Reactions of a cationic geminal Zr+/P pair with small molecules

Article abstract of DOI:10.1021/ja3110076

The metallocene cation complex [Cp*₂ZrCH₃] ⁺[B(C₆F₅)₄]^- inserts the phosphino-substituted alkyne Ph-Ci - 1/4C-PPh₂ into the [Zr]-CH₃ bond to form the internally phosphane-stabilized cation [Cp*₂Zr-C(=CMePh)PPh₂]⁺ (10). Complex 10 adds alkyl isocyanides as well as pivalonitrile at a lateral site at the bent metallocene wedge with retention of the Zr-P bond. Complex 10 acts as a reactive frustrated Lewis pair toward heterocumulenes, undergoing Zr⁺/P addition reactions to the carbonyl groups of an alkyl isocyanate and of carbon dioxide to form the respective five-membered metallaheterocyclic adducts 13 and 14. With mesityl azide complex 10 undergoes a Zr⁺/P FLP N,N-addition reaction at the terminal azide nitrogen atom to form the four-membered FLP cycloadduct 15. The Zr⁺/P FLP is a reactive hydrogen activator. In a stoichiometric reaction it generates a hydridozirconocene cation that subsequently serves as a hydrogenation catalyst for various olefinic or acetylenic substrates. The Zr⁺/P pair 10 undergoes selective 1,4-addition reactions to conjugated enones and to a conjugated ynone to give the corresponding seven-membered metallacyclic Zr⁺/P FLP addition products. Many compounds of this study were characterized by X-ray diffraction.

Full text of DOI:10.1021/ja3110076

Article
pubs.acs.org/JACS
+
Reactions of a Cationic Geminal Zr /P Pair with Small Molecules
§
Xin Xu, Gerald Kehr, Constantin G. Daniliuc, and Gerhard Erker*
̈
̈ ̈
Organisch-Chemisches Institut, Universitat Munster, Corrensstrasse 40, D-48149 Munster, Germany
*
S Supporting Information
ABSTRACT: The metallocene cation complex
+
−
[
Cp* ZrCH ] [B(C F ) ] inserts the phosphino-substituted
2 3 6 5 4
alkyne Ph−CC−PPh into the [Zr]-CH bond to form the
2
3
internally phosphane-stabilized cation [Cp* Zr−C(
2
+
CMePh)PPh ] (10). Complex 10 adds alkyl isocyanides as
2
well as pivalonitrile at a lateral site at the bent metallocene
wedge with retention of the Zr−P bond. Complex 10 acts as a
reactive frustrated Lewis pair toward heterocumulenes, under-
+
going Zr /P addition reactions to the carbonyl groups of an
alkyl isocyanate and of carbon dioxide to form the respective
five-membered metallaheterocyclic adducts 13 and 14. With
+
mesityl azide complex 10 undergoes a Zr /P FLP N,N-addition reaction at the terminal azide nitrogen atom to form the four-
+
membered FLP cycloadduct 15. The Zr /P FLP is a reactive hydrogen activator. In a stoichiometric reaction it generates a
hydridozirconocene cation that subsequently serves as a hydrogenation catalyst for various olefinic or acetylenic substrates. The
+
Zr /P pair 10 undergoes selective 1,4-addition reactions to conjugated enones and to a conjugated ynone to give the
+
corresponding seven-membered metallacyclic Zr /P FLP addition products. Many compounds of this study were characterized
by X-ray diffraction.
INTRODUCTION
Scheme 1
■
Frustrated Lewis Pair (FLP) chemistry has developed at an
1
impressive pace in recent years. The phosphane/borane
2
3
systems (and to a lesser extent amine/borane or carbon
4
based Lewis base/borane combinations) have had a substantial
impact on the metal-free activation and/or binding of small
molecules. While the Lewis base in FLPs has varied
considerably, most FLPs have involved boron Lewis acids;
5
especially RB(C F ) derivatives have been used in the
6
5 2
advancement of FLP chemistry. There have been attempts to
use Lewis acid components other than the strongly electro-
philic C F containing boranes. Some progress has been made
6
5
6
in using aluminum based Lewis acids. There have been cases
of carbon based systems, and quite recently some strongly
4
Scheme 2
electrophilic halophosphonium cation systems have successfully
7
been tested.
It is probably natural to return to systems that contain
8
transition metals. D. Stephan et al. have exchanged the borane
+
component for [Cp ZrCH ] in a P/B FLP adduct of N O.
2
3
2
+
They have also used the intermolecular Zr /P pair 3 for
trapping N O (see Scheme 1). In a beautiful series of papers,
9
2
D. F. Wass et al. have described various intramolecular FLPs
based on the group 4 bent metallocene cations (and a pending
phosphane base). Some of these systems were shown to bind,
1
2
electrophilic zirconium center. This posed the question
+
whether 10 might be able to serve as a new Zr /P FLP despite
its apparently strong coordinative P−Zr interaction. The first
results of our investigation about the FLP features of the Zr /P
10
e.g., CO , or to activate dihydrogen. Scheme 1 shows typical
2
+
examples of this FLP type (5 to 7).
We had recently prepared the Zr /P system 10 by an
+
system 10 will be described and discussed in this account.
insertion reaction of the diphenylphosphino-substituted alkyne
+
9
into the [Zr]-CH bond of [Cp* Zr-CH ] cation 8 (see
Received: November 8, 2012
Published: March 25, 2013
3
2
3
1
1
Scheme 2). The product 10 contains an unsaturated
©
2013 American Chemical Society
6465
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+
RESULTS AND DISCUSSION
Table 1. Selected Structural Data of the Zr /P Cation 10 and
Its Isonitrile Adducts 11a and 11b
■
“
a
Reactions with Typical Donor Ligands Leading to
Normal” Coordination Behavior. We first reacted the
b
t
n
comp (lig)
10 (−)
11a ( BuNC)
11b ( BuNC)
zirconium complex 10 with two active alkyl isonitriles. Both t-
butyl and n-butyl isocyanide coordinated to the electrophilic
zirconium center of the cationic complex 10. Both products 11a
and 11b were isolated from the reaction mixtures in good yields
Zr1−C1
Zr1−C4
Zr1−P1
C1−P1
2.290(3)
2.358(4)
2.317(4)
2.704(1)
1.775(4)
1.349(6)
40.3(1)
2.350(3)
2.331(3)
2.683(1)
1.771(3)
1.353(4)
40.5(1)
-
2.667(1)
1.804(3)
1.344(4)
41.8(1)
-
(
>70%). Both compounds were characterized by X-ray
C1−C2
diffraction (see Figures 1 and 2). Isonitrile coordination to
C1−Zr1−P1
C1−Zr1−C4
Zr1−P1−C1
Zr1−C4−N1
C4−N1−C5
zirconium in both cases occurred at the available lateral site in
118.3(1)
59.3(1)
120.2(1)
59.6(1)
13
the bent metallocene σ-ligand plane proximal to the Zr−P
57.9(1)
-
vector.
178.5(4)
178.3(4)
178.6(3)
176.2(4)
-
a
b
Bond lengths in Å, angles in deg. Ref 11.
Table 2. Selected NMR Data of the Complexes 10, 11a, and
a
11b
b
t
n
comp (lig)
δ 31
10 (−)
17.6
11a ( BuNC)
11b ( BuNC)
P
−76.5
−76.1
δ 13C1 ( JPC)
δ 13C2 ( JPC)
δ 13CN
1
186.2(103.7)
170.6(17.3)
-
156.3(119.8)
169.4(17.2)
n.o.
156.3(119.6)
169.2(17.5)
159.9(br)
2
a
Chemical shifts: rel. TMS [δ 13C(TMS) = 0, δ 13C(CD Cl ) = 53.8],
2 2
b
3
1
rel. external H PO (80%, δ P = 0), coupling constants in Hz. Ref
3
4
1
1.
Scheme 3
t
Figure 1. Molecular structure of the BuNC adduct 11a (only the
cation is shown).
We have also added pivalonitrile to the zirconium center of
complex 10 and obtained the Me C−CN adduct 11c (69%
3
−1
isolated). It features the IR (CN) band at 2261 cm . The
13
31
C NMR nitrile resonance was observed at δ 141.4 and the P
NMR signal was located at δ −64.8.
Compound 11c was also characterized by X-ray diffraction. It
shows the typical bonding parameters of the Zr−C[P]
CMePh unit [Zr1−C1 2.353(4) Å, C1−C2 1.349(6) Å, C1−P1
1
.786(4) Å]. Addition of the nitrile donor ligand to the
electrophilic zirconium center [Zr1−N1 2.296(4) Å, N1−C4
1
.132 (5) Å, angle Zr1−N1−C4 177.7 (3)°] in 11c has also left
the adjacent Zr1−P1 bond almost unaffected [Zr1−P1:
2
.711(1) Å] (see Figure 3).
Figure 2. View of the molecular structure of adduct 11b (only the
cation is shown).
We conclude that the cation 10 first appears to add a variety
of common donor ligands to the vacant lateral coordination site
adjacent to the inherent phosphane donor by making use of its
available empty valence orbital. This additional coordination to
Upon coordination of the isocyanide ligands to the Zr center
of 10 to form 11a and 11b, respectively (see Table 1), the
principal coordination geometry of the ene-phosphino ligand is
retained. Isonitrile coordination has resulted in a shifting of the
respective 31P NMR resonance of 11a and 11b to negative
values as compared to 10 (see Table 2). We conclude that the
0
the d -metal center has apparently no pronounced influence on
the remaining ligands in the metallocene σ-ligand plane. The
coordinatively saturated complexes 11 show very similar
structural parameters as compared to their common unsatu-
+
rated precursor 10. The Zr /P linkage is not much affected.
+
addition of the isonitriles to Zr /P complex 10 occurs readily.
FLP-Reminiscent Reaction Behavior of Complex 10
In the coordination compounds the metal−phosphane bond is
retained.
toward Unsaturated Small Organic Molecules. The
situation changed markedly when we reacted the Zr /P
+
6
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Scheme 4
Figure 3. Molecular structure of complex 11c (only the cation is
depicted).
complex 10 with a variety of other unsaturated reagents. We
first treated 10 with N O. This resulted in oxidation of the
2
phosphane and consequently to cleavage of the Zr−P linkage
with formation of a new zirconium−oxygen bond. The X-ray
crystal structure analysis of the product 12 (see Figure 4)
Figure 5. Molecular structure of the isocyanate addition product 13
only the cation is depicted).
(
C1 2.393(5) Å, C1−P1 1.801(4) Å, O1−C4 1.325(6) Å). To
this core the exocyclic C double bond is attached via C1
t
(
C1−C2 1.351(7) Å) and the N Bu unit at C4 (C4−N1
Figure 4. View of the molecular structure of compound 12 (only the
cation is shown).
1
.257(6) Å, angle C4−N1−C5 127.4(5)°). The phosphorus
atom inside the five-membered ring is a tetra-substituted
phosphonium center. The zirconocene unit shows the typical
bonding features of a group 4 bent metallocene unit (σ-ligand
angle C1−Zr1−O1 79.55(14)°).
showed the newly formed central four-membered metal-
laheterocyclic core structure of 12 with bond lengths of 2.399
(
6) Å (Zr1−C1), 1.772(7) Å (C1−P1), 1.543(5) Å (P1−O1),
In solution, complex 13 exhibits a typical borate 11B NMR
31
and 2.168(5) Å (O1−Zr1) (C1−C2:1.325(9) Å). In solution,
compound 12 shows a P NMR signal at δ 17.4.
signal at δ −16.7. The cation shows a P NMR signal with a
3
1
phosphonium like chemical shift at δ 33.7. The heterocyclic
13
Complex 10 was then reacted with the heterocumulenes t-
core of the molecule features C NMR signals at δ 151.3
1
1
butyl isocyanate and with CO , respectively. In both cases
(−O−CN; J = 158.5 Hz) and δ 158.5 (C[Zr], J
=
2
PC
PC
insertion into the Zr−P linkage was observed, forming the
18.5 Hz). The signal of the exocyclic carbon of this CC
2
products 13 and 14 which at least formally resemble typical
double bond shows up at δ 174.5 ( J = 6.4 Hz) and we have
PC
+
1
Zr /P FLP addition products to the π-systems of these
found a single sharp H NMR resonance of the ten methyl
reagents. The reaction of 10 with tert-butyl isocyanate was
carried out in dichloromethane/pentane for 3 d at room
temperature. Workup gave the product 13 as a yellow solid in
close to 80% yield. It was characterized by C, H, N elemental
analysis, by spectroscopy, and by X-ray diffraction.
groups of the Cp* Zr bent metallocene unit.
2
Complex 10 also showed a frustrated Lewis pair-like behavior
15
toward carbon dioxide. It reacted rapidly with CO under
2
+
mild conditions (0 °C to r.t.) to give the Zr /P addition
product 14 to the carbonyl functionality of carbon dioxide. The
product 14 was isolated as a yellow solid in 77% yield. Single
crystals suited for the X-ray crystal structure analysis were
obtained from dichloromethane/cyclopentane at low temper-
ature (−35 °C). The structure shows that the electrophilic
zirconium Lewis acid center of 10 has added to a former
The X-ray crystal structure analysis revealed that the carbonyl
group of the isocyanate reagent had added across the Zr−P
14
bond of the starting material 10. The product 13 contains a
new Zr−O bond (2.075(3) Å) and the phosphane has added to
the sp-carbon atom of the isocyanate (P1−C4 1.848(5) Å).
The molecule contains a central metallaheterocyclic core (Zr1−
carbonyl oxygen atom of the CO molecule; the Zr−P linkage
2
6
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of 10 was opened during the reaction and the attached
phosphane Lewis base had attacked the CO carbonyl carbon
2
atom. In the resulting five-membered heterocyclic core of 14
we have found typical bond length of 2.097(2) Å (Zr1−O1),
2.402(3) Å (Zr1−C1), and 1.789(3) Å (P1−C1). The newly
formed P1−C4 bond length is markedly longer at 1.887(3) Å
and the internal C4−O1 bond length is 1.290(4) Å. The
remaining carbonyl group at C4 is shorter (C4−O2: 1.197(4)
Å), as expected. The remaining bonding features of the cationic
metallocene/phosphonium system 14 are unexceptional (see
Figure 6).
Figure 7. Molecular structure of the mesitylazide adduct 15 (only the
cation is shown).
(
1.789(3) Å) and P1−N1 (1.654(2) Å) linkages (angles
Zr1−N1−P1 105.2(1)°, Zr1−C1−P1 96.3(1)°, C1−P1−N1
3.0(1)°). There is an exocyclic CC bond terminated at C1
9
(
C1−C2 1.347(4) Å). The N -mesityl unit is trans-configurated
3
at the N2−N3 double bond (1.262(3) Å) and it shows bond
alternation (N1−N2 1.386 (3) Å).
In solution, complex 15 shows the typical H/ C NMR
features of the Cp* Zr subunit and the endocyclic PPh
1
13
2
2
Figure 6. View of the molecular structure of the CO addition product
2
31
13
building block ( P: δ 12.3). The C NMR signals of the
1
4 (only the cation is depicted).
1
exocyclic CC double bond occur at δ 158.8 ( J = 8.0 Hz)
PC
2
and δ 172.2 ( J = 2.3 Hz), respectively.
The CO addition product 14 features a strong IR (CO)
PC
2
−1
13
Reactions with Dihydrogen. Since the cationic complex
10 showed some frustrated Lewis pair-like behavior toward the
heterocumulenes and the azide reagent, it was tempting to learn
band at 1699 cm . The carbonyl carbon C NMR resonance
1
was found at δ 165.5 with a coupling constant of J = 125.1
PC
3
1
Hz. Compound 14 shows a phosphonium P NMR signal at δ
+
1
3
whether the Zr /P pair could heterolytically split dihydrogen
2
7.6. The C NMR signals of the exocyclic CC double bond
=
PC PC
18
1
2
similar to many main group element FLPs, although some of
the resulting reactions would be anticipated to show
complications due to the known, sometimes high reactivity of
occur at δ 155.7 ( J = 27.0 Hz, C[Zr]) and δ 175.8 ( J
7
.2 Hz), respectively.
19
an ensuing cationic zirconium hydride product.
Scheme 5
We first reacted the cationic zirconocene/phosphane
complex 10 with dihydrogen in dichloromethane solution. A
solution of 10 in CH Cl2 was exposed to a hydrogen
2
atmosphere (1.5 bar) for 2 h at room temperature. Covering
with pentane eventually gave a crystalline solid formed from the
two-phase system that was recovered in ca. 50% yield. The
obtained single crystals were composed of a 1:1 mixture of
Cp* ZrCl (19) and the phosphonium salt 20. In the crystal
2
2
+
(
see Figure 8) one observes the separate bent metallocene
Compound 10 reacts in a typical Zr /P FLP fashion with
−
molecule 19 and the cation and [B(C F ) ] anion of the salt
mesityl azide. Mes-N reacts rapidly even at low temperature
−35 °C) with the zirconium cation complex 10. We isolated
6 5 4
3
2
0. The cation of 20 features a tetracoordinated phosphonium
(
phosphorus center that has two phenyl groups and the Z−
the product as a red crystalline solid in 70% yield. Complex 15
was characterized by C, H, N elemental analysis, by
spectroscopy, and by X-ray diffraction (single crystals were
obtained from dichloromethane/cyclopentane at −35 °C). The
structure of 15 revealed that the Zr−P bond of the starting
CHCPh(CH ) substituent bonded to it. The fourth ligand at
3
P1 is a −CH Cl group.
2
We dissolved the solid in CD Cl and monitored the typical
2
2
1
13
H/ C NMR spectra of the Cp* ZrCl bent metallocene
2
2
+
11
19
−
material 10 had opened and the cationic Zr Lewis acid and the
adjacent phosphane Lewis base had both added to the terminal
dichloride, the typical B/ F NMR signals of the [B(C F ) ]
6 5 4
anion and the characteristic signals of the newly formed
14b,16,17
1
mesityl azide nitrogen atom.
That resulted in the
phosphonium cation 20 (see Scheme 6). Its H NMR spectrum
formation of a four-membered metallaheterocyclic structure.
The “kite-shaped” Zr, C, P, N core of complex 15 features two
long Zr1−C1 (2.368(3) Å) and Zr1−N1 (2.247(2) Å) bonds
shows a doublet of quartets of the newly attached proton at the
2
4
olefinic carbon atom at δ 6.30 ( JPH = 21.8 Hz, JHH = 1.4 Hz);
13
1
C: δ 102.0 ( JPC = 90.8 Hz) and a doublet of the −CH
group attached at phosphorus [δ 4.03, J = 5.8 Hz, C: δ
Cl
2
2
13
(
angle C1−Zr1−N1 65.6(1)°) and two short P1−C1
PH
6
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conditions. Workup with pentane after the short reaction time
gave yellow crystals of a zirconium containing salt 21 that was
characterized by X-ray diffraction. The crystal contains a
metallocene cation to which 1 equiv of THF is coordinated
(
Zr1−O1 2.240(3) Å). The remaining adjacent σ-ligand site at
the cationic bent metallocene unit is to ca. 25% occupied by
chloride (which we assume to originate from some small
23
residual amount of CH Cl2 from the preparation). The
2
remaining 75% of that site seem to be occupied by hydride (see
−
Figure 9). We also found the independent [B(C F ) ]
6
5 4
counteranion in the crystal.
Figure 8. Molecular geometry of the 19/20 mixture in the crystal
(
only the cation is shown).
Scheme 6
Figure 9. View of the molecular structure of the (hydrido)-
zirconocene(THF) cationic product 21 (the σ-ligand site is ca. 25%
occupied by chloride).
1
In the H NMR spectrum of compound 21 in C D Br we
6
5
observed the signals of the THF ligand at δ 3.14 and 1.54 and
the large sharp signal of the ten methyl groups at the Cp*-rings
(
δ 1.66) plus a singlet at δ 7.73 (1H rel. intensity) that we
+
24
associate with the formal [Zr] -H hydride.
The stoichiometric alkenylphosphane coproduct 22 was
recovered from the organic solution (admixed with a small
1
3
1
5.3 (1JPC = 61.4 Hz)]. The 31P NMR signal of 20 occurs at δ
metallocene amount). Compound 22 shows a typical H NMR
4
4
4.1.
dd at δ 2.05 ( J = 1.4 Hz, J = 0.7 Hz) of the methyl
HH PH
+
2
4
Apparently the Zr /P cation 10 is quite reactive toward
substituent and a dq ( J = 3.9 Hz, J = 1.4 Hz) of the
PH HH
3
1
dihydrogen. We assume that 10 rapidly splits dihydrogen
heterolytically to generate the hydridozirconium/phosphonium
system 16. Having a Brønsted acidic phosphonium salt
geminally attached to a zirconium−carbon σ-ligand is
apparently not a stable situation. We assume fast protonolytic
cleavage of the Zr−C(sp ) σ-bond occurring to possibly
generate 17. In dichloromethane solution, the highly reactive
metallocene cation may abstract a chloride anion from the
solvent with the aid of the phosphane nucleophile. This should
produce the phosphonium salt 20 which we have observed and
olefinic proton at δ 6.32. The P NMR resonance of
compound 22 is at δ −25.0.
The origin of the newly introduced hydrogen atoms from
dihydrogen were confirmed by carrying out the reaction under
20
2
analogous conditions with D . The H NMR spectrum showed
2
2
the [Zr]-D resonance at ca. 7.70 (in bromobenzene) and the
olefinic D-[C](PPh ) resonance at δ 6.34.
2
We investigated whether the 10/H system might be also
2
suited for hydrogen transfer. In a first experiment we exposed a
+
styrene solution in C D Br containing 1 mol % of the Zr /P
6
5
Cp* Zr(H)Cl. It is known that hydridozirconocenes may react
complex 10 (and 10 mol % of ferrocene as an internal
standard) briefly to an atmosphere of dihydrogen at 1.5 bar.
The reaction was stopped after 10 min and the composition of
2
21
with dichloromethane. Consequently, 17 in situ generated in
this sequence could have been converted to the observed
1
Cp* ZrCl2 product 19 (either directly or via 18) (plus
the solution monitored by H NMR spectroscopy to reveal a
2
methylchloride that was probably lost under our reaction
57% conversion of the olefin to ethylbenzene under these mild
conditions (Table 3, entry 1). After optimizing the reaction
conditions, we found that the hydrogenation reaction can be
completed with 1 mol % of 10 in 30 min (Table 3, entry 2).
Even with a very small amount of 10 (0.5 mol %) the reaction
still gave 63% conversion in 1 h and 86% conversion in 3.5 h
(Table 3, entries 3 and 4), respectively. A few other olefins and
2
2
conditions).
This tentative description of the reaction course taken upon
treatment of 10 with H was supported by an experiment where
2
1
0 was treated with dihydrogen in d -benzene solution in the
6
presence of a small quantity of THF. Again, complex 10 reacted
rapidly with H (1.5 bar, 10 min) under these mild reaction
2
6
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Table 3. Hydrogenation of Alkenes and an Alkyne Catalyzed
by Complex 10
C6 1.342(4) Å, C6−C5 1.335(4) Å, C5−C4 1.507(4) Å). The
enolate is part of the seven-membered ring, it is consequently
Z-configurated (dihedral angle O1−C6−C5−C4 −4.2(5)°). It
has the pair of phenyl substituents attached at carbon atoms C6
and C4, which has formed the new bond to phosphorus (P1−
C4 1.882(3) Å), thereby closing the metallacycle (P1−C1
a
1
.818(3) Å, C1−C2 1.353(4) Å, C1−Zr1 2.487(3) Å) (see
Figure.10).
b
entry
substrate
[cat.]/[sub.] (%)
time (min)
conversion (%)
1
2
3
4
5
6
7
8
A
A
A
A
B
C
D
D
1.0
1.0
0.5
0.5
1.0
1.0
1.0
1.0
10
30
57
c
93
d
60
63
210
120
60
86
e
99(77)
94
f
30
73(13:1)
f
90
97(7:1)
a
Room temperature, 1.5 bar H , C D Br as the solvent, substrate (0.5
2
6
5
b
mmol). NMR yield determined relative to ferrocene internal
standard. Ca. 0.3% 2,4-diphenyl-1-butene. Ca. 0.5% 2,4-diphenyl-1-
butene. Yield of isolated product. Mol ratio of cis-stilbene/1,2-
c
d
e
f
diphenylethane.
an alkyne were hydrogenated with the 10/H system as well.
2
Vinylferrocene was quantitatively converted to ethylferrocene
under our typical hydrogenation conditions (1 mol % 10,
C D Br solution, 1.5 bar H , r.t.). The product was isolated in
6
5
2
7
7% yield. Treatment with D2 gave (1,2-dideuteroethyl)-
+
Figure 10. Molecular structure of the Zr /P 1,4-addition product 25a
ferrocene instead. t-Butylethene gave 2,2-dimethylbutane and
tolane gave a mixture of cis-stilbene (major) and 1,2-
diphenylethane (minor product, see Table 3 and the
Supporting Information for details).
(only the cation is depicted).
+
The Zr /P system 10 also undergoes an analogous 1,4-
addition reaction to the conjugated enone 24b (R = Ph) to
yield the seven-membered metallacycle 25b (isolated in 77%
yield). Complex 25b has also been characterized by X-ray
diffraction; its structural features are similar to those of complex
It is conceivable that some conventional Ziegler−Natta
catalyst generated from 10 under these conditions is
responsible for the styrene hydrogenation activity. Therefore,
we carried out a number of control and reference experiments
+
26
+
−
25
2
5a. A view of the structure is provided with the Supporting
using either [Cp* ZrMe] [B(C F ) ]
or [Cp* ZrH]
2
2
6
5 4
3
1
Information. In solution, compound 25b features a P NMR
(the latter in situ generated under various conditions) with or
13
without added phosphanes for the styrene hydrogenation
reaction. In several of these examples we found minute
amounts of additional products derived from styrene
dimerization pathways, namely, 1,3-diphenylbutane or 2,4-
diphenyl-1-butene (for details see the Supporting Information).
However, we regard these observed differences as probably too
small to draw any solid mechanistic conclusion from them at
this time.
signal at δ 26.6 [25a: δ 22.1; C NMR of the [Zr]−O−
3
2
C(Ph)CH unit: δ 160.6 ( JPC = 7.5 Hz), δ 100.7 ( JPC = 9.7
1
3
Hz), corresponding CH− H NMR signal at δ 4.56 ( JPH
=
6.1 Hz)].
Complex 10 also undergoes a 1,4-addition reaction to the
ynone 26. The corresponding seven-membered metallacyclic
Zr-enolate product (27) was isolated in 55% yield. It was
characterized by X-ray diffraction (see Figure 11). The
+
FLP-Like Reactions of Complex 10 with Conjugated
Enones and Ynones. Some intramolecular frustrated Lewis
pairs show a high tendency to undergo kinetically controlled
structure confirms the selective Zr /P 1,4-addition reaction
(Zr1−O1 2.313(2) Å, P1−C4 1.806(3) Å). The enolate shows
coordination of the central C carbon atom to the
zirconium atom. (C4−C5 1.330(4) Å, C5−C6 1.413(4) Å,
C6−O1 1.276(3) Å, C5−Zr1 2.382(3) Å, angles P1−C4−C5
109.9(2)°, C4−C5−C6 135.2(2)°, C5−C6−O1 112.2(2)°,
dihedral angles C7−C4−C6−C61 48.1°, P1−C4−C6−O1
64.9°) (see Scheme 7). The Zr1−C1 bond (2.509(2) Å) in
the resonance hybrid 27/27′ is rather long (C1−C2 1.357(3)
Å, C1−P1 1.808(3) Å).
27
selective 1,4-addition reactions to conjugated enynes and
2
8
+
ynones. If the Zr /P system 10 could show a similar behavior,
this might serve as an indication for 10 featuring some FLP
+
characteristics. We, therefore, reacted the geminal Zr /P pair
1
0 with selected conjugated enones and ynones.
Complex 10 reacted with the enone 24a at room
temperature to give the 1,4-addition product 25a cleanly. The
product was isolated in 69% yield. It was characterized by X-ray
diffraction using single crystals that were grown from a
dichloromethane solution layered with cyclopentane. The
addition product features a seven-membered metallacyclic
core structure that has the former carbonyl oxygen atom
bonded to zirconium (Zr1−O1 1.985(2) Å). This oxygen atom
is now part of an endocyclic zirconium enolate structure (O1−
CONCLUSIONS
■
Frustrated Lewis pair chemistry at the beginning seemed to be
rather simple: neutralizing adduct formation between the Lewis
acid and base components was hindered by steric bulk. This
resulted in situations of coexistent free Lewis acids and Lewis
bases in solution that could then either react independently or
6
470
dx.doi.org/10.1021/ja3110076 | J. Am. Chem. Soc. 2013, 135, 6465−6476

Journal of the American Chemical Society
Article
reactions of 10. The reactions of 10 with dihydrogen seem to
be different. Here we assume FLP-like behavior of the
frustrated Zr+ Lewis acid/phosphane Lewis base pair that
eventually leads to heterolytic splitting of dihydrogen and its
subsequent follow-up reactions. In some such sequences
+
26
eventually [Cp* ZrH] (or a stabilized form thereof) is
2
formed, a species that then is probably responsible for the
observed catalytic hydrogenation reactions. That means that
the initiation of these reaction sequences is to be regarded as
typical FLP chemistry; its subsequent chemistry including the
catalytic hydrogenation reactions may not (although we have
found some phosphane influence on the catalytic hydro-
genation reaction).
The scale is tipped completely to the FLP reactivity side in
+
the reactions of the Zr /P pair 10 with carbon dioxide, with the
isocyanate, and with mesityl azide, which gives rise to the
formation of typical FLP addition products analogous to what
1
4,15,32
has been observed for, e.g., many B/P pairs.
The FLP
behavior of 10 is found similarly pronounced in the reactions
with conjugated enones and ynones which give similar
products, as they are observed in typical main group element
Figure 11. Molecular structure of the compound 27 (only the cation is
shown).
28
FLPs with such substrates. Our study shows that FLP
chemistry is rapidly expanding also to organometallic chemistry,
but that at the same time the reaction behavior of such systems
is becoming more diverse and complex.
Scheme 7
EXPERIMENTAL SECTION
■
Preparation of complex 11a. Caution: Isocyanides Are Toxic
t
and Must Handled with Due Care. BuNC (1.1 mg, 13.6 μmol) was
added to a solution of complex 10 (19.2 mg, 13.6 μmol) in CH Cl (1
2
2
mL). The color of the reaction mixture became pale yellow
immediately. Then it was covered with cyclopentane (3 mL). After
several days, complex 11a was obtained as a pale yellow crystalline
solid (15.0 mg, 74% yield). Crystals suitable for X-ray single crystal
analysis were grown from a two-layer procedure using CH Cl /
2
2
cyclopentane at −35 °C. Elemental Analysis: calcd. for
C H BF NPZr · CH Cl : C, 56.47; H, 3.94; N, 0.93. Found: C,
7
0
57
20
2
2
−1 1
5
(
6.27; H, 3.88; N, 1.31. IR (KBr): 2178 (s, NC) cm . H NMR
500 MHz, CD Cl , 299 K): δ = 7.41 (m, 2H, o-Ph), 7.35 (m, 3H,
2
2
m,p-Ph), 7.32 (m, 2H, p-Ph P), 7.21 (m, 4H, m-Ph P), 7.14 (m, 4H, o-
2
2
jointly with added substrates. These cooperative reactions
opened pathways to unprecedented chemical behavior and new
reactions, the most prominent being the metal-free splitting and
activation of dihydrogen and the utilization of that feature for
developing novel metal-free catalytic hydrogenation processes
for a variety of specific substrates. In addition, we have seen
more and more addition and activation reactions by FLPs that
have led to new exciting chemical developments.
t
Ph P), 2.58 (s, 3H, Me), 1.79 (s, 30H, C Me ), 1.77 (s, 9H, Bu).
2
5
5
1
3
1
2
C{ H} NMR (126 MHz, CD Cl , 299 K): δ = 169.4 (d, J = 17.2
2
2
PC
1
1
Hz, C), 156.3 (d, J = 119.8 Hz, CZr), 148.5 (dm, J ∼ 240
PC
FC
3
1
Hz, C F ), 147.4 (d, J = 8.5 Hz, i-Ph), 138.7 (dm, J ∼ 240 Hz,
6
5
PC
FC
1
2
C
F
), 136.6 (dm, JFC ∼ 240 Hz, C F ), 135.4 (d, JPC = 12.4 Hz, o-
6
5
6 5
1,29
1
4
Ph P), 132.1 (d, J = 22.4 Hz, i-Ph P), 130.6 (d, J = 2.7 Hz, p-
2
PC
2
PC
3
Ph P), 128.7 (m-Ph), 128.43 (d, J = 10.3 Hz, m-Ph P), 128.39 (p-
2
PC
2
4
t
Ph), 128.3 (d, J = 0.7 Hz, o-Ph), 118.0 (C Me ), 60.1 ( Bu), 34.6
d, J = 23.4 Hz, Me), 30.7 (d, J = 1.7 Hz, Bu), 12.4 (C Me ), n.o.
PC
5
5
3
t
(
(
(
2
P
C
5
5
With its rapid development taking place FLP chemistry has
not remained that simple and, consequently, the FLP concept
has not remained that simplistic. A great number of cases have
been disclosed where Lewis acids and bases do show some
interaction, especially in the many intramolecular FLP
31
1
CN, i-C F ). P{ H} NMR (202 MHz, CD Cl , 299 K): δ = −76.5
6
5
2
2
19
ν1/2 ∼ 8 Hz). F NMR (470 MHz, CD Cl , 299 K): δ = −133.1 (br,
2
2
3
F, o-C F ), −163.9 (t, J = 20.3 Hz, 1F, p-C F ), −167.7 (m, 2F, m-
6
5
FF
6 5
11
1
C F ). B{ H} NMR (160 MHz, CD Cl , 299 K): δ = −16.7 (ν
∼
6
5
2
2
1/2
25 Hz).
X-ray Crystal Structure Analysis of Complex 11a. Formula
57BF20NPZr · CH Cl , M = 1510.09, colorless crystal, 0.45 × 0.15
0.04 mm , a = 10.8271(2), b = 17.5768(3), c = 18.7712(3) Å, α =
3c,30
examples,
but nevertheless have served as very potent
frustrated Lewis pair systems in active small molecule addition
and/or activation. We have even encountered examples where
strong but apparently reversible Lewis acid/Lewis base adduct
C
70
H
2
2
3
×
3
1
10.892(1), β = 100.261(1), γ = 92.846(1)°, V = 3259.05(10) Å , ρ
calc
3
−
−1
31
= 1.539 gcm , μ = 0.377 mm , empirical absorption correction
0.848 ≤ T ≤ 0.985), Z = 2, triclinic, space group P1 (No. 2), λ =
.71073 Å, T = 223(2) K, ω and φ scans, 29611 reflections collected
formation precedes FLP reactions. More and more, we
(
0
̅
discover dichotomies in chemical behavior of FLP systems, and
+
our organometallic Zr /P system described here seems to be a
−1
(
0
±h, ±k, ±l), [(sin θ)/λ] = 0.60 Å , 15649 independent (R
=
int
prominent example. Complex 10 is a coordinatively unsatu-
rated group 4 metallocene system and in many cases it just acts
as such. It adds isonitriles or a nitrile without affecting the
.056) and 12463 observed reflections [I > 2σ(I)], 898 refined
2
parameters, R = 0.078, wR = 0.197, max. (min.) residual electron
density 1.23 (−0.95) e.Å , hydrogen atoms were calculated and
refined as riding atoms.
−
3
13
adjacent Zr−P linkage; no FLP behavior is visible in these
6
471
dx.doi.org/10.1021/ja3110076 | J. Am. Chem. Soc. 2013, 135, 6465−6476

Journal of the American Chemical Society
Article
−
3
Preparation of Complex 11b. Following the procedure described
for the preparation of 11a: reaction of complex 10 (25.5 mg, 18.1
μmol) with BuNC (1.5 mg, 18.1 μmol) gave 11b as a pale yellow
density 2.21 (−0.84) e.Å , hydrogen atoms were calculated and
refined as riding atoms.
n
Preparation of Complex 12. A solution of complex 10 (22.4 mg,
crystalline solid (20.5 mg, 80% yield). Elemental Analysis: calcd. for
15.8 μmol) in 1 mL of CH Cl was degassed and N O (1.5 bar) was
2 2 2
C H BF NPZr · CH Cl · C H : C, 57.76; H, 4.40; N, 0.89. Found:
introduced to the evacuated reaction flask for 10 min. The reaction
mixture was then covered with cyclopentane (4 mL) to give yellow
crystals of 12 (12.8 mg, 59% yield). Crystals suitable for X-ray single
70
57
20
2
2
5
10
−1 1
C, 57.48; H, 4.17; N, 1.07. IR (KBr): 2191 (s, NC) cm . H NMR
(
500 MHz, CD Cl , 299 K): δ = 7.44 (m, 2H, o-Ph), 7.35 (m, 3H,
2
2
m,p-Ph), 7.33 (m, 2H, p-Ph P), 7.22 (m, 4H, m-Ph P), 7.13 (m, 4H, o-
crystal analysis were grown from a two layer procedure using CH
cyclopentane at −35 °C. Elemental Analysis: calcd. for
C H48BF20OPZr: C, 57.49; H, 3.56. Found: C, 56.47; H, 4.14. IR
65
2 2
Cl /
2
2
Bu
Ph P), 4.07 (m, 2H, NCH ), 2.59 (s, 3H, Me), 1.99 (m, 2H, CH2),
2
2
3
1
.77 (s, 30H, C Me ), 1.60 (m, 2H, CH CH ), 1.04 (t, J = 7.4 Hz,
H, CH3). C{ H} NMR (126 MHz, CD Cl , 299 K): δ = 169.2 (d,
5
5
2
3
HH
Bu
13
1
−1 1
3
(KBr): 1643 (m), 1594 (w), 1514 (s), 1464 (s), 980 (s) cm . H
2
2
2
1
1
NMR (500 MHz, CD Cl , 299 K): δ = 7.52 (m, 2H, p-Ph P), 7.41 (m,
JPC = 17.5 Hz, C), 159.9 (br, NC) , 156.3 (d, J = 119.6 Hz, 
2
2
2
PC
1
3
2H, o-Ph), 7.38 (m, 3H, m,p-Ph), 7.36 (m, 4H, m-Ph P), 7.30 (m, 4H,
CZr), 148.6 (dm, J ∼ 240 Hz, C F ), 147.3 (d, J = 8.3 Hz, i-Ph),
2
FC
6
5
PC
4
1
1
o-Ph P), 2.18 (d, J = 0.96 Hz, 3H, Me), 1.96 (s, 30H, C Me ).
1
1
1
38.6 (dm, J ∼ 240 Hz, C F ), 136.6 (dm, J ∼ 245 Hz, C F ),
2
PH
5
5
FC
6
5
FC
6 5
1
3
1
2
2
1
C{ H} NMR (126 MHz, CD Cl , 299 K): δ = 169.4 (d, J = 3.2
35.2 (d, J = 12.2 Hz, o-Ph P), 131.9 (d, J = 22.5 Hz, i-Ph P),
2 2 PC
PC
2
PC
2
t
1
t
1
4
3
Hz, C) , 156.7 (d, J = 9.6 Hz, CZr) , 148.5 (dm, J ∼ 245
6 5 PC FC
30.6 (d, J = 2.8 Hz, p-Ph P), 128.7 (m-Ph), 128.6 (d, J = 10.4
Hz, m-Ph P), 128.4 (p-Ph), 128.2 (d, J = 1.0 Hz, o-Ph), 118.0
PC
FC
PC
2
PC
3
t
1
4
Hz, C F ), 145.2 (d, J = 15.6 Hz, i-Ph) , 138.6 (dm, J ∼ 245 Hz,
2
PC
1
4
3
C F ), 136.7 (dm, J ∼ 240 Hz, C F ), 133.3 (d, J = 3.0 Hz, p-
(
C Me ), 124.3 (br, i-C F ), 45.6 (NCH ), 34.6 (d, J = 23.4 Hz,
6
5
FC
6
5
PC
5
5
6
5
2
PC
2
1
Bu
Bu
1
Ph P), 132.7 (d, J = 12.2 Hz, o-Ph P), 131.8 (d, J = 86.4 Hz, i-
Me), 31.3 ( CH ), 20.5 (CH CH ), 13.3 ( CH ), 12.3 (C Me ). [
from the ghmbc experiment]. P{ H} NMR (202 MHz, CD Cl , 299
2 PC 2 PC
2
2
3
3
5
5
t
t
3
3
1
1
Ph P) , 129.3 (m-Ph), 129.2 (p-Ph) , 128.7 (d, J = 13.2 Hz, m-
2 PC
2
2
4
19
Ph P), 127.9 (d, J = 1.6 Hz, o-Ph), 127.4 (C Me ), 124.7 (br, i-
K): δ = −76.1 (ν ∼ 8 Hz). F NMR (470 MHz, CD Cl , 299 K): δ
2 PC 5 5
1/2
2
2
3
t
3
C F ), 35.2 (d, JPC = 34.6 Hz, Me), 12.4 (C Me ), [ tentative
6 5 5 5
assignment]. P{ H} NMR (202 MHz, CD Cl , 299 K): δ = 17.4
=
−
−133.1 (br, 2F, o-C F ), −163.8 (t, J = 20.3 Hz, 1F, p-C F ),
6
5
FF
6 5
3
1
1
1
1
1
167.7 (m, 2F, m-C F ). B{ H} NMR (160 MHz, CD Cl , 299 K):
2 2
6
5
2
2
1
9
(
2
ν1/2 ∼ 2 Hz). F NMR (470 MHz, CD Cl , 299 K): δ = −133.1 (br,
δ = −16.7 (ν ∼ 25 Hz).
X-ray Crystal Structure Analysis of Complex 11b. Formula
C H BF NPZr · C H , M = 1495.30, colorless crystal, 0.28 × 0.18
2
2
1
/2
3
F, o-C F ), −163.8 (t, J = 20.3 Hz, 1F, p-C F ), −167.7 (m, 2F, m-
6
5
FF
6 5
11 1
C F ). B{ H} NMR (160 MHz, CD Cl , 299 K): δ = −16.7 (ν
∼
6
5
2
2
1/2
7
0
57
20
5
10
3
25 Hz).
×
1
0.12 mm , a = 14.2433(1), b = 32.5730(3), c = 15.0069(2) Å, β =
3
−3
X-ray Crystal Structure Analysis of Complex 12. Formula
03.477(1) °, V = 6770.69(12) Å , ρ = 1.467 gcm , μ = 0.286
calc
1
−
C H BF OPZr · C H , M = 1428.16, yellow crystal, 0.20 × 0.12 ×
6
5
48
20
5
10
mm , empirical absorption correction (0.924 ≤ T ≤ 0.966), Z = 4,
3
0
8
.03 mm , a = 10.6759(2), b = 15.4536(3), c = 19.3351(5) Å, α =
4.321(1), β = 82.779(2), γ = 83.515(2)°, V = 3132.73(12) Å , ρ
monoclinic, space group P2 /c (No. 14), λ = 0.71073 Å, T = 223(2) K,
1
3
=
calc
ω and φ scans, 44278 reflections collected (±h, ±k, ±l), [(sin θ)/λ] =
−
3
−1
−
1
1.514 gcm , μ = 0.306 mm , empirical absorption correction (0.941
≤ T ≤ 0.990), Z = 2, triclinic, space group P1 (No. 2), λ = 0.71073 Å,
T = 223(2) K, ω and φ scans, 32038 reflections collected (±h, ±k, ±l),
0
.60 Å , 11597 independent (R = 0.054) and 9833 observed
int
2
̅
reflections [I > 2σ(I)], 960 refined parameters, R = 0.047, wR = 0.108,
max. (min.) residual electron density 0.43 (−0.39) e.Å , hydrogen
atoms calculated and refined as riding atoms.
−3
−
1
[
(sin θ)/λ] = 0.59 Å , 10726 independent (R = 0.052) and 8666
int
observed reflections [I > 2σ(I)], 904 refined parameters, R = 0.087,
Preparation of Complex 11c. Following the procedure described
for the preparation of 11a: reaction of complex 10 (30.7 mg, 21.7
2
−3
wR = 0.242, max. (min.) residual electron density 2.92 (−0.69) e.Å ,
t
hydrogen atoms calculated and refined as riding atoms.
μmol) with BuCN (1.8 mg, 21.7 μmol) gave 11c as a pale yellow
Preparation of Complex 13. Caution: Isocyanates Are Toxic
crystalline solid (22.5 mg, 69% yield). Crystals suitable for X-ray single
crystal analysis were grown from a two layer procedure using CH Cl /
t
and Must Handled with Due Care. BuNCO (1.4 mg, 14.2 μmol) was
2
2
added to a solution of complex 10 (20.0 mg, 14.2 μmol) in CH Cl (1
2
2
cyclopentane at −35 °C. Elemental Analysis: calcd. for
mL), and then the reaction mixture was covered with pentane (3 mL).
After several days a beige oil was formed. The solvent was decanted
and the obtained residue was stirred in pentane (5 mL). The obtained
precipitate was collected and then washed with pentane (3*2 mL) to
give complex 13 as a yellow solid (16.0 mg, 79% yield). Crystals
suitable for X-ray single crystal analysis were grown from a two layer
procedure using CH Cl /cyclopentane at −35 °C. Elemental Analysis:
C H BF NPZr · CH Cl : C, 56.47; H, 3.94; N, 0.93. Found: C,
7
0
57
20
2
2
−
1 1
5
(
5.10; H, 3.79; N, 0.60. IR (KBr): 2261 (m, NC) cm . H NMR
600 MHz, CD Cl , 299 K): δ = 7.40 (m, 2H, o-Ph), 7.34 (m, 3H,
2
2
m,p-Ph), 7.31 (m, 2H, p-Ph P), 7.20 (m, 4H, m-Ph P), 7.09 (m, 4H, o-
2
2
t
Ph P), 2.47 (s, 3H, Me), 1.79 (s, 30H, C Me ), 1.65 (br, 9H, Bu).
C{ H} NMR (151 MHz, CD Cl , 299 K): δ = 168.6 (d, J = 15.2
2
5
5
1
3
1
2
2
2
PC
2
2
1
1
Hz, C), 163.1 (d, J = 119.0 Hz, CZr), 148.5 (dm, J ∼ 245
PC
FC
calcd. for C H BF NOPZr: C, 58.34; H, 3.99; N, 0.97. Found: C,
70 57 20
3
−1 1
Hz, C F ), 147.3 (d, J = 9.1 Hz, i-Ph), 141.4 (br, CN), 138.7 (dm,
6
5
PC
58.57; H, 4.28; N, 1.01. IR (KBr): 1641 (s, CN) cm . H NMR
1
1
2
JFC ∼ 250 Hz, C F ), 136.6 (dm, J ∼ 250 Hz, C F ), 135.4 (d, J
12.6 Hz, o-Ph P), 132.9 (d, J = 18.8 Hz, i-Ph P), 130.4 (d, J
.6 Hz, p-Ph P), 128.7 (m-Ph), 128.40 (d, J = 10.6 Hz, m-Ph P),
28.36 (d, J = 0.8 Hz, o-Ph), 128.3 (p-Ph), 124.5 (br, i-C F ), 119.7
(600 MHz, CD Cl , 299 K): δ = 7.60 (m, 2H, p-Ph P), 7.47 (m, 4H, o-
6
5
FC
6
5
PC
2
2
2
1
4
=
2
1
(
(
=
Ph P), 7.40 (m, 4H, m-Ph P), 7.09 (m, 1H, p-Ph), 6.93 (m, 2H, m-
2
PC
2
PC
2
2
3
2
PC
2
Ph), 6.79 (m, 2H, o-Ph), 2.02 (s, 30H, C Me ), 1.71 (s, 3H, Me), 1.26
5 5
4
t
13
1
(s, 9H, Bu). C{ H} NMR (151 MHz, CD Cl , 299 K): δ = 174.5 (d,
PC
6
5
2 2
3
t
t
2
1
1
C Me ), 34.6 (d, J = 22.4 Hz, Me), 30.6 ( Bu), 28.3 ( Bu), 12.5
JPC = 6.4 Hz, C), 158.5 (d, J = 18.5 Hz, CZr), 151.3 (d, J
=
=
∼
5
5
PC
PC
PC
PC
FC
3
1
1
1
3
C Me ). P{ H} NMR (243 MHz, CD Cl , 299 K): δ = −64.8 (ν
158.5 Hz, CN), 148.5 (dm, J ∼ 245 Hz, C F ), 143.2 (d, J
5
5
2
2
1/2
FC
6 5
1
9
1
1
∼
3 Hz). F NMR (564 MHz, CD Cl , 299 K): δ = −133.2 (br, 2F, o-
14.7 Hz, i-Ph), 138.6 (dm, J ∼ 245 Hz, C F ), 136.7 (dm, J
2
2
FC
6 5
3
2
4
C F ), −163.9 (t, J = 20.3 Hz, 1F, p-C F ), −167.7 (m, 2F, m-
245 Hz, C F ), 134.2 (d, J = 9.8 Hz, o-Ph P), 133.5 (d, J = 2.9
6
5
FF
6
5
6
5
PC
2
PC
1
1
1
3
C F ). B{ H} NMR (192 MHz, CD Cl , 299 K): δ = −16.7 (ν
∼
Hz, p-Ph P), 129.0 (d, J = 11.9 Hz, m-Ph P), 128.7 (m-Ph), 128.2
(p-Ph), 127.5 (d, J = 1.3 Hz, o-Ph), 127.1 (d, J = 68.8 Hz, i-
PC PC
Ph P), 126.5 (C Me ), 123.9 (br, i-C F ), 57.1 (d, J = 18.3 Hz,
Bu), 37.7 (d, JPC = 31.7 Hz, Me), 30.9 ( Bu), 12.7 (C Me ).[
6
5
2
2
1/2
2 PC 2
4
1
3
0 Hz).
X-ray Crystal Structure Analysis of Complex 11c. Formula
C H BF NPZr · CH Cl , M = 1510.09, pale yellow crystal, 0.33 ×
3
2
5
5
6
5
PC
t
3
t
t
7
0
57
20
2
2
5
5
3
31
1
0
=
=
(
0
.04 × 0.03 mm , a = 10.8445(2), b = 17.5706(3), c = 18.7237(3) Å, α
110.727(1), β = 100.205(1), γ = 92.786(7)°, V = 3259.9(1) Å , ρ
tentatively assigned]. P{ H} NMR (243 MHz, CD Cl , 299 K): δ =
2 2
3
19
calc
33.7 (ν1/2 ∼ 5 Hz). F NMR (564 MHz, CD Cl , 299 K): δ = −133.1
2
2
−
3
−1
3
1.538 gcm , μ = 0.377 mm , empirical absorption correction
(No. 2), λ =
.71073 Å, T = 223(2) K, ω and φ scans, 31273 reflections collected
(br, 2F, o-C F ), −163.9 (t, J = 20.3 Hz, 1F, p-C F ), −167.7 (m,
6
5
FF
6 5
11 1
0.885 ≤ T ≤ 0.988), Z = 2, triclinic, space group P1
̅
2F, m-C F ). B{ H} NMR (192 MHz, CD Cl , 299 K): δ = −16.7
6
5
2
2
(ν1/2 ∼ 20 Hz).
−
1
(
±h, ±k, ±l), [(sin θ)/λ] = 0.62 Å , 15923 independent (R
=
X-ray Crystal Structure Analysis of Complex 13. Formula
C H BF NOPZr · CH Cl , M = 1526.09, yellow crystal, 0.33 × 0.10
int
0
.048) and 12431 observed reflections [I > 2σ(I)], 916 refined
70
57
20
2
2
2
3
parameters, R = 0.075, wR = 0.171, max. (min.) residual electron
× 0.03 mm , a = 10.7932(3), b = 18.4658(5), c = 19.7558(6) Å, α =
6
472
dx.doi.org/10.1021/ja3110076 | J. Am. Chem. Soc. 2013, 135, 6465−6476

Journal of the American Chemical Society
Article
3
3
1
1
≤
05.168(1), β = 99.567(1), γ = 92.603(2)°, V = 3731.02(18) Å , ρ
=
−163.9 (t, J = 20.3 Hz, 1F, p-C F ), −167.7 (m, 2F, m-C F ).
calc
FF
6
5
6 5
−3
−1
11 1
.358 gcm , μ = 0.331 mm , empirical absorption correction (0.898
T ≤ 0.990), Z = 2, triclinic, space group P1 (No. 2), λ = 0.71073 Å,
T = 223(2) K, ω and φ scans, 33362 reflections collected (±h, ±k, ±l),
(sin θ)/λ] = 0.60 Å , 12817 independent (R = 0.064) and 10366
observed reflections [I > 2σ(I)], 925 refined parameters, R = 0.077,
wR = 0.197, max. (min.) residual electron density 0.81 (−0.62) e.Å ,
hydrogen atoms were calculated and refined as riding atoms.
Preparation of Complex 14. A solution of complex 10 (37.0 mg,
B{ H} NMR (160 MHz, CD Cl , 299 K): δ = −16.7 (ν ∼ 20 Hz).
2
2
1/2
̅
X-ray Crystal Structure Analysis of Complex 15. Formula
C H BF N PZr · C H , M = 1573.37, yellow-orange crystal, 0.28 ×
74
59
20
3
5
10
−1
3
[
0.17 × 0.08 mm , a = 40.5492(6), b = 14.9195(2), c = 24.7606(4) Å, β
int
3
−3
= 99.432(1)°, V = 14777.0(4) Å , ρ = 1.414 gcm , μ = 0.267
calc
2
−3
−1
mm , empirical absorption correction (0.929 ≤ T ≤ 0.979), Z = 8,
monoclinic, space group C2/c (No. 15), λ = 0.71073 Å, T = 223(2) K,
ω and φ scans, 47775 reflections collected (±h, ±k, ±l), [(sin θ)/λ] =
−1
2
6.2 μmol) in CH Cl (1 mL) was degassed and CO (1 bar) was
0.67 Å , 12838 independent (R = 0.041) and 10528 observed
reflections [I > 2σ(I)], 960 refined parameters, R = 0.047, wR = 0.123,
max. (min.) residual electron density 0.39 (−0.36) e.Å , hydrogen
atoms calculated and refined as riding atoms.
Reaction of Complex 10 with H (D ) (in CH Cl ). A solution of
complex 10 (28.2 mg, 20.0 μmol) in CH Cl (2 mL) was degassed and
H (1.5 bar) was introduced to the evacuated reaction flask for 2 h.
Then the reaction mixture was covered with pentane (4 mL) to give a
2
2
2
int
2
introduced to the evacuated reaction flask at 0 °C for 5 min. After
warming to room temperature, the reaction mixture was covered with
pentane (3 mL) to eventually gave complex 14 as a yellow solid (28.0
mg, 77% yield). Crystals suitable for X-ray single crystal analysis were
grown from a two layer procedure using CH Cl /cyclopentane at −35
−3
2
2
2
2
2
2
2
2
°
3
C. Elemental Analysis: calcd. for C H BF O PZr: C, 57.19; H,
66
48
20
2
2
−1 1
.49. Found: C, 57.25; H, 3.36. IR (KBr): 1699 (s, CO) cm . H
NMR (500 MHz, CD Cl , 299 K): δ = 7.66 (m, 2H, p-Ph P), 7.47 (m,
white crystalline solid (16 mg, 55% yield 19/20) (suitable for X-ray
2
2
2
4
H, m-Ph P), 7.39 (m, 4H, o-Ph P), 7.17 (m, 1H, p-Ph), 7.01 (m, 2H,
crystal structure analysis). The solid was identified as a mixture of
2
2
4
1
m-Ph), 6.88 (m, 2H, o-Ph), 2.01 (s, 30H, C Me ), 1.71 (d, J = 0.6
Hz, 3H, Me). C{ H} NMR (126 MHz, CD Cl , 299 K): δ = 175.8
Cp*
Data of Cp*
1.97 (s, 30H, C
124.2 (C Me
MHz, CD Cl , 299 K): δ = 7.81 (m, 2H, p-Ph P), 7.62 (m, 4H, m-
2
ZrCl
2
(19) and compound 20 (ratio: 1:6, H NMR) in CD
2
Cl
, 299 K): δ =
Cl , 299 K): δ =
2
.
5
5
PH
1
3
1
1
ZrCl
(19): H NMR (600 MHz, CD
5
Cl
). C{ H} NMR (151 MHz, CD
2
2
2
2
2
2
2
2
1
13
1
(
d, J = 7.2 Hz, C), 165.5 (d, J = 125.1 Hz, (O)CO), 155.7 (d,
5
Me
2
PC
PC
1
1
1
JPC = 27.0 Hz, CZr), 148.5 (dm, J ∼ 240 Hz, C F ), 142.9 (d,
1J ∼ 240 Hz, C F ), 134.4 (d, J = 3.1 Hz, p-Ph P), 133.9 (d, J
5
5 5 5
), 12.1 (C Me ). Data of complex 20: H NMR (600
FC
6 5
3
1
JPC = 15.1 Hz, i-Ph), 138.6 (dm, J ∼ 230 Hz, C F ), 136.6 (dm,
2
2
2
FC
6 5
4
2
Ph P), 7.54 (m, 4H, o-Ph P), 7.26 (m, 1H, p-Ph), 7.10 (m, 2H, m-Ph),
2
2
FC
6
5
PC
2
PC
2
4
3
6.84 (m, 2H, o-Ph), 6.30 (dq, J = 21.8 Hz, J = 1.4 Hz, 1H, 
CH), 4.03 (d, J = 5.8 Hz, 2H, ClCH ), 2.58 (dd, J = 1.4 Hz, J
PH 2 HH PH
PH
HH
=
9.9 Hz, o-Ph P), 129.7 (d, J = 11.9 Hz, m-Ph P), 129.0 (m-Ph),
2 PC 2
2
4
4
4
1
28.9 (p-Ph), 127.5 (C Me ), 127.3 (d, J = 1.7 Hz, o-Ph), 124.8 (d,
5 5 PC
13
1
1
3
= 1.0 Hz, 3H, Me). C{ H} NMR (151 MHz, CD
2
Cl
2
, 299 K): δ =
JPC = 65.1 Hz, i-Ph P), n.o. (i-C F ), 37.3 (d, J = 32.9 Hz, Me),
2
6
5
PC
2
1
3
1
1
176.7 (d, JPC = 1.6 Hz, C), 148.6 (dm, JFC ∼ 245 Hz, C
6
F
5
), 138.5
12.5 (C Me ). P{ H} NMR (202 MHz, CD Cl , 299 K): δ = 27.6
5
5
2
2
1
3
1
9
(dm, JFC ∼ 245 Hz, C
6
F
5
), 138.2 (d, JPC = 7.2 Hz, i-Ph), 136.5 (dm,
(
2
ν1/2 ∼ 2 Hz). F NMR (470 MHz, CD Cl , 299 K): δ = −133.1 (br,
2
2
1
4
2
3
J
FC ∼ 245 Hz, C
6
F
5
), 136.3 (d, JPC = 3.1 Hz, p-Ph
2
P), 133.4 (d, JPC
P), 130.87 (d, JPC = 13.1 Hz, m-Ph P), 130.86 (p-
Ph), 129.4 (m-Ph), 126.5 (d, J = 1.5 Hz, o-Ph), 124.4 (br, i-C F ),
F, o-C F ), −163.8 (t, J = 20.3 Hz, 1F, p-C F ), −167.7 (m, 2F, m-
6
5
FF
6
5
3
11 1
= 10.2 Hz, o-Ph
2
2
C F ). B{ H} NMR (160 MHz, CD Cl , 299 K): δ = −16.7 (ν
∼
6
5
2
2
1/2
4
PC
6 5
2
5 Hz).
X-ray Crystal Structure Analysis of Complex 14. Formula
C H BF O PZr, M = 1386.04, yellow crystal, 0.25 × 0.13 × 0.02
1
1
1
3
16.8 (d, J = 89.8 Hz, i-Ph P), 102.0 (d, J = 90.8 Hz, CH),
PC
2
PC
1
3
31
1
5.3 (d, J = 61.4 Hz, ClCH ), 30.9 (d, J = 17.2 Hz, Me). P{ H}
PC 2 PC
66
48
20
2
19
3
NMR (243 MHz, CD
(564 MHz, CD Cl , 299 K): δ = −133.1 (br, 2F, o-C
FF = 20.3 Hz, 1F, p-C
192 MHz, CD Cl , 299 K): δ = −16.7 (ν ∼ 20 Hz).
2
Cl
2
, 299 K): δ = 14.1 (ν1/2 ∼ 2 Hz). F NMR
mm , a = 10.6552(2), b = 16.3512(2), c = 18.5198(3) Å, α =
3
2
2
F
6 5
), −163.8 (t,
9
1
≤
1.707(1), β = 91.971(1), γ = 104.075(1)°, V = 3125.47(9) Å , ρ
=
calc
3
11
1
−3
−1
J
6
F
5
), −167.6 (m, 2F, m-C F ). B{ H} NMR
6 5
.473 gcm , μ = 0.305 mm , empirical absorption correction (0.927
T ≤ 0.993), Z = 2, triclinic, space group P1 (No. 2), λ = 0.71073 Å,
T = 223(2) K, ω and φ scans, 29120 reflections collected (±h, ±k, ±l),
(
2
2
1/2
̅
Under similar conditions as described above the reaction between
1
−1
complex 10 and D gave 19 and 20-D (ratio ca. 1:8, H NMR). Data
2
[
(sin θ)/λ] = 0.60 Å , 10788 independent (R = 0.040) and 9535
int
1
of complex 20-D: H NMR (500 MHz, CD Cl , 299 K): δ = 7.82 (m,
2
2
observed reflections [I > 2σ(I)], 831 refined parameters, R = 0.046,
wR = 0.122, max. (min.) residual electron density 0.43 (−0.35) e.Å ,
hydrogen atoms were calculated and refined as riding atoms.
2
−3
2H, p-Ph
2
P), 7.64 (m, 4H, m-Ph
2
P), 7.54 (m, 4H, o-Ph P), 7.27 (m,
2
2
1
H, p-Ph), 7.11 (m, 2H, m-Ph), 6.84 (m, 2H, o-Ph), 4.03 (d, J = 5.8
Hz, 2H, ClCH ), 2.59 (d, J = 1.0 Hz, 3H, Me). H NMR (77 MHz,
PH
4
2
2
PH
Preparation of Complex 15. MesN (2.1 mg, 13.3 μmol) was
3
CH Cl , 299 K): δ = 6.33 (br, CD).
2
2
added to a solution of complex 10 (18.8 mg, 13.3 μmol) in CH Cl (1
2
2
X-ray Crystal Structure Analysis of Compound 19/20.
mL) at ca. −35 °C. The color of the reaction mixture became red
immediately. The reaction solution was covered with cyclopentane (3
mL) and stored in the fridge (ca. −35 °C) for several days. Complex
Formula C H Cl Zr · C H BF ClP, M = 1463.42, yellow crystal,
2
0
30
2
46 21
20
3
0
1
3
.45 × 0.20 × 0.12 mm , a = 13.9278(5), b = 15.0219(4), c =
6.8483(7) Å, α = 70.762(2), β = 78.877(2), γ = 70.199(2)°, V =
1
5 was obtained as a red crystalline solid (14.6 mg, 70% yield).
3
−3
−1
118.27(19) Å , ρ = 1.559 gcm , μ = 0.432 mm , empirical
calc
Crystals suitable for X-ray single crystal analysis were grown from a
two layer procedure using CH Cl /cyclopentane at −35 °C. Elemental
Analysis: calcd. for C H BF N PZr: C, 59.12; H, 3.96; N, 2.80.
absorption correction (0.829 ≤ T ≤ 0.949), Z = 2, triclinic, space
group P1 (No. 2), λ = 0.71073 Å, T = 223(2) K, ω and φ scans, 23638
reflections collected (±h, ±k, ±l), [(sin θ)/λ] = 0.59 Å , 10412
independent (Rint = 0.037) and 9545 observed reflections [I > 2σ(I)],
2
2
̅
74
59
20
3
−1
−1
Found: C, 58.03; H, 4.19; N, 2.49. IR (KBr): 1609 (w, NN) cm .
1
H NMR (500 MHz, CD Cl , 299 K): δ = 7.61 (m, 2H, p-Ph P), 7.39
2
2
2
2
8
40 refined parameters, R = 0.041, wR = 0.103, max. (min.) residual
(
m, 4H, m-Ph P), 7.32 (m, 4H, o-Ph P), 7.28 (m, 1H, p-Ph), 7.19 (m,
−3
2
2
electron density 0.49 (−0.48) e.Å , hydrogen atoms were calculated
and refined as riding atoms.
2H, m-Ph), 7.09 (m, 2H, o-Ph), 6.81 (m, 2H, m-Mes), 2.22 (s, 3H,
p‑Mes
o‑Mes
CH3
), 2.10 (s, 30H, C Me ), 2.05 (s, 6H, CH
), 2.03 (s, 3H,
23
5
5
3
Reaction of Complex 10 with H (D ) (in C D ). A solution of
Me). 13C{ H} NMR (126 MHz, CD Cl , 299 K): δ = 172.2 (d, J
=
PC
1
2
2
2
6
6
2
2
complex 10 (20.5 mg, 14.5 μmol) in 1 mL of C D (3 drops of THF
1
1
6
6
2
.3 Hz, C), 158.8 (d, J = 8.0 Hz, CZr), 148.5 (dm, J ∼ 240
PC
FC
was added) was degassed and H (1.5 bar) was introduced to the
3
2
Hz, C F ), 144.5 (i-Mes), 144.4 (d, J = 15.8 Hz, i-Ph), 138.6 (dm,
6 5 PC
evacuated reaction flask for 10 min. The reaction mixture was then
covered with pentane (4 mL) to give yellow crystals of 21 (12.0 mg,
52% yield of 21/21-Cl) (see X-ray crystal structure analysis: the σ-
1
1
JFC ∼ 245 Hz, C F ), 138.0 (p-Mes), 136.7 (dm, J ∼ 240 Hz,
6
5
FC
2
4
C F ), 135.2 (d, J = 10.7 Hz, o-Ph P), 134.0 (d, J = 3.0 Hz, p-
6
5
PC
2
PC
3
Ph P), 131.8 (o-Mes), 130.7 (m-Mes), 129.2 (m-Ph), 128.71 (d, J
=
2
PC
ligand site is ca. 25% occupied by chloride [Cp* Zr(THF)Cl][B-
2
1
11.1 Hz, m-Ph P), 128.66 (p-Ph), 128.6 (C Me ), 128.3 (d, J = 71.0
2 5 5 PC
(C F ) ] (21-Cl) probably resulted from traces of CH Cl in the
6
5
4
2
2
4
Hz, i-Ph P), 127.7 (d, J = 1.6 Hz, o-Ph), 124.7 (br, i-C F ), 36.4 (d,
2
PC
6
5
starting material 10). The volatiles of the mother liquid were removed
3
3
1
o‑Mes
p‑Mes
J
= 35.5 Hz, Me), 21.1 (CH3
), 20.8 (CH3
), 13.1 (C Me ).
PC
5 5
in vacuo to get 22 (ca. 6 mg, 83% yield) admixed with 21 and 21-Cl
1
1
1
1
P{ H} NMR (202 MHz, CD Cl , 299 K): δ = 12.3 (ν ∼ 3 Hz).
(85: 10: 5). Data of Complex 21 (21: 21-Cl = 70: 30, H NMR): H
NMR (600 MHz, C D Br, 299 K): δ = 7.73 (s, 1H, ZrH), 3.15 (br,
2
2
1/2
9
F NMR (470 MHz, CD Cl , 299 K): δ = −133.1 (br, 2F, o-C F ),
2
2
6
5
6
5
6
473
dx.doi.org/10.1021/ja3110076 | J. Am. Chem. Soc. 2013, 135, 6465−6476

Journal of the American Chemical Society
Article
α‑THF
), 1.66 (s, 30H, C Me ), 1.54 (br, 4H, CH2β‑THF).
4
O
4
H, CH2
(d, J = 3.2 Hz, i), 129.0 (p), 128.6 (m), 126.7 (o) (Ph ), 138.9 (d,
PC
5
5
1
3
1
1
2
CH
2
C{ H} NMR (151 MHz, C D Br, 299 K): δ = 148.6 (dm, J ∼ 240
JPC = 2.6 Hz, i), 129.9 (o), 129.2 (m), 127.3 (p) (Ph ), 136.0 (d, J
= 7.2 Hz, o), 134.5 (d, J = 3.3 Hz, p), 129.8 (d, J = 4.2 Hz, m),
PC PC
121.8 (d, J = 77.5 Hz, i) (Ph P), 131.5 (d, J = 3.3 Hz, m), 128.2
6
5
FC
PC
1
1
4
3
Hz, C F ), 138.4 (dm, J ∼ 245 Hz, C F ), 136.5 (dm, J ∼ 245
6
5
FC
6
5
FC
α‑THF
1
3
Hz, C F ), 124.7 (br, i-C F ), 123.4 (C Me ), 70.9 (br, CH
),
6
5
6
5
5
5
2
PC 2 PC
β‑THF
19
t
2
4.3 (br, CH2
), 11.3 (C Me ). F NMR (564 MHz, C D Br, 299
(br, p), n.o. (i, o) (Ph P′) , 125.3 (C Me ′), 125.0 (C Me ), 100.7 (d,
5
5
6
5
2
5
5
5
5
3
2
1
3
K): δ = −131.5 (br, 2F, o-C F ), −161.8 (t, J = 21.0 Hz, 1F, p-
J
= 9.7 Hz, HC), 46.3 (d, J = 50.6 Hz, CHPh), 38.9 (d, J
=
PC
6
5
FF
PC
PC
1
1
1
t
C F ), −165.7 (m, 2F, m-C F ). B{ H} NMR (192 MHz, C D Br,
36.7 Hz, Me), 13.4 (C Me ), 12.6 (C Me ′), [C F not listed;
6
5
6
5
6
5
5
5
5
5
6 5
tentative assignment]. 31P{ H} NMR (243 MHz, CD Cl , 299 K): δ
1
2
99 K): δ = −16.0 (ν ∼ 20 Hz). Data of Compound 22 (22: 21: 21-
1/2
2 2
1
1
19
Cl = 85: 10: 5, H NMR): H NMR (600 MHz, C D , 299 K): δ =
= 22.1 (ν1/2 ∼ 2 Hz). F NMR (564 MHz, CD Cl , 299 K): δ =
6
6
2
2
3
7
.46 (m, 4H, o-Ph P), 7.28 (m, 2H, o-Ph), 7.09 (m, 2H, m-Ph), 7.08
−133.2 (br, 2F, o-C F ), −163.9 (t, J = 20.3 Hz, 1F, p-C F ),
2
6
5
FF
6 5
11 1
(
m, 4H, m-Ph P), 7.05 (m, 1H, p-Ph), 7.04 (m, 2H, p-Ph P), 6.32 (dq,
−167.7 (m, 2F, m-C F ). B{ H} NMR (192 MHz, CD Cl , 299 K):
2
2
6
5
2
2
2
4
4
4
JPH = 3.9 Hz, J = 1.4 Hz, 1H, CH), 2.05 (dd, J = 1.4 Hz, J
δ = −16.7 (ν ∼ 25 Hz).
HH
HH
PH
1/2
13
1
=
1
(
(
0.7 Hz, 3H, Me). C{ H} NMR (151 MHz, C D , 299 K): δ =
X-ray Crystal Structure Analysis of Complex 25a. Formula
C H BF OPZr · C H , M = 1620.41, yellow crystal, 0.33 × 0.10 ×
6
6
2
3
54.4 (d, J = 25.7 Hz, C), 141.9 (d, J = 6.7 Hz, i-Ph), 141.3
PC
PC
80 60
20
5
10
1
3
3
d, J = 11.9 Hz, i-Ph P), 133.0 (d, J = 19.0 Hz, o-Ph P), 128.7
0.07 mm , a = 13.9073(2), b = 14.3933(2), c = 19.6665(3) Å, α =
72.517(1), β = 85.337(1), γ = 77.455(1)°, V = 3664.64(9) Å , ρ
1.468 gcm , μ = 0.271 mm , empirical absorption correction (0.915
≤ T ≤ 0.981), Z = 2, triclinic, space group P1 (No. 2), λ = 0.71073 Å,
T = 223(2) K, ω and φ scans, 33878 reflections collected (±h, ±k, ±l),
PC 2 PC 2
3
4
3
d, J = 6.2 Hz, m-Ph P), 128.4 (d, J = 4.7 Hz, o-Ph), 128.3 (p-
=
PC
2
PC
calc
1
−3
−1
Ph P), 128.1 (m-Ph), 127.9 (p-Ph), 126.4 (d, J = 11.6 Hz, CH),
2
PC
3
31
1
2
7.6 (d, J = 6.0 Hz, Me). P{ H} NMR (243 MHz, C D , 299 K):
̅
PC
6
6
δ = −25.0 (ν1 ∼ 2 Hz).
/2
−1
Under similar conditions as described above the reaction between
[(sin θ)/λ] = 0.59 Å , 12687 independent (R = 0.045) and 10908
int
complex 10 and D gave 21-D and 22-D. Data of complex 21-D (21-D:
observed reflections [I > 2σ(I)], 1039 refined parameters, R = 0.052,
wR = 0.121, max. (min.) residual electron density 0.46 (−0.42) e.Å ,
hydrogen atoms calculated and refined as riding atoms.
2
1
1
2
−3
2
1-Cl = 84: 16, H NMR): H NMR (500 MHz, C D Br, 299 K): δ =
6
5
α‑THF
3.15 (br, 4H, CH
), 1.66 (s, 30H, C Me ), 1.54 (br, 4H,
2
5 5
β‑THF
2
CH2
). H NMR (77 MHz, C H Br, 299 K): δ = 7.70 (s, ZrD).
Preparation of Complex 25b. Following the procedure described
for the preparation of 25a: reaction of complex 10 (21.7 mg, 15.4
μmol) with 1,2,3-triphenylprop-2-en-1-one (4.4 mg, 15.4 μmol) gave
25b as a pale yellow crystalline solid (20.2 mg, 77% yield). Crystals
suitable for X-ray single crystal analysis were grown from a two layer
procedure using CH Cl /cyclopentane at −35 °C. Elemental Analysis:
6
5
1
Data of 22-D: H NMR (500 MHz, CD Cl , 299 K): δ = 7.39 (m, 4H,
2
2
4
o-Ph P), 7.34 −7.30 (m, 9H, Ph), 7.26 (m, 2H, p-Ph P), 2.33 (d J
=
2
2
PH
2
0.6 Hz, 3H, Me). H NMR (77 MHz, CH Cl , 299 K): δ = 6.34 (br,
2 2

CD).
X-ray Crystal Structure Analysis of Compound 21. Formula
2
2
C H BCl0.25F20OZr, M = 1122.43, yellow crystal, 0.23 × 0.05 ×
calcd. for C H BF OPZr · C H : C, 64.42; H, 4.40. Found: C,
48
38.75
86 64 20 5 10
3
0
7
1
.03 mm , a = 10.8133(2), b = 14.3998(2), c = 15.2987(4) Å, α =
64.48; H, 5.03. IR (KBr): 1643 (m), 1588 (w), 1513 (s), 1464 (s), 979
3
−1 1
7.974(1), β = 86.094(1), γ = 83.647(1)°, V = 2313.07(8) Å , ρ
=
(s) cm . H NMR (500 MHz, CD Cl , 299 K): δ = 8.39 (2H, o), 8.07
calc
2 2
−3
−1
.612 gcm , μ = 0.370 mm , empirical absorption correction (0.919
T ≤ 0.989), Z = 2, triclinic, space group P1 (No. 2), λ = 0.71073 Å,
T = 223(2) K, ω and φ scans, 21051 reflections collected (±h, ±k, ±l),
(1H, p), 8.00 (2H, m) (each m, Ph), 7.59, 7.19, 6.77, 6.18, 5.68 (each
br m, each 1H, Ph), 7.05 (3H, m,p), 6.94 (2H, o) (each m, Ph), 6.86
(br), 6.81 (m, 1H), 6.53 (m), 6.52 (m), 5.78 (br) (each 1H, Ph), 6.85,
≤
̅
−1
[
(sin θ)/λ] = 0.67 Å , 8023 independent (R = 0.043) and 6815
6.74, 6.45, 6.42, 5.87 (each m, each 1H, Ph), n.o. (br, 3H), 6.62 (1H),
int
2
observed reflections [I > 2σ(I)], 663 refined parameters, R = 0.055,
6.39 (1H) (each br, Ph), 5.98 (d, J = 21.2 Hz, 1H, CHPh), 2.34 (s,
PH
2
−3
13
1
wR = 0.115, max. (min.) residual electron density 0.34 (−0.43) e.Å ,
hydrogen atoms were calculated and refined as riding atoms. Comment:
the σ-ligand site is ca. 25% occupied by chloride; the remaining 75% of
that site seem to be occupied by hydride.
15H, C Me ), 1.83 (br, 3H, Me), 1.75 (s, 15H, C Me ′). C{ H}
5
5
5
5
NMR (126 MHz, CD Cl , 299 K)[selected resonances]: δ = 172.2 (d,
2
2
2
3
1
JPC = 7.6 Hz, C), 159.0 (d, J = 7.1 Hz, OC), 157.1 (d, J
=
PC
PC
38.2 Hz, CZr), 145.2 (i-Ph), 125.3 (C Me ′), 125.1 (C Me ), 110.2
5
5
5
5
2
1
General Procedure of the Catalytic Hydrogenation. Com-
pound 10, substrate (0.5 mmol), and ferrocene (9.3 mg, 50 μmol) as
standard compound were dissolved in C D Br (1 mL). Then the
(d, J = 8.3 Hz, PhC), 51.3 (d, J = 50.7 Hz, CHPh), 38.8 (d,
PC
PC
3
31
1
JPC = 37.0 Hz, Me), 13.6 (C Me ), 12.8 (C Me ′). P{ H} NMR
5 5 5 5
1
9
6
5
(202 MHz, CD Cl , 299 K): δ = 26.6 (ν ∼ 1 Hz). F NMR (470
2
2
1/2
3
reaction mixture was frozen and evacuated, then H (1.5 bar, r.t.) was
2
MHz, CD Cl , 299 K): δ = −133.1 (br, 2F, o-C F ), −163.9 (t, J
=
FF
2
2
6
5
1
1
1
introduced for the respective reaction time. Subsequently the reaction
2
0.4 Hz, 1F, p-C F ), −167.7 (m, 2F, m-C F ). B{ H} NMR (160
6
5
6 5
1
solution was transferred to an NMR tube and monitored by H NMR.
MHz, CD Cl , 299 K): δ = −16.7 (ν ∼ 25 Hz).
2
2
1/2
The NMR yield was determined relative to ferrocene as internal
standard.
Preparation of Complex 25a. A solution of complex 10 (19.5
X-ray Crystal Structure Analysis of Complex 25b. Formula
C H BF OPZr · C H , M = 1696.50, pale yellow crystal, 0.20 ×
86
64
20
5
10
3
0
.10 × 0.02 mm , a = 13.8374(4), b = 14.5871(5), c = 21.9553(8) Å, α
3
mg, 13.8 μmol) in 0.5 mL of CH Cl was added to a CH Cl solution
2
2
2
2
= 86.185(1), β = 88.823(1), γ = 77.638(2)°, V = 4319.2(2) Å , ρ
=
calc
−3
−1
(
0.5 mL) of trans-chalcone (2.9 mg, 13.8 μmol) at room temperature,
1
.304 gcm , μ = 0.233 mm , empirical absorption correction (0.954
T ≤ 0.995), Z = 2, triclinic, space group P1 (No. 2), λ = 0.71073 Å,
T = 223(2) K, ω and φ scans, 36922 reflections collected (±h, ±k, ±l),
and then the reaction mixture was covered with cyclopentane (3 mL)
to eventually gave complex 25a as a yellow crystalline solid (14.8 mg,
≤
̅
−1
69% yield). Crystals suitable for X-ray single crystal analysis were
[
(sin θ)/λ] = 0.59 Å , 14614 independent (R = 0.057) and 11404
int
grown from a two layer procedure using CH Cl /cyclopentane at
2
2
observed reflections [I > 2σ(I)], 1093 refined parameters, R = 0.081,
2
−3
room temperature. Elemental Analysis: calcd. for C H BF OPZr ·
80
60
20
wR = 0.192, max. (min.) residual electron density 0.94 (−0.49) e.Å ,
CH Cl : C, 59.49; H, 3.82. Found: C, 59.33; H, 3.78. IR (KBr): 1644
2
2
hydrogen atoms calculated and refined as riding atoms.
−1 1
(
s), 1622 (m), 1512 (s), 1465 (s), 979 (s) cm . H NMR (600 MHz,
Preparation of Complex 27. Following the procedure described
for the preparation of 25a: reaction of complex 10 (22.1 mg, 15.6
μmol) with 1-phenylbut-2-yn-1-one (2.3 mg, 15.6 μmol) gave 27 as a
red crystalline solid (12.8 mg, 55% yield). Crystals suitable for X-ray
single crystal analysis were grown from a two layer procedure using
CH Cl /cyclopentane at room temperature. Elemental Analysis: calcd.
CD Cl , 299 K): δ = 8.40 (2H, o), 7.92 (1H, p), 7.89 (2H, m) (each
2
2
O
m, Ph P), 7.30 (3H, m,p), 7.21 (2H, o) (each m, Ph ), 6.96 (3H, m,p),
.91 (2H, o) (each m, Ph ), 6.94 (2H, m), 6.69 (1H, p), n.o. (very br,
H, o) (each br m, Ph P′) , n.o. (very br, 4H, o,m), 6.81 (br m, 1H, p)
Ph) , 5.26 (dd, J = 19.6 Hz, J = 6.2 Hz, 1H, CHPh), 4.56 (dd,
2
CH
6
2
t
2
t
2
3
(
PH HH
2
2
3
3
JPH = 6.1 Hz, J = 5.2 Hz, 1H, HC), 2.29 (s, 15H, C Me ), 1.83
HH
5
5
for C H BF OPZr · CH Cl : C, 58.10; H, 3.72. Found: C, 57.22; H,
75 56 20 2 2
1
t
−1
(
br, 3H, Me), 1.68 (s, 15H, C Me ′), [ tentative assignment].
4.09. IR (KBr): 1643 (m), 1513 (s), 1464 (s), 980 (s) cm . H NMR
5
5
1
3
1
2
O
C{ H} NMR (151 MHz, CD Cl , 299 K): δ = 171.4 (d, J = 8.0
(600 MHz, CD Cl , 299 K): δ = 7.70 (m, 2H, o-Ph ), 7.68 (m, 1H, p-
2
2
PC
2
2
3
1
O
O
Hz, C), 160.6 (d, J = 7.5 Hz, OC), 155.7 (d, J = 37.2 Hz,
Ph ), 7.61 (m, 2H, p-Ph P), 7.53 (m, 2H, m-Ph ), 7.46 (m, 4H, m-
PC
PC
2
3
t

CZr), 144.4 (d, J = 17.2 Hz, i), 127.3 (p), n.o. (o,m) (Ph) , 140.0
Ph P), 7.34 (m, 4H, o-Ph P), 7.02 (m, 1H, p-Ph), 6.87 (m, 2H, m-Ph),
PC
2
2
6
474
dx.doi.org/10.1021/ja3110076 | J. Am. Chem. Soc. 2013, 135, 6465−6476

Journal of the American Chemical Society
Article
3
6
.71 (m, 2H, o-Ph), 2.07 (s, 3H, Me), 1.97 (d, J = 11.3 Hz, 3H,
P.; Kehr, G.; Bergander, K.; Wibbeling, B.; Fro
̈
hlich, R.; Erker, G.
PH
13
1
MeC), 1.89 (s, 30H, C Me ). C{ H} NMR (151 MHz, CD Cl ,
Dalton Trans. 2009, 1534−1541. (c) Chen, D.; Wang, Y.;
5
5
2
2
2
3
2
99 K): δ = 199.8 (d, J = 49.3 Hz, C), 197.4 (d, J = 28.9
Klankermayer, J. Angew. Chem., Int. Ed. 2010, 49, 9475−9478.
PC
PC
2
1
Hz, OC), 173.2 (d, J = 1.7 Hz, C), 158.9 (d, J = 21.8 Hz,
́
(6) (a) Menard, G.; Stephan, D. W. J. Am. Chem. Soc. 2010, 132,
PC PC
1
3
ZrC), 148.5 (dm, J ∼ 245 Hz, C F ), 145.0 (d, J = 18.4 Hz, i-
1796−1797. (b) Zhang, Y.; Miyake, G. M.; Chen, E. Y. X. Angew.
Chem., Int. Ed. 2010, 49, 10158−10162. (c) Appelt, C.; Westenberg,
H.; Bertini, F.; Ehlers, A. W.; Slootweg, J. C.; Lammertsma, K.; Uhl,
FC
6
5
PC
1
1
Ph), 144.0 (d, J = 100.4 Hz, MeC), 138.7 (dm, J ∼ 250 Hz,
PC
FC
1
O
2
C F ), 136.6 (dm, J ∼ 250 Hz, C F ), 135.3 (p-Ph ), 134.1 (d, J
6
5
FC
6
5
PC
4
O
4
=
8.9 Hz, o-Ph P), 133.6 (d, J = 1.4 Hz, i-Ph ), 133.3 (d, J = 3.0
W. Angew. Chem., Int. Ed. 2011, 50, 3925−3928. (d) Men
Stephan, D. W. Angew. Chem., Int. Ed. 2012, 51, 4409−4412.
(e) Menard, G.; Stephan, D. W. Angew. Chem., Int. Ed. 2012, 51,
́
ard, G.;
2
PC
PC
O
O
3
Hz, p-Ph P), 129.8 (m-Ph ), 129.7 (o-Ph ), 129.2 (d, J = 10.9 Hz,
m-Ph P), 128.5 (m-Ph), 127.5 (d, J = 1.8 Hz, o-Ph), 127.4 (p-Ph),
2
PC
4
2
PC
́
1
1
3
(
2
26.8 (d, J = 64.1 Hz, i-Ph P), 124.3 (br, i-C F ), 121.9 (C Me ),
PC 2 6 5 5 5
8272−8275.
3
2
8.8 (d, J = 36.1 Hz, CH ), 22.3 (d, J = 19.9 Hz, MeC), 12.9
PC
3
PC
(7) (a) Hounjet, L. J.; Caputo, C. B.; Stephan, D. W. Angew. Chem.,
3
1
1
C Me ). P{ H} NMR (243 MHz, CD Cl , 299 K): δ = 33.2 (ν
∼
5
5
2
2
1/2
̈ ̈
Int. Ed. 2012, 51, 4714−4717. (b) Fromel, S.; Frohlich, R.; Daniliuc,
1
9
Hz). F NMR (564 MHz, CD Cl , 299 K): δ = −133.2 (br, 2F, o-
2
2
C. G.; Kehr, G.; Erker, G. Eur. J. Inorg. Chem. 2012, 3774−3779.
(8) Miller, A. J. M.; Labinger, J. A.; Bercaw, J. E. J. Am. Chem. Soc.
2010, 132, 3301−3303.
3
C F ), −163.9 (t, J = 20.3 Hz, 1F, p-C F ), −167.7 (m, 2F, m-
6
5
FF
6 5
1
1
1
C F ). B{ H} NMR (192 MHz, CD Cl , 299 K): δ = −16.7 (ν
∼
6
5
2
2
1/2
2
0 Hz).
X-ray Crystal Structure Analysis of Complex 27. Formula
C H BF OPZr · CH Cl , M = 1571.12, yellow-orange crystal, 0.30
(
9) Neu, R. C.; Otten, E.; Lough, A.; Stephan, D. W. Chem. Sci. 2011,
, 170−176.
10) (a) Chapman, A. M.; Haddow, M. F.; Wass, D. F. J. Am. Chem.
2
75
56
20
2
2
(
3
×
0.17 × 0.07 mm , a = 13.0151(2), b = 14.7358(2), c = 19.3515(3) Å,
α = 72.626(1), β = 73.566(1), γ = 82.426(1)°, V = 3392.81(9) Å , ρ
1.538 gcm , μ = 0.366 mm , empirical absorption correction
0.898 ≤ T ≤ 0.974), Z = 2, triclinic, space group P1 (No. 2), λ =
.71073 Å, T = 223(2) K, ω and φ scans, 37649 reflections collected
±h, ±k, ±l), [(sin θ)/λ] = 0.67 Å , 16542 independent (R
.041) and 13818 observed reflections [I > 2σ(I)], 931 refined
parameters, R = 0.052, wR = 0.115, max. (min.) residual electron
density 0.54 (−0.53) e.Å , hydrogen atoms were calculated and
Soc. 2011, 133, 8826−8829. (b) Chapman, A. M.; Haddow, M. F.;
Wass, D. F. J. Am. Chem. Soc. 2011, 133, 18463−18478. (c) Chapman,
A. M.; Haddow, M. F.; Wass, D. F. Eur. J. Inorg. Chem. 2012, 1546−
3
calc
−3
−1
=
(
0
(
̅
1554. (d) Chapman, A. M.; Wass, D. F. Dalton Trans. 2012, 41, 9067−
9072.
−1
=
int
(
11) Xu, X.; Fro
Commun. 2012, 48, 6109−6111.
12) (a) Jordan, R. F. Adv. Organomet. Chem. 1991, 32, 325−387.
b) Chen, E. Y. X.; Marks, T. J. Chem. Rev. 2000, 100, 1391−1434.
13) (a) Lauher, J. W.; Hoffmann, R. J. Am. Chem. Soc. 1976, 98,
̈
hlich, R.; Daniliuc, C. G.; Kehr, G.; Erker, G. Chem.
0
2
(
−3
(
refined as riding atoms.
(
1
729−1742. (b) Zachmanoglou, C. E.; Docrat, A.; Bridgewater, B. M.;
ASSOCIATED CONTENT
■
Parkin, G.; Brandow, C. G.; Bercaw, J. E.; Jardine, C. N.; Lyall, M.;
*
S
Supporting Information
Green, J. C.; Keister, J. B. J. Am. Chem. Soc. 2002, 124, 9525−9546.
(14) See for a comparison: (a) Moebs-Sanchez, S.; Bouhadir, G.;
Experimental details and physical characterization of the new
compounds, crystallographic data, and CIF files. This material
is available free of charge via the Internet at http://pubs.acs.org.
Saffon, N.; Maron, L.; Bourissou, D. Chem. Commun. 2008, 3435−
437. (b) Momming, C. M.; Kehr, G.; Wibbeling, B.; Frohlich, R.;
Erker, G. Dalton Trans. 2010, 39, 7556−7564. (c) Rosorius, C.; Kehr,
G.; Frohlich, R.; Grimme, S.; Erker, G. Organometallics 2011, 30,
4211−4219.
(15) (a) Mo
Grimme, S.; Stephan, D. W.; Erker, G. Angew. Chem., Int. Ed. 2009, 48,
643−6646. (b) Dureen, M. A.; Stephan, D. W. J. Am. Chem. Soc.
2010, 132, 13559−13568. (c) Peuser, I.; Neu, R. C.; Zhao, X.; Ulrich,
M.; Schirmer, B.; Tannert, J. A.; Kehr, G.; Frohlich, R.; Grimme, S.;
Erker, G.; Stephan, D. W. Chem.Eur. J. 2011, 17, 9640−9650.
(d) Harhausen, M.; Frohlich, R.; Kehr, G.; Erker, G. Organometallics
3
̈
̈
̈
AUTHOR INFORMATION
■
Corresponding Author
̈ ̈
mming, C. M.; Otten, E.; Kehr, G.; Frohlich, R.;
*E-mail: erker@uni-muenster.de.
6
Author Contributions
§
C.G.D. performed the X-ray crystal structure analysis.
̈
Notes
The authors declare no competing financial interest.
̈
2
012, 31, 2801−2809.
ACKNOWLEDGMENTS
(16) Bebbington, M. W. P.; Bontemps, S.; Bouhadir, G.; Bourissou,
■
D. Angew. Chem., Int. Ed. 2007, 46, 3333−3336.
Financial support from the Alexander von Humboldt Stiftung
(17) For another type of FLP azide coordination, see: Stute, A.; Kehr,
(stipend to X.X.) is gratefully acknowledged.
G.; Fro
̈
hlich, R.; Erker, G. Chem. Commun. 2011, 47, 4288−4290.
(18) (a) Welch, G. C.; Juan, R. R. S.; Masuda, J. D.; Stephan, D. W.
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(
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(
̈
hlich, R.; Schirmer, B.;
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NOTE ADDED AFTER ASAP PUBLICATION
In the version published ASAP April 17, 2013, Figures 1 and 3
were transposed, this was corrected and reposted April 19,
■
2
013.
6
476
dx.doi.org/10.1021/ja3110076 | J. Am. Chem. Soc. 2013, 135, 6465−6476