Structural features and reactions of a geminal frustrated phosphane/borane Lewis pair

Article abstract of DOI:10.1016/j.jorganchem.2013.06.005

[Bis(pentafluorophenyl)phosphanyl]phenylacetylene (4) undergoes a regioselective hydroboration reaction with HB(C₆F₅)2 to yield the geminal frustrated Lewis pair 5 that bears pairs of strongly electronwithdrawing C₆F₅ substituents at both boron and phosphorus. The X-ray crystal structure analysis has revealed that there is no direct PeB interaction in 5. This has been confirmed by both solid state and solution NMR spectroscopy. The non-interacting geminal FLP 5 undergoes 1,2-P/B addition reactions to carbonyl compounds (benzaldehyde, trans-cinnamic aldehyde), to the C=N bond of phenylisocyanate and to the C=C triple bonds of several alkynes (1-pentyne, phenylacetylene, 4-octyne). The frustrated Lewis pair 5 and several reaction products were characterized by X-ray diffraction.

Full text of DOI:10.1016/j.jorganchem.2013.06.005

Journal of Organometallic Chemistry 744 (2013) 149e155
Contents lists available at SciVerse ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Structural features and reactions of a geminal frustrated
phosphane/borane Lewis pair
Christoph Rosorius, Constantin G. Daniliuc 1, Roland Fröhlich 1, Gerald Kehr,
*
Gerhard Erker
Organisch-Chemisches Institut, Universität Münster, Corrensstrraße 40, 48149 Münster, Germany
a r t i c l e i n f o
a b s t r a c t
Article history:
[Bis(pentafluorophenyl)phosphanyl]phenylacetylene (4) undergoes
a regioselective hydroboration
Received 3 May 2013
Received in revised form
4 June 2013
reaction with HB(C6F5)2 to yield the geminal frustrated Lewis pair 5 that bears pairs of strongly electron-
withdrawing C6F5 substituents at both boron and phosphorus. The X-ray crystal structure analysis has
revealed that there is no direct PeB interaction in 5. This has been confirmed by both solid state and
solution NMR spectroscopy. The “non-interacting” geminal FLP 5 undergoes 1,2-P/B addition reactions to
carbonyl compounds (benzaldehyde, trans-cinnamic aldehyde), to the C]N bond of phenylisocyanate
and to the C^C triple bonds of several alkynes (1-pentyne, phenylacetylene, 4-octyne). The frustrated
Lewis pair 5 and several reaction products were characterized by X-ray diffraction.
Accepted 6 June 2013
Dedicated to Professor Wolfgang
A. Herrmann on the occasion of his 65th
birthday.
Ó 2013 Elsevier B.V. All rights reserved.
Keywords:
Frustrated Lewis pair
Phosphorus
Boron
Molecule activation
1,2-Addition reaction
1. Introduction
is different from many (but not all) “conventional” intramolecular
FLPs. They typically exhibit 11B NMR shifts around
d 60 [8]. Unfor-
Frustrated Lewis pairs (FLPs) feature pairs of non-quenched
Lewis acids (LA) and Lewis bases (LB) in solution that offer the
possibility to undergo synergistic reactions with a variety of added
substrates [1]. The otherwise favoured LA/LB adduct formation in
most FLPs is hindered by the introduction of steric bulk by
attachment of suitable substituents at the components [2].
Recently, there have been reports that the adduct formation can
also effectively be hindered by electronic means [3e5].
The systems 1 to 3 are typical examples. They all contain the
weakly nucleophilic (C6F5)2P phosphanyl group in combination
with the strongly electrophilic (C6F5)2B boryl moiety. Although, the
systems 1 to 3 seem not to be active in heterolytic dihydrogen
splitting, which is a prominent feature of many other FLPs [6], these
systems undergo a variety of typical FLP addition reactions to un-
saturated substrates [6b,7]. From their typical spectroscopic data
the systems 1 to 3 seem not to show a direct PeB interaction, which
tunately all three systems shown in Scheme 1 are difficult to
crystallize. Therefore, to the best of our knowledge no example of
this interesting class of “non-interacting” intramolecular FLPs had
been characterized by X-ray diffraction. We have now prepared a
closely related system, namely the phenyl-substituted FLP 5 and
were able to fully characterize it, including the X-ray crystal
structure analysis. We here report these results together with a few
typical chemical reactions of this example of an “electronically
controlled” intramolecular frustrated Lewis pair.
2. Results and discussion
2.1. Synthesis and characterization of the geminal FLP 5
For this study we reacted phenyl[bis(pentafluorophenyl)phos-
phanyl]acetylene (4) [9] with Piers’ borane [HB(C6F5)2] [10]. The
reaction proceeded rapidly at room temperature in pentane solu-
tion. The hydroboration reaction took place regioselectively and
we eventually isolated the geminal phosphane/borane FLP 5 in 90%
yield (Scheme 2). We obtained single crystals of compound 5 from a
dichloromethane solution at ꢀ34 ꢁC by slow evaporation of the
* Corresponding author. Fax: þ49 251 83 36503.
E-mail address: erker@uni-muenster.de (G. Erker).
1
X-ray crystal structure analysis.
0022-328X/$ e see front matter Ó 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2013.06.005

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C. Rosorius et al. / Journal of Organometallic Chemistry 744 (2013) 149e155
Scheme 1. Geminal FLPs featuring weakly nucleophilic (C6F5)2P groups in combination
with strongly electrophilic (C6F5)2B boryl groups.
solvent. This allowed its characterization by an X-ray crystal
structure analysis.
The structure (see Fig. 1) shows both the (C6F5)2P- and the
(C6F5)2B-substituent in a geminal orientation at the sp2-hybridized
ꢀ
ꢀ
carbon atom C1 of the bridge (P1eC1 1.837(3) A, B1eC1 1.545(3) A,
angle: P1eC1eB1 119.2(3)ꢁ). The P1eB1 separation in compound 5
ꢀ
amounts to 2.921 A. The central C1]C2 carbonecarbon double
bond bears a proton and the phenyl substituent at carbon atom C2
(C1eC2 1.348(4) A, angles: P1eC1eC2 121.8(2)ꢁ, B1eC1eC2
ꢀ
117.1(3)ꢁ, C1eC2eC3 130.0(3)ꢁ). The plane of the phenyl substituent
at C2 is rotated slightly from the olefinic plane (dihedral angle: C1e
C2eC3eC4 36.6ꢁ). The boron atom is planar-tricoordinated (angles:
C1eB1eC31 118.9(3)ꢁ, C1eB1eC41 121.5(3)ꢁ, C31eB1eC41
119.5(3)ꢁ, SBCCC ¼ 359.9ꢁ). Its coordination plane is markedly
rotated out of the plane of the adjacent C1]C2 double bond [6a,11]
(dihedral angles: B1eC1eC2eC3 164.0ꢁ, C31eB1eC1eC2 138.2ꢁ,
C41eB1eC1eC2 39.5ꢁ). Consequently, the B1eC1 bond is only
Fig. 1. Molecular structure of the geminal FLP 5.
(188 K)
¼
8.3
ꢂ
0.2 kcal molꢀ1
;
D
GsrotBC1 (218 K)
¼
9.4 ꢂ 0.2 kcal molꢀ1; for details see the Supporting information].
2.2. Reactions with carbonyl compounds
ꢀ
slightly shorter than the B1eC(aryl) linkages (B1eC31 1.580(5) A,
Compound 5 shows some typical FLP reactions with unsaturated
compounds [7]. It reacts with a variety of carbonyl compounds at
room temperature to yield the respective five-membered zwitter-
ionic heterocycles formed by phosphane/borane addition to the
reactive C]X bond (Scheme 3). The reaction of 5 with phenyl-
isocyanate [13] is a typical example. The reaction was carried out in
pentane at room temperature (12 h) and the resulting precipitate of
the product 6 was then isolated (80% yield). We assume that the P/B
FLP 5 has added to the C]N bond of the isocyanate, similarly as it
had previously been observed for other geminal FLPs [3,4] and
ꢀ
B1eC41 1.582(5) A). The (C6F5)2P-substituent (
q P1eC1eC2eC3
0.7ꢁ) shows a similar conformational orientation, but the phos-
phorus coordination is trigonalepyramidal (angles: C1eP1eC11
105.3(2)ꢁ, C1eP1eC21 104.1(2)ꢁ, C11eP1eC21 96.9(2)ꢁ, SPCCC
¼
ꢁ
ꢀ
306.3 , bond lengths at phosphorus: P1eC1 1.837(3) A, P1eC11
ꢀ
ꢀ
1.849(3) A, P1eC21 1.845(3) A). The C(aryl)eP1eC1eC2 dihedral
angles are C11eP1eC1eC2 153.0ꢁ, C21eP1eC1eC2 51.6ꢁ.
Compound 5 was also characterized by solid state NMR spec-
troscopy [12]. The solid compound 5 features a 11B MAS NMR signal
at diCsSo 57.9 which is in the typical chemical shift range of a strongly
Lewis acidic RB(C6F5)2 moiety. The large quadrupolar coupling
constant and asymmetry parameter close to zero (CQ ¼ 4.2 MHz
and hs ¼ 0.14) indicate a planar-tricoordinate boron geometry and
point to non-interacting Lewis centres. The 31P NMR resonance of 5
related compounds [14]. Consequently, compound 6 shows a 13C
1
NMR carbonyl signal (
d
159.5) that features a large JPC coupling
constant of 118 Hz. The 11B NMR signal occurs at
d
ꢀ4.0 and the 31
P
NMR resonance has been located at
d
ꢀ25.7 (3JPH z 60 Hz). At very
low temperature (193 K) compound 6 shows four separated sets of
19F NMR signals, two of C6F5 groups at phosphorus that show large
Dd19F(p,m) shift differences (C6F5a: 18.3, 20.4, C6Fb5: 18.3, 20.3) and
two at boron that show much smaller Dd19F(p,m) values (C6F5a: 5.8,
6.8, C6Fb5: 7.4, 7.7). The signal of the olefinic ]CH[Ph]moiety of 6
occurs at
d
ꢀ47.4 in the solid state (see Fig. 2).
In solution compound 5 shows a 11B NMR resonance at
d 59.3
and a 31P NMR signal at
d
ꢀ48.2. The 13C NMR signals of the
bridging C]CHPh moiety occur at d 143.0 (C1) and d 158.1 []C(2)H,
2JPC ¼ 8.8 Hz, corresponding 1H NMR signal at
d
7.86, JPH
¼
3
occurs at
d
8.05 (3JPH ¼ 60.6 Hz).
20.0 Hz]. The 19F NMR spectrum shows two sets of C6F5 signals, one
of the P(C6F5)2 and one of the B(C6F5)2 groups. Both feature very
large Dd19F(p,m) shift differences (11.4, 13.8) as it is e.g. typical for
strongly Lewis acidic tricoordinated RB(C6F5)2 units [12]. At very
low temperature (CD2Cl2, 173 K) the C6F5 substituent pairs at both
phosphorus and boron are chemically inequivalent, indicating
We next reacted the geminal FLP 5 with benzaldehyde. Clean
1,2-P/B addition to the carbonyl group was observed. We isolated
the zwitterionic five-membered heterocyclic product 7 in >50%
yield. In solution compound 7 shows the typical 1H NMR signal of
the olefin proton at the bridge {]CH[Ph]:
d
8.53 (3JPH ¼ 62.8 Hz)}
and the 1H NMR doublet of the former benzaldehyde eCH[O]
hindered rotation around the heteroatom-C1 vectors. Increasing
proton (
d
6.19, 2JPH ¼ 14.9 Hz). The 11B NMR signal of 7 is at
d 0.7 and
s
D
the temperature results in coalescence of each pair [ GrotPC1
the 31P NMR resonance at
d
ꢀ2.2. At 233 K compound 7 shows four
well separated sets of 19F NMR signals of the pair of C6F5 groups at
phosphorus [Dd19F(p,m) ¼ 16.6, 17.7 (C6F5a), 18.0, 21.0 (C6Fb5)] and at
boron [Dd19F(p,m) ¼ 5.8 (C6Fa5), 4.9 (C6Fb5)].
Compound 7 was characterized by X-ray diffraction (single
crystals were obtained by slow solvent evaporation from
a
dichloromethane solution at low temperature). The X-ray crystal
structure analysis showed that a five-membered heterocyclic core
ꢀ
structure had been formed with bond lengths of P1eC1 1.781(2) A,
ꢀ
ꢀ
ꢀ
Scheme 2. Synthesis of the geminal FLP 5.
C1eB11.662(4) A, B1eO11.507(3) A, O1eC9 1.389(3) A, and C9eP1

C. Rosorius et al. / Journal of Organometallic Chemistry 744 (2013) 149e155
151
Fig. 2. Left: 11B{1H} MAS NMR spectrum of compound 5 (vrot ¼ 14.0 kHz, 11.74 T), (a) and corresponding line shape simulation (b) based on the quadrupolar coupling parameters
mentioned in the text and the following 11B chemical shielding anisotropy parameters: Ds ¼ 91.3 ppm and hs ¼ 0.16. Right: 31P{1H} CPMAS NMR spectrum of 5 (vrot ¼ 10.0 kHz,
7.05 T). * marks spinning sidebands and þ an impurity.
ꢀ
1.896(3) A. The internal bond angles inside the five-membered ring
amount to P1eC1eB1 104.1(2)ꢁ, C1eB1eO1 104.4(2)ꢁ, B1eO1eC9
112.5(2)ꢁ, O1eC9eP1 97.2(2)ꢁ and C9eP1eC1 93.0(1)ꢁ. Carbon
atom C1 is planar-tricoordinate (SC1PCB 359.3ꢁ) (Fig. 3). In solution
compound 7 shows dynamic 19F NMR spectra, indicating reversible
P1eC9 bond dissociation with an estimated Gibbs activation energy
2.3. Reactions of the FLP 5 with alkynes
Many frustrated Lewis pairs typically undergo addition re-
actions to alkynes [3e5,15] and so does the FLP 5 (Scheme 4). The
geminal FLP 5 reacted cleanly with e.g. 1-pentyne at room tem-
perature. The reaction proceeded chemo- and regioselectively to
give the 1,2-addition product 9. It was isolated in 53% yield. The X-
ray crystal structure analysis showed that the borane Lewis acid of
of
D
Gsdiss (343 K) ¼ 15.0 ꢂ 0.2 kcal molꢀ1 (for details see the
Supporting information).
ꢀ
We have also reacted the FLP 5 with trans-cinnamic aldehyde.
The addition product 8 was isolated in ca. 50% yield. The NMR
analysis showed that selective P/B addition to the aldehyde
carbonyl group had taken place. We have observed the typical NMR
resonances of the remaining trans [Ph]eCH]CH double bond [1H:
5 had added to the alkyne terminus (B1eC10 1.621(3) A) and the
phosphane Lewis base has become attached to the adjacent former
ꢀ
ꢀ
acetylene carbon (P1eC9 1.789(2) A, C9eC10 1.336(3) A). The
remaining structural features of the zwitterionic five-membered
heterocyclic phosphonium/borate product are in the expected
6.79, 6.23, 13C:
to signals at
5.83 (1H) and
C]CH[Ph] moiety features resonances at
13C, ]CHe) and 137.1 (PCB), respectively. The 11B NMR resonance
of compound 8 was found at
0.9 and the 31P NMR signal at
d
135.6, 120.1]. The adjacent CH[O] group gives rise
83.8 (13C), respectively. The bridging
8.49 (1H) and
159.3
range (P1eC1 1.779(2) A, C1eB1 1.664(3) A, C1eC2 1.336(3) A, see
Fig. 4).
ꢀ
ꢀ
ꢀ
d
d
d
d
d
In solution compound 9 shows the 13C NMR signals of the C1
(
d
bridge at
d
135.4 (C1) and
d
157.2 [C(2)H, 1H: 8.16 (3JPH ¼ 62.5 Hz)],
d
d
ꢀ3.2.
respectively. The corresponding 13C/1H NMR signals of the newly
Compound 8 also exhibits temperature dependent dynamic 19F
NMR spectra. We monitored two dynamic processes. At very low
temperature (<253 K) the PeC6F5 rotations seem to be frozen on
the 19F NMR time scale. At higher temperature we saw pairwise
coalescence of the o-, p- and m-C6F5 signals of the B(C6F5)2 and the
p-C6F5 signals of the P(C6F5)2 moieties which indicates reversible
formed C2-bridge were located at d
178.9 [C(10)H, 1H: 8.07,
3JPH ¼ 61.3 Hz] and
d
127.8 (C9, 1JPC ¼ 86.8 Hz). Compound 9 exhibits
the heteronucleic NMR resonances at
d
ꢀ2.0 (31P) and
d
ꢀ9.7 (11B)
with the latter signal showing coupling to the phosphorus nucleus
(JPB z 38 Hz) [16]. The FLP 5 reacts analogously with phenyl-
acetylene to form the corresponding 1,2-P/B addition product 10.
P1eC9 bond breaking in compound
8
[3,5]
[
D
Gsdiss
It shows the 31P NMR signal at
d 1.4 as a partly relaxed 1:1:1:1
(308 K) ¼ 13.7 ꢂ 0.2 kcal molꢀ1; for details see the Supporting
quartet due to coupling with the boron nucleus [11B:
d
ꢀ9.7 (d,
information].
JPB z 40 Hz)]. The 13C/1H NMR C(3)H signal of the newly formed
Ph
Ph
H
Ph
H
O
C
N
(C6F5)2P
B(C6F5)2
(C6F5)2P
O
B(C6F5)2
N
5
Ph
CHO
6
Ph
Ph-CHO
Ph
H
Ph
H
(C6F5)2P
B(C6F5)2
(C6F5)2P
B(C6F5)2
O
O
H
H
Ph
8
7
Ph
Scheme 3. Reactivity of the FLP 5 towards several carbonyl compounds.
Fig. 3. Molecular structure of compound 7.

152
C. Rosorius et al. / Journal of Organometallic Chemistry 744 (2013) 149e155
boron centre is planar tricoordinate. Solid state NMR spectroscopy
is a very well suited spectroscopic technique to characterize typical
FLP features [12]. The FLP 5 undergoes a variety of synergistic P/B
addition reactions to unsaturated organic substrates. It is well
known that a variety of P/B [15] (or N/B) [18] FLPs react with ter-
minal alkynes by competing reaction pathways, namely CeH
deprotonation and 1,2-P/B addition to the alkyne C^C triple bond.
The P(C6F5)2 group in 5 is apparently not sufficiently basic enough
to deprotonate the terminal alkynes used in our study. Therefore,
we have observed selective 1,2-addition to the acetylenic sub-
strates. This study has served to further characterize the spectral
features exhibited by the P(C6F5)2 containing geminal FLPs. It shows
that in some cases FLP behaviour can be governed to quite some
extend by electronic features of the substituents at their Lewis acid
and basic compounds, in addition to the ubiquitous steric control
for which FLPs are well known.
4. Experimental
Fig. 4. A view of the molecular structure of compound 9.
4.1. General
All experiments were carried out under a dry argon atmosphere
using standard Schlenk techniques or in a glove box. Solvents
(including deuterated solvents used for NMR) were dried and
distilled prior to use. 1H, 13C, 11B, 19F, 31P NMR spectra were recorded
on a Varian 500 MHz INOVA or a Varian 600 MHz UNITY plus NMR
spectrometer at ambient temperature unless otherwise stated.
Chemical shifts are given in ppm relative to solvents (1H and 13C) or
an external standard [
d
(BF3$OEt2) ¼ 0 for 11B NMR,
(CFCl3) ¼ 0 for
d
19F NMR and
d
(85% H3PO4) ¼ 0 for 31P NMR]. Coupling constants are
in Hz. Elemental analysis data were recorded on Foss-Heraeus
CHNO-Rapid. B(C6F5)3 [23] (caution: the intermediate involved is
explosive), HB(C6F5)2 [10], and (C6F5)2PCl [9b] were prepared
according to procedures reported in the literature. X-Ray diffrac-
tion: Data sets were collected with a Nonius KappaCCD diffrac-
tometer. Programs used: data collection, COLLECT (R. W. W. Hooft,
Bruker AXS, 2008, Delft, The Netherlands); data reduction Denzo-
SMN [19]; absorption correction, Denzo [20]; structure solution
SHELXS-97 [21]; structure refinement SHELXL-97 [22] and
graphics, XP (BrukerAXS, 2000). Thermals ellipsoids are shown
with 30% probability, R-values are given for observed reflections,
and wR2 values are given for all reflections. Exceptions and special
features: Compounds 5 and 7 crystallized with one dichloro-
methane molecule disordered over two positions in the asym-
metric unit. Several restraints (ISOR, SIMU and SAME) were used in
order to improve refinement stability. The five membered hetero-
cyclic ring and one dichloromethane molecule in compound 10 are
disordered over two positions. Several restraints (SIMU, SAME,
SADI and EADP) were used in order to improve refinement stability.
Scheme 4. Reactivity of the FLP 5 towards terminal and internal alkynes.
vicinal bridge of compound 10 occurs at
d d 8.35 (d,
183.8 [1H:
3JPH ¼ 57.2 Hz)]. We have monitored two equal intensity sets of 19
F
NMR resonances. The P(C6F5)2 signals show a large Dd19F(p,m) value
of 16.7 whereas the B(C6F5)2 signals exhibit a typical small “borate
anion” Dd19F(p,m) chemical shift separation of 4.5. Compound 10
was also characterized by X-ray diffraction. It shows similar struc-
tural features as compound 9 (for details see the Supporting
information).
The FLP 5 was also added to an internal alkyne. Its reaction with
4-octyne gave the product 11 that was isolated in 48% yield as a
white solid material. It shows the typical 31P (
d
2.4) and 11B [
d
ꢀ8.6
4.2. Preparation of compound 4
(JPB z 35 Hz)] NMR chemical shifts of this geminal class of com-
pounds and 13C NMR signals of
d
197.8 and
d
121.5 (d, 1JPC ¼ 93.3 Hz)
A solution of bis(pentafluorophenyl)chlorophosphane (7.48 g,
18.5 mmol, 1.0 eq) in n-pentane (6 mL) was added to a suspension
of lithium phenylacetylenide (2.0 g, 18.5 mmol, 1.0 eq) in dry thf
(80 mL) at 0 ꢁC. The resulting orange to brown mixture was warmed
up to room temperature and stirred for 4 h. The solvent of the
resulting brown solution was removed in vacuo and the orangeered
residue was dissolved in n-pentane (80 mL) before filtration over
silica gel to remove the formed lithium chloride. Compound 4 was
then precipitated at ꢀ30 ꢁC as colourless crystals (3.93 g, 8.4 mmol,
45%). Anal. Calcd. for C20H5F10P: C, 51.52; H, 1.08. Found: C, 51.60; H,
of the vicinal C]C bridge. The P(C6F5)2 19F NMR signals occur at
d
ꢀ127.2 (o), ꢀ142.0 (p) and ꢀ158.1 (m), those of the B(C6F5)2 unit at
d
ꢀ130.6 (o), ꢀ160.6 (p) and ꢀ165.5 (m).
3. Conclusions
To the best of our knowledge compound 5 is the first geminal P/
B FLP featuring the weakly basic P(C6F5)2 group that was charac-
terized by X-ray diffraction [17]. This revealed that in 5 the Lewis
acid and the Lewis base have no direct interaction. The separation
1.19. Mp: 102 ꢁC (DSC). IR (KBr)
(600 MHz, CD2Cl2, 298 K):
n
(C^C)/cmꢀ1 ¼ 2173 (m). 1H NMR
ꢀ
of the P and B atoms in 5 amounts to 2.921 A and the conforma-
d
¼ 7.52 (m, 2H, o-Ph), 7.43 (m, 1H, p-Ph),
tional arrangement prohibits any developing PeB contact. The
7.38 (m, 2H, m-Ph). 13C{1H} NMR (151 MHz, CD2Cl2, 298 K):

C. Rosorius et al. / Journal of Organometallic Chemistry 744 (2013) 149e155
153
1
1
d
¼ 148.0 (d, JFC w 251 Hz, C6F5), 143.4 (d, JFC w 256 Hz, C6F5),
NMR (151 MHz, CD2Cl2, 299 K):
d
¼ 159.5 (d, 1JPC ¼ 117.6 Hz, C]O),
138.2 (d, 1JFC w 254 Hz, C6F5), 132.3 (d, 4JPC ¼ 2.3 Hz, o-Ph), 130.4 (p-
155.6 (d, 2JPC ¼ 5.3 Hz, ]CH),141.1 (d, 3JPC ¼ 11.7 Hz, i-PhB), 136.6 (d,
3JPC ¼ 14.4 Hz, i-PhA), 130.8 (p-PhA), 128.9 (m-PhA), 128.8 (o-PhB),
128.0 (o-PhA), 127.0 (p-PhB),126.3 (br, PCB)a, 124.8 (m-PhB), 118.7 (br,
3
Ph), 128.9 (m-Ph), 121.8 (d, JPC
¼
1.4 Hz, i-Ph), 109.9 (d,
2JPC ¼ 14.5 Hz, ^C-Ph), 107.8 (m, i-C6F5), 77.4 (m, PeC^). 19F NMR
i-C6FB5), 94.8 (dm, JPC ¼ 78.7 Hz, i-C6F5P) [C6F5: not listed, from
1
a
(564 MHz, CD2Cl2, 298 K):
d
¼ ꢀ130.3 (2F, o), ꢀ150.0 (1F, p), ꢀ161.0
(2F, m) (each m) [Ddpm ¼ 11.0]. 31P{1H} NMR (243 MHz, CD2Cl2,
GHMBC experiment]. 11B{1H} NMR (192 MHz, CD2Cl2, 299 K):
3
298 K):
d
¼ ꢀ82.3 (quin, JPF ¼ 31.6 Hz).
d
¼ ꢀ4.0 (n1/2 w80 Hz). 19F NMR (564 MHz, CD2Cl2, 298 K):
¼ ꢀ125.2 (br, 2F, o), ꢀ137.6 (m, 1F, p), ꢀ156.4 (m, 2F, m) (PC6F5)
d
4.3. Preparation of compound 5
[
Ddpm ¼ 18.8], ꢀ132.2 (br, 2F, o), ꢀ157.6 (m, 1F, p), ꢀ164.5 (m, 2F, m)
(BC6F5) [Ddpm ¼ 6.9]. 31P NMR (243 MHz, CD2Cl2, 299 K):
d
¼ ꢀ25.7
3
Compound 4 (3.00 g, 6.43 mmol, 1.0 eq) was added to a sus-
pension of bis(pentafluorophenyl)borane (2.22 g, 6.43 mmol,
1.0 eq) in n-pentane (80 mL) at 0 ꢁC. Upon warming up to room
temperature and stirring for 2 h the colour of the solution turned
from orange to yellow. The solvent was removed in vacuo and
product 5 was obtained as a bright yellow solid (4.71 g, 5.79 mmol,
90%). Crystals suitable for the X-ray crystal structure analysis were
obtained by slow evaporation of a saturated solution of 5 in
dichloromethane at ꢀ34 ꢁC. Anal. Calcd. for C32H6BF20P: C, 47.32; H,
0.74. Found: C 48.13, H 1.07. Mp: 131 ꢁC (DSC). 1H NMR (500 MHz,
(dm, JPH w 60 Hz). 31P{1H} NMR (243 MHz, CD2Cl2, 299 K):
d
¼ ꢀ25.7 (n1/2 w40 Hz).
4.4.3. Preparation of compound 7
Compound 5 (200 mg, 0.246 mmol, 1 eq) was reacted with
benzaldehyde (26 mg, 0.246 mmol, 1 eq) to yield 7 as a white solid
(115 mg, 0.125 mmol, 51%). Crystals suitable for the X-ray crystal
structure analysis were obtained by slow evaporation of a saturated
solution of 7 in dichloromethane at ꢀ34 ꢁC. Anal. Calcd. for
C39H12BF20OP: C, 51.01; H 1.32. Found: C, 51.16; H, 1.48. Mp: 178 ꢁC
CD2Cl2, 299 K):
d
¼ 7.86 (d, 3JPH ¼ 20.0 Hz, 1H, ]CH), 7.38 (m, 2H, o-
(DSC). 1H NMR (600 MHz, CD2Cl2, 299 K):
d
¼ 8.53 (d, 3JPH ¼ 62.8 Hz,
Ph), 7.27 (m, 2H, m-Ph), 7.25 (m, 1H, p-Ph). 13C{1H} NMR (126 MHz,
1H, ]CH), 7.37 (m, 1H, p-PhB), 7.27 (m, 2H, m-PhB), 7.23 (m, 1H, p-
PhA), 7.17 (m, 2H, m PhA), 7.15 (m, 2H, o-PhB), 7.04 (m, 2H, o-PhA),
CD2Cl2, 299 K):
d
¼ 158.1 (d, 2JPC ¼ 8.8 Hz, ]CH), 143.0 (m br, PCB)a,
2
137.0 (i-Ph), 130.3 (d, J ¼ 1.1 Hz, p-Ph), 128.9 (m-Ph), 128.4 (d,
6.19 (d, JPH ¼ 14.9 Hz, 1H, OCH). 13C{1H} NMR (151 MHz, CD2Cl2,
4JPC ¼ 6.1 Hz, o-Ph), [C6F5 not listed, a from GHMBC experiment]. 11
B
299 K):
d
¼ 159.4 (]CH), 139.5 (d, JPC ¼ 13.5 Hz, i-PhA), 137.4 (br,
3
{1H} NMR (160 MHz, CD2Cl2, 299 K):
d
¼ 59.3 (br, n1/2 w1500 Hz).
PCB)a, 133.4 (m, i-PhB), 130.5 (d, 5JPC ¼ 4.7 Hz, p-PhB), 129.5 (p-PhA),
129.0 (d, 4JPC ¼ 3.7 Hz, m-PhB),128.9 (m-PhA),126.69 (o-PhA),126.61
11B{1H} MAS (nrot ¼ 14 kHz, 11.74 T):
d
¼ 57.9 (CQ ¼ 4.23 MHz,
3
1
h
¼ 0.14). 19F NMR (470 MHz, CD2Cl2, 299 K):
d
¼ ꢀ127.1 (br, 2F,
(d, JPC ¼ 5.4 Hz, o-PhB), 85.4 (d, JPC ¼ 47.5 Hz, OCH) [C6F5: not
o), ꢀ149.6 (m, 1F, p), ꢀ161.0 (m, 2F, m) (PC6F5) [Ddpm ¼ 11.4], ꢀ128.1
(2F, o), ꢀ147.0 (1F, p), ꢀ160.8 (2F, m) (each m, BC6F5) [Ddpm ¼ 13.8].
listed, a from GHMBC experiment]. 11B{1H} NMR (192 MHz, CD2Cl2,
299 K):
d
¼ 0.7 (n1/2 w80 Hz). 19F NMR (470 MHz, CD2Cl2, 299 K):
31P{1H} NMR (202 MHz, CD2Cl2, 299 K):
d
¼ ꢀ48.2 (m). 31P{1H}
d
¼ ꢀ124.1, ꢀ125.7 (each br, each 2F, each o), ꢀ139.3, ꢀ140.2 (each
CPMAS (nrot ¼ 10 kHz, 7.05 T):
d
¼ ꢀ47.4.
m, each 1F, each p), ꢀ157.0 (m), ꢀ158.4 (br) (each 2F, each m,
X-ray crystal structure analysis of compound 5: Formula
C32H6BF20P ꢃ CH2Cl2, M ¼ 897.07, yellow crystal, 0.24 ꢃ 0.12 ꢃ
PC6F5), ꢀ132.0 (m, 2F, o), ꢀ159.3 (t, 3JFF ¼ 19.8 Hz, 1F, p), ꢀ165.1 (m,
2F, m) (BC6Fa5) [Dd
F
pm
¼ 5.8], ꢀ135.2 (m, 2F, o), ꢀ160.6 (t,
19
19
0.12 mm, a ¼ 11.2024(5), b ¼ 12.4598(3)ꢁ, c ¼ 14.3586(11) A,
3JFF ¼ 19.7 Hz, 1F, p), ꢀ165.6 (m, 2F, m) (BC6Fb5) [Dd
F
¼ 5.0]. 31
P
ꢀ
pm
3
ꢀ
3
a
¼ 68.421(3),
b
¼ 85.294(4),
g
¼ 63.618(3) , V ¼ 1661.61(15) A ,
NMR (243 MHz, CD2Cl2, 299 K): d
¼ ꢀ2.2 (dm, JPH w 63 Hz). 31P
rcalc ¼ 1.793 g cmꢀ3
,
m
¼ 3.531 mmꢀ1, empirical absorption
{1H} NMR (243 MHz, CD2Cl2, 299 K):
d
¼ ꢀ2.2 (n1/2 w50 Hz).
correction (0.484 ꢄ T ꢄ 0.676), Z ¼ 2, triclinic, space group P1 (No.
X-ray crystal structure analysis of compound 7: Formula
C39H12BF20OP ꢃ CH2Cl2, M ¼ 1003.19, colourless crystal, 0.35 ꢃ
ꢀ
2),
l
¼ 1.54178 A, T ¼ 223(2) K,
u and 4 scans, 18934 reflections
] ¼ 0.60 Åꢀ1, 5657 independent
0.32 ꢃ 0.10 mm, a ¼ 11.4027(4), b ¼ 21.0993(5), c ¼ 16.1444(3) A,
ꢀ
collected (ꢂh, ꢂk, ꢂl), [(sin
q)/l
(Rint ¼ 0.059) and 4742 observed reflections [I > 2
s
(I)], 542 refined
b
¼ 96.181(2) , V ¼ 3861.58(18) A , rcalc ¼ 1.726 g cmꢀ3
,
m
¼
3
ꢀ
ꢁ
parameters, R ¼ 0.057, wR2 ¼ 0.171, max. (min.) residual electron
3.136 mmꢀ1, empirical absorption correction (0.406 ꢄ T ꢄ 0.744,
ꢀꢀ3
ꢀ
density 0.50 (ꢀ0.41) e.A , hydrogen atoms were calculated and
Z ¼ 4), monoclinic, space group P21/n (No. 14),
l
¼ 1.54178 A,
refined as riding atoms.
T ¼ 223(2) K,
u
and 4 scans, 37748 reflections collected (ꢂh, ꢂk, ꢂl),
[(sin )/
q
l
] ¼ 0.60 Åꢀ1, 6708 independent (Rint ¼ 0.044) and 6116
4.4. Reaction of 5 with small molecules
observed reflections [I > 2
s
(I)], 614 refined parameters, R ¼ 0.048,
wR2
¼
0.124, max. (min.) residual electron density 0.51
ꢀꢀ3
4.4.1. General procedure
(ꢀ0.39) e A , hydrogen atoms were calculated and refined as
Compound 5 was dissolved in n-pentane (5 mL) and then
treated with a solution of the respective substrate (1 eq) in n-
pentane (2e3 mL) at room temperature. Upon stirring the reaction
mixture for 12 h at room temperature the resulting precipitate was
collected and washed with n-pentane (3 ꢃ 4e8 mL). Subsequently
the obtained solid was dried in vacuo to get the respective product.
riding atoms.
4.4.4. Preparation of compound 8
Compound 5 (200 mg, 0.25 mmol, 1.0 eq) was reacted with
cinnamic aldehyde (33 mg, 0.25 mmol, 1.0 eq) to give 8 as a white
solid (115 mg, 0.125 mmol, 51%). Elemental Analysis: calcd. for
C41H14BF20OP: C, 52.15; H, 1.49. Found: C, 52.31; H, 1.72. Dp: 182 ꢁC
4.4.2. Preparation of compound 6
(DSC). 1H NMR (600 MHz, CD2Cl2, 299 K):
d
¼
8.49 (d,
Caution: Many isocyanates are toxic and must be handled with
due care. Compound 5 (200 mg, 0.25 mmol, 1.0 eq) was reacted
with phenylisocyanate (29 mg, 0.25 mmol, 1.0 eq) to give 6 as a
white solid (183 mg, 0.197 mmol, 80%). Anal. Calcd. for
C39H11BF20NOP: C, 50.30; H, 1.19; N,1.50. Found: C, 50.25; H, 1.41; N,
3JPH ¼ 63.0 Hz, 1H, ]CH), 7.33 (m, 2H, m-PhB)a, 7.31 (m,
1H, p-PhB)a, 7.28 (br, 2H, o-PhB), 7.24 (m, 1H, p-PhA), 7.19 (m,
2H, m-PhA), 7.07 (m, 2H, o-PhA), 6.79 (m, 1H, ]CHPh)t, 6.23 (m,
1H,]CHCH)t, 5.83 (m, 1H, OCH) [a from GHMBC and GHSQC
t
experiment,
tentative assignment]. 13C{1H} NMR (151 MHz,
d
1.24. Dp: 178 ꢁC (DSC). 1H NMR (600 MHz, CD2Cl2, 299 K):
d
¼ 8.05
CD2Cl2, 299 K):
¼ 159.3 (br, ]CH), 139.4 (d, 3JPC ¼ 14.0 Hz, i-PhA),
(d, JPH ¼ 60.6 Hz, 1H, ]CH), 7.29 (m, 1H, p-PhA)a, 7.25 (m, 2H, m-
137.1 (br, PCB)a, 135.6 (br, ]CHPh a t, 135.5 (br, i-PhB), 129.6 (p-PhA),
)
3
PhA)a, 7.21 (m, 2H, m-PhB)a, 7.20 (m, 2H, o-PhB)a, 7.18 (m, 2H, o-
129.3 (br, p-PhB), 129.2 (m-PhB), 128.9 (m-PhA), 127.0 (br, o-PhB),
126.8 (d, 4JPC ¼ 2.0 Hz, o-PhA), 120.1 (br, ]CHCH)t, 96.8 (br, i-C6F5),
PhA)a, 7.09 (m, 1H, p-PhB)a
[
from GHSQC experiment]. 13C{1H}
a

154
C. Rosorius et al. / Journal of Organometallic Chemistry 744 (2013) 149e155
1
a
83.8 (dm, JPCt w 45 Hz, OCH) [C6F5: not listed, from GHMBC
X-ray crystal structure analysis of compound 10: formula
experiment,
CD2Cl2, 299 K):
C2D2Cl4, 348 K):
tentative assignment]. 11B{1H} NMR (192 MHz,
C
40H12BF20P ꢃ CH2Cl2, M ¼ 999.20, colourless crystal, 0.40 ꢃ
¼ 0.9 (s, n1/2 w170 Hz). 19F NMR (564 MHz,
¼ ꢀ126.9 (br, 2F, o), ꢀ141.4 (br, 1F, p), ꢀ158.8 (m,
0.35 ꢃ 0.35 mm, a ¼ 10.7892(1), b ¼ 19.7180(3), c ¼ 18.2863(2) A,
ꢀ
d
3
¼ 95.296(1) , V ¼ 3873.65(8) A , rcalc ¼ 1.713 g cmꢀ3
,
m
¼
ꢁ
ꢀ
d
b
2F, m) (PC6F5) [Ddpm ¼ 17.4], ꢀ135.1 (2F, o), ꢀ160.4 (1F, p), ꢀ166.2
0.339 mmꢀ1, empirical absorption correction (0.876 ꢄ T ꢄ 0.890,
(2F, m) (each br, BC6F5) [Ddpm ¼ 5.8]. 31P{1H} NMR (243 MHz,
Z ¼ 4), monoclinic, space group P21/n (No. 14),
l
¼ 0.71073 A,
ꢀ
CD2Cl2, 299 K):
d
¼ ꢀ3.2 (dm, J w 58 Hz).
T ¼ 223(2) K,
ꢂl), [(sin )/
u
and 4 scans, 30627 reflections collected (ꢂh, ꢂk,
q
l
] ¼ 0.60 Åꢀ1, 6697 independent (Rint ¼ 0.036) and 5652
4.4.5. Preparation of compound 9
observed reflections [I > 2
s
(I)], 627 refined parameters, R ¼ 0.069,
Compound 5 (200 mg, 0.246 mmol, 1 eq) was reacted with 1-
pentyne (17 mg, 0.246 mmol, 1 eq) to yield 9 as a white solid
(114 mg, 0.130 mmol, 53%). Crystals suitable for the X-ray crystal
structure analysis were obtained by slow evaporation of a saturated
solution of 9 in dichloromethane at ꢀ34 ꢁC. Anal. Calcd. for
C37H14BF20P: C, 50.48; H, 1.60. Found: C, 50.34; H, 1.78. Mp: 212 ꢁC
wR2
¼
0.173, max. (min.) residual electron density 0.51
ꢀꢀ3
(ꢀ0.49) e A , hydrogen atoms were calculated and refined as
riding atoms.
4.4.7. Preparation of compound 11
Compound 5 (200 mg, 0.25 mmol, 1.0 eq) and 4-octyne (20 mg,
0.25 mmol,1.0 eq) were dissolved in toluene (5 mL) and stirred for 7
days at 70 ꢁC. Subsequently, the solvent was removed in vacuo and
the residue was mixed with n-pentane. The resulting white pre-
cipitate was collected from the suspension and washed with n-
pentane (3 ꢃ 5 mL) to yield 11 as a white solid (108 mg, 0.12 mmol,
48%). Anal. Calcd. for C40H20BF20P: C, 52.09; H, 2.19. Found: C, 52.62;
H, 2.13. Mp: 220 ꢁC (DSC). 1H NMR (600 MHz, CD2Cl2, 299 K):
(DSC). 1H NMR (600 MHz, CD2Cl2, 299 K):
d
¼ 8.16 (d, 3JPH ¼ 62.5 Hz,
1H, ]CH), 8.07 (d, 3JPH ¼ 61.3 Hz, 1H, ]CHB), 7.23 (m, 1H, p-Ph), 7.16
(m, 2H, m-Ph), 6.94 (m, 2H, o-Ph), 2.19 (m, 2H, ]CH2), 1.61 (m, 2H,
CH2), 0.90 (tm, JHH ¼ 7.3 Hz, 3H, CH3). 13C{1H} NMR (151 MHz,
3
CD2Cl2, 299 K):
d
¼ 178.9 (m, ]CHB), 157.2 (]CH), 138.8 (d,
3JPC ¼ 14.0 Hz, i-Ph), 135.4 (m br, PCB), 129.2 (p-Ph), 128.9 (m-Ph),
127.8 (d, 1JPC ¼ 86.8 Hz, PC]), 126.8 (d, J ¼ 1.9 Hz, o-Ph), 122.4 (br, i-
1
2
C6FB5), 100.3 (dtm, JPC ¼ 71.4 Hz, JFC ¼ 16.8 Hz, i-C6FP5), 31.8 (d,
d
¼ 7.95 (d, 3JPH ¼ 61.8 Hz, 1H, ]CH), 7.20 (m, 1H, p-Ph), 7.13 (m, 2H,
2JPC ¼ 15.9 Hz, ]CH2), 21.4 (d, 3JPC ¼ 7.4 Hz, CH2), 13.7 (CH3) [C6F5:
m-Ph), 6.89 (m, 2H, o-Ph), 2.47 (m, 2H, BCH2), 2.35 (m, 2H, PCH2),
not listed]. 11B{1H} NMR (192 MHz, CD2Cl2, 299 K):
d
¼ ꢀ9.7 (d,
1.32 (m, 2H, PCH2), 0.99 (m, 2H, BCH2), 0.89 (t, 3JHH ¼ 7.4 Hz, PCH3),
JPB w 38 Hz). 19F NMR (564 MHz, CD2Cl2, 299 K):
d
¼ ꢀ127.3 (2F,
0.78 (t, JHH ¼ 7.4 Hz, 3H, BCH3). 13C{1H} NMR (151 MHz, CD2Cl2,
3
o), ꢀ141.5 (1F, p), ꢀ157.8 (2F, m) (each m, PC6F5)
299 K):
d
¼ 197.8 (m br, BC]), 153.6 (]CH), 138.6 (i-Ph), 135.4 (br,
[
Dd F
pm
¼ 16.3], ꢀ132.0 (m, 2F, o), ꢀ161.0 (t, JFF ¼ 20.3 Hz, 1F,
PCB), 128.9 (p-Ph), 128.7 (m-Ph), 126.9 (o-Ph), 122.5 (m br, i-C6FB5),
121.5 (d, 1JPC ¼ 93.3 Hz, PC]), 100.9 (dm, 1JPC ¼ 69.2 Hz, i-C6FP5), 37.6
(d, JPC ¼ 20.0 Hz, BCH2), 30.2 (d, JPC ¼ 16.2 Hz, PCH2), 22.1 (PCH2),
21.6 (BCH2), 15.3 (BCH3), 14.6 (PCH3) [C6F5: not listed]. 11B{1H} NMR
19
3
19
p), ꢀ165.5 (m, 2F, m) (BC6F5) [Dd
F
pm
¼ 4.5]. 31P{1H} NMR (243 MHz,
CD2Cl2, 299 K):
d
¼ ꢀ2.0 (m, partially relaxed JPB w 40 Hz).
X-ray crystal structure analysis of compound 9: formula
C37H14BF20P, M ¼ 880.26, colourless crystal, 0.20 ꢃ 0.20 ꢃ 0.09 mm,
(192 MHz, CD2Cl2, 299 K):
(564 MHz, CD2Cl2, 299 K):
d
¼ ꢀ8.6 (d, JPB w 35 Hz). 19F NMR
¼ 98.856(2)ꢁ,
d
¼ ꢀ127.2 (br, 2F, o), ꢀ142.0 (m, 1F,
ꢀ
a ¼ 11.0902(4), b ¼ 12.9944(3), c ¼ 24.2301(8) A,
b
V ¼ 3450.18(19) A , rcalc ¼ 1.695 g cmꢀ3
,
m
¼ 1.996 mmꢀ1, empirical
p), ꢀ158.1 (m, 2F, m) (PC6F5) [Dd
F
pm
¼ 16.1], ꢀ130.6 (br, 2F,
3
ꢀ
19
3
absorption correction (0.690 ꢄ T ꢄ 0.840, Z ¼ 4), monoclinic, space
o), ꢀ160.6 (t, JFF ¼ 20.2 Hz, 1F, p), ꢀ165.5 (m, 2F, m) (BC6F5)
19
ꢀ
group P21/c (No. 14),
30484 reflections collected (ꢂh, ꢂk, ꢂl), [(sin
l
¼ 1.54178 A, T ¼ 223(2) K,
u
and 4 scans,
[
Dd
F
pm
¼ 4.8]. 31P{1H} NMR (243 MHz, CD2Cl2, 299 K):
d
¼ 2.4
q)/
l
] ¼ 0.60 Åꢀ1, 5985
(partially relaxed JPB w 40 Hz).
independent (Rint
¼
0.045) and 5216 observed reflections
[I > 2
s
(I)], 533 refined parameters, R ¼ 0.043, wR2 ¼ 0.115, max.
Acknowledgements
ꢀꢀ3
(min.) residual electron density 0.30 (ꢀ0.30) e A , hydrogen atoms
were calculated and refined as riding atoms.
Financial Support from the Deutsche Forschungsgemeinschaft
is gratefully acknowledged. We thank Dipl. Chem. T. Wiegand
and Prof. Dr. H. Eckert for carrying out the solid state NMR
measurements.
4.4.6. Preparation of compound 10
Compound 5 (200 mg, 0.246 mmol, 1 eq) was reacted with
phenylacetylene (25 mg, 0.246 mmol, 1 eq) to give 10 as a pale
white solid (104 mg, 0.114 mmol, 46%). Crystals suitable for the X-
ray crystal structure analysis were obtained by slow evaporation of
a saturated solution of 10 in dichloromethane at ꢀ34 ꢁC. Anal.
Calcd. for C40H12BF20P: C, 52.55; H, 1.32. Found: C, 52.34; H, 1.47.
Appendix A. Supplementary data
Supplementary data related to this article can be found at
http://dx.doi.org/10.1016/j.jorganchem.2013.06.005.
Mp: 247 ꢁC (DSC). 1H NMR (600 MHz, CD2Cl2, 299 K):
d
¼ 8.35 (d,
3JPH ¼ 57.2 Hz, 1H, ]CHB), 8.32 (d, JPH ¼ 63.5 Hz, 1H, ]CH), 7.33
(m, 1H, p-PhB), 7.27 (m, 2H, m-PhB), 7.26 (m, 1H, p-PhA), 7.19 (m, 2H,
m-PhA), 7.04 (m, 2H, o-PhB), 6.98 (m, 2H, o-PhA). 13C{1H} NMR
3
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(151 MHz, CD2Cl2, 299 K):
d
¼ 183.8 (br, ]CHB), 158.8 (]CH), 138.8
(d, 3JPC ¼ 14.2 Hz, i-PhA), 135.4 (br, PCB)a, 134.7 (d, 3JPC ¼ 17.0 Hz, i-
PhB), 129.44 (p-PhA)t, 129.40 (d, J ¼ 1.7 Hz, p-PhB)t, 129.2 (m-PhB),
129.0 (m-PhA), n.o. (]CP), 128.2 (d, JPC ¼ 4.5 Hz, o-PhB), 126.7 (o-
3
PhA), 122.3 (m br, i-C6F5B), 100.6 (dm, 1JPC ¼ 71.4 Hz, i-C6FP5) [C6F5 not
listed; from GHMBC experiment, t tentative assignment]. 11B{1H}
a
NMR (192 MHz, CD2Cl2, 299 K):
(564 MHz, CD2Cl2, 299 K):
d
¼ ꢀ9.7 (d, JPB w 38 Hz). 19F NMR
d
¼ ꢀ126.4 (2F, o), ꢀ141.1 (1F, p), ꢀ157.8
19
(b) G.C. Welch, D.W. Stephan, J. Am. Chem. Soc. 129 (2007) 1880e1881;
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F
pm
¼ 16.7], ꢀ132.3 (m, 2F, o), ꢀ160.7 (t,
19
3JFF ¼ 20.9 Hz, 1F, p), ꢀ165.2 (m, 2F, m) (BC6F5) [Dd
F
pm
¼ 4.5]. 31
P
{1H} NMR (243 MHz, CD2Cl2, 299 K):
d
¼ 1.4 (m, partially relaxed
JPB w 40 Hz).

C. Rosorius et al. / Journal of Organometallic Chemistry 744 (2013) 149e155
155
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Angew. Chem. Int. Ed. 49 (2010) 9475e9478;
(g) FLP þ conjugated ynones: B.-H. Xu, G. Kehr, R. Fröhlich, B. Wibbeling,
B. Schirmer, S. Grimme, G. Erker, Angew. Chem. 51 (2012) 7321e7324 [124
(2012) 10359];
(k) S. Schwendemann, T.A. Tumay, K.V. Axenov, I. Peuser, G. Kehr, R. Fröhlich,
G. Erker, Organometallics 29 (2010) 1067e1069;
Angew. Chem. Int. Ed. 50 (2011) 7183e7186 [51 (2012) 10213].
[8] See e.g. B(C6F5)3: 11B NMR:
d 60.0. T. Beringhelli, D. Donghi, D. Maggioni,
(l) D.W. Stephan, S. Greenberg, T.W. Graham, P. Chase, J.J. Hastie, S.J. Geier,
J.M. Farrell, C.C. Brown, Z.M. Heiden, G.C. Welch, M. Ullrich, Inorg. Chem. 50
(2011) 12338e12348;
(m) J.M. Farrell, Z.M. Heiden, D.W. Stephan, Organometallics 30 (2011) 4497e
4500;
G. D’Alfonso Coord. Chem. Rev. 252 (2008) 2292e2313
[9] (a) For the synthesis of 4 see the Supporting Information. Modified pro-
cedure according to the synthesis of (C6F5)2PeCCe described in Ref. [3];
(b) (C6F5)2PeCl: D.D. Magnelli, G. Tesi, J.U. Lowe, W.E. McQuiston Inorg.
Chem. 5 (1966) 457e461;
(n) Z.M. Heiden, D.W. Stephan, Chem. Commun. 47 (2011) 5729e5731;
(o) J.S. Reddy, B.-H. Xu, T. Mahdi, R. Fröhlich, G. Kehr, D.W. Stephan, G. Erker,
Organometallics 31 (2012) 5638e5649.
G. Mancino, A.J. Ferguson, A. Beeby, N.J. Long, T.S. Jones, J. Am. Chem. Soc.
127 (2005) 524e525.
[10] (a) D.J. Parks, R.E. von H. Spence, W.E. Piers, Angew. Chem. 107 (1995)
895e897;
[7] (a) FLP þ CO2: C.M. Mömming, E. Otten, G. Kehr, R. Fröhlich, S. Grimme,
D.W. Stephan, G. Erker Angew. Chem. 121 (2009) 6670e6673;
Angew. Chem. Int. Ed. 48 (2009) 6643e6646;
Angew. Chem. Int. Ed. 34 (1995) 809e811;
(b) D.J. Parks, W.E. Piers, G.P.A. Yap, Organometallics 17 (1998) 5492e
5503.
I. Peuser, R.C. Neu, X. Zhao, M. Ulrich, B. Schirmer, J.A. Tannert, G. Kehr,
R. Fröhlich, S. Grimme, G. Erker, D.W. Stephan, Chem. Eur. J. 17 (2011) 9640e
9650;
C. Appelt, H. Westenberg, F. Bertini, A.W. Ehlers, J.C. Slootweg, K. Lammertsma,
W. Uhl, Angew. Chem. 123 (2011) 4011e4014;
[11] For other examples of related alkenyl-B(C6F5)2 structures see: (a) C. Chen,
F. Eweiner, B. Wibbeling, R. Fröhlich, S. Senda, Y. Ohki, K. Tatsumi,
S. Grimme, G. Kehr, G. Erker, Chem. Asian J. 5 (2010) 2199e2208;
(b) C. Chen, G. Kehr, R. Fröhlich, G. Erker, J. Am. Chem. Soc. 132 (2010)
13594e13595;
Angew. Chem. Int. Ed. 50 (2011) 3925e3928;
X. Zhao, D.W. Stephan, Chem. Commun. 47 (2011) 1833e1835;
S. Roters, C. Appelt, H. Westenberg, A. Hepp, J.C. Slootweg, K. Lammertsma,
W. Uhl, Dalton Trans. 41 (2012) 9033e9045;
(c) C. Chen, T. Voss, R. Fröhlich, G. Kehr, G. Erker, Org. Lett. 13 (2011) 62e65;
(d) O. Ekkert, G. Kehr, R. Fröhlich, G. Erker, Chem. Commun. 47 (2011)
10482e10484;
E. Theuergarten, J. Schlösser, D. Schlüns, M. Freytag, C.G. Daniliuc, P.G. Jones,
M. Tamm, Dalton Trans. 41 (2012) 9101e9110;
(e) C. Eller, G. Kehr, C.G. Daniliuc, R. Fröhlich, G. Erker, Organometallics 32
(2013) 384e386.
M. Harhausen, R. Fröhlich, G. Kehr, G. Erker, Organometallics 31 (2012)
2801e2809;
F. Bertini, V. Lyaskovskyy, B.J.J. Timmer, F.J.J. de Kanter, M. Lutz, A.W. Ehlers,
J.C. Slootweg, K. Lammertsma, J. Am. Chem. Soc. 134 (2012) 201e204;
L.J. Hounjet, C.B. Caputo, D.W. Stephan, Angew. Chem. 124 (2012) 4792e
4795;
[12] T. Wiegand, H. Eckert, O. Ekkert, R. Fröhlich, G. Kehr, G. Erker, S. Grimme,
J. Am. Chem. Soc. 134 (2012) 4236e4249, and references therein.
[13] (a) P. Spies, G. Kehr, K. Bergander, B. Wibbeling, R. Fröhlich, G. Erker, Dalton
Trans. (2009) 1534e1541;
(b) C.M. Mömming, G. Kehr, B. Wibbeling, R. Fröhlich, G. Erker, Dalton Trans.
39 (2010) 7556e7564.
Angew. Chem. Int. Ed. 51 (2012) 4714e4717;
[14] S. Moebs-Sanchez, G. Bouhadir, N. Saffon, L. Maron, D. Bourissou, Chem.
Commun. (2008) 3435e3437.
[15] (a) M.A. Dureen, D.W. Stephan, J. Am. Chem. Soc. 131 (2009) 8396e8397;
(b) C. Chen, R. Fröhlich, G. Kehr, G. Erker, Chem. Commun. 46 (2010)
3580e3582;
C. Jiang, D.W. Stephan, Dalton Trans. 42 (2013) 630e637;
(b) Reduction of CO2 with FLPs: A.E. Ashley, A.L. Thompson, D. O’Hare Angew.
Chem. Int. Ed. 48 (2009) 9839e9843;
Angew. Chem. 121 (2009) 10023e10027;
A. Berkefeld, W.E. Piers, M. Parvez, J. Am. Chem. Soc. 132 (2010) 10660e
10661;
(c) M.A. Dureen, C.C. Brown, D.W. Stephan, Organometallics 29 (2010)
6594e6607;
G. Ménard, D.W. Stephan, J. Am. Chem. Soc. 132 (2010) 1796e1797;
G. Ménard, D.W. Stephan, Angew. Chem. Int. Ed. 50 (2011) 8396e8499;
Angew. Chem. 123 (2011) 8546e8549;
S.D. Tran, T.A. Tromnic, W. Kaminsky, D.M. Heinekey, J.M. Mayer, Inorg. Chim.
Acta 369 (2011) 126e132;
(d) M.A. Dureen, C.C. Brown, D.W. Stephan, Organometallics 29 (2010)
6422e6432;
(e) C. Jiang, O. Blacque, H. Berke, Organometallics 29 (2010) 125e133;
(f) P. Feldhaus, B. Schirmer, B. Wibbeling, C.G. Daniliuc, R. Fröhlich,
S. Grimme, G. Kehr, G. Erker, Dalton Trans. 41 (2012) 9135e9142.
M.J. Sgro, J. Dömer, D.W. Stephan, Chem. Commun. 48 (2012) 7253e7255;
(c) FLP þ alkenes: J.S.J. McCahill, G.C. Welch, D.W. Stephan Angew. Chem.
119 (2007) 5056e5059;
[16] See for a comparison: O. Ekkert, G.G. Miera, T. Wiegand, H. Eckert,
B. Schirmer, J.L. Petersen, C.G. Daniliuc, R. Fröhlich, S. Grimme, G. Kehr,
G. Erker Chem. Sci. 4 (2013) 2657e2664.
Angew. Chem. Int. Ed. 46 (2007) 4968e4971;
C.M. Mömming, S. Frömel, G. Kehr, R. Fröhlich, S. Grimme, G. Erker, J. Am.
Chem. Soc. 131 (2009) 12280e12289;
[17] For recently reported related vicinal P/Al FLPs see: T. Holtrichter-Rößmann,
C. Rösener, J. Hellmann, W. Uhl, E.-U. Würthwein, R. Fröhlich, B. Wibbeling
Organometallics 31 (2012) 3272e3283.
M. Ullrich, K.S.-H. Seto, A.J. Lough, D.W. Stephan, Chem. Commun. (2009)
2335e2337;
[18] S. Schwendemann, R. Fröhlich, G. Kehr, G. Erker, Chem. Sci. 2 (2011)
1842e1849.
C.M. Mömming, G. Kehr, B. Wibbeling, R. Fröhlich, B. Schirmer, S. Grimme,
G. Erker, Angew. Chem. 122 (2010) 2464e2467;
Angew. Chem. Int. Ed. 49 (2010) 2414e2417;
[19] Z. Otwinowski, W. Minor, Methods Enzymol. 276 (1997) 307e326.
[20] Z. Otwinowski, D. Borek, W. Majewski, W. Minor, Acta Crystallogr. A59
(2003) 228e234.
T. Voss, J.-B. Sortais, R. Fröhlich, G. Kehr, G. Erker, Organometallics 30 (2011)
584e594. FLP þ SO2;
[21] G.M. Sheldrick, Acta Crystallogr. A46 (1990) 467e473.
[22] G.M. Sheldrick, Acta Crystallogr. A64 (2008) 112e122.
[23] (a) A.G. Massey, A.J. Park, F.G.A. Stone, Proc. Chem. Soc. (1963) 212;
(b) A.G. Massey, A.J. Park, J. Organomet. Chem. 2 (1964) 245e250;
(c) A.G. Massey, A.J. Park, J. Organomet. Chem. 5 (1966) 218e225.
M. Sajid, A. Klose, B. Birkmann, L. Liang, B. Schirmer, T. Wiegand, H. Eckert,
A.J. Lough, R. Fröhlich, C.G. Daniliuc, S. Grimme, D.W. Stephan, G. Kehr,
G. Erker, Chem. Sci. 4 (2013) 213e219;