Rh(pph3)3cl/tetrakis(dialkylamino)phosphonium salts as thermoregulated and recyclable catalytic system for hydrosilylation reaction

Article abstract of DOI:10.1080/10426507.2011.561458

Eleven tetrakis(dialkylamino)phosphonium salts have been prepared and were used as "soft" catalyst supports for the hydrosilylation reaction of styrene with triethoxysilane catalyzed by Rh(PPh₃)₃Cl. Among the Rh(PPh₃)₃Cl/tetrakis(dialkylamino)phosphonium salts tested, the best catalytic activity and selectivity in favor of the β-adduct were obtained when {[(C₄H₉) ₂N]₃[(C₈H₁₇)₂N]P}PF ₆ was used as the support, and Rh(PPh₃)₃Cl/ {[(C₄H₉)₂N]₃[(C₈H ₁₇)₂N]P}PF₆ catalyst system can be reused more than 10 times without noticeable loss of catalytic activity and selectivity. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/10426507.2011.561458

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Phosphorus, Sulfur, and Silicon and the
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Rh(PPh3)3Cl/
Tetrakis(Dialkylamino)Phosphonium Salts
as Thermoregulated and Recyclable
Catalytic System for Hydrosilylation
Reaction
Diliang Wang a , Jiayun Li a , Jiajian Peng a , Ying Bai a & Guoqiao Lai
a
a Key Laboratory of Organosilicon Chemistry and Material Technology
of Ministry of Education , Hangzhou Normal University , Hangzhou,
People's Republic of China
Published online: 31 Oct 2011.
To cite this article: Diliang Wang , Jiayun Li , Jiajian Peng , Ying Bai & Guoqiao Lai (2011)
Rh(PPh3)3Cl/Tetrakis(Dialkylamino)Phosphonium Salts as Thermoregulated and Recyclable Catalytic
System for Hydrosilylation Reaction, Phosphorus, Sulfur, and Silicon and the Related Elements, 186:11,
2258-2266, DOI: 10.1080/10426507.2011.561458
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Phosphorus, Sulfur, and Silicon, 186:2258–2266, 2011
Copyright ꢀC Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426507.2011.561458
Rh(PPh3)3Cl/TETRAKIS(DIALKYLAMINO)PHOSPHONIUM
SALTS AS THERMOREGULATED AND RECYCLABLE
CATALYTIC SYSTEM FOR HYDROSILYLATION REACTION
Diliang Wang, Jiayun Li, Jiajian Peng, Ying Bai,
and Guoqiao Lai
Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry
of Education, Hangzhou Normal University, Hangzhou, People’s Republic of China
GRAPHICAL ABSTRACT
Si(OEt)3
α-adduct
Si(OEt)3
β-adduct
Rh catalyst
+
HSi(OEt)3
hydrogenation product
Si(OEt)3
dehydrogenative silylation product
Abstract Eleven tetrakis(dialkylamino)phosphonium salts have been prepared and were
used as “soft” catalyst supports for the hydrosilylation reaction of styrene with triethoxysi-
lane catalyzed by Rh(PPh3)3Cl. Among the Rh(PPh3)3Cl/tetrakis(dialkylamino)phosphonium
salts tested, the best catalytic activity and selectivity in favor of the β-adduct were ob-
tained when {[(C4H9)2N]3[(C8H17)2N]P}PF6 was used as the support, and Rh(PPh3)3Cl/
{[(C4H9)2N]3[(C8H17)2N]P}PF6 catalyst system can be reused more than 10 times without
noticeable loss of catalytic activity and selectivity.
Keywords Tetrakis(dialkylamino)phosphonium salts; hydrosilylation; Rh(PPh3)3Cl
INTRODUCTION
Hydrosilylation is one of the most important reactions for Si-C bond formation in
organosilicon chemistry. Transition metal complexes have usually been applied as catalysts
Received 8 December 2010; accepted 5 February 2011.
Address correspondence to Jiayun Li, Key Laboratory of Organosilicon Chemistry and Material Technology
of Ministry of Education, Hangzhou Normal University, Hangzhou 310012, People’s Republic of China. E-mail:
jiayun1980@hznu.edu.cn
2258

Rh(PPh3)3Cl/TETRAKIS(DIALKYLAMINO)PHOSPHONIUM SALTS
2259
for hydrosilylation reactions.1–3 However, the types of hydrosilylation catalyst available
are not beneficial for product separation and are expensive.4,5 In view of the economic
and ecological point, intensive research has been done on both the improvement of cat-
alyst and the reuse of the expensive precious metal catalyst in homogenous catalytic
process. Very recently, Weyershausen et al.,6 reported that catalytic activities of platinum
complexes for hydrosilylation reactions were remarkably improved by using ionic liq-
uids as media. Independently, hydrosilylation reactions catalyzed with Rh(PPh3)3Cl in
ionic liquids were studied in our laboratory.7,8 It was observed that both conversion and
selectivity could be influenced by the alkyl chains attached to the pyridinium and imi-
dazolium cations. The Rh(PPh3)3Cl/ionic liquid (molten salt) catalyst system combines
the advantages of an ionic liquid with convenient product separation, while the catalyst
system can be reused at least 10 times without noticeable decrease of activity and selectiv-
ity. tetrakis(dialkylamino)phosphonium salts are novel phase-transfer catalysts that were
mostly used in fluorination of aromatic compounds and Halex reaction. During the pro-
cess they showed several advantages including excellent catalytic capabilities, low toxicity,
perfect thermal stability and recyclability.9–11 Similar to room temperature ionic liquids,
there is also no limit to the number of tetrakis(dialkylamino)phosphonium salts that can
be made, and the suitable properties for specific chemical reactions and processes can be
“designed” by changing the kinds of quaternary phosphonium cations as well as the type
of anions present. In this paper, N-alkyl quanternary phosphonium salts are synthesized
and used as novel “soft” support for the immobilization of transition metal complexes
as catalysts for hydrosilylation reaction. N-alkyl quanternary phosphonium salts includ-
ing [(Et2N)3(R2N)P]PF6, {[(C4H9)2N]3(R2N)P}PF6, and [(Piperdino)3(R2N)P]PF6 (R =
ethyl, butyl, hexyl, octyl), were synthesized; and the influence of the structure of N-alkyl
quanternary phosphonium salts on hydrosilylation reactions has also been investigated.
Scheme 1
RESULTS AND DISCUSSION
In previous reports,7 we have found that organic molten N-alkylpyridinium or N,
N-dialkylimidazolium salts, which are solid at room temperature, can be used as “soft”
support for transition metal catalysts, and the transition metal complexes/N-alkylpyridinium
or N, N-dialkylimidazolium salts are recyclable catalyst system for hydrosilylation of

2260
D. WANG ET AL.
Table 1 The hydrosilylation reaction of styrene with triethoxysilane
Selectivity
Entry
Support
Conversion
β
α
Ax
By
β/α
a
1
2
3
4
5
6
7
8
9
10b
11c
12d
13e
14
15
16
17
C4H9PyPF6
98.6
78.1
100
100
100
100
100
100
100
100
91.1
100
100
100
100
100
100
88.7
81.2
81.5
84.8
86.9
89.8
91.8
92.8
93.8
93.1
94.5
93.7
94.0
75.4
80.2
81.7
84.1
4.1
16.5
8.2
7.0
6.6
5.5
3.5
3.1
2.4
2.8
1.7
2.4
2.2
11.4
9.2
8.6
8.4
–
–
7.2
2.3
9.5
7.7
6.4
4.7
4.7
4.1
3.8
4.1
3.8
3.9
3.8
6.5
5.2
5.0
3.9
21.6
4.9
a
CH3(C4H9)ImPF6
{[N(C2H5)2]4P}PF6
0.8
0.5
0.1
∼0
∼0
∼0
∼0
∼0
∼0
∼0
∼0
6.7
5.4
4.7
3.6
10.3
12.1
13.2
16.3
26.2
29.9
39.1
33.3
55.6
39.0
42.7
6.6
{[N(C2H5)2]3[N(C4H9)2]P}PF6
{[N(C2H5)2]3[N(C6H13)2]P}PF6
{[N(C2H5)2]3[N(C8H17)2]P}PF6
[N(C4H9)2]4P]PF6
{[N(C4H9)2]3[N(C6H13)2]P}PF6
{[N(C4H9)2]3[N(C8H17)2]P}PF6
{[N(C4H9)2]3[N(C8H17)2]P}PF6
{[N(C4H9)2]3[N(C8H17)2]P}PF6
{[N(C4H9)2]3[N(C8H17)2]P}PF6
{[N(C4H9)2]3[N(C8H17)2]P}PF6
{[N(C5H10)]3[N(C2H5)2]P}PF6
{[N(C5H10)]3[N(C4H9)2]P}PF6
{[N(C5H10)]3[N(C6H13)2]P}PF6
{[N(C5H10)]3[N(C8H17)2]P}PF6
8.7
9.5
10.0
Reaction conditions: styrene 2.5 mmol; triethoxysilane 3.0 mmol; 95 ◦C, 2 h.
Rhodium complex: 0.05 mol% based on styrene, support 0.2 g.
aRhodium complex 0.1 mol% based on styrene, support 0.4 g.
bRhodium complex 0.1 mol% based on styrene, support 0.2 g.
cRhodium complex 0.03 mol% based on styrene, support 0.2 g.
dRhodium complex 0.05 mol% based on styrene, support 0.4 g.
eRhodium complex 0.05 mol% based on styrene, support 0.1 g.
xA was dehydrogenative silylation product.
yB was hydrogenation product.
alkenes and triethoxysilane. In this process, the catalyst is liquid phase under the reaction
conditions, whereas it is solid phase before and after the reaction. Herein, the use of
Rh(PPh3)3Cl/tetrakis(dialkylamino)phosphonium salts as a thermoregulated and recyclable
catalytic system for hydrosilylation was investigated. The results listed in Table 1 indicate
that catalytic activity and selectivity of Rh(PPh3)3Cl for hydrosilylation of styrene and
triethoxysilane were almost improved by using tetrakis(dialkylamino)phosphonium salts as
“soft” support in comparing with N-alkylpyridinium salt. When complex Rh(PPh3)3Cl was
mixed with [(Piperdino)3(R2N)P]PF6, it showed low selectivity of the β-adduct and some
dehydrogenative silylation product was obtained. When complex Rh(PPh3)3Cl was mixed
with [(Et2N)3(R2N)P]PF6, high selectivity of the β-adduct was obtained, and minimum
dehydrogenative silylation product was detected. Especially, {[(C4H9)2N]3(R2N)P}PF6,
was used as support, higher selectivity of the β-adduct was obtained. In this case, we also
observed that the selectivity of the β-adduct was increased with lengthening of the alkyl
chain attached to the quaternary phosphonium cation. This demonstrated that the attached
cationic substituents had a significant impact on the catalytic process, especially on the
selectivity. On the basis of the screening of tetrakis(dialkylamino)phosphonium salts, it
was concluded that the best catalytic activity and selectivity in favor of the β-adduct were
obtained when {[N(C4H9)2]3[N(C8H17)2]P}PF6 was used as the support. On the basis
of these date, we propose the reaction mechanism shown in Scheme 2. In the reaction

Rh(PPh3)3Cl/TETRAKIS(DIALKYLAMINO)PHOSPHONIUM SALTS
2261
Scheme 2
mechanism, we observed that the steric of cation A was increased with lengthening of the
alkyl chain attached to the quaternary phosphonium, which is conducive to the occurrence
of the β-adduct (Scheme 2). So, the selectivity in favor of the β-adduct was obtained.
The hydrosilylation reactions were examined in the presence of 0.1, 0.05, and 0.03
mol% of Rh(PPh3)3Cl, respectively. The conversions of styrene were 100, 100, and 91.1%,
Table 2 Catalyst recycling of the hydrosilylation reaction of styrene with triethoxysilane
Selectivity
Catalyst runs
Conversion
β
α
Ax
By
1
2
3
4
5
6
7
8
9
100
100
100
100
100
100
100
99.9
99.1
98.3
93.8
93.9
93.9
93.8
94.0
93.9
93.6
93.8
93.9
94.1
2.4
2.4
2.3
2.5
2.4
2.4
2.6
2.3
2.3
2.3
∼0
∼0
∼0
∼0
∼0
∼0
∼0
∼0
∼0
∼0
3.8
3.7
3.8
3.7
3.6
3.7
3.8
3.9
3.8
3.6
10
Reaction conditions: styrene 2.5 mmol; triethoxysilane 3.0 mmol; 95 ◦C, 2 h. Rhodium complex: 0.05 mol%
based on styrene, support: {[N(C4H9)2]3[N(C8H17)2]P}PF6: 0.2 g.
xA was dehydrogenative silylation product.
yB was hydrogenation product.

2262
D. WANG ET AL.
Table 3 The hydrosilylation reaction of aliphatic alkenes with triethoxysilane
Selectivity
Entry
Alkene
1-Hexene
Silane
Conversion
β
α
Aa
Bb
1
2
3
4
5
6
7
8
100
100
100
100
100
100
100
100
100
100
100
∼0
∼0
∼0
∼0
7.8
5.3
2.9
2.2
∼0
∼0
∼0
∼0
∼0
∼0
∼0
5.4
∼0
∼0
∼0
∼0
3.1
3.4
2.9
3.6
1-Dodecene
1-Hexadecene
1-Tetradecene
4-Methoxystyrene
4-Methylstyrene
4-Chlorostyrene
Styrene
Triethoxysilane
Triethylsilane
100
89.1
91.3
94.2
88.8
Reaction conditions: Alkene 2.5 mmol; Silane 3.0 mmol; 95 ◦C, 2 h.
Rhodium complex: 0.05 mol% based on styrene, support: {[N(C4H9)2]3[N(C8H17)2]P}PF6 0.2 g.
aA was dehydrogenative silylation product.
bB was hydrogenation product.
respectively, and the selectivities of the β-product were 93.1, 93.8, and 94.5, respec-
tively (Table 1). Although the conversion of styrene increased with increasing amount
of Rh(PPh3)3Cl used, the selectivities of the β-adduct deceased slightly. Meanwhile, the
amount of {[N(C4H9)2]3[N(C8H17)2]P}PF6 used had no effect on the conversion of styrene
and selectivity of the β-adduct.
Rh(PPh3)3Cl/tetrakis(dialkylamino)phosphonium salts become liquid under reaction
conditions. For each test cycle, products were decanted, leaving the catalyst on the bottom
of the reaction vessel. In general, Rh(PPh3)3Cl/tetrakis(dialkylamino)phosphonium salts
show excellent stability for the hydrosilylation reaction of styrene and triethoxysilane. For
example, Rh(PPh3)3Cl/{[N(C4H9)2]3[N(C8H17)2]P}PF6 catalysts can be reused more than
10 times without noticeable loss of catalytic activity and selectivity. The results of catalyst
recycling measurements are listed in Table 2.
When other alkenes, such as 1-hexene, 1-dodecene, 1-hexadecene, 1-tetradecene,
4-methoxy-styrene, 4-methyl-styrene, or 4-chlorostyrene were used in place of styrene as
the substrate, excellent conversions and selectivities were obtained with the Rh(PPh3)3Cl/
{[N(C4H9)2]3[N(C8H17)2]P}PF6 catalyst system (Table 3). Also, when triethylsilane re-
placed triethoxysilane as one of the substrates, unsaturated adduct triethyl(styryl)silane
was obtained, because triethylsilane is easier to dehydrogenate than triethoxysilane.
CONCLUSION
In summary, Rh(PPh3)3Cl/tetrakis(dialkylamino)phosphonium salts become liquid
under reaction conditions. Rh(PPh3)3Cl/tetrakis(dialkylamino)phosphonium salts show
excellent stability for the hydrosilylation reaction of styrene and triethoxysilane. Based
on the screening of tetrakis(dialkylamino)phosphonium salts, it was concluded that the
best catalytic activity and selectivity in favor of the β-adduct were obtained when
{[N(C4H9)2]3[N(C8H17)2]P}PF6 was used as the support. Rh(PPh3)3Cl/{[N(C4H9)2]3
[N(C8H17)2]P}PF6 catalysts can be reused more than 10 times without noticeable loss
of catalytic activity and selectivity.

Rh(PPh3)3Cl/TETRAKIS(DIALKYLAMINO)PHOSPHONIUM SALTS
2263
EXPERIMENTAL
General Methods
Tetrahydrofuran (THF) was distilled from benzophenone over sodium wire. Styrene
was washed with 5% NaOH and dried with Na2SO4. After filtration, the styrene was distilled
under reduced pressure. All other substances were purchased from Aldrich and were used
as received. Rh(PPh3)3Cl was prepared according to a procedure from the literature.12
GC/MS: Trace DSQ GC/MS column: DB-5 30 m × 25 mm × 0.25 m; split: 50:1;
flow: 1 mL/min constant flow; inlet temperature: 260 ◦C; column temperature: 50 ◦C (hold
1 min) then 15 ◦C/min up to 260 ◦C (hold 10 min).
1H, 13C, and 31P NMR spectra were measured using a Bruker AV400 MHz spectrom-
eter operating at 400.13, 100.62, and 161.97 MHz, respectively. Chemical shifts for 1H and
13C spectra were recorded in ppm relative to residual proton of CDCl3 (1H: δ 7.24; 13C δ
77.0) and DMSO-d6 (1H: δ 2.50; 13C δ 39.5). 31P NMR chemical shifts are relative to 85%
H3PO4 external standard.
Synthesis of Tetrakis(Dialkylamino)Phosphonium Salts
PCl5 (6.24 g, 0.03 mol) in dried CH2Cl2 (45 mL) was stirred under a nitrogen
◦
atmosphere. After cooling the mixture to −20 C, diethylamine (0.09 mol) was added.
Then triethylamine (12.14 g, 0.12 mol) was added to neutralize the acid in the mixture. The
reaction mixture was then stirred at room temperature for 2 h.
◦
Upon completion of the reaction, the solution was cooled to 0 C and anhydrous
ammonia was passed into the mixture. After it was stirred at room temperature for 2 h, the
precipitated solid was removed by filtration.
The solvent and other volatile components were completely removed under vacuum.
The residue was dissolved in water (8 mL) and sodium hydroxide solution (40%, 12 g)
was added, and stirred at room temperature for 1 h. Upon distillation, a mixture of NH3,
Et2NH, H2O was removed. Then, sodium hydroxide solution (40%, 12 g) was added. The
mixture was extracted with toluene. The organic layer was separated. After the toluene was
removed under vacuum, the product was obtained.
To the product in CH2Cl2 (45 mL) cooled with an ice bath was added dropwise
dibromoethane (9.8 g, 0.09 mol◦). Then, sodium hydroxide solution (50%, 20 g) was added.
The mixture was stirred at 60 C for 4 h. Upon completion of the reaction, the reaction
mixture was separated in separatory funnel. Tetrakis(diethylamino)phosphonium bromide13
was obtained after organic layer was concentrated under vacuum.
The tetrakis(diethylamino)phosphonium bromide obtained (0.03 mol) was dissolved
in H2O (30 mL) and this solution was treated with a solution of NH4PF6 (0.033 mol) in H2O
(10 mL). The resulting mixture was stirred for 2 h at room temperature. After decanting
the supernatant, the salt was diluted with dichloromethane (30 mL), and this solution was
washed with H2O (2 × 20 mL) and dried over anhydrous magnesium sulfate. Removal of
the solvent under vacuum afforded an oily solid.
All the other tetrakis(dialkylamino)phosphonium salts14,15 were prepared according
to the above-mentioned procedures. All the prepared compounds showed spectroscopic
data (1H, 13C, and 31P NMR) in accordance with the assigned structure.
{[N(C2H5)2] 4P}PF6: Tetrakis(diethylamino)phosphonium hexafluorophos-
phate. mp 45.7 ◦C 1H NMR (400 MHz, CD3Cl) δ: 1.22 (t, J = 8 Hz, 24H, CH3), 3.15 (dq,
J1 = 4 Hz, J2 = 8 Hz, 16H, CH2). 13C NMR (100 MHz, CD3Cl) δ: 13.2 (JP-C = 2 Hz,

2264
D. WANG ET AL.
CH2), 40.5 (JP-C = 4 Hz, CH3). 31P NMR (162 MHz, CD3Cl) δ: −143.76 (JP-F = 712.8
Hz), 44.60. IR (KBr) 2984.0, 2943.9, 1021.2, 875.2, 837.8 cm−1
.
{[N(C2H5)2]3[N(C4H9)2]P}PF6:(Dibutylamino)tris(diethylamino)phosphonium
◦
1
hexafluorophosphate. mp −23.3 C. H NMR (400 MHz, CD3Cl) δ: 0.95 (t, J = 8 Hz,
6H, CH3), 1.18 (t, J = 8 Hz, 18H, CH3), 1.32 (m, 4H, CH2), 1.54 (m, 4H, CH2), 2.97 (dt,
J1 = 12 Hz, J2 = 16 Hz, 4H, CH2), 3.12 (dq, J1 = 8 Hz, J2 = 12 Hz, 12H, CH2). 13C
NMR (100 MHz, CD3Cl) δ: 13.2 (JP-C = 3 Hz, CH3), 13.7 (CH3), 20.2 (CH2), 30.1 (JP-C
=
3 Hz, CH2), 40.5 (JP-C = 4 Hz, CH2), 46.7 (JP-C = 4 Hz, CH2). 31P NMR (162 MHz,
CD3Cl) δ: −143.76 (JP-F = 712.8 Hz), 44.50. IR (KBr) 2964.8, 2876.2, 1021.0, 874.4,
839.7 cm−1
.
{[N(C2H5)2]3[N(C6H13)2]P}PF6: Tris(diethylamino)(dihexylamino)phosphonium
hexafluorophosphate. Mp −80.00 ◦C.1H NMR (400 MHz, CD3Cl) δ: 0.91 (t, J = 8 Hz,
6H, CH3), 1.20 (t, J = 8 Hz, 18H, CH3), 1.30 (m, 12H, CH2), 1.54 (m, 4H, CH2), 2.97 (dt,
J1 = 12 Hz, J2 = 20 Hz, 4H, CH2), 3.14 (dq, J1 = 8 Hz, J2 = 12 Hz, 12H, CH2). 13C NMR
(100 MHz, CD3Cl) δ: 13.3 (JP-C = 3 Hz, CH3), 13.9 (CH3), 22.5 (CH2), 26.3 (CH2), 28.1
(JP-C = 3 Hz, CH2), 31.4 (CH2), 40.6 (JP-C = 4 Hz, CH2), 47.0 (JP-C = 3 Hz, CH2). 31P
NMR(162 MHz, CD3Cl) δ: −143.72 (JP-F = 712.8 Hz), 44.48. IR (KBr) 2933.5, 2873.2,
1020.6, 874.4, 840.1 cm−1
.
{[N(C2H5)2]3[N(C8H17)2]P}PF6:Tris(diethylamino)(dioctylamino)phosphonium
◦
hexafluorophosphate. mp −23.5 C.1H NMR (400 MHz, CD3Cl) δ: 0.87 (t, J = 8 Hz,
6H, CH3), 1.30 (t, J = 8 Hz, 18H, CH3), 1.28 (m, 20H, CH2), 1.54 (m, 4H, CH2), 3.01
(dt, J1 = 12 Hz, J2 = 20 Hz, 4H, CH2), 3.14 (dq, J1 = 4 Hz, J2 = 8 Hz, 12H, CH2). 13
C
NMR (100 MHz, CD3Cl) δ: 13.2 (JP-C = 3 Hz, CH3), 14.0 (CH3), 22.5 (CH2), 27.0 (CH2),
29.1 (JP-C = 6 Hz, CH2), 31.6 (CH2), 39.9 (CH2), 40.6 (JP-C = 4 Hz, CH2), 47.0 (JP-C
=
4 Hz, CH2). 31P NMR (162 MHz, CD3Cl) δ: −143.72 (JP-F = 712.8 Hz), 44.48. IR (KBr)
2928.3, 2858.4, 1020.9, 875.0, 840.3 cm−1
.
{[N(C4H9)2]4P}PF6: Tetrakis(dibutylamino)phosphonium hexafluorophos-
phate. mp 115.2 ◦C.1H NMR (400 MHz, CD3Cl) δ: 0.97 (t, J = 8 Hz, 24H, CH3), 1.33 (m,
16H, CH2), 1.52 (m, 16H, CH2), 2.97 (dt, J1 = 8 Hz, J2 = 16 Hz, 16H, CH2). 13C NMR
(100 MHz, CD3Cl) δ: 13.8 (CH3), 20.3 (CH2), 30.4 (JP-C = 2 Hz, CH2), 47.1 (JP-C
=
3 Hz, CH2). 31P NMR (162 MHz, CD3Cl) δ: –143.67 (JP-F = 712.8 Hz), 44.31. IR (KBr)
2961.3, 2874.3, 1037.8, 872.3, 838.8 cm−1
.
{[N(C4H9)2]3[N(C6H13)2]P}PF6:Tris(dibutylamino)(dihexylamino)phosphonium
hexafluorophosphate. mp 45.7 ◦C.1H NMR (400 MHz, CD3Cl) δ: 0.89 (t, J = 8 Hz, 6H,
CH3), 0.94 (t, J = 8 Hz, 18H, CH3), 1.30 (m, 24H, CH2), 1.51 (m, 16H, CH2), 2.97 (dt, J1 =
8 Hz, J2 = 16 Hz, 16H, CH2). 13C NMR (100 MHz, CD3Cl) δ: 13.8 (CH3), 13.9 (CH3),
20.3 (CH2), 22.5 (CH2), 26.7 (CH2), 28.4 (CH2), 30.4 (CH2), 31.5 (CH2), 47.0 (JP-C
3 Hz, CH2), 47.3 (JP-C = 4 Hz, CH2). 31P NMR (162 MHz, CD3Cl) δ: −143.68 (JP-F
=
=
712.8 Hz), 44.31. IR (KBr) 2958.7, 2873.4, 1038.1, 873.2, 840.1 cm−1
.
{[N(C4H9)2]3[N(C8H17)2]P}PF6:Tris(dibutylamino)(dioctylamino)phosphonium
◦
hexafluorophosphate. mp −80.0 C.1H NMR (400 MHz, CD3Cl) δ: 0.87 (t, J = 8 Hz,
6H, CH3), 0.94 (t, J = 8 Hz, 18H, CH3), 1.31 (m, 32H, CH2), 1.51 (m, 16H, CH2), 2.95
(dt, J1 = 8 Hz, J2 = 16 Hz, 16H, CH2). 13C NMR (100 MHz, CD3Cl) δ: 13.8 (CH3), 14.0
(CH3), 20.3 (CH2), 22.6 (CH2), 27.0 (CH2), 28.4 (CH2), 29.1 (CH2), 30.3 (CH2), 31.7
(CH2), 47.0 (JP-C = 3 Hz, CH2), 47.2 (JP-C = 4 Hz, CH2). 31P NMR (162 MHz, CD3Cl) δ:
−143.70 (J = 907.2 Hz), 44.30. IR (KBr) 2931.4, 2873.1, 1037.3, 874.0, 840.9 cm−1
.
{[N(C5H10)]3[N(C2H5)2]P}PF6: (Diethylamino)tri(piperidin-1-yl)phosphonium
hexafluorophosphate. mp 64.9 ◦C. 1H NMR (400 MHz, CD3Cl) δ: 1.22 (t, J = 8 Hz, 6H,

Rh(PPh3)3Cl/TETRAKIS(DIALKYLAMINO)PHOSPHONIUM SALTS
2265
CH3), 1.69 (m, 18H, CH2), 3.11 (dq, J1 = 12 Hz, J2 = 20 Hz, 4H, CH2), 3.18 (dt, J1 = 8
Hz, J2 = 12 Hz, 12H, CH2).13C NMR (100 MHz, CD3Cl) δ: 13.4 (JP-C = 2 Hz, CH3), 23.7
(CH2), 25.6 (JP-C = 5 Hz, CH2), 40.4 (JP-C = 4 Hz, CH2), 46.9 (JP-C = 4 Hz, CH2). 31
P
NMR (162 MHz, CD3Cl) δ: −143.68 (JP-F = 712.8 Hz), 39.21. IR (KBr) 2938.3, 2858.5,
1022.4, 961.9, 838.3 cm−1
.
{[N(C5H10)]3[N(C4H9)2]P}PF6: (Dibutylamino)tri(piperidin-1-yl)phosphonium
hexafluorophosphate. mp 134.9 ◦C. 1H NMR (400 MHz, CD3Cl) δ: 0.97 (t, J = 8 Hz, 6H,
CH3), 1.36 (m, 4H, CH2), 1.55 (m, 4H, CH2), 1.69 (m, 18H, CH2), 2.98 (dt, J1 = 8 Hz, J2 =
12 Hz, 4H, CH2), 3.10 (dt, J1 = 8 Hz, J2 = 12 Hz, 12H, CH2). 13C NMR (100 MHz, CD3Cl)
δ: 13.9 (CH3), 20.3 (CH2), 23.7 (CH2), 25.7 (JP-C = 5 Hz, CH2), 30.4 (JP-C = 2 Hz, CH2),
46.6 (JP-C = 4 Hz, CH2), 47.0 (JP-C = 4 Hz, CH2).31P NMR (162 MHz, CD3Cl) δ: −143.68
(JP-F = 712.8 Hz), 39.13. IR (KBr) 2938.3, 2858.6, 1026.4, 961.7, 838.8 cm−1
.
{[N(C5H10)]3[N(C6H13)2]P}PF6: (Dihexylamino)tri(piperidin-1-yl)phosphonium
hexafluorophosphate. mp 91.9 ◦C.1H NMR (400 MHz, CD3Cl) δ: 0.92 (t, J = 8 Hz, 6H,
CH3), 1.31 (m, 12H, CH2), 1.56 (m, 4H, CH2), 1.61 (m, 12H, CH2), 1.69 (m, 6H, CH2),
2.97 (dt, J1 = 8 Hz, J2 = 12 Hz, 4H, CH2), 3.11 (dt, J1 = 8 Hz, J2 = 12 Hz, 12H, CH2).13C
NMR (100 MHz, CD3Cl) δ: 13.9 (CH3), 22.5 (CH2), 23.7 (CH2), 25.7 (JP-C = 5 Hz, CH2),
26.7 (CH2), 28.4 (JP-C = 2 Hz, CH2), 31.5 (CH2), 46.9 (JP-C = 3 Hz, CH2), 47.0 (JP-C
=
4 Hz, CH2).31P NMR (162 MHz, CD3Cl) δ: −143.67 (JP-F = 712.8 Hz), 39.04. IR (KBr)
2933.7, 2961.8, 1025.5, 961.4, 838.4 cm−1
.
{[N(C5H10)]3[N(C8H17)2]P}PF6: (Dioctylamino)tri(piperidin-1-yl)phosphonium
◦
hexafluorophosphate. mp 70.8 C.1H NMR (400 MHz, CD3Cl) δ: 0.89 (t, J = 8 Hz,
6H, CH3), 1.29 (m, 20H, CH2), 1.62 (m, 22H, CH2), 2.99 (dt, J1 = 8 Hz, J2 = 12 Hz, 4H,
CH2), 3.10 (dt, J1 = 8 Hz, J2 = 12 Hz, 12H, CH2).13C NMR (100 MHz, CD3Cl) δ: 14.1
(CH3), 22.6 (CH2), 23.7 (CH2), 25.7 (JP-C = 5 Hz, CH2), 27.0 (CH2), 28.4 (CH2), 29.1
(JP-C = 2 Hz, CH2), 31.7 (CH2), 45.8 (JP-C = 4 Hz, CH2), 47.0 (JP-C = 4 Hz, CH2).31P
NMR (162 MHz, CD3Cl) δ: −143.66 (JP-F = 712.8 Hz), 39.06. IR (KBr) 2932.8, 2854.5,
1025.9, 961.2, 837.8 cm−1
.
Preparation of Tetrakis(Dialkylamino)Phosphonium Salts
Supported Catalyst
The typical procedure for preparation of tetrakis(dialkylamino)phosphonium salts
supported catalyst was as follows: 0.4 g of the required tetrakis(dialkylamino)phosphonium
salt was mixed with 2.0 mg of Rh(PPh3)3Cl, then the mixture was heated to about 100–120
◦C and stirred for 2 h under nitrogen. After cooling to room temperature, the resulting solid
was ground up and used as a catalyst for the hydrosilylation of alkylene with silane.
Hydrosilylation of Alkylene With Triethoxysilane
Typical hydrosilylation reaction procedures were as follows: a given amount of
catalyst was introduced into a 10 mL round bottomed flask equipped with magnetic stirring,
then, the alkene and silane were added. The hydrosilylation reaction was allowed to proceed
◦
with constant stirring at 95 C for 2 h. At the end of the reaction, the product phase was
separated from the catalyst system by decantation, and the conversion of alkene and the
selectivity were determined by GC/MS. The catalyst system was recharged with fresh
alkene and silane for the next catalytic run.

2266
D. WANG ET AL.
REFERENCES
1. Broeke, J. V. D.; Winter, F.; Deelman, B. J.; Koten, G. V. Org. Lett. 2002, 4, 3851–3854.
2. Marciniec, B.; Gulinski, J. J. Organomet. Chem. 1983, 253, 349–362.
3. Onopchenko, A.; Sabourin, E. T.; Beach, D. L. J. Org. Chem. 1983, 48, 5101–5105.
4. Chauvin, Y.; Mussmann, L.; Olivier, H. Angew. Chem. Int. Ed. 1996, 34, 2698–2700.
5. Mehnert, C. P.; Cook, R. A.; Dispenziere, N. C.; Afeworki, M. J. Am. Chem. Soc. 2002, 124,
12932–12933.
6. Weyershausen, B.; Hell, K.; Hesse, U. Green Chem. 2005, 7, 283–287.
7. Peng, J.; Li, J.; Bai, Y.; Qiu, H.; Jiang, K.; Jiang, J.; Lai, G. Catal. Commun. 2008, 9, 2236–2238.
8. Li, J.; Peng, J.; Bai, Y.; Zhang, G.; Lai, G.; Li, X. J. Organomet. Chem. 2010, 695, 431–436.
9. Wasserscheid, P.; Keim, W. Angew. Chem., Int. Ed. Engl. 2000, 39, 3772–3789.
10. Fan, X. S.; Li, Y. Z.; Zhang, X. Y.; Hu, X. Y.; Wang, J. J. Chin. J. Org. Chem. 2005, 25,
1482–1486.
11. Suarez, P. A. Z.; Dullius, J. E. L.; Einloft, S.; De Souza, R. F.; Dupont, J. Polyhedron. 1996, 15,
1217–1219.
12. Huang, S.; Xie, R. G.; Tian, B. Z.; Qin, S. Y., The Preparation of Organic Synthetic Reagents
(Sichuan University Press, Chengdu, 1988), pp. 156–158.
13. Zhao, W. J.; Li, Y. M.; Zhang, H.; Wang, X. J.; Na, Q. Fine Chemicals 2003, 20, 407–409.
14. Sergej, P.; Wolfgang, A.; Ralf, P.; Thomas, W.; Thomas, S.; Hans, S. Ger. Offen. 1998, DE:
19702282.
15. Kazuki, M.; Kumiko, S.; Yuan, G. PCT Int. Appl. 2007, WO, 2007063959.