Phosphaalkenes R1C(O)-P=C(NMe2)2 (R 1=Ph, 4-EtC6H4): Versatile reagents for 1,3-dipolar cycloadditions to phosphenium complexes [Cp(CO)2M = PPh2] (M = Mo, W)

Article abstract of DOI:10.1002/ejic.200700440

Reaction of [Cp(CO)₂M = PPh₂] [where M = Mo (2a), W (2b)] with an excess of the phosphaalkenes arylC(O)P=C(NMe₂) ₂ [where aryl = Ph (3), 4-EtC₆H₄ (5)] afforded the metallophosphaalkenes [Cp

Full text of DOI:10.1002/ejic.200700440

FULL PAPER
DOI: 10.1002/ejic.200700440
Phosphaalkenes R1C(O)–P=C(NMe2)2 (R1=Ph, 4-EtC6H4): Versatile Reagents
for 1,3-Dipolar Cycloadditions to Phosphenium Complexes
[Cp(CO)2M = PPh2] (M = Mo, W)
Lothar Weber,*[a] Gabriel Noveski,[a] Stefan Uthmann,[a] Hans-Georg Stammler,[a] and
Beate Neumann[a]
Keywords: Phosphaalkenes / Phosphenium Complexes / Molybdenum / Tungsten
Reaction of [Cp(CO)2M = PPh2] [where M = Mo (2a), W (2b)]
with an excess of the phosphaalkenes arylC(O)P=C(NMe2)2
[where aryl = Ph (3), 4-EtC6H4 (5)] afforded the metallophos-
phaalkenes [Cp(CO)2Ma–P=C(aryl)–O–PbPh2(Ma–Pb)] [where
M = Mo, aryl = Ph (4a); M = W, aryl = Ph (4b); M = Mo,
aryl = 4-EtC6H4 (6a); M = W, aryl = 4-EtC6H4 (6b)] as orange
crystals. Compounds 4a,b and 6a,b were characterized by
means of spectroscopy (IR, 1H, 13C and 31P NMR spec-
troscopy and MS). Moreover, the molecular structures of 3,
4a, and 6b were determined by X-ray diffraction analysis.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2007)
Introduction
During the course of our studies on phosphaalkenes R–
P=C(NMe2)2 (R = tBu, Cy, Ph), we observed a facile metal-
assisted cleavage of the PC multiple bond and the formal
transfer of phosphanediyls (RP) on suitable complexes with
electrophilic ligands.[1] Thus, reaction with selected Fischer
carbene complexes gave rise to the formation of coordina-
tion compounds I with novel η1-phosphaalkene ligands,[2]
whereas treatment with vinylidene complexes resulted in the
formation of η2(P,C)-phosphaallene complexes II.[3] η3-1,2-
Diphosphaallyl complexes III were obtained from the com-
bination of phosphaalkenes and phosphavinylidene com-
plexes.[4] Only recently we disclosed the generation of η2-
diphosphanyl complexes IV by reacting phosphaalkenes
and phosphenium complexes[5] (Scheme 1).
Results and Discussion
The purpose of this work was to study the reactivity of
the P-benzoylphosphaalkenes PhC(O)P=C(NMe2)2 (3)[6]
and 4-EtC6H4C(O)P=C(NMe2)2 (5) with the phosphenium
complexes [Cp(CO)2M = PPh2] (2a: M = Mo; 2b: W). The
latter were generated in situ by the dehydrochlorination of
the functionalized phosphane complexes [Cp(CO)2ClMP-
(H)Ph2][7] (1a: M = Mo; 1b: W) with diazabicycloundecene
Scheme 1. Phosphanediyl-transfer from phosphaalkenes onto se-
(DBU). Phosphaalkene 5 was synthesized as a yellow lected organometallic electrophiles.
powder in 81% yield from 4-ethylbenzoylchloride and
[8]
Me3SiP=C(NMe2)2 (Scheme 2).
Treatment of freshly prepared complexes 2a,b with an
excess of the phosphaalkenes in toluene solution over a
temperature range of –30 to 20 °C afforded orange crystal-
line metallophosphaalkenes 4a,b and 6a,b in modest yields
(Scheme 3).
[a] Fakultät für Chemie der Universität Bielefeld
Universitätsstrasse 25, 33615 Bielefeld, Germany
Fax: +49-521-106-6146
E-Mail: lothar.weber@uni-bielefeld.de
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L. Weber, G. Noveski, S. Uthmann, H.-G. Stammler, B. Neumann
FULL PAPER
PPh2 unit. In keeping with the increased donor capability
of the phosphaalkenyl group, the resonance of the carbonyl
ligand in its trans disposition is attributed to the more de-
shielded signal. The [M(CO)2] group gives rise to two in-
tense bands in the IR spectra at ν = 1935–1943 and 1864–
˜
1881 cm–1, which are due to the symmetric and asymmetric
CO stretching vibrations. Interestingly, the novel bidentate
chelating ligand exhibits a decreased donor capacity relative
to the η2-diphosphanido ligand in complexes of the type
Scheme 2. Preparation of 2a,b and 5.
[Cp(CO)2MPR1–PR2R3], IV (ν
= 1918–1933; 1837–
˜
1849 cm–1).[5] The carbonyl vibration of the aryl group in
precursor 4 was observed at ν = 1535 cm–1, and does not
˜
show up in the products any longer, which means that it
was involved in a cycloaddition process.
X-ray Structural Investigations
Single crystals of phosphaalkene 2 suitable for X-ray dif-
fraction studies were grown from n-pentane at –30 °C. The
analysis (Figure 1, Table 1) shows a benzoyl-stabilized car-
benium phosphanide, in which the planar carbenium center
C(8) (sum of angles is 359.6°) displays multiple bonding to
planarly configured nitrogen atoms [N(1)–C(8)
1.344(2) Å, N(2)–C(8) = 1.356(2) Å].
=
Scheme 3. Synthesis of metallophosphaalkenes 4a,b and 6a,b.
Isolation of the products was effected by column
chromatography on Florisil with mixtures of pentane/di-
ethylether as the eluents. Subsequent crystallization fur-
nished analytically pure compounds.
The 31P{1H} NMR spectra of 4a and 6a show two dou-
blets. The tetracoordinate P atoms give rise to signals at δ
= 199.9 and 198.7 ppm, whereas the dicoordinate P atoms
are observed at markedly lower field [4a: 235.5 (d); 6a:
225.9 (d)] with PP coupling constants of 21.8 and 20.7 Hz,
respectively. As expected, the corresponding doublets in
tungsten complex 4b and 6b are more shielded and appear
at δ = 170.7 (d, PPh2) and 170.1 (d, PPh2) ppm and δ =
209.4 (d, P=C) and 199.9 (d, P=C) with PP coupling con-
Figure 1. Molecular crystal structure of 2. Selected bond lengths
[Å] and angles [°]: P(1)–C(8) 1.800(1), P(1)–C(7) 1.806(1), O(1)–
C(7) 1.240(2), N(1)–C(8) 1.344(2), N(1)–C(9) 1.462(2), N(1)–C(10)
1.468(2), N(2)–C(8) 1.356(2), N(2)–C(11) 1.461(2), N(2)–C(12)
1.457(2), C(6)–C(7) 1.511(2). C(8)–P(1)–C(7) 101.34(6), C(8)–N(1)–
C(9) 123.0(1), C(8)–N(1)–C(10) 122.5(1), C(9)–N(1)–C(10)
stants of 21.8 and 22.5 Hz. Only tetracoordinate P atoms 113.4(1), C(8)–N(2)–C(11) 122.9(1), C(8)–N(2)–C(12) 123.3(1),
1
of 4b and 6b exhibit 183W satellites with JWP = 329.3 and
C(11)–N(2)–C(12) 113.8(1), N(1)–C(8)–N(2) 116.8(1), N(1)–C(8)–
P(1) 124.6(1), N(2)–C(8)–P(1) 118.2(1), P(1)–C(7)–O(1) 127.0(1),
O(1)–C(7)–C(6) 118.0(1), C(6)–C(7)–P(1) 115.0(1).
330.4 Hz.
In the 13C{1H} NMR spectra of the products, the carbon
atoms of the P=C bonds give rise to doublets of doublets
The former P=C bond of the precursor [cf.
HP=C(NMe2)2; d(P=C) = 1.740(1) Å] is markedly length-
ened to 1.800(1) Å. A bond length of 1.806(1) Å is found
between the phosphorus atom and the carbon atom of the
carbonyl group in 2, which compares well with the other
in the typical low field region [4a: δ = 193.6 ppm (1JPC
=
=
=
=
2
85.6 Hz, JPC = 17.8 Hz); 4b: δ = 192.9 ppm (1JPC
2
82.9 Hz, JPC = 18.2 Hz); 6a: δ = 194.1 ppm (1JPC
2
86.2 Hz, JPC = 17.5 Hz); 6b: δ = 193.4 ppm (1JPC
82.8 Hz, JPC = 18.4 Hz)]. The 13C{1H} NMR spectra of PC bond of the molecule. Both bonds are best regarded as
4a,b and 6a,b show in the region of the carbonyl carbon single bonds. The bonds between the phosphorus atom and
atoms two markedly separated resonances at δ = 223.9 (s; the carbon atoms of both carbonyl groups in bis(pivaloyl)-
4b, 6b) and δ = 231.5 (d, 2JPC = 17.5 Hz; 4b), 231.8 (d, 2JPC phenylphosphane [tBuC(O)]2PPh, however, are much
= 18.4 Hz; 6b) and in the molybdenum compounds at δ = longer [1.893(4) and 1.922(5) Å].[9] The CO double bond in
2
2
2
234.3 (d, JPC = 12.7 Hz), 241.3 (d, JPC = 26.4 Hz) and at 2 [1.240(1) Å] is slightly elongated relative to the CO bonds
2
2
234.3 (d, JPC = 12.1 Hz), 241.5 (d, JPC = 25.6 Hz) for 4a in [tBuC(O)]2PPh [1.201(6) and 1.217(6) Å]. The backbone
and 6a, respectively. We assign the resonances at higher of the compound defined by the atoms N(2), C(8), P(1),
field to the carbonyl group in the trans disposition of the C(7), and C(6) deviates severely from a plane, as indicated
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Eur. J. Inorg. Chem. 2007, 4011–4016

Phosphaalkenes: Reagents in 1,3-Dipolar Cycloaddition Reactions
Table 1. Crystal data and data collection parameters.
FULL PAPER
Compound
3
4a
6b
Empirical formula
Mr [gmol–1]
Crystal dimensions [mm]
Crystal system
Space group
a [Å]
b [Å]
c [Å]
α [°]
β [°]
C12H17N2OP
236.25
1.1ϫ1.0ϫ0.6
monoclinic
C2/c
18.295(7)
7.867(2)
17.562(5)
90
96.62(3)
90
2510.8(14)
8
C26H20MoO3P2
538.30
0.27ϫ0.16ϫ0.07
monoclinic
P21/n
9.2032(7)
16.8512(9)
14.8462(9)
90
95.457(5)
90
C28H24O3P2W
654.26
0.30ϫ0.30ϫ0.24
triclinic
¯
P1
8.6693(10)
11.5833(14)
13.0253(3)
90.573(6)
103.736(5)
101.577(16)
1242.4(2)
2
γ [°]
V [Å3]
2292.0(3))
4
1.560
Z
ρcalcd. [gcm–3]
1.250
0.201
1.749
4.806
µ [mm–1]
0.738
F(000)
θ [°]
refl. collected
refl. unique
R (int)
Refined parameters
GOF
1008
2.24–30.00
3720
3619
0.0262
213
1088
3.01–27.50
37211
5237
0.0294
289
1.079
640
3.23–30.00
45461
7238
0.0553
309
1.091
1.067
RF [IϾ2 σ (I)]
wRF2 [all Data]
∆ρ max/min [eÅ–3]
0.0404
0.1073
0.521/–0.350
0.0215
0.0489
0.406/–0.496
0.0155
0.0388
0.686/–0.771
by the torsion angles O(1)–C(7)–P(1)–C(8) (–16.2°) and
C(6)–C(7)–P(1)–C(8) (167.3°) and an interplanar angle of
40.5° between the plane defined by the atoms N(1),N(2),
C(8) and P(1), C(7), C(8). From the X-ray structural data
it can be concluded that compound 2 is best described by
the zwitterionic limiting formula A and not by B or C
(Scheme 4).
Scheme 4. Canonical formulae for phosphaalkene 3.
Figure 2. Molecular crystal structure of 4a. Selected bond lengths
[Å] and angles [°]: Mo(1)–C(6) 1.974(2), Mo(1)–C(7) 1.971(2),
Mo(1)–P(1) 2.3754(4), Mo(1)–P(2) 2.5602(5), P(2)–C(20) 1.707(2),
C(20)–O(3) 1.402(2), C(20)–C(21) 1.472(2), P(1)–O(3) 1.666(1),
P(1)–C(8) 1.819(2), P(1)–C(14) 1.830(2); C(6)–Mo(1)–C(7) 78.8(1),
C(6)–Mo(1)–P(2) 72.9(1), C(7)–Mo(1)–P(1) 80.6(1), P(1)–Mo(1)–
P(2) 70.86(1), Mo(1)–P(1)–O(3) 112.51(4), P(1)–O(3)–C(20)
107.5(1), O(3)–C(20)–P(2) 121.7(1), Mo(1)–P(2)–C(20) 105.3(1),
O(3)–C(20)–C(21) 112.7(1), P(2)–C(20)–C(21) 125.3(1), Mo(1)–
C(6)–O(1) 177.9(2), Mo(1)–C(7)–O(2) 177.8(2)°.
Single crystals of 4a suitable for X-ray diffraction analysis
were grown from n-pentane at +4 °C. The analysis (Fig-
ure 2, Table 1) displays a molecule with a distorted four-
legged piano-stool geometry [C(6)–Mo(1)–C(7) 78.79(7)°,
C(6)–Mo(1)–P(2) 72.86(5)°, C(7)–Mo(1)–P(1) 80.57(5)°,
P(1)–Mo(1)–P(2) 70.86(1)°] with two nearly linear carbonyl
ligands [Mo(1)–C(6)–O(1) 177.9(2), Mo(1)–C(7)–O(2)
177.8(2)°]. The remaining two legs are represented by a
1,4,2-diphosphaoxabuten-3-yl ligand, which is chelating the
metal atom through bonds Mo(1)–P(1) [2.3754(4) Å] and
Repulsion between the lone pair of electrons at P(2) and
Mo(1)–P(2) [2.5602(5) Å]. The latter bond length compares the electron-rich Mo atom may be responsible for the in-
well to the Mo–P distance in the metallophosphaalkene creased bond length relative to the Mo(1)–P(1) distance.
[Cp(CO)3Mo–P=C(SiMe3)2] [2.568(1) Å].[10] The bond This novel chelating ligand features the double bond P(2)–
length between the metal atom and the tetracoordinated C(20) [1.707(2) Å], which compares well to the PC separa-
phosphorus atom of 2.3754(4) Å is slightly longer than the tion in the ferriophosphaalkene [Cp(CO)2Fe–P=C-
Mo–P contact in [Cp(CO)2Moa–PMe2–Cb(SiMe3)2(Moa–Cb)] (OSiMe3)tBu] [1.701(4) Å],[12] but it is markedly longer
[2.348(2) Å].[11]
than that in the molybdophosphaalkene [Cp(CO)3Mo–
Eur. J. Inorg. Chem. 2007, 4011–4016
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L. Weber, G. Noveski, S. Uthmann, H.-G. Stammler, B. Neumann
FULL PAPER
P=C(SiMe3)2] [1.665(3) Å]. The contact P(1)–O(3) bond formation then affords intermediate B. Finally, ring
[1.666(1) Å] is shorter than the sum of the covalent radii enlargement leads to the final products; however, interme-
(1.76 Å) but still reflects a bond order of unity.[13] Bond diates A and B were not detected by 31P NMR spectro-
C(20)–O(3), which in precursor 2 exists as a carbonyl group scopic monitoring of the reaction (Scheme 5).
with a bond length of 1.240(2) Å, is lengthened to a single
bond of length 1.402(2) Å. The metalloheterocycle is
slightly puckered (sum of endocyclic angles 517.9°).
Single crystals of 6b were grown from n-pentane/diethyl
ether at + 4 °C (Figure 3). Like 3a, this complex has the
geometry of a four-legged piano stool [C(6)–W(1)–C(7)
79.1(1), C(6)–W(1)–P(2) 72.9(1), C(7)–W(1)–C(7) 79.9(1),
P(1)–W(1)–P(2) 72.77(2)°]. A 1,4,2-diphosphaoxabuten-3-yl
ligand chelates the tungsten atom through bonds W(1)–P(1)
[2.3632(5) Å] and W(1)–P(2) [2.5556(5) Å]. The former
bond length is slightly shorter than the coordinative W–P
bond in 7 [2.432(2) Å][7] or 8 [2.434(2) Å].[14]
Scheme 5. Proposed mechanism for the synthesis of 4a,b and 6a,b.
Conclusions
Transition-metal-induced cleavage of inversely polarized
phosphaalkenes with concomitant transfer of the phos-
phanediyl unit on carbene- or phosphenium ligands to give
η1-phosphaalkene[2] and η2-diphosphanido complexes[5]
have previously been described. Here the smooth generation
of complexes 4a,b and 6a featuring the chelating 1,4,2-di-
phosphaoxabutene-3-yl ligand underlines the ability of
phosphaalkenes to act as convenient sources for phos-
phanediyl units under mild conditions.
Figure 3. Molecular crystal structure of 6b. Selected bond lengths
[Å] and angles [°]: W(1)–C(6) 1.980(2), W(1)–C(7) 1.966(2), W(1)–
P(1) 2.3632(5), W(1)–P(2) 2.5556(5), P(2)–C(20) 1.700(2), C(20)–
O(3) 1.402(2), C(20)–C(21) 1.468(2), P(1)–C(8) 1.824(2), P(1)–
C(14) 1.827(2); C(6)–W(1)–C(7) 79.1(1), C(6)–W(1)–P(2) 74.0(1),
C(6)–W(1)–P(1) 116.2(1), C(7)–W(1)–P(1) 79.9(1), C(7)–W(1)–P(2)
127.1(1), P(1)–W(1)–P(2) 72.77(2), W(1)–P(1)–O(3) 113.64(4),
P(1)–O(3)–C(20) 111.2(1), O(3)–C(20)–P(2) 121.7(1), W(1)–P(2)–
C(20) 105.3(1), O(3)–C(20)–C(21) 112.0(1), P(2)–C(20)–C(21)
126.1(1), W(1)–C(6)–O(1) 177.4(2), W(1)–C(7)–O(2) 178.8(2).
Experimental Section
General: All experiments were performed under a dry, oxygen-free
nitrogen atmosphere by using standard Schlenk techniques. Sol-
vents were carefully dried with an appropriate drying agent and
freshly distilled under an atmosphere of N2 before use. The follow-
ing compounds were prepared according to literature procedures:
[Cp(CO)2ClMo–PHPh2] (1a),[7] [Cp(CO)2ClW–PHPh2] (1b),[7]
PhC(O)P=C(NMe2)2 (3),[6] and Me3SiP=C(NMe2)2.[8] Diazabicy-
cloundecene (DBU), 4-EtC6H4C(O)Cl, and Florisil (0.150–
0.250 mm) were purchased commercially. IR spectra were recorded
Bonding parameters within the chelating ligand of 6b are
close to those in 4a and merit no particular discussion at
this point. The five-membered metalloheterocycle of 6b is
more flattened (sum of endocyclic angles 529.6°) relative to
that of 4a (517.9°).
with a Bruker FTIR VECTOR 22 spectrometer. 1H-, 13C-, and 31
P
NMR spectra were recorded at room temp. with a Bruker AM
Avance DRX 500 instrument. References: SiMe4 (1H, 13C) and
85% H3PO4 (31P). MS was conducted with a Bruker Esquire Ion
trap mass spectrometer autospec, sector field.
Mechanisms
It is conceivable that the path towards the formation of
complexes 4a, 4b, 6a, and 6b begins with nucleophilic attack
of phosphaalkenes 2,3 by its electron-abundant phosphorus
atom at the phosphenium center of 1a,b, which affords zwit-
4-EtC6H4C(O)P=C(NMe2)2 (5): A solution of Me3SiP=C(SiMe3)2
(0.25 g, 1.20 mmol) in n-pentane (20 mL) was added dropwise at
–30 °C to the solution of 4-EtC6H4C(O)Cl (0.20 g, 1.20 mmol) in
n-pentane(20 mL), whereby a yellow precipitate formed. Stirring
terion A. Release of a carbene unit and metal–phosphorus was continued at –30 °C for 1 h. The cold slurry was filtered, and
4014 Eur. J. Inorg. Chem. 2007, 4011–4016
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Phosphaalkenes: Reagents in 1,3-Dipolar Cycloaddition Reactions
FULL PAPER
the filtercake was washed with cold n-pentane (3ϫ20 mL, –30 °C).
The filtercake was dried at 10–3 bar to afford 5 as a bright yellow
powder (yield: 0.26 g, 81%). 1H NMR (500.13 MHz, C6D6): δ =
[M – CO]+. C26H20O3P2W (626.22): calcd. C 49.87, H 3.22; found
C 48.97, H 3.10.
[Cp(CO)2Moa–P=C(4-Et-C6H4)O–PbPh2(Moa–Pb)] (6a): As de-
scribed above, solutions of [Cp(CO)2ClMoPHPh2] (1a; 0.68 g,
1.55 mmol) in toluene (30 mL), 4-EtC6H4C(O)P=C(NMe2)2 (5;
0.41 g, 1.55 mmol), and DBU (0.36 g, 2.33 mmol) in toluene
(20 mL) were combined at –30 °C. Stirring was continued for 1 h
at –30 °C and 12 h at 20 °C. The solvent and the volatile compo-
nents were removed in vacuo, and the residue was chromato-
graphed on Florisil. A yellow zone was eluted with a pentane/di-
ethyl ether (10:3, ca. 350 mL). The elute was concentrated to ca.
50 mL and stored at –30 °C for 12 h. Product 6a separated as
orange crystals (yield: 0.32 g, 36%). 1H NMR (500.13 MHz,
3
3
0.99 (t, JHH = 7.5 Hz, 3 H, CH2CH3), 2.36 (q, JHH = 7.5 Hz, 2
H, CH2CH3), 2.59 (s, 12 H, NCH3), 7.05 (m, 2 H, m-H-Ph), 8.54
(m, 2 H, o-H-Ph) ppm. 13C{1H} NMR (125.75 MHz, C6D6): δ =
3
15.7 (s, CH2CH3), 29.0 (s, CH2CH3), 42.8 (d, JPC = 4.6 Hz,
2
NCH3), 126.9 (s, Ph), 127.0 (s, Ph), 142.9 (d, JPC = 48.3 Hz, i-C-
1
Ph), 147.1 (s, p-C-Ph), 200.2 (d, JPC = 78.2 Hz, P=C), 215.4 (d,
1JPC = 78.2 Hz, PC=O) ppm. 31P{1H} NMR (202.46 MHz, C6D6):
δ = 30.8 (s) ppm. IR (KBr): ν = 1535 [s (CO)] cm–1. MS (EI): m/z
˜
= 264 [M]+, 133 [4 – EtC6H4CO]+, 131 [P=C(NMe2)2]+, 105 [4 –
EtC6H4]+. C14H21N2OP (264.30): calcd. C 63.62, H 8.01, N 10.60;
found C 63.13, H 8.15, N 10.60.
3
3
C6D6): δ = 0.98 (t, JHH = 7.5 Hz, 3 H, CH2CH3), 2.31 (q, JHH
=
7.5 Hz, 2 H, CH2CH3), 4.59 (s, 5 H, Cp), 6.84 (m, 1 H, Ph), 6.89–
6.91 (m, 4 H, Ph), 7.05–7.11 (m, 4 H, Ph), 7.66 (m, 2 H, Ph), 7.84
(m, 2 H, Ph), 8.19 (m, 2 H, Ph) ppm. 13C{1H} NMR (125.75 MHz,
C6D6): δ = 15.6 (s, CH2CH3), 28.9 (s, CH2CH3), 93.0 (s, C5H5),
125.6, 125.8, 128.3, 128.4, 128.7, 128.8, 129.9, 130.1, 131.7, 132.5,
[Cp(CO)2Moa–P=C(Ph)O–PbPh2(Moa–Pb)] (4a): A solution of
[Cp(CO)2ClMoPHPh2] (1a; 0.80 g, 1.82 mmol) in toluene (40 mL)
was added dropwise to a chilled solution (–30 °C) of PhC(O)-
P=C(NMe2)2 (3; 1.29 g, 5.46 mmol) and DBU (0.42 g, 2.76 mmol)
in toluene (30 mL). After 2 h, the addition was complete, and stir-
ring at –30 °C was continued for 1 h. The mixture was then warmed
to room temp. and stirred overnight. Solvent and volatile compo-
nents were removed in vacuo. To the residue was added Florisil
(3 g) and toluene (15 mL), and the slurry was evaporated to dry-
ness. The remaining powder was brought on a column filled with
Florisil and pentane (l = 5 cm, d = 2 cm). First the column was
developed with pentane/diethyl ether (30:1) to separate a yellow
zone. This zone was eluted with pentane/diethyl ether (30:5, ca.
250 mL). Concentration of the elute to ca. 120 mL and storage for
12 h at –30 °C furnished product 4a as orange crystals (yield:
0.45 g, 46%). 1H NMR (500.13 MHz, C6D6): δ = 4.56 (s, 5 H, Cp),
6.80–7.08 (m, 9 H, Ph), 7.64 (m, 2 H, Ph), 7.81 (m, 2 H, Ph), 8.23
(m, 2 H, Ph) ppm. 13C{1H} NMR (125.75 MHz, C6D6): δ = 93.0
(s, C5H5), 125.4, 125.5, 127.9, 128.1, 128.3, 128.4, 128.5, 128.6,
128.7, 129.8, 129.9, 130.3, 131.7, 132.4, 132.5, 137.9 (s, Ph), 138.2
1
2
132.6 (s, Ph), 194.1 (dd, JPC = 86.2 Hz, JPC = 17.5 Hz, P=C),
234.3 (d, 2JPC = 12.1 Hz, CO), 241.5 (d, 2JPC = 25.6 Hz, CO) ppm.
2
31P{1H} NMR (202.46 MHz, C6D6): δ = 198.7 (d, JPP = 20.7 Hz,
2
PPh2), 225.9 (d, JPP = 20.7 Hz, P=C) ppm. IR (KBr): ν = 1942 [s
˜
(CO)], 1881 [s (CO)] cm–1. MS (EI): m/z = 568 [M]+, 540 [M –
CO]+, 512 [M – 2 CO]+. C28H24MoO3P2 (566.38): calcd. C 59.38,
H 4.27; found C 59.50, H 4.24.
[Cp(CO)2Wa–P=C(4-Et-C6H4)O–PbPh2(Wa–Pb)] (6b): As described
above, a solution of [Cp(CO)2ClWPHPh2] (1b; 0.91 g, 1.73 mmol)
in toluene (40 mL) was combined with a mixture of 4-EtC6H4C-
(O)P=C(NMe2)2 (5; 0.47 g, 1.78 mmol) and DBU (0.36 g,
2.33 mmol) in chilled toluene (20 mL, –10 °C). After stirring at
room temp. for 14 h, the mixture was evaporated to dryness, and
the residue was chromatographed on Florisil. A yellow zone was
eluted with pentane/diethyl ether (10:3, 250 mL; then 2:1, 200 mL).
The elute was concentrated to ca. 120 mL and stored at –30 °C for
24 h, whereby product 6b separated as yellow crystals (yield: 0.34 g,
1
2
(m, Ph), 141.7, 142.1 (s, Ph), 193.6 (dd, JPC = 85.6 Hz, JPC
=
=
2
2
17.8 Hz, P=C), 234.3 (d, JPC = 12.7 Hz, CO), 241.3 (d, JPC
1
3
30%). H NMR (500.13 MHz, C6D6): δ = 0.98 (t, JHH = 7.5 Hz,
26.4 Hz, CO) ppm. 31P{1H} NMR (202.46 MHz, C6D6): δ = 199.3
3
3 H, CH2CH3), 2.31 (q, JHH = 7.5 Hz, 2 H, CH2CH3), 4.58 (s, 5
2
2
(d, JPP = 21.8 Hz, PPh2), 235.5 (d, JPP = 21.8 Hz, P=C) ppm. IR
H, Cp), 6.83 (m, 1 H, Ph), 6.91 (m, 4 H, Ph), 7.03–7.11 (m, 3 H,
Ph), 7.68 (m, 2 H, Ph), 7.84 (m, 2 H, Ph), 8.23 (m, 2 H, Ph) ppm.
13C{1H} NMR (125.75 MHz, C6D6): δ = 15.6 (s, CH2CH3), 28.9
(s, CH2CH3), 91.6 (s, C5H5), 125.8, 125.9, 127.9, 128.3, 128.4,
128.6, 128.7, 130.1, 130.2, 130.4, 131.7, 132.9, 133.1, 135.7, 135.9,
136.0, 137.6, 138.0, 141.4, 141.8, 144.9, 145.0 (s, Ph), 193.4 (dd,
(KBr): ν = 1943 [s (CO)], 1874 [s (CO)] cm–1. MS (EI): m/z = 540
˜
[M]+, 484 [M – 2 CO]+. C26H20MoO3P2 (538.32): calcd. C 58.01,
H 3.74; found C 57.20, H 3.42.
[Cp(CO)2Wa–P=C(Ph)O–PbPh2(Wa–Pb)] (4b): A solution of [Cp-
(CO)2ClWPHPh2] (1b; 0.86 g, 1.63 mmol) in toluene (40 mL) was
added dropwise (2 h) to a cold solution (–10 °C) of PhC(O)-
P=C(NMe2)2 (3; 0.39 g, 1.63 mmol) and DBU (0.42 g, 2.76 mmol)
in toluene (20 mL). The mixture was warmed to ambient tempera-
ture and stirred for 12 h. Volatile components were removed in
vacuo, and the oily residue was combined with Florisil (2 g) and
toluene and then chromatographed on Florisil as described above.
A yellow zone was eluted with pentane/diethyl ether (3:2, ca.
300 mL). The elute was concentrated, and the residue was crys-
tallized from toluene/pentane (1:1, 20 mL) at –30 °C over 24 h. The
product separated as orange crystals (yield: 0.31 g, 31%). 1H NMR
2
1JPC = 82.8 Hz, JPC = 18.4 Hz, P=C), 223.9 (br., CO), 231.8 (d,
2JPC = 18.4 Hz, CO) ppm. 31P{1H} NMR (202.46 MHz, C6D6): δ
= 170.1 (d, JPP = 22.5 Hz, JPW = 330.4 Hz, PPh2), 199.9 (d, JPP
=
22.5 Hz, P=C) ppm. IR (KBr): ν = 1935 [s (CO)], 1870 [s (CO)]
˜
cm–1. MS (EI): m/z = 654 [M]+, 626 [M – CO]+, 598 [M – 2 CO]+.
C28H24O3P2W (654.28): calcd. C 51.40, H 3.69; found C 51.47, H
3.51.
X-ray Crystallography: Crystallographic data for 3 was collected
with a Siemens P3 diffractometer with Mo-Kα at 173 K, data for
4a and 6b were collected with a Nonius Kappa CCD diffractometer
(500.13 MHz, C6D6): δ = 4.55 (s, 5 H, Cp), 6.82 (m, 1 H, Ph), 6.89 with Mo-Kα (graphite monochromator, λ = 0.71073 Å) at 100 K.
(m, 2 H, Ph), 6.99–7.11 (m, 6 H, Ph), 7.64 (m, 2 H, Ph), 7.81 (m, 2,
Crystallographic programs used for the structure solution and re-
Ph), 8.24 (m, 2 H, Ph) ppm. 13C{1H} NMR (125.75 MHz, C6D6): δ
finement were from SHELX-97.[15] The structures were solved by
= 91.6 (s, C5H5), 125.6, 125.8, 130.0, 130.1, 130.4, 131.8, 132.9, direct methods and refined by using full-matrix least-squares on F2
1
2
133.0 (s, Ph), 192.9 (dd, JPC = 82.9 Hz, JPC = 18.2 Hz, P=C),
of all unique reflections with anisotropic thermal parameters for
223.9 (s, CO), 231.5 (d, JPC = 17.5 Hz, CO) ppm. 31P{1H} NMR all non-hydrogen atoms. Hydrogen atoms for 3 were refined iso-
2
(202.46 MHz, C6D6): δ = 170.7 (d, JPP = 21.8 Hz, 1JWP = 329.3 Hz, tropically, for 4a and 6b they were included at calculated positions
2
PPh2), 209.4 (d, JPP = 21.8 Hz, P=C) ppm. IR (KBr): ν = 1935 [s
with U(H) = 1.2 Ueq for CH2 groups, U(H) = 1.5 Ueq for CH3
˜
(CO)], 1864 [s (CO)] cm–1. MS (EI): m/z = 626 [M]+, 570
groups. Crystal data of the compounds are listed in Table 1.[16]
Eur. J. Inorg. Chem. 2007, 4011–4016
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
4015

L. Weber, G. Noveski, S. Uthmann, H.-G. Stammler, B. Neumann
FULL PAPER
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[15] G. M. Sheldrick, SHELX-97: Programs for Solution and Re-
finement of Crystal Structures, University of Göttingen, Ger-
many, 1997.
[16] CCDC-141724, -644445, and -644446 contain the supplemen-
tary 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.
Received: April 23, 2007
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Published Online: July 4, 2007
4016
www.eurjic.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2007, 4011–4016