Reactions of terphenylbismuth dihalides with KSi(SiMe3) 3, K2Si2(SiMe3)4 and Na2[Fe(CO)]4: Reduction vs. metathesis

Article abstract of DOI:10.1002/ejic.200701334

The reactions of terphenylbismuth dihalides with various reducing agents were investigated. Attempted metathesis of Ar′BiCl₂ [Ar′ = 2,6-(2,6-iPr₂-C₆H₃)₂-C ₆H₃] with one equivalen

Full text of DOI:10.1002/ejic.200701334

FULL PAPER
DOI: 10.1002/ejic.200701334
Reactions of Terphenylbismuth Dihalides with KSi(SiMe3)3, K2Si2(SiMe3)4 and
Na2[Fe(CO)]4: Reduction vs. Metathesis
Robert Wolf,[a] Jelena Fischer,[a] Roland C. Fischer,[a] James C. Fettinger,[a] and
Philip P. Power*[a]
Keywords: Bismuth / Terphenyl / Silicon / Iron
The reactions of terphenylbismuth dihalides with various re-
ducing agents were investigated. Attempted metathesis of
[Fe(CO)4(Bi2ArЈ2)] (3) and [Fe(CO)4(Bi2Ar#2)] (4) in modest
yields (25 and 15% respectively). The compounds 1–4 were
ArЈBiCl2 [ArЈ = 2,6-(2,6-iPr2-C6H3)2-C6H3] with one equiva- characterized by X-ray crystallography and by spectroscopic
lent of KSi(SiMe3)3 gave the 1,2-dichlorodibismuthane
ArЈ(Cl)Bi–Bi(Cl)ArЈ (1) in 40% yield. The reaction of ArЈBiCl2
(1) with the dianionic salt K2Si2(SiMe3)4 yielded the dibismu-
thene ArЈBi=BiArЈ (2) in 72%. The terphenylbismuth di-
halides ArBiCl2 [Ar = 2,6-(2,6-iPr2-C6H3)2-C6H3 (ArЈ), 2,6-
(2,4,6-Me3-C6H2)2-C6H3 (Ar#)] were treated with Na2[Fe-
(CO)4] in THF to afford the iron dibismuthene complexes
methods (1H and 13C NMR, IR, and UV/Vis spectroscopy).
The results show that reduction of the bismuth center is
strongly preferred over salt metathesis chemistry due to the
reducing power of the silanide and ferrate salts and the
strength of the Bi=Bi bond.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2008)
ration of a homologous series of stable, heavier dipnictenes
RE=ER (E = P, As, Sb and Bi).[11] Herein, we report our
attempts to exploit the beneficial properties of these ligands
for the preparation of novel bismuth–silicon and bismuth–
iron compounds that exhibit new bonding motifs. These in-
vestigations have yielded novel Bi–Bi bonded products via
the reduction of the terphenylbismuth dichloride starting
material. Thus, the reaction of ArЈBiCl2 [ArЈ = 2,6-(2,6-
iPr2-C6H3)2-C6H3] with KSi(SiMe3)3 and K2Si2(SiMe3)4 led
not to silylbismuth species but to the dibismuthane ArЈ(Cl)-
Bi–Bi(Cl)ArЈ (1) and the new dibismuthene ArЈBi=BiArЈ
(2), respectively. Reactions of ArBiCl2 (Ar = ArЈ and Ar#)
with Na2[Fe(CO)4] yielded the first iron–dibismuthene com-
plexes [Fe(CO)4(Bi2ArЈ2)] (3) and [Fe(CO)4(Bi2Ar#2)] (4).
Introduction
The discovery of the first stable diphosphene,
Mes*P=PMes* (Mes* = 2,4,6-tBu3-C6H2), by Yoshifuji and
co-workers in 1981 was a landmark achievement which was
rapidly followed by extensive reactivity and spectroscopic
studies of diphosphenes and their heavier congeners.[2–5]
Numerous transition metal complexes of diphosphenes
with unsupported phosphorus – phosphorus double bonds
such as [{Fe(CO)4}-trans-(P2R2)] (R = bulky organic
group)[7] are known and these complexes illustrate the ver-
satility of diphosphenes as ligands.[6–9] In contrast, Bi=Bi
double bonds were only experimentally authenticated in
1997 when Tokitoh and co-workers reported the synthesis
of the aryl dibismuthene TbtBi=BiTbt (Tbt = C6H2-2,4,6-
{CH(SiMe3)2}3).[10] Soon after, other dibismuthenes featur-
ing the related aryl substituents Ar# = 2,6-(2,4,6-Me3-
C6H2)2-C6H3 or Ar* = 2,6-(2,4,6-iPr3-C6H2)2-C6H3, were
reported.[11] At present, stable examples of dibismuthenes,
either as complexed or uncomplexed entities, remain ex-
tremely rare[11–14] while compounds with a double bond be-
tween bismuth and another p-block element are limited to
Mes*P=BiTbt[15] and TbtSb=BiTbt.[16]
Results and Discussion
Syntheses and Structures of ArЈ(Cl)BiBi(Cl)ArЈ (1) and
ArЈBi=BiArЈ (2)
In order to access the hypothetical silylbismuth com-
pound ArЈBiCl(Si{SiMe3}3), a possible precursor for a
Bi=Si double bond, we attempted the reaction of the steri-
Bulky terphenyl ligands such as Ar# and Ar*[17] have
proven very useful in the stabilization of new types of
metal–metal multiple bonds[18] and have enabled the prepa-
cally encumbered arylbismuth dichloride ArЈBiCl2 with the
[19]
bulky silanide KSi(SiMe3)3
(Scheme 1, a). However, in
place of the intended salt metathesis reaction, we observed
a redox process which led to the formation of the singly
bonded dibismuthane ArЈ(Cl)BiBi(Cl)ArЈ (1). In a similar
manner, the reaction of ArЈBiCl2 with the disilane-1,2-diide
K2Si2(SiMe3)4[20] was carried out with the aim of producing
[a] University of California, Davis
One Shields Ave, Davis, CA 95616, USA
Fax: +1-530-752-8995
E-mail: pppower@ucdavis.edu
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R. Wolf, J. Fischer, R. C. Fischer, J. C. Fettinger, P. P. Power
FULL PAPER
Scheme 1.
unusual cyclic compounds such as cyclo-(BiArЈSi2{SiMe3}4) tances ranging from 2.983(8) to 3.2092(8) Å.[12,23,24] The
or cyclo-(BiArЈSi2{SiMe3}4)2.[21] However, as seen for the Bi–Bi bond length in 1 is thus in the expected range. Similar
reaction of KSi(SiMe3)3, the reduction of ArЈBCl2 with to other dibismuthanes[12,23] 1 displays a strictly anti-
K2Si2(SiMe3)4 transpired to give the dibismuthene ArЈBi= periplanar conformation. The terphenyl ligands ArЈ are al-
BiArЈ (2) in a 72% yield (Scheme 1, b). Analysis of the most co-planar (C2–C1–Bi1–Bi1a torsion angle: –175°),
mother liquors from the above reactions further supported leading to the close approach of the flanking 2,6-iPr2-C6H3
the presence of redox chemistry. For example the synthesis substituents to a neighboring bismuth atom. Bismuth-arene
of 1 resulted in concomitant synthesis of (Me3Si)3SiSi- π-interactions have been observed previously,[25] nonethe-
(SiMe3)3. During the synthesis of 2 oxidation of K2Si2- less, the long Bi1-centroid distance of 3.283 Å indicates
(SiMe3)4 occurred to afford the unstable intermediate that, if such an interaction is present in 1, it is rather weak
(Me3Si)2SiSi(SiMe3)2 which is readily dimerized to give and is probably of relatively minor structural significance.
cyclo-{Si(SiMe3)2}4 as verfied by 29Si NMR spectroscopy. The steric effect of the large terphenyl ligands is apparent
Our present report thus underlines the potential of alkali in the bond angles around Bi1: while the two bond angles
metal silanides as benign and easily separable reducing
agents towards substituted bismuth halides. However, in re-
actions with pure bismuth halides reduction may not occur
and Linti and Köstler have observed that the cyclotetrabis-
muthane cyclo-(Bi4{SiMe3}4) featuring Bi–Si bonds can be
synthesized from BiBr3 and 3 equiv. of Li(THF)3(Si-
{SiMe3}3).[22]
The compounds 1 and 2 were characterized by X-ray
crystallography, 1H and 13C NMR and UV/Vis spec-
troscopy. The solid-state molecular structure of 1 (Figure 1,
Table 1) shows a mixed-substituted dibismuthane with a Bi–
Bi single bond length of 3.0232(4) Å. The aryl and chlorine
substituents adopt strictly trans arrangements which are
dictated by a crystallographic center of symmetry located
at the midpoint of the Bi–Bi vector. While the structure of
a heteroleptic dibismuthane such as 1 with two different
substituents on Bi has to the best of our knowledge not
been reported (nor, in fact, has an example of an antimony
analogue), a number of homoleptic compounds R2BiBiR2
have been structurally characterized and display Bi–Bi dis- (30% ellipsoid level, H-atoms are not shown for clarity).
Figure 1. Structure of ArЈ(Cl)Bi–Bi(Cl)ArЈ (1) in the solid state
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Reactions of Terphenylbismuth Dihalides
Table 1. Selected bond lengths [Å] and angles [°] of 1–4.
1
2
3
4
Bi(1)–Bi(1a)
Bi(1)–C(1)
C(1)–Bi(1)–Bi(1a)
C(2)–C(1)–Bi(1)–Bi(1a)
Bi(1)–Cl1
Cl(1)–Bi(1)–Bi(1a)
C(1)–Bi(1)–Cl(1)
3.0232(4)
2.297(5)
103.8(2)
–175.0
2.566(2)
84.62(5)
88.9(2)
2.8560(3)
2.327(2)
105.44(6)
180.0
Bi(1)–Bi(2)
Bi(1)–C(ipso)
Bi(2)–C(ipso)
Bi(1)–Bi(2)–C(ipso)
Bi(2)–Bi(1)–C(ipso)
C(ipso)–Bi(1)–Bi(2)–C(ipso)
Bi(1)–Fe(1)
Bi(2)–Fe(1)
av. Fe–C
2.9432(2)
2.337(2)
2.344(2)
106.73(6)
105.30(6)
161.68
2.8033(4)
2.8105(4)
1.805(3)
1.140(3)
58.262(8)
58.500(8)
63.238(8)
102.18(6)
100.16(6)
2.9294(2)
2.313(3)
2.302(3)
102.37(7)
101.50(7)
165.11
2.8248(5)
2.8058(5)
1.805(3)
1.142(4)
58.968(9)
58.33(1)
62.70(2)
102.24(7)
102.68(7)
av. C–O
Bi(1)–Bi(2)–Fe(1)
Bi(2)–Bi(1)–Fe(1)
Bi(1)–Fe(1)–Bi(2)
C(ipso)–Bi(1)–Fe(1)
C(ipso)–Bi(1)–Fe(1)
involving the chlorine atom are slightly narrower than 90°, 100.5(7)° respectively. The Bi–Bi distance in 2 also exceeds
the C1–Bi1–Bil a angle of 103.5(2)° is widened due to the the 2.8377(7) Å[4] found in the unsubstituted dianion
large size of the ArЈ substituent.
[Bi2]2– where a relatively short Bi–Bi double-bonded dis-
The solid-state structure of 2 (Figure 2, Table 1) re- tance is observed in spite of the electronic repulsion.[27]
sembles the only two other structurally characterized un- Interestingly, the conformation of 2 also differed from that
complexed dibismuthenes in that it has a trans-bent core observed in the previously synthesized dibismuthenes; thus
structure.[10,11,26] The molecule resides on a crystallographic in Ar#Bi=BiAr# and TbtBi=BiTbt, the central aryl rings
centre of symmetry and displays a strictly anti-periplanar, are nearly perpendicular to the Bi–Bi bond axis, whereas
trans-bent geometry of the C–Bi–Bi–C core. The Bi–Bi the central aryl rings in 2 are approximately coplanar
bond length of 2.8560(3) Å is significantly (5.5%) shorter (Bi1a–Bi1–C1–C2 –8.9°). As in 1, weak contacts were ob-
than the Bi–Bi distance in ArЈ(Cl)Bi–Bi(Cl)ArЈ (1) which served between Bi and the flanking aryl rings of the ArЈ
is consistent with the presence of double bond character. substituent (Bi1–centroid: 3.328 Å).
1
However, this distance is slightly longer than the values
The H NMR spectra of 1 and 2 are in agreement with
found in the related compounds TbtBi=BiTbt [2.8206(8) Å, the centrosymmetric structures observed in the solid state
Tbt = 2,4,6-{CH(SiMe3)2}3-C6H2[10]] and Ar#Bi=BiAr# and indicate the presence of magnetically equivalent 2,6-
[2.833(2) Å].[11] This small difference may be a consequence iPr2-C6H3 substituents with diastereotopic methyl groups.
of the higher steric repulsion between the much larger ArЈ The UV/Vis spectrum of 2 spectrum displays a maximum
ligands in 2. The increased crowding may also cause the absorption at 526 nm which corresponds well to the absorp-
quite wide Bi1a–Bi1–C1 angle of 105.44(6)° observed for 2, tions at 505 nm and 518 nm observed previously for the re-
which may be compared to the corresponding angles within lated π-π* transitions in the diaryl dibismuthenes Ar#Bi=
Ar#Bi=BiAr# and TbtBi=BiTbt which are 92.5(4) and BiAr# and Ar*Bi=BiAr*.[11]
Syntheses and Structures of [Fe(CO)4(Bi2ArЈ2)] (3) and
[Fe(CO)4(Bi2Ar#2)] (4)
Cassidy and Whitmire have reported that the dinuclear
complex [Fe(CO)4(BiPh)]2 is formed from the reaction of
Collman’s reagent, Na2[Fe(CO)4], with two equiv. of
Ph2BiCl or one equiv. of PhBiBr2, respectively.[28] In order
to investigate the steric effects of a very bulky aryl substitu-
ent on such a transformation we reacted Na2[Fe(CO)4][29]
and ArBiCl2 (Ar = ArЈ and Ar#, Scheme 1, c) and obtained
the complexes 3 and 4 as dark-red, crystalline solids in
modest yields (15% and 25%). Both compounds were char-
acterized by NMR, UV/Vis and IR spectroscopy. Interest-
ingly, compounds 3 and 4 appear to be air-stable as solids
for several days, although significant quantities of ArBi=
BiAr (Ar = ArЈ or Ar#, respectively) were observed in the
1H NMR spectra after storing C6D6 solutions of 3 and 4 at
room temperature for several weeks. X-ray crystallographic
studies revealed very similar structures for both compounds
Figure 2. Solid-state structure of ArЈBi=BiArЈ (2) (30% ellipsoid
level, H-atoms are not shown for clarity).
Eur. J. Inorg. Chem. 2008, 2515–2521
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R. Wolf, J. Fischer, R. C. Fischer, J. C. Fettinger, P. P. Power
FULL PAPER
Figure 3. Solid-state molecular structure of [Fe(CO)4(Bi2Ar#2)] (3) (left image) and [Fe(CO)4(Bi2ArЈ2)] (4) (right image, H-atoms are not
shown for clarity, thermal ellipsoids at the 30% probability level, toluene solvent molecules not shown).
which contain ArBi=BiAr dibismuthene units in a trans ar- longer end of the range observed in other Bi–Fe clusters
rangement coordinated to an Fe(CO)4 moiety in a symmet- containing iron carbonyl fragments.[31] Finally, it should be
rical η2-fashion (Figure 3, Table 1). The structures resemble noted that the different steric demand of the flanking aryl
that of the distibene complex [Fe(CO)4(Sb2R2)] (R = rings has only a very minor effect on the overall structures
CH(SiMe3)2), which was prepared by a similar route to 3 of 3 and 4. In 3, the Bi–Bi and Bi–C bonds are slightly
and 4 and has an Sb–Sb bond length of 2.774(1) Å.[30] The longer and the Bi–Bi–C angles are marginally wider which
dibismuthenes in 3 and 4 are bound “face-on” to the is in accord with larger bulk of the aryl substituents. How-
Fe(CO)4 moiety which produces an out of plane bending of ever, although the Bi1–Bi2–C(ipso) angle in 3 (106.73(6)°]
the terphenyl substituents as reflected in the C(ipso)–Bi(1)– is similar to the corresponding angle (105.44(6)°] in uncom-
Bi(2)–C(ipso) torsion angles of 161.68 and 165.11° respec- plexed 2, the angle in 4 (102.37(7)°] is ca. 10° wider than
tively.[5] In contrast, related diphosphene complexes gen- that in Ar#Bi=BiAr#.
erally have the RP=PR unit bound in an end-on fashion to
The composition of 3 and 4 was confirmed by spectro-
the metal carbonyl fragment in related diphosphene com- scopic methods. Three bands were detected in the charac-
plexes.[4–7]
teristic region for the CO stretching vibration in the IR
1
Although the Bi–Bi bonds of 2.9432(2) and 2.9294(2) Å spectrum. In the H and 13C NMR spectra in C6D6 four
in 3 and 4 are significantly longer than the 2.8560(3) Å inequivalent environments were observed for the ortho-Me
observed in the free ligand ArЈBi=BiArЈ (2, vide infra) and iPr groups respectively, suggesting hindered rotation
and the related dibismuthenes ArBi=BiAr (Ar
=
about the Bi–C(ipso) bonds as well as the C–C bonds con-
2,4,6-{CH(SiMe3)2}3-C6H2, 2.8206(8) Å; Ar
=
Ar#, necting the aryl rings of the terphenyl ligands.[32] The obser-
2.833(2) Å],[10,11] the values are nonetheless shorter than vation of only one signal for the carbonyl groups in the
single bond lengths typically observed for Bi–Bi single 13C NMR spectrum may indicate fluxional behavior of the
bonds.[1] In addition, they are notably shorter than those in carbonyl ligands in solution.
the related complexes, [{W(CO)5}2{Bi2(CH2SiMe3)2}]
[Bi–Bi
3.0024(7) Å],[13a]
[{W(CO)5}2Bi2{CH2tBu}2]
[Bi–Bi 2.9979(7) Å][13b] and [Cp2Zr(Bi2Ar#2)] [Bi–Bi
3.1442(7) Å],[14] although they are longer than that
in the complex [{W(CO)5)(Bi2{CH2SiMe3}2)] (Bi–Bi
Conclusions
Reactions of ArBiCl2 (Ar = Ar#, ArЈ) with KSi-
2.8769(5) Å].[13a] This is consistent with theoretical investi- (SiMe3)3, K2Si2(SiMe3)4 and Na2[Fe(CO)4] have been
gations which have shown that some double bond character studied as possible routes to novel silicon and iron com-
of the Bi–Bi bond is preserved in the latter compound, al- pounds containing BiAr units. In all cases, the formation of
though not in the zirconocene complex which features a Bi–Bi bonded products was observed instead of simple salt
much longer Bi–Bi bond length.[14] In view of the signifi- metathesis due to a combination of the reducing power of
cantly larger inter-ligand repulsions in 3 and 4 compared to the anionic silicon and iron reagents, and the stability of
[W(CO)5{Bi2(CH2SiMe3)2}2], it seems likely that the Bi–Bi the Bi–Bi bonds. The dibismuthane ArЈ(Cl)BiBi(Cl)ArЈ (1)
bonds in 3 and 4 also retain some π-character.
was isolated from the reaction of ArЈBiCl2 with KSi-
The Bi–Fe bond lengths in 3 and 4 range from 2.8033(4) (SiMe3)3 while the reaction of ArЈBiCl2 with K2Si2-
to 2.8248(5) Å. These values are similar to those in the com- (SiMe3)4 yielded the corresponding dibismuthene ArЈBi=
plexes [{Fe(CO)4}2(BiPh2)2] and [Fe(CO)4(BiPh)]2 [2.823(2) BiArЈ (2). Interestingly, the related distibane Ar*(Cl)-
and 2.779(2) Å, respectively],[28] although they are at the SbSb(Cl)Ar*[11] could only be obtained as a mixture with
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Reactions of Terphenylbismuth Dihalides
CCD system (for 3 and 4). Absorption corrections were performed
using SADABS.[35,36] The structures were solved with direct meth-
ods and the non-hydrogen atoms were refined anisotropically (ex-
cept for disordered parts of the molecules, full-matrix least-squares
on F2).[38,39] The structure of 3 contained one toluene molecule in
the unit cell which was disordered over an inversion center and
refined as a rigid group using the AFIX instruction. The structure
of 4 also displayed a disordered toluene molecule. The affected car-
bon and hydrogen atoms were refined over split positions with iso-
tropic atomic displacement parameters. DFIX instructions were
Ar*Sb=SbAr* [Ar* = 2,6-(2,4,6-iPr3-C6H2)2-C6H3] from
the reduction of Ar*SbCl2 with KC8. Dipnictanes such as
Ar(Cl)E–E(Cl)Ar, may thus be viewed as likely intermedi-
ates in the formation of dipnictenes ArE=EAr (E = P, As,
Sb, and Bi).
The reaction of ArBiCl2 (Ar
=
Ar#, ArЈ) with
Na2[Fe(CO)4] afforded the iron-capped dibismuthene com-
plexes [Fe(CO)4(Bi2ArЈ2)] (3) and [Fe(CO)4(Bi2Ar#2)] (4) in
which the Fe(CO)4 moiety is coordinated to the Bi–Bi array
in a symmetrical face-on (η2) fashion. This coordination used to restrain the C–C distance in the disordered of methyl group
of the toluene molecule and EADP to constrain their thermal dis-
placement parameters. Further crystallographic details are given in
Table 2.
mode is generally observed for dibismuthenes RBi=BiR
while, in contrast, related diphosphenes exhibit more varied
coordination behavior in the presence of transition met-
als.[5–7]
CCDC-675732 (for 1), -675733 (for 2), -675734 (for 3), and -675735
(for 4) contain the supplementary crystallographic data for
this paper. These data can be obtained free of charge from The
Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif.
Experimental Section
General Methods: All manipulations were carried out with the use
of modified Schlenk techniques under an argon atmosphere or in
a Vacuum Atmospheres HE-43 drybox. All solvents were dried by
ArЈBiCl2: A solution of 6.07 g (15.0 mmol) of ArЈLi dissolved in
25 mL of toluene was added dropwise with stirring to a cold
(–80 °C) slurry of 5.68 g (18.0 mmol) of BiCl3 in 25 mL of toluene.
After the addition was complete, the reaction mixture was kept at
this temperature for an additional 2 h. The reaction was sub-
sequently warmed to room temperature and stirring was continued
for further 12 h. The reaction mixture was filtered through a filter-
tipped cannula, concentrated in vacuo to a volume of 10 mL and
storage at –20 °C for 48 h yielded ArЈBiCl2 as pale brown, almost
colorless crystals. Yield 5.03 g (49%); m.p. 148 °C. 1H NMR (C6D6,
the method of Grubbs[33] and degassed three times (freeze–pump–
thaw) prior to use. Ar#BiCl2,[11] KSi(SiMe3)3
and K2{Si2-
[19]
(SiMe3)4}[20] were prepared according to literature procedures.
1H NMR spectra were recorded on Varian 300 and 600 MHz in-
struments and referenced to the residual protio benzene in the
C6D6 or to the Me signal of the toluene solvent.
Data Collection and Structural Refinement of 1–4: Crystals of suf-
ficient quality for X-ray crystallography were removed from a
Schlenk tube under a stream of nitrogen and immediately covered
with a thin layer of hydrocarbon oil.[34] A suitable crystal was se-
lected, attached to a glass fiber, and quickly placed under a low-
temperature nitrogen stream. Data were recorded by using either a
Bruker SMART 1000 CCD (for 1 and 2) and a Bruker APEXII
3
+25 °C, 300.08 MHz): δ = 0.95 (d, JH–H = 6.6 Hz, 12 H, CH3),
3
3
1.26 (d, JH–H = 6.6 Hz, 12 H, CH3), 2.88 (sept, JH–H = 6.6 Hz, 4
3
3
H, CH), 7.10 (d, JH–H = 5.1 Hz, 2 H, m-H), 7.20 (t, JH–H
=
3
4.5 Hz, 2 H, p-H), 7.67 (d, JH–H = 4.5 Hz, 4 H, m-H) ppm.
13C{1H} NMR (C6D6, +25 °C, 75.45 MHz): δ = 23.2, 25.9, 30.9,
122.7, 123.4, 127.9, 130.0, 136.5, 148.1, 148.4, 182.1 ppm.
Table 2. Crystallographic data for 1–4.
1
2
3
4
Formula
M
T [K]
C60H74Bi2Cl2
1284.05
90(2)
C60H74Bi2Cl2
1213.15
90(2)
C52H50Bi2O4Fe·0.5C7H8 C64H74Bi2O4Fe·1.5C7H8
1258.80
90(2)
1519.24
90(2)
Crystal system
Space group
monoclinic
P21/n
orthorhombic
Pccn
triclinic
P1
monoclinic
C2/c
¯
a [Å]
b [Å]
c [Å]
α [°]
13.3721(6)
14.4248(6)
14.0513(6)
90
95.0270(10)
90
20.612(2)
15.757(2)
16.175(2)
90
90
90
11.3868(8)
11.5796(8)
19.395(2)
102.610(1)
92.643(1)
106.044(1)
2382.9(3)
2
46.289(2)
13.8362(5)
21.2717(8)
90
105.985(1)
90
β [°]
γ [°]
V [Å3]
2699.9(2)
2
5253.5(7)
4
13097.1(8)
8
Z
Crystal size [cm]
ρcalcd [Mgm–3]
F(000)
0.30ϫ0.10ϫ0.05
1.579
1268
6.644
–18/18, –20/20, 19/19
60.04
0.50ϫ0.48ϫ0.13
1.534
2400
6.726
–28/29, –22/22, 22/22
60.00
0.40ϫ0.10ϫ0.04
1.754
1222
7.712
–17/17, –17/17, 29/29
66.28
0.15ϫ0.10ϫ0.05
1.541
6056
5.628
–60/60, –17/17, 27/27
55.00
µ(Mo-Kα) [cm–1]
hkl range
2θmax [°]
Reflections collected/unique
R(int)
14150/7875
0.0386
7875/0/297
1.111
0.0393/0.1028
0.0566/0.1137
57741/7664
0.0501
7664/0/288
1.052
0.0254/0.0573
0.0332/0.0601
2.515/–1.477
41717/17308
0.0326
17308/0/551
1.071
0.0284/0.0739
0.0366/0.0779
2.763/–2.875
71067/15007
0.0374
15007/2/723
1.025
0.0211/0.0475
0.0273/0.0490
1.175/–0.999
Data/restraints/parameters
Goodness of fit on F2
R1/wR2 [IϾ2σ(I)]
R1/wR2 (all data)
Largest diff. peak/hole [eÅ–3] 3.521/–1.168
Eur. J. Inorg. Chem. 2008, 2515–2521
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
2519

R. Wolf, J. Fischer, R. C. Fischer, J. C. Fettinger, P. P. Power
ArЈ2Bi2Cl2 (1): To a cooled (0 °C) solution of 0.75 g (1.11 mmol) 142.99 (s, ArЈ), 145.22 (s, ArЈ), 145.33 (s, ArЈ), 146.97 (s, ArЈ),
FULL PAPER
of ArЈBiCl2 in 10 mL of toluene, was added dropwise a solution of
0.320 g (1.11 mmol) KSi(SiMe3)3 in 10 mL of toluene. This resulted
in an immediate color change from colorless to deep purple. After
concentration to about 5 mL and storage at room temperature for
48 h, 1 was obtained as colorless needles of suitable quality for X-
147.20 (s, ArЈ), 147.40 (s, ArЈ), 148.51 (s, ArЈ), 151.22 (s, ArЈ),
154.35 (s, ArЈ), 210.50 (s, Fe(CO) ) ppm. IR (Nujol ): ν = 2046 (s),
˜
4
1991 (w), 1977 (vs) cm–1. UV/Vis (hexanes): λmax (ε/Lmol–1 cm–1)
= 524 nm (740).
[Fe(CO)4(Bi2Ar#2)] (4): This compound was prepared by an analo-
ray crystallography. Yield 0.280 g (40%); m.p. Ͼ129 °C (decomp.).
gous procedure to
Na2[Fe(CO)4] (0.32 g,
3
using Ar#BiCl2 (0.9 g, 1.5 mmol) and
3
1H NMR (C6D6, +25 °C, 300.08 MHz): δ = 1.02 (d, JH–H
=
1.5 mmol).
C52H50Bi2FeO4·0.5C7H8
3
6.8 Hz, 12 H, CH3), 1.31 (d, JH–H = 6.8 Hz, 12 H, CH3), 2.88
(sept, JH–H = 6.8 Hz, 4 H, CH), 7.03 (d, JH–H = 3.6 Hz, 4 H, m-
(1212.22). Yield 0.14 g (15%) of a red-brown, crystalline solid.
Deep-red crystals of 4 were obtained by recrystallization of the
compound from toluene and storage of the saturated solution at
–7 °C for several days; m.p. 215 °C (decomp.). 1H NMR (C6D6,
+25 °C, 300.08 MHz): δ = 1.84 (s, 6 H, o-CH3 of Ar#), 2.04 (s, 6
H, o-CH3 of Ar#), 2.07 (s, 6 H, o-CH3 of Ar#), 2.11 (s, 5 H, 1 CH3
of C7H8), 2.17 (s, 6 H, o-CH3 of Ar#), 2.37 (s, 6 H, p-CH3 of
Ar#), 2.43 (s, 6 H, p-CH3 of Ar#), 6.80–7.00 (overlapping m, 16 H,
aromatic CH). 13C{1H} NMR (C6D6, +25 °C, 75.45 MHz): δ =
21.04 (s, CH3 of C7H8), 21.92 (s, o-CH3 of Ar#), 21.29 (s, o-CH3
of Ar#), 21.32 (s, o-CH3 of Ar#), 21.48 (s, o-CH3 of Ar#), 23.14 (s,
p-CH3 of Ar#), 23.50 (s, o-CH3 of Ar#), 125.74 (s, C7H8), 127.22
(s, Ar#), 127.93 (s, C7H8), 128.59 (s, C7H8), 128.83 (s, Ar#), 129.36
(s, Ar#), 129.44 (s, Ar#), 130.12 (s, Ar#), 135.77 (s, Ar#), 136.15 (s,
Ar#), 136.31 (s, Ar#), 136.74 (s, Ar#), 137.25 (s, Ar#), 137.53 (s,
C7H8), 143.36 (s, Ar#), 145.67 (s, Ar#), 151.50 (s, Ar#), 152.09 (s,
3
3
3
3
H), 7.06 (t, JH–H = 4.2 Hz, 2 H, p-H), 7.20 (t, JH–H = 4.2 Hz, 2
H, p-H), 7.68 (d, JH–H = 3.6 Hz, 4 H, m-H) ppm. 13C NMR
3
(C6D6, +25 °C, 75.45 MHz): δ = 23.2, 25.9, 31.1, 122.8, 123.4,
128.5, 130.0, 136.6, 147.7, 148.3 ppm; C (ipso) of the ArЈ ligand not
observed. UV/Vis (hexanes): λmax (ε/Lmol–1 cm–1) = 325 (shoulder),
542 nm (3100).
ArЈ2Bi2 (2): To a solution of 0.67 g (0.95 mmol) of ArЈBiCl2 in
15 mL of toluene, precooled to –80 °C, was added a solution of
0.943 g (1.00 mmol) of 1,2-dipotassio-1,1,2,2-tetrakis(trimethylsi-
lyl)disilane dissolved in 20 mL of toluene. The reaction micture and
was kept at this temperature for 2 h whereupon the reaction mix-
ture adopted a purple color that intensified upon subsequent
warming to room temperature. Stirring was continued for 12 h and
the dark purple solution was then concentrated in vacuo to ca.
15 mL and filtered using a filter tipped cannula. The volume of the
filtrate was reduced to ca. 7 mL and storage at ca. –20 °C yielded
dark purple, almost black crystals of 2 of suitable quality for X-
ray crystallography. Yield 0.390 g (72%); m.p. 156–158 °C. UV/Vis
(hexanes): λmax (ε/Lmol–1 cm–1) = 308 (shoulder), 356 (shoulder),
526 nm (2900). 1H NMR (C6D6, +25 °C, 300.08 MHz): δ = 0.99
Ar#), 206.58 (s, Fe(CO) ) ppm. IR (Nujol): ν = 2044 (s), 1989 (m),
˜
4
1983 (s), 1966 (s) cm–1. UV/Vis (thf): λmax (ε/Lmol–1 cm–1) =
572 nm (580).
Acknowledgments
3
(d, J = 6.6 Hz, 12 H, CH3), 1.16 (d, JH–H = 6.6 Hz, 12 H, CH3),
3
3
2.72 (sept, JH–H = 6.6 Hz, 4 H, CH), 7.04 (d, JH–H = 7.8 Hz, 4
Financial support from the Alexander von Humboldt Foundation
(Lynen fellowship to R. W.), the Austrian Fonds zur Förderung der
wissenschaftlichen Forschung (Schrödinger fellowship to J. F.) and
the Max Kade Foundation (fellowship to R. C. F.) and the U. S.
National Science Foundation is gratefully acknowledged.
3
3
H, m-H), 7.08 (t, JH–H = 7.2 Hz, 2 H, m-H), 7.11 (t, JH–H
=
3
7.2 Hz, 2 H, p-H), 7.23 (d, JH–H = 7.8 Hz, 4 H, m-H) ppm.
13C{1H} NMR (C6D6, +25 °C, 75.45 MHz): δ = 24.30, 26.37,
31.05, 122.70, 123.69, 129.36, 140.91, 145.0, 146.69, 147.23, 154.32
ppm.
[Fe(CO)4(Bi2ArЈ2)] (3): A solution of ArЈBiCl2 (1.0 g, 1.5 mmol) in
ca. 30 mL of THF was added to a suspension of Na2[Fe(CO)4]
(0.32 g, 1.5 mmol) in ca. 15 mL of THF at –78 °C. An orange sus-
pension formed immediately and the mixture was warmed to room
temperature over several hours, then stirred overnight. The solvent
was removed, the dark residue was extracted with toluene (60 mL)
and the mixture was filtered. The deep-red filtrate was concentrated
to ca. 8 mL and storage of this solution at ambient temperature for
two days gave deep-red crystals of 3 which were isolated. After
drying in the vacuum for ca. 1 h the compound still contains one
equiv. of toluene per molecule of 3. Yield 0.28 g (25%); m.p. 246–
248 °C. 1H NMR (C6D6, +25 °C, 300.08 MHz): δ = 0.94–1.11
(overlapping m, 30 H, CH3), 1.27 (d, CH3, J = 6.9 Hz, 6 H, CH3),
1.39 (d, J = 6.9 Hz, 6 H, CH3), 1.62 (d, J = 6.9 Hz, 6 H, CH3),
2.11 (s, 3 H, CH3 of C7H8), 2.53 (sept, J = 6.9 Hz, 2 H, CH), 2.83
(sept, J = 6.9 Hz, 2 H, CH), 2.94 (sept, J = 6.9 Hz, 2 H, CH), 3.42
(sept, J = 6.9 Hz, 2 H, CH), 6.97–7.35 (overlapping m, 22 H, aro-
matic CH) ppm. 13C{1H} NMR (C6D6, +25 °C, 75.45 MHz): δ =
21.43 (s, CH3 of C7H8), 23.22 (s, CH3 of iPr), 24.14 (s, CH3 of iPr),
25.42 (s, CH3 of iPr), 25.63 (s, CH3 of iPr), 26.02 (s, CH3 of iPr),
26.13 (s, CH3 of iPr), 27.24 (s, CH3 of iPr), 28.06 (s, CH3 of iPr),
29.96 (s, CH of iPr), 30.15 (s, CH of iPr), 31.09 (s, CH of iPr),
33.37 (s, CH of iPr), 122.85 (s, ArЈ), 124.23 (s, ArЈ), 124.63 (s, ArЈ),
125.29 (s, ArЈ), 125.72 (s, C7H8), 126.77 (s, ArЈ), 127.76 (s, ArЈ),
127.94 (s, C7H8), 128.60 (s, C7H8), 128.81 (s, ArЈ), 129.31 (s, ArЈ),
129.36 (s, ArЈ), 129.58 (s, ArЈ), 129.91 (s, ArЈ), 137.92 (s, C7H8),
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www.eurjic.org
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Received: December 12, 2007
Published Online: March 10, 2008
Eur. J. Inorg. Chem. 2008, 2515–2521
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
2521