Coordination behavior of the 1,2,3-Triphosphaferrocene [Cp Fe(η5-P3C2(H)Ph)] with organometallic moieties

Article abstract of DOI:10.1021/om801118k

The reaction of the 1,2,3-triphosphaferrocene [Cp Fe(η⁵- P₃C₂(H)Ph)] (1) with the Lewis acidic complex [PtCl ₂(PEt₃)]₂ yields the monosubstituted derivative [Cp Fe(η⁵-P₃

Full text of DOI:10.1021/om801118k

Organometallics 2009, 28, 1075–1081
1075
Coordination Behavior of the 1,2,3-Triphosphaferrocene
[Cp′′′Fe(η5-P3C2(H)Ph)] with Organometallic Moieties
Shining Deng,† Christoph Schwarzmaier,† Manfred Zabel,† John F. Nixon,‡
Alexey Y. Timoshkin,§ and Manfred Scheer*,†
Institut fu¨r Anorganische Chemie, UniVersita¨t Regensburg, 93040 Regensburg, Germany, Chemistry
Department, School of Life Sciences, UniVersity of Sussex, Falmer, Brighton, BN19QJ, Sussex,
United Kingdom, and Department of Chemistry, St. Petersburg State UniVersity, UniVersity pr. 26,
198504 Old Peterhoff, St. Petersburg, Russian Federation
ReceiVed NoVember 24, 2008
The reaction of the 1,2,3-triphosphaferrocene [Cp′′′Fe(η5-P3C2(H)Ph)] (1) with the Lewis acidic complex
[PtCl2(PEt3)]2 yields the monosubstituted derivative [Cp′′′Fe(η5-P3C2(H)Ph){PtCl2(PEt3)}] (2), in which
the Pt moiety is located at the P atom adjacent to the C(H) group of the cyclo-P3C2 ring. Using an excess
of the Pt complex no multiple substitution occurs. In contrast, using [W(CO)5] units as Lewis acids
results in mono-, di-, and tricoordination at the cyclo-P3C2 ring. The products, [Cp′′′Fe(η5-
P3C2(H)Ph){W(CO)5}n] (n ) 1 (3), 2 (4), 3 (5)), have all been spectroscopically characterized, and the
substitution patterns of the experimentally found (mono- and disubstituted) isomers are found to be in
accordance with the energetically favored derivatives calculated by DFT methods. For these structures
the energetically favored rotational conformers have also been calculated. The energetically favored 2,3-
coordinated isomer 4b could be crystallized, and its structure and that of the tricoordinated derivative 5
were determined by X-ray diffraction methods.
Scheme 1. Types of Triphosphaferrocenes
Introduction
Phosphaferrocenes are an interesting class of compounds
because they combine fundamental aspects as well as applied
research.1 Within this class of compounds triphosphaferrocenes
are long-known compounds typified by the 1,2,4-triphospha-
ferrocene derivatives A (Scheme 1).2 In contrast, not long ago
the first 1,2,3-substituted derivatives B (R ) R′ ) Ph) were
synthesized.3 Recently, we succeeded in the synthesis of a new,
sterically less crowded type
B
derivative [Cp′′′Fe(η5-
P3C2(H)Ph)] (Cp′′′ ) η5-C5H2tBu3) (1).4
Scheme 2. Mono- and Disubstituted 1,2,4-Triphosphaferrocene
Complexes
The coordination chemistry behavior of type A compounds
was studied by the groups of Bartsch5,6 and Nixon7 (Scheme
2). By reacting [CpRFe(η5-P3C2tBu2)] (CpR ) Cp, Cp*) with
* To whom correspondence should be addressed. Tel: +49 941 9434441.
Fax: +49 941 9434439. E-mail: manfred.scheer@chemie.uni-regensburg.de.
† Universita¨t Regensburg.
‡ University of Sussex.
§ St. Petersburg State University.
(1) Mathey, F. In Phosphorus-Carbon Heterocyclic Chemistry: The Rise
of a New Domain; Mathey, F., Ed.; Elsevier: Oxford, 2001; p 767. Cornils,
B.; Herrmann, W. A., Eds. Homogeneous Catalysis with Organometallic
Compounds; VCH: Weinheim, 1996; Vols. 1 and 2. Dillon, K. B.; Mathey,
F.; Nixon, J. F. In Phosphorus: The Carbon Copy; Wiley: Chichester, 1998
Mathey, F. Angew. Chem. 2003, 115, 1617; Angew. Chem., Int. Ed. 2003,
42, 1578. Mathey, F. Coord. Chem. ReV. 1994, 137, 1.
(2) (a) Mu¨ller, C.; Bartsch, R.; Fischer, A.; Jones, P. G.; Schmutzler,
R. J. Organomet. Chem. 1996, 512, 141. (b) Bartsch, R.; Hitchcock, P. B.;
Nixon, J. F. J. Organomet. Chem. 1988, 340, C37. (c) Bartsch, R.; Hichcock,
P. B.; Nixon, J. F. J. Chem. Soc., Chem. Commun. 1987, 1146. (d) Mu¨ller,
C.; Bartsch, R.; Fischer, A.; Jones, P. G. J. Organomet. Chem. 1993, 435,
C16.
(3) Scherer, O. J.; Hilt, T.; Wolmersha¨user, G. Angew. Chem. 2000,
112, 1484; Angew. Chem., Int. Ed. 2000, 39, 1425. For the 1,2,3,4 derivative
cf.: Scheer, M.; Deng, S.; Scherer, O. J.; Sierka, M. Angew. Chem. 2005,
117, 3821; Angew. Chem., Int. Ed. 2005, 44, 3755.
(4) Deng, S.; Schwarzmaier, Ch.; Eichhorn, Ch.; Scherer, O. J.;
Wolmersha¨user, G.; Zabel, M.; Scheer, M. Chem. Commun. 2008, 4064.
(5) Mu¨ller, C.; Bartsch, R.; Fischer, A.; Jones, P. G.; Schmutzler, R. J.
Organomet. Chem. 1996, 512, 141.
metal carbonyl fragments the monosubstituted products A-1 are
obtained. The 31P NMR spectrum of the Cp*-containing complex
has been interpreted as the M(CO)5 fragment (M ) Cr, Mo,
W) undergoing a 1,2-shift between the two adjacent P atoms
of the η5-P3C2tBu2 ring in solution.5,6 However, in the Cp-
substituted derivative [CpFe(η5-P3C2tBu2){W(CO)5}]7 a rigid
structure in solution is described, revealing a W,P coupling
constant, whereas in the corresponding Cp*-substituted deriva-
(6) Mu¨ller, C.; Bartsch, R.; Fischer, A.; Jones, P. G. Polyhedron 1993,
12, 1383.
(7) Bartsch, R.; Hitchcock, P. B.; Nixon, J. F. J. Organomet. Chem.
1988, 340, C37.
10.1021/om801118k CCC: $40.75
2009 American Chemical Society
Publication on Web 01/29/2009

1076 Organometallics, Vol. 28, No. 4, 2009
Deng et al.
tives even at low temperature (-35 °C) no such coupling was
resolved.6 Interestingly, in all of these reactions it has been found
that only one metal carbonyl moiety is able to coordinate to
type A complexes. Additionally, several square-planar Pt(II)
complexes, such as A-2 and A-3, have been prepared by the
Nixon group, which are nonfluxional in solution and are formed
always as the corresponding cis isomers (Scheme 2), whereas
the bis-substituted products A-3 have a cis-trans stereochemistry.8,9
In contrast to the well-known coordination chemistry of type
A complexes no such studies have been done so far with the
1,2,3-substituted triphosphaferrrocenes of type B. Thus, the
questions arise (a) whether the coordination behavior of B would
be similar to type A complexes, (b) how many complex moieties
will be able to coordinate, and (c) are there preferred coordina-
tion patterns at the adjacent P atoms. Results of such investiga-
tions are reported herein.
comparison to the uncoordinated compound [Cp′′′Fe(η5-
P3C2(H)Ph)] (1) (δ(PB) ) 48.9 ppm) this signal is shifted about
10 ppm downfield. The signals attributed to PD are centered at
δ ) 17.4 ppm and have the smallest P-Pt coupling constant
(J(PD,Pt) ) 30 Hz), while the signal centered at δ ) -68.2
ppm, which reveals the largest P-P coupling constant (J(PM,PA)
) 517.5 Hz), is assigned to PM. The doublet at δ ) 9.9 ppm
belongs to PE, with a large coupling constant to the 195Pt nucleus
(J(PE,Pt) ) 3212.9 Hz). PE and PA must be located in
cis-positions, because of the relatively small coupling constant
(J(PE,PA) ) 28.0 Hz); otherwise the coupling between the atoms
PA and PE would be much larger (about 500 Hz). The sharp
signals representing these four phosphorus centers in the 31P{1H}
NMR spectrum of 2 at room temperature indicate that no
dynamic process occurs in solution.
Tungsten pentacarbonyl units were used as Lewis acids to
investigate whether all three phosphorus atoms of the 1,2,3-
triphosphaferrocene 1 can coordinate to metal centers simulta-
neously. Treating 1 with a THF solution containing 1 equiv of
[W(CO)5thf] gave after workup a reddish precipitate of 3
containing a mixture of two monosubstituted compounds, 3a
and 3b, in an almost 1:1 ratio (eq 2), as determined by its
31P{1H} NMR spectrum. Interestingly, from the crude reaction
mixture at low temperatures only a few red-orange crystals of
the disubstituted derivative 4b precipitated out.
Results and Discussion
When [Cp′′′Fe(η5-P3C2(H)Ph)] (1) is allowed to react with
[PtCl2(PEt3)]2 in a 1:1 stoichiometric ratio of the metal atoms
at room temperature, a brown powder of 2 was obtained (eq
1). In different reactions an excess of the Pt complex (1 and 2
equiv, respectively) was also used to react with 1. However,
inspecting the 31P NMR spectra of these crude reaction mixtures
showed, apart from some amounts of 2, no evidence of products
consisting of an intact 1,2,3-triphosphacyclopentadienyl ring,
suggesting that fragmentation of this moiety had occurred. A
possible explanation for the coordination of only one
[PtCl2(PEt3)] unit at the P3C2 ring of 1, as illustrated in eq 1, is
that the square-planar coordination mode of platinum is sterically
demanding. Due to the adjacent bulky Cp′′′ ligand, it is difficult
for a second [PtCl2(PEt3)] unit to coordinate at the cyclo-P3C2
ring of 1, as in the case of Cp-containing complex A-3, where
the PMe3-substituted Pt complex does (Scheme 2).9 The above-
mentioned possible fragmentation of the cyclo-P3C2 ring of 1
in the reaction with an excess of the coordination compound
was found very recently in a similar system when type A
complexes possessing the bulky Cp′′′ ligand are allowed to react
with an excess of CuCl, whereas the corresponding Cp complex
remains intact.10
Complex 2 is only slightly soluble in CH2Cl2 and THF, but
not in nonpolar solvents such as hydrocarbons. The mass
spectrum of 2 reveals a molecular ion peak minus two ethylene
groups of the PEt3 ligand.
Compound 4b is more efficiently obtained by the reaction of
1 with 2 equiv of [W(CO)5thf] (eq 3). However by using an
excess of [W(CO)5thf] (4 equiv) orange-red plates of 5 were
isolated in which all three P atoms are coordinated to [W(CO)5]
moieties (eq 4).
The 31P{1H} NMR spectrum of 2 contains four signals. The
doublet of doublet signal with 195Pt satellites centered at δ )
77.1 ppm is readily attributed to PA, which coordinates to the
Pt(II) center, revealing as expected a large coupling constant
J(PA,Pt) ) 4017.5 Hz. The coordination of PA (not PD) with Pt
was further confirmed by the P-H coupling constant (J(PA,Ha)
) 28.2, J(PD,Ha) ) 6.5 Hz) in the 31P NMR spectrum. In
(8) Al-Ktaifani, M.; Nixon, J. F.; Hitchcock, P. B. Unpublished results.
Al-Ktaifani, M. D. Phil. Thesis, Sussex University, 2004.
(9) Callaghan C. S. J., Nixon; J. F.; Hitchcock, P. B. Unpublished results.
Callaghan, C. S. J., D. Phil. Thesis, Sussex University, 1998.
(10) Deng, S.; Schwarzmaier, C.; Vogel, U.; Zabel, M.; Nixon, J. F.;
Scheer, M. Eur. J. Inorg. Chem. 2008, 4870.
Whereas the 31P NMR spectrum of the crude reaction mixture
of reaction 4 indicates the existence of only the tricoordinated
product 5, the corresponding spectrum of reaction 3 as well as

Coordination BehaVior of a 1,2,3-Triphosphaferrocene
Organometallics, Vol. 28, No. 4, 2009 1077
Figure 1. Molecular structure of 4b in the crystal (depicted at the
30% probability level; hydrogen atoms are omitted for clarity).
Selected bond lengths (Å) and angles (deg): P3-P2 2.112(2),
P2-P1 2.130(2), P3-C22 1.746(8), P1-C21 1.772(6), P3-W2
2.488(2), P2-W1 2.515(2), Fe-P3 2.332(2), Fe-P2 2.369(2),
Fe-P1 2.363(2), P1-P2-P3 100.54(11), P1-P2-W1 124.69(10),
P2-P3-W2 137.41(11), W2-P3-C22 122.7(3), P2-P3-C22
97.5(3).
that of the isolated compound 4 indicates that the major
component is the 1,3-substituted derivative 4a; however the 2,3-
isomer 4b as well as the 1,2-isomer 4c are also present in
solution as well as in the solid state (2:1:1 ratio). Interestingly,
only suitable single crystals of the 2,3-isomer 4b have been
obtained.
The products 3, 4, and 5 are soluble in CH2Cl2 and THF, but
dissolve only moderately in nonpolar solvents such as hydro-
carbons. They are air-sensitive and can be stored under an inert
atmosphere at low temperatures. In the EI-MS spectrum of 3
the molecular ion peak is observed, whereas for 4 the fragment
with the highest relative abundance is attributable to the
[Cp′′′Fe(P3C2(H)Ph)]+ cation. In addition, the cations
[Cp′′′Fe(P3C2(H)Ph)W(CO)5]+ and [Cp′′′Fe(P3C2(H)Ph)W]+ are
also detected and indicate the existence of 4. In the EI-MS
spectra of 5 no molecular ion was detected, but fragments such
as [Cp′′′Fe(η5-P3C2(H)Ph){W(CO)5}2]+, [Cp′′′Fe(η5-P3C2(H)-
Ph)W(CO)5]+, and [Cp′′′Fe(η5-P3C2(H)Ph)W]+ were found.
The solid-state structure of 4b has been established by X-ray
crystallography as shown in Figure 1. In complex 4b, two
phosphorus atoms in the cyclo-P3C2 ring coordinate to two
tungsten centers with an average P-W bond length of 2.502(2)
Å. The coordination geometry of the two phosphorus atoms is
distorted trigonal. Due to the repulsion between the two bulky
[W(CO)5] units, the two P-W bonds curl upward slightly from
the cyclo-P3C2 plane in order to keep the two [W(CO)5] units
away from each other (Figure 3). In comparison to the P2-P1
bond length (2.130(3) Å), the P3-P2 bond length, which carries
the coordinated [W(CO)5] units, is slightly shorter (2.112(3) Å).
The latter bond length is comparable with that in compound B
(R ) R′ ) Ph; 2.1287(14) and 2.1193(15) Å).3
Figure 2. Molecular structure of 5 in the crystal (depicted at the
30% probability level; hydrogen atoms are omitted for clarity).
Selected bond lengths (Å) and angles (deg): P1-P2 2.125(2),
P2-P3 2.121(2), P1-C17 1.755(7), P3-C16 1.751(6), P1-W1
2.5154(15), P2-W2 2.5135(17), P3-W3 2.5120(17), Fe-P1
2.3653(17), Fe-P2 2.3808(19), Fe-P3 2.3508(19), P1-P2-P3
99.45(9),P1-P2-W2130.49(8),W2-P2-P3129.43(8),W1-P1-P2
128.19(8), W3-P3-P2 133.92(9).
slightly longer than that in 4b (2.121(2) Å) and is almost the
same as that in complex [Cp′′′Fe(η5-P3C2Ph2)] B (2.124(2) Å).3
It is noteworthy that the P-P bond shows no significant change
after coordination of [W(CO)5] fragments. The average P-Fe
bond length in 5 (2.366 Å) is longer than that in 4b (2.355 Å).
All these bond length elongations in 5 compared to 4b may be
caused by steric effects.
The 31P{1H} NMR spectrum of complex 5 shows three
slightly broadened doublets of doublets of a ABM spin system
(PA ) P1, PB ) P3, PM ) P2). All signals shift upfield in
comparison to the uncoordinated complex 1 (Table 1). If 4 is
dissolved in CD2Cl2 in the 31P{1H} NMR spectrum at ambient
temperature, broadened signals of a ABM spin system of 4a as
the major component as well as poorly resolved multiplets of
4b and 4c showing no evidence for J(P,W) couplings are
observed. On lowering the temperature, the signals get sharper
and the corresponding 183W satellites are resolved. Whereas the
signals of the tungsten-substituted P atoms very slightly shifted
with temperature decrease, the signals of the uncoordinated P2
atom are significantly shifted to higher field (-82.4 f -88.5
The solid-state structure of 5 has also been established by
X-ray crystallography as shown in Figure 2.
Complex 5 possesses three phosphorus atoms in the phos-
pholyl ring coordinated to three different [W(CO)5] units. The
P2-W2 bond, which is coplanar with the cyclo-P3C2 ring, has
a bond length similar to the other two P-W bonds (P2-W2
2.5135(17), P1-W1 2.5154(15), P3-W3 2.5120(17) Å). Be-
cause of the repulsion of the two tBu groups on the cyclopen-
tadienyl ring, the P1-W1 and P3-W3 bonds are bent upward
from the cyclo-P3C2 plane (Figures 2 and 3). The average
distance of W-P in 5 (2.514(2) Å) is longer than that in 4b
(2.502(2) Å). The average P-P bond length (2.123(2) Å) is

1078 Organometallics, Vol. 28, No. 4, 2009
Deng et al.
Figure 3. Top view of the molecular structures of 4b and 5 to express the configurations in the solid state (ball-and-stick presentation,
hydrogen atoms are omitted for clarity).
Table 1. Comparison of Selected 31P NMR Spectroscopic Data of [Cp′′′Fe(η5-P3C2(H)Ph)] (1) and Its Tungsten Complexes 3a, 3b, 4a, 4b, 4c,
and 5 in CH2Cl2 at 293 Ka
δ(P1) [ppm]
δ(P2) [ppm]
δ(P3) [ppm]
J(P1,P2) [Hz]
J(P2,P3) [Hz]
J(P1,P3) [Hz]
[Cp′′′Fe(η5-P3C2(H)Ph)] 1
51.7
43.1
1.7
47.4
-25.6
-4.0
2.7
15.2
-32.4
16.8
48.9
45.7
1.1
427.1
425.9
432.4
466.9
512
399.6
471.3
445.7
468.0
412
0b
4.4
26.9
13.8
10
[Cp′′′Fe(η5-P3C2(H)Ph)3-{W(CO)5}] 3ac
[Cp′′′Fe(η5-P3C2(H)Ph)2-{W(CO)5}] 3bc
[Cp′′′Fe(η5-P3C2(H)Ph)1,3-{W(CO)5}2] 4aa c
-88.5
35.0
,
[Cp′′′Fe(η5-P3C2(H)Ph)2,3-{W(CO)5}2] 4ba c
7.6
7.8
-14.6
-16.7
-3.7
,
[Cp′′′Fe(η5-P3C2(H)Ph)1,2-{W(CO)5}2] 4ca c
512
446.7
412
412.4
30
,
[Cp′′′Fe(η5-P3C2(H)Ph){W(CO)5}3] 5c
-54.9
0b
a At 183 K. b As a consequence of the line broadening. c Labeling scheme cf. Scheme 3.
Scheme 3. Labeling Scheme of the Isomers at the
1,2,3-Triphospholyl Ring of the Complexes
present in comparable quantities if an equilibrium exists between
the isomers in solution. In contrast the 1-isomer 3c would be
much less favored by 18.2 kJ mol-1. Other rotational conformers
of 3c are even more disfavored (by 28-32 kJ mol-1). This
confirms the experimentally obtained results, in which only 3a
and 3b could be identified as the reaction products of reaction
1. Moreover, within the possible disubstituted isomers the 2,3-
isomer 4b is the thermodynamically most favored one, followed
by the 1,3-isomer 4a, which is only 0.8 kJ mol-1 higher in
energy, and the 1,2-isomer 4c, which is 7.3 kJ mol-1 less stable
than 4b (Figure 5). Interestingly, the observed energetically
favored rotational conformer of the 2,3-isomer is identical with
the fully structurally characterized product 4b. However, if
entropy change is taken into account, computations predict that
at room temperature isomers 3a and 4a will be slightly more
favored compared to 3b and 4b (Table 2). This agrees well with
experimental observation of both 3a, 3b and 4a, 4b in solution.
ppm). By simulation of the spectra of the individual compounds
and comparison with the proton coupled spectra the assignment
of the P atoms can be given (Table 1), and the data for all
isomers of compound 4 can be determined. In contrast, for 3a,b
already at 293 K the corresponding 183W satellites are revealed.
In 3a and 4a (both revealing the energetically favored
structures, cf. DFT calculations), the coordination of the P atoms
by [W(CO)5] moieties has not much influence on the chemical
shift of the corresponding P atoms in comparison with the
starting material, whereas the uncoordinated P atoms shift much
more. In contrast, in the energetically less favored derivatives
3b, 4b, and 4c and in the tricoordinated derivative 5 the
influence of the coordination on chemical shifts and coupling
constants is much more important. This might reflect the angle
and bond length effects in the sterically crowded derivatives.
DFT Computations. To gain more insight into the stability
of the formed derivatives and for any possible dissociation
behavior, density functional calculations have been carried out
for all possible isomers. For the monocoordinated compounds
3 the relative conformational stability of the three isomers with
respect to the orientation of the Cp′′′ ligand have been calculated.
According to the calculations, the 2-isomer 3b and the 3-isomer
3a are the most stable isomers, with 3a being disfavored by
only 1.3 kJ mol-1 (Figure 4). This small isomer energy
difference between 3b and 3a suggests that they should be
We have also estimated the influence of the solvent on the
isomer stability using a self-consistent reaction field approach.
CH2Cl2 solvent was modeled by the polarizable continuum
model (PCM). The extended 6-31++G** basis set, which
includes diffuse functions, has been applied. The energy
difference between isomers 4b and 4c decreases from 7.3 to
5.0 (B3LYP/6-31++G** SCRF single-point energy at B3LYP/
6-31G* optimized geometry) or 4.8 kJ mol-1 (B3LYP/6-
31++G** SCRF full optimization). Thus, we conclude that
CH2Cl2 as a solvent does not have a large influence on energy
differences between isomers. In the further discussion, only gas
phase data will be considered.
Our optimized geometries for the gas phase 4b and 5 are in
reasonable agreement with experimental X-ray data for the solid
compounds. Bond distances are slightly overestimated, which
is usual for the B3LYP level of theory. Theoretically predicted
P-P-P angles in 4b and 5 (101.0° and 99.4°) are in excellent

Coordination BehaVior of a 1,2,3-Triphosphaferrocene
Organometallics, Vol. 28, No. 4, 2009 1079
Figure 4. Optimized geometries of the most stable conformers of monoadducts 3. Relative energies in kJ mol-1. (a) [Cp′′′Fe(η5-P3C2(H)Ph)1-
{W(CO)5}] 3c; (b) [Cp′′′Fe(η5-P3C2(H)Ph)2-{W(CO)5}] 3b; (c) [Cp′′′Fe(η5-P3C2(H)Ph)3-{W(CO)5}] 3a. B3LYP/6-31G*(LANL2DZ basis
for W) level of theory.
Figure 5. Optimized geometries of the most stable conformers of the bis-adducts. Relative energies in kJ mol-1. (a) [Cp′′′Fe(η5-P3C2(H)Ph)1,2-
{W(CO)5}2] 4c; (b) [Cp′′′Fe(η5-P3C2(H)Ph)2,3-{W(CO)5}2] 4b; (c) [Cp′′′Fe(η5-P3C2(H)Ph)1,3-{W(CO)5}2] 4a. B3LYP/6-31G*(LANL2DZ
basis for W) level of theory.
Table 2. Thermodynamic Characteristics for the Gas Phase Processes at the B3LYP/6-31G*(LANL2DZ basis for W) Level of Theory
∆E
∆H°298
∆S°298
∆G°298
∆G°398
process
kJ mol-1
kJ mol-1
J mol-1 K-1
kJ mol-1
kJ mol-1
3c ) 3a
3b ) 3a
-16.9
1.3
122.6
140.8
139.4
12.4
30.6
29.2
0.8
-6.4
115.5
116.9
5.3
6.7
99.0
106.2
99.8
-11.2
-3.9
-10.4
110.2
-17.7
0.1
116.6
134.4
134.3
13.5
31.2
31.2
0.5
-6.9
109.8
109.9
6.7
6.8
92.9
100.3
93.5
-10.2
-2.8
-9.7
103.1
6.8
8.8
-19.7
-2.5
62.7
79.8
82.4
7.3
24.5
27.0
-20.4
-3.4
44.6
61.5
65.0
5.2
22.2
25.6
3c ) 1 + W(CO)5
181.0
183.0
174.2
20.7
22.7
13.9
15.4
24.3
192.3
201.1
32.0
40.8
204.5
195.6
219.9
44.2
35.3
59.6
160.3
3b ) 1 + W(CO)5
3a ) 1 + W(CO)5
3c + THF ) 1 + [W(CO)5thf]
3b + THF ) 1 + [W(CO)5thf]
3a + THF ) 1 + [W(CO)5thf]
4b ) 4a
-4.1
-14.1
52.6
-5.6
-16.5
33.3
4c ) 4a
4b ) 3b + W(CO)5
4b ) 3a + W(CO)5
50.0
29.9
4b + THF ) 3b + [W(CO)5thf]
4b +THF ) 3a + [W(CO)5thf]
5 ) 4b + W(CO)5
-2.8
-5.4
32.0
42.0
27.9
-23.4
-13.3
-27.4
55.4
-6.0
-9.4
11.6
22.5
6.0
-27.8
-16.9
-33.4
39.3
5 ) 4c + W(CO)5
5 ) 4a + W(CO)5
5 + THF ) 4b + [W(CO)5thf]
5 + THF ) 4c + [W(CO)5thf]
5 + THF ) 4a + [W(CO)5thf]
[W(CO)5thf] ) W(CO)5 + THF
agreement with experimental values 100.54(11)° and 99.45(9)°.
The calculated mean W-P bond distance in 5 (2.576 Å) is
longer than that in 4b (2.561 Å), in agreement with experimental
observations for the solid-state compounds.
Thermodynamic characteristics of complex dissociation pro-
cesses are summarized in Table 2. The [W(CO)5] moiety is quite
strongly bound to phosphorus and P-W bond dissociation
energies are in the range 99-141 kJ mol-1. The stability of the
complexes decreases with increasing numbers of [W(CO)5] units
(141 > 116 > 99 kJ mol-1 for the most stable isomers 3b, 4b,
and 5, respectively).
If THF is present in the solution, formation of the
[W(CO)5thf] complex should be taken into account. These data
are also summarized in Table 2. The thf-W(CO)5 bond energy
is larger compared to P-W bonds in tris-adducts, but smaller
than the one found in bis- and monoadducts. Thus, the tris-
complex 5 reacts with THF exothermically, while reactions of
THF with bis-adducts 4 and monoadducts 3 are endothermic.

1080 Organometallics, Vol. 28, No. 4, 2009
Deng et al.
Table 3. Crystallographic Data for 4b and 5
4b
5 · CH2Cl2
empirical formula
fw
C35H35FeO10P3W2
1132.07
C41H37FeO15P3W3Cl2
1540.89
temperature
wavelength
cryst syst
space group
unit cell dimens
123(1) K
1.54184 Å
monoclinic
C2/c
a ) 32.8307(5) Å
b ) 11.56806(18) Å
c ) 21.5150(3) Å
123(1) K
1.54184 Å
triclinic
j
P1
a ) 11.4506(6) Å
b ) 12.8637(7) Å
c ) 18.9303(9) Å
R ) 78.287(4)°
ꢀ ) 78.727(4)°
γ ) 65.317(5)°
2461.6(2) Å3
ꢀ ) 107.9860(17)
volume
7771.8 (2) Å3
Z
8
2
density calcd
absorp coeff
F(000)
1.935 Mg/m3
2.079 Mg/m3
15.281 mm-1
4352
17.411 mm-1
1460
cryst size
θ range for data collection
index ranges
0.03 × 0.06 × 0.14 mm
0.200 × 0.170 × 0.130 mm
2.8 to 51.5°
2.40 to 62.17°
-33 e h e 27, -11 e k e 10,
-21 e l e 21
11 470
4150 [R(int) ) 0.032]
97.3%
-13 e h e 13, -14 e k e 14,
-20 e l e 21
23 456
7607 [R(int) ) 0.0219]
97.8%
no. of reflns collected
no. of indep reflns
completeness to θ
absorp corr
multiscan
multiscan
max. and min. transm
no. of data/restraints/params
goodness-of-fit on F2
final R indicesa [I > 2σ(I)]
R indicesb (all data)
largest diff peak and hole
1.0000 and 0.37878
4150/0/466
1.066
R1 ) 0.0325, wR2 ) 0.0693
R1 ) 0.0431, wR2 ) 0.0743
1.02 and -0.92 e A-3
1.00000 and 0.61563
7607/0/595
1.034
R1 ) 0.0343, wR2 ) 0.0848
R1 ) 0.0370, wR2 ) 0.0868
2.298 and -2.830 e A-3
b
a R1 ) ∑||Fo| - |Fc||/∑|Fo|. wR2 ) [∑w(Fo - Fc2)2]/[∑(Fo )2.
2
2
However, if entropy change is taken into account, standard
Gibbs energies for the reaction with THF are negative for both
5 (-13 kJ mol-1) and 4b (-3 kJ mol-1) and positive for 3b
(25 kJ mol-1). Since these reactions proceed with no change in
the number of gaseous molecules, the trend in thermodynamic
characteristics found for the gas phase should also be retained
in CH2Cl2 solution. Due to small absolute values of the standard
Gibbs energies, a shift of the equilibrium toward formation of
5 is expected with an excess of [W(CO)5thf].
predicted by DFT computations. It seems likely that the
broadened signals of the 31P NMR spectra at room temperature
are due to the rotation of the Cp′′′ ring of the ferrocenes. The
static behavior of all the complexes described in this paper
sharply contrasts with the behavior of η1-bonded 1,2,4-P3C2R2
ring complexes of a variety of metals, which show a strong
tendency to undergo 1,2 shift and ring inversion dynamics.11
Experimental Section
Conclusions
General Procedures. All manipulations were performed under
an atmosphere of dry nitrogen using standard glovebox and Schlenk
techniques. Solvents were purified and degassed by standard
procedures. The starting material 1 was prepared according to our
published methods;4 [PtCl2PEt3]2 was synthesized from PtCl2 and
[PtCl2(PEt3)2].12,13 Solution NMR spectra were recorded on a
Bruker AVANCE 400 spectrometer (1H: 400.13 MHz, 31P: 161.976
MHz, with δ [ppm] referenced to external SiMe4 (1H) and H3PO4
(31P)). Mass spectra were performed using a Finnigan MAT 95. IR
spectra were recorded on a Varian FTS 2000, and elemental
analyses were performed with an Elementar Vario EL III.
Syntheses of [Cp′′′Fe(µ,η5:η1-P3C2(H)Ph){PtCl2(PEt3)}] (2).
A solution of [Cp′′′Fe(η5-P3C2PhH)] (20 mg, 0.041 mmol) and
[(PtCl2PEt3)2] (16 mg, 0.02 mmol) in CH2Cl2 (10 mL) was stirred
for 1 h at room temperature. An orange-red solution was formed.
After concentration under reduced pressure to about one-third of
the original volume, hexane (5 mL) was added and a brown powder
was obtained (20 mg, 55.9% yield). 31P{1H} NMR (CD2Cl2, 293
K, 161.98 MHz): δ(PA) ) 77.1 ppm, δ(PD) ) 17.4 ppm, δ(PE) )
9.9 ppm, δ(PM) ) -68.2 ppm, J(PD,PM) ) 420.8 Hz, J(PA,PM) )
We have shown in reactions of the 1,2,3-triphosphaferrocene
with organometallic Lewis acids that a particular steric influence
of the adjacent tri-tert-butylcyclopentadienyl ligand as well as
the organic substituents at the triphospholyl ring exists. Thus,
the square-planar complex moiety [PtCl2(PEt3)] gives only a
monocoordinated complex 2, whereas the more flexible
[W(CO)5] unit yields all types of substitution patterns depending
on the used stoichiometry. Even if an excess of [W(CO)5thf] is
used, the tricoordinated derivative 5 is obtained. Interestingly,
in the 1:1 stoichiometric reaction only the energetically favored
monocoordinated derivatives 3a and 3b are obtained, as DFT
calculations incorporating all possible conformational rotamers
have shown. In a 1:2 reaction all possible dicoordinated
derivatives 4a-c are detected. However, the energetically
favored 1,3-coordinated isomer 4a is the main product of the
reaction. In general, the P atom adjacent to the CH unit of the
1,2,3-triphospholyl ring is favored for coordination for steric
reasons. The room-temperature 31P NMR spectra of the mono-
coordinated derivatives 3 and the variable-temperature NMR
studies for complexes 4 have shown that there is no dynamic
behavior involving movement of the [W(CO)5] moieties between
two adjacent P atoms of the η5-P3C2(H)Ph ring. This observation
is in accordance with strong W-P bonding in the complexes
(11) Hofmann, M.; Clark, T.; Heinemann, F. W.; Zenneck, U. Eur.
J. Inorg. Chem. 2008, 2225, and references therein.
(12) McDermott, J. X.; White, J. F.; Whitesides, G. M. J. Am. Chem.
Soc. 1976, 98, 6521.
(13) Hartley, F. R. Organomet. Chem. ReV. A 1970, 6, 119.

Coordination BehaVior of a 1,2,3-Triphosphaferrocene
Organometallics, Vol. 28, No. 4, 2009 1081
517.5 Hz, J(PA,PE) ) 28.0 Hz, J(PA,PD) ) 4.7 Hz, J(PD,Pt) ) 30
Hz, J(PM,Pt) ) 149.0 Hz, J(PA,Pt) ) 4017.5 Hz, J(PE,Pt) ) 3212.9
Hz. 31P NMR (CD2Cl2, 300 K, 161.98 MHz): J(Pa,Ha) ) 6.5 Hz,
J(Pc,Ha) ) 28.2 Hz. 1H NMR (C6D6, 298 K, 400.13 MHz): δ 1.29
(s, 9H), 1.38 (s, 9H), 1.45 (s, 9 H), 2.10 (m, 15H, Et), 4.18 (dd,
1H, Cp′′′), 4.61 (dd, 1H, Cp′′′), 6.18 (ddd, 1H, P3C2-ring), 7.70
(m, 3H, C6H5), 7.77 (m, 2H, C6H5) ppm. ESI-MS (MeCN, RT):
m/z ) 750 [Cp′′′Fe(P3C2PhH)PtCl2]+ (3.6%), 768 [Cp′′′Fe-
(P3C2PhH)PtPEt2]+ (1.7%), 812 [Cp′′′Fe(P3C2PhH)PtCl2PEt(H)2]+
(1.4%).
Synthesis of [{Cp′′′Fe(µ,η5:η1:η1-P3C2(H)Ph)}{W(CO)5}3]
(5). A solution of [Cp′′′Fe(η5-P3C2(H)Ph)] (20 mg, 0.041 mmol)
and [W(CO)5thf] (60 mg, 0.16 mmol) in THF (25 mL) was stirred
for 16 h at room temperature. After removal of all solvents in
vacuum the residue was dissolved in about 3 mL of dichloromethane
and the solution was kept at -28 °C for 1 week. Orange-red crystals
of 5 were obtained (20 mg, 33.4% yield). 31P{1H} NMR (CD2Cl2,
293 K, 161.98 MHz, ABM spin system): δ(PA) 2.7 ppm, δ(PM)
-54.9 ppm, δ(PB) -3.7 ppm, J(PA,PM) ) 412.4 Hz, J(PM,PB) )
446.7 Hz, J(PA,W) ) 289 Hz, J(PM,W) ) 202 Hz, J(PB,W) ) 231
Syntheses of [{Cp′′′Fe(µ,η5:η1:η1-P3C2(H)Ph)}W(CO)5] (3a,
3b). A solution of [Cp′′′Fe(η5-P3C2(H)Ph)] (24 mg, 0.05 mmol)
and [W(CO)5thf] (0.05 mmol) in THF (5 mL) was stirred for 1 h
at room temperature. The color of the reaction solution changed
from red to red-orange. After removal of all solvent in vacuum,
the residue was dissolved in about 2 mL of dichloromethane, the
solution was kept at -28 °C for 1 week, and red microcrystals
were obtained (20 mg, 51% yield). EI-MS (70 eV): m/z ) 484
[Cp′′′Fe(P3C2PhH)]+ (100%), 667 [Cp′′′Fe(P3C2PhH)W]+ (16%),
807 [Cp′′′Fe(P3C2PhH)W(CO)5]+ (7%). Anal. Calcd for
C30H35FeO5P3W: C, 44.58; H 4.36. Found: C, 44.13; H, 4.01. 3a:
31P{1H} NMR (CD2Cl2, 293 K, 161.98 MHz, ABM spin system):
δ(PA) 43.1 ppm, δ(PB) ) 45.7 ppm, δ(PM) -32.4 ppm, J(PA,PM)
) 425.9 Hz, J(PM,PB) ) 471.3 Hz, J(PA,PB) ) 44 Hz, J(PB,W) )
241.4 Hz. 3b: 31P{1H} NMR (CD2Cl2, 293 K, 161.98 MHz, ABM
spin system): δ(PA) 1.7 ppm, δ(PB) 1.1 ppm, δ(PM) 16.8 ppm,
J(PA,PM) ) 432.4 Hz, J(PM,PB) ) 445.7 Hz, J(PA,PB) ) 26.9 Hz,
1
Hz. H NMR (CD2Cl2, 293 K, 400.13 MHz): δ 1.38(s, 9H), 1.65
(s, 9H), 1.67 (s, 9H), 4.30 (dd, 2H, Cp′′′), 5.85 (ddd, 1H, P3C2-
ring), 7.35 (m, 3H, C6H5), 7.80 (m, 2H, C6H5) ppm. IR (CH2Cl2):
ν(CO) [cm-1]: 2055, 1942, 1908. EI-MS (70 eV): m/z ) 484
[Cp′′′Fe(P3C2PhH)]+ (100%), 668 [Cp′′′Fe(P3C2PhH)W]+ (54%),
807 [Cp′′′Fe(P3C2PhH)W(CO)5]+ (17%), 1131 [{Cp′′′Fe(P3C2PhH)}-
{W(CO)5}2]+ (5%). Anal. Calcd for C40H35FeO15P3W3: C, 33.00;
H 2.42. Found: C, 33.42; H, 2.77.
X-ray Structure Analysis. The crystal structure analyses were
performed on an Oxford Diffraction Gemini Ultra diffractometer
with Cu KR radiation (λ ) 1.54184). Compound 5 crystallizes with
1 equiv of CH2Cl2 per formula unit. The structures were solved by
direct methods with the program SHELXS-97,14a and full matrix
least-squares refinement on F2 in SHELXL-9714b was performed
with anisotropic displacements for non-H atoms. The hydrogen
atoms at the carbon atoms were located in idealized positions and
refined isotropically according to the riding model. Empirical
absorption corrections using spherical harmonics, implemented in
the CrysAlis-RED program of Oxford Diffraction, were applied.
Computational Details. All structures were fully optimized and
verified with subsequent vibrational analysis to be minima on the
potential energy surface. Density functional theory in the form of
the hybrid B3LYP15 functional was used together with the standard
full-electron 6-31G* basis set. The LANL2DZ ECP basis set of
Hay and Wadt16 was used for W. The Gaussian 0317 suite of
programs was used throughout. Solvent effects (CH2Cl2) were
estimated using the self-consistent reaction field approach in a
polarizable continuum model (PCM) approximation with the
6-31++G** basis set as implemented in the Gaussian 03 program
package.
1
J(PM,W) ) 214.8 Hz. H NMR (CD2Cl2, 300 K, 400.13 MHz): δ
1.20/1.23 (s, 9H), 1.40/1.42 (s, 9H), 1.50/1.52 (s, 9 H), 4.32 (dd,
2H, Cp′′′), 4.56 (dd, 2H, Cp′′′), 5.75 (ddd, 2H, P3C2-ring), 7.32
(m, 6H, C6H5), 7.80 (m, 4H, C6H5) ppm.
[{Cp′′′Fe(µ,η5:η1:η1-P3C2(H)Ph)}{W(CO)5}2] (4). A solution
of [Cp′′′Fe(η5-P3C2(H)Ph)] (20 mg, 0.041 mmol) and [W(CO)5thf]
(30 mg, 0.08 mmol) in THF (15 mL) was stirred for 1 h at room
temperature. The color of the reaction solution changed from red
to red-orange. After removal of all solvent in vacuum, the residue
was dissolved in about 2 mL of dichloromethane. By adding
n-hexane an orange solid of 4 (25 mg, 48% yield) was precipitated.
If the CH2Cl2 solution was kept at -28 °C for 1 week, orange-red
crystals of 4b were obtained: IR (CH2Cl2): ν(CO) [cm-1]: 2078
(w), 2072 (m), 1975 (sh), 1953 (s, br). EI-MS (70 eV): m/z ) 484
[Cp′′′Fe(P3C2PhH)]+ (100%), 667 [Cp′′′Fe(P3C2PhH)W]+ (42%),
807 [Cp′′′Fe(P3C2PhH)W(CO)5]+ (66%), 1131 [{Cp′′′Fe(P3C2PhH)}-
{W(CO)5}2]+ (35%). Anal. Calcd for C35H35FeO10P3W2: C, 37.13;
H 3.12. Found: C, 36.89; H, 3.81. 4a: 31P{1H} NMR (CD2Cl2, 293
K, 161.98 MHz, ABM spin system): δ(PA) 47.3 ppm, δ(PB) 36.0
ppm, δ(PM) -82.4 ppm; 31P{1H} NMR (CD2Cl2, 183 K, 161.98
MHz, ABM spin system): δ(PA) 47.4 ppm, δ(PM) -88.5 ppm, δ(PB)
35.0 ppm, J(PA,PM) ) 466.9 Hz, J(PM,PB) ) 468.0 Hz, J(PA,PB) )
13.8 Hz, J(PA,183W) ) 244 Hz, J(PB,183W) ) 244 Hz. 31P{1H} NMR
(THF-d8/CH2Cl2 (3:1), 293 K, 161.98 MHz, ABM spin system):
δ(PA) 48.5 ppm, δ(PB) 38.1 ppm, δ(PM) -81.0 ppm, J(PA,PM) )
462 Hz, J(PM,PB) ) 466 Hz, J(PA,PB) ) 14.9 Hz, J(PA,183W) )
250 Hz, J(PB,183W) ) 250 Hz. 4b: 31P{1H} NMR (CH2Cl2, 183 K,
161.98 MHz, ABM spin system): δ(PA) -25.6 ppm, δ(PB) -14.6
ppm, δ(PM) 7.6 ppm, J(PA,PM) ) 512 Hz, J(PM,PB) ) 412 Hz,
J(PA,PB) ) 10 Hz, J(PA,183W) ) 244 Hz, J(PB,183W) ) 244 Hz. 1H
NMR (CD2Cl2, 293 K, 400.13 MHz): δ 1.19 (s, 9H), 1.22 (s, 9H),
1.39 (s, 9 H), 4.28 (dd, 2H, Cp′′′), 5.80 (ddd, 1H, P3C2-ring), 7.35
(m, 3H, C6H5), 7.80 (m, 2H, C6H5) ppm. IR (CH2Cl2): ν(CO)
[cm-1]: 2076, 1975, 1950. 4c: 31P{1H} NMR (CH2Cl2, 183 K,
161.98 MHz, ABM spin system): δ(PA) -4.0 ppm, δ(PB) -16.7
ppm, δ(PM) 7.8 ppm, J(PA,PM) ) 512 Hz, J(PM,PB) ) 412 Hz,
J(PA,PB) ) 30 Hz, J(PA,183W) ) 300 Hz, J(PB,183W) ) 244 Hz.
Acknowledgment. The authors are grateful to the Deut-
sche Forschungsgemeinschaft and the Fonds der Chemischen
Industrie for financial support. The Alexander von Humboldt
Foundation is gratefully acknowledged for a Research Award
(to J.F.N.).
Supporting Information Available: Experimental and simulated
31P NMR spectra of the products, complete ref 17 citation, and
computational details (optimized xyz coordinates and total energies
of considered compounds). This material is available free of charge
via the Internet at http://pubs.acs.org.
OM801118K
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