Organobismuth(III) dihalides with T-shaped geometry stabilized by intramolecular N→Bi interactions and related diorganobismuth(III) halides

Article abstract of DOI:10.1021/om0611608

Organobismuth(III) compounds containing (N,C,N)-pincer ligands were prepared and characterized both in solution and in the solid state. Compound RBiCl₂ 1 [R = 2,6-(Me₂NCH₂)₂C ₆H₃] was obtained from RLi and BiCl₃ (1:1 molar ratio). RBiBr₂ 2 and RBiI₂ 3 were obtained by halogen-exchange reactions from 1. Reaction of 1 with MeMgI afforded RBi(Me)I 4. Compound R₂BiCl 5, obtained from RLi and BiCl₃, is rearranged in solution to 1 and R₃Bi. The molecular structures of compounds 1-5 were established by single-crystal X-ray diffraction. All dihalides RBiX₂ show a T-shaped CBiX₂ core. They are the first stable compounds corresponding to the edge inversion transition state at the bismuth center, stabilized by two strong intramolecular N→Bi interactions in trans positions to each other, which contribute to an overall distorted square pyramidal (N,C,N)BiX₂ coordination geometry. The electronic structure of [2,6(Me₂NCH₂) ₂C₆H₃]BiCl₂ (1) was analyzed by density functional theory (DFT) calculations, which provide evidence that the stabilization of the square pyramidal geometry of bismuth is electronic rather than steric in nature.

Full text of DOI:10.1021/om0611608

1196
Organometallics 2007, 26, 1196-1203
Organobismuth(III) Dihalides with T-Shaped Geometry Stabilized
by Intramolecular NfBi Interactions and Related
Diorganobismuth(III) Halides
Albert P. Soran,† Cristian Silvestru,*,† Hans J. Breunig,‡ Gabor Bala´zs,§ and
Jennifer C. Green§
Facultatea de Chimie s¸i Inginerie Chimicaˇ, UniVersitatea “Babes¸-Bolyai”, 400028-Cluj-Napoca, Romania,
Institut fu¨r Anorganische und Physikalische Chemie, UniVersita¨t Bremen, 28334-Bremen, Germany, and
Inorganic Chemistry Laboratory, UniVersity of Oxford, OX1 3QR Oxford, United Kingdom
ReceiVed December 20, 2006
Organobismuth(III) compounds containing (N,C,N)-pincer ligands were prepared and characterized
both in solution and in the solid state. Compound RBiCl2 1 [R ) 2,6-(Me2NCH2)2C6H3] was obtained
from RLi and BiCl3 (1:1 molar ratio). RBiBr2 2 and RBiI2 3 were obtained by halogen-exchange reactions
from 1. Reaction of 1 with MeMgI afforded RBi(Me)I 4. Compound R2BiCl 5, obtained from RLi and
BiCl3, is rearranged in solution to 1 and R3Bi. The molecular structures of compounds 1-5 were established
by single-crystal X-ray diffraction. All dihalides RBiX2 show a T-shaped CBiX2 core. They are the first
stable compounds corresponding to the edge inversion “transition state” at the bismuth center, stabilized
by two strong intramolecular NfBi interactions in trans positions to each other, which contribute to an
overall distorted square pyramidal (N,C,N)BiX2 coordination geometry. The electronic structure of [2,6-
(Me2NCH2)2C6H3]BiCl2 (1) was analyzed by density functional theory (DFT) calculations, which provide
evidence that the stabilization of the square pyramidal geometry of bismuth is electronic rather than
steric in nature.
C6H4; R′ ) Me, CF3], were also described.8 By contrast, few
organobismuth(III) compounds containing a 2,6-bis(dimethyl-
Introduction
aminomethyl)phenyl group, i.e., RBiCl2 19 and RBi[C6H4-
{C(CF3)2O}-2] [R ) 2,6-(Me2NCH2)2-4-R′C6H2, R′ ) H, tBu],4
were reported until 1998. In all these compounds intramolecular
NfBi interactions were observed both in the solid state and in
solution. Our recent work has been concerned with organobis-
muth compounds containing 2-(Me2NCH2)C6H4 and 2,6-(Me2-
NCH2)2C6H3 groups,10 since these ligands are able to coordinate
not only through the carbon atom but also through the pendent
amino groups to the metal atom and thus provide well-protected
hypervalent organobismuth compounds.11 Indeed, we were able
to isolate and to characterize low-valent organobismuth species
such as cyclo-[2-(Me2NCH2)C6H4]4Bi4,10a R4Bi2 [R ) 2-(Me2-
NCH2)C6H4,10a 2,6-(Me2NCH2)2C6H310e], the first functionalized
organobismuth(III) derivatives of the type [2-(Me2NCH2)C6H4]-
Interest in the chemistry of organobismuth(III) compounds
has increased in recent years,1 due to the potential biological
activity and use, for example, as reagents and catalysts in organic
synthesis (e.g., phenylation agent or mild oxidizing agents) and
as precursors in advanced material science and heterometallic
cluster chemistry (including compounds with bismuth-transition
metal and bismuth-bismuth bonds). A recent review of the
structural chemistry of organobismuth compounds2 revealed that
until 1998 relatively little attention was devoted to organobis-
muth compounds containing aryl groups ortho-substituted with
CH2NMe2 or related pendent arms. Known examples of orga-
nobismuth(III) derivatives containing 2-(dimethylaminomethyl)-
phenyl or related aryl groups with one pendent arm are
RBi[C6H4{C(CF3)2O}-2],3,4 RR′BiCl (R′ ) 4-MeOC6H4, 4-
MeC6H4, Ph, 4-ClC6H4, 1-naphthyl),5 RPhBiBr,5 [2-{Me2N-
(Me)CH}C6H4]R′BiCl (R′ ) Ph, 1-naphthyl),5,6 R3Bi,7a R2-
BiCl,7b RBiX2 (X ) Cl, I),7b and [R2Bi]+[PF6]- 7c [R ) 2-(Me2-
NCH2)C6H4]. A few examples of organobismuth(V) compounds,
i.e., R(4-R′C6H4)2Bi[C6H4{C(CF3)2O}-2] [R ) 2-(Me2NCH2)-
(7) a) Kamepalli, S.; Carmalt, C. J.; Culp, R. D.; Cowley, A. H.; Jones,
R. A.; Norman, N. C. Inorg. Chem. 1996, 35, 6179. (b) Carmalt, C. J.;
Cowley, A. H.; Culp, R. D.; Jones, R. A.; Kamepalli, S.; Norman, N. C.
Inorg. Chem. 1997, 36, 2770. (c) Carmalt, C. J.; Walsh, D.; Cowley, A.
H.; Norman, N. C. Organometallics 1997, 16, 3597. (d) James, S. C.;
Norman, N. C.; Orpen, A. G. J. Chem. Soc., Dalton Trans. 1999, 2837.
(8) Yamamoto, Y.; Ohdoi, K.; Chen, X.; Kitano, M.; Akiba, K.
Organometallics 1993, 12, 3297.
* To whom correspondence should be addressed. E-mail: cristi@
chem.ubbcluj.ro.
† Universitatea “Babes¸-Bolyai” Cluj Napoca.
‡ Universita¨t Bremen.
(9) Atwood, D. A.; Cowley, A. H.; Ruiz, J. Inorg. Chim. Acta 1992,
198-200, 271.
§ University of Oxford.
(10) (a) Bala´zs, L.; Breunig, H. J.; Lork, E.; Silvestru, C. Eur. J. Inorg.
Chem. 2003, 1361. (b) Bala´zs, L.; Staˆngaˇ, O.; Breunig, H. J.; Silvestru, C.
Dalton Trans. 2003, 2237. (c) Breunig, H. J.; Ghes¸ner, I.; Ghes¸ner, M. E.;
Lork, E. Inorg. Chem. 2003, 42, 1751. (d) Breunig, H. J.; Bala´zs, L.; Philipp,
N.; Soran, A.; Silvestru, C. Phosphorus, Sulfur Silicon 2004, 179, 853. (e)
Bala´zs, L.; Breunig, H. J.; Lork, E.; Soran, A.; Silvestru, C. Inorg. Chem.
2006, 45, 2341. (f) Ferna´ndez, E. J.; Laguna, A.; Lo´pez-de-Luzuriaga, J.
M.; Monge, M.; Nema, M.; Olmos, M. E.; Pe´rez, J.; Silvestru, C. Chem.
Commun. 2006, DOI: 10.1039/b613365g.
(1) Suzuki, H., Matano, Y., Eds. Organobismuth Chemistry; Elsevier
Science B. V.: Amsterdam, 2001.
(2) Silvestru, C.; Breunig, H. J.; Althaus, H. Chem. ReV. 1999, 99, 3277.
(3) Yamamoto, Y.; Chen, X.; Akiba, K. J. Am. Chem. Soc. 1992, 114,
7906.
(4) Yamamoto, Y.; Chen, X.; Kojima, S.; Ohdoi, K.; Kitano, M.; Doi,
Y.; Akiba, K. J. Am. Chem. Soc. 1995, 117, 3922.
(5) Suzuki, H.; Murafuji, T.; Matano, Y.; Azuma, N. J. Chem. Soc.,
Perkin Trans. 1 1993, 2969.
(11) Akiba, K., Ed. Chemistry of HyperValent Compounds; Wiley-
VCH: New York, 1999.
(6) Murafuji, T.; Azuma, N.; Suzuki, H. Organometallics 1995, 14, 1542.
10.1021/om0611608 CCC: $37.00 © 2007 American Chemical Society
Publication on Web 01/30/2007

Organobismuth(III) Dihalides
Scheme 1
Organometallics, Vol. 26, No. 5, 2007 1197
the diiodide 3 in almost quantitative yields. The analogous
difluoride could not be isolated using a similar method even if
a large excess of potassium or ammonium fluoride was used.
Similar behavior has also been mentioned in the literature.1,13
1
The H NMR spectrum of 1 in CDCl3 or CD2Cl2 at room
temperature shows singlet signals for both the methylene and
methyl protons and the corresponding doublet and triplet signals
for the aromatic protons. This suggests equivalence of aliphatic
protons from the two pendent arms. Low-temperature NMR
spectra in CD2Cl2, down to -55 °C, showed no modification
in the pattern of the resonance signals, thus indicating a high
symmetry on the NMR time scale. The NMR spectra of the
related dihalides 2 and 3 exhibit a similar pattern. A comparison
of the 13C NMR spectra of compounds 1-3 revealed a notable
high-field shift of the resonance signal corresponding to the
carbon atom (C-1) directly attached to bismuth when chlorine
is exchanged with bromine or iodine, respectively.
BiCl[(XPR2)(YPR′2)N] (X, Y ) O, S, Se; R, R′ ) Me, Ph),10b
and organobismuth heterocycles (RBiS)2 [R ) 2-(Me2NCH2)-
C6H4, 2,6-(Me2NCH2)2C6H3].10d We have also reported the
unusual reaction of the dibismuthane R2Bi-BiR2 with oxygen
leading to the formation of the first peroxo derivative [{2,6-
(Me2NCH2)2C6H3}2Bi]2(O2)10e and [2-(Me2NCH2)C6H4]2BiAu-
(C6F5)2, a compound that exhibits the first metallophilic AuI‚‚
‚BiIII closed-shell interaction.10f
Crystal Structures of [2,6-(Me2NCH2)2C6H3]BiX2 (1-3).
Crystal structures of the dihalides 1-3 were determined by
X-ray diffraction from single crystals obtained by slow diffusion
of n-hexane into a solution of the compound 1 in methylene
chloride or by allowing hot, saturated DMSO solutions of
compounds 2 and 3 to slowly reach room temperature. The
solid-state molecular structures of all three compounds are very
similar, as reflected by the selected molecular parameters given
in Table 1. They exhibit a similar striking feature, i.e., a
T-shaped geometry of the CBiX2 core, with trans halogen atoms
(Cl(1)-Bi(1)-Cl(2) 173.73(3)°, Br(1)-Bi(1)-Br(1a) 175.87-
(3)°, and I(1)-Bi(1)-I(1a) 179.70(2)°) (see Figure 1 for the
dichloride 1).
In earlier reports, on the basis of multinuclear NMR solution
studies of RBi[C6H4{C(CF3)2O}-2] [R ) 2-(Me2NCH2)C6H4;
t
2,6-(Me2NCH2)2-4-R′C6H2, R′ ) H, Bu],3,4 Yamamoto et al.
concluded that external (solvent molecules) or internal (in-
tramolecularly coordinating groups) nucleophiles can consider-
ably reduce the barrier for the edge inversion of bismuth(III)
compounds through a “transition state” with a T-shaped (C,O)-
CBi core. It should be noted here that the structure of the related
organoantimony(III) derivative, [2,6-(Me2NCH2)2C6H3]SbCl2,
indeed exhibits a T-shaped CSbCl2 core, in this case the
stabilization induced by the two internal coordinated nitrogen
atoms from the pendent arms being so strong that an edge
inversion “transition state” had become a ground state.7a
Herein we report the synthesis, spectroscopic characterization,
and crystal structures of the dihalides [2,6-(Me2NCH2)2C6H3]-
BiX2 (X ) Cl, Br, I), which are the first compounds with a
T-shaped CBiX2 core stabilized by two intramolecular NfBi
interactions. Some T-shaped organobismuth(III) halides with
two intermolecular NfBi interactions were already described.7d
Related compounds with a T-shaped CBiX2 core stabilized by
two intramolecular OfBi interactions were recently described.12
The stabilization of the overall square pyramidal geometry of
bismuth is of electronic rather than steric origin, as indicated
by the DFT calculations carried out on the dichloro derivative.
The synthesis and structure of two related diorganobismuth-
(III) halides, [2,6-(Me2NCH2)2C6H3]2BiCl and [2,6-(Me2-
NCH2)2C6H3](Me)BiI, are also discussed.
Both nitrogen atoms of the organic ligand are strongly
coordinated to bismuth in an almost trans arrangement (N(1)-
Bi(1)-N(2) 144.2(1)° in 1; N(1)-Bi(1)-N(1a) 144.3(2)° and
143.7(2)° in 2 and 3, respectively). This deviation from the ideal
angle of 180° is due to the constraints imposed by the
coordinated amine arms. The overall geometry at the bismuth
center is distorted square pyramidal, with the carbon atom in
the apical position. The T-shape arrangement of the CBiX2 core
together with the nitrogen dative bonds resembles a transition
state in the edge inversion mechanism proposed by Dixon and
Arduengo,14 and compounds 1-3 can be described as hyper-
valent 12-Bi-5 species.15
The trans Bi-halogen bond lengths in compounds 1-3 are
considerably longer (Bi(1)-Cl 2.701(1) and 2.706(1) Å in 1;
Bi(1)-Br(1) 2.840(1) Å in 2; Bi(1)-I(1) 3.082(1) Å in 3) than
characteristic Bi-halogen covalent bonds (∑cov(Bi,X) 2.51, 2.66,
and 2.85 Å for X ) Cl, Br, and I, respectively),16 which is in
agreement with the 3c-4e theory of the hypervalent bond
formation. Similar values were found for the Bi-halogen
distances in the polymeric structures of MeBiCl2 (2.741, 2.755
Å),17 PhBiBr2 (2.880, 2.925 Å),18 and MeBiI2 (3.086-3.128
Results and Discussion
Synthesis and Spectroscopic Characterization of [2,6-
(Me2NCH2)2C6H3]BiX2 (1-3). The dichloride [2,6-(Me2-
NCH2)2C6H3]BiCl2 (1) was synthesized by a slightly modified
and improved procedure of that previously reported by Cowley
and co-workers (for details, see Supporting Information).9 In
order to investigate the influence of the nature of the halogen
on the coordination sphere of the bismuth center, several
experiments were carried out (Scheme 1). The halide exchange
reactions between 1 and an excess of the appropriate potassium
halide were performed in a two-layer solvent system (H2O/
EtOH/CH2Cl2) and resulted in isolation of the dibromide 2 and
(13) Shimada S.; Yamazaki O.; Tanaka T.; Suzuki, Y.; Tanaka, M. J.
Organomet. Chem. 2004, 689, 3012.
(14) Dixon, D. A.; Arduengo, A. J., III; Fukunaga, T. J. Am. Chem. Soc.
1986, 108, 2461. (b) Dixon, D. A.; Arduengo, A. J., III. J. Chem. Phys.
1987, 91, 3195.
(15) The N-X-L nomenclature system has been previously described: N
valence shell electrons about a central atom X with L ligands. Perkins, C.
W.; Martin, J. C.; Arduengo, A. J., III; Lau, W.; Alegria, A.; Kochi, K. J.
Am. Chem. Soc. 1980, 102, 7753.
(16) Emsley, J. Die Elemente; Walter de Gruyter: Berlin, 1994.
(17) Althaus, H.; Breunig, H. J.; Lork, E. Organometallics 2001, 20,
586.
(12) (a) Peveling, K. Ph.D. Thesis, Universita¨t Dortmund, Germany,
2003. (b) Dosta´l, L.; Cisarˇova´, I.; Jambor, R.; Ru˚zˇicˇka, A.; Jira´sko, R.;
Holecˇek, J. Organometallics 2006, 25, 4366.
(18) Clegg, W.; Elsegood, M. R. J.; Errington, R. J.; Fisher, G. A.;
Norman, N. C. J. Mater. Chem. 1994, 4, 891.

1198 Organometallics, Vol. 26, No. 5, 2007
Soran et al.
Table 1. Selected Bond Distances [Å] and Angles [deg] for Compounds 1-3
2a
1
3a
Bi(1)-C(1)
2.224(4)
2.7012(11)
2.7062(11)
2.561(3)
2.570(4)
1.482(5)
1.477(5)
1.471(5)
1.493(5)
1.476(6)
1.482(6)
173.73(3)
87.11(10)
86.62(10)
72.14(13)
72.04(14)
144.18(11)
94.57(8)
83.79(8)
83.87(9)
93.90(9)
109.8(3)
110.6(3)
110.0(4)
104.2(2)
113.5(3)
108.7(3)
110.1(4)
110.4(4)
110.9(4)
104.2(3)
108.7(3)
112.4(3)
Bi(1)-C(1)
Bi(1)-Br(1)
2.194(10)
2.8404(9)
Bi(1)-C(1)
Bi(1)-I(1)
2.216(7)
3.0819(6)
Bi(1)-Cl(1)
Bi(1)-Cl(2)
Bi(1)-N(1)
Bi(1)-N(1)
2.566(5)
Bi(1)-N(1)
2.589(4)
Bi(1)-N(2)
N(1)-C(7)
N(1)-C(5)
N(1)-C(6)
N(1)-C(7)
1.459(9)
1.460(8)
1.461(9)
N(1)-C(5)
N(1)-C(6)
N(1)-C(7)
1.484(7)
1.466(7)
1.481(6)
N(1)-C(8)
N(1)-C(9)
N(2)-C(10)
N(2)-C(11)
N(2)-C(12)
Cl(1)-Bi(1)-Cl(2)
C(1)-Bi(1)-Cl(1)
C(1)-Bi(1)-Cl(2)
C(1)-Bi(1)-N(1)
C(1)-Bi(1)-N(2)
N(1)-Bi(1)-N(2)
N(1)-Bi(1)-Cl(1)
N(1)-Bi(1)-Cl(2)
N(2)-Bi(1)-Cl(1)
N(2)-Bi(1)-Cl(2)
C(7)-N(1)-C(8)
C(7)-N(1)-C(9)
C(8)-N(1)-C(9)
Bi(1)-N(1)-C(7)
Bi(1)-N(1)-C(8)
Bi(1)-N(1)-C(9)
C(10)-N(2)-C(11)
C(10)-N(2)-C(12)
C(11)-N(2)-C(12)
Bi(1)-N(2)-C(10)
Bi(1)-N(2)-C(11)
Bi(1)-N(2)-C(12)
Br(1)-Bi(1)-Br(1a)
C(1)-Bi(1)-Br(1)
175.87(3)
87.93(2)
I(1)-Bi(1)-I(1a)
C(1)-Bi(1)-I(1)
179.70(2)
90.15(1)
C(1)-Bi(1)-N(1)
72.17(12)
C(1)-Bi(1)-N(1)
71.83(9)
N(1)-Bi(1)-N(1a)
N(1)-Bi(1)-Br(1)
N(1)-Bi(1)-Br(1a)
144.3(2)
95.53(11)
83.20(12)
N(1)-Bi(1)-N(1a)
N(1)-Bi(1)-I(1)
N(1)-Bi(1)-I(1a)
143.66(18)
95.52(9)
84.57(9)
C(5)-N(1)-C(6)
C(5)-N(1)-C(7)
C(6)-N(1)-C(7)
Bi(1)-N(1)-C(5)
Bi(1)-N(1)-C(6)
Bi(1)-N(1)-C(7)
110.1(5)
110.3(6)
109.1(6)
103.9(4)
115.1(4)
108.2(4)
C(5)-N(1)-C(6)
C(5)-N(1)-C(7)
C(6)-N(1)-C(7)
Bi(1)-N(1)-C(5)
Bi(1)-N(1)-C(6)
Bi(1)-N(1)-C(7)
110.1(5)
109.8(4)
109.2(5)
103.6(3)
108.8(3)
115.1(3)
a Symmetry equivalent atoms (1-x, y, 1.5-z) for 2 and (1-x, y, 0.5-z) for 3 are given by “a”.
for the 2,6-(Me2NCH2)2C6H3 ligand is well established in the
transition metal chemistry.20
As result of the intramolecular coordination of the nitrogen
to the bismuth atom, two five-membered BiC3N rings are
formed. These rings are folded along the Bi(1)‚‚‚Cmethylene axis,
with the nitrogen atom lying above the best plane defined by
the residual BiC3 system. This folding induces planar chirality
(with the aromatic ring and the nitrogen atoms as chiral plane
and pilot atoms, respectively)21 as described for other related
compounds,22 and indeed compounds 1-3 crystallize as race-
mates, i.e., 1:1 mixtures of (SN1,SN2) and (RN1,RN2) isomers (with
respect to the two chelate rings in a molecular unit). In the
crystal both halogen atoms of a molecular unit are involved in
Bi-X‚‚‚Bi bridges, thus resulting in the formation of a doubly
bridged polymeric chain that contains alternating (SN1,SN2) and
(RN1,RN2) isomers in an anti arrangement regarding the axis of
the polymer (see Figure 2 for the dibromide 2). The intermo-
lecular Bi‚‚‚X interactions are week. The corresponding contact
Figure 1. Molecular structure of the (SN1,SN2) isomer of 1 (ORTEP
drawing with 30% probability ellipsoids) with the labeling scheme
for the atom positions.
Å),19 built on the basis of angular, slightly asymmetric Bi-
X-Bi systems.
(20) (a) van Koten, G. Pure Appl. Chem. 1989, 61, 1681. (b) van Koten,
G. Pure Appl. Chem. 1990, 62, 1155. (c) van Koten, G.; Terheijden, J.;
van Beek, J. A. M.; Wehman-Ooyevaar, I. C. M.; Muller, F.; Stan, C. H.
Organometallics 1990, 9, 903. (d) van Koten, G.; Jastrzebski, J. T. B. H.;
Noh, J. G.; Spek, A. L.; Shoone, I. C. J. Organomet. Chem. 1978, 148,
233. (e) Yoshifuji, M.; Otoguro, A.; Toyota, K. Bull. Chem. Soc. Jpn. 1994,
67, 1503.
The Bi-N distances in compounds 1-3 are similar regardless
of the nature of the halogen [1, 2.561(3), 2.570(4) Å; 2, 2.566-
(5) Å; 3, 2.589(4) Å] and lie between the sums of the
corresponding covalent (∑cov(Bi,N) 2.22 Å) and van der Waals
radii (∑vdW(Bi,N) 3.94 Å).16 These internal Bi-N interactions
are much stronger than those observed in the related [2,6-(Me2-
NCH2)2C6H3]Bi[C6H4{C(CF3)2O}-2] derivative (2.68(1), 2.86-
(1) Å), which however exhibits a pyramidal arrangement of the
covalent bonds at bismuth.4 The (N,C,N)-coordination pattern
(21) IUPAC Nomenclature of Organic Chemistry; Pergamon Press:
Oxford, 1979.
(22) (a) Opris¸, L. M.; Silvestru, A.; Silvestru, C.; Breunig, H. J.; Lork,
E. Dalton Trans. 2003, 4367. (b) Bumbu, O.; Silvestru, C.; Gimeno, M.
C.; Laguna, A. J. Organomet. Chem. 2004, 689, 1172. (c) Opris¸, L. M.;
Silvestru, A.; Silvestru, C.; Breunig, H. J.; Lork, E. Dalton Trans. 2004,
3575. (d) Varga, R. A.; Silvestru, C.; Deleanu, C. Appl. Organomet. Chem.
2005, 19, 153. (e) Kulcsar, M.; Silvestru, A.; Silvestru, C.; Drake, J. E.;
Macdonald, C. L. B.; Hursthouse, M. E.; Light, M. E. J. Organomet. Chem.
2005, 690, 3217. (f) Varga, R. A.; Rotar, A.; Schu¨rmann, M.; Jurkschat
K.; Silvestru, C. Eur. J. Inorg. Chem. 2006, 1475.
(19) Wang, S.; Mitzi, D. B.; Landrum, G. A.; Genin, H.; Hoffmann, R.
J. Am. Chem. Soc. 1997, 119, 724.

Organobismuth(III) Dihalides
Organometallics, Vol. 26, No. 5, 2007 1199
Figure 2. View along a-axis of the supramolecular association
based on intermolecular bismuth-bromine interactions in the crystal
of 2 [symmetry equivalent atoms (x, 1-y, -0.5+z) and (1-x, 1-y,
2-z) for Br1a′ and Br1′′, respectively]. Hydrogen atoms are omitted
for clarity.
Figure 4. Isosurfaces of selected molecular orbitals of 1. The
orbitals are labeled in the C2 symmetry.
out-of-phase combination of the Bi py and N py orbitals forms
the LUMO (26b), while the HOMO (28a) is formed by the lone
pairs of the chlorine atoms containing relatively small Bi
contribution (s and pz). The high stability of 1 is also confirmed
by the large HOMO-LUMO gap (3.62 eV).
The analysis of the Hirshfeld charge distributions shows that
1 is relatively strongly polarized. The chlorine atoms are clearly
negatively charged (-0.32), the nitrogen atoms are slightly
(-0.03) negatively charged, while the bismuth atom is positively
charged (0.49).
Considering the orbital interactions described above and the
charge distribution, overall the bonding in 1 is excellently
described by two three-center-four-electron bonds (Bi-Cl and
Bi-N) and a two-center-two-electron bond (Bi-C).
Figure 3. Optimized structure of [2,6-(Me2NCH2)2C6H3]BiCl2, 1.
Selected distances (Å) and angles (deg): Bi-Cl 2.67, Bi-N 2.54,
Bi-C 2.22; N-Bi-N 143.8, Cl-Bi-Cl 175.4.
To quantify the stabilization obtained by the coordination of
the pendent -CH2NMe2 arms to the Bi, the relative energies
of different isomers of 1 (Figure 5) were calculated. In the
structure of lowest energy both nitrogen atoms are coordinated
to bismuth (1), which was also observed experimentally in the
crystal structure. To evaluate the amount of stabilization of one
NfBi interaction, one pendent -CH2NMe2 arm was rotated
180° around the C-C(Ph) bond in such a way that the nitrogen
is situated far away from the bismuth atom and hence one NfBi
interaction is eliminated. Geometry optimization without any
constraints leads to a geometry with a bent Cl-Bi-Cl unit (1a),
which is 17.61 kcal‚mol-1 higher in energy than 1. Constraining
in 1a the Cl-Bi-Cl angle to linearity (1b) leads to only a slight
increase in energy (0.22 kcal‚mol-1) compared to 1a. The
elimination of the second NfBi interaction in 1a gives rise to
an increase in energy of 9.76 kcal‚mol-1 for 1c compared to
1a. If the Cl-Bi-Cl angle is enforced to linearity and both
bismuth-nitrogen interactions are cancelled (1d), then the
structure increases considerably in energy. Overall the two
NfBi coordinations of the two -CH2NMe2 pendent arms
distances [1, Bi(1)‚‚‚Cl(1′) 3.620(1) Å, Bi(1)‚‚‚Cl(2′′) 3.545(1)
Å; 2, Bi(1)‚‚‚Br(1′′) 3.818(1) Å; 2, Bi(1)‚‚‚I(1′) 4.021(1) Å]
are shorter than the sums of the corresponding van der Waals
radii (∑vdW(Bi,X) 4.21, 4.35, and 4.55 Å for X ) Cl, Br, and I,
respectively).16
DFT Calculations. The electronic structure of 1 was analyzed
by density functional theory (DFT) calculations to gain insight
into the nature of bonding and to clarify why in this type of
complexes a square pyramidal geometry is favored over a
trigonal pyramidal geometry. The structure of 1 was optimized
at the DFT level of theory without symmetry restraints, but the
optimized structure was very close to C2 symmetry (Figure 3).
Hence the orbitals are labeled either a or b corresponding to
the irreducible representations of this point group. The calculated
Bi-Cl (2.67 Å) and Bi-N (2.54 Å) distances are in good
agreement with the corresponding experimental distances
determined by single-crystal X-ray diffractions (Bi-Cl 2.7012-
(11) and 2.7062(11) Å; Bi-N 2.561(3) and 2.570(4) Å). Also
the other calculated geometrical parameters are in good agree-
ment with the experimental data.
The bonding in 1 was analyzed by considering the interaction
of the bismuth atomic orbitals with those of the ligands. This
shows no hybridization of the Bi s and p orbitals. For the
bonding, the bismuth atom uses only its 6p orbitals, while the
6s orbital remains nonbonding. The Bi-Cl bonding is realized
through in-phase combination of the Bi px orbital with the px
orbitals of both chlorine atoms, leading to a bonding molecular
orbital (MO) (21b in Figure 4). Similarly the Bi py orbital mixes
mainly with the py orbitals of the two nitrogen atoms of the
-CH2NMe2 pendent arms to give a Bi-N bonding MO (22b).
The Bi-C bonding is realized mainly through the Bi pz orbital
and the ipso carbon pz orbital of the aromatic ring (23a). The
stabilize the square pyramidal geometry by 38.40 kcal‚mol-1
.
The analysis of the calculated relative energies of different
isomers of 1 shows that only one NfBi coordination is not
enough to clearly stabilize the T-shaped versus the trigonal
pyramidal geometry of the CBiCl2 system. However the energy
difference between the two geometries is fairly small. The
T-shaped geometry of the CBiCl2 unit is strongly stabilized by
the second NfBi coordination. The low energy difference
between the isomers 1a and 1b and the high energy difference
between 1 and 1a show that the stabilization of the square
pyramidal geometry of bismuth is electronic rather than steric
in nature.
The structure of 1 can also be rationalized by means of the
valence shell electron pair repulsion (VSEPR) theory. According

1200 Organometallics, Vol. 26, No. 5, 2007
Soran et al.
Figure 5. Calculated relative energies of different isomers of [2,6-(Me2NCH2)2C6H3]BiCl2, 1.
to this, the Bi atom in 1 has six electron pairs and the structure
is predicted to be based on an octahedron with one lone pair,
hence the square pyramidal shape. However in post-transition
elements such as bismuth the lone pair is not always stere-
ochemically active. This is confirmed by our calculations, which
show that the lone pair of electrons is situated in the energeti-
cally low lying 6s atomic orbital of the bismuth. After removing
one -CH2NMe2 pendent arm, the bismuth atom will have five
electron pairs; hence a geometry based on a trigonal bipyramid
with a lone pair in equatorial position would be expected. That
is in agreement with the calculated structures for 1a and 1b;
however the close to 90° angles are smaller than those expected
from the VSEPR model. After removing the second -CH2NMe2
pendent arm, the bismuth atom will have four electron pairs,
and a distorted tetrahedral geometry with one electron pair would
be expected. The optimization of the geometry of 1c confirms
that, however, the bond angles are close to 90°. We believe
that these values are better explained by the absence of
hybridization of the bismuth atom than by the VSEPR model.
(CDCl3) ) 14 kcal mol-1 (Tc ) 5 °C).23 Similar activation
energies for the dissociation of either one of the Bi-N bonds
(12.3 kcal mol-1 at -5 °C, in toluene-d8) were estimated for
[2,6-(Me2NCH2)2C6H3]Bi[C6H4{C(CF3)2O}-2]4 or for the related
[2-(Me2NCH2)C6H4]BiCl[(SPPh2)2N] (14.7 kcal mol-1 at 25 °C,
in CDCl3).10b
In the crystal of 4 discrete diorganobismuth(III) iodide
molecules cannot be distinguished; instead there is a supramo-
lecular zigzag chain in which alternating (RN1,RN2)- and
(SN1,SN2)-[{2,6-(Me2NCH2)2C6H3}Bi(Me)] units are bridged by
iodine (Figure 6). Selected molecular parameters are given in
Table 2. The bent Bi‚‚‚I‚‚‚Bi bridges (157.19(2)°) are almost
symmetric, and the metal-halogen distances (Bi(1)-I(1′) 3.924-
(1) Å, Bi(1)-I(1′′) 4.022(1) Å) indicate weak interactions similar
to the intermolecular Bi‚‚‚I interaction (3.990 Å), leading to
the chain polymeric association observed in the solid state for
Ar(4-ClC6H4)BiI (Ar ) 2-[(R)-1-(dimethylamino)ethyl]ferro-
cenyl) (cf. the sum of the van der Waals radii, ∑vdW(Bi,I) 4.55
Å).16
Both nitrogen atoms of the ligand are strongly coordinated
to bismuth in a fashion similar to that observed for the dihalides
1-3 (trans N(1)-Bi(1)-N(2) 144.9(3)°). The strength of these
interactions (Bi(1)-N(1) 2.555(8) Å, Bi(1)-N(2) 2.540(8) Å)
is also similar to those found in compounds 1-3. If the weak
Bi‚‚‚I interactions are neglected, the coordination of the metal
center is distorted ψ-trigonal bipyramidal (“seesaw”), with the
nitrogen atoms in apical positions. The vectors of the Bi‚‚‚I
interactions are directed almost trans to the carbon atoms (C(1)-
Bi(1)‚‚‚I(1′) 147.6(2)°, C(13)-Bi(1)‚‚‚I(1′′) 168.9(3)°), thus
completing a distorted octahedral environment around the bis-
muth atom.
Synthesis and Structural Characterization of [2,6-
(Me2NCH2)2C6H3]2BiCl (5). By reacting [2,6-(Me2NCH2)2C6H3]-
Li with BiCl3 in a 2:1 ratio, compound 5 was obtained (Scheme
1).10e The 1H NMR of the precipitate initially isolated from the
reaction mixture indicated contamination with a small amount
of 1. Crystals of compound 5 could be grown only by rapid
removal of the solvent from an etheral solution. Only crystals
of the side product 1 were obtained after slow evaporation from
solutions of 5 in various solvents.
Synthesis and Structural Characterization of [2,6-
(Me2NCH2)2C6H3](Me)BiI (4). In order to obtain a chiral
compound, the dichloride 1 was reacted with methylmagnesium
iodide in a 1:1 molar ratio (Scheme 1). The monoiodide [2,6-
(Me2NCH2)2C6H3]Bi(Me)I (4) was obtained due to the exchange
of chlorine with iodine from the resulting inorganic magnesium
salt. The diiodide 3 was also isolated as a byproduct of this
reaction.
The 1H NMR spectrum of 4 in CDCl3, at room temperature,
showed two singlet signals for the methyl groups attached to
bismuth and nitrogen atoms, respectively, and an AB system
for methylene protons. The aromatic protons appeared as an
unresolved, broad signal. When the 1H NMR spectrum of 4 was
recorded at low temperature, a broadening of the resonance for
the methyl groups attached to the nitrogen atoms was observed
until 5 °C. At -10 °C this signal was completely resolved into
a doublet (see Supporting Information), indicating that both
nitrogen atoms are coordinated to the metal center and the
molecule is frozen to a structure resembling that found in the
solid state (see subsequent discussion). This process corresponds
to the dissociation-recoordination between the nitrogen atoms
and the bismuth atom, with inversion at a three-coordinated
nitrogen atom and rotation around the (H2)C-N bond. The
activation energy of this process was estimated to be ∆Gq-
The NMR spectra of a fresh solution of 5 in CDCl3, at room
temperature, are consistent with equivalent organic groups
(23) Friebolin, H. Basic One- and Two-Dimensional NMR Spectroscopy,
3rd ed.; Wiley-VCH Verlag GmbH: Weinheim, 1998; p 301.

Organobismuth(III) Dihalides
Organometallics, Vol. 26, No. 5, 2007 1201
Figure 7. Molecular structure of the (RN1,SN2)(SN3) isomer of 5
(ORTEP drawing with 30% probability ellipsoids) with the labeling
scheme for the atom positions. Hydrogen atoms have been omitted
for clarity.
Table 3. Selected Bond Distances [Å] and Angles [deg] for
Compound 5
Bi(1)-C(1)
Bi(1)-Cl(1)
Bi(1)-N(1)
Bi(1)-N(2)
N(1)-C(7)
N(1)-C(8)
N(1)-C(9)
N(2)-C(10)
N(2)-C(11)
N(2)-C(12)
2.278(4)
2.6086(13)
2.699(3)
3.070(3)
1.478(5)
1.469(5)
1.460(5)
1.457(5)
1.448(6)
1.451(6)
Bi(1)-C(13)
2.301(4)
Bi(1)-N(3)
N(3)-C(19)
N(3)-C(20)
N(3)-C(21)
N(4)-C(22)
N(4)-C(23)
N(4)-C(24)
3.118(3)
1.449(5)
1.454(6)
1.455(6)
1.455(5)
1.447(6)
1.453(6)
Figure 6. Part of the polymeric chain of 4 (ORTEP drawing with
30% probability ellipsoids) with the labeling scheme for the atom
positions [symmetry equivalent atoms (1-x, -0.5+y, 1.5-z) and
(0.5+x, y, 1.5-z) for I1′ and I1′′, respectively]. Hydrogen atoms,
less those of the methyl group attached to the metal, have been
omitted for clarity.
C(1)-Bi(1)-C(13)
C(1)-Bi(1)-Cl(1)
C(13)-Bi(1)-Cl(1) 85.95(10)
100.13(14) N(1)-Bi(1)-C(1)
96.42(11)
69.64(12)
81.03(12)
158.72(8)
166.82(10)
66.70(10)
82.78(8)
N(1)-Bi(1)-C(13)
N(1)-Bi(1)-Cl(1)
N(2)-Bi(1)-C(13)
N(2)-Bi(1)-C(1)
N(2)-Bi(1)-Cl(1)
N(2)-Bi(1)-N(1)
N(2)-Bi(1)-N(3)
C(7)-N(1)-C(8)
C(7)-N(1)-C(9)
C(8)-N(1)-C(9)
Bi(1)-N(1)-C(7)
Bi(1)-N(1)-C(8)
Bi(1)-N(1)-C(9)
152.66(11) N(3)-Bi(1)-C(1)
64.08(10)
74.60(8)
110.94(10) N(3)-Bi(1)-N(1)
127.71(9)
108.9(3)
111.8(3)
109.5(3)
100.3(2)
118.8(3)
107.2(3)
N(3)-Bi(1)-C(13)
N(3)-Bi(1)-Cl(1)
Table 2. Selected Bond Distances [Å] and Angles [deg] for
Compound 4a
107.06(9)
Bi(1)-C(1)
Bi(1)-I(1′)
Bi(1)-N(1)
N(1)-C(7)
N(1)-C(8)
N(1)-C(9)
2.204(8)
3.924(1)
2.555(8)
1.472(12)
1.474(13)
1.475(13)
Bi(1)-C(13)
Bi(1)-I(1′′)
Bi(1)-N(2)
N(2)-C(10)
N(2)-C(11)
N(2)-C(12)
2.224(10)
4.022(1)
2.540(8)
1.482(12)
1.482(12)
1.480(12)
C(19)-N(3)-C(20) 110.3(4)
C(19)-N(3)-C(21) 109.7(4)
C(20)-N(3)-C(21) 110.2(4)
Bi(1)-N(3)-C(19)
Bi(1)-N(3)-C(20)
Bi(1)-N(3)-C(21)
81.3(2)
125.3(3)
111.7(2)
C(10)-N(2)-C(11) 111.4(4)
C(10)-N(2)-C(12) 111.5(4)
C(11)-N(2)-C(12) 110.6(4)
C(22)-N(4)-C(23) 111.7(4)
C(22)-N(4)-C(24) 111.0(4)
C(23)-N(4)-C(24) 111.8(4)
C(1)-Bi(1)-C(13)
N(1)-Bi(1)-C(1)
N(1)-Bi(1)-C(13)
C(7)-N(1)-C(8)
C(7)-N(1)-C(9)
C(8)-N(1)-C(9)
Bi(1)-N(1)-C(7)
Bi(1)-N(1)-C(8)
Bi(1)-N(1)-C(9)
91.2(4)
71.9(3)
93.1(4)
110.1(8)
109.6(8)
110.5(8)
104.2(5)
111.4(6)
111.1(6)
N(1)-Bi(1)-N(2)
N(2)-Bi(1)-C(1)
N(2)-Bi(1)-C(13)
C(10)-N(2)-C(11)
C(10)-N(2)-C(12)
C(11)-N(2)-C(12)
Bi(1)-N(2)-C(10)
Bi(1)-N(2)-C(11)
Bi(1)-N(2)-C(12)
144.9(3)
73.0(3)
87.9(4)
109.5(7)
109.0(8)
109.2(8)
104.9(5)
106.1(5)
117.8(6)
Bi(1)-N(2)-C(10)
Bi(1)-N(2)-C(11)
Bi(1)-N(2)-C(12)
93.0(2)
112.4(3)
116.8(3)
(C,N) ligand, with the nitrogen of the second arm twisted far
from the metal center. The compound crystallizes as a 1:1
mixture of (RN1,SN2)(SN3) and (SN1,RN2)(RN3) isomers, the former
being depicted in Figure 7. Selected molecular parameters are
given in Table 3.
a Symmetry equivalent atoms (1-x, -0.5+y, 1.5-z) and (0.5+x, y, 1.5-
z) for I1′ and I1′′, respectively.
attached to bismuth. The broad singlet resonances observed for
the methyl and methylene protons, respectively, suggest a
fluxional behavior. Time-dependent H NMR spectra starting
The Bi-N vectors lie almost trans to a normal covalent
bond: N(1)-Bi(1)-Cl(1) 158.72(8)°, N(2)-Bi(1)-C(13) 152.66-
(11)°, and N(3)-Bi(1)-C(1) 166.82(10)°. The Bi(1)-N(1) and
the Bi(1)-Cl(1) bonds are trans to each other and are weaker
(2.699(3) Å) and stronger (2.6086(13) Å), respectively, with
respect to the analogous trans-N-Bi-Cl system in the related
[2-(Me2NCH2)C6H4]2BiCl (Bi-N 2.570(5) Å, Bi-Cl 2.667(2)
Å).8 The other two intramolecular bismuth-nitrogen interactions
are considerably weaker (Bi(1)-N(2) 3.070(3) Å, Bi(1)-N(3)
3.118(3) Å), but still shorter than the sum of the van der Waals
radii for Bi and N atoms. A similar value was also found for
the second intramolecular Bi-N interaction (3.047(5) Å) in
[2-(Me2NCH2)C6H4]2BiCl,8 while the Bi-N interactions in the
1
from crystals of compound 5 proved that a disproportionation
process to 1 and R3Bi occurs in CDCl3 solution. The molar ratio
between the signals corresponding to the methylene protons of
compounds 1 and 5 increases during 2 days from 1:340 to 1:13.
A single-crystal X-ray diffraction study revealed that in the
molecules of 5 only three of four available nitrogen atoms
coordinate to bismuth. In contrast to the dihalides 1-3 and
compound 4, the ligand that exhibits a (N,C,N)-coordination
pattern in 5 has both nitrogen atoms on the same side of the
plane of the aromatic ring. The other organic group acts as a

1202 Organometallics, Vol. 26, No. 5, 2007
Table 4. Data Collection and Structure Refinement Details for Compounds 1-5
Soran et al.
1
2
3
4
5
chemical formula
cryst habit
cryst size [mm]
cryst syst
space group
a [Å]
C12H19BiCl2N2
colorless block
0.29 × 0.22 × 0.18
triclinic
P1h
8.2936(7)
10.2996(8)
10.3432(8)
66.9920(10)
75.1250(10)
81.9120(10)
785.18(11)
2
C12H19BiBr2N2
colorless block
0.43 × 0.17 × 0.12
orthorhombic
Pbcn
16.177(4)
11.491(3)
8.4265(19)
90
90
90
1566.4(7)
4
2.375
C12H19BiI2N2
yellow block
0.28 × 0.17 × 0.13
orthorhombic
Pbcn
16.278(3)
11.848(2)
8.8883(16)
90
90
90
1714.2(5)
4
2.534
C13H22BiIN2
colorless block
0.25 × 0.19 × 0.17
orthorhombic
Pbca
11.9840(17)
13.3474(19)
20.537(3)
90
90
90
3284.9(8)
8
2.193
C24H38BiClN4
colorless block
0.24 × 0.22 × 0.13
monoclinic
P1h 21/n
9.9668(7)
17.2075(12)
15.5319(11)
90
94.7380(10)
90
2654.7(3)
4
b [Å]
c [Å]
R [deg]
â [deg]
γ [deg]
U [Å3]
Z
Dc [g cm-3
M
]
1.993
471.17
444
24
1.569
627.01
1240
24
560.09
1032
24
654.07
1176
24
542.21
2000
24
F(000)
T [°C]
2θmax [deg]
56.26
11.550
6764
3496
0.0253
0.0238
0.0516
158
52.74
52.74
52.74
52.74
6.759
21 075
5423
0.0459
0.0310
0.0596
279
µ(Mo KR) [mm-1
]
16.341
11 626
1609
0.0673
0.0340
0.0868
81
13.872
12 755
1761
0.0406
0.0245
0.0482
82
12.599
24 755
3356
0.0507
0.0483
0.0968
159
no. of reflns measd
no. of unique reflns
Rint
Ra (I > 2σ(I))
wRb (F2, all reflns)
no. of params
no. of restraints
Sc
0
0
0
0
0
1.021
0.965, -1.211
1.111
1.247, -1.551
1.138
0.954, -1.128
1.159
2.805, -1.318
1.043
0.993, -0.503
∆F, max., min. [e Å-3
]
b
2
2
2
2
2
2
c
a R1 ) ∑ ||Fo| - |Fc||/∑|Fo|. wR2 ) {∑[w(Fo - Fc )2]/∑[w(Fo )2]}1/2. w ) 1/[σ2(Fo ) + (w1P)2 + w2P], where P ) [2Fc + Max(Fo )]/3. GooF ) S
2
2
) {∑[w(Fo - Fc )2]/(n - p)}1/2, where n is the number of reflections and p is the total number of parameters refined.
1
temperature H NMR spectra were recorded on a Bruker Avance
dibismuthane [2,6-(Me2NCH2)2C6H3]4Bi2 are even weaker
(range 3.183(11)-3.370(10) Å).10e If all three metal-nitrogen
interactions are taken into account, a distorted octahedral
(N,C,N)(C,N)BiX core can be considered, with the deviations
of the bond angles at the metal atom from the ideal values
mainly due to the constraints imposed by the coordinated amine
arms (Table 3).
In the crystal of 5 the discrete monomeric molecular units
are separated by normal van der Waals distances between heavy
atoms. However, a closer inspection of the crystal structure
revealed that between the halogen atom and the para hydrogen
atom of the (N,C,N) ligand of a neighboring molecule a weak
intermolecular interaction is established [Cl‚‚‚Haryl 2.958 Å, at
the limit of a van der Waals contact, ∑vdW(Cl,H) ca. 3.0 Å].16
This results in a supramolecular chain polymer, with alternating
(RN1,SN2)(SN3) and (SN1,RN2)(RN3) molecular units.
DPX 200 instrument. Chemical shifts are reported in δ units (ppm)
relative to the residual peak of the deuterated solvent (ref CHCl3:
1H 7.26, 13C 77.0 ppm).
Synthesis of [2,6-(Me2NCH2)2C6H3]BiBr2 (2). A solution of
compound 1 (1.0 g, 2.1 mmol) in CH2Cl2 (20 mL) was vigorously
stirred for 48 h with a solution of KBr (1.0 g, 8.4 mmol) in EtOH
(25 mL) and distilled water (15 mL). Additional distilled water
(50 mL) was then added, and the colorless organic phase was
removed with a syringe. The aqueous phase was washed with CH2-
Cl2 (25 mL). The organic phases were washed with distilled water
(2 × 25 mL) and then dried over anhydrous Na2SO4. The solution
was filtered off and the solvent removed in vacuum. The remaining
white powder was washed with hexane (4 × 10 mL) and then dried
in vacuum to give compound 2. Yield: 1.04 g (88%), mp 261 °C
(dec). Anal. Calcd for C12H19BiBr2N2 (MW 560.08): C, 25.73; H,
1
3.42; N, 5.00. Found: C, 25.55; H, 3.34; N, 5.12. H NMR (360
MHz, CDCl3): 2.98 (12H, s, CH3), 4.50 (4H, s, CH2), 7.51 (1H, t,
Experimental Section
Ar-H4, 3JHH ) 7.5 Hz), 7.73 (2H, d, Ar-H3,5, 3JHH ) 7.5 Hz). 13
C
NMR (90 MHz, CDCl3): 48.42 (s, CH3), 69.24 (s, CH2), 128.39
(s, Ar-C3,5), 129.52 (s, Ar-C4), 151.84 (s, Ar-C2,6), 204.93 (s,
Ar-C1). Mass spectrum (EI, 70 eV): m/z (relative intensity, %)
480 (100) [M+ - Br], 400 (9) [RBi+], 209 (10) [Bi+], 191 (71)
[R+] [R ) 2,6-(Me2NCH2)2C6H3].
General Procedures. 1,3-Bis[(dimethylamino)methyl]benzene,
1,3-(Me2NCH2)2C6H4,4andthemonochloride[2,6-(Me2NCH2)2C6H3]2-
BiCl (5),10e were obtained according to reported literature methods.
Details for the preparation and spectroscopic characterization of
the dichloride [2,6-(Me2NCH2)2C6H3]BiCl2 (1) (see also ref 9) are
included in the Supporting Information. Bismuth trichloride was
sublimated in vacuum and kept under argon. All other reagents
were obtained from Aldrich or Merck and were used as received.
All the syntheses were carried out under an argon atmosphere using
dried solvents, distilled under argon prior to use.
Instrumentation. Elemental analyses were carried out with a
Perkin-Elmer 2400 apparatus. Melting points were measured on
an Electrothermal 9200 apparatus and are not corrected. Mass
spectra were recorded on Finnigan MAT 8200 (EI, CI) or Bruker
Esquire LC (ESI) instruments. 1H, 13C, and 2D NMR spectra were
recorded on Bruker Avance DPX 200 and 360, DRX 400, or DRX
600 instruments in CDCl3 solutions, at room temperature. Variable-
Synthesis of [2,6-(Me2NCH2)2C6H3]BiI2 (3). A similar proce-
dure to that for compound 2 was used, with compound 1 (1.0 g,
2.1 mmol) in CH2Cl2 (40 mL) and KI (1.7 g, 10.2 mmol) in EtOH
(25 mL) and distilled water (15 mL). Compound 3 was isolated as
a yellow powder. Yield: 1.26 g (91%), mp 203 °C (dec). Anal.
Calcd for C12H19BiI2N2 (MW 654.09): C, 22.04; H, 2.93; N, 4.28.
1
Found: C, 21.83; H, 2.78; N, 4.05. H NMR (360 MHz, CDCl3):
3.12 (12H, s, CH3), 4.55 (4H, s, CH2), 7.56 (1H, t, Ar-H4, 3JHH
)
7.5 Hz), 7.75 (2H, d, Ar-H3,5, 3JHH ) 7.5 Hz). 13C NMR (90 MHz,
CDCl3): 50.95 (s, CH3), 71.31 (s, CH2), 128.65 (s, Ar-C3,5), 129.73
(s, Ar-C4), 152.46 (s, Ar-C2,6), 197.91 (s, Ar-C1). Mass spectrum
(EI, 70 eV): m/z (relative intensity, %) 527 (100) [M+ - I], 400

Organobismuth(III) Dihalides
Organometallics, Vol. 26, No. 5, 2007 1203
(29) [RBi+], 209 (7) [Bi+], 191 (34) [R+] [R ) 2,6-(Me2-
NCH2)2C6H3].
Crystallographic Data Centre, 12 Union Road, Cambridge CB2
1EZ,UK;fax: (+44)1223-336-033;ore-mail: deposit@ccdc.cam.ac.uk).
Computational Details for DFT Calculations. Density func-
tional calculations were carried out using the Amsterdam Density
Functional program suite ADF 2005.01.26 Scalar relativistic cor-
rections were included via the ZORA method for all calculations.27
The generalized gradient approximation was employed, using the
local density approximation of Vosko, Wilk, and Nusair28 together
with the nonlocal exchange correction by Becke29 and nonlocal
correlation corrections by Perdew.30 TZP basis sets were used with
triple-ú accuracy sets of Slater-type orbitals and two polarization
functions added to the main group atoms. The cores of the atoms
were frozen up to 1p for C and N, 2p for Cl, and 5p for Bi. All
quoted electronic structure data have gradient corrections applied
after the SCF cycles. For comparing the relative energies of the
different isomers the SCF energies were used.
Synthesis of [2,6-(Me2NCH2)2C6H3](Me)BiI (4). A solution of
MeMgI [Mg turnings (0.103 g, 4.24 mmol) and MeI (0.603 g, 4.24
mmol)] in Et2O (25 mL) was added dropwise to a suspension of
compound 1 (2.0 g, 4.24 mmol) in Et2O. The reaction mixture was
stirred at room temperature for 10 h to give a yellow, ethereal
solution and a yellow precipitate. Distilled water (80 mL) was then
added, and the whole mixture was filtered through a glass frit to
give a yellow solid and a yellow organic phase. The yellow
precipitate was investigated and turned out to be compound 3. The
yellow organic phase was separated and dried over anhydrous Na2-
SO4. Upon removal of the solvent, compound 4 was obtained as
pale yellow powder. Yield: 0.77 g (34%), mp 210 °C. Anal. Calcd
for C13H22BiIN2 (MW 542.22): C, 28.80; H, 4.09; N, 5.17.
1
Found: C, 28.63; H, 3.96; N, 5.34. H NMR (200 MHz, CDCl3,
20 °C): 1.68 (3H, s, Bi-CH3), 2.81 (12H, s, N-CH3), AB spin
2
system with A at 3.90 and B at 4.06 ppm (4H, CH2, JHH ) 14.6
Acknowledgment. Financial support from National Uni-
versity Research Council (CNCSIS, Romania; Research Project
Nos. A-709/2006 and TD-100/2006) and the Ministry of
Education and Research of Romania (Excellency Research
Program, project CEx-05-D11-16/2005) is greatly appreciated.
We thank Universitat Bremen for providing research facilities
and financial support during short-term research stays. We also
thank the National Center for X-Ray Diffraction and Dr. Richard
Varga (“Babes-Bolyai” University, Cluj-Napoca, Romania) for
the support in the solid-state structure determinations. We thank
the Oxford Supercomputing Centre for facilities and support.
G.B. thanks the Alexander von Humboldt Foundation for a
Feodor Lynen Fellowship.
Hz), 7.44 (3H, s, br, C6H3). 1H NMR (200 MHz, CDCl3, -10 °C):
1.64 (3H, s, Bi-CH3), 2.72 (6H, s, N-CH3), 2.85 (6H, s, N-CH3),
AB spin system with A at 3.89 and B at 4.04 ppm (4H, CH2, 2JHH
) 14.6 Hz), 7.42 (3H, s, br, C6H3). 13C NMR (50 MHz, CDCl3, 20
°C): 38.41 (s, Bi-CH3), 47.77 (s, N-CH3), 68.85 (s, CH2), 127.26
(s, Ar-C3,5), 128.71 (s, Ar-C4), 148.40 (s, Ar-C2,6), 181.18 (s,
Ar-C1). Mass spectrum (EI, 70 eV): m/z (relative intensity, %)
527 (57) [M+ - Me], 481 (17) [M+ - Me3N], 415 (100) [M+
-
I], 400 (82) [RBi+], 209 (13) [Bi+], 191 (64) [R+]. Mass spectrum
(ESI, positive, MeOH/CH2Cl2): m/z, (relative intensity, %) 543
[M+], 527 [M+ - Me], 415 [M+ - I], 400 [RBi+], 191 [R+]. Mass
spectrum (ESI, negative, MeOH/CH2Cl2): m/z (relative intensity,
%) 209 [Bi-], 127 [I-].
Crystallography. Colorless crystals of compounds 1 were grown
by slow diffusion, using CH2Cl2/hexane systems. Colorless crystals
of compound 2 and yellow crystals of compound 3 were grown by
cooling hot, saturated DMSO solutions. Pale yellow crystals of
compound 4 were grown by slow diffusion using a CH2Cl2/
petroleum ether system. Colorless crystals of compound 5 were
obtained by fast removal of the solvent from an Et2O solution. The
crystals were attached to a cryo loop. Data were collected at room
temperature on a Bruker SMART APEX diffractometer, using
graphite-monochromated Mo KR radiation (λ ) 0.71073 Å). Scan
type ω and φ. Absorption corrections: multiscan. The structures
were solved by direct methods and refined on F2 using the program
SHELXL-97.24 All non-hydrogen atoms were anisotropically
refined. The hydrogen atoms were refined with a riding model and
a mutual isotropic thermal parameter. Further details on the data
collection and refinement methods can be found in Table 4. The
drawings were created with the Diamond program.25 CCDC-
619307-619311 contain the supplementary crystallographic data
for this paper. These data can be obtained free of charge via
www.ccdc.cam.ac.uk/conts/retrieving.html (or from the Cambridge
Supporting Information Available: Details of the synthesis
and spectroscopic characterization of compounds 1 and 5; X-ray
crystallographic data in CIF format for 1-5; Cartesian coordinates
of the modeled structures of complexes 1-1d; figures representing
the molecular structures of compounds 2 and 3, as well as the
supramolecular architectures in the crystals of compounds 1, 3, and
5; variable-temperature 1H NMR spectra of compound 4. This
materialisavailablefreeofchargeviatheInternetathttp://pubs.acs.org.
OM0611608
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