Unusually large bite angle of a distally diphosphanylated calix[4]arene chelator

Article abstract of DOI:10.1002/ejic.201000595

5,17-Diphenylphosphanyl-11,23-bis(4-tolyl)-25,26,27,28-tetrapropoxycalix[4] arene (6), a semi-rigid, calixarene-based diphosphane in which the phosphorus atoms are separated by 12 chemical bonds, reacts with [Ni(η⁵- C₅H₅)(1,5-cyclooctadiene)]BF₄ or AgBF ₄ to afford the corresponding chelate complexes [Ni(η ⁵-C₅H₅)(6)]BF₄ and [Ag(6)]BF ₄ quantitatively. These complexes were both characterised by a single-crystal X-ray diffraction study. In the nickel complex the ligand shows a bite angle of 104.5°, which lies in the range expected for this kind of diphosphane with a large P???P separation. In the silver(I) complex the diphosphane displays a much larger bite angle of 138.8°, which was unexpected and reflects the flexilibilty of the calix[4]arene skeleton. Furthermore, in solution the silver complex shows dynamic behaviour. One of the observed motions corresponds to the silver atom switching reversibly from a linear to a bent AgP₂ cordination geometry. An upper-rim, distally diphosphanylated calix[4]arene readily forms a complex with AgBF₄. In the solid state the ligand displays an unexpectedly large bite angle of 138.8°, which reflects the flexibility of the calixarene skeleton. In solution the silver atom moves rapidly between two positions lying on either side of the calixarene axis.

Full text of DOI:10.1002/ejic.201000595

FULL PAPER
DOI: 10.1002/ejic.201000595
Unusually Large Bite Angle of a Distally Diphosphanylated Calix[4]arene
Chelator
Soheila Sameni,[a] Catherine Jeunesse,*[a] Mouhamad Awada,[a] Dominique Matt,*[a] and
Richard Welter[b]
Keywords: Calixarenes / Diphosphane / Nickel / Silver / Chelates / Strained ligands
5,17-Diphenylphosphanyl-11,23-bis(4-tolyl)-25,26,27,28-tetra- expected for this kind of diphosphane with a large P···P sepa-
propoxycalix[4]arene (6), a semi-rigid, calixarene-based di-
phosphane in which the phosphorus atoms are separated by
12 chemical bonds, reacts with [Ni(η5-C5H5)(1,5-cycloocta-
diene)]BF4 or AgBF4 to afford the corresponding chelate
complexes [Ni(η5-C5H5)(6)]BF4 and [Ag(6)]BF4 quantita-
tively. These complexes were both characterised by a single-
crystal X-ray diffraction study. In the nickel complex the li-
gand shows a bite angle of 104.5°, which lies in the range
ration. In the silver(I) complex the diphosphane displays a
much larger bite angle of 138.8°, which was unexpected and
reflects the flexilibilty of the calix[4]arene skeleton. Further-
more, in solution the silver complex shows dynamic behav-
iour. One of the observed motions corresponds to the silver
atom switching reversibly from a linear to a bent AgP2
cordination geometry.
we have investigated the coordination behaviour of 6
towards Ag+. Silver(I) was chosen for its ability to readily
form bent as well as linear arrangements when coordinated
to two phosphanes, i.e., to potentially accept chelating li-
gands with large bite angles. Calix[4]arene backbones con-
stitute semi-rigid platforms ideally suited for the synthesis
of podands with convergent ligand arms.[24–26] Several re-
cent studies have shown how the presence of a cavity in
these podants may drastically influence the coordinative
and catalytic ligand properties.[27–30]
Introduction
The bite angle and flexibility of diphosphane ligands are
important parameters, especially when considering their use
in homogeneous catalysis.[1–14] In recent studies we have in-
vestigated the coordination of several calix[4]arenes bearing
two phosphanyl groups on the distal positions, C5 and C17,
of the calixarene backbone.[15,16] We found that with NiII
and PdII these ligands (CALDIPs) resulted in cis-chelate
complexes in which the P–M–P angles were significantly
larger than 90°. These complexes were found to operate as
remarkably efficient catalysts in carbon–carbon coupling
reactions.[17–22] Their high reactivity was attributed to the
relatively large ligand bite angle (100–110°), which may fav-
our a reductive elimination step in the catalytic cycle
through steric effects involving the phosphorus substituents.
A factor likely to enhance this effect is the fanning motion
of the P–M–P plane in solution. These dynamics are char-
acterised by a periodic increase of the P–M–P angle
(Scheme 1).[16,23] For cis-[MX2(CALDIP)] complexes (M =
NiII, PdII, PtII), the highest bite angle observed to date in
the solid state was 110°,[19] this value possibly corresponds
to a minimum in solution. Pursuing our efforts to define
the limits of the flexibility of CALDIPs, and in particular to
examine whether bite angles significantly larger than 110°
remain compatible with chelation in this class of ligands,
Scheme 1. Typical dynamics of CALDIP complexes.
[a] Laboratoire de Chimie Inorganique et Catalyse, Université de
Strasbourg, Institut de Chimie UMR 7177 CNRS,
1 rue Blaise Pascal, 67008 Strasbourg cedex, France
[b] Laboratoire DECOMET, Université de Strasbourg, Institut de
Chimie UMR 7177 CNRS,
Results and Discussion
The ligand 6 used for this study was prepared in five
steps shown in Scheme 2. The synthesis began with a selec-
tive distal dilithiation of tetrabromocalixarene (1) with
4 rue Blaise Pascal, 67008 Strasbourg cedex, France
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Scheme 2. Synthesis of diphosphane 6.
nBuLi.[31] Quenching with B(OMe)3 followed by treatment
with HCl gave the diboronic acid 2, which was not isolated.
Compound 2 was directly converted into the corresponding
1,3-propanediol ester 3 (yield 88%). Suzuki–Miyaura cou-
pling of 3 with p-iodotoluene in the presence of Ag2CO3
and Pd(PPh3)4 afforded the expanded calixarene 4 in 93%
isolated yield. Phosphorus was then introduced through a
nickel-catalysed Arbuzov reaction using Ph2POEt.[15] The
bis(phosphane oxide) 5 obtained was finally reduced with
PhSiH3 giving the diphosphane 6 quantitatively. The 31P
NMR spectrum of 6 shows a peak at –6.4 ppm which is
in keeping with the formation of a triarylphosphane (cf.
–4.5 ppm for PPh3). The 1H NMR spectrum displays a con-
ventional AB pattern for the four methylenic ArCH2Ar
groups, with an AB separation of 1.27 ppm, in accord with
a calixarene backbone in the cone conformation.[32]
Figure 1. A view of the molecular structure of [Ni(η5-C5H5)(6)]BF4
(7). The complex crystallises with one molecule of chloroform
(omitted for clarity). Bond lengths [Å] and angle [°]: P–Ni 2.184(2);
PЈ–Ni 2.214(2); P–Ni–PЈ 104.6(1). Only the hydrogen atoms of the
Cp ring are shown.
Reaction of 6 with AgBF4 gave complex 8 (Figure 2) as
Reaction of 6 with [Ni(η5-C5H5)(1,5-cyclooctadiene)]BF4 the sole product. As for 7, all room temperature NMR spec-
gave complex 7 (Figure 1) in high yield (Scheme 3). The troscopic data were in accord with C2v symmetry. A single-
chelating behaviour of the ligand was confirmed by an X- crystal X-ray diffraction study revealed that in the solid
ray diffraction study (Figure 2). In the solid state, the metal state the AgP2 moiety adopts a bent form with a P–Ag–P
atom is oriented towards one side of the cavity. The dihe- angle of 138.8°. The metal atom lies “higher” above the
dral angle between the P–Ni–P plane and the calixarene cavity than that in 7, the P–Ag–P plane forming an angle
reference plane, defined as the average plane containing the of 47.4° with the calix reference plane (cf. 19.2° in 7). An
four ArCH2 carbon atoms, is 19.2°. The value of the P–Ni– interaction between the silver atom and the neighbouring
P angle, 104.6°, is close to that found in two related [Ni(η5- BF4 moiety can be ruled out, as the closest F atom lies at
C5H5)(CALDIP)]BF4 complexes.[17,22] The room tempera- a distance of 2.86 Å from the metal. We note that short
1
ture H and 31P NMR spectra are in accord with C2v sym- F···HC(aromatic) contacts can be seen for two fluorine
metry, which actually reflects a fast fanning motion of the atoms (2.39 and 2.53 Å). A survey of the CCDC revealed
P–Ni–P plane about the P···P axis similar to that previously that in the vast majority of complexes of general formula
reported for several [MX2(CALDIP)] (X = halide) and [Ag(phosphane)2]BF4 the P–Ag–P angle lies between 150°–
[M(η5-C5H5)(CALDIP)] complexes.[16,17] In this process the 180°, regardless of whether an interaction between the silver
nickel atom moves between two positions on either side of atom and the BF4 unit exists or not.[33–36] The above bite
the calixarene axis.
angle of “only” 138.8° is therefore likely to reflect the strain
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Calix[4]arene Chelator with a Large Bite Angle
Scheme 3. Synthesis of complexes 7 and 8.
the silver atom (Figure 2, bottom). Our previous studies of
the solution dynamics of [MX2(CALDIP)] complexes have
led to the conclusion that during the fanning motion of
the P–M–P plane, the ligand bite angle should periodically
increase and thus transiently push two phosphorus substit-
uents towards the two X ligands. The present study not only
confirms that bite angles much larger than 110° are access-
ible for CALDIPs, but also that in the corresponding com-
plexes a virtual metal embrace takes place. This phenome-
non should, of course, strongly favor a reductive elimi-
nation step in a catalytic C–C bond formation reaction.
The 31P NMR (121 MHz) and 1H NMR (300 MHz)
room temperature spectra of 8 (Figure 3) show an apparent
C2v symmetry of the complex, which is inconsistent with
the solid-state structure. These findings taken together with
the crystallographic study imply that in solution the silver
atom moves rapidly from one side of the calixarene axis to
the other, the position of the metal ion seen in the solid
Figure 2. Two views of the molecular structure of the silver com-
plex 8. The CPK model (right; BF4 anion omitted), showing P-aryl
rings in yellow, illustrates the steric crowding trans to the metal–
phosphorus bonds. Important bond lengths [Å] and angle [°]: Ag–
P1 2.4260(12); Ag–P2 2.4297(13); P1–Ag–P2 138.76(4).
within the calix backbone, which prevents the ligand from
reaching a larger bite angle. This strain becomes apparent
in the markedly unsymmetrical orientation of the two phen-
oxy rings bearing the tolyl groups (the dihedral angles of
the latter with the calixarene reference plane are 25° and
44°). Note that strained diphosphanes able to create bite
angles near 140° are quite rare, a recently reported ligand
for which such a value was found is EtXantphos.[37]
A further interesting aspect of this structure concerns the
bending of the two phenyl rings towards the metal centre,
Figure 3. Room temperature 31P NMR (121 MHz, CDCl3) and 1H
thereby resulting in a sterically crowded environment about NMR (300 MHz, CDCl3) spectra of 8.
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S. Sameni, C. Jeunesse, M. Awada, D. Matt, R. Welter
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Scheme 4. Proposed dynamics of the cationic complex 8. The dotted lines (red) indicate the trajectory of the silver ion in each type of
movement.
state corresponds to its maximal separation from the ca- frozen out at that temperature. As the J(P107,Ag) coupling
lixarene axis. On lowering the temperature, the 31P NMR constant (see Exp. Section) is smaller in the minor species
(202 MHz) spectrum first broadens (Figure 4), then co- A seen at low temperatures, we tentatively assign a bent
alesces and finally splits into two AX patterns (X = 107Ag/ structure to it.[36,38] Overall, the fluxional behaviour of the
109Ag) of relative intensity 1:4. The presence of two equili- calixarene silver complex 8 contrasts with that previously
brating species (denoted A and B in the 31P NMR spec- seen in PdII and PtII complexes containing similar diphos-
trum, Figure 4) was further confirmed by a variable tem- phanes, in which only one type of displacement was de-
1
perature H NMR study measured over the same tempera- tected.[16,17,23] This simply reflects the relatively easy change
ture range (–65 °C to +20 °C). Two concommitant phenom- in coordination geometry from linear to bent of silver(I).
ena may be considered to account for the observed spectra: Fluxional silver(I) complexes in which the metal ion
a) a rapid fanning motion of the P–Ag–P plane about the switches in an analogous manner between two coordination
P···P axis, displacing the silver atom along an arc, as pre- geometries have recently been shown to occur in molecular
viously observed for other metal ions in [MX2(CALDIP)] rotors.[39]
complexes (Scheme 4, a);[16,23] b) a switch from a bent to a
linear coordination mode of the silver atom (Scheme 4, b).
1
Conclusions
Interestingly, the H NMR spectrum (500 MHz) measured
at –65 °C revealed that the two species in equilibrium have
C2v symmetry (only one ArCH2Ar AB pattern is seen), an
observation which implies that the fanning motion is not
From previous studies[16,17,19,22,23] it is apparent that
CALDIPs preferentially behave as chelating ligands with a
bite angle lying in the range 100°–110° (in square planar or
tetrahedral complexes), although an authentic trans chelat-
ing binding mode has also been reported.[15] This study
shows, for the first time, that despite the rigidity of CALD-
IPs, the calixarene skeleton remains compatible with bite
angles near 140°. Overall, within the family of chelators
with wide bite angles, CALDIPs constitute rare exam-
ples[6,40] of diphosphanes giving access to bite angles not
only lying at both ends of the range 100–180°, but also in
the middle. Furthermore, it should be emphasised that our
findings confirm that in CALDIP chelate complexes char-
acterised by a P–M–P angle significantly larger than 110°,
the steric pressure exerted by the PPh substituents on the
first coordination sphere is drastically enhanced with re-
spect to that seen in the resting state. In our previously re-
ported C–C bond forming catalysts based on such ligands,
all resulting in fast reaction rates, we have proposed that the
P–M–P angle undergoes a periodic increase in the catalytic
intermediates, which consequently favours the coupling
step. This study clearly shows that if angles near 140° are
reached during these dynamics, this would then signifi-
cantly contribute to the high reaction rates observed.
Figure 4. Variable temperature 31P NMR study (202 MHz,
CD2Cl2) of 8 showing the appearance of two species at low tem-
perature. The peaks arising from the two equilibrating species are
labelled A and B.
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Calix[4]arene Chelator with a Large Bite Angle
ArCH2Ar], 3.97 (pseudo t, 3J = 8.2 Hz, 4 H, OCH2), 3.78 (m, 4 H,
OCH2), 2.37 (s, 6 H, C6H4CH3), 2.03–1.86 (m, 8 H, OCH2CH2),
Experimental Section
3
3
General Procedures: All commercial reagents were used as supplied.
The syntheses were performed in Schlenk-type flasks under dry
nitrogen. Solvents were dried by conventional methods and distilled
immediately prior to use. CDCl3 was passed through an alumina
column (5 cm length) and stored under nitrogen over molecular
sieves (4 Å). Routine 1H, 13C{1H} and 31P{1H} NMR spectra were
recorded with FT Bruker AVANCE 300 (1H: 300.1 MHz, 13C:
75.5 MHz, 31P: NMR 121.5 MHz) and AVANCE 500 (1H: NMR
500.1 MHz, 13C: 125.8 MHz) instruments at 25 °C. 1H NMR spec-
troscopic data were referenced to residual CHCl3 (δ = 7.26 ppm)
or CH2Cl2 (δ = 5.34 ppm). 13C NMR chemical shifts are reported
relative to CDCl3 (δ = 77.0 ppm), and the 31P NMR spectroscopic
data are given relative to external H3PO4. Mass spectra were re-
corded either with a Bruker MicroTOF spectrometer (ESI-TOF)
using CH2Cl2 as solvent, or with a Bruker MaldiTOF spectrometer
(MALDI-TOF) using α-cyano-4-hydroxycinnamic acid as matrix.
Elemental analyses were performed by the Service de Microanalyse,
Institut de Chimie (CNRS), Strasbourg. Melting points were deter-
1.06 (t, J = 7.4 Hz, 3 H, OCH2CH2CH3), 0.95 (t, J = 7.4 Hz, 3
H, OCH2CH2CH3) ppm. 13C{1H}NMR (CDCl3): δ = 156.59 and
155.16 (2s, Cq-O), 138.05–126.60 (arom. C atoms), 115.23 (s, Cq-
Br), 77.26 and 76.98 (2s, OCH2CH2CH3), 31.26 (s, ArCH2Ar),
23.49 and 23.22 (2s, OCH2CH2CH3), 21.24 (s, C6H4CH3), 10.68
and 10.17 (2s, OCH2CH2CH3) ppm. C54H58Br2O4 (Mr = 930.84):
calcd. C 69.68, H 6.28; found C 69.70, H 6.29.
5,17-Diphenylphosphanyl-11,23-bis(4-tolyl)-25,26,27,28-tetraprop-
oxycalix[4]arene (5): A suspension of 4 (2.00 g, 2.15 mmol) and an-
hydrous NiBr2 (0.28 g, 1.29 mmol) in PhCN (20 mL) was heated at
180 °C for 1 h. After addition of Ph2POEt (2.8 mL, 12.9 mmol) at
180 °C the reaction mixture was refluxed for a further 1 h. The
solvent was evaporated to dryness. The residue was taken up in
toluene (20 mL) and washed with NH3/H2O (5%, 4ϫ50 mL) and
H2O (2ϫ50 mL). The organic layer was separated and dried with
MgSO4. The solvent was evaporated to dryness and the product
was purified by column chromatography using acetone/cyclohexane
(30:70, v/v). Calixarene 5 was obtained as a white solid [Rf (SiO2,
acetone/cyclohexane, 20:80, v/v) = 0.16]; yield 1.60 g, 63%, m.p. Ͼ
250 °C, 1H NMR (CDCl3): δ = 7.70–7.63, 7.53–7.46 and 7.34–7.27
(20 H, PPh2), 7.50 (s, 4 H, m-H of OArP), 6.69 and 6.53 [AAЈBBЈ
spin system, 3J(AB) = 7.8; 4J(AAЈ) and 4J(BBЈ) Ͻ 1 Hz, 8 H,
OArC6H4Me, ], 6.34 (s, 4 H, m-H of OArC6H4Me), 4.49 and 3.19
[AB spin system, 2J(AB) = 13.2 Hz, 8 H, ArCH2Ar, ], 4.17 (pseudo
t, 3J = 8.2 Hz, 4 H, OCH2), 3.65 (t, 3J = 7.0 Hz, 4 H, OCH2), 2.33
(s, 6 H, C6H4CH3), 2.09–1.97 (m, 4 H, OCH2CH2CH3), 1.93–1.81
( m , 4 H , O C H 2 C H 2 C H 3 ) , 1 . 0 7 ( t , 3 J = 7 . 5 H z , 6 H ,
OCH2CH2CH3), 0.92 (t, 3J = 7.5 Hz, 6 H, OCH2CH2CH3) ppm.
13C{1H} NMR (CDCl3): δ = 161.32 and 154.72 (2s, arom. Cq-O),
137.91–124.28 (arom. C atoms), 77.50 and 76.82 (2s, OCH2), 31.17
(s, ArCH2Ar), 23.65 and 23.24 (2s, CH2CH3), 21.28 (s, C6H4CH3),
10.90 and 9.95 (2s, OCH2CH2CH3) ppm. 31P{1H} NMR (CDCl3):
δ = 29.6 (s, PPh2) ppm. C78H78O6P2·0.5CH2Cl2 (Mr = 1172.50 +
42.46): calcd. C 77.54, H 6.55; found C 77.57, H 6.61.
mined with
a Büchi 535 capillary melting point apparatus.
5,7,11,17-Tetrabromo-25,26,27,28-tetrapropoxycalix[4]arene (1)[31]
[41]
and [(η5-C5H5)Ni(COD)]BF4 were prepared according to litera-
ture procedures.
5,17-Dibromo-11,23-(1,3,2-dioxaborinanyl)-25,26,27,28-tetraprop-
oxycalix[4]arene (3): To a cold (–78 °C) solution of 1 (10.00 g,
11.01 mmol) in THF (350 mL) was added a 1.6  solution of n-
BuLi/hexane (14.1 mL, 22.6 mmol). After stirring for 15 min,
B(OMe)3 (4.9 mL, 44.0 mmol) was added rapidly. The solution was
stirred overnight at room temperature and then poured into a cold
HCl solution (3 , 500 mL, 0 °C). The product was extracted into
CHCl3 (2ϫ400 mL). The organic phase was washed with water
(2ϫ500 mL), dried with MgSO4, and the solvent was removed.
The crude boronic acid 2 obtained was introduced into a Dean–
Stark apparatus containing toluene (350 mL) and 1,3-propanediol
(3.0 mL, 41.3 mmol). After elimination of water (heating for ca.
1 h), the solvent was removed. The solid residue was recrystallised
from CHCl3/n-heptane to afford a white solid (8.89 g, 88%). Mp
Ͼ 250 °C. 1H NMR (CDCl3): δ = 7.54 (s, 4 H, m-H of OArB), 6.30
5,17-Diphenylphosphanyl-11,23-bis(4-tolyl)-25,26,27,28-tetraprop-
oxycalix[4]arene (6): A solution of 5 (1.20 mg, 1.02 mmol) and
PhSiH3 (1.0 mL, 8.18 mmol) in toluene (10 mL) was heated to re-
flux for 2 d. The solvent was evaporated to dryness and the residue
was taken up in CH2Cl2. Addition of MeOH afforded pure 6 as a
2
(s, 4 H, m-H of OArBr), 4.37 and 3.15 [AB spin system, J(AB) =
13.4 Hz, 8 H, ArCH2Ar], 4.22 (t, J = 5.4 Hz, 8 H, BOCH2CH2),
3
4.05 (pseudo t, 3J = 8.2 Hz, 4 H, OCH2CH2CH3), 3.63 (t, 3J =
6.8 Hz, 4 H, OCH2CH2CH3), 2.12 (quint., 3J = 5.2 Hz, 4 H,
BOCH2CH2), 1.98–1.80 (two overlapping m, 8 H, OCH2CH2CH3),
1.09 (t, 3J = 7.4 Hz, 3 H, CH3), 0.84 (t, 3J = 7.5 Hz, 3 H, CH3)
ppm. 13C{1H}NMR (CDCl3): δ = 160.28 and 154.41 (2s, Cq-O),
135.59 and 134.99 (arom. C atoms), 130.34 (s, Cq-B), 115.32 (s, Cq-
Br), 77.33 and 76.56 (2s, OCH2CH2CH3), 62.14 (s, BOCH2CH2),
31.03 (s, ArCH2Ar), 27.61 (s, BOCH2CH2), 23.59 and 23.00 (2s,
OCH2CH2CH3), 10.90 and 9.90 (2s, CH3) ppm. C46H56B2Br2O8
(Mr = 918.36): calcd. C 60.16, H 6.15; found C 60.25, H 6.30.
1
white powder; yield 1.17 g, 100%, m.p. 219.5–220.5 °C. H NMR
(CDCl3): δ = 7.35–7.26 and 7.20–7.13 (24 H, PPh2 and m-H of
3
4
OArP), 6.74 and 6.62 [AAЈBBЈ spin system, J(AB) = 7.8; J(AAЈ)
and 4J(BBЈ) Ͻ 1 Hz, 8 H, OArC6H4Me], 6.39 (s, 4 H, m-H of
OArC6H4Me), 4.47 and 3.12 [AB spin system, 2J(AB) = 13.1 Hz, 8
3
H, ArCH2Ar], 4.13 (pseudo t, 3J = 8.1 Hz, 4 H, OCH2), 3.65 (t, J
= 6.9 Hz, 4 H, OCH2), 2.34 (s, 6 H, C6H4CH3), 2.12–1.99 (m, 4 H,
3
OCH2CH2CH3), 1.94–1.82 (m, 4 H, OCH2CH2CH3), 1.08 (t, J =
7.5 Hz, 6 H, OCH2 CH2 CH3 ), 0.93 (t, 3 J = 7.5 Hz, 6 H,
OCH2CH2CH3) ppm. 13C{1H} NMR (CDCl3): δ = 158.85 and
154.77 (2s, arom. Cq-O), 138.48–126.06 (arom. C atoms), 77.37 and
76.68 (2s, OCH2CH2CH3), 31.28 (s, ArCH2Ar), 23.65 and 23.23
(2s, OCH2CH2CH3), 21.29 (s, C6H4CH3), 10.94 and 9.97 (2s,
OCH2CH2CH3) ppm. 31P{1H} NMR (CDCl3): δ = –6.4 (s, PPh2)
ppm. C78H78O4P2·CH3OH (Mr = 1141.40 + 32.04): calcd. C 80.86,
H 7.04; found C 80.93, H 7.12.
5,17-Dibromo-11,23-bis(p-tolyl)-25,26,27,28-tetrapropoxycalix[4]-
arene (4): A mixture of 3 (4.00 g, 4.36 mmol), 4-iodotoluene (4.75 g,
21.78 mmol), Ag2CO3 (4.80 g, 17.42 mmol) and Pd(PPh3)4 (1.50 g,
0.44 mmol) was heated in refluxing THF (100 mL) for 24 h. The
solution was filtered through Celite and the solvents evaporated to
dryness. The residue was chromatographed on silica gel using
CH2Cl2/cyclohexane (15:85, v/v), yielding 4 as a white solid [Rf
(SiO2, CH2Cl2/cyclohexane, 15:85, v/v) = 0.2]; yield 3.77 g, 93%;
m.p. Ͼ250 °C. 1H NMR (CDCl3): δ = 7.30 and 7.11 [C6H4Me,
cis-P,PЈ-(η5-Cyclopentadienyl)-{5,11-diphenylphosphanyl-17,23-
bis(4-tolyl)-25,26,27,28-tetrapropoxycalix[4]arene}nickel(II) Tetra-
fluoroborate (7): To a solution of 6 (0.082 g, 0.072 mmol) in CH2Cl2
(15 mL) was added a solution of [(η5-C5H5)Ni(COD)]BF4 (0.025 g,
0.079 mmol) in CH2Cl2 (3 mL). After stirring for 12 h, the solution
4
4
3J(AB) = 8.2 and J(AAЈ) ≈ J(BBЈ) ≈ 2.0 Hz, 8 H, AAЈBBЈ spin
system], 7.10 (s, 4 H, m-H of OArC6H4Me), 6.62 (s, 4 H, m-H of
OArBr), 4.46 and 3.19 [AB spin system, 2J(AB) = 13.2 Hz, 4 H,
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S. Sameni, C. Jeunesse, M. Awada, D. Matt, R. Welter
FULL PAPER
was concentrated to ca. 2 mL. Addition of Et2O afforded 7 as an
orange powder; yield 0.070 g, 72%, m.p. 230 °C (dec.). Crystals
suitable for X-ray diffraction were obtained by cooling a CHCl3
mounted on a Nonius Kappa CCD. Data collection with Mo-Kα
radiation (λ = 0.71073 Å) was carried out at 173 K using the Non-
ius collect suite.[42] 46435 reflections were collected (1.5 Ͻ θ Ͻ
27.5°), 17106 being found to be unique (merging R = 0.082). The
structure was solved with SIR-97.[43] Final results: R1 = 0.0814,
wR2 = 0.2345, goodness of fit = 1.063, 758 parameters, residual
1
solution of the complex. H NMR (CDCl3): δ = 7.28–7.20 (28 H,
PPh2 and C6H4Me), 6.92, 6.78 and 6.53 (broad signals, 16 H, m-H
of OAr), 4.83 (s, 5 H, C5H5), 4.60 and 3.30 [AB spin system, 2J(AB)
= 14.2 Hz, 8 H, ArCH2Ar], 4.08 (br. t, 3J = 8.1 Hz, 4 H, electron density: min./max. = –1.174/1.216 eÅ–3. Some important
OCH2CH2CH3), 3.82 (t, 3J = 6.6 Hz, 4 H, OCH2CH2CH3), 2.28
bond lengths and angles are given in Figure 2.
3
(s, 6 H, C6H4CH3), 1.99–1.83 (m, 8 H, OCH2CH2CH3), 1.14 (t, J
CCDC-771492 (for 7) and -771518 (for 8) contain the supplemen-
tary crystallographic data for this paper. These data can be ob-
tained free of charge from The Cambridge Crystallographic Data
Centre via www.ccdc.cam.ac.uk/data_request/cif.
= 7.2 Hz, 6 H, OCH2CH2CH3), 0.83 (t, 3J = 7.3 Hz, 6 H,
OCH2CH2CH3) ppm. 13C{1H} NMR (CDCl3): δ = 158.84 and
157.46 (2s, arom. Cq-O), 137.33–126.88 (arom. CЈs), 77.49 and
76.63 (2s, OCH2CH2CH3), 31.68 (s, ArCH2Ar), 23.64 and 22.70
(2s, OCH2CH2CH3), 21.09 (s, C6H4CH3), 10.91 and 9.65 (2s,
OCH2CH2CH3) ppm. 31P NMR (CDCl3): δ = 31.3 (s broad, PPh2)
ppm. C83H83BF4NiO4P2·CHCl3 (Mr = 1351.99 + 119.38): calcd.
C 68.57, H 5.75; found C 68.31, H 6.03.
Acknowledgments
This work was supported by the French Agence Nationale de la
Recherche (ANR MATCALCAT Program).
{5,11-Diphenylphosphanyl-17,23-bis(4-tolyl)-25,26,27,28-
tetrapropoxycalix[4]arene}silver(I) Tetrafluoroborate (8): To a solu-
tion of AgBF4 (0.016 g, 0.081 mmol) in THF (1 mL) was added a
solution of 6 (0.093 g, 0.081 mmol) in CH2Cl2 (15 mL). After stir-
ring for 1 h, the solution was concentrated to ca. 2 mL. Addition
of pentane afforded 8 as a white powder; yield 0.082 g, 75%, m.p.
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238–239 °C (dec.). H NMR (CDCl3, 25 °C, 300 MHz): δ = 7.49–
7.20 (28 H, PPh2 and C6H4Me), 7.04 (s, 4 H, m-H of OArC6H4Me),
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¯
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Received: May 28, 2010
Published Online: September 23, 2010
Eur. J. Inorg. Chem. 2010, 4917–4923
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
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