Electrophilic addition of Ph3PAu+ to anionic alkoxy Fischer-type carbene complexes: A novel approach to metal-stabilized bimetallic vinyl ether complexes

Article abstract of DOI:10.1021/om020048g

The addition of the Ph₃PAu⁺ electrophile to deprotonated Fischer-type alkoxy(methyl)-carbene complexes of pentacarbonyl group 6 metals leads to the formation of novel vinyl ether complexes of gold coordinated to the pentacarbonylmetal moiety. X-ray structures and DFT calculations show that the greatest bonding contribution in the vinyl coordination to the M(CO)₅ fragment comes from the terminal, partially negatively charged, CH₂ carbon atom via partial end-on η¹-bonding rather than the usual η²-bonding of olefins. The corresponding positive charge from the asymmetric vinyl coordination is mainly delocalized onto the Ph₃PAu fragment, stabilizing this coordination mode. The use of W instead of Cr in the M(CO)₅ fragment, in otherwise isostructural compounds, results in somewhat greater asymmetry in the vinyl coordination, with the difference in the two M(CO)₅-η²-vinyl carbon bond lengths increasing from 0.252(11) A? (M = Cr) to 0.307(5) A? (M = W) in the solid state.

Full text of DOI:10.1021/om020048g

Organometallics 2002, 21, 3173-3181
3173
Electr op h ilic Ad d ition of P h 3P Au + to An ion ic Alk oxy
F isch er -Typ e Ca r ben e Com p lexes: A Novel Ap p r oa ch to
Meta l-Sta bilized Bim eta llic Vin yl Eth er Com p lexes
Helgard G. Raubenheimer,*,† Matthias W. Esterhuysen,† Alexey Timoshkin,‡
Yu Chen,‡ and Gernot Frenking‡
Department of Chemistry, University of Stellenbosch, Private Bag X1,
Matieland, 7602, South Africa, and Fachbereich Chemie, Philipps-Universita¨t Marburg,
Hans-Meerwein-Strasse, D-35032 Marburg, Germany
Received J anuary 23, 2002
The addition of the Ph3PAu+ electrophile to deprotonated Fischer-type alkoxy(methyl)-
carbene complexes of pentacarbonyl group 6 metals leads to the formation of novel vinyl
ether complexes of gold coordinated to the pentacarbonylmetal moiety. X-ray structures and
DFT calculations show that the greatest bonding contribution in the vinyl coordination to
the M(CO)5 fragment comes from the terminal, partially negatively charged, CH2 carbon
atom via partial end-on η1-bonding rather than the usual η2-bonding of olefins. The
corresponding positive charge from the asymmetric vinyl coordination is mainly delocalized
onto the Ph3PAu fragment, stabilizing this coordination mode. The use of W instead of Cr
in the M(CO)5 fragment, in otherwise isostructural compounds, results in somewhat greater
asymmetry in the vinyl coordination, with the difference in the two M(CO)5-η2-vinyl carbon
bond lengths increasing from 0.252(11) Å (M ) Cr) to 0.307(5) Å (M ) W) in the solid state.
In tr od u ction
addition of tributyl tin chloride to the â-deprotonated
carbene complex has been reported by McDonald et al.
and currently serves as the sole example in which an
organometallic vinyl ether is formed along this reaction
path.5 Furthermore, the reverse process, involving the
formation of Fischer-type ruthenium carbene complexes
from the insertion of π-coordinated vinyl ethers into
Ru-H bonds followed by R-H migration back to Ru, has
recently been described.6 This facile isomerization route
to carbene complexes is believed to be enabled by the
formation of a stable Ru-H bond and the presence of a
14e- Ru-complex fragment.
Although the above-mentioned examples highlight the
usefulness and synthetic potential of this alternative
reaction pathway (Scheme 1b) in carbene chemistry, it
is surprising, especially in the light of the amount of
research that has been carried out involving carbene
anion substitution reactions, that only a handful of
conversions following the hydrolytic reaction path are
known.7 Furthermore, nowhere, to our knowledge, have
the vinyl ether-M(CO)5 adducts suggested to form in
this reaction been isolated and structurally character-
ized. We now report the utilization of â-deprotonated
carbene complex anions as anionic vinyl synthons,
yielding, in a reaction with the Ph3PAu+ electrophile,
unique bimetallic gold(I) vinyl ether-group 6 metal
Since their discovery 38 years ago, Fischer-type
carbene complexes and their derivatives have proved
their worth as important building blocks and synthons
in organic and organometallic synthesis.1 One unique
and extremely useful characteristic of these compounds
is that the metal carbonyl moiety serves as a strong
electron-withdrawing group, making the protons on
groups attached to the carbene carbon highly acidic.
This discovery by Kreiter in 19682 sparked a plethora
of studies involving the addition of electrophiles to the
formed conjugate “enolate” anion to yield useful â-sub-
stituted carbene complexes (Scheme 1a). Recently Ber-
nasconi et al. determined kinetic and thermodynamic
parameters for the carbene deprotonation in acetoni-
trile/water mixtures.3 In interpreting the hydrolytic
decomposition of â-carbon CH-acidic carbene complexes
in a basic medium, weak vinyl ether-Cr(CO)5 π-com-
plexation, activating the coordinated vinyl ether frag-
ment toward further hydrolysis, is invoked. This alter-
native conversion (Scheme 1b) is related to the consecu-
tive â-deprotonation, metal reprotonation, and formal
reductive elimination of vinyl ethers initiated by weak
bases such as pyridine, as first observed by Fischer et
al.4 The formation of R-stannyl vinyl ethers from the
* To whom correspondence should be addressed. Fax: +2721 808
3849. Tel: +2721 808 3850. E-mail: hgr@maties.sun.ac.za.
† University of Stellenbosch.
(5) McDonald, F. E.; Schultz, C. C.; Chatterjee, A. K. Organometal-
lics 1995, 14, 3628.
(6) Coalter, J . N., III; Bollinger, J . C.; Huffman, J . C.; Werner-
Zwanziger, U.; Caulton, K. G.; Davidson, E. R.; Ge´rard, H.; Clot, E.;
Eisenstein, O. New J . Chem. 2000, 24, 9.
(7) (a) Fuchibe, K.; Iwasawa, N. Tetrahedron 2000, 56, 4907. (b)
McDonald, F. E.; Reddy, K. S.; D´ıaz, Y. J . Am. Chem. Soc. 2000, 122,
4304. (c) Bowman, J . L.; McDonald, F. E. J . Org. Chem. 1998, 63, 3680.
(d) McDonald, F. E. Chatterjee, A. K. Tetrahedron Lett. 1997, 38, 7687.
‡ Philipps-Universita¨t Marburg.
(1) For a comprehensive review on the synthetic applications of
Fischer carbene complexes see: de Meijere, A.; Schirmer, H.; Duetsch,
M. Angew. Chem., Int. Ed. 2000, 39, 3964, and references therein.
(2) Kreiter, C. G. Angew. Chem., Int. Ed. Engl. 1968, 7, 390.
(3) Bernasconi, C. F. Chem. Soc. Rev. 1997, 26, 299.
(4) Fischer, E. O.; Plabst, D. Chem. Ber. 1974, 107, 3326.
10.1021/om020048g CCC: $22.00 © 2002 American Chemical Society
Publication on Web 06/22/2002

3174 Organometallics, Vol. 21, No. 15, 2002
Raubenheimer et al.
Sch em e 1
Sch em e 2
complexes, [M(CO)5-{η2-Ph3PAuC(OR)dCH2}] [M ) Cr,
R ) Me (1)/Et (2); M ) Mo, R ) Me (3); M ) W, R ) Me
(4)/Et (5)]. The synthesis of an uncoordinated R-Ph3PAu
ethyl(vinyl) ether complex by substitution of the M(CO)5
metal fragments in 2 and 5 with PPh3, as well as by a
transmetalation reaction of R-ethoxyvinyllithium with
Ph3PAuCl, is also described. The asymmetric metal
π-bonding situation of some of the complexes was,
furthermore, analyzed by means of DFT calculations.
The formation of η2-coordinated M(CO)5-[Ph3PAu
alkyl(vinyl)ether] bimetallic complexes (1-5), via a
hydrolysis-type reaction pathway, can, on account of the
well-documented and successfully applied isolobal re-
lationship8 between Ph3PAu+ and H+, be described as
an “aurolysis” reaction. We accept as a working hypoth-
esis formation of the gold vinyl ether complex by
sequential auration of the metal carbonyl, formal reduc-
tive elimination, and vinyl double-bond coordination to
the M(CO)5 fragment.
Slippage of the η2-vinyl coordination toward η1-
coordination in general greatly activates olefin com-
plexes toward nucleophilic addition reactions.9 Such
activation is observed in the complexation of nonmeta-
lated vinyl ethers to group 6 M(CO)5 fragments and is
postulated as a step in the hydrolysis of Fischer car-
benes.3 The coordinated vinyl double bonds are activated
toward nucleophilic addition reactions (usually base
hydrolysis with OH-) upon asymmetric coordination.
Corresponding aldehyde and alcoholic hydrolysis prod-
ucts are found among decomposition products. Test
reactions to prepare gold-free M(CO)5-ethyl(vinyl) ether
complexes in neutral media by irradiation of group 6
Resu lts a n d Discu ssion
Electr op h ilic Ad d ition of th e P h 3P Au + F r a g-
m en t to Dep r oton a ted F isch er -Typ e Alk oxy(m eth -
yl)ca r ben e Com p lexes of P en ta ca r bon yl Gr ou p 6
Meta ls. The syntheses of complexes 1-5 (Scheme 2)
were carried out in thf at -78 °C, although some
manipulations occurred at room temperature. Product
separation of dark yellow to brown, oily reaction mix-
tures (45-71% yields after separation) was carried out
by low-temperature (-15 °C) silica gel column chroma-
tography with pentane/diethyl ether (10:1) as eluant,
followed by crystallization from a diethyl ether solution
layered with pentane at -20 °C. The reaction is char-
acterized by alkenyl transmetalation and the concomi-
tant, remarkably strong, asymmetric coordination of the
vinyl double bond to the M(CO)5 fragment.
(8) (a) Hall, K. K.; Mingos, D. M. P. Prog. Inorg. Chem. 1984, 32,
237. (b) Evans, D. G.; Mingos, D. M. P. J . Organomet, Chem. 1982,
232, 171. (c) Hoffmann, R. Angew. Chem., Int. Ed. Engl. 1982, 21, 711.
(9) Eisenstein, O.; Hoffmann, R. J . Am. Chem. Soc. 1981, 103, 4308.

Metal-Stabilized Bimetallic Vinyl Ether Complexes
Organometallics, Vol. 21, No. 15, 2002 3175
Sch em e 3
Sch em e 4
M(CO)6 with UV light in thf followed by addition of
ethyl(vinyl) ether also resulted in the formation of a
mixture of decomposition and hydrolysis products,
including acetaldehyde and ethanol (NMR). When com-
peting ligands (L′), e.g., pyridine, are present in the
reaction mixture, free vinyl ether and M(CO)5L′ prod-
ucts can, however, be isolated.4 In contrast to the above-
mentioned findings, activation of the M(CO)5-coordi-
nated gold vinyl ethers in complexes 1-5 toward
hydrolysis was not observed. In fact, 1-5 are stable in
mildly basic or acidic environments and could be puri-
fied effectively by silica gel column chromatography.
This unique stability of the gold-vinyl ether asymmetric
π-complexation can be ascribed to zwitterionic resonance
stabilization of the partial positive charge on the R-vinyl
carbon through delocalization to the Ph3PAu fragment
(structure D in Scheme 3; AudC double bond is purely
illustrative for positive charge delocalization to Au).
Evidence for such an assumption is presented in the
spectroscopic, computational, and X-ray structure sec-
tions.
Syn th esis a n d Isola tion of r-P h 3P Au Eth yl(vin -
yl) Eth er (6). To investigate the effects that coordina-
tion of the vinyl moiety to the M(CO)5 groups in 1-5
has on the vinyl ether, the uncoordinated R-Ph3PAu
ethyl(vinyl)ether complex (6) was isolated and charac-
terized. Complex 6 could be obtained in two ways: by
freeing the η2-coordinated Ph3PAu ethyl(vinyl) ether
units in 2 and 5 with a stronger coordinating ligand
(e.g., PPh3) or by the transmetalation reaction of
R-ethoxyvinyllithium with Ph3PAuCl in thf (Scheme 4).
The substitution reaction was carried out by the
addition of PPh3 to an ether solution of 2 or 5 at -15
°C, after which 6 was purified by column chromatogra-
phy (SiO2), followed by crystallization from thf layered
with pentane at -20 °C (75% yield after separation).
In the transmetalation reaction R-ethoxyvinyllithium,
t
prepared from BuLi and ethyl vinyl ether, was reacted
with 1 molar equiv of Ph3PAuCl in thf at -78 °C.
Complex 6 was mechanically separated in low yield as
colorless crystalline needles after crystallization of the
reaction mixture from thf/pentane (-20 °C). The balance
of crystals consisted mainly of unreacted Ph3PAuCl
(NMR, TLC).
1
Sp ectr oscop ic Ch a r a cter iza tion of 1-6. The H
NMR spectra of 1-6 (summarized in Table 1) are
characterized, in particular, by two distinctive signals,
each integrating for a single proton and representing
two chemically nonequivalent vinyl protons. For the Ph3-
PAu methyl(vinyl) ether π-complexes of Cr(CO)5, Mo-
(CO)5, and W(CO)5 (1, 3, and 4), these signals appear
as broadened or doublet resonances at δ 2.23, 2.66, and
2.73 and doublet resonances at δ 3.80, 4.26, and 4.17,
respectively. The signals at δ 3.80, 4.26, and 4.17 are
assigned to the vinyl protons trans to the Ph3PAu
fragment coupling with the phosphorus atom across the
vinyl group and the gold atom. Although all the signals
for the vinyl proton cis to the Ph3PAu fragment at δ
4
2.23, 2.66, and 2.73 show broadening, a 1.2 Hz J P-H
coupling to the phosphorus atom is only observed for
2
the tungsten complex (4). No geminal J H-H coupling

3176 Organometallics, Vol. 21, No. 15, 2002
Raubenheimer et al.
Ta ble 1. Selected NMR Da ta for Com p lexes 1-6
1Ha 13C{1H}b
31P{1H}c
Au-P
P-Au-CdCHcis
2.23 (br s, 1H)
P-Au-CdCHtrans
P-Au-CdCH2
Au-C
4
3
2
1d
2e
3e
4e
5e
6e
3.80 (d, J P-H ) 8.2 Hz, 1H)
56.3 (d, J P-C ) 8.7 Hz)
191.4 (d, J P-C ) 124.5 Hz)
41.6 (s)
41.4 (s)
40.3 (s)
40.5 (s)
40.8 (s)
42.9 (s)
4
3
2
2.16 (br s, 1H)
2.66 (br s, 1H)
3.71 (d, J P-H ) 8.4 Hz, 1H)
55.6 (d, J P-C ) 8.4 Hz)
192.1 (d, J P-C ) 120.9 Hz)
4
3
2
4.26 (d, J P-H ) 8.6 Hz, 1H)
61.7 (d, J P-C ) 6.0 Hz)
186.0 (d, J P-C ) 134.2 Hz)
4
4
3
2
2.73 (d, J P-H ) 1.2 Hz, 1H)
4.17 (d, J P-H ) 8.1 Hz, 1H)
57.1 (d, J P-C ) 9.8 Hz)
185.3 (d, J P-C ) 124.5 Hz)
4
4
3
2
2.71 (d, J P-H ) 1.7 Hz, 1H)
4.13 (d, J P-H ) 8.0 Hz, 1H)
56.3 (d, J P-C ) 9.3 Hz)
185.2 (d, J P-C ) 121.3 Hz)
4
3
2
3.76 (br s, 1H)
4.64 (d, J P-H ) 9.4 Hz, 1H)
94.4 (d, J P-C ) 6.7 Hz)
202.5 (d, J P-C ) 129.8 Hz)
a
b
d
600 MHz. 150 MHz. c 121.4 MHz. Measured in CDCl3 at 25 °C. e Measured in CD2Cl2 at 25 °C.
between the vinyl protons is observed. The 1H reso-
nances for the methoxy-CH3 protons in 1, 3, and 4 are
found as singlets at δ 3.92, 3.83, and 3.85, roughly 1
ppm upfield from the signals for the same protons in
the corresponding methoxy(methyl)carbene starting
complexes.10
for R-Cvinyl compared to δ 55.6-61.7 and 185.2-192.1
in 1-5). Such downfield shifts upon de-coordination of
olefins from transition metals are common and can be
ascribed to an increase in s-character of the vinyl carbon
hybridization (partial sp3 character in 1-5 to pure sp2
character in 6). Furthermore, it was found that this
deshielding upon de-coordination of the vinyl ether
moieties in complexes 1-5 is much more pronounced
for the â-vinyl than for the R-vinyl carbon atom. The
13C chemical shifts for the â-vinyl carbon atoms, when
comparing the 13C NMR spectrum of the uncoordinated
gold vinyl ether complex (6) to those of 1-5, lie between
32.7 and 38.8 ppm downfield compared to downfield
shifts of between 10.4 and 17.3 ppm observed for the
R-vinyl carbon atom upon vinyl de-coordination. This
finding suggests a greater bonding contribution by the
â-vinyl carbon atom to the M(CO)5 fragment, with the
R-vinyl carbon atom retaining more of its sp2 character
after coordination.
The 13C{1H} NMR signals for the η2-coordinated
â-vinyl carbons in 1, 3, and 4 (Table 1) appear as
doublets at δ 56.3, 61.7, and 57.1, while those for the
R-vinyl carbons, bonded directly to the Ph3PAu frag-
ments, emerge as doublets (2J C-P ) 124.5-134.2 Hz)
at δ 191.4, 186.0, and 185.3. The 13C resonances for the
OCH3 groups in 1, 3, and 4 occur at ∼δ 61, nearly 10
ppm upfield from the signals for the same resonances
in the corresponding metal pentacarbonyl methoxy-
(methyl)carbene complexes.10
1
The H NMR spectra of the η2-coordinated M(CO)5-
[Ph3PAu ethyl(vinyl) ether] π-complexes [2 (M ) Cr) and
5 (M ) W)] are similar to those of 1, 3, and 4 with
respect to the cis and trans vinyl proton resonances,
which appear at δ 2.16 and 2.71 and δ 3.71 and 4.13,
This interpretation of the NMR spectra is supported
by the X-ray structures of 1 and 4, which show the
distinct presence of asymmetric η2-vinyl ether coordina-
tion modes. For the R-vinyl carbon atom to retain more
sp2 character than the â-vinyl carbon, some π-bonding
contribution from either the gold atom or the alkoxy
group must occur (as proposed by resonance structures
4
respectively. Again, a 1.7 Hz J P-H coupling in the
broadened doublet signal for the cis vinyl proton is
observed only for the tungsten complex (5). The 1H
signals for the CH2 protons in the ethoxy groups in 2
and 5, however, display a complex doublet of doublets
of quartets multiplicity, which is rationalized as fol-
lows: The CH2 protons in the ethoxy groups are dias-
tereotopic, giving rise to separate signals for each proton
(δ 4.26 and 4.42 in 2 and δ 4.06 and 4.42 in 5). The
quartet structure exhibited by each of these signals is
1
C and D in Scheme 3). Since the H and 13C resonances
for the alkoxy-CH3 and -CH2 atoms appear appreciably
upfield compared to their positions in the carbene
starting material (in which some double-bond character
is ascribed to the Ccarbene-OR bond),10,11 it can be
assumed that delocalization of the partial positive
charge on the R-vinyl carbon to the alkoxy fragment is
minimal and that the greatest positive charge delocal-
ization takes place to the Ph3PAu moiety (resonance
structure D). This interpretation is strengthened by the
13C chemical shifts measured for the R-vinyl carbon
atom in 1-5 (δ 185.2-192.1), which also support partial
carbene character for these atoms,12 as well as by DFT
calculations carried out for the PH3 analogue of 1, which
report a partial positive charge (+0.28e) situated on the
gold atom.
31P{1H} spectra of 1-5 show singlet signals between
40.3 and 41.6 ppm and are consistent with resonances
for PPh3 on positive or partially positive Ph3PAu frag-
ments reported in the literature.13 Resonance structure
D is thus suggested as the most important contributing
structure to the asymmetry of 1-5.
3
ascribed to J H-H coupling with the terminal CH3
protons in the ethoxy group. The signals are then
2
further split into doublets by J H-H geminal coupling.
The 13C{1H} NMR spectra of 2 and 5 compare well to
those found for 1, 3, and 4, with the doublet resonances
for the η2-coordinated R- and â-vinyl carbons appearing
at δ 192.1 and 55.6 and δ 185.2 and 56.3, respectively.
The effect of the η2-vinyl coordination to the electron-
withdrawing M(CO)5 fragments in 1-5 on the electronic
environment of the vinyl group can be observed clearly
by comparing the NMR spectra of the free R-Ph3PAu
ethyl(vinyl) ether fragment (6) to those of complexes
1
1-5. In the H NMR spectrum of 6 the signal for the
cis vinyl proton appears as a broadened singlet at δ 3.76,
roughly 1.0-1.5 ppm downfield compared to the same
resonances in complexes 1-5. Similarly, the doublet
signal for the trans vinyl proton in 6 at δ 4.64 is roughly
0.5-1.0 ppm downfield from its position in 1-5. Also,
13C NMR signals for the free vinyl carbon atoms in 6
lie downfield compared to the coordinated vinyl carbon
atoms in complexes 1-5 (δ 94.4 for â-Cvinyl and δ 202.5
(11) Mills, O. S.; Redhouse, A. D. J . Chem. Soc. (A) 1968, 642.
(12) (a) Raubenheimer, H. G.; Desmet, M.; Kruger, G. J . J . Chem.
Soc., Dalton Trans. 1995, 2067. (b) Desmet, M.; Raubenheimer, H. G.;
Kruger, G. J . Organometallics 1997, 16, 3324. (c) Raubenheimer, H.
G.; Olivier, P. J .; Lindeque, L.; Desmet, M.; Hrusˇak, J .; Kruger, G. J .
J . Organomet. Chem. 1997, 544, 91.
(10) Fischer, E. O. Adv. Organomet. Chem. 1976, 14, 1.

Metal-Stabilized Bimetallic Vinyl Ether Complexes
Organometallics, Vol. 21, No. 15, 2002 3177
1
Comparison of the H and 13C NMR spectra of 6 to
those of nonmetalated ethyl(vinyl) ether shows the effect
of substituting the R-vinyl hydrogen atom with the
isolobal Ph3PAu moiety. Curiously, the 1H resonance for
the cis-â-vinyl hydrogen atom appears slightly downfield
(δ 3.94) compared to the corresponding signal in 6 (δ
3.76), while the signal for the trans-â-vinyl hydrogen
atom appears 0.5 ppm upfield at δ 4.14. Comparison of
the 13C NMR resonances is more fruitful. The R- and
â-vinyl carbon atoms in ethyl(vinyl) ether resonate at
δ 152.6 and 86.5, compared to δ 202.5 and 94.4 in
complex 6, indicating greater deshielding of these atoms
in 6. This can be ascribed to electron loss due to
σ-donation from the R-vinyl carbon atom to the Ph3PAu
fragment. The fact that the chemical shift of the â-vinyl
carbon atom also indicates slight deshielding upon
metalation (7.9 ppm), suggests that π-back-bonding
from the gold atom to the π*-orbitals of the vinyl ether
lowering the vinyl bond order and decreasing the
π-deshielding effect, is not significant in 6.
F igu r e 1. ORTEP18 view of the molecular structure of 1
showing atom-labeling scheme (using 50% probability
ellipsoids). Selected interatomic distances (Å) and angles
(deg): Au-C(7)
) 2.050(7), C(1)-C(7) ) 1.345(11),
Cr-C(1) ) 2.377(8), Cr-C(7) ) 2.629(7), C(7)-O(1) )
1.368(9), O(1)-C(8) ) 1.424(9), Au-P ) 2.291(2), Cr-C(2)
) 1.894(9), Cr-C(3) ) 1.904(9), Cr-C(4) ) 1.885(9),
Cr-C(5) ) 1.894(10), Cr-C(6) ) 1.847(10), Cr-C(1)-C(7)
) 85.0(5).
Positive ion FAB-MS of 1-6 exhibited mainly Ph3-
PAu+ (m/z 459) and (Ph3P)2Au+ (m/z 721) fragments and
molecular ions.
The infrared spectra (IR) of 1-5 were recorded in
pentane. The C4v-local metal carbonyl symmetry in 1-5
allows for three IR-active vibrational modes, two A1 (one
with weak intensity) and an intense E mode (a 2-fold
degenerate mode). The IR spectra of 1-5 all exhibit five
clearly separated absorption bands in the carbonyl
region, which could be assigned as follows: one weak
A1(1) vibrational mode between 2056 and 2064 cm-1
,
assigned to the CO symmetric stretching in the M(CO)4
plane; a strong A1(2) vibrational mode at ∼1910 cm-1
,
assigned to symmetric stretching of the single terminal
CO ligand trans to the olefin coordination; a weak B1
vibrational mode at ∼1976 cm-1 (IR-active due to
distortion of the M(CO)4 coordination plane by the large
and asymmetric Ph3PAu vinyl ether ligand), assigned
to out-of-plane bending of the CO ligands in the M(CO)4
plane. Finally, two strong vibrational modes at ∼1935
and ∼1924 cm-1 (due to lifting of E degeneracy) are
assigned to the asymmetric stretching of the CO ligands
in the M(CO)4 plane. Of all these, the A1 modes have
the greatest diagnostic value. Low-frequency A1 vibra-
tions (compared to literature examples)14 in complexes
of the type M(CO)5L, as is observed for 1-5 (∼1910
cm-1), are indicative of good σ-donating, but poor
π-accepting ligands (L). This result is also reflected in
the small reduction in the vinyl bond order and good
retention of sp2 geometry found for the coordinating
vinyl carbon atoms in the crystal structures of 1 and 4.
Together with the information obtained from the crystal
structures of 1 and 4, the IR spectra of 1-5 suggest that
back-donation of electrons from the M(CO)5 fragments
into the empty π*-orbitals of the olefins is minimal and
that coordination of the vinyl groups into the M(CO)5
F igu r e 2. ORTEP18 view of the molecular structure of 4
showing atom-labeling scheme (using 50% probability
ellipsoids). Hydrogen atoms on phenyl rings are omitted
for clarity. Selected interatomic distances (Å) and angles
(deg): Au-C(7) ) 2.067(4), C(1)-C(7) ) 1.378(5), W-C(1)
) 2.393(3), W-C(7) ) 2.700(4), C(7)-O(1) ) 1.423(4),
O(1)-C(8) ) 1.436(4), Au-P ) 2.294(1), W-C(2) )
2.030(4), W-C(3) ) 2.102(4), W-C(4) ) 2.048(5), W-C(5)
) 2.113(5), W-C(6) ) 1.935(4), W-C(1)-C(7) ) 87.1(2).
fragments in 1-5 is thus mainly as a result of σ-dona-
tion from the olefin. Furthermore, the fact that two
clearly separated and nondegenerate vibrational modes
(E in C4v symmetry) are observed bears testimony to
the size and asymmetry of the gold alkyl(vinyl) ether
ligands.
X-r a y Cr ysta l Str u ctu r es of 1 a n d 4. The crystal
and molecular structures of 1 and 4 (Figures 1 and 2)
were determined by X-ray diffraction techniques. Both
structures show Ph3PAu methyl vinyl ether moieties
coordinated in asymmetrical η2-fashion to a square
(13) (a) Ferna´ndez, E. J .; Lo´pez-de-Luzuriaga, J . M.; Monge, M.;
Olmos, E.; Gimeno, M. C.; Laguna, A.; J ones, P. G. Inorg. Chem. 1998,
37, 5532. (b) Bayler, A.; Schier, A.; Schmidbaur, H. Inorg. Chem. 1998,
37, 4353. (c) Chan, W.-H.; Mak, T. C. W.; Che, C.-M. J . Chem. Soc.,
Dalton Trans. 1998, 2275.
(14) (a) Cotton, F. A.; Kraihanzel, C. S. J . Am. Chem. Soc. 1962,
84, 4432. (b) Ainscough, E. W.; Brodie, A. M.; Furness, A. R. J . Chem.
Soc., Chem. Commun. 1971, 1357. (c) Magee, T. A.; Matthews, C. N.;
Wang, T. S.; Wotiz, J . H. J . Am. Chem. Soc. 1961, 83, 3200. (d) Brown,
R. A., Dobson, G. R. Inorg. Chim. Acta 1972, 6, 65.

3178 Organometallics, Vol. 21, No. 15, 2002
Raubenheimer et al.
pyramidal M(CO)5 [M ) Cr (1), M ) W (4)] fragment,
thus filling the octahedral coordination sphere com-
monly encountered for group 6 metals in the zero
oxidation state. The structures of 1 and 4 represent the
first X-ray structures of neutral group 6 metal carbonyl
compounds containing vinyl ether ligands. Analysis of
the difference in the M-η2 vinyl carbon bond lengths
(0.252(11) Å in 1 and 0.307(5) Å in 4) [∆(M-C) )
{M-C(7)} - {M-C(1)}] and M-C(1)-C(7) angles
[85.0(5)° and 87.1(2)° in 1 and 4] gives a clear indication
of the asymmetric bonding of the vinyl ethers and shows
that the asymmetry is greater in the structure of 4. Also,
the M-C(1) bond lengths in both structures are very
similar [Cr-C(1) ) 2.377(8) Å, W-C(1) ) 2.393(3) Å],
despite the substantial difference in atomic radius
between Cr and W [Cr ) 1.25 Å, W ) 1.37 Å],15
illustrating that C(1) is more involved in metal bonding
in 4 than in 1. Slippage of the η2-vinyl coordination
mode toward a η1-coordination is described by the
displacement of the olefin centroid from the metal center
(as defined by extension of the M-C(6) bond). The
calculated slip shifts in 1 and 4 (0.00 and 0.04 Å) show
that, although the olefin coordination is distinctly
asymmetric, no meaningful lateral slippage of the metal
toward either vinyl carbon atom has taken place. This
is also reflected in the small M-C(1)-C(7) angles
reported above, which are more than 20° from the
tetrahedral ideal of 109.5° for pure sp3 η1-coordination.
In all other known examples where similar asymmetric
coordination of an olefin to a metal carbonyl is observed
the geometry of the terminal coordinating CH2-carbon
atom is much closer to that of an sp3 carbon atom and
much greater slip shifts are observed.16 C(4)-C(2)-
C(7)-C(1) torsion angles of 9.4(5)° and 11.3(3)° in 1 and
4 show that the vinyl coordination is close to parallel
to the C(2)-M-C(4) coordination axis in the M(CO)5L
octahedra.
Olefin bond lengths [C(1)-C(7)] in 1 and 4 of
1.345(11) and 1.378(5) Å compare well to such bonds in
known noncoordinated metallo vinyl ethers17 and indi-
cate that, although formal π-complexation of the vinyl
ether has taken place, there is not much reduction in
the olefin bond order in the solid state (uncoordinated
vinyl ether CdC bond length in ref 17b is 1.340(5) Å).
The geometries of the coordinating vinyl carbon atoms
in 1 and 4 are slightly distorted from ideal sp2 hybrid-
ization, with the greatest deviations from planarity in
the mean squares plane defined by C(1), C(7), O(1), and
Au in 1 and 4 being 0.071(6) and 0.073(3) Å for C(7) in
both cases. The positions of the vinyl protons could be
determined from the difference Fourier map and sup-
port a slightly distorted sp2 hybridization for C(1) in
both structures. These results are in agreement with
spectroscopic data for 1 and 4, which suggest poor back-
donation of electrons from the metal to the π*-orbitals
of the olefin, thus conserving the sp2 geometry of the
coordinated vinyl ether moiety. A slightly greater
F igu r e 3. Two perspectives of the calculated geometry of
1M. Distances in Å, angles in deg.
decrease in vinyl bond order and distortion toward sp3
geometry is, however, observed in the vinyl bond of 4.
Au-C(7) bond lengths in 1 and 4 [2.050(7) and
2.067(4) Å] compare well with literature values in which
a gold(I) phosphine fragment is linked via carbon to
electron-withdrawing substituents.19 Furthermore, due
to the poor correlation between Au-C bond length and
bond order,12 the observed Au-C separations do not
exclude possible partial carbene character for these
bonds, as is suggested by the NMR spectroscopic results
and resonance structure D (Scheme 3). Reasons for the
significant difference in the C(7)-O(1) bond lengths in
1 and 4 [1.368(9) and 1.432(4) Å] are not clear. Lengths
for similar single bonds in noncoordinated metallo vinyl
ethers in the literature,17 however, correlate well with
the C(7)-O(1) separation observed in 1, suggesting that
the C(7)-O(1) bond in 1 is not shortened, but rather
that the C(7)-O(1) bond in 4 is lengthened. This
interpretation thus also supports resonance structure
D as the main contributing resonance form for these
complexes.
Distortion of the M(CO)5 units due to coordination of
the large and asymmetric Ph3PAu vinyl ether ligand is
described by deviation from planarity from the least
squares plane through M, C(2), C(3), C(4), and C(5) and
is calculated as -0.071(4), 0.049(4), -0.069(4),
0.049(4), and 0.043(3) Å in 1 and -0.090(2), 0.065(2),
-0.085(2), 0.064(2), and 0.045(2) Å in 4, respectively.
DF T Ca lcu la tion s. To analyze the bonding situation
in 1, we carried out DFT calculations of the model
compound 1M in which the PPh3 ligand of 1 is substi-
tuted by PH3. Figure 3 shows the optimized geometry
(15) Pauling, L. The Nature of the Chemical Bond, 3rd ed.; Cornell
University Press: Ithaca, NewYork, 1960.
(16) Kuhn, N.; Bohnen, H.; Blaser, D.; Boese, R. Chem. Ber. 1994,
127, 1405.
(17) (a) Baird, G. J .; Davies, S. G., J ones, R. H.; Prout, K.; Warner,
P. Chem. Commun. 1984, 745. (b) Veya, P.; Floriani, C.; Chiesi-Villa,
A.; Rizzoli, C. Organometallics 1994, 13, 214. (c) Xu, D.; Miki, K.;
Tanaka, M.; Kasai, N.; Yasuoka, N.; Wada, M. J . Organomet. Chem.
1989, 371, 267.
(18) Farrugia, L. J . J . Appl. Crystallogr. 1997, 30, 565.
(19) (a) Steinborn, D.; Becke, S.; Herzog, R.; Gunther, M.; Kircheisen,
R.; Stoeckli-Evans, H.; Bruhn, C. Z. Anorg. Allg. Chem. 1998, 624,
1303. (b) Raubenheimer, H. G.; Kruger, G. J .; Marais, C. F.; Hattingh,
J . T. Z.; Linford, L.; van Rooyen, P. H. J . Organomet. Chem. 1988,
355, 337. (c) Flo¨rke, U.; Haupt, H.-J .; J ones, P. G. Acta Crystallogr.,
Sect. C. (Cryst. Struct. Commun.) 1996, 52, 609.

Metal-Stabilized Bimetallic Vinyl Ether Complexes
Organometallics, Vol. 21, No. 15, 2002 3179
vinyl group (1M′). The calculations predict that this
isomer is 5.7 kcal/mol higher in energy than 1M. The
negatively charged terminal carbon atom is softer than
oxygen and is, thus, a better donor. We also calculated
the related isomers where oxygen is substituted by
sulfur. The DFT calculations predict that the vinyl
thioether ligand binds stronger through the sulfur atom
than through the vinyl group. The former isomer is 6.6
kcal/mol lower in energy than the latter. This means
that the relative stability of the isomers 1M and 1M′
changes when oxygen is substituted by sulfur. We are
investigating this theoretical prediction.
Su m m a r y
F igu r e 4. Contour line diagrams of the Laplacian distri-
2
bution ∇ F(r ) in 1M. Dashed lines show areas of electron
In this paper we have reported the synthesis of
asymmetrically coordinated yet stable vinyl ether com-
plexes of group 6 metal pentacarbonyls via an aurolysis
reaction of â-carbon deprotonated alkoxy Fischer-type
carbene anions with the Ph3PAu+ electrophile. Evidence
presented here strongly suggests that the asymmetric
vinyl coordination observed in the structures of these
compounds is stabilized by the delocalization of partial
positive charges in the polarized vinyl coordination
mode to the Ph3PAu moiety. This effectively allows the
isolation of the vinyl ether coordinated complex that has
been proposed as a transition state in the hydrolysis of
conventional methyl alkoxy Fischer-type carbene com-
plexes. Nowhere, to our knowledge, have such vinyl
ether-M(CO)5 adducts from this reaction been isolated
and structurally characterized. Quantum chemical cal-
culations show that the bonding between the chromium
atom and the vinyl moiety of the vinyl ether ligand
should be considered as η1-bonding of the terminal
carbanion rather than η2-bonding of an olefin. The
isolation of these compounds, furthermore, confirms this
reaction pathway as the one by which the hydrolytic
decomposition of Fischer carbene complexes takes place.
This reaction also serves as a novel and effective method
for the preparation of gold vinyl ethers. Currently we
are investigating the use of this type of conversion for
the preparation of the first gold vinylamines and mer-
capto vinyl ethers.
2
depletion (∇ F(r ) > 0), while solid lines show areas of
2
electron concentration (∇ F(r ) < 0). The solid lines between
Cr and C1 and between C1 and C7 are the bond paths.
There is no bond path between Cr and C7.
and the most important bond lengths and angles of 1M.
The calculated bond lengths and angles of 1M are very
similar to the experimental data of 1. The theoretical
value for the C(1)-C(7) distance is 1.381 Å, which is
slightly longer than experiment. More important are the
Cr-C bond lengths of the coordinated vinyl group. The
calculations also give rather different distances for
C(1)-Cr ) 2.464 Å and C(7)-Cr ) 2.786 Å, indicating
stronger bonding of chromium with C(1) than with C(7).
A topological analysis of the electron density distribu-
tion20 suggests that the Cr-vinyl bonding takes place
mainly via carbon atom C(1) of the ligand. The Lapla-
cian distribution of 1M, which is given in Figure 4,
shows that the area of π-charge concentration at the
terminal C(1) atom of the vinyl ether ligand is distorted
toward the chromium atom. There is a droplet-like
appendix of charge concentration which points toward
Cr. Even more revealing concerning the bonding situ-
ation are the calculated bond paths. Figure 4 shows that
there is a bond path between C(1) and Cr but not
between C(7) and Cr. The shape of the Laplacian
distribution and the calculated bond paths show clearly
that the chromium atom is primarily bonded to C(1) and
that there are only secondary interactions between C(7)
and Cr. The calculated charge distribution given by the
NBO analysis21 gives a large negative partial charge at
C(1) (-0.61e) but a small positive charge at C(7)
(+0.03e). Positive partial charges are also calculated for
Au (+0.28e) and the PH3 ligand (+0.23e). This means
that the positive charge is delocalized over the C(7)-
Au-PH3 moiety. Despite the charge distribution, how-
ever, the calculations give a nearly planar arrangement
of the vinyl moiety. We conclude that the bonding
interaction between the coordinating vinyl ligand and
chromium in 1M and 1 is best described as η1-bonding
of a terminal carbanion rather than η2-bonding of an
olefin.
Exp er im en ta l Section
All procedures were carried out under a dry nitrogen
atmosphere using standard Schlenk and vacuum-line tech-
niques. All solvents were dried and purified by conventional
methods and freshly distilled under nitrogen shortly before
use. Unless otherwise stated all common reagents were used
as obtained from commercial suppliers without further puri-
fication. Ethyl(vinyl) ether was distilled under nitrogen gas
before use. NMR spectra were recorded on Varian INOVA 600
(600 MHz for 1H, 151 MHz for 13C{1H}, and 243 MHz for 31P-
{1H}) or Varian VXR 300 (300 MHz for 1H, 75.4 MHz for 13C-
{1H}, and 121.5 MHz for 31P{1H}) NMR spectrometers. 1H and
13C chemical shifts are reported in ppm relative to the H and
1
13C residue of the deuterated solvents. 31P chemical shifts are
reported in ppm relative to an 85% H3PO4 external standard
solution. IR spectra were recorded on a Perkin-Elmer 1600
series FTIR spectrometer. FAB-MS were recorded on a Mi-
cromass DG 70/70E mass spectrometer using xenon gas as
bombardment atoms and m-nitrobenzyl alcohol as matrix.
Flash column chromatography was performed with “flash
grade” silica (SDS 230-400 mesh).
The vinyl ether ligand might also bind to the M(CO)5
moiety via the oxygen atom of the ether group. We also
calculated the isomer of 1M where the ligand is bonded
to chromium through the oxygen atom rather then the
(20) Bader, R. F. W. Atoms in Molecules: A Quantum Theory;
Clarendon Press: Oxford, 1990.
(21) Reed, A. E.; Curtiss, L. A.; Weinhold F. Chem. Rev. 1988, 88,
899.
Rep r esen ta tive Exp er im en ta l P r oced u r es for th e Syn -
th esis of 1-5. BuLi (0.5 mL, 1.6 M, 1.2 equiv) was added to
n

3180 Organometallics, Vol. 21, No. 15, 2002
Raubenheimer et al.
DENZO-SMN.23 The structures were solved by the heavy atom
method (SHELXS)24 and refined anisotropically for non-
hydrogen atoms by full-matrix least squares calculations
(SHELXL-97)24 on F2. All hydrogen atoms in 1 and 4 were
placed in calculated positions, except those on the coordinating
vinyl moiety, which were found on the difference Fourier map
and refined isotropically.
Ta ble 2. Cr ysta llogr a p h ic Da ta for 1 a n d 4
1
4
chemical formula
MW (g/mol)
cryst syst
space group
a (Å)
C
26H20O6PAuCr
C26H20O6PAuW
840.21
monoclinic
P21/c
10.698(1)
12.106(1)
20.352(1)
90
94.423(1)
90
2627.9(4)
4
2.124
150(2)
10.048
708.36
monoclinic
P21/c
10.6147(4)
12.0314(4)
20.4580(9)
90
99.705(2)
90
2575.3(2)
4
1.827
173(2)
6.212
Th eor etica l Ca lcu la tion s. The geometries have been
optimized at the gradient-corrected DFT level using the three-
parameter fit of the exchange-correlation potential suggested
by Becke25 in conjunction with the LYP26 exchange potential
(B3LYP).27 A quasi-relativistic small-core ECP with a (441/
2111/N1) valence basis set for the metal atoms (N ) 4 for Cr
and N ) 2 for Au)28 and 6-31G(d) all-electron basis sets29 for
the other atoms have been employed in the geometry optimi-
zations. This is our standard basis set II.30 The nature of the
stationary points was examined by calculating the Hessian
matrix at B3LYP/II. All structures are energy minima on the
potential energy surface. The calculations have been performed
with the program package Gaussian 98.31 The topological
analysis of the electron density distribution was carried out
with the programs SADDLE, GRID, SCHUSS, CPLOT, and
BADERCAT.32
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
volume (Å3)
Z
dcalcd (g/cm3)
temp (K)
µ
Mo KR (cm-1
)
2θmax (deg)
radiation
25.49
Mo KR, graphite
monochromated
27.00
Mo KR, graphite
monochromated
cryst size (mm)
index range
0.012 × 0.02 × 0.15 0.13 × 0.25 × 0.25
-12 e h e 12
-14 e k e 12
-20 e l e 24
-13 e h e 10
-15 e k e 14
-26 e l e 22
13 102
no. of reflns collected 12 767
Sp ectr oscop ic d a ta for 1: 1H NMR (600 MHz, CDCl3, 298
no. of ind reflns
4787
5627
4
(Rint ) 0.0880)
(Rint ) 0.0272)
K) δ 2.23 (br s, 1H, cis-CdCH2), 3.80 (d, J trans
) 8.2 Hz,
P-H
no. of obsd reflns
refinement
params
3158
4872
1H, trans-CdCH2), 3.92 (s, 3H, OCH3), 7.4-7.6 (m, 15H, Ph);
SHELXL on F2
325
SHELXL on F2
326
13C{1H} NMR (150 MHz, CDCl3, 298 K) δ 56.3 (d, J P-C ) 8.7
3
2
Hz, dCH2), 61.3 (s, OCH3), 129.7 (d, J P-C ) 10.9 Hz, ortho-
Ph), 130.1 (d, J P-C ) 53.4 Hz, ipso-Ph), 132.1 (s, para-Ph),
R1 (Fo > 2σFo)
wR2 (all data)
0.0454
0.0867
0.0219
0.0461
1
3
2
134.6 (d, J P-C ) 13.6 Hz, meta-Ph), 191.4 (d, J P-C ) 124.5
Hz, C-Au), 219.5 (s, cis-CO), 227.2 (s, trans-CO); 31P{1H} NMR
(243 MHz, CDCl3, 298 K) δ 41.6 (s, PPh3); positive ion FAB-
MS m/z 708 (M+); IR (cm-1, pentane solution in NaCl cell)
ν(CO) 1910 (s, A1(2)), 1924, 1938 (2 × s, “E”), 1978 (w, B1),
2057 (w, A1(1)). Anal. Calcd for C26H20O6PCrAu: C, 44.08; H,
2.85; O, 13.55. Found: C, 44.25; H, 2.98; O, 13.26.
a solution of the alkoxy(methyl) carbene complex (0.8 mmol)
in 15 mL of thf cooled to -78 °C. The mixture was stirred at
that temperature for 30 min, after which 1 equiv of Ph3PAuCl
(395 mg) or Ph3PAuNO3 (417 mg) was added to the solution.
The mixture was then allowed to warm to room temperature
over a period of 3 h. Removal of the solvent in vacuo resulted
in dark yellow to brown oily residues containing a mixture of
products (TLC). The products were isolated in moderate yields
(67% (1), 71% (2), 53% (3), 45% (4), and 63% (5)) as broad
yellow bands by means of low-temperature (-15 °C) silica gel
column chromatography (pentane/diethyl ether, 10:1).
Syn th esis of 6: Su bstitu tion Rea ction . PPh3 (1 equiv,
0.05 mmol, 131 mg) was added to a cooled (-15 °C) ether
solution of 2 or 5 (0.5 mmol). The mixture was allowed to warm
to room temperature over a period of 30 min. Removal of the
solvent in vacuo resulted in a powdery, light yellow mixture
containing 6 and (CO)5MPPh3 (vide-NMR). 6 was purified by
low-temperature (-15 °C) flash silica gel column chromatog-
raphy (thf/pentane, 1:2), followed by crystallization from thf
layered with pentane at -20 °C (75% yield after separation).
Tr a n sm eta la tion Rea ction . A solution of R-ethoxyvinyl-
lithium (0.8 mmol) in 15 mL of thf was prepared analogously
to the procedure for the preparation of R-methoxyvinyllithium
described by Baldwin et al.22 While stirring this solution at
-78 °C, 1 equiv of Ph3PAuCl (0.8 mmol, 395 mg) was added,
after which it was allowed to warm to room temperature over
a period of 3 h. Removal of the solvent in vacuo resulted in
milky oily residues containing the product and unreacted Ph3-
PAuCl. Complex 6 was isolated as needles in low yield (9%)
by crystallization from thf/pentane mixtures at -20 °C. Yields
were not optimized.
Sp ectr oscop ic d a ta for 2: 1H NMR (600 MHz, CD2Cl2,
3
298 K) δ 1.22 (t, J H-H ) 7.1 Hz, 3H, CH3), 2.16 (br s, 1H,
4
cis-CdCH2), 3.71 (d, J trans
) 8.4 Hz, 1H, trans-CdCH2),
P-H
3
2
4.26 (dq, J H-H ) 10.0 Hz, J H-H ) 7.1 Hz, 1H, OCH2), 4.42
2
3
(dq, J H-H ) 10.0 Hz, J H-H ) 7.1 Hz, 1H, OCH2), 7.4-7.7 (m,
15H, Ph); 13C{1H} NMR (150 MHz, CD2Cl2, 298 K) δ 15.1 (s,
CH3), 55.6 (d, 3J P-C ) 8.4 Hz, dCH2), 70.6 (s, OCH2), 129.6 (d,
2J P-C ) 11.7 Hz, ortho-Ph), 130.0 (d, J P-C ) 53.7 Hz, ipso-
1
(23) Otwinowski, Z.; Minor, W. Methods Enzymol. 1997, 276, 307.
(24) Sheldrick, G. M. SHELX-97. Program for crystal structure
analysis; University of Go¨ttingen: Germany, 1997.
(25) Becke, A. D. J . Chem. Phys. 1993, 98, 5648.
(26) Lee, C.; Yang, W.; Parr, R. G. Phys. Rev. B 1988, 37, 785.
(27) Stevens, P. J .; Devlin, F. J .; Chablowski, C. F.; Frisch, M. J . J .
Phys. Chem. 1994, 98, 11623.
(28) Hay, P. J .; Wadt, W. R. J . Chem. Phys. 1985, 82, 299.
(29) (a) Ditchfield, R.; Hehre, W. J .; Pople, J . A. J . Chem. Phys. 1971,
54, 724. (b) Hehre, W. J .; Ditchfield, R.; Pople, J . A. J . Chem. Phys.
1972, 56, 2257.
(30) Frenking, G.; Antes, I.; Bo¨hme, M.; Dapprich, S.; Ehlers, A. W.;
J onas, V.; Neuhaus, A.; Otto, M.; Stegmann, R.; Veldkamp, A.;
Vyboishchikov, S. F. In Reviews in Computational Chemistry; Lipkow-
itz, K. B., Boyd, D. B., Eds.; VCH: New York, 1996; Vol. 8, pp 63-
144.
(31) Frisch, M. J .; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.;
Robb, M. A.; Cheeseman, J . R.; Zakrzewski, V. G.; Montgomery, J . A.,
J r.; Stratmann, R. E.; Burant, J . C.; Dapprich, S.; Millam, J . M.;
Daniels, A. D.; Kudin, K. N.; Strain, M. C.; Farkas, O.; Tomasi, J .;
Barone, V.; Cossi, M.; Cammi, R.; Mennucci, B.; Pomelli, C.; Adamo,
C.; Clifford, S.; Ochterski, J .; Petersson, G. A.; Ayala, P. Y.; Cui, Q.;
Morokuma, K.; Malick, D. K.; Rabuck, A. D.; Raghavachari, K.;
Foresman, J . B.; Cioslowski, J .; Ortiz, J . V.; Stefanov, B. B.; Liu, G.;
Liashenko, A.; Piskorz, P.; Komaromi, I.; Gomperts, R.; Martin, R. L.;
Fox, D. J .; Keith, T.; Al-Laham, M. A.; Peng, C. Y.; Nanayakkara, A.;
Gonzalez, C.; Challacombe, M.; Gill, P. M. W.; J ohnson, B. G.; Chen,
W.; Wong, M. W.; Andres, J . L.; Head-Gordon, M.; Replogle, E. S.;
Pople, J . A. Gaussian 98, revision A.8; Gaussian, Inc.: Pittsburgh, PA,
1998.
X-r a y Cr ysta llogr a p h y. The crystal and refinement data
for 1 and 4 are summarized in Table 2. X-ray quality yellow
platelet single crystals of 1 and 4 were obtained by crystal-
lization from concentrated diethyl ether solutions layered with
pentane at -20 °C. Data were collected on an Enraf-Nonius
KappaCCD diffractometer using graphite-monochromated Mo
KR radiation (λ ) 0.71073 Å) and scaled and reduced using
(22) Baldwin, J . E.; Ho¨fle, G. A.; Lever, O. W., J r. J . Am. Chem.
Soc. 1974, 96, 7125.
(32) Biegler-Ko¨nig, F. W.; Bader, R. F. W.; Ting-Hua, T. J . J .
Comput. Chem. 1982, 3, 317.

Metal-Stabilized Bimetallic Vinyl Ether Complexes
Organometallics, Vol. 21, No. 15, 2002 3181
3
2
3
Ph), 131.9 (s, para-Ph), 134.5 (d, J P-C ) 12.4 Hz, meta-Ph),
4.42 (dq, J H-H ) 9.5 Hz, J H-H ) 7.1 Hz, 1H, OCH2), 7.4-7.7
(m, 15H, Ph); 13C{1H} NMR (150 MHz, CD2Cl2, 298 K) δ 15.0
(s, CH3), 56.3 (d, 3J P-C ) 9.3 Hz, dCH2), 70.3 (s, OCH2), 129.5
(d, 2J P-C ) 12.4 Hz, ortho-Ph), 130.7 (d, 1J P-C ) 47.8 Hz, ipso-
2
192.1 (d, J P-C ) 120.9 Hz, C-Au), 219.3 (s, cis-CO), 227.0 (s,
trans-CO); 31P{1H} NMR (243 MHz, CD2Cl2, 298 K) δ 41.4 (s,
PPh3); positive ion FAB-MS m/z 722 (M+); IR (cm-1, pentane
solution in NaCl cell) ν(CO) 1910 (s, A1(2)), 1923, 1938 (2 × s,
“E”), 1978 (w, B1), 2056 (w, A1(1)). Anal. Calcd for C27H22O6-
PCrAu: C, 44.89; H, 3.07; O, 13.29. Found: C, 45.12; H, 3.02;
O, 13.38.
3
Ph), 131.9 (s, para-Ph), 134.5 (d, J P-C ) 12.9 Hz, meta-Ph),
2
185.2 (d, J P-C ) 121.3 Hz, C-Au), 200.3 (s, cis-CO), 204.3 (s,
trans-CO); 31P{1H} NMR (121.4 MHz, CD2Cl2, 298 K) δ 40.8
(s, PPh3); positive ion FAB-MS m/z 854 (M+); IR (cm-1, pentane
solution in NaCl cell) ν(CO) 1910 (s, A1(2)), 1924, 1935 (2 × s,
“E”), 1976 (w, B1), 2064 (w, A1(1)). Anal. Calcd for C27H22O6-
PWAu: C, 37.96; H, 2.60; O, 11.24. Found: C, 37.81; H, 2.45;
O, 11.38.
Sp ectr oscop ic d a ta for 3: 1H NMR (600 MHz, CD2Cl2,
298 K) δ 2.66 (br s, 1H, cis-CdCH2), 3.83 (s, 3H, OCH3), 4.26
4
(d, J trans
) 8.6 Hz, 1H, trans-CdCH2), 7.4-7.7 (m, 15H,
P-H
Ph); 13C{1H} NMR (150 MHz, CD2Cl2, 298 K) δ 61.1 (s, OCH3),
61.7 (d, 3J P-C ) 6.0 Hz, dCH2), 129.5 (d, 2J P-C ) 12.0 Hz, ortho-
Sp ectr oscop ic d a ta for 6: 1H NMR (600 MHz, CD2Cl2,
1
3
Ph), 130.1 (d, J P-C ) 54.0 Hz, ipso-Ph), 131.9 (s, para-Ph),
298 K) δ 1.25 (t, J H-H ) 7.0 Hz, 3H, CH3), 3.76 (br s, 1H,
3
2
cis-CdCH2), 3.92 (q, 3J H-H ) 7.0 Hz, 2H, OCH2), 4.64 (d, J trans
134.4 (d, J P-C ) 14.5 Hz, meta-Ph), 186.0 (d, J P-C ) 134.2
Hz, C-Au), 201.5 (s, cis-CO), 206.1 (s, trans-CO); 31P{1H} NMR
(121.4 MHz, CD2Cl2, 298 K) δ 40.3 (s, PPh3); positive ion FAB-
MS m/z 752 (M+); IR (cm-1, pentane solution in NaCl cell)
ν(CO) 1910 (s, A1(2)), 1925, 1934 (2 × s, “E”), 1980 (w, B1),
2060 (w, A1(1)). Anal. Calcd for C26H20O6PMoAu: C, 41.51; H,
2.68; O, 12.76. Found: C, 41.45; H, 2.64; O, 12.90.
4
P
) 9.4 Hz, 1H, trans-CdCH2), 7.4-7.6 (m, 15H, Ph); 13C-
-H
{1H} NMR (150 MHz, CD2Cl2, 298 K) δ 15.7 (s, CH3), 66.2 (s,
3
2
OCH2), 94.4 (d, J P-C ) 6.7 Hz, dCH2), 129.5 (d, J P-C ) 10.5
Hz, ortho-Ph), 131.1 (d, J P-C ) 49.4 Hz, ipso-Ph), 131.7 (s,
para-Ph), 134.6 (d, J P-C ) 14.2 Hz, meta-Ph), 202.5 (d, J P-C
) 129.8 Hz, C-Au); 31P{1H} NMR (121.4 MHz, CD2Cl2, 298
K) δ 42.9 (s, PPh3); positive ion FAB-MS m/z 530 (M+). Anal.
Calcd for C22H22OPAu: C, 49.82; H, 4.18; O, 3.02. Found: C,
50.03; H, 4.25; O, 2.88.
1
3
2
Sp ectr oscop ic d a ta for 4: 1H NMR (600 MHz, CD2Cl2,
4
298 K) δ 2.73 (d, J cis
) 1.2 Hz, 1H, cis-CdCH2), 3.85 (s,
P-H
4
3H, OCH3), 4.17 (d, J trans
) 8.1 Hz, 1H, trans-CdCH2),
P-H
7.4-7.7 (m, 15H, Ph); 13C{1H} NMR (150 MHz, CD2Cl2, 298
3
K) δ 57.1 (d, J P-C ) 9.8 Hz, dCH2), 61.6 (s, OCH3), 129.6 (d,
Ack n ow led gm en t. We thank the NRF and the
Volkswagen-Stiftung for financial support. The mea-
surement of NMR spectra by the late H. S. C. Spies and
E. Marais and the collection of X-ray diffraction data
for 1 and 4 by J . Bacsa are gratefully acknowledged.
The work at Marburg was financially supported by the
DFG and the Fonds der Chemischen Industrie.
2J P-C ) 12.2 Hz, ortho-Ph), 130.0 (d, J P-C ) 53.7 Hz, ipso-
1
3
Ph), 131.9 (s, para-Ph), 134.5 (d, J P-C ) 14.6 Hz, meta-Ph),
2
185.3 (d, J P-C ) 124.5 Hz, C-Au), 200.1 (s, cis-CO), 204.1 (s,
trans-CO); 31P{1H} NMR (121.4 MHz, CD2Cl2, 298 K) δ 40.5
(s, PPh3); positive ion FAB-MS m/z 840 (M+); IR (cm-1, pentane
solution in NaCl cell) ν(CO) 1910 (s, A1(2)), 1924, 1936 (2 × s,
“E”), 1976 (w, B1), 2064 (w, A1(1)). Anal. Calcd for C26H20O6-
PWAu: C, 37.17; H, 2.40; O, 11.42. Found: C, 37.35; H, 2.62;
O, 11.53.
Su p p or tin g In for m a tion Ava ila ble: Crystallographic
data in CIF format for compounds 1 and 4. This material is
available free of charge via the Internet at http://pubs.acs.org.
Sp ectr oscop ic d a ta for 5: 1H NMR (600 MHz, CD2Cl2,
3
4
298 K) δ 1.25 (t, J H-H ) 7.1 Hz, 3H, CH3), 2.71 (d, J cis
)
P-H
1.7 Hz, 1H, cis-CdCH2), 4.13 (d, 4J trans P-H ) 8.0 Hz, 1H, trans-
CdCH2), 4.06 (dq, 2J H-H ) 9.5 Hz, 3J H-H ) 7.1 Hz, 1H, OCH2),
OM020048G