1-Metallacyclopropene complexes and η1-vinyl complexes containing the Cp*W(NO) fragment

Article abstract of DOI:10.1021/om990178y

The solid-state molecular structure of Cp*W(NO)(CH₂SiMe₃)(η²-CPhCH ₂) reveals that the vinyl ligand in this complex exists in a distorted form in the solid state that cannot be readily described by either of the classic η¹-vinyl or 1-metallacyclopropene limiting structures, by comparison to other crystallographically characterized vinyl complexes reported in the literature. However, the NMR parameters for the CPhCH₂ fragment in this complex are characteristic of those of a 1-metallacyclopropene unit. In addition to these studies, a series of vinyl-containing species of the general formulas Cp*W(NO)(η²-CPhCH₂)(X) and Cp*W-(NO)(η¹-CPh=CH₂)(LX) (X = Cl, OTf; LX = O₂CPh, NH^tBu, (PPh₃)(H)) has been prepared, and the solid-state metrical parameters and solution NMR spectroscopic properties of these complexes have been examined and compared to those of other vinyl-containing complexes reported in the literature. It has been found that the nature of the tungsten-vinyl interaction in these compounds is dependent upon the donor strength of the one-electron (1e) X or 3e LX donor ligands that are also present in the tungsten coordination sphere.

Full text of DOI:10.1021/om990178y

3128
Organometallics 1999, 18, 3128-3137
1-Meta lla cyclop r op en e Com p lexes a n d η1-Vin yl
Com p lexes Con ta in in g th e Cp *W(NO) F r a gm en t
Peter Legzdins,* Sean A. Lumb, and Steven J . Rettig†
Department of Chemistry, The University of British Columbia,
Vancouver, British Columbia, Canada V6T 1Z1
Received March 12, 1999
The solid-state molecular structure of Cp*W(NO)(CH2SiMe3)(η2-CPhCH2) reveals that the
vinyl ligand in this complex exists in a distorted form in the solid state that cannot be readily
described by either of the classic η1-vinyl or 1-metallacyclopropene limiting structures, by
comparison to other crystallographically characterized vinyl complexes reported in the
literature. However, the NMR parameters for the CPhCH2 fragment in this complex are
characteristic of those of a 1-metallacyclopropene unit. In addition to these studies, a series
of vinyl-containing species of the general formulas Cp*W(NO)(η2-CPhCH2)(X) and Cp*W-
(NO)(η1-CPhdCH2)(LX) (X ) Cl, OTf; LX ) O2CPh, NHtBu, (PPh3)(H)) has been prepared,
and the solid-state metrical parameters and solution NMR spectroscopic properties of these
complexes have been examined and compared to those of other vinyl-containing complexes
reported in the literature. It has been found that the nature of the tungsten-vinyl interaction
in these compounds is dependent upon the donor strength of the one-electron (1e) X or 3e
LX donor ligands that are also present in the tungsten coordination sphere.
In tr od u ction
methods. The solid-state characteristics of the CPhCH2
ligand in 1 have been investigated in greater detail, and
the results indicate that, while the W-(CPhCH2) bond-
ing interaction in this complex involves both carbon
nuclei of the vinyl moiety, the nature of the interaction
is not readily described by a limiting 1-metallacyclo-
propene bonding mode. The distorted nature of the
W-(η2-CPhCH2) interaction in 1 has prompted us to
undertake a more detailed investigation of the struc-
tural parameters of this fragment. With this goal in
mind, a series of vinyl-containing species of the general
formulas Cp*W(NO)(η2-CPhCH2)(X) and Cp*W(NO)(η1-
CPhCH2)(LX) (X ) Cl, OTf; LX ) O2CPh, NHtBu,
(PPh3)(H)) has been prepared, on the basis of the
presumption that the vinyl fragment will be manifested
in either the η1 or η2 form under the influence of other
one-electron (1e) X or 3e LX donor ligands present in
the tungsten coordination sphere. The solid-state metri-
cal parameters and solution NMR spectroscopic proper-
ties of these complexes have been examined and com-
pared to those of other η1-vinyl and 1-metallacyclopropene
complexes reported in the literature and help to shed
light on the W-vinyl interaction extant in 1. The results
of these investigations are presented in this paper.
We recently reported a unique C-H bond-activation
process effected during the thermal activation of an
tungsten nitrosyl vinyl complex.1 Specifically, the dual
C-H bond activation of either n-pentane or n-hexane
during the thermal decomposition of Cp*W(NO)(CH2-
SiMe3)(η2-CPhCH2) (1) to Cp*W(NO)(η2-PhCtCH) (A)
in the appropriate hydrocarbon solvent yields the novel
tungstenacycles Cp*W(NO)((η3-CHPh)CH2CHRCH2) (R
n
n
) Pr, Bu) (eq 1).1
(1)
The preliminary communication of this work de-
scribed the solid-state molecular structure of 1 as
determined by X-ray diffraction methods at ambient
temperature.1 The vinyl-H atoms were not located in
the difference map, and the structure showed large
anisotropic displacement parameters representing un-
resolved disorder, most notably in the atoms of the Cp*
ligand. The result was therefore a structure of relatively
low precision, affording a somewhat blurred image of
the molecule. Definite conclusions regarding the nature
of the W-vinyl interaction were difficult to make at that
time. Since then, the molecular structure of 1 has been
redetermined at 180 K by single-crystal X-ray diffraction
Resu lts a n d Discu ssion
A. Th e Vin yl-Tu n gsten In ter a ction in Cp *W-
(NO)(η2-CP h CH2)(CH2SiMe3) (1). The results of the
redetermination of the solid-state molecular structure
of 1 at 180 K are depicted in Figure 1. In contrast to
the findings of our earlier report, the vinyl H atoms
(H(16) and H(17)) were located during the refinement
of the structural data. In considering the W-vinyl
structural parameters, we note that some important
features that aid in the identification of an η1-vinyl or
* To whom correspondence should be addressed.
† Deceased October 27, 1998.
(1) Debad, J . D.; Legzdins, P.; Lumb, S. A.; Batchelor, R. J .; Einstein,
F. W. B. J . Am. Chem. Soc. 1995, 117, 3288.
10.1021/om990178y CCC: $18.00 © 1999 American Chemical Society
Publication on Web 07/17/1999

1-Metallacyclopropene and η1-Vinyl Complexes
Organometallics, Vol. 18, No. 16, 1999 3129
Å).3 In addition, this interatomic distance is substan-
tially shorter than the W-C single-bond distance ob-
served in η1-vinyl complexes of W (ca. 2.2 Å)4 and those
of typical 16e Cp*W(NO)(aryl)2 complexes (ca. 2.15 Å).5
Indeed, the W-C(11) distance is nearly identical with
the W-C contact in a W(η2-C(O)R) acyl fragment,5c
a
linkage previously described as containing substantial
alkylidene character.6
Certain structural parameters indicate that the
CPhCH2 fragment is bound to the tungsten atom in 1
in a distorted η2 fashion. For example, the W-C(11)-
C(12) bond angle is acute (97.5(4)°) yet remains larger
than the typical MdC1sC2 angles observed for other
1-metallacyclopropene complexes (70-85°).2 The long
W-C(12) contact (2.615(5) Å) is greater than a W-C2
single bond by a large margin (∼0.4 Å), and the C(11)-
C(12) bond length (1.342 (6) Å) is characteristic of a
double bond between these centers and is significantly
shorter than the distance observed for other 1-metal-
lacyclopropene complexes (∼1.45 Å). Further evidence
for a distortion in this fragment is given by the fact that
the vinyl plane embodied by C(12), H(17), and H(16) is
tilted by an angle of 25° with respect to the plane
defined by W(1), C(11), and C(13). Typical torsion angles
observed in the MdC1sC2sR fragment for other struc-
turally characterized 1-metallacyclopropene complexes
lie in the range of 70-90°.2a,d The bonding interaction
between W and C(12) in 1 is clearly less than that of a
W-C single bond. At best, the metal-vinyl interaction
observed in the solid-state molecular structure of 1 may
be described as a distorted 1-metallacyclopropene unit.
The reasons for such a distortion in the solid state are
unclear. There exist no unusual intermolecular close
contacts in the unit cell that could be responsible for
the distortion observed in the 1-metallacyclopropene
fragment.
An interesting structural feature that is inconsistent
with the assignment of a complete double bond to the
C(11)-C(12) link (despite the short bond length associ-
ated with this contact) is the angle between the W(1)-
C(11) vector and the plane of the phenyl substituent.
The two are nearly coplanar: the W(1)-C(11)-C(13)-
C(18) torsion angle is 177.9(3)°, strongly suggesting that
the phenyl ring is conjugated with the unsaturation in
the W(1)-C(11) link. The analogous torsion angle of
24.1(6)° defined by the C(12)-C(11)-C(13)-C(18) chain
indicates a reduction in the conjugation between the
phenyl ring and the vinyl CdC bond. On the basis of
F igu r e 1. Solid-state molecular structure of 1 with 50%
probability thermal ellipsoids depicted. Selected inter-
atomic distances (Å) and angles (deg): W(1)-N(1) ) 1.760-
(3), W(1)-Cp*(centroid) ) 2.04, N(1)-O(1) ) 1.237(4),
W(1)-C(19) ) 2.173(5), W(1)-C(11) ) 2.076(5), C(11)-
C(12) ) 1.342(6), C(11)-C(13) ) 1.470(7), W(1)-C(12) )
2.615(5), C(12)-H(17) ) 1.08(4), C(12)-H(16) ) 1.16(5);
W(1)-C(11)-C(12) ) 97.5(4), N(1)-W(1)-C(19) ) 96.0(2),
C(12)-C(11)-C(13) ) 123.0(4), N(1)-W(1)-C(11) ) 96.8-
(2), C(12)-W(1)-C(19) ) 89.8(2), C(11)-W-C(19) ) 114.9-
(2), W(1)-C(11)-C(13) ) 137.1(3), H(17)-C(12)-H(16) )
108.9(31), H(17)-C(12)-C(12) ) 128.1(20), H(16)-C(12)-
C(12) ) 122.9(25), C(11)-W(1)-Cp*(centroid) ) 113.3,
W(1)-C(6)-Si ) 117.7(4), W(1)-N(1)-O(1) ) 168.6(5).
1-metallacyclopropene unit in the M(C1(R)C2R2) frag-
ment (as depicted below) are the M-C1 and M-C2 bond
distances, the M-C1-C2 bond angle, the M-C1-R
angle, and the C1-C2 bond distance.
In the η1-vinyl fragment (M(η1-C1RdC2R2)), the M-C1
bond distance is typically that of a single M-C bond,
the M-C2 distance is greater than the sum of the van
der Waals radii of M and C2 (i.e. the two nuclei are
nonbonding), the M-C1-C2 and M-C1-R angles are
characteristically those of sp2-hybridized centers (ca.
120°), and the C1-C2 distance is typically that of a Cd
C bond (ca. 1.34 Å). In contrast, the M-C1 and M-C2
contacts in the 1-metallacyclopropene fragment (M(η2-
C1RC2R2)) are typically those of an MdC bond and an
M-C bond, respectively. The M-C1-C2 angle is con-
tracted (<90°) due to the M-C2 bonding interaction, and
the M-C1-R angle is typically expanded beyond 120°
in response to the distortion in the M-C1-C2 angle. The
C1-C2 distance is typically found to be intermediate
between a single and double C-C bond, ca. 1.45 Å.
(2) (a) Allen, S. R.; Beevor, R. G.; Green, M.; Norman, N. C.; Orpen,
A. G.; Williams, I. D. J . Chem. Soc., Dalton Trans. 1985, 435. (b)
Morrow, J . R.; Tonker, T. L.; Templeton, J . L. J . Am. Chem. Soc. 1985,
107, 6956. (c) Feng, S. G.; Gamble, A. S.; Templeton, J . L. Organome-
tallics 1989, 8, 2024. (d) Carfagna, C.; Carr, N.; Deeth, R. J .; Dossett,
S. J .; Green, M.; Mahon, M. F.; Vaughan, C. J . Chem. Soc., Dalton
Trans. 1996, 415. (e) Allen, S. R.; Green, M.; Orpen, A. G.; Williams,
I. D. J . Chem. Soc., Chem. Commun. 1982, 826. (f) Casey, C. P.; Brady,
J . T.; Boller, T. M.; Weinhold, F.; Hayashi, R. K. J . Am. Chem. Soc.
1998, 120, 12500.
(3) Nugent, W. A.; Mayer, J . M. Metal-Ligand Multiple Bonds;
Wiley: New York, 1988.
(4) van der Zeijden, A. A.; Bosch, H. W.; Berke, H. Organometallics
1992, 11, 563.
(5) (a) Debad, J . D.; Legzdins, P.; Batchelor, R. J .; Einstein, F. W.
B. Organometallics 1992, 11, 8. (b) Dryden, N. H.; Legzdins, P.; Rettig,
S. J .; Veltheer, J . E. Organometallics 1992, 11, 2583. (c) Debad, J . D.;
Legzdins, P.; Batchelor, R. J .; Einstein, W. B. Organometallics 1993,
12, 2094.
(6) (a) Rusik, C. A.; Collins, M. A.; Gamble, A. S.; Tonker, T. L.;
Templeton, J . L. J . Am. Chem. Soc. 1989, 111, 2550. (b) Feng, S. G.;
White, P. S.; Templeton, J . L. Organometallics 1993, 12, 2131.
The W-C(11) bond distance of 2.076 (5) Å in the
molecular structure of 1 borders on those typically found
for 1-metallacyclopropene MdC linkages (vide supra: M
) Mo, W, Re; 1.9-2.0 Å)2 and is comparable in magni-
tude to many WdCH(Ar) alkylidene bonds (1.86-2.15

3130 Organometallics, Vol. 18, No. 16, 1999
Ta ble 1. Nu m ber in g Sch em e, Yield , a n d An a lytica l Da ta for Com p lexes 1-7
Legzdins et al.
anal. found (calcd)
H
compd
compd no.
color (yield,a %)
C
N
Cp*W(NO)(η2-CPhCH2)(CH2SiMe3)
Cp*W(NO)(η2-CPhCH2)(Cl)
1
2
3
4
5
6
7
7-d 1
burgundy (72)
burgundy (74)
orange (83)
red (58)
brown (56)
brown (87)
gold (55)
49.30 (48.98)
44.56 (44.53)
51.87 (51.37)
37.94 (37.96)
b
49.43 (49.29)
60.68 (60.43)
c
6.29 (6.17)
4.49 (4.56)
4.78 (4.77)
3.70 (3.69)
2.52 (2.60)
2.89 (2.87)
2.60 (2.44)
2.30 (2.33)
Cp*W(NO)(η1-CPhdCH2)(O2CPh)
Cp*W(NO)(η2-CPhCH2)(OTf)
Cp*W(NO)(η1-CPhdCH2)(NHtBu)
Cp*W(NO)(η2-CHPhCH2N(C3H5)2)(Cl)
Cp*W(NO)(η1-CPhdCH2)(H)(PPh3)
Cp*W(NO)(η1-CPhdCH2)(D)(PPh3)
5.95 (5.69)
5.49 (5.75)
4.80 (4.79)
2.00 (1.96)
gold (51)
a
b
Isolated yield unless otherwise noted. Satisfactory analysis could not be obtained. c Not determined.
Ta ble 2. Ma ss Sp ectr oscop ic a n d IR Sp ectr a l Da ta
this information, assigning double-bond character to
both of the W(1)-C(11) and C(11)-C(12) linkages
results in an unrealistic hypervalent coordination ge-
ometry about C(11). Thus, a more reasonable represen-
tation consistent with the observed distortion of the
1-metallacyclopropene unit in the solid state involves
the delocalization of electron density throughout the
M-C(11)-C(12) fragment (depicted below). For reasons
of clarity and consistency, however, this fragment will
be represented throughout this report in the form of a
1-metallacyclopropene unit.
for Com p lexes 1-7
compd no.
MS (m/z)a
probe tempb (°C)
IR (Nujol, cm-1
)
1
2
3
540
489
576
180
150
120
1539 (νNO
1580 (νNO
1574 (νNO
)
)
)
1501 (νCO
)
4
601
120
1609 (νNO)
1355 (νSO
1237 (νCF
1588 (νNO
1581 (νNO
)
)
5
6
7
524
548c
715
200
150
150
)
)
)
)
)
1824 (νWH
1541 (νNO
1543 (νNO
1318 (νWD
7-d 1
716
150
)
a
Values for the highest intensity peak of the calculated isotopic
cluster (184W). Probe temperatures. c FAB+ mass spectrum.
b
In contrast to its solid-state metrical parameters, the
solution properties of the vinyl ligand in 1 are distinctly
characteristic of a 1-metallacyclopropene group.2 For
example, the C1 signal in the 13C NMR spectra of 1 is
manifested in the alkylidene region (δ 227.9). In addi-
tion, the C2 signal lies considerably upfield (83.1 ppm),
in the region normally associated with metalated, sp3-
or sp2-hybridized, σ-bound carbon nuclei in W nitrosyl
equiv) at low temperature affords good yields of air-
sensitive 2 after workup (eq 2). The identification of the
(2)
1
complexes.5c,7 The vinyl proton signals in the H NMR
spectrum of 1 likewise appear upfield at 3.88 and 3.56
ppm, near the region normally attributed to the tungsten-
bound, alkyl magnetic environment. In addition, the
magnitude of the one-bond Câ-H coupling constant
1-metallacyclopropene fragment in 2 is made on the
basis of solution NMR spectroscopic data and its solid-
state molecular structure (Figure 2). The 1H and 13C
NMR spectra for complex 2 in solution contain signals
analogous to those of 1 attributable to the methylene
protons (δ 4.43 and 4.25) and the carbenic C1 (δ 220.8)
and alkyl C2 (δ 83.6) nuclei of a 1-metallacyclopropene
unit. Although the methylene hydrogen atoms were not
located in the difference map during refinement of the
solid-state crystallographic data, the short W(1)-C(11)
contact (2.071(4) Å), the calculated W-C(12) distance
of 2.58 Å, the acute W(1)-C(11)-C(12) angle (96.4(3)°),
and the expanded W(1)-C(11)-C(13) angle (137.0(3)°)
are nearly identical with those of the vinyl ligand in the
structure of complex 1 and implicate the presence of a
1-metallacyclopropene unit in the molecular structure
of complex 2 analogous to that observed in 1. Similar
to the torsion angle in the solid-state structure of 1, the
respective W(1)-C(11)-C(13)-C(18) angle (170.0(3)°)
and the C(12)-C(11)-C(13)-C(18) angle (29.6(6) °) in
the solid-state structure of 2 suggests that the phenyl
substituent is conjugated both with the carbenic W-C(11)
link and the C(11)-C(12) link in the distorted 1-metal-
lacyclopropene fragment.
1
(1J CH ≈ J CH ≈ 146 Hz) is comparable to those deter-
a
b
mined for other 1-metallacyclopropene complexes of
W.2b,c,8
B. P r ep a r a tion of Cp *W(NO)(η2-CP h CH2)(X) a n d
Cp *W(NO)(η1-CP h dCH2)(LX) Com p lexes (X ) Cl,
OTf; LX ) η2-O2CP h , NHtBu , (P P h 3)(H), (P P h 3)(D))
a n d Th eir Solid -Sta te Str u ctu r a l a n d Solu tion
NMR Sp ect r oscop ic P r op er t ies. In the ensuing
discussion, the synthesis of each new vinyl complex will
be considered in turn, along with the relevant structural
and spectroscopic data that identify the tungsten-vinyl
interaction in each. Analytical data (Table 1), mass
spectrometric and infrared spectroscopic data (Table 2),
and 1H and 13C NMR spectroscopic data (Table 3) for
all compounds discussed in this paper and X-ray crys-
tallographic data (Table 4) for selected compounds are
collected in the appropriate tables.
(i) P r ep a r a tion of Cp *W(NO)(η2-CP h CH2)Cl (2).
A simple metathesis reaction between the parent dichlo-
ride Cp*W(NO)(Cl)2 and Mg(CPhdCH2)2‚x(dioxane) (1
(7) Legzdins, P.; Rettig, S. J .; Sa´nchez, L. J . Organometallics 1988,
7, 2394.
(8) Feng, S. G.; Templeton, J . L. Organometallics 1992, 11, 2168.

1-Metallacyclopropene and η1-Vinyl Complexes
Organometallics, Vol. 18, No. 16, 1999 3131
Ta ble 3. 1H a n d 13C NMR Sp ectr oscop ic Da ta for Com p lexes 1-7
compd no.
1b
1H NMRa (δ/ppm)
13C NMRa (δ/ppm)
227.9 (s, J WC ) 99 Hz, CPhCH2)
145.3 (s, Ph Cipso
3
4
1
7.87 (dd, J HH ) 8.0 Hz, J HH ) 1.2 Hz, 2H, Ph Hortho
)
3
7.29 (t, J HH ) 8.0 Hz, 2H, Ph Hmeta
)
)
)
3
1
7.11 (t, J HH ) 8.0 Hz, 1H, Ph Hpara
129.6 (d, J CH ) 157 Hz, Ph)
2
5
1
3.88 (dd, J HH ) 5.4 Hz, J HH ) 1.2 Hz, 1H, CPhCHaHb)
128.8 (d, J CH ) 157 Hz, Ph)
2
5
1
3.56 (dd, J HH ) 5.4 Hz, J HH ) 1.2 Hz, 1H, CPhCHaHb)
127.6 (d, J CH ) 157 Hz, Ph)
1.50 (s, 15H, C5Me5)
109.6 (s, C5Me5)
2
1
1
2
0.69 (d, J HH ) 12.6 Hz, 1H, CHaHbSiMe3)
83.1 (dd, J CH ≈ J CH ≈ 146 Hz, J WC ) 13 Hz, CPhCH2
a
b
1
0.59 (s, 9H, SiMe3)
35.5 (t, J CH ) 111 Hz, CH2SiMe3)
2
1
0.21 (d, J HH ) 12.6 Hz, 1H, CHaHbSiMe3)
9.5 (q, J CH ) 127 Hz, C5Me5)
1
3.4 (q, J CH ) 126 Hz, CH2SiMe3)
3
4
2
3
7.72 (dd, J HH ) 6.0 Hz, J HH ) 1.2 Hz, 2H, Ph Hortho
)
220.8 (CPhCH2)
3
7.22 (t, J HH ) 6.0 Hz, 2H, Ph Hmeta
)
)
142.7 (Ph Cipso)
129.6, 128.8, 127.6 (Ph)
3
7.13 (t, J HH ) 6.0 Hz, 1H, Ph Hpara
2
5
4.43 (dd, J HH ) 6.0 Hz, J HH ) 1.2 Hz, 1H, CPhCHaHb)
112.1 (C5Me5)
2
5
1
1
4.25 (dd, J HH ) 6.0 Hz, J HH ) 1.2 Hz, 1H, CPhCHaHb)
83.6 (dd, J CH ≈ J CH ≈ 151 Hz, CPhCH2)
a
b
1.51 (s, 15H, C5Me5)
9.5 (C5Me5)
3
8.07 (d, J HH ) 7.5 Hz, 2H, Ph Hortho
)
)
189.5 (PhCO2)
179.7 (CPhdCH2)
151.5 (Ph Cipso)
133.8, 130.1, 129.1, 128.4, 128.2, 127.3, 125.5 (Ar)
122.4 (CPhdCH2)
113.3 (C5Me5)
9.5 (C5Me5)
3
7.61 (d, J HH ) 7.8 Hz, 2H, Ph Hmeta
7.45 (pseudo-t, 4H, Ph Hmeta, Hortho
)
3
7.24 (t, J HH ) 6.2 Hz, 2H, Ph Hpara
)
)
3
7.12 (t, J HH ) 7.8 Hz, 1H, Ph Hpara
2
6.40 (d, J HH ) 2.1 Hz, 1H, CPhdCHaHb)
5.63 (d, J HH ) 2.1 Hz, 1H, CPhdCHaHb)
2
1.84 (s, 15H, C5Me5)
7.59 (m, 2H, Ph)
7.49 (m, 3H, Ph)
4
5
258.0 (CPhCH2)c
140.5 (Ph Cipso
129.1 (Ph Cortho
128.1, (Ph Cmeta
125.3 (Ph Cpara
)
2
2
4.99 (d, J HH ) 8.7 Hz, J WH ) 3.1 Hz, 1H, CPhCHaHb)
)
)
2
2
4.90 (br d, J HH ) 8.7 Hz, J WH ) 7.8 Hz, 1H, CPhCHaHb)
1.98 (s, 15H, C5Me5)
)
1
119.1 (q, J CF ) 315 Hz, CF3)
112.8 (C5Me5)
1
77.6 (br t, J CH ) 164 Hz, CPhCH2)
1
9.6 (q, J CH ) 126 Hz, CH2SiMe3)
7.77 (br, 1H, NH)
7.25 (m, 4H, Ph)
d185.1 (CPhdCH2)
150.1 (Ph Cipso
128.2 (Ph Cortho
127.7 (Ph Cmeta
126.3 (CPhdCH2)
125.6 (Ph Cpara
)
7.07 (m, 1H, Ph Hpara
)
)
2
6.21 (d, J HH ) 3.0 Hz, 1H, CPhdCHaHb)
)
2
5.51 (d, J HH ) 3.0 Hz, 1H, CPhdCHaHb)
1.80 (s, 15H, C5Me5)
)
t
1.39 (s, 9H, Bu)
111.6 (s, C5Me5)
33.4 (HNCMe3)
29.7 (HNCMe3)
10.0 (C5Me5)
3
6
7.69 (d, J HH ) 7.8 Hz, 2H, Ar Hortho
)
148.7 (Ph Cipso
133.6 (NCH2CHdCH2)
131.5 (Ph Cortho
131.1 (NCH2CHdCH2)
128.3 (Ph Cmeta
125.2 (Ph Cpara
)
3
3
7.29 (t, J HH ) 7.8 Hz, J HH ) 7.8 Hz, 2H, Ar Hmeta
)
3
7.03 (t, J HH ) 7.8 Hz, 1H, Ar Hpara
6.53 (m, 1H, NCH2CHdCH2)
)
)
5.70 (m, 1H, NCH2CHdCH2)
)
)
3
5.17 (d, J HH ) 10.2 Hz, 1H, NCH2CHdCH2)
4.90 (m, 3H, NCH2CHdCH2, WCHPhCH2)
121.6 (NCH2CHdCH2)
120.8 (NCH2CHdCH2)
111.3 (C5Me5)
3
4.29 (t, J HH ) 12 Hz, 1H, WCHPhCH2)
4.07 (m, 2H, NCH2CHdCH2)
3.26 (m, 1H, NCH2CHdCH2)
3.00 (m, 1H, NCH2CHdCH2)
2.74 (m, 1H, NCH2CHdCH2)
2.48 (m, 1H, NCH2CHdCH2)
1.59 (s, 15H, C5Me5)
64.6 (WCHPhCH2)
61.0 (NCH2CHdCH2)
60.8 (NCH2CHdCH2)
38.9 (WCHPhCH2)
10.1 (C5Me5)
3
2
7b,e
7.72 (br t, J HH ) 6.8 Hz, 6H, PPh3)
177.1 (d, J PC ) 21.8 Hz, CPhdCH2)
3
7.43 (d, J HH ) 7.2 Hz, 2H, Ph Hmeta
)
)
152.9 (Ph Cipso)
3
1
7.34 (t, J HH ) 7.5 Hz, 2H, Ph Hpara
137.2 (d, J PC ) 66 Hz, Ph Cipso)
3
7.08 (t, J HH ) 7.5 Hz, 1H, Ph Hpara
)
134.5, 134.2, 129.6, 129.3, 128.8, 128.2 (Ar)
125.3 (CPhdCH2)
6.98 (m, 9H, PPh3)
2
6.31 (d, J HH ) 3.0 Hz, 1H, CPhdCHaHb)
106.7 (C5Me5)
10.5 (C5Me5)
2
4.81 (d, J HH ) 3.0 Hz, 1H, CPhdCHaHb)
1.71 (s, 15H, C5Me5)
2
1.04 (d, J PH ) 96 Hz, WH)
b
3
7-d 1
7.72 (br t, J HH ) 6.8 Hz, 6H, PPh3)
f
3
7.43 (d, J HH ) 7.2 Hz, 2H, Ph Hmeta
)
)
3
7.34 (t, J HH ) 7.5 Hz, 2H, Ph Hpara
3
7.08 (t, J HH ) 7.5 Hz, 1H, Ph Hpara
)
6.98 (m, 9H, PPh3)
2
6.31 (d, J HH ) 3.0 Hz, 1H, CPhdCHaHb)
2
4.81 (d, J HH ) 3.0 Hz, 1H, CPhdCHaHb)
1.71 (s, 15H, C5Me5)
a
1H NMR spectra and 13C NMR spectra recorded in CDCl3 at room temperature unless otherwise noted. b 1H and 13C spectra recorded
in C6D6. c Spectrum recorded at -70 °C in CD2Cl2 solvent. Spectrum recorded in acetone-d6. e 31P NMR spectrum (ref. P(OMe)3): 27.1
d
ppm, d, J HP ) 93 Hz. f Not recorded.
2

3132 Organometallics, Vol. 18, No. 16, 1999
Ta ble 4. X-r a y Cr ysta llogr a p h ic Da ta for Com p lexes 1, 2, 6, a n d 7
Legzdins et al.
1
2
6
7
Crystal Data
empirical formula
cryst habit, color
cryst size (mm)
cryst syst
space group
V (Å3)
a (Å)
b (Å)
c (Å)
C
22H33NOSiW
C18H22ClNOW
C24H33ClN2OW
orange, irregular
0.20 × 0.40 × 0.40
monoclinic
C21/c (No.15)
4839(1)
29.017(4)
8.435(2)
19.812(5)
90
93.58(2)
90
8
1.605
49.1
C36H38NOPW
prism, burgundy
0.45 × 0.30 × 0.15
triclinic
prism, burgundy
0.12 × 0.30 × 0.40
triclinic
plate, yellow
0.04 × 0.15 × 0.40
monoclinic
P21/n (No. 14)
6271(1)
26.039(1)
8.902(2)
29.973(1))
90
115.479(3)
90
8
1.515
75.9
P1h (No. 2)
1162.0(2)
8.4119(7)
8.9053(9)
16.717(2)
89.106(4)
87.394(2)
68.2654(9)
2
P1h (No. 2)
890.6(2)
9.212(1)
14.235(2)
7.3792(8)
95.72(1)
107.674(8)
101.38(1)
2
R (deg)
â (deg)
γ (deg)
Z
calcd density (Mg/m3)
1.542
49.9
1.819
54.6
abs coeff (cm-1
)
F000
536
472
2320
2864
Data Collection and Refinement
scan type
ω-2θ
ω-2θ
ω-2θ
ω-2θ
scan width, deg
2θmax, deg
measd rflns
total
1.30 + 0.35 tan θ
1.10 + 0.35 tan θ
1.10 + 0.20 tan θ
60
70
55.0
155
10 476
8227
6038
13 897
unique
corrections
5220 (Rint ) 0.030)
Lorentz-polarizn abs
(transmissn factors:
0.4532-1.000)
7824 (Rint ) 0.034)
Lorentz-polarizn abs
(transmissn factors:
0.394-1.000)
5910 (Rint ) 0.059)
Lorentz-polarizn abs
(transmissn factors:
0.5399-1.000)
13 609 (Rint ) 0.064)
Lorentz-polarizn abs
(transmissn factors:
0.510-1.000), decay
(16.25% decline)
RF ) 0.048, RwF ) 0.044
2.09
final R indices
RF ) 0.030, RwF ) 0.026
1.68
1.89 and -2.46
RF ) 0.032, RwF ) 0.028
1.5
1.27 and - 1.26
RF ) 0.033, RwF ) 0.029
1.33
0.56 and -0.68
goodness of fit on F2
largest diff peak and
0.55 and -0.62
hole (Å-1
)
containing complexes. For example, when such an ab-
straction is conducted in MeCN utilizing AgBF4, MeCN-
solvated cations are typically isolated.9 Similarly,
treatment of Cp′M(NO)2Cl (M ) group 6 metal) with
AgBF4 in CH2Cl2 generates Cp′M(NO)2(η1-BF4) species
which can be used to prepare lactone and pyrone
complexes.10 Not surprisingly, metathesis of the chloride
in 2 by AgO2CPh results in the formation of benzoate-
containing 3, as depicted in eq 3.
(3)
This air-stable compound is isolated as orange needles
in good yields by crystallization from diethyl ether.
Signals for the vinyl protons in the H NMR spectrum
of this compound lie in the alkenyl region of the
spectrum at δ 6.40 and 5.63, considerably downfield of
the analogous signals for the methylene protons in
complexes 1 and 2. The vinyl C1 and C2 signals appear
1
F igu r e 2. Solid-state molecular structure of 2 with 50%
probability thermal ellipsoids depicted. Selected inter-
atomic distances (Å) and angles (deg): W(1)-N(1) ) 1.770-
(3), W(1)-Cp*(centroid) ) 2.04, W(1)-Cl(1) ) 2.375(1),
N(1)-O(1) ) 1.214(4), W(1)-C(11) ) 2.071(4), C(11)-C(12)
) 1.331(6), C(11)-C(13) ) 1.469(6); W(1)-C(11)-C(12) )
97.5(4), N(1)-W(1)-C(19) ) 96.0(2), C(12)-C(11)-C(13)
) 123.0(4), N(1)-W(1)-C(11) ) 96.4(3), W(1)-C(11)-C(13)
) 137.0(3), Cl(1)-W(1)-N(1) ) 99.3(1), Cl(1)-W(1)-Cp*-
(centroid) ) 112.8, Cl(1)-W(1)-C(11) ) 115.4(1), C(11)-
W-Cp*(centroid) ) 113.2, W(1)-N(1)-O(1) ) 170.0(3).
(9) (a) Legzdins, P.; Nurse, C. R. Inorg. Chem. 1982, 21, 3110. (b)
Chin, T. T.; Legzdins, P.; Trotter, J .; Yee, V. C. Organometallics 1992,
11, 913. (c) Legzdins, P.; Rettig, S. J .; Sayers, S. F. J . Am. Chem. Soc.
1994, 116, 12105. (d) Dryden, N. H.; Legzdins, P.; Sayers, S. F.; Trotter,
J .; Yee, V. C. Can. J . Chem. 1995, 73, 1035. (e) McCleverty, J . A.;
Murray, A. J . Transition Met. Chem. 1979, 4, 273.
(10) (a) Legzdins, P.; Martin, D. T. Organometallics 1983, 2, 1785.
(b) Legzdins, P.; Richter-Addo, G. B.; Einstein, F. W. B.; J ones, R. H.
Organometallics 1990, 9, 431. (c) Legzdins, P.; McNeil, W. S.; Vessey,
E. G.; Batchelor, R. J .; Einstein, F. W. B. Organometallics 1992, 11,
2718.
(ii) Reaction of Cp*W(NO)(η2-CP h CH2)Cl (2) with
AgX Sa lts (X ) O2CP h , OTf). Silver salts have long
been known to abstract halide ligands from Cp′M(NO)-

1-Metallacyclopropene and η1-Vinyl Complexes
Organometallics, Vol. 18, No. 16, 1999 3133
in the 13C NMR spectrum at δ 179.7 and 122.4, respec-
tively. These data taken together implicate an η1-vinyl
bonding interaction with the metal center in complex
3. Thus, the benzoate ligand must coordinate the
tungsten center in an η2 fashion in order to satisfy the
electronic saturation at the metal center. The solid-state
molecular structure of 3 determined by X-ray crystal-
lography confirms these proposals.11
By analogy to the conversion depicted in eq 2, the
reaction of 2 with 1 equiv of AgOTf affords triflate-
containing 4 in relatively good yields as a red crystalline
solid following workup and crystallization (eq 4). Con-
spectra of 4 remains uncertain, though variable-tem-
perature H NMR experiments reveal that this interac-
tion is temperature dependent.
1
(iii) R ea ct ion of 2 w it h E xcess tBu NH2 a n d
(C3H5)2NH. A common method used to introduce an
amide ligand into an organometallic complex involves
the reaction of excess amine with an organometallic
halide in an aminolysis reaction.14 Two equivalents of
amine is consumed in this reaction as the halide is
eliminated from the organometallic complex as the
counteranion in an ammonium salt. The reaction of
t
chloride-containing 2 with excess BuNH2 in this way
affords amide-containing 5 in moderate yields as yellow
microcrystals (eq 5).15 The amine H resonance of 5 is
(4)
(5)
siderable spectroscopic evidence exists in support of the
formulation of an inner-sphere triflate ligand in complex
4. It has been demonstrated previously that the coor-
dination mode of the triflate ligand may be identified
from the IR spectrum of the complex in question, the
highest energy absorption of the S-O link occurring in
the 1200-1280 cm-1 range for an ionic triflate group
or in the 1300-1380 cm-1 range of the IR spectrum for
a covalent triflate ligand.12 Bands attributable to the
1
observed as a broad singlet at 7.77 ppm in the H NMR
spectrum, and the tert-butyl group is evidenced by an
intense singlet that integrates for 9 H at 1.39 ppm.
Analogous to the NMR signals observed for benzoate-
containing 3, the chemical shifts of the 1H and 13C
resonances attributable to the respective vinyl protons
(6.21 and 5.51 ppm) and the vinyl carbon nuclei in 5
(185.1 and 126.3 ppm for C1 and C2, respectively) are
indicative of an η1-vinyl bonding interaction with W.
Interestingly, exposure of 2 to an excess of diallyl-
amine does not yield the corresponding secondary amide
vinyl complex. Instead, an unusual product of the
coupling of vinyl and amine fragments is formed in high
yield (complex 6, eq 6). The solid-state molecular
S-O stretch (1355 cm-1) and C-F stretch (1237 cm-1
)
of a covalently bound triflate ligand are evident in the
IR Nujol mull spectrum of complex 4. In addition, νNO
occurs at 1609 cm-1 in the region normally associated
with electroneutral organometallic nitrosyl complexes,13
a further indication of a covalently bound triflate ligand
in solid-state 4.
While it is conceivable that the covalent triflate ligand
could bind to W in a bidentate fashion to afford an 18e
complex analogous to benzoate-containing 3, the solu-
tion NMR data obtained for 4 are inconsistent with the
requisite η1-vinyl bonding interaction that would also
result. The signals attributable to the 1-metallacyclo-
propene C1 and C2 nuclei appear at 258.0 and 77.6 ppm,
respectively, in the 13C NMR spectrum of 4, and the
(6)
1
methylene proton signals appear in the H NMR spec-
trum for 4 at 4.90 and 4.99 ppm. Interestingly, the
upfield vinyl H signal is broadened and lower in
intensity than the downfield signal, suggestive of a
fluxional process or an interatomic interaction involving
one of the vinyl hydrogen atoms and either the metal
center or an atom of the triflate ligand. The broadened
signal attributable to the C2 resonance in the 13C{1H}
NMR spectrum of 4 exists as a broad pseudo-triplet
structure determined for this complex, depicted in
Figure 3, reveals that the chloride ligand remains in
the coordination sphere of tungsten. In addition, the
diallylamine unit is bound to W via a dative bond
(W(1)-N(1) ) 2.310(6) Å) and to the vinyl fragment
through a single N-C bond (N(1)-C(11) ) 1.491(8) Å)
as a component of an azametallacyclobutane ring.16 The
C(11)-C(12) contact (1.51(1) Å) and the W(1)-C(12)
1
(1J CH ≈ J CH ≈164 Hz) in the gate-decoupled 13C{1H}
a
b
NMR spectrum. On the basis of these NMR spectro-
scopic data it can be concluded that the vinyl fragment
in 4 is bound to tungsten as a component of a 1-metal-
lacyclopropene unit, as established for complexes 1 and
2. The nature of the fluxional process that broadens the
metallacyclopropene H and C signals in the NMR
(14) See: Legzdins, P.; Rettig, S. J .; Ross, K. J . Organometallics
1993, 12, 2103 and references therein.
(15) Satisfactory analysis could not be obtained for this complex.
It has been suggested by the microanalyst that the formation of
tungsten nitrides during combustion can lead to a reduction in the
observed carbon and nitrogen analyses.
(16) For another example of a W nitrosyl complex containing both
a W-N dative bond and C-N single bond, see: Debad, J . D.; Legzdins,
P.; Lumb, S. A.; Batchelor, R. J .; Einstein, F. W. B. Organometallics
1995, 14, 2543.
(11) Einstein, F. W. B.; Batchelor, R. J . Unpublished observations.
(12) (a) Lawrance, G. A. Chem. Rev. 1986, 86, 17. (b) Otieno, T.;
Rettig, S. J .; Thompson, R. J .; Trotter, J . Can. J . Chem. 1990, 68, 1901.
(13) Richter-Addo, G. B.; Legzdins, P. Metal Nitrosyls; Oxford
University Press: New York, 1992.

3134 Organometallics, Vol. 18, No. 16, 1999
Legzdins et al.
of 6 logically extends from the intermediacy of such a
tungsten carbene complex via amine-H tautomerization.
It is interesting that the reaction of 2 with diallyl-
amine does not yield the desired amide vinyl complex,
whereas the reaction of tert-butylamine with 2 does. It
is possible that the difference in the reactivity of tert-
butylamine and diallylamine with complex 2 could be
due to a difference in the steric profile of the two
reagents. The coordination environment about W in
complex 2 is considerably congested due to the presence
of the 1-metallacyclopropene unit, and as a result, its
accessibility to incoming reagents is presumably deter-
mined by the steric demands of the reagent. tert-
Butylamine is a primary amine and has a smaller steric
cross-section than does the secondary diallylamine
reagent. Thus, attack at the metal center by the
diallylamine reagent is hindered and the preferred site
of reactivity is at the kinetically more accessible met-
allacyclopropene unit.
(iv) Syn th esis a n d P r op er ties of Cp *W(NO)(η1-
CP h dCH2)(H)(P P h 3) (7). Complexes of the form Cp*M-
(NO)(R)2 (M ) Mo, W; R ) hydrocarbyl) are known to
be Lewis acidic at the metal center and undergo reac-
tions with a variety of electron-rich small molecules. In
particular, the reaction of Cp*W(NO)(CH2SiMe3)2 with
H2 has been investigated in great detail. At high
pressures of dihydrogen, bimetallic tetrahydride com-
plexes of tungsten are obtained in high yields following
the extrusion of 2 equiv of SiMe4.19 On the other hand,
the reaction of Cp*W(NO)(CH2SiMe3)2 with dihydrogen
at low pressures leads to the extrusion of only 1 equiv
of SiMe4.19 The hydride-containing species Cp*W(NO)-
(CH2SiMe3)(H) that is transiently generated undergoes
a variety of hydrotungstenation reactions in the pres-
ence of unsaturated substrates20 and can be trapped as
an 18e adduct by PMe3.19
F igu r e 3. Solid-state molecular structure of 6 with 50%
probability thermal ellipsoids depicted. Selected inter-
atomic distances (Å) and angles (deg): W(1)-N(2) ) 1.747-
(6), W(1)-Cp*(centroid) ) 2.06, N(2)-O(1) ) 1.227(7),
W(1)-N(1) ) 2.310(6), W(1)-Cl(1) ) 2.451(2), W(1)-C(12)
) 2.255(7), C(11)-C(12) ) 1.51(1), C(11)-N(1) ) 1.491(8);
W(1)-C(12)-C(11) ) 92.7(4), N(2)-W(1)-C(12) ) 92.4(3),
Cl(1)-W(1)-N(1) ) 79.2(2), Cl(1)-W(1)-N(2) ) 90.2(2),
C(11)-C(12)-C(119) ) 112.5(6), C(12)-C(11)-N(1) ) 103.6-
(6), N(1)-W(1)-C(12) ) 62.3(2), C(12)-W(1)-Cp*(centroid)
) 107.1, W(1)-N(2)-O(1) ) 168.4(7), N(1)-W(1)-Cp*-
(centroid) ) 139.7, N(2)-W(1)-Cp*(centroid) ) 117.6,
C(13)-N(1)-C(16) ) 106.9(6).
Sch em e 1
The analogous reaction of Cp*W(NO)(CH2SiMe3)(η2-
CPhdCH2) (1) with H2 in the presence of PPh3 affords
the air-sensitive, ether-soluble vinyl hydride 7 (eq 7).
distance (2.255(7) Å) are those of typical C-C and W-C
single bonds.17
(7)
A reasonable mechanistic pathway for this transfor-
mation is shown in Scheme 1. Attack at the methylene
carbon by diallylamine affords a zwitterionic ammonium
alkylidene complex which, upon tautomerization and
coordination of the pendant amine, leads to the forma-
tion of 6.
Support for this pathway is provided by Bergman’s
report of an isolable zwitterionic phosphonium carbene
complex:18
The presence of a hydride ligand in 7 is made obvious
by the medium-intensity W-H stretch evident in the
IR Nujol mull spectrum (1824 cm-1) and by the hydride
resonance in the 1H NMR spectrum (δ 1.04, 2J PH ) 96.1
Hz) of 7. These signals appear in the same regions of
their respective spectra as those of other phosphine-
containing nitrosyl hydride complexes of tungsten.21 The
deuteride-containing 7-d 1 may be prepared analogously
in the presence of D2 gas. Evidence for the presence of
a deuteride ligand in 7-d 1 is given by a W-D stretch in
its IR Nujol mull spectrum (1318 cm-1) that is shifted
Intermediate B depicted in Scheme 1 is an analogue to
this phosphonium carbene complex, and the formation
(19) Legzdins, P.; Martin, J . T.; Einstein, F. W. B.; J ones, R. H.
Organometallics 1987, 6, 1826.
(17) See, for example: Debad, J . D.; Legzdins, P.; Rettig, S. J .;
Veltheer, J . E. Organometallics 1993, 12, 2714.
(18) Huggins, J . M.; Bergman, R. G. J . Am. Chem. Soc. 1979, 101,
4410.
(20) Debad, J . D.; Legzdins, P.; Lumb, S. A.; Batchelor, R. J .;
Einstein, F. W. B. Organometallics 1995, 14, 2543.
(21) Martin, J . T. Ph.D. Thesis, The University of British Columbia,
1987.

1-Metallacyclopropene and η1-Vinyl Complexes
Organometallics, Vol. 18, No. 16, 1999 3135
Ta ble 5. 13C NMR Sp ectr oscop ic a n d Solid -Sta te Str u ctu r a l P a r a m eter s for th e Vin yl Liga n d in
1-Meta lla cyclop r op en e a n d η1-Vin yl Com p lexes
vinyl 13C NMR Data
vinyl ligand solid-state structural params
complex
δ(CR) δ(Câ)
d(M-CR), Å
d(M-Câ), Å
(M-CR-Câ), deg
1-Metallacyclopropene Complexes
(η5-C9H7)Mo(η2-C(SiMe3)CH2)(P(OMe)3
276.5b
260.6d
258.0f
227.9g
220.8f
28.9b
62.1d
77.6f
83.1g
83.6f
1.957(3)
1.94(1)
2.260(4)
2.32(1)
82.0(2)
85.5(4)
a
(Me2NCS2)3W(η2-CPhCPhCPhdCHPh)c
Cp*W(NO)(η2-CPhCH2)(OTf) (4)e
Cp*W(NO)(η2-CPhCH2)(CH2SiMe3) (1)e
Cp*W(NO)(η2-CPhCH2)(Cl) (2)e
2.076(5)
2.071(4)
2.615(5)
2.58h
97.5(4)
96.4(3)
η1-Vinyl Complexes
126.3f
Cp*W(NO)(η1-CPhdCH2)(NHtBu) (5)e
Cp*W(NO)(η1-CPhdCH2)(η2-O2CPh) (3)e
Cp*W(NO)(η1-CPhdCH2)(H)(PPh3) (7)e
185.1f
179.7f
177.1
122.4f
125.3b
2.21(1)
3.10h
120(1)
b
Reference 2e. Spectrum recorded in C6D6. c Reference 2c. Spectrum recorded in toluene-d8. e This work. f Spectrum recorded in
a
b
d
g
h
CDCl3. Spectrum recorded in CD2Cl2. Calculated distance.
F igu r e 5. Correlation of δ(C1) - δ(C2) and the solid-state
MdC1 distance.
The existence of a hydride ligand in complex 7 is
confirmed by its solid-state molecular structure (Figure
4), the hydride ligand having been located in the
difference map. The W(1)-H(1) distance (1.73 Å) and
W(1)-P(1) distance (2.519(3) Å) are comparable to those
of other structurally characterized phosphine-trapped
hydride complexes of the Cp*W(NO) fragment.19,21 The
vinyl ligand’s metrical parameters are clearly charac-
teristic of an η1-vinyl ligand. For example, the W(1)-
C(11) bond distance (2.21 Å) is that of a single W-C
bond. Likewise, the calculated W-C(12) distance of 3.10
Å is greater than the sum of the van der Waals radii of
the two nuclei. In addition, the W(1)-C(11)-C(12) bond
angle of 120(1)°, the W(1)-C(11)-C(13) angle of 123-
(1)°, and the C(11)-C(12) bond length of 1.33(2) Å are
indicative of sp2 hybridization at C(11) and double-bond
character in the C(11)-C(12) contact.
C. NMR Sp ectr oscop ic a n d Solid -Sta te Metr ica l
Cor r ela tion s for η1-Vin yl a n d 1-Meta lla cyclop r o-
p en e Com p lexes. A comparison of the NMR spectro-
scopic parameters of the metallacyclopropene units in
the complexes 1, 2, and 4 to those of known 1-metalla-
cyclopropene complexes and η1-vinyl complexes reveals
that the physical characteristics of the 1-metallacyclo-
propene units in 1, 2, and 4 lie intermediate between
those of the pure 1-metallacyclopropene and η1-vinyl
limiting forms (Table 5). In addition, graphical correla-
tions between the chemical shift difference of the two
carbon nuclei in the vinyl fragment, δ(C1) - δ(C2), and
the solid-state MdC1 distance (Figure 5) and MdC1s
C2 angle (Figure 6) also indicate that the physical
F igu r e 4. Solid-state molecular structure of 7 with 50%
probability thermal ellipsoids depicted. Selected inter-
atomic distances (Å) and angles (deg): W(1)-N(1) ) 1.66-
(2), W(1)-Cp*(centroid) ) 2.04, W(1)-P(1) ) 2.519(3),
W(1)-H(1) ) 1.73, N(1)-O(1) ) 1.28(2), W(1)-C(11) )
2.21(1), C(11)-C(12) ) 1.33(2), C(11)-C(13) ) 1.52(2);
P(1)-W(1)-N(1) ) 95.1(4), P(1)-W(1)-Cp*(centroid) )
141.4, N(1)-W(1)-Cp*(centroid) ) 118.7, W(1)-C(11)-
C(12) ) 120(1), C(12)-C(11)-C(13) ) 116(1), N(1)-W(1)-
C(11) ) 98.2(6), W(1)-C(11)-C(13) ) 123(1), C(11)-W(1)-
Cp*(centroid) ) 109.1, W(1)-N(1)-O(1) ) 166(1), P(1)-
W(1)-C(11) ) 81.5(3), P(1)-W(1)-H(1) ) 75.4, C(11)-
W(1)-H(1) ) 156.1, N(1)-W(1)-H(1) ) 78.4, H(1)-W(1)-
Cp*(centroid) ) 92.9.
relative to the W-H stretch in 7. The magnitude of this
value is in good agreement with the expected theoretical
value of 1290 cm-1 22 The signals in the 1H and 13C NMR
.
spectra attributable to the vinyl ligand in these com-
plexes are characteristic of an η1-vinyl ligand. The vinyl
protons resonate at 6.31 and 4.81 ppm, and the C1 and
C2 signals are identified in the olefinic region at 177.1
and 125.3 ppm, respectively.
(22) This calculation is based upon the assumption that the ground-
state vibrational frequency of an X-H bond will have the frequency ν
) 1/2π(k′/µ)1/2, based on the simple harmonic oscillator model, where
k′ is the force constant and µ ) reduced mass ) mXmH/(mX + mH). If
mX . mH, then µ ≈ mH. Making the same argument for an X-D bond,
and assuming that µH ≈ mH, µD ≈ mD, and k′H ≈ k′D, then νH/νD
)
1/2
(mD/mH
)
) 21/2. For a more detailed analysis, see: Connors, K. A.
Chemical Kinetics; VCH: New York, 1990.

3136 Organometallics, Vol. 18, No. 16, 1999
Legzdins et al.
Con clu sion s
Several 1-metallacyclopropene and η1-vinyl-contain-
ing complexes have been synthesized, and their solution
NMR spectroscopic and solid-state metrical parameters
have been investigated and compared to those of com-
plexes reported in the literature that also contain these
types of ligands. The results of these comparisons imply
that the vinyl ligands in complexes 1, 2, and 4 exist in
a form best described as a distorted 1-metallacyclopro-
pene unit. While the solution NMR spectroscopic prop-
erties observed for this fragment in complexes 1, 2, and
4 are more closely allied to those of previously reported
1-metallacyclopropene complexes, the solid-state struc-
tural properties of this fragment in complexes 1 and 2
are intermediate between those of other structurally
characterized 1-metallacyclopropene complexes and η1-
vinyl complexes reported in the literature.
F igu r e 6. Correlation of δ(C1) - δ(C2) and the solid-state
MdC1sC2 angle.
The donor ability of the CPhCH2 ligand in these
Cp*W(NO)-containing complexes can be assessed on the
basis of the bonding that is assumed in this fragment
in response to the presence of other X or LX ligands in
the tungsten coordination sphere. Pure σ-donor ligands
such as hydrocarbyls and weak π-donor ligands such
as chloride and triflate allow the stronger donor CPhCH2
fragment to assume the 1-metallacyclopropene form.
Strong donor ligands such as benzoate and amide force
the vinyl ligand into the η1 form to avoid an expansion
of the tungsten valence shell to 20e.
attributes of the vinyl fragment in 1 and 2 lie closer to,
yet less than, those of the pure 1-metallacylopropene
form. Clearly, a 1-metallacyclopropene fragment is
typified by signals in the 13C NMR spectrum at low and
high field attributable to the alkylidene and alkyl carbon
nuclei, respectively, whereas the C1 and C2 signals of
the η1-vinyl ligand appear mid-spectrum (120-190
ppm). The alkylidene carbon signals for the 1-metalla-
cyclopropene units in 1 and 2 are carbenic in character,
and the C2 signals appear upfield in the region associ-
ated with metalated paraffinic carbon resonances in
Cp*W(NO)-containing hydrocarbyl complexes.5c,14,23 The
tungsten-vinyl contacts and the metal-vinyl angles
determined for these complexes in the solid state are
intermediate between those typically observed for the
two limiting bonding forms. In particular, the long
W-Câ bonding interactions and the expanded W-C1-
C2 angles in 1 and 2 suggest that the W-C2 contact is
less than that of a W-C single bond in the solid-state
structures of these compounds.
The hapticity of the tungsten-vinyl interaction is
clearly dependent upon the donor ability of the other X
or LX ligands in the coordination sphere of tungsten (X
) CH2SiMe3, Cl, OTf; LX ) O2CPh, NHtBu, (PPh3)(H)).
Thus, conclusions regarding the relative electron-donor
ability of the vinyl ligand and a particular X or LX
ligand may be made on the basis of the nature of the
tungsten-vinyl interaction that is manifested in each
of these complexes. For example, each of the X ligands
in complexes 1, 2, and 4 possesses the capacity to func-
tion as a 3e LX ligand: the neosilyl ligand in 1 via an
R-C-H agostic interaction, the chloride ligand in 2 via
π-donation of p(lone pair) electron density, and the tri-
flate ligand in 4 via η2 coordination of two of the sul-
fonate oxygen atoms. However, the vinyl ligand is a
stronger electron donor than any of these X ligands, and
a distorted 3e 1-metallacyclopropene link is detected in
these compounds. In contrast, the respective benzoate
and amide ligands in complexes 3 and 5 are stronger
electron donors relative to the vinyl ligand. As a result,
the vinyl ligand is forced to assume the η1 bonding mode
to avoid an expansion of the tungsten valence shell to
20e.
Exp er im en ta l Section
Gen er a l Meth od s. All reactions and subsequent manipula-
tions were performed under anaerobic and anhydrous condi-
tions under either high vacuum or an atmosphere of dinitrogen
or argon. General procedures routinely employed in these
laboratories have been described in detail previously.24 The
organometallic reagents, namely Cp*W(NO)(Cl)2,4b Cp*W(NO)-
(CH2SiMe3)(η2-CPhCH2),1 and Mg(CPhdCH2)2‚x(dioxane)25 were
prepared according to published procedures. H2 (Linde, extra
dry) and D2 (CIL) were used as received. PPh3 (Aldrich) was
recrystallized from hexanes. tBuNH2 (Aldrich) and (C3H5)2NH
(Aldrich) were dried over CaH2 and vacuum-transferred as
required. AgO2CPh (Aldrich) and AgOTf (Aldrich) were stored
under dinitrogen in the glovebox and used as supplied without
further purification.
X-r a y Cr ysta llogr a p h ic Stu d ies. Data collection and
structure solution for complexes 1, 2, 6, and 7 was conducted
at the University of British Columbia. Measurements for
complex 1 were recorded on a Rigaku/ADSC diffractometer
equipped with
a CCD area detector. Data collection for
complexes 2, 6, and 7 were recorded on a Rigaku AFC 63
diffractometer. In all cases, the samples were irradiated with
graphite-monochromated Mo KR radiation (λ ) 0.710 69 Å).
All four structures were solved by heavy-atom Patterson
methods and expanded using Fourier techniques. For complex
1, all of the hydrogen atoms were located in the difference map,
though only the vinyl hydrogens (H(16) and H(17)) were
refined isotropically. The remainder were included in idealized
positions with d(C-H) ) 0.98 Å. Hydrogen atoms in the
structures determined for complexes 2, 6, and 7 were fixed in
calculated positions with d(C-H) ) 0.98 Å, except for the
hydride ligand in 7, which was fixed in the difference map
position and refined isotropically. Two crystallographically
independent molecules of 7 were identified in the crystal
(24) Legzdins, P.; Rettig, S. J .; Ross, K. J .; Batchelor, R. J .; Einstein,
F. W. B. Organometallics 1995, 14, 5579.
(25) Dryden, N. H.; Legzdins, P.; Batchelor, R. J .; Einstein, F. W.
B. Organometallics 1991, 10, 2077.
(23) (a) Dryden, N. H.; Legzdins, P.; Trotter, J . Yee, V. C.
Organometallics 1991, 10, 2857. (b) Dryden, N. H.; Legzdins, P.;
Lundmark, P. J . Organometallics 1993, 12, 2085.

1-Metallacyclopropene and η1-Vinyl Complexes
Organometallics, Vol. 18, No. 16, 1999 3137
lattice. The vinyl ligand in one of the two molecules shows
evidence of disorder; however, no attempt to model the disorder
was made. All calculations were performed using the teXsan26
crystallographic software package of Molecular Structure Corp.
P r ep a r a tion of Cp *W(NO)(η2-CP h CH2)(Cl) (2). Brown,
powdery Cp*W(NO)(Cl)2 (420 mg, 1 mmol) and white solid Mg-
(CPhdCH2)2‚x(dioxane) (105 mg, 1 equiv) were placed in a 50
mL Erlenmeyer flask in an inert-atmosphere glovebox. The
flask was cooled to ∼-100 °C in a liquid-N2-cooled cold well
over 20 min. THF (10 mL) was placed in a stoppered vial and
precooled to -35 °C in the glovebox freezer. The contents of
the THF vial were pipetted down the walls of the Erlenmeyer
flask submerged in the cold well, forming a solid puck of THF
on top of the solids in the base of the flask. The reaction flask
was then placed on a rotary evaporator. Warming the mixture
slowly to room temperature was accompanied by a color change
to a deep burgundy-black. After this mixture was stirred at
room temperature for 15 min, the THF was removed from the
final reaction mixture under vacuum to leave a burgundy-
brown solid. The solid was washed with diethyl ether (3 × 2
mL) and then dried under high vacuum for another 5 min.
Methylene chloride was added (7 mL), and the resulting
burgundy suspension was filtered through Celite. The filtrate
was concentrated, hexanes were added (3 mL), and the
burgundy solution was placed in the freezer (-35 °C) overnight
to induce the crystallization of pure 2 as burgundy blocks (280
mg). Concentration and cooling of the mother liquor to -35
°C overnight afforded a second crop of crystals (80 mg).
P r ep a r a tion of Cp *W(NO)(η1-CP h dCH2)(η2-O2CP h ) (3).
Burgundy 2 (244 mg, 0.5 mmol) was dissolved in CH2Cl2 (8
mL) in a 25-mL Erlenmeyer flask in an inert-atmosphere
glovebox. AgO2CPh (115 mg, 1 equiv) was placed in a stoppered
vial and suspended in CH2Cl2. The flask and vial were both
cooled to -35 °C in the glovebox freezer. After 15 min the two
vessels were removed from the freezer and the contents of the
vial were slowly added to the Erlenmeyer flask. As the mixture
was warmed to room temperature, a color change to dark
orange and the formation of a flocculent white precipitate
occurred. After being stirred at room temperature for 15 min,
the solvent was removed from the final reaction mixture under
vacuum to leave an orange residue. Diethyl ether (20 mL) was
added, and the resulting orange suspension was filtered
through Celite. The orange filtrate was concentrated, hexanes
(2 mL) were added, and the solution was placed in a freezer
(-35 °C) overnight to induce the crystallization of pure 3 as
orange needles (172 mg). Concentration and cooling of the
mother liquor to -35 °C overnight afforded a second crop of
crystals (66 mg).
P r ep a r a tion of Cp *W(NO)(η1-CP h dCH2)(NHtBu ) (5).
Crystalline 2 (244 mg, 0.5 mmol) was dissolved in THF (7 mL)
in a Schlenk tube. The tube was connected to a vacuum-
transfer bridge and cooled to -196 °C in a liquid-N2 bath.
tBuNH2 (excess) was vacuum-transferred onto the resulting
frozen solution. The mixture was warmed to room temperature
with stirring, whereupon a color change to brown occurred.
After being stirred at room temperature for 15 min, the solvent
was removed from the final reaction mixture under vacuum
to leave a yellow-brown residue. Methylene chloride/hexanes
(1:2, 5 mL) was added, and the resulting suspension was
filtered through Celite. The yellow filtrate was concentrated,
hexanes (3 mL) were added, and the solution was placed in a
freezer (-35 °C) overnight to induce the precipitation of 5 as
a yellow-brown, microcrystalline aggregate (148 mg).
P r ep a r a t ion of Cp *W(NO)(η2-CHP h CH2N(C3H5)2)(Cl)
(6). Complex 6 was prepared in a manner analogous to 5
except that excess diallylamine was vacuum-transferred onto
the solid solution of complex 2. An identical workup procedure
afforded large prismatic crystals of pure 6 (254 g) after the
brown filtrate was kept at -35 °C for 3 days in the glovebox
freezer.
P r ep a r a tion of Cp *W(NO)(η1-CP h dCH2)(H)(P P h 3) (7).
Cp*W(NO)(CPhdCH2)(CH2SiMe3) (135 mg, 0.25 mmol) and
PPh3 (66 mg, 1 equiv) were dissolved in hexanes (20 mL) in a
thick-walled glass reaction bomb. The bomb was connected to
a cylinder of H2 and frozen in a liquid-nitrogen bath. The bomb
was submitted to three freeze-pump-thaw cycles, whereupon
after the third evacuation dihydrogen (14 psig) was added. The
bomb was then maintained at 0 °C in a constant-temperature
bath for 4 days, during which time gold needles of 7 deposited
on the walls of the flask. After 4 days the H2 was removed
under vacuum and the mother liquor was decanted from the
crystals. The bomb was evacuated and left under vacuum for
1 h, after which time the gold crystals were isolated (58 mg).
The mother liquor was concentrated and cooled in a freezer
to induce further precipitation of 7 as an analytically pure
straw yellow powder (40 mg).
P r ep a r a tion of Cp *W(NO)(η1-CP h dCH2)(D)(P P h 3) (7-
d 1). Complex 7-d 1 was prepared in a manner analogous to
complex 7 except that D2 was employed in the place of H2. An
identical workup procedure afforded gold 7-d 1 (90 mg).
Ack n ow led gm en t. We are grateful to the Natural
Sciences and Engineering Research Council of Canada
for support of this work in the form of grants to P.L.
and a postgraduate fellowship to S.A.L. We also thank
The University of British Columbia for the award of a
University Graduate Fellowship to S.A.L.
P r ep a r a tion of Cp *W(NO)(η2-CP h CH2)(OTf) (4). Com-
plex 4 was prepared by the reaction of complex 2 (244 mg, 0.5
mmol) and AgOTf (129 mg, 1 equiv) in a manner analogous to
the preparation of complex 3, except that the AgOTf was
dissolved in diethyl ether (3 mL). An identical workup proce-
dure resulted in the precipitation of pure 4 as a red micro-
crystalline solid (175 mg).
Su p p or tin g In for m a tion Ava ila ble: Tables listing crys-
tallographic information, atomic coordinates and Beq values,
anisotropic thermal parameters, and intramolecular bond
distances, angles, and torsion angles. This material is available
free of charge via the Internet at http://pubs.acs.org.
(26) teXsan Crystal Structure Analysis Package; Molecular Struc-
ture Corp., The Woodlands, TX, 1985, 1992.
OM990178Y