First examples of spirooxaphosphirane complexes

Article abstract of DOI:10.1021/om200431f

The reaction of a transient Li/Cl phosphinidenoid pentacarbonyltungsten complex (R = CH(SiMe₃)₂) with cyclohexanone, cyclopentanone, and cyclobutanone yielded the novel, atropisomeric spirooxaphosphirane complexes 3a,b-5a,b, while 2,3-diphenylcyclopropenone furnished selectively the 1,2-dihydrophosphet- 2-one complex 6. All complexes have been characterized by heteronuclear NMR, mass spectrometry, and singlecrystal X-ray analysis in the case of 4a, 5a, and 6.

Full text of DOI:10.1021/om200431f

ARTICLE
pubs.acs.org/Organometallics
First Examples of Spirooxaphosphirane Complexes
Janaina Marinas Pꢀerez, Melina Klein, Andreas Wolfgang Kyri, Gregor Schnakenburg, and Rainer Streubel*
Institut f€ur Anorganische Chemie, Rheinische Friedrich-Wilhelms-Universit€at Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
S Supporting Information
b
ABSTRACT: The reaction of a transient Li/Cl phosphinidenoid
pentacarbonyltungsten complex (R = CH(SiMe3)2) with cyclo-
hexanone, cyclopentanone, and cyclobutanone yielded the novel,
atropisomeric spirooxaphosphirane complexes 3a,bÀ5a,b, while
2,3-diphenylcyclopropenone furnished selectively the 1,2-dihy-
drophosphet-2-one complex 6. All complexes have been char-
acterized by heteronuclear NMR, mass spectrometry, and single-
crystal X-ray analysis in the case of 4a, 5a, and 6.
piroalkanes such as spiropentanes (I) have been intensi-
Scheme 1. Spiropentane (I), Phospha-Spiropentane Deriva-
S
vely studied by experimentalists as well as theoreticians.1
tives IIÀIV, and Phospha-Spiroheterocycles Va
Although spiroheterocycles are present in a large number of
natural products2 and show physical properties of particular
interest,3 the area of phosphorus-containing spiroheterocycles is
deeply underdeveloped and, moreover, the research has been
focused on phosphorusÀcarbon ring systems4 such as the phos-
pha-spiropentanes IIÀIV (Scheme 1). Whereas most derivatives
of II5,6 and III7 were bound to a transition-metal center,8 the only
known derivative of IV9 (all tert-butyl substituted) was obtained
nonligated. To the best of our knowledge, nothing is known about
spiroheterocycles that have another heteratom (as in V) and,
therefore, the question of the effect of a (very) polar ring bond on
structure and reactivity has not been addressed before.
Theoretical investigations on monocyclic oxaphosphirane
derivatives revealed a considerable ring strain of 23.2 kcal/mol
for the parent system (RI-CCSD(T)/TZVPP), while for tri-
methyloxaphosphirane pentacarbonylchromium(0) a slightly smal-
ler mean value of 22.0 kcal/mol was obtained (RI-SCS-MP2/
TZVPP);10 this transition-metal effect was not studied further.
Recent experimental studies on acid-induced ring opening11 of
monocyclic oxaphosphirane complexes have demonstrated that
they have become valuable new building blocks which deserve
further study. On the basis of the convenient methodology for
oxaphosphirane complexes that was developed recently,12 we felt
attracted by the idea to establish a method that enables access to
spiroheterocycles of type V as new ligand systems, which have
various ring sizes and various heteroatoms E.
a R denotes organic substituents, the dashed line in V indicates various
ring sizes, and E indicates a heteroatom other than phosphorus.
reacted in situ with cyclohexanone, cyclopentanone, and cyclo-
butanone, thus yielding the spirooxaphosphirane complexes
3a,bÀ5a,b (Scheme 2).
In all reactions the two isomers a and b were formed (3a,b,
23:77; 4a,b, 55:45; 5a,b, 69:31; determined via integration of the
31P{1H} NMR spectra); only in the case of complexes 3a,b was
the major isomer the b isomer, while in all other cases (4a,b and
5a,b) was the minor isomer. Column chromatography yielded
only isomer 3b in pure form (see below), while the other
complexes could not be separated and thus were purified and
characterized as mixtures. Despite this, the structures of com-
plexes 4a and 5a were unambiguously confirmed by single-crystal
X-ray analysis; for selected data see Figures 1 and 2.
Here, we report the facile synthesis of the first spirooxapho-
sphirane complexes (E = O) using the Li/Cl phosphinidenoid
complex route and cyclic ketones. Furthermore, a first attempt to
access a phospha-spiropentene complex derivative using this
particular route is described.
’ RESULTS AND DISCUSSION
Chlorine/lithium exchange in complex 1,13 using tert-butyl-
lithium in the presence of 12-crown-4 at low temperature, led to
the transient Li/Cl phosphinidenoid complex 2,12a which was
Received: May 23, 2011
Published: October 11, 2011
r
2011 American Chemical Society
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dx.doi.org/10.1021/om200431f Organometallics 2011, 30, 5636–5640
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Scheme 2. Synthesis of the Spirooxaphosphirane Complexes
3a,bÀ5a,b and Surprising Formation of the 1,2-Dihydro-
phosphet-2-one Complex 6
Figure 2. Molecular structure of complex 5a (two independent mol-
ecules in the crystal; 50% probability level; hydrogen atoms are omitted
for clarity; because of great similarity only one data set is given). Selected
bond lengths (Å) and angles (deg): W1ÀP1 = 2.4526(7), P2ÀW2 =
2.4743(7), C1ÀO1 = 1.477(3), C17ÀO7 = 1.469(3), C1ÀP1 =
1.779(3), C17ÀP2 = 1.776(3), C5ÀP1 = 1.796(3), C21ÀP2 =
1.807(3), O1ÀP1 = 1.674(2), O7ÀP2 = 1.6714(19); O1ÀP1ÀC1 =
50.53(11), O7ÀP2ÀC17 = 50.32(11), C1ÀO1ÀP1 = 68.42(14),
C17ÀO7ÀP2 = 68.52(13).
complexes)12b,c and one in which it points in the opposite direction
(“s-trans”, as in azaphosphiridine complexes).15 Therefore,
we carried out a temperature-dependent 31P{1H}NMR spectro-
scopic study using complexes 3a,b as a good case in point.
Heating a toluene solution of a mixture (23:77, 25 °C) to 90 °C
led to a ratio of 86:14, which did not change upon prolonged
heating or subsequent cooling to 25 °C; coalescence was not
observed. The 1H NMR spectrum of 3a, with a slight impurity of
2
3b (∼7%), revealed a significantly smaller J(P,H) coupling
constant value for the exo CH proton (as compared to 3b),
and thus this is in line with an “s-cis” conformation at the exo
PÀC bond. It thus became apparent that there is a very good
correlation between the size of this coupling constant value and
the relative orientation of the CH(SiMe3)2 group: i.e., “s-cis” is
the preferred conformation for oxaphosphirane derivatives with
C-substituents of low or lower steric demand (such as complexes
4a and 5a, here) or other C-monosubstituted derivatives re-
ported earlier. Therefore, it is in perfect agreement that the
isomer ratios change if the steric demand changes.
Figure 1. Molecular structure of complex 4a in the crystal (50%
probability level; 67% main orientation of the cyclopentane ring unit
(solid line) and 33% (dashed line); only the crystallographic data of
the main structure are given, as the second disordered structure is mainly
the same; hydrogen atoms are omitted for clarity). Selected bond lengths
(Å) and angles (deg): WÀP = 2.4781(10), PÀO1 = 1.666(3), C1À
O1 = 1.492(5), PÀC1 = 1.795(4); PÀO1ÀC1 = 69.00(18),
C1ÀPÀO1 = 50.92(16), O1ÀC1ÀP = 60.08(17).
When the transient complex 2 was reacted with 2,3-diphe-
nylcyclopropenone, the selective formation of the 1,2-dihydro-
phosphet-2-one complex 6 was observed (Scheme 2), but no
evidence for the targeted unsaturated spirooxaphosphirane com-
plex was obtained. Nevertheless, this points to a oxaspiropenteneÀ
cyclobutenone rearrangement of an intermediate complex,
which would be closely related to what was proposed by Mathey
and Bertrand.16 In addition, the reaction pathway may include
an acyclic intermediate in which the CH(SiMe3)2 group can freely
rotate and thus find the thermodynamic sink. Complex 6,
obtained in pure form after column chromatography, showed
In general, complexes 3a,bÀ5a,b showed phosphorus reso-
nances between 31 and 58 ppm, in accordance with the values of
monocyclic oxaphosphirane complexes.12b,c Within this series of
spirooxaphosphirane complexes the trend became apparent that
with decreasing ring size of the all-carbon ring unit the phos-
phorus resonance was shifted to higher field (Table 1).
Complexes 3a,bÀ5a,b all showed similar 1J(W,P) values
(292.5À296.3 Hz), although the values for the b isomers were
most often slightly smaller. As the origination of the two isomers
(of 3À5) was not apparent, we had the idea to test if atropi-
somerism might be responsible: i.e., a hindered rotation around
the exo PÀC bond.14 Furthermore, we knew from crystal struc-
tures of azaphosphiridine complexes14 bearing this substituent
(R1 = CH(SiMe3)2) that this group can adopt two orientations
if sterically required: one with the CH group pointing toward
the W(CO)5 group (“s-cis”, as in monocyclic oxaphosphirane
1
a phosphorus resonance at 91.5 ppm with a J(W,P) value of
230.2 Hz.
Single-crystal X-ray diffraction analyses of complexes 4a and
5a (Figures 1 and 2) showed the presence of the R and S enan-
tiomers in the unit cells. The structure of complex 4a was
disordered in the cyclopentane unit (67:33). A general structural
feature of both spiro compounds is the almost perpendicular
arrangement of the oxaphosphirane ring plane and the planes
defined by the spiro atom and its next neighboring carbon atoms
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Table 1. 31P, 1H, and 13C NMR Data (CDCl3) of Complexes 3a,bÀ5a,b
that the product ratio strictly depended on the steric demand of
the all-carbon ring unit. Heating a solution of a mixture of 3a,b
was used to bring about a change in the ratio of the two confor-
mers. This also unveiled an interesting stereochemical feature of
the CH(SiMe3)2 group, as it is able to behave in a binary manner.
If 2,3-diphenylcyclopropenone was reacted with complex 1,
the targeted product, a spirooxaphosphetene complex, was not
observed, but the 1,2-dihydrophosphet-2-one complex 6 was
obtained selectively, thus pointing to some kind of rearrange-
ment reaction. Current studies aim at ring-opening reactions of
spirooxaphosphirane complexes.
’ EXPERIMENTAL SECTION
Figure 3. Molecular structure of complex 6 (50% probability level;
hydrogen atoms are omitted for clarity). Selected bond lengths (Å) and
angles (deg): WÀP = 2.5140(12), C3ÀP = 1.860(5), C2ÀC3 =
1.369(6), C2ÀC1 = 1.488(7), C1ÀP = 1.902(5), C4ÀP = 1.818(5),
C1ÀO1 = 1.205(6); C3ÀPÀC1 = 70.9(2), C2ÀC1ÀP = 91.7(3),
C3ÀC2ÀC1 = 99.5(4).
All reactions were carried out under an inert gas atmosphere using
purified and dried argon and standard Schlenk techniques. Solvents were
dried over sodium wire and distilled under argon. NMR data were
recorded on a Bruker DMX 300 spectrometer at 25 °C using CDCl3 as
solvent and internal standard; chemical shifts are given in ppm relative to
tetramethylsilane (1H, 300.13 MHz; 13C, 75.5 MHz; 29Si, 59.6 MHz),
and 85% H3PO4 (31P, 121.5 MHz). Mass spectra were recorded on a
MAT 95 XL Finnigan (EI, 70 eV, 184W) spectrometer; selected data are
given. Elemental analyses were performed by using an Elementar
VarioEL instrument.
Complexes 3a,bÀ5a,b. To a freshly prepared solution of complex
2 (261 mg, 0.47 mmol) in Et2O (6 mL) was added 3 equiv of the ketone
(0.15 mL of cyclohexanone, 0.11 mL of cyclobutanone, 0.13 mL of
cyclopentanone), and the reaction mixture was warmed to 0 °C. The
solvents were removed in vacuo (∼10À2 mbar) and the products
extracted with a 1:1 mixture of Et2O and n-pentane and purified by
column chromatography (Al2O3, À30 °C, petroleum ether). The first
fraction yielded pure 3b, while the second fraction yielded a mixture of
both isomers 3a,b (or 4a,b or 5a,b) as a yellow oil. Complexes 4a,b
(yield 155 mg (0.26 mmol, 55%)) and 5a,b (yield 107 mg (0.19 mmol,
39%)) were isolated as mixtures only. When a toluene solution of
complexes 3a,b (c = 0.16 mol/L) was heated for 2 h at 90 °C, the ratio
changed from 23:77 (25 °C) to 86:14. The product was purified by
column chromatography (Al2O3, À20 °C, petroleum ether). During
chromatography the percentage of diethyl ether was increased. The first
fraction (1% Et2O) yielded 3b and 3a in a ratio of 93:7. The second
fraction (5À10% Et2O) yielded 3b and 3a in a ratio of 37:63.
of the cyclopentane (4a) and cyclobutane ring (5a) (89.16 and
86.98°). In the case of complex 4a an envelope and in 5a a
butterfly conformation was found. All complexes show an acute
endocyclic angle at the phosphorus center (48À51°). Both com-
plexes 4a and 5a display an “s-cis” conformation of the CH
proton of the CH(SiMe3)2 group and the W(CO)5 group at the
PÀC bond.
The structure of complex 6 (Figure 3) confirmed that the
phosphorus is part of a four-membered-ring system which is
characterized by the C2ÀC3 distance (1.369(6) Å) and an acute
angle at phosphorus (C1ÀPÀC3 = 70.9°).
’ CONCLUSIONS
The reaction of transient Li/Cl phosphinidenoid complex 1
with cyclic ketones has enabled the synthesis of novel spiroox-
aphosphirane complexes that were obtained as mixtures of exo-
PÀC atropisomers. A detailed 31P{1H} NMR spectroscopic
study, using complexes 3a,b as a good case in point, revealed
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3a: yield of the mixture 168 mg (0.30 mmol, 58%) (analytical data
obtained from a 93:7 mixture of 3a and 3b); 13C{1H} NMR δ 1.9
(d, 3J(P,C) = 4.3 Hz, Si(CH3)3), 2.3 (d, 3J(P,C) = 7.9 Hz, Si(CH3)3),
23.7 (d, 2,3,4J(P,C) = 7.9 Hz, CH2), 24.7 (d, 2,3,4J(P,C) = 2.8 Hz, CH2), 25.3
(s, CH2), 31.9 (s, CH2), 32.3 (d, 1J(P,C) = 17.7 Hz, CH(Si(CH3)3)2,),
34.4 (d, 2,3,4J(P,C) = 7.2 Hz, CH2), 67.3 (d, 1J(P,C) = 29.5 Hz, PCO),
196.1 (d, 2J(P,C) = 8.3 Hz, cis-CO), 196.2 (d, 2J(P,C) = 32.8 Hz, trans-
CO); 31P{1H} NMR δ 57.7 (ssat, 1J(P,W) = 296.2 Hz); 1H NMR δ 0.26
(s, 9H, Si(CH3)3), 0.28 (s, 9H, Si(CH3)3), 1.29 (d, 1H, 2J(P,H) = 2.9
Hz, CH(Si(CH3)3)2), 1.58À1.87 (m, 8H, CH2), 1.87À1.98 (m, 2H,
CH2); 29Si{1H} NMR δ À1.3 (d, 2J(P,Si) = 6.5 Hz, Si(CH3)3), 0.9 (d,
2J(P,Si) = 8.3 Hz, Si(CH3)3).
5b (analytical data obtained from the mixture but assigned on the
basis of the previous case study of 3a,b): 13C{1H} NMR δ 1.9 (d, 2J(P,
2
C) = 0.7 Hz, Si(CH3)3), 1.9 (d, J(P,C) = 2.3 Hz, Si(CH3)3), 13.4
1
(d, 2,3J(P,C) = 3.8 Hz, CH2), 28.7 (d, J(P,C) = 37.9 Hz, CH), 30.8
(s, CH2), 32.5 (d, 2,3J(P,C) = 2.8 Hz, CH2), 70.2 (d, 1J(P,C) = 23.1 Hz,
ipso-C), 195.4 (d, 2J(P,C) = 8.2 Hz, cis-CO), 196.5 (d, 2J(P,C) = 31.9 Hz,
trans-CO); 31P{1H} NMR δ 31.4 (ssat, 1J(P,W) = 292.5 Hz); 1H NMR δ
0.30 (s, 9H, Si(CH3)3), 0.31 (s, 9H, Si(CH3)3), 0.72 (d, 1H, 2J(P,H) =
17.4 Hz, CH), 1.83À2.07 (m, 2H, CH2), 2.36À2.52 (m, 2H, CH2),
2.59À2.70 (m, 2H, CH2); 29Si{1H} NMR δ À0.8 (d, 2J(P,Si) = 5.7 Hz,
SiMe3), 3.6 (d, 2J(P,Si) = 1.6 Hz, SiMe3); MS m/z (EI) 584 (20) [M]•+,
556 (5) [M À CO]•+, 528 (15) [M À 2CO]•+, 514 (30) [M À
C4H6O]•+, 486 (100) [M À CO À C4H6O]•+, 458 (25) [M À 2CO À
C4H6O]•+, 73 (90) [Si(CH3)3]•+. Anal. Calcd for C16H25O6PSi2W
(584.04 g/mol): C, 32.89; H, 4.31. Found: C, 32.95; H, 4.32.
3b: yield 30 mg (0.05 mmol, 10%); 13C{1H} NMR δ 2.0 (d,
3
3J(P,C) = 4.9 Hz, Si(CH3)3), 2.1 (d, J(P,C) = 2.9 Hz, Si(CH3)3),
24.2 (d, 2,3,4J(P,C) = 5.5 Hz, CH2), 25.1 (d, 2,3,4J(P,C) = 2.2 Hz, CH2),
25.6 (d, 1J(P,C) = 38.8 Hz, CH(Si(CH3)3)2,), 25.7 (s, CH2), 31.1
(s, CH2), 34.9 (d, J(P,C) = 6.7 Hz, CH2), 67.9 (d, 1J(P,C) = 27.3 Hz,
PCO), 196.1 (d, 2J(P,C) = 8.2 Hz, cis-CO), 196.8 (d, 2J(P,C) = 32.0 Hz,
trans-CO); 31P NMR δ 47.1 (dqsat, 1J(P,W) = 295.6 Hz, 2J(P,H) = 14.8
Hz, 2J(P,H) = 12.6 Hz); 1H NMR δ 0.29 (s, 9H, Si(CH3)3), 0.34 (s, 9H,
Si(CH3)3), 1.26 (d, 1H, 2J(P,H) = 15.9 Hz, CH(Si(CH3)3)2),
1.55À1.69 (m, 2H, CH2), 1.69À1.86 (m, 5H, CH2), 1.86À2.02 (m,
3H, CH2); 29Si{1H} NMR δ À1.5 (d, 2J(P,Si) = 5.8 Hz, Si(CH3)3), 4.0
(s, Si(CH3)3); MS m/z (EI) 612 (30) [M]•+, 584 (20) [M À CO]•+, 556
(15) [M À 2CO]•+, 514 (40) [M À C6H10O] •+, 486 (15) [M À CO À
C6H10O]•+, 73 (100) [Si(CH3)3]•+. Anal. Calcd for C18H29O6PSi2W
(612.07 g/mol): C, 35.40; H, 4.77. Found: C, 35.15; H, 4.70.
Complex 6. To a freshly prepared solution of complex 2 (310 mg,
0.52 mmol) in Et2O (9 mL) was added 130 mg (0.63 mmol) of 2,
3-diphenylcyclopropenone, and the reaction mixture was warmed to
ambient temperature. The solvent was removed in vacuo (∼10À2
mbar), and the product was extracted with 3 Â 6 mL of n-pentane
and purified by column chromatography (SiO2, À20 °C, petroleum
ether/diethyl ether 9/1).
Complex 6 was isolated as an orange solid: yield 237.9 mg (0.33
mmol, 63%); 13C{1H} NMR δ 2.4 (d, 3J(P,C) = 2.6 Hz, Si(CH3)3), 2.6
3
1
(d, J(P,C) = 2.6 Hz, Si(CH3)3), 26.4 (d, J(P,C) = 25.9 Hz, CH-
(SiMe3)2), 128.7 (s, Ph), 128.8 (s, Ph), 128.8 (s, Ph), 129.0 (s, Ph),
129.9 (s, Ph), 131.1 (s, Ph), 133.1 (s, Ph), 133.2 (s, Ph), 148.4 (d, 2J(P,
C) = 53.7 Hz, PhCC(O)), 174.9 (d, 1,3J(P,C) = 25.9 Hz, PhCP), 195.3
(d, 2J(P,C) = 31.0 Hz, C(O)), 196.8 (d, 2J(P,C) = 5.8 Hz, cis-CO), 198.9
4a (analytical data obtained from the mixture but assigned on the
basis of the previous case study of 3a,b): 13C{1H} NMR δ 2.0 (d, 3J(P,
3
2
(d, J(P,C) = 23.9 Hz, trans-CO); 31P{1H} NMR δ 91.5 (1J(P,W) =
C) = 4.4 Hz, Si(CH3)3), 2.3 (d, J(P,C) = 2.6 Hz, Si(CH3)3), 25.9
(d, 2,3J(P,C) = 3.7 Hz, CH2), 29.7 (d, 1J(P,C) = 8.7 Hz, CH), 33.1 (d,
230.2 Hz); 1H NMR δ À0.02 (s, 9H, Si(CH3)3), 0.30 (s, 9H, Si(CH3)3),
2
2,3J(P,C) = 1.3 Hz, CH2), 35.2 (d, J(P,C) = 7.9 Hz, CH2), 39.9 (s,
2
1.38 (d, J(P,H) = 10.0 Hz, 1H, CH(Si(CH3)3)2), 7.24 (m, 3H, Ph),
CH2), 73.4 (d, 1J(P,C) = 31.4 Hz, ipso-C), 195.9 (d, 2J(P,C) = 8.4 Hz,
cis-CO), 198.1 (d, 2J(P,C) = 32.5 Hz, trans-CO); 31P{1H} NMR δ 48.4
(ssat, 1J(P,W) = 296.3 Hz); 1H NMR δ 0.19 (s, 9H, Si(CH3)3), 0.22 (s,
7.39 (m, 5H, Ph), 7.64 (m, 2H, Ph); 29Si{1H} NMR δ 0.56 (d, 2J(P,Si) =
7.6 Hz, SiMe3); 1.48 (d, 2J(P,Si) = 4.7 Hz, SiMe3); MS m/z (EI) 720
(70) [M]•+, 664 (11) [M À 2CO]•+, 647 (14) [M À SiMe3]•+, 636 (20)
[M À 3CO]•+, 608 (100) [M À 4CO]•+, 580 (25) [M À 5CO]•+, 552
(50) [M À 6CO]•+, 536 (30) [M À 4CO À SiMe3 + H+]•+, 506 (39)
[M À 5CO À SiMe3 À H]•+, 486 (70) [M À CO À C(Ph)C(Ph)-
(CO)]•+, 478 (40) [M À 6CO À SiMe3 À H]•+, 458 (20) [M À 2CO À
C(Ph)C(Ph)(CO)]•+, 434 (18) [M À 5CO À 2SiMe3]•+, 178 (20)
[(Ph)CdC(Ph)]•+, 73 (100) [SiMe3]•+. Anal. Calcd for C27H29O6P-
Si2W (720.5 g/mol): C, 45.01; H, 4.06. Found: C, 44.00; H, 4.77.
Crystal Data for 4a. Suitable single crystals of 4a were obtained
from a concentrated n-pentane solution on cooling to À20 °C. Data
were collected with a Nonius KappaCCD diffractometer equipped with
a low-temperature device at 100 K by using graphite-monochromated
Mo Kα radiation (λ = 0.710 73 Å). The structure was solved by
Patterson methods (SHELXS-97)17a and refined by full-matrix least
squares on F2 (SHELXL-97):17b C17H27O6PSi2W, Mr = 598, colorless,
crystal dimensions 0.600 Â 0.220 Â 0.200 mm3, monoclinic, space
group P21/c, Z = 4, a = 9.2863(4) Å, b = 11.6174(4) Å, c = 21.6493(6) Å,
β = 95.300(2)°, V = 2325.60(14) Å3, Dexptl = 1.709 g cmÀ3, μ =
5.166 mmÀ1, T = 123(2) K, transmission factors (min/max) 0.214
25/0.331 16, analytical absorption correction based on the indexing of
the crystal faces,15 2θmax= 54.0°, 4952 unique data, Rint = 0.0510, R1 (for
I > 2σ(I)) = 0.0282, wR2 (for all data) = 0.0624, final R = 0.0282,
2
9H, Si(CH3)3), 1.30 (d, 1H, J(P,H) = 4.2 Hz), 1.66À1.79 (m, 4H,
CH2), 2.00À2.29 (m, 4H, CH2); 29Si{1H} NMR δ À1.3 (d, 2J(P,Si) =
6.4 Hz, SiMe3), 1.3 (d, 2J(P,Si) = 6.4 Hz, SiMe3).
4b (analytical data obtained from the mixture but assigned on the
basis of the previous case study of 3a,b): 13C{1H} NMR δ 2.0 (d, 3J(P,
3
C) = 3.6 Hz, Si(CH3)3), 2.0 (d, J(P,C) = 4.6 Hz, Si(CH3)3), 25.6
1
(d, 2,3J(P,C) = 4.2 Hz, CH2), 28.8 (d, J(P,C) = 37.7 Hz, CH), 33.2
2
(d, 2,3J(P,C) = 2.0 Hz, CH2), 34.7 (d, J(P,C) = 6.9 Hz, CH2), 38.5
(s, CH2), 74.7 (d, 1J(P,C) = 31.0 Hz, ipso-C), 196.9 (d, 2J(P,C) = 8.4 Hz,
cis-CO), 196.5 (d, 2J(P,C) = 31.6 Hz, trans-CO); 31P{1H} NMR δ 36.2
(1J(P,W) = 293.7 Hz); 1H NMR δ 0.22 (s, 9H, Si(CH3)3), 0.26 (s, 9H,
Si(CH3)3), 1.02 (d, 1H, 2J(P,H) = 16.8 Hz), 1.73À1.84 (m, 2H, CH2),
1.90À1.98 (m, 2H, CH2), 2.12À2.28 (m, 4H, CH2); 29Si{1H} NMR δ
À1.2 (d, 2J(P,Si) = 5.6 Hz, SiMe3), 3.4 (d, 2J(P,Si) = 1.0 Hz, SiMe3); MS
m/z (EI) 598 (5) [M]•+, 570 (10) [M À CO]•+, 542 (10) [M À
2CO]•+, 514.0 (40) [M À C6H10O]•+, 486.0 (100) [M À CO À
C6H10O]•+, 73 (95) [Si(CH3)3]•+. Anal. Calcd for C17H27O6PSi2W
(598.06 g/mol): C, 34.12; H, 4.55. Found: C, 34.15; H, 4.52.
5a (analytical data obtained from the mixture but assigned on the
basis of the previous case study of 3a,b): 13C{1H} NMR δ 2.0 (d, 2J(P,
2
C) = 2.7 Hz, Si(CH3)3), 2.1 (d, J(P,C) = 4.4 Hz, Si(CH3)3), 13.7
goodness of fit 0.979, ΔF(max/min) = 1.259/À1.306 e ÅÀ3
.
1
(d, 2,3J(P,C) = 3.8 Hz, CH2), 31.0 (d, J(P,C) = 18.5 Hz, CH), 31.7
(s, CH2), 33.5 (d, 2,3J(P,C) = 4.3 Hz, CH2), 68.4 (d, 1J(P,C) = 23.6 Hz,
ipso-C), 195.6 (d, 2J(P,C) = 8.6 Hz, cis-CO), 198.2 (d, 2J(P,C) = 32.9 Hz,
Crystal Data for 5a. Suitable single crystals of 5a were obtained
from a concentrated n-pentane solution on cooling to À20 °C. Data
were collected with a Nonius KappaCCD diffractometer equipped with
a low-temperature device at 100 K by using graphite-monochromated
Mo Kα radiation (λ = 0.710 73 Å). The structure was solved by
Patterson methods (SHELXS-97)17a and refined by full-matrix least
squares on F2 (SHELXL-97):17b C16H25O6PSi2W, Mr = 584, colorless,
1
trans-CO); 31P{1H} NMR δ 46.9 (1J(P,W) = 296.3 Hz); H NMR δ
0.22 (s, 9H, Si(CH3)3), 0.33 (s, 9H, Si(CH3)3), 1.33 (d, 1H, 2J(P,H) =
4.5 Hz, CH), 2.37À2.53 (m, 2H, CH2), 2.52À2.68 (m, 2H, CH2),
2.77À2.95 (m, 2H, CH2); 29Si{1H} NMR δ À1.3 (d, 2J(P,Si) = 5.4 Hz,
SiMe3), 1.0 (d, 2J(P,Si) = 8.3 Hz, SiMe3).
5639
dx.doi.org/10.1021/om200431f |Organometallics 2011, 30, 5636–5640

Organometallics
ARTICLE
crystal dimensions 0.480 Â 0.440 Â 0.420 mm3, triclinic, space group
P1, Z = 4, a = 10.7439(3) Å, b = 15.2447(3) Å, c = 16.2191(4) Å, α =
113.9990(12)°, β = 102.9220(13)°, γ = 99.5701(13)°, V = 2264.55(10)
Å3, Dexptl = 1.714 g cmÀ3, μ = 5.303 mmÀ1, T = 123(2) K, transmission
factors (min/max) 0.0937/0.1077, analytical absorption correction
based on the indexing of the crystal faces,17 2θmax= 5460°, 10 633
uniquedata, Rint = 0.0493, R1 (for I > 2σ(I)) = 0.0241, wR2 (for all data) =
0.0585, final R = 0.0241, goodness of fit 1.015, ΔF(max/min) = 1.087/
(5) Hung, J.-T.; Yang, S.-W.; Gray, G. M.; Lammertsma, K. J. Org.
Chem. 1993, 58, 6786.
(6) A P-imino derivative of I having a σ4,λ5-phosphorus was
reported by: Barion, D.; David, G.; Link, M.; Niecke, E. Chem. Ber.
1983, 126, 649.
(7) (a) Weber, L.; L€ucke, E.; Boese, R. Organometallics 1988, 7, 978.
(b) A 1,4-diphosphaspiropentane ligand was described by: Tran Huy,
N. H.; Salemkour, R.; Bartes, R.; Ricard, L.; Mathey, F. Tetrahedron
2002, 58, 7191.
(8) A derivative of I is also known in a nonligated fashion if
embedded in a phospha[7]triangulane; see: Slootweg, J. C.; Schakel,
M.; de Kanter, F. J. J.; Ehlers, A. W.; Kozhkushkov, S. I.; de Meijere, A.;
Lutz, M.; Spek, A. L.; Lammertsma, K. J. Am. Chem. Soc. 2004, 126, 3050.
(9) Baudler, M.; Leonhardt, W. Angew. Chem., Int. Ed. Engl. 1983,
22, 632.
À1.490 e ÅÀ3
.
Crystal Data for 6. Suitable single crystals of complex 6 were
obtained from a concentrated n-pentane solution on cooling to À20 °C.
Data were collected with a Nonius KappaCCD diffractometer equipped
with a low-temperature device at 100 K by using graphite-monochro-
mated Mo Kα radiation (λ = 0.710 73 Å). The structure was solved by
Patterson methods (SHELXS-97)17a and refined by full-matrix least
squares on F2 (SHELXL-97):17b C27H29O6PSi2W, Mr = 721, colorless,
crystal dimensions 0.60 Â 0.60 Â 0.40 mm3, monoclinic, space group
P21/n, Z = 4, a = 9.4702(4) Å, b = 11.4948(5) Å, c = 27.2741(12) Å, α =
90°, β = 97.782(2)°, γ = 90°, V = 2941.7(2) Å3, Dexptl = 1.627 g/cm3, μ =
4.100 mmÀ1, T = 123(2) K, transmission factors (min/max) 0.1923/
0.2908, analytical absorption correction based on the indexing of the
crystal faces, 2θmax = 56.0°, no. of unique data 7097, Rint = 0.0507, R1
(for I > 2σ(I)) = 0.0459, wR2 (for all data) = 0.1064, final R = 0.0429,
(10) Krahe, O.; Neese, F.; Streubel, R. Chem. Eur. J. 2009, 15, 2594.
(11) (a) Pꢀerez, J. M.; Helten, H.; Donnadieu, B.; Reed, C.; Streubel,
R. Angew. Chem., Int. Ed. 2010, 49, 2615. (b) Pꢀerez, J. M.; Albrecht, C.;
Helten, H.; Schnakenburg, G.; Streubel, R. Chem. Commun. 2010, 46,
7244–7246.
€
(12) (a) Ozbolat, A.; von Frantzius, G.; Pꢀerez, J. M.; Nieger, M.;
Streubel, R. Angew. Chem., Int. Ed. 2007, 46, 9327. (b) Foroxaphosphirane
W(CO)5 complexes, see: Bode, M.; Pꢀerez, J. M.; Schnakenburg, G.;
Daniels, J.; Streubel, R. Z. Anorg. Allg. Chem. 2009, 635 (8), 1163. (c) For
oxaphosphirane Cr(CO)5 and Mo(CO)5 complexes, see: Albrecht, C.;
Bode, M.; Pꢀerez, J. M.; Schnakenburg, G.; Streubel, R. Dalton Trans.
2011, 40, 2654.
(13) Khan, A. A.; Wismach, C.; Jones, P. C.; Streubel, R. Dalton
Trans. 2003, 12, 2483.
(14) For example, atropisomerism in P-heterocyclic ligands has been
observed before in 2H-1,2,4-diazaphosphole complexes; see: Streubel,
R.; Schiemann, U.; Tran Huy, N. H.; Mathey, F. Eur. J. Inorg. Chem.
2001, 3175.
goodness of fit 1.135, ΔF(max/min) = 3.59/À2.740 e ÅÀ3
.
Crystallographic data for 4a, 5a, and 6 have been deposited at the
Cambridge Crystallographic Data Centre under the numbers CCDC
806111(4a), CCDC 806112 (5a), and CCDC 806113 (6). These data
can be obtained free of charge from the Cambridge Crystallographic
Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
’ ASSOCIATED CONTENT
(15) Fankel, S.; Helten, H.; von Frantzius, G.; Schnakenburg, G.;
Daniels, J.; Chu, V.; M€uller, C.; Streubel, R. Dalton Trans. 2010, 39,
3472.
(16) Tran Huy, N. H.; Donnadieu, B.; Bertrand, G.; Mathey, F.
Organometallics 2010, 29, 1302.
S
Supporting Information. CIF files giving crystallo-
b
graphic data for 4a, 5a, and 6. This material is available free of
charge via the Internet at http://pubs.acs.org.
(17) (a) SHELXS-97: Sheldrick, G. M. Acta Crystallogr., Sect. A
1990, 46, 467. (b) Sheldrick, G. M. SHELXL-97; University of
G€ottingen: G€ottingen, Germany, 1997.
’ AUTHOR INFORMATION
Corresponding Author
*E-mail: r.streubel@uni-bonn.de. Fax: (+) 49-228-73-9616.
’ ACKNOWLEDGMENT
We are grateful to the Deutsche Forschungsgemeinschaft
(STR 411/29-1) and the COST action cm0802 “PhoSciNet”
for financial support; we are also thankful to Carolin Albrecht for
measuring the temperature-dependent NMR spectra in the case
of complexes 3a,b.
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