A. Abo-Amer et al. / Journal of Fluorine Chemistry 125 (2004) 1771–1778
19
1777
5
6
4
(
(
(
2F, m, F ), ꢀ121.4 (2F, m, F ). ꢀ122.1 (2F, m, F ), ꢀ124.8
F NMR (ether, 24 8C), d: ꢀ82.5 (3F, s, br, CF ), ꢀ125.6
3
7
1
11
(2F, q(unresolved), CF ); B NMR (ether, 24 8C), d: ꢀ2.1
2F, m, F , ꢀ141.5 (3F, br, t = 144 Hz, BF ); H NMR
1
/2
3
2
1
2
11
2
(quin, J(B, F ) = 15 Hz).
1
CD NO , 24 8C), d: 2.0 (2H, m, H ), 0.3 (2H, m, H );
B
3
2
NMR (CD NO , 24 8C), d: 7.9 (s, br, t = 211 Hz, BF3);
3
2
1/2
1
1
B NMR (acetone-d , 24 8C), d: 5.0 (s, br, t = 200 Hz,
4.3.2. Preparation of K[(C F ) BF ]
2
6
1/2
5 2
2
BF3).
.2.2. Preparation of C F C H BF
2
K[(C F ) B(OMe) ] was treated with 52% HF (40 ml)
2 5 2 2 aq
at 20 8C for 4 days. The solution was neutralised with KOH
and saturated with KF before being extracted with ether.
After removal of the ether an oily product (2.73 g) remained
which was stirred with 7 ml aHF in a plugged FEP trap at
20 8C for 24 h. HF and volatile by-products were removed
under reduced pressure and the solid residue was dissolved
in 10 ml water and treated with charcoal (0.5 g). After
filtration the residue was washed with water (10 ml) and the
combined aqueous phases which showed an acidic reaction
were neutralised with KOH and saturated with KF and
finally extracted with ether (five times 10 ml). After
removing of ether 2.59 g (7.95 mmol, 56.8%) of solid
K[(C F ) BF ] were isolated. K[(C F ) BF ] is soluble in
4
6
13
2
4
K[C F C H BF ] (177 mg, 0.39 mmol) was suspended
6
13
2
4
3
in CH Cl (0.7 ml) at ꢀ50 8C in a FEP trap. BF gas
2
2
3
(
8.3 mmol) was supplied under intensive stirring within
5 min. The appearance of the solid changed during the
2
treatment with BF . After 1 h of stirring at 20 8C the excess
3
of BF was removed at ꢀ78 8C three times in static and once
3
in dynamic vacuum. The mother liquor was separated after
centrifugation. The solid residue was extracted three times
with 0.5 ml of CH Cl . The content of C F C H BF in the
2
2
6
13
2
4
2
combined CH Cl phase was determined with C H CF as
2
2
1
6
5
3
9
internal standard ( F NMR): 0.20 mmol (52%). Removal of
the solvent at ca. ꢀ50 8C in vacuum was connected with a
larger loss of product. The boiling point of C F C H BF
2
5 2
2
2
5 2
2
H O, MeOH, Et O, and MeCN.
2
2
Purification of K[(C F ) BF ] proceeded by dissolution
2
6
13
2
4
2
5 2
2
ꢀ
2
was determined to 24 8C/2 Â 10 hPa.
in water and treatment with charcoal. Water was distilled off
from the aqueous filtrate and the white solid residue was
dried in a vacuum desiccator over P O for 2 days.
1
9
F NMR (CH Cl , 24 8C), d: ꢀ73.8 (2F, s, br, t
=
2
2
1/2
5
4
8
6
5
8
2
18 Hz, BF ), ꢀ81.6 (3F, tt, J(F , F ) = 10 Hz, J(F , F ) =
2
4 10
8
3
5
19
3
2
1
3
Hz, F ), ꢀ116.6 (2F, m, F , ꢀ122.5 (2F, m, F ), ꢀ123.5
F NMR (ether, 24 8C), d: ꢀ82.9 (6F, tm, J(F , F ) =
6
4
7
1
(
(
(
2F, m, F ), ꢀ124.2 (2F, m, F ), ꢀ126.8 (2F, m, F ); H NMR
6 Hz, CF ), ꢀ134.8 (4F, m (unresolved), CF ), ꢀ175.0 (2F,
3
2
1
2
11
1
11
11
CH Cl , 24 8C), d: 1.5 (2H, m, H ), 0.5 (2H, m, H );
B
m, J(BF, B) = 64 Hz, BF ); B (ether, 24 8C), d: 0.1
2 2
2
1 2 1 13
CH Cl , 24 8C), d: 27.5 (s, br, t = 210 Hz, BF2).
(tquin, J(B, F) = 64 Hz, J(B, F ) = 22 Hz; C (D O,
2
2
2
1/2
1
2
2
2
2
1
2
4 8C), d: 122.6 (qt, J(C , F ) = 285 Hz, J(C , F ) = 32 Hz,
2
1
4
.3. The synthesis of potassium
C ), 120.5 (s, br, t = 440 Hz, C ).
1/2
bis(pentafluoroethyl)dimethoxyborate and potassium
bis(pentafluoroethyl)difluoroborate
4.4. The introduction of the 2,3,5,6-tetrafluoropyrid-4-yl
group into the hypervalent IF triad of
pentafluorophenyliodinedifluoride
2
4
.3.1. Preparation of K[(C F ) B(OMe) ]
2
2
5 2
A three-necked flask with a dry Ar-atmosphere equipped
with an internal thermometer, and a magnetic stirring bar
was charged with ether (120 ml) at ꢀ95 to ꢀ90 8C (acetone
bath cooled with liquid N ) before C F I (24 g, 38 mmol)
4.4.1. Pentafluorophenyl(2,3,5,6-tetrafluoropyrid-4-
yl)iodonium tetrafluoroborate
A solution of (4-C F N)BF (43 mg, 0.22 mmol) in
2
2
5
5
4
2
was condensed. A MeLi solution in ether (20 ml, 1.6 m,
2 mmol) was added using a syringe within 15 min and
CH Cl (0 8C, 20 ml) was added within 1 h to a CH Cl
2
2
2
2
3
solution (0 8C, 2 ml) of C F IF (107 mg, 0.32 mmol).
6
5
2
keeping the temperature below ꢀ90 8C. After 30 min a
Spontaneously a greenish solid was formed. After 1.5 h of
stirring at 0 8C the mother liquor was separated and the solid
residue was washed with CH Cl (0 8C, 5 ml) and dried in
BCl(OMe) solution in hexane (1.5 g, 14 mmol, in 3.5 ml)
2
was added in one portion to the white suspension using a
syringe. The internal temperature increased up to a
maximum of ꢀ85 8C. After 40 min at <ꢀ90 8C the bath
was warmed to ꢀ78 8C for 3 h. Following the solution was
warmed to 20 8C within 1 h and formed a suspension. KF
2
2
vacuum and finally at 20 8C for 0.5 h. During this procedure
the colour of the solid became white. The dissolution of the
1
solid product in MeCN revealed a mixture ( F NMR).
9
1
9
+
F NMR (MeCN, 24 8C), d: [C F (4-C F N)I] ꢀ84.3
6
5
5 4
(
8 g, 138 mmol) and H O (20 ml) were added and stirring
(2F, m, F-2, 6, (4-C F N)), ꢀ119.7 (2F, m, F-2, 6, C F ),
5 4
2
5
4
6 5
3
was continued for a further hour. The ether mother liquor
was separated, the residue extracted with ether (three times
ꢀ123.1 (2F, m, F-3, 5, (4-C F N)), ꢀ140.6 (1F, tt, J(F-4, F-
4
3, 5) = 20 Hz, J(F-4, F-2, 6) = 7 Hz, F-4, C F ), ꢀ155.1 (2F,
6 5
ꢀ
3
1
0 ml), the ether phases were combined and finally ether was
removed under reduced pressure. A crystalline product
3.37 g, 69% yield of K[(C F ) B(OMe) ]) remained which
m, F-3, 5, C F ), [(4-C F N)BF ] ꢀ97.3 (2F, m, F-2, 6),
6
5
1
5
11
4
4
ꢀ134.2 (3F, qt, J(BF, B) = 42 Hz, J(BF, F-2, 6) = 12 Hz,
ꢀ
(
BF), ꢀ137.3 (2F, m, F-3, 5), [BF ] ꢀ148.5 (s, br, BF),
2
5 2
2
4
3
was soluble in water and MeOH.
C H BF KO (350.00): calculated (%): C 20.59, H 1.73;
found (%) C 20.02, H 1.55.
C F I ꢀ120.1 (2F, m, F-2, 6, C F ), ꢀ153.4 (1F, t, J(F-4, F-
6
5
6 5
3, 5) = 19 Hz, F-4, C F ), ꢀ160.1 (2F, m, F-3, 5, C F );
6
6
10
2
6
5
6 5
molar ratio 98:21:77:2.