Reactions with electrophiles control isomerization from η5(π)- to η1(P)-coordination of phosphinyl-substituted benzophospholide ligands

Article abstract of DOI:10.1021/om020404v

The Ph₂P-functionalized phosphoniobenzo[c]phospholide 5 reacts with [Cr(CO)₅(cyclooctene)] and [Cr(CO)₃(naphthalene)] under site-selective n(P)-complexation at the Ph₂P moiety and π-complexation at the five-membered heterocycle, respectively, to give complexes 6 and 7, which were characterized by spectroscopic data and an X-ray diffraction study of 6. The attack of electrophiles E (E = alkyl^-, Ag^-, S, BH₃) on the π-complex 7 occurs at the pendant Ph₂P substituent to give unstable quaternization products that were in some cases detectable by NMR. The initial products decay either via decomplexation to metal-free quaternization products (for E = alkyl⁺) or via a combination of decomplexation/isomerization reactions to give mixtures of free quaternization products and complexes 10a and 13a containing a Cr-(CO)₄ unit that is chelated by a n(P)-coordinated benzophospholide moiety and an adjacent sulfur atom (for E = S) or a BH-σ-bond (for E = BH₃). These products as well as their tungsten analogues 10b and 13b were likewise accessible from the appropriate ligands and [M(CO)₄-(norbornadiene)], and 10a,b and 13b were isolated from these reactions and characterized by spectroscopic and X-ray diffraction studies. The course of the studied reactions of 7 with electrophiles suggests that the destabilization of the primary quaternization products is controlled by increased weakening of the π-donor power of the ligand with increasing phosphonium character of the substituents at the benzophospholide moiety. The observed spontaneous π(η⁵)/κ²-P,σ-BH-coorainatioii isomerization of a benzophospholide implies that the unusual coordination mode through a phosphorus lone pair and a BH-σ-bond is thermodynamically preferable to π-coordination through the five-membered ring.

Full text of DOI:10.1021/om020404v

5182
Organometallics 2002, 21, 5182-5189
Rea ction s w ith Electr op h iles Con tr ol Isom er iza tion fr om
η5(π)- to η1(P )-Coor d in a tion of P h osp h in yl-Su bstitu ted
Ben zop h osp h olid e Liga n d s
Zoltan Bajko, J o¨rg Daniels, Dietrich Gudat,* Stefan Ha¨p, and Martin Nieger
Institut fu¨r Anorganische Chemie der Universita¨t Bonn, Gerhard-Domagk-Strasse 1,
53121 Bonn, Germany
Received May 20, 2002
The Ph2P-functionalized phosphoniobenzo[c]phospholide 5 reacts with [Cr(CO)5(cyclooctene)]
and [Cr(CO)3(naphthalene)] under site-selective n(P)-complexation at the Ph2P moiety and
π-complexation at the five-membered heterocycle, respectively, to give complexes 6 and 7,
which were characterized by spectroscopic data and an X-ray diffraction study of 6. The
attack of electrophiles E (E ) alkyl+, Ag+, S, BH3) on the π-complex 7 occurs at the pendant
Ph2P substituent to give unstable quaternization products that were in some cases detectable
by NMR. The initial products decay either via decomplexation to metal-free quaternization
products (for E ) alkyl+) or via a combination of decomplexation/isomerization reactions to
give mixtures of free quaternization products and complexes 10a and 13a containing a Cr-
(CO)4 unit that is chelated by a n(P)-coordinated benzophospholide moiety and an adjacent
sulfur atom (for E ) S) or a BH-σ-bond (for E ) BH3). These products as well as their tungsten
analogues 10b and 13b were likewise accessible from the appropriate ligands and [M(CO)4-
(norbornadiene)], and 10a ,b and 13b were isolated from these reactions and characterized
by spectroscopic and X-ray diffraction studies. The course of the studied reactions of 7 with
electrophiles suggests that the destabilization of the primary quaternization products is
controlled by increased weakening of the π-donor power of the ligand with increasing
phosphonium character of the substituents at the benzophospholide moiety. The observed
spontaneous π(η5)/κ2-P,σ-BH-coordination isomerization of a benzophospholide implies that
the unusual coordination mode through a phosphorus lone pair and a BH-σ-bond is
thermodynamically preferable to π-coordination through the five-membered ring.
In tr od u ction
a further metal-binding site.4 Owing to these properties,
metallocene analogue phospholyl complexes (phospha-
metallocenes) have been used as attractive ligands in
catalytic processes involving soft transition metals.4,5
During our investigations of the chemistry of benzan-
nulated phospholide derivatives II-IV,6 we have shown
that the presence of positively charged phosphonio
substituents renders the ligands weaker donors but
enhances at the same time the π-acceptor power of the
heteroaromatic ring.7 The zwitterionic benzophospholide
1 displays therefore a balanced coordination behavior
and may bind to transition metal atoms via both the
phosphorus lone pair (n(P)-coordination, 2) and the
aromatic π-electron system, thus forming a stable half-
sandwich complex 3 that is a structural analogue of an
η5-indenyl complex (Scheme 1).7c Cationic bisphospho-
niobenzophospholides (IV) readily bind metal atoms via
Heterocyclopentadienyls I are analogues of cyclopen-
tadienyl (Cp) anions that are formally obtained when a
CH moiety is replaced by an isoelectronic fragment E
containing a different element of group 13-15 (E ) BR-,
SiR, GeR, N, P, As, Sb).1-3 Transition metal complexes
of I mimic the well-known Cp complexes, but exhibit
modulated metal reactivities due to the different elec-
tronic properties of the individual heterocyclic ligands,
and in the context of the wide use of Cp complexes in
catalysis and organometallic synthesis, the exploration
of their chemistry is currently receiving considerable
interest.1-3 A substantial amount of work in this area
has been dedicated to complexes of phospholides (I, E
) P) whose electronic resemblance to Cp ligands is
particularly close due to the very similar electronega-
tivities of C and P, respectively.2,3 Notwithstanding this
similarity, phospholides are distinguished by their
enhanced π-acceptor properties3 and the presence of an
additional lone pair at phosphorus, which may serve as
(4) Mathey, F. J . Organomet. Chem. 2002, 646, 15.
(5) Weber, L. Angew. Chem., Int. Ed. 2002, 41, 563.
(6) Gudat, D.; Bajorat, V.; Ha¨p, S.; Nieger, M.; Schro¨der, G. Eur. J .
Inorg. Chem. 1999, 1169.
* Corresponding author. Fax: ++49 (0)228 73 53 27. E-mail:
dgudat@uni-bonn.de.
(7) (a) Gudat, D.; Schrott, M.; Nieger, M. J . Chem. Soc., Chem.
Commun. 1995, 1541. (b) Gudat, D.; Holderberg, A. W.; Korber, N.;
Nieger, M.; Schrott, M.; Z. Naturforsch. 1999, 54, 1244. (c) Gudat, D.;
Ha¨p, S.; Szarvas, L.; Nieger, M. Chem. Commun. 2000, 1637. (d) Gudat,
D.; Ha¨p, S.; Bajorat, V.; Nieger, M. Z. Anorg. Allg. Chem. 2001, 627,
1119. (e) Ha¨p, S.; Nieger, M.; Gudat, D.; Betke-Hornfeck, M.; Schramm,
D. Organometallics 2001, 20, 2679. (f) Gudat, D.; Ha¨p, S.; Nieger, M.
J . Organomet. Chem. 2002, 643, 181.
(1) ER ) BR-, SiR, GeR, N, P: (a) Review: A. P. Sadimenko, Adv.
Heterocycl. Chem. 2001, 79, 115, and references therein.
(2) ER ) N, P, As, Sb: Nief, F. Eur. J . Inorg. Chem. 2001, 891.
(3) ER ) P: Mathey, F. Coord. Chem. Rev. 1994, 137, 1. (b) Dillon,
K. B.; Mathey, F.; Nixon, J . F. Phosphorus: The Carbon Copy; J ohn
Wiley: Chichester 1998, and references therein.
10.1021/om020404v CCC: $22.00 © 2002 American Chemical Society
Publication on Web 10/31/2002

Reactions with Electrophiles
Ch a r t 1
Organometallics, Vol. 21, No. 24, 2002 5183
Sch em e 2a
Sch em e 1a
a
(i) [Cr(CO)5(coe)], (ii) [Cr(CO)3(napht)].
by a single-crystal X-ray diffraction study. The selective
coordination of the Cr(CO)5 unit to the Ph2P group in 6
is in accord with the easier steric accessibility and
enhanced nucleophilicity9 of this site. Comparison of the
carbonyl regions in the IR spectra of 6 (νj ) 2058, 1932
cm-1) and 2 (νj ) 2064, 1942, 1913 cm-1 7c) reveals slight
red-shifts of the highest energy modes of the former,
which is in accord with a lower π-acceptor capability of
a Ph2P as compared to a benzophospholide moiety. Key
to the constitution assignment of π-complex 7 is the
large negative coordination shift for the signal of the
ring phosphorus atom (∆δ31P ) -175.5), which is of
similar magnitude to that in 3 (∆δ31P ) -157.8); in
contrast, the chemical shift of the PPh2 moiety deviates
little from that in 5 (∆δ31P ) +3) and remains in the
characteristic region of phosphines. Further worth
mentioning is the chemical inequivalence of the two
phenyl rings in the PPh2 moiety, which is clearly visible
in the 13C NMR spectrum and owes to the planar
chirality of the complex. The similarity of the carbonyl
stretching modes of 7 (νj ) 1927, 1844, 1830 cm-1) and
3 (νj ) 1925, 1835, 1826 cm-1 7c) further substantiates a
close resemblance of the geometric and electronic struc-
tures of both complexes.
Subsequent reaction of 7 with equimolar amounts of
methyl iodide and benzyl bromide afforded cations 8a ,b
besides minor amounts (<20%) of complex 6 (Scheme
3). The products were identified by comparison of their
31P NMR data (Table 1) with those of authentic samples;
the formation of further chromium-containing products
can be inferred even though none was positively identi-
fied. Since monitoring the progress of the reaction by
31P NMR disclosed no further observable intermediates,
the formation of 8a ,b suggests that a hypothetical
cationic π-complex formed by quaternization of the PPh2
moiety of 7 is unstable and decays immediately with
loss of the Cr(CO)3 fragment; the generation of 6 as
byproduct arises presumably from subsequent transfer
of two CO ligands to unreacted starting material.
Attributing the instability of postulated η5-complexes
of 8a ,b to low π-nucleophilicity of a cationic ligand,9,10
we reasoned that more stable complexes should be
obtained if quaternization of the Ph2P moiety in 7 was
carried out with sulfur or BH3‚THF to give products
with neutral thioxophosphorane or phosphine-borane
ligands, respectively. In contrast to this anticipation,
reaction of 7 with a stoichiometric amount of sulfur gave
a
(i) [Cr(CO)5(coe)], (ii) [Cr(CO)3(napht)].
the phosphorus lone pair,7a,b,e and their π-acceptor
character is sufficient to allow the use of these ligands
in hydroformylation catalysts.7e Despite a general pref-
erence of n(P)-coordination for these cations,7 the recent
isolation of the η2-complex 48 proves that formation of
π-complexes is in principle feasible. At this point we
became interested in establishing if cations of type IV
may also form yet unknown η5-complexes that could be
potentially useful as novel π-acceptor ligands. Having
synthesized the phosphinyl-substituted zwitterion 5,6
we reasoned that the target compounds might be
accessible by conversion of 5 into a η5-complex similar
to the case of 3 and subsequent quaternization of the
pendant Ph2P moiety. We report here on the results of
these experiments as well as the unexpected outcome
of similar reactions of the formed π-complex with sulfur
and BH3‚THF.
Resu lts a n d Discu ssion
Ch em ica l Rea ction s a n d Sp ectr oscop ic Stu d ies.
The phosphinyl-substituted zwitterion 5 offers with the
lone pairs of the two- and three-coordinate phosphorus
atoms and the π-electrons of the fused ring system in
principle three different metal-binding sites. To survey
if, as in the case of 1,7c site-selective complex formation
is feasible, we reacted 5 with equimolar [Cr(CO)5(coe)]
and [Cr(CO)3(napht)] (coe ) cyclooctene, napht ) naph-
thalene), respectively. Both reactions proceeded accord-
ing to a 31P NMR survey with quantitative formation
of a single phosphorus-containing species. The products
were isolated after precipitation with hexane and re-
crystallization from toluene, and their nature as com-
plexes 6 and 7 (Scheme 2) was established by microan-
alytical and spectroscopic data (cf. Table 1) and for 6
(9) Ha¨p, S.; Szarvas, L.; Nieger, M.; Gudat, D. Eur. J . Inorg. Chem.
2001, 2763.
(8) Gudat, D.; Ha¨p, S.; Nieger, M. Z. Anorg. Allg. Chem. 2001, 627,
(10) Gudat, D. Coord. Chem. Rev. 1997, 173, 71, and references
2269.
therein.

5184 Organometallics, Vol. 21, No. 24, 2002
Bajko et al.
Ta ble 1. 31P NMR Da ta of P h osp h on ioben zop h osp h olid e Der iva tives 5-14 (a t 30 °C, in THF ) (E d en otes a
su bstitu en t a t th e exocyclic P h 2P m oiety, a n d M a η5-coor d in a ted m eta l fr a gm en t on th e
ben zop h osp h olid e m oiety)
E
M
δ
31P (-PA-)
δ
31P (E-PMPh2)
δ
31P (-PXPh3)
J AM [Hz]
J AX [Hz]
J MX [Hz]
5a
6
7
8a
218.4
234.0
47.0
234.7
237.1
228.3
280.6
227.6b
230.8
54.0
-21.4
33.0
-17.7
16.4
16.3
35.0
14.7
15.5
21.3
12.3
15.0
16.1
97.2
88.4
7.9
92
92.8
88.4
82.4
134.2
61.0
92
80.1
88.7
1.9
8.3
5.1
8.3
8.3
8.1
Cr(CO)5
Cr(CO)3
Me+
CH2Ph+
S
S-Cr(CO)4
S-W(CO)4
BH3
8b
9a
10a
10b
11a
12
13a
13b
14
27.4c
9.4
11.1
13.2
15.5
22.0
121.0
86.1
35.6
64.5
88.4
64.9
6.4
6.4
BH3
Cr(CO)3
BH3-Cr(CO)4
BH3-W(CO)4
BH3-Cr(CO)3(THF)
263.4
217.2d
279.0
1.3
-15.2
14.7
15.7
138.6
195.2
62.3
65.0
7.6
7.0
a
b1
c2
d1
Data from ref 9.
J
242 Hz.
J
9 Hz.
J
264 Hz.
WPA
WPA
WPB
Sch em e 3a
complexes 12 and 13a (Scheme 5). Prolonged reaction
times lead to complete conversion of 12 into 11 and 13a .
The assignment of 12 as a π-complex was in the first
place deduced from the similar 31P NMR shift of the
endocyclic phosphorus atom as compared to 7 (cf. Table
1) and was further confirmed by independent synthesis
of a mixture of 12 and 13a by reaction of zwitterion 11
with excess [Cr(CO)3(napht)]. Assignment of the con-
stitution of 13a as a complex with a n(P)-coordinated
benzophospholide was suggested by the substantial
deshielding of the ring phosphorus atom (∆δ31P )
+216.4 vs 7) and further corroborated by the observa-
tion that this complex was also formed in approximately
25% yield (from integration 31P NMR spectra) by reac-
tion of equimolar amounts of [Cr(CO)4(nbd)] and the
borane adduct 11 (no 12 was detectable under these
conditions); the low yield of complex contrasts with the
smooth formation of 10a from 9 and the chromium
complex, but is in accord with the reputedly low stabili-
ties of other known borane-transition metal com-
plexes.11 Addition of [Cr(CO)4(nbd)] in large excess
increased the yield of 13a , but favored also formation
of 6 as byproduct and rendered separation of the
mixture and isolation of 13a unfeasible. A higher
selectivity was observed in the reaction of 11 and
[W(CO)4(nbd)]. Extensive formation of the tungsten
complex 13b occurred with only 2 equiv of the olefin
complex, and the product was readily isolated and
characterized by spectroscopic and X-ray diffraction
studies.
The 31P NMR spectrum of 13b displays an AMX
pattern similar to that of 13a . The resonances of the P
atoms in the ring and the phosphine-borane moiety
exhibit small negative coordination shifts (∆δ31P )
-14.5 (-P-), -10.8 (P-B) vs 11), and n(P)-coordination
of the ring phosphorus atom is clearly evidenced by a
characteristic set of 183W satellites (1J WP ) 264 Hz). The
1H NMR spectrum displays a single broad signal (δ1H
) -1.33) attributable to the BH3 group, which is
likewise more shielded than that in 11 (δ1H ) 1.41) and
changes under 11B decoupling into a sharp multiplet.
Application of additional selective 31P decoupling al-
a
8a : R ) Me, X ) I; 8b: R ) PhCH2, X ) Br.
Sch em e 4
likewise no evidence for a stable η5-complex, but af-
forded a mixture of thioxophosphorane 9 and chromium
complex 10a as the only phosphorus-containing prod-
ucts (Scheme 4). While 9 was identified by comparison
of its 31P NMR data with an authentic sample, the
identity of complex 10a was confirmed by its indepen-
dent synthesis from 9 and [Cr(CO)4(nbd)] (nbd ) nor-
bornadiene); a similar reaction with [W(CO)4(nbd)]
afforded also the tungsten complex 10b. The chelating
κ2-P,S-coordination of the benzophospholide ligands in
10a ,b was deduced from NMR data (Table 1) and
confirmed by X-ray diffraction studies. Key spectroscopic
features that substantiate a shift from π- to n(P)-
coordination include the substantial deshielding of the
ring phosphorus atoms (∆δ31P ) +233.6 (10a ), +180.6
(10b) vs 7), and for 10b the presence of 183W satellites
with couplings of 1J WP ) 242 Hz for the endocyclic and
2J WP ) 9 Hz for the PdS phosphorus atom.
Reaction of π-complex 7 with BH3‚THF afforded
according to a 31P NMR survey a mixture of three
phosphorus-containing products. Each species gave rise
to an AMX-type pattern whose most shielded signal
consisted of a broad line without resolved fine structure.
Such line broadening is a typical consequence of spin
coupling to an adjacent quadrupolar boron nucleus, and
we thus assign all products as Lewis-acid/base adducts
formed by attachment of BH3 to the Ph2P moiety. One
product was readily identified as known zwitterion 119
by comparison of its 31P NMR data with an authentic
sample, and the remaining ones were appointed as novel
(11) (a) McNamara, W. F.; Duesler, E. N.; Paine, R. T.; Ortiz, J . V.;
Ko¨lle, P.; No¨th, H. Organometallics 1986, 5, 380. (b) Shimoi, M.; Nagai,
S.; Ichikawa, M.; Kawano, Y.; Katoh, K.; Uruichi, M.; Ogino, H. J . Am.
Chem. Soc. 1999, 121, 11704. (c) Kakizawa, T.; Kawano, Y.; Shimoi,
M. Organometallics 2001, 20, 3211.

Reactions with Electrophiles
Organometallics, Vol. 21, No. 24, 2002 5185
Sch em e 5
Ch a r t 2
2
lowed the assignment of the J P-B-H (9.0 Hz) and
2J P-W-H (5.1 Hz) couplings. The increase of the latter
4
compared to J P-C-P-B-H ) 2.5 in 12 and the observa-
tion of 183W satellites with J WH ) 14 Hz clearly confirm
1
the attachment of the BH3 unit to the metal. In view of
the X-ray data (see below) which disclose the presence
of one coordinated and two terminal BH bonds in the
crystal, the chemical equivalence of the BH3 hydrogens
in solution 1H NMR spectra (low-temperature spectra
gave no evidence for a decoalescence down to -80 °C)
suggests a fluxional molecular structure in which rota-
tion of the BH3 moiety induces rapid scrambling of
coordinated and terminal BH bonds. Similar dynamic
effects have been previously observed for other transi-
tion metal complexes of σ-BH-coordinated borane/Lewis-
base adducts.11
Further 31P NMR studies revealed that the formation
of chromium complex 13a in the reaction of 11 with [Cr-
(CO)3(napht)] was preceded besides 12 by that of a
further transient borane complex which gave rise to an
AMX pattern with chemical shifts similar to 13a (Table
1). Regarding that this intermediate was observable
only when the reaction was conducted in THF, its
molecular structure is tentatively assigned as chelate
complex 14 (Scheme 5).
unstable heterobimetallic complexes which decomposed
during prolonged storage or attempts toward workup
of the reaction mixture. Partial constitutional assign-
ment was feasible from low-temperature 31P and 109Ag
NMR data. The 31P NMR spectra show three groups of
signals centered around 49, 21, and 1.5 ppm attributable
to the phosphorus atoms of benzophospholide, triphen-
ylphosphonio, and diphenylphosphinyl moieties. The
chemical shift of the ring phosphorus atom suggests that
the π-coordinated Cr(CO)3 moiety is still present, and
a characteristic splitting by spin coupling to 107/109Ag
nuclei on the signal attributable to the phosphorus in
the Ph2P moiety indicates coordination of Ag+ at this
1
site (a 2D 31P,109Ag HMQC spectrum yielded J 109Ag,P
) 590 Hz and δ109Ag ) 668). The observed data are
compatible with the presence of a 1:1 (15a , Chart 2) or
a 2:1 (15b) complex, or a mixture of both, but the poor
resolution precluded a more comprehensive spectral
analysis, and a concise structural assignment was
unfeasible. The appearance of new signals between 230
and 250 ppm in the course of the decomposition process
suggested that the initially formed complexes decay via
loss of the π-coordinated Cr(CO)3 fragment.
Cr ysta l Str u ctu r e Stu d ies. Crystals of 6‚CH2Cl2,
10a ‚THF, 10b, and 13b‚0.5toluene suitable for single-
crystal X-ray structure determinations were obtained
by crystallization from CH2Cl2/THF and toluene/THF,
respectively. Representations of the molecular struc-
tures of 6, 10a , and 13b are given in Figures 1-3
together with important bond distances and angles. The
molecular structure of 10b differs only insignificantly
from that of 10a and is not shown.
The spectroscopic evidence for the formation of a
π-complex 12 prompted us to investigate if the Ph2P
moiety of 7 might as well be able to bind to a second
transition metal rather than a main group electrophile,
thus giving rise to novel binuclear complexes with a
n(P),π-bridging phosphinylbenzophospholide. To this
end, we reacted 7 with the complexes [M(CO)5(coe)] (M
) Cr, W), which are suitable reagents for the transfer
of 16e-metal fragments, and with silver triflate. The
reactions with the two olefin complexes afforded accord-
ing to 31P NMR studies mixtures of several products.
The main product was in both cases identified as
chromium complex 6, whose formation from 7 and
[W(CO)5(coe)] suggested that a reaction involving in-
termolecular CO scrambling rather than the expected
transfer of an intact M(CO)5 fragment had occurred. In
view of the these unexpected mechanistic complications,
reactions of 7 with metal carbonyls were not pursued
further.
The bonding parameters in the P-coordinated phos-
phoniobenzophospholide moiety in complex 6 differ,
apart from minor shortenings of the exocyclic P(2)-C(2)
(1.786(2) Å) and the endocyclic P(1)-C(9) (1.748(2) Å)
A 31P NMR study of the reaction of 7 with 1 equiv of
silver triflate gave evidence for the formation of rather

5186 Organometallics, Vol. 21, No. 24, 2002
Bajko et al.
F igu r e 1. ORTEP representation of the molecular struc-
ture of 6. Thermal ellipsoids are drawn at the 50%
probability level, and H atoms have been omitted for
clarity. Selected bond lengths (Å): Cr(1)-C(1A) 1.840(3),
Cr(1)-C(1D) 1.892(3), Cr(1)-C(1E), 1.893(3), Cr(1)-C(1B)
1.899(3), Cr(1)-C(1C) 1.906(3), Cr(1)-P(2) 2.4170(7), P(1)-
C(2) 1.734(2), P(1)-C(9) 1.748(2), C(2)-C(3) 1.446(3), C(2)-
P(2) 1.786(2), C(3)-C(4), 1.417(3), C(3)-C(8), 1.421(3),
C(4)-C(5) 1.375(3), C(5)-C(6) 1.401(3), C(6)-C(7) 1.374(3),
C(7)-C(8) 1.418(3), C(8)-C(9) 1.443(3), C(9)-P(3) 1.732(2).
F igu r e 3. ORTEP representation of the molecular struc-
ture of 13b. Thermal ellipsoids are drawn at the 50%
probability level, and H atoms have been omitted for
clarity. Selected bond lengths (Å) and angles (deg): W-C(39)
2.049(4), W-C(40) 1.958(3), W-C(41) 1.972(3), W-C(42)
2.019(4), W-HB1 2.02, (3)W-P(1) 2.4684(7), P(1)-C(4)
1.722(3), P(1)-C(1) 1.738(3), P(2)-C(4) 1.772(3), P(3)-C(1)
1.744(2), P(2)-B 1.943(4), B-HB1 1.15(3), B-HB2 1.15(5),
B-HB3 0.90(3), HB1-W-P(2) 84, B-HB1-W 126.
slightly pyramidal coordination environment of the
coordinated P(1) atom (sum of bond angles 356.0(4)°)
have precedence in other complexes with terminal
benzophospholide ligands.7 The lengthening of the
P(2)-S bond upon coordination (2.0184(12) vs 1.9690(7)
Å in 97) and the Cr-S distance (2.5056(10) Å) represent
typical values for thioxophosphorane metal complexes
(PdS: free 1.945 ( 0.035, coordinated 1.998 ( 0.027,12
Cr-S 2.500 in Cr(CO)5(Me3PS)13). The five-membered
chelate ring adopts a flat twist conformation. The small
bite angle of the bidentate ligand (P(1)-Cr-S 81.36(3)°)
induces a marked distortion of the octahedral coordina-
tion geometry at the chromium atom. Further pla-
narization of the chelate ring might reduce this distor-
tion, but is presumably prevented by steric interference
between the ancillary CO ligands and the bulky Ph3P
group. The Cr-C(41) distance (1.844(4) Å) opposite the
Cr-P(1) bond and the Cr-C(39) (1.899(5) Å) and Cr-
C(42) bonds (1.882(5) Å) in the trans-Cr(CO)2 unit are
similar to the distances of cis- and trans-CO ligands in
6, while the Cr-C(40) bond (1.821(4) Å) is still shorter.
The trend in Cr-C distances points to increasing
π-acceptor power of the trans-ligands in the order
thioxophosphorane < benzophospholide < CO. The
structural parameters of the tungsten complex 10b
displaysapart from a further slight reduction of the
chelate bite angle (P-W-S angle 79.88(6)°), which is
attributable to the larger radius of a tungsten as
compared to a chromium atomsno significant deviations
from those of 10a .
F igu r e 2. ORTEP representation of the molecular struc-
ture of 10a . Thermal ellipsoids are drawn at the 50%
probability level, and H atoms have been omitted for
clarity. Selected bond lengths (Å) and angles (deg): Cr-
C(39) 1.899(5), Cr-C(40) 1.821(4), Cr-C(41) 1.844(4), Cr-
C(42) 1.882(5), Cr-P(1) 2.3262(10), Cr-S 2.5056(10), P(1)-
C(1) 1.714(3), P(1)-C(4) 1.729(3), C(1)-P(2) 1.758(3), C(4)-
P(3) 1.751(3), P(2)-S 2.0184(12), P(1)-Cr-S 81.36(3),
P(2)-S-Cr 108.45(4).
bonds, not significantly from the corresponding values
in the free ligand 5 (P(2)-C(2) 1.8092(13), P(1)-C(9)
1.7623(13) Å9). The distorted octahedral coordination
geometry at the chromium atom with a Cr(1)-P(2)
distance of 2.4170(7) Å and the relative shortening of
the Cr(1)-C(1A) bond (1.840(3) Å) to the trans-CO with
respect to those to the cis-CO ligands (1.892(3)-1.906(3)
Å) are typical features of phosphine-Cr(CO)5 complexes
and require no further comments.
The n(P)-coordination of the benzophospholide moiety
in the chromium complex 10a induces a shortening of
the P(1)-C(1) (1.714(3) Å) and P(1)-C(4) (1.729(3) Å)
bonds and a widening of the C(1)-P(1)-C(4) angle
(94.3(2)°) as compared to the free ligand 9 (1.7353(19)/
1.7540(19) Å/91.50(9)° 9). These effects as well as the
The intraligand distances and angles in the phosphin-
ylbenzophospholide moiety of complex 13b are es-
sentially identical to those in 10a ,b, and the P(2)-B
distance (1.943(4) Å) is indistinguishable within experi-
mental error from that in the free ligand 11 (1.9315(19)
Å9). The P(1) atom adopts a pyramidal coordination
(12) Results of a quest in the CCSD database for phosphine sulfides
X3PdS and their transition metal complexes.
(13) Baker, E. N.; Reay, B. R. J . Chem. Soc., Dalton Trans. 1973,
2205.

Reactions with Electrophiles
Organometallics, Vol. 21, No. 24, 2002 5187
geometry (sum of bond angles 355.3(3)°) similar to that
in 10a ,b. The positions of the BH hydrogen atoms were
located and refined isotropically, and the borane moiety
is despite some irregularities in B-H distances and
P-B-H angles best described as containing two termi-
nal and one bridging B-H bond that is σ-coordinated
to the tungsten atom. The B-H(B1)-W angle of 126°
is close to those in complexes [M(CO)5(η1-H3BPMe3)] (M
) Cr, 130(8)°; M ) W, 128(7)° 11b) and [CpMn(CO)2 (η1-
H3BEMe3)] (E ) N, 142(3)°; E ) P, 129(3)° 11c), and the
W‚‚‚B distance (2.847(4) Å) is comparable to that in
[W(CO)5(η1-H3BPR3)] (R ) Me, Ph, 2.81-2.86 Å11b).
Together, these features suggest descriptions of the
mode of coordination for the borane as end-on and of
the metal-ligand intraction as an “open” three-center
two-electron bond.11b,c Using this notation, the tungsten
atom in 13b is coordinated in a distorted octahedral
geometry defined by the four carbonyls and the P(1) and
the H(B1) atoms of a κ2-P,σ-BH-chelating ligand 11. The
conformation of the formed six-membered chelate ring
is intermediate between twist- and chair-conformations,
and the chelate bite angle (H(B1)-W-P(2) 84°) is
similar to 10a ,b. The trend in W-C distances parallels
that found for 10a ,b, and bond distances increase
depending if the carbonyl is in trans-position to the
hydride (W-C(40) 1.958(3) Å), benzophospholide (W-
C(41) 1.972(3) Å), or a second carbonyl ligand (W-C(39)
2.049(4), W-C(42) 2.019(4) Å).
A Com m en t on Rea ction P a th w a ys. The outcome
of the reactions of the η5-benzophospholide complex 7
with different electrophiles E can be rationalized in
terms of a common pathway via initial quaternization
of the exocyclic Ph2P moiety by the electrophile to afford
a π-complex of a (pseudo)bisphosphonio-substituted
benzophospholide, which then undergoes subsequent
decomposition. The fact that the primary π-complex is
observable by 31P NMR for E ) Ag+, BH3, but not for E
) S, R+, suggests that larger positive charge densities
(i.e., higher phosphonium character) at the phosphorus
atom of the Ph2PE moiety9 have a destabilizing influ-
ence, which is easily rationalized in terms of lower
π-nucleophilicity of the benzophospholide ligand.
The decay of the primary complex occurs in the case
of E ) R+ quantitatively via formation of a bisphospho-
niobenzophospholide cation and loss of the Cr(CO)3
fragment. In the case of E ) S, BH3, which have both
electrophilic and nucleophilic properties, the initial
π-complex decays to give a mixture of the free ligand
and a chelate complex in which the lone pair of the ring
phosphorus atom and either a sulfur lone pair or a BH-
σ-bond occupies two adjacent coordination sites of a Cr-
(CO)4 moiety. Two likely mechanisms may be envisaged
for the formation of this mixture. The first one involves
dissociation of the initial complex to give transient [Cr-
(CO)3(THF)3], subsequent ligand scrambling to yield
[Cr(CO)4(THF)2] besides further unidentified chromium-
containing products, and final recombination of the
benzophospholide and the Cr(CO)4 fragment to a chelate
complex. Alternatively, it can be conceived that the
initial π-complex reacts under take-up of a solvent
molecule (THF) and π/n(P)-coordination isomerization
to a complex in which the ring phosphorus atom and a
sulfur or BH moiety chelates a Cr(CO)3(THF) moiety;
this intermediate then decays in part via cleavage of
the metal fragment to the free phosphorus-containing
ligand and in part via displacement of the coordinated
solvent by another CO (from the liberated Cr(CO)3
moiety) to a tetracarbonyl complex. Even if the observa-
tion of an intermediate of presumed constitution 14 (cf.
Scheme 5) in the reaction of 11 with [Cr(CO)3(napht)]
appears as an argument in favor of an associative
reaction, a dissociative mechanism or a competition
between both pathways may currently not be completely
ruled out.
An interesting aspect of the π/n(P)-coordination isomer-
ization is that, apart from any mechanistic details, the
observed reactivities indicate that η5-coordination of a
benzophospholide moiety with two (quasi)-phosphonio
substituents (-P(+)R3, -R2P(+)-S(-), -R2P(+)-BH3(-)) is
energetically less favorable than a terminal κ2-P,S- or
κ2-P,σ-BH-coordination, respectively. Even though the
capability of phosphine sulfides to form strong dative
bonds to a transition metal is well established, σ-donat-
ing boranates or borane/Lewis-base complexes are nor-
mally considered as much weaker ligands,11 and the
observed trend to trade π(η5)- for σ-BH-coordination may
therefore be considered as remarkable and points to an
unusually weak π-donating power of the zwitterionic or
cationic benzophospholides.
Exp er im en ta l Section
Gen er a l Com m en ts. All manipulations were carried out
under dry argon. Solvents were dried by standard procedures.
NMR spectra: Bruker AMX300 (1H 300.1 MHz, 31P 121.5 MHz,
13C 75.4 MHz, 11B 96.3 MHz, 109Ag 14.0 MHz) in THF-d8 at 30
°C if not stated otherwise; 2D 31P{1H},109Ag HMQC spectra
were recorded using published pulse sequences;14 chemical
shifts referenced to external TMS (1H,13C), 85% H3PO4 (¥ )
40.480747 MHz, 31P), aqueous Ag+ (¥ ) 4.653623 MHz, 109Ag);
BF3‚OEt2 (¥ ) 32.083971 MHz, 11B); positive signs of chemical
shifts denote shifts to lower frequencies, coupling constants
are given as absolute values. Prefixes i-, o-, m-, and p- denote
atoms of phenyl substituents, and atoms in the benzophos-
pholide ring are denoted as 4-C, 5-H, etc.; assignment of
resonances was derived in ambiguous cases from 1H,13C and
1H,31P HMQC NMR spectra. MS: Kratos Concept 1H, Xe-FAB,
m-NBA matrix. Elemental analyses: Heraeus CHNO-Rapid.
The amount of cocrystallized solvents was verified by integra-
tion of suitable 1H NMR signals. Melting points were deter-
mined in sealed capillaries. 31P NMR data are listed in Table
1.
[P en t a ca r b on yl-{3-d ip h en ylp h osp h in yl-1-t r ip h en yl-
p h osp h on ioben zo[c]p h osp h olid e-K1-P }ch r om iu m (0)] (6).
[Cr(CO)5(coe)] (100 mg, 0.33 mmol) and 5 (200 mg, 0.33 mmol)
were dissolved in 10 mL of THF and stirred for 6 h at room
temperature. The red solution was then concentrated in vacuo
to a final volume of 4 mL, and 15 mL of hexane was added.
The precipitated orange solid was collected by filtration,
washed with a little hexane, and dried in high vacuum to give
160 mg (0.21 mmol, 69%) of 6, mp 214 °C. Anal. Calcd for
C
43H29CrO5P3 (770.6)‚hexane: C 68.69; H 5.06. Found: C
69.49; H 5.2. 1H NMR: δ 6.4-6.6 (4H) [4-H to 7-H]; 7.06-
8.12 (25H) [C6H5]. 13C{1H} NMR: δ 97.4 (ddd, J (PAC) ) 57.2
1
Hz, 1J (PXC) ) 99.4 Hz, 3J (PMC) ) 15.5 Hz; C-1), 118.8 (s; C-5),
119.7 (d, J (PXC) ) 1.0 Hz; C-6), 120.7 (d, J (PAC) ) 3.4 Hz;
C-4), 122.8 (dd, 3J (PAC) ) 4.5 Hz, 3J (PXC) ) 4.5 Hz; C-7), 125.1
(dd, 1J (PXC) ) 89.7 Hz, 3J (PAC) ) 2.3 Hz; i-C(PPh3)), 129.6 (d,
4
3
3J (PXC) ) 12.4 Hz; m-C(PPh3)), 128.1 (d, J (PMC) ) 9.2 Hz;
3
(14) Gudat, D. In Annual Reports in NMR Spectroscopy; Webb, G.
A., Ed.; Academic Press: San Diego, 1999; Vol. 38, p 139, and
references therein.

5188 Organometallics, Vol. 21, No. 24, 2002
Bajko et al.
m-C(PPh2)), 129.0 (d, 4J (PMC) ) 2.1 Hz; p-C(PPh2)), 132.4 (dd,
2J (PMC) ) 10.8 Hz, 4J (PAC) ) 1.1 Hz; o-C(PPh2)), 133.6 (d,
4J (PXC) ) 2.9 Hz; p-C(PPh3)), 134.5 (dd, 2J (PXC) ) 10.3 Hz,
with 10 mL of hexane. The formed dark red precipitate was
collected by filtration and dried in a vacuum to give 223 mg
(0.29 mmol, 80%) of 10a , mp 157 °C (dec). Anal. Calcd for
C42H29CrO4P3S (774.7): C 65.12; H 3.77; S 4.14. Found: C 63.7;
H 4.3; S 4.4. 1H NMR: δ 6.51-6.61 (m, 2H; 5-H/6-H), 6.72 (m,
1H; 3-H), 7.06 (m, 1H, 7-H); 7.45 (m, 4H; m-H(PPh2); 7.52 (m,
2H; p-H(PPh2); 7.64 (m, 6H; m-H(PPh3); 7.74 (m, 3H; p-
H(PPh3); 7.83 (m, 4H; o-H(PPh2); 8.01 (m, 6H; o-H(PPh3). 13C-
{1H} NMR: δ 98.4 (dd, 1J (PXC) ) 173 Hz, 1J (PAC) ) 30 Hz;
C-1)); 118.9 (d, J (PC) ) 8.4 Hz; C-6)); 119.2 (dd, J (PC) ) 4.2,
4.3 Hz; C-5)); 119.6 (s; C-4/7); 120.4 (d, J (PC) ) 1.3 Hz; C-4/
7); 125.0 (dd, 1J (PXC) ) 90.4 Hz, 3J (PAC) ) 2.1 Hz; i-C(PPh3));
1
4J (PAC) ) 1.5 Hz; o-C(PPh3)), 137.0 (ddd, J (PAC) ) 51.1 Hz,
1J (PMC) ) 34.4 Hz, 3J (PXC) ) 13.5 Hz; C-3), 138.4 (dd, 1J (PMC)
3
2
) 35.0 Hz, J (PAC) ) 5.6 Hz; i-C(PPh2)), 144.0 (dd, J (PAC) )
4.7 Hz, 2J (PMC) ) 16.5 Hz; C-3a), 145.2 (dd, 2J (PAC) ) 9.3 Hz,
2J (PXC) ) 9.3 Hz; C-7a), 218.0 (dd, 2J (PMC) ) 13.5 Hz, 4J (PAC)
) 4.1 Hz; cis-CO), 232.2 (d, J (PMC) ) 7.6 Hz; trans-CO). MS
2
((+)-Xe-FAB, mNBA): m/e (%) 714 (80) [M+ - 2 CO]; 630 (100)
[M+ - 5 CO]. IR (CH2Cl2, CaF2): νj ) 2058, 1932 cm-1 (νCO).
[Tr ica r b on yl-η5-{3-d ip h en ylp h osp h in yl-1-t r ip h en yl-
p h osp h on ioben zo[c]p h osp h olid e} ch r om iu m (0)] (7). A
mixture of 5 (210 mg, 0.35 mmol) and [Cr(CO)3(napht)] (100
mg, 0.35 mmol) was dissolved in 10 mL of THF and stirred
for 12 h at room temperature. The red solution was then
evaporated in vacuo, and residual naphthalene sublimed off
at 40 °C in high vacuum. The residue was dissolved in 5 mL
of toluene and layered with 15 mL of pentane. A red precipitate
formed, which was filtered off and dried in high vacuum to
give 170 mg (0.24 mmol, 69%) of 6, mp 217 °C. Anal. Calcd
for C41H29CrO3P3 (714.6)‚pentane: C 70.23; H 5.25. Found: C
70.76; H 4.77. 1H NMR: δ 6.73-7.05 (m, 2H), 7.23 (m, 1H),
8.49 (m, 1H) [4-H to 7-H]; 7.07-8.30 (25H) [C6H5]. 13C{1H}
NMR: δ 118.7 (ddd, 1J (PAC) ) 6.7 Hz, 1J (PMC) ) 4.1 Hz,
3J (PXC) ) 2.7 Hz; C-3); 118.8 (dd, 1J (PAC) ) 4.5 Hz, 1J (PXC) )
8.7 Hz; C-1); 121.2 (d, J (PaC) ) 0.8 Hz), 122.7 (s), 122.7 (s),
3
3
129.2 (d, J (PMC) ) 12.6 Hz; m-C(PPh2)); 130.3 (d, J (PXC) )
2
12.6 Hz; m-C(PPh3)); 132.3 (d, J (PMC) ) 2.9 Hz; p-C(PPh2));
2
1
133.2 (d, J (PMC) ) 11.0 Hz; o-C(PPh2)); 133.6 (dd, J (PMC) )
3
4
85.5 Hz, J (PAC) ) 4.7 Hz; i-C(PPh2)); 134.2 (d, J (PXC) ) 3.2
Hz; p-C(PPh3)); 135.1 (d, 2J (PXC) ) 10.3 Hz; o-C(PPh3)); 141.2
(dd, J (PC) ) 15.0, 7.6 Hz; C-7a); 145.2 (dd, 1J (PMC) ) 41.7
Hz, J (PAC) ) 22 Hz; C-3); 147.2 (ddd, J (PC) ) 14.1, 8.9, 2.9
1
2
Hz; C-3a); 218.7 (d, J (PC) ) 17.8 Hz; CO-Cr-CO); 226.8 (d,
2J (PC ) 10.0 Hz; CO); 230.6 (dd, 2J (PC) ) 8.4, 5.2 Hz; CO).
MS ((+)-Xe-FAB, mNBA): m/e (%): 774 (1) [M+], 718 (100)
[M+ - 2 CO], 690 (8) [M+ - 3 CO], 662 (100) [M+ - 4 CO]. IR
(CH2Cl2, CaF2): νj ) 2010, 1905, 1862 cm-1 (νCO).
[Tet r a ca r b on yl-{1-t r ip h en ylp h osp h on io-3-d ip h en yl-
t h i o x o p h o s p h o r a n y lb e n z o [c ]p h o s p h o li d e -K2 -P ,S }-
tu n gsten (0)] (10b). [W(CO)4(nbd)] (198 mg, 0.53 mmol) and
9 (220 mg, 0.35 mmol) were reacted as described above to give
238 mg (0.26 mmol, 75%) of 10b, mp 197 °C (dec). Anal. Calcd
for C42H29WO4P3S (906.5): C 55.65; H 3.22; S 3.54. Found: C
54.4; H 5.0; S 3.1. 1H NMR: δ 6.52-6.64 (m, 2H; 5-H/6-H),
6.71 (m, 1H; 4-H), 7.00 (m, 1H, 7-H); 7.45 (m, 4H; m-H(PPh2);
7.53 (m, 2H; p-H(PPh2); 7.61 (m, 6H; m-H(PPh3); 7.73 (m, 3H;
p-H(PPh3); 7.80 (m, 4H; o-H(PPh2); 7.95 (m, 6H; o-H(PPh3).
1
3
123.0 (s), [C-4 to C-7]; 123.2 (dd, J (PXC) ) 90.0 Hz, J (PAC)
) 1.3 Hz, i-C(PPh3)), 125.2 (m), 127.4 (m) [C-3a/7a)]; 128.0 (s),
125.9 (s) [p-C(PPh2)]; 128.5 (d, J (PMC) ) 11.1 Hz), 127.7 (d,
3
3J (PMC) ) 7.1 Hz [m-C(PPh2)]; 129.7 (d, 3J (PXC) ) 12.4 Hz;
m-C(PPh3)), 134.3 (d, 4J (PXC) ) 2.7 Hz; p-C(PPh3)), 134.5 (dd,
2J (PMC) ) 16.5 Hz, 4J (PAC) ) 1.8 Hz), 133.1 (dd, 2J (PMC) )
19.4 Hz, 4J (PAC) ) 1.0 Hz [o-C(PPh2)]; 134.7 (dd, 2J (PXC) )
9.9 Hz, 2J (PAC) ) 1.7 Hz; o-C(PPh3)), 140.3 (d, 1J (PMC) ) 15.5
1
1
13C{1H} NMR: δ 93.6 (dd, J (PXC) ) 90.0 Hz, J (PAC) ) 32.2
Hz; C-1); 119.3 (m), 119.9 (dd, J (PC) ) 4.0, 5.3 Hz), 120.1 (d,
J (PC) ) 1.6 Hz), 120.8 (s) [C-4 to C-7]; 124.4 (dd, 1J (PXC )
90.5 Hz, 3J (PAC) ) 2.6 Hz; i-C(PPh3)); 129.3 (d, 3J (PMC) ) 12.9
Hz; m-C(PPh2)); 130.4 (d, 3J (PXC) ) 12.6 Hz, m-C(PPh3)); 135.1
Hz, J (PAC) ) 1.5 Hz), 137.3 (d, J (PMC) ) 8.9 Hz, J (PAC) )
8.9 Hz) [i-C(PPh2)]; 236.1 (d, J (PAC) ) 2.9 Hz; CO). MS ((+)-
Xe-FAB, mNBA): m/e (%) 714 (15) [M+], 646 (50) [M+ - C3O2],
630 (100) [M+ - 3 CO]. IR (CH2Cl2, CaF2): νj ) 1927, 1844,
1830 cm-1 (νCO).
1
1
1
2
(d, J (PXC) ) 10.3 Hz; o-C(PPh3)), 132.6 (s, p-C(PPh2)); 132.8
1
3
(dd, J (PMC) ) 85. 2 Hz, J (PAC) ) 4.4 Hz; i-C(PPh2)); 133.2
Rea ction of 7 w ith Electr op h iles (Gen er a l P r oced u r e).
7 (250 mg, 0.35 mmol) was dissolved in 10 mL of THF, and an
equimolar amount of the appropriate electrophile added either
as pure solid (S8, AgOTf) or as solution in THF (MeI, PhCH2-
Br, BH3). After dissolution of all reactants, a portion of the
reaction mixture was transferred to an NMR tube and the
reaction monitored by 31P NMR spectroscopy.
(d, J (PMC) ) 11.3 Hz; o-C(PPh2)); 134.3 (d, J (PXC) ) 3.2 Hz;
2
4
p-C(PPh3)); 145.4 (m; C-3a/7a); 145.7 (m; C-3a/7a); 201.8 (d,
2J (PAC) ) 10.0 Hz; CO-W-CO); 209.6 (d, J (PAC) ) 20.0 Hz;
2
CO); 210.8 (d, 2J (PAC) ) 41.1 Hz; CO). MS ((+)-Xe-FAB,
mNBA): m/e (%) 878 (4) [M+ - CO], 850 (2) [M+ - 2 CO], 794
(12) [M+ - 4 CO]. IR (CH2Cl2, CaF2): νj ) 2014, 1902, 1857
cm-1 (νCO).
1-Me t h yld ip h e n ylp h osp h on io-3-t r ip h e n ylp h osp h o-
n ioben zo[c]p h osp h olid e (8a ). MeI (approximately 100 mg,
0.7 mmol) was added via syringe to a stirred solution of 5 (200
mg, 0.35 mmol) in 5 mL of toluene. The solution was gently
warmed, and stirring was continued until a cream precipitate
separated. The product was collected by filtration, washed with
hexane and ether, and dried in a vacuum to yield 229 mg (32
mmol, 92%) of 8a (mp > 250 °C) as an off-white powder, which
Rea ction of 11 w ith [Cr (CO)4(n bd )]. [Cr(CO)4(nbd)] (90
mg, 0.35 mmol) and 11 (210 mg, 0.35 mmol) were dissolved in
10 mL of THF. After stirring for 4 h, a 31P NMR survey
disclosed the presence of approximately 25% (by integration
of appropriate signals) of 13a (cf. Table 1) besides unreacted
11. Repeated addition of solid [Cr(CO)4(nbd)] increased the
yield of 13a , but led as well to the formation of 6 and small
amounts of further unidentified byproducts. The peak yield
of 13a (approximately 70% of phosphorus-containing species)
was reached after addition of 10.5 equiv of the chromium
complex; a larger excess promoted only further conversion of
13a into 6. Attempts to precipitate complex 13a by addition
of hexane during different stages of the reaction yielded
product mixtures whose further separation remained unfea-
sible.
[Tetr a ca r bon yl-{3-(d ip h en ylp h osp h in ylbor a n e)-1-tr i-
p h e n y lp h o s p h o n i o b e n z o [c ]p h o s p h o li d e -K2 -P ,B H }-
tu n gsten (0)] (13b). [W(CO)4(nbd)] (263 mg, 0.70 mmol) and
11 (210 mg, 0.35 mmol) were dissolved in 10 mL of THF. The
solution was stirred for 24 h at room temperature and layered
with 10 mL of hexane. A brown precipitate formed that was
collected by filtration and dried in a vacuum to give 187 mg
(0.21 mmol, 60%) of 13b, mp 189 °C (dec). Anal. Calcd for
1
was characterized by its H and 31P NMR data. 1H NMR (CD2-
Cl2): δ 2.73 (dd, 2J (PMH ) 12.9 Hz, 4J (PAH) ) 1.8 Hz, 3H,
CH3); 6.90-7.05 (m, 2H) [5-H/6-H]; 7.05 (m, 1H), 7.17 (m, 1H)
[4-H/7-H]; 7.60-7.86 (25H) [C6H5].
1-Be n zyld ip h e n ylp h osp h on io-3-t r ip h e n ylp h osp h o-
n ioben zo[c]p h osp h olid e (8b). Reaction of 5 and PhCH2Br
was conducted as described above, yielding 750 mg (0.31 mmol,
90%) of 8b, mp 172 °C (dec). 1H NMR (CDCl3): δ 4.57 (d,
2J (PMH ) 14.0 Hz, 2H, CH2); 6.70-7.30 (9H; 4-H to 7-H, C6H5-
(benzyl); 7.30-7.80 (25H) [C6H5]. MS ((+)-Xe-FAB, mNBA):
m/e (%) 669 (100) [M+ - Br].
[Tet r a ca r b on yl-{1-t r ip h en ylp h osp h on io-3-d ip h en yl-
th ioxop h osp h or a n ylben zo[c]p h osp h olid e-K2-P ,S}ch r om -
iu m (0)] (10a ). [Cr(CO)4(nbd)] (135 mg, 0.53 mmol) and 9 (220
mg, 0.35 mmol) were dissolved in 10 mL of THF. The resulting
solution was stirred for 24 h at room temperature and layered

Reactions with Electrophiles
Organometallics, Vol. 21, No. 24, 2002 5189
Ta ble 2. Cr ysta llogr a p h ic Da ta a n d Su m m a r y of Da ta Collection a n d Refin em en t for 6, 10a ,b, a n d 13b
6
10a
10b
13b
formula
fw
C
43H29CrO5P3-CH2Cl2
C
46H37CrO5P3S
C42H29O4P3SW
906.47
C44.50H32BO4P3W
918.27
855.50
846.73
cryst size
cryst syst, space group
unit cell dimens
0.35 × 0.15 × 0.02 mm
triclinic, P1h (No. 2)
a ) 9.5017(2) Å
b ) 12.4747(2) Å
c ) 18.3005(4) Å
R ) 76.515(1)°
â ) 80.180(1)°
γ ) 74.624(1)°
2020.15(7) Å3
2, 1.42 Mg/m3
0.58 mm-1
0.18 × 0.05 × 0.02 mm
monoclinic, P21/c
a ) 10.9086(2) Å
b ) 22.0459(5) Å
c ) 17.3373(3) Å
0.30 × 0.10 × 0.05 mm
monoclinic, Cc (No. 9)
a ) 17.8938(5) Å
b ) 13.2188(3) Å
c ) 16.4646(4) Å
0.34 × 0.16 × 0.1 mm
monoclinic, P21/c
a ) 11.06270(10) Å
b ) 21.8693(2) Å
c ) 17.3806(2) Å
â ) 101.930(2)°
â ) 106.520(1)°
â ) 102.36°
volume
4079.39(14) Å3
4, 1.38 Mg/m3
0.50 mm-1
1752
3733.69(16) Å3
4, 1.61 Mg/m3
3.32 mm-1
1792
4107.41(7) Å3
4, 1.49 Mg/m3
2.86 mm-1
1820
Z, Fcalc
µ
F(000)
876
θ range for data
collection
2.95 to 25.32°
3.67 to 25.03°
2.58 to 25.00°
3.04 to 27.43°
completeness of data
max. and min. transmn
limiting indices
96.8%
1.035 and 0.973
-12 e h e 12,
-26 e k e 26,
-20 e l e 19
41 298/7154
0.5444 and 0.4481
-21 e h e 21,
-15 e k e 15,
-19 e l e 19
38 503/6561
[Rint ) 0.0878]
empirical from
multiple reflns
6561/2/461
1.073 and 0.948
-14 e h e 14,
-28 e k e 28,
-22 e l e 22
74 507/9350
-11 e h e 11,
-14 e k e 15,
-21 e l e 22
27 049/7152
[Rint ) 0.0372]
none
reflections collected/
unique
abs corr
[Rint ) 0.0770]
multiscan
[Rint ) 0.0541]
multiscan
no. of data/restraints/
params
7152/0/496
7148/0/592
9350/0/504
goodness-of-fit on F2
R1 [I > 2σ(I)]
1.065
0.037
0.010
1.080
0.048
0.117
0.997
0.034
0.073
1.081
0.027
0.069
wR2 (all data)
largest diff. peak and hole
0.352 and -0.391 e Å-3
0.574 and -0.418 e Å-3
0.662 and -1.424 e Å-3
0.833 and -1.153 e Å-3
C
42H32BO4P3W (888.3): C 56.79; H 3.63. Found: C 56.8; H 3.9.
data collection parameters, and results of the analyses are
listed in Table 2. The structures were solved by direct methods
(SHELXS-9715a) and refined anisotropically by blocked cycle
1H NMR: δ -1.33 (br, 3H; BH3); 6.45 (m, 1H; 4-H/7-H); 6.52
(m, 1H; 5-H/6-H); 6.65 (m, 1H; 5-H/6-H), 7.06 (m, 1H, 4-H/7-
H); 7.43 (m, 6H; m-H(PPh3); 7.57-7.76 (m, 13H; C6H5); 8.00
(m, 6H; o-H(PPh3). 11B NMR: δ -40.3 (br). 13C{1H} NMR: δ
118.0 (dd, J (PC) ) 6.5, 3.6 Hz; C-6); 118.7 (ddd, J (PC) ) 11.0,
1.5, 1.4 Hz; C-5/6); 119.0 (d, J (PC) ) 2.3 Hz; C-4/7); 119.1 (s;
C-4/7); 123.7 (dd, 1J (PXC) ) 90.5 Hz, 3J (PAC) ) 2.3 Hz;
i-C(PPh3)); 128.2 (d, 3J (PMC) ) 10.6 Hz; m-C(PPh2)); 128.8 (dd,
1J (PMC) ) 64.1 Hz, 3J (PAC) ) 7.6 Hz; i-C(PPh2)); 129.0 (d,
3J (PXC) ) 12.9 Hz; m-C(PPh3)); 130.4 (d, 2J (PMC) ) 2.9 Hz;
full-matrix least-squares on F2 using all data (SHELXL-9715b
)
using an empirical absorption correction from multiple reflec-
tions (10b), or multiscan absorption corrections (6, 10a , 13b).
The BH atoms in 13b were located and refined isotropically;
all remaining H atoms were refined with a riding model. The
crystal of 10b was a racemic twin and gave an absolute
structure parameter of 0.362(7). The solvent molecule (toluene)
in the structure of 13b‚0.5toluene was disordered.
p-C(PPh2)); 132.3 (d, J (PMC) ) 9.7 Hz; o-C(PPh2)); 133.0 (d,
2
4J (PXC) ) 3.0 Hz; p-C(PPh3)); 134.0 (d, 2J (PXC) ) 10.3 Hz;
o-C(PPh3)); 141.9 (dd, J (PC) ) 15.2, 2.9 Hz; C-3a/7a); 144.7
(dd, J (PC) ) 14.5, 5.9 Hz; C-3a/7a); 200.5 (d, 2J (PC) ) 10.3
Hz; CO-Cr-CO); 204.7 (d, 2J (PC ) 5.2 Hz; CO); 206.8 (d,
2J (PC) ) 36.3 Hz; CO). 183W NMR: δ -2858. MS ((+)-Xe-FAB,
mNBA): m/e (%) 860 (16) [M+ - CO], 846 (9) [M+ - CO, -
BH3], 818 (4) [M+ - 2 CO, - BH3]. IR (CH2Cl2, CaF2): νj )
2380, 2340 (sh) cm-1, (νBH); 1980, 1925, 1867 cm-1 (νCO).
Cr ysta llogr a p h y. Crystals of composition 6‚CH2Cl2, 10a ‚
THF, 10b , and 13b ‚0.5toluene were obtained from CH2Cl2/
THF and toluene/THF, respectively. The crystal structure
Ack n ow led gm en t . We thank the Deutsche For-
schungsgemeinschaft for financial support.
Su p p or tin g In for m a tion Ava ila ble: Expansion of the 1H
NMR spectrum of 13b under different decoupling conditions;
tables of atom parameters, anisotropic temperature factors,
and bond distances and angles for 6‚CH2Cl2, 10a ‚THF, 10b,
and 13b‚0.5toluene. This material is available free of charge
via the Internet at http://pubs.acs.org.
OM020404V
determinations were performed on
a Nonius KappaCCD
diffractometer at 123(2) K (for 6, 10b) or 223(2) K (for 10a ,
13b) using Mo KR radiation (λ ) 0.71073 Å). Crystal data,
(15) (a) Sheldrick, G. M. Acta Crystallogr. 1990, A46, 467. (b)
Sheldrick, G. M. SHELXL-97; University of Go¨ttingen, 1997.