Multifunctional 2H-1,2-Azaphosphole Complexes: A Good Starting Point for the Synthesis of Functional 1,2-Azaphospholide Complexes?

Article abstract of DOI:10.1021/om030547x

The thermolysis of P-functionalized 7-phosphanorbornadiene tungsten complexes in o-xylene in the presence of various carbonitriles and dimethyl acetylene dicarboxylate (DMAD) was investigated. The resulting complexes were investigated by elemental analysis, NMR spectroscopy, UV/Vis spectroscopy, IR spectroscopy, mass spectroscopy and X-ray diffraction method. The analytical data obtained confirmed the molecular structures of the compounds, which were separated and purified by column chromatography at low temperature and subsequent crystalliztion. The NMR spectra displayed three resonances for the 2h-1,2-azaphosphole ring with different phosphorus-carbon coupling constant magnitudes.

Full text of DOI:10.1021/om030547x

Organometallics 2003, 22, 5427-5435
5427
Mu ltifu n ction a l 2H-1,2-Aza p h osp h ole Com p lexes: A Good
Sta r tin g P oin t for th e Syn th esis of F u n ction a l
1,2-Aza p h osp h olid e Com p lexes?
Rainer Streubel,*,† Nils Hoffmann,‡ Gerd von Frantzius,† Cathleen Wismach,‡
Peter G. J ones,‡ Hans-Martin Schiebel,§ J o¨rg Grunenberg,§ He´le`ne Vong,
Pauline Chaigne, Carine Compain, Ngoc Hoa Tran Huy,*, and
Francois Mathey*,
Institut fu¨r Anorganische Chemie, Gerhard-Domagk-Strasse 1, D-53121 Bonn, Germany,
Institut fu¨r Anorganische und Analytische Chemie der Technischen Universita¨t Braunschweig,
P.O. Box 3329, 38023 Braunschweig, Germany, Institut fu¨r Organische Chemie der
Technischen Universita¨t Braunschweig, P.O. Box 3329, 38023 Braunschweig, Germany, and
Laboratoire He´te´roe´le´ments et Coordination, UMR CNRS 7653, DCPH, Ecole Polytechnique,
91128 Palaiseau Cedex, France
Received J uly 22, 2003
The thermolysis of P-functionalized 7-phosphanorbornadiene tungsten complexes 3a -d
in o-xylene at 120 °C in the presence of various carbonitriles and dimethyl acetylenedi-
carboxylate (DMAD) has been investigated. The reaction of complex 3a , 1-piperidino
carbonitrile, and DMAD yielded a product mixture, whereby 2H-1,2-azaphosphole complex
6 was formed in ca. 40-45% yield together with diazaphosphole complexes 7 (ca. 10-15%)
and 8 (ca. 10-15%) and other nonidentified products (ca. 30%). Unfortunately, none of these
products could be separated by column chromatography. In marked contrast, reactions of
7-phosphanorbornadiene tungsten complexes 3a -d with triphenylphosphane-imino carbo-
nitrile and DMAD led to P-functionalized 2H-1,2-azaphosphole complexes 11a -d in good to
excellent yields. Preliminary investigations of decomplexation reactions revealed a remark-
able thermal stability of 11a -d : no reaction occurred with bis(diphenylphosphino)ethane
(DPPE) at 140 °C. Preliminary studies of exocyclic P-C bond cleavage reactions of 2H-1,2-
azaphosphole complexes 11a ,b using potassium tert-butanolate (KOtBu) showed instanta-
neous reactions and color change from yellow to dark red; an intermediate was detected by
31P NMR spectroscopy. Treatment with an excess of methyl iodide led to one major product,
which, most probably, is the N-methyl-substituted 1H-1,2-azaphosphole complex 13;
unfortunately, chromatography failed and it could only be observed by 31P NMR spectroscopy.
A comparative study on P-C bond cleavage/methylation reactions using monofunctional
2H-1,3,2-diazaphosphole complex 14 and the system KOtBu/methyl iodide showed the
selective formation of the P-methyl-substituted 2H-1,3,2-diazaphosphole complex 16;
complexes 14 and 16 were prepared using the Cu(I)Cl route. Complexes 11a -d , 14, and 16
were characterized by elemental analyses, NMR, UV/vis, IR, and mass spectroscopy and, in
addition, by single-crystal X-ray diffraction in the case of 11a -d . Additionally, we
investigated selected isomers of lithium and potassium 1,2-azaphospholides by ab initio
calculations using HF and MP2/6-311++G(2d,p) level of theory; stability, structure, and
aromaticity aspects are discussed.
In tr od u ction
phane-ylide complexes III via 1,1-addition of nitriles
and electrophilic terminal phosphanediyl complexes4 II
(Scheme 1). The synthetic utility of transient nitrilium
phosphane-ylide complexes in organophosphorus chem-
istry5 motivated us to extend their chemistry by using
In recent years, we have studied the synthesis of 2H-
1,2-azaphosphole complexes IV using three-component
reactions of 2H-azaphosphirene complexes I,1 nitriles,
and alkynes,2,3 thus forming transient nitrilium phos-
(2) Wilkens, H.; Ruthe, F.; J ones, P. G.; Streubel, R. J . Chem. Soc.,
Chem. Commun. 1998, 1529.
(3) Wilkens, H.; Ostrowski, A.; J eske, J .; Ruthe, F.; J ones, P. G.;
Streubel, R. Organometallics 1999, 18, 5627.
(4) Reviews of electrophilic terminal phosphinidene (phosphanediyl)
complexes: (a) Mathey, F. Angew. Chem. 1987, 99, 285; Angew. Chem.,
Int. Ed. Engl. 1987, 26, 275. (b) Dillon, K. B. Mathey, F.; Nixon, J . F.
In Phosphorus: The Carbon Copy, Wiley: Chichester, 1998; p 19. (c)
Mathey, F.; Tran Huy, N. H.; Marinetti, A. Helv. Chim. Acta 2001,
84, 2938. (d) Lammertsma, K.; Vlaar, M. J . M. Eur. J . Org. Chem.
2002, 1127. (e) Lammertsma, K. Top. Cur. Chem. 2003, 229, 95.
* Corresponding authors. (R.S.) Telefax: Int. + 228/73-9616. E-
mail: r.streubel@uni-bonn.de. (F.M.) E-mail: francois-mathey@
polytechnique.fr.
† Institut fu¨r Anorganische Chemie.
‡ Institut fu¨r Anorganische und Analytische Chemie der Technis-
chen Universita¨t Braunschweig.
§ Institut fu¨r Organische Chemie der Technischen Universita¨t
Braunschweig.
Laboratoire He´te´roe´le´ments et Coordination.
(1) Streubel, R. Coord. Chem. Rev. 2002, 227, 172.
10.1021/om030547x CCC: $25.00 © 2003 American Chemical Society
Publication on Web 11/27/2003

5428 Organometallics, Vol. 22, No. 26, 2003
Streubel et al.
Sch em e 1. Syn th esis of 2H-1,2-Aza p h osp h ole
Sch em e 2. Esta blish ed Ap p r oa ch to F u n ction a l
P h osp h olid es
Com p lexes
Here, we report the synthesis and structures of
multifunctional 2H-1,2-azaphosphole complexes and
reactions thereof, which provide evidence by phosphorus
NMR for the intermediate generation of 1,2-azaphos-
pholide complexes. Furthermore, comparative reactions
of a monofunctional 2H-1,3,2-diazaphosphole complex
provide strong evidence for the formation of a 1,3,2-
diazaphospholide derivative and thus further indirect
support for our assumption of the 1,2-azaphospholide
formation. We also report ab initio calculations of
stability, structure, and aromaticity of selected isomers
of lithium and potassium 1,2-azaphospholides at the HF
and rMP2(fc)/6-311++G(2d,p) level of theory.
7-phosphanorbornadiene complexes and 1-piperidino
carbonitrile in the presence6 or absence7 of dimethyl
acetylenedicarboxylate (DMAD). In these cases, we
observed similar reactivity of the nitrilium phosphane-
ylide complexes thus generated. Nevertheless, there
were two remarkable differences, namely, different
π-bond selectivity and regioselectivity: both were ex-
plained by assuming less sterically crowded transition
states of the [3+2] cycloaddition reactions.6,7
Although we were now able to synthesize a variety
of 2H-1,2-azaphosphole complexes, two main targets in
this area still remained: The synthesis of noncoordi-
nated 2H-1,2-azaphospholes8 and 1,2-azaphospholides,9
the latter in a main group- or transition metal-
coordinated fashion. In view of the central importance
of anionic 6π-aromatic ligand systems such as cyclo-
pentadienides10 and phospholides11,12 in coordination
and organometallic chemistry, 1,2-azaphospholides could
be envisaged as promising novel 6π-aromatic ligands.
Therefore, we felt encouraged to use P-functional 7-phos-
phanorbornadiene complexes, which could give rise to
1,2-azaphospholide complexes using mild procedures
that were originally developed to access functional
phospholides; for example, cleavage of the exocyclic P-C
bond of â-ethyl-functionalized phosphole complexes 1a ,b
was achieved with potassium tert-butanolate to furnish
phospholide 2 (Scheme 2).13 This methodology was also
successful if the phosphorus is coordinated to a transi-
tion metal, e.g., in 1,2-dihydro-1,2-diphosphinine com-
plexes.14
Resu lts
We initially focused our attention on the transient
generation of nitrilium phosphane-ylide complexes with
P-functional substituents and their [3+2] trapping with
DMAD. Because of our previous success in employing
1-piperidino carbonitrile as carbonitrile component, we
first studied the thermal decomposition of 7-phospha-
norbornadiene complex 3a 15 in o-xylene at 120 °C in the
presence of 2 equiv of carbonitrile 4a and DMAD (5).
Although the targeted 2H-1,2-azaphosphole complex 6
was probably formed (δ 31P ) 79.6, 1J (W,P) ) 253.6 Hz)
(ca. 40-45%), the outcome was disappointing because
of the formation of a complicated product mixture
(Scheme 3). Other products such as the regioisomeric
diazaphosphole complexes 77 (ca. 10-15%) and 87 (ca.
10-15%) were identified using authentic samples. Other
byproducts were formed in small amounts (altogether
ca. 30%; δ 31P ) 214.4, 205.6, 123.3, 76.4, and 71.2) but
could not be identified. Probably, these products stem
from competing reactions in which the â-ethyl carboni-
trile group is involved. Unfortunately, all attempts to
isolate complex 6 (or the other products) by column
chromatography failed. Nevertheless, this tentative
structural assignment of 6 seems plausible because of
the similar 31P NMR data of 6 and those of the
previously characterized, closely related P-methyl and
P-phenyl 2H-1,2-azaphosphole complexes (δ 31P ) 74.8,
(5) Review of nitrilium phosphanylide complexes: Streubel, R. Top.
Curr. Chem. 2002, 223, 91.
(6) Streubel, R.; Schiemann, U. J ones, P. G.; Tran Huy, N. H.;
Mathey, F. Angew. Chem. 2000, 112, 3845; Angew. Chem., Int. Ed.
2000, 39, 3686.
(7) Streubel, R.; Schiemann, U.; Tran Huy, N. H.; Mathey, F. Eur.
J . Inorg. Chem. 2001, 3175.
(8) For the first evidence of a noncoordinated 2H-1,2-azaphosphole
derivative: Streubel, R.; Wilkens, H.; Ruthe, F.; J ones, P. G. Tetra-
hedron 2000, 56, 21.
(9) For ab initio calculations on lithium 1,3-azaphospholide com-
plexes: Veszpre´mi, T.; Ma´trai, J .; Heinicke, J .; Kindermann, M. K. J .
Mol. Struct. (THEOCHEM) 2001, 538, 189.
(10) Recent article of cyclopentadienide complexes: Nyulaszi, L.; von
Rague Schleyer, P. J . Am. Chem. Soc. 1999, 121, 6872.
(11) Recent review of phospholide complexes: Mathey, F. Coord.
Chem. Rev. 1994, 137, 1.
(12) Recent review of phospholide complexes: Quin, L. D.; Quin, G.
S. In Phosphorus-Carbon Heterocyclic Chemistry: The Rise of a New
Domain; F. Mathey, F., Ed.; Pergamon: Amsterdam, 2001; Chapter
4.2.2, p 307.
1
1J (W,P) ) 249.1 Hz, P-Me and δ 31P ) 79.0, J (W,P) )
256.3 Hz, P-Ph).6
We knew from our recent studies16 that three-
component reactions using 2H-azaphosphirene com-
plexes, alkynes, and carbonitriles with strong π-donat-
ing substituents such as the triphenylphosphane-imino
substituent yield transient nitrilium phosphane-ylide
complexes that react more selectively than C-dialkyl-
(13) Espinosa Ferao, A.; Deshamps, B.; Mathey, F. Bull. Soc. Chim.
Fr. 1993, 130, 695.
(14) Tran Huy, N. H.; Vong, H.; Mathey, F. Organometallics 2002,
21, 336.
(15) Tran Huy, N. H. Unpublished results.
(16) Streubel, R.; Hoffmann, N.; Schiebel, H.-M. Ruthe, F.; J ones,
P. G. Eur. J . Inorg. Chem. 2002, 957.

Multifunctional 2H-1,2-Azaphosphole Complexes
Organometallics, Vol. 22, No. 26, 2003 5429
Sch em e 3. Un selective Syn th esis of
Sch em e 5. Gen er a tion a n d Rea ction of a
Mu ltifu n ction a l 2H-1,2-Aza p h osp h ole Com p lex 6
P r esu m a bly F or m ed 1,2-Aza p h osp h olid e Com p lex
2H-1,2-azaphosphole under the same reaction condi-
tions.20 Initial studies of cleavage reactions of the
exocyclic P-C bonds of 2H-1,2-azaphosphole complexes
11a and 11b showed instantaneous reactions of 11a ,b
with potassium tert-butanolate (KOtBu) at ambient
temperature (cf. refs 13. 14), accompanied by a color
change from bright yellow to dark red and leading to a
mixture of products. Repeating the reactions under the
same conditions (0 °C) but with a longer reaction time
and warming up to ambient temperature changed the
situation as shown by 31P NMR spectroscopic monitor-
ing. In each case, we now observed one major product
(ca. 75%), having a set of resonances of an AB-type, i.e.,
11a /KOtBu: δ ) 125.0 and 19.7 (12) and 11b/KOtBu:
δ ) 127.9 (4J (P,P) ) 7.6 Hz) and 15.4 (4J (P,P) ) 6.7
Hz) (12). In the latter case, a phosphorus-tungsten
coupling of 302.8 Hz was observed additionally, thus
lending further support to the structural assignment of
12 as the first 1,2-azaphospholide derivative, a situation
in which the phosphorus is expected to be approximately
sp2-hybridized and the negative charge is mainly local-
ized at the nitrogen (Scheme 5). Despite some minor
differences in the phosphorus NMR data, and although
we have no firm proof, we assume that the main
products were identical in both reactions. Subsequent
quenching of the reaction solutions with an excess of
methyl iodide led again to a color change from dark red
to dark yellow and the precipitation of a solid. The
formation of a new major product was spectroscopically
detected, i.e., 11b/KOtBu/MeI: δ ) 153.2 (A-part,
1J (W,P) ) 315.6 Hz) (13); the resonance of the B-part
was obscured by other resonances in the range 15-20
ppm. We conclude that a reaction of 12 with methyl
iodide probably led in the first step to N-methylation of
the azaphospholide nitrogen atom and metal salt forma-
tion (Scheme 5). Attempts to separate and purify
compound 13 by column chromatography have so far
failed; therefore, only phosphorus NMR data are avail-
able.
Sch em e 4. Selective Syn th esis of Mu ltifu n ction a l
2H-1,2-Aza p h osp h ole Com p lexes 11
amino-substituted derivatives. Therefore, we decided to
carry out a comparative study using the 7-phosphan-
orbornadiene complexes 3a ,15 3b,13 and 3c,d ,17 the
carbonitrile derivative 4b,18 and DMAD (5). Our as-
sumptions on the reaction course are shown in Scheme
4 and are based on the intermediate formation of the
terminal phosphanediyl complexes 9a -d , which then
react with carbonitriles to the nitrilium phosphane-ylide
complexes 10a -d . These then undergo [3+2] cycload-
dition reactions with DMAD, thus yielding finally 2H-
1,2-azaphosphole complexes 11a -d .
First attempts to liberate the 2H-1,2-azaphosphole
ligands from the complexes 11a -d using bis(diphen-
ylphosphino)ethane (DPPE) in o-xylene at 140 °C (cf.
ref 13) failed. This thermal stability of 11a -d is in
marked contrast to that of the corresponding bulky
P-bis(trimethylsilyl)methyl-substituted 2H-1,2-azaphos-
phole complex 11e,16 which yields the noncoordinated
To check the assumed reaction coursesexocyclic P,C-
bond cleavage and methylation reactionswe turned our
attention to a different but related N,P,C-heterocycle,
the 2H-1,3,2-diazaphosphole ring system. Additionally
we focused on mono-ester-functionalized derivatives,
thus (hopefully) avoiding side reactions. Therefore, we
synthesized tungsten complex 14 via a two-component
reaction using complex 3b and 2 equiv of dimethyl
cyanamide in toluene at 65 °C with a catalytic amount
of copper(I) chloride (Scheme 6). Interestingly, we
obtained only the 2H-1,3,2-regioisomer, thus also show-
ing that regioisomer formation largely depends on the
reaction temperature! (cf. ref 7).
(17) Marinetti, A.; Mathey, F.; Fischer, J .; Mitschler, A. J . Chem.
Soc., Chem. Commun. 1982, 667.
(18) Bittner, S.; Pomerantz, M.; Assaf, Y.; Krief, P.; Xi, S.; Witczak,
M. K. J . Org. Chem. 1988, 53, 1.
(19) Alijah, A.; Grigoleit, S.; Streubel, R.; Schoeller, W. W. J .
Organomet. Chem. 2002, 643-644, 223.
(20) Hoffmann, N.; Streubel, R. To be published.

5430 Organometallics, Vol. 22, No. 26, 2003
Streubel et al.
Ta ble 1. Ab In itio Geom etr ies (bon d len gth s), Rela tive En er gies, a n d NICS Va lu es of Lith iu m a n d
P ota ssiu m Aza p h osp h olid esa
a
[a]: rMP2(fc), [b]: rHF, [c]: GIAO-SCF//rMP2(fc)/6-311++g(2d,p), basis set [a,b]: 6311++g(2d,p) on all atoms. All geometries have
been characterized by a number of zero imaginary frequencies using GAUSSIAN 98. Energies are zero-point-corrected (sums of electronic
and zero-point energies).
Sch em e 6. Syn th esis of
Mon o-ester -F u n ction a lized
2H-1,3,2-Dia za p h osp h ole Com p lex 14
Sch em e 7. Gen er a tion a n d Meth yla tion of
In ter m ed ia tely F or m ed 1,3,2-Dia za p h osp h olid e
Com p lex 15
Adding small amounts of KOtBu (5 equiv) to a THF
solution of complex 14 at 0 °C (period of 80 min) and
warming to ambient temperature (18 h) resulted in a
color change from yellow to dark red and the formation
of complex 15 showing a 31P-resonance at 117.5 ppm
and a very low phosphorus-tungsten coupling of 172.2
Hz; such values are similar to those observed for
phospholide complexes (cf. ref 21). The crude product
mixture was analyzed with CI (methane) mass spectra
and the molecular ion was observed, thus providing
evidence for the nature of 15 as a new 1,3,2-diazaphos-
pholide complex (Scheme 7). Adding an excess of methyl
iodide to such a solution resulted in the formation of a
new major product with a 31P-resonance at 126.6 and a
phosphorus-tungsten coupling of 269.5 Hz. Surprised
by this resultswe had expected a significantly higher
phosphorus-tungsten coupling constant value for an
N-methylated species (!)swe decided to synthesize the
P-methyl-substituted 2H-1,3,2-diazaphosphole complex
16 using the same reaction protocol as for 14. In this
case only the 2H-1,3,2-regioisomer was isolated. Pure
complex 16 was then used as authentic sample, thus
providing strong evidence for the nature of the product
formed using the system KOtBu/methyl iodide and 14.
At the moment, we do not understand why P-methyla-
tion is preferred in this case.
It should be noted that N-methylation has been
described earlier for noncoordinated 1,3,2-diazaphos-
pholide derivatives with different C-substituents (cf. ref
22). Although the general quest of N- vs P-methylation
remains open, we take the outcome of this additional
study as further support for 1,2-azaphospholide forma-
tion in the case of the reactions of 11a ,b f 12.
Ab In itio Ca lcu la tion s. To shed more light on the
quest for the 1,2-azaphospholides, we also investigated
monomers of [LiC3H3NP]: the free 1,2-azaphospholide
(B), two isomers of lithium and potassium 1,2-azaphos-
pholides (C-F ), and, for comparison, the η5-lithium 1,3-
azaphospholide (A), first calculated by Veszpre´mi et al.,9
by ab initio calculations using HF and MP2/6-311++G-
(2d,p) levels of theory (Tables 1 and 2).
Compounds C and E have structures with equalized
C4-C5/C3-C4 bond lengths and SCF-NICS23,24 values
higher than (C) or similar to (E) that of the correspond-

Multifunctional 2H-1,2-Azaphosphole Complexes
Organometallics, Vol. 22, No. 26, 2003 5431
Ta ble 2. Ab In itio Geom etr ies (bon d a n gles, d ih ed r a l a n gles) of Lith iu m a n d P ota ssiu m Aza p h osp h olid esa
a
[a]: rMP2(fc), [b]: rHF, basis set [a,b]: 6311++g(2d,p) on all atoms. All geometries have been characterized by a number of zero
imaginary frequencies using GAUSSIAN 98. Energies are zero-point-corrected (sums of electronic and zero-point energies).
Ta ble 3. r MP 2(fc)-NP A Ch a r ge Distr ibu tion
ing lithium 1,3-azapholide isomer reported by Vesz-
pre´mi et al.9 The SCF-NICS value of C is slightly
enhanced as compared with A, and furthermore, C is
significantly lower in energy (A: +14.04 [kJ /mol]) (Table
1). According to the Li/K ring atom distances, species
C and E exhibit slightly displaced pentahapto-bonded
metal ions toward the N-C5 unit, indicating a negative
charge at nitrogen (Table 1). This corresponds with the
rMP2(fc)-NPA charges25 of C and E (Table 3). The
lithium and potassium ions are at distances of 1.80 Å
(A and C) and 2.56 Å (E) above the rings, calculated as
distances to the nonweighted mean of the heavy ring
atoms (the points of NICS calculation).
compound
charge at
A
B
C
D
E
F
Li
N
+0.91 Li
+0.91 +0.93
-0.87 -0.89 -1.05
+0.51 +0.59 +0.49
K
N
P
+0.96 +0.96
-0.89 -0.99
+0.55 +0.45
-0.58
+0.41
N
P
P
C2
C4
C5
-0.50 C3 -0.70 -0.72 -0.63 C3 -0.71 -0.64
-0.72 C4 -0.36 -0.38 -0.29 C4 -0.37 -0.30
-0.15 C5 -0.08 -0.14 -0.05 C5 -0.13 -0.06
values than the bare anion B, which is more or less
perfectly planar (Table 2). This finding seems to con-
tradict the observation by Goldfuss and Schleyer26 that
planar group 14 metallolyl anions C4H4EH- (E ) C, Si,
Ge, Sn, Pb) exhibited more negative NICSs than the
anions in the nonplanar geometries (E ) Si, Ge, Sn, Pb).
Discu ssion of Selected NMR Sp ectr oscop ic Da ta .
The analytical data including elemental analyses, MS
spectrometric data, and IR and NMR spectroscopic data
readily confirm the molecular structures of all com-
pounds reported here, which were separated and puri-
fied by column chromatography at low temperature and
subsequent crystallization in most cases. NMR data are
discussed here; for further analytical data see the
Experimental Section. The most significant NMR data
of the 2H-1,2-azaphosphole ring atoms of complexes
11a -d are collected in Table 4.
It is also noteworthy that A, C, and E are puckered
rings with a phosphorus in an envelope-type position
pointing away from the lithium (Table 2). Despite this
geometrical situation, A, C, and E have higher NICS
(21) Holand, S.; Charrier, C.; Mathey, F.; Fischer, J .; Mitschler, A.
J . Am. Chem. Soc. 1984, 106, 826.
(22) Karaghiosoff, K.; Klehr, H.; Schmidtpeter, A. Chem. Ber. 1986,
119, 410.
(23) von Rague´ Schleyer, P.; Maerker, C.; Dransfeld, A.; J iao, H.;
van Eikema Hommes, N. J . R. J . Am. Chem. Soc. 1996, 118, 6317.
(24) von R. Schleyer, P., et al. proposed the absolute isotropic
shielding at the “nonweighted mean of the heavy atom coordinates”
(nucleus-independent chemical shift) of a heterocycle as a measure of
the aromaticity of the ring. The points for the NICS value calculation
have been constructed using the following routine with GAUSSIAN
98 and GAUSS-View: Without changing angles or bond lengths of the
optimized geometry delete all substituents of the ring atoms and
replace every heteroatom by carbon. Let GAUSSIAN find the non-
weighted mean of this “dummy-ring” by a check of coordinates (using
the guess)only keyword). Place a ghost atom at the zero-point of the
coordinate system which is the center of mass of the dummy-ring. Let
GAUSSIAN create a z-matrix of both the dummy-ring including the
ghost atom and the optimized heterocycle. Add a ghost atom to the
z-matrix of the optimized heterocycle at the position that comes out of
the z-matrix of the dummy-ring. Perform a NMR calculation of the
optimized heterocycle including the ghost atom.
As expected, the 31P NMR resonances showed tung-
sten-phosphorus couplings, but no phosphorus-phos-
phorus couplings, as was recently observed in the case
of complex 11e.16 The 13C{1H} NMR spectra displayed
three resonances for the 2H-1,2-azaphosphole ring with
(26) Goldfuss, B.; von R. Schleyer, P. Organometallics 1997, 16,
(25) Reed, A. E.; Weinhold, F. J . Chem. Phys. 1983, 78, 1736.
1543.

5432 Organometallics, Vol. 22, No. 26, 2003
Streubel et al.
Ta ble 4. Selected NMR Sp ectr oscop ic Da ta a of th e 2H-1,2-Aza p h osp h ole Com p lexes 11a -e
compd
δ
31P2/7
1J (W,P)
δ
13C3
1+4J (P,C3)
δ
13C4
2+3J (P2/7,C4)
δ
13C5
2+3J (P,C5)
11a
11b
11c
79.6, 21.3
81.6, 20.6
76.2, 20.4
81.6, 20.9
85.8, 14.7
255.1
255.9
246.9
253.1
249.6
148.4
149.5
151.8
150.0
163.1
5.8
b
9.7
6.7
14.0
150.8
161.8
149.1
148.2
149.0
25.8, b
21.1, 2.4
26.2, b
26.1, b
48.1, 25.8
169.2
168.5
162.0
169.1
153.3
b
b
2.3
5.8
b
11d
11e16
a
b
In CDCl3; δ in ppm; J in Hz. Not resolved.
Sch em e 8. F r a gm en ta tion of th e Molecu la r
Ra d ica l Ca tion s of 11a -d
F igu r e 1. Molecular structure of 11a in the crystal
(ellipsoids represent 50% probability levels; hydrogen
atoms are omitted for clarity). Selected bond lengths [Å]
and angles [deg]: N2-C11 1.344(3), N1-P1-C9 94.34(10),
N1-P1-C6 105.04(11), C6-P1-C9 108.47(11), C11-N1-
P1 110.29(15), C10-C9-P1 106.34(16), C9-C10-C11 112.7-
(2), N1-C11-C10 115.1(2).
different phosphorus-carbon coupling constant magni-
tudes. The assignment of the resonances was made
according to a recent publication.16 Apart from the
typical small |J (31P,13C)| values for the C5 atoms, we
again observed that the phosphorus-carbon coupling
constant magnitude values of the C4 atoms were always
greater than those of the C3 atoms, although the latter
are directly bonded to phosphorus.
The 2H-1,2-azaphosphole rings of complexes 11a -d
showed no unusual bond lengths involving the ring
atoms and those atoms bonded externally to them. In
all cases the 2H-1,2-azaphosphole rings are approxi-
mately planar (largest mean deviation 0.047 Å in 11a ),
and the groups at the phosphorus (P1) in all cases adopt
the preferred relative orientation toward the tungsten
center and thus toward the ring, as already reported
for other structures of related phosphorus heterocycle
The signals of the molecular radical cations of 11a -d
range from lower 1% to 16% relative abundance. As a
general feature, significant intensities can be observed
for the triphenylphosphine fragment 17 and its degra-
dation products 18 and 19 in the lower mass range.27
In the upper range the spectra are dominated by
fragments that all display the typical isotopic distribu-
tion for tungsten. They are formed by successive loss of
carbon monoxide. The complete elimination of (penta-
carbonyl)tungsten was not observed. Elimination of CO
is influenced by the substituent R. Thus, fragment
radical cation 20 represents the base peak in the
spectrum of 11d , and it has a relative abundance of 92%
in the spectrum of 11a . The most stable decarbonylation
product of 11b and 11c is not 20 but the fragment
radical cation [M - 4CO]+• or [M - 2CO]+•, respectively.
In both cases fragment 20 is displayed with a relative
abundance of 14% for 11c and 5% for 11b (Scheme 8).
We were able to confirm the constitutions of com-
plexes 11a -d by X-ray single-crystal structure analyses
(Figures 1-4 and Tables 5-7).
complexes. The absolute torsion angles of N-C-Nendo
-
Pendo are not larger than 20.5° (in 11c); this should in
all cases enable electronic interactions between the ring
system and the substituent. It is remarkable that there
is no correlation between these values and the nature
of the P-substituents. In all cases the NPPh3 group
adopts an s-cis configuration with respect to the C-N(2)
bond.
Exp er im en ta l Section
Gen er a l P r oced u r es. All reactions and manipulations
were carried out under an atmosphere of deoxygenated dry
nitrogen, using standard Schlenk techniques with conventional
glassware, and solvents were dried according to standard
procedures. NMR spectra were recorded on a Bruker AC-200
spectrometer (200 MHz for 1H; 50.3 MHz for 13C; 81.0 MHz
for 31P) using [D]chloroform and [D6]benzene as solvent and
(27) Miller, J . Ph.D. Thesis, Cambridge University, 1996.

Multifunctional 2H-1,2-Azaphosphole Complexes
Organometallics, Vol. 22, No. 26, 2003 5433
F igu r e 4. Molecular structure of one of the two indepen-
dent molecules of 11d in the crystal (ellipsoids represent
50% probability levels; hydrogen atoms are omitted for
clarity). Selected bond lengths [Å] and angles [deg]: N2-
C12 1.344(2) 1.340(2)), N1-P1-C13 94.00(9) 93.94(8)),
N1-P1-C6 105.82(9) 105.10(9), C6-P1-C13 106.54(9)
106.06(9)), C12-N1-P1 110.80(13) 110.87(13)), C14-C13-
P1 107.37(14) 106.99(14)), C12-C14-C13 111.60(17)
112.51(17)), N1-C12-C14 115.47(16) 115.06(16).
F igu r e 2. Molecular structure of one of the two indepen-
dent molecules of 11b in the crystal (ellipsoids represent
30% probability levels; hydrogen atoms are omitted for
clarity). Selected bond lengths [Å] and angles [deg]: N2-
C13 1.345(3) (1.341(3)), N1-P1-C11 94.13(10) (94.32(10)),
N1-P1-C6 105.76(11) 105.17(11), C6-P1-C11 106.09(11)
108.01(11), C13-N1-P1 110.37(16) 110.30(16), C12-C11-
P1 107.01(17) (106.47(18)), C11-C12-C13 112.7(2)
(112.7(2)), N1-C13-C12 115.5(2) (115.5(2)).
solutions heated at 120 °C for 45 min with slow stirring. All
volatile components were removed in vacuo (ca. 0.01 mbar)
and the products separated by low-temperature column chro-
matography (SiO2, -10 °C, 10 × 2 cm, n-pentane/diethyl ether,
1:1). Evaporation of the second fractions yielded complexes
11a -d as yellow solids.
{[3,4-Bis(m eth oxyca r bon yl)-2-(2-cya n oeth yl)-5-(N-tr i-
p h en ylp h osp h on ioim in oyl)-2H -1,2-a za p h osp h ole-KP ]-
p en ta ca r bon yltu n gsten (0)} (11a ). Yield: 650 mg (78%); mp
1
152 °C (dec); H NMR (CDCl3) δ 1.51 (mc, 2H, CH2CH2CN),
2.23 (mc, 2H, CH2CH2CN), 3.77 (s, 3H, OCH3), 4.02 (s, 3H,
OCH3), 7.48 (mc, 7H, Ph), 7.58 (mc, 3H, Ph), 7.79 (mc, 5H, Ph);
2
13C{1H} NMR (CDCl3) δ 11.2 (d, J (P,C) ) 3.2 Hz, -CH2CH2-
1
CN), 30.8 (d, J (P,C) ) 9.8 Hz, -CH2CH2CN), 52.7 (s, OCH3),
52.8 (s, OCH3), 118.2 (d, 3J (P,C) ) 13.9 Hz, -CN), 126.1 (d,
1J (P,C) ) 100.7 Hz, ipso-Ph), 128.7 (d, 3J (P,C) ) 12.6 Hz, meta-
4
2
Ph), 132.9 (d, J (P,C) ) 2.9 Hz, para-Ph), 133.2 (d, J (P,C) )
10.1 Hz, ortho-Ph), 148.4 (d, 1J (P,C) ) 5.8 Hz, PCC), 150.8 (d,
2J (P,C) ) 25.8 Hz, PCC), 161.5 (d, 2J (P,C) ) 12.2 Hz, CO2-
CH3), 164.7 (d, 3J (P,C) ) 16.1 Hz, CO2CH3), 169.2 (s, PNC),
195.4 (d, 2J (P,C) ) 7.5 Hz, cis-CO), 198.9 (d, 2J (P,C) ) 23.3
Hz, trans-CO); 31P{1H} NMR (CDCl3) δ 21.3 (s, PPh3), 79.6 (s,
1J (W,P) ) 255.1 Hz); UV/vis (CH3CN) λ (lg ꢀ) ) 230 (4.99),
248 (4.63), 260 (4.44), 270 (4.18), 280 (3.98), 324 (3.90), 346
(3.87), 376 (3.63), 406 (3.36); IR (KBr) ν˜ 2075 (vs, CO), 1983
(vs, CO), 1945 (s, CO), 1921 (s, CO), 1907 (s, CO), 1742 (vs,
F igu r e 3. Molecular structure of 11c in the crystal
(ellipsoids represent 50% probability levels; hydrogen
atoms are omitted for clarity). Selected bond lengths [Å]
and angles [deg]: N2-C9 1.343(2), N1-P1-C7 94.26(8),
N1-P1-C6 105.15(9), C6-P1-C7 104.62(9), C9-N1-P1
110.41(13), C8-C7-P1 107.37(13), C7-C8-C9 112.40(17),
N1-C9-C8 115.30(16).
CO2), 1717 (vs, CO2) cm-1; MS (EI, 184W); m/z 853 (6) [M]+•
,
internal standard; shifts are given relative to external tet-
ramethylsilane (1H, 13C) and 85% H3PO4 (31P); only coupling
constant magnitudes are given. Electron impact (EI) (70 eV)
chemical ionization (CI) (ammonia or methane) and fast atom
bombardement (FAB) (Xenon) mass spectra were recorded on
a Finnigan MAT-8430 double-focusing mass spectrometer.
Infrared spectra were recorded on a Biorad FT-IR 165 (selected
797 (32) [M - 2CO]+, 713 (90) [M - 5CO]+, 262 (58) [PPh3],
183 (100) [PPh2]+, 73 (46) [Si(CH3)3]; MS (pos.-CI(NH3), 35Cl,
184W); m/z 958 (39) [M + H]+, 635 (74) [M + H - W(CO)5]+,
263 (100) [PPh3 + H]+. Anal. Calcd. for C33H25N3O9P2W: C,
46.45; H, 2.95; N, 4.92. Found: C, 47.69; H, 3.26; N, 4.96.
{[3,4-Bis(m eth oxycar bon yl)-2-(2-eth oxycar bon yleth yl)-
5-(N-tr iph en ylp h osp h on ioim in oyl)-2H-1,2-a za p h osp h ole-
KP ]p en ta ca r bon yltu n gsten (0)} (11b). Yield: 782 mg (87%);
mp 113 °C (dec); 1H NMR (CDCl3) δ 1.16 (t, 3J (H,H) ) 7.1 Hz,
3H, CO2CH2CH3), 1.70 (mc, 2H, PCH2CH2CO2Et), 2.22 (mc, 2H,
PCH2CH2CO2Et), 3.35 (s, 3H, OCH3), 3.92 (s, 3H, OCH3), 3.98
(mc, 2H, CO2CH2CH3), 7.38 (mc, 7H, Ph), 7.48 (mc, 3H, Ph),
7.70 (mc, 5H, Ph); 13C{1H} NMR (CDCl3) δ 14.1 (s, CH2CH3),
data given). Ultraviolett/vis spectra were recorded on
a
Hewlett-Packard HP 8452. Melting points were obtained on a
Bu¨chi 535 capillary apparatus. Elemental analyses were
performed using a Carlo Erba analytical gaschromatograph.
The κP-notation in the nomenclature is intended to differenti-
ate between P- and N-coordination of the appropriate hetero-
cycle to the metal.
Gen er a l P r oced u r e for th e P r ep a r a tion of Com p lexes
11a -d . To a solution of 7-phosphanorbornadiene complexes
3a -d (1 mmol each), dissolved in o-xylene (6 mL), carbonitrile
4b (1 mmol) and DMAD 5 (1 mmol) were added and the
2
1
27.8 (d, J (P,C) ) 4.3 Hz, PCH2CH2CO2Et), 30.0 (d, J (P,C) )
23.3 Hz, PCH2CH2CO2Et), 52.5 (s, OCH3), 52.6 (s, OCH3), 60.6
(s, OCH2CH3), 126.5 (d, 1J (P,C) ) 100.7 Hz, ipso-Ph), 128.6
(d, 3J (P,C) ) 12.6 Hz, meta-Ph), 132.6 (d, 4J (P,C) ) 2.8 Hz,
para-Ph), 133.2 (d, 2J (P,C) ) 10.1 Hz, ortho-Ph), 149.5 (s, PCC),

5434 Organometallics, Vol. 22, No. 26, 2003
Ta ble 5. Cr ysta l Da ta a n d Str u ctu r e Refin em en t of Com p lexes 11a -d
Streubel et al.
11a ‚3CH2Cl2
11b
11c
11d ‚3/2CH2Cl2
formula
Mr
C
36H31Cl6N3O9P2W
C35H30N2O11P2W
900.40
C31H24N2O9P2W
814.31
C37H29Cl3N2O9P2W
1003.77
1108.13
cryst size (mm)
cryst syst
space group
unit cell dimens
a (Å)
0.49 × 0.37 × 0.29
0.24 × 0.18 × 0.05
0.24 × 0.23 × 0.17
monoclinic
P21/n
0.47 × 0.42 × 0.34
triclinic
triclinic
triclinic
P1h
P1h
P1h
13.388(2)
13.458(2)
14.298(2)
68.213(6)
66.518(6)
77.182(6)
2185.8(6)
2
1.684
3.136
0.327-0.528
1092
13.0228(8)
13.5518(8)
24.1578(16)
77.715(5)
74.638(5)
63.712(5)
3663.4(4)
4
1.633
3.302
0.564-0.746
1784
9.0630(12)
21.616(3)
16.695(2)
90
99.522(5)
90
3225.6(8)
4
1.677
3.736
0.552-0.746
1600
133(2)
60
11.8945(11)
12.8234(12)
27.084(2)
100.416(4)
91.903(4)
100.960(4)
3979.1(6)
4
1.676
3.240
0.368-0.494
1980
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
Z
Dx (Mg m-3
)
µ (mm-1
)
transmns
F(000)
T(K)
133(2)
60
143(2)
60
133(2)
60
2θmax
no. of reflns
measured
unique
43 807
12 695
0.0355
516
77 673
21 328
0.0478
925
61 191
9451
0.0823
409
71 415
23 126
0.0232
984
Rint
no. of params
no. of restraints
Rw (F2, all reflns)
R (F, I >2σ(I))
S
78
144
285
144
0.0773
0.0289
1.06
0.0536
0.0275
0.92
0.0643
0.0264
1.03
0.0552
0.0230
1.02
max ∆F (e Å-3
)
1.81
1.61
2.14
1.15
Ta ble 6. Selected Bon d Len gth s [Å] of th e 2H-1,2-Aza p h osp h ole Com p lexes 11a -e; P -W, P -Cexo, a n d Rin g
Bon d s
compd
P-W
P-Cexo
P-C
P-N
CdC
NdC
C-C
11a
2.4947(7)
2.4932(7)
2.4891(7)
2.4941(6)
2.5036(5)
2.5110(5)
2.5384(4)
1.833(2)
1.826(2)
1.825(3)
1.821(2)
1.821(2)
1.826(2)
1.8312(16)
1.826(2)
1.825(2)
1.823(2)
1.8190(19)
1.829(2)
1.833(2)
1.8345(16)
1.685(2)
1.687(2)
1.684(2)
1.6932(16)
1.6825(16)
1.6851(16)
1.7005(14)
1.344(3)
1.331(3)
1.334(3)
1.338(3)
1.347(3)
1.343(3)
1.345(2)
1.321(3)
1.311(3)
1.311(3)
1.317(2)
1.317(3)
1.321(2)
1.311(2)
1.496(3)
1.495(3)
1.499(3)
1.501(2)
1.507(3)
1.499(3)
1.502(2)
11ba
11c
11d a
11e16
a
Two independent molecules.
°C (dec); 1H NMR (CDCl3) δ 1.67 (d, 1J (P,H) ) 7.6 Hz, 3H,
PCH3), 3.83 (s, 3H, OCH3), 4.01 (s, 3H, OCH3), 7.45 (mc, 7H,
Ph), 7.56 (mc, 3H, Ph), 7.76 (mc, 5H, Ph); 13C{1H} NMR (CDCl3)
δ 21.4 (d, 1J (P,C) ) 26.2 Hz, PCH3), 52.6 (s, OCH3), 52.7 (s,
OCH3), 126.9 (d, 1J (P,C) ) 100.7 Hz, ipso-Ph), 128.6 (d, 3J (P,C)
) 12.5 Hz, meta-Ph), 132.6 (d, 4J (P,C) ) 2.7 Hz, para-Ph),
133.3 (d, 2J (P,C) ) 10.2 Hz, ortho-Ph), 149.1 (d, 2J (P,C) ) 26.2
Ta ble 7. Tor sion An gles [d eg] of
2H-1,2-Aza p h osp h ole Com p lexes 11a -e
compd
torsion angle N-C-Nendo-Pendo
11a
2.4
3.2
11ba
1.6
11c
-20.5
1
2
11d a
2.0
Hz, PCC), 151.8 (d, J (P,C) ) 9.7 Hz, PCC), 162.0 (d, J (P,C)
3
-0.3
-18.9
) 2.3 Hz, PNC), 165.6 (d, J (P,C) ) 15.8 Hz, CO2CH3), 167.6
11e16
2
2
(d, J (P,C) ) 8.6 Hz, CO2CH3), 196.1 (d, J (P,C) ) 7.6 Hz, cis-
CO), 200.1 (d, 2J (P,C) ) 21.5 Hz, trans-CO); 31P{1H} NMR
(CDCl3) δ 20.4 (s, PPh3), 76.2 (s, J (W,P) ) 246.9 Hz); UV/vis
a
Two independent molecules.
1
(CH3CN) λ (lg ꢀ) ) 230 (4.99), 240 (4.83), 248 (4.64), 260 (4.44),
272 (4.07), 284 (3.85), 308 (3.80), 326 (3.85), 344 (3.82); IR
(KBr) ν˜ 2070 (vs, CO), 1989 (vs, CO), 1943 (s, CO), 1933 (s,
CO), 1916 (s, CO), 1747 (vs, CO2), 1724 (vs, CO2) cm-1; MS
(EI, 184W); m/z 814 (10) [M]+•, 758 (22) [M - 2CO]+, 730 (40)
[M - 3CO]+, 702 (95) [M - 4CO]+, 262 (98) [PPh3]+, 183 (100)
[PPh2]+. Anal. Calcd for C31H24N2O9P2W: C, 45.72; H, 2.97;
N, 3.44. Found: C, 45.58; H, 3.13; N, 3.35.
1
161.8 (dd, J (P,C) ) 21.1 Hz, 4J (P,C) ) 2.4 Hz, PCC), 161.9
2
(d, J (P,C) ) 3.0 Hz, CO2CH3), 165.1 (d, 3J (P,C) ) 15.3 Hz,
CO2CH3), 168.5 (s, PNC), 171.9 (d, 3J (P,C) ) 12.8 Hz, CO2Et),
195.8 (d, 2J (P,C) ) 7.6 Hz, cis-CO), 199.6 (d, 2J (P,C) ) 22.1
Hz, trans-CO); 31P{1H} NMR (CDCl3) δ 20.6 (s, PPh3), 81.6 (s,
1J (W,P) ) 249.8 Hz); UV/vis (CH3CN) λ (lg ꢀ) ) 230 (5.00),
248 (4.66), 260 (4.46), 270 (4.17), 282 (3.92), 294 (3.88), 326
(3.90), 368 (3.69), 390 (3.46); IR (KBr) ν˜ 2073 (vs, CO), 1962
(vs, CO), 1946 (s, CO), 1920 (s, CO), 1743 (vs, CO2), 1720 (vs,
CO2) cm-1; MS (EI, 184W); m/z 899 (2) [M - H]+•, 872 (60) [M
- CO]+, 844 (100) [M - 2CO]+, 760 (8) [M - 5CO]+, 262 (96)
[PPh3], 183 (60) [PPh2]+. Anal. Calcd for C35H30N2O11P2W: C,
46.69; H, 3.36; N, 3.11. Found: C, 46.67; H, 3.44; N, 3.07.
{[3,4-Bis(m e t h oxyca r b on yl)-2-m e t h yl-5-(N -t r ip h e n -
ylp h osp h on ioim in oyl)-2H -1,2-a za p h osp h ole-KP ]p en t a -
ca r bon yltu n gsten (0)} (11c). Yield: 660 mg (81%); mp 161
{[3,4-Bis(m e t h oxyca r b on yl)-2-p h e n yl-5-(N -t r ip h e n -
ylp h osp h on ioim in oyl)-2H -1,2-a za p h osp h ole-KP ]p en t a -
ca r bon yltu n gsten (0)} (11d ). Yield: 460 mg, (58%); mp 67
1
°C (dec); H NMR (CDCl3) δ 3.72 (s, 3H, OCH3), 3.91 (s, 3H,
OCH3), 7.08 (mc, 5H, Ph), 7.40 (mc, 3H, Ph), 7.45 (mc, 7H, Ph),
7.78 (mc, 5H, Ph); 13C{1H} NMR (CDCl3) δ 52.5 (s, OCH3), 52.8
1
(s, OCH3), 126.8 (d, J (P,C) ) 100.6 Hz, ipso-Ph(Ph3P)), 128.0
2
3
(d, J (P,C) ) 10.3 Hz, ortho-Ph), 128.8 (d, J (P,C) ) 12.6 Hz,

Multifunctional 2H-1,2-Azaphosphole Complexes
Organometallics, Vol. 22, No. 26, 2003 5435
meta-Ph(Ph3P)), 130.2 (s, para-Ph), 130.4 (d, 3J (P,C) ) 12.4
Hz, meta-Ph), 132.7 (d, 4J (P,C) ) 2.8 Hz, para-Ph(Ph3P)), 133.4
(d, 2J (P,C) ) 10.2 Hz, ortho-Ph(Ph3P)), 134.6 (d, 1J (P,C) ) 39.7
Hz, ipso-Ph), 148.2 (d, 2J (P,C) ) 26.1 Hz, PCC), 150.0 (d,
1J (P,C) ) 6.7 Hz, PCC), 162.0 (d, 3J (P,C) ) 14.8 Hz, CO2CH3),
petrol ether/diethyl ether, 1:2). Evaporation of the second
fractions yielded complex 16 as pale yellow solid. Yield: 400
mg (78%); 1H NMR (CDCl3) δ 1.8 (d, 3H, 2J (P,H) ) 6.8 Hz,
PCH3), 3.04 (s, 12H, N(CH3)2); 13C{1H} NMR (CDCl3) δ 25.0
(d, 1J (P,C) ) 26.8 Hz, PCH3), 41.3 (s, N(CH3)2), 162.3 (d, 2J (P,C)
3
2
2
165.5 (d, J (P,C) ) 16.2 Hz, CO2CH3), 169.1 (d, J (P,C) ) 5.8
Hz, PNC), 196.3 (d, 2J (P,C) ) 7.5 Hz, cis-CO), 199.9 (d, 2J (P,C)
) 22.6 Hz, trans-CO); 31P{1H} NMR (CDCl3) δ 20.9 (s, PPh3),
) 6.2 Hz, N-CdN), 197.1 (d, J (P,C) ) 8.5 Hz, cis-CO), 201.1
(d, 2J (P,C) ) 23.0 Hz, trans-CO); 31P{1H} NMR (CDCl3) δ 126.5,
1J (W,P) ) 266.0 Hz; MS (EI, 184W) m/z 510 (69) [M]+, 483 (41)
[M - CO]+, 369 (100) [M - 5CO]+. Anal. Calcd for C12H15O5-
PN4W: C, 28.26; H, 2.96. Found: C, 28.31; H, 3.03.
1
81.6 (s, J (W,P) ) 253.1 Hz); UV/vis (CH3CN) λ (log ꢀ) ) 218
(4.96), 226 (4.99), 248 (4.68), 260 (4.50), 270 (4.28), 276 (4.16),
324 (3.87), 340 (3.87), 360 (3.76); IR (KBr) ν˜ 2071 (s, CO), 1962
(s, CO), 1935 (vs, CO), 1913 (vs, CO), 1742 (s, CO2), 1722 (s,
CO2) cm-1; MS (EI, 184W); m/z 876 (12) [M]+•, 848 (10) [M -
CO]+, 820 (28) [M - 2CO]+, 792 (54) [M - 3CO]+, 764 (46)
[M-4CO]+, 736 (100) [M - 5CO]+, 262 (68) [PPh3]+, 183 (64)
[PPh2]+, 77 (4) [Ph]+. Anal. Calcd for C36H26N2O9P2W: C, 49.34;
H, 2.99; N, 3.20. Found: C, 49.23; H, 3.10; N, 3.12.
Syn th esis of Com p lex 16 via Rea ction of 14 w ith th e
System KOtBu /MeI. Complex 14 (0.2 g, 0.29 mmol) was
dissolved in 4 mL of THF and cooled to 0 °C, and 0.039 g
(0.0345 mmol) of KOtBu was added (the addition was done
four times, after 20 min each). After warming to ambient
temperature (in 18 h) and additional stirring for 5 h, 1.5 mL
of methyliodide was added and the solution stirred for 15 h at
ambient temperature. All volatile components were removed
in vacuo (ca. 0.01 mbar) and the products separated by low-
temperature column chromatography (SiO2, -10 °C, 10 × 2
cm, petrol ether/diethyl ether, 3:7). Evaporation of the second
fraction yielded complex 16 as a pale yellow solid. Yield: 76
mg (51%).
{[4,5-Bis(d im et h yla m in o)-2-(2-et h oxyca r b on ylet h yl)-
2H -1,3,2-d ia za p h osp h ole -KP ]p e n t a ca r b on ylt u n gst e n -
(0)} (14). To a solution of 7-phosphanorbornadiene complex
3b (1 mmol) and copper(I) chloride (0.4 mmol), dissolved in
toluene (3 mL), was added dimethyl cyanamide (3 mmol). The
solution was heated at 65 °C for 60 min with slow stirring.
All volatile components were removed in vacuo (ca. 0.01 mbar)
and the products separated by column chromatography (SiO2,
20 °C, 10 × 2 cm, petrol ether/diethyl ether, 1:2). Evaporation
of the second fractions yielded complex 14 as pale yellow solid.
X-r a y Cr ysta llogr a p h ic An a lyses. For crystal data and
structure refinement of complexes 11a -d see Table 2. The
data were registered with
a Bruker SMART 1000 CCD
diffractometer; absorption corrections were based on SADABS.
The structures were solved by the heavy atom method and
refined anisotropically by full-matrix least-squares on F2.28
Hydrogen atoms were included using a riding model or rigid
methyl groups.
1
2
Yield: 440 mg (74%); H NMR (CDCl3) δ 1.18 (t, 3H, J (H,H)
) 7.14 Hz, CH3(Et)), 2.02 (ABX, 2H, CH2), 2.35 (ABX, 2H,
CH2), 2.99 (s, 12 H, N(CH3)2), 4.03 (q, 2H, OCH2); 13C NMR
(CDCl3) δ 14.1 (s, CH3(Et)), 27.7 (s, CH2), 32.3 (d, 1J (P,C) )
24.4 Hz, CH2), 40.8 (d, N(CH3)2, 2J (P,C) ) 27.5 Hz), 61.2 (s,
OCH2), 162.9 (d, 2J (P,C) ) 5.3 Hz, N-CdN), 172.3 (d, 3J (P,C)
Ack n ow led gm en t. We are grateful to the Fonds der
Chemischen Industrie and the Deutsche Forschungs-
gemeinschaft for support of this research and to Mr. A.
Weinkauf for X-ray data collection.
2
) 10.6 Hz, CO2), 196.6 (d, J (P,C) ) 8.2 Hz, cis-CO), 200.5 (d,
2J (P,C) ) 24.1 Hz, trans-CO); 31P{1H} NMR (CDCl3) δ 127.9
(s, 1J (W,P) ) 268.2 Hz); MS (184W) m/z 597 (23) [M]+, 568 (100)
[M - CO]+, 457 (67) [M - 5CO]+. Anal. Calcd for C16H21O7-
PN4W: C, 32.23; H, 3.55. Found: C, 31.96; H, 3.38.
Su p p or tin g In for m a tion Ava ila ble: For 11a -d , tables
of crystal data and structure refinement details, atomic
coordinates, displacement parameters, and bond distances and
angles. This material is available free of charge via the
Internet at http://pubs.acs.org.
{[4,5-Bis(d im eth yla m in o)-2-(2-m eth yl)-2H-1,3,2-d ia za -
p h osp h ole-KP ]p en ta ca r bon yltu n gsten (0)} (16). To a solu-
tion of 7-phosphanorbornadiene complex 3c (1 mmol) and
copper(I) chloride (0.4 mmol), dissolved in toluene (3 mL), was
added dimethyl cyanamide (3 mmol). The solution was heated
at 65 °C for 60 min with slow stirring. All volatile components
were removed in vacuo (ca. 0.01 mbar) and the products
separated by column chromatography (SiO2, 20 °C, 10 × 2 cm,
OM030547X
(28) Sheldrick, G. M. SHELXL-97, program for crystal structure
refinement; University of Go¨ttingen, 1997.