Synthesis and properties of novel ortho-metalated cobalt(I) and iron(II) complexes through Csp2-H bond activation of dibenzylphenylphosphine

Article abstract of DOI:10.1016/j.jorganchem.2011.03.028

Dibenzylphenylphosphine in the reaction with CoMe(PMe₃) ₄ afforded complex [(Me₃P)₃Co((ortho-C ₆H₄)∩P(C₆H₅)(CH ₂C₆H₅))] (1) by C_sp2-H activation via ortho-metalation with P atom as anchoring group. An unexpected dinitrogen iron(II) complex [(Me₃P)₂(N₂)Fe((ortho-C ₆H₄)₂∩P(C₆H₅))] (2) stabilized by two five-membered chelate rings as [CPC]-pincer ligand was formed through the reaction of dibenzylphenylphosphine with FeMe₂(PMe ₃)₄ via double C_sp2-H activation. The reactions of complexes 1 and 2 with carbon monoxide delivered carbonyl complexes [(Me₃P)(CO)₂Co((ortho-C₆H₄) ∩P(C₆H₅)(CH₂C₆H₅))] (3) and [(Me₃P)₂(CO)Fe((ortho-C₆H ₄)₂∩P(C₆H₅))] (4). An iodo methyl cobalt(III) complex [(Me₃P)₂(Me)(I)Co((ortho-C ₆H₄)∩P(C₆H₅)(CH ₂C₆H₅))] (5) was isolated through the reaction of 1 with iodomethane. The structures of 1, 2, 3, 4 and 5 were determined by X-ray diffraction.

Full text of DOI:10.1016/j.jorganchem.2011.03.028

Journal of Organometallic Chemistry 696 (2011) 2537e2542
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Synthesis and properties of novel ortho-metalated cobalt(I) and iron(II)
complexes through Csp2eH bond activation of dibenzylphenylphosphine
*
Nazhen Liu, Xiaoyan Li, Hongjian Sun
School of Chemistry and Chemical Engineering, Shandong University, 250100 Jinan, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Dibenzylphenylphosphine in the reaction with CoMe(PMe3)4 afforded complex [(Me3P)3Co((ortho-
C6H4)XP(C6H5)(CH2C6H5))] (1) by Csp2eH activation via ortho-metalation with P atom as anchoring
group. An unexpected dinitrogen iron(II) complex [(Me3P)2(N2)Fe((ortho-C6H4)2XP(C6H5))] (2) stabilized
by two five-membered chelate rings as [CPC]-pincer ligand was formed through the reaction of diben-
zylphenylphosphine with FeMe2(PMe3)4 via double Csp2eH activation. The reactions of complexes 1 and
Received 28 January 2011
Received in revised form
24 March 2011
Accepted 25 March 2011
2
with carbon monoxide delivered carbonyl complexes [(Me3P)(CO)2Co((ortho-C6H4)X
Keywords:
P(C6H5)(CH2C6H5))] (3) and [(Me3P)2(CO)Fe((ortho-C6H4)2XP(C6H5))] (4). An iodo methyl cobalt(III)
complex [(Me3P)2(Me)(I)Co((ortho-C6H4)XP(C6H5)(CH2C6H5))] (5) was isolated through the reaction of 1
with iodomethane. The structures of 1, 2, 3, 4 and 5 were determined by X-ray diffraction.
Ó 2011 Elsevier B.V. All rights reserved.
CeH activation
ortho-Metalation
Cobalt
Iron
Dibenzylphenylphosphine
1. Introduction
2. Results
Carbonehydrogen bond activation is of great importance not
only in the research on fundamental theories but also in industrial
applications. Many of these studies have involved CeH bond acti-
vation mediated by transitionemetal complexes. In the past twenty
years some examples on Csp2eH bond activation through tran-
sitionemetal complexes were reported under mild conditions with
high selectivity [1e4]. Through CeH activation metal-hydrogen
bond is generated. This procedure plays an important role in
organometallic chemistry because metal hydrides are indispens-
able intermediates in many chemical transformations referring to
insertion with a wide variety of unsaturated compounds [5]. The
possibility of direct introduction of a new CeC bond via CeH bond
cleavage is a highly attractive strategy in synthetic chemistry [6].
Klein reported CeH activation of azobenzene [7] and phenyl
phosphites [8] using cobalt complexes supported by trimethyl-
phosphine via ortho-metalation.
2.1. Reaction of CoMe(PMe3)4 with dibenzylphenylphosphine
Reaction of CoMe(PMe3)4 with dibenzylphenylphosphine
delivered the ortho-metalated cobalt(I) complex 1 through CeH
bond activation via ortho-metalation with the escape of methane
(Eq. (1)).
CoMe(PMe )
+
3 4
PMe3
PMe3
P
P
Co
CH4,
PMe3
PMe3
1
(1)
As a complement to the research of CeH bond activation by the
elements of 8th group in the periodic table herein we report our
recent progress in the cyclometalation of dibenzylphenylphosphine
with cobalt and iron complexes supported by trimethylphosphine.
Crystallization at 0 ꢀC afforded red crystals of complex 1 in the
yield of 44%. In 1H NMR spectra PMe3 group resonances appear at
0.95 and 1.51 ppm. The singlet at 3.40 ppm is assigned to the “free”
PCH2 group, while another singlet at 4.12 ppm belongs to the PCH2
group within the chelate ring. The resonance for the two PCH2
groups in free dibenzylphenylphosphine ligand is registered at
3.10 ppm as a singlet [9]. In 31P NMR spectra a singlet with a reso-
nance at 9.2 ppm was found for two PMe3 ligands. The third PMe3
* Corresponding author. Tel.: þ86 531 88361350; fax: þ86 531 88564464.
E-mail address: hjsun@sdu.edu.cn (H. Sun).
0022-328X/$ e see front matter Ó 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2011.03.028

2538
N. Liu et al. / Journal of Organometallic Chemistry 696 (2011) 2537e2542
ligand shows a singlet at 22.7 ppm. The phosphor resonance of
PCH2 group appears at 70.1 ppm.
CoMe(PMe )
The molecular structure of complex 1 (Fig. 1) shows a trigonal
bipyramidal configuration around cobalt with C25 and P3 on axial
direction with the bond angle of C25eCo1eP3 172.73(5)ꢀ bending
toward the chelate ring. A five-membered metallacycle is formed
through the coordination of the P atom of dibenzylphenylphos-
phine and the ortho-chelated carbon atom. The bite angle
(C25eCo1eP4) of the chelate ligand is 79.87(5)ꢀ, which is signifi-
cantly larger than that (71.48(10)ꢀ in the similar Co(I) complex with
the four-membered chelate ring [8]. The five-membered chelate
ring (Co1P4C23C24C25) is nonplanar because the sum of the bond
angles is 524.57ꢀ.
+
3
4
PMe3
PMe3
P
P
Co
CH4,
PMe3
PMe3
1
CoMe(PMe )
+
CH4,
3
4
PMe3
PMe
+
3
A proposed reaction mechanism is described in Scheme 1. The
reaction likely begins with the coordination of dibenzylphenyl
phosphine-P atom by substituting one of the trimethylphosphine
ligand, which brings the metal closer to the ortho-(Csp2eH) bond of
the benzyl group. This chelation results in an easier and selective
H
Oxidative Addition
PMe3
PMe3
P
Co
Me
P
PMe3
PMe3
PMe3
PMe3
Co
Me
Csp2eH bond cleavage of benzyl group to give an active methyl
hydrido cobalt(III) intermediate, which affords cobalt(I) complex 1
Scheme 1. Proposed formation mechanism of complex 1.
with the escape of methane via reductive elimination.
In the IR spectra n ,
(N^N) absorption was found at 2078 cmꢁ1
2.2. Reaction of Fe(Me)2(PMe3)4 with dibenzylphenylphosphine
which is in the range of infrared stretching frequencies of dini-
trogen iron complex [10e14]. In 1H NMR spectra two PMe3 groups
resonate at 0.89 ppm as a singlet. Two sets of PCH2 were recorded at
2.91 and 3.47 ppm.
Under similar reaction conditions, instead of CoMe(PMe3)4,
Fe(Me)2(PMe3)4 was used in the reaction of dibenzylphenylphos-
phine (eq. (2)). A dinitrogen iron(II) complex 2 as yellow crystals
was isolated from diethyl ether in the yield of 26%. Complex 2 was
formed through double Csp2eH bond activation of two benzyl
groups under elimination of two methane molecules via double
ortho-metalation.
The molecular structure of complex 2 is shown in Fig. 2. The
configuration of complex 2 about the iron atom is close to octa-
hedral with a [CPC]-pincer ligand. C5 and P3 atoms are trans-
orientated in axial positions with the bond angle C5eFe1eP3
(177.76(11)ꢀ). Two five-membered metallacycles are formed
through the coordination of the P atom in the chelate ligand and
the two ortho-metalated C atoms. Both of the chelate rings are
almost perpendicular to each other. The sum of internal bond
angles (539.3ꢀ) of one chelate ring (Fe1P1C13C6C5) indicates ideal
planarity of the five atoms, while another metallacycle
(Fe1P1C14C15C16) with the sum of internal angles (527.53ꢀ) is
remarkably distorted. The bond length of terminal coordinate
dinitrogen (N1eN2 ¼ 1.113(4) Å) is close to that found in related
iron complexes [15]. This bond distance is a little bit longer than the
distance (1.0976 Å) in free N2. This implies that the triple bond is
weakly activated [10].
FeMe (PMe ) , N
2
+
2
3
4
P
P
Fe
2CH4, 2 PMe3
Me3P
PMe3
N2
2
(2)
The interaction of iron with nitrogen is of significant practical
and theoretical importance in many fields, such as catalysis,
biology and atmospheric chemistry [16]. In the Haber process the
dissociation of N2 over iron is critical in the formation of
ammonia. Many articles have been published in the field of
activation of dinitrogen by iron complexes [17,18]. We are making
our efforts to explore the chemical properties of dinitrogen iron
complex 2.
2.3. Reaction of complexes 1 and 2 with carbon monoxide
Stirring a solution of 1 in CO atmosphere (1 bar) gave rise to
complex 3 (eq. (3)). Complex 3 was formed through substitution of
two trimethylphosphine groups by two carbonyl ligands. An
expected insertion of CO into the CoeC bond as the case of the
cobalt complex in the literature [8] did not occur, because the
complex with five-membered chelate ring is more stable than that
with four-membered chelate ring. The tension of four-membered
ring is relieved by transferring to five-membered chelate ring via
carbonylation [8].
Fig. 1. Molecular structure of 1 and selected bond distances (Å) and angles (deg):
Co1eC25 2.0164(15), Co1eP1 2.2054(6), Co1eP2 2.1923(6), Co1eP3 2.1751(6), Co1eP4
2.1473(6); C25eCo1eP3 172.73(5), C25eCo1eP4 79.87(5), C25eCo1eP2 82.50(5).

N. Liu et al. / Journal of Organometallic Chemistry 696 (2011) 2537e2542
2539
vibration (2078 cmꢁ1) of N^N in complex 2 is replaced by the
corresponding vibration (1941 cmꢁ1) of C^O in complex 4. In the 1H
NMR spectra two PMe3 ligands appear as doublet at 0.78 ppm. The
PCH2 groups resonate at 3.35 and 3.44 ppm as doublets. In the
31P NMR spectra the PCH2 resonates at 82.8 ppm as triplets
(2JP,P ¼ 50.0 Hz). The PMe3 groups appear at 11.6 ppm as doublets
(2JP,P ¼ 50.0 Hz). IR and NMR data support the structure assigned for
complex 4.
CO
+
P
P
N2
Fe
Fe
Me3P
PMe3
Me3P
PMe3
N2
CO
2
4
(4)
Complex 4 crystallizes from diethyl ether at 0 ꢀC as yellow plates.
The molecular structure of complex 4 (Fig. 4) shows an octahedral
coordination geometry. FeeCO distance (Fe1eC23 ¼ 1.7332(18) Å) is
significantly
shorter
than
FeeCortho
bond
distances
Fig. 2. Molecular structure of 2 and selected bond distances (Å) and angles (deg):
Fe1eC5 2.024(4), Fe1eC16 2.053(4), Fe1eP1 2.1935(11), FeeP3 2.2739(13), FeeP4
2.2777(12), Fe1eN1 1.803(3), N1eN2 1.113(4); C5eFe1eP3 177.76(11), P4eFe1eC16
169.44(11), P1eFe1eN1 168.19(11), Fe1eN1eN2 179.1(4), C5eFe1eC16 84.55(15),
C13eP1eC14 104.17(18).
(Fe1eC1¼2.0554(17)andFe1eC7¼2.0246(17) Å)reflects thestrong
interaction between iron center and carbonyl ligands as an -donor/
-acceptor ligand. The bond distance C23eO1 (1.158(2) Å) is
s
p
comparable with those (C21eO11.148(3) and C22eO2 1.145(3) Å) in
complex 3 and much longer than the bond distance in free CO
molecule.
2.4. Reaction of complex 1 with iodomethane
CO
2
2
+
Cobalt(I) complex 1 generated in situ through the reaction of
CoMe(PMe3)4 and dibenzylphenylphosphine reacted with iodo
P
PMe3
CO
P
PMe3
PMe3
Co
CO
Co
PMe3
PMe3
1
3
(3)
Crystallization at 0 ꢀC afforded yellow crystals of complex 3. The
IR spectra contain two bands at 1898 and 1958 cmꢁ1 assigned to the
two terminal carbonyl ligands. In the 31P NMR spectra the signals
at 56.9 and 12.0 ppm belong to dibenzylphenylphosphine and tri-
methylphosphine ligand. In the 1H NMR spectra the trimethyl-
phosphine group appears as doublet at 1.10 ppm.
The molecular structure of complex 3 (Fig. 3) confirms the
trigonal bipyramidal coordination geometry in the crystal. The
bond angle C1eCoeP2 (178.11(8)ꢀ) in the axial direction deviates
from 180ꢀ. The sum of internal bond angles (535.4ꢀ) of this chelate
ring indicates little deviation from planarity of the five atoms
(CoC1C6C7P1). The chelate bite angle (C1eCoeP1 ¼ 83.20(9)ꢀ) is
comparable with that (83.97(12)ꢀ) in the related cobalt(I) complex
[19]. The CoeCO bond distances (CoeC21
¼
1.742(2) and
CoeC22 ¼ 1.750(3) Å) are in the region of those for carbonyl
cobalt(I) complexes [20], but both of them are remarkably shorter
than CoeC1 bond distance (2.014(3) Å) because of the enhance-
ment of
p-backbonding of the coordinate carbonyl ligands. As
expected, the carboneoxygen distances (C21eO1 1.148(3) and
C22eO2 1.145(3) Å) are longer than that (1.1282 Å) in free CO
molecule [21] due to the activation of carbonyl bond.
Under the same reaction conditions the reaction of 2 with CO
afforded complex 4. In this process complex 4 was formed through
a simple substitution of N2 by CO. In the IR spectra the stretching
Fig. 3. Molecular structure of 3 and selected bond distances (Å) and angles (deg):
C1eCo 2.014(3), CoeC21 1.742(2), CoeC22 1.750(3), CoeP1 2.1892(6), CoeP2
2.2044(8); C21eO1 1.148(3). C22eO2 1.145(3); C1eCoeP2 178.11(8), P1eCoeC21
117.29(8), C1eCoeC22 89.56(16), P2eCoeC22 92.14(14).

2540
N. Liu et al. / Journal of Organometallic Chemistry 696 (2011) 2537e2542
atom is situated in trans-position of the ortho-metalated C26 atom,
while the methyl ligand occupies the opposite location to the
chelate P atom. The sum of the internal bond angle of the five-
membered chelate ring (CoeP3C25C14C26) is 521.470 indicates
that the five atoms are not coplanar. The bond distance CoeP3
(2.2813(12) Å) is a little bit longer than the other two CoeP
distances (CoeP1 2.2564(14) and CoeP2 2.2574(13) Å). This is
caused by the strong trans-influence of the methyl ligand. The
length of (CoeI1 ¼ 2.7051(7) Å) is close to that in related
compound [22].
3. Conclusion
Dibenzylphenylphosphine in the reaction with CoMe(PMe3)4
afforded complex 1 by Csp2eH activation via ortho-metalationwith P
atom as anchoring group. An unexpected dinitrogen iron(II)
complex 2 stabilized by two five-membered chelate rings as [CPC]-
pincer ligand was formed through the reaction of dibenzylphenyl-
phosphine with FeMe2(PMe3)4. The reactions of complexes 1 and 2
with carbon monoxide delivered carbonyl complexes 3 and 4. The
iodo methyl cobalt(III) complex 5 was isolated through the reaction
of complex 1 with iodomethane. The structures of complexes 1, 2, 3,
4 and 5 were determined by single crystal X-ray diffraction.
Fig. 4. Molecular structure of 4 and selected bond distances (Å) and angles (deg):
Fe1eC1 2.0554(17), Fe1eC7 2.0246(17), Fe1eC23 1.7332(18), Fe1eP2 2.2292(4),
C23eO11.158(2), C23eFe1eP2 168.24(7), C1eFe1eP4 168.93(5), P3eFe1eC7 177.27(5),
Fe1eC23eO1 178.87(19).
4. Experimental section
4.1. General procedures and materials
methane to afford cobalt(III) complex 5 by undergoing an oxidative
addition reaction (eq. (5)).
All air-sensitive materials were handled either in vacuo or under
nitrogen by using standard Schlenk techniques. Dibenzylphenyl-
phosphine and CoMe(PMe3)4 and FeMe2(PMe3)4 were prepared
according to published procedures [23,24]. All solvents were dehy-
drated and degassed before use. Infrared spectra (4000e400 cmꢁ1),
as obtained from Nujol mulls between KBr disks, were recorded on
a Bruker alpha FT-IR. 1H, 13C, and 31P NMR (300, 75, and 121 MHz,
respectively) spectra were recorded on a Bruker Avance 300 spec-
trometer. 13C and 31P NMR resonances were obtained with broad-
band proton decoupling.
CoMe(PMe )
1)
2)
3
4
PMe3
I
P
P
[Me P]I CH
2
+
+
4
4
Co
(5)
3 MeI
Me
PMe3
5
Orange crystals of complex 5 are obtained from pentane at 0 ꢀC.
The molecular structure of 5 (Fig. 5) shows a slightly distorted
octahedral frame of donor atoms centered by a cobalt atom bearing
one I-, two C- and three P-atoms. Owing to trans-influence iodine
4.2. Synthesis of 1
The solution of CoMe(PMe3)4 (0.58 g, 1.54 mmol) in 20 ml of THF
was added dibenzylphenylphosphine (0.45 g,1.55 mmol) in 20 ml of
THF. After stirring at room temperature for 48 h, the color of the
solution turned to deep red. THF was evaporated in vacuo and the
residue was extracted bypentane. Crystallization at 0 ꢀC afforded the
deep red plates which are suitable for X-ray diffraction analysis.
Yield: 0.36 g of 1 (40.4%). Analysis for 1 C29H45CoP4, [found (calcu-
lated)]: C, 60.13 (60.42); H, 7.52 (7.88). 1H NMR (CDCl3, 673.2 K,
ppm): 0.95 (s,18H, PCH3), 1.51 (s, 9H, PCH3), 3.40 (s, 2H, PhCH2), 4.12
(s, 2H, PhCH2), 6.47e7.33 (m, 14H, AreH). 31P NMR (CDCl3, 673.2 K,
ppm): 70.1 (s, 1P, PhCH2P), 9.2 (s, 2P, PMe3), 22.7 (s, 1P, PMe3).
4.3. Synthesis of 2
The solution of FeMe2(PMe3)4 (0.65 g, 1.68 mmol) in 20 ml THF
was added dibenzylphenylphosphine (0.49 g, 1.70 mmol) in 20 ml
THF. After stirring at room temperature for 48 h, the color of the
solution turned brown. THF was evaporated in vacuo and the
residue was extracted by pentane and diethyl ether. Crystallization
at 0 ꢀC afforded the yellow plates which are suitable for X-ray
diffraction analysis. Yield: 0.23 g of 2 (26.0%). Analysis for 2
C26H35FeN2P3, [found (calculated)]: C, 59.26 (59.56); H, 6.42 (6.73);
Fig. 5. Molecular structure of 5 and selected bond distances (Å) and angles (deg):
CoeC30 2.048(5), CoeC26 1.989(5), CoeI1 2.7051(7), CoeP1 2.2564(14), CoeP2
2.2574(13); C26eCoeI1 174.19(13), P3eCoeC30 169.28(16), P2eCoeP1 163.96(6).
N 5.03 (5.34). m.p. 110e112 ꢀC (dec.). IR (Nujol):
cmꢁ1. 1H NMR (CDCl3, 292.4 K, ppm): 0.89 (s,18H, PCH3), 2.91 (s, 2H,
n
¼ 2078 (N^N)

N. Liu et al. / Journal of Organometallic Chemistry 696 (2011) 2537e2542
2541
Table 1
Crystallographic Data for Complexes 1e5.
1
2
3
4
5
Empirical formula
fw
Cryst syst
Space group
a, Å
C29H45CoP4
C26H35FeN2P3
524.34
monoclinic
P2(1)/n
9.2974(17)
19.069(3)
14.792(3)
90
90.377(3)
90
2622.5(8)
4
C25H27CoO2P2
480.37
C27H35FeOP3
526.43
monoclinic
P2(1)/n
9.2884(5)
19.0589(11)
14.7526(9)
90
90.8110(10)
90
2611.3(3)
4
C27H39CoIP3
642.18
triclinic
P-1
11.0447(13)
11.2627(14)
14.1430(17)
78.835(2)
80.412(2)
69.715(2)
1609.5(3)
2
576.46
monoclinic
P2(1)/c
9.788(2)
13.260(3)
23.416(5)
90
93.26(3)
90
3034.2(11)
4
monoclinic
P2(1)/n
12.9608(9)
14.5619(10)
13.7839(10)
90
108.1630(10)
90
2471.9(3)
4
b, Å
c, Å
a
, deg
, deg
b
g
, deg
V, Å3
Z
Dc, g cmꢁ3
1.262
1.328
1.291
1.309
1.325
No. of rflns collected
No. of unique data
Rint
13762
6062
0.0220
26.73
10423
3463
0.0476
22.64
14291
5565
0.0206
27.53
15096
5845
0.0166
27.50
9433
6934
0.0149
27.54
qmax, deg
R1 (I > 2
wR2 (all data)
s
(I))
0.0290
0.0784
0.0400
0.0986
0.0382
0.1097
0.0317
0.0902
0.0512
0.1981
PhCH2), 3.47 (s, 2H, PhCH2), 6.41e8.02 (m, 14H, AreH). 31P NMR
(CDCl3, 292.4 K, ppm): 71.3 (s, 1P, PhCH2P), 4.5 (s, 1P, PMe3), 8.2 (d,
2JP,P ¼ 86.8 Hz, 1P, PMe3).
4.6. Synthesis of 5
The solution of CoMe(PMe3)4 (0.46 g, 1.22 mmol) in 20 ml of THF
was added dibenzylphenylphosphine (0.35 g, 1.21 mmol) in 20 ml
of THF. After stirring at room temperature for 48 h, CH3I (0.2 g,
1.41 mmol) was added. The solution turned orange. THF was
evaporated in vacuo and the residue was extracted by pentane.
Crystallization at 0 ꢀC afforded complex 5 as orange crystals suit-
able for X-ray diffraction analysis. Yield: 0.10 g of 5 (32%). Analysis
for 5 C27H39CoIP3, [found (calculated)]: C, 50.13 (50.50); H, 6.32
(6.12). m.p. 101e103 ꢀC (dec.). 1H NMR (CDCl3, 294.8 K, ppm): 0.48
(d, 3JP,H ¼ 6.3 Hz, 3H, CoCH3), 1.25 (d, 2JP,H ¼ 3.9 Hz, 18H, PCH3), 2.13
(s, 4H, PCH2), 6.51e7.42 (m, 14H, CH). 31P NMR (CDCl3, 294.8 K,
ppm): 12.5 (s, 2P, PMe3), ꢁ4.9 (s, P, PCH2).
4.4. Synthesis of 3
The solution of complex 1 (0.21 g, 0.36 mmol) in 20 ml diethyl
ether was stirred under 1 bar CO for 12 h. The color of the solution
turned light yellow. Diethyl ether was evaporated in vacuo and the
residue was extracted by pentane. Crystallization at 0 ꢀC afforded
complex 3 as yellow cubic crystals suitable for X-ray diffraction
analysis. Yield:0.067 gof3 (40%). Analysisfor3 C25H27CoO2P2, [found
(calculated)]: C, 62.53 (62.51); H, 5.32 (5.67). m.p. 92e94 ꢀC (dec.). IR
(Nujol):
n
¼ 1898, 1958 (C]O) cmꢁ1. 1H NMR (CDCl3, 295.5 K, ppm):
1.10 (d, 2JP,H ¼ 8.4 Hz, 9H, PCH3), 3.52 (t, r2JP,H þ 3JH,Hr ¼ 15.90 Hz, 2H,
PhCH2), 3.41 (t, r2JP,H þ 3JH,Hr ¼ 13.20 Hz, 2H, PhCH2), 7.62e6.82 (m,
14H, AreH). 31P NMR (CDCl3, 295.6 K, ppm): 56.9 (s,1P, PhCH2P),12.0
(s, 1P, PMe3). 13C NMR (C6D6, 300.1 K, ppm): 19.7 (dd,
4.7. X-ray structure determinations
Intensity data were collected on a Bruker SMART diffractometer
with graphite-monochromated Mo K
Crystallographic data for complexes 1e5 are summarized in Table 1.
The structures were solved by direct methods and refined with full-
matrix least-squares on all F2 (SHELXL-97) with non-hydrogen
atoms anisotropic.
1JP,C
þ
3JP,C ¼ 31.0 Hz, PCH3), 38.3 (d, 1JP,C ¼ 10.6 Hz, PCH2), 43.2 (d,
a radiation (l) 0.71073 Å).
1JP,C ¼ 29.4 Hz, PCH2),123.3 (s, CH),125.0 (s, CH),125.3(s, CH),125.8 (s,
CH), 129.2 (s, CH), 130.1 (s, CH), 131.0 (d, 2JP,C ¼ 9.8 Hz, C), 135.7 (d,
2JP,C ¼ 6.0 Hz, C), 146.5 (d, 2JP,C ¼ 3.0 Hz), 146.8 (d, 2JP,C ¼ 3.0 Hz, C).
4.5. Synthesis of 4
Acknowledgment
The solution of FeMe2(PMe3)4 (0.80 g, 2.05 mmol) in 20 ml THF
was added dibenzylphenylphosphine (0.60 g, 2.07 mmol) in 20 ml
THF. After stirring at room temperature for 48 h, the color of the
solution turned brown. The solution was stirred under 1 bar CO for
12 h. The color of the solution turned black. THF was evaporated in
vacuo and the residue was extracted by pentane and diethyl ether.
Crystallization at 0 ꢀC afforded complex 4 as yellow cubic crystals
suitable for X-ray diffraction analysis. Yield: 0.39 g of 4 (32.8%).
Analysis for 4 C27H35FeOP3, [found (calculated)]: C, 61.73 (61.60); H,
We gratefully acknowledge the support by NSF China No.
20972087.
Appendix A. Supplementary materials
CCDC-737241 (1), CCDC-737238 (2), CCDC-737243 (3), CCDC-
737239 (4) and CCDC-737242 (5) contain the supplementary
crystallographic data for this paper. These data can be obtained free
of charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
8.92 (8.99). m.p. 96e98 ꢀC (dec.). IR (Nujol):
n
¼ 1941 (C]O) cmꢁ1. 1H
NMR (C6D6, 673.2 K, ppm): 0.78 (d, 2JP,H ¼ 5.7 Hz, 18H, PCH3), 3.35
2
2
(d, JP,H ¼ 13.5 Hz, 2H, PhCH2), 3.44 (d, JP,H ¼ 6.0 Hz, 2H, PhCH2),
References
6.87e7.41 (m, AreH, 13H). 31P NMR (C6D6, 673.2 K, ppm): 11.6 (d,
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C
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