Catalytic and selective ring expansion reactions of o-phenyl-substituted 2H-azaphosphirene tungsten complexes

Article abstract of DOI:10.1016/S0022-328X(01)01351-1

ortho-Phenyl-substituted ethoxy- and aminocarbene pentacarbonyltungsten complexes 2a-c and 3a-c are synthesized and the iatter are reacted with chloromethylenephosphane 4 in diethyl ether in the presence of triethylamine to yield the ortho-phenyl-substituted 2H-azaphosphirene complexes 6a-c via elimination of triethylammonium chloride; remarkable are the prolonged reaction times in the case of the methoxy- and dimethylamino-substituted complexes 6b,c. The 2H-azaphosphirene complexes 6a-c and 7d are reacted with benzonitrile in dichloromethane in the presence of ferrocenium hexafluorophosphate to furnish the 2H-1,2,4-diazaphosphole complexes 8a-d (8a: R = Me, 8b: R = OMe, 8c: R = NMe₂, 8d: R = H); the reaction course will be discussed. All complexes were unambiguously confirmed by NMR spectroscopy and elemental analysis and, additionally complexes 2b, 5 and 6b by X-ray analysis.

Full text of DOI:10.1016/S0022-328X(01)01351-1

Journal of Organometallic Chemistry 643–644 (2002) 253–264
www.elsevier.com/locate/jorganchem
Catalytic and selective ring expansion reactions of
o-phenyl-substituted 2H-azaphosphirene tungsten complexes
Christoph Neumann, Emanuel Ionescu, Udo Schiemann, Manuela Schlenker,
Maren Bode, Frank Ruthe, Peter G. Jones, Rainer Streubel *
Institut fu¨r Anorganische und Analytische Chemie der Technischen Uni6ersita¨t Braunschweig, Postfach 3329, 38023 Braunschweig, Germany
Received 4 July 2001; accepted 31 August 2001
Dedicated to Professor Franc¸ois Mathey on the occasion of his 60th birthday
Abstract
ortho-Phenyl-substituted ethoxy- and aminocarbene pentacarbonyltungsten complexes 2a–c and 3a–c are synthesized and the
latter are reacted with chloromethylenephosphane 4 in diethyl ether in the presence of triethylamine to yield the ortho-phenyl-sub-
stituted 2H-azaphosphirene complexes 6a–c via elimination of triethylammonium chloride; remarkable are the prolonged reaction
times in the case of the methoxy- and dimethylamino-substituted complexes 6b,c. The 2H-azaphosphirene complexes 6a–c and 7d
are reacted with benzonitrile in dichloromethane in the presence of ferrocenium hexafluorophosphate to furnish the 2H-1,2,4-di-
azaphosphole complexes 8a–d (8a: R=Me, 8b: R=OMe, 8c: R=NMe2, 8d: R=H); the reaction course will be discussed. All
complexes were unambiguously confirmed by NMR spectroscopy and elemental analysis and, additionally complexes 2b, 5 and
6b by X-ray analysis. © 2002 Elsevier Science B.V. All rights reserved.
Keywords: Azaphosphirene complexes; Carbene complexes; Diazaphospholes; Ring formation; Phosphorus; Tungsten
1. Introduction
a weakly exothermic process according to DFT-calcula-
tions [11] (Scheme 1).
Transition-metal promoted synthesis of P-heterocy-
cles has attracted attention over the years, because of
the frequently outstanding reaction selectivities and
product yields [1]. Recently, we demonstrated the wide-
spread applicability of 2H-azaphosphirene metal com-
plexes I [2] in heterocyclic ligand synthesis using ring
cleavage [3] and ring expansion reactions. In the latter
case intermediately formed nitrilium phosphanylid
metal complexes II were trapped and thus proved to be
the reactive species [4,5]. By using this new building
block in [3+2]-cycloaddition reactions we gained ac-
cess to a variety of five-membered P-heterocycle com-
plexes [6–8]. More generally, the formation of nitrilium
phosphanylid metal complexes II can be achieved via
end-on [1,1]-addition reactions of terminal phos-
phanediyl complexes III [9,10] to carbonitriles, which is
More recently, we presented a novel application of
2H-azaphosphirene complexes I in heterocycle synthe-
sis through PꢀN bond-selective ring expansion reac-
tions, which do not proceed via the intermediates II
and/or III and which have to be induced by catalytical
amounts of typical one-electron oxidants such as tetra-
cyanoethylene [12] and/or ferrocenium hexafluorophos-
phate [13]. Besides the presence of such oxidants in
these reactions, the following factors are important: (1)
polar solvents such as dichloromethane or carbonitriles;
(2) p-systems that additionally possess a lone pair at
one terminal atom; and (3) the nucleophiles should
Scheme 1. 2H-Azaphosphirene complexes I as precursors for nitril-
ium phosphanylid complexes II and terminal phosphanediyl com-
plexes III (M=Cr, Mo, W; R, R%=organic substituents).
* Corresponding author. Tel.: +49-531-3917350; fax: +49-531-
3915387.
E-mail address: r.streubel@tu-bs.de (R. Streubel).
0022-328X/02/$ - see front matter © 2002 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)01351-1

254
C. Neumann et al. / Journal of Organometallic Chemistry 643–644 (2002) 253–264
Table 1
Selected 13C-NMR data a of carbene complexes 2a, 2b [16], 2c and
3a–c
Compounds l-13C ([W]ꢁC) l-13C (cis-CO) l-13
C
(trans-CO)
Scheme 2. Assumed formation of 2H-azaphosphirene complex radical
cations IV from 2H-azaphosphirene complexes I via one-electron
oxidation reaction in solution (M=Cr, Mo, W; R, R%=organic
substituents).
2a
2b [16]
2c
3a
3b
329.4
325.3
330.4
272.4
264.5
268.8
196.6
197.3
196.4
197.9
198.4
198.2
203.0
205.4
203.6
203.7
203.9
204.1
3c
a CDCl3.
we report synthesis and catalytic reactions of such
2H-azaphosphirene complexes with benzonitrile and
ferrocenium hexafluorophosphate.
2. Results and discussion
2.1. Synthesis and NMR spectroscopic data of
ortho-phenyl-substituted aminocarbene complexes 2a–c
and 3a–c
Scheme 3. Synthesis of ethoxy- and aminocarbene complexes 2a–c
and 3a–c.
The ortho-phenyl-substituted aminocarbene tungsten
complexes were synthesized analogously to the proce-
dure described by Fischer and Kollmeier (Scheme 3)
[15]. The reactions proceeded smoothly for the carbene
complexes 3a,b. Only in the case of the ethoxycarbene
complex 2c [16], slight decomposition was observed in
solution, thus leading to reduced yields of complex 3c.
The molecular structure of complex 2b, obtained by
single crystal X-ray analysis [17], shows a Z-configu-
rated CꢀO unit with otherwise common structural fea-
tures and parameters (Fig. 1) [18].
The 13C-NMR spectroscopic data of the carbene
atoms of complexes 2a–c and 3a–c were observed in
the typical range [18] of such compounds (Table 1).
Apart from their E,Z-isomerism, which has been al-
ready recognized and investigated in detail for complex
2b [16] and related complexes, complexes 2a,b displayed
no unusual NMR data. Complexes 3a,c showed lowfi-
eld-shifts of the carbene carbon atoms of ca. 8–14 ppm
as compared to the corresponding para-phenyl-substi-
tuted aminocarbene complexes [19], whereas for com-
plex 3b no significant deviation of the chemical shift
value was observed.
Fig. 1. 31P-NMR resonances of 6a–c and 7a–c (CDCl3) (c=0.25 mol
l
−1).
possess substituents that are not bulky. All aspects
taken together indicate primary formation and subse-
quent reaction of a 2H-azaphosphirene complex radical
cation IV (Scheme 2), although we have so far not
succeeded in obtaining evidence of this by spectroscopic
means. In order to obtain more information about
stereoelectronic factors that might affect the reaction
course, we decided to synthesize ortho-phenyl-substi-
tuted 2H-azaphosphirene tungsten complexes using our
metal carbene complex rearrangement route [14]. Here,
2.2. Synthesis and spectroscopic data of
ortho-phenyl-substituted 2H-azaphosphirene complexes
6a–c
The 2H-azaphosphirene complexes 6a–c were ob-
tained by reacting the aminocarbene complexes 3a–c
with [bis(trimethylsilyl)methylene]chlorophosphane (4)

C. Neumann et al. / Journal of Organometallic Chemistry 643–644 (2002) 253–264
255
Table 2
Selected NMR data a of 2H-azaphosphirene complexes 6a–c and 7d [19]
Compounds
l-31P (1J(W, P))
l-13C (PCN) (1+2J(P, C))
l-13C (cis-CO) (2J(P, C))
l-13C (trans-CO) (2J(P, C))
6a
6b
6c
7d [19]
−128.3 (293.2)
−110.7 (295.2)
−125.1 (292.8)
−111.0 (293.8)
191.9 b
196.4 (9.0)
196.1 (8.7)
196.6 (8.8)
196.4 (8.8)
197.7 (35.8)
198.5 (35.9)
198.4 (35.0)
197.9 (36.1)
189.6 b
187.7 (2.1)
192.4 (1.7)
a CDCl3.
b Not resolved.
[20] in diethyl ether in the presence of triethylamine
(Scheme 4). Exclusively in the case of complex 3a, the
reaction proceeded smoothly to the 2H-azaphosphirene
complex 6a. In the cases of complexes 3b and 3c longer
reaction times than those of the para-phenyl-substituted
2H-azaphosphirene complexes were observed [19]. Fur-
thermore, the final products exhibited an enhanced
reactivity towards triethylammonium chloride at ambi-
ent temperature, thus leading to a cleavage of the
three-membered ring, whereby the phosphorus-contain-
ing product was identified by its typical 31P-NMR
resonance [19]. The ring cleavage could be significantly
suppressed by using acetonitrile as solvent and lower
temperatures, thus also diminishing the reaction times
for 6b,c. It was also remarkable that the intermediately
formed ortho-methoxy-substituted dinuclear bis-car-
bene complex 5 displayed a longer lifetime than the
corresponding para-substituted complex [19]. We were
thus enabled to isolate complex 5 and to get structural
information via an X-ray analysis of suitable single
crystals of 5 (Fig. 2, Table 3 and Table 6) [17]. Complex
5 displayed the typical E,E-configuration at the CꢀN
bonds, which had already been observed for related
complexes [19]. In general, CꢀN bonds of aminocarbene
complexes have enhanced bond orders, thus leading to
E,Z-isomeric forms [18].
pendent molecules, revealed that the methoxy-
substituent is on the phosphorus side (Fig. 5, Tables 3
and 7) rather than the nitrogen side of the 2H-azaphos-
phirene ring [21]. This outcome was surprising with
respect to steric repulsion between the methoxy group,
on one hand, and the pentacarbonyltungsten fragment
and the bis(trimethylsilyl)methyl group, on the other
hand, which was expected to be significant. The inter-
planar angle between the two ring systems of 12.3°
(19.8°) would enable an interaction between the
methoxy oxygen atom and the phosphorus atom. Fur-
,
thermore, the C14ꢀC19ꢀO6 angle of 116.0(2) A (115.5
,
A) deviates slightly from the expected 120° value and
would also be consistent with such an interaction, but
,
,
the OꢀP distance of 3.576(2) A (3.486 A) is greater than
the sum of the oxygen–phosphorus van der Waals-radii
,
of 3.4 A. The other structural features of complex 6b
are normal for aryl-substituted 2H-azaphosphirene
complexes.
From the NMR spectroscopic data of the 2H-aza-
phosphirene complexes 6a–c, the phosphorus reso-
nances are the most significant (Table 2), whereby a
very surprising observation was made for complex 6b.
Whereas, the 31P resonances of 6a,c appeared signifi-
cantly highfield-shifted as compared to the correspond-
ing para-phenyl-substituted complexes 7a–c [19] (Fig.
3), this was not the case for complex 6b. In contrast, the
31P resonance of complex 7c showed a highfield-shift as
compared to complex 6b. Furthermore, we, at first
thought that the solvent dependence of the phospho-
rus–tungsten coupling constant magnitude of 6b was
exceptionally great, but this behavior was strictly paral-
leled by complex 7b, albeit the magnitude was found to
be generally higher for complex 6b (Fig. 4). The origins
of these special effects of the ortho-bonded methoxy
group are not yet understood.
The X-ray structure analysis [17] of 2H-azaphos-
phirene complex 6b, which crystallizes with two inde-
Scheme 4. Synthesis of dinuclear bis-carbene complex 5 and 2H-aza-
phosphirene complexes 6a–c.

256
C. Neumann et al. / Journal of Organometallic Chemistry 643–644 (2002) 253–264
Fig. 2. Tungsten–phosphorus coupling constants of 6b and 7d in different solvents (CDCl3) (c=0.25 mol l−1).
the C3 atoms in 8a–c are more shielded than in 8d and
2.3. Synthesis and spectroscopic data of
ortho-phenyl-substituted 2H-1,2,4-diazaphosphole
complexes 8a–c
display greater variations. The 31P-NMR spectra
showed also some substituent effects on the resonances,
although not as expected for electron-donating groups.
2H-Azaphosphirene complexes 6a–c and 7d [19] re-
acted with benzonitrile (two equivalents) in
dichloromethane in the presence of ferrocenium he-
xafluorophosphate (0.2 equivalents) to 2H-1,2,4-diaza-
phosphole complexes 8a–c and 8d [6] (Scheme 5),
which were isolated in moderate to good yields by
column chromatography at low temperature. Apart
from ferrocene, which was isolated in ca. 10% yield,
and the hexafluorophosphate, which was easily iden-
tified by its 31P-NMR data, we could neither detect nor
identify the cation formed in this reaction. The reaction
rate decreased significantly from complex 7d\6a\
6b\6c (0.8, 1, 12 h, 5 days; ca. 20% conversion of 6c),
which corresponds to the increase in electron donor
abilities of the aryl substituents [22] of the 2H-azaphos-
phirene complexes along the series 6c\6b\6a\7d.
Because complex 6c showed almost no reaction under
these conditions, we used neat benzonitrile as solvent.
But even under these conditions the reaction was slow
(5 days). Furthermore, only in the case of complex 6c
did we observe a reactive intermediate by 31P-NMR
2.3.1. Conclusions
Two interpretations of our findings presented are
plausible, which depend on the charge partitioning
within the 2H-azaphosphirene complex radical cations
IV — which are still undetected and which are as-
sumed to be produced via one-electron oxidation with
the ferrocenium salt (Scheme 2). If the charge is mostly
localized on the phosphorus atom then intramolecular
donor adducts of type V might be reactive intermedi-
ates during the ring expansion (Fig. 6). The adduct
formation would significantly decrease the electrophilic-
ity of the phosphorus atom of the 2H-azaphosphirene
complexes in the case of complexes 6b,c, and, in conse-
quence, slow down the reaction rate. As an alternative,
if the charge is mostly localized on the tungsten atom,
intramolecular chelate complexes VI, via coordination
of the methoxy- or dimethylamino group to the tung-
sten complex fragment, might be formed intermedi-
ately, thus also pushing electron density into the
system. A related bonding situation concerning the
phosphorus atom in V has been proposed to occur in
reactions of 1H-phosphirene complexes with nucle-
ophiles [23].
1
spectroscopy (186.5 ppm, J(W, P)=305.5 Hz), which
unfortunately could not be isolated. Some characteristic
NMR data of complexes 8a–c and 8d are collected in
Table 4. Whereas, the 13C-NMR chemical shifts of the
C5 atom resonances are stuningly invariant at 169 ppm,
Currently, further investigations are under way,
which aim at the elucidation of the reaction mechanism.

C. Neumann et al. / Journal of Organometallic Chemistry 643–644 (2002) 253–264
257
3. Experimental
Table 5
,
Bond lengths (A) and angles (°) for complex 2b
3.1. General procedures
Bond lengths
WꢀC(1)
WꢀC(3)
WꢀC(2)
WꢀC(4)
2.0199(73)
2.0206(72)
2.0301(72)
2.0393(74)
2.0734(75)
2.1724(74)
1.1509(84)
1.1584(86)
1.1500(82)
1.1418(86)
1.1339(84)
1.3106(84)
1.5114(96)
1.3719(114)
1.3987(106)
1.3671(90)
1.3762(107)
1.3867(128)
1.3841(127)
1.3979(120)
1.4207(96)
1.4633(86)
1.4931(120)
All reactions and manipulations were carried out
under an atmosphere of deoxygenated dry nitrogen,
WꢀC(5)
WꢀC(6)
Table 3
Crystal data and structure refinement of complexes 2b, 5 and 6b
C(1)ꢀO(1)
C(2)ꢀO(2)
C(3)ꢀO(3)
C(4)ꢀO(4)
C(5)ꢀO(5)
C(6)ꢀO(7)
C(6)ꢀC(7)
C(7)ꢀC(12)
C(7)ꢀC(8)
C(8)ꢀO(6)
C(8)ꢀC(9)
C(9)ꢀC(10)
C(10)ꢀC(11)
C(11)ꢀC(12)
O(6)ꢀC(13)
O(7)ꢀC(14)
C(14)ꢀC(15)
Complex
2b
5
6b
Empirical
formula
Mr
Crystal system
Crystal habbit
Space group
T (K)
Unit cell
dimensions
a (pm)
C15H12O7W C33H35N2O12
-
C20H26NO6-
PSi2W
647.42
PSi2W2
1106.48
488.10
Monoclinic
Red block
P21
Monoclinic
Orange tablet Colorless tablet
P21/n
173(2)
Triclinic
(
P1
143(2)
133(2)
706.9(3)
1006.9(3)
1137.5(4)
90
104.06(4)
90
0.7854(4)
2
2.064
7.387
0.71–0.85
464
0.7×0.4
×0.4
50
1137.1(3)
1835.1(2)
1960.9(3)
90
93.992(18)
90
4.0818(12)
4
1.801
5.788
0.51–0.99
2136
0.40×0.25
×0.08
50
1240.007(8)
1414.34(11)
1483.74(11)
85.421(3)
86.244(3)
87.831(3)
2.5870(3)
4
1.662
4.653
0.61–0.86
1272
0.24×0.17
×0.12
b (pm)
c (pm)
h (°)
i (°)
k (°)
Bond angles
V (nm3)
Z
C(1)ꢀWꢀC(3)
C(1)ꢀWꢀC(2)
C(3)ꢀWꢀC(2)
C(1)ꢀWꢀC(4)
C(3)ꢀWꢀC(4)
C(2)ꢀWꢀC(4)
C(1)ꢀWꢀC(5)
C(3)ꢀWꢀC(5)
C(2)ꢀWꢀC(5)
C(4)ꢀWꢀC(5)
C(1)ꢀWꢀC(6)
C(3)ꢀWꢀC(6)
C(2)ꢀWꢀC(6)
C(4)ꢀWꢀC(6)
C(5)ꢀWꢀC(6)
O(1)ꢀC(1)ꢀW
O(2)ꢀC(2)ꢀW
O(3)ꢀC(3)ꢀW
O(4)ꢀC(4)ꢀW
O(5)ꢀC(5)ꢀW
O(7)ꢀC(6)ꢀC(7)
O(7)ꢀC(6)ꢀW
C(7)ꢀC(6)ꢀW
C(12)ꢀC(7)ꢀC(8)
C(12)ꢀC(7)ꢀC(6)
C(8)ꢀC(7)ꢀC(6)
O(6)ꢀC(8)ꢀC(9)
O(6)ꢀC(8)ꢀC(7)
C(9)ꢀC(8)ꢀC(7)
C(8)ꢀC(9)ꢀC(10)
C(11)ꢀC(10)ꢀC(9)
C(10)ꢀC(11)ꢀC(12)
C(7)ꢀC(12)ꢀC(11)
C(8)ꢀO(6)ꢀC(13)
C(6)ꢀO(7)ꢀC(14)
O(7)ꢀC(14)ꢀC(15)
86.7(3)
86.4(3)
173.1(3)
89.8(3)
88.2(3)
91.3(3)
90.2(3)
88.9(3)
91.6(3)
177.1(3)
174.7(3)
96.5(2)
90.4(3)
94.5(3)
Dcalc (mg m−3
)
v (mm−1
)
Transmissions
F(000)
Crystal size
(mm)
2qmax
60
Reflections
Measured
Unique
3001
2771
0.0282
147
210
7565
7182
0.028
485
59 025
15 086
0.0595
573
Rint
Parameters
Restraints
Flack-
parameter
wR (F2, all
reflections)
R [I\2|(I)]
S
35
45
85.6(3)
−0.03(2)
179.4(7)
175.4(7)
176.1(6)
177.6(7)
179.1(6)
106.5(6)
133.7(5)
119.8(4)
120.4(7)
122.3(7)
117.4(7)
125.2(7)
115.0(6)
119.7(7)
120.1(8)
120.2(7)
119.7(8)
119.8(8)
117.7(6)
121.3(6)
108.2(7)
0.0704
0.0533
0.0561
0.0280
1.031
1061
0.0540
0.950
1631
0.0305
0.875
695
Max Dz
(e nm−3
)
Table 4
Selected NMR data a of 2H-1,4,2-diazaphosphole complexes 8a–d
Compounds l-31
P
l-13C3
l-13C5
(
2+3J(P, C))
(1J(W, P))
(1J(P, C))
8a
8b
8c
8d
115.8 (229.2)
111.7 (222.0)
114.4 (236.7)
110.6 (227.9)
198.3 (22.6)
196.5 (24.5)
198.2 (22.1)
202.3 (22.9)
169.0 (4.3)
168.0 (4.3)
169.3 (4.6)
169.5 (5.1)
a CDCl3.

258
C. Neumann et al. / Journal of Organometallic Chemistry 643–644 (2002) 253–264
Table 6 (Continued)
Table 6
,
Bond lengths (A) and angles (°) for complex 5
C(3)ꢀW(1)ꢀC(2)
C(5)ꢀW(1)ꢀC(2)
C(4)ꢀW(1)ꢀC(18)
C(1)ꢀW(1)ꢀC(18)
C(3)ꢀW(1)ꢀC(18)
C(5)ꢀW(1)ꢀC(18)
C(2)ꢀW(1)ꢀC(18)
C(6)ꢀW(2)ꢀC(7)
C(6)ꢀW(2)ꢀC(8)
C(7)ꢀW(2)ꢀC(8)
C(6)ꢀW(2)ꢀC(10)
C(7)ꢀW(2)ꢀC(10)
C(8)ꢀW(2)ꢀC(10)
C(6)ꢀW(2)ꢀC(9)
C(7)ꢀW(2)ꢀC(9)
C(8)ꢀW(2)ꢀC(9)
C(10)ꢀW(2)ꢀC(9)
C(6)ꢀW(2)ꢀC(26)
C(7)ꢀW(2)ꢀC(26)
C(8)ꢀW(2)ꢀC(26)
C(10)ꢀW(2)ꢀC(26)
C(9)ꢀW(2)ꢀC(26)
N(1)ꢀPꢀN(2)
92.8(2)
90.2(2)
95.6(2)
178.0(2)
90.9(2)
88.0(2)
87.9(2)
88.0(3)
89.8(3)
88.9(3)
91.7(3)
89.8(3)
178.0(2)
85.3(3)
172.9(3)
88.7(3)
92.7(3)
174.8(2)
97.2(2)
90.5(2)
88.1(2)
Bond lengths
W(1)ꢀC(4)
W(1)ꢀC(1)
W(1)ꢀC(3)
W(1)ꢀC(5)
W(1)ꢀC(2)
W(1)ꢀC(18)
W(2)ꢀC(6)
W(2)ꢀC(7)
W(2)ꢀC(8)
W(2)ꢀC(10)
W(2)ꢀC(9)
W(2)ꢀC(26)
PꢀN(1)
2.018(6)
2.019(6)
2.046(7)
2.054(7)
2.061(6)
2.167(5)
1.996(7)
2.030(7)
2.032(7)
2.047(7)
2.068(7)
2.185(5)
1.756(5)
1.781(5)
1.827(5)
1.858(6)
1.859(6)
1.877(7)
1.895(6)
1.850(7)
1.852(7)
1.858(7)
1.917(5)
1.155(7)
1.131(6)
1.142(7)
1.141(7)
1.128(7)
1.153(7)
1.139(7)
1.144(7)
1.131(7)
1.145(7)
1.363(9)
1.412(8)
1.400(7)
1.411(7)
1.363(7)
1.436(7)
1.395(9)
1.407(8)
1.375(9)
1.350(13)
1.396(13)
1.402(10)
1.314(7)
1.514(7)
1.370(7)
1.376(8)
1.380(8)
1.380(9)
1.382(8)
1.374(7)
PꢀN(2)
PꢀC(11)
Si(1)ꢀC(14)
Si(1)ꢀC(12)
Si(1)ꢀC(13)
Si(1)ꢀC(11)
Si(2)ꢀC(15)
Si(2)ꢀC(17)
Si(2)ꢀC(16)
Si(2)ꢀC(11)
O(1)ꢀC(1)
O(2)ꢀC(2)
O(3)ꢀC(3)
O(4)ꢀC(4)
O(5)ꢀC(5)
89.6(2)
97.8(2)
N(1)ꢀPꢀC(11)
N(2)ꢀPꢀC(11)
100.7(2)
105.3(2)
107.8(3)
107.8(3)
108.8(3)
112.0(3)
108.9(3)
111.4(3)
110.2(4)
108.6(4)
108.6(4)
110.6(3)
110.7(3)
108.1(3)
117.9(7)
115.6(5)
178.2(5)
178.0(5)
179.5(6)
174.9(6)
178.5(6)
178.1(7)
174.0(6)
177.6(6)
172.4(6)
178.2(7)
123.0(3)
105.3(3)
118.7(3)
112.0(5)
124.2(4)
123.7(4)
118.1(6)
120.9(6)
120.9(6)
120.5(8)
121.9(9)
119.3(8)
120.3(9)
114.2(6)
125.8(8)
120.0(8)
C(14)ꢀSi(1)ꢀC(12)
C(14)ꢀSi(1)ꢀC(13)
C(12)ꢀSi(1)ꢀC(13)
C(14)ꢀSi(1)ꢀC(11)
C(12)ꢀSi(1)ꢀC(11)
C(13)ꢀSi(1)ꢀC(11)
C(15)ꢀSi(2)ꢀC(17)
C(15)ꢀSi(2)ꢀC(16)
C(17)ꢀSi(2)ꢀC(16)
C(15)ꢀSi(2)ꢀC(11)
C(17)ꢀSi(2)ꢀC(11)
C(16)ꢀSi(2)ꢀC(11)
C(24)ꢀO(11)ꢀC(25)
C(32)ꢀO(12)ꢀC(33)
O(1)ꢀC(1)ꢀW(1)
O(2)ꢀC(2)ꢀW(1)
O(3)ꢀC(3)ꢀW(1)
O(4)ꢀC(4)ꢀW(1)
O(5)ꢀC(5)ꢀW(1)
O(6)ꢀC(6)ꢀW(2)
O(7)ꢀC(7)ꢀW(2)
O(8)ꢀC(8)ꢀW(2)
O(9)ꢀC(9)ꢀW(2)
O(10)ꢀC(10)ꢀW(2)
PꢀC(11)ꢀSi(1)
O(6)ꢀC(6)
O(7)ꢀC(7)
O(8)ꢀC(8)
O(9)ꢀC(9)
O(10)ꢀC(10)
O(11)ꢀC(24)
O(11)ꢀC(25)
O(12)ꢀC(32)
O(12)ꢀC(33)
C(18)ꢀN(1)
C(18)ꢀC(19)
C(19)ꢀC(24)
C(19)ꢀC(20)
C(20)ꢀC(21)
C(21)ꢀC(22)
C(22)ꢀC(23)
C(23)ꢀC(24)
C(26)ꢀN(2)
C(26)ꢀC(27)
C(27)ꢀC(28)
C(27)ꢀC(32)
C(28)ꢀC(29)
C(29)ꢀC(30)
C(30)ꢀC(31)
C(31)ꢀC(32)
PꢀC(11)ꢀSi(2)
Si(1)ꢀC(11)ꢀSi(2)
N(1)ꢀC(18)ꢀC(19)
N(1)ꢀC(18)ꢀW(1)
C(19)ꢀC(18)ꢀW(1)
C(24)ꢀC(19)ꢀC(20)
C(24)ꢀC(19)ꢀC(18)
C(20)ꢀC(19)ꢀC(18)
C(21)ꢀC(20)ꢀC(19)
C(22)ꢀC(21)ꢀC(20)
C(21)ꢀC(22)ꢀC(23)
C(22)ꢀC(23)ꢀC(24)
O(11)ꢀC(24)ꢀC(19)
O(11)ꢀC(24)ꢀC(23)
C(19)ꢀC(24)ꢀC(23)
Bond angles
C(4)ꢀW(1)ꢀC(1)
C(4)ꢀW(1)ꢀC(3)
C(1)ꢀW(1)ꢀC(3)
C(4)ꢀW(1)ꢀC(5)
C(1)ꢀW(1)ꢀC(5)
C(3)ꢀW(1)ꢀC(5)
C(4)ꢀW(1)ꢀC(2)
C(1)ꢀW(1)ꢀC(2)
86.1(2)
90.8(3)
90.1(2)
86.4(3)
91.1(2)
176.8(2)
175.0(3)
90.3(2)

C. Neumann et al. / Journal of Organometallic Chemistry 643–644 (2002) 253–264
259
Table 6 (Continued)
N(2)ꢀC(26)ꢀC(27)
N(2)ꢀC(26)ꢀW(2)
C(27)ꢀC(26)ꢀW(2)
C(28)ꢀC(27)ꢀC(32)
C(28)ꢀC(27)ꢀC(26)
C(32)ꢀC(27)ꢀC(26)
C(27)ꢀC(28)ꢀC(29)
C(30)ꢀC(29)ꢀC(28)
C(29)ꢀC(30)ꢀC(31)
C(32)ꢀC(31)ꢀC(30)
C(31)ꢀC(32)ꢀC(27)
C(31)ꢀC(32)ꢀO(12)
C(27)ꢀC(32)ꢀO(12)
C(18)ꢀN(1)ꢀP
110.3(5)
129.7(4)
119.8(4)
117.9(5)
121.0(5)
121.1(5)
123.0(6)
116.7(6)
122.5(6)
117.9(6)
122.0(6)
122.6(5)
115.4(5)
123.8(4)
124.8(4)
C(26)ꢀN(2)ꢀP
Fig. 4. Molecular structure of 5 in the crystal (ellipsoids represent
30% probability levels; hydrogen atoms are omitted for clarity).
,
Selected bond lengths (A) and angles (°): W1ꢀC1, 2.019(6); W1ꢀC18,
2.167(5); C18ꢀN1, 1.363(7); N1ꢀP, 1.756(5); PꢀC11, 1.827(5); PꢀN2,
1.781(5); N2ꢀC26, 1.314(7); C26ꢀW2, 2.185(5); W2ꢀC6, 1.996(7);
N1ꢀC18ꢀW1, 124.2(4); N1ꢀPꢀN2, 97.8(2); N2ꢀC26ꢀW2, 129.7(4)
(Table 6).
intended to differentiate between P- and N-coordina-
tion of the appropriate heterocycle to the metal.
3.2. General procedure for the synthesis of the o-phenyl-
substituted ethoxycarbene tungsten complexes 2a,c
A mixture of Et2O (40 ml), 15 mmol of o-bromoare-
nes 1a–c and 15 mmol n-BuLi (10 ml of a n-C6H14 1.6
M solution) were added via a dropping funnel to a
suspension of 15 mmol (5.2 g) W(CO)6 in 15 ml Et2O in
a three-necked flask. The resulting solutions were
stirred for 1/2 h and then reduced in vacuo (ca. 0.01
mbar) to dryness, thus obtaining the pentacarbonyl-
Fig. 3. Molecular structure of 2b in the crystal (ellipsoids represent
30% probability levels; hydrogen atoms are omitted for clarity).
,
Selected bond lengths (A) and angles (°): WꢀC1, 2.020(7); WꢀC6,
2.172(7); C6ꢀC7, 1.511(10); O6ꢀC8ꢀC7, 115.0(6); O7ꢀC6ꢀC7, 106.5(6)
(Table 5).
using standard Schlenk techniques with conventional
glassware. Solvents were dried according to standard
procedures. — NMR spectra were recorded on a
1
Bruker AC-200 spectrometer (200 MHz for H; 50.3
MHz for 13C; 81.0 MHz for 31P) using [d]CHCl3 and
[d6]C6H6 as solvent and internal standard; shifts are
given relative to ext. Me4Si (1H, 13C) and 85% H3PO4
(31P). — Mass spectra were recorded on a Finigan
Mat 8430 (70 eV); apart from m/z-values of the
molecule ions, only m/z-values having intensities of
more than 20% are given. — IR spectra were recorded
on a Biorad FT-IR 165 (selected data given). — M.p.
were obtained on a Bu¨chi 535 capillary apparatus. —
Elemental analyses were performed using a Carlo
Erba analytical gas chromatograph. — All products
were separated by column chromatography at low tem-
perature. — The sP-notation in the nomenclature is
Fig. 5. Molecular structure of 6b in the crystal (ellipsoids represent
30% probability levels; hydrogen atoms are omitted for clarity).
,
Selected bond lengths (A) and angles (°): WꢀC1, 2.016(3); WꢀP,
2.4741(7); PꢀC13, 1.763(3); P1ꢀN1, 1.796(2); C13ꢀN1, 1.276(3);
C13ꢀC14, 1.454(3); C13ꢀP1ꢀN1, 42.01(10); C14ꢀC19ꢀO6, 116.0(2);
W1ꢀP1ꢀC6, 122.34(8); N1ꢀP1ꢀC6, 109.12(11); N1ꢀP1ꢀW1, 119.30(8);
W%ꢀC1%, 2.022(3); W%ꢀP%, 2.4785(7); P%ꢀC13%, 1.759(3); P1%ꢀN1%,
1.808(2); C13%ꢀN1%, 1.286(3); C13%ꢀP1%ꢀN1%, 42.22(10); C14%ꢀC19%ꢀO6%,
115.50(2); W1%ꢀP1%ꢀC6%, 121.21(8); N1%ꢀP1%ꢀC6%, 107.37(11);
N1%ꢀP1%ꢀW1%, 122.20(8) (Table 7).

260
C. Neumann et al. / Journal of Organometallic Chemistry 643–644 (2002) 253–264
Table 7 (Continued)
Table 7
,
Bond lengths (A) and angles (°) for complex 6b
C(18%)ꢀC(19%)
1.389(4)
Bond lengths
W(1)ꢀC(1)
W(1)ꢀC(4)
W(1)ꢀC(5)
W(1)ꢀC(3)
W(1)ꢀC(2)
W(1)ꢀP(1)
P(1)ꢀC(13)
P(1)ꢀN(1)
P(1)ꢀC(6)
Si(1)ꢀC(9)
Si(1)ꢀC(8)
Si(1)ꢀC(7)
Si(1)ꢀC(6)
Si(2)ꢀC(11)
Si(2)ꢀC(10)
Si(2)ꢀC(12)
Si(2)ꢀC(6)
N(1)ꢀC(13)
O(1)ꢀC(1)
O(2)ꢀC(2)
O(3)ꢀC(3)
O(4)ꢀC(4)
O(5)ꢀC(5)
O(6)ꢀC(19)
O(6)ꢀC(20)
C(13)ꢀC(14)
C(14)ꢀC(15)
C(14)ꢀC(19)
C(15)ꢀC(16)
C(16)ꢀC(17)
C(17)ꢀC(18)
C(18)ꢀC(19)
W(1%)ꢀC(1%)
W(1%)ꢀC(3%)
W(1%)ꢀC(4%)
W(1%)ꢀC(2%)
W(1%)ꢀC(5%)
W(1%)ꢀP(1%)
P(1%)ꢀC(13%)
P(1%)ꢀN(1%)
P(1%)ꢀC(6%)
Si(1%)ꢀC(7%)
Si(1%)ꢀC(9%)
Si(1%)ꢀC(8%)
Si(1%)ꢀC(6%)
Si(2%)ꢀC(11%)
Si(2%)ꢀC(12%)
Si(2%)ꢀC(10%)
Si(2%)ꢀC(6%)
N(1%)ꢀC(13%)
O(1%)ꢀC(1%)
O(2%)ꢀC(2%)
O(3%)ꢀC(3%)
O(4%)ꢀC(4%)
O(5%)ꢀC(5%)
O(6%)ꢀC(19%)
O(6%)ꢀC(20%)
C(13%)ꢀC(14%)
C(14%)ꢀC(15%)
C(14%)ꢀC(19%)
C(15%)ꢀC(16%)
C(16%)ꢀC(17%)
C(17%)ꢀC(18%)
Bond angles
2.016(3)
2.029(3)
2.039(3)
2.056(3)
2.061(3)
2.4741(7)
1.763(3)
1.796(2)
1.813(3)
1.860(3)
1.867(3)
1.870(3)
1.908(2)
1.863(3)
1.870(3)
1.871(3)
1.911(2)
1.276(3)
1.141(3)
1.138(4)
1.136(4)
1.139(3)
1.145(3)
1.356(3)
1.439(3)
1.454(3)
1.392(3)
1.411(4)
1.371(4)
1.386(4)
1.385(4)
1.385(3)
2.022(3)
2.026(3)
2.037(3)
2.046(3)
2.049(3)
2.4785(7)
1.759(3)
1.808(2)
1.814(3)
1.854(3)
1.865(3)
1.868(3)
1.902(2)
1.858(3)
1.864(3)
1.864(3)
1.909(2)
1.286(3)
1.133(3)
1.138(3)
1.148(3)
1.138(3)
1.148(4)
1.359(3)
1.431(3)
1.460(3)
1.395(3)
1.406(4)
1.376(4)
1.383(4)
1.374(4)
C(1)ꢀW(1)ꢀC(4)
C(1)ꢀW(1)ꢀC(5)
C(4)ꢀW(1)ꢀC(5)
C(1)ꢀW(1)ꢀC(3)
C(4)ꢀW(1)ꢀC(3)
C(5)ꢀW(1)ꢀC(3)
C(1)ꢀW(1)ꢀC(2)
C(4)ꢀW(1)ꢀC(2)
C(5)ꢀW(1)ꢀC(2)
C(3)ꢀW(1)ꢀC(2)
C(1)ꢀW(1)ꢀP(1)
C(4)ꢀW(1)ꢀP(1)
C(5)ꢀW(1)ꢀP(1)
C(3)ꢀW(1)ꢀP(1)
C(2)ꢀW(1)ꢀP(1)
C(13)ꢀP(1)ꢀN(1)
C(13)ꢀP(1)ꢀC(6)
N(1)ꢀP(1)ꢀC(6)
C(13)ꢀP(1)ꢀW(1)
N(1)ꢀP(1)ꢀW(1)
C(6)ꢀP(1)ꢀW(1)
C(9)ꢀSi(1)ꢀC(8)
C(9)ꢀSi(1)ꢀC(7)
C(8)ꢀSi(1)ꢀC(7)
C(9)ꢀSi(1)ꢀC(6)
C(8)ꢀSi(1)ꢀC(6)
C(7)ꢀSi(1)ꢀC(6)
C(11)ꢀSi(2)ꢀC(10)
C(11)ꢀSi(2)ꢀC(12)
C(10)ꢀSi(2)ꢀC(12)
C(11)ꢀSi(2)ꢀC(6)
C(10)ꢀSi(2)ꢀC(6)
C(12)ꢀSi(2)ꢀC(6)
C(13)ꢀN(1)ꢀP(1)
C(19)ꢀO(6)ꢀC(20)
O(1)ꢀC(1)ꢀW(1)
O(2)ꢀC(2)ꢀW(1)
O(3)ꢀC(3)ꢀW(1)
O(4)ꢀC(4)ꢀW(1)
O(5)ꢀC(5)ꢀW(1)
P(1)ꢀC(6)ꢀSi(1)
P(1)ꢀC(6)ꢀSi(2)
Si(1)ꢀC(6)ꢀSi(2)
N(1)ꢀC(13)ꢀC(14)
N(1)ꢀC(13)ꢀP(1)
C(14)ꢀC(13)ꢀP(1)
C(15)ꢀC(14)ꢀC(19)
C(15)ꢀC(14)ꢀC(13)
C(19)ꢀC(14)ꢀC(13)
C(16)ꢀC(15)ꢀC(14)
C(15)ꢀC(16)ꢀC(17)
C(18)ꢀC(17)ꢀC(16)
C(17)ꢀC(18)ꢀC(19)
O(6)ꢀC(19)ꢀC(18)
O(6)ꢀC(19)ꢀC(14)
C(18)ꢀC(19)ꢀC(14)
C(1%)ꢀW(1%)ꢀC(3%)
C(1%)ꢀW(1%)ꢀC(4%)
C(3%)ꢀW(1%)ꢀC(4%)
C(1%)ꢀW(1%)ꢀC(2%)
C(3%)ꢀW(1%)ꢀC(2%)
C(4%)ꢀW(1%)ꢀC(2%)
89.98(11)
89.85(12)
87.09(11)
89.73(12)
90.99(12)
178.03(12)
93.49(12)
175.93(11)
90.81(13)
91.13(14)
178.95(9)
90.94(7)
90.69(8)
89.76(8)
85.60(8)
42.01(10)
111.31(12)
109.12(11)
125.29(9)
119.30(8)
122.34(8)
109.65(15)
108.40(15)
108.60(15)
108.88(12)
112.61(12)
108.61(13)
107.23(13)
109.95(13)
109.49(13)
109.82(12)
108.85(11)
111.40(12)
67.60(15)
116.8(2)
178.4(3)
176.9(3)
178.4(3)
178.2(2)
177.5(3)
113.57(13)
112.36(12)
118.59(12)
132.8(2)
70.39(15)
156.8(2)
119.1(2)
117.7(2)
123.2(2)
121.4(3)
118.9(3)
121.3(3)
119.9(3)
124.6(2)
116.0(2)
119.4(2)
87.42(13)
90.42(12)
88.68(12)
92.88(12)
90.59(12)
176.58(11)

C. Neumann et al. / Journal of Organometallic Chemistry 643–644 (2002) 253–264
261
Table 7 (Continued)
3.2.1. {[Ethoxy-(2-methylphenyl)carbene]penta-
carbonyltungsten(0)} (2a)
C(1%)ꢀW(1%)ꢀC(5%)
C(3%)ꢀW(1%)ꢀC(5%)
C(4%)ꢀW(1%)ꢀC(5%)
C(2%)ꢀW(1%)ꢀC(5%)
C(1%)ꢀW(1%)ꢀP(1%)
C(3%)ꢀW(1%)ꢀP(1%)
C(4%)ꢀW(1%)ꢀP(1%)
C(2%)ꢀW(1%)ꢀP(1%)
C(5%)ꢀW(1%)ꢀP(1%)
C(13%)ꢀP(1%)ꢀN(1%)
C(13%)ꢀP(1%)ꢀC(6%)
N(1%)ꢀP(1%)ꢀC(6%)
C(13%)ꢀP(1%)ꢀW(1%)
N(1%)ꢀP(1%)ꢀW(1%)
C(6%)ꢀP(1%)ꢀW(1%)
C(7%)ꢀSi(1%)ꢀC(9%)
C(7%)ꢀSi(1%)ꢀC(8%)
C(9%)ꢀSi(1%)ꢀC(8%)
C(7%)ꢀSi(1%)ꢀC(6%)
C(9%)ꢀSi(1%)ꢀC(6%)
C(8%)ꢀSi(1%)ꢀC(6%)
C(11%)ꢀSi(2%)ꢀC(12%)
C(11%)ꢀSi(2%)ꢀC(10%)
C(12%)ꢀSi(2%)ꢀC(10%)
C(11%)ꢀSi(2%)ꢀC(6%)
C(12%)ꢀSi(2%)ꢀC(6%)
C(10%)ꢀSi(2%)ꢀC(6%)
C(13%)ꢀN(1%)ꢀP(1%)
C(19%)ꢀO(6%)ꢀC(20%)
O(1%)ꢀC(1%)ꢀW(1%)
O(2%)ꢀC(2%)ꢀW(1%)
O(3%)ꢀC(3%)ꢀW(1%)
O(4%)ꢀC(4%)ꢀW(1%)
O(5%)ꢀC(5%)ꢀW(1%)
P(1%)ꢀC(6%)ꢀSi(1%)
P(1%)ꢀC(6%)ꢀSi(2%)
Si(1%)ꢀC(6%)ꢀSi(2%)
N(1%)ꢀC(13%)ꢀC(14%)
N(1%)ꢀC(13%)ꢀP(1%)
C(14%)ꢀC(13%)ꢀP(1%)
C(15%)ꢀC(14%)ꢀC(19%)
C(15%)ꢀC(14%)ꢀC(13%)
C(19%)ꢀC(14%)ꢀC(13%)
C(16%)ꢀC(15%)ꢀC(14%)
C(15%)ꢀC(16%)ꢀC(17%)
C(18%)ꢀC(17%)ꢀC(16%)
C(17%)ꢀC(18%)ꢀC(19%)
O(6%)ꢀC(19%)ꢀC(18%)
O(6%)ꢀC(19%)ꢀC(14%)
C(18%)ꢀC(19%)ꢀC(14%)
91.01(13)
178.27(11)
90.62(13)
90.20(13)
179.51(11)
92.10(8)
89.60(8)
87.09(8)
89.47(9)
42.22(10)
112.65(12)
107.37(11)
124.85(9)
122.20(8)
121.24(8)
109.36(15)
108.86(14)
107.92(14)
107.71(12)
109.27(13)
113.66(12)
112.22(15)
106.86(13)
108.91(15)
107.96(12)
110.45(12)
110.37(12)
66.83(14)
118.0(2)
1
Yield: 5.23 g (74%), m.p. 48 °C; H-NMR (CDCl3):
3
1.56 (t, JH,H=7.1 Hz, 3H, OꢀCH2CH3), 2.09 (s, 3H,
3
CH3), 4.91 (q, JH,H=7.1 Hz, 2H, OꢀCH2CH3), 7.10
(mc, 4H, Ar); 13C{1H}-NMR (CDCl3): 14.4 (s,
OꢀCH2CH3), 18.6 (s, CH3), 95.1 (s, OꢀCH2CH3), 124.8
(s, Ar), 127.9 (s, Ar), 130.2 (s, Ar), 196.6 (s, cis-CO),
203.0 (s, trans-CO); MS (70 eV, EI) (184W): m/z (%)=
472 (40) [M+], 444 (60) [M+−CO], 359 (65) [M+−
4CO], 330 (100) [M+−5CO]; Anal. Calc. for
C15H12O6W (472.0): C, 38.16; H, 2.56. Found: C, 38.39;
H, 2.58%.
3.2.2. {[Ethoxy-(2-N,N-dimethylaminophenyl)carbene]-
pentacarbonyltungsten(0)} (2c)
Yield: 5.2 g (71%); 1H-NMR (CDCl3): 0.81 (t,
3JH,H=7.1 Hz, 3H, OꢀCH2CH3), 2.13 (s, 6H, NCH3),
3
4.14 (q, JH,H=7.1 Hz, 2H, OꢀCH2CH3), 7.10 (mc, 4H,
Ar); 13C{1H}-NMR (CDCl3): 13.1 (s, OꢀCH2CH3),
43.2 (s, NCH3), 78.1 (s, OꢀCH2CH3), 117.2 (s, Ar),
128.6 (s, Ar), 145.7 (s, Ar), 196.6 (s, cis-CO), 203.0 (s,
trans-CO); 330.5 (WꢁC).
3.3. General procedure for the synthesis of the o-phenyl-
substituted aminocarbene tungsten complexes 3a–c
178.5(3)
177.6(3)
177.9(3)
178.6(3)
The ethoxycarbene complexes 2a–c were dissolved in
Et2O and NH3 and was bubbled for 1/2 h through the
solution until the color turned from red to orange.
After removing the solvent in vacuo (ca. 0.01 mbar)
and washing the residues with n-C5H12, the aminocar-
bene tungsten complexes 3a–c were obtained as yellow
crystals.
178.9(3)
115.14(13)
111.89(12)
118.29(13)
133.4(2)
70.95(16)
155.7(2)
119.6(2)
119.0(2)
121.4(2)
120.7(3)
118.8(3)
122.0(3)
119.6(3)
125.2(2)
115.5(2)
119.3(2)
3.3.1. {[Amino(2-methylphenyl)carbene]penta-
carbonyltungsten(0)} (3a)
1
Yield: 4.8 g (72%), m.p. 108 °C; H-NMR (CDCl3):
2.26 (s, 3H, ArꢀCH3), 6.90 (mc, 1H, o-Ar), 7.18 (mc,
3H, m,p-Ar), 8.53 (s, 1H, NH), 8.82 (s, 1H, NH);
13C{1H}-NMR (CDCl3): 19.2 (s, ArꢀCH3), 121.3 (s,
Ar), 126.8 (s, o-Ar), 127.9 (s, Ar), 130.8 (s, Ar), 153.1
1
(s, i-Ar), 197.9 (s, JC,W=128.4 Hz, cis-CO), 203.7 (s,
1
1JC,W=125.4 Hz, trans-CO), 272.3 (s, JC,W=88.5 Hz,
WꢁC); MS (70 eV, EI) (184W): m/z (%)=443 (55)
[M+], 331 (100) [M+−4CO], 303 (90) [M+−5CO]; IR
(KBr, w(CO)) w˜ =2066 (m), 1943 (s), 1895 (s), 1870
(s) cm−1; Anal. Calc. for C13H9NO5W (443.1): C,
35.24; H, 2.15; N, 3.16. Found: C, 34.48; H, 2.03; N,
3.05%.
(acyl)tungstates. The residues were then resolved in a
two-phase system of water (50 ml) and n-C5H12 (100
ml) and 16.5 mmol (3.13 g) Meerwein salt was then
added in small portions. The thus resulting ethoxycar-
bene complexes were filtered using a short column
containing SiO2 and a layer of MgSO4 on top (4:1
ratio). Evaporating of all volatile compounds in vacuo
(ca. 0.01 mbar) and recrystallization from n-C5H12
yielded the ethoxycarbene complexes as red solids.
3.3.2. {[Amino(2-methoxyphenyl)carbene]penta-
carbonyltungsten(0)} (3b)
1
Yield: 5.27 g (77%), m.p. 104 °C; H-NMR (CDCl3):
3.85 (s, 3H, OCH3), 7.09 (mc, 3H, Ar), 7.31 (mc, 1H,
Ar), 8.54 (s, 1H, NH), 8.96 (s, 1H, NH); 13C-NMR

262
C. Neumann et al. / Journal of Organometallic Chemistry 643–644 (2002) 253–264
(CDCl3): 55.4 (s, OCH3), 111.3 (s, Ar), 120.7 (s, Ar),
126.1 (s, Ar), 130.5 (s, Ar), 140.5 (s, Ar), 151.7 (s, Ar),
198.4 (s, cis-CO), 203.9 (s, trans-CO), 264.5 (s, WꢁC);
MS (70 eV, EI) (184W): m/z (%)=459 (10) [M+], 347
(80) [M+−4CO], 317 (100) [M+−5CO]; IR (KBr,
(50) [M+−1CO], 416 (40) [M+−2CO], 388 (35)
[M+−3CO], 386 (33) [M+−2CO−2CH3], 360 (40)
[M+−4CO], 358 (40) [M+−3CO−2CH3], 332 (80)
[M+−5CO], 330 (100) [M+−4CO−2CH3]; IR (KBr,
w(CO)) w˜ =2058 (w), 1917 (s), 1894 (s) cm−1; Anal.
Calc. for C14H12N2O5W (471.5): C, 35.62; H, 2.56; N,
5.93. Found: C, 34.39; H, 2.57; N, 5.21%.
w(CO))
w˜ =2064 (m), 1980 (s), 1937 (s), 1890 (vs)
cm−1
.
3.3.3. {[Amino(2-N,N-dimethylaminophenyl)carbene]-
pentacarbonyltungsten(0)} (3c)
Yield: 4.82 g (68%), m.p. 103 °C; H-NMR (CDCl3):
3.4. General procedure for the synthesis of
o-phenyl-substituted 2H-azaphosphirene tungsten
complexes 6a–c
1
2.72 (s, 6H, NCH3), 7.06 (mc, 2H, Ar), 7.29 (mc, 2H,
Ar), 8,74 (s, 1H, NH), 9.87 (s, 1H, NH); 13C-NMR
(CDCl3): 44,7 (s, NCH3), 119.3 (s, Ar), 124.8 (s, Ar),
130.2 (s, Ar), 132.4 (s, Ar), 142.4 (s, Ar), 148,3 (s, i-Ar),
199.9 (s, cis-CO), 207.2 (s, trans-CO), 268.8 (s, WꢁC);
MS (70 eV, EI) (184W): m/z (%)=472 (5) [M+], 444
Appropriate carbene complexes 3a–c (1 mmol) and
[bis(trimethyl-silyl)methylene]chlorophosphane (4) (1
mmol) were dissolved in MeCN (10 ml) and 4 ml Et3N
was added. The solution was stirred for 3 h at ambient
temperature, whereby the reactions were controlled by
31P-NMR spectroscopy. At the end of the reaction the
solvent was evaporated in vacuo (ca. 0.01 mbar). The
residues were dissolved in ether, the precipitated
Et3NHCl filtered off and the filtrates were reduced in
vacuo (ca. 0.01 mbar) to dryness. The residue was
purified by low temperature column chromatography
(neutral SiO2, 8×2 cm, −10 °C, petrol ether (50/70)–
Et2O 95/5).
3.4.1. {[2-Bis(trimethylsilyl)methyl-3-(2-methylphenyl)-
2H-azaphosphirene-sP]pentacarbonyl tungsten(0)} (6a)
Yield: 630 mg (92%), m.p. 107 °C (dec.); 13C-NMR
3
3
(CDCl3): 1.2 (d, JP,C=3.1 Hz, SiCH3), 2.1 (d, JP,C
=
1
3.1 Hz, SiCH3), 20.7 (s, ArꢀCH3), 26.8 (d, JP,C=23.8
Hz, CH), 125.0 (d, JP,C=14.1 Hz, Ar), 126.6 (s, Ar),
128.5 (s, Ar), 131.8 (s, Ar), 133.4 (d, JP,C=9.5 Hz, Ar),
140.8 (d, JP,C=2.7 Hz, Ar), 191.9 (s, PCN), 196.4 (d,
2JP,C=9.0 Hz, cis-CO), 197.7 (s, JP,C=35.8 Hz, trans-
2
CO); 31P{1H}-NMR (CDCl3): −128.3 (s, JW,P=292.8
1
Hz); MS (70 eV, EI) (184W): m/z (%)=631 (5) [M+], 73
(100) [Si(CH3)+3 ]; IR (KBr, w(CO)) w˜ =2072
(m), 1987 (w), 1963 (s), 1943 (s), 1923 (vs)
cm−1
;
Anal. Calc. for C20H26NO5PSi2W (631.02): C, 38.04; H,
4.15; N, 2.22. Found: C, 37.60; H, 4.26; N, 2.21%.
Scheme 5. Catalytic ring expansion reactions of 2H-azaphosphirene
complexes 6a–c and 7d using ferrocenium hexafluorophosphate and
benzonitrile.
3.4.2. {[2-Bis(trimethylsilyl)methyl-3-(2-methoxy-
phenyl)-2H-azaphosphirene-sP]pentacarbonyl
tungsten(0)} (6b)
1
Yield: 616 mg (76%), m.p. 92 °C; H-NMR (CDCl3):
0.05 (s, 9H, SiCH3), 0.31 (s, 9H, SiCH3), 0.64 (d,
2JH,H=2.9 Hz, 1H, CH), 3.99 (s, 3H, OCH3), 6.85 (mc,
1H, Ar), 7.10 (mc, 1H, Ar) 7.60 (mc, 1H, Ar), 7.95 (mc,
1H, Ar); 13C-NMR (CDCl3): 1.2 (d, 3JP,C=3.1 Hz,
3
1
SiCH3), 2.1 (d, JP,C=3.1 Hz, SiCH3), 27.3 (d, JP,C
13.1 Hz, CH), 55.8 (s, OCH3), 111.9 (s, Ar), 115.5 (d,
P,C=13.1 Hz, Ar), 121.7 (s, Ar), 130.0 (s, Ar), 135.8 (s,
=
J
2
Ar), 158.9 (s, Ar), 189.6 (s, PCN), 196.1 (d, JP,C=8.7
Hz, cis-CO), 198.5 (d, 2JP,C=35.9 Hz, trans-CO);
Fig. 6. Possible reactive intermediates of the reactions of complexes
6b,c with benzonitrile.
31P{1H}-NMR (CDCl3): −110.2 (s, JW,P=294.6 Hz);
1

C. Neumann et al. / Journal of Organometallic Chemistry 643–644 (2002) 253–264
263
MS (70 eV, EI) (184W): m/z (%)=647 (5) [M+], 574
(10) [M−SiMe+3 ], 486 (80) [(OC)4WPCNCH(SiMe3)+2 ],
430 (100) [(OC)2WPCNCH(SiMe3)+2 ], 133 (25)
[C4H4(OMe)CN+], 73 (100) [Si(CH3)+3 ].
(s, Ar), 130.8 (s, Ar), 130.9 (s, Ar), 131.2 (s, Ar), 132.3
(s, Ar), 132.4 (s, Ar), 136.2 (d, JP,C=3.8 Hz, Ar), 140.8
(d, JP,C=4.4 Hz, Ar), 169.0 (d, 2+3JP,C=4.3 Hz,
PNC), 197.2 (d, 2JP,C=6.1 Hz, cis-CO), 198.3 (d,
1+4JP,C=22.6 Hz, PCN), 203.6 (d, 2JP,C=25.7 Hz,
1
3.4.3. {[2-Bis(trimethylsilyl)methyl-3-(2-N,N-dime-
thylaminophenyl)-2H-azaphosphirene-sP]-penta-
carbonyltungsten(0)} (6c)
trans-CO); 31P{1H}-NMR (CDCl3): 115.8 (s, JW,P
=
229.2 Hz); MS (70 eV, EI) (184W): m/z (%)=734 (10)
[M+], 706 (25) [M+−1CO], 678 (70) [M+−2CO], 547
(15) [M++H+−PhCN−3CO], 293 (20) [M+−
W(CO)5−PhCN−CH3], 73 (100) [SiMe+3 ]; Anal. Calc.
for C27H31N2O5PSi2W (734.2): C, 44.15; H, 4.25; N,
3.81. Found: C, 43.51; H, 4.08; N, 3.42%.
1
Yield: 269 mg (41%), m.p. 92 °C; H-NMR (CDCl3):
0.02 (s, 9H, SiCH3), 0.29 (s, 9H, SiCH3), 0.68 (d,
2JH,H=1.7 Hz, 1H, CH), 2.54 (s, 6H, NCH3), 6.58 (d,
3JHH=8.33 Hz, 1H, Ar), 6.78 (ddd, br, 1H, Ar), 7.04
(ddd,
JHH=8.78, 1.72 Hz, 1H, Ar), 8.09 (dd,
J
HH=7.72, 1.67 Hz, 1H, Ar); 13C-NMR (CDCl3): 1.3
3.5.2. {[2-Bis(trimethylsilyl)methyl-3-(2-methoxy-
phenyl)-5-phenyl-2H-1,4,2-diazaphosphole-sP]-penta-
carbonyltungsten(0)} (8b)
(d, 3JP,C=2.8 Hz, SiCH3), 2.1 (d, 3JP,C=2.9 Hz,
1
SiCH3), 27.3 (d, JP,C=24.3 Hz, CH), 44.3 (s, NCH3),
112.8 (s, Ar), 118.4 (s, Ar), 120.5 (s, Ar), 128.3 (s, Ar),
135.7 (s, Ar), 154.2 (d, JP,C=2.5 Hz, Ar), 187.8 (s,
PCN), 196.6 (d, 2JP,C=8.8 Hz, cis-CO), 198.1 (d,
2JP,C=35.1 Hz, trans-CO); 31P{1H}-NMR (CDCl3):
1
Yield: 247 mg (33%), m.p. 70 °C (dec.); H-NMR
(CDCl3): −0.17 (s, 9H, SiCH3), 0.58 (s, 9H, SiCH3),
2
1.28 (d, JP,H=4.1 Hz, 1H, CH), 4.02 (s, 3H, OCH3),
3
7.02 (d, JH,H=8.32 Hz, 1H, Ar), 7.17 (mc, 1H, Ar),
1
−125.1 (s, JW,P=292.8 Hz); MS (70 eV, EI) (184W):
7.53 (mc, 1H, Ar), 8.56 (mc, 2H, Ar), 8.73 (dd, br,
3JH,H=7.91 Hz, 1H, Ar); 13C{1H}-NMR (CDCl3): 2.7
(d, 3JP,C=1.9 Hz, SiCH3), 3.8 (d, 3JP,C=3.1 Hz,
m/z (%)=660 (5) [M+], 486 (80) [(OC)4WPCNCH-
(SiMe3)+2 ], 458 (25) [(OC)3WPCNCH(SiMe3)+2 ], 430
(45) [(OC)2WPCNCH(SiMe3)+2 ], 146 (25) [C4H4-
(NMe2)CN+], 73 (100) [Si(CH3)+3 ]; IR (KBr, w(CO))
w˜ =1920.5 (vs), 1951.2 (s), 1987 (w), 2071 (m); Anal.
Calc. for C21H29N2O5PSi2W (660.1): C, 38.19; H, 4.43;
N, 4.24. Found: C, 37.51; H, 4.56; N, 3.83%.
1
SiCH3), 13.8 (d, JP,C=3.7 Hz, CH), 54.6 (s, OCH3),
111.3 (s, Ar), 121.7 (s, Ar), 122.4 (s, Ar), 122.9 (s, Ar),
128.6 (s, Ar), 130.4 (s, Ar), 130.5 (d, JP,C=3.6 Hz, Ar),
131.8 (s, Ar), 135.6 (s, Ar), 158.8 (d, JP,C=2.3 Hz, Ar),
1+4
167.9 (d, 2+3JP,C=4.1 Hz, PNC), 196.5 (d,
J
P,C
=
2
24.5 Hz, PCN), 197.8 (d, JP,C=6.8 Hz, cis-CO), 198.2
3.5. General procedure for the synthesis of the
2H-1,4,2-diazaphosphole complexes 8a–d
(d, JP,C=22.3 Hz, trans-CO); 31P{1H}-NMR (CDCl3):
2
111.8 (s, JW,P=222.6 Hz); MS (70 eV, EI) (184W): m/z
1
(%)=750 (10) [M+], 722 (30) [M+−1CO], 694 (50)
[M+−2CO], 666 (25), [M+−3CO], 563 (40) [M++
H+−PhCN−3CO], 507 (20) [M++H+−PhCN−
5CO], 411 (20) [M+−W(CO)5−CH3], 293 (25)
[M+−W(CO)5−PhCN−OCH3] 73 (100) [SiMe+3 ].
To solutions of 1 mmol each of the 2H-azaphos-
phirene complexes 6a–c and 7d [19], dissolved in 4 ml
of CH2Cl2, 0.2 mmol (61 mg) of ferrocenium hex-
afluorophosphate and 2 mmol (0.2 ml) benzonitrile
were added. The reaction mixtures were stirred at ambi-
ent temperature for 3 h (reaction monitoring by 31P-
NMR spectroscopy). Evaporation of the solvent in
vacuo (ca. 0.01 mbar), low temperature column chro-
matography (neutral SiO2, 8×2 cm, −15 °C, petrol
ether (50/70)–Et2O 95/5) and evaporation of the sol-
vent yielded the 2H-1,4,2-diazaphosphole complexes
8a–c and 8d [6] as orange solids.
3.5.3. {[2-Bis(trimethylsilyl)methyl-3-(2-N,N-
dimethylaminophenyl)-5-phenyl-2H-1,4,2-
diazaphosphole-sP]-pentacarbonyltungsten(0)} (8c)
1
Yield: 247 mg (33%), m.p. 73 °C (dec.); H-NMR
(CDCl3): −0.02 (s, 9H, SiCH3), 0.58 (s, 9H, SiCH3),
2
1.28 (d, JP,H=4.1 Hz, 1H, CH), 2.58 (s, 6H, NCH3),
7.21 (mc, 2H, Ar), 7.54 (mc, 5H, Ar), 8.54 (mc, 2H, Ar);
3
3.5.1. {[2-Bis(trimethylsilyl)methyl-3-(2-methylphenyl)-
5-phenyl-2H-1,4,2-diazaphosphole-sP]-pentacarbonyl-
tungsten(0)} (8a)
13C{1H}-NMR (CDCl3): 2.8 (d, JP,C=2.8 Hz, SiCH3),
3
1
3.6 (d, JP,C=3.7 Hz, SiCH3), 22.5 (d, JP,C=14.3 Hz,
CH), 46 (s, NCH3), 124.3 (s, Ar), 128.7 (s, Ar), 130.6
(s, Ar), 130.8 (s, Ar), 130.9 (s, Ar), 132.4 (s, Ar), 132.8
(s, Ar), 132.4 (s, Ar), 134.9 (d, JP,C=1.8 Hz, Ar), 154.3
(s, Ar), 169.0 (d, 2+3JP,C=4.3 Hz, PNC), 197.2 (d,
2JP,C=6.1 Hz, cis-CO), 198.2 (d, 1+4JP,C=22.1 Hz,
1
Yield: 640 mg (86%), m.p. 55 °C (dec.); H-NMR
(CDCl3): 0.01 (s, 9H, SiCH3), 0.61 (s, 9H, SiCH3), 1.31
2
(d, JP,H=5.2 Hz, 1H, CH), 2.99 (s, 3H, CH3), 7.51
3
(mc, 3H, Ar), 7.64 (mc, 3H, Ar), 8.05 (d, JH,H=7.49
2
Hz, 1H, Ar), 8.56 (dd, JH,H=7.23/1.77 Hz, 2H, Ar);
PCN), 199.9 (d, JP,C=20.7 Hz, trans-CO); 31P{1H}-
3
1
13C{1H}-NMR (CDCl3): 2.9 (d, JP,C=1.9 Hz, SiCH3),
NMR (CDCl3): 114.4 (s, JW,P=236.7 Hz); MS (70 eV,
3
1
3.7 (d, JP,C=2.6 Hz, SiCH3), 18.4 (d, JP,C=7.1 Hz,
CH), 24.2 (s, CH3), 125.63 (s, Ar), 128.7 (s, Ar), 130.6
EI) (184W): m/z (%)=766 (10) [M+], 738 (30) [M+−
1CO], 710 (50) [M+−2CO], 73 (100) [SiMe+3 ].

264
C. Neumann et al. / Journal of Organometallic Chemistry 643–644 (2002) 253–264
[13] R. Streubel, C. Neumann, P.G. Jones, J. Chem. Soc. Dalton
4. Supplementary material
Trans. (2000) 2495.
[14] R. Streubel, J. Jeske, P.G. Jones, R. Herbst-Irmer, Angew.
Chem. Int. Ed. Engl. 33 (1994) 80.
[15] E.O. Fischer, H.J. Kollmeier, Chem. Ber. 104 (1971) 1339.
[16] K.H. Do¨tz, H.-G. Erben, W. Staudacher, K. Harms, J.
Organomet. Chem. 155 (1988) 177.
Crystallographic data (excluding structure factors)
for the structures reported in this paper have been
deposited with the Cambridge Crystallographic Data
Centre as supplementary publication no. 174447 (2b),
174448 (5), 174449 (6b), Copies of the data can be
obtained free of charge on application to The Director,
CCDC, 12 Union Road, Cambridge CB2 1EZ, UK
[fax: +44-1223-336033; e-mail: deposit@ccdc.cam.
ac.uk or www: http://www.ccdc.cam.ac.uk].
[17] Solution and refinement of 2b, 5 and 6b: Crystal data for all
structures are presented in Table 3. Structure determination of 2b
(Acorn): A cut orange block was mounted in inert oil and
measured by ꢀ–q-scans using Mo–Ka radiation (graphite
monochromator) on a Stoe STADI-4 diffractometer. After ab-
sorption correction („-scans) all unique data were used for
calculations (program SHELXL-93 [24]). The structure was solved
by direct methods and refined anisotropically by full-matrix
least-squares on F2. All methyl groups were refined as rigid
groups, all other protons with a riding model. Structure determi-
nation of 5 (praktin): A orange tablet was mounted in inert oil
and measured by ꢀ-scans using Mo–Ka radiation (graphite
monochromator) on a Siemens P4 diffractometer. After absorp-
tion correction („-scans) all unique data were used for calcula-
tions (program SHELXL-97 [25]). The structure was solved by the
heavy atom method and refined as above. Hydrogen atoms were
refined with a riding model, except rigid methyl groups and free
refined NH protons. Structure determination of 6b (neander): An
irregular colorless tablet was mounted in inert oil and measured
by ꢀ-scans using Mo–Ka radiation (graphite monochromator)
on a Bruker SMART 1000 CCD diffractometer. After absorp-
tion correction (multiple scans) all unique data were used for
calculations (program SHELXL-97 [25]). The structure was solved
by the heavy atom method and refined as above. All hydrogen
atoms (except rigid methyl groups) were refined with a riding
model.
[18] K.H. Do¨tz, H. Fischer, P. Hofmann, F.R. Kreissl, U. Schubert,
K. Weiss, in: D. Seyferth (Ed.), Transition Metal Carbene Com-
plexes, Verlag Chemie, Weinheim, 1983.
[19] R. Streubel, A. Ostrowski, S. Priemer, U. Rohde, J. Jeske, P.G.
Jones, Eur. J. Inorg. Chem. (1998) 257.
[20] R. Appel, A. Westerhaus, Tetrahedron Lett. 22 (1981) 2159.
[21] R. Streubel, S. Priemer, F. Ruthe, P.G. Jones, D. Gudat, Eur. J.
Inorg. Chem. (1998) 575.
[22] Although the Hammet constants were not determined for the
o-substituents, their values should be very similar to those of the
p-hammett constants: C. Hansch, A. Leo, S.H. Unger, K.H.
Kim, D. Nikaitani, E.J. Lien, J. Med. Chem. 16 (1973) 1207.
[23] F. Mathey, M. Regitz, in: A.R. Katritzky, C.W. Rees, E.F.V.
Scriven (Eds.), Comprehensive Heterocyclic Chemistry II, vol.
1A, Pergamon, Oxford, 1996, p. 277.
Acknowledgements
We are grateful to the Fonds der Chemischen Industrie
and the Deutsche Forschungsgemeinschaft for financial
support.
References
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