obtained from 1.00 g (3.27 mmol) (C6H5)3As and 3.00 g
(10.12 mmol) Zn(CF3)BrÁ2CH3CN in 84% yield (1.20 g).
M.p. 2008C (dec.).
Elemental analysis for C19H16AsBrF2: [found (calcu-
lated)] F 8.26% (8.69%).
19F-NMR [CH2Cl2]: ꢀ 115.4 ppm, d, 2J(19F±1H)ˆ
48.7 Hz.
The analytical data are summarized in the following
section.
(C2H5)3As(CF2H)Br. Yield 33%; light brownish crystals.
19F-NMR [CD3CN]: ꢀ(CF2H) 118.0 ppm, 2J(19F±1H)ˆ
1
1
48 Hz, J(19F±13C)ˆ282 Hz, Á(12=13C±19F) 0.143 ppm.
1H-NMR [CD3CN]: ꢀ(CF2H) 7.7 ppm, t, J(19F±1H)ˆ
2
3.2.4. (Difluoromethyl)triphenylstibonium bromide
Prepared from 1.20 g (3.40 mmol) (C6H5)3Sb and 3.00 g
(10.12 mmol) Zn(CF3)BrÁ2CH3CN. After working up (see
above) only ca. 0.05 g (ca. 3%) of [(C6H5)3SbCF2H]Br were
obtained as a grayish solid. The NMR-data correspond with
those given below.
48 Hz; ꢀ(CH2(ax)) 2.7 ppm, q; ꢀ(CH2(eq)) 1.9 ppm, q;
ꢀ(CH3(ax)) 1.3 ppm, t; ꢀ(CH3(eq)) 1.1 ppm, t.
13C{1H}-NMR [CD3CN]: ꢀ(CF2H) 120.0 ppm, t, 1J(19F±
13C)ˆ282 Hz; ꢀ(CH2) 21.8 and 15.5 ppm; ꢀ(CH3) 8.0 and
7.0 ppm. An assignment to axial or equatorial positions
could not be made on the basis of decoupled spectra due to
NOE-effects in¯uencing intensity and integration.
‡
3.3. Method C
MS (20 eV, 1608C): 292 (1%, M ), 263 (1%,
[As(C2H5)2(CF2H)Br] ), 241 (3%, [As(C2H5)3Br] ), 234
‡
‡
‡
A typical procedure is given for the reaction of
Zn(CF3)BrÁ2As(C2H5)3 and AlCl3ÁAs(C2H5)3.
(1%, [As(C2H5)(CF2H)Br] ), 213 (10%, [As(C2H5)3-
‡
‡
(CF2H)] ), 184 (10%, [As(C2H5)2(CF2H)] ), 162 (15%,
‡ ‡
In a Schlenk-tube 3.25 g (20.05 mmol) As(C2H5)3 were
dissolved in 20 ml CH2Cl2 at ambient temperature. 2.67 g
(20.02 mmol) of AlCl3 were added. An exothermal reaction
[As(C2H5)3] ), 154 (1%, [AsBr] ), 133 (100%,
‡
‡
[As(C2H5)2] ), 108 (5%, [C2H5Br] ), 104 (45%,
‡
‡
‡
[As(C2H5)] ), 79 (3%, [Br] ), 51 (10%, [CF2H] ).

212
N.V. Kirij et al. / Journal of Fluorine Chemistry 94 (1999) 207±212
[(C6H5)3As(CF2H)]Br. Yield 30%, white microcrystal-
line solid.
acknowledged. N.V.K. and Yu.L.Ya. thank the Deutschen
Forschungsgemeinschaft, SVP thanks the Heinrich-Hertz-
Stiftung for grants.
19F-NMR [(CD3)2CO]: ꢀ(CF2H)
115.0 ppm, d,
2J(19F±1H)ˆ48 Hz, 1J(19F±13C)ˆ288 Hz, 1Á(12=13C±19F)
0.135 ppm.
1H-NMR [(CD3)2CO]: ꢀ(CF2H) 7.9 ppm, t, 2J(19F±1H)ˆ
48 Hz, 1H, ꢀ(C6H5) 7.6 ppm, overlapping multiplets, 15H.
13C{1H}-NMR [(CD3)2CO]: ꢀ(C-4) 137.0 ppm; ꢀ(C-2,6)
133.0 ppm; ꢀ(C-3,5) 131.0 ppm; ꢀ(CF2H) 117.0 ppm, t,
1J(19F±13C)ˆ288 Hz. C-1 was not observed due to line
broadening caused by the quadrupole resonance of the
arsenic nucleus.
References
[1] W. Tyrra, D. Naumann, J. Prakt. Chem. 338 (1996) 283.
È
[2] D. Naumann, R. Mockel, W. Tyrra, Angew. Chem., Int. Ed. Engl. 33
(1994) 323.
È
[3] R. Mockel, W. Tyrra, D. Naumann, J. Fluorine Chem. 73 (1995) 229.
[4] R. Eujen, B. Hoge, J. Organomet. Chem. 503 (1995) C51.
[5] L.J. Krause, J.A. Morrison, J. Am. Chem. Soc. 103 (1981) 2995.
[6] S.V. Pasenok, N.V. Kirij, Yu.L. Yagupolskii, D. Naumann, W. Tyrra,
A. Fitzner, Z. Anorg. Allg. Chem., in press.
‡
MS (20 eV, 1608C): 306 (45%, [As(C6H5)3] ), 229 (10%,
[As(C6H5)2] ), 154 (10%, [AsBr] ), 152 (100%,
‡
‡
‡
‡
[7] W. Tyrra, D. Naumann, S.V. Pasenok, Yu.L. Yagupolskii, J. Fluorine
Chem. 70 (1995) 181.
[AsC6H5] ), 51 (20%, [CF2H] ).
The mass spectrometric breakdown pattern with the
exception of the ions 154 and 51 corresponds with that
for As(C6H5)3 [32].
[8] R. Miethchen, M. Hein, D. Naumann, W. Tyrra, Liebigs Ann. (1995)
1717.
[9] W. Tyrra, D. Naumann, Can. J. Chem. 69 (1991) 327.
[10] W. Tyrra, D. Naumann, Can. J. Chem. 67 (1989) 1949.
[11] R.A. Abramovitch, D.H.R. Barton, J.-P. Finet, Tetrahedron 44 (1988)
3039.
(C2H5)3Sb(CF2H)Br. Yield: traces; colourless solid.
19F-NMR[CH2Cl2]:ꢀ(CF2H) 115.1 ppm,d,2J(19F±1H)ˆ
48 Hz, 1J(19F±13C)ˆ282.5 Hz.
[12] J.-P. Finet, Chem. Rev. 89 (1989) 1487.
[13] A.O. Miller, G.G. Furin, Izv. Akad. Nauk, Ser. Khim. (1994) 171.
[14] A.O. Miller, G.G. Furin, Russ. Chem. Bull. 43 (1994) 168.
2
1H-NMR [CH2Cl2]: ꢀ(CF2H) 6.72 ppm, t, J(19F±1H)ˆ
48 Hz, ꢀ(CH2) 2.40 and 2.24 ppm, q, ꢀ(CH3) 1.40 and
1.37 ppm, t. A ®nal assignment could not be made due to
overlapping signals.
È È
[15] H.J. Frohn, S. Gorg, G. Henkel, M. Lage, Z. Anorg. Allg. Chem. 621
(1995) 1251.
[16] N. Herron, D.L. Thorn, R.L. Harlow, F. Davidson, J. Am. Chem. Soc.
115 (1993) 3028.
13C-NMR [CH2Cl2]: ꢀ(CF2H) 115.0 ppm, t, 1J(19F±13C)ˆ
283 Hz. The signals of the CH3CH2 groups are located
between 20 and 0 ppm but broadened and partially split due
to unsuccessful decoupling.
È
[17] W. Tyrra, Dissertation, Universitat Dortmund, 1989.
[18] D.J. Brauer, H. BuÈrger, M. Grunwald, G. Pawelke, J. Wilke, Z.
Anorg. Allg. Chem. 537 (1986) 63.
‡
[19] R.Yu. Garlyauskajte, W. Tyrra, unpublished results.
[20] M.J. van Hamme, D.J. Burton, P.E. Greenlimb III, Org. Magn. Res.
11 (1978) 275.
MS (20 eV, 858C): 338 (1%, M ), 295 (10%, [Sb(C2H5)-
(CH3)(CF2H)Br] ), 280 (5%, [Sb(C2H5)(CF2H)Br] ), 259
‡
‡
‡
‡
(20%, [Sb(C2H5)3(CF2H)] ), 251 (60%, [Sb(CF2H)Br] ),
‡
[21] R. Bartsch, O. Stelzer, R. Schmutzler, Z. Naturforsch. 36b (1981)
1349.
244
(100%,
[Sb(C2H5)(CH3)Br] ), 230
‡
[Sb(C2H5)2(CF2H)] ), 215 (12%, [Sb(CH3)Br] ), 208
(40%,
‡
[22] J.E. Huheey, Anorganische Chemie, Walter de Gruyter, Berlin, Aufl.,
1988, p. 222.
‡
‡
(11%, [Sb(C2H5)3] ), 201 (4%, [Sb(C2H5)(CF2H)] ), 179
‡
[23] D. Naumann, W. Tyrra, B. Kock, W. Rudolph, B. Wilkes, J. Fluorine
Chem. 67 (1994) 91.
‡
(61%, [Sb(C2H5)2] ), 150 (49%, [Sb(C2H5)] ), 121 (3%,
‡
[Sb] ).
[24] W. Tyrra, D. Naumann, J. Organomet. Chem. 334 (1987) 323.
[25] D. Naumann, R. Schlengermann, W. Tyrra, J. Fluorine Chem. 66
(1994) 79.
[(C6H5)3Sb(CF2H)]Br. The yield was extremely low;
only the 19F-NMR spectrum could be recorded.
19F-NMR[CH2Cl2]:ꢀ(CF2H) 106.1 ppm,d,2J(19F±13C)ˆ
47 Hz, 1J(19F±13C)ˆ300 Hz.
[26] W. Steinkopf, J. MuÈller, Chem. Ber. 54 (1921) 841.
[27] W.J.C. Dyke, W.C. Davies, W.J. Jones, J. Chem. Soc. (1930) 463.
[28] A.D. Campbell, P.A. Dawson, Mikrochim. Acta (1983) 489.
[29] G. Jander, K.F. Jahr, H. Knoll, Maûanalyse, Walter deGruyter,
Berlin, 1973, p. 300.
[30] R. Pribil, Komplexone in der Chemischen Analyse, Verlag der
Wissenschaften, Berlin, 1961.
Acknowledgements
[31] G.A. Gray, J. Am. Chem. Soc. 95 (1973) 7736.
[32] C. Glidewell, J. Organomet. Chem. 116 (1976) 199.
Financial support by the Fonds der Chemischen Industrie,
the Deutsche Forschungsgemeinschaft (DFG) and the
Ukrainian Ministry of Science and Technology is gratefully