Synthesis, structures, and reactivity of biphenylylene complexes of bismuth(III)

Article abstract of DOI:10.1021/om950734y

The synthesis of [Bi₂(biph)₃] (5) and [PPN]-[BiCl₂(biph)] (6) (biph = 2,2′-biphenylylene, PPN = Ph₃P=N=PPh₃), the first structurally characterized biphenylylene complexes of bismuth (III), are described. Complex 5 crystallizes as a THF (tetrahydrofuran) solvate; each bismuth is three-coordinate with a trigonal pyramidal geometry. The solid state of 6 comprises separated [PPN]⁺ cations and [BiCl₂(biph)]^- anions. The anion adopts a trigonal bipyramidal geometry at the bismuth; the axial sites are occupied by chloride ligands, and two of the three equatorial sites are occupied by ring carbon atoms.

Full text of DOI:10.1021/om950734y

Organometallics 1996, 15, 887-890
887
Syn th esis, Str u ctu r es, a n d Rea ctivity of Bip h en ylylen e
Com p lexes of Bism u th (III)
Claire J . Carmalt,† Alan H. Cowley,*,‡ Andreas Decken,‡,§
Yvonne G. Lawson,† and Nicholas C. Norman*,†
Department of Chemistry, The University of Newcastle upon Tyne, Newcastle upon Tyne, NE1
7RU, U.K., and Department of Chemistry & Biochemistry, The University of Texas at Austin,
Austin, Texas 78712
Received September 14, 1995X
Sch em e 1
Summary: The synthesis of [Bi2(biph)3] (5) and [PPN]-
[BiCl2(biph)] (6) (biph ) 2,2′-biphenylylene, PPN )
Ph3PdNdPPh3), the first structurally characterized
biphenylylene complexes of bismuth (III), are described.
Complex 5 crystallizes as a THF (tetrahydrofuran)
solvate; each bismuth is three-coordinate with a trigonal
pyramidal geometry. The solid state of 6 comprises
separated [PPN]+ cations and [BiCl2(biph)]- anions. The
anion adopts a trigonal bipyramidal geometry at the
bismuth; the axial sites are occupied by chloride ligands,
and two of the three equatorial sites are occupied by ring
carbon atoms.
In tr od u ction
In a recent series of papers1-4 we have described the
results of a number of crystal structure determinations
for a range of arylbismuth(III) halides and halogeno
anions, from which a number of structural trends have
emerged. In contrast to the structures now known for
aryl- (mostly phenyl) bismuth compounds, however,
there are few structurally characterized examples of
linked aryl or heteroaromatic bismuth derivatives.
Recently, Suzuki et al.5 reported the structure of 10-
((4′-chlorophenyl)ethynyl)phenothiabismin 5,5-dioxide
(1), in which the bismuth center adopts a three-
coordinate, trigonal pyramidal coordination geometry.
However, additional interactions are present between
the bismuth atom and the sulfonyl oxygen atoms. The
structure of a biphenylylene complex of antimony(III),
[SbCl(biph)] (2), has also been described recently.6 In
compound 2, the primary coordination environment of
the antimony atom is trigonal pyramidal, but additional
secondary Sb‚‚‚Cl interactions are also present resulting
in the formation of loosely bound dimers. Biphenylylene
complexes of bismuth(III) have not hitherto been struc-
turally characterized, but analytical data have been
presented for [BiI(biph)]7 and [PhBi(biph)]8 as well as
for the bismuth(V) complex [Ph3Bi(biph)].9 Herein we
report the syntheses of a range of biphenylylene com-
plexes of bismuth(III), two examples of which have been
characterized by X-ray crystallography.
Resu lts a n d Discu ssion
The reaction between BiCl3 and 1 equiv of 2,2′-
dilithiobiphenyl‚TMEDA10 (3) (TMEDA ) N,N,N′,N′-
tetramethylethylenediamine) in Et2O solution afforded,
after workup, a cream colored crystalline solid, analyti-
cal data for which (Table 1) were consistent not with
the expected formula [BiCl(biph)] (4) (biph ) 2,2′-
biphenylylene) but with the formula [Bi2(biph)3] (5). As
indicated in Scheme 1, 5 presumably results either from
the reaction of 4 with 3 or via a redistribution reaction
of 4. Redistribution reactions of this type have been
found to be characteristic of arylbismuth halide com-
pounds in solution.1-4 However, it is also of interest to
note (ref 7) that analytical data have been presented
for the related antimony complex, [Sb2(biph)3], which
results from the reaction of [SbI(biph)] with Li2-
(biphenyl). Moreover, compound 5 was obtained in
higher yield from the stoichiometrically correct reaction
between 2 equiv of BiCl3 and 3 equiv of 3 in Et2O
solution.
† The University of Newcastle upon Tyne.
‡ The University of Texas at Austin.
§ Present address: Chemistry Department, University of New
Brunswick, Bag Service 45222, Fredericton, New Brunswick, Canada
E3B 6E2.
X Abstract published in Advance ACS Abstracts, December 15, 1995.
(1) Clegg, W.; Errington, R. J .; Fisher, G. A.; Hockless, D. C. R.;
Norman, N. C.; Orpen, A. G.; Stratford, S. E. J . Chem. Soc., Dalton
Trans. 1992, 1967.
(2) Clegg, W.; Errington, R. J .; Fisher, G. A.; Flynn, R. J .; Norman,
N. C. J . Chem. Soc., Dalton Trans. 1993, 637.
(3) Clegg, W.; Elsegood, M. R. J .; Errington, R. J .; Fisher, G. A.;
Norman, N. C. J . Mater. Chem. 1994, 4, 891.
(4) Carmalt, C. J .; Cowley, A. H.; Decken, A.; Norman, N. C. J .
Organomet. Chem. 1995, 496, 59.
(5) Suzuki, H.; Murafuji, T.; Azuma, N. J . Chem. Soc., Perkin Trans.
1992, 1593.
(6) Millington, P. L.; Sowerby, D. B. J . Organomet. Chem. 1994, 480,
227.
(7) Hellwinkel, D.; Bach, M. J . Organomet. Chem. 1969, 17, 389.
(8) Wittig, G.; Hellwinkel, D. Chem. Ber. 1964, 97, 789.
(9) Hellwinkel, D.; Bach, M. Liebigs Ann. Chem. 1968, 720, 198.
(10) Neugebauer, W.; Kos, A. J .; Schleyer, P. v. R. J . Organomet.
Chem. 1982, 228, 107.
0276-7333/96/2315-0887$12.00/0 © 1996 American Chemical Society

888 Organometallics, Vol. 15, No. 2, 1996
Ta ble 1. NMR a n d An a lytica l Da ta
Notes
elemental anal.a
H
compd
δ(1H)b
δ(13C{1H})b
C
N
5
8.19 (m, 2H), 8.14 (m, 2H),
7.95 (m, 2H), 7.87 (m, 2H),
7.62-7.71 (m, 8H), 7.53-7.61
(m, 6H), 7.39 (m, 2H)
C-H carbons, 139.1, 138.9, 138.8,
131.5, 131.4, 129.6, 129.4, 129.2,
129.0, 128.8, 127.8, 127.7; C-C and
C-Bi carbons, 160.0, 159.6, 153.0
C-H carbons, 140.7, 133.0, 132.2,
130.8; C-C and C-Bi carbons;
197.6, 165.4
C-H carbons (biph), 140.5, 132.7,
131.7, 130.7; C-C or C-Bi carbons
(biph), 195.4, 165.3; 137.7 (s, p-C6H5,
PPN), 136.0 (m, o/m-C6H5, PPN),
133.5 (m, o/m-C6H5, PPN), 130.8
(d, i-C6H5, PPN, J PC ) 108 Hz)
50.10 (50.40) 3.30 (3.40)
product of the reacn 8.36 (d, 2H, J ) 7.2 Hz), 8.25
25.60 (28.70) 2.10 (1.60)
of 5 with BiCl3
(d, 2H, J ) 7.8Hz), 7.73 (t, 2H,
J ) 7.2 Hz), 7.61 (t, 2H, J ) 7.5 Hz)
8.23 (d, 2H, J ) 7.1 Hz), 8.18 (d, 2H,
J ) 7.7 Hz), 7.81 (m, 6H, p-C6H5),
7.62-7.72 (m, 26H, o,m-C6H5,
7
59.10 (59.40) 3.90 (3.95) 1.50 (1.45)
and 2H, biph), 7.54 (t, 2H, J ) 7.4 Hz)
a
b
Calculated values in parentheses. Referenced to TMS (Me4Si), with positive values to high frequency. All spectra were obtained in
DMSO-d6 (dimethyl-d6 sulfoxide).
Ta ble 2. Selected Bon d Len gth s a n d An gles for 5
Bond Lengths (Å)a
Bi(1)-C(1)
Bi(1)-C(13)
Bi(2)-C(36)
2.272(12)
2.284(9)
2.227(10)
Bi(1)-C(12)
Bi(2)-C(25)
Bi(2)-C(36)
2.225(12)
2.233(12)
2.279(10)
Bond Angles (deg)a
C(1)-Bi(1)-C(12)
C(12)-Bi(1)-C(13)
C(25)-Bi(2)-C(24)
C(11)-C(12)-Bi(1) 124.9(11) C(7)-C(12)-Bi(1)
C(14)-C(13)-Bi(1) 122.3(8)
C(6)-C(1)-Bi(1) 112.6(8)
78.2(5)
90.9(4)
93.9(4)
C(1)-Bi(1)-C(13)
C(25)-Bi(2)-C(36)
C(36)-Bi(2)-C(24)
92.6(4)
77.6(4)
95.5(4)
112.1(9)
C(18)-C(13)-Bi(1) 118.6(7)
C(2)-C(1)-Bi(1) 129.1(10)
C(19)-C(24)-Bi(2) 117.7(7)
C(35)-C(36)-Bi(2) 127.4(9)
C(30)-C(25)-Bi(2) 113.4(8)
C(23)-C(24)-Bi(2) 122.8(8)
C(31)-C(36)-Bi(2) 112.4(8)
C(26)-C(25)-Bi(2) 125.2(8)
F igu r e 1. View of the molecular structure of 5 showing
the atom-numbering scheme.
a
Esd’s given in parentheses.
one of THF per asymmetric unit. Both bismuth centers
adopt a three-coordinate, trigonal pyramidal coordina-
tion geometry (sums of angles at Bi(1) and Bi(2) ) 261.7-
(5) and 267.4(4)°, respectively). The Bi-C distances
[average 2.253(12) Å] fall within the range reported for
other Bi(III) aryl derivatives.1-4 The C-Bi-C angles
fall into two distinct ranges, namely 78.2(5)-77.6(4) and
90.9(4)-95.9(4)°. The smaller values relate to the
endocyclic angles and result from the constraints of the
chelating biph ligand. The C4Bi rings are both planar
within experimental error, and the largest deviations
from the mean plane were found to be 0.025 Å for Bi(1)
and 0.046 Å for Bi(2). Both values are similar to that
reported for 2 (0.03 Å). The longer, exocyclic C-Bi-C
bond angles in 5 are comparable to those reported for
BiPh3 which span the range 92-96°.11 The torsion
angle about the C(18)-C(19) bond, in the central biph
ligand, is 80.0(13)° thus indicating a large degree of
twist about this bond. The intermolecular Bi‚‚‚Bi
contacts in 5 are 4.7 Å (Figure 2).
As a further point of discussion, we note that mol-
ecules of 5 possess approximate C2 symmetry and are
therefore chiral. As in the case of other substituted
biphenyl compounds with bulky substituents at the 2
and 2′ positions, this structural feature arises because
of the inhibition of free rotation about the central
biphenyl C-C bond.12 The chirality of 5 is also evident
in the 1H and 13C{1H} NMR spectra (Table 1). Note that
12 C-H resonances are observed as a consequence of
the inequivalence of the terminal biphenylylene groups.
F igu r e 2. View of part of the crystal structure of 5
showing the Bi‚‚‚Bi contacts.
The structure of 5 was established by X-ray crystal-
lography, the results of which are shown in Figures 1
and 2. Selected bond lengths and angles are given in
Table 2. As well as confirming the proposed formula
for 5, the X-ray study revealed that this compound
crystallizes as a THF solvate with one molecule of 5 and
(11) Hawley, D. M.; Ferguson, G. J . Chem. Soc. A 1968, 2059.
(12) For a further discussion of this matter, see: March, J . Advanced
Organic Chemistry: Reactions, Mechanisms and Structure, 2nd ed.;
McGraw-Hill: Kogakusha, Tokyo, 1977; pp 92-94.

Notes
Organometallics, Vol. 15, No. 2, 1996 889
F igu r e 3. View of the molecular structure of 6- showing
the atom-numbering scheme.
Sch em e 2
F igu r e 4. View of the packing of the cations and anions
in 6.
Ta ble 3. Selected Bon d Len gth s a n d An gles for 6
Bond Lengths (Å)a
trigonal bipyramidal or disphenoidal coordination en-
vironment. The chloride ligands adopt axial sites, and
the Bi-Cl(1) and Bi-Cl(2) bond distances are 2.702(2)
and 2.743(2) Å, respectively. The Cl(1)-Bi-Cl(2) bond
angle is 175.10(7)°. Although this is a small departure
from linearity, it is interesting to note that contrary to
VSEPR arguments the chloride ligands point away from
rather than toward the biph ligand.13 The biph ligand
occupies two equatorial positions, and the Bi-C bond
distances [Bi-C(4a) 2.256 Å and Bi-C(5a) 2.230 Å] fall
within the usual range.1-4 The fact that the C(1)-Bi-
C(12) bond angle [77.6(3)°] is apprecially less than the
ideal value of 120° is attributable to the chelating nature
of the biph ligand; comparable acute angles are also
evident in 5. The C4Bi ring is planar within experi-
mental error, the mean deviation being 0.024 Å. In the
related complex [PPh4][BiBr2Ph2],1 the bismuth center
in the anion adopts a similar structure, the only
significant difference being the larger unconstrained
angle between the equatorial carbon atoms [95.9(1)°].
Bi-Cl(1)
Bi-C(1)
2.702(2)
2.256(8)
Bi-Cl(2)
Bi-C(12)
2.743(2)
2.230(8)
Bond Angles (deg)a
Cl(1)-Bi-Cl(2)
C(1)-Bi-Cl(1)
C(12)-Bi-Cl(1)
C(2)-C(1)-Bi
C(7)-C(12)-Bi
175.10(7)
92.2(2)
89.5(2)
126.5(7)
112.7(5)
C(1)-Bi-C(12)
C(1)-Bi-Cl(2)
C(12)-Bi-Cl(2)
C(6)-C(1)-Bi
C(11)-C(12)-Bi
77.6(3)
90.4(2)
87.0(2)
111.7(5)
126.6(6)
a
Esd’s given in parentheses.
In an effort to intercept and isolate the desired
benzannelated chlorobismole 4, complex 5 was treated
with an equimolar quantity of BiCl3 in Et2O solution
(Scheme 2). The 1H and 13C{1H} NMR data for the
resulting cream colored solid (Table 1) indicated that a
pure product was formed and were supportive of the
proposed formulation, [BiCl(biph)] (4). However, the
analytical data for this product were low for both carbon
and hydrogen indicating that pure 4 is not formed
possibly because it is contaminated with BiCl3. At-
tempts to isolate pure 4 were unsuccessful even under
high-dilution conditions. Further treatment of this
mixture with an excess of [PPN]Cl (PPN ) Ph3PdNd
PPh3) afforded, after recrystallization from MeCN/Et2O
mixtures, colorless crystals of the salt [PPN][BiCl2-
(biph)] (6). The proposed formulation for 6 was consis-
tent with pertinent analytical and spectroscopic data
(Table 1). However, in order to confirm the structure,
it was necessary to appeal to X-ray crystallography. The
solid state of 6 consists of [PPN]+ cations and
[BiCl2(biph)]- anions (henceforth referred to as 6-) and
there are no unusually short interionic contacts. The
structure of 6- is illustrated in Figure 3, and selected
bond distances and angles are given in Table 3. A view
of the packing of the anions and cations in 6 is presented
in Figure 4. The structure of 6- comprises a four-
coordinate bismuth center with an equatorially vacant,
Exp er im en ta l Section
Gen er a l P r oced u r es. All reactions were performed using
standard Schlenk techniques under an atmosphere of dry,
oxygen-free dinitrogen. All solvents were distilled from ap-
propriate drying agents immediately prior to use (sodium-
benzophenone for Et2O and THF, CaH2 for CH2Cl2, and sodium
for hexanes). The halides, BiBr3 (99%+), BiCl3 (99%+), [PPN]-
Cl, and [Ph4P]Br were procured commercially and used
without further purification; 2,2′-dilithiobiphenyl‚2TMEDA10
(3) was prepared according to the literature method. Mi-
croanalytical data were obtained at The University of New-
castle upon Tyne. 1H and 13C{1H} NMR spectra were recorded
(13) For other cases where VSEPR arguments are not in accord with
all structural details, see: (a) Hall, M.; Sowerby, D. B. J . Organomet.
Chem. 1988, 347, 59. (b) Calderazzo, F.; Marchetti, F.; Ungari, F.;
Wieber, M. Gazz. Chim. Ital. 1991, 121, 93.

890 Organometallics, Vol. 15, No. 2, 1996
Notes
Ta ble 4. Cr ysta llogr a p h ic a n d Str u ctu r e Solu tion Da ta for Com p ou n d s 5 a n d 6
5
6
compd formula
Mr
C36H24Bi2‚C4H8O
946.62
C48H38BiCl2NP2
970.6
space group
P21/c
C2/c
cryst system
monoclinic
13.861(2)
17.059(2)
14.681(1)
115.098(8)
3143.6(6)
4
monoclinic
35.430(5)
8.962(1)
27.321(3)
93.07(1)
8663(3)
a/Å
b/Å
c/Å
â/deg
V/Å3
Z
8
D
calc/g cm-3
2.000
1.488
F(000)
1784
112.12
183(2)
3840
43.01
293(2)
µ(Mo KR)/cm-1
T/K
scan mode
ω
θ/2θ
θ range/deg
cryst size/mm
range of transm
coeff
2.01 < θ < 27.50
0.191 × 0.27 × 0.50
0.113-0.453
2.30 < θ < 24.97
0.18 × 0.19 × 0.67
0.299-0.724
no. of data collcd
no. of unique data
hkl range
14 430
7222
17 353
7617
-18 f 18, 0 f 22, -19 f 19
391
0.0567
0.1313
-42 f 42, -10 f 1, -32 f 32
489
0.0483
0.1246
no. of refined params
Final R
2
Final Rw
goodness of fit, S
1.021
1.115
largest remaining feature
in electron density mapa/e Å-3
shift/esd in last cycle
+2.891 (max), -2.725 (min)
+2.221 (max), -0.867 (min)
0.001 (max), 0.000 (av)
0.001 (max), 0.000 (av)
a
Found near Bi atoms.
on Bruker WP200 and WM500 spectrometers, and 31P NMR
spectra were measured on a J EOL FX90Q spectrometer.
Syn th esis of [Bi2(bip h )3] (5). An orange solution of 3
(3.426 g, 8.57 mmol) in Et2O (40 mL) was added to a stirred
solution of BiCl3 (2.697 g, 8.55 mmol) in Et2O (30 mL) at -78
°C. A precipitate formed immediately, and after being stirred
for 30 min, the reaction mixture was allowed to warm to room
temperature. The mixture was stirred overnight and then
filtered through Celite. The volume of the resulting pale
yellow solution was reduced to about half, and after a period
of days at -22 °C, 0.801 g of cream colored crystalline 5 was
isolated (20% yield based on bismuth).
Compound 5 was also made in higher yield by treatment of
2 equiv of BiCl3 with 3 equiv of 3. For example, the reaction
between BiCl3 (0.222 g, 0.704 mmol) and 3 (0.422 g, 1.054
mmol) was carried out as above and afforded 0.335 g of 5 after
workup (50% yield based on bismuth).
Rea ction of 5 w ith BiCl3. A solution of BiCl3 (0.143 g,
0.452 mmol) in Et2O (6 mL) was added to a stirred solution of
5 (0.300 g, 0.452 mmol) in Et2O (10 mL) at room temperature
resulting in the formation of a pale yellow precipitate. After
stirring of the reaction mixture for approximately 30 min, the
supernatant liquid was removed by syringe. Removal of the
solvent and volatiles under vacuum left 0.315 g of cream
colored solid. Analytical and NMR data for this product are
summarized in Table 1.
Syn th esis of [P P N][BiCl2(bip h )] (6). A sample of the
product obtained in the previous reaction (0.104 g) and [PPN]-
Cl (0.168 g, 0.292 mmol) were dissolved in THF (15 mL), and
the resulting mixture was stirred for 24 h, after which time
the reaction flask contained a cloudy white solution. The
solvent and volatiles were removed under reduced pressure,
the resulting white solid was dissolved in hot CH3CN (7 mL),
and Et2O (20 mL) was added as an overlayer after allowing
the CH3CN solution to cool to room temperature. Solvent
diffusion over a period of days at room temperature afforded
colorless crystals of 6 (0.097 g, 70%), one of which was used
for X-ray crystallography.
X-r a y Cr ysta llogr a p h y. Crystallographic data and details
of the data collection procedures and structure refinement for
5 and 6 are presented in Table 4. The following section deals
with the structure of 5 with details for the structure of 6, where
different, given in brackets. Data were collected on an Enraf-
Nonius CAD4 diffractometer [Nicolet P3 for 6] with graphite-
monochromated X-radiation (λ ) 0.710 73 Å). Accurate unit
cell parameters were determined by recentering 25 optimal
high-angle reflections. Three standard reflections were mea-
sured every 1 h [four in every 96 reflections for 6] during data
collection, and no decrease in intensities was noted. Correc-
tions were applied for Lorentz-polarization and absorption
effects. The structure was solved for the heavy atoms by direct
methods (SHELXL PLUS).14 Subsequent difference syntheses
gave all other non-hydrogen atomic positions. All non-
hydrogen atoms were allowed anisotropic thermal motion.
Hydrogen atoms were included at calculated positions (C-H
0.96 Å) and were refined using a riding model and a general
isotropic thermal parameter. Refinement was by full-matrix
least squares on F2.
Ack n ow led gm en t. We thank the SERC for a stu-
dentship (C.J .C.) and NATO for an International Col-
laborative Research Grant. N.C.N. also thanks the
Royal Society for additional supporting funds. A.H.C.
thanks the National Science Foundation and the Robert
A. Welch Foundation for financial support.
Su p p or tin g In for m a tion Ava ila ble: Table of X-ray
parameters, atom coordinates, thermal parameters, and bond
distances and angles and ORTEP diagrams (18 pages). Order-
ing information is given on any current masthead page.
OM950734Y
(14) Sheldrick, G. M. SHEXTL-PLUS, Siemens Analytical X-ray
Instruments, Inc. Go¨ttingen, 1990.