New strategies to phosphino-phosphonium cations and zwitterions

Article abstract of DOI:10.1002/chem.200902369

By employing strategies based on frustrated Lewis pair chemistry, new routes to phosphino-phosphonium cations and zwitterions have been developed. B(C₆F₅)₃ is shown to react with H₂ and P₂tBu₄ to effect heterolytic hydrogen activation yielding the phosphino-phosphonium borate salt [(tBu₂P)PHtBu ₂][HB(C₆F₅)₃] (1). AI-ternatively, alkenylphosphino-phosphonium borate zwitterions are accessible by reaction of B(C₆F₅)₃ and PhC≡CH with P ₂Ph₄,P₄Cy₄,orP₅Ph ₅ affording the species [(Ph₂P)P(Ph)₂C(Ph)= C(Ph)=C(H)B(C₆F₅)₃](3), and [(P ₄Ph₄)P(Ph)C(Ph)=C(H)B(C₆F₅) ₃] (4). A related phosphino-phosphonium borate species-[(Ph ₄P₄)P(Ph)C₆F₄B-(F)(C ₆F₅)₂](5) is also isolated from the thermolysis of B(C₆F₅)₃ and P₅Ph₅.

Full text of DOI:10.1002/chem.200902369

DOI: 10.1002/chem.200902369
New Strategies to Phosphino–PhosACTHNUTRGNEUGNphonium Cations and Zwitterions
Stephen J. Geier, Meghan A. Dureen, Eva Y. Ouyang, and Douglas W. Stephan*[a]
Dedicated to Professor M. Lappert on the occasion of his 80th birthday
Abstract: By employing strategies
based on frustrated Lewis pair chemis-
try, new routes to phosphino-phospho-
nium cations and zwitterions have been
ternatively, alkenylphosphino-phospho-
nium borate zwitterions are accessible
with P2Ph4, P4Cy4, or P5Ph5 affording
the
C(H)BACHTNUGTRENNUNG
C(Ph)=C(H)BCAHTUNGTRENNNUG
species
(C6F5)3] (2), [(P3Cy3)P(Cy)-
(C6F5)3] (3), and
[(P4Ph4)P(Ph)C(Ph)=C(H)B(C6F5)3]
[(Ph2P)P(Ph)2C(Ph)=
ꢀ
by reaction of B
N
developed. B
N
ACHTUNGTRENNUNG
Keywords: alkyne activation · hy-
drogen activation · main group ele-
ments · phosphino-phosphonium ·
phosphorus · zwitterions
with H2 and P2tBu4 to effect heterolytic
hydrogen activation yielding the phos-
(4). A related phosphino-phosphonium
borate species—[(Ph4P4)P(Ph)C6F4B-
(F)(C6F5)2] (5) is also isolated from the
phino-phosphonium
borate
salt
[(tBu2P)PHtBu2] [HB
A
thermolysis of BACTHUNGTERN(NUG C6F5)3 and P5Ph5.
Introduction
while several other groups described the generation of phos-
phino-phosphonium monocations of the form [R3PPR2]+.[10]
Over the past decade, Burford and co-workers have report-
ed an extensive series of linear and cyclic polyphosphino-
phosphonium mono and dications.[11] These syntheses have
been achieved by direct alkylation or by halide abstraction
from chlorophosphine in the presence of a tertiary phos-
phine. Very recently, Weigand et al.[12] have extended this
chemistry to intercept phosphenium cations with P4, and
thereby developing a clever approach to the cationic clusters
There has been a surge in the interest in main-group chemis-
try in the last decade. Much of this has been a result of the
discovery of facile routes to unusual oxidation states or co-
ordination geometries as well as the unveiling of new reac-
tivity and unprecedented application of main group com-
pounds in catalysis. While this renaissance has involved
many other main group elements, P in particular has attract-
ed much attention. Among a number of very recent papers
that have contributed to the excitement in phosphorus
chemistry,[1] Cummins et al.[2] have developed creative and
elegant metal-mediated syntheses of the various P4ÀxAsx spe-
cies; Shaffer et al.[3] have reported the characterization of
nanostructures derived from elemental P, and the groups of
Robinson and Bertrand have unveiled new P-based chains[4]
and clusters[5] stabilized by carbene ligands.[6] Despite the
focus of this recent flurry of activity on systems incorporat-
[Ph2P5]+, [Ph4P6]2+, and [Ph6P7]3+
.
We have recently shown that in systems where classical
Lewis acid–base adduct formation can be precluded by the
use of sterically demanding Lewis donors and acceptors, un-
precedented reactivity can result.[13] For example, such “frus-
trated Lewis pairs” have been shown to afford unusual aro-
matic substitution products[14] as well as exhibit unique reac-
tivity with H2,[14b,15] olefins,[16] alkynes,[17] CO2,[18] and N2O.[19]
Herein, we demonstrate that diphosphines P2R4 (R=tBu,
Ph) and cyclic polyphosphines P4Cy4 and P5Ph5 react with
À
ing P P bonds, related neutral and anionic polyphosphines
were pioneered by Baudler and co-workers in the 1960s and
1970s.[7] In the 1980s Schmidpeter et al.[8] and Schmutzler et
the Lewis acid B
ACHTUGNTERN(NUNG C6F5)3 effecting H2 or alkyne activation, as
al.[9] reported dicationic species of the form [(R3P)2PH]2+
,
well as with B(C6F5)3 alone under thermolysis conditions.
ACHTUNGTRENNUNG
This presents new synthetic routes to functionalized phos-
phino-phosphonium salts and zwitterions.
[a] S. J. Geier, M. A. Dureen, E. Y. Ouyang, Prof. Dr. D. W. Stephan
Department of Chemistry
Results and Discussion
University of Toronto
80 St. George Street, Toronto, ON, M5S3H6 (Canada)
E-mail: dstephan@chem.utoronto.ca
BACHTUNGTRENNUNG
988
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Chem. Eur. J. 2010, 16, 988 – 993

FULL PAPER
these Lewis basic centers and the borane Lewis acid accord-
ing to the results of multinuclear NMR spectroscopy. Expo-
sure of this mixture to H2 results in the clean formation of a
new species (1). The 31P{1H} signals of 1 were observed at
À
d=35.0 and 69.7 ppm with a P P coupling constant of
464 Hz, while the 31P NMR spectrum reveals that the signal
À
at d=35.0 ppm also exhibits a P H coupling of 395 Hz. The
1
À
corresponding H NMR signal for this P H fragment ap-
pears at d=5.27 ppm. In addition a quartet resonance at d=
3.67 ppm (1JBÀH =91 Hz) was attributed to a B H fragment.
À
The corresponding 11B and 19F spectra showed resonances at
d=À25.3 ppm and d=À133.1, À164.0, and À166.9 ppm, re-
spectively, consistent with the presence of the anion [HB-
(C6F5)3][20] and prompting the formulation of
1
as
À
Figure 1. POV-ray drawing of 2. Selected bond lengths [ꢁ]: B(1) C(1)
[(tBu2P)PHtBu2][HBAHCTNUTGREGN(NUN C6F5)3] (Scheme 1). This connectivity
À
À
À
1.642(3), C(1) C(2) 1.346(3), C(2) P(1) 1.8069(19), P(1) P(2) 2.2355(8).
was subsequently confirmed by crystallographic data, al-
though disorder within the cation precludes a detailed con-
sideration of the metric parameters.
acid by multinuclear NMR spectroscopy between À608C
and 408C. As a result we sought to exploit these systems to
effect the conversion to phosphino-phosphonium deriva-
tives.
ꢀ
To this end, PhC CH was added to a solution containing
(C6F5)3 and P4Cy4. A yellow powder was subsequently iso-
B
N
lated in 78% yield, which was determined to be the species
3 (Scheme 2b). The 31P NMR spectrum of 3 shows three res-
Scheme 1. Reactions of P2R4 affording 1 and 2.
By employing a similar strategy, BACHTNUTRGNEUNG(C6F5)3 was added to a
ꢀ
mixture of PhC CH and P2Ph4 in toluene. Subsequent con-
centration of the mixture afforded colorless crystals of a
1
new species (2) in 68% isolated yield. The H NMR spec-
trum of 2 contained a doublet resonance at d=8.29 ppm at-
À
tributable to an olefinic C H that exhibited coupling to P of
37 Hz. Compound 2 also gave rise to an upfield 11B reso-
nance at d=À16.1 ppm and 19F signals attributable to the
fluoroarene rings. The corresponding 31P{1H} signals were
1
observed at d=21.4 and À13.2 ppm with a JPÀP coupling of
330 Hz. These data support the formulation of
2 as
[(Ph2P)P(Ph)2C(Ph)=C(H)BACHTNUGRTNEUNG(C6F5)3]. This notion was subse-
quently confirmed crystallographically (Figure 1). The struc-
tural data affirms that the diphosphine and borane have
added to the alkyne affording a zwitterionic species that is
best described as an alkenyl-phosphino-phosphonium
borate. One of the P centers of the diphosphine adds to the
phenyl-sustituted carbon atom of the alkyne, while the
borane has added to the unsubstituted end of the alkyne, af-
fording a trans-orientation of the B and P about the result-
ing olefinic C=C bond. The metric parameters about the al-
Scheme 2. Alkyne activation and thermolysis of cyclopolyphosphines and
BACHTUNRTGNEUNG(C6F5)3 affording 3–5.
onances at d=20.4, À47.2, and À59.4 ppm, in a ratio of
1:2:1 (Figure 2), characteristic of an AB2X spin system. The
À
P P couplings clearly indicated quaternization of a P center
À
giving rise to the downfield resonance. The one-bond P P
À
kenyl borate are typical of such species. The P P bond
coupling constant associated with the cationic P center is
À
length is 2.2355(8) ꢁ, which is significantly longer than
roughly double the other one-bond P P coupling constant
those reported for [Ph2PMe
N
(247 Hz, vs. 123 Hz), consistent with the trends noted for
[P4Ph4PRR’]+ ions.[11] The 19F and 11B NMR spectra of 3 are
similar to those described for 2, and thus infer the presence
of a borate fragment. Similarly, the 1H NMR spectrum
shows the expected resonances for the cyclohexyl groups as
[Ph2PCl
ACHTUNGTRENNUNG
withdrawing nature of the alkenyl-borate substituent in 2.
Although P5Ph5 has been shown to form Lewis acid–base
adducts with BH3,[21] the combination of P4Cy4 or P5Ph5 with
À
B
G
well as a signal attributable to an olefinic C H with a cou-
Chem. Eur. J. 2010, 16, 988 – 993
ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
989

D. W. Stephan et al.
other PPh units; thus, overall there exists a ABCDX spin
system. Aside from the resonance attributed to the cationic
phosphorus center, the signals in the 31P NMR spectrum
were second order and overlapped, typical of related P5
cations.[11 l] The formulation of 4 was unambiguously con-
firmed by X-ray crystallography to be the zwitterionic tetra-
phosphino-phosphonium
borate
addition
product
[(Ph4P4)P(Ph)C(Ph)=C(H)BAHCTUNTGERGN(NUN C6F5)3] (Figure 4), in which the
À
P5Ph5 and BACHTNUTRGEN(UNG C6F5)3 have added to the alkyne. The B C, C=
Figure 2. 31P NMR spectrum of 3.
pling to P of 37 Hz and a phenyl group. These data support
the formulation of 3 as the triphosphino-phosphonium
borate [(P3Cy3)P(Cy)C(Ph)=C(H)
BACHTNGUTERNNU(G C6F5)3] (Scheme 2).
Crystallographic data confirmed this formulation (Figure 3).
À
Figure 4. POV-ray drawing of 4. Selected bond lengths [ꢁ]: B(1) C(19)
À
À
À
1.640(3), C(19) C(20) 1.337(3), C(20) P(1) 1.821(2), P(1) P(2)
À
À
À
2.2137(8), P(2) P(3) 2.2190(8), P(3) P(4) 2.2227(9), P(4) P(5) 2.2188(8),
À
P(5) P(1) 2.2077(8).
À
C, and P C bond lengths in 4 were similar to those in 2.
À
The P P bond lengths lengthen with increasing bonds from
À
À
the quaternary P center. Thus, the P(1) P(2) and P(1) P(5)
are comparatively short, averaging 2.2107(8) ꢁ, whereas
À
À
À
P(2) P(3) and P(4) P(5) average 2.2189(8) ꢁ, and P(3)
P(4) is found to be 2.2227(9) ꢁ. A similar metric trend was
described by Burford et al. for the cyclotetraphosphino-
phosphonium cation [(Ph4P4)P(Ph)Me]+,[11f] although the P
P bonds involving P(1) are somewhat longer in 4, again as a
À
À
Figure 3. POV-ray drawing of 3. Selected bond lengths [ꢁ]: B(1) C(19)
result of the electron-withdrawing nature of the alkenyl
borate substituent.
À
À
À
1.647(6), P(1) C(20) 1.818(4), C(19) C(20) 1.341(5), P(1) P(3)
À
À
À
2.1990(15), P(1) P(2) 2.2106(15), P(2) P(4) 2.2331(16), P(3) P(4)
2.2266(16).
ꢀ
In the absence of PhC CH, the combination of B
and P5Ph5 did react under prolonged heating for six days at
G
À
The newly formed B C bond is 1.647(6) ꢁ, while the corre-
1208C in toluene. This resulted in quantitative formation of
À
sponding P C bond length is 1.818(4) ꢁ, both of which are
the zwitterion [(Ph4P4)P(Ph)C6F4B(F)
me 2c). This species, derived from the attack at the para-po-
sition[14a,15d,22] of one of the fluoroarene rings of B
(C6F5)3
ACHTNUGTNER(NGNU C6F5)2] (5) (Sche-
typical. The olefinic C=C bond length is also typical at
À
1.341(5) ꢁ. The P P bonds of the P4 ring range from
ACHTUNGTRENNUNG
2.1990(15) to 2.2331(16) ꢁ, similar to that described for 2.
with concurrent F transfer to B, was isolated in 95% yield.
This structural assignment was supported by observations
of a broad signal for the B-F fluorine in the 19F NMR spec-
trum at d=À193.1 ppm, a doublet (1JBÀF =52 Hz) in the
11B NMR spectrum at d=À2.7 ppm, and a downfield triplet
in the 31P NMR spectrum at d=13.3 ppm (1JPÀP =359 Hz).
Similar to 4, only the resonance attributed to the cationic
phosphorus center of this ABDCX spin system is well-re-
solved in the 31P spectrum of 5. This resonance is typical of
cationic P centers in [P4Ph4PRR’]+ ions.[11 l] This formulation
ꢀ
In an analogous fashion, addition of PhC CH to B
N
and P5Ph5 results in the quantitative conversion to a new
species (4) after 4 h (Scheme 2b). This product exhibited a
resonance typical of the olefinic proton in the 1H NMR
spectrum at d=8.59 ppm, which exhibits a coupling to P of
42 Hz. A corresponding downfield triplet in the 31P{1H}
NMR spectrum is observed at d=20.9 ppm (1JPÀP =300 Hz).
This spectrum also displays multiplet resonances at d=
À22.5, À30.8, À35.6, and À38.9 ppm attributable to four
990
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Chem. Eur. J. 2010, 16, 988 – 993

Phosphino-Phosphonium Cations and Zwitterions
FULL PAPER
was further supported by X-ray crystallography (Figure 5).
Most of the metric parameters for the borate[15d] and the
tetra-phosphino-phosphonium.[11 l] portions of the molecule
were similar to those described above. Similar to 4, in 5 the
exploring the utility of such polyphosphine derivatives in
our laboratory.
Experimental Section
General considerations: All manipulations were performed on a double
manifold N2 (H2)/vacuum line with Schlenk-type glassware or in an N2-
filled inert atmospheres glove box. The N2 and H2 gases were dried by
passage through a Dririte column. Solvents (Aldrich) were dried using an
Innovative Technologies solvent system (toluene, hexanes, pentane,
CH2Cl2). NMR spectra were obtained on a Bruker Avance 300 MHz
spectrometer and spectra were referenced to residual solvent (1H, 13C) or
externally (11B; BF3OEt2; 19F; CFCl3; 31P; 85% H3PO4). NMR solvents
were purchased from Cambridge Isotopes, dried over CaH2 (CD2Cl2 and
CDCl3), vacuum distilled prior to use and stored over 4 ꢁ molecular
sieves in the glovebox. tBu2PPtBu2 was generated from reaction of
tBu2PLi with tBu2PCl, P4Cy4 and P5Ph5 were prepared as previously de-
scribed.[7] P2Ph4 was purchased from Aldrich and used as received. B-
AHCTUNGTRENNUNG
A
BACHTUNGTRENNUNG
0.20 mmol) was added to P2tBu4 (28 mg, 0.20 mmol) in toluene (2 mL).
The pink solution was subjected to three freeze–pump–thaw cycles and
backfilled with H2 at 77 K (ca. 4 atm). The solution was allowed to stir
overnight and then pumped to dryness. The solid was washed with pen-
tane (2ꢂ2 mL) and again pumped to dryness. Yield: 64 mg (74%).
1H NMR (CDCl3): d=1.46 (dd, 3JPÀH =14 Hz, 4JPÀH =2 Hz, 18H, C-
À
Figure 5. POV-ray drawing of 5. Selected bond lengths [ꢁ]: B(1) C(13)
À
À
À
1.661(9), C(16) P(1) 1.808(6), P(1) P(2) 2.216(2), P(2) P(3) 2.242(2),
À
À
À
À
P(3) P(4) 2.238(2), P(4) P(5) 2.228(2), P(5) P(1) 2.200(2), B(1) F(15)
1.422(8).
ACHUTNRGENNUG CAHTUNTGREN(NUGN CH3)3), 3.67 (q,
(CH3)3), 1.57 (dd, 3JPÀH =15 Hz, 4JPÀH =1 Hz, 18H, C
1JBÀH =91 Hz, 1H, BH), 5.27 ppm (dd, 1JPÀH =395 Hz, 2JPÀH =8 Hz, 1H,
PH); 19F NMR (CDCl3): d=À133.1 (br d, 3JFÀF =23 Hz, 6F, o-C6F5),
À164.0 (t, 3JFÀF =20 Hz, 3F, p-C6F5), À166.9 ppm (tm, 3JFÀF =23 Hz, 6F,
m-C6F5); 31P{1H} NMR (CDCl3): d=35.0 (d, 1JPÀP =464 Hz,
tBu2PPHtBu2), 69.7 ppm (d, 1JPÀP =464 Hz, tBu2PPHtBu2); 11B NMR
(CDCl3): d=À25.3 ppm (d, 1JBÀH =91 Hz); 13C NMR (CDCl3): d=31.4
À
À
P(1) P(5) and P(1) P(2) bond lengths of 2.216(2) ꢁ and
2.200(2) ꢁ are significantly longer than those in
[(Ph4P4)P(Ph)Me]+,[11f] reflecting the electron-withdrawing
nature of the fluoroarene substituent. The P5 ring adopts a
pseudo-chair conformation with the phenyl rings on P(1)
and P(2) cis disposed; the remaining substituents adopt al-
ternating trans-dispositions. The phenyl ring on P(5) is ori-
ented approximately parallel to the fluoroarene ring on the
cationic P center (P(1)). The distance between these rings
reflects some degree of p-stacking of these electron-rich and
electron-poor rings.[23] It is noteworthy that the structures of
4 and 5 infer that quaternization of P in the P5 ring occurs
at one of the two P atoms where the Ph groups are disposed
in a cis orientation. A similar observation was made by Bur-
ford et al. for alkylation reactions.[11l]
(dd, JPÀC =15 Hz, JPÀC =6 Hz, C
7 Hz, C(CH3)3), 36.8 (dd, JPÀC =7 Hz, JPÀC =7 Hz, C
PÀC =11 Hz, JPÀC =7 Hz, C(CH3)3), 125.2 (br m, B-C), 136.3 (dm, JFÀC
240 Hz, C-F), 137.7 (dm, 1JFÀC =240 Hz, C-F), 148.3 ppm (dm, JFÀC
G
=
E
ACHTUNGTRENNUNG
1
J
E
=
=
1
240 Hz, C-F); elemental analysis calcd (%) for C34H38BF15P2: C 50.77, H
4.76; found: C 50.34, H 4.68.
Synthesis of E-[(Ph2P)P(Ph)2C(Ph)=C(H)BACHTUNGRTNEUNG(C6F5)3] (2): A solution of
tris(pentafluorophenyl)borane (50 mg, 0.098 mmol) in toluene (5 mL)
was added dropwise to a solution of tetraphenylbiphosphine (36 mg,
0.097 mmol) and phenylacetylene (30 mg, 0.29 mmol) in toluene (5 mL).
The solution was stirred for 30 min and the volume of the reaction mix-
ture was reduced to 2 mL under reduced pressure. The solution was left
at room temperature overnight to afford clear colorless crystals, which
were washed with pentane (2ꢂ2 mL) and dried in vacuo (65 mg, 68%).
1H NMR (CD2Cl2): d=6.48 (d, 3JHÀH =8 Hz, 2H), 6.71 (t, 3JHÀH =8 Hz,
2H), 6.88 (tm, 3JHÀH =8 Hz, 1H), 7.16 (t, 3JHÀH =8 Hz, 4H), 7.25 (tm,
3
3JHÀH =8 Hz, 4H), 7.32–7.54 (m, 10H), 7.69 (m, 2H), 8.29 ppm (d, JHÀP
=
37 Hz, 1H, C=C-H); 11B NMR (CD2Cl2): d=À16.1 ppm (s, br); 19F NMR
Conclusions
3
(CD2Cl2): d=À131.3 (d, 6F, 3JFÀF =21 Hz, o-C6F5), À162.8 (t, 3F, JFÀF
=
21 Hz, p-C6F5), À167.0 ppm (d, 6F, 3JFÀF =20 Hz, m-C6F5); 31P{1H} NMR
The above formations of 1–5 demonstrate that the steric de-
mands of diphosphines and cyclopolyphosphines can be ex-
ploited in frustrated Lewis pair chemistry to achieve H2 or
alkyne activation, and aromatic substitution on a fluroaryl
group of the borane. These reactions allow the functionali-
zation of polyphosphines affording cations not available
through the use of conventional alkylating agents. As such,
these strategies afford new synthetic routes to phosphino-
phosphonium salts and zwitterions. The ability to incorpo-
rate such functional groups offers the potential for further
(CD2Cl2): d=21.4 (dm, 1JPÀP =330 Hz, C=C-P
(Ph2)-PPh2), À13.2 ppm (d,
1JPÀP =330 Hz, C=C-PPh2-PPh2); elemental analysis calcd (%) for
C47H27BF15P: C 60.30, H 2.42; found: C 60.65, H 2.72; X-ray data: P21/c,
a=11.9649(6), b=12.9141(6), c=28.8636(15) ꢁ, b=100.425(3)8, V=
4386.3(4) ꢁ3, Z=4, data: 8802, parameters: 614, R
ACHTUNGTRENNUNG
0.0931, GOF: 1.007.
Synthesis of E-
N
ACHTNUGNRET(NGNU C6F5)3] (3): To a
(À358C) solution of B
AHCTUNGTRENNUNG
0.048 mmol) in CH2Cl2 was added phenyl acetylene (20 mg, 0.20 mmol)
dropwise. The pale yellow solution was allowed to stir overnight, the sol-
vent was removed in vacuo, and the residue was washed with pentane
1
(1 mL), leaving a yellow powder. Yield: 41 mg (78%). H NMR (CDCl3):
À
chemistry of these P P-bonded systems. We are currently
d=1.00 (m, 2H), 1.10–1.37 (m, 18H), 1.55–1.95 (m, 21H), 2.05 (m, 1H),
Chem. Eur. J. 2010, 16, 988 – 993
ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
991

D. W. Stephan et al.
3
2.34 (m, 2H), 6.88 (d, 3JHÀH =7 Hz, 2H, ortho-C6H5), 7.11 (t, JHÀH
=
the isotropic temperature factor of the C atom to which they are bonded.
The H-atom contributions were calculated, but not refined. The locations
of the largest peaks in the final difference Fourier map calculation as
well as the magnitude of the residual electron densities in each case were
of no chemical significance. Additional details are provided in the Sup-
porting Information.
7 Hz, 2H, m-C6H5), 7.19 (tm, 3JHÀH =7 Hz, 1H, para-C6H5), 8.30 ppm (d,
3JPÀH =37 Hz, C=C-H 19F NMR (CDCl3): d=À130.6 (d, 3JFÀF =24 Hz, o-
C6F5), À161.7 (t, 3JFÀF =22 Hz, p-C6F5), À165.9 ppm (t, 3JFÀF =23 Hz, m-
1
1
C6F5); 31P NMR (CDCl3): d=20.4 (t, JPÀ P =247 Hz), À47.2 (dd, JPÀ
=
P
247 Hz, J=123 Hz, 2P), À59.4 ppm (t, J=123 Hz, 1P); 11B NMR
(CDCl3): d=À15.9 ppm (br s); elemental analysis calcd (%) for
C50H50BF15P4: C 56.09, H 4.71; found: C 56.26, H 4.94; X-ray data: P21/n,
a=15.6548(11), b=16.7208(10), c=19.0352(13) ꢁ, b=100.341(2)8, V=
4901.7(5) ꢁ3, Z=4, data: 11237, parameters: 631, R
ACHTUNGTRENNUNG
Acknowledgements
(all) 0.1375, GOF: 0.968.
Synthesis of E-[(Ph4P4)P(Ph)C(Ph)=C(H)B
BACHTUNGTRENNUNG(C6F5)3 (55 mg, 0.11 mmol) and P5Ph5 (50 mg, 0.093 mmol) in CH2Cl2
ACHTUNGTRENNUNG
The NSERC of Canada is acknowledged for financial support. S.J.G. is
grateful for the award of an NSERC postgraduate scholarship. D.W.S. is
grateful for the award of a Canada Research Chair from the NSERC and
a Killam Research Fellowship from the Killam Foundation.
was added phenyl acetylene (20 mg, 0.20 mmol). The pale yellow solution
was allowed to stir overnight, the solvent was removed in vacuo, and the
residue was washed with pentane (2ꢂ2 mL), leaving an off-white
powder. Yield: 105 mg (91%). X-ray quality crystals were grown from a
layered solution of CDCl3/pentane. 1H NMR (CD2Cl2): d=5.98 (d, J=
9 Hz, 2H), 6.51 (t, J=8 Hz, 2H), 6.76 (t, J=8 Hz, 1H), 7.01–7.74 (m,
25H), 8.59 ppm (dd, 3JPÀH =42 Hz, J=4 Hz, 1H, C=C-H); 19F NMR
(CD2Cl2): À131.0 (d, 3JFÀF =24 Hz, o-C6F5), À163.1 (t, 3JFÀF =22 Hz, p-
[1] C. A. Russell, Angew. Chem. Int. Ed. 2009, 48, 4895–4897; Angew.
Chem. 2009, 121, 4992–4994.
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Chem. 2007, 119, 7182–7185; Angew. Chem. Int. Ed. 2007, 46, 7052–
7055.
3
C6F5), À167.3 ppm (t, JFÀF =19 Hz, m-C6F5); 31P NMR (CD2Cl2): d=20.9
(t, 1JPÀP =300 Hz), À22.5 (m, 1P), À30.8 (m, 1P), À35.6–38.9 ppm (m,
2P); 11B NMR (CD2Cl2): d=À15.5 ppm (br s);elemental analysis calcd
(%) for C56H31BF15P5: C 58.26, H 2.71; found: C 58.37, H 2.94; X-ray
¯
data: P1, a=12.8543(9), b=12.9762(10), c=18.0053(12) ꢁ, a =74.201(4),
b=76.183(4), g=61.367(4)8, V=2515.5(3) ꢁ3, Z=2, data: 11491, param-
eters: 694, R
Synthesis E-[(Ph4P4)P(Ph)C6F4B(F)
0.55 mmol) was added to a solution of BAHCUTNGTRENNUNG
ACHTUNGTRENNUNG
AHCTUNGTRENNUNG
[5] J. D. Masuda, W. W. Schoeller, B. Donnadieu, G. Bertrand, J. Am.
Chem. Soc. 2007, 129, 14180–14181.
toluene (20 mL). The solution was heated at 1208C for six days. Volatiles
were removed in vacuo and the residue was washed with hexanes (2ꢂ
5 mL). Yield: 554 mg (95%). X-ray quality crystals were grown from a
layered solution of CH2Cl2/C6H6/pentane. 1H NMR (CD2Cl2): d=7.12–
7.55 (m, 18H), 7.63 (t, 3JHÀH =7 Hz, 1H), 7.74 (t, 3JHÀH =8 Hz, 2H), 7.87
(t, 3JHÀH =7 Hz, 2H), 7.94 ppm (t, 3JHÀH =8 Hz, 2H 19F NMR (CD2Cl2):
[6] a) O. Back, G. Kuchenbeiser, B. Donnadieu, G. Bertrand, Angew.
Chem. Int. Ed. 2009, 48, 5530–5533.; Angew. Chem. 2009, 121,
5638–5641; b) Y. Wang, Y. Xie, P. Wei, R. B. King, H. F. Schaefer
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Angew. Chem. Int. Ed. Engl. 1985, 24, 226–227.
3
d=À127.6 (d, JFÀP =68 Hz, 2F, C6F4), À130.3 (s, 2F, C6F4), À135.4 (m, o-
C6F5), À161.9 (t, 3JFÀF =20 Hz, p-C6F5), À166.9 (m, m-C6F5), À193.1 ppm
(br s, B-F); 31P NMR (CD2Cl2): d=13.3 (tm, 1J PÀP =359 Hz, 1P), À19.3
(ddm, 1JPÀP =359 Hz, 78 Hz, 1P), À28.8 (dd, J=343 Hz, 107 Hz, 1P),
À37.8 ppm (m, 2P); 11B NMR (CD2Cl2): d=À2.7 (d, 1JBÀF =52 Hz). De-
spite repeated attempts, satisfactory elemental analysis data could not be
obtained for this compound. X-ray data: C2/c, a=35.645(4), b=
15.6446(15), c=25.300(3) ꢁ, b=134.5620(10)8, V=10052.2(17) ꢁ3, Z=8,
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1509.
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367–382; c) C. W. Schultz, R. W. Parry, Inorg. Chem. 1976, 15,
3046–3050; d) F. S. Shagvaleev, T. V. Zykova, R. I. Tarasova, T. S.
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R. McDonald, M. J. Ferguson, Inorg. Chem. 2005, 44, 9453–9460;
i) C. A. Dyker, N. Burford, Chem. Asian J. 2008, 3, 28–36; j) C. A.
Dyker, N. Burford, M. D. Lumsden, A. Decken, J. Am. Chem. Soc.
2006, 128, 9632–9633; k) C. A. Dyker, N. Burford, G. Menard,
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l) C. A. Dyker, S. D. Riegel, N. Burford, M. D. Lumsden, A.
data: 8858, parameters: 622, RACTHUNRTGNEUNG(>2s) 0.0765, wR (all) 0.2695, GOF: 1.047.
X-ray data collection and reduction: Crystals were coated in Paratone-N
oil in the glovebox, mounted on a MiTegen Micromount and placed
under an N2 stream, thus maintaining a dry, O2-free environment for
each crystal. The data were collected on a Bruker Apex II diffractometer
with MoKa radiation (l=0.71069 A8). The data were collected at
150(Æ2) K for (1–4), data for 5 was collected at 296 K. The frames were
integrated with the Bruker SAINT software package using a narrow-
frame algorithm. Data were corrected for absorption effects using the
empirical multi-scan method (SADABS).
Structure solution and refinement: Non-hydrogen atomic scattering fac-
tors were taken from the literature tabulations.[24] The heavy atom posi-
tions were determined by using direct methods employing the SHELXTL
direct methods routine. The remaining non-hydrogen atoms were located
from successive difference Fourier map calculations. The refinements
were carried out by using full-matrix least-squares techniques on F, mini-
2
mizing the function w (FoÀFc)2, where the weight w is defined as 4Fo /2s-
2
A
plitudes, respectively. In the final cycles of each refinement, all non-hy-
drogen atoms were assigned anisotropic temperature factors in the ab-
sence of disorder or insufficient data. In the latter cases atoms were treat-
À
ed isotropically. C H atom positions were calculated and allowed to ride
À
on the carbon atom to which they are bonded, assuming a C H bond
length of 0.95 ꢁ. H-atom temperature factors were fixed at 1.10 times
992
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ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2010, 16, 988 – 993

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Received: August 27, 2009
Published online: November 24, 2009
Chem. Eur. J. 2010, 16, 988 – 993
ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
993