Reactions of protic reagents with a tungsten phosphenium ion complex

Article abstract of DOI:10.1016/S0022-328X(98)00649-4

The reactions of metallophosphenium ion complex CpW(CO)₂{P(Ph)[N(SiMe₃)₂]} with protic reagents HBF₄, HCl, and CF₃COOH have been studied. The 1:1 reactions result in protonation of the W=P bond, while the 1:2 reactions display cleavage of the P-N bond. The molecular structure of one product, Cp(CO)₂(Cl)WP(H)(Ph)[N(SiMe₃)₂], was determined by single crystal X-ray diffraction techniques: triclinic space group P1 with a=9.6732(14) A, b=11.3419(15) A, c=11.5930(14) A, α=87.724(11)°, β=77.647(11)°, γ=82.989(11)°, V=1233.0(3) A³, Z=2.

Full text of DOI:10.1016/S0022-328X(98)00649-4

Journal of Organometallic Chemistry 564 (1998) 13–20
Reactions of protic reagents with a tungsten phosphenium ion complex
Hans-Ulrich Reisacher, Eileen N. Duesler, Robert T. Paine *
Department of Chemistry, Uni6ersity of New Mexico, , Albuquerque, NM, USA
Received 2 December 1997; received in revised form 26 March 1998
Abstract
The reactions of metallophosphenium ion complex CpW(CO)2{P(Ph)[N(SiMe3)2]} with protic reagents HBF4, HCl, and
CF3COOH have been studied. The 1:1 reactions result in protonation of the WꢀP bond, while the 1:2 reactions display cleavage
of the P–N bond. The molecular structure of one product, Cp(CO)2(Cl)WP(H)(Ph)[N(SiMe3)2], was determined by single crystal
˚
˚
˚
(
X-ray diffraction techniques: triclinic space group P1 with a=9.6732(14) A, b=11.3419(15) A, c=11.5930(14) A, h=
3
˚
87.724(11)°, i=77.647(11)°, k=82.989(11)°, V=1233.0(3) A , Z=2. © 1998 Elsevier Science S.A. All rights reserved.
Keywords: Tungsten; Phosphorus; Phosphenium ion; Acid reactivity
atom when combined with CF3SO3H, CF3SO3CH3, and
S8, respectively ([2]f). Unlike 1, the phosphorus lone
1. Introduction
pair in 2 is involved in MꢀP multiple bonding; therefore
it is expected that the P atom reactivity might be
somewhat d¸if¹fe¹re¹n¹t.¹M¹a¹l¹iscºh ([2]c) reported that 2, e.g.
CpM(CO)2[POCMe2CMe2O] (M=Cr, Mo, W) ([2]d),
and CpMo[P(NMe2)2]) ([2]a), react with S8 to give
thio-bridged species 3a (E=S). Reaction of CH2N2
with the former compound produces a [2+1] cycload-
dition species 3b (E=CH2), and addition of Fe2(CO)9
results in 3c (E=Fe(CO)4). Malisch et al. ([2]c) have
also reported that CpW(CO)2[P(tBu)2] reacts with S8,
Se, CH2N2, (MeP)5, Me2P, Fe2(CO)9, and Ru3(CO)10,
each forming [2+1] cycloaddition products 3. With
M=Mo, and W and X=Y=alkyl and aryl, it was
reported that alkenes, alkynes, and dienes give [2+2]
and [2+4] cycloadditions and metal halides CuCl,
AgCl, Au(Cl)PPh3, and Rh(CO)2Cl produce [2+1] cy-
cloadditions ([2]c). Lang and associates ([3]b,f) have
recently reported reactivity studies on bifunctional |3,
u4-phosphanediyl phosphenium complexes CpM(CO)2
[P(R)CꢁCR], CpM(CO)2[P(R)C(H)ꢀC(H)R], and CpM
(CO)2[P(R)CH2CꢁCH], and these species also undergo
[2+1] cycloadditions with CH2N2, Fe(CO)5, PhN3, and
(2,4,6-Me3C6H2)N3.
Some
metal
carbonyl
anions
react
with
monochlorophosphanes of the general type (X)(Y)PCl
to initially give metallophosphane complexes 1 contain-
ing a terminal, pyramidal P(X)(Y) fragment. Many of
these compounds undergo intramolecular CO displace-
ment reactions that produce metallophosphenium ion
complexes 2 which possess a planar MP(X)(Y) frag-
ment, and short MꢀP bond. This process is summarized
in Scheme 1 specifically for metal carbonyl fragments
CpM(CO)3− (M=Cr, Mo, W) [1–4].
The reactivity of 1 and 2 is of interest as a probe of
the electronic properties of these molecules. For exam-
ple, additions of H3B·THF, CH3I, and Ni(CO)4 to 1,
e.g. CpW(CO)2(Me3P)(Ph2P), produce phosphane ad-
ducts CpW(CO)2(Me3P)[P(A)(Ph)2] (A=H3B,CH3+,
Ni(CO)3), and oxidations with S8, and Br2 occur at the
phosphorus atom ([2]d). Similarly, the metallophos-
phaalkene CpW(CO)3[P=C(SiMe3)2] undergoes proto-
nation, methylation, and oxidation at the phosphorus
* Corresponding author. Tel.: +1 505 2776655; fax: +1 505
2772609.
0022-328X/98/$19.00 © 1998 Elsevier Science S.A. All rights reserved.
PII S0022-328X(98)00649-4

14
H.-U. Reisacher et al. / Journal of Organometallic Chemistry 564 (1998) 13–20
2. Experimental
It is apparent from these results that the reactivity of
1 is dominated by the phosphorus lone pair nucle-
ophilicity, while the reactivity in 2 seems centered on
the electron rich MꢀP bond. Still, it appears that the P
atom in 2 retains a good deal of nucleophilic character.
For example, we observe that H3B·THF adds across
the MꢀP double bond in CpMo(CO)2{P(Ph)[N
(SiMe3)2]} 4a giving the complex 5, whose unique struc-
ture was deduced by single crystal X-ray diffraction
analysis ([4]f). Identical chemistry occurs with Cp-
W(CO)2{P(Ph)[N(SiMe3)2]} 4b [5]. Reactions with other
classical Lewis acids, e.g. BCl3, BBr3, BH2Cl and AlCl3,
have been studied; however, pure products are not
obtained [6]. Compound 4a also reacts with Fe2(CO)9
to give 6. This compound is of the general type illus-
trated by 3 (EꢀFe(CO)4, X=Ph, Y=N(SiMe3)2) ([4]h);
however, single crystal X-ray diffraction analysis shows
that the molecular structure does not feature a three-
membered ring core, but instead displays a bridging CO
interaction between the Mo and Fe centers.
Standard inert atmosphere techniques were employed
for the synthesis and manipulation of all compounds.
Solvents were dried, deoxygenated, and distilled prior
to use. Mass spectra were obtained by using a Finnegan
GC/MS spectrometer and samples were introduced via
the solids probe. IR spectra were measured on a Nicolet
model 6000 FT-IR spectrometer by using solution cells.
NMR spectra were recorded on Varian FT-80A and
GE NT-360 spectrometers. Spectral standards were
Me4Si (13C, 1H) and H3PO4 (31P). Downfield shifts from
the standard were given a positive sign. The complex
CpW(CO)2{P(Ph)[N(SiMe3)2] 4b ([4]i) was prepared
from NaWCp(CO)3 [7] and Ph(Cl)P[N(SiMe3)2] [8].
Samples of the acids were obtained from Aldrich
Chemical Co. Microanalyses were obtained from the
UNM microanalytical facility.
2.1. Reaction of Cp(CO)2W{P(Ph)[N(SiMe3)2]} with
HCl; 1:1 ratio
To 1.0 g (1.75 mmol) of 4b in 30 ml of THF held at
−78°C was added 0.3 ml (2.0 mmol) of a HCl solution
(pre-titrated) in Et2O. The mixture was stirred for 1 h
and then warmed to 23°C and stirred for 1 h. The
purple color of 4b changed rapidly to red upon warm-
ing. The volatiles were vacuum evaporated, the residue
dissolved in benzene, filtered and the filtrate evapo-
rated. The red residue was recrystallized from cold
benzene, leaving red crystals of 7: yield 0.87 g, 82%;
m.p.: 196–198°C. Anal. Calc. for C19H29NO2PSi2ClW:
C, 37.42; H, 4.79; N, 2.30. Found: C, 35.80; H, 4.88; N,
2.41. Mass spectrum (m/e, relative intensity): 613–607
(M+, 1.5%), 585–579 (M–CO+, 3.5%), 576–572 (M–
Cl+, 45%), 557–553 (M–2CO+, 10%). IR spectrum
We have also recently reported on the outcome of
oxidations of 4a and 4b with S8 and Se ([4]i), and here
we report reactions with protic sources HBF4, HCl, and
CF3COOH.
(cyclohexane, cm−1) (carbonyl region): 1928, 1859.
1
31P{1H}-NMR (C6D6): l 27.0 (1JPW=308 Hz, JPH
=
408 Hz). 1H-NMR (C6D6): l 8.0–7.2 (m, Ph), 7.39
(1JPH=410 Hz), 5.48 (Cp), 0.26 (SiMe3). 13C{1H}-
1
NMR (C6D6): l 135.3 (d, JCP=32 Hz, Ph (C1)), 133.0
(Ph(C6)), 132.9 (Ph (C3,5), 130.5 (Ph, C2,4), 92.7 (Cp),
3.1 (SiMe3).
2.2. Reaction of Cp(CO)2W{P(Ph)[N(SiMe3)2]} with
excess HCl
To 1.0 g (1.75 mmol) of 4b in 30 ml of benzene was
added 0.9 ml (9.0 mmol) of an HCl solution (pre-ti-
trated) in Et2O. The mixture was heated to 50°C and
the solution color changed from purple to orange. After
stirring at 50°C for 30 min, the mixture was cooled to
23°C, filtered and solvent evaporated to dryness leaving
an orange solid 8: yield 0.51g, 60%. IR spectrum (cyclo-
hexane, cm−1) (carbonyl region): 1963 and 1884.
1
Scheme 1.
31P{1H}-NMR (C6D6): l 41.7 (1JPW=313 Hz, JPH
=

H.-U. Reisacher et al. / Journal of Organometallic Chemistry 564 (1998) 13–20
15
1
421 Hz). H-NMR (C6D6): l 8.0–7.6 (Ph), 5.18 (Cp).
13C{1H}-NMR (C6D6):
135.2 (Ph(C1)), 133.2
which time the color changed to red–brown and a
small amount of brown solid formed. The solution was
filtered and the filtrate evaporated leaving a red–
brown solid 10, which was washed with two 10 ml
portions of cyclohexane: yield 0.69 g (61%); m.p.: 115–
118°C. Anal. Calc. For C21H29NO4F3Si2PW: C,
36.69; H, 4.25; N, 2.04. Found: C, 38.14; H, 4.44; N,
1.86. IR spectrum (benzene, cm−1): 1930, 1852,
1721. 31P{1H}-NMR (C6D6): l 35.6 (1JPW=379 Hz,
l
(Ph(C6)), 132.7 (Ph (C3,5)), 129.9 (Ph(C2,4)), 93.2 (Cp).
2.3. Reaction of Cp(CO)2W{P(Ph)[N(SiMe3)2]} with
HBF4; 1:1 ratio
To 1.0 g (1.75 mmol) of 4b in 20 ml of toluene held
at −78°C was added 0.29
g (1.79 mmol) of
1
1
HBF4 ·OEt2. The mixture was stirred and warmed to
23°C, during which time the solution color changed to
red–brown and a brown solid formed. The mixture was
filtered and the filtrate evaporated, producing a larger
quantity of brown solid (9a): yield 0.74 g (64%); m.p.:
148–150°C (dec.). Anal. Calc. For C19H29BNO2
F4Si2PW: C, 34.51; H, 4.42; N, 2.12. Found: C, 34.95;
H, 4.51; N, 2.11. IR spectrum (benzene, cm−1): 1971,
1JPH=339 Hz), 29.2 (1JPW=331, JPH=372 Hz). H-
NMR (C6D6): l 8.17 (1JPH=360 Hz), 8.02 (1JPH=382
Hz), 7.8–7.4 (Ph), 5.18 (Cp), 5.10 (Cp), 0.27
(SiMe3).
2.6. Structure determination
Suitable crystals of 7 were obtained by slow crystal-
lization from saturated benzene solution. A crystal was
placed in a glass capillary under nitrogen and sealed.
The crystal was centered on a Siemens R3m/V four
circle diffractometer, and determinations of the crystal
class, orientation matrix, and accurate unit cell parame-
ters were made at 20°C. The crystal parameters and
data collection parameters are summarized in Table 1.
The intensity data were collected with Mo–Kh (u=
1872. 31P{1H}-NMR (C6D6): l 205.9 (1JPW=361 Hz,
1
J
PH=76 Hz), 178.2 (1JPW=390 Hz, JPH=76 Hz). H-
NMR (C6D6): l 7.8–7.1 (Ph), 5.29 (Cp) 4.97 (Cp), 0.35
(SiMe3), 0.33 (SiMe3), 0.27 (SiMe3).
Attempts were made to recrystallize 9a from several
solvents. During the course of these attempts, crystals
of 9b deposited from Et2O/toluene solutions held at
−30°C. Mass spectrum (m/e, relative intensity): 669–
662 (M+, 30%), 642–635 (M–CO+, 20%), 614–605
(M–2CO+, 40%), 586–577 (40%), 558–549 (30%),
530–521 (20%). IR spectrum (cyclohexane, cm−1):
1945, 1864. 31P{1H}-NMR (C6D6): l 27.6 (1JPW=307
˚
0.71069 A) monochromated radiation, a scintillation
counter, and pulse height analyzer. Intensities of three
standard reflections were measured at the beginning
and end of each ꢀ scan. No crystal decay was noted.
All calculations were performed on the Siemens P3
structure solution system using SHELXTL. Neutral
atom scattering factors and anomalous dispersion terms
were used for all non-hydrogen atoms during the refin-
ements. A small empirical adsorption correction was
applied based upon C scans. The structure was solved
by standard heavy atom methods. Full matrix least
squares methods were utilized in the refinements and
the function minimized was ꢀꢀ(ꢁFoꢁꢂꢁFcꢁ)2. Table 2 con-
tains a listing of the atom positional parameters, and
selected bond distances and angles are summarized in
Table 3.
1
Hz, JPH=392 Hz).
2.4. Reaction of 9a with Ph3P
A sample of 9a (0.5 g, 0.8 mmol) was combined with
Ph3P (0.21 g, 0.8 mmol) in benzene and stirred at 23°C
for 2 h. The solvent was evaporated and the residue
recrystallized from benzene leaving a reddish solid 9c:
yield 0.6 g (65%); m.p.: 94–96°C. Anal. Calc. for
C37H45BO2NF4Si2P2W: C, 48.07; H, 4.91; N, 1.52.
Found: C, 49.04; H, 5.18; N, 1.39. Mass spectrum (m/e,
relative intensity): 855–845 (M–SiMe3+, 0.1%), 776–
767 (M–Ph–SiMe3H+, 0.2%), 745–739 (M–Ph–
SiMe3H–CO, 0.1%), 715–709 (M–Ph–SiMe3H–
2CO+, 0.1%), 639–631 (M–PPh3–CO, 0.3%), 610–601
(M–PPh3–2CO, 1%). IR spectrum (cyclohexane, cm−
1): 1969, 1932, 1885. 31P{1H}-NMR (C6D6): l 22.5
(1JPH=410 Hz), 20.3 (2JPP=12 Hz). 13C{1H}-NMR
(C6D6): l 7.7–7.1 (Ph), 7.6 (1JPH=395 Hz), 5.50 (Cp),
0.26 (SiMe3).
3. Results and discussion
The reactions of protic reagents with metallopho-
sphenium and metallophosphane complexes appear to
have been little studied. Malisch and coworkers ([4]b)
reported that reactions of Cp(CO)2WP(tBu)2 with H2O,
MeOH and EtOH produce addition across the formal
WꢀP bond, giving Cp(CO)2(H)W[P(X)tBu2] X=OH,
MeO and EtO. Spectroscopic characterization data
were provided only for the product having X=OH.
Cowley and coworkers ([1]e) reported that the phos-
phavinylidene complex Cp(CO)2Mo [PꢀC(SiMe3)2]
2.5. Reaction of Cp(CO)2W{P(Ph)[N(SiMe3)2]} with
CF3COOH; 1:1 ratio
To 1.0 g (1.75 mmol) of 4b in 20 ml of THF was
added 0.20 g (1.75 mmol) of CF3COOH at −78°C.
The mixture was stirred and warmed over 2 h, during
i
combines with EtOH, CD3OH, Pr2NH and C6F5SH to

16
H.-U. Reisacher et al. / Journal of Organometallic Chemistry 564 (1998) 13–20
Table 2
give Cp(CO)2MoP(H)[C(X)(SiMe3)2] X=EtO, CD3O,
iPr2N and C6F5S. The phosphaalkene, Cp(CO)3WPꢀC
(SiMe3)2, on the other hand, reacts with CF3SO3H to
give Cp(CO)3W[P(H)C(SiMe3)2]+(F3CSO3−). The last
reaction, of course, can be considered a protonation of
the lone pair on the ‘bent’ phosphaalkene phosphorus
atom.
Atomic positional parameters for CpW(CO)2Cl{P(H)(Ph)[N(SiMe3)2]
7
Atom
x/a
0.18654(3)
y/b
z/c
0.08439(2)
W
Cl
0.22263(2)
0.35260(13)
0.1022(5)
0.0256(4)
0.1015(5)
0.0263(4)
0.3267(5)
0.3288(5)
0.2094(5)
0.1354(6)
0.2087(5)
0.33836(11)
0.2900(3)
0.2397(2)
0.1815(7)
0.3627(6)
0.1219(7)
0.2941(1)
0.3924(7)
0.1477(6)
0.3566(7)
0.5001(4)
0.5606(4)
0.6836(5)
0.7435(5)
0.6833(5)
0.5625(4)
−0.04374(15)
0.2944(7)
0.3560(6)
0.0594(7)
−0.0127(5)
0.1948(7)
0.3243(7)
0.3843(7)
0.2917(7)
0.1695(8)
0.21442(15)
0.3314(4)
0.2517(2)
0.3969(9)
0.1429(7)
0.1393(11)
0.5160(2)
0.5874(7)
0.6185(8)
0.5523(7)
0.2211(5)
0.1886(6)
0.1901(6)
0.2259(7)
0.2580(7)
0.2572(6)
0.14684(14)
0.1643(6)
0.2091(5)
0.1385(6)
0.1682(6)
−0.0999(5)
−0.0723(5)
−0.0659(5)
−0.0917(6)
−0.1111(5)
0.25668(12)
0.3435(4)
0.4867(2)
0.5680(7)
0.5759(5)
0.4776(7)
0.2931(2)
0.3814(7)
0.2862(8)
0.1422(6)
0.2395(5)
0.1416(5)
0.1312(6)
0.2182(7)
0.3162(7)
0.3261(5)
C(1)
O(1)
C(2)
O(2)
C(9)
C(10)
C(11)
C(12)
C(13)
P
In the present study, we have examined the reactions
of the metallophosphenium complex Cp(CO)2W[P(Ph)
[N(SiMe3)2] 4b with the proton donors HCl·OEt2,
HBF4 ·OEt2, and CF3COOH. The reactions are sensi-
tive to reagent stoichiometry and solvent. The 1:1 reac-
tion of 4b and HCl·OEt2 in THF solution leads to
isolation of Cp(CO)2W(Cl){P(H)(Ph)[N(SiMe3)2]} 7 in
high yield as a red crystalline solid. NMR tube reac-
tions of 7 with equimolar amounts of the proton accep-
N
Si(1)
C(14)
C(15)
C(16)
Si(2)
C(17)
C(18)
C(19)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
t
tors BuLi or DBU result in reversal of the protonation
process and quantitative reformation of 4b as indicated
by its 31P chemical shift. Compound 7 is also obtained
in an NMR tube scale reaction from the combination
of Cp(CO)3WCl and P(H)(Ph)[N(SiMe3)2] in benzene at
60°C. This chemistry is summarized in Scheme 2.
The mass spectrum of compound 7 displays a parent
ion envelope m/e 613–607, and fragment ion envelopes
corresponding to [M–CO+], [M–Cl+] and [M–2CO+].
The compound shows two IR bands in the terminal CO
stretch region at 1928 and 1859 cm−1, both shifted
slightly down frequency from the frequencies of 4b:
1941 and 1869 cm−1 [6]. The 31P{1H}-NMR spectrum
shows a resonance centered at l 27.0 with 183W–31P
coupling, 1JPW=308 Hz. The 1H-coupled 31P-NMR
spectrum displays a doublet with 1JPH=408 Hz. As
expected, the chemical shift and JPW are predictably
Table 1
1
Summary
of
X-ray
diffraction
data
for
Cp-
1
different from the values in 4b: l 267; JPW=702 Hz.
W(CO)2Cl{P(H)(Ph)[N(SiMe3)2]} 7
The 1H-NMR spectrum contains a complex multiplet, l
8.0–7.2, a singlet, l 5.48, and a singlet, l 0.26, that may
be assigned to the Ph, Cp and N(SiMe3)2 groups,
respectively. These data are comparable to data for 4b:
Formula
C19H28O2Si2PClW
0.18×0.21×0.29
Triclinic
Crystal dimensions (mm)
Crystal system
Space group
(
P1 (no. 2)
˚
a, A
9.6732(14)
11.3419(15)
11.5930(16)
87.724(11)
77.647(11)
82.989(11)
1233.0(3)
2
˚
b, A
Table 3
˚
c, A
Selected geometric data for CpW(CO)2Cl{P(H)(Ph)[N(SiMe3)2] 7
h, °
i, °
k, °
˚
Distances (A)
W–Cl
W–P
W–C(1)
W–C(2)
W–C(Cp)avg
2.501(1)
2.513(1)
1.942(6)
1.952(6)
2.334
C(1)–O(1)
C(2)–O(2)
P–N
P–C(3)
N–Si(1)
N–Si(2)
1.162(8)
1.161(8)
1.699(5)
1.846(5)
1.779(4)
1.762(4)
3
˚
V, A
Z
Formula weight
608.95
1.64
52.2
598
Dcalc. (g cm−3
)
Absorption coefficient (mm−1
F(000)
)
Temperature (K)
2q limit
293
2–55°
12.321
4851 (F\3|(F))
4.84
Angles (°)
C(1)–W–C(2)
Cl–W–C(1)
Cl–W–C(2)
Cl–W–P
C(1)–W–P
C(2)–W–P
74.6(3)
134.0(2)
80.2(2)
74.1(1)
79.4(2)
110.2(2)
W–C(1)–O(1)
W–C(2)–O(2)
W–P–N
W–P–C(3)
N–P–C(3)
P–N–Si(1)
P–N–Si(2)
Si(1)–N–Si(2)
176.3(6)
177.4(5)
122.8(1)
119.0(2)
105.4(2)
114.6(2)
121.3(2)
124.0(3)
No. collected reflections
No. observed reflections
R (%)a
Rw (%)b
3.37
NO, number of observations; NV, number of variables.
1
2
a R=ꢀ(ꢁFoꢁꢂꢁFcꢁ)/ꢀꢁFoꢁ; Rw={ꢀw(ꢁFoꢁꢂꢁFcꢁ)2/ꢀwꢁFoꢁ } .
2
1
b GOF, [w(ꢁFoꢁꢂꢁFcꢁ)2/(NOꢂNV)]2.

H.-U. Reisacher et al. / Journal of Organometallic Chemistry 564 (1998) 13–20
17
Scheme 2.
Fig. 2. Newman projection down the W–P bond vector for 7.
7.8–7.3, 5.73, 0.37. In addition, 7 displays a doublet
centered at l 7.39 with JPH ca. 410 Hz which is assigned
to the terminal P–H group. These spectroscopic data
are clearly consistent with addition of the HCl molecule
across the WꢀP bond, and the large value of the P–H
coupling constant is indicative of proton addition to the
P atom as opposed to the W atom.
˚
1.949(3), 1.151(5) A and 81.7(1)°, which have been
refined more accurately ([4]i). The average value of the
W–C(Cp) distances, 2.334AAA, is similar to the aver-
˚
age values of M–C distances in 4a, 2.348 A, and 4b,
˚
2.39 A.
The chiral phosphorus atom is bonded to the W
atom, the H atom, the phenyl ring and the (Me3Si)2N
group, and it has a distorted tetrahedral geometry. The
molecular structure and a view of the arrangement of
substituents relative to the CpW(CO)2Cl fragment are
shown in Figs. 1 and 2, respectively. The W–P bond
length, 2.513(1) A, is significantly longer than the W–P
distance in 4b, 2.252(6) A [6], and the Mo–P distance in
The proposed molecular structure of 7 is confirmed
by the results of single crystal X-ray diffraction analy-
sis. The compound has a four-legged piano stool struc-
ture formed by the Cp ring, two CO ligands, the
phosphorus atom, and the Cl atom bonded to the
central W atom. The CO ligands are in cis positions.
There is no evidence in the solid state or in solution for
˚
˚
˚
4a, 2.248(1) A. This distance and the geometry about
˚
the trans isomer. The average W–CO, 1.947 A and
the P atom are consistent with disruption of the WꢀP
multiple bonding and modification of the P atom hy-
bridization from sp2 to sp3. The P–N bond distance,
˚
CꢁO, 1.162 A bond lengths, and OC–W–CO bond
angle, 74.6(3)°, are similar to values displayed by 4b,
˚
1.94 , 1.27 A and 78(2)°, although the parameters for 4b
˚
1.699(5) A is similar to the distances in 4a and 4b.
are less reliable due to a disorder problem in the phenyl
group bound to the P atom [6]. The data are also
comparable to parameters for the Mo compound 4a:
The 1:2 reaction of 4b and HCl in benzene/Et2O
solution at 50°C results in the formation of an orange
solid 8, which was not obtained in analytically pure
form. An IR spectrum shows two bands in the wCO
region at 1963 and 1884 cm−1 that are upfrequency
from the bands for 4b or 7. The 31P{1H}-NMR spec-
trum shows a single peak at l 41.7, which is downfield
from 7 but still significantly upfield of 4b. This reso-
1
nance displays W–P coupling, JPW=313 Hz, and the
proton coupled spectrum shows a doublet structure
with JPH=421 Hz. The H and 13C{1H}-NMR spectra
are also informative, as neither shows the presence of
the (Me3Si)2N group. Based upon this data it is pro-
posed that the first equivalent of HCl produces 7,
which, with additional HCl, undergoes reaction at the
P–N bond, resulting in cleavage and formation of a
Cl–P bond and (Me3Si)2N(H)2Cl. This is a common
reaction of aminophosphanes [9]. Unfortunately, since
the phosphane Ph(Cl)PH is unavailable, 8 was not
independently prepared from base displacement on
CpW(CO)3Cl.
1
1
Fig. 1. Molecular structure and atom labeling scheme for Cp-
W(CO)2Cl{P(H)(Ph)[N(SiMe3)2] 7. Thermal ellipsoids shown at 30%.

18
H.-U. Reisacher et al. / Journal of Organometallic Chemistry 564 (1998) 13–20
Scheme 3.
the formation of cis and trans isomers of 9a with a
four-legged piano stool structure. The H-NMR spec-
The reaction of 4b with HBF4 ·OEt2 in a 1:1 ratio in
1
toluene appears to take a different course, as summa-
rized in Scheme 3. Initially at 23°C a brown solid is
formed whose CHN analysis is consistent with the
suggested composition of 9a. Reaction of this com-
pound in an NMR tube with DBU regenerates 4b.
Compound 9a does not show a parent ion in the
EI-mass spectrum, but it does show weak fragment
envelopes corresponding to [4b+] (m/e 575–571) and
[4b+HF+], (m/e 595–591).]. The IR spectrum ob-
tained from benzene solution shows two strong bands
in the wCO region at 1971 and 1872 cm−1, as well as a
band at 1946 cm−1. The last band is likely to belong to
unreacted 4b, whose second wCO band at 1869 cm−1 is
obscured by the 1872 cm−1 band of 9a. The 31P{1H}-
NMR spectrum shows two resonances of nearly equal
intensity centered at l 205.9 and 178.2, and both dis-
play 183W–31P satellites, 1JPW=361 Hz and 390 Hz,
respectively. These coupling constants fall in the upper
end of the range associated with phosphane metal
complexes, and they are consistent with sp3 hybridiza-
tion for the P atom in 9a. The proton coupled 31P-
NMR spectrum shows both of these resonances split
into a doublet with JPH=76 Hz. The small value
suggests that it does not originate from one bond
coupling but instead from two bond coupling, as would
occur in the proposed structure. The presence of two
peaks in the 31P{1H}-NMR spectrum is consistent with
trum in fact shows two Cp resonances, l 5.29 and 4.97,
of equal intensity, and three Me3Si resonances, l 0.35,
0.33 and 0.27 with 1:1:2 ratios. The integrated intensi-
ties of all five peaks are 5:5:9:9:18. Unfortunately, a
resonance that could be unambiguously assigned to a
proton bound to W is not detected.
During attempts to recrystallize 9a, a red microcrys-
talline compound 9b was obtained in modest yield. The
compound displays a different, more intense mass spec-
trum than 9a. The highest mass envelope at m/e 669–
662 corresponds to the ion (M–BF3−), and envelopes
corresponding to (M–BF3–CO+) and (M–BF3–
2CO+) are also observed. The IR spectrum contains
two wCO bands at 1945 and 1864 cm−1, which are
essentially unshifted from bands in 4b. The 31P{1H}-
NMR spectrum shows a single resonance at l 27.6 with
1JPW=307 Hz. The proton coupled 31P-NMR spectrum
contains a doublet with JPH=392 Hz. This value is
fully consistent with one-bond P–H coupling. These
data suggest that, in the presence of Et2O from the
reaction medium, 9a rearranges by coordination of
Et2O at the W atom and transfer of the H atom from
the W atom to the P atom. Similarly, addition of Ph3P
or Me3P to fresh solutions of 9a in benzene gives 9c and
9d, respectively. Compound 9c does not display a par-
ent ion in the mass spectrum, but fragment ion en-

H.-U. Reisacher et al. / Journal of Organometallic Chemistry 564 (1998) 13–20
19
velopes for (M–SiMe3+) as well as (M–PPh3–CO+)
and (M–PPh3–2CO+) are observed. The IR spectrum
shows three bands in the wCO region at 1969, 1932 and
1885 cm−1. One of the first two may be due to an
impurity, as the NMR spectra show no evidence for
isomers. The 31P{1H}-NMR spectrum for 9c displays
two doublet resonances of equal intensity at l 22.5 and
4. Conclusion
The reactions of the proton donors HCl,
HBF4 ·OEt2, and CF3COOH with the metallophosphe-
nium ion complex 4b reveal additional interesting fea-
tures about the nature of the WꢀP bond. Most
importantly, there appears to exist a delicate balance
between the acceptor properties of the CpW(CO)2 frag-
ment and H+ toward the lone pair of electrons on the
phosphenium ion fragment in 4b. With proton donors
(e.g. HCl and CF3COOH) that provide a basic, coordi-
nating anion, protonation occurs at the phosphorus
atom and the anion binds to the tungsten atom, thereby
accommodating for some of the loss of | electron
density from the phosphorus lone pair. For proton
donors that do not provide a strongly coordinating
anion, e.g. BF4−, protonation appears to take place
initially at the tungsten atom, suggesting that the
HOMO in 4b may reside in a metal centered orbital.
However, if a secondary neutral base is provided, e.g.
Et2O, Ph3P, Me3P, the proton migrates to the P atom
and the neutral base coordinates to the W atom. These
interesting results should stimulate further reactivity
studies of this electronically interesting class of metal
complexes.
2
20.3 with JPP=12 Hz. Neither resonance reveals P–W
satellite coupling, although the low solubility of the
compound limits the signal-to-noise achieved in the
spectrum. The proton coupled spectrum shows the
downfield doublet split into a doublet of doublets with
1JPH=410 Hz.
The synthesis of 9d was followed only through NMR
analysis. In this case the 31P{1H}-NMR data clearly
indicate the formation of two isomers with isomer
1/isomer 2=3/1. The following 31P-NMR data were
2
obtained: isomer 1, lA 21.6, lB −18.9, J% =15.8 Hz,
PP
1JPW=180 Hz, and isomer 2, lA 20.05, lB −19.47,
2J% =23.1 Hz, 1JPW=240 Hz. These coupling constant
PP
values are similar to those reported for Cp-
W(CO)2(PMe3)[P(H)(Mes)] ([4]h).
The 1:2 reaction of 4b with HBF4 ·OEt2 in THF or
benzene produced a complex mixture which appears to
include a bimetallic product (based upon M.S. analy-
sis); however, full characterization was hampered by
separation and purification problems.
5. Supplementary material available
The 1:1 reaction of 4b with CF3COOH in THF
solution was also studied. The resulting red–brown
solid 10 (Eq. 1) was not obtained in analytically pure
form. Nonetheless, the following data were obtained.
The IR spectrum from benzene solution shows three
bands in the carbonyl region: 1930, 1852 and 1721
cm−1. The first two bands can be assigned to terminal
wCO stretches, while the last, most likely, is a carboxy-
late band. The 31P{1H}-NMR spectrum consists of two
resonances centered at l 35.6, 1JPW=339 Hz and l
Tables of crystal structure analysis data, atomic coor-
dinates, anisotropic thermal parameters, H-atom coor-
dinates, and full listings of bond distances and angles
(13 pages) and calculated and observed structure fac-
tors (16 pages) for 7. Ordering information is given on
any current masthead page.
Acknowledgements
1
29.2, JPW=331 Hz with ca. 1:1 area ratios. These are
considered to result from cis and trans isomers of 10. In
the proton coupled spectrum each resonance is split
into a doublet with 1JPH=379 and 372 Hz, respectively.
Consistent with this model, the 1H-NMR spectrum
shows two Cp resonances, l 5.18 and 5.10, and two
P–H resonances, l 8.17, 1JPH=360 Hz and l 8.02,
1JPH=382 Hz. Only a single (Me3Si)2N resonance at l
0.27 is resolved. No evidence for coordinated THF is
Financial support for this work was provided by the
National Science Foundation, Grant CHE-8503550.
References
[1] (a) A.H. Cowley, R.A. Kemp, Chem. Rev. 85 (1985) 367. (b)
A.H Cowley, N.C. Norman, S. Quashie, J. Am. Chem. Soc. 106
(1984) 5007, (c) A.M. Arif, A.H. Cowley, S. Quashie, J. Chem.
Soc. Chem. Commun. (1986) 1437. (d) A.H. Cowley, D.N.
1
found in the H-NMR spectrum and this supports the
O-bonded trifluoroacetate linkage shown in Eq. 1.

20
H.-U. Reisacher et al. / Journal of Organometallic Chemistry 564 (1998) 13–20
Giolando, C.M. Nunn, M. Pakulski, D. Westmoreland, N.C.
Zsolnai, Organometallics 12 (1993) 2393.
Norman, J. Chem. Soc. Dalton Trans. (1988) 2127. (e) A.M.
Arif, A.H. Cowley, C.M. Nunn, S. Quashie, N.C. Norman, A.G.
Orpen, Organometallics 8 (1989) 1878.
[4] (a) R.W. Light, R.T. Paine, J. Am. Chem. Soc. 100 (1978) 2230.
(b) L.D. Hutchins, R.T. Paine, C.F. Campana, J. Am. Chem.
Soc. 102 (1980) 4521. (c) L.D. Hutchins, H.-U. Reisacher, G.L.
Wood, E.N. Duesler, R.T. Paine, J. Organomet. Chem. 335
(1987) 229. (d) D.A. Dubois, E.N. Duesler, R.T. Paine,
Organometallics 2 (1983) 1903. (e) L.D. Hutchins, E.N. Duesler,
R.T. Paine, Organometallics 3 (1984) 399. (f) W.F. McNamara,
E.N. Duesler, R.T. Paine, J.V. Ortiz, P. Ko¨lle, H. No¨th,
Organometallics 5 (1986) 380. (g) R.T. Paine, W.F. McNamara,
J.F. Janik, E.N. Duesler, Phosphorus Sulfur 30 (1987) 241. (h)
H.-U. Reisacher, E.N. Duesler, R.T. Paine, Chem. Ber. 129
(1996) 279. (i) H.-U. Reisacher, W.F. McNamara, E.N. Duesler,
R.T. Paine, Organometallics in press. (j) H.-U. Reisacher, E.N.
Duesler, R.T. Paine, J. Organomet. Chem. in press.
[5] H.-U. Reisacher, unpublished results.
[6] W.F. McNamara, Ph.D. Thesis, University of New Mexico,
1987.
[7] E.O. Fischer, Inorg. Synth. 7 (1963) 136.
[8] W.F. McNamara, H.-U. Reisacher, E.N. Duesler, R.T. Paine,
Organometallics 7 (1988) 1313.
[9] J. Emsley, D. Hall, The Chemistry of Phosphorus, Harper and
Row, New York, 1979.
[2] (a) E. Gross, K. Jo¨rg, K. Fiederling, A. Go¨ttlein, W. Malisch, R.
Boese, Angew. Chem. Int. Ed. Engl. 23 (1984) 738. (b) K. Jo¨rg,
W. Malisch, W. Reich, A. Meyer, U. Schubert, Angew. Chem.
Int. Ed. Engl. 25 (1986) 92. (c) W. Malisch, K. Jo¨rg, U.
Hofmockel, M. Schmeusser, R. Schemm, W.S. Sheldrick, Phos-
phorus Sulfur, 30 (1987) 205. (d) W. Malisch, K. Jo¨rg, E. Gross,
M. Schmeusser, A. Meyer, Phosphorus Sulfur, 26 (1986) 25. (e)
R. Maisch, E. Ott, W. Buchner, W. Malisch, W.S. Sheldrick, W.
McFarlane, J. Organomet. Chem. 286 (1985) C31. (f) D. Gudat,
E. Niecke, W. Malisch et al., J. Chem. Soc. Chem. Commun.
(1985) 1687. (g) W. Malisch, R. Maisch, I.J. Colquhoun, W.J.
McFarlane, Organomet. Chem. 220 (1981) C1. (h) W. Malisch,
V.A. Hirth, T.A. Bright, H. Ko¨b, T.S. Ertel, S. Hu¨ckmann, H.
Bertagnolli, Angew. Chem. Intl. Ed. Eng. 31 (1992) 1525.
[3] (a) H. Lang, M. Leise, L. Zsolnai, Polyhedron 11 (1992) 1281.
(b) H. Lang, M. Leise, W. Imhof, Z. Naturforsch. 46b (1991)
1650. (c) H. Lang, M. Leise, L. Zsolnai, M. Fritz, J. Organomet.
Chem. 395 (1990) C30. (d) H. Lang, M. Leise, L. Zsolnai, J.
Organomet. Chem. 389 (1990) 325. (e) M. Leise, L. Zsolnai, H.
Lang, Polyhedron 12 (1993) 1257. (f) H. Lang, M. Leise, L.
.