Synthesis of a functional C2-symmetrical bidentate diphenylphosphonite diop derivative and its conversion into the corresponding π-acidic bis(pentafluorophenyl) and bis(p-tetrafluoropyridyl) compounds

Article abstract of DOI:10.1002/chem.200600260

The reaction of a C₂-symmetric diiodo compound, 1,4-dideoxy-1,4-diiodo-2,3,-O-isopropyliden-L-threitole, with [K([18]crown-6)]P(CN)₂ led to the generation of a corresponding bidentate dicyanophosphorus derivative. The in situ reactio

Full text of DOI:10.1002/chem.200600260

FULL PAPER
DOI: 10.1002/chem.200600260
Synthesis of a Functional C2-Symmetrical Bidentate Diphenylphosphonite
DIOPDerivative and Its Conversion into the Corresponding p-Acidic
Bis(pentafluorophenyl) and Bis(p-tetrafluoropyridyl) Compounds**
[a]
Berthold Hoge* and Patricia Panne
Dedicated to Professor Josef Hahn on the occasion of his 65th birthday
Abstract: The reaction of a C2-symmet-
ric diiodo compound, 1,4-dideoxy-1,4-
diiodo-2,3,-O-isopropyliden-l-threitole,
with [K([18]crown-6)]P(CN)2 led to the
generation of a corresponding biden-
tate dicyanophosphorus derivative. The
in situ reaction with excess methanol
and phenol yielded the corresponding
bidentate dimethyl- and diphenylphos-
phonites, respectively. The isolated liq-
uids were characterized by multinu-
clear NMR spectroscopy, elemental
analysis, and mass spectrometry. The
bidentate diphenylphosphonite ligand
(a diphenoxyphosphane derivative)
represents one of the very few func-
tional bidentate phosphane derivatives:
a DIOP [(2,2-dimethyl-1,3-dioxolane-
4,5-diyl)bis(methylene)]bis(diphenyl-
phosphane) modification, in which the
phenyl groups at the phosphorus atoms
are replaced by functional phenoxy
groups. Treatment of the bidentate di-
phenylphosphonite derivative with
C6F5MgBr and p-C5NF4MgBr allowed
the isolation and full characterization
of the comparable bidentate bis(penta-
fluorophenyl) and bis(p-tetrafluoropyr-
idyl)phosphanes. The ligand properties
of the novel bidentate ligand systems
were evaluated through the synthesis
and vibrational investigation of their
tetracarbonyl–molybdenum and cyclo-
pentadienyl–iron complexes. The
p
acidity of the synthesized ligands in-
creases in the order methoxy-<phen-
AHCTREUNG
Keywords: chirality · Lewis acids ·
P
ligands
·
phos
A
·
phosphanide
Introduction
electron-poor phosphane ligands, containing electron-with-
drawing groups at the phosphorus atom, are desirable.[2]
Chiral, bidentate phosphane ligands, such as DIOP, [(2,2-
dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene)]bis(diphenyl-
phosphane), are usually prepared by reacting chiral 1,2-, 1,3-
, or 1,4-ditosylates with diarylphosphanides,[3] as shown in
Equation (1):
Chiral, bidentate phosphane ligands play an important role
in asymmetric catalysis. The main activities in the develop-
ment of chiral phosphane ligands with catalytic efficiency
are focused on the variation of the so-called chiral back-
bone.[1] The aim of our work is a systematic variation of the
phosphorus substituents for one given chiral backbone. This
kind of variation should allow a fine tuning of the catalytic
activity of the corresponding chiral phosphane transition-
metal complexes by the steric and electronic effects of the
phosphorus atom bearing different substituents. Because
Lewis acids play a key role as catalysts in organic synthesis,
By applying this procedure to the synthesis of a bis(tri-
[a] Priv.-Doz. Dr. B. Hoge, Dr. P. Panne
Institut für Anorganische Chemie, Universität zu Kçln
Greinstr. 6, 50939 Kçln (Germany)
Fax : (+49)221-470-5196
fluoromethyl)phosphane chelate ligand 3 [Eq. (2)], we in-
ꢀ
vestigated the stabilization of the P
A
ence of acetone, which allowed the synthesis of the first ex-
ample of bidentate bis(perfluoroorganyl)phosphane
a
E-mail: b.hoge@uni-koeln.de
ligand. The strong p acidity of the bidentate ligand was
[**] DIOP=[(2,2-dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene)]bis(di-
phenylphosphane)
demonstrated by conducting a structural and vibrational
Chem. Eur. J. 2006, 12, 9025 – 9035
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9025

The coordination properties of the bidentate phosphane
ligands 5–8 were evaluated by conducting a vibrational
study of the corresponding tetracarbonyl–molybdenum and
cyclopentadienylcarbonyl–iron complexes.
analysis of
complex.[4]
a
corresponding tetracarbonyl–molybdenum
Results and Discussion
With the aim of synthesizing a corresponding bis(penta-
In the literature, three examples of functional phosphanides
are described that are, in principal, useful for the synthesis
of chiral, bidentate phosphane derivatives, such as 4. These
fluorophenyl) derivative we investigated the stabilization of
ꢀ
the P
A
ꢀ
ꢀ
as Hg2+ ions,[5] as well as CS2.[6] However, all attempts to
are the well-known, strongly basic PH2 and P
ions, and the less-basic P(CN)2 ion.
A
ꢀ
carry out the desired substitution of iodine by P
groups have been unsuccessful.[7]
A
Application of the dicyanophosphanide ion would result
in the synthesis of dicyanophosphane derivatives. As demon-
strated previously, dicyanophosphanes can be transformed
easily into the corresponding bis(trifluoromethyl)- and bis-
To allow the synthesis of a whole series of chiral, biden-
tate bis(perfluoroorganyl)phosphane derivatives, the appli-
ꢀ
cation of a phosphanide derivative, PX2 , with functional
groups X that can be replaced by other nucleophilic groups,
seems to be favorable. The adoption of a functional phos-
phanide, PX2 , would result in the synthesis of a functional
C
ꢀ
bidentate phosphane derivative 4 that should be capable of
transformation into different phosphane derivatives.
Here, we report the application of the dicyanophospha-
PhPðCNÞ2 þ 2 Me3SiRf !PhPðRfÞ2 þ 2 Me3SiCN
ð3Þ
Rf ¼ CF3, C6F5
ꢀ
nide ion[8] P(CN)2 , which acts as a functional phosphanide
ꢀ
ꢀ
PX2 and allows the synthesis of phosphane derivative 4 and
The dicyanophosphanide ion, P(CN)2 , presented by
its corresponding diphenyl- and dimethylphosphonite deriv-
atives 5 and 6, respectively (Scheme 1).
Schmidpeter and co-workers in 1977, represents a stable, nu-
cleophilic, and functional phosphanide ion that can be ac-
cessed through the cyanide degeneration of white phospho-
rus [Eq. (4)]. The reaction of cyanides with P(CN)3 followed
by reductive elimination of dicyane [Eq. (5)] also gives
ꢀ
P(CN)2 salts. Reaction of P(CN)3 with diethylphosphonate
salts [Eq. (6)][8] is best suited for the preparative synthesis of
ꢀ
P(CN)2 salts.[10],,
n=4 P4 þ 2 CNꢀ ! PðCNÞ2 þ ðPnꢀ1Þꢀ
ð4Þ
ꢀ
PðCNÞ3 þ CNꢀ ! ½PðCNÞ4ꢁꢀ ! PðCNÞ2 þ NCꢀCN ð5Þ
ꢀ
PðCNÞ3 þ ðEtOÞ2POꢀ ! PðCNÞ2 þ NCPOðOEtÞ2
ð6Þ
ꢀ
In the classical synthesis of cyanophosphanes, chlorophos-
phanes are reacted with silver cyanide,[11] a process that is
cost-intensive and less useful for the synthesis of large
amounts of P(CN)3. However, a very convenient preparative
access to P(CN)3, on a 10-g scale, is given by the reaction of
PCl3 and HCN in the presence of triethylamine [Eq. (7)]:
PCl3 þ 3 HCN þ 3 NEt3 ! 3 ½NEt3HꢁCl þ PðCNÞ3
ð7Þ
Scheme 1. Strategy for the synthesis of chiral, electron-poor phosphane li-
gands 5–8.
ꢀ
The use of P(CN)2 salts in nucleophilic displacement re-
actions was investigated. Schmidtpeter and co-workers re-
ported the successful nucleophilic substitution of alkylha-
The diphenylphosphonite system 5 (a diphenoxyphos-
phane derivative) still exhibits the properties of a functional
phosphane. Upon treatment with pentafluorophenyl and p-
tetrafluoropyridyl Grignard reagents it can be transformed
into the corresponding bis(pentafluorophenyl) and bis(p-tet-
rafluoropyridyl) derivatives 7 and 8, respectively.
ꢀ
lides upon treatment with P(CN)2 salts. In our own investi-
gations we treated ethyl tosylate with [K([18]crown-
6)]P(CN)2, which led to EtP(CN)2 as the sole product in a
clean reaction. However, the less-reactive chiral ditosylate
derivative 1 exhibits no reaction upon treatment with
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Functional Bidentate Diphenylphosphonite Derivatives
FULL PAPER
ꢀ
P(CN)2 salts, whereas the rather more-reactive diiodo com-
Further evidence that compound 10 represents a phos-
phoranide is given by the resistance towards reaction with
Me3SiCF3 and Me3SiC6F5. To facilitate the synthesis of the
target bis(pentafluorophenyl) derivative 7 we tried to shift
the equilibrium between the products 9 and 10 [Eq. (9)] to-
wards the free compound 9, which should be capable of
transformation into the desired bis(pentafluorophenyl) de-
rivative 7. Unfortunately, the product ratio could be only
slightly influenced by solvent or temperature variations.
Even the addition of iodophilic Lewis acids, such as HgI2,
did not lead to a significant shift of the product ratio to-
wards the free compound 9. Because we were not able to
transform the products directly into the desired bis(penta-
fluorophenyl) derivative 7, we transformed compounds 9
and 10 into the corresponding phosphonite derivatives 5 and
6 by addition of excess phenol and methanol, respectively,
to the reaction mixture of the diiodo compound 2 and
[K([18]crown-6)]P(CN)2 [Eq. (10)].
pound 2 shows a smooth reaction upon treatment with
ꢀ
P(CN)2 salts.[12]
The synthesis of dicyanoorganylphosphanes through nu-
cleophilic substitution of iodide ions causes problems be-
cause the product tends to add the produced iodide ions
with formation of phosphoranide ions [Eq. (8)], as demon-
strated by Dillon and co-workers:[13]
NMR spectra of the reaction mixture from the reaction of
ꢀ
the diiodo compound 2 with P(CN)2 salts exhibit the reso-
ꢀ
nances of excess P(CN)2 at ꢀ193 ppm as well as two addi-
tional resonances at ꢀ70 and ꢀ90 ppm. The formation of
two reaction products could be explained by the formation
Saltlike compounds were separated from the reaction
mixtures by the addition of hexane. The separated solutions
were evaporated to yield the phosphonite derivatives conta-
minated with minor amounts of free crown ether. To
remove the crown ether, the crude product was dissolved in
a concentrated NaI solution in acetone to trap the crown
ether as its sodium complex. The phosphonite derivatives 5
and 6 were isolated in an overall yield of 77 and 79%, re-
spectively, in the form of colorless liquids that could be
easily manipulated by using standard Schlenk techniques.
Upon exposure to air, slow hydrolysis occurred, followed by
oxidation. The compounds were characterized by elemental
analysis, mass spectrometry, and multinuclear NMR spectros-
of dicyano(iodo)phosphoranides [Eq. (9)]. The assignment
G
of the product resonances is based on a comparison with the
resonances of dicyanomethylphosphane and the dicyano-
A
A
178.3 and 183.8 ppm, respectively, are within the typical
region for organyl phosphonite derivatives. The diastereo-
ꢀ
meric nature of the two OR groups attached at each phos-
phorus atom are apparent from the 13C NMR spectra. For
example, the two diastereomeric methyl groups of derivative
2
6 exhibit resonances at 54.3 and 54.7 ppm with J
A
plings of 12 and 13 Hz, respectively.
The two products 9 and 10 are formed in varying amounts.
Because the phosphorus-bonded phenoxy groups can be
replaced by various nucleophiles, compound 5 still repre-
sents a functional derivative that can react with pentafluoro-
phenyl and p-tetrafluoropyridyl Grignard reagents to form
the corresponding bis(pentafluorophenyl)phosphane and
bis(p-tetrafluoropyridyl) derivatives 7 and 8, [Eqs. (11) and
(12)]. Both compounds were obtained by an aqueous work-
up procedure, followed by liquid chromatography on silica
gel. They were recrystallized as white to pale-yellow solids
and were fully characterized.
The free dicyanophosphane derivative 9 always represents
the minor product, formed in less than 20% yield. The prod-
ucts can be separated from a stoichiometric reaction mixture
by slow addition of diethyl ether at ꢀ308C. The neutral di-
cyanophosphane derivative 9 remains in solution, however,
the salt 10 forms colorless crystals. Due to the extreme sen-
sitivity of the single crystals towards hydrolysis and oxygen,
we have not yet been able to characterize the product by
performing either structural or vibrational investigations.
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9027

B. Hoge and P. Panne
Product 7 was always contaminated by traces of a nona-
fluorobiphenyl derivative 7’ [Eq. (11)]. The formation of the
side product is caused by nucleophilic attack of excess
C6F5MgBr on a C6F5 group already attached at the phospho-
rus atom. A di- or oligomerization of the Grignard sub-
strate, C6F5MgBr, as observed to some extent for
C6F5MgCl,[14] seems to be unlikely. To reduce the amount of
7’ it was necessary to monitor
and 6 with [Mo(CO)4(nbd)] were complete within 3 h at
A
room temperature, whereas only 80% of the strongly p-
acidic ligands 7 and 8 were coordinated after 8 h at room
temperature. The complexes 5a–8a, as well as [Mo(CO)4-
(nbd)], are not stable in the reaction mixture, and an exten-
sion of the reaction time favors the formation of side prod-
ucts.
the addition of a freshly pre-
pared
Et2O
solution
of
C6F5MgBr to a solution of 5 in
THF by 31P NMR spectroscopy.
Stopping the addition directly
after a complete transformation
of 5 to 7 reduced the amount of
7’ to less than 1%.
The chemical difference between the two diastereomeric
pentafluorophenyl groups attached at each phosphorus atom
of the C2-symmetric ligand 7 causes the appearance of five
multiplets in the 19F NMR spectrum. The resonances of the
fluorine atoms in the para and meta positions of the two dia-
stereomeric C6F5 rings at around ꢀ150 and ꢀ160 ppm are
each separated by 0.3 ppm, whereas the two resonances of
the ortho fluorine atoms at ꢀ130 ppm could not be resolved.
The coordination of 7 to a Mo(CO)4 moiety increases the
chemical difference of the two diastereomeric C6F5 groups
in 7a. This results in a more-extended separation of the two
sets of ortho, meta, and para resonances in the 19F NMR
spectrum by 2.1, 1.2, and 3.7 ppm, respectively (Figure 1).
A more convenient method of preventing formation of
the nonafluorobiphenyl derivative 7’ is the deactivation of
the para position of the phenyl ring towards nucleophilic
substitution. The formation of the side products discussed,
such as 7’, can be excluded by an exchange of the para CF
unit by an isolobal nitrogen atom. The displacement of the
phenoxy groups of 5 by p-tetrafluoropyridyl groups is, there-
fore, selective. As expected, an excess of p-C5NF4MgBr[14,15]
does not lead to the formation of any side products.
Figure 1. 19F NMR spectrum of 7a (see text). Signals marked with aster-
isks belong to nonafluorobiphenyl derivatives [see 7’ in Eq. (10)].
Refluxing 7 with Mo(CO)6 in
acetonitrile or irradiation of a
solution in THF with a UV
lamp leads to the formation of
a dinuclear compound 7a’ with
a Mo(CO)5 moiety coordinated
at each phosphorus atom
[Eq. (14)]. For the dinuclear
To evaluate the coordination properties of the synthesized
p-acidic ligands 5–8, the corresponding tetracarbonyl–mo-
lybdenum complexes were synthesized by treating solutions
of the ligands in CH2Cl2 at room temperature with
compound 7a’ the two sets of the ortho, meta, and para
19F NMR resonances are separated by 1.3, 1.5, and 0.1 ppm,
respectively.
Surprisingly, the largest separation of the resonances be-
longing to the diastereomeric fluorine atoms of the mononu-
[Mo(CO)4(nbd)] (NBD=norbornadiene). The reactions of 5
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Functional Bidentate Diphenylphosphonite Derivatives
FULL PAPER
electron-withdrawing substituent. This interpretation is in
accordance with a recent quantum-chemical concept[7] that
ꢀ
uses the phosphorus carbon distances in corresponding aryl-
phosphanides, [ArPH]ꢀ, as an indicator for the evaluation
of the electron-withdrawing effect of aryl groups exerted on
a phosphorus atom. Corresponding quantum-chemical calcu-
lations at the B3PW91/6-311G(d,p) level of theory suggest
G
that the electron-withdrawing effect of perfluoroaryl groups
can be increased by a successive substitution of fluorine
atoms by CF3 groups, or made even stronger upon succes-
sive substitution of CF units by isolobal nitrogen atoms. By
considering these ideas the p-C5NF4 group was predicted to
be a stronger electron-withdrawing substituent than a C6F5
group, in accordance with the vibrational investigation of
tetracarbonyl–molybdenum complexes bearing p-C5NF4-
and C6F5-substituted phosphane ligands discussed above
(Table 1).
clear chelate complex 7a was observed for the fluorine
atoms in the para position. In contrast, the dinuclear com-
plex 7a’ exhibited the smallest chemical difference for the
para-oriented fluorine atoms.
The highest CO stretching modes of the mononuclear
complexes 5a–8a are listed in Table 1. As expected, the fre-
quencies of the carbonyl complexes are strongly dependent
The strong electron-withdrawing nature of the p-C5NF4
group (which exceeds that of a C6F5 group) effects an in-
creased stabilization of phosphinous acids, R2POH, with re-
spect to the tautomeric phosphane oxides, R2P(O)H.[23]
In contrast to the tetracarbonyl–molybdenum complexes
5a–8a that were synthesized to evaluate the coordination
properties of the correlated phosphane ligands, diphosphane
iron complexes are successfully used in homogeneous cataly-
sis.[24]
Table 1. Highest CO stretching mode of tetracarbonyl–molybdenum
complexes.
L2 with respect to 2L
2PF3
n˜(CO) [cmꢀ1
2087[16]
]
R
n˜(CO) [cmꢀ1
]
The achiral Lewis acid [Fe
(h5-C5H5)(CO)2
G
G
2074[17]
CF3
2073[4]
2063[18]
[Fe
ic activity.[27] However, upon substitution of PPh3 by the
stronger p-acidic P(OMe)3 ligand, the resulting complex [Fe-
(h5-C5H5)(CO)P
(OMe)3(thf)][BF4] does exhibit a catalytic
A
G
(thf)]
G
p-C5NF4
C6F5
2047
2041
2038
2031
2041[19]
AHCTREUNG
OPh
A
G
A
ACHTREUNG
2033[20]
2020[21]
2012[21]
OMe
activity towards Diels–Alder reactions.[27] This example
demonstrates the important influence of the substituents at
the phosphorus atoms on the catalytic activity of the result-
ing transition-metal phosphane complexes.
Ph/Ar[a]
2014–2018[22]
With the aim to synthesize potential catalytically active
chiral Lewis acids, the phosphane ligands 5–8 were reacted
[a] Ar=o-MeOC6H4, o-Me2NC6H4, o-(MeO)2C6H3.
with a reagent mixture of [Fe
A
G
N
C5H5)(CO)2}2].[28] After stirring for 8 h in CH2Cl2, the mono-
nuclear iron complexes 5b and 6b were separated from the
reaction mixture [Eq. (15)] by column chromatography and
were purified by recrystallization from an Et2O/CH2Cl2 mix-
ture. The white and bright-yellow crystalline materials 5b
and 6b were obtained in 57 and 36% yields, respectively.
The diphenylphosphonite derivative 5b crystallizes in the
acentric monoclinic space group C2 (no. 5) (a=2938.3(4),
on the electronic nature of the substituents R on the phos-
phorus atoms (Table 1), and increase in the series R=Ph,
OMe, OPh, C6F5, p-C5NF4, up to CF3. This trend can be in-
terpreted by using the classical s donation and p back-bond-
ing dualism in terms of an increasing p acidity of the phos-
phane ligands discussed. The trend observed is in accord-
ance with data of comparable nonchiral diphosphane com-
plexes (Table 1).
The highest CO valence
mode of the p-tetrafluoropyrid-
yl-substituted complex 8a is
shifted by 6 cmꢀ1 to higher
energy relative to the penta-
fluorophenyl derivative 7a,
which classifies the p-C5NF4
group as being the stronger
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9029

B. Hoge and P. Panne
center. Although the resonance of 5b represents a nonre-
solved singlet, the resonance of 6b exhibits the expected
ABspin-system splitting with a difference in chemical shift
2
of 0.9 ppm and a J
A
Figure 2. Thermal ellipsoid diagram of one of the two symmetry-inde-
pendent cationic iron complexes 5b as its tetrafluoroborate salt, and the
atom numbering scheme. The hydrogen atoms and BF4 counterion have
ꢀ
Figure 3. A) Experimental and B) calculated 31P{1H} NMR spectra of the
been omitted for clarity.
iron complex 6b.
b=1024.2(1), c=2512.5(3) pm, b=100.63(1)8). One of the
symmetry-independent cations is shown in Figure 2. Selected
bond lengths and angles of the two independent units are
listed in Table 2. A comparison with literature data reveals
that the phosphorus–iron distances of 214.7 to 215.8 pm, as
well as the Fe–CO distances of 176 and 177 pm, are within
the expected range.[29,30]
the experimental proton-decoupled 31P NMR spectrum (A)
of complex 6b, together with the calculated spectrum (B).
The CO stretching mode of the diphenylphosphonite com-
plex 5b is shifted to higher energy by 11 cmꢀ1 relative to the
dimethylphosphonite derivative 6b and describes the stron-
ger p acidity of the phenyl-substituted phosphane ligand,
which is in accordance with the trend observed for the com-
parable tetracarbonyl–molybdenum complexes 5a and 6a
(Table 1).
The carbonyl group in 5b and 6b should be removable by
UV irradiation, leading to reactive solvent adducts that rep-
resent potential chiral Lewis acids that should be capable of
catalyzing asymmetric Diels–Alder reactions.[31]
The 31P NMR resonances of the iron complexes 5b and
6b are deshielded by about 30 and 23 pm relative to the
free ligands 5 and 6, respectively. The formerly chemically
equivalent C2-symmetric phosphorus atoms of the free li-
gands become diastereomeric upon coordination to the iron
The reaction of the bis(pentafluorophenyl)phosphane de-
Table 2. Selected bond lengths [pm] and angles [8] of the two symmetry-
independent molecules of the iron complex 5b.
rivative 7 with the reagent combination of [Fe
A
G
ACHTREUNG
ꢀ
Fe1 P2
215.1(3)
215.7(3)
177(1)
211(1)
211(1)
212.9(8)
210.1(9)
208(1)
P3-Fe2-P4
P2-Fe1-P1
C1-Fe1-C6
C1-Fe1-C5
C1-Fe1-P2
93.6(1)
93.3(1)
92.6(4)
123.1(5)
90.3(3)
93.8(3)
127.1(7)
125.8(6)
clear chelate complex, such as 5b and 6b [Eq. (15)], but re-
sults in the coordination of one [FeCp(CO)2] unit at only
one phosphorus atom. This is supported by the observation
of two new 31P NMR resonances at 45.7 and ꢀ54.7 ppm for
the coordinated and free phosphorus atoms, respectively.
The intensity of the resonances for the mononuclear com-
plex decreases as the excess of the iron-reagent combination
increases, forming a nonchelate dinuclear iron complex 7b’
[Eq. (16)].
ꢀ
Fe1 P1
ꢀ
Fe1 C1
ꢀ
Fe1 C2
ꢀ
Fe1 C3
ꢀ
Fe1 C4
C1-Fe1-P1
ꢀ
Fe1 C5
C1C-O2C-P2
C1D-O2D-P2
105.6(4)
O1B-P1-C7
O1A-P1-C7
O1B-P1-Fe1
O1A-P1-Fe1
C7-P1-Fe1
ꢀ
Fe1 C6
ꢀ
P1 O1B160.9(7) -P1-O1AO1B
ꢀ
P1 O1A
162.0(7)
182(1)
159.1(7)
162.3(6)
180.4(9)
117(1)
97.0(4)
ꢀ
P1 C7
103.8(4)
116.2(3)
112.1(3)
120.0(4)
103.9(3)
97.7(4)
ꢀ
P2 O2C
ꢀ
P2 O2D
ꢀ
P2 C10
ꢀ
O1 C1
O2C-P2-O2D
O2C-P2-C10
ꢀ
O1A C1A
142(1)
ꢀ
O1B C1B141(1)
O2D-P2-C10
104.3(4)
ꢀ
O2 C11
143(1)
146(1)
143(1)
214.7(3)
215.8(3)
O2C-P2-Fe1
O2D-P2-Fe1
C10-P2-Fe1
C1A-O1A-P1
C1B-O1B-P1
117.5(3)
109.1(3)
122.2(3)
125.3(6)
122.8(6)
ꢀ
O2 C9
ꢀ
O2C C1C
ꢀ
Fe2 P3
ꢀ
Fe2 P4
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Functional Bidentate Diphenylphosphonite Derivatives
FULL PAPER
1H NMR (CDCl3, RT): d=1.3 (s, 6Ha), 1.6–1.9 (m, 4Hd), 3.5 (d, 2J-
As expected, both C2-symmetric complexes 7b’ and 8b’
exhibit a sharp 31P NMR resonance for the enantiotopic
phosphorus atoms at 48.3 and 52.5 ppm, respectively. These
resonances are deshielded by more than 100 ppm relative to
the free ligands. The dinuclear character of the complexes
7b’ and 8b’ is supported by characteristic ESI mass spectra
and the observation of two CO stretching modes of the
Fe(CO)2 moieties for both compounds. The CO stretching
modes of the bis(p-tetrafluoropyridyl)phosphane derivative
8b’ at 2077 and 2038 cmꢀ1 are shifted by 3 and 6 cmꢀ1, re-
spectively, to higher frequencies, relative to the bis(penta-
fluorophenyl)phosphane complex 7b’. The resulting classifi-
cation of the bis(p-tetrafluoropyridyl)phosphane derivative
as being the stronger p-acidic ligand is again in accordance
with a previously presented quantum-chemical model,[7] and
confirms the trend of the vibrational data of comparable
mononuclear tetracarbonyl–molybdenum derivatives 7a and
8a (Table 1).
A
N
13C{1H} NMR (CDCl3, RT): d=27.7 (s, Ca), 37.3 (dd, 1J
(C,P)=2 Hz; Cd), 54.3 (d, 2J(C,P)=12 Hz; Cf), 54.7 (d, 2J
Cf’), 78.1 (dd, 2J(C,P)=13 Hz, 3J(C,P)=7 Hz; Cc), 108.5 ppm (s, Cb);
ACHTREUNG
A
N
ACHTREUNG
A
ACHTREUNG
31P{1H} NMR (CDCl3, RT):d=183.8 ppm (s); IR (KBr pellet): n˜ =2985
(m), 2949 (m), 2901 (sh), 2853 (sh), 1462 (w), 1417 (sh), 1377 (m), 1302
(s), 1215 (vs), 1097 (sh), 1041 (vs), 904 (sh), 880 (s), 844 (w), 803 (m), 775
(m), 697 cmꢀ1 (m); MS (EI, 20 eV): m/z (%): 299 (13) [MꢀCH3]+, 221
(58) [MꢀP
U
G
1,4-Dideoxy-1,4-bis(diphenoxyphosphanyl)-2,3-O-isopropyliden-l-threi-
tol, 5: [Na([18]crown-6)]P(CN)2 (13.40 g, 36.19 mmol) and 1,4-dideoxy-
1,4-diiodo-2,3-O-isopropyliden-l-threitol, 2, (4.60 g, 12.04 mmol) were
dissolved in 30 mL of THF and stirred for 8 h at RT. After addition of
phenol (4.77 g, 50.69 mmol) and stirring for an additional hour at RT,
saltlike compounds were precipitated upon addition of hexane. The sepa-
rated solution was evaporated in vacuo and the residue was dissolved in
Experimental Section
Materials and apparatus: All chemicals were obtained from commercial
sources and were used without further purification. Literature methods
were used for the synthesis of 1,4-dideoxy-1,4-diiodo-2,3-O-isopropyli-
den-l-threitol, 2.[32] Standard high-vacuum techniques were employed
throughout all preparative procedures and nonvolatile compounds were
handled under a dry N2 atmosphere by using Schlenk techniques.
a concentrated solution of NaI in acetone. After evaporation, the residue
was extracted with hexane. Evaporation of the hexane yielded 5.23 g
(9.30 mmol, 77% with respect to 2) of 5 as a colorless oil. [a]2D0 =ꢀ308
(hexane, c=0.27).
Infrared spectra were recorded by using a Nicolet-5PC-FTIR spectrome-
ter and KBr pellets. Raman spectra were measured by using a Bruker
FRA-106/s spectrometer with a Nd:YAG laser operating at l=1064 nm.
The NMR spectra were recorded by using a Bruker Model AC200 spec-
trometer (31P, 81.01 MHz; 19F, 188.31 MHz; 1H, 200.13 MHz) with positive
shifts being downfield from the external standards (85% orthophosphoric
acid (31P), CCl3F (19F), and TMS (1H)). Higher-order NMR spectra were
calculated by using the program gNMR.[33] EI mass spectra were record-
ed by using a Finnigan MAT 95 spectrometer (20 eV) and ESI mass spec-
tra were recorded by using a Finnigan MAT 900 (70 eV) spectrometer.
Intensities were referenced to the most intense peak of a group. Isotope
patterns for comparison were calculated by using the program Isopro.[34]
Melting and visible decomposition points were determined by using a
HWS Mainz 2000 apparatus. The carbon, hydrogen, and nitrogen analy-
ses were carried out by using a HEKAtech Euro EA 3000 apparatus.
1H NMR (CDCl3, RT): d=1.4 (s, 6Ha), 1.9–2.4 (m, 4Hd), 4.1 (s, 2Hc),
6.8–7.3 ppm (m, 10Hgꢀi,g’–i’); 13C{1H} NMR (CDCl3, RT): d=27.0 (s, Ca),
37.8 (d, 1J
109.1 (s, Cb), 119.5 (d, 3J
123.4 (s, Ci,i’), 129.4 (s, Ch,h’), 155.2 (d, 2J
2J(C,P)=5 Hz; Cf’); 31P{1H} NMR (CDCl3, RT): d=178.3 ppm (s); IR
A
G
A
A
ACHTREUNG
AHCTREUNG
AHCTREUNG
(KBr pellet): n˜ =3263 (m), 1604 (sh), 1593 (vs), 1491 (vs), 1454 (sh), 1381
(m), 1373 (w), 1221 (vs), 1198 (vs), 1165 (s), 1109 (s), 1070 (m), 1037 (w),
1024 (m), 927 (w), 881 (s), 862 (vs), 758 (s), 715 (w), 692 cmꢀ1 (s); MS
(EI, 20 eV): m/z (%): 563 (1) [M]+, 547 (1) [MꢀCH3]+, 469 (100)
[MꢀOPh]+, 345 (38) [MꢀP
U
G
Syntheses
1,4-Dideoxy-1,4-bis(dimethoxyphosphanyl)-2,3-O-isopropyliden-l-threitol
(6): [Na([18]crown-6)]P(CN)2 (2.42 g, 6.54 mmol) and 1,4-dideoxy-1,4-
diiodo-2,3-O-isopropyliden-l-threitol, 2,(0.83 g, 2.17 mmol) were dis-
solved in 30 mL of THF and stirred for 8 h at RT. After addition of meth-
anol (0.56 g, 17.48 mmol) and stirring for an additional hour at RT, salt-
like compounds were precipitated upon addition of hexane. The filtrate
1,4-Dideoxy-1,4-bis[bis(pentafluorophenyl)phosphanyl]-2,3-O-isopropyli-
N
den-l-threitol (7): 1,4-Dideoxy-1,4-bis(diphenoxyphosphanyl)-2,3-O-iso-
propyliden-l-threitol, 5, (2.90 g, 5.16 mmol) dissolved in 30 mL of THF
was reacted with C6F5MgBr (7.69 g, 28.35 mmol) in 50 mL Et2O. After
stirring for 2 h at RT, the mixture was treated with hexane and washed
with water and an aqueous concentrated NH4Cl solution. The separated
was evaporated in vacuo and the residue was dissolved in a concentrated
solution of NaI in acetone. After evaporation, the residue was extracted
with hexane. Evaporation of the hexane yielded 0.54 g (1.72 mmol, 79%,
with respect to 2) of 6 as a colorless oil. [a]2D0 =ꢀ198 (hexane, c=0.12).
Chem. Eur. J. 2006, 12, 9025 – 9035
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
9031

B. Hoge and P. Panne
organic layer was evaporated and the brown oily residue was purified by
silica column chromatography (ethyl acetate/hexane 1:20). The resulting
white solid was recrystallized from methanol, yielding 4.00 g (4.66 mmol,
90% with respect to 5) of 7 as colorless crystals (m.p. 1138C). [a]D20
ꢀ128 (hexane, c=0.34).
=
1H NMR (CDCl3, RT): d=1.2 (s, 6Ha), 2.6–3.1 (m, 4Hd), 4.1 ppm (s,
1
2Hc); 13C{1H} NMR (CDCl3, RT): d=26.4 (s, Ca), 54.6 (d, J
A
Cd), 78.2 (dd, 2J
N
N
Cf,f’), 134—151 ppm (m, Cgꢀi,g’–i’); 19F NMR (CDCl3, RT): d=ꢀ129.9 (m,
Fg,g’), ꢀ149.4 (m, Fi), ꢀ149.7 (m, Fi’), ꢀ160.1 (m, Fh), ꢀ160.4 ppm (m, Fh’);
31P{1H} NMR (CDCl3, RT): d=ꢀ53.2 ppm (quin, 3J
G
39.2 (AXX’ spin system with A=13Cd, X=31P, J
ꢀ2 Hz, J
(X,X’)=10 Hz), 48.1 (m, Cf), 48.3 (m, Cf’), 76.7 (AXX’ spin
system with A=13Cc, X=31P, J
(A,X)=19 Hz, J (X,X’)=
(A,X’)=ꢀ3 Hz, J
9 Hz), 103.8 (s, Cb), 204.3 (t, 2J(C,P)=11 Hz; Cj), 209.2 ppm (dd, 2J-
(C,P)trans =34 Hz, 2J(C,P)cis =16 Hz; Ck); 31P{1H} NMR (CDCl3, RT): d=
A
G
AHCTREUNG
20 eV): m/z (%): 843 (6) [MꢀCH3]+, 493 (83) [MꢀP
U
U
N
[C16H6F10OP]+, 365 (17) [P(C6F5)2]+; elemental analysis calcd (%): C
C
AHCTREUNG
G
ACHTREUNG
43.38, H 1.41; found: C 43.33, H 1.50.
192.2 ppm (s); IR (KBr pellet): n˜ =2986 (vw), 2947 (vw), 2031 (s; CO),
1911 (vs), 1636 (w), 1458 (w), 1381 (w), 1244 (w), 1165 (vw), 1040 (m),
1015 (m), 889 (w), 820 (w), 781 (w), 710 (w), 604 (w), 589 (w), 572 cmꢀ1
(w); MS (EI, 20 eV): m/z (%): 522 (4) [M+ꢀCO], 494 (4) [M+ꢀ2CO],
1,4-Dideoxy-1,4-bis[bis(p-tetrafluoropyridyl)phosphanyl]-2,3-O-isopropy-
ACHTREUNG
liden-l-threitol (8): 1,4-Dideoxy-1,4-bis(diphenoxyphosphanyl)-2,3-O-iso-
propyliden-l-threitol, 5, (2.40 g, 4.27 mmol) dissolved in 30 mL of THF
was reacted with p-C5NF4MgBr (8.83 g, 34.72 mmol) in 50 mL Et2O.
After stirring for 2 h at RT, the reaction mixture was treated with hexane
and washed with water and an aqueous concentrated NH4Cl solution.
The separated organic layer was evaporated and the brown oily residue
was purified by silica column chromatography (ethyl acetate/hexane
1:20). The resulting white solid was recrystallized from hexane, giving a
466 (4) [M+ꢀ3CO], 438 (4) [M+ꢀ4CO], 300 (46) [Mo(CO)6
G
(28) [Mo(CO)3
N
N
A
N
4.63; found: C 35.05, H 4.39.
Tetracarbonyl{1,4-dideoxy-1,4-bis(diphenoxyphosphanyl)-2,3-O-isopropy-
liden-l-threitol-P,P’} molybdenum (5a): 1,4-Dideoxy-1,4-bis(diphenoxy-
phosphanyl)-2,3-O-isopropyliden-l-threitol, 5, (0.17 g, 0.30 mmol) and
[Mo(CO)4(nbd)] (0.09 g, 0.30 mmol) were dissolved in 10 mL of CH2Cl2
N
yield of 1.70 g (2.15 mmol, 50% with respect to 5) of 8 as slightly yellow
crystals (m.p. (decomp) 1038C). [a]2D0 =ꢀ108 (CH2Cl2, c=0.30).
1H NMR (CDCl3, RT): d=1.1 (s, 6Ha), 2.6–3.1 (m, 4Hd), 4.0 ppm (s,
and stirred for 3 h at RT. The filtered solution was evaporated in vacuo
and the residue was extracted with hexane. Evaporation of the hexane
yielded 0.12 g (0.16 mmol, 53%) of 5a as a white solid.
1
2Hc); 13C{1H} NMR (CDCl3, RT): d=25.4 (s, Ca), 53.7 (d, J
A
Cd), 77.3 (dd, 2J
C
G
1H NMR (CDCl3, RT): d=1.4 (s, 6Ha), 2.0–2.6 (m, 4Hd), 4.2 (s, 2Hc),
Fg), ꢀ89.4 (m, Fg’), ꢀ131.6 (m, Fh), ꢀ138.8 ppm (m, Fh’); 31P{1H} NMR
6.9–7.5 ppm (m, 10Hg–i,g’–i’); 13C{1H} NMR (CDCl3, RT): d=22.9 (s, Ca),
(CDCl3, RT): d=ꢀ49.9 ppm (quin, 3J
A
1
36.9 (d, J
G
(d, 3J
Ch’), 148.6 (d, 2J
2J(C,P)=11 Hz; Cj), 206.9 ppm (dd, 2J
ACHTREUNG
2926 (vw), 1655 (w), 1633 (m), 1472 (sh), 1451 (vs), 1399 (w), 1385 (w),
1259 (sh), 1237 (m), 1207 (w), 968 (w), 943 cmꢀ1 (m); MS (EI, 20 eV):
m/z (%): 775 (8) [MꢀCH3+], 715 (4) [C24H6F16N4P2+], 459 (33) [MꢀP-
A
(C5NF4)2+], 401 (100) [C14H6F8N2OP+]; elemental analysis calcd (%): C
Ck); 31P{1H} NMR (CDCl3, RT): d=190.4 ppm (s); IR (KBr pellet): n˜ =
2986 (vw), 2038 (s; CO), 1925 (vs), 1592 (m), 1488 (s), 1455 (w), 1381
(w), 1211 (m), 1188 (s), 1162 (m), 1053 (w), 1024 (w), 883 (s), 761 (m),
690 cmꢀ1 (m); MS (EI, 20 eV): m/z (%): 770 (17) [M]+, 742 (8)
[MꢀCO]+, 786 (96) [Mꢀ3CO]+, 758 (50) [Mꢀ4CO]+, 469 (8)
41.03, N 7.09, H 1.53; found: C 42.12, N 7.23, H 1.70.
Tetracarbonyl{1,4-dideoxy-1,4-bis(dimethoxyphosphanyl)-2,3-O-isopropy-
liden-l-threitol-P,P’}molybdenum (6a): 1,4-Dideoxy-1,4-bis(dimethoxy-
phosphanyl)-2,3-O-isopropyliden-l-threitol, 6, (0.30 g, 0.95 mmol) and
[Mo(CO)
A
[MꢀMo(CO)4P
N
N
and stirred for 3 h at RT. The filtered solution was evaporated in vacuo
and the residue was extracted with hexane. Evaporation of the hexane
yielded 0.13 g of a slightly yellow oil. The product 6a contained minor
mental analysis calcd (%): C 54.56, H 4.19; found: C 54.43, H 4.66.
Tetracarbonyl{1,4-dideoxy-1,4-bis[bis(pentafluorophenyl)phosphanyl]-
2,3-O-isopropyliden-l-threitol-P,P’} molybdenum (7a): 1,4-Dideoxy-1,4-
bis[bis(pentafluorophenyl)phosphanyl]-2,3-O-isopropyliden-l-threitol, 7,
(0.30 g, 0.35 mmol) and [Mo(CO)4(nbd)] (0.11 g, 0.37 mmol) were dis-
solved in 10 mL of CH2Cl2 and stirred for 3 h at RT. The filtered solution
AHCTREUNG
amounts of [Mo(CO)4(nbd)].
E
AHCTREUNG
1H NMR (CDCl3, RT): d=1.4 (s, 6Ha), 1.9–2.4 (m, 4Hd), 3.5 (s, 6Hf), 3.6
ACHTREUNG
(s, 6Hf’), 3.9 ppm (s, 2Hc); 13C{1H} NMR (CDCl3, RT): d=22.9 (s, Ca),
9032
www.chemeurj.org
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2006, 12, 9025 – 9035

Functional Bidentate Diphenylphosphonite Derivatives
FULL PAPER
AHCTREUNG
,
954 (4) [Mꢀ4CO]+, 842 (71) [MꢀMo(CO)4CH3]+, 782 (29)
[C28H4F20P2]+,
493
(46)
[MꢀMo(CO)4P
(C6F5)2]+,
435
(100)
[C16H6F10OP]+, 365 (17) [P(C6F5)2]+; elemental analysis calcd (%): C
U
37.02, H 0.91; found: C 37.20, H 0.97.
Attempted synthesis of tetracarbonyl{1,4-dideoxy-1,4-bis[bis(p-tetrafluo-
E
AHCTREUNG
AHCTREUNG
ACHTREUNG
AHCTREUNG
and the mixture was stirred for an additional 8 h. The reaction mixture
was evaporated in vacuo and the residue was extracted with hexane. The
residue of the evaporated hexane solution was investigated by infrared
and NMR spectroscopy. Resonances at 10.3 and 6.6 ppm in the 31P NMR
spectrum indicated the possible formation of a dinuclear [Mo(CO)5] com-
plex 8a’ and a mononuclear [Mo(CO)4] derivative 8a, respectively. The
highest CO infrared valence modes of these compounds were observed
at 2084 and 2047 cmꢀ1, respectively. A separation of these compounds by
silica gel column chromatography was not successful.
was evaporated in vacuo and the residue was extracted with hexane.
Evaporation of the hexane yielded 0.10 g (0.09 mmol, 26% with respect
to 7) of 7a as a white solid (m.p. (decomp) 1308C).
1H NMR (CDCl3, RT): d=1.3 (s, 6Ha), 3.6–3.9 (m, 4Hd), 2.7 ppm (m,
2Hc); 13C{1H} NMR (CDCl3, RT): d=26.5 (s, Ca), 34.5 (m, Cd), 78.4 (dd,
3
2J
A
G
151 (m, Cgꢀi,g’–i’), 206 ppm (t, J(C,P)=8 Hz; Cj,k); 19F NMR (CDCl3, RT):
2
d=ꢀ132.3 (m, Fg), ꢀ134.4 (m, Fg’), ꢀ148.7 (m, Fi), ꢀ152.4 (m, Fi’),
ꢀ161.4 (m, Fh), ꢀ162.6 ppm (m, Fh’); 31P{1H} NMR (CDCl3, RT): d=
ꢀ1.6 ppm (s); IR (KBr pellet): n˜ =3439 (w), 2990 (vw), 2870 (vw), 2082
(vw), 2041 (s; CO), 1952 (vs), 1935 (vs), 1918 (vs), 1641 (m), 1521 (s),
1473 (vs), 1385 (m), 1294 (w), 1245 (vw), 1144 (w), 1094 (s), 1064 (w),
979 (s), 886 (w), 607 (w), 580 cmꢀ1 (m); MS (EI, 20 eV): m/z (%): 1066
(1) [M]+, 1038 (1) [MꢀCO]+, 1010 (1) [Mꢀ2CO]+, 982 (1) [Mꢀ3CO]+,
954 (1) [Mꢀ4CO]+, 843 (38) [MꢀMo(CO)4CH3]+, 493 (46)
Carbonyl(h5-cyclopentadienyl){1,4-dideoxy-1,4-bis(dimethoxyphosphan-
yl)-2,3-O-isopropyliden-l-threitol-P,P’}iron(II)tetrafluoroborate (6b): 1,4-
Dideoxy-1,4-bis(dimethoxyphosphanyl)-2,3-O-isopropyliden-l-threitol,
6
(0.21 g, 0.67 mmol), [Fe [BF4] (0.18 g, 0.66 mmol), and [{Fe
A
N
ACHTREUNG
C5H5)(CO)2}2] (0.12 g, 0.34 mmol) were dissolved in 20 mL CH2Cl2 and
the mixture was stirred for 8 h at RT. The evaporated residue was puri-
fied by silica gel column chromatography: 1) ethyl acetate/hexane 1:20;
[MꢀMo(CO)4P
elemental analysis calcd (%): C 39.42, H 1.13; found: C 40.05, H 1.47.
m-{1,4-Dideoxy-1,4-bis[bis(pentafluorophenyl)phosphanyl]-2,3-O-isopro-
pyliden-l-threitol-1kP:2kP’}bis[pentacarbonylmolybdenum] (7a’):
A
N
ACHTREUNG
[Mo(CO)6] (2.00 g, 7.58 mmol) was dissolved in 100 mL of acetonitrile
and refluxed for 8 h. The reaction mixture was evaporated, suspended in
100 mL
of
hexane,
and
treated
with
1,4-dideoxy-1,4-bis-
2) CH2Cl2; 3) acetone. Evaporation of the acetone fraction and recrystal-
lization from CH2Cl2/Et2O yielded 0.13 g (0.24 mmol, 36% with respect
to 6) of 6b as a bright-yellow solid.
1H NMR (CDCl3, RT): d=1.4 (s, 6Ha,a’), 2.2–3.2 (m, 4Hd,d’), 3.6 (s,
6Hf,f’,f’’,f’’’), 4.1 (brs), 2Hc,c’), 5.1 ppm (brs, 5Hk); 13C{1H} NMR (CDCl3,
RT): d=23.1 (s, Ca,a’), 35.5 (m, Cd), 37.3 (m, Cd’), 50.4 (m, Cf,f’,f’’,f’’’), 73.1
(m, Cc), 73.2 (m, Cc’), 104.9 ppm (s, Cb); 19F NMR (CDCl3, RT): d=
ꢀ152.1 ppm (s, BF4); 31P{1H} NMR (CDCl3, RT): d=206.5 (ABspin
system, Pe), 207.4 ppm (ABspin system, 2J(Pe,Pe’)=86 Hz; Pe’); IR (KBr
G
pellet): n˜ =2122 (vw), 2986 (vw), 2954 (w), 1987 (s; CO), 1637 (vw), 1459
(w), 1375 (w), 1248 (m), 1165 (sh), 1083 (vs), 1014 (vs), 884 (m), 828 (m),
799 (m), 752 (m), 558 cmꢀ1 (m); ESI-MS (positive mode, MeOH/
CH2Cl2): m/z (%): 463 (100) [MꢀBF4]+; elemental analysis calcd (%): C
37.19, H 5.14; found: C 36.94, H 4.89.
Carbonyl(h5-cyclopentadienyl){1,4-dideoxy-1,4-bis(diphenoxyphosphan-
yl)-2,3-O-isopropyliden-l-threitol-P,P’}iron(II)tetrafluoroborate (5b): 1,4-
A
7
(0.14 g, 0.16 mmol). After 2 h heating under reflux the suspension was fil-
tered hot and the filtrate evaporated in vacuo yielding a yellow solid.
Dideoxy-1,4-bis(diphenoxyphosphanyl)-2,3-O-isopropyliden-l-threitol,
5
13C{1H} NMR (CDCl3, RT): d=25.9 (s, Ca), 34.2–34.5 (m, Cd), 70.6 (not
(0.38 g, 0.68 mmol), [Fe [BF4] (0.19 g, 0.70 mmol), and [{Fe
A
N
ACHTREUNG
assigned), 75.2 (not assigned), 78.0 (m, Cc), 110.6 (s, Cb), 109 (m, Cf,f’),
C5H5)(CO)2}2] (0.12 g, 0.34 mmol) were dissolved in 20 mL of CH2Cl2 and
stirred for 8 h at RT. The evaporated residue was purified under a nitro-
135–150 (m, Cgꢀi,g’–i’), 203.8 (d, 2J
Chem. Eur. J. 2006, 12, 9025 – 9035
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
9033

B. Hoge and P. Panne
(vw), 600 (w), 572 (m), 549 cmꢀ1 (m); ESI-MS (positive mode, MeOH/
CH2Cl2): m/z (%): 1299 (100) [MꢀBF4]+, 1243 (52) [MꢀBF4(CO)2]+,
1035 (96) [MꢀFeCp(CO)2BF4]+, 976 (17) [MꢀFeCp(CO)4BF4]+; elemen-
tal analysis calcd (%): C 39.00, H 1.60; found: C 38.71, H 1.53.
m-{1,4-Dideoxy-1,4-bis
pyliden-l-threitol-1kP:2kP’}bis[dicarbonyl(h5-cyclopentadienyl)iron]bis-
(tetrafluoroborate) (8b’): 1,4-Dideoxy-1,4-bis(p-tetrafluoropyridyl)-2,3-
O-isopropyliden-l-threitol, (0.30 g, 0.38 mmol), [Fe [BF4]
(h5-C5H5)2]
(0.31 g, 1.14 mmol), and [{Fe
(h5-C5H5)(CO)2}2] (0.20 g, 0.57 mmol) were
[bis(p-tetrafluoropyridyl)phosphanyl]-2,3-O-isopro-
AHCTREUNG
8
A
ACHTREUNG
AHCTREUNG
dissolved in 30 mL of CH2Cl2 and the mixture was stirred for 48 h at RT.
The evaporated residue was purified under a nitrogen atmosphere by
silica gel column chromatography: 1) ethyl acetate/hexane 1:20; 2)
CH2Cl2; 3) acetone. As the evaporated acetone fraction still contained
the free ligand 7, the crude product was dissolved in CH2Cl2 treated with
[Fe
A
G
N
(0.13 g, 0.37 mmol), and the mixture was stirred for one week at RT.
After an additional separation by silica gel column chromatography the
product (0.20 g) was contaminated with a BF4 salt, as indicated in the
19F NMR spectrum that exhibited a resonance for the BF4 moiety that
was too intense with respect to the intensities of the resonances for the
C6F5 groups. 19F NMR (CDCl3, RT): d=ꢀ87.0/ꢀ87.4 (ortho-F, rel. int.
8.0), ꢀ127.0 (meta-F, rel. int. 7.9), ꢀ148.3 ppm (BF4, rel. int. 55);
31P NMR (CDCl3, RT): d=52.5 ppm; IR (KBr pellet): n˜ =2977 (m), 2877
(m), 2077 (s; CO), 2038 (s; CO), 1636 (m), 1457 (vs), 1385 (w), 1239 (s),
1084 (vs), 946 (m), 575 cmꢀ1 (m); ESI-MS (positive mode, MeOH/
CH2Cl2): m/z (%): 967 (100) [MꢀFeCp(CO)2BF4]+, 911 (67) [MꢀFeCp-
gen atmosphere by silica gel column chromatography: 1) ethyl acetate/
hexane 1:20; 2) CH2Cl2; 3) acetone. Evaporation of the acetone fraction
and recrystallization from CH2Cl/Et2O yielded 0.31 g (0.39 mmol, 57%
with respect to 5) of 5b as a colorless solid (m.p. (decomp) 1808C).
1H NMR (CDCl3, RT): d=1.1 (s, 6Ha), 1.4 (s, 6Ha’), 2.4–4.3 (m, 6Hc,c’,d,d’),
4.8 (s, 5Hk), 7.3 ppm (m, 10Hgꢀi,g’–i’,g’’–i’’,g’’’–i’’’); 13C{1H} NMR (CDCl3, RT):
d=26.9 (s, Ca), 27.1 (s, Ca’), 40.4–43.5 (m, Cd,d’), 73.0–76.0 (s, Cc,c’), 86.0 (s,
Ck), 109.5 (s, Cb), 120.4 (s, Cg), 120.9 (s, Cg’), 121.3 (s, Cg’’), 121.5 (s, Cg’’’),
126.1–126.4 (m, Ci,i’,i’’,i’’’), 130.9–131.1 (m, Ch,h’,h’’,h’’’), 152.0 (m, Cf,f’,f’’,f’’’),
212.9 ppm (t, 2J(C,P)=32 Hz; Cj); 19F NMR (CDCl3, RT): d=
R
ꢀ151.7 ppm (s, BF4); 31P{1H} NMR (CDCl3, RT): d=207.9 ppm (s, Pe,e’);
IR (KBr pellet): n˜ =2984 (w), 2932 (w), 2066 (vw), 1998 (vs; CO), 1590
(s), 1487 (vs), 1456 (w), 1422 (vw), 1375 (m), 1189 (s), 1163 (s), 1883 (vs),
1058 (vs), 916 (vs), 900 (vs), 784 (m), 761 (s), 728 (w), 692 (m), 616 (w),
582 (m), 564 cmꢀ1 (m); ESI-MS (positive mode, MeOH/CH2Cl2): m/z
(%): 1003 (100) [M+FeCp(CO)3]+, 739 (46) [M+COꢀBF4]+, 711 (58)
[MꢀBF4]+, 683 (8) [MꢀBF4CO]+; elemental analysis calcd (%): C 56.67,
H 4.67; found: C 56.15, H 4.67.
(CO)4BF4]+, 572 (54) [Mꢀ
R
Single-crystal structure determination: Data collection for X-ray struc-
ture determination was performed by using a STOE IPDS II diffractome-
ter with graphite-monochromated MoKa radiation (71.073 pm). The data
were corrected for Lorentz and polarization effects. A numerical absorp-
tion correction based on crystal-shape optimization was applied for all
data (X-Shape 2.01, Crystal Optimisation for Numerical Absorption Cor-
rection (C) 2001 Stoe & Cie GmbH, Darmstadt). The programs used in
this work are the Stoe X-Area (X-Area 1.16, Stoe & Cie GmbH, Darm-
stadt, 2003), including X-RED and X-Shape for data reduction and nu-
merical absorption correction (X-RED32 1.03, Stoe Data Reduction Pro-
gram (C), 2002, Stoe & Cie GmbH, Darmstadt), and X-Step32 program
m-{1,4-Dideoxy-1,4-bis
pyliden-l-threitol-1kP:2kP’}bis[dicarbonyl(h5-cyclopentadienyl)iron]bis-
(tetrafluoroborate) (7b’): 1,4-Dideoxy-1,4-bis(pentafluorophenyl)-2,3-O-
isopropyliden-l-threitol, (0.27 g, 0.31 mmol), [Fe [BF4]
(h5-C5H5)2]
(0.22 g, 0.81 mmol), and [{Fe
(h5-C5H5)(CO)2}2] (0.14 g, 0.40 mmol) were
[bis(pentafluorophenyl)phosphanyl]-2,3-O-isopro-
ACHTREUNG
7
A
ACHTREUNG
AHCTREUNG
(X-STEP32 1.06f, 2000, Stoe
& Cie GmbH, Darmstadt), including
dissolved in 20 mL of CH2Cl2 and the mixture was stirred for 8 h at RT.
The evaporated residue was purified under a nitrogen atmosphere by
silica gel column chromatography: 1) hexane; 2) CH2Cl2; 3) CH2Cl2/ace-
tone 1:1. Evaporation of the CH2Cl2/acetone fraction and recrystalliza-
tion from CH2Cl2/Et2O yielded 0.14 g (0.10 mmol, 32% with respect to 7)
SHELXS-97 (G. M. Sheldrick, SHELXS-97, University of Gçttingen,
1998) and SHELXL-97 (G. M. Sheldrick, SHELXL-97, University of
Gçttingen, 1997) for structure solution and refinement. All hydrogen
atoms were placed in idealized positions and constrained to ride on the
coordinates of the previous atom. The last cycles of refinement included
atomic positions for all the atoms, anisotropic thermal parameters for all
the non-hydrogen atoms, and isotropic thermal parameters for all the hy-
drogen atoms. Intensity data for C37H37O7P2FeBF4 (798.27 gmolꢀ1) was
collected at 170 K; colorless transparent plate, monoclinic space group C2
(no. 5); a=2938.3(4) b=1024.2(1) c=2512.5(3) pm, b=100.63(1)8, V=
7.431 nm3, Z=8, 1calcd =1.427 gcmꢀ3, m
N
N
43613 reflections with 2.8<2q<54.78, 16381 independent reflections in
structure solution and refinement for 937 parameters, Flack x=0.03(3),
R1 [Iꢂ2s(I)]=0.077, wR2 (all data)=0.110, w=1/{s2(F02) + 0.0108(F02
+
2F2c)/3]2}.
CCDC 608264 contains the supplementary crystallographic data for this
paper (compound 6). These data can be obtained free of charge from
The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif.
of 7b’ as a colorless solid (m.p. (decomp) 1808C).
1H NMR (CDCl3, RT): d=1.2 (s, 6Ha), 3.3–3.9 (m, 4Hd), 4.4 (m, 2Hc),
5.7 ppm (s, 10Hk); 13C{1H} NMR (CDCl3, RT): d=26.8 (s, Ca), 35.5–36.0
(m, Cd), 78.1–78.4 (m, Cc), 90.6 (s, Ck), 112.7 (s, Cb), 109 (m, Cf,f’), 136–
150 (m, Cgꢀi,g’–i’), 209.2 ppm (pseudo-t, 2J(C,P)=20 Hz; Cj,j’); 19F NMR
A
Acknowledgements
(CDCl3, RT): d=ꢀ129.2 (m, 8Fg,g’), ꢀ145.4 (m, 2Fi), ꢀ146.8 (m, 2Fi’),
ꢀ158.2 (m, 4Fh), ꢀ158.4 (m, 4Fh’), ꢀ149.7 ppm (s, 2BF4); 31P{1H} NMR
(CDCl3, RT): d=48.3 ppm (s); IR (KBr pellet): n˜ =3122 (vw), 2989 (vw),
2939 (vw), 2074 (s; CO), 2032 (s; CO), 1645 (m), 1525 (s), 1476 (vs), 1429
(vw), 1388 (m), 1297 (w), 1240 (vw), 1097 (vs), 1060 (sh), 980 (s), 890
We want to thank Dr. K. Glinka and Dr. L. Ford for helpful discussions.
We are grateful to Prof. Dr. D. Naumann for his generous support and
the Deutsche Forschungsgemeinschaft is acknowledged for financial sup-
port.
9034
www.chemeurj.org
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2006, 12, 9025 – 9035

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Received: February 23, 2006
Revised: May 23, 2006
Published online: September 25, 2006
Chem. Eur. J. 2006, 12, 9025 – 9035
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
9035