H.-J. Frohn et al. / Journal of Fluorine Chemistry 131 (2010) 969–974
973
(85 mg, 0.32 mmol) in 1,1,2-C2Cl3F3 (0.5 mL) and PFB (1.4 mL) and
cooled to ꢁ20 8C. Then a cold (ꢁ20 8C) solution of C6F5BF2
(0.32 mmol) in PFB (0.4 mL) was added in portions. The colorless
solution was stirred at ꢁ20 8C for 1 h and evaporated to dryness in
vacuum at 20 8C. The residue was washed with CCl3F (2 ꢇ 3 mL) at
15 8C and the solid was dried in vacuum at 20 8C to yield
[4-CF3C6H4(C6F5)Br][BF4] (145 mg, 94%).
B. A solution of 4-CF3C6H4BrF2 (0.13 mmol) in CH3CN (0.9 mL)
was added in portions to a solution of C6F5BF2 (0.13 mmol) in PFB
(0.4 mL) and CH3CN (1 mL). The solution was stirred at 24 8C for
10 min. The 19F NMR spectrum showed the formation of
[4-CF3C6H4(C6F5)Br][BF4] in nearly quantitative yield besides
traces of 4-CF3C6H4Br and C6F5H.
(0.8 mL) was added in portions. After 10–15 min
a
white
suspension was formed. It was stirred at ꢁ40 8C for 2 h. The 19F
NMR spectrum (ꢁ10 8C) of the colorless mother liquor showed
signals of [trans-CF3CF55CFBF3]–, C6F5Br, cyclo-1-Br-1,4-C6F7, cy-
clo-1-BrC6F9, and [C6F5(trans-CF3CF55CF)Br]+ (resonances at ꢁ67.2
(dd, 3J(F3, F2) = 10 Hz, 4J(F3, F1) = 19 Hz, 3F, F3), ꢁ109.7 (qd, 4J(F1,
F3) = 19 Hz, 3J(F1, F2) = 131 Hz, 1F, F1), ꢁ136.8 (d, 3J(F2,
F1) = 131 Hz, 1F, F2), ꢁ127.1 (m, 2F, F2,6), ꢁ134.6 (tt, 3J(F4,
F3,5) = 19 Hz, 4J(F4, F2,6) = 10 Hz, 1F, F4), and ꢁ152.5 (m, 2F, F3,5
)
ppm). All volatiles were removed in vacuum at ꢁ10 8C to yield
the white salt [C6F5(trans-CF3CF55CF)Br][trans-CF3CF55CFBF3]
(57 mg).
[C6F5(trans-CF3CF55CF)Br][trans-CF3CF55CFBF3] (14). 11B NMR
[4-CF3C6H4(C6F5)Br][BF4] (4c). 1H NMR (CH3CN, 24 8C):
d
8.24
(CH3CN, 24 8C):
d
ꢁ0.5 (dq, 2J(B, F1) = 26 Hz, 1J(B, F) = 40 Hz, [trans-
and 8.21, 7.98 and 7.96 (AA0BB0, 4H). 11B NMR (CH3CN, 24 8C):
d
CF3CF55CFBF3]ꢁ). 19F NMR (CH3CN, ꢁ10 8C):
d
ꢁ68.0 (dd, 3J(F3,
ꢁ1.6 (s, Dn1/2 = 2 Hz, [BF4]–). 19F NMR (CH3CN, 24 8C):
d
ꢁ62.9
F2) = 11 Hz, 4J(F3, F1) = 19 Hz, 3F, F3), ꢁ109.4 (qdt, 4J(F1, F3) = 19 Hz,
3J(F1, F2) = 130 Hz, 5J(F1, F2,6) = 4 Hz, 1F, F1), ꢁ140.9 (tqd, 6J(F2,
F2,6) = 7 Hz, 3J(F2, F3) = 11 Hz, 3J(F2, F1) = 130 Hz, 1F, F2), ꢁ128.8 (m,
2F, F2,6), ꢁ137.9 (tt, 3J(F4, F3,5) = 21 Hz, 4J(F4, F2,6) = 8 Hz, 1F, F4),
ꢁ154.3 (m, 2F, F3,5) [trans-CF3CF55CF(C6F5)Br]+; ꢁ66.9 (qdd, 5J(F3,
BF3) = 1 Hz, 3J(F3, F2) = 11 Hz, 4J(F3, F1) = 23 Hz, 3F, F3), ꢁ156.0 (d,
3J(F1, F2) = 130 Hz, 1F, F1), ꢁ179.9 (d, 3J(F2, F1) = 130 Hz, 1F, F2),
ꢁ143.4 (dq, 4J(BF3, F2) = 8 Hz, 1J(F, B) = 40 Hz, 3F, BF3ꢁ) ([trans-
CF3CF55CFBF3]ꢁ).
(s, 3F, CF3), ꢁ131.0 (m, 2F, F2,6), ꢁ141.6 (tt, 3J(F4, F3,5) = 20 Hz, 4J(F4,
F2,6) = 7 Hz, 1F, F4), ꢁ156.1 (m, 2F, F3,5), ꢁ149.9 (s, 4F, [BF4]ꢁ). 1H
NMR (PFB/1,1,2-C2Cl3F3):
d
8.22 and 8.20, 7.88 and 7.84 (AA0BB0,
4H). 11B NMR (PFB/1,1,2-C2Cl3F3):
19F NMR (PFB/1,1,2-C2Cl3F3):
d
ꢁ2.1 (s, Dn1/2 = 5 Hz, [BF4]ꢁ).
d
ꢁ63.0 (s, 3F, CF3), ꢁ130.3 (m, 2F,
F2,6),–140.8 (tt, 3J((F4, F3,5) = 20 Hz, 4J(F4, F2,6) = 7 Hz, 1F, F4),
ꢁ156.7 (m, 2F, F3,5), ꢁ145.3 (s, 4F, [BF4]ꢁ).
3.5.2. Preparation of [C6F5(C3F7CꢄC)Br][BF4] (11)
A 8-mm i.d. FEP trap equipped with a Teflon-coated magnetic
3.5.5. Reaction of C6F5BrF2 with C6F13BF2
stir bar was charged with
a
solution of C6F5BrF2 (57 mg,
A solution of C6F5BrF2 (60 mg, 0.21 mmol) in PFP (1.5 mL) was
cooled to ꢁ65 8C and a cold (ꢁ65 8C) solution of C6F13BF2
(0.45 mmol) in PFP (2 mL) was added in portions. The solution
was stirred at ꢁ60 8C for 1 h. The initially formed yellow
suspension became quickly (in 10–15 s) dark colored and after
20–30 min a colorless solution was formed. The 19F NMR spectrum
(ꢁ60 8C) showed resonances of C6F13BF2, C6F14, C6F5Br, and cyclo-
1-Br-1,4-C6F7 (45:20:23:12) besides PFP.
0.20 mmol) in PFP (0.7 mL) and cooled to ꢁ40 8C. Then a cold
(ꢁ40 8C) solution of C3F7CꢄCBF2 (0.22 mmol) in PFP (0.5 mL) was
added in portions. After stirring at ꢁ40 8C for 2 h the colorless
solution was evaporated to dryness in vacuum at 20 8C. The residue
was washed with CCl3F (1 mL) at 15 8C and the solid was dried in
vacuum at 20 8C to yield [C6F5(C3F7CꢄC)Br][BF4] (50 mg, 56%).
[C6F5(C3F7CꢄC)Br][BF4] (11). 11B NMR (aHF, 0 8C):
d
ꢁ2.1 (s,
[BF4]–). 13C{19F} NMR (aHF, 0 8C):
d 118.7 (C-5), 106.5 and 106.4 (C-
3 and C-4), 81.3 (C-2), 50.6 (C-1) (C3F7CꢄC moiety), 146.0 and
3.5.6. Reaction of C6F5BrF2 with C6F13CH2CH2BF2
145.7 (C4 and C2,6), 139.7 (C3,5), 101.0 (C1) (C6F5 moiety). 19F NMR
A solution of C6F5BrF2 (0.31 mmol) in PFP (1.9 mL) was cooled
(aHF, 0 8C):
d
ꢁ78.4 (t, 4J(F-5, F-3) = 9 Hz, 3F, F-5), ꢁ101.3 (tq, 3J(F-
to ꢁ63 8C and
a
cold (ꢁ62 8C) solution of C6F13CH2CH2BF2
3, F-4) = 4 Hz, 4J(F-3, F-5) = 9 Hz, 2F, F-3), ꢁ124.0 (t, 3J(F-4, F-
3) = 4 Hz, 2F, F-4) (C3F7CꢄC moiety), ꢁ127.1 (m, 2F, F2,6), ꢁ132.5
(tt, 3J(F4, F3,5) = 19 Hz, 4J(F4, F2,6) = 10 Hz, 1F, F4), ꢁ151.2 (m, 2F,
(0.31 mmol) in PFP (1.5 mL) was added in portions within
3 min. The initially formed yellow suspension became quickly
(in 20–30 s) dark colored and after 20–30 min a colorless solution
was formed. The reaction mixture was stirred at ꢁ60 8C for 1 h. The
19F NMR spectrum (ꢁ60 8C) showed resonances of
C6F13CH2CH2BF2, C6F13CH2CH2F, C6F5Br, cyclo-1-Br-1,4-C6F7,
cyclo-1-BrC6F9 and BF3 (36:11:33:6:4:10) besides PFP. The 11B
NMR spectrum (ꢁ60 8C) contained signals of C6F13CH2CH2BF2
(28.8 ppm) and BF3 (9.7 ppm) (1:1).
F3,5) (C6F5 moiety), ꢁ148.0 (s, 4F, [BF4]ꢁ). 19F NMR (PFP, ꢁ40 8C):
d
ꢁ79.0 (t, 4J(F-5, F-3) = 9 Hz, 3F, F-5), ꢁ101.9 (tq, 3J(F-3, F-4) = 4 Hz,
4J(F-3, F-5) = 9 Hz, 2F, F-3), -124.8 (t, 3J(F-4, F-3) = 4 Hz, 2F, F-4)
(C3F7CꢄC moiety), ꢁ127.6 (m, 2F, F2,6), ꢁ135.1 (tt, 3J(F4,
F3,5) = 19 Hz, 4J(F4, F2,6) = 9 Hz, 1F, F4), ꢁ152.6 (m, 2F, F3,5) (C6F5
moiety), ꢁ134.5 (s, 4F, [BF4]ꢁ).
0
3.5.3. Preparation of [C6F5(CF3CꢄC)Br][BF4] (23)
3.6. Reactions of [RF(RF )Br][BF4]
A 11.7-mm i.d. PFA trap equipped with a Teflon-coated
magnetic stir bar was charged with a solution of CF3CꢄCBF2ꢅNCCH3
ꢅNCCH3 (0.20 mmol) in CH3CN (1.5 mL) and cooled to ꢁ10 8C. Then
a cold (ꢁ10 8C) solution of C6F5BrF2 (0.19 mmol) in PFP (2.5 mL)
was added in portions. The yellow solution was stirred at ꢁ10 8C
for 30 min and warmed to 24 8C. The 19F NMR spectrum showed
3.6.1. Reaction of [C6F5(C3F7CꢄC)Br][BF4] (11) with aHF
A solution of salt 11 (50 mg) in aHF (0.6 mL) was kept at 22 8C in
a FEP inliner. After 12 h, the conversion of 11 was 38% and after
72 h the signals of 11 had disappeared (19F NMR) and new
resonances of C6F5Br, C3F7C(O)CH2F, [Z-C3F7CF55CH(C6F5)Br]+, and
[BF4]–(1:1:2:4) were now present. The solution was extracted with
cold (ꢁ20 8C) CCl3F (0.5 mL). The extract contained C6F5Br and
C3F7C(O)CH2F whereas the salt [C6F5(Z-C3F7CF55CH)Br][BF4]
remained in the acid phase.
signals of [C6F5(CF3CꢄC)Br][BF4] ( ꢁ50.2 (s, 3F, CF3), ꢁ129.9 (m,
d
2F, F2,6),–141.1 (tt, 3J(F4, F3,5) = 20 Hz, 4J(F4, F2,6) = 7 Hz, 1F, F4),
ꢁ156.4 (m, 2F, F3,5
)
(C6F5 moiety), ꢁ144.5 (s, 4F, [BF4]ꢁ),
CF3CꢄCBF2ꢅNCCH3, and C6F5Br in the ratio 1:3:4.
[C6F5(Z-C3F7CF55CH)Br][BF4] (25). 1H NMR (aHF, 24 8C):
d 7.94
3.5.4. Preparation of [C6F5(trans-CF3CF55CF)Br][trans-CF3CF55CFBF3]
(14)
(d, 3J(H1, F2) = 21 Hz, 1H, H1). 19F NMR (aHF, 24 8C):
d
ꢁ80.3 (t, 4J(F5,
F3) = 9 Hz, 3F, F5), ꢁ91.1 (m, 1F, F2), ꢁ117.6 (dq, 3J(F3, F2) = 13 Hz,
4J(F3, F5) = 9 Hz, 2F, F3), ꢁ125.8 (m, 2F, F4) (Z-C3F7CF55CH moiety),
ꢁ129.1 (m, 2F, F2,6), ꢁ136.3 (tt, 3J(F4, F3,5) = 20 Hz, 4J(F4,
F2,6) = 9 Hz, 1F, F4), ꢁ153.8 (m, 2F, F3,5) (C6F5 moiety), ꢁ151.0 (s,
4F, [BF4]ꢁ).
An 8-mm i.d. FEP trap equipped with a Teflon-coated magnetic
stir bar was charged with
a solution of C6F5BrF2 (45 mg,
0.15 mmol) in PFP (0.5 mL) and cooled to ꢁ40 8C. Then a cold
(ꢁ45 8C) solution of trans-CF3CF55CFBF2 (0.15 mmol) in PFP