NaBArЈ4 was prepared according to the literature.38 Penta-
fluoropyridine was obtained from Apollo Scientific Ltd. and
was dried over molecular sieves (4 Å). [Ni(COD)2] (Strem
Chemicals) was used as received. Complexes 1 and 3 were
prepared as described in the literature.6,8
with a solution of Et3Nؒ3HF in THF (0.60 mL, 0.60 mmol).
After stirring for 5 min at room temperature, the solvents
were removed under vacuum. The resulting yellow oil was
washed with hexane (3 mL). The resulting solid was then
recrystallised twice from hexane (3 mL) at Ϫ20 ЊC, providing
The NMR spectra were recorded with a Bruker AMX 500
yellow crystals of 6. Yield 61 mg (50%). IR (Nujol) ν/cmϪ1
:
1
spectrometer, except for the H{19F} decoupling experiments,
1617vw, 1584w, 1483vs, 1405vs, 1387w, 1250vw, 1230vw,
1090m, 1034m, 995s, 809m, 765w and 735vw (Found: C,
42.70; H, 6.48; N, 2.89. C17H31F6NNiP2 requires C, 42.18; H,
6.46; N, 2.89%).
which were carried out on a Bruker DRX 400 spectrometer.
The 1H NMR chemical shifts were referenced to residual
C6D5H at δ 7.15, or THF-d7 at δ 1.8. The 13C{1H} spectra
were referenced to C6D6 at δ 128.0 and THF at δ 26.7. The
19F NMR spectra were referenced either to internal C6F6 at
δ 162.9, or to external CFCl3 at δ 0. The 31P{1H} NMR spectra
were referenced externally to H3PO4 at δ 0. Mass spectra were
recorded on a VG Autospec (EI) or a Finnigan LCQ (electro-
spray) instrument. Infrared spectra were recorded on a
Mattson-Unicam RS spectrometer fitted with a CsI beam-
splitter. NMR data are listed in Table 1.
Synthesis of [NiCl{ꢀ-ꢁ2(C,N)-(2-C5NF4)}(PEt3)]2 (7). A solu-
tion of 2 (98 mg, 0.20 mmol) in diethyl ether (10 mL) was
treated with a solution of HBF4 in diethyl ether (39 µL, 0.24
mmol). After stirring for 1.5 h, the solvent was removed under
vacuum and the yellow residue was extracted with toluene
(5 mL). The extract was then filtered through a cannula and
the solvent pumped off. The resulting orange solid was washed
with hexane and dried in vacuo. Yield 51 mg (70%). IR (Nujol)
ν/cmϪ1: 1627s, 1593w, 1500vs, 1426s, 1300vw, 1271vw, 1262vw,
1164w, 1118s, 1110s, 1037s, 1015vs, 828s, 771m, 754m, 740s and
732m (Found: C, 36.95; H, 4.30; N, 3.16. C22H30Cl2F8N2Ni2P2
requires C, 36.46; H, 4.17; N, 3.87%).
Syntheses
Synthesis of trans-[NiCl(2-C5NF4)(PEt3)2] (2). (a) A solution
of 1 (473 mg, 1.02 mmol) in hexane (5 mL) was treated with a
solution of HCl in diethyl ether (1.02 mL, 1.02 mmol). After
stirring for 1 h, the solvent was removed under vacuum and the
yellow residue was extracted with hexane (5 mL). The extract
was then filtered through a cannula and the filtrate was concen-
trated to about 2 mL in vacuo. Orange crystals of 2 precipitated
at Ϫ20 ЊC. Yield 147 mg (30%). (b) A solution of 1 (223 mg,
0.48 mmol) in 5 mL of hexane was treated with Me3SiCl (60 µL,
0.48 mmol). After stirring for 1 h, the solvent was removed
under vacuum, and the yellow residue was extracted with hex-
ane (5 mL). The extract was then filtered through a cannula and
the filtrate was concentrated to about 2 mL in vacuo. Orange
crystals of 2 precipitated at Ϫ20 ЊC. Yield 180 mg (78%). (c)
[Ni(COD)2] (568 mg, 2.07 mmol) was suspended in 5 mL hex-
ane, and PEt3 (671 µL, 4.54 mmol) was added, giving a yellow
solution. After addition of C5F5N (249 µL, 2.27 mmol), the
reaction mixture was cooled to 0 ЊC and Me3SiCl (288 µL, 2.27
mmol) was added. The solution was stirred for 30 min at room
temperature and the volatiles were removed under vacuum. The
remaining yellow solid was dissolved in hexane (5 mL) and the
solution was filtered through a cannula. Orange crystals of 2
Synthesis of trans-[Ni(2-C5NF4)(NCMe)(PEt3)2]BF4 (8). A
solution of 1 (146 mg, 0.30 mmol) in acetonitrile (10 mL) was
treated with BF3ؒOEt2 (38 µL, 0.30 mmol). After stirring for
1 h, the solvent was removed under vacuum. The pale yellow
solid was washed with hexane and dried in vacuo. Yield 147 mg
(86%). IR (KBr) ν/cmϪ1: 2284vw, 1619w, 1484m, 1462w, 1404vs,
1384w, 1110vs, 1087vs, 1036vs, 991m, 917w, 806s, 761s and
726s. MS (ES): m/z 485 (Mϩ, 100), 444 ([M Ϫ MeCN]ϩ, 52), 367
([M Ϫ PEt3]ϩ, 7%) (Found: C, 39.85; H, 5.85; N, 4.68. C19H33-
BF8N2NiP2 requires C, 39.83; H, 5.81; N, 4.89%).
Synthesis of trans-[Ni(2-C5NF4)(NCMe)(PEt3)2]BArЈ4 (9). A
solution of 3 (300 mg, 0.50 mmol) in acetonitrile (20 mL) was
treated with NaBArЈ4 (448 mg, 0.50 mmol). After stirring for
1 h, the solvent was removed under vacuum and the yellow
residue was extracted with CH2Cl2 (5 mL). The extract was then
filtered through a cannula, the solvent was pumped off and the
yellow solid washed with hexane (10 mL). The residue was dis-
solved in CH2Cl2 (2 mL) and the solution was chromato-
graphed on silica (grade 12, 28–200 mesh, length of column 6
cm). A yellow fraction was eluted, from which the solvent was
removed in vacuo. The residue was washed with hexane (5 mL)
precipitated at Ϫ20 ЊC. Yield 794 mg (80%). IR (Nujol) ν/cmϪ1
:
1720vw, 1592vw, 1483s, 1465vs, 1408s, 1250vw, 1164w, 1090w,
1034m, 995m, 808w, 765s and 724vw (Found: C, 42.72; H,
6.77; N, 2.92. C17H30ClF4NNiP2 requires C, 42.49; H, 6.29;
N, 2.92%).
to give a yellow solid. Yield 675 mg (76%). IR (KBr) ν/cmϪ1
:
1619w, 1586w, 1489m, 1415m, 1354s, 1275vs, 1180m, 1160s,
1118vs, 1034m, 999m, 887m, 839s, 810w, 762m and
714s (Found: C, 45.76; H, 3.28; N, 2.00. C51H45BF28N2NiP2
requires C, 45.40; H, 3.36; N, 2.08%).
Synthesis of C5NF4H (4). A solution of 2 (56 mg, 0.17 mmol)
in 1.5 mL of C6D6 was treated with a solution of HCl in diethyl
ether (351 µL, 0.35 mmol). After 5 d the volatiles were
transferred under vacuum to an ampoule fitted with a Young’s
tap. The resulting colourless distillate was shown, using NMR
spectroscopy and GC, to contain C6D6 and 4 only. MS (EI): m/z
151 (Mϩ, 100), 132 ([M Ϫ F]ϩ, 19%).
Structure determination for complex 7
Orange crystals were obtained from a solution of 7 in toluene–
diethyl ether at Ϫ20 ЊC. Diffraction data were collected for a
block with dimensions 0.25 × 0.20 × 0.60 mm on a Rigaku
AFC6S diffractometer.
Formation of trans-[NiF(2-C5NF3H)(PEt3)2] (5). The distillate
containing 4 in C6D6 was treated with [Ni(COD)2] (30 mg, 0.11
mmol) and PEt3 (34 µL, 0.23 mmol). The resulting solution
contained mainly trans-[NiF(2-C5NF3H)(PEt3)2] (5), with the
compounds [Ni(PEt3)4] and trans-[NiCl(2-C5NF3H)(PEt3)2]
present as minor products. Complex 5 was converted into trans-
[NiCl(2-C5NF3H)(PEt3)2] by treatment with HCl. Selected
NMR data for trans-[NiCl(2-C5NF3H)(PEt3)2]: 1H NMR
(THF-d8): δ 8.44 (d, JHF = 7.5 Hz, CH). 31P NMR (THF-d8):
δ 14.2 (s). 19F NMR (THF-d8): Ϫ162.55 (d, br, JFF = 16.0, 1 F),
Ϫ158.56 (m, 1 F), Ϫ129.58 (d JFF = 27.8 Hz, 1 F).
Crystal data. C22H30Cl2F8N2Ni2P2, M = 724.74, monoclinic,
space group P21/a, a = 13.519(3), b = 14.205(7), c = 15.858(3) Å,
β = 101.188(2)Њ, U = 2987.4 Å3, T = 150 K, Z = 4, µ(Mo-
Kα) = 1.612 mmϪ1
,
5492/5251 measured/unique data,
Rint = 0.042. The structure was solved by direct methods (SIR-
92)39 and refined against F2 (SHELXL 93).40 H-atoms were
placed in idealised positions. Final R1, wR2 on all data 0.093,
0.1145. R1, wR2 on [Io > 2σ(Io)] data 0.0379, 0.0915.
CCDC reference number 186/1977.
Synthesis of trans-[Ni(FHF)(2-C5NF4)(PEt3)2] (6). A solu-
tion of 1 (115 mg, 0.25 mmol) in hexane (5 mL) was treated
lographic files in .cif format.
J. Chem. Soc., Dalton Trans., 2000, 2013–2018
2017
Archibald, Stephen J.
