Synthesis and characterization of bismuth(III) and antimony(III) calixarene complexes

Article abstract of DOI:10.1021/ic801445m

A series of calixarene bismuth and antimony complexes have been fully characterized by NMR, X-ray, IR, UV/vis, and elemental analysis. The reactions of SbCl₃ with the monosodium salt of p-tert-butylcalix[4]arene (Bu^tC4), Bu^tC4·Na, and the tetralithium salt of para-tert-butylcalix[4]arene, Bu^tC4·Li₄, afforded two diantimony calix[4]arene complexes Bu^tD4(SbCl)₂, with different ¹H NMR spectra and different THF coordination, but the same core structures. Other calix[4]arene antimony complexes (HC4(SbCl)₂ 2 and AC4(SbCl)₂ 3, diantimony chloride complexes of calix[4]arene and p-allylcalix[4]arene) and calix[4]arene bismuth complexes (Bu ^tC4(BiCl₂)₂Li₂ 4, HC4(BiCl ₂)₂Li₂·6DMSO 5, and AC4(BiCl ₂)₂Li₂·4THF 6) were prepared by the reactions of MCl₃ (M = Sb or Bi) with RC4·Li₄ (R = Bu^t, H, or allyl) in a 2:1 molar ratio in THF. The same strategy was applied for Bu^tC8 (p-tert-butylcalix[8]arene), and the desired bismuth complex [Bu^tC8(BiCl₂)₄(μ-Cl) ₂Li₆][4THF·7DME] 12 was successfully synthesized. Complex 12 contains a planar Bi₄ core with four terminal chlorine atoms, which adopt a syn arrangement with respect to the plane defined by four bismuth atoms, and orient away from each other. A calix[4]arene monobismuth complex 11 was prepared by the reaction of Bi(OBu^t)₃ with the 1,2-disubstituted benzyl ether of calix[4]arene. Complexes 1-6 contain central planar M₂(μ-O)₂ (M = Sb or Bi) four-membered rings, similar to four-membered rings observed in other calix[4]arene main group metal complexes. Intramolecular bismuth-arene π interactions are observed in complexes 4-6 and 11 but not 12.

Full text of DOI:10.1021/ic801445m

Inorg. Chem. 2008, 47, 11143-11153
Synthesis and Characterization of Bismuth(III) and Antimony(III)
Calixarene Complexes
Lihua Liu,† Lev N. Zakharov,‡ James A. Golen,§ Arnold L. Rheingold,*,‡ and Tracy A. Hanna*,†
Department of Chemistry, Texas Christian UniVersity, P.O. Box 298860, Fort Worth, Texas 76129,
Department of Chemistry and Biochemistry, UniVersity of Massachusetts Dartmouth, North
Dartmouth, Massachusetts 02747, and Department of Chemistry and Biochemistry, UniVersity of
California San Diego, 9500 Gilman DriVe, m/c 0358, La Jolla, California 92093-0358
Received July 31, 2008
A series of calixarene bismuth and antimony complexes have been fully characterized by NMR, X-ray, IR, UV/vis,
and elemental analysis. The reactions of SbCl3 with the monosodium salt of p-tert-butylcalix[4]arene (ButC4),
ButC4· Na, and the tetralithium salt of para-tert-butylcalix[4]arene, ButC4·Li4, afforded two diantimony calix[4]arene
complexes ButC4(SbCl)2, with different 1H NMR spectra and different THF coordination, but the same core structures.
Other calix[4]arene antimony complexes (HC4(SbCl)2 2 and AC4(SbCl)2 3, diantimony chloride complexes of
calix[4]arene and p-allylcalix[4]arene) and calix[4]arene bismuth complexes (ButC4(BiCl2)2Li2 4, HC4(BiCl2)2Li2 · 6DMSO
5, and AC4(BiCl2)2Li2 · 4THF 6) were prepared by the reactions of MCl3 (M ) Sb or Bi) with RC4 ·Li4 (R ) But,
H, or allyl) in a 2:1 molar ratio in THF. The same strategy was applied for ButC8 (p-tert-butylcalix[8]arene), and the
desired bismuth complex [ButC8(BiCl2)4(µ-Cl)2Li6][4THF · 7DME] 12 was successfully synthesized. Complex 12
contains a planar Bi4 core with four terminal chlorine atoms, which adopt a syn arrangement with respect to the
plane defined by four bismuth atoms, and orient away from each other. A calix[4]arene monobismuth complex 11
was prepared by the reaction of Bi(OBut)3 with the 1,2-disubstituted benzyl ether of calix[4]arene. Complexes 1-6
contain central planar M2(µ-O)2 (M ) Sb or Bi) four-membered rings, similar to four-membered rings observed in
other calix[4]arene main group metal complexes. Intramolecular bismuth-arene π interactions are observed in
complexes 4-6 and 11 but not 12.
Introduction
bismuth aryloxide Bi(O-2,6-Me2C6H3)3,29 and Horley et al.
more recently reported the first antimony aryloxide Sb(O-
2,6-Me2C6H3)3.28 Whitmire et al. reported the fluoride-
containing bismuth aryloxides [Bi(µ-OC6F5)(OC6F5)2(Solv)]2
(Solv ) toluene, THF, cyclohexane),30,31 and recently Turner
et al. reported aminetris(phenoxide) bismuth and antimony
complexes.32 Our group has now synthesized and character-
ized an extensive series of bismuth aryloxides Bi(OAr)3 by
the reactions of simple phenols with bismuth amides.33
There has also been considerable and growing interest in
the metal coordination chemistry of calixarenes and calix-
arene derivatives as poly(dentate) ligands because of their
potential applications in homogeneous catalysis and model
systems, supramolecular chemistry, and material sci-
ences.34-36 Transition metal complexes of calixarenes have
received much attention over the last two decades,36-46 but
far fewer heavy main group complexes have been reported
(e.g., M ) As, Ge, Sn, Al, Zn).34,47-55
The coordination chemistry of bismuth and antimony is
currently attracting great interest because of its myriad
applications in organic and oxidation catalysis, medicine and
biochemistry, superconductors, ferroelectrics, and many other
oxide based materials.1-25 Chemists are focusing much
attention on the synthesis and identification of new bismuth
and antimony aryloxides/alkoxides that are suitable for these
applications.1,2,4,6,7,26-28
A number of bismuth alkoxides have now been reported
(recently reviewed by Mehring1), but few bismuth aryloxides,
or antimony alkoxides/aryloxides, have been structurally
characterized. Evans et al. reported the first monomeric
* To whom correspondence should be addressed. E-mail: t.hanna@tcu.edu.
Phone: 817-257-6197. Fax: 817-257-5851.
†
Texas Christian University.
University of California San Diego.
University of Massachusetts Dartmouth.
‡
§
10.1021/ic801445m CCC: $40.75  2008 American Chemical Society
Inorganic Chemistry, Vol. 47, No. 23, 2008 11143
Published on Web 10/30/2008

Liu et al.
sealed and evacuated capillary tubes on a Mel-Temp apparatus
(Laboratory Devices, Cambridge, MA) using a 400 °C thermometer
calibrated against a thermocouple. The melting points are uncor-
rected. A melting temperature preceded by a “>” sign indicates
that the compound starts to decompose at that temperature but
appears to actually melt at some higher temperature. 1H NMR and
13C NMR spectra were recorded on a Varian XL-300 spectrometer
We have a particular interest in the coordination chemistry
of bismuth,7,33,48,56,57 and have found that the chemistry of
bismuth, and even of antimony, frequently differs from that
of their lighter congeners. In 2004 we demonstrated that
calixarene frameworks are able to accommodate bismuth and
antimony.48 In an expansion of these studies, we report herein
the synthesis and X-ray characterization of a series of Bi(III)
and Sb(III) calixarene complexes.
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All reactions were carried out in a nitrogen-filled glovebox, unless
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11144 Inorganic Chemistry, Vol. 47, No. 23, 2008

Bismuth(III) and Antimony(III) Calixarene Complexes
Table 1. Summary of X-ray Data Collection Parameters
ButC4(BiCl)2 ·2LiCl·6THF (4·6THF)
HC4(BiCl)2 ·2LiCl·6DMSO (5·6DMSO)
AC4(BiCl)2 ·2LiCl·4THF (6·6THF)
formula
fw
cryst syst
space group
T, K
C74H112Bi2Cl4Li2O10
1735.28
C40H56Bi2Cl4Li2O10S6
1462.85
C56H68Bi2Cl4Li2O8
1442.74
monoclinic
P2(1)/n
100(2)
triclinic
triclinic
j
j
P1
P1
213(2)
213(2)
a, Å
b, Å
c, Å
12.7418(8)
13.1653(8)
13.6265(9)
114.8660(10)
111.9260(10)
90.1240(10)
1889.2(2)
1, 1
9.8018(5)
11.2845(9)
13.0660(7)
90.8250(10)
109.3610(10)
99.9690(10)
1338.88(12)
2, 1
11.2898(18)
17.171(3)
15.211(2)
90
110.594(2)
90
R, deg
ꢀ, deg
γ, deg
V, Å3
2760.3(7)
2, 1
Z, Z′
cryst dimens, mm
dcalcd, g/cm-3
µ, mm-1
2θ max, deg
Tmin/Tmax
0.20 × 0.15 × 0.10
0.30 × 0.18 × 0.05
0.39 × 0.21 × 0.12
1.525
1.814
1.736
4.847
56.34
0.612
7.045
56.26
0.422
6.621
55.00
0.800
N measd. [Rint
N ind
]
13757 [0.0201]
8510
9750 [0.0245]
6061
17135 [0.0205]
6288
N obs (I > 2(I))
no. of params
R (I > 2(I))
Rw (I > 2(I))
GOF
7869
401
0.0295
0.0758
5810
289
0.0401
0.1077
5550
325
0.0245
0.0607
1.046
1.098
1.051
Bn2C4(BiOtBu) (11)
HC4(SbCl)2 ·2DMSO (2·2DMSO)
ButC8(BiCl)4 ·6LiCl·6DME·3THF (12)
formula
fw
cryst syst
space group
T, K
C46H43Bi1O5
884.78
monoclinic
P2(1)
C32H32Cl2O6S2Sb2
891.10
monoclinic
P2(1)/n
213(2)
C149H238Bi4Cl10Li6O30
3741.46
triclinic
j
P1
100(2)
218(2)
a, Å
b, Å
c, Å
11.0005(6)
31.5851(18)
11.2779(6)
90
112.4710(10)
90
9.5564(4)
15.8074(7)
11.0846(5)
90
98.8210(10)
90
16.0081(9)
20.2527(10)
28.0539(15)
77.0410(10)
77.5000(10)
75.9260(10)
8470.5(8)
2, 1
R, deg
ꢀ, deg
γ, deg
V, Å3
3622.4(3)
4, 1
1654.65(13)
2, 1
Z, Z′
cryst dimens, mm
dcalcd, g/cm-3
µ, mm-1
2θ max, deg
Tmin/Tmax
0.37 × 0.20 × 0.17
0.15 × 0.10 × 0.08
0.35 × 0.20 × 0.10
1.622
1.789
1.467
4.916
55.02
1.963
55.34
0.806
4.364
56.30
0.594
N measd. [Rint
N ind
]
30577 [0.0270]
15662
14108 [0.0230]
7286
61607 [0.0235]
38331
N obs (I > 2(I))
no. of params
R (I > 2(I))
Rw (I > 2(I))
GOF
14593
937
0.0254
0.0492
0.789
6745
263
0.0351
0.0787
26148
1643
0.0392
0.1001
1.102
0.970
at 300 and 75 MHz, respectively. Analytical samples were dried
in a drying pistol under vacuum for at least 24 h. Microanalyses
were performed by Microanalysis Laboratory, University of Illinois,
Urbana-Champaign, Urbana, IL. IR and UV/vis spectra were
obtained with an Infinity Gold FTIR spectrometer and Agilent 8453
spectrophotometer respectively. Filtrations used a medium sintered
glass filter.
in THF (3.0 mL), and a light yellow solution was formed. The
reaction mixture was stirred overnight at room temperature. A
solution of SbCl3 (0.23 g, 1.0 mmol) in THF (3.0 mL) was added
to the solution of calixarene lithium salt, and a white suspension
was immediately obtained. The mixture was stirred overnight at
room temperature. The insoluble material was removed by cen-
trifugation, and a colorless solution was obtained. The filtrate was
dried under vacuum to afford 1 as a white powder which was
recrystallized from THF-pentane to give colorless crystals (0.54 g,
Synthesis of ButC4(SbCl)2 (1). Method A.48 To a solution of
ButC4·Na (0.27 g, 0.40 mmol) in THF was added a solution of
SbCl3 (0.18 g, 0.80 mmol), and a white suspension was obtained.
The reaction mixture was stirred overnight at room temperature.
Removal of insoluble material (ButC4) gave a colorless solution.
The solvent was reduced to half-volume, the solution put into the
freezer (-35 °C) for several days, and colorless X-ray quality
crystals of 1 (0.28 g, 69% yield) were obtained.
1
78% yield). H NMR (THF-d8): δ 7.15 (s, 4H, ArH), 7.14 (s, 4H,
ArH), 4.41 (d, J ) 15.4 Hz, 4H, ArCH2Ar), 3.53 (d, J ) 15.4 Hz,
4H, ArCH2Ar), 1.34 (s, 18H, C(CH3)3), 1.26 (s, 18H, C(CH3)3).
No 13C NMR data is available because of the poor solubility in
THF. IR (nujol, cm-1): 2724w, 2672w, 1588w, 1553w, 1537w,
1463vs, 1411w, 1377s, 1364m, 1311w, 1286w, 1260m, 1205m,
1189s, 1106m, 1025m, 979w, 925w, 913w, 880m, 866w, 831m,
823s, 804s, 757s, 745w, 723m, 684w. Anal. Calcd for
Method B. To a suspension of ButC4 (0.32 g, 0.50 mmol) in
THF (8.0 mL) was added a solution of LiOBut (0.16 g, 2.0 mmol)
Inorganic Chemistry, Vol. 47, No. 23, 2008 11145

Liu et al.
Figure 3. ORTEP diagram of 4a. The ellipsoids are shown at 50%
probability, and the H atoms are not shown for clarity.
Figure 1. Oak Ridge Thermal Ellipsoid Plot (ORTEP) diagram of 1·4THF.
The ellipsoids are shown at 30% probability, and the H atoms and
noncoordinated solvent molecules are not shown for clarity.
Figure 4. ORTEP diagram of 4b. The ellipsoids are shown at 30%
probability, and the H atoms are not shown for clarity.
Figure 2. ORTEP diagram of 2·2DMSO. The ellipsoids are shown at 30%
probability, and the H atoms are not shown for clarity.
was stirred overnight at room temperature. The insoluble material
was collected on a medium pore frit, and a light yellow solution
remained. The solid was extracted with DMSO, and the DMSO
mixture was centrifuged to remove black insoluble material. The
resulting DMSO solution was combined with the THF mother
liquor. The combined solution was left untouched for 4 h at room
temperature and colorless crystals (0.30 g, 61% yield) formed. 1H
NMR (DMSO-d6): δ 7.00 (m, 8H, ArH), 6.73 (m, 4H, ArH), 4.34
(d, J ) 15.0 Hz, 4H, ArCH2Ar),3.43 (d, J ) 15.0 Hz, 4H,
ArCH2Ar). No 13C NMR data is available because of the poor
solubility in DMSO. IR (nujol, cm-1): 1589w, 1455vs, 1377s,
1305w, 1252s, 1235m, 1205s, 1196s, 1166w, 1083m, 1075m,
1050m, 968w, 908w, 883m, 854s, 778s, 773s, 765s, 743w, 715m,
617s. Anal. Calcd for C28H20Cl2O4Sb2 ·DMSO: C, 44.32; H, 3.22.
Found: C, 44.46; H, 3.52. mp: > 360 °C. UV/vis λmax/nm (THF)
(ε/dm3 mol-1 cm-1): 252 (6.0 × 103), 266 (5.8 × 103), 272 (5.3 ×
103), 281 (3.9 × 103).
Table 2. Selected Bond Lengths (Å) and Angles (deg) of 1·4THF and
2·2DMSO
1·4THF
2·2DMSO
Sb(1)-O(2)
Sb(1)-O(1)
Sb(1)-O(3)
1.9839(18)
2.0345(17)
2.569(2)
Sb(1)-O(1A)
Sb(1)-O(2A)
Sb(1)-O(3)
Sb(1)-O(2)
Sb(1)-Cl(1)
1.991(2)
2.027(2)
2.405(2)
2.447(2)
2.4446(8)
Sb(1)-O(1A) 2.4363(17)
Sb(1)-Cl(1)
O(2)-Sb(1)
-O(1)
2.4197(8)
88.15(7)
O(1A)-Sb(1)-O(2A) 86.92(8)
O(2)-Sb(1)
-O(1A)
O(1)-Sb(1)
-O(1A)
Sb(1)-O(2)
-Sb(1A)
Caryl-O-Sb
81.24(6)
65.98(5)
114.02(8)
O(1A)-Sb(1)-O(3)
O(2A)-Sb(1)-O(3)
O(1A)-Sb(1)-O(2)
O(2A)-Sb(1)-O(2)
78.29(8)
164.33(8)
81.08(7)
65.79(8)
114.64(14)
-131.26(15)
O(3)-Sb(1)-O(2)
Sb(1)-O(2)-Sb(1A)
Caryl-O-Sb
116.19(8)
114.21(8)
115.09(16)
-130.66(17)
Synthesis of AC4(SbCl)2 (3). The procedure is the same as that
for 2, but using AC4 (0.29 g, 0.50 mmol), LiOBut (0.17 g, 2.0
mmol), and SbCl3 (0.23 g, 1.0 mmol). The product was recrystal-
lized from DMSO-toluene (1:10). The yield is 0.32 g (71%).1H
NMR (THF-d8): δ 6.90 (s, 4H, ArH), 6.85 (s, 4H, ArH), 6.03-5.87
(m, 4H, CH2-CH ) CH2), 5.12-4.89 (m, 8H, CH2-CH)CH2),
4.43 (d, J ) 15.4 Hz, 4H, ArCH2Ar), 3.40 (d, J ) 15.4 Hz, 4H,
ArCH2Ar), 3.32 (d, J ) 6.2 Hz, 4H, CH2-CH)CH2), 3.23 (d, J )
6.6 Hz, 4H, CH2-CH)CH2). 13C NMR (THF-d8): δ 154.88, 151.14,
139.43, 135.55, 134.57, 133.92, 133.84, 129.24, 128.80, 115.45
(aromatic carbons and carbons from CH2)CH of allyl groups),
40.83, 35.66 (methylene carbons from calix[4]arene and allyl
C44H52Cl2O4Sb2 ·2THF: C, 55.09; H, 5.78. Found: C, 55.40; H, 5.78.
mp: >190 °C (dec.). UV/vis λmax/nm (THF) (ε/dm3 mol-1 cm-1):
267 (1.2 × 104), 272 (1.1 × 104), 287 (8.6 × 103).
Synthesis of HC4(SbCl)2 (2). To a solution of HC4 (0.21 g,
0.50 mmol) in THF (6.0 mL) was added a solution of LiOBut (0.17
g, 2.0 mmol) in THF (4.0 mL), and a light yellow suspension was
obtained after 20 min. The reaction mixture was stirred overnight
at room temperature, and a solution of SbCl3 (0.23 g, 1.0 mmol) in
THF (3.0 mL) was added. A white suspension was obtained, which
11146 Inorganic Chemistry, Vol. 47, No. 23, 2008

Bismuth(III) and Antimony(III) Calixarene Complexes
Figure 5. ORTEP diagram of 5; anion (A) and cation (B). The ellipsoids are shown at 30% probability, and the H atoms are omitted for clarity.
125.77 (aromatic carbons), 35.18 (ArCH2Ar), 35.01, 34.66
(C(CH3)3), 32.90, 32.67 (C(CH3)3). IR (nujol, cm-1): 2724w, 1764w,
1588w, 1553w, 1537w, 1462vs, 1410m, 1393m, 1377s, 1363s,
1306s, 1280s, 1250vs, 1200vs, 1115m, 1104m, 1048s, 991w, 913s,
894s, 878s, 868m, 830s, 824s, 805s, 752s, 723w, 701w, 682w. Anal.
Calcd for C44H52Bi2Cl2O4 ·2THF·2LiCl: C, 45.83; H, 5.07. Found:
C, 45.98; H, 5.10. mp: 335 °C (dec.). UV/vis λmax/nm (DMSO)
(ε/dm3 mol-1 cm-1): 259 (3.9 × 103), 295 (2.9 × 103), 308 (2.8 ×
103).
Method B. To a suspension of ButC4 (0.32 g, 0.50 mmol) in
THF (8.0 mL) a yellow solution of ClBi(NCy2)2 (0.60 g, 1.0 mmol)
in THF (5.0 mL) was added. The resulting mixture was stirred for
4 days. Removal of insoluble material by centrifugation gave a
yellow solution. The filtrate was dried under vacuum to give 4,
which was recrystallized with THF/pentane or DME/hexane to
provide yellow crystals (0.57 g, 84% yield).
Synthesis of HC4(BiCl2)2Li2 ·6DMSO (5). To a solution of HC4
(0.21 g, 0.50 mmol) in THF (6.0 mL) was slowly added a solution
of 2.0 M BunLi in pentane (1.0 mL, 2.0 mmol) to obtain a light
yellow suspension. The reaction mixture was stirred for 4 h at room
temperature. A solution of BiCl3 (0.32 g, 1.0 mmol) in THF (3.0
mL) was added to the resulting suspension of calix[4]arene lithium
Figure 6. ORTEP diagram of 6. The ellipsoids are shown at 30%
probability, and the H atoms are omitted for clarity.
salt,68 and a dark suspension was obtained. The mixture was stirred
overnight at room temperature. The insoluble material was collected
by filtration, and a yellow solution remained. The solid was
extracted with anhydrous DMSO (3.0 mL); then the mixture was
centrifuged to remove the black insoluble material. The DMSO
solution was combined with the mother liquor, and then an
additional 10 mL of THF was added to the combined solutions.
The resulting solution was allowed to settle for 2 h, and X-ray
groups). IR (nujol, cm-1): 2724w, 1637m, 1593w, 1575w, 1463vs,
1424m, 1377s, 1312m, 1287w, 1274w, 1260m, 1243m, 1204s,
1138s, 1133s, 1097m, 1016w, 1002w, 994m, 967w, 913s, 879m,
864w, 813s, 780s, 743m, 705m, 682w, 666w, 605s. Anal. Calcd
for C40H36Cl2O4Sb2 ·2DMSO: C, 53.26; H, 4.60. Found: C, 53.15;
H, 4.95. mp: 279 °C (dec.). UV/vis λmax/nm (THF) (ε/dm3 mol-1
cm-1): 266 (9.3 × 103), 276 (8.0 × 103), 288 (6.3 × 103).
Synthesis of ButC4(BiCl2)2Li2 (4). Method A. To a suspension
of ButC4 (0.32 g, 0.50 mmol) in THF (5.0 mL) was added a
solution of LiOBut (0.16 g, 2.0 mmol) or BunLi (1.0 mL, 2.0 M)
at room temperature. The reaction mixture was stirred for 4 h, and
then a solution of BiCl3 (0.32 g, 1.0 mmol) in THF (3.0 mL) was
added; immediately a yellow suspension was obtained. The resulting
mixture was stirred overnight. Removal of the insoluble material
by centrifugation gave a yellow solution. The filtrate was pumped
dry to give 4 as yellow powder, which was recrystallized by pentane
diffusion into its THF solution to afford yellow crystals (0.46 g,
69%). 1H NMR (DMSO-d6): δ 7.07 (s, 4H, ArH), 6.99 (s, 4H, ArH),
4.33 (d, J ) 15.0 Hz, 4H, ArCH2Ar), 3.63 (d, J ) 15.0 Hz, 4H,
1
quality light yellow crystals (0.45 g, 62% yield) were formed. H
NMR (DMSO-d6): δ 7.01 (d, J ) 7.5 Hz, 4H, ArH), 6.95 (d, J )
7.5 Hz, 4H, ArH), 6.59 (t, J ) 7.5 Hz, 2H, ArH), 6.48 (t, J ) 7.5
Hz, 2H, ArH), 4.32 (d, J ) 15.0 Hz, 4H, ArCH2Ar), 3.63 (d, J )
15.0 Hz, 4H, ArCH2Ar). No 13C NMR data is available because of
the poor solubility in DMSO. IR (nujol, cm-1): 2723w, 1668w,
1579m, 1455vs, 1422s, 1377s, 1312w, 1298m, 1259s, 1212s,
1171w, 1158w, 1099w, 1072m, 1039vs, 1025vs, 1000vs, 959s,
938m, 913w, 900m, 878m, 850s, 807s, 767s, 757s, 748m, 720m,
709m, 676w, 609m. Anal. Calcd for (C28H20Bi2Cl2O4 ·
6DMSO ·2LiCl): C, 32.75; H, 3.97. Found: C, 33.11; H, 4.08. mp:
> 350 °C (165-167 °C appears to lose DMSO). UV/vis λmax/nm
(THF): 283, 303 (absorption coefficient ε is not available because
of the limited solubility).
1
ArCH2Ar), 1.30 (s, 18H, (CH3)3C), 1.25 (s, 18H, (CH3)3C). H
NMR (THF-d8): δ 7.20 (s, 4H, ArH), 7.07 (s, 4H, ArH), 4.44 (d,
J ) 15.0 Hz, 4H, ArCH2Ar), 3.71 (d, J ) 15.0 Hz, 4H, ArCH2Ar),
1.30 (s, 18H, (CH3)3C), 1.27 (s, 18H, (CH3)3C). 13C NMR (THF-
d8): δ 154.81, 152.04, 145.02, 144.41, 136.58, 135.60, 130.98,
(68) Guillemot, G.; Solari, E.; Rizzoli, C.; Floriani, C. Chem.sEur. J. 2002,
8, 2072–2080.
Inorganic Chemistry, Vol. 47, No. 23, 2008 11147

Liu et al.
Table 3. Selected Bond Lengths (Å) and Angles (deg) of 4a and 4b
4a
4b
Bi(1)-O(1)
Bi(1)-O(2A)
Bi(1)-O(2)
Bi(1)-Cl(2)
Bi(1)-Cl(1)
Cl(1)-Li(1)
O-Li(1)
2.1698(12)
2.2256(12)
2.3891(12)
2.5616(5)
2.7715(5)
2.367(4)
Bi(1)-O(2A)
Bi(1)-O(1A)
Bi(1)-O(1)
Bi(1)-Cl(2)
Bi(1)-Cl(1)
Cl(1)-Li(1)
O-Li(1)
2.125(2)
2.245(2)
2.364(2)
2.6106(10)
2.7847(11)
2.328(8)
1.905(4)-2.003(4)
1.913(9)-1.940(9)
O(1)-Bi(1)-O(2A)
O(1)-Bi(1)-O(2)
O(2)-Bi(1)-O(2A)
Cl(2)-Bi(1)-Cl(1)
Caryl-O-Bi
81.85(4)
80.10(4)
65.26(5)
92.112(16)
118.47(10)-126.78(11)
114.74(5)
O(2A)-Bi(1)-O(1A)
O(2A)-Bi(1)-O(1)
O(1A)-Bi(1)-O(1)
Cl(2)-Bi(1)-Cl(1)
Caryl-O-Bi
84.30(9)
81.68(8)
65.83(9)
107.17(4)
117.17(19)-123.0(2)
114.17(9)
Bi(1)-O(2)-Bi(1A)
Bi(1A)-O(1)-Bi(1)
Table 4. Selected Bond Lengths (Å) and Angles (deg) of 5 and 6
5
6
Bi(1)-O(2)
Bi(1)-O(1)
Bi(1)-O(1A)
Bi(1)-Cl(2)
Bi(1)-Cl(1)
O-Li(1)
2.124(3)
2.300(3)
2.362(3)
2.6067(13)
2.7239(15)
1.890(9)-1.958(10)
Bi(1)-O(1)
Bi(1)-O(2A)
Bi(1)-O(2)
Bi(1)-Cl(2)
Bi(1)-Cl(1)
O-Li(1)
2.167(2)
2.227(2)
2.441(2)
2.5386(8)
2.7907(8)
1.921(6)-1.957(6)
O(2)-Bi(1)-O(1)
O(2)-Bi(1)-O(1A)
O(1)-Bi(1)-O(1A)
Cl(2)-Bi(1)-Cl(1)
Caryl-O-Bi
83.02(11)
81.79(11)
65.47(13)
98.50(4)
118.2(2)-125.1(3)
114.53(13)
O(1)-Bi(1)-O(2A)
O(1)-Bi(1)-O(2)
O(2A)-Bi(1)-O(2)
Cl(2)-Bi(1)-Cl(1)
Caryl-O-Bi
82.56(7)
80.85(7)
63.93(8)
87.54(3)
118.23(17)-125.69(17)
116.07(8)
Bi(1)-O(2)-Bi(1A)
Bi(1A)-O(1)-Bi(1)
Table 5. Selected Structural Parameters for 4-6 and 11
Bi-C(aryl)/Å Bi· · ·centroid (aryl)/Å Bi · · ·Bi/Å
4a 3.343-3.468
4b 3.362-3.432
formed. The reaction mixture was transferred to a 50 mL solvent
bomb and heated for 6 h at 95 °C. An orange yellow suspension
was obtained. While the suspension was hot, removal of the black
precipitate by centrifugation gave an orange yellow solution which
was left untouched for 3 h to give orange red crystals. H NMR
and X-ray characterization were unsuccessful.
3.098
3.103
3.157
3.887
3.870
3.922
3.962
1
5
6
3.432-3.478
3.399-3.481
3.146
3.060, 3.736
11 3.243-3.474, 3.303-4.573
Synthesis of Bismuth Complex of 1,2-Dibenzyl Ether of
Calix[4]arene (11). To a solution of 9 (0.30 g, 0.50 mmol) in
THF (8.0 mL) was added a solution of Bi(OBut)3 (0.21 g, 0.50
mmol) in THF (3.0 mL), and the reaction mixture was stirred
overnight at room temperature. The solvent was evaporated under
vacuum, and a yellow residue was obtained. The residue was
triturated with pentane to give a light yellow solid. The crude
product was recrystallized by pentane diffusion into its THF
solution, and needle crystals (0.29 g, 66% yield) were obtained.
1H NMR (C6D6): δ 7.33 (d, J ) 7.5 Hz, 2H, ArH), 7.01 (two
triplets partially overlap at 7.02 ppm and 7.00 ppm, J ) 7.5
and 6.6 Hz, 8H, ArH), 6.87 (d, J ) 7.0 Hz, 2H, ArH), 6.77
(two triplets partially overlap at 6.77 ppm, J ) 7.5 and 6.6 Hz,
4H, ArH), 6.59 (t, J ) 7.5 Hz, 4H, ArH), 6.40 (d, J ) 7.0 Hz,
2H, ArH), 5.57 (d, J ) 12.3 Hz, 1H, ArCH2Ar), 4.40 (d, J )
16.3 Hz, 2H, ArCH2Ar), 4.14 (d, J ) 11.9 Hz, 2H, CH2 from
Bn, AB pattern), 3.94 (d, J ) 11.9 Hz, 2H, CH2 from Bn, AB
pattern), 3.84 (d, J ) 12.3 Hz, 1H, ArCH2Ar), 3.58 (two doublets
partially overlap at 3.56 ppm, J ) 16.3 and 12.8 Hz, 3H,
ArCH2Ar), 2.67 (d, J ) 12.8 Hz, 1H, ArCH2Ar), 1.50 (s, 9H,
OC(CH3)3). 13C NMR (C6D6): δ 155.9, 155.0, 138.7, 138.2,
136.9, 136.5, 131.7, 131.2, 129.4, 128.6, 128.5, 128.2, 127.8,
127.5, 125.3, 121.0 (aromatic carbons), 75.6 (OCH2C6H5), 38.8
(CH2), 36.0 (OC(CH3)3), 31.0, 29.9 (CH2) (one carbon from
OC(CH3)3 missing). IR (nujol, cm-1): 2724w, 2671w, 1584w,
1495m, 1459vs, 1377vs, 1305w, 1260m, 1214w, 1169w, 1158w,
1093s, 1017s, 969w, 915w, 901w, 805s, 770w, 751m, 723s,
699m. Anal. Calcd for C46H43Bi1O5: C, 62.44; H, 4.90. Found:
Synthesis of AC4(BiCl2)2Li2 ·4THF (6). To a solution of AC4
(0.29 g, 0.50 mmol) in THF (5.0 mL) was added a solution of
LiOBut (0.17 g, 2.0 mmol) in THF (3.0 mL), and the reaction
mixture was stirred for 4 h at room temperature. A solution of BiCl3
(0.32 g, 1.0 mmol) in THF (3.0 mL) was added to the resulting
lithium salt suspension, and a yellow suspension was obtained. The
resulting suspension was stirred overnight at room temperature.
Removal of insoluble material by centrifugation gave a yellow
solution. The solvent was slowly reduced to one-fifth under vacuum,
1
and yellow crystals were obtained (0.43 g, 60% yield). H NMR
(DMSO-d6): δ 6.95 (s, 4H, ArH), 6.90 (s, 4H, ArH), 6.05-5.81
(m, 4H, CH2-CH)CH2), 5.16-4.96 (m, 8H, CH2-CH)CH2), 4.26
(d, J ) 15.0 Hz, 4H, ArCH2Ar), 3.75 (d, J ) 15.0 Hz, 4H,
ArCH2Ar), 3.42 (d, J ) 6.6 Hz, 4H, CH2-CH)CH2), 3.34 (d, J )
7.0 Hz, 4H, CH2-CH)CH2). IR (nujol, cm-1): 1638m, 1593w,
1567w, 1505w, 1464vs, 1451vs, 1429s, 1377m, 1330w, 1306s,
1268s, 1247s, 1233vs, 1222vs, 1182w, 1144m, 1132m, 1085m,
1044s, 998m, 928s, 915vs, 874s, 810s, 801vs, 749m, 711m, 667w.
Anal. Calcd for C40H36Bi2Cl2O4 ·4THF ·2LiCl: C, 46.62; H, 4.75.
Found: C, 46.57; H, 4.95. mp: 310 °C (110 °C lost THF). UV/vis
λ
max/nm (DMSO) (ε/dm3 mol-1 cm-1): 257 (6.0 × 103), 296 (4.2
× 103), 306 (4.0 × 103).
Reactions of 1,3-Dimethyl Ethers of Calix[4]arenes (7 and
8) with Bi[N(SiMe3)2]3. To a solution of 1,3-dimethyl ether of
calix[4]arene (0.50 mmol, 0.34 g for 7 and 0.23 g for 8) in toluene
(10 mL) was added a solution of Bi[N(SiMe3)2]3 (0.35 g, 0.50
mmol) in toluene (6 mL), and immediately a yellow solution was
11148 Inorganic Chemistry, Vol. 47, No. 23, 2008

Bismuth(III) and Antimony(III) Calixarene Complexes
C, 62.11; H, 4.87. mp: 189-191 °C. UV/vis λmax/nm (DMSO)
(ε/dm3 mol-1 cm-1): 267 (2.7 × 103), 282 (2.3 × 103), 294 (2.1
× 103), 313 (1.4 × 103).
be expected, the product yield is highest (>60%) if 2-4
equiv of SbCl3 is used; a 1:1 ratio gave only a 29% yield.
The reaction of the de-tert-butylated monoanion, HC4 · Na,
with SbCl3 could not form 2 and only HC4 was recovered.
In contrast, the reactions of SbCl3 with RC4· Na4 (R )
H, But, or allyl) gave the corresponding products 1, 2, and
3 in >60% yield (eq 1). Complexes 1-3 were purified by
recrystallization from THF/DMSO, THF, and THF/hexane,
respectively. All complexes have limited solubility in organic
solvents, but the solubility of 3 is much better than that of
1 and 2.
Synthesis of [ButC8(BiCl2)4(µ-Cl)2Li6][4THF·7DME] (12). To
a suspension of ButC8 (0.32 g, 0.25 mmol) in THF (8 mL) was
slowly added a solution of 2.0 M BunLi (2.0 mL), and an orange
yellow solution was obtained. The mixture was stirred for 4 h, and
then a solution of BiCl3 (0.63 g, 1.00 mmol) in THF (4 mL) was
added. Immediately a black suspension was formed. The resulting
mixture was stirred overnight. The insoluble material was removed
by centrifugation to give a yellow solution. The volume of the
solution was reduced to one-fifth under vacuum, and yellow crystals
precipitated at room temperature (0.59 g, 78% yield). No NMR
data is available because of extremely poor solubility in organic
solvents after recrystallization. Single crystals suitable for X-ray
crystal structure analysis were obtained by hexane diffusion into
its THF/DME (1:3) solution at room temperature. IR (nujol, cm-1):
ν 1627w, 1481s, 1462vs, 1392m, 1378s, 1363s, 1293m, 1260m,
1202s, 1154w, 1118m, 1086w, 1042m, 944w, 912w, 875m, 817m,
801m, 728m. Anal. Calcd (%) for C88H104Bi4Cl10Li6O8 ·7THF: C,
46.03; H, 5.33. Found (%): C 45.84, H, 5.65; mp: > 360 °C. UV/
vis λmax/nm (THF) (ε/dm3 mol-1 cm-1): 263 (2.6 × 104), 288 (2.7
× 104), 332 (1.6 × 104).
X-ray Crystallography. X-ray diffraction data were collected
on a Bruker SMART APEX CCD diffractometer at 100 K (4a, 6,
11) and 213 K (1, 2, 4b, 5, 12) using Mo KR radiation. Data were
integrated and corrected for Lorentz and polarization effects using
SAINT.69 Absorption corrections in all cases were applied by
SADABS.70 Structures were solved using direct methods or the
Patterson function, completed by subsequent difference Fourier
syntheses, and refined by full matrix least-squares procedures on
F2. Some molecules were refined with restrictions on the bond
distances; in the refinement, typical average values were used as
targets for corresponding bond distances. All non-hydrogen atoms
were refined with anisotropic displacement coefficients, except
atoms of disordered fragments which were refined with isotropic
thermal parameters. The H atoms in 2 and 4a were found from the
residual density and refined with isotropic thermal parameters. H
atoms in other structures were refined in a rigid group model. Highly
disordered pentane and hexane solvent molecules sharing the same
positions in 4a and disordered THF solvent molecules in 12 were
treated by SQUEEZE.71 Corrections of the X-ray data by SQUEEZE,
210 and 366 electron/cell, were close to the required values of 184
and 320 electron/cell, respectively, for two pentane and two hexane
molecules in the full unit cell of 4a and eight THF molecules in
the full unit cell of 12. All calculations were performed using the
SHELXTL suite of programs.69 A summary of X-ray collection
parameters is given in Table 1.
The analogous reaction of RC4 · M monoanion (R ) H
or But; M ) Li, Na, or K) with BiCl3 yielded an intractable
yellow solid that was insoluble in organic solvents. Again
the tetraanion RC4 · Li4 (R ) H, But, or allyl) was more
reliable, but the reaction stoichiometry was important.
The molar ratio of 1 RC4 · Li4 to 2 BiCl3 in THF gave a
single air-sensitive product (4-6) (eq 2). When other ratios
were used, a soluble yellow solid was formed, that decom-
posed to calix[4]arene and an unidentified black solid at room
temperature. Products 4-6 were purified by recrystallization
from THF-hexane (1:3). Their solubility depends on the
substituents at the para position of calix[4]arene, and the
order of their solubility is 6 > 4 > 5.
Results and Discussion
Lattman et al.55 compared phosphorus and arsenic calix-
arene complexes; whereas solely monophosphorus deriva-
tives were observed, arsenic led to either mono- or diarsenic
derivatives depending on reaction stoichiometry. As we
continue down the periodic table, we find that both Sb and
Bi form solely the dimetal derivatives irrespective of reaction
stoichiometry. This is similar to other metals such as zinc
and postulated to occur via an unstable monometallic
intermediate.47 Presumably the starting calixanion is proto-
nated to form the side product calixarene, forming the
unstable anionic monometallocalixarene intermediate that is
Synthesis. We have communicated the synthesis of the
first antimony calixarene complex, 1.48 For this compound,
the calix[4]arene tetraanion (ButC4·Li4)68 is a more reliable
precursor than the monoanion (ButC4 · Na).65 The reaction
of the monoanion and SbCl3 always produced a mixture of
parent calix[4]arene (ButC4) and the product 1.48As might
(69) SMART, SAINT, and SHELXTL, Versions 6.10; Bruker AXS Inc.:
Madison, WI, 2000.
(70) Sheldrick, G. M. SADABS; University of Go¨ttingen: Go¨ttingen,
Germany, 1995.
(71) van der Sluis, P. V.; Speck, A. L. Acta Crystallogr. 1990, A46, 194–
201.
Inorganic Chemistry, Vol. 47, No. 23, 2008 11149

Liu et al.
be directly prepared by the reaction of 9 with Bi(OBut)3 (eq
3, condition b).
trapped with a second equivalent of metal. Monobismuth
derivatives were obtained only by blocking two of the
calixarene phenol groups, below.
As mentioned above, the molar ratio of calixarene to BiCl3
is a key factor for forming stable bismuth complexes. We
have found that the best molar ratio of oxygen atoms to
bismuth atom is 2:1 for making calix[4]arene bismuth
complexes.Wethentriedtoapplythisstrategytocalix[8]arenes.
The desired calix[8]arene bismuth complex was successfully
synthesized by the reaction of octalithium salt of ButC8 with
BiCl3 in a 1:4 ratio in THF at room temperature. After
recrystallization by hexane diffusion into its THF/DME (1:
2) solution, [ButC8(BiCl2)4(µ-Cl)2][6Li·4THF·7DME] (12)
was obtained. This complex was extremely air-sensitive and
had very limited solubility in organic solvents.
To obtain calix[4]arene monobismuth complexes, we
explored the reactions of the dialkyl ethers as dianionic
macrocyclic ligands with suitable bismuth and antimony
precursors (similar to the strategy used by Atwood et al. to
make monoaluminum calixarene complexes53). The reactions
of BiCl3 with the salts of 1,3-dimethyl ethers of calixarenes
(7 and 8) yielded orange yellow powders that were both
unstable and insoluble in most organic solvents. There was
no reaction at room temperature when 7 and 8 were treated
with Bi[N(SiMe3)2]3. Heating to 90-100 °C in toluene
provided orange red crystals with complex NMR spectra.
Although this compound appeared to contain bismuth, the
orange red crystals decomposed to parent calixarene and
unidentified insoluble material after 3 days. Demethylation
was observed when 7 and 8 were treated with Sb[N(SiMe3)2]3
in toluene at 90-100 °C.
Spectral Data. The calix[4]arene antimony complexes
1 · 3THF and 1 · 4THF, prepared from the mono- or tetraan-
1
ions, display different H NMR spectra. The calix[4]arene
antimony complex 1 · 3THF prepared by the reaction of
ButC4Na with SbCl3 exhibits two pairs of doublets for the
methylene groups at 4.45, 4.36, 3.74, and 3.39 ppm, two
doublets for aromatic protons at 7.21 and 7.12 ppm, and two
singlets for tert-butyl groups at 1.35 and 1.26 ppm in THF-
d8. The calix[4]arene antimony complex 1 · 4THF prepared
by the reaction of ButC4Li4 with SbCl3 shows only one pair
of doublets for methylene groups at 4.41 and 3.53 ppm, two
singlets for the aromatic protons at 7.15 and 7.14 ppm, and
two singlets for tert-butyl groups at 1.34 and 1.26 ppm.
However, both of the calix[4]arene antimony complexes
show the same core crystal structures; just different THF
coordination. We do not have an explanation for this
observation.
On the basis of the 1,2-disubstitution pattern observed in
calix[4]arene bismuth and antimony complexes, we consid-
ered 1,2-dialkyl ethers of calix[4]arenes as potential sup-
porting ligands. The dibenzylated calix[4]arene 9 was chosen
as a ligand for bismuth complexes because of its ease of
synthesis.64 Treatment of 9 with NaOBut and BiCl3 in THF
gave the product 10 (eq 3, condition a). However, 10
decomposed to 9 and black solid during recrystallization.
Complex 10 was therefore treated with 1 equiv of NaOBut
at -78 °C to afford a stable compound 11, which can also
1
The H NMR spectra of bismuth complexes 4-6 (R )
H, But, and allyl) show one pair of doublets for the methylene
groups and two kinds of aromatic protons, which is typical
for the flattened partial cone conformation of calix[4]arene
complexes.49,51-54 The H NMR spectrum of 11 displays
1
one singlet for OBut at 1.50 ppm (in comparison to that of
Bi(OBut)3 at 1.43 ppm) and three pairs of doublets at 5.57,
11150 Inorganic Chemistry, Vol. 47, No. 23, 2008

Bismuth(III) and Antimony(III) Calixarene Complexes
Figure 7. ORTEP diagram of 11. The ellipsoids are shown at 30%
probability, and the H atoms are not shown for clarity.
4.39, 3.84, 3.59, 3.58, and 2.45 ppm for methylene groups
of calix[4]arene, which is a typical pattern of methylene
groups in the 1,2-alternate conformation. The benzyl meth-
ylene groups give one pair of doublets at 4.14 and 3.94 ppm
because of the diastereostopic protons.64 The 13C NMR
spectrum of 11 shows three peaks for methylene carbons of
calix[4]arene at 38.8, 31.0, and 29.9 ppm, which indicates
that calix[4]arene has proximal substituents on the lower rim.
A total of 16 peaks for aromatic carbons were observed in
its 13C NMR spectrum (only 12 peaks should theoretically
be observed) because of the bismuth-arene π interaction in
the molecule (this has been confirmed by its X-ray crystal
structure, see next section). For 12 no NMR data is available
because of poor solubility.
All calixarene bismuth and antimony complexes are air-
sensitive and readily decompose to the corresponding calix-
arenes and other insoluble materials when exposed to air in
solution for ∼15 min. Treatment of complexes 1-6 with
strong bases led to decomposition.
Crystal and Molecular Structures. Calixarene Anti-
mony Complexes. The crystal structures of 1 and 2 are
shown in Figures 1 and 2, and selected bond lengths and
angles are listed in Table 2. The compounds are isostructural
with their arsenic analogues,55 displaying the flattened partial
cone conformation and M2(µ-O)2 cores typical of main group
metallocalixarenes,49,51-54 and similar to compounds 4-6
(see next section). The Sb2(µ-O)2 cycles in 1 and 2 are
asymmetric; the Sb-O bond lengths are 2.027(2) and
2.447(2) Å for 2 · 2DMSO and 2.0345(17) and 2.4363(17)
Å for 1 · 4THF. The coordination of the Sb atom in 1 · 4THF
and 2 · 2DMSO can be described as a distorted square
pyramid. The apical Sb-O lengths (1.9839(18) and 1.991(2)
Å, respectively, in 1 and 2) are close to the short Sb-O
length in the central Sb2(µ-O)2 cycles, and a little longer than
the Sb-O bonds in Sb(O-2,6-Me2C6H3)3 (1.967-1.976 Å).28
Figure 8. ORTEP diagram of 12 (anion and cations). The ellipsoids are
shown at 30% probability, and the H atoms and noncoordinated solvents
are omitted for clarity.
metallocalixarenes, with a flattened partial cone conformation
of the calixarene ring and a central planar Bi2(µ-O)2 core. In
this case, though, the overall complex is dianionic because of
coordination of another Cl- on each bismuth atom. This
difference may be due to the larger size and/or greater Lewis
acidity of bismuth compared to its lighter congeners. Complexes
4-6 contain central planar Bi2(µ-O)2 four-membered rings
bearing two trans terminal chlorine atoms and two trans
bridging chlorine atoms. Each bismuth atom in these four
structures is five-coordinate with a distorted square-based
pyramidal geometry in which the apical site is occupied by an
oxygen atom from a phenolate and the basal plane consists of
two cis chlorine atoms and two cis oxygen atoms from
phenolates. Each bismuth has one short (2.1698(12)-2.300(3)
Å) and one long (2.245(2)-2.441(2) Å) Bi-Oµ bond distance.
Calixarene Bismuth Complexes. Crystal structures of
4-6 are illustrated in Figures 3-6, and selected bond lengths
and angles are listed in Tables 3 and 4. The structures of
4-6 are again very similar to those of other main group
Inorganic Chemistry, Vol. 47, No. 23, 2008 11151

Liu et al.
Table 6. Selected Bond Lengths (Å) and Angles (deg) of 11 and 12
11
12
Bi(1)-O(1)
Bi(1)-O(2)
Bi(1)-O(3)
Bi(2)-O(1′)
Bi(2)-O(2′)
Bi(2)-O(3′)
2.061(3)
2.098(3)
2.112(3)
2.069(3)
2.096(3)
2.100(3)
Bi(1)-O(2)
Bi(1)-O(1)
Bi(2)-O(3)
Bi(2)-O(4)
Bi(3)-O(6)
Bi(3)-O(5)
Bi(4)-O(7)
Bi(4)-O(8)
Bi(1)-Cl
2.151(3)
2.217(3)
2.158(3)
2.203(3)
2.161(3)
2.210(3)
2.164(3)
2.202(3)
Bi(3)-Cl
Bi(4)-Cl
Li(1)-O
Li(2)-O
Li(3)-O
Li(4)-O
Li(5)-O
Li(6)-O
Li(1)-C
Li(3)-C
2.5506(12)-3.0266(11)
2.5595(13)-2.9747(12)
1.889(9)-1.918(9)
1.938(9)-1.966(8)
1.912(9)-1.955(8)
1.923(9)-1.945(8)
1.975(11)-2.072(11)
2..093(10)-2.180(10)
2.722(9)-2.752(9)
2.787(9)-2.790(8)
O(1)-Bi(1)-O(2)
O(1)-Bi(1)-O(3)
O(2)-Bi(1)-O(3)
O(1′)-Bi(2)-O(2′)
O(1′)-Bi(2)-O(3′)
O(2′)-Bi(2)-O(3′)
Caryl-O-Bi
89.05(10)
91.15(10)
94.52(11)
87.83(11)
89.54(11)
94.05(11)
121.2(2)-128.6(2)
2.5413(13)-2.9864(12)
2.5580(12)-3.0079(11)
Bi(2)-Cl
O(2)-Bi(1)-O(1)
O(3)-Bi(2)-O(4)
O(5)-Bi(3)-O(6)
O(7)-Bi(4)-O(8)
88.03(11)
88.86(11)
86.72(11)
87.32(11)
Clbridge-Bi-Clbridge
Clbridge-Bi-Clbridge
Bi-Cl-Bi
103.46(3)-112.16(3)
82.54(3)-83.92(3)
94.90(4)-114.32(4)
124.5(2)-134.3(3)
Caryl-O-Bi
F5)3(C7H8)}2]·2C7H8,31 bismuth complexes of aminetris(phe-
noxide)s,32 [Bi8O4(ButC8)2] · 4C7H8,48 and [Bi(OSiBut-
Ph2)3]2.73 Asymmetric intramolecular bismuth-arene π
interactions have also been reported for the Bi(OCPh3)3
molecule.57 The Bi-Ar centroid distances are generally
determined by the acid-base properties of the donors and
the acceptors. In 4-6 the bismuth atoms are each coordinated
to the aromatic rings from their own ligands, which is
facilitated by the doubly flattened partial cone conformation
of the calixarene. The Bi-C distances and Bi · · · centroid
(aryl) distances in 4-6 (Table 6) are comparable with those
in the literature.30-32,48,57,74-76 The Bi · · ·Bi distances in 4-6
(3.8698(4)-3.917(5) Å) are much longer than those in the
polymetallic bismuth oxo aryloxide Bi8O4(ButC8)2 (3.6985(3),
3.6992(3), and 3.7670(3) Å)48 and the dimeric units of
Bi(OCH2CH2OCH3)3 (3.6426(4) Å)77 because of the rigidity
of the calix[4]arene backbone.
Table 7. Comparison of Bi-Clbridge Distances
Bi-Clbridge /Å
2.8421(11)-3.0266(12)
ref
12
this work
[TmBiCl(µ-Cl)]2
2.807(5)-3.009(5)
2.861(7)-3.020(7)
2.9325(13)-3.0020(12)
2.859(1)-3.074(13)
2.746(4)-2.763(3)
2.729(4)-2.852(4)
85
82
72
86
87
83
Bu4N[PhBiCl2Br][NMe4]2
[Bi2(OC6H3Me2-2,6)6(µ-Cl)2]
Mo(OMe)5(CH3CN)]Bi2Cl7
[Ph2BiCl]∞
[{(Me3Si)2CHBiCl2}2 ·Et2O]∞
The longer bond can be thought of as donation arising from
one metal aryloxide to a second metal center.30
The addition of a halide anion source provides a facile
method of preparing anionic bismuthate compounds because
of the Lewis acidity of bismuth(III).72 There are two kinds
of chlorine atoms in 4-6. One is the terminal chlorine atom
with a short Bi-Cl bond; the other is the bridging chlorine
atom between lithium and bismuth, which has a long Bi-Cl
bond distance. The Bi-Clterminal distances are in the range
of 2.5386(8)-2.6106(10) Å, which are comparable to those
in [Bi2Cl4(THF)2(µ-O-2,6-Me2C6H3)2] and [Bi2Cl4(THF)2(µ-
O-2,4,6-Me3C6H2)2].72 The Bi-Clbridge distances are in the
range of 2.7239(15)-2.7907(8) Å, which are similar to those
in oligomeric chlorobismuth(III) structures.10 The Cl-Bi-Cl
angles in 4-6 (87.54(3)-107.17(4) Å, Tables 1 and 2) vary
greatly, most likely because of different coordination envi-
ronments of the lithium cations connected to the bridging
chlorineatoms.TheBi-O-Biangles(114.17(9)-0116.07(8)°,
Tables 1 and 2) are close to each other, and similar to those
in [Bi[OCH(CF3)2]3(THF)2] (109.1(3)°),30,31 [Bi(OC6F5)2(µ-
OC6F5)Xn]2 · zY (X ) Y ) C7H8, n ) 1, z ) 1 or 2; X )
THF, Y ) C6H14, n ) 2, z ) 0 or 1) (112.1(3)-112.8(3)°),30
1, and 2 (114.21(7) and 114.02°). The average Bi-O-C
(aryl) angles (121° for 4a, 4b, 5, and 6) are in good
agreement with that in Bi(O-2,6-Me2C6H3)3 (123.4°).29
The lithium cations in 4a, 4b, and 6 associate with the
bismuth core by a chlorine bridge and additionally bind to
solvent. Only in 5 are the lithium cations separated from
the core structure, and their geometry can be described as
distorted tetrahedral.
The crystal structure of 11 is shown in Figure 7, and
selected bond lengths and angles are listed in Table 6. In
the crystal structure of 11 the asymmetric unit has two
independent molecules. Their bond distances and angles are
similar. The calix[4]arene moiety in 11 adopts a 1,2-alternate
conformation, and the tert-butoxide group faces away from
the cavity of the calix[4]arene. The Bi-O bond lengths fall
into the range of 2.061(3)-2.112(3) Å, typical for bis-
muth(III) aryloxides/alkoxides.29,31,32,48,74,78 The O(2)aryl
-
Bi-O(3)aryl bond angle (94.52(11)°) is slightly larger than
the Oaryl-Bi-Oalkyl bond angles (89.01(11) and 91.15(11)°)
because of the calix[4]arene backbone. The Bi-O-C (aryl)
angles (121.2(2)-122.8(2)°) are in agreement with those in
other bismuth aryloxides29,33 and calix[4]arene main group
element complexes.55,79-81 Two of the calixarene aryl rings
(74) Mansfeld, D.; Mehring, M.; Schurmann, M. Z. Anorg. Allg. Chem.
2004, 630, 1795–1797.
(75) Mehring, M.; Schurmann, M. Chem. Commun. 2001, 2354–2355.
(76) Breeze, S. R.; Wang, S. Angew. Chem., Int. Ed. Engl. 1993, 32, 589–
591.
(77) Massiani, M.-C.; Papiernik, R.; Hubert-Pfalzgraf, L. G.; Daran, J.-C.
Chem. Commun. 1990, 301–302.
(78) Mansfeld, D.; Mehring, M.; Schurmann, M. Angew. Chem., Int. Ed.
η6-Bismuth-arene π interactions have been observed
previously in mixed bismuth aryloxides, such as [{Bi(OC6-
Engl. 2005, 44, 245–249.
(79) Fan, M.; Zhang, H.; Lattman, M. Organometallics 1996, 15, 5216–
5219.
(72) Hodge, P.; James, S. C.; Norman, N. C.; Orpen, A. G. J. Chem. Soc.,
Dalton Trans. 1998, 4049–4054.
(73) Massiani, M.-C.; Papiernik, R.; Hubert-Pfalzgraf, L. G.; Daran, J.-C.
Polyhedron 1991, 10, 437–445.
(80) Shevchenko, I.; Zhang, H.; Lattman, M. Inorg. Chem. 1995, 34, 5405–
5409.
(81) Sood, P.; Zhang, H.; Lattman, M. Organometallics 2002, 21, 4442–
4447.
11152 Inorganic Chemistry, Vol. 47, No. 23, 2008

Bismuth(III) and Antimony(III) Calixarene Complexes
are puckered around the bismuth atom to enhance both η6
and η3 bismuth-arene π interactions. The ranges of Bi-C
distances and Bi · · · centroid (aryl) distances (Table 5) are
comparable with those in 4-6.
to three bridging chlorines, one terminal chlorine, and two
oxygen atoms of the phenolates. The apical sites are occupied
by either a bridging or a terminal chlorine, and the equatorial
plane consists of two cis oxygen atoms and two cis chlorine
atoms. The Bi-O (aryl) distances are in the range of
2.151(3)-2.217(3) Å, typical for bismuth aryloxide com-
plexes.29,31,32,48 The conformation of ButC8 can be described
as a slightly pinched cone, similar to that observed in our
polymetallic bismuth oxo aryloxide Bi8O4(ButC8)2.48
Irregular coordination polyhedra are observed for the
lithium cations. The lithium cations Li(5) and Li(6) are
separate from the core structure of 12 (see Figure 8). Li(5)
is five-coordinate with a distorted square-based pyramidal
geometry and Li(6) is six-coordinate with a distorted square-
based bipyramidal geometry. The lithium cations attached
to the core structure are coordinated to two oxygen atoms
from phenolates, one oxygen atom from solvent (THF or
DME), and one chlorine atom, and their coordination
geometry is distorted trigonal bipyramidal with the Cl atom
in the apical position.
The Li-O bond lengths differ depending on the coordina-
tion environment of the lithium cations. The shorter Li-O
bond lengths are observed for the lithium cations attached
to the core structure [Li(1)-O 1.889(9)-1.918(9) Å, Li(2)-O
1.938(9)-1.966(8) Å, Li(3)-O 1.912(9)-1.955(8) Å, and
Li(4)-O 1.923(9)-1.945(8) Å], similar to those found in
calix[4]arene alkali metal/molybdenum dioxo complexes
(1.860(11)-1.933(9) Å).37 The longer Li-O bond lengths
are found for the lithium cations that are away from the core
structure [Li(5)-O 1.975(11)-2.072(11) Å, and Li(6)-O
2..093(10)-2.180(10) Å].
The crystal structure of 12 is shown in Figure 8, and
selected bond lengths and angles are listed in Table 6. The
structure of 12 has a complex anion [ButC8(Bi(µ3-Cl)Cl)4(µ-
Cl)2 · 4Li · 3THF · DME]2-. Its length is about 2 nm. The
planar [Bi(1)Bi(2)Bi(3)Bi(4)] core bears the four terminal
chlorine atoms Cl(4), Cl(6), Cl(9), and Cl(10). These chlorine
atoms adopt a syn arrangement with respect to the plane
defined by four bismuth atoms and orient away from each
other. The Bi-Clterminal distances are in the range of
2.5413(13)-2.5595(13) Å, similar to those in [Bi2Cl4(THF)2(µ-
O-2,6-Me2C6H3)2](2.456(2)-2.585(2)Å)and[Bi2Cl4(THF)2(µ-
O-2,4,6-Me3C6H2)2] (2.4563(13)-2.5695(13) Å).72
Aryloxide groups can form strong bridging interactions
in bismuth(III) aryloxide/alkoxide complexes,72 and chlorine
bridges are also well established in oligomeric chlorobis-
muth(III) structures.82-84 In 12, each pair of bismuth atoms
is linked by chlorine bridges. Bi(1) and Bi(2) are linked
together by Cl(1) and Cl(2), and Bi(3) and Bi(4) are fused
together via Cl(7) and Cl(8). There is one chlorine bridge
Cl(5) for Bi(3) and Bi(2), and one chlorine bridge Cl(3) for
Bi(1) and Bi(4). Two bridging chlorine atoms Cl(1) and Cl(7)
are located on the inside of the cavity of calix[8]arene, as
well as their lithium cations Li(1) and Li(3). The rest of the
bridging chlorine atoms are outside the cavity and located
on the same side as the terminal chloride atoms. All bridging
chlorine atoms are asymmetric. The Bi-Clbridge distances are
in the range of 2.8421(11)-3.0266(12) Å, comparable to
those in the literature (Table 7).
Conclusion
The Clbridge-Bi-Clbridge angles in 12 are of two types,
larger angles with the range of 103.46(3)-112.16(3)° and
smaller angles with the range of 82.54(3)-83.92(3)°. The
smaller angles are the internal angles of two quadrangles
[Bi(1)Cl(1)Bi(2)Cl(2)] and [Bi(3)Cl(7)Bi(4)Cl(8)]. The
Bi-Clbridge-Bi angles (94.90(4)-114.32(4)) are consistent
with those in [{(Me3Si)2CHBiCl2}2 · Et2O]∞ (98.88(16)°).83
The O-Bi-O angles (88.03(3)-88.86(3)°) are close to the
idealized 90° angles for the equatorial plane in a square-
basedbipyramid.TheBi-O-C(aryl)angles(126.0(2)-134.3(3)°)
are somewhat larger than those in 4-6 (Tables 1 and 2) and
Bi(O-2,6-Me2C6H3)3 (123(4)°).29
We have developed a systematic procedure to synthesize
novel Bi(III) and Sb(III) calixarene complexes. Both anti-
mony and bismuth favor a 2:1 metal/calixarene ratio, forming
M2(µ-O)2 cores in partially flattened cone calixarenes, similar
to several other main group elements.49,51-55 To form 1:1
metal/calixarene complexes it is necessary to block two of
the calixarene phenol groups, preferably in 1,2 orientation.
The Lewis acidity of bismuth causes the association of
chloride anion to form anionic bismuth calixarene complexes,
as well as significant cation-π interactions with the calixarene
ring. The 2:1 bismuth/phenol stoichiometry has allowed the
controlled synthesis of the bismuth calix[8]arene complex,
which is again anionic because of chloride association, but
does not exhibit π-cation interactions.
Each bismuth atom in 12 resides in a distorted square-
based bipyramidal coordination environment being bonded
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M.; Hernandez, S.; Garcia, J. L. Z. Anorg. Allg. Chem. 2000, 626,
921–924.
Acknowledgment. We are grateful to the Welch Founda-
tion (Grant P-1459) and the National Science Foundation
(Grant CHE-133866) for research funding.
(83) Althaus, H.; Breunig, H. J.; Rosler, R.; Lork, E. Organometallics 1999,
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1992, 1967–1974.
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Supporting Information Available: X-ray crystallographic data
in CIF format and sample NMR spectra. This material is available
free of charge via the Internet at http://pubs.acs.org.
IC801445M
Inorganic Chemistry, Vol. 47, No. 23, 2008 11153