Reactivity of the labile complex [MoCl(η3-allyl)(CO) 2(NCMe)2] with diphosphanes

Article abstract of DOI:10.1039/b300350g

The reactions of [MoCl(η³-allyl)(CO)₂(NCMe) ₂] (1) with variable ratios of bis(dimethylphosphanyl)methane (dmpm) or bis(diphenylphosphanyl)methane (dppm) afford different products, in which the diphosphanes are acting either as a chelate, as in [MoCl(η³- allyl)(CO)₂(P-P)] (P-P = dmpm 2, dppm 6) and [Mo(NCMe) (η³-allyl)(CO)₂(P-P)]-[{Mo(η³-allyl) (CO)₂}₂(μ-Cl)₃] (P-P = dmpm 4, dppm 8) or as a bridge as in [{Mo(η³-allyl)(CO)₂} ₂(μ-Cl)₂(u-P-P)] (P-P = dmpm 3, dppm 7). The analogous reaction with tetraethyldiphosphite (tedip) affords [{Mo(η³- allyl)(CO)₂}₂(μ-Cl)₂(μ-tedip)] (5) as a single product. The Royal Society of Chemistry 2003.

Full text of DOI:10.1039/b300350g

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Reactivity of the labile complex [MoCl(ꢀ3-allyl)(CO)2(NCMe)2]
with diphosphanes
Julio Pérez,*a Dolores Morales,a Víctor Riera,a Amor Rodrígueza and
Santiago García-Grandab
a Departamento de Química Orgánica e Inorgánica/IUQOEM, Facultad de Química,
Universidad de Oviedo-C.S.I.C., Oviedo, E-33071, Spain.
E-mail: japm@sauron.quimica.uniovi.es; Fax: 34 985 103446
b Departamento de Química Física y Analítica, Facultad de Química,
Universidad de Oviedo-C.S.I.C., Oviedo, E-33071, Spain
Received 10th January 2003, Accepted 26th February 2003
First published as an Advance Article on the web 10th March 2003
The reactions of [MoCl(η3-allyl)(CO)2(NCMe)2] (1) with variable ratios of bis(dimethylphosphanyl)methane (dmpm)
or bis(diphenylphosphanyl)methane (dppm) afford different products, in which the diphosphanes are acting either
as a chelate, as in [MoCl(η3-allyl)(CO)2(P–P)] (P–P = dmpm 2, dppm 6) and [Mo(NCMe)(η3-allyl)(CO)2(P–P)]-
[{Mo(η3-allyl)(CO)2}2(µ-Cl)3] (P–P = dmpm 4, dppm 8) or as a bridge as in [{Mo(η3-allyl)(CO)2}2(µ-Cl)2(µ-P–P)]
(P–P = dmpm 3, dppm 7). The analogous reaction with tetraethyldiphosphite (tedip) affords [{Mo(η3-allyl)(CO)2}2-
(µ-Cl)2(µ-tedip)] (5) as a single product.
Introduction
We recently reported that the complex [MoCl(η3-allyl)(CO)2-
(dmpm)] (2) (dmpm = bis(dimethylphosphanyl)methane) reacts
with carbanionic reagents to afford the corresponding cis-
dicarbonyl [MoR(η3-allyl)(CO)2(dmpm)] complexes. These
species subsequently rearranged to the isomeric trans-dicarb-
onyl compounds, which then undergo the reductive elimination
of the R–allyl coupling products.1 We have prepared complex 2
by reaction of the known precursor [MoCl(η3-allyl)(CO)2-
(NCMe)2] (1)2 with dmpm, a method that has become con-
ventional for the preparation of [MoCl(η3-allyl)(CO)2(L–L)]
(L–L = bidentate ligand) compounds.3 However, we observed
that traces of other species were formed in addition to complex
2 in some of the preparations. Having ruled out the presence of
an impurity in the reagents, we hypothesized that compounds
with a molybdenum : dmpm ratio different from 1 : 1 were
Fig. 1 Thermal ellipsoid plot (30% probability) and numbering
formed along with complex 2. Thus, we initiated a careful study
of the reaction of the bis(nitrile) complex 1 with dmpm. Our
findings are the subject of this paper.
scheme of 3. Selected lengths (Å) and angles (Њ): Mo–Mo 4.027(4),
Mo–Cl(1) 2.627(1), Mo–Cl(2) 2.627(1); Cl(2)–Mo–Cl(1) 79.10(4).
The molecule of 3 possesses a mirror plane orthogonal to
the intermetallic vector. The 1H and 31P NMR data (see
Experimental section) are consistent with this structure being
maintained in solution.
When the reaction of 1 and dmpm was carried out using
an Mo : dmpm ratio of 3 : 1, the compound [Mo(NCMe)-
(η3-allyl)(CO)2(dmpm)][{Mo(η3-allyl)(CO)2}2(µ-Cl)3] (4) was
the major product. Selective crystallization allowed its iso-
Results and discussion
The reaction of [MoCl(η3-allyl)(CO)2(NCMe)2] (1)2 with
an equimolar amount of dmpm afforded [MoCl(η3-allyl)-
(CO)2(dmpm)] (2),1 which could be isolated in high yield by
crystallization. However, the reactions of 1 with substoichio-
metric amounts of dmpm yielded solutions containing two new
compounds in ratios dependent of the amount of dmpm used
(Scheme 1). Working with a Mo : dmpm ratio of 2 : 1, complex
[{Mo(η3-allyl)(CO)2}2(µ-Cl)2(µ-dmpm)] (3) was obtained as the
major product and could be isolated by fractional crystalliz-
ation. A yellow single crystal of 3 was used for a structural
determination by X-ray diffraction. The results are displayed in
Fig. 1.
lation, and
a structural determination was carried out
using single-crystal X-ray diffraction. The results are displayed
in Fig. 2.
Compound 4 is a salt whose anion, consisting of two cis-
{Mo(η3-allyl)(CO)2} fragments linked by three chloro bridges,
was previously found in the compound [Mo(η3-allyl)(CO)2-
(NCMe)3][{Mo(η3-allyl)(CO)2}2(µ-Cl)3].6 The cation of 4 is a
monometallic complex with an acetonitrile and a chelating
dmpm ligand bonded to a {Mo(η3-allyl)(CO)2} fragment.7
Obviously, the formation of 4 is the result of ionization and
intermolecular chloride transfer. This has also been found to be
the case in the generation of the mentioned salt [Mo(η3-allyl)-
(CO)2(NCMe)3][{Mo(η3-allyl)(CO)2}2(µ-Cl)3] when the labile
precursor 1 stands in solution of non-coordinating solvents
prolonged times.6 However, there should be noted that the
formation of the salt 4 upon reaction of 1 with dmpm is
The molecule of 3 consists of two identical cis-{Mo-
(η3-allyl)(CO)2} moieties linked by two chloro bridges and a
dmpm bridge. Each metal center is electron precise without
considering an intermetallic bond; consistently, the Mo–Mo
distance (4.027(4) Å) is outside the range of direct Mo–Mo
bonds.4
The open face of the allyl group on each metal fragment is
oriented pointing toward the carbonyls, as found for most
mononuclear [MoCl(η3-allyl)(CO)2(L–L)] derivatives.5
T h i s j o u r n a l i s © T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 3
D a l t o n T r a n s . , 2 0 0 3 , 1 6 4 1 – 1 6 4 4
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Scheme 1
Fig. 2 Thermal ellipsoid plot (30% probability) and numbering scheme of 4. Selected bond lengths (Å) and angles (Њ): Mo(1)–Cl(1) 2.519(2),
Mo(1)–Cl(2) 2.596(2), Mo(1)–Cl(3) 2.580(3), Mo(2)–Cl(1) 2.566(2), Mo(2)–Cl(2) 2.538(2), Mo(2)–Cl(3) 2.580(2), Mo(1)–C(1) 1.931(10),
Mo(3)–N(80) 2.220(8); Mo(3)–N(1) 2.212(8), Mo(3)–P(1) 2.458(3), Mo(3)–P(2) 2.463(3), Cl(3)–Mo(2)–Cl(2) 78.20(7), Cl(1)–Mo(2)–Cl(2) 78.03(7),
Cl(2)–Mo(1)–Cl(3) 79.39(8), Cl(1)–Mo(1)–Cl(3) 77.64(8), N(1)–Mo(3)–P(1) 91.8(2), N(1)–Mo(3)–P(2) 91.5(2), P(1)–Mo(3)–P(2) 66.59(9).
instantaneous. This suggests that the presence of the strongly
donating dmpm ligand promotes the ionization.
Using 31P NMR, we have examined how the composition of
the mixtures obtained by reaction of 1 and dmpm changes with
time. We found that the final formation of the dmpm-bridged
bimetallic complex 3 takes place, at least in part, at the expense
of the salt 4, which, even using a Mo : dmpm ratio of 2 : 1, is
initially formed as the major product. The formation of 3 from
4 implies, besides chloride transfer between molybdenum cen-
ters, a change in the coordination mode of dmpm, a process
that is known to be facile for this diphosphane.8 Although
slower than the formation of 3 from 4, 31P NMR monitoring
indicated that, in the presence of excess of dmpm, the binuclear
complex 3 transforms into 2.
Scheme 2
We reasoned that using a diphosphane which is both a
poor donor and a good binucleating ligand would favor the
formation of a bridged bimetallic complex like 3. To test this
idea, we have chosen tetraethyldiphosphite (tedip), which is a
weaker donor than bis(dialkylphosphanyl)alkanes and shows a
high preference for the bridging over the chelate coordination
mode. Indeed, the reaction of 1 with tedip yielded, regardless of
the Mo : tedip ratio, complex [{Mo(η3-allyl)(CO)2}2(µ-Cl)2-
(µ-tedip)] (5) (Scheme 2), which was found to be isostructural
with 3 by the results of a single crystal X-ray determination,
shown in Fig. 3.
Compounds 3 and 5 are the first examples of diphosphane-
bridged complexes with pseudo-octahedral {Mo(η3-allyl)-
(CO)2} moieties.
The formation of similar species in the reactions of 1 with
bis(diphenylphosphanyl)methane (dppm), which have been
previously used to prepare the well known [MoCl(η3-allyl)-
Fig. 3 Thermal ellipsoid plot (30% probability) and numbering
scheme of 5. Selected lengths (Å) and angles (Њ): Mo–Mo 3.985(2),
Mo–Cl(1) 2.592(2), Mo–Cl(2) 2.588(3); Cl(2)–Mo–Cl(1) 79.45(6).
D a l t o n T r a n s . , 2 0 0 3 , 1 6 4 1 – 1 6 4 4
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(CO)2(dppm)]3c complex, was not investigated previously. We
set out to explore the possible presence of these species in the
crude reaction mixtures obtained from 1 and dppm. Faller et al.
reported the preparation of [MoCl(η3-allyl)(CO)2(dppm)] by
reaction of 1 with dppm followed by chromatographic purifi-
cation.3c Accordingly, we found that using a Mo : dppm ratio of
1 : 1, the main product (as shown by the 31P NMR spectrum)
was [MoCl(η3-allyl)(CO)2(dppm)] (6), characterized by X-ray
diffraction (Fig. 4) (Scheme 1). The structure of 6 is, in the
main, similar to that of the previously characterized 1,2-di-
phenylphosphanylethane (dppe) derivative [MoCl(η3-allyl)-
(CO)2(dppe)].3c In addition, we have observed signals due to
two minor products in the 31P NMR spectra of the crude mix-
tures present before chromatography. The relative amount of
these byproducts increased when Mo : dppm ratios of 2 : 1 or
3 : 1 were employed. One of these species, featuring a singlet
at Ϫ2.33 ppm, was found to be the kinetic product and, by
analogy with the results obtained with dmpm (vide supra), was
believed to be the salt [Mo(NCMe)(η3-allyl)(CO)2(dppm)]-
[{Mo(η3-allyl)(CO)2}2(µ-Cl)3] (8). 31P NMR monitoring of the
reaction mixtures showed an increase of two additional
compounds featuring singlets at 13.02 and Ϫ2.03 ppm. The
latter corresponds to the mononuclear complex 6 (vide supra).
The former could be obtained as the main product using a
Mo : dppm ratio of 2 : 1. This product was found to be
[{Mo(η3-allyl)(CO)2}2(µ-Cl)2(µ-dppm)] (7) by X-ray diffraction
(see Fig. 5). The main features of the structure of 7 are similar
to those of 3 (vide supra). The interconversions of 6, 7 and 8
parallel those found for the dmpm analogs (see above).
In conclusion, the present work indicates that widely used
diphosphanes act both as chelates and as bridges toward
{Mo(η3-allyl)(CO)2} fragments, and that chloride transfer, ion-
ization and binucleation can occur readily in solution. The
existence of these processes can be of relevance when studying
the solution behavior of [MoX(η3-allyl)(CO)2(P–P)] complexes,
which have been used as allylic alkylation precatalysts.9
Experimental
All operations were carried out under an atmosphere of dry
dinitrogen using Schlenk techniques. Solvents were dried over
Na (hexane), CaH2 (CH2Cl2 and MeOH) and distilled immedi-
ately before being used. IR spectra were registered in THF
solutions. NMR chemical shifts (δ) are given in ppm, and
coupling constants (J) in Hz. Apparent triplet is abbreviated
“at” in the 1H NMR spectra. All spectra were recorded at room
temperature.
Preparation of [MoCl(ꢀ3-C3H5)(CO)2(dmpm)] (2)
The addition of dmpm (50 µL, 0.32 mmol) to [MoCl-
(η3-C3H3)(CO)2(NCMe)2] (1)2 (0.10 g, 0.32 mmol) in CH2Cl2
(10 mL) gave a red solution which was stirred for 5 min. The
volume was reduced in vacuo to one third and hexane was
added to precipitate 2 as an orange crystalline solid. Yield: 0.11
g, 94%; Anal. Calc. for C10H19ClMoO2P2: C, 32.94; H, 5.25.
Found C, 32.61; H, 5.62%. IR (νCO) (CH2Cl2): 1944s, 1845s
cmϪ1; 1H NMR (CD2Cl2): δ 1.65 [at, 2JP–H = 5, 6H, CH3 dmpm],
2
3
1.73 [at, JP–H = 5, 6H, CH3 dmpm], 2.31 [d, JH–H = 12, 2H,
Hanti], 3.24 [m, 2H, CH2 dmpm], 3.69 [m, 2H, Hsyn], 4.75 [m, 1H,
1
C2H]. 13C{1H} NMR (CD2Cl2): δ 13.40 [at, JP–C = 13, CH3
dmpm], 17.34 [at, 1JP–C = 14, CH3 dmpm], 40.65 [at, 1JP–C = 23,
CH2 dmpm], 62.36 [s, C1,3 allyl], 98.68 [s, C2 allyl], 226.68 [at,
2JP–C = 8, CO]. P{1H} NMR (CD2Cl2): δ Ϫ24.38.
Reaction of 1 with substoichiometric amounts of dmpm
(a) dmpm (25 µL, 0.16 mmol) was added to a solution of 1 (0.10
g, 0.32 mmol) in CH2Cl2 (20 mL) and the mixture was stirred
for 15 min. The solution was concentrated to 5 mL and hexane
was added (20 mL), causing the precipitation of an orange solid
which was washed with hexane and dried in vacuo. By slow
diffusion of hexanes into a concentrated solution of the orange
solid in CH2Cl2 (5 mL) at Ϫ20 ЊC red crystals of 3 were
obtained. Yield: 0.05 g, 60%. Anal. Calc. for C15H24Cl2Mo2-
Fig. 4 Thermal ellipsoid plot (30% probability) and numbering
scheme of 6. Selected bond lengths (Å) and angles (Њ): Mo–Cl
2.5232(9), Mo–P(1) 2.5474(10), Mo–P(2) 2.6015(9), Mo–C(2) 1.973(3),
Mo–C(3) 1.941(3); P(1)–Mo–P(2) 64.47(3).
O4P2: C, 30.37; H, 4.07. Found: C, 30.14; H, 4.21%. IR (νCO
)
1
(CH2Cl2): 1934s, 1851s cmϪ1. H NMR (CD2Cl2): δ 1.82 [d,
3JH–H = 10.0, 4H, Hsyn], 1.88 [d, 2JH–P = 7.0, 12H, CH3 dmpm], 2.15
[t, 2JH–P = 12, 2H, CH2 dmpm], 3.71 [d, 3JH–H = 7.0, 4H, Hanti], 4.68
[m, 2H, C2H]. 31P{1H} NMR (CD2Cl2): δ Ϫ2.29.
(b) dmpm (16 µL, 0.10 mmol) was added to a solution of 1
(0.10 g, 0.32 mmol) in CH2Cl2 (20 mL) and the mixture was
stirred for 15 min. The solution was concentrated to 5 mL,
layered with hexane (20 mL) and placed at Ϫ20 ЊC. After
several days, orange crystals of 4 were obtained. Yield: 0.03 g,
41%. Anal. Calc. for C22H32Cl3Mo3NO6P2: C, 28.33; H, 3.45.
Found: C, 28.26; H, 3.65%. IR (νCO) (CH2Cl2): 1992s, 1935s
1
cmϪ1. H NMR (CD2Cl2): cation [Mo(η3-allyl)(CO)2(NCMe)-
(dmpm)] δ 1.90 [m, 12H, CH3 dmpm], 2.40 [s, 3H, MeCN], 2.46
3
[d, JH–H = 12.13, 2H, Hanti], 3.17 [m, 2H, CH2 dmpm], 3.75 [d,
3JH–H = 6, 2H, Hsyn], 5.30 [m, 1H, C2H]. Anion [{Mo-
(η3-allyl)(CO)2}2(µ-Cl)3] δ 0.95 [d, 3JH–H = 9.6, 4H, Hanti], 3.46 [d,
3JH–H = 6.5, 4H, Hsyn], 3.80 [m, 2H, C2H]. 13C{1H} NMR
(CD2Cl2): Cation [Mo(η3-allyl)(CO)2(NCMe)(dmpm)] δ 4.52 [s,
1
NCCH3], 17.80 [m, CH3 dmpm], 41.71 [t, JC–H = 27.5, CH2
dmpm], 63.19 [s, C1,3 allyl], 108.55 [s, C2 allyl], 125.03 [s,
NCMe], 222.29 [s, CO]. Anion [{Mo(η3-allyl)(CO)2}2(µ-Cl)3]
δ 63.78 [s, C1,3 allyl], 83.28 [s, C2 allyl], 228.86 [s, CO]. 31P{1H}
NMR (CD2Cl2): δ Ϫ24.41.
Fig. 5 Thermal ellipsoid plot (30% probability) and numbering
scheme of 7. Selected bond lengths (Å) and angles (Њ): Mo(1)–Cl(1)
2.5793(11), Mo(1)–Cl(2) 2.6266(14), Mo(2)–Cl(1) 2.5789(13), Mo(2)–
Cl(2) 2.6177(11); Cl(2)–Mo–Cl(1) 78.85(5).
D a l t o n T r a n s . , 2 0 0 3 , 1 6 4 1 – 1 6 4 4
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Preparation of [{Mo(ꢀ3-C3H5)(CO)2}2(ꢁ-Cl)2(ꢁ-tedip)] (5)
mmϪ1, 2142 reflections measured, 2142 unique (Rint = 0.0287),
wR2 = 0.0918.
Tedip (0.16 mmol, 40 µL) was added to a solution of [MoCl-
(η3-C3H3)(CO)2(NCMe)2] (0.32 mmol, 0.10 g) in CH2Cl2
(20 mL). The color of the solution changed immediately from
yellow to red. The solution was concentrated in vacuo to 2 mL
and hexane was added, causing the precipitation of a red solid
which was washed with hexane and dried in vacuo. Yield: 0.20 g,
86%. Slow diffusion of hexanes onto a concentrated solution of
5 in THF afforded red crystals, one of which was used for a
structural determination by X-ray diffraction. Anal. Calc. for
C18H30Cl2Mo2O9P2: C, 30.23; H, 4.22. Found: C, 30.02; H,
4.53%. IR (νCO) (CH2Cl2): 1948s, 1863s cmϪ1. 1H NMR
4: C22H32Cl3Mo3NO6P2, M = 843.57, monoclinic, space
group P21/c, a = 9.6225(4), b = 16.2346(7), c = 21.4232(7) Å,
β = 93.951(2)Њ, U = 3338.7(2) Å3, T = 293 K, Z = 4, λ(Cu-Kα) =
1.54184 mmϪ1, 5465 reflections measured, 3526 unique
(Rint = 0.0675), wR2 = 0.1844.
5: C18H30Cl2Mo2O9P2,
M = 715.14, monoclinic, space
group P21/c, a = 10.050(7), b = 11.580(9), c = 23.320(11) Å,
β = 97.82(3)Њ, U = 2689(3) Å3, T = 293 K, Z = 4, λ(Cu-Kα) =
1.54184 mmϪ1, 3961 reflections measured, 2992 unique
(Rint = 0.0672), wR2 = 0.1726.
6: C34H35ClMoO3P2,
M = 684.95, monoclinic, space
2
3
(CD2Cl2): δ 1.43 [t, JH–P = 7, 12H, CH3], 1.83 [d, JH–H = 10.7,
group P21/c, a = 15.119(5), b = 10.830(5), c = 23.494(5) Å,
β = 123.229(5)Њ, U = 3218(2) Å3, T = 293 K, Z = 4, λ(Cu-Kα) =
1.54084 mmϪ1, 11578 reflections measured, 6058 unique
(Rint = 0.0365), wR2 = 0.0863.
7: C36H33Cl2NMo2O4P2, M = 868.35, monoclinic, space
group P21/c, a = 14.763(5), b = 15.343(5), c = 17.538(5) Å,
β = 114.96(5)Њ, U = 3601(2) Å3, T = 293 K, Z = 4, λ(Cu-Kα) =
1.54184 mmϪ1, 6752 reflections measured, 6752 unique
(Rint = 0.0375), wR2 = 0.0836.
3
4H, Hanti], 3.82 [d, JH–H = 6.7, 4H, Hsyn], 3.90 [m, 8H, CH2],
4.49 [m, 2H, C2H]. 13C NMR (CD2Cl2): δ 16.46 [s, CH3],
62.99 [s, CH2], 64.83 [s, C1,3 allyl], 74.09 [s, C2 allyl], 223.57 [at,
3JC–P = 7.9, CO]. 31P{1H} NMR (CD2Cl2): δ 127.29.
Reaction of 1 with dppm
A mixture of dppm (0.24 mmol, 0.09 g) and [MoCl(η3-C3H5)-
(CO)2(NCMe)2] (1) (0.48 mmol, 0.15 g) was charged in a
Schlenk flask along with a stirbar. After three vacuum–nitrogen
cycles, CH2Cl2 (30 mL) was added. NMR samples were taken at
1 h intervals by charging 0.5 mL amounts of this reaction mix-
ture into 5 mm NMR tubes containing capillary inserts filled
with D2O as lock signal. 31P NMR monitoring indicated initial
(1 h) predominance of [MoCl(η3-allyl)(CO)2(dppm)] (6) (singlet
at Ϫ2.03 ppm) and small amounts of [{Mo(η3-C3H5)(CO)2}2-
(µ-Cl)2(µ-dppm)] (7) and [Mo(NCMe)(η3-C3H5)(CO)2(dppm)]-
[{Mo(η3-C3H5)(CO)2}2(µ-Cl)3] (8) (singlets at 13.02 and Ϫ2.33
ppm, respectively). After 1 day, the mixture contains similar
amounts of 6 and 7 and a small amount of 8. After 1 week the
major product (approximately 70%) is 7. At this point the
orange solution was filtered through diatomaceous earth, con-
centrated to a volume of 5 mL and layered with hexane. A
mixture of yellow crystals of 6 and orange crystals of 7 was
obtained, which were separated by hand under a microscope
and characterized by NMR spectroscopy and X-ray diffraction.
The spectroscopic data of 6 coincide with those reported by
Faller et al.3c
CCDC reference numbers 196132–196136.
See http://www.rsc.org/suppdata/dt/b3/b300350g/ for crystal-
lographic data in CIF or other electronic format.
Acknowledgements
We thank Ministerio de Ciencia
y Tecnología (grants
BQU2000-0220 and BQU2000-0219) and Principado de
Asturias (grants PR-01-GE-7 and PR-01-GE-4) for support
of this work.
References
1 J. Pérez, V. Riera, A. Rodríguez and S. García-Granda, Angew.
Chem., Int. Ed., 2002, 41, 1427.
2 H. tom Dieck and H. Friedel, J. Organomet. Chem., 1968, 14, 375.
3 (a) P. K. Baker, Adv. Organomet. Chem., 1996, 40, 46; (b) J. W.
Goodyear, C. W. Hemingway, R. W. Harrington, M. R. Wiseman
and B. J. Brisdon, J. Organomet. Chem., 2002, 664, 176; (c) of
particular relevance to the work reported here is the following paper,
which deals with the synthesis and characterization of diphosphane
complexes: J. W. Faller, D. A. Haitko, R. D. Adams and D. F.
Chodosh, J. Am. Chem. Soc., 1979, 114, 865; (d ) for a different way
to access Mo–allyl compounds see: A. G. W. Hodson, R. K. Thind
and M. McPartlin, J. Organomet. Chem., 2002, 664, 277.
4 S. W. Kirtley, in Comprehensive Organometallic Chemistry,
ed. G. Wilkinson, F. G. A. Stone and E. Abel, Pergamon, Oxford,
1982, vol. 3, p. 1091.
7: Yield: 0.13 g, 64%. Anal. Calc. for C35H32Cl2Mo2O4P2: C,
49.96; H, 3.83. Found C, 49.79; H, 3.75%. IR (νCO) (CH2Cl2):
1
3
1940vs, 1854s cmϪ1; H NMR (CD2Cl2): δ 1.74 [d, JH–H = 10,
4H, Hanti], 3.52 [t, 2JH–P = 11.5, 2H, CH2 dppm], 3.85 [d, 3JHH = 7,
4H, Hsyn], 4.66 [m, 2H, C2H], 7.29 [m, 20H, Ph of dppm].
31P{1H} NMR (CD2Cl2): δ 13.20.
5 M. D. Curtis and O. Eisenstein, Organometallics, 1984, 3, 887.
6 (a) M. G. Drew, B. J. Brisdon and M. Cartwright, Inorg. Chim.
Acta., 1979, 36, 127; (b) for other compounds with this bimetallic
anion, see: P. Pinto, E. Barranco, M. J. Calhorda, V. Félix and
M. G. B. Drew, J. Organomet. Chem., 2000, 601, 34.
X-Ray crystallographic study
Data in common: Bruker AXS SMART 1000 CCD diffract-
ometer, ꢀ and ω scans, Mo-Kα radiation (λ = 0.71073 Å),
graphite monochromator, T = 295 K. Raw frame data were
integrated with the SAINT10 program. Structures were solved
by direct methods with SHELXTL.11 Semi-empirical absorp-
tion correction was done with SADABS.12 All non-hydrogen
atoms were refined anisotropically. Hydrogen atoms were set in
calculated positions and refined as riding atoms, with a com-
mon thermal parameter. All calculations were made with
SHELXTL.
7 For examples of crystallographically characterized [Mo(η3-allyl)-
(NCMe)(CO)2(P–P)]ϩ compounds, see: (a) G.-H. Lee, S.-M. Peng,
F.-Ch. Liu, D. Mu and R.-S. Liu, Organometallics, 1989, 8, 402;
(b) S.-F. Lush, S.-H. Wang, G.-H. Lee, S.-M. Peng, S.-L. Wang and
R.-S. Liu, Organometallics, 1990, 9, 1862.
8 F. A. Cotton, E. V. Dikarev and S. Herrero, Inorg. Chem., 1999, 38,
490.
9 B. M. Trost and M. Lautens, J. Am. Chem. Soc., 1982, 104, 5543.
10 SAINTϩ. SAX area detector integration program. Version 6.02.
Bruker AXS, Inc. Madison, WI, 1999.
11 G. M. Sheldrick, SHELXTL, an integrated system for solving,
refining, and displaying crystal structures from diffraction data.
Version 5.1. Bruker AXS, Inc. Madison, WI, 1998.
12 G. M. Sheldrick, SADABS, Empirical Absorption Correction
Program, University of Göttingen, Göttingen, Germany, 1997.
Crystal data
3: C15H24Cl2Mo2O4P2, M = 593.06, orthorhombic, space
group Pnma, a = 11.8955(11), b = 19.191(6), c = 9.294(2) Å,
U = 2121.8(9) Å3, T = 293 K, Z = 4, λ(Mo-Kα) = 0.71073
D a l t o n T r a n s . , 2 0 0 3 , 1 6 4 1 – 1 6 4 4
1644