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(5 mL). The mixture was stirred at room temperature for 2 h. It was
concentrated and stored at À408C for 12 h to yield dark brown
crystals of 2 (0.60 g, 70%). M.p.: 111–1138C; 1H NMR (400 MHz,
C6D6): d=4.40 (s, 4H, CHMe2), 1.60 (s, 12H, CMe), 1.30 (s, 24H,
CHMe2), 0.48 ppm (s, 36H, SiMe3); 13C NMR (101 MHz, [D8]THF): d=
207.7 (s, NCN), 122.2 (s, NC=), 49.1 (s, NMe), 24.8 (s, CHMe), 9.2 (s,
CHMe2), 5.9 ppm (s, SiMe3); elemental analysis: calcd for
C34H76YbN6Si4: C 47.80, H 8.97, N 9.84; found: C 47.76, H 8.99, N
9.81.
Typical procedure for the recycling and recovery of precata-
lyst 1
HPPh2 (2.5 mmol), an alkene (3 mmol), precatalyst 1 (0.125 mmol,
5 mmol%), and toluene (2 mL) were added to a round-bottomed
flask. The mixture was stirred under the required conditions. After
the catalytic reaction, precatalyst 1 was collected by filtration and
directly used for the next run. The recovery could be furnished in
50–74% yields by filtration and recrystallization from toluene.
Preparative-scale catalytic reactions
Synthesis of (IMe4)3Yb(PPh2)2 (3)
Diphenylphosphine (1 mmol), an alkene (1.2 mmol), precatalyst
1 (0.05 mmol, 5 mmol%), and toluene (1 mL) were added to
a round-bottomed flask. The mixture was stirred. After the reaction
was complete, the product was purified by chromatography on
silica gel (n-hexane/dichloromethane). Alternatively, H2O2 (30%,
1 mL) was added to the mixture and it was stirred for 3 h to yield
the corresponding oxidation product. The product was extracted
with CH2Cl2 and dried over MgSO4. After the solvent was removed,
the crude product was purified by chromatography on silica gel (n-
hexane/ethyl acetate).
Method A: (IMe4)2Yb[N(SiMe3)2]2 (1; 0.37 g, 0.5 mmol) was added to
a solution of Ph2PH (0.19 g, 1.0 mmol) in toluene (10 mL). The mix-
ture was stirred at room temperature for 12 h. It was concentrated
and stored at À408C for 12 h to yield dark green crystals of 3
(0.19 g, 41%).
Method B: (THF)4Yb(PPh2)2 (0.41 g, 0.5 mmol) was added to a solu-
tion of IMe4 (0.19 g, 1.5 mmol) in toluene (10 mL). The mixture was
stirred at room temperature for 3 h. It was concentrated and
stored at À408C for 12 h to yield dark green crystals of 3 (0.29 g,
64%).
M.p.: 170–1738C; 1H NMR (400 MHz, C6D6): d=7.60 (s, 8H, Ar),
6.79–6.95 (m, 12H, Ar), 3.43 (s, 18H, NCH3), 1.41 ppm (s, 18H, CH3);
13C NMR (101 MHz, C6D6): d=201.3 (s, NCN), 153.0 (d, JCÀP =39.0 Hz,
Ar), 131.4 (d, JCÀP =15.6 Hz, Ar), 127.1 (d, JCÀP =5.4 Hz, Ar), 123.7 (s,
Ar), 120.5 (s, NC=), 34.3 (s, NMe), 8.2 ppm (s, CMe); 31P NMR
(162 MHz, C6D6, 258C): d=10.7 (br); 31P NMR (162 MHz, [D8]toluene,
808C): d=12.8 (s); elemental analysis: calcd for C45H56YbN6P2: C
59.01, H 6.16, N 9.18; found: C 58.92, H 6.18, N 9.21.
X-ray crystal structure determination
X-ray data were collected on a Rigaku Saturn CCD diffractometer
by using graphite-monochromated Mo Ka radiation (l=0.71073 )
at 113 K. The structure was solved by direct methods (SHELXS-
97)[17] and refined by full-matrix least squares on F2. All non-hydro-
gen atoms were refined anisotropically and hydrogen atoms were
refined with a riding model (SHELXL-97).[18] The crystal data and
structure-refinement details are listed in Table S1 in the Supporting
Information. CCDC 1406410 (1) and 1406411 (3) contain the supple-
mentary crystallographic data for this paper. These data are provid-
NMR-scale catalytic reactions
In a glovebox, HPPh2 (0.25 mmol), C6D6 (0.4 mL), and an alkene or
alkyne (0.3 mmol) were placed in a Young’s tap NMR tube. This
was followed by addition of precatalyst 1 (0.0125 mmol, 5 mol%)
under the conditions given in Table 2. The conversions of HPPh2
were determined by 1H and 31P NMR spectroscopy.
Spectroscopic data for the hydrophosphination products
Phenethyldiphenylphosphine:[19] 1H NMR (400 MHz, CDCl3): d=
7.35–7.40 (m, 4H, Ar), 7.09–7.29 (m, 11 H, Ar), 2.62–2.68 (m, 2H,
PhCH2), 2.27–2.31 ppm (m, 2H, CH2PPh2); 31P NMR (162 MHz,
CDCl3): d=À15.9 ppm (s).
Polymerization reaction
(4-Methylphenethyl)diphenylphosphine:[8j] 1H NMR (400 MHz,
C6D6): d=6.96–7.41 (m, 14H, Ar), 2.68 (br, 2H, ArCH2), 2.25 (br, 2H,
CH2PPh2), 2.12 ppm (s, 3H, CH3); 31P NMR (162 MHz, C6D6): d=
À16.2 ppm (s).
In a glovebox, alkene (10 mmol), solvent (1 mL), and catalyst 3
(0.005–0.02 mmol) were added into a 10 mL flask. A dark brown
mixture was obtained and the polymerization was initiated and
carried out for the required temperature and time. The reaction
mixture was poured into MeOH (30 mL) to precipitate the polymer
product, then 30% H2O2 (0.5 mL) was added and the reaction mix-
ture was stirred at room temperature for 1 h. The white polymer
product was collected by filtration and dried under vacuum at
608C until a constant weight was achieved.
1
(4-Methylphenethyl)diphenylphosphine oxide: H NMR (400 MHz,
CDCl3): d=7.74–7.79 (m, 4H, Ar), 7.48–7.55 (m, 6H, Ar), 7.06 (s, 4H,
Ar), 2.86–2.92 (m, 2H, ArCH2), 2.53–2.60 (m, 2H, CH2PPh2), 2.30 ppm
(s, 3H, CH3); 31P NMR (162 MHz, CDCl3): d=31.7 ppm (s).
(4-Methoxyphenethyl)diphenylphosphine:[19] 1H NMR (400 MHz,
CDCl3): d=7.32–7.53 (m, 10H, Ar), 7.08 (d, J=8.3 Hz, 2H, Ar), 6.81
(d, J=8.4 Hz, 2H, Ar), 3.77 (s, 3H, OCH3), 2.63–2.69 (m, 2H, ArCH2),
2.31–2.35 ppm (m, 2H, CH2PPh2); 31P NMR (162 MHz, CDCl3): d=
À16.2 ppm (s).
Phosphine-terminated atactic polystyrene: 1H NMR (400 MHz,
CDCl3): d=7.14 (br, Ar), 6.65 (br, Ar), 1.92–2.28 (m, PhCH), 1.51 ppm
(br, CH2); 31P NMR (162 MHz, CDCl3): d=31.5 ppm (s).
Phosphine-terminated atactic poly(1-chloro-4-vinylbenzene):
1H NMR (400 MHz, CDCl3): d=7.05 (br, Ar), 6.40 (br, Ar), 1.81–2.06
(m, PhCH), 1.33 ppm (br, CH2); 31P NMR (162 MHz, CDCl3): d=
29.2 ppm (s).
(4-Fluorophenethyl)diphenylphosphine:[20] 1H NMR (400 MHz,
CDCl3): d=7.26–7.38 (m, 10H, Ar), 7.02–7.05 (m, 2H, Ar), 6.87 (t, J=
8.4 Hz, 2H, Ar), 2.58–2.65 (m, 2H, ArCH2), 2.24–2.28 ppm (m, 2H,
CH2PPh2); 31P NMR (162 MHz, CDCl3): d=À16.3 ppm (s).
Phosphine-terminated atactic poly(1-methoxy-4-vinylbenzene):
1H NMR (400 MHz, CDCl3): d=7.35 (br, Ar), 6.57 (br, Ar), 3.73 (br,
OMe), 1.73–2.17 (m, PhCH), 1.34 ppm (br, CH2); 31P NMR (162 MHz,
CDCl3): d=31.6 ppm (s).
(4-Chlorophenethyl)diphenylphosphine:[21] 1H NMR (400 MHz,
CDCl3): d=7.25–7.44 (m, 10H, Ar), 7.14–7.17 (m, 2H, Ar), 7.01 (d,
J=8.4 Hz, 2H, Ar), 2.58–2.64 (m, 2H, ArCH2), 2.23–2.27 ppm (m, 2H,
CH2PPh2); 31P NMR (162 MHz, CDCl3): d=À16.3 ppm (s).
Chem. Eur. J. 2016, 22, 5778 – 5785
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