Reactions of Zn bis-ferrocenyl-β-diketiminates with [Ph 3C][B(C6F5)4]

Article abstract of DOI:10.1039/c1dt10452g

The ZnMe complexes of bis-ferrocenyl-β-diketiminate ligands are prepared and the reactions with [Ph₃C][B(C₆F ₅)₄] are found to yield the salts [H(Ph ₃C)C(MeC(N(C₅H₄)FeCp)₂ZnMe] [B(C₆F₅)₄] and [CH₂C(MeC(N(C ₅H₄)FeCp)₂ZnMe][B(C₆F ₅)₄], derived from electrophilic substitution and hydride abstraction.

Full text of DOI:10.1039/c1dt10452g

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COMMUNICATION
Reactions of Zn bis-ferrocenyl-b-diketiminates with [Ph C][B(C F ) ]†
3
6 5 4
Louisa J. E. Stanlake and Douglas W. Stephan*
Received 17th March 2011, Accepted 6th April 2011
DOI: 10.1039/c1dt10452g
The ZnMe complexes of bis-ferrocenyl-b-diketiminate
lation. In a similar fashion, MeC(NH(C
5
4
H )FeCp)CMeC(O)Me
ligands are prepared and the reactions with [Ph
3
C][B-
C)C-
[CH
from
2, was prepared in 63% yield. Compound 1 was heated at
130 C for 4 days with additional aminoferrocene in the pres-
◦
(
(
C
6
F
5
)
4
]
are found to yield the salts [H(Ph
3
˚
MeC(N(C
5
H
4
)FeCp)
2
ZnMe]
[B(C
6
F
5
)
4
]
and
2
ence of 3 A molecular sieves. Following work-up an orange
1
solid 3 was isolated in 56% yield. The H NMR spectrum
C(MeC(N(C
5
H
4
)FeCp)
2
ZnMe][B(C
6
F
5
)
4
],
derived
showed a signal at 12.7 ppm attributable to an N–H fragment
while signals at 4.68, 4.23, 4.20 and 3.91 ppm arise from CH,
electrophilic substitution and hydride abstraction.
1
–3
Cp and C
as MeC(NH(C
fashion, reactions of 2 with additional aminoferrocene afforded
MeC(NH(C )FeCp)CMeC(N(C )FeCp)Me 4 in 59% yield.
The H and C NMR resonances observed as well as mass spectral
data were consistent with this formulation. While this stepwise
procedure affords the bis-ferrocenyldiketiminate precursors 3 and
5
H
4
fragments consistent with the formulation of 3
The chemistry of b-diketiminate ligand complexes has under
gone a renaissance in the past decade. Part of the renewed interest
has arisen as a result of the facile synthesis and the ease with
which the ligand can be varied so as to tune the electronic
and steric features. Numerous studies have described the use of
these ligands targeting the development of reactive transition
metal systems. Indeed, there are a number of systems that have
been reported where these ligands act in an ancillary manner to
stabilize unusually reactive metal fragments or provide species
5
H
4
)FeCp)CHC(N(C )FeCp)Me. In a similar
5
H
4
5
13
H
4
5
H
4
1
4
, efforts to prepare these ligands directly via prolonged heating
◦
at 130 C for 4 days of two equivalents of aminoferrocene with
the corresponding acetylacetone resulted in the formation of a
complex and inseparable mixture of products. Similarly, efforts to
use conventional approaches such as acid catalysis or a Dean Stark
apparatus to prepare these b-diketiminates were also unsuccessful.
Nonetheless, the reasons for the success of the stepwise process
remain unclear.
4
–8
capable of catalyzing various processes. On the other hand there
are a number of reports in which the b-diketiminate ligands are
not innocent observers of the chemistry at the metal, but rather
9–12
undergo reactions on the ligand backbone.
An interesting possibility for a substituent on a b-bis-ketiminate
ligand is ferrocenyl as this is a robust, bulky yet electrochemically
active fragment. However, in contrast to alkyl or aryl derivatives
of b-diketiminates, generation of a species with ferrocenyl sub-
stituents is synthetically challenging. Indeed efforts to that end
have yielded only ferrocenylimine-b-ketone derivatives. In this
communication we report the synthesis of such b-diketiminate
ligands that have not been reported. These species are subse-
quently used to prepare Zn complexes. In contrast to Zn b-
diketiminate complexes that incorporate aryl substituents on N,
the reactivity of these bis-ferrocenyl-b-ketiminate Zn species with
) ] reveals unusual reactivity at the b-diketiminate
ligands. This non-innocent behaviour of the ligand arises from
hydride abstraction and electrophilic substitution.
Zn complexes of these ligands were readily prepared. Reaction
of the 3 with ZnMe proceeds with the evolution of methane and
2
results in the formation of a red solid 5 isolated in 89% yield. The
1
13
H NMR spectrum of 5 shows resonances attributable to the b-
diketeniminate ligand as well as a resonance at -0.18 ppm resulting
from the presence of the Zn–Me fragment. The corresponding
1
3
1
C{ H} NMR signal was observed at -7.8 ppm. These data
14
together with mass spectral and analytical data were consistent
with the formulation of 5 as HC(MeC(N(C
5
H
4
)FeCp) ZnMe. In a
2
similar fashion, stoichiometric reaction of 3 with Zn(N(SiMe
3
)
)
2 2
[
Ph
3
C][B(C
6
F
5
4
proceeds with release of amine and formation of the red solid 6.
Similar to 5, the NMR data for 6 was consistent with the presence
of the anionic ligand in a 1 : 1 ratio with a N(SiMe
3
2
) fragment. The
Aminoferrocene was combined with 2,4-pentanedione in
the presence of 3 A molecular sieves and reacted overnight.
Following work-up, dark orange needles of MeC(NH-
)FeCp)CHC(O)Me 1 were isolated in 89% yield. H,
NMR and mass spectral data were consistent with this formu-
silyl-methyl groups give rise to resonances at 0.33 and 5.3 ppm in
˚
1
13
the H and C NMR spectrum, respectively. Thus, the formulation
of 6 is (HC(MeC(N(C )FeCp) ZnN(SiMe . In an analogous
manner, the ligand 4 was reacted with ZnMe to give the analogous
b-diketeniminate complex MeC(MeC(N(C )FeCp) ZnMe 7.
1
13
5
H
4
2
)
3 2
(
C
5
H
4
C
2
5
H
4
2
This orange solid was isolated in 84% yield and showed NMR
resonances analogous to 5 with the additional signal arising from
the methyl group on the central carbon of the b-diketiminate
ligand.
Department of Chemistry, 80 St. George St., University of Toronto, Toronto,
Ontario, Canada, M5S 3H6. E-mail: dstephan@chem.utoronto.ca
†
CCDC reference number 818402. For crystallographic data in CIF or
other electronic format see DOI: 10.1039/c1dt10452g
5
836 | Dalton Trans., 2011, 40, 5836–5840
This journal is © The Royal Society of Chemistry 2011

View Article Online
Reaction of
5
with [Ph
3
C][B(C
6
F
5
)
4
]
proceeds in
dichloromethane or bromobenzene, resulting in an immediate
color change to dark purple. The product 8 was subsequently
isolated as purple needle-like crystals in 90% yield. The
1
observation of arene resonances in the H NMR spectrum of
8
were consistent with the inclusion of the trityl fragment. In
addition, the signals at 5.40, 4.10, 3.99 and 2.12 ppm were
consistent with the presence of the intact diketiminate ligand.
1
It is noteworthy that the H signal arising from the CH signal
in 8 is observed at 5.67 ppm, which is shifted dramatically from
4
.65 ppm in 5. As well, a signal at -0.72 ppm was attributed to
13 1
the retained ZnMe unit. Similarly, the corresponding C{ H}
resonances were observed with the Zn-methyl fragment giving rise
1
9
11
to a signal at -8.9 ppm. F and B NMR data were consistent
with the presence of the anion [B(C ] in 8. These data infer
the stoichiometric combination of 5 and [Ph C][B(C ]. The
6
F
)
5 4
3
6
F
)
5 4
precise nature of 8 was unambiguously determined by X-ray
crystallography‡ (Fig. 1). These data revealed the formation of a
new C–C bond between the trityl fragment and the central carbon
of the b-diketiminate ligand. This confirms the formulation of 8
as [H(Ph
3
C)C(MeC(N(C
5
H
4
)FeCp)
2
ZnMe][B(C
6
F ) ]. The cation
5
4
thus contains a three coordinate Zn center with Zn–N distances
˚
˚
of 2.0544(13) A and 2.0654(12) A, a Zn–C distance of 1.9567(16)
˚
◦
◦
A and N–Zn–N and C–Zn–N angles of 92.72(5) , 128.37(7)
◦
and 133.90(6) , respectively. The chelate ring on Zn adopts a
puckered pseudo-boat configuration, with the trityl fragment in
the axial position to accommodate the saturated central carbon.
This distortion of the ligand backbone minimizes the interactions
Scheme 1 Synthesis of 1–9.
by NMR spectroscopy confirmed the formation of Ph CH as
between the (C
5
H
4
)FeCp moieties and the Me substituents on the
3
1
Zn and the ligand backbone. This orientation presents one of the
arene rings in close proximity to the Zn with Zn–C distance of
a by-product. The species 9 gives rise to new H NMR res-
onances at 5.82 ppm attributable to olefinic protons resulting
from hydride removal from the central methyl fragment of 7.
˚
2
.577 A (Zn–C36), suggesting a weak donation from the arene
1
3
to the metal center. The ferrocenyl fragments on N are oriented
in a pseudo-transoid disposition, presumably to minimize steric
interactions with the trityl fragment.
The corresponding C resonances were observed at 171.5 ppm.
Resonances corresponding to the remainder of the b-diketiminate
1
ligand were observed in addition to the H singlet at 0.05 ppm
1
3
and C resonance at -9.4 ppm resulting from the Zn-bound
methyl group. These data are consistent the formulation of 9 as
[CH
2
C(MeC(N(C
5
H
4
)FeCp)
2
ZnMe] [B(C
6
F
5
)
4
].
While a trityl cation often reacts with metal alkyl species
resulting in alkyl-abstraction and generation of a coordinatively
unsaturated metal center, the formation of 8 and 9 is consistent
with the non-innocent behaviour of b-diketiminate ligands. More-
over, these observations suggest the possibility that the ferrocenyl
substituents sterically block reactivity of the Zn-methyl fragment
prompting reaction at the ligand backbone.
To further probe this aspect, DFT calculation were performed
on 7. The energy minimized structure showed a distortion in the
ligand backbone providing C
2
symmetry with C N–Zn–N
C
◦
dihedral angle of 10.4 (Fig.2) and a transoid disposition of the
ferrocenyl fragments. The computed distortion of the transoid
conformation presumably results from the minimization of the
interactions between the ferrocenyl moieties with the methyl
substituents on the Zn and the b-diketiminate ligand. Interest-
ingly, efforts to locate a minimum energy conformation of the
corresponding conformation of 7 in which the ferrocenyl groups
adopt a cisoid disposition were unsuccessful. In contrast similar
Fig. 1 POV-Ray rendering of ORTEP depictions of the cation of 8.
In a similar fashion the species 7 reacted with [Ph
3
C][B(C
6
F
5
)
4
]
calculations for the Zn complex HC(MeC(N(C
6
H
4
iPr ) ZnMe
2
2
to give a dark purple solution from which purple crystals of 9
revealed a minimum energy conformation in which the ligand-
were isolated in 85% yield. In this case, monitoring the reaction
Zn geometry is completely planar. Nonetheless, both 7 and
This journal is © The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 5836–5840 | 5837

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+
2
9.2 (C(O)CMe), 19.0 (MeC(NH)). MS(EI): 283 [M ]. Anal. calcd
for C15
H
17FeNO: C 63.63, H 6.05, N 4.95. Found: C 63.27, H 5.92,
N 4.80.
1
2: 0.278 g (63% yield) of dark orange needles. H NMR
(
2
2
C
H,
6
D
6
3
): 13.5 (s, 1H, N–H), 4.13 (s, 5H, Cp), 4.01 (broad t,
3
J
H–H = 2.0 Hz, H2,5-C
5
H
4
), 3.76 (broad t, 2H,
J
H–H
=
.0 Hz, H3,4-C
5
H
4
), 2.13 (s, 3H, MeCC(Me)CMe), 1.64 (s, 3H,
1
3
1
MeC(NH)), 1.59 (s, 3H, C(O)CMe). C{ H} (C
O), 159.6 (MeC(N(C )FeCp)), 100.0 (MeCC(Me)CMe),
5.5 (C -C ), 70.0 (C -Fe), 66.6 (C2,5-C ), 65.9 (C3,4-C ),
8.6 (C(O)CMe), 15.9 (MeC(NH)), 11.7 (MeCC(Me)CMe). Anal.
19FeNO: C 64.67, H 6.44, N 4.71. Found: C 62.50,
6
D
6
): 195.9
(
9
2
C
5
H
4
1
5
H
4
5
H
5
5
H
4
5
H
4
calcd for C16
H
H 6.10, N 4.74.
Synthesis of HC(MeC(N(C
5
H
4
)FeCp) (3)
2
In a Teflon-sealed flask, 1 (0.363 g, 1.28 mmol), aminoferrocene
˚
Fig. 2 (a) Space filling view of the DFT calculated energy minimized
structure of 7, the view is from the ligand side of the coordination plane.
(0.257 g, 1.28 mmol), approximately 0.25 g of 3 A molecular sieves
and a mechanical stirring bar were combined in 10 mL of toluene.
The flask was sealed and the reaction mixture was stirred and
heated at 130 C for 4 d. The flask was brought into an inert
(
b) Depiction of the HOMO of 7. (c) and (d) Analogous drawings for
◦
HC(MeC(N(C iPr ZnMe.
6
H
4
2 2
)
atmosphere glovebox, where the reaction was filtered through a
plug of Celite (to remove sieves) and dried in vacuo to give an
orange solid. The residual material was washed 3 ¥ 5 mL dry
HC(MeC(N(C
6
H
4
iPr ) ZnMe exhibit highest occupied molecular
2
2
orbitals (HOMO) that have significant components residing on
the central carbon of the b-diketiminate ligand. This presumably
accounts for the electrophilic attack by the trityl cation. The
transoid disposition of the ferrocenyl ligand in 7 occupies space
above and below the plane of the diketiminate ligand in a
dissymmetric fashion so as to provide access of the trityl cation
to the HOMO. In contrast, the symmetric conformation of
1
hexanes to give a clean orange solid (0.337 g, 56% yield). H NMR
(C D ): 12.7 (s, 1H, N–H), 4.68 (s, 1H, MeCC(H)CMe), 4.23 (s,
6
6
3
10H, Cp), 4.20 (t, 4H, J
H–H
= 2.0 Hz, H -C H ), 3.91 (t, 4H,
2,5
5
4
3
13 1
JH–H = 2.0 Hz, H -C H ), 1.84 (s, 6H, MeCC(H)CMe). C{ H}
3,4
5
4
(C D ): 160.5 (MeCC(H)CMe), 102.2 (MeCC(H)CMe), 98.3 (C -
6
6
1
C H ), 69.9 (C H -Fe), 65.0 (C -C H ), 64.8 (C -C H ), 21.1
5
4
5
5
2,5
5
4
3,4
5
4
+
HC(MeC(N(C
6
H
4
iPr
2
)
2
ZnMe blocks entry to the central position
(MeCC(H)CMe). MS(EI): 466 [M ]. Anal. calcd for C H Fe N :
2
5
26
2
2
on the ligand backbone. A number of reports have shown the non-
C 64.41, H 5.62, N 6.01. Found: C 63.94, H 5.76, N 6.08.
9–12
innocence of the ligand in b-diketiminate complexes.
Indeed,
hydride removal from the methyl groups on the carbons alpha
to the imine is well documented. Thus, the formation of 9 is
perhaps less surprising. However the formation of 8 provides a rare
example in which alkylation occurs with a sterically demanding
electrophile.
Synthesis of MeC(MeC(N(C
5
H
4
)FeCp) (4)
2
Synthesized in the same manner as compound 4, using 2
(0.333 g, 1.12 mmol), aminoferrocene (0.225 g, 1.12 mmol),
and approximately 0.25 g of 3 A˚ molecular sieves. The residual
material was washed with 3 ¥ 5 mL dry hexanes to give a
1
clean orange solid (0.317 g, 59% yield). H NMR (C
6
D ): 13.8
6
Experimental
3
(
H
s, 1H, N–H), 4.26 (s, 10H, Cp), 4.20 (t, 4H, JH–H = 2.0 Hz,
3
2,5-C
5
H
4
), 3.94 (t, 4H, JH–H = 2.0 Hz, H3,4-C
5
4
H ), 1.91 (s,
Synthesis of MeC(N(C
5
4
H )FeCp)CHC(O)Me (1) and
1
3
1
6
H, MeCC(Me)CMe), 1.72 (s, 3H, MeCC(Me)CMe). C{ H}
MeC(N(C )FeCp)CMeC(O)Me (2)
5
H
4
(
C
6
D
6
): 160.3 (MeCC(Me)CMe), 102.8 (MeCC(Me)CMe), 99.6
), 69.8 (C -Fe), 65.3 (C2,5-C ), 64.6 (C3,4-C ), 18.3
These compounds were prepared in a similar fashion and thus only
one preparation is detailed. Aminoferrocene (0.232 g, 1.15 mmol),
(C
1
-C
5
H
4
5
H
5
5
H
4
5
H
4
+
(MeCC(Me)CMe), 15.8 (MeCC(Me)CMe). MS(EI): 480 [M ].
Anal. calcd for C26 : C 65.03, H 5.88, N 5.83. Found:
2
3
,4-pentanedione (0.115 g, 1.15 mmol) and approximately 0.25 g of
H
28Fe
2
N
2
˚
A molecular sieves were combined in 10 mL of dichloromethane
C 64.59, H 6.33, N 6.26. E-Chem: E1/2 (CH
mV, -226 mV
2
2
Cl ) = 768 mV, -13.5
(
or diethyl ether) and stirred overnight. The reaction was filtered
through a plug of Celite (to remove residue from molecular sieves)
and dried in vacuo to an orange solid. The solid was recrystallized
two times from pentane (cooling to -30 C each time) affording
Synthesis of HC(MeC(N(C
HC(MeC(N(C )FeCp) ZnN(SiMe
MeC(MeC(N(C )FeCp) ZnMe (7)
5
H
4
)FeCp)
2
ZnMe (5), of
(6) and
◦
(
5
H
4
2
3 2
)
0
.327 g (89% yield) of dark orange needles.
5
H
4
2
1
1:
H NMR (C
6
6
D ): 12.5 (s, 1H, N–H), 4.99 (s, 1H,
3
MeCC(H)CMe), 4.05 (s, 5H, Cp), 3.95 (broad t, 2H, JH–H = 2.0 Hz,
H
These compounds were prepared in a similar fashion and thus
only one preparation is detailed. In an inert atmosphere glovebox,
3
2,5-C
5
H
4
), 3.71 (broad t, 2H, JH–H = 2.0 Hz, H3,4-C
5
H
4
), 2.05 (s,
): 195.4
)FeCp)), 97.0 (MeCC(H)CMe), 94.9
-Fe), 65.98 (C2,5-C ), 65.93(C3,4-C ),
1
3
1
3
H, MeC(NH)), 1.54 (s, 3H, C(O)CMe). C{ H} (C
O), 161.4 (MeC(N(C
-C ), 70.0 (C
6
D
6
4 (60 mg, 0.128 mmol) was dissolved in 5 mL dry toluene
◦
(
(
C
C
5
H
4
and cooled to -30 C while stirring. ZnMe
2
solution (10% w/v
1
5
H
4
5
H
5
5
H
4
5
H
4
in hexanes, 0.12 mL, 0.126 mmol) was added dropwise. The
5
838 | Dalton Trans., 2011, 40, 5836–5840
This journal is © The Royal Society of Chemistry 2011

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reaction was stirred overnight, and a red solid was isolated
Synthesis of [CH
2
C(MeC(N(C
5
H
4
)FeCp)
2
ZnMe][B(C
6
F
5
)
4
] (9)
by drying in vacuo and washing 2 ¥ 5 mL with pentane
Synthesized in the same manner as for compound 8, using 7
(
61 mg, 89%).
1
(10 mg, 0.018 mmol) and [CPh ][B(C ] (17 mg, 0.018 mmol).
3
6
F
5
)
4
5: H NMR (C
6
D ): 4.60 (s, 1H, MeCC(H)CMe), 4.16 (t, 4H,
6
3
3
A dark purple solid was isolated by layering the reaction mixture
with hexanes and leaving for 18 h at room temperature, decanting
J
H–H = 2.0 Hz, H2,5-C
5
H
4
), 4.12 (s, 10H, Cp), 3.88 (t, 4H, JH–H
=
2
.0 Hz, H3,4-C
5
H
4
), 1.92 (s, 6H, MeCC(H)CMe), 0.16 (s, 3H, Zn–
1
1
the residual liquid and drying in vacuo (20 mg, 85% yield). H
Me). H NMR (CD
2
Cl
2
): 4.65 (s, 1H, MeCC(H)CMe), 4.24 (t,
), 4.17 (s, 10H, Cp), 4.08 (t, 4H,
), 2.06 (s, 6H, MeCC(H)CMe), -0.18
): 166.6 (MeCC(H)CMe), 108.1
), 70.2 (C -Fe), 65.2 (C2,5
), 24.3 (MeCC(H)CMe), -7.8 (Zn-Me).
Zn: C 57.23,
3
NMR (C
CHPh ), 4.28 (broad s, 4H, H2,5-C
), 4.06 (s, 10H, Cp), 2.16 (s, 6H, MeCC( CH
6
D
5
Br): 5.82 (s, 2H, MeCC( CH
), 4.18 (broad s, 4H, H3,4
)CMe), 0.05
2
)CMe), 5.44 (s, 1H,
4
H, JH–H = 2.0 Hz, H2,5-C
5
H
4
3
3
5
H
4
-
J
H–H = 2.0 Hz, H3,4-C
5
H
4
1
3
1
C
5
H
4
2
(
s, 3H, Zn–Me). C{ H} (C
6
D
6
1
3
(
s, 3H, ZnMe). H NMR (CD
CHPh ), 7.21 (m, p-CHPh
6.45 (s, 2H, MeCC( CH
2
Cl
2
): 7.29 (t, JH–H = 7 Hz, m-
(MeCC(H)CMe), 100.0 (C -C
1
5
H
4
5
H
5
-
3
3
3
), 7.13 (d, JH–H = 7 Hz, o-CHPh
3
),
), 4.58 (t,
), 4.52 (t, 4H, JH–H = 2 Hz, H3,4
C
5
H
4
), 65.0 (C3,4-C
5
H
4
+
2
)CMe), 5.56 (s, 1H, CHPh
3
MS(EI): 529 [M - Me]. Anal. calcd for C26
H
28Fe
2
N
2
3
3
4
H, JH–H = 2 Hz, H2,5-C
5
H
4
-
H 5.17, N 5.13. Found: C 56.34, H 5.28, N 5.06. E-Chem: E1/2
C
5
H
4
), 4.30 (s, 10H, Cp), 2.64 (s, 6H, MeCC( CH
2
)CMe), 0.06
(
CH
2
Cl ) = 829 mV, -42 mV, -163 mV.
2
1
3
1
1
(s, 3H, ZnMe). C{ H} (C
98.5 (C -C ), 69.8 (C
), 22.4 (MeCC( CH
6
D
6
): 171.5 (MeCC( CH )CMe),
2
6: (127 mg, 92%). H NMR (C
6
D ): 4.82 (s, 1H, MeCC(H)CMe),
H–H = 2.0 Hz, H2,5-C
6
3
1
5
H
4
5
H
5
-Fe), 68.6 (C2,5-C
)CMe), -9.4 (ZnMe). Anal. calcd for
Zn: C 49.49, H 2.36, N 2.26.
5
H
4
), 65.6 (C3,4-
4
.52 (t, 4H,
J
5
H
4
), 4.02 (s, 10H,
), 2.46 (s, 6H,
3
C
C
5
H
H
4
2
Cp), 3.97 (t, 4H,
MeCC(H)CMe), 0.33 (s, 18H, NSiMe
1
J
H–H = 2.0 Hz, H3,4-C
5
1
H
4
3
1
27
30Fe
2
N
2
Zn C51
H
29BF20Fe
2
N
2
3
). C{ H} (C
6
5
D Br):
Found: C 49.32, H 2.22, N 2.14.
67.0 (MeCC(H)CMe), 105.4 (MeCC(H)CMe), 101.3 (C -
1
C
(
for C31
5
H
4
), 69.6 (C
MeCC(H)CMe), 5.3 (NSiMe
Si
5
H
5
-Fe), 65.6 (C2,5-C
5
H
4
), 65.5 (C3,4-C
5
H ), 24.8
4
+
X-Ray data collection, reduction, solution and refinement
3
). MS(EI): 689 [M ]. Anal. calcd
H
43Fe
2
N
3
2
Zn: C 53.89, H 6.27, N 6.08. Found: C 53.18,
Single crystals were coated in Paratone-N oil in the glovebox,
mounted on a MiTegen Micromount and placed under an N
H 6.16, N 6.12.
: (68 mg, 84%). H NMR (C
), 4.14 (s, 10H, Cp), 3.89 (t, 4H,
2
1
3
3
7
6
D
6
): 4.16 (t, 4H,
J
J
H–H
H–H
=
=
stream. The data were collected on a Bruker Apex II diffractome-
ter. The data were collected at 150(±2) K. Data reduction was
performed using the SAINT software package and an absorption
correction applied using SADABS. The structures were solved
by direct methods using XS and refined by full-matrix least-
2
2
3
1
.0 Hz, H2,5-C
.0 Hz, H3,4-C
5
H
4
5
4
H ), 2.02 (s, 6H, MeCC(Me)CMe), 1.74 (s,
1
3
1
H, MeCC(Me)CMe), 0.17 (s, 3H, Zn–Me). C{ H} (C
6
6
D ):
66.6 (MeCC(Me)CMe), 109.0 (MeCC(Me)CMe), 101.2 (C
1
-
C
5
H
4
), 70.2 (C
5
H
5
-Fe), 65.1 (C2,5-C
5
H
4
), 65.0 (C3,4-C
5
H
4
3
),
).
2
squares on F using XL as implemented in the SHELXTL suite of
22.1 (MeCC(Me)CMe), 18.9 (MeCC(Me)CMe), -8.8 (Zn–CH
15
programs. All non-hydrogen atoms were refined anisotropically.
+
MS(EI): 480 [M - ZnMe]. Anal. calcd for C27
57.95, 5.40, 5.01. Found: 52.89,
N 4.84.
H
30Fe
2
N
2
Zn:
Carbon-bound hydrogen atoms were placed in calculated posi-
tions using an appropriate riding model and coupled isotropic
temperature factors.
C
H
N
C
H
5.10,
Computational studies
All calculated structures were minimized using the Gaussian 03
Synthesis of [H(Ph
8)
3
C)C(MeC(N(C
5
H
4
)FeCp)
2
ZnMe][B(C
6
F ) ]
5
4
16
program at the B3LYP/6-31g(d) level of theory. All minimized
structures were found to contain no imaginary frequencies, unless
otherwise noted.
(
A solution of [CPh
3
][B(C
6
F ) ] (20 mg, 0.022 mmol) in deuter-
5
4
ated or non-deuterated dichloromethane (or bromobenzene) was
added to compound 4 (12 mg, 0.022 mmol). The solution
immediately turned a dark purple colour. The product was isolated
by layering hexanes over the reaction mixture and leaving at
Acknowledgements
Financial support of NSERC of Canada is gratefully acknowl-
edged. DWS is grateful for the award of a Canada Research Chair
and a Killam Research Fellowship for 2009–2011.
room temperature for 18 h, upon which time purple needle-
1
like crystals formed (29 mg, 90% yield). H NMR (C
6
D
5
Br):
), 4.10
), 3.99 (s, 10H, Cp), 2.12 (s, 6H, MeCC(H)C),
7
.20–7.07 (m, 15H, CPh
3
), 5.40 (s, 2H, MeCC(H)CPh
3
(
-
m, 8H, C
5
H
4
1
Notes and references
0.72 (s, 3H, ZnMe). H NMR (CD
), 5.67 (s, 1H, MeC C(H)CPh
), 4.32 (m, 4H, H3,4-C ), 4.16 (s, 10H, Cp),
.48 (s, 6H, MeC C(H)CPh
CMe), -0.07 (s, 3H, ZnMe). C{ H}
Br): 177.3 (MeCC(H)CPh CMe), 149.8, 147.4 (C ), 140.5
o-CHPh ), 137.8, 135.3 (C ), 128.3 (p-CHPh ), 99.6 (C
), 70.1 (C -Fe), 68.4 (C2,5-C ), 66.2 (C3,4-C ), 65.4
MeCC(H)CPh CMe), 28.7 (MeCC(H)CPh CMe), -8.9 (ZnMe).
Anal. calcd for C69 Zn: C 53.68, H 2.81, N 1.81.
Found: C 53.89, H 2.70, N 1.84.
2
Cl
2
): 7.47 (m, m-CHPh
3
),
7
.20 (m, o,p-CHPh
3
3
CMe), 4.42
¯
‡
A
Crystallographic data: space group = triclinic, P1; Z = 2, a = 12.8817(6)
◦
◦
˚
, b = 15.2658(7) A˚ , c = 17.4986(8) A˚ , a = 75.639(2) , b = 68.973(2) , g =
(
2
m, 4H, H2,5-C
5
H
4
5
H
4
◦
1
3
1
68.653(2) , V = 2964.2(2) A˚ 3, m = 0.994, data = 21 171, variables = 901, R
3
(
>3s) = 0.0379, wR = 0.1062, GOF = 1.046.
2
(
(
C
6
D
5
3
6
F
5
3
6
F
5
3
1
-
1 C. Ruspic and S. Harder, Inorg. Chem., 2007, 46, 10426–10433.
2 L. Bourget-Merle, M. F. Lappert and J. R. Severn, Chem. Rev., 2002,
C
5
H
4
5
H
5
5
H
4
5
H
4
1
02, 3031–3066.
(
3
3
3
W. E. Piers and D. J. H. Emslie, Coord. Chem. Rev., 2002, 233–234,
H
43BF24Fe
2
N
2
1
31–155.
4 D. J. Mindiola, Angew. Chem., Int. Ed., 2009, 48, 6198–6200.
This journal is © The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 5836–5840 | 5839

View Article Online
5
6
B. L. Tran, M. Pink, X. Gao, H. Park and D. J. Mindiola, J. Am. Chem.
Soc., 2010, 132, 1458–1459.
15 G. M. Sheldrick, Bruker AXS Inc., Madison, WI,
2000.
J. Spielmann, M. Bolte and S. Harder, Chem. Commun., 2009, 6934–
16 M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb,
J. R. Cheeseman, J. J. A. Montgomery, T. Vreven, K. N. Kudin, J. C.
Burant, J. M. Millam, S. S. Iyengar, J. Tomasi, V. Barone, B. Mennucci,
M. Cossi, G. Scalmani, N. Rega, G. A. Petersson, H. Nakatsuji, M.
Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T.
Nakajima, Y. Honda, O. Kitao, H. Nakai, M. Klene, X. Li, J. E.
Knox, H. P. Hratchian, J. B. Cross, V. Bakken, C. Adamo, J. Jaramillo,
R. Gomperts, R. E. Stratmann, O. Yazyev, A. J. Austin, R. Cammi,
C. Pomelli, J. W. Ochterski, P. Y. Ayala, K. Morokuma, G. A. Voth,
P. Salvador, J. J. Dannenberg, V. G. Zakrzewski, S. Dapprich, A. D.
Daniels, M. C. Strain, O. Farkas, D. K. Malick, A. D. Rabuck, K.
Raghavachari, J. B. Foresman, J. V. Ortiz, Q. Cui, A. G. Baboul, S.
Clifford, J. Cioslowski, B. B. Stefanov, G. Liu, A. Liashenko, P. Piskorz,
I. Komaromi, R. L. Martin, D. J. Fox, T. Keith, M. A. Al-Laham, C.
Y. Peng, A. Nanayakkara, M. Challacombe, P. M. W. Gill, B. Johnson,
W. Chen, M. W. Wong, C. Gonzalez and J. A. Pople, Gaussian, Inc.,
Wallingford CT, 2004.
6
936.
7
8
9
P. L. Holland, Acc. Chem. Res., 2008, 41, 905–914.
C. J. Cramer and W. B. Tolman, Acc. Chem. Res., 2007, 40, 601–608.
K. Mochizuki, S. Manaka, I. Takeda and T. Kondo, Inorg. Chem.,
1
996, 35, 5132–5136.
0 C. E. Radzewich, M. P. Coles and R. F. Jordan, J. Am. Chem. Soc.,
998, 120, 9384–9385.
1
1
1
1
1 S. Yokota, Y. Tachi and S. Itoh, Inorg. Chem., 2002, 41, 1342–1344.
2 D. T. Carey, E. K. Cope-Eatough, E. Vilaplana-Mafe, F. S. Mair, R. G.
Pritchard, J. E. Warren and R. J. Woods, Dalton Trans., 2003, 1083–
1
093.
1
1
3 Y.-F. Yuan, T. Cardinaels, K. Lunstroot, K. Van Hecke, L. Van
Meervelt, C. G o¨ rller-Walrand, K. Binnemans and P. Nockemann,
Inorg. Chem., 2007, 46, 5302–5309.
4 J. Wu, T.-L. Yu, C.-T. Chen and C.-C. Lin, Coord. Chem. Rev., 2006,
2
50, 602–626.
5
840 | Dalton Trans., 2011, 40, 5836–5840
This journal is © The Royal Society of Chemistry 2011