A stabilized triarylbismuthane imide: Synthesis and first X-ray structure analysis

Article abstract of DOI:10.1021/om970996v

The synthesis and reactions of the first moisture-insensitive triarylbismuthane imide (7), bearing an oxazoline ring at a position ortho to the carbon bearing the bismuth atom, are described. The first X-ray crystallographic study of bismuthane imide has been carried out for compound 7, which revealed that the bismuth center possesses a distorted-trigonalbipyramidal geometry and the Bi-N(imide) bond length (2.13(1) ?) falls in the range of known Bi-N single bonds, suggesting a polarized Bi⁺-N^- bond rather than a Bi=N double bond.

Full text of DOI:10.1021/om970996v

Organometallics 1998, 17, 1013-1017
1013
Articles
A Sta bilized Tr ia r ylbism u th a n e Im id e: Syn th esis a n d
F ir st X-r a y Str u ctu r e An a lysis
Tohru Ikegami† and Hitomi Suzuki*
Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa,
Sakyo-ku, Kyoto 606-8224, J apan
Received November 13, 1997
The synthesis and reactions of the first moisture-insensitive triarylbismuthane imide (7),
bearing an oxazoline ring at a position ortho to the carbon bearing the bismuth atom, are
described. The first X-ray crystallographic study of bismuthane imide has been carried out
for compound 7, which revealed that the bismuth center possesses a distorted-trigonal-
bipyramidal geometry and the Bi-N(imide) bond length (2.13(1) Å) falls in the range of
known Bi-N single bonds, suggesting a polarized Bi+-N- bond rather than a BidN double
bond.
In tr od u ction
gen.3,6 Since they also decompose slowly in solution, it
is not easy to obtain pure bismuthane imides by recrys-
tallization.
Bismuthane imides of the general formula R3BidNE
are the bismuth analogues of phosphane imides R3PdNE,
which have long been known as intermediates in the
Staudinger and aza-Wittig reactions.1 In contrast to the
analogous compounds derived from lighter group 15 and
16 elements, bismuthane imides have remained almost
unexamined until recently. The first synthesis of bis-
muthane imide was reported in 1964 by Wittig and
Hellwinkel, who obtained triphenylbismuthane [(4-
methylphenyl)sulfonyl]imide (1; Ph3BidNTs; Ts )
4-MeC6H4SO2) as a moisture-sensitive solid by treating
triphenylbismuthane (Ph3Bi) with anhydrous Chloram-
ine-T in boiling acetonitrile.2 The reactivity of this and
related triarylbismuthane imides toward electrophiles
has been examined for aldehydes, benzoyl chloride, and
phenyl isocyanate.3 The reaction of triarylbismuthanes
with the iminoiodobenzene PhIdNTs4 is convenient for
the in situ generation of bismuthane imides,5 while the
metathesis between triarylbismuth dihalides and sul-
fonamides is also efficient for the preparation of similar
imides.6 All known bismuthane imides have a sulfonyl
group on the imido nitrogen atom and are thereby
thermally stabilized. These imides gradually decompose
in air due to their moisture instability, although they
can be stored over a period of weeks under dry nitro-
We report herein the synthesis and first X-ray struc-
ture analysis of a highly stabilized bismuthane imide,
[2-(4,4-dimethyl-2-oxazolin-2-yl)phenyl]bis(4-methyl-
phenyl)bismuthane [(trifluoromethyl)sulfonyl]imide (7),
bearing an oxazoline ring as the intramolecularly
coordinating group at the position ortho to the carbon
bonded to bismuth.
Resu lts a n d Discu ssion
Imide 7 was obtained in four steps, starting from tris-
(4-methylphenyl)bismuthane (Tol3Bi); treatment of bis-
(4-methylphenyl)bismuth trifluoromethanesulfonate-
hexamethylphosphoric triamide (HMPA) complex (Tol2-
BiOTf‚2HMPA; Tf ) CF3SO2) with an excess of [2-(4,4-
dimethyl-2-oxazolin-2-yl)phenyl]magnesium bromide (2)
gave the corresponding mixed triarylbismuthane 3 in
63% yield.7 Bismuthane 3 was less stable than Tol3Bi
and readily decomposed during column chromatography
on alumina or silica gel using chloroform as the eluent.
Nevertheless, chloro[2-(4,4-dimethyl-2-oxazolin-2-yl)-
phenyl](4-methylphenyl)bismuthane (4) was obtained in
good yield. As with other halobismuthanes containing
an intramolecularly coordinating group,8 compound 4
was moisture-insensitive. Bismuthane 3 was converted
by the action of phenyliodine dichloride (PhICl2) to the
† Present address: Department of Polymer Science and Engineering,
Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585,
J apan.
(1) (a) Gololobov, Y. G.; Zhmurova, I. N.; Kasukhin, L. F. Tetrahe-
dron 1981, 37, 437. (b) Gololobov, Y. G.; Kasukhin, L. F. Tetrahedron
1992, 48, 1353. (c) J ohnson, A. W. Ylides and Imines of Phosphorus;
Wiley: New York, 1993.
(2) Wittig, G.; Hellwinkel, D. Chem. Ber. 1964, 97, 789.
(3) Suzuki, H.; Nakaya, C.; Matano, Y.; Ogawa, T. Chem. Lett. 1991,
105.
(4) Yamada, Y.; Yamamoto, T.; Okawara, M. Chem. Lett. 1975, 361.
(5) Suzuki, H.; Ikegami, T. J . Chem. Res. Synop. 1996, 24.
(6) Pasenok, S. V.; Kirij, N. V.; Yagupolskii, Y. L.; Naumann, D.;
Tyrra, W. J . Fluorine Chem. 1993, 63, 179.
(7) (a) Matano, Y.; Miyamatsu, T.; Suzuki, H. Organometallics 1996,
15, 1951. (b) Matano, Y.; Miyamatsu, T.; Suzuki, H. Unpublished
results.
(8) (a) Ohkata, K.; Takemoto, S.; Ohnishi, M.; Akiba, K.-y. Tetra-
hedron Lett. 1989, 30, 4841. (b) Suzuki, H.; Murafuji, T.; Azuma, N.
J . Chem. Soc., Perkin Trans. 1 1993, 1169. (c) Murafuji, T.; Azuma,
N.; Suzuki, H. Organometallics 1995, 14, 1542. (d) Murafuji, T.; Mutoh,
T.; Satoh, K.; Tsunenari, K.; Azuma, N.; Suzuki, H. Organometallics
1995, 14, 3848. (e) Murafuji, T.; Mutoh, T.; Sugihara, Y. J . Chem. Soc.,
Chem. Commun. 1996, 1693.
S0276-7333(97)00996-5 CCC: $15.00 © 1998 American Chemical Society
Publication on Web 02/20/1998

1014 Organometallics, Vol. 17, No. 6, 1998
Ikegami and Suzuki
Sch em e 1
F igu r e 1. ORTEP drawing of compound 7, with the
crystallographic numbering scheme. The percentage prob-
ability level of the ellipsoids in this drawing is 30%.
Sch em e 2
to stand in CDCl3. When heated around 200 °C under
reduced pressure (1 mmHg) for 10 min, imide 7 decom-
posed to give amidobismuthane 5 as the major product
(Scheme 2). Below 180 °C, no significant change was
observed.
corresponding dichloride 6 in 80% yield. When it was
gently heated in an organic solvent, dichloride 6 slowly
decomposed to give chlorobismuthane 4. On treatment
with a 2:1 molar ratio of potassium tert-butoxide (t-
BuOK) and trifluoromethanesulfonamide (TfNH2) in
tetrahydrofuran (THF) at room temperature, dichloride
6 gave the corresponding bismuthane imide 7 in 90%
yield, while chlorobismuthane 4 was converted to the
amidobismuthane 5 by the action of a 1:1 molar mixture
of t-BuOK and TfNH2 (Scheme 1). In contrast to bis-
(4-methylphenyl)[N-(4-methylphenyl)sulfonamido]bis-
muthane (Tol2BiNHTs),5 compound 5 was thermally
stable and did not disproportionate when left to stand
in solution. All new organobisumuth compounds 3-7
were fully characterized by 1H and 13C NMR and IR
spectroscopy as well as by elemental analyses.
The imide 7 is soluble in dichloromethane, chloroform,
and THF but poorly soluble in diethyl ether and hexane;
it can be readily purified by recrystallization from a
dichloromethane-diethyl ether mixture. Compound 7
is not sensitive to moisture and can be handled under
atmospheric conditions. After several months of storage
on a bench shelf, crystals of imide 7 were still intact. In
marked contrast to the known bismuthane imides,3 it
did not show any sign of decomposition when allowed
Although imide 1 is easily hydrolyzed to give triphen-
ylbismuthane oxide (Ph3BidO),6 imide 7 underwent
slow hydrolysis in boiling ethanol, giving a mixture of
Tol3Bi, amidobismuthane 5, and 2-(4,4-dimethyl-2-ox-
azolin-2-yl)benzene in 49, 34, and 66% yields, respec-
tively, based on imide 7. While a bismuthane imide
(Tol3BidNTs) oxidized benzopinacol to benzophenone in
almost quantitative yield within 30 min at room tem-
perature,5 it required 24 h for imide 7 to complete the
oxidation. In the former case, Tol3Bi and TsNH2 were
recovered in good yields, while in the latter case
benzophenone, amidobismuthane 5, and toluene were
all obtained in around 90% yields with no bismuthane
3 being formed. These results clearly show that the
introduction of an oxazoline ring at the position ortho
to the carbon bonded to bismuth changes not only the
reactivity of bismuthane imides toward the pinacol but
also the pathway of the oxidation.
To obtain an insight into the structure of bismuthane
imide 7, an X-ray crystallographic study was performed.
As shown in Figure 1, the bismuth atom is attached to
the three carbon atoms C(1), C(12), and C(19) and one

A Stabilized Triarylbismuthane Imide
Organometallics, Vol. 17, No. 6, 1998 1015
Sch em e 3
nitrogen atom N(1), with C-Bi-C bond angles of 112.0-
(5)-119.9(5)° and N(1)-Bi-C bond angles of 94.2(5)-
107.8(5)°. The oxazoline nitrogen atom N(2) coordinates
intramolecularly to the bismuth center from the op-
posite side of N(1) with a distance of 2.69(1) Å and an
N(1)-Bi-N(2) bond angle of 163.5(4)°. The intramo-
lecular distance between the bismuth and the N(2)
atoms is longer than the sum of their covalent radii (2.16
Å) but shorter than that of their van der Waals radii
(ca. 3.6 Å).9 According to these findings, the geometry
around the bismuth center can be regarded as a
distorted-trigonal-bipyramidal structure (TBP). Since
the coordination of N(2) to the bismuth center fixes the
oxazoline ring, two gem-methyl groups on it are located
above the plane made by two equatorial tolyl groups.
From an open C(12)-Bi-C(19) side, one of the sulfonyl
oxygen atoms O(1) coordinates to the bismuth at a
distance of 2.97(1) Å, as shown in Figure 1; this value
is intermediate between the sums of covalent radii (2.12
Å) and of van der Waals radii (ca. 3.5 Å) of bismuth and
oxygen atoms.9,10 The bismuth atom is located 0.49 Å
above the plane made by the three carbon atoms C(1),
C(12), and C(19).11 The sum of three C-Bi-C bond
angles (345.4°) lies between the predicted values of a
TBP geometry (360°) and a tetrahedral geometry (328.5°).
These observations are suggestive of some contribution
of a tetrahedral nature to the total geometry of the
bismuth center.
The most interesting feature of compound 7 is the Bi-
N(1) bond length. The observed value (2.13(1) Å) falls
in the range of the known Bi-N single-bond distances:
2.12(2)-2.28(2) Å for (Ph2N)3Bi,12 2.180(21)-2.189(18)
Å for (Me2N)3Bi,13 2.14(2)-2.214(13) Å for [(t-Bu3C6H2)-
NH]3Bi,14 2.158(4)-2.174(5) Å for a cyclic amidobis-
muthane,15 and 2.101(7)-2.237(7) Å for a cubic ami-
dobismuthane.16 A recent theoretical study on the
electronic configuration of H3BidNH and H2Bi-NH2 at
the MP2/DZ-d level estimated the lengths of the BidN
and Bi-N bonds to be 1.997 and 2.133 Å, respectively.17
Therefore, the Bi-N(1) bond in compound 7 can be
regarded as a polarized single bond, Bi+-N-, rather
than a double bond, BidN.
(C(7)-C(9), N(2), O(3)) are nearly coplanar with a mean
deviation of 0.012 Å from the plane (C(1)-C(6)) defined
by one of the benzene rings. These observations strongly
suggest that the N(2)-Bi-N(1) linkage has a hyperva-
lent bonding nature and that a charge on the Bi-
N(imide) bond would be distributed over the array of
N(2)-Bi-N(1)-S-O(1) atoms in a push-pull manner
from the N(2) toward the O(1) end. The N(1)-S bond
distance, 1.53(1) Å, is shorter than the sum of their
covalent radii (1.74 Å), which suggests a double-bonding
nature. This value is much shorter than those of
ArIdNTs (1.611(2) and 1.595(4) Å), for which an SdN
double-bond nature has also been proposed.18 There-
fore, it is reasonable to suppose that the structure C in
Scheme 3 is the predominant resonance structure for
imide 7. In addition to this resonance between the
imide and sulfonyl functions, the intramolecular coor-
dination of the O(1) atom to the bismuth may also be
effective for the stabilization of the Bi-N(imide) bond.
X-ray crystallography and 1H NMR spectroscopy
support the conclusion that the structure of imide 7 is
similar both in solution and in the solid state. A high-
field shift (δ 0.68) of two gem-methyl groups on the
oxazoline ring of imide 7 with respect to that (δ 1.13) of
bismuthane 3 is probably due to the ring current effect
of two tolyl groups, which have been found to partially
eclipse the resonances of these methyl groups in the
solid state. The ortho aromatic proton of the oxazoline-
substituted phenyl group appears at δ 8.97, which is
0.99 ppm lower than that of compound 3. A low-field
shift of the ortho proton is caused by the deshielding
effect of the nitrogen N(1) atom. These observations are
indicative of the TBP structure of imide 7 in solution.
In conclusion, the oxazoline ring plays an important
role as an intramolecularly coordinating ligand in the
stability and reactivity of bismuthane imide 7. The
bismuth center of 7 has been found to possess the
distorted-trigonal-bipyramidal geometry, in which the
imide bond is best described as a polarized Bi+-N-
single bond.
Coordination of the oxazoline nitrogen atom to the
bismuth should play an important role in the stabiliza-
tion of the polarized Bi-N bond, where the Bi, N(1), S,
and O(1) atoms as well as all ring atoms of the oxazoline
(9) Bondi, A. J . Phys. Chem. 1964, 68, 441. Since the van der Waals
radius of bismuth is not yet known, we postulated this value to be
similar to that of antimony, 2.12 Å.
(10) If the coordination by oxygen O(1) is taken into consideration,
the geometry around the bismuth center may be regarded as distorted
octahedral.
(11) The observed distance between the bismuth atom and the
corresponding plane is 0 Å for Ph3BiCl2 and 0.73 Å for Ph4Bi+ClO4
:
-
Exp er im en ta l Section
Barton, D. H. R.; Charpiot, B.; Dau, E. T. H.; Motherwell, W. B.;
Pascard, C.; Pichon, C. Helv. Chim. Acta 1984, 67, 586.
(12) Clegg, W.; Compton, N. A.; Errington, R. J .; Norman, N. C.;
Wishart, N. Polyhedron 1989, 8, 1579.
(13) Clegg, W.; Compton, N. A.; Errington, R. J .; Fisher, G. A.;
Green, M. E.; Hockless, D. C. R.; Norman, N. C. Inorg. Chem. 1991,
30, 4680.
(14) Burford, N.; Macdonald, C. L. B.; Robertson, K. N.; Cameron,
T. S. Inorg. Chem. 1996, 35, 4013.
(15) Wirringa, U.; Roesky, H. W.; Noltemeyer, M.; Schmidt, H.-G.
Inorg. Chem. 1994, 33, 4607.
Gen er a l Com m en ts. All reactions were carried out under
an atmosphere of dry argon. THF and diethyl ether (Et2O)
were distilled from benzophenone ketyl under argon before use.
2-(4,4-Dimethyl-2-oxazolin-2-yl)phenyl bromide was prepared
according to the reported procedure.19 Commercially available
reagents were used without further purification. Column
chromatography was performed on silica gel (Wakogel, 200
mesh). Melting points were determined on a Yanagimoto hot-
(16) Edwards, A. J .; Beswick, M. A.; Galsworthy, J . R.; Paver, M.
A.; Raithby, P. R.; Rennie, M.-A.; Russell, C. A.; Verhorevoort, K. L.;
Wright, D. S. Inorg. Chim. Acta 1996, 248, 9.
(17) Koketsu, J .; Ninomiya, Y.; Suzuki, Y.; Koga, N. Inorg. Chem.
1997, 36, 694.
(18) Mishra, A. K.; Olmstead, M. M.; Ellison, J . J .; Power, P. P.
Inorg. Chem. 1995, 34, 3210.
(19) Meyers, A. I.; Temple, D. L.; Haidukewych, D.; Mihelich, E. D.
J . Org. Chem. 1974, 39, 2787.

1016 Organometallics, Vol. 17, No. 6, 1998
Ikegami and Suzuki
stage apparatus and are uncorrected. 1H and 13C NMR spectra
were recorded on a Varian Gemini-200 spectrometer in CDCl3
with tetramethylsilane as an internal standard. IR spectra
were recorded on a Shimadzu FTIR-8100 spectrophotometer.
Elemental analyses were performed at Microanalytical Labo-
ratory, Institute of Chemical Research, Kyoto University.
[2-(4,4-Dim eth yl-2-oxa zolin -2-yl)p h en yl]bis(4-m eth yl-
p h en yl)bism u th a n e (3). This compound was prepared ac-
cording to a procedure recently established in our laboratory.7b
To a solution of [2-(4,4-dimethyl-2-oxazolin-2-yl)phenyl]mag-
nesium bromide 2, prepared from the corresponding bro-
moarene (2.61 g, 10.3 mmol) and Mg (0.267 g, 11.0 mmol) in
THF (20 mL), was added in one portion a solution of Tol2-
BiOTf‚2HMPA7a (4.76 g, 5.3 mmol) in the same solvent (10
mL) at -20 °C under Ar. The resulting mixture was stirred
at room temperature for 30 min and then poured into cold
brine. The product was extracted with benzene (50 mL × 3).
The combined extracts were dried and then concentrated to
one-tenth of the original volume. Methanol (50 mL) was added
and the mixture was allowed to stand at -15 °C to give
bismuthane 3 as colorless crystals (1.89 g, 63%). Mp: 112-
113 °C. 1H NMR: δ 1.13 (s, 6H), 2.30 (s, 6H), 3.97 (s, 2H),
7.15 (d, J AB ) 7.3 Hz, 4H), 7.25 (dt, J ) 7.3 and 1.7 Hz, 1H),
7.38 (dt, J ) 7.4 and 1.7 Hz, 1H), 7.62 (d, J AB ) 7.8 Hz, 4H),
7.85 (dd, J ) 7.2 and 1.5 Hz, 1H), 7.98 (dd, J ) 7.5 and 1.7
Hz, 1H). 13C NMR: δ 21.5, 28.4, 67.7, 79.0, 127.3, 129.4, 131.0,
133.0, 133.1, 136.5, 137.8, 139.4, 159.6, 160.2, 164.2. IR
Ta ble 1. Cr ysta llogr a p h ic a n d Str u ctu r e Solu tion
Da ta for Im id e 7
compd formula
fw
C26H26BiF3N2SO3
712.54
cryst size, mm
cryst syst
space group
0.32 × 0.10 × 0.10
monoclinic
C2/c
a, Å
b, Å
c, Å
25.556(3)
15.137(3)
17.563(2)
125.263(7)
5547(1)
â, deg
V, Å3
Z
8
D, g cm-3
1.706
T, °C
23.0
radiation; λ, Å
µ(Mo KR), cm-1
2θmax, deg
no. of observns
no. of rflns obsd
no. of variables
rfln/param ratio
max peak in final diff map, e/Å3
R
Mo KR; 0.710 69
64.69
55.0
6767 (6619 unique)
2652 (I > 3.00σ(I))
325
8.16
1.34
0.047
Rw
0.060
goodness of fit
1.10
concentrate with ethanol (30 mL) gave compound 6 as yellow
crystals (1.02 g, 80%). Mp: 187-189 °C dec. 1H NMR: δ 0.96
(s, 6H), 2.40 (s, 6H), 4.15 (s, 2H), 7.43 (d, J AB ) 7.7 Hz, 4H),
7.53 (dt, J ) 7.4 and 1.2 Hz, 1H), 7.66 (dt, J ) 7.8 and 1.6 Hz,
1H), 7.79 (dd, J ) 7.8 and 1.1 Hz, 1H), 8.07 (dd, J ) 7.4 and
1.6 Hz, 1H), 8.5 (broad s, 4H). 13C NMR: δ 21.3, 27.6, 67.9,
81.3, 124.6, 128.9, 129.8, 130.4, 131.0 (broad), 131.8, 134.7,
136.0 (broad), 140.9, 151.8 (broad), 162.2, 167.7. IR (KBr):
1649 (CdN), 1362, 1320, 1181, 1086, 1005, 992, 953, 808, 725,
475 cm-1. Anal. Calcd for C25H26BiCl2NO: C, 47.19; H, 4.12;
N, 2.20. Found: C, 46.89; H, 4.02; N, 2.13.
(KBr): 1644 (CdN), 1309, 1073, 1038, 795, 729, 683, 480 cm-1
.
Anal. Calcd for C25H26BiNO: C, 53.10; H, 4.63; N, 2.48.
Found: C, 53.18; H, 4.60; N, 2.51.
C h lo r o [2-(4,4-d im e t h y l-2-o x a zo lin -2-y l)p h e n y l](4-
m eth ylp h en yl)bism u th a n e (4). Bismuthane 3 (1.70 g, 3.0
mmol) was passed through a silica gel column using CHCl3
as the eluent. The chlorobismuthane 4 was obtained as
colorless crystals (1.22 g, 80%). Mp: 184-186 °C. 1H NMR:
δ 1.13 (s, 3H), 1.43 (s, 3H), 2.24 (s, 3H), 4.24 (d, J AB ) 8.5 Hz,
1H), 4.30 (d, J AB ) 8.5 Hz, 1H), 7.27 (d, J AB ) 7.4 Hz, 2H),
7.56 (dt, J ) 7.5 and 1.2 Hz, 1H), 7.86 (dt, J ) 7.5 and 1.3 Hz,
1H), 7.98 (dd, J ) 7.2 and 1.2 Hz, 1H), 8.01 (d, J AB ) 7.9 Hz,
2H), 9.10 (d, J ) 7.3 Hz, 1H). 13C NMR: δ 21.5, 28.1, 29.2,
67.1, 80.7, 127.9, 131.1, 131.9, 132.0, 135.9, 136.8, 137.4, 137.8,
175.0, 176.0, 179.4. IR (KBr): 1630 (CdN), 1375, 1327, 1088,
938, 793, 733, 478 cm-1. Anal. Calcd for C18H19BiClNO: C,
42.41; H, 3.76; N, 2.75. Found: C, 42.43; H, 3.68; N, 2.70.
[2-(4,4-Dim e t h yl-2-oxa zolin -2-yl)p h e n yl](4-m e t h yl-
ph en yl)[N-(tr iflu or om eth yl)su lfon am ido]bism u th an e (5).
A solution of compound 4 (0.493 g, 0.97 mmol) in THF (20 mL)
was added to a solution of TfNH2 (0.144 g, 0.97 mmol) and
t-BuOK (0.108 g, 0.97 mmol) in the same solvent (10 mL), and
the resulting mixture was stirred at room temperature for 3
h. The solvent was evaporated to dryness, and the residue
was extracted with CH2Cl2 (5 mL × 6). The combined extracts
were concentrated to give compound 5 as crystals (0.603 g,
100%). Mp: 153-155 °C dec. 1H NMR: δ 1.01 (s, 3H), 1.42
(s, 3H), 2.27 (s, 3H), 3.96 (broad s, 1H), 4.25 (d, J AB ) 8.5 Hz,
1H), 4.30 (d, J AB ) 8.5 Hz, 1H), 7.28 (d, J AB ) 8.0 Hz, 2H),
7.60 (dt, J ) 7.5 and 1.1 Hz, 1H), 7.86 (d, J AB ) 7.9 Hz, 2H),
7.89 (dt, J ) 7.5 and 1.4 Hz, 1H), 8.03 (dd, J ) 7.7 and 1.4 Hz,
1H), 8.66 (dd, J ) 7.2 and 1.0 Hz, 1H). 13C NMR: δ 21.5, 28.0,
29.0, 67.1, 81.0, 117.1, 123.5, 128.3, 131.7, 132.2, 132.4, 136.1,
136.8, 138.5, 172.6, 176.4, 181.4. IR (KBr): 3279 (NH), 1632
(CdN), 1372 (SO2), 1310, 1215, 1180 (SO2), 1130, 1086, 976,
[2-(4,4-Dim eth yl-2-oxa zolin -2-yl)p h en yl]bis(4-m eth yl-
ph en yl)bism u th an e [(Tr iflu or om eth yl)su lfon yl]im ide (7).
Dichloride 6 (318 mg, 0.50 mmol) suspended in THF (15 mL)
was added to a suspension of TfNH2 (74.5 mg, 0.50 mmol) and
t-BuOK (112 mg, 1.0 mmol) in the same solvent (10 mL), and
the resulting mixture was stirred at room temperature for 1.5
h. The solvent was evaporated to dryness, and the residue
was extracted with CH2Cl2 (10 mL × 4). The combined
extracts were evaporated to one-tenth of the original volume,
and Et2O (10 mL) was added to the concentrate. The mixture
was stood at -15 °C to give the imide 7 as a colorless solid
(320 mg, 90%). Mp: 188-190 °C dec. 1H NMR: δ 0.68 (s,
6H), 2.38 (s, 6H), 4.10 (s, 2H), 7.36 (d, J AB ) 8.3 Hz, 4H), 7.76
(d, J AB ) 8.1 Hz, 4H), 7.74 (dt, J ) 7.7 and 1.0 Hz, 1H), 7.96
(dt, J ) 7.7 and 1.3 Hz, 1H), 8.12 (dd, J ) 7.6 and 1.5 Hz,
1H), 8.97 (d, J ) 7.8 Hz, 1H). 13C NMR: δ 21.4, 27.2, 67.8,
81.1, 118.5, 125.0, 130.0, 131.8, 132.0, 133.8, 135.3, 137.6,
141.8, 144.6, 148.2, 164.1. IR (KBr): 1642 (CdN), 1370 (SO2),
1254, 1204, 1159 (SO2), 1113, 1090, 988, 793, 613, 478 cm-1
Anal. Calcd for C26H26BiF3N2O3S: C, 43.83; H, 3.68; N, 3.93.
Found: C, 43.32; H, 3.62; N, 3.85.
.
Hyd r olysis of Im id e 7. The imide 7 (100 mg, 0.148 mmol)
in ethanol (15 mL) was heated under reflux for 2 h to give a
cloudy solution, which was filtered through a Celite bed. The
filtrate was evaporated to give a brown solid residue (86 mg),
which contained Tol3Bi (0.073 mmol, 49%), amidobismuthane
5 (0.050 mmol, 34%), and 2-(4,4-dimethyl-2-oxazolin-2-yl)-
benzene (0.098 mmol, 66%). The yields were based on imide
7, and the product ratio was estimated by 1H NMR. After
silica gel column chromatography using hexane-ethyl acetate
(10:1) as the eluent, Tol3Bi (36 mg, 0.074 mmol, 50%) was
obtained.
953, 729, 617 cm-1
. Anal. Calcd for C19H20BiF3N2O3S: C,
36.67; H, 3.24; N, 4.50. Found: C, 36.02; H, 3.19; N, 4.35.
[2-(4,4-Dim eth yl-2-oxa zolin -2-yl)p h en yl]bis(4-m eth yl-
p h en yl)bism u th Dich lor id e (6). A solution of bismuthane
3 (1.13 g, 2.0 mmol) in CH2Cl2 (10 mL) was added to a
suspension of PhICl2 (0.550 g, 2.0 mmol) in the same solvent
(10 mL) at 5 °C. The resulting mixture was stirred at this
temperature for 30 min and then concentrated under reduced
pressure to one-fifth of the original volume. Dilution of the
Th er m olysis of Im id e 7. Imide 7 (409 mg, 0.574 mmol)
was heated at 200 °C for 10 min under reduced pressure (1
mmHg) to form an orange solid, which was dissolved in CH2-

A Stabilized Triarylbismuthane Imide
Organometallics, Vol. 17, No. 6, 1998 1017
Ta ble 2. Selected Bon d Len gth s a n d An gles for
Im id e 7, w ith Estim a ted Sta n d a r d Devia tion s in
P a r en th eses
X-r a y Cr ysta llogr a p h y. Crystallographic data and details
of the data collection procedures and structure refinement for
imide 7 are presented in Table 1. Data were recorded on a
Rigaku AFC7S diffractometer, with graphite-monochromated
Mo KR radiation, using the ω-2θ scan technique. Azimuthal
scans of several reflections indicated no need for an absorption
correction. The data were corrected for Lorentz and polariza-
tion effects. No decay correction was applied. Structure
solution and refinement were carried out by use of the
Patterson method (DIRDIF92 PATTY)20 and full-matrix least
squares. The non-hydrogen atoms were refined anisotropi-
cally. Hydrogen atoms were included but not refined. Selected
intramolecular distances and angles are summarized in Table
2. Further details of the crystal structure investigation have
been deposited at Cambridge Crystallographic Data Centre
(CCDC), Cambridge, U.K.
Bond Lengths (Å)
Bi-N(1)
Bi-C(12)
S-O(1)
S-N(1)
Bi-O(1)
2.13(1)
2.19(1)
1.45(1)
1.53(1)
2.97(1)
Bi-C(1)
Bi-C(19)
S-O(2)
2.23(1)
2.20(2)
1.43(1)
2.69(1)
Bi-N(2)
Bond Angles (deg)
N(1)-Bi-C(1)
N(1)-Bi-C(19)
C(1)-Bi-C(19)
O(1)-S-O(2)
O(2)-S-N(1)
O(2)-S-C(26)
Bi-N(1)-S
94.2(5)
105.9(5)
112.0(5)
116.7(7)
114.4(7)
102.5(9)
111.0(6)
106.0(3)
163.5(4)
N(1)-Bi-C(12)
C(1)-Bi-C(12)
C(12)-Bi-C(19)
O(1)-S-N(1)
O(1)-S-C(26)
N(1)-S-C(26)
C(1)-Bi-N(2)
C(19)-Bi-N(2)
107.8(5)
113.4(5)
119.9(5)
114.3(7)
100.4(9)
106.1(8)
69.3(5)
C(12)-Bi-N(2)
N(1)-Bi-N(2)
82.1(5)
Ack n ow led gm en t. We acknowledge support of this
work by a Grant-in-Aid for J SPS Fellows (No. 6710)
from the Ministry of Education, Science, Sports and
Culture of J apan. T.I. thanks the J apan Society for the
Promotion of Science for a Fellowship (No. 6710).
Cl2 (30 mL); this solution was filtered through a Celite bed to
remove insoluble materials. The filtrate was evaporated to
give a brown residue (359 mg), which was revealed by 1H
NMR, using dibenzyl as an internal standard, to contain 62%
(0.358 mmol) of amidobismuthane 5.
NMR Mon itor in g of th e Oxid a tion of Ben zop in a col
w ith Im id e 7. Imide 7 (43 mg, 0.060 mmol), benzopinacol
(20 mg, 0.055 mmol), and dibenzyl (20 mg, 0.11 mmol) were
dissolved in CDCl3 (0.7 mL), and the reaction was monitored
by 1H NMR at 25 °C. After 1 h the starting materials
remained unchanged. After 12 h, imide 7 (27%), benzopinacol
(32%), and amidobismuthane 5 (63%) had been formed. After
24 h, benzopinacol was consumed, and imide 7 (4%), amidobis-
muthane 5 (0.053 mmol, 89%), toluene (0.054 mmol, 45%), and
benzophenone (0.108 mmol, 98%) were obtained. The yields
were estimated by NMR spectroscopy, using dibenzyl as an
internal standard.
Su p p or tin g In for m a tion Ava ila ble: Tables of X-ray
data, atomic coordinates and thermal parameters, and bond
distances and angles (15 pages). Ordering information is given
on any current masthead page.
OM970996V
(20) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.;
Garcia-Granda, S.; Gould, R. O.; Smits, J . M. M.; Smykalla, C.
Technical Report of the Crystallography Laboratory; University of
Nijmegen, Nijmegen, The Netherlands, 1992.