Bismuth aryloxides

Article abstract of DOI:10.1021/ic901134t

The synthesis and full characterization (mp, NMR, UV/vis, FTIR, and elemental analysis) of 13 bismuth aryloxides are reported. We have prepared bismuth aryloxides with alkyl, aryl, and allylic substituants on the aryl rings. Eleven of these bismuth arylox

Full text of DOI:10.1021/ic901134t

11002 Inorg. Chem. 2009, 48, 11002–11016
DOI: 10.1021/ic901134t
Bismuth Aryloxides
Xiaodi Kou,† Xiaoyu Wang,† Daniel Mendoza-Espinosa,† Lev N. Zakharov,‡ Arnold L. Rheingold,‡
William H. Watson,† Kimberly A. Brien,† L. Kasun Jayarathna,† and Tracy A. Hanna*,†
†Department of Chemistry, Texas Christian University, Box 298860, Fort Worth, Texas 76129, and
‡Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, m/c 0358,
La Jolla, California 92093-0358
Received June 15, 2009
The synthesis and full characterization (mp, NMR, UV/vis, FTIR, and elemental analysis) of 13 bismuth aryloxides are
reported. We have prepared bismuth aryloxides with alkyl, aryl, and allylic substituents on the aryl rings. Eleven of
these bismuth aryloxides have been characterized with single crystal X-ray diffraction methods. Bismuth-donor
interactions (donor = aryl, methoxy) are observed in several cases. Three unexpected bismuth oxo aryloxides (6c, 9c,
11c) were also isolated. Complex C77H102Bi4Br6O8 (6c) results from apparent C-H activation and Bi-C bond
formation as a sideproduct in the synthesis of Bi(O-2,6-iPr2-4-BrC6H2)3 (6). Cluster 9c has a Bi32O56 core, and cluster
C90H90Bi4Li2O12 (11c) is the second lithium bismuth oxo cluster reported to date.
I. Introduction
radioisotope therapy,14 and many other pharmaceutical
applications.13 The low toxicity of bismuth has led to its
use as a lead replacement in many materials.15 There is also
interest in the fundamental chemistry of this heavy main
group element, which frequently differs from the chemistry of
its lighter congeners.16-18
Our group has been interested for some time in the
chemistry of bismuth alkoxides,4,19-26 especially as models
for the Bi/Mo oxide SOHIO catalysts that are used for
propene/propane oxidation and ammoxidation.22 We re-
viewed current knowledge pertaining to the role of bismuth
in the SOHIO process and concluded that both its exact role
There has been a recent surge of interest in the chemistry of
bismuth, especially the chemistry of bismuth alkoxides.
Bismuth is an important component of oxide ion conduc-
tors,1 ferroelectric materials,2,3 catalysts,4-6 superconduc-
tors,7,8 and other advanced materials,9,10 and bismuth
alkoxides have been extolled as promising precursors for
such bismuth oxide-containing materials.10-12 Bismuth com-
pounds are used for treatment of gastrointestinal disorders,13
*To whom correspondence should be addressed. E-mail: t.hanna@
tcu.edu.
(1) Sammes, N. M.; Tompsett, G. A.; Nafe, H.; Aldinger, F. J. Eur.
Ceram. Soc. 1999, 19, 1801–1826.
(2) Vehkamaki, M.; Hatanpaa, T.; Ritala, M.; Leskela, M. J. Mater.
Chem. 2004, 14, 3191–3197.
(3) Park, B. H.; Kang, B. S.; Bu, S. D.; Noh, T. W.; Lee, J.; Jo, W. Nature
1999, 410, 682–684.
(4) Hanna, T. A. Coord. Chem. Rev. 2004, 248, 429–440.
(5) Leonard, N. M.; Wieland, L. C.; Mohan, R. S. Tetrahedron 2002, 58,
8373–8397.
(6) Liu, H.; Nakamura, R.; Nakato, Y. ChemPhysChem 2005, 6, 2499–
2502.
(7) Gunji, T.; Unno, M.; Arimitsu, K.; Abe, Y.; Long, N.; Bubendorfer,
A. Bull. Chem. Soc. Jpn. 2005, 78, 187–191.
(8) Pan, S. H.; Hudson, E. W.; Lang, K. M.; Eisaki, H.; Uchida, S.; Davis,
J. C. Nature 2000, 403, 746–750.
(9) Cabot, A.; Marsal, A.; Arbiol, J.; Morante, J. R. Sens. Actuators, B
2004, 99, 74–89.
(10) Mehring, M. Coord. Chem. Rev. 2007, 251, 974–1006.
(11) Williams, P. A.; Jones, A. C.; Crosbie, M. J.; Wright, P. J.; Bickley, J.
F.; Steiner, A.; Davies, H. O.; Leedham, T. J.; Critchlow, G. W. Chem. Vap.
Deposition 2001, 7, 205–209.
(12) Hubert-Pfalzgraf, L. G. Inorg. Chem. Commun. 2003, 6, 102–120.
(13) Briand, G. G.; Burford, N. Chem. Rev. 1999, 99, 2601–2657.
(14) Blower, P. J. Annu. Rep. Prog. Chem. Sect. A: Inorg. Chem. 2000, 96,
645–662.
(15) Sano, Y.; Satoh, H.; Chiba, M.; Okamoto, M.; Serizawa, K.;
Nakashima, H.; Omae, K. J. Occup. Health 2005, 47, 293–298.
(16) Whitmire, K. H. In Encyclopedia of Inorganic Chemistry; Wiley:
New York, 1994; Vol. 1, pp 280-291.
(17) Whitmire, K. H. In Encyclopedia of Inorganic Chemistry; Wiley:
New York, 1994; Vol. 1, pp 292-300.
(18) Burrows, A. D. Annu. Rep. Prog. Chem. Sect. A: Inorg. Chem. 2003,
99, 83–99.
(19) Hanna, T. A.; Keitany, G.; Ibarra, C.; Sommer, R. D.; Rheingold, A.
L. Polyhedron 2001, 20, 2451–2455.
(20) Liu, L.; Zakharov, L. N.; Golen, J. A.; Rheingold, A. L.; Hanna, T.
A. Inorg. Chem. 2008, 47, 11143–11153.
(21) Liu, L.; Zakharov, L. N.; Rheingold, A. L.; Hanna, T. A. Chem.
Commun. 2004, 1472–1473.
(22) Hanna, T. A.; Rieger, A. L.; Rieger, P. H.; Wang, X. Inorg. Chem.
2002, 41, 3590–3592.
(23) Mendoza Espinosa, D.; Hanna, T. A. Dalton Trans. 2009, 5211–5225.
(24) Mendoza Espinosa, D.; Rheingold, A. L.; Hanna, T. A. Dalton
Trans. 2009, 5226–5238.
(25) Mendoza Espinosa, D.; Hanna, T. A. Inorg. Chem. 2009, 48,
10312-10325.
(26) Mendoza Espinosa, D.; Hanna, T. A. Inorg. Chem. 2009, 48, 7452–
7456.
r
pubs.acs.org/IC
Published on Web 11/02/2009
2009 American Chemical Society

Article
Inorganic Chemistry, Vol. 48, No. 23, 2009 11003
and the mechanistic details remain controversial.4 It is
certainly involved in the initial activation of propene; how-
ever, its oxidation state over the course of this activation
remains a subject of discussion. We communicated our
observations of bismuth-oxygen bond homolysis in homo-
geneous bismuth aryloxide complexes, which supports the
intervention of the Bi(II) radical in the SOHIO system.22
The role of bismuth in later oxidation/ammoxidation steps
such as hydrogen abstraction is unclear,4 but there have now
been multiple reports of homogeneous complexes in which
bismuth appears to intramolecularly abstract hydrogens to
form new bismuth-carbon bonds.27,28 We noted a similar
reaction in our laboratories4 and herein will provide more
detailed information concerning the crystal structure of the
resulting ladder complex.
Though bismuth aryloxides appear to mimic both structural
and functional aspects of the bismuth active site in the SOHIO
system, very few bismuth aryloxides have been reported.29-33
Indeed, the entire field of bismuth alkoxide chemistry is rather
small, as was brought out in a recent review.10
Herein, we will describe the synthesis and characterization
of a series of bismuth aryloxides, as well as some unexpected
side products that were found along the way. These com-
plexes can be used as straightforward homogeneous model
systems for the bismuth site, with substituents on the aryl ring
that are easily adjusted to control their stability. Many of
these complexes will be used in future studies of Bi(II) radical
formation by Bi-O bond homolysis and hydrogen abstrac-
tion from propene-like substrates. These complexes may also
have utility as precursors for bismuth oxide materials.
Bismuth catecholates have been reported, but with limited
characterization.29,36 Whitmire et al. prepared the halide-
substituted Bi(OC6F5)3.30 More exotic bismuth aryloxides
include bismuth calixarenes20,21,23-26 and a tripodal bismuth
aryloxide that forms an inverted sandwich structure with
toluene as the π-donating ligand.32 Several bismuth oxo
aryloxide clusters have been reported along with the corre-
sponding bismuth aryloxides.10,37,38
III. Results and Discussion
We have synthesized and fully characterized 13 bismuth
aryloxides. They will be discussed in three sections. Bismuth
aryloxides with alkyl substituents include the following: Bi(O-
2,6-iPr2C6H3)3 2, Bi(O-2-tBuC6H4)3 3, Bi(O-2,4,6-tBu3C6H2)3
4, ClBi(O-2,4,6-tBu3C6H2)2 5, Bi(O-2,6-iPr2-4-BrC6H2)3 6,
Bi(O-2,6-iPr2-4-ClC6H2)3 7, and Bi[O-2,6-iPr2-4-(OCH3)-
C6H2]3 8. Bismuth aryloxides with aromatic substituents
include the following: Bi[O-2,6-(C6H5)2C6H3]3 9 and Bi[O-
2,6-(CH2C6H5)2C6H3]3 10. Bismuth aryloxides with allyl
substituents include the following: Bi[O-2-(CH2CHdCH2)-
C6H4]3 11, Bi[O-2-(CHdCHCH3)C6H4]3 12, [Bi[O-2-OCH3-
6-(CH2CHdCH2)C6H3]3]2 13, and [Bi[O-2-OCH3-4-(CH2-
CHdCH2)C6H3]3]2 14. We have also isolated three bismuth
oxo aryloxide clusters as side products from the reactions
to make the corresponding bismuth aryloxides. They are
{(ArO)2Bi(μ3-O)Bi(μ2-O-4-Br-2-iPr-6-[(CdCH2)CH2] C6H2-
1:2κ2O, 2κC}2 (Ar = 4-Br-2,6-iPr2C6H2) (C77H102Bi4Br6O8,
6c), Bi32O4(OH)4(O-2,6-Ph2C6H3)12 (C216H160Bi32O56, 9c),
and Li2Bi4(μ3-O)2[O-2-(CH2CHdCH2)C6H4]10 (C90H90-
Bi4Li2O12, 11c).
All bismuth tris-aryloxides in this paper were synthesized by
the exchange reaction between bismuth amide and the appro-
priate phenol (eq 2). Some were also synthesized by salt
metathesis (eq 1), to obtain the identical products. The exchange
reaction method was preferred because the products often
precipitate out from the reaction mixture, facilitating isolation.
The reaction time varies from 4 to 12 h. The workup is simple
filtration and washing, and yields ranged from 40 to 88%.
The key factor of these reactions is how to favor product
formation. The selection of suitable solvents can help to
precipitate out the products and drive the reaction to com-
pletion. For example, the reaction of 2,6-diisopropyl-4-
methoxyphenol and bismuth amide Bi[N(SiMe3)2]3 in pen-
tane led to a mixture of product and starting materials. In
hexanes, this reaction went smoothly with the precipitation of
the product after 1 day.
II. Background of Bismuth Aryloxides
The first crystallographically characterized bismuth aryl-
oxide, Bi(O-2,6-Me2C6H3)3 1, was structurally characterized
by Evans and co-workers in 1989.31 It was synthesized by salt
metathesis, according to eq 1.
BiCl3 þ 3MOAr
ð1Þ
f
BiðOArÞ3 þ 3MCl
M ¼Li,Na; Ar ¼aryl
An analogue, Bi(O-2,6-iPr2C6H3)3 2, was mentioned in
an article by Sauer et al. in 1990, but no characterization
data were supplied.34 Sauer et al. used the bismuth amide
35
Bi[N(SiMe3)2]3 as a precursor, to which they added the
appropriate phenol (eq 2). We have primarily used these
same two methods in order to synthesize our bismuth aryl-
oxides.
Both the electronic and steric properties of the phenols can
affect the reaction. An advantage of choosing bismuth
aryloxides as the model complexes is that it is easy to change
the properties of the phenols by changing the substituents on
the phenyl ring.
BiðNR2Þ3 þ 3HOAr
ð2Þ
f
BiðOArÞ3 þ 3HNR2
R ¼Me or SiMe3; Ar ¼aryl
(27) Roggan, S.; Limberg, C.; Ziemer, B.; Brandt, M. Angew. Chem. Int.
Ed. 2004, 43, 2846–2849.
(28) Roggan, S.; Schnakenburg, G.; Limberg, C.; Sandhofner, S.; Pritzkow,
H.; Ziemer, B. Chem.;Eur. J. 2005, 11, 225–234.
(29) Smith, G.; Reddy, A. N.; Byriel, K. A.; Kennard, C. H. L. Aust. J.
Chem. 1994, 47, 1413–1418.
(30) Jones, C. M.; Burkart, M. D.; Bachman, R. E.; Serra, D. L.; Hwu, S.-J.;
Whitmire, K. H. Inorg. Chem. 1993, 32, 5136–5144.
(31) Evans, W. J.; Hain, J. H., Jr; Ziller, J. W. Chem. Commun. 1989,
1628–1629.
(32) Turner, L. E.; Davidson, M. G.; Jones, M. D.; Ott, H.; Schulz, V. S.;
Wilson, P. J. Inorg. Chem. 2006, 45, 6123–6125.
(33) Brym, M.; Jones, C.; Junk, P. C. Main Group Chem. 2006, 5, 13–19.
(34) Sauer, N. N.; Garcia, E.; Ryan, R. R. Mater. Res. Soc. Symp. Proc.
1990, 180, 921–924.
The formation of the trisubstituted bismuth compounds
was confirmed spectroscopically. In the 1H NMR spectra of
the products, there is no OH peak and the remaining
resonances are shifted from those of the starting phenols.
We did not observe exchange of free phenol into bismuth
(35) Gynane, M. J. S.; Hudson, A.; Lappert, M. F.; Power, P. P.;
Goldwhite, H. J. Chem. Soc., Dalton Trans. 1980, 2428–2433.
(36) Guilhaume, N.; Postel, M. Heteroat. Chem. 1990, 1, 233–235.
(37) Whitmire, K. H.; Hoppe, S.; Sydora, O.; Jolas, J. L.; Jones, C. M.
Inorg. Chem. 2000, 39, 85–97.
(38) James, S. C.; Norman, N. C.; Orpen, A. G.; Quayle, M. J.; Weckenmann,
U. J. Chem. Soc., Dalton Trans. 1996, 4159–4161.

11004 Inorganic Chemistry, Vol. 48, No. 23, 2009
Kou et al.
aryloxides. The IR spectra of the bismuth compounds display
essentially the absorption bands of the ligands except for the
OH stretch (at ∼3500 cm-1). The UV/vis spectra show peaks
for the absorption from the phenyl rings of the phenoxy
ligands. When the ligands have substituents that can form a
conjugated system with the phenyl ring, the wavelengths of
the peaks become longer, as expected. Eight of the bismuth
aryloxides (2, 5, 6, 7, 9, 10, 13, 14) have also been character-
ized by single crystal X-ray diffractometry (vide infra).
A. Ligands with Alkyl Substituents. After repeating the
synthesis of Bi(OAr)3 1 (literature yield 80%),31 we
synthesized bismuth aryloxide 2 using either salt metath-
esis or alcohol exchange. Both methods were successful,
with alcohol exchange providing the higher yield of 69%.
We obtained X-ray quality crystals by crystallization in
THF at -35 °C, and the crystal structure is shown in
Figure 1. The structure is very similar to that of 1,31 with a
monomeric trigonal pyramidal geometry, Bi-O bond
Bi(O-2,6-iPr2C6H3)3 2 was heated, but only in trace
quantities. After heating for one week at 135 °C, only
20% decomposition of Bi(OAr)3 was observed. In the
decomposition products, we observed trace diphenoqui-
none, 10% of the corresponding diol, and 90% phenol.
A1. Para-Substituted 2,6-ditBu Ligands. In order to
determine the effect of changing electronics on the
bismuth-oxygen bond homolysis reaction, we attempted
to synthesize the Bi(OAr)3 complexes with tBu groups in the
ortho positions and various para substituents. In the cases
of HO-2,6-tBu2-4-RC6H2 where R = H, Br, Cl, OMe, or
NMe2 the Bi(OAr)3 complexes were neither isolated nor
observed at room temperature due to fast decomposition.
When the reactions of bismuth amide with corresponding
phenol were tried, there was no reaction at room tempera-
ture. If heated to 45 °C, decomposition of bismuth amide
was observed. In all cases, free phenol and uncharacterized
black solidwere decomposition products, while for R = Br,
diphenoquinone was also observed by 1H NMRand X-ray.
In the case of the para-tBu group, salt metathesis
of BiCl3 with LiO-2,4,6-tBu3C6H2 yielded both Bi(O-
2,4,6-tBu3C6H2)3 4 (the composition of 4 was inferred by
analogy to the other bismuth aryloxides; the compound
was not sufficiently stable for either X-ray or elemental
analysis) and Bi(O-2,4,6-tBu3C6H2)2Cl 5. To isolate 4, a
2:1 mixture of phenolate and BiCl3 was stirred at room
temperature for 1 h and, then, filtered and recrystallized at
-35 °C. When a 1:1 mixture of phenolate and BiCl3 was
stirred for 12 h at room temperature, only 5 was isolated.
Variation of either the stoichiometry or the reaction time
led to unsatisfactory results (either black solid or intract-
able mixtures). With the bismuth amide exchange method
(eq 2), there was no reaction at room temperature. Appar-
ently the trisubstituted complex 4 is less stable than the
disubstituted complex 5, but both are unstable in solution.
The decomposition of 5 again proceeds through Bi-O
bond homolysis to form the phenoxy radical, which was
directly observed by UV/vis and EPR spectroscopies.39
The •O-2,4,6-tBu3C6H2 radical is quite stable, and an
independent sample was also synthesized by literature
procedures39,40 to confirm its spectroscopic identification.
Recrystallization in pentane at -35 °C led to the isola-
tion of X-ray quality crystals of complex 5 (see Figure 1).
Again, the Bi-O bond distances and angles are in the
normal range. Table 1 summarizes the Bi-O bond dis-
tances and angles. The Bi-Cl bond length in 5 is 2.492(1)
˚
lengths of 2.119(3), 2.092(3), and 2.082(3) A, and
O-Bi-O bond angles of 94.06(7), 95.74(6), and
96.35(7)° (see Table 1 for comparisons). The small
O-Bi-O bond angles are typical of Bi(III) complexes
and have been discussed previously.19,31
We have found that the steric bulk of the ligand is a
primary determinant of its ability to form isolable Bi-
(OAr)3 complexes. The asymmetric ligand 2-tert-butyl-
phenol, for example, had similar size and similar
reactivity to the diisopropylphenol. Bi(OtBuC6H4)3 was
obtained in 88% yield. Attempts to make the unsubsti-
tuted analogue Bi(OPh)3 led to white insoluble material.
When we increased the bulkiness of the ligand, by
t
putting Bu groups in both ortho positions, the reaction
was very different. As described in our previous commu-
nication,22 we observed multiple color changes of the
reaction mixture (yellow, red, deep green with black
precipitate) and identified di-tert-butylphenol A, diphe-
noquinone B, and diol C as the organic products (eq 3).
˚
A and likely covalent in nature. In Limberg et al.’s
All diamagnetic products were observed by NMR, and
the radical anion D was observed by electron paramag-
netic resonance (EPR). Mass balance showed that 30% of
the ligands were converted to oxidation products. The
remainder was observed either as an insoluble black
precipitate, or else as a combination of black precipitate
and a mirror around the inside of the reaction vessel.
bimetallic compound [Cp2Mo(μ-OEt)2Bi(OEt)2Cl], the
terminal Bi-Cl bond is 2.918(4) A.41 Unlike the bismuth
˚
aryloxy halides of Norman and co-workers,42 Bi(OAr)2Cl
5 is neutral, monomeric, and tricoordinated. This is due to
steric bulk of the ligand; Sb(O-2,4,6-tBu3C6H2)Cl2 was
also reported to be monomeric.42
A2. Para-Substituted 2,6-di-iPr Ligands. Since the di-
tert-butylphenols led to unstable bismuth aryloxides, we
(39) Cook, C. D.; Fraser, M. J. Org. Chem. 1964, 29, 3716–3719.
(40) Forrester, A. R.; Hay, J. M.; Thomson, R. H. In Organic Chemistry
of Stable Free Radicals; Academic Press Inc.: Bristol, Great Britain, 1968; pp
281-341.
(41) Hunger, M.; Limberg, C.; Kircher, P. Organometallics 2000, 19,
1044–1050.
(42) Hodge, P.; James, S. C.; Norman, N. C.; Orpen, A. G. J. Chem. Soc.,
Dalton Trans. 1998, 4049–4054.
Analogous decomposition products (identified by com-
parison with authentic samples) were observed when

Article
Inorganic Chemistry, Vol. 48, No. 23, 2009 11005
Figure 1. Diagramofthe molecularstructuresof2, 5, 6, 7, 9, and 10, all monomericbismuth aryloxides. Thermalellipsoidsare atthe 30%probabilitylevel.
Hydrogen atoms have been omitted for clarity.
next prepared bismuth complexes with 2,6-diisopropyl-4-
bromophenol, 2,6-diisopropyl-4-chlorophenol, 2,6-diiso-
propylphenol, and 2,6-diisopropyl-4-methoxyphenol.
The phenols HO-2,6-iPr2-4-RC6H2 for R = H, Br,43
Cl,44 and OMe45,46 were either obtained commercially
(44) Kolka, A. J.; Napolitano, J. P.; Filbey, A. H.; Ecke, G. G. J. Org.
Chem. 1957, 22, 642–646.
(43) Wheatley, W. B.; Holdrege, C. T. J. Org. Chem. 1958, 23, 568–571.

11006 Inorganic Chemistry, Vol. 48, No. 23, 2009
Kou et al.
{(ArO)2Bi(μ3-O)Bi(μ2-O-4-Br-2-iPr-6-[(CdCH2)CH2]
C6H2-1:2κ2O, 2κC}2 (Ar = 4-Br-2,6-iPr2C6H2) 6c with
new Bi-C bonds formed by activation of isopropyl sub-
stituents of the aryl ligands. Single crystals of compound 6c
were obtained twice and checked by independent crystal-
lographers. However, only a few crystals were obtained
each time, and we have not yet succeeded in optimizing
conditions to increase the yield. Allylic contaminants were
not detected in the starting phenol, and attempts to
produce analogues of 6c using phenols with ortho-allylic
substituents were unsuccessful.
Figure 2. Diagram of the molecular structure of 6c (30% probability
ellipsoids). Hydrogen atoms have been omitted for clarity.
˚
Table 1. Comparison of Important Bond Lengths (A) and Bond Angles (deg)
The structure of 6c may be compared to that of the
ladder complex reported by Uchiyama and co-workers,47
in which Martin’s ligand (-C6H4C(CF3)2O-)48 provides
Bi-C and Bi-O bonds. Most bond lengths and angles
fall within normal parameters.
˚
compound
average Bi-O (aryloxy)/A
average O-Bi-O/(deg)
131
2
2.091(5)
2.09(2)
92(2)
95(2)
5
6
7
9
2.093(3)
2.065(9)
2.065(9)
2.11(1)
96(8)
94(3)
94(3)
86(2)
The most notable structural aspect of compound 6c is the
Bi4O6 central core, which exemplifies a structural motif found
in many bismuth oxo alkoxide clusters.20,21,24,25,37,49,50 The
central centrosymmetrical four membered ring is not planar;
the dihedral angle between the Bi(1)O(1)Bi(2) and Bi(1)O-
(2)Bi(2) planes is 11.9°. However, the central Bi4O6 core is
10
13
14
2.10(2)
2.140(4)
2.177(9)
91(8)
85.1(3)
88.55(78)
˚
(R = H) or synthesized by literature procedures. All
bismuth aryloxides Bi(O-2,6-iPr-4-RC6H2)3 (R = H 2,
Br 6, Cl 7, OMe 8) were stable at room temperature and
characterized by mp, elemental analysis, 1H and 13C
NMR, UV/vis, and IR spectroscopies. The complexes
were made by alcohol exchange for the amido group of
Bi[N(SiMe3)2]3 with isolated yields of 45-78%. The
crystal structures of 6 and 7 were determined (Figure 1)
and found to be analogous to the structures of 2 and Bi(O-
2,6-Me2C6H3)3.31 Selected bond angles and distances are
summarized in Table 1.
planar within 0.053 A. Therefore, although O(1) and O(1A)
˚
are slightly above and below (0.204(3) A) the average Bi4O6
plane, the central Bi4O6 core can be considered to be copla-
nar, rather than forming the more common twisted frame-
work. The terminal aryloxy bonds are perpendicular to
the Bi4O6 plane, with the rings on O(3) and O(4) being
mutually perpendicular. A similar planar structure was
observed in a set of Andrews Bi(OCH(CF3)2)3L3 (L = thf,
Et2O, or tmeda) complexes,50 as well as in the Bi2Mo2O6
core of our mixed-metal bismuth molybdenum calixarene
cluster.26
As the para substituent was changed from bromo to H,
Cl, and then methoxy, the precipitation of product (eq 2)
appeared to slow. Whereas the product precipitated from
solution after only 1 h in the para-bromo case, it took 24 h
to appear for R = OMe. This trend is probably due to a
combination of electronic and solubility effects.
A3. Isolation of C77H102Bi4Br6O8 6c;A Cluster with
New Bi-C Bonds. During the isolation of Bi(O-2,6-iPr2-4-
BrC6H3)3 6, an unexpected side product was obtained
(eq 4). Treatment of Bi[N(SiMe3)2]3 with 3 equiv of 2,6-
diisopropyl-4-bromophenol (HOAr) in pentane at
room temperature gave a yellow cloudy solution after
12 h. Bi(OAr)3 6 was isolated from this reaction mixture
as an air sensitive yellow powder. Upon filtering and
concentration of the reaction mixture, crystals of an
unexpected byproduct were also obtained from the
mother liquor. Figure 2 shows the crystal structure of
There are two types of bismuth atoms, Bi(1) and Bi(2). The
Bi(1) atom is five coordinate, and its coordination can be
described as a pentagonal pyramid with one empty equatorial
coordination site. Four oxygen atoms and a vacant coordina-
tion site are at equatorial positions, with one carbon in the
apical position. The angles of C(8)-Bi(1)-O(1), C(8)-Bi-
(1)-O(1A), C(8)-Bi(1)-O(2), and C(8)-Bi(1)-O(4A) are
88.91(16), 93.99(16), 83.14(15), and 91.90(15)°, respectively.
(45) Omura, K. Synthesis 1998, 1145–1148.
(46) Helfenbein, J.; Lartigue, C.; Noirault, E.; Azim, E.; Legailliard, J.;
Galmier, M. J.; Madelmont, J. C. J. Med. Chem. 2002, 45, 5806–5808.
(47) Uchiyama, Y.; Kano, N.; Kawashima, T. Organometallics 2001, 20,
2440–2442.
(48) Martin, J. C. Science 1983, 221, 509–514.
(49) Thurston, J. H.; Swenson, D. C.; Messerle, L. Chem. Commun. 2005,
4228–4230.
(50) Andrews, P. C.; Junk, P. C.; Nuzhnaya, I.; Spiccia, L. Dalton Trans.
2008, 2557–2568.

Article
Inorganic Chemistry, Vol. 48, No. 23, 2009 11007
Table 2. Examples of Bismuth-Centroid and Bi-C Distances in Bi-Arene Interactions
˚
˚
compound
shortest Bi-C distances (A)
bismuth-centroid distances (A)
ref
Bi(O-2,6-Ph2C6H3)3, 9
Bi(O-2,6-Bz2C6H3)3, 10
Bi(OCPh3)3
{N(OAr)3Bi}2(toluene)
[Bi(OC6F5)2(μ-OC6F5)(C7H8)]2
3.115, 3.096, 3.083
3.376, 3.373, 3.155
3.179, 3.157, 3.052
3.524
3.479, 3.466, 3.341
3.900, 3.146, 3.830
3.93, 3.84, 3.71
3.07
19
32
30
3.162
2.958
The Bi(2) atom is coordinated only to four oxygens. Three
Bi-O bonds are in the plane of the Bi4O6 core with angles of
68.12(12)-73.45(10)° between the bonds, and the fourth
Bi-O bond is almost perpendicular to this plane (O(3)-
Bi(2)-O(2), O(3)-Bi(2)-O(1), and O(3)-Bi(2)-O(4) are
91.23(11), 93.50(12), and 90.16(11)°, respectively).
empty coordination sites on bismuth. The shortest dis-
tances between the bismuth centers and the carbons on
˚
the substituent phenyl rings are 3.155 A and 3.083 A,
˚
respectively (Table 2). The shortest reported Bi-C dis-
tance for a Bi-arene π-interaction is 3.052 A,19,55 while a
˚
51
˚
typical Bi-C covalent bond distance is 2.266(5) A.
The chelate six-membered ring Bi(1)O(2)C(1)C(2)C-
(7)C(8) is in an approximate boat conformation. The
The Bi-arene interactions in compounds 9 and 10
are asymmetric. For bismuth-arene interactions reported
in literature (Table 2 and the Schmidbaur review53), the
distances between bismuth and the centroid of the ring are
˚
C(7)-C(9) double bond distance is 1.339(7) A, and the
1H NMR spectrum shows methylene peaks at 4.76 and
4.36 ppm. This double bond activates the hydrogen atoms
on the neighbor carbon C(8); therefore, the group of C(8),
C(7), and C(9) is similar to an allyl. A bismuth atom
connects to C(8) of this group with a typical Bi-C single
˚
in the range of 2.96-3.93 A. The shortest distances
between the bismuth centers and the centroids of the
˚
phenyl rings in compounds 9 and 10 (3.146 and 3.341 A,
respectively) are inside this range.
51
˚
bond length of 2.266(5) A.
B1. Isolation of Bi32O4(OH)4(O-2,6-Ph2C6H3)12 9c. In
the system of Bi(O-2,6-Ph2C6H3)3 9, an unexpected com-
pound 9c was obtained during product crystallization
(Figure 3). Compound 9c contains a centrosymmetrical
Bi32O56 cluster.
In the structure of 6c, there is one C(7)dC(9) double
bond, as well as a new bond between the bismuth atom
and the carbon atom. This new carbon skeleton originates
from the abstraction of three hydrogens from the former
isopropyl substituent. The formation of a Bi;C bond in
the product implicates bismuth as the active metal. Lim-
berg et al. attributed Bi(III) C;H activation in their
complexes to a proximity-induced effect;28 a similar effect
may be operative in our system. This result strengthens
the connection between propene activation in the SOHIO
process and the bismuth aryloxide model systems.
B. Ligands with Arene Substituents. In order to explore
the possibility of Bi-π-interactions,30,52,53 we incorporated
unsaturated ortho substituents onto the aryl rings. The
precursor 2,6-diphenylphenol was commercially available,
and the 2,6-dibenzylphenol was either purchased or synthe-
sized by base catalyzed aldol condensation, followed by
rearrangement (eq 5).45,54 Both base and acid have been used
to catalyze the condensation, but the base catalyzed reaction
has better yield. For the bismuth tris(2,6-diphenylphenolate)
9 and tris(2,6-dibenzylphenolate) 10, the isolated yields were
87% and 88%, respectively. Complex 9was recently reported
by Brym et al. using the metal exchange method, but with
lower yield and without elemental analysis.33
Several large bismuth oxide clusters have been re-
ported. Whitmire and co-workers described a series of
bismuth clusters obtained using C6F5OH as a ligand
precursor, of which the largest has a Bi9O20 core.37 Our
group reported bismuth calixarene complexes with
Bi8O18 cores.20,21,24 Mehring recently reported a series
of bimetallic sodium bismuth oxo clusters separated from
the reaction of BiCl3 and NaOSiMe3, of which the largest
is [Bi50Na2O64(OH)2(OSiMe3)22] 2C7H8 2H2O.56 The
3
3
Dikarev group more recently reported a large bismuth
oxido diketonate cluster with a Bi38O45 core,57 while the
Andrews group reported a bismuth oxido salicylate clus-
ter with a Bi38O44 core.58 The structures of these bismuth
oxo clusters can give insight into the mechanism of
bismuth oxide formation in solution.56
Compound 9c has a core-shell structure (Figure 3).
The metal oxide core consists of fused rings of bismuth
and oxygen atoms, while the organic shell is made up of 12
2,6-diphenylbenzene groups. The core and the shell are
linked by twelve oxygen atoms. Similar inorganic core-
organic shell structures were also found in Whitmire’s
bismuth phenolate clusters,37 Mehring’s bismuth siloxide
clusters,56 Dikarev’s bismuth diketonate clusters,57 and
our bismuth calixarene clusters.20,21,23,24 In a catalytic
system, such an inorganic core with a large number of Bi
atoms (32 in compound 9c) may potentially play the role
(54) Lin, T.-Y.; Cromwell, N. H.; Kingsbury, C. A. J. Heterocycl. Chem.
1985, 22, 21–24.
(55) Jones, C. M.; Burkart, M. D.; Whitmire, K. H. Angew. Chem. Int. Ed.
1992, 31, 451–452.
The crystal structures of compounds 9 and 10 are
shown in Figure 1. In both compounds, three of the
phenyl rings form a protective environment about the
(56) Mehring, M.; Mansfeld, D.; Paalasmaa, S.; Schurmann, M. Chem.;
Eur. J. 2006, 12, 1767–1781.
(57) Dikarev, E. V.; Zhang, H.; Li, B. Angew. Chem. Int. Ed. 2006, 45,
5448–5451.
(58) Andrews, P. C.; Deacon, G. B.; Forsyth, C. M.; Junk, P. C.; Kumar,
I.; Maguire, M. Angew. Chem., Int. Ed. 2006, 45, 5638–5642.
(51) Althaus, H.; Breunig, H. J.; Rosler, R.; Lork, E. Organometallics
1999, 18, 328–331.
(52) Breunig, H. J.; Haddad, N.; Lork, E.; Mehring, M.; Mugge, C.;
Nolde, C.; Rat, C. I.; Schurmann, M. Organometallics 2009, 28, 1202–1211.
(53) Schmidbaur, H.; Schier, A. Organometallics 2008, 27, 2361–2395.

11008 Inorganic Chemistry, Vol. 48, No. 23, 2009
Kou et al.
For the smaller two clusters (Mansfeld’s Bi22O2660 and
Bi32O56 9c), there are three layers, in an A, B, A0 pattern.
For the larger clusters (Dikarev’s57 and Andrews’58 Bi38),
there are four layers in an A, B, B0, A0 pattern. The
structural similarity throughout all of the clusters is
evident, with an interesting addition of a central oxygen
chain found only in the Dikarev structure57 (passing
through the center of the cluster, parallel to the bismuth
layers).
There is strong similarity between the “A” layers of all
four clusters (Figure 5), although distances vary
(emphasized by dashed lines for long Bi-O contacts).
Characteristic adjoining Bi4O4 ladders21,24,37,47,56 are
most clearly seen in the Dikarev A layer57 and 9c, while
the Andrews and Mansfeld structures include smaller
fragments of the similarly patterned layer.
Figure 6 shows the B layers of the four clusters. Again
there is structural similarity, especially between the two
Bi38 clusters.57,58 The “extra” oxygen may be seen in the
center polyhedron of the Dikarev structure.57 In the case
of the B layer, the Bi32 cluster 9c has a more open
framework, compared to the ordered array of Bi3O4
polyhedra shown in the other B layers. This may be
caused by the bulkiness of the diphenylphenolate ligands.
In all cases, chains of Bi2O2 diamonds are observed, but
again, the distances are quite variable.
Figure 3. View of the compound 9c. Bismuth atoms with different
coordination numbers are shown in different colors: CN = 3 in yellow,
CN = 4 in pink, CN = 5 in blue, CN = 6 in green.
of a solid Bi2O3 catalyst, while the organic shell might
improve the solubility in organic solvents and/or interac-
tions with organic reagents.
The phenyl rings in the shell have weak asymmetric
π-interactions with the bismuth atoms in the core structure.
These interactions are similar to those observed in Bi(O-
2,6-(benzyl)2C6H3)3 10, Bi(O-2,6-Ph2C6H3)3 9, and Bi-
(OCPh3)3.19 The average distances between the three clo-
sest carbon atoms and the corresponding bismuth atoms
The bismuth oxygen bonds in the core structure of 9c
˚
have bond lengths varying from 2.056(10) to 2.734(10) A.
˚
The terminal Bi-O bonds (average = 2.537 A) are
significantly longer than the Bi-O bonds in the monomer
of compound 4 (average = 2.105 A). The bismuth atoms
˚
˚
in compound 9c adopt coordination numbers of 3, 4, 5, or
6 (weak Bi-aryl interactions were neglected for all cases).
All of the coordination geometries are distorted from the
predicted VSEPR structures.
range from 3.30 A (average interaction of Bi(5) with C(31),
˚
C(35), and C(36)) to 3.74 A (average interaction of Bi(4)
with C(18), C(13), and C(14)) (Figure 3). They are con-
sistently shorter than the sum of the van der Waals radii
(4.00A for Bi-aromatic C).59 The orientations of the phenyl
˚
In compound 9c, most of the bismuth atoms have the
coordination number of 4 (Figure 3, in pink). There are 16
of them in total, and they have similar geometries. For
instance, Bi(7) is coordinated to O(9), O(10), O(12), and
O(13) with all the bond angles less than 109° (79.7(3),
80.3(3), 83.6(4), and 81.9(3)°). It may be interpreted as a
distorted trigonal bipyramidal structure with an empty
coordination site in the equatorial plane. Two phenyl
rings are oriented in favorable positions for π-interac-
tions with the bismuth at the empty coordination site. The
O-Bi-O bond angle between the two apical oxygen
atoms and the bismuth atom is 155.1(3)°. The equatorial
O-Bi-O bond angle is 82.0(6)°, significantly less than
120°. There are no reports of molecular four-coordinated
bismuth oxygen complexes, but there are reports of
organometallic bismuth complexes with similar distorted
trigonal bipyramidal structures.61
There are 12 bismuth atoms with the coordination
number of 5 in compound 9c (Figure 3, in blue). We will
take Bi(4) as an example to discuss them. Bi(4) adopts a
distorted square pyramidal structure with bond angles of
84.0(3), 71.7(3), 102.2(3), and 95.4(3)° in the basal plane.
The bond angles between the apical oxygen atom, the
bismuth atom, and the four basal oxygen atoms are
87.1(3), 83.1(3), 74.8(3), and 78.5(3)°, respectively. Again,
the empty site on the bismuth is well-shielded by phenyl
substituents vary over a rangefrom mutually perpendicular
to almost parallel. The π-interactions between the bismuth
atoms in the core and the phenyl rings in the shell provide a
well-protected core when compared to other bismuth oxo
clusters with alkoxide or siloxide ligands.56
Mehring describes a number of bismuth oxide clusters
as based on a Bi6O82þ structural unit, combining to build
up progressively larger clusters.56 We can use a similar
method to describe our cluster 9c, but we would find
many distortions in the Bi6 octahedra, as well as many
missing O bridges. This difference may be due to the
bulkiness of the diphenylphenolate ligand shell.
Instead, we will compare the layers that are formed in
the core structure of compound 9c (see Figure 4) to
those of three clusters reported in recent years. These com-
t
pounds are the [Bi22O26(OSiMe2 Bu)14] cluster repor-
ted by Mansfeld et al.,60 the [Bi38O45(hfac)24] cluster
reported by Dikarev et al.,57 and the [Bi38O44(Hsal)26-
(Me2CO)16(H2O)2] 4Me2CO cluster reported by Andrews
3
et al.58 Despite the differences between the silanolate,
hexafluoroacetylacetonate, salicylate, and 2,6-diphenyl-
phenolate ligand environments, the similarities between
the four bismuth oxide cores are striking.
(59) Bondi, A. J. Phys. Chem. 1964, 68, 441–451.
(60) Mansfeld, D.; Mehring, M.; Schurmann, M. Angew. Chem. Int. Ed.
2005, 44, 245–249.
(61) Matano, Y.; Suzuki, H. Bull. Chem. Soc. Jpn. 1996, 69, 2673–2681.

Article
Inorganic Chemistry, Vol. 48, No. 23, 2009 11009
Figure 4. Core structure of compound 9c.
Figure 5. A layers for clusters [Bi22O26(OSiMe2 Bu)14],60 [Bi38O45(hfac)24],57 [Bi38O44(Hsal)26(Me2CO)16(H2O)2] 4Me2CO,58 and Bi32O4(OH)4(O-2,6-
t
3
Ph2C6H3)12 9c.

11010 Inorganic Chemistry, Vol. 48, No. 23, 2009
Kou et al.
Figure 6. B layers for clusters [Bi22O26(OSiMe2 Bu)14],60 [Bi38O45(hfac)24],57 [Bi38O44(Hsal)26(Me2CO)16(H2O)2] 4Me2CO,58 and Bi32O4(OH)4(O-2,6-
t
3
Ph2C6H3)12 9c.
rings in the organic shell. In the literature, five-coordinate
bismuth-oxygen complexes are generally described as
square pyramidal structures or trigonal bipyramidal struc-
tures.37,62,63 Five-coordinate bismuth atoms in R-Bi2O3
also have square pyramidal structures.64
in the basal plane are 99.2(3), 63.7(3), 68.7(3), 66.6(3), and
66.4(3)°. The bond angles between the apical oxygen atom,
the bismuthatom, and the oxygen atomsonthe basal plane
are 87.7(3), 88.8(3), 89.1(3), 96.2(3), and 72.1(3)°.
Finally, as shown in Figure 4, compound 9c has unique
oxygen atoms O(23) and O(28). The positions of the
corresponding H atoms were not found from the F-maps.
To provide the correct charge balance for 9c, an additional
four hydrogens should be in the core of the compound. We
suggest that the two O atoms (O(23) and O(28)) and their
symmetrical equivalents are OH groups, so that the for-
mula of 9c is (C18H13O)12Bi32O40(OH)4. The positions and
structural functions for these two O atoms are different
from those for the other O atoms in the Bi32O56 core. The
O(28) atom is terminal, and the O(23) atom is the only μ2
bridge between two bismuth atoms in the central core; the
other O atoms not bonded to ligands are μ3 bridges
between bismuth atoms.
There are four bismuth atoms with the coordination
number of 6 in compound 9c (Figure 3, in green). For
example, in Bi(11), the six oxygen-bound ligands define a
distorted pentagonal pyramid with six Bi-O bonds of
2.667(10), 2.654(8), 2.454(10), 2.346(9), 2.213(9), and
˚
2.116(8) A, respectively. Whitmire defines the coordina-
tion environment of the bismuth atoms in NaBi4(μ3-OR)2-
(OR)9(THF)2 as composed of six oxygen atoms and one
lone pair of electrons in a distorted pentagonal bipyrami-
dal array.37 For Bi(11), the structure may also be described
as distorted pentagonal pyramidal, with arene rings shield-
ing the empty coordination site. The O-Bi-O bondangles
˚
(62) Massiani, M.-C.; Papiernik, R.; Hubert-Pfalzgraf, L. G.; Daran,
J.-C. Polyhedron 1991, 10, 437–445.
(63) Sundvall, B. Inorg. Chem. 1983, 22, 1906–1912.
(64) Malmros, G. Acta Chem. Scand. 1970, 24, 384–396.
The Bi(2), a O(28) distance, 2.137(10) A, is too short for
a coordinated H2O molecule (literature values of 2.61-
63
˚
(1)-3.00(1) A ). This distance is slightly shorter than

Article
Inorganic Chemistry, Vol. 48, No. 23, 2009 11011
the methoxy groups chelate to bismuth atoms with Bi-O
distances of 2.664(3) and 2.706(3) A. The third methoxy
group bridges to a bismuth atom in the neighboring dimer,
˚
˚
with a distance of 2.933(15) A. In complex 13, all three
methoxy groups have chelating interactions with distances
˚
of 2.772(15), 2.766(16), and 2.785(15) A. Presumably the
large allyl groups in the ortho positions deter formation of a
polymeric chain. The structure of 13 is similar to that of
[Bi(OC6F5)3(tol)2]2 reported by Whitmire et al.30,55 The
Bi-O distances of the phenoxide bridges for compound 13
˚
are2.167(3) and2.608(11) A, and those of compound 14are
˚
2.183(3) and 2.636(3) A. They are comparable to Bi-O
distances in the Whitmire complex.30,55
C1. Isolation of Li2Bi4(μ3-O)2[O-2-(CH2CHdCH2)-
C6H4]10 11c;A Side Product with Lithium Ions. In the
reactionof2-allylphenol and bismuthamide, inaddition to
thebismutharyloxide11, asideproductwasobtainedfrom
the reaction mixture in low yield (not measured). Complex
11c was found to be a lithium bismuth oxo cluster Li2Bi4-
(μ3-O)2[O-2-(CH2CHdCH2)C6H4]10 (Figure 9). The core
geometry is essentially the same as that of Na2Bi4(μ3-O)2-
(OC6F5)10(THF)2, reported by Whitmire et al. in 2000.37
Mehring recently reported the first metal-oxo cluster con-
taining lithium and bismuth.67 The Li;O distances in 11c
Figure 7. Diagram of the molecular structure of 13, a bismuth aryloxide
with dimer geometry. Thermal ellipsoids are at the 30% probability level.
Hydrogen atoms have been omitted for clarity.
that expected for a terminal OH group (literature values
˚
˚
are 1.915(5) and 2.025(5) A, which are comparable to Li;
63
of 2.29(1)-2.48(1) A ), but not sufficiently short to
O distances in Mehring’s complex. The core structure of
complex 11c contains the same Bi4O6 subunit as 6c, a
common theme in Bi oxo compounds.20,21,23-26,37,49 The
lithium ion probably comes from LiCl impurity in the
bismuth amide starting material. Direct combination of
Bi(OAr)3 and LiOAr did not lead to formation of 11c.
D. Stability of Bismuth Aryloxides. Three stability tests
were performed on the 13 bismuth aryloxides (2-14):
shelf life, photolysis, and thermal stability monitored by
1H NMR. All 13 bismuth aryloxides showed no change in
consider it a BidO double bond (terminal oxo groups
have not been reported on bismuth oxo clusters,65 and a
terminal oxo group would also not be consistent with a
Bi(III) oxidation state). The bridging Bi(μ2-OH)Bi group
in [Ar2Bi(OH)Br]2 (Ar2 = 2,6-Mes2-4-tBuC6H2) contains
similar Bi;O distances of 2.553(6) and 2.138(6) A.52 The
˚
O(23);Bi(4) and O(23);Bi(14) distances in Bi(4);
˚
2
O(23);Bi(14) μ bridges (2.376(9) and 2.339(9) A, re-
spectively) are longer than the typical Bi;O distances in
Bi(μ2-O)Bi bridges but close to Bi;O distances (2.390
1
their H NMR spectra after being in a sealed ampule in
their solid form in the glovebox for 1 month. All com-
pounds were also stable to photolysis in CD3CN solution
2
˚
and 2.485 A) found for a Bi(μ -OH)Bi bridge in
C45H141Bi10Na5O28Si15 1.5C7H8.66
3
C. Ligands with Allylic Substituents. The apparent C;H
activation process described in section A3 occurred in very
small yields, but may be encouraged by the presence of active
allylic hydrogens in proximity to the bismuth center. Such
ligands may also be viewed as models of the propene
substrate that is activated in the SOHIO process.4 Accord-
ingly, we have synthesized a selection of bismuth aryloxides
containing allylic groups in various positions: Bi[O-2-
(CH2CHdCH2)C6H4]3 11, Bi[O-2-(CHdCHCH3)C6H4]3
12, [Bi[O-2-OCH3-6-(CH2CHdCH2)C6H3]3]2 13, and
[Bi[O-2-OCH3-4-(CH2CHdCH2)C6H3]3]2 14, with isolated
yields of 73-88%.
1
(monitored by H NMR) when irradiated for 10 min,
with the exception of Bi(O-2,6-iPr2-4-BrC6H2)3 (6), which
decomposed to 3,3,’5,50-tetra-iso-propyldiphenoquinone.
The same diphenoquinone is obtained upon photolysis of
4-bromo-2,6-diisopropylphenol.
Thermal decomposition in C6D6 was studied using 1H
NMR. All compounds were stable for up to 3 days at
45 °C. The decomposition temperature of each bismuth
aryloxide is shown in Table 3. In all cases the major
identifiable product was the corresponding phenol.
Bi(O-2,6-iPr2-4-BrC6H2)3 (6) decomposed to the corre-
sponding biphenol byproduct, 3,30,5,50-tetra-iso-propyl-
biphenol, as well as phenol when heated at 95 °C for
3 days. The biphenol product is consistent with the
formation of phenoxy radical during decomposition.22
We did not observe deuterium incorporation into phe-
nolic products.
We have generally found that the alcohol exchange
reaction with Bi[N(SiMe3)2]3 (eq 2) is the most convenient
method to prepare these bismuth aryloxides (see section A).
The starting phenols are commercially available.
Crystal structures of compounds 13 (Figure 7) and 14
(Figure 8) do not show any significant Bi-allyl interac-
tions. Although most of the bismuth aryloxides reported
here are monomeric, Bi(OAr)3 13 is a dimer bridged by
phenolate oxygen atoms, and 14 is a polymer chain com-
posed of phenolate-bridged dimers. In complex 14, two of
IV. Conclusions
We have described the systematic synthesis and character-
ization of a large number of bismuth aryloxides. Ring sub-
stituents include alkyl, aromatic, allyl, ether, amide, and
(65) Hoppe, S.; Whitmire, K. H. Organometallics 1998, 17, 1347–1354.
(66) Mehring, M.; Paalasmaa, S.; Schurmann, M. Eur. J. Inorg. Chem.
2005, 4891–4901.
(67) Mehring, M.; Mansfeld, D.; Costisella, B.; Schurmann, M. Eur. J.
Inorg. Chem. 2006, 735–739.

11012 Inorganic Chemistry, Vol. 48, No. 23, 2009
Kou et al.
Figure 8. Diagram of the molecular structure of 14, a bismuth aryloxide with polymer chain geometry. Thermal ellipsoids are at the 30% probability level.
Hydrogen atoms have been omitted for clarity.
tuent and a large bismuth oxo cluster presumably formed by
microhydrolysis. The characteristic Bi4O4 ladder structural
motif is seen in several of our clusters. Additionally, it can be
seen, from our work and that of others, that bismuth oxide
core-shell compounds tend to converge toward very similar
inorganic core structures irrespective of the nature of the
organic ligand. Others56 have compared the core structure
with that of solid bismuth oxides.
V. Experimental Section
General. All manipulations were performed inside a glovebox
under nitrogen atmosphere. 2-tert-Butylphenol, 2,6-diphenyl-
phenol, 2-allylphenol, 2-propenylphenol, o-eugenol, eugenol,
and 2,6-diisopropylphenol were purchased from Aldrich and
ꢀ
˚
stored in the glovebox over 3 A molecular sieves. Bismuth
chloride was purchased from Strem and recrystallized from
anhydrous ether. Bi[(N(SiMe3)2)]3,35 2,6-diisopropyl-4-bromo-
phenol,43 and 2,6-diisopropyl-4-chlorophenol44 were synthe-
sized as reported in the literature. THF was freshly distilled
from Na/benzophenone, and benzene was filtered through
activated alumina and Cu-based oxygen absorbent as described
by Grubbs et al.68 Anhydrous pentane and diethyl ether were
purchased from Aldrich. All these solvents were stored inside
˚
the glovebox over 4 A molecular sieves for at least 48 h before
use. NMR solvents (C6D6 and CDCl3) were degassed and dried
with CaH2.
Figure 9. Crystal structure of 11c (30% probability ellipsoids). H atoms
are omitted for clarity.
The melting points of the compounds were observed in sealed
capillary tubes on a Mel-Temp apparatus (Laboratory Devices,
Cambridge, MA). 1H and 13C NMR spectra were recorded on a
Varian Mercury Plus 300 MHz spectrometer. IR spectra were
obtained with an Infinity Gold FTIR spectrometer. UV/vis
spectra were recorded on an Agilent 8453 UV/Visible spectro-
photometer. Filtration was done with a medium pore sintered
glass frit. The yields reported are from pure isolated products.
Elemental analyses were performed by Atlantic Microlabs, Inc.
2,6-Dibenzylphenol was either purchased from Frinton La-
boratories, Inc., or synthesized in two steps. 2,6-dibenzylidenecy-
clohexanone was synthesized by an aldol condensation reaction
between cyclohexanone and benzaldehyde.54 Rearrangement of
the isolated product over Pd/C formed 2,6-dibenzylphenol.69
halogen groups. Their stabilities, spectroscopic, and structural
properties were compared. Most Bi(OAr)3 complexes are
monomeric, with similar structures about the bismuth centers.
These complexes serve as models for oxidation/ammoxidation
catalysis,4 models for bismuth oxide formation by hydrolytic
processes,12 and potential materials precursors.10,56
Bi-O bond homolysis of sterically crowded complexes
leads to the formation of phenoxy radicals in direct analogy
to the Bi-O bond homolysis proposed to intervene in the
rate-determining step of the SOHIO oxidation and ammox-
idation of propene.22
(68) Pangborn, A. B.; Giardello, M. A.; Grubbs, R. H.; Rosen, R. K.;
Timmers, F. J. Organometallics 1996, 15, 1518–1520.
(69) Horning, E. C. J. Org. Chem. 1945, 10, 263–265.
Interesting side products include a Bi-O ladder complex
i
formed by hydrogen abstraction from an Pr ligand substi-

Article
Inorganic Chemistry, Vol. 48, No. 23, 2009 11013
Table 3. Decomposition Temperatures of Bismuth Aryloxides in C6D6
a Decomposition to phenol þ 3,305,50-tetra-iso-propylbiphenol was observed.
The product was formed in 48% overall yield and was confirmed
sample was then left at room temperature for 3 days, then heated
in an isotemp oil bath to 45, 75, 95 and 135 °C for 3 days
each. Once decomposition occurred, the sample was no longer
heated.
1
by comparison of its H and 13C NMR spectra with the litera-
ture.70
2,6-Diisopropyl-4-methoxyphenol was synthesized with a
three-step procedure. First, 2,6-diisopropylphenol was oxidized
to 2,6-diisopropyl-p-benzoquinone with PbO2.45 Second, 2,6-
diisopropyl-p-benzoquinone was reduced to 2,6-bis(1-methyl-
ethyl)-1,4-benzenediol with Zn powder.46 Third, 2,6-bis(1-
methylethyl)-1,4-benzenediol was methylated with dimethyl
sulfate under basic conditions.71 The overall yield is 20% and
All compounds were stable when placed in a glass ampule,
sealed under vacuum, and placed in the glovebox for 1 month.
Bi(O-2,6-iPr2C6H3)3 (2). A solution of 2,6-diisopropylphenol
(1.05 g, 5.93 mmol) in 10 mL of THF was added to a solution of
Bi[(N(SiMe3)2)]3 (1.37 g, 1.98 mmol) in 10 mL of THF. The
yellow solution was stirred overnight. The solvent was then
removed under vacuum to obtain yellow powder, which was
dissolved in pentane. The solution was filtered and kept at
-35 °C to produce a yellow precipitate. The supernatant was
decanted and the solid dried in vacuo to produce 1.015 g of 2
(69% yield). Yellow rod crystals (0.30 ꢀ 0.08 ꢀ 0.08 mm3) of 2
were obtained at -35 °C from a concentrated THF solution for
X-ray analysis. mp: 165-166 °C (melt and dec). 1H NMR
(C6D6): δ (ppm) 7.05 (d, 6H, J = 8 Hz, ArH), 6.63 (t, 3H, J =
8 Hz, ArH), 3.69 (septet, 6H, J = 7 Hz, CHMe2), 1.12 (d, 36H,
J = 7 Hz, CH3). 13C NMR (C6D6): δ (ppm) 154.4 (C-OBi),
141.2, 122.8 (aromatic), 121.9 (C-iPr), 27.7 (CH(CH3)2), 24.8
(CH(CH3)2). IR (C6H6): 3086, 3007, 1974, 1945, 1801, 1474,
1422, 1318, 1179, 865, 758, 684, 659 cm-1. UV/vis (C6H6)
1
the product was confirmed by comparison of its H and 13C
NMR spectra with the literature.71
Photolysis was performed using in a Rayonet photochemical
reactor manufactured by The Southern New England Ultravio-
let Company. A 10 mg portion of each Bi(OAr)3 was placed in a
quartz NMR tube, and 0.6 mL CD3CN was added. The tube
was placed in the photochemical reactor for 10 min. All com-
pounds showed no change in the NMR spectrum with the
exception of Bi(O-2,6-iPr2-4-BrC6H2)3 (6).
Solution decomposition of each compound was studied using
1H NMR spectroscopy. A 10 mg portion of each Bi(OAr)3 was
sealed under vacuum in an NMR tube with 0.6 mL C6D6. The
λ
max/nm (ε/dm3 mol-1 cm-1): 349 (7000). Elemental analysis
(70) Mukawa, T.; Inoue, Y.; Shiraishi, S. Bull. Chem. Soc. Jpn. 1999, 72,
gave unsatisfactory results, so a high resolution mass spectrum
was obtained. HRMS (CI) m/e calcd for C36H51O3Bi: 740.3642
(Mþ). Found: 740.3647 (Mþ).
2549–2556.
(71) Petranek, J.; Pilar, J. Collect. Czech. Chem. Commun. 1970, 35, 830–
837.

11014 Inorganic Chemistry, Vol. 48, No. 23, 2009
Kou et al.
Thermolysis of Bi(O-2,6-iPr2C6H3)3 (2). An 11 mg portion
of Bi(O-2,6-iPr2C6H3)3 (0.015 mmol) and 8 mg of Ph3CH (0.033
mmol, as internal standard) were dissolved in 2 mL C6D6, and a
yellow solution was obtained. The yellow solution was added to
an NMR tube, and then, the tube was sealed under vacuum. The
tube was left in the 135 °C oil bath for 1 week. The weight
percentage of the decomposition products was calculated by the
(C-tBu), 128.8 (C-tBu), 121.7 (aromatic), 35.6 (ortho-C(CH3)3),
34.2 (para-C(CH3)3), 34.0 (ortho-C(CH3)3), 32.5 (para-C-
(CH3)3). IR (C6H6): 3624, 3066, 2953, 2863, 1531, 1495, 1252,
1085, 1061, 998, 799, 687, 631 cm-1. UV/vis (C6H6) λmax/nm
(ε/dm3 mol-1 cm-1): 285 (4890), 397 (2000). Anal. calcd. for
BiO2C36H58Cl: C, 56.35; H, 7.62. Found: C, 56.27; H, 7.57.
Compound 5 was stable at 75 °C in C6D6 solution for 3 days.
Decomposition to the corresponding phenol occurred after
heating the solution to 95 °C for 3 days.
1
comparison of the integration of the peaks in H NMR. The
authentic sample of diphenoquinone was synthesized by the
oxidation of the 2,6-diisopropylphenol with PbO2 in acetic acid,
and the biphenol (3,30,5,50-tetra-iso-propylbiphenol) was ob-
tained by the reduction of the diphenoquinone with Na2S2O4 in
ethanol.46
Bi(O-2,6-iPr2-4-BrC6H2)3 (6). A solution of 2,6-diisopropyl-
4-bromophenol (0.39 g, 1.5 mmol) in 10 mL of pentane was
added to a solution of Bi[(N(SiMe3)2)]3 (0.35 g, 0.51 mmol) in
5 mL of pentane. Yellow precipitate was formed after 4 h. The
suspension was stirred for another 8 h. The precipitate was
filtered out and washed with pentane (2 ꢀ 2 mL) and dried under
vacuum to obtain a yellow powder (0.33 g, 68% yield). Yellow
block crystals (0.54 ꢀ 0.46 ꢀ 0.28 mm3) of 6 were obtained at
-35 °C from a concentrated pentane solution for X-ray analysis.
mp: 130 - 132 °C (melt and dec). 1H NMR (C6D6): δ (ppm) 7.39
(s, 6H, ArH), 3.17 (septet, 6H, J = 7 Hz, CHMe2), 1.00 (d, 36H,
J = 7 Hz, Me). 13C NMR (C6D6): δ (ppm) 151.1 (C-OBi), 143.0
(C-Br), 126.0 (aromatic), 116.3 (C-iPr), 27.8 (CH(CH3)2), 23.7
(CH(CH3)2). IR (C6H6): 3083, 3036, 2960, 1963, 1824, 1483,
1422, 1318, 1258, 1179, 1094, 803, 712, 678 cm-1. UV/vis (C6H6)
Bi(O-2-tBuC6H4)3 (3). Asolutionof2-tert-butylphenol (0.45 g,
3.0 mmol) in 10 mL of pentane was added to a solution of
Bi[(N(SiMe3)2)]3 (0.69 g, 1.0 mmol) in 10 mL of pentane. The
yellow solution obtained was allowed to stir overnight. Solvent
was then removed under vacuum, and the solid produced was
washed with pentane (2 ꢀ 3 mL) and dried under vacuum to
1
obtain a yellow solid (0.55 g, 84% yield). mp: 125 °C (dec). H
NMR (C6D6): δ (ppm) 7.52 (d, 3H, J = 8 Hz, ArH), 7.05 (t, 3H,
J = 8 Hz, ArH), 6.95 (d, 3H, J = 8 Hz, ArH), 6.83 (t, 3H, J =
8 Hz, ArH), 1.54 (s, 27H, tBu). 13C NMR (C6D6): δ (ppm) 158.1
(C-O), 142.2 (C-tBu), 127.7, 128.8, 121.1, 119.8 (aromatic
carbons), 34.9 (C(CH3)3), 30.3 (C(CH3)3). IR (C6H6): 3072,
3044, 1959, 1815, 1478, 1437, 1213, 1035, 664, 460 cm-1. UV/vis
(C6H6) λmax/nm (ε/dm3 mol-1 cm-1): 277 (2104), 322 (703). Anal.
calcd. for BiO3C30H39: C, 54.88; H, 5.99. Found: C, 54.72; H, 6.00.
Compound 3 was stable after heating for 3 days at 75 °C. When
heated at 95 °C for 3 days, most of the compound had decom-
posed to the corresponding phenol. Additional heating at 135 °C
for 3 days showed only a small increase in phenol. The remaining
bismuth product continued to be stable with no change in the
NMR when the NMR tube was exposed to air for 5 min. After
12 h, the NMR showed only the phenol product.
λ
max/nm (ε/dm3 mol-1 cm-1): 277 (1497), 345 (395). Anal. calcd.
for BiO3C36H48Br3: C, 44.24; H, 4.95. Found: C, 44.48; H, 5.06.
Compound 6 was stable at 75 °C in C6D6 solution for 3 days.
Decomposition to phenol and 3,30,5,50-tetra-iso-propylbiphenol
(approximately 9:1 ratio) occurred after heating the solution to
95 °C for 3 days. The biphenol was identified by comparison to
an authentic sample.46
By slow evaporation of the filtrate solution at -35 °C, light
yellow block crystals (0.30 ꢀ 0.20 ꢀ 0.10 mm3) with the bismuth
oxide cluster structure (6c) were obtained twice; however, the
yield is quite low (not measured, <5%).
Bi(O-2,6-iPr2-4-ClC6H2)3 (7). A solution of 2,6-diisopropyl-
4-chlorophenol (0.32 g, 1.5 mmol) in 10 mL of hexane was added
to a solution of Bi[(N(SiMe3)2)]3 (0.35 g, 0.51 mmol) in 5 mL of
hexane. Yellow precipitate formed after 4 h. The suspension was
stirred for another 8 h. The precipitate was filtered out and
washed with pentane (2 ꢀ 2 mL) and dried under vacuum to
obtain yellow powder (0.23 g, 55% yield). Yellow prismatic
crystals (0.28 ꢀ 0.17 ꢀ 0.13 mm3) of 7 were obtained at -35 °C
from a concentrated ether solution for X-ray analysis. mp: 163 -
Bi(O-2,4,6-tBu3C6H2)3 (4). A suspension of the lithium salt of
2,4,6-tri-tert-butylphenol (0.130 g, 0.484 mmol) in 5 mL of
pentane was added to a suspension of BiCl3 (0.079 g, 0.25 mmol)
in 2 mL of pentane. The green suspension was stirred for 1 h. The
black precipitate was then filtered out, and the green solution was
put into the freezer. After 12 h, a yellow solid formed on the
bottom of vial. The precipitate was filtered out and washed with
cold pentane (2 ꢀ 2 mL) and dried under vacuum to obtain a
1
yellow powder (0.12 g, 25% yield). mp: 123-124 °C (dec). H
1
165 °C (melt and dec). H NMR (C6D6): δ (ppm) 7.24 (s, 6H,
NMR (C6D6): δ (ppm) 7.42 (s, 6H, ArH), 1.49 (s, 54H,
ortho-tBu), 1.35 (s, 27H, para-tBu). 13C NMR (C6D6): δ (ppm)
153.8 (C-OBi), 143.0 (C-tBu), 141.7 (C-tBu), 123.3 (aromatic),
36.1 (ortho-C(CH3)3), 34.2 (para-C(CH3)3), 34.1 (ortho-C-
(CH3)3), 32.3 (para-C(CH3)3). IR (C6H6): 3079, 3025, 2946,
2876, 2856, 1492, 1402, 1200, 1176, 1094, 697, 644 cm-1. UV/
vis (C6H6) λmax/nm (ε/dm3 mol-1 cm-1): 278 (6000), 379 (2420).
The product was not sufficiently stable to submit for elemental
analysis. Complete decomposition of compound 4 to the corre-
sponding phenol occurred after the solution was heated for 3 days
at 75 °C.
ArH), 3.19 (septet, 6H, J = 6 Hz, CHMe2), 1.02 (d, J = 6 Hz,
36H, CH3). 13C NMR (C6D6): δ (ppm) 150.7 (C-OBi), 142.6
(C-iPr), 126.0 (overlapping C-Cl and aromatic), 28.0 (CH(CH3)2),
23.8 (CH(CH3)2). IR (C6H6): 3086, 3007, 1974, 1945, 1801,
1474, 1422, 1318, 1179, 865, 758, 684, 659 cm-1. UV/vis
(C6H6) λmax/nm (ε/dm3 mol-1 cm-1): 281(4466). Anal. calcd.
for BiO3C36H48Cl3: C, 51.22; H, 5.73. Found: C, 50.73; H, 5.79.
Compound 7 was stable after heating for 3 days at 75 °C.
Decomposition to the corresponding phenol occurred at 95 °C.
Bi[O-2,6-iPr2-4-(OCH3)C6H2]3 (8). A solution of 2,6-diiso-
propyl-4-methoxyphenol (0.31 g, 1.5 mmol) in 10 mL of hexane
was added to a solution of Bi[(N(SiMe3)2)]3 (0.35 g, 0.51 mmol)
in 5 mL of hexane. The yellow solution was stirred for 1 day.
Yellow precipitate formed. The precipitate was filtered out,
washed with pentane (2 ꢀ 2 mL), and dried under vacuum to
obtain yellow powder (0.19 g, 45% yield). mp: 65-69 °C (melt
ClBi(O-2,4,6-tBu3C6H2)2 (5). A suspension of the lithium salt
of 2,4,6-tri-tert-butylphenol (0.069 g, 0.26 mmol) in 5 mL of
pentane was added to a suspension of BiCl3 (0.079 g, 0.25 mmol)
in 2 mL of pentane. The dark green suspension was stirred
overnight. The black precipitate was then filtered out, and the
dark green solution was put into the -35 °C freezer. After 12 h,
red solid formed on the bottom of vial. The precipitate was
filtered out, washed with cold pentane (2 ꢀ 2 mL), and dried
under vacuum to obtain a red powder (0.040 g, 0.052 mmol,
40% yield). Red platelet crystals (0.52 ꢀ 0.20 ꢀ 0.09 mm3) of 4
were obtained at -35 °C from a concentrated pentane solution
for X-ray analysis. mp: 146-147 °C. 1H NMR (C6D6): δ (ppm)
7.62 (s, 4H, ArH), 1.65 (s, 32H, ortho-tBu), 1.39 (s, 18H,
para-tBu). 13C NMR (C6D6): δ (ppm) 144.0 (C-OBi), 143.5
1
and dec). H NMR (C6D6): δ (ppm) 6.89 (s, 6H, ArH), 3.51
(septet, 6H, J = 7 Hz, CHMe2), 3.51 (s, 9H, OCH3), 1.25 (d,
36H, J = 7 Hz, CH3). 13C NMR (C6D6): δ (ppm) 141.6 (C-OBi),
127.2 (C-CH3), 126.9 (aromatic), 108.5 (C-iPr), 55.1 (OCH3),
27.9 (CH(CH3)2), 24.3 (CH(CH3)2). IR (C6H6): 3086, 3007,
1974, 1945, 1801, 1474, 1422, 1318, 1179, 865, 758, 684,
659 cm-1. UV/vis (C6H6) λmax/nm (ε/dm3 mol-1 cm-1):
284 (4045). Anal. calcd. for BiO6C39H57: C, 56.38; H, 6.92.

Article
Inorganic Chemistry, Vol. 48, No. 23, 2009 11015
Found: C, 56.35; H, 7.15. Compound 8 was stable after heating
for 3 days at 75 °C. Decomposition to the corresponding phenol
occurred at 95 °C.
be a lithium bismuth oxo cluster, 11c. The yield of the cluster is
quite low (not measured, <5%), and its crystallization was not
repeated. The compound was not isolated from the controlled
addition of lithium aryloxide to 11.
Bi[O-2,6-(C6H5)2C6H3]3 (9). A solution of 2,6-diphenylphe-
nol (0.37 g, 1.5 mmol) in 10 mL ether was added to a solvent
bomb (vacuum schlenck tube) containing a solution of Bi[-
(N(SiMe3)2)]3 (0.35 g, 0.51 mmol) in 10 mL ether. The yellow
solution was heated at 45 °C in an oil bath for 12 h. When the
solution was cooled down to room temperature, yellow cubic
shaped crystals were obtained and filtered out (0.41 g, 87%
yield). Yellow block crystals (0.30 ꢀ 0.20 ꢀ 0.10 mm3) of 9
were obtained by slowly cooling down a concentrated ether
solution from 45 °C to room temperature for X-ray analysis.
Bi[O-2-(CHdCHCH3)C6H4]3 (12). A solution of 2-propenyl-
phenol (0.40 g, 3.0 mmol) in 10 mL of ether was added to a
solution of Bi[(N(SiMe3)2)]3 (0.69 g, 1.0 mmol) in 5 mL of ether.
Yellow precipitate formed after 30 min. After stirring overnight,
the precipitate was filtered out, washed with pentane (2 ꢀ 3 mL),
and dried under vacuum to obtain yellow powder (0.54 g, 88%
1
yield). m.p.: 113-116 °C (melt and dec). H NMR (C6D6): δ
(ppm) 7.50 (d, 3H, J = 8 Hz, ArH), 7.07-6.95 (m, 6H, ArH and
one allyl proton overlapped), 6.77 (t, 6H, J = 7 Hz, ArH), 6.01
(m, 3H, CHdCHCH3), 1.82 (d, 9H, J = 6 Hz, CHdCHCH3).
13C NMR (CDCl3): δ (ppm) 129.1, 127.7, 127.3, 126.7
(aromatic carbons, quarternary carbons were not observed),
122.4 (CHdCHCH3), 121.7 (CHdCHCH3), 18.8 (CH3). IR
(C6H6): 3072, 3028, 1953, 1810, 1478, 1223, 1034, 689, 459
cm-1. UV/vis (C6H6) λmax/nm (ε/dm3 mol-1 cm-1): 292
(1766). Anal. calcd. for BiO3C27H27: C, 53.30; H, 4.47. Found:
C, 53.39; H, 4.57. Compound 12 was stable after heating for 3
days at 75 °C. Decomposition to the corresponding phenol
occurred after heating the solution to 95 °C for 3 days.
1
mp: 133 °C (dec). H NMR (C6D6): δ (ppm) 6.71 (t, 3H, J =
8 Hz, para to O), 6.90-7.37 (m, 36H, ArH). 13C NMR (C6D6): δ
(ppm) 138.1, 130.2, 129.6, 129.2, 128.9, 120.9 (aromatic carbons,
some quaternary carbons were not observed). IR (C6H6):
3071, 3044, 1957, 1810, 1480, 1035, 664, 460 cm-1. UV/vis
(C6H6) λmax/nm (ε/dm3 mol-1 cm-1): 295 (2447). Anal. calcd.
for BiO3C54H39: C, 68.64; H, 4.16. Found: C, 68.22; H, 3.81.
Compound 9 was stable after heating for 3 days at 135 °C.
Decomposition to the corresponding phenol occurred when the
NMR tube was exposed to air for 5 min.
The filtrate ether solution was put into the -35 °C freezer, and
after 2 weeks, light yellow block crystals (0.17 ꢀ 0.06 ꢀ 0.05
mm3) of 9c were obtained.
Bi[O-2-OCH3-6-(CH2CHdCH2)C6H3]3 (13). A solution of
o-eugenol (0.25 g, 1.5 mmol) in 10 mL of pentane was added to a
solution of Bi[(N(SiMe3)2)]3 (0.35 g, 0.51 mmol) in 5 mL of
pentane. Yellow precipitate formed immediately. After stirring
for 5 h, the precipitate was filtered out and dried under vacuum
to obtain yellow powder (0.2560 g, 73% yield). Yellow needle
crystals (0.26 ꢀ 0.18 ꢀ 0.13 mm3) of 13 were obtained from the
reaction mixture in pentane for X-ray analysis. mp: 131 - 134 °C
(melt and dec). 1H NMR (C6D6): δ (ppm) 6.94 (d, 3H, J = 8 Hz,
ArH), 6.55 (t, 3H, J = 8 Hz, ArH), 6.25 (d, 3H, J = 8 Hz, ArH),
6.19-6.10 (m, 3H, CH2CH=CH2), 5.18 (dd, 3H, J1 = 2 Hz,
J2 = 9 Hz, CH2CHdCH2), 5.06 (dd, 3H, J1 = 2 Hz, J2 = 6 Hz,
CH2CHdCH2), 3.51 (d, 6H, J = 7 Hz, CH2CHdCH2), 3.09 (s,
9H, OCH3). 13C NMR (C6D6): δ (ppm) 149.6 (C-OBi),
148.5 (C-OCH3), 138.8 (aromatic), 133.3 (C-allyl), 123.0
(aromatic), 117.7 (aromatic), 114.6 (CH2CHdCH2), 108.7
(CH2CHdCH2), 34.9 (CH2CHdCH2), 54.9 (OCH3). IR
(C6H6): 3075, 3028, 1957, 1816, 1479, 1273, 1036, 663, 460
cm-1. UV/vis (C6H6) λmax/nm (ε/dm3 mol-1 cm-1): 281
(1415). Anal. calcd. for BiO6C30H33: C, 51.58; H, 4.76. Found:
C, 51.29; H, 4.78. Compound 13 was stable after heating for
3 days at 95 °C. Decomposition to the corresponding phenol
occurred after heating the solution to 135 °C for 3 days.
Bi[O-2,6-(CH2C6H5)2C6H3]3 (10). A solution of 2,6-dibenzyl-
phenol (0.41 g, 1.5 mmol) in 10 mL ether was added to a solvent
bomb containing a solution of Bi[(N(SiMe3)2)]3 (0.35 g, 0.51
mmol) in 10 mL ether. The yellow solution was heated at
45 °C in an oil bath for 12 h, then solvent was removed under
vacuum to obtain yellow solid. The yellow solid was dissolved in
ether and put into a -33 °C freezer for recrystallization; yellow
cubic crystals were obtained. The supernatant was decanted and
the crystals were dried under vacuum (0.45 g, 88% yield). Yellow
needle crystals (0.15 ꢀ 0.10 ꢀ 0.08 mm3) of 10 were obtained at
-35 °C from a concentrated ether solution for X-ray analysis.
mp: 152-154 °C (dec). 1H NMR (C6D6): δ (ppm) 6.92-
7.16 (m, 36H, ArH), 6.61 (t, 3H, J = 8 Hz, para to O),
4.11 (s, 12H, CH2Ph). 13C NMR (C6D6): δ (ppm) 155.3 (C-O),
142.5 (quat), 133.3, 129.3, 128.91, 128.88, 126.4 (aromatic), 122.0
(ortho to O), 37.2 (CH2Ph). IR (C6H6): 3071, 3044, 1958, 1816,
1479, 1036, 663, 459 cm-1. UV/vis (C6H6) λmax/nm (ε/dm3 mol-1
cm-1): 277 (1596). Anal. calcd. for BiO3C60H51: C, 70.03; H, 5.00.
Found: C, 69.75; H, 5.06. Compound 10 was stable after heating
for 3 days at 95 °C. Decomposition to the corresponding phenol
occurred after heating the solution to 135 °C for 3 days.
Bi[O-2-(CH2CHdCH2)C6H4]3 (11). A solution of 2-allylphe-
nol (0.40 g, 3.0 mmol) in 10 mL of ether was added to a solution of
Bi[(N(SiMe3)2)]3 (0.69 g, 1.0 mmol) in 5 mL of ether. Yellow
precipitate formed at once. After stirring for 4 h, the precipitate was
filtered out, washed with pentane (2 ꢀ 3 mL), and dried under
vacuum to obtain yellow powder (0.48 g, 80% yield). mp: 110-
113 °C (melt and dec). 1H NMR (CDCl3): δ (ppm) 7.07 (d, 3H,
J=7Hz, ArH), 6.95 (t, 3H, J=7Hz, ArH), 6.69 (t, 3H, J= 7Hz,
ArH), 6.56 (d, 3H, J = 7 Hz, ArH), 5.77 (m, 3H, CH2CHdCH2),
4.82 (d, 3H, J = 10 Hz, CH2CHdCH2), 4.67 (d, 3H, J = 17 Hz,
CH2CHdCH2), 3.20 (d, 6H, J = 6 Hz, CH2CHdCH2). 13C NMR
Bi[O-2-OCH3-4-(CH2CHdCH2)C6H3]3 (14). A solution of
eugenol (0.25 g, 1.5 mmol) in 10 mL of pentane was added to a
solution of Bi[(N(SiMe3)2)]3 (0.35 g, 0.51 mmol) in 5 mL of
pentane without stirring. The solution became cloudy at once
then became clear again after 30 min. After 1 day undisturbed,
needle-shaped crystals formed. These were filtered out and dried
under vacuum to obtain light yellow solid (0.26 g, 73% yield).
Yellow block crystals (0.30 ꢀ 0.20 ꢀ 0.10 mm3) of 14 were
obtained at -35 °C from a concentrated ether solution for X-ray
1
analysis. mp: 131-133 °C (melt and dec). H NMR (C6D6): δ
(ppm) 7.04 (d, 3H, J = 8 Hz, ArH), 6.70 (d, 3H, J = 8 Hz, ArH),
6.35 (s, ArH), 5.98-5.84 (m, 3H, CH2CH=CH2), 5.06-5.00
(m, 6H, CH2CHdCH2), 3.25 (d, 6H, CH2CHdCH2), 3.38 (s,
9H, OCH3). 13C NMR (C6D6): δ (ppm) 150.7 (C-OBi), 148.9
(C-OCH3), 138.8 (C-allyl), 129.5, 121.8, 121.6 (aromatic), 114.8
(CH2CHdCH2), 110.9 (CH2CHdCH2), 40.0 (CH2CHdCH2),
55.1 (OCH3). IR (C6H6): 3071, 3043, 1956, 1808, 1496, 1261,
664, 459 cm-1. UV/vis (C6H6) λmax/nm (ε/dm3 mol-1 cm-1): 288
(1605). Anal. calcd. for BiO6C30H33: C, 51.58; H, 4.76. Found:
C, 51.74; H, 4.70. Compound 14 was stable after heating
for 3 days at 135 °C. Decomposition to the corresponding
phenol occurred when the NMR tube was exposed to air
for 5 min.
(CDCl3):
δ (ppm) 141.1 (C-O), 132.1 (C-allyl), 130.2,
127.2, 122.1, 121.8 (aromatic), 116.0 (CH2CHdCH2), 77.4
(CH2CHdCH2), 34.7 (CH2CHdCH2). IR (C6H6): 3075, 3024,
1956, 1817, 1486, 1226, 1034, 664, 459 cm-1. UV/vis (C6H6)
λ
max/nm (ε/dm3 mol-1 cm-1): 278 (1230). Anal. calcd. for
BiO3C27H27: C, 53.30; H, 4.47. Found: C, 53.04; H, 4.75. Com-
pound 11 was stable after heating for 3 days at 45 °C. Decom-
position to the corresponding phenol occurred after heating the
solution to 75 °C for 3 days.
Yellow block crystals (0.25 ꢀ 0.25 ꢀ 0.20 mm3) were obtained
by slow evaporation of the filtrate pentane solution and found to

11016 Inorganic Chemistry, Vol. 48, No. 23, 2009
Kou et al.
Table 4. Crystallographic Data and Summary of Data Collection and Structure Refinement
compunds
2
5
6
7
9
formula
fw
C
740.75
monoclinic
P21/c
203(2)
11.545(3)
28.528(6)
10.836(2)
90.00
108.751(3)
90.00
36H51BiO3
C36H58BiClO2
767.25
triclinic
P-1
213(2)
9.6368(5)
13.9896(8)
14.2872(8)
78.5150(10)
85.6060(10)
72.4230(10)
1798.81(17)
2
C36H48BiBr3O3
977.45
triclinic
P-1
213(2)
9.371(4)
10.783(5)
18.755(9)
86.072(7)
80.293(7)
81.010(7)
1843.2(14)
2
C36H48BiCl3O3
844.07
triclinic
P-1
213(2)
9.344(2)
10.755(3)
18.738(4)
86.328(4)
79.338(4)
80.079(4)
1821.9(7)
2
C54H39BiO3
944.83
monoclinic
P21/n
213(2)
13.0039(6)
18.9566(9)
16.4856(8)
90
101.0720(10)
90
3988.2(3)
4
1.574
4.467
1.65-28.20
28608
crystal syst
space group
T, K
˚
a, A
˚
b, A
˚
c, A
R, deg
β, deg
γ, deg
3
˚
V, A
Z
3379.5(13)
4
1.456
dcalcd, mg m-3
1.417
5.003
1.55-22.50
10587
1.761
8.066
1.91-22.50
10692
1.539
5.091
2.71-23.27
10543
3
μ, mm-1
θ range (deg)
N measd
N ind
5.249
1.99-27.00
37349
7318 [R(int) = 0.0261] 4714[R(int) = 0.0810] 4808 [R(int) = 0.1632] 4755 [R(int) = 0.0448] 9339 [R(int) = 0.0288]
R1
ωR2
GOF
0.0198
0.0476
1.027
0.0309
0.0808
1.065
1.117 and -1.477
0.0565
0.1295
1.014
2.731 and -3.276
0.0225
0.0542
1.002
0.865 and -0.802
0.0234
0.0550
1.040
1.049 and -0.616
max. residual density peak 0.612 and -0.395
-3
˚
and hole (e A
)
3
compounds
10
13
14
6c C5H12
3
9c
11c
formula
fw
C
60H51BiO3
C60H66Bi2O12
C30H33BiO6
698.54
monoclinic
P21/c
213(2)
8.1427(10)
24.223(3)
13.9470(18)
90.00
99.825(2)
90.00
2710.5(6)
4
1.712
6.546
1.68-28.23
19515
6361 [R(int) =
0.0334]
0.0326
0.0729
1.068
C77H102Bi4Br6O8 C216H160Bi32O56
C90H90Bi4Li2O12
2213.42
triclinic
P-1
100(2)
12.6805(9)
13.1859(9)
14.0822(10)
109.9310(10)
104.1920(10)
101.7880(10)
2036.2(2)
1
1.805
8.677
1.73-28.28
20850
9083 [R(int) =
0.0232]
0.0208
0.0472
1.042
1028.99
triclinic
P-1
1393.06
monoclinic
P21/c
2470.96
triclinic
P-1
10338.80
triclinic
P-1
crystal syst
space group
T, K
213(2)
223(2)
218(2)
100(2)
˚
a, A
11.2561(7)
13.3945(8)
16.3952(10)
80.3940(10)
83.9810(10)
69.2090(10)
2275.7(2)
2
1.502
3.921
1.64-28.16
16674
10309 [R(int) =
0.0292]
0.0392
0.0862
1.014
12.5971(7)
17.4214(10)
12.9355(8)
90.00
104.8130(10)
90.00
2744.5(3)
2
1.686
6.465
2.00-28.31
27206
6548 [R(int) =
0.0322]
0.0361
0.0967
1.091
12.77718(6)
13.2642(6)
14.9861(6)
115.1620(10)
97.3210(10)
92.2500(10)
2266.74(17)
1
19.155(2)
19.323(2)
22.046(2)
92.198(2)
114.670(2)
107.594(2)
6939.6(13)
1
˚
b, A
˚
c, A
R, deg
β, deg
γ, deg
3
˚
V, A
Z
dcalcd, mg m-3
1.810
10.429
2.474
20.260
3
μ, mm-1
θ range (deg)
N measd
N ind
1.52-28.30
14249
1.36-27.52
59825
9372 [R(int) =
0.0244]
0.0283
30862 [R(int) =
0.0451]
0.0444
R1
ωR2
GOF
0.0700
1.002
0.1202
1.028
max. residual density peak 2.222 and -1.173 1.411 and -1.142 1.205 and -0.955 1.755 and -1.277 3.734 and -2.649 1.206 and -0.956
-3
˚
and hole (e A
)
3
General X-ray Crystal Structure Information. Data were
collected on a Bruker SMART APEX CCD diffractometer or
a Bruker SMART 1000 CCD diffractomer at variable low
temperature using Mo KR radiation. The crystallographic data
and some details of the data collections and refinements of the
structures are given in Table 4. Absorption corrections in all
cases were applied by SADABS. Structures were solved using
direct methods or the Patterson function, completed by subse-
quent difference Fourier syntheses, and refined by full matrix
least-squares procedures on F2. The highly disordered solvent
pentane molecule located on an inversion center in 6c was
rendered using a diffuse contribution obtained by the program
SQUEEZE.72 The correction of the X-ray data by SQUEEZE,
65 electron/cell, is close to the required value, 42 electron/cell. In
all structures, non-H atoms were refined with anisotropic
thermal parameters. One of the ;CHdCH2 groups in 13 and
two ;CH2; groups in 14 are disordered over two positions and
were refined with the same occupations for both positions. H
atoms were treated in calculated positions. All calculations were
performed using the Bruker SHELXTL package.73
Acknowledgment. This material is based on work supported
by the National Science Foundation under Grant No. CHE-
133866 and the Welch Foundation under grant No. P-1459. We
are also grateful to several reviewers who gave us detailed and
thoughtful comments in order to improve this manuscript.
Supporting Information Available: X-ray crystallographic
data in CIF format. This material is available free of charge
via the Internet at http://pubs.acs.org.
(73) Sheldrick, G. M. SHELXS-97, Program for Crystal Structure Solu-
tion and Refinement; Institut fur Anorganische Chemie: Gottingen, Germany,
1998.
(72) van der Sluis, P. V.; Spek, A. L. Acta Crystallogr. 1990, A46, 194–201.