New mercury(II) and silver(I) complexes containing NHC metallacrown ethers with the π-π stacking interactions

Article abstract of DOI:10.1016/j.jorganchem.2007.09.027

The oligoether-linked bis-benzimidazolium salt 1,1′-[1,2-ethanediylbis(oxy-1,2-ethanediyl)]bis[(3-^secbutyl)benzimidazolium-1-yl]iodide (H₂L¹ · I₂), 1,1′-[1,2-ethanediylbis(oxy-1,2-ethanediyl)]bis[(3-ethyl)benzimidazolium-1-yl]iodide (H₂L² · I₂) and 1,1′-[1,2-ethanediylbis(oxy-1,2-ethanediyl)]bis[(3-^secbutyl)benzimidazolium-1-yl]hexafluorophosphate (H₂L¹ · (PF₆)₂) and their three new mercury(II) and silver(I) complexes containing NHC metallacrown ethers, HgL¹ · (Hg₂ · I₆) (1), HgL² · I₂ (2) and AgL¹ · PF₆ (3) were prepared and characterized. In the packing diagrams of H₂L² · I₂, 1, 2 and 3 benzimidazole ring head-to-tail π-π stacking interactions are observed.

Full text of DOI:10.1016/j.jorganchem.2007.09.027

Available online at www.sciencedirect.com
Journal of Organometallic Chemistry 692 (2007) 5671–5679
www.elsevier.com/locate/jorganchem
New mercury(II) and silver(I) complexes containing NHC
metallacrown ethers with the p–p stacking interactions
*
Qing-Xiang Liu , Xiao-Jun Zhao, Xiu-Mei Wu, Jian-Hua Guo, Xiu-Guang Wang
Key Laboratory of Molecular Structure and Materials Performance, College of Chemistry and Life Science, Tianjin Normal University,
Tianjin 300387, PR China
Received 17 August 2007; received in revised form 20 September 2007; accepted 27 September 2007
Available online 5 October 2007
Abstract
The oligoether-linked bis-benzimidazolium salt 1,1 -[1,2-ethanediylbis(oxy-1,2-ethanediyl)]bis[(3- butyl)benzimidazolium-1-yl]iodide
0
sec
1
0
2
0
(
(
H
2
L Æ I
2
), 1,1 -[1,2-ethanediylbis(oxy-1,2-ethanediyl)]bis[(3-ethyl)benzimidazolium-1-yl]iodide (H L Æ I ) and 1,1 -[1,2-ethanediylbis-
2
2
sec
1
oxy-1,2-ethanediyl)]bis[(3- butyl)benzimidazolium-1-yl]hexafluorophosphate (H L Æ (PF ) ) and their three new mercury(II) and sil-
ver(I) complexes containing NHC metallacrown ethers, HgL Æ (Hg
characterized. In the packing diagrams of H
2007 Published by Elsevier B.V.
2
6 2
1
2
1
2
Æ I
6 2 6
) (1), HgL Æ I (2) and AgL Æ PF (3) were prepared and
L Æ I , 1, 2 and 3 benzimidazole ring head-to-tail p–p stacking interactions are observed.
2 2
2
ꢀ
Keywords: Carbene complex; Mercury; Silver; p–p stacking interactions
1
. Introduction
Pd, Pt, Cu, Au, Rh, Ir and Ru carbene complexes, such a
route affords a convenient method for the preparation of
these metal carbene complexes [6]. Also metal–NHC
complexes have been demonstrated to be efficient catalysts
for some organic reactions, such as Heck, Suzuki, Kumada
couplings, and olefin metathesis [7]. N-heterocyclic carbene
complexes have shown to be remarkably stable toward
heat, air, and moisture [8].
Since the discovery of free N-heterocyclic carbene
(
2
NHC) [1], organometallic chemistry based on imidazol-
-ylidene (imy) or benzimidazol-2-ylidene (bimy) have been
receiving considerable attention. The primary characteris-
tic of NHCs is that they are strong r-donor ligands, which
can bind firmly to different metal ions with various oxida-
tion states [2], and a variety of related transition-metal
complexes have been synthesized through deprotonation
Polyether chain phosphine containing metallacrown
ethers have been widely studied, because in the complexes
the presence of weakly binding oxygen-donor groups can
significantly increase the catalytic performance of these
systems [9]. The NHC complexes containing metallacrown
ethers have structural similarity with related phosphate
complexes, and they have potential application as a
catalyst and a phase-transfer reagent, therefore, we are
interested in the compounds. In the paper, we report the
synthesis, structural characterization of new mercury(II)
and silver(I) complexes containing NHC metallacrown
0
of N,N -disubstituted imidazolium (or benzimidazolium)
salts [3]. Among these metal–NHC complexes, some
reports on the imidazol-2-ylidene (or benzimidazol-2-yli-
dene) complexes of Hg(II) and Ag(I) have appeared [4].
A new discovery shows that Ag(I)–carbene complexes
can be used as effective antimicrobial agents [5], and they
are also good carbene transfer agents for synthesis of Ni,
1
*
ethers with a flexible bridging chain, HgL Æ (Hg Æ I ) (1),
HgL Æ I (2) and AgL Æ PF (3).
2 6
Corresponding author. Tel.: +86 13820172297.
2
6
2
1
E-mail address: qxliu@eyou.com (Q.-X. Liu).
0
022-328X/$ - see front matter ꢀ 2007 Published by Elsevier B.V.
doi:10.1016/j.jorganchem.2007.09.027

5672
Q.-X. Liu et al. / Journal of Organometallic Chemistry 692 (2007) 5671–5679
2
. Results and discussion
2
O
O
N
N
N
2
.1. Synthetic strategy
Hg
I
N
0
The bis-benzimidazolium salts, 1,1 -[1,2-ethanediylbis
sec
HgI2
sec-C H9
sec-C H9
H L1 I2
4
4
(
oxy-1,2-ethanediyl)]bis[(3- butyl)benzimidazolium-1-yl]
iodide (H L Æ I ) and 1,1 -[1,2-ethanediylbis(oxy-1,2-etha-
nediyl)]bis[(3-ethyl)benzimidazolium-1-yl]iodide (H L Æ I )
2
1
0
KOBut
2
2
2
2
I
I
I
2
2
Hg
Hg
were prepared from benzimidazole by stepwise alkylation
with 1-haloalkane followed by 1,2-bis(2-iodoethoxy)ethane
I
I
0
in sequence, and 1,1 -[1,2-ethanediylbis(oxy-1,2-etha-
1
sec
nediyl)]bis[(3- butyl)benzimidazolium-1-yl]hexafluorophos-
phate (H L Æ (PF ) ) was obtained by treatment of H L Æ I
2
1
1
2
6 2
2
with ammonium hexafluorophosphate in methanol (Scheme
O
I
O
I
KOBut
N
N
N
1
2
1
1
). Precursors H L Æ I , H L Æ I and H L Æ (PF ) are sta-
H2L2
I2
2
2
2
2
2
6 2
Hg
ble to air and moisture, and soluble in polar organic solvents
such as dichloromethane, acetonitrile, methanol, scarcely
soluble in benzene, and insoluble in diethyl ether, petroleum
Hg(OAc)2
N
C H
C H
2 5
2
5
1
1
2
ether and water. In the H NMR spectra of H L Æ I ,
2
2
2
1
H L Æ I and H L Æ (PF ) the benzimidazolium proton sig-
2
2
2
6 2
1
nals (NCHN) appear at d = 11.43 ppm for H L Æ I ,
1.50 ppm for H L Æ I and 11.40 ppm for H L Æ (PF ) ,
2 2 2 6 2
2
2
2
1
O
O
1
Ag O
N
N
2
1
which are consistent with the chemical shifts of known
imidazolium salts or benzimidazolium salts [3].
Ag
H L PF
2
6
N
N
PF6
1
2
The H L Æ I or H L Æ I was treated with HgI or
2
2
2
2
2
sec-C H
9
sec-C4H9
t
4
Hg(OAc) in the presence of KOBu in the solution of
2
3
CH CN and THF to afford macrocycle discarbene com-
3
1
2
plexes HgL Æ (Hg Æ I ) (1) and HgL Æ I (2). The
2
6
2
Scheme 2. Preparation of complexes 1, 2 and 3.
1
AgL Æ PF (3) was prepared by the reaction of
6
1
H L Æ (PF ) with Ag O in CH Cl solution (Scheme 2).
2
6 2
2
2
2
The complexes 1, 2 and 3 are stable in air and moisture,
tra of 1, 2 and 3, the disappearance of the resonances for
the benzimidazolium protons (NCHN) shows the forma-
tion of the expected metal carbene complexes, and the
chemical shifts of other hydrogens are similar to those of
corresponding precursors. In C NMR spectra the signals
for the carbene carbon appears at 175 ppm for 1, 173 ppm
and soluble in DMSO and CH Cl , and insoluble in diethyl
2
2
ether, hydrocarbon solvents and water. Complex 3 is light-
sensitive in solution, but light-stable as solid. The forma-
1
13
tion of the metal carbene complexes was confirmed by H
1
3
1
NMR and C NMR spectroscopy. In the H NMR spec-
NaH
O
O
I
O
O
I
N
N
2I-
RX
N
N
R
HN
N
R N
N
R
H2L1 I2 R = sec-C H9
4
H2L2 I2 R =C2H5
O
O
N
NH PF6
N
H2L1 I2
4
N
N
2PF6
sec-C H9
sec-C H9
4
4
1
H L PF
2
6
1
2
1
Scheme 1. Preparation of precursors H
2
L Æ I
2
, H
2
L Æ I
2
and H
2
L Æ (PF
6
)
2
.

Q.-X. Liu et al. / Journal of Organometallic Chemistry 692 (2007) 5671–5679
5673
for 2, which are characteristic for carbene metal complexes
4a,4b,4c,4d,4e], but in complex 3, the resonances for the
hydrogen bonds expand above mentioned 2D supramolec-
ular layers into 3D supramolecular architecture.
[
carbene carbon were not observed. The absence of the car-
bene carbon resonance is not unusual, and this phenome-
non has been reported for some silver–carbene
complexes, and given a reason of the fluxional behavior
of the NHCs complexes [10].
The pale yellow crystals of 1 and 2 Æ CH Cl suitable for
2
2
X-ray diffraction were grown by slow diffusion of diethyl
ether into their CH Cl /DMSO solution. The white crystals
2
2
of 3 were obtained by evaporating slowly its CH Cl solu-
2
2
tion at room temperature.
In each cation of 1 a 13-membered NHC metallacrown
ether is formed by a didentate chelate bis(carbene) ligand
with a long flexible linkage and a mercury(II) as shown
in Fig. 2. The both benzimidazole rings form a dihedral
angle of 39ꢁ. Two sec-butyl chains point to contrary direc-
tions, and the cationic unit possesses a trans-configuration.
Each mercury atom is coordinated by two carbene-car-
bons, two oxygen atoms from flexible linkage and two
iodine atoms from two anionic units to form a distorted
octahedron arrangement. The C(11A)–Hg(1A)–C(28A) is
approximately linear, with the Hg–C(carbene) bond dis-
2
2
.2. Structure of precursor H L Æ I , complexes 1, 2 and 3
2
2
2
The pale yellow crystals of H L Æ I suitable for X-ray
diffraction were obtained by evaporating slowly its
CH Cl /CH CN solution at room temperature. In molecu-
lar structure of H L Æ I both benzimidazoles are parallel,
and two ethyl chains point to contrary directions (Fig. 1).
The internal ring angle (N–C–N) at the carbene center is
10.8(4)ꢁ. Analysis of the crystal packing of H L Æ I
2
2
2
2
3
2
2
2
2
1
2
2
revealed that the 2D supramolecular layers are formed by
head-to-tail p–p interactions from intermolecular benz-
imidazole rings with the inter-planar separation of
˚
tances of 2.072(11) and 2.078(12) A, and the bond angel
of 175.9(4)ꢁ, respectively. These values are comparable to
the corresponding values reported for other mercury(II)
carbene complexes [4a,4b,4c,4d,4e]. The Hgꢀ ꢀ ꢀO separa-
˚ ˚
3
.392 A (center-to-center separation: 3.535 A) [11]. In
addition, each anionic iodine as a bridge joins two cationic
units via Iꢀ ꢀ ꢀH–C hydrogen bonds (C(1B)–H(1B)ꢀ ꢀ ꢀ
I(1A)ꢀ ꢀ ꢀH(12B)–C(12B), Iꢀ ꢀ ꢀH separations being 3.019
˚
tions are 2.827(10) and 2.799(10) A, respectively, which
are within the range of distances observed in HgX crown
2
˚
and 3.155 A, and Iꢀ ꢀ ꢀH–C angles being 132.3 and 163.4ꢁ,
ether and polyethylene glycol complexes [12]. The Hgꢀ ꢀ ꢀI
˚
and Hꢀ ꢀ ꢀIꢀ ꢀ ꢀH angles being 123.6ꢁ, respectively) (Fig. 1).
distance of ca. 3.4 A are longer than normal values (regular
˚
The each cationic unit is connected with four anionic
Hg–I bond length being 2.7–2.9 A) [4e] but shorter than the
˚
iodines
(
(
via
four
Iꢀ ꢀ ꢀH–C
hydrogen
bonds
sum of the van der Waals radii (3.7 A), showing a weak
I(1A)ꢀ ꢀ ꢀH(1B)–C(1B), I(1C)ꢀ ꢀ ꢀH(12C)–C(12C), I(1B)ꢀ ꢀ ꢀH
interaction between cationic units and anionic units. The
12D)–C(12D) and I(1D)ꢀ ꢀ ꢀH(1AB)–C(1AB)), respectively.
The adjacent two cationic units are held together by two
bridging iodines via Iꢀ ꢀ ꢀH–C hydrogen bonds. These
2
Fig. 1. Intermolecular Iꢀ ꢀ ꢀH–C interactions in H
2
L Æ I
2
. The unrelated
Fig. 2. Perspective view of 1 and anisotropic displacement parameters
depicting 30% probability. Hydrogen atoms have been omitted for clarity.
hydrogen atoms have been omitted for clarity.

5674
Q.-X. Liu et al. / Journal of Organometallic Chemistry 692 (2007) 5671–5679
2
internal ring angle (N(1)–C(11)–N(2)) at the carbene center
is 108.7ꢁ.
sponding precursor H L Æ I (110.8(4)ꢁ) and similar to
2
2
those of some known mercury complexes. The relative
˚
˚
In the anionic unit of 1 two mercury atoms and six iodine
atoms (two bridging iodines I(3A) and I(3B), and four ter-
minal iodines I(1A), I(2A), I(1B), I(2B)) form the building
long Hgꢀ ꢀ ꢀO separations of 3.195(5) A and 4.134(6) A
show no Hgꢀ ꢀ ꢀO interactions.
In the crystal packing of complex 2 like the cation of 1,
1D infinite chains are also formed through the head-to-tail
p–p stacking interactions from inter-molecular benzimid-
2
ꢁ
unit [Hg I ] (Fig. 2). The coplanar four atoms Hg(2A),
2
6
I(3A), Hg(2B) and I(3B) form a quadrangle Hg I arrange-
2
2
˚
ment (I(3A)–Hg(2A)–I(3B) = 95.3ꢁ and Hg(2A)–I(3A)–
Hg(2B) = 84.6ꢁ). The four terminal iodine atoms (1A),
I(1B), I(2A) and I(2B) lie in both flanks of the quadrangle
plane (I(1A)–Hg(2A)–I(2A) = 122.9ꢁ), respectively. The
distances of terminal iodine and mercury (Hg(2A)–
azole rings, with the inter-planar separation of 3.442 A
(center-to-center separation: 4.295 A). In addition, the
˚
intermolecular Iꢀ ꢀ ꢀH–C hydrogen bonds (Iꢀ ꢀ ꢀH separa-
˚
tion = 3.213 A, Iꢀ ꢀ ꢀH–C angle = 168.6ꢁ) between 1D infi-
nite chains are observed (Fig. 3), which expand the above
1D infinite chains into 2D supramolecular layers. Thus,
2D supramolecular layers are stabilized by aromatic p–p
stacking interactions from benzimidazole rings and
Iꢀ ꢀ ꢀH–C hydrogen bonds from inter-molecules in 2.
˚
˚
I(1A) = 2.674(1) A and Hg(2A)–I(2A) = 2.694(1) A) are
relatively shorter than those of bridging iodine and mercury
(
Hg(2A)–I(3A) = 2.8652(12) and Hg(2A)–I(3B) = 3.092(4)
˚
˚
A). The Hgꢀ ꢀ ꢀHg separation of 4.016 A shows no metal–
metal interactions. The both quadrangle Hg I planes from
Similar to 1 and 2, complex 3 contains also a macrocycle
NHC metallacrown ether formed by a didentate chelate
bis(carbene) ligand with a long flexible linkage and a sil-
ver(I) as shown in Fig. 4. The both benzimidazole rings
within each molecule form a dihedral angle of 69.2ꢁ. Two
sec-butyl chains point to contrary directions, and the cat-
ionic unit possesses a trans-configuration, comparable to
the cationic configuration of 1. The coordination geometry
on the silver atom is nearly linear with the Ag–carbene
2
2
both different anionic units lying in both flanks of cationic
unit form a dihedral angle of 67.8ꢁ. It was known that mer-
cury(II) ions have a strong tendency to form complexes,
principally linear two-coordinate [HgX ], or tetrahedral
2
2
ꢁ
four-coordinate [HgX ]
systems [4a,4b,4c,4d,4e], but
4
2
ꢁ
[
Hg I ] is a rare anionic complex.
2
6
An interesting feature in the packing diagrams of 1 is
that 1D chains are formed by the head-to-tail p–p stacking
˚
˚
interactions from inter-molecular benzimidazole rings, with
bond distances of 2.088(6) A and 2.090(6) A, and with
the bond angle C(11)–Ag(1)–C(18) of 174.0(2)ꢁ. The inter-
nal ring angle (N(1)–C(7)–N(2)) at the carbene center is
105.8(5)ꢁ. These values are quite normal when compared
to the corresponding values reported for other NHC silver
complexes [4f,4g,4h,4i,4j,4k,4l,4m,4n,4o,4p,4q,4r]. The
˚
the inter-planar separation of 3.711 A (center-to-center
˚
separation: 4.090 A). In addition, anionic building unit
2
ꢁ
[
Hg I ]
are packed between successive the cationic
2
6
NHC metallacrown ethers, and held together the cations
via weak Hgꢀ ꢀ ꢀI interactions, which extends the above
˚
1
D chains into 2D supramolecular layers. Thus aromatic
Agꢀ ꢀ ꢀO contacts are 2.885(4) and 3.678(5) A, showing that
p–p stacking interactions from benzimidazole rings, and
Hgꢀ ꢀ ꢀI interactions from cationic mercurys and anionic
iodides are mainly responsible for forming 2D supramolec-
ular layers in 1.
Agꢀ ꢀ ꢀO interactions can be neglected. In the crystal pack-
ing of complex 3, the 1D infinite chains are also formed
by the head-to-tail p–p stacking interactions from inter-
molecular benzimidazole rings, with the inter-planar sepa-
˚
˚
Compared with 1, complex 2 contains also a macrocy-
cle NHC metallacrown ether formed by a didentate che-
late bis(carbene) ligand with a long flexible linkage and
a mercury(II) (Fig. 3). The both benzimidazole rings
within each molecule form a dihedral angle of 70.8ꢁ.
Two ethyl chains point to same direction, and the mole-
cule possesses a cis-configuration. The coordinated envi-
ronment of mercury atom has some different from the
one in 1. In 2 each mercury atom is coordinated by two
carbene–carbons and two iodine atoms to form a distorted
tetrahedron arrangement. The C(9B)–Hg(1B)–C(22B) is
approximately linear with bond angle of 147.3(3)ꢁ, and
this value is obviously smaller than 175.9(4)ꢁ in 1. The
ration of 3.302 A (center-to-center separation: 4.705 A).
2.3. Thermogravimetric analysis of complexes 1, 2 and 3
Complexes 1, 2 and 3 are air stable at ambient condi-
tions and the thermogravimetric experiments were per-
formed to explore their thermal stabilities. The TGA
curve of 1 reveals that the complex starts to decompose
beyond 175 ꢁC with two steps of weight losses (peaks at
251.4 ꢁC and 366.8 ꢁC) and does not stop until heating ends
at 700 ꢁC. The TGA curve of 2 suggests that the first weight
loss of 8.90% in the region of 185–232 ꢁC (peaking at
225 ꢁC) corresponds to the expulsion of the lattice dichlo-
romethane molecules (calculated: 8.98%). The starting
decomposition of the residuary section occurs at 240 ꢁC
with two steps of weight losses (peaks at 259.1 ꢁC and
366.2 ꢁC) and does not stop until heating ends at 700 ꢁC.
The TGA curve of 3 reveals that the complex starts to
decompose beyond 240 ꢁC with two steps of weight losses
(peaks at 256.4 ꢁC and 333.9 ꢁC) and does not stop until
heating ends at 700 ꢁC.
˚
average Hg–C bond distances of 2.137 A are slightly
˚
longer than those of 2.075 A in 1 due to the variation of
coordination environment. The I(1B)–Hg(1B)–I(2B) bond
angle is 97.9(1)ꢁ, and the Hg(1B)–I(1B) and Hg(1B)–I(2B)
˚
˚
bond distances are 2.939(6) A and 3.141(6) A, respectively,
2
ꢁ
comparable to the values of [Hg I ] in 1. The internal
2
6
ring angle (N(1B)–C(9B)–N(2B)) at the carbene center is
07.3(6)ꢁ, which is somewhat smaller than that of corre-
1

Q.-X. Liu et al. / Journal of Organometallic Chemistry 692 (2007) 5671–5679
5675
Fig. 3. Intermolecular Iꢀ ꢀ ꢀH–C hydrogen bonds in 2. The unrelated hydrogen atoms have been omitted for clarity.
Fig. 4. Perspective view of 3 and anisotropic displacement parameters depicting 30% probability. Hydrogen atoms have been omitted for clarity.
3
. Conclusion
ies on new organometallic compounds from precursors and
analogous ligands are underway.
In summary, carbene precursors and their three new
flexible bidentate NHCs bridged mercury(II) and silver(I)
macrocyclic complexes have been synthesized and charac-
4. Experimental
2
terized. In packing diagrams of H L Æ I , 1, 2 and 3 benz-
4.1. General procedures
2
2
imidazole ring head-to-tail p–p stacking interactions are
2
observed. In packing diagrams of H L Æ I and 1 there
1,2-Bis(2-iodoethoxy)ethane was prepared according to
the literature methods [13]. All manipulations were per-
formed using Schlenk techniques, and solvents were puri-
fied by standard procedures. All the reagents for
syntheses and analyses were of analytical grade and used
without further purification. Melting points were deter-
2
2
exist intermolecular Iꢀ ꢀ ꢀH–C hydrogen bonds. These weak
interactions are helpful to forming 2D supramolecular lay-
ers or 3D supramolecular architecture. Complex 3 is stable
toward light and air in the solid state at room temperature,
which may offer convenient carbene precursor for the prep-
aration of other transition metal complexes. Further stud-
1
13
1
mined with a Boetius Block apparatus. H and C{ H}

5
676
Q.-X. Liu et al. / Journal of Organometallic Chemistry 692 (2007) 5671–5679
1
NMR spectra were recorded on a Varian Mercury Vx 300
spectrometer at 300 MHz and 75 MHz, respectively.
Chemical shifts, d, are reported in ppm relative to the inter-
nal standard TMS for both H and C NMR. J values are
given in Hz. Elemental analyses were measured using a Per-
kin–Elmer 2400C Elemental Analyzer.
4.4. Preparation of H L Æ (PF )
2
6 2
NH PF (2.720 g, 16.8 mmol) was added to a methanol
solution of H L Æ I (3.000 g, 4.2 mmol) whilst stirring and
2 2
4
6
1
13
1
a white precipitate formed immediately. The product was
collected by filtration, washed with small portions of cold
methanol, and dried in vacuum to give 2.820 g of
1
1
4
.2. Preparation of H L Æ I
H L Æ (PF ) . Yield: 89.5%. M.p.: 140–142 ꢁC. Anal. Calcd
2
2
2
6 2
for C H F N O P : C, 44.57; H, 5.34; N, 7.43. Found:
2
8
40 12
4
2 2
1
A THF solution of benzimidazole (1.000 g, 8.5 mmol)
was added to a suspension of oil-free sodium hydride
0.244 g, 10.2 mmol) in THF (25 mL) and stirred for 1 h
at 60 ꢁC. Then THF (20 mL) solution of sec-butyl bromide
1.276 g, 9.3 mmol) was dropwise added to above solution.
C, 44.64; H, 5.55; N, 7.31%. H NMR (300 MHz, CDCl ):
3
d 0.92 (t, J = 5.4, 6H, CH ), 1.78 (d, J = 5.0, 6H, CH ),
3
3
(
2.18 (m, 4H, CH ), 4.15 (m, 2H, CH), 4.50 (t, J = 4.0,
2
4H, CH ), 4.77 (t, J = 4.0, 4H, CH ), 5.26 (t, J = 4.0,
2
2
(
4H, CH ), 7.70 (m, 6H, PhH), 7.95 (t, J = 6.5, 2H, PhH),
2
11.40 (s, 2H, 2-benzimiH) (benzimi = benzimidazole).
1
3
The mixture was continued to stir for 48 h at 60 ꢁC and a
yellow solution was obtained. The solvent was removed
C
NMR (75 MHZ, DMSO-d ): d 138.8 (NCHN), 137.2,
6
with a rotary evaporator and H O (30 mL) was added to
120.8 and 113.9 (PhC), 69.4 and 68.3 (OCH ), 55.1 and
2
2
the residue. Then the solution was extracted with CH Cl
53.2 (NCH ), 28.8 (CCH ), 17.6 (CCH ), 9.3 (CCH ).
2
2
2
2
3
3
(
3 · 20 mL), and the extracting solution was dried with
1
anhydrous MgSO . After removing CH Cl , a pale yellow
liquid 1- butylbenzimidazole was obtained. Yield: 1.360 g
4.5. Preparation of HgL Æ (Hg I ) (1)
2 6
4
2
2
sec
t
(
92%).
A
A suspension of KOBu (0.090 g, 0.8 mmol), precursor
H L Æ I (0.200 g, 0.28 mmol) and mercury(II) iodide
sec
solution of 1- butylbenzimidazole (1.550 g,
1
2
2
8
4
.9 mmol) and 1,2-dis(2-iodoethoxy)ethane (1.500 g,
.1 mmol) in THF (50 mL) was stirred for three days under
(0.409 g, 0.90 mmol) in THF (20 mL) and acetonitrile
(20 mL) was refluxed for 24 h. A brown solution was
formed and the solvent was removed with a rotary evapo-
rator. The water (30 mL) was added to the residue and the
solution extracted with CH Cl (3 · 20 mL). The extracting
reflux, and a pale yellow precipitate was formed. The prod-
uct was filtred and washed with THF. The pale yellow
powder of bis-benzimidazolium iodide (H L Æ I ) are
obtained by recrystallization from methanol/diethyl ether.
Yield: 2.290 g (78.6%). M.p.: 156–158 ꢁC. Anal. Calc. for
C H I N O : C, 46.81; H, 5.61; N, 7.80. Found: C,
1
2
2
2
2
solution was dried with anhydrate MgSO , then the solu-
4
tion was concentrated to 10 ml and hexane (2 mL) was
added, as a result a pale yellow powder was obtained.
Yield: 0.180 g (35.4%). M.p.: 220–222 ꢁC. Anal. Calc. for
C H Hg I O N : C, 18.42; H, 2.10; N, 3.07. Found: C,
2
8
40 2
4
2
1
4
0
2
4
4
1
6.76; H, 5.48; N, 7.66%. H NMR (300 MHz, CDCl ): d
.97 (t, J = 5.4, 6H, CH ), 1.79 (d, J = 5.1, 6H, CH ),
.14 (m, 4H, CH ), 4.15 (m, 2H, CH), 4.53 (t, J = 4.0,
3
3
3
28 38
3 6
2
4
1
18.65; H, 2.43; N, 3.21%. H NMR (300 MHz, CDCl ): d
2
3
H, CH ), 4.72 (t, J = 4.0, 4H, CH ), 5.20 (t, J = 4.0,
0.94 (t, J = 5.4, 6 H, CH ), 1.71 (d, J = 5.2, 6H, CH ),
2
2
3
3
H, CH ), 7.71 (m, 6H, PhH), 7.94 (t, J = 6.4, 2H, PhH),
2.16 (m, 4H, CH ), 4.23 (m, 2H, CH), 4.56 (t, J = 4.0,
2
2
1
3
1.43 (s, 2H, 2-benzimiH) (benzimi = benzimidazole).
C
4H, CH ), 4.75 (t, J = 4.0, 4H, CH ), 5.23 (t, J = 4.0,
2
2
NMR (75 MHz, DMSO-d ): d 138.2 (NCHN), 136.4,
4H, CH ), 7.77 (m, 6H, PhH), 7.95 (t, J = 6.2, 2H, PhH).
6
2
1
21.3 and 116.2 (PhC), 70.1 and 68.8 (OCH ), 54.7 and
2
5
3.5 (NCH ), 29.6 (CCH ), 17.9 (CCH ), 10.3 (CCH ).
2
2
3
3
Table 1
˚
2
Selected bond lengths (A) angles (ꢁ) for H
2
L Æ I
2
and 1
2
4
.3. Preparation of H L Æ I
2
2
2
H
2
L Æ I
2
1
2
O(1)–C(1)
O(1)–C(2)
N(1)–C(3)
N(1)–C(4)
N(1)–C(12)
N(2)–C(9)
N(2)–C(10)
N(2)–C(12)
1.431(6)
1.413(6)
1.468(5)
1.390(5)
1.321(5)
1.387(6)
1.481(6)
1.321(6)
Hg(1A)
Hg(1A)
Hg(2A)
Hg(2A)
Hg(2A)
Hg(2A)
O(1A)
2.072(11)
2.078(12)
2.6744(14)
2.6948(13)
2.8652(12)
3.0922(12)
1.391(16)
1.390(19)
The H L Æ I was prepared in a manner analogous to
2
2
1
that for H L Æ I , only with ethyl bromide instead of sec-
butyl bromide. Compound H L Æ I was obtained as a pale
yellow powder. Yield: 2.060 g (76.6%). M.p.: 192–194 ꢁC.
Anal. Calc. for C H I N O : C, 43.52; H, 4.87; N, 8.46.
Found: C, 43.34; H, 4.56; N, 8.72%. H NMR (300 MHz,
DMSO-d ): d 1.62 (t, J = 5.5, 6H, CH ), 3.36 (t, J = 4.2,
H, CH ), 3.78 (t, J = 4.2, 4H, CH ), 4.72 (t, J = 4.2,
2 2
H, CH ), 4.86 (q, J = 5.5, 4H, CH ), 7.68 (m, 4H,
PhH), 7.90 (d, J = 6.3, 2H, PhH), 7.97 (d, J = 6.3, 2H,
PhH), 11.50 (s, 2H, 2-benzimiH) (benzimi = benzimid-
azole). C NMR (75 MHz, DMSO-d ): d 139.8 (NCHN),
36.2, 123.3 and 114.8 (PhC), 69.1 and 68.4 (OCH ), 52.8
2
2
2
2
2
2
2
4
32 2
4
2
1
O(1A)
6
3
N(1)–C(12)–N(2)
C(1)–O(1)–C(2)
C(3)–N(1)–C(4)
C(3)–N(1)–C(12)
C(4)–N(1)–C(12)
C(9)–N(2)–C(12)
C(10)–N(2)–C(12)
C(9)–N(2)–C(10)
110.8(4)
N(1A)
C(11A)
N(1A)
I(1A)
I(1A)
I(2A)
1.352(14)
175.9(4)
4
4
111.8(4)
123.9(3)
128.1(4)
107.9(4)
108.2(4)
124.1(4)
127.6(4)
2
2
108.7(10)
122.96(4)
119.32(4)
106.87(4)
116.3(12)
114.9(12)
1
3
6
C(13A)
C(15A)
1
and 46.2 (NCH ), 12.8 (CCH ).
2
3

Q.-X. Liu et al. / Journal of Organometallic Chemistry 692 (2007) 5671–5679
5677
1
3
2
C NMR (75 MHZ, DMSO-d ): d 175.0 (Ccarbene), 128.2,
matrix least squares on F using the SHELXTL package [16].
6
1
17.4 and 113.8 (PhC), 69.8 (OCH ), 53.2 (NCH ), 47.8
All hydrogen atoms were generated geometrically (C–H
bond lengths fixed at 0.96 A), assigned appropriated isotro-
2
2
˚
(
NCH), 28.2 (CCH C), 19.1 (CCH ), 9.1 (CCH ).
2
3
3
pic thermal parameters and included in structure factor cal-
culations. Selected bond lengths and angles were showed in
2
4
.6. Preparation of HgL Æ I
2
t
A suspension of KOBu (0.090 g, 0.8 mmol), precursor
2
Table 2
H L Æ I (0.200 g, 0.3 mmol) and anhydrous mercury(II)
2
2
˚
Selected bond lengths (A) angles (ꢁ) for 2 and 3
acetate (0.106 g, 0.3 mmol) in THF (20 mL) and acetonitrile
20 mL) was refluxed for 24 h. A brown solution was formed
2
3
(
and the solvent was removed with a rotary evaporator. The
water (30 mL) was added to the residue and the solution
extracted with CH Cl (3 · 20 mL). The extracting solution
Hg(1)–C(9)
Hg(1)–C(22)
Hg(1)–I(1)
Hg(1)–I(2)
N(1)–C(2)
N(1)–C(3)
N(1)–C(9)
N(2)–C(8)
N(2)–C(9)
N(2)–C(10)
2.148(7)
2.127(7)
2.9392(6)
3.1413(6)
1.473(9)
1.406(9)
1.351(9)
1.390(9)
1.351(9)
1.483(10)
Ag(1)–C(11)
Ag(1)–C(18)
N(1)–C(10)
N(1)–C(11)
N(1)–C(12)
N(2)–C(3)
N(2)–C(5)
N(2)–C(11)
C(11)–Ag(1)–C(18)
N(1)–C(11)–N(2)
2.088(6)
2.090(6)
1.368(7)
1.373(7)
1.459(7)
1.482(8)
1.399(8)
1.342(7)
2
2
was dried with anhydrate MgSO , then the solution was con-
4
centrated to 10 mL and hexane (5 mL) was added, as a result
a pale yellow powder was obtained. Yield: 0.980 g (37.7%).
M.p.: 262–264 ꢁC. Anal. Calc. for C H HgI N O : C,
2
4
30
2
4
2
174.0(2)
105.8(5)
3
6
6
3.48; H, 3.51; N, 6.51. Found: C, 33.56; H, 3.73; N,
1
.33%. H NMR (300 MHz, DMSO-d ): d 1.64 (t, J = 5.6,
6
N(1)–C(9)–N(2)
C(9)–Hg(1)–C(22)
C(9)–Hg(1)–I(1)
C(9)–Hg(1)–I(2)
C(22)–Hg(1)–I(1)
C(22)–Hg(1)–I(2)
I(1)–Hg(1)–I(2)
107.3(6)
147.3(3)
C(10)–N(1)–C(11)
C(10)–N(1)–C(12)
C(11)–N(1)–C(12)
C(3)–N(2)–C(5)
C(3)–N(2)–C(11)
C(5)–N(2)–C(11)
110.7(5)
125.8(5)
123.5(5)
126.9(5)
122.8(6)
110.3(5)
H, CH ), 3.40 (t, J = 4.2, 4H, CH ), 3.79 (t, J = 4.2, 4H,
3
2
CH ), 4,76 (t, J = 4.2, 4H, CH ), 4.80 (q, J = 5.6, 4H,
2
2
96.52(17)
103.40(19)
111.3(2)
89.89(19)
97.911(17)
CH ), 7.68 (m, 4H, PhH), 7.92 (d, J = 6.3, 2H, PhH), 7.98
2
1
3
(
(
(
d, J = 6.3, PhH). C NMR (75 MHz, DMSO-d ): d 173.0
6
Ccarbene), 127.9, 116.0 and 113.4 (PhC), 70.1 and 69.3
OCH ), 53.4 (NCH ), 46.2 (NCH ), 13.4 (CCH ).
2
2
2
3
1
Table 3
4
.7. Preparation of AgL Æ PF
6
2
Summary of crystallographic data for H
2
L Æ I
2
and 1
2
H
2
L Æ I
2
1
Silver oxide (0.031 g, 0.14 mmol) was added to a solu-
1
Chemical formula
C
662.34
24
H
32 Æ I
2
N
4
O
2
C
28 3 6 4 2
H38Hg I N O
tion of compound H L Æ (PF ) (0.200 g, 0.27 mmol) in
2
6 2
F
w
1825.79
Triclinic
dichloromethane (30 mL) and the suspension solution
was stirred for 24 h at refluxing. The resulting solution
Crystal system
Space group
Monoclinic
P2(1)/c
6.8232(17)
12.545(3)
15.976(4)
90
100.181(4)
90
1345.9(6)
2
1.634
2.363
652
0.24 · 0.20 · 0.16
2.08, 25.03
293(2)
6641
2363
ꢀ
P1
was filtered and concentrated to 10 mL, and Et O (5 mL)
˚
2
a (A)
10.8243(13)
12.1816(14)
16.3255(19)
93.155(2)
96.977(2)
97.284(2)
2114.0(4)
2
2.868
15.276
1616
0.24 · 0.22 · 0.20
1.69, 25.03
293(2)
10862
7421
˚
was added to precipitate a white powder. Isolation by fil-
b (A)
1
˚
c (A)
tration yields AgL Æ PF . Yield: 0.098 g (43.8%). M.p.:
6
a (ꢁ)
b (ꢁ)
c (ꢁ)
1
60–162 ꢁC. Anal. Calc. for C H F AgN O P: C, 47.01;
2
8
38
6
4
2
1
H, 5.35; N, 7.83. Found: C, 47.23; H, 5.44; N, 7.79%. H
˚
3
NMR (300 MHz, CDCl ): d 0.91 (t, J = 5.2, 6H, CH ),
3
3
V (A )
1
2
.74 (d, J = 5.0, 6H, CH ), 2.12 (m, 4H, CH ), 4.20 (m,
Z
3
2
3
D
calc (Mg/m )
H, CH), 4.55 (t, J = 3.8, 4H, CH ), 4.77 (t, J = 3.8, 4H,
2
ꢁ1
Absorption coefficient (mm
F(000)
Crystal size (mm)
hmin, hmax, deg
T (K)
)
CH ), 5.26 (t, J = 3.8, 4H, CH ), 7.73 (m, 6H, PhH), 7.92
2
2
1
3
(
1
(
(
t, J = 6.4, 2H, PhH). C NMR (75 MHz, DMSO-d ): d
6
27.8, 118.0 and 114.5 (PhC), 69.6 and 69.3 (OCH ), 55.3
2
NCH ), 54.8 (NCH), 28.8 (CCH C), 18.7 (CCH ), 9.0
2
2
3
Number of data collected
Number of unique data
CCH ). The carbene carbon was not observed.
3
Number of refined parameters
Goodness-of-fit on F
146
1.071
387
1.034
4
.8. X-ray structure determinations
2a
b
2
Final R indices [I > 2r(I)]
For compounds H L Æ I , 1, 2 and 3, selected single crys-
2
2
R
1
0.0414
0.0963
0.0474
0.1184
tals were mounted on a Bruker APEX II CCD diffractometer
at 293(2) K with Mo Ka radiation (k = 0.71073 A) by x scan
wR
2
˚
R indices (all data)
mode. Data collection and reduction were performed using
the SMART and SAINT software [14] with frames of 0.6ꢁ oscilla-
tion in the h range 1.8 < h < 25ꢁ. An empirical absorption
correction was applied using the SADABS program [15]. The
structures were solved by direct methods and all non-hydro-
gen atoms were subjected to anisotropic refinement by full-
R
1
0.0469
0.0999
1/2
0.0713
0.1335
wR
2
P
a
2
o
2
2
Goof = [ x(F ꢁ F ) /(n ꢁ p)] , where n is the number of reflection
c
and p is the number of parameters refined.
b
P
P
2
2
o
R = (jjF j ꢁ jF jj)/ jF j; wR = 1/[r (F ) + (0.0691P) + 1.4100P],
1
o
c
o
2
2
o
2
c
where P ¼ ðF þ 2F Þ=3.

5678
Q.-X. Liu et al. / Journal of Organometallic Chemistry 692 (2007) 5671–5679
Table 4
References
Summary of crystallographic data for 2 and 3
2
3
[1] A.J. Arduengo III, R.L. Harlow, M. Kline, J. Am. Chem. Soc. 113
1991) 361.
(
Chemical formula
C
945.84
Triclinic
P1
8.8646(5)
8.9060(5)
20.1169(11)
88.1020(10)
81.4130(10)
77.8530(10)
1535.23(15)
2
24
H30HgI
2
N
O
4 2
Æ CH
2
Cl
2
C
715.46
28 6 4 2
H38AgF N O P
[2] (a) J.C. Green, R.G. Scurr, P.L. Arnold, F.G.N. Cloke, Chem.
F
w
Commun. (1997) 1963;
Crystal system
Space group
Monoclinic
P2(1)/c
10.3238(6)
18.9279(10)
16.2906(9)
90
97.3370(10)
90
3157.2(3)
4
(
b) L.J. Xu, W.P. Chen, J.F. Bickley, A. Steiner, J.L. Xiao, J.
Organomet. Chem. 598 (2000) 409;
c) A.A. Danopoulos, N. Tsoureas, S.A. Macgregor, C. Smith,
Organometallics 26 (2007) 253;
ꢀ
˚
a (A)
(
˚
b (A)
˚
c (A)
(
(
(
d) M. Regitz, Angew. Chem., Int. Ed. Engl. 35 (1996) 725;
e) W.A. Herrmann, C. K o¨ cher, Angew. Chem., Int. Ed. Engl. 41
2002) 1290;
a (ꢁ)
b (ꢁ)
c (ꢁ)
˚
3
(f) N. Saino, D. Kogure, S. Okamoto, Org. Lett. 7 (2005) 3065;
g) C. Fischer, S.W. Smith, D.A. Powell, G.C. Fu, J. Am. Chem.
Soc. 128 (2006) 1472;
h) D. Enders, H. Gielen, G. Raabe, J. Runsink, J.H. Teles, Chem.
Ber. 129 (1996) 1483;
i) M.J. Green, K.J. Cavell, B.W. Skelton, A.H. White, J. Organomet.
V (A )
(
Z
3
D
calc (Mg/m )
2.046
1.505
0.756
(
Absorption coefficient 7.226
ꢁ1
(
mm
F(000)
Crystal size (mm)
)
(
1690
1464
Chem. 554 (1998) 175.
0.24 · 0.22 · 0.16
1.02, 25.03
293(2)
0.24 · 0.22 · 0.18
1.66, 25.03
293(2)
[3] (a) J.C.C. Chen, I.J.B. Lin, J. Chem. Soc., Dalton Trans. (2000) 839;
h
min, hmax (ꢁ)
(
1
(
7
b) J. Huang, E.D. Stevens, S.P. Nolan, Organometallics 19 (2000)
194;
c) C. Bolm, M. Kesselgruber, G. Raabe, Organometallics 21 (2002)
07;
d) R.E. Douthwaite, M.L.H. Green, P.J. Silcock, P.T. Gomes, J.
Chem. Soc., Dalton Trans. (2002) 1386;
e) D.J. Nielsen, K.J. Cavell, B.W. Skelton, A.H. White, Inorg.
Chim. Acta 327 (2002) 116;
f) A.J. Arduengo III, M. Tamm, J.C. Calabrese, J. Am. Chem. Soc.
T (K)
Number of data
collected
Number of unique
data
Number of refined
parameters
Goodness-of-fit on F
7979
15971
5426
327
5581
383
(
(
2
a
1.064
1.078
(
b
Final R indices [I > 2r(I)]
116 (1994) 3625;
R
wR
1
0.0351
0.0874
0.0530
0.1381
(g) A.J. Arduengo III, M. Kline, J.C. Calabrese, F. Davidson, J. Am.
Chem. Soc. 113 (1991) 9704;
2
(
(
h) N. Kuhn, T. Kratz, G. Henkel, Chem. Commun. (1993) 1778;
i) A.J. Arduengo III, F. Davidson, H.V.R. Dias, J.R. Goerlich, D.
R indices (all data)
R
wR
1
0.0443
0.0990
0.0900
0.1582
Khasnis, W.J. Marshall, T.K. Prakasha, J. Am. Chem. Soc. 119
1997) 12742;
2
(
P
a
2
2
2
1/2
Goof = [ x(F ꢁ F ) /(n ꢁ p)] , where n is the number of reflection
(j) D. Bourissou, O. Guerret, F.P. Gabbai, G. Bertrand, Chem. Rev.
100 (2000) 39;
(k) M. Alcarazo, S.J. Roseblade, A.R. Cowley, R. Fernandez, J.M.
Brown, J.M. Lassaletta, J. Am. Chem. Soc. 127 (2005) 3290;
o
c
and p is the number of parameters refined.
b
P
P
2
2
o
R
1
=
(jjF
o
j ꢁ jF
c
jj)/ jF
o
j; wR
2
= 1/[r (F ) + (0.0691P) + 1.4100P],
2
o
2
c
where P ¼ ðF þ 2F Þ=3.
(
l) L. Ackermann, A. F u¨ rstner, T. Weskamp, F.J. Kohl, W.A.
Herrmann, Tetrahedron Lett. 40 (1999) 4787;
(
(
(
(
m) J.C. Garrison, W.J. Youngs, Chem. Rev. 105 (2005) 3978;
n) W.A. Herrmann, C. K o¨ cher, Angew. Chem., Int. Ed. Engl. 96
1997) 2162;
Tables 1 and 2, and crystallographic data were summarised
2
in Tables 3 and 4 for H L Æ I , 1, 2 and 3.
2
2
o) F.M. Rivas, U. Riaz, A. Giessert, J.A. Smulik, S.T. Diver, Org.
Lett. 3 (2001) 2673;
Acknowledgements
(p) F.E. Hahn, M.C. Jahnke, T. Pape, Organometallics 26 (2007)
1
(
50;
q) D. Enders, K. Breuer, G. Raabe, J. Runsink, J.H. Teles, J.-P.
Melder, K. Ebel, S. Brode, Angew. Chem., Int. Ed. Engl. 34 (1995)
84.
This work was financially supported by the National
Science Foundation of China (Project Grant No.
2
2
0672081) and the Natural Science Foundation of Tianjin
[4] (a) U. Scheele, S. Dechert, F. Meyer, Inorg. Chim. Acta 359 (2006) 4891;
(
07JCYBJC00300).
(b)X.J. Wan,F.B. Xu,Q.S. Li, H.B. Song,Z.Z. Zhang, Organometallics
2
4 (2005) 6066;
c) J.C. Garrisen, R.S. Simons, J.M. Talley, C. Wesdemiotis, C.A.
Tessier, W.J. Youngs, Organometallics 20 (2001) 1276;
d) A. Caballero, E. D ´ı ez-Barra, F.A. Jal o´ n, S. Merino, J. Tejeda, J.
(
Appendix A. Supplementary material
(
CCDC 657127, 657128, 657129 and 657130 contain the
Organomet. Chem. 617–618 (2001) 395;
(e) B. Bildstein, M. Malaun, H. Kopacka, K.H. Ongania, K. Wurst, J.
Organomet. Chem. 552 (1998) 45;
2
supplementary crystallographic data for H L Æ I , 1, 2 and
2
2
3
. These data can be obtained free of charge from The
(
(
f) I.J.B. Lin, C.S. Vasam, Coord. Chem. Rev. 251 (2007) 642;
g)D.J. Nielsen, K.J. Cavell, B.W. Sketon, A.H. White, Organometallics
Cambridge Crystallographic Data Centre via www.ccdc.
cam.ac.uk/data_request/cif. Supplementary data associ-
ated with this article can be found, in the online version,
at doi:10.1016/j.jorganchem.2007.09.027.
2
(
5 (2006) 4850;
h) J.W. Wang, H.B. Song, Q.S. Li, F.B. Xu, Z.Z. Zhang, Inorg. Chim.
Acta 358 (2005) 3653;

Q.-X. Liu et al. / Journal of Organometallic Chemistry 692 (2007) 5671–5679
5679
(
i) D.J. Nielsen, K.J. Cavell, B.W. Sketon, A.H. White, Inorg. Chim.
Acta 352 (2003) 143;
j) J.W. Wang, Q.S. Li, F.B. Xu, H.B. Song, Z.Z. Zhang, Eur. J. Org.
Chem. (2006) 1310;
(g) J.J. Song, F. Gallou, J.T. Reeves, Z. Tan, N.K. Yee, C.H.
Senanayake, J. Org. Chem. 71 (1991) 1273;
(h) E. Despagnet-Ayoub, R.H. Grubbs, Organometallics 24 (2005)
338;
(
(
(
(
k) K.M. Lee, J.C.C. Chen, I.J.B. Lin, J. Organomet. Chem. 617–618
2001) 364;
l) M.K. Samantaray, V. Katiyar, K. Pang, H. Nanavati, P. Ghosh, J.
(i) J. Ruiz, G. Garcia, M.E.G. Mosquera, B.F. Perandones, M.P.
Gonzalo, M. Vivanco, J. Am. Chem. Soc. 127 (2005) 8584;
(j) N. Hadei, E.A.B. Kantchev, C.J. Brien, M.G. Organ, Org. Lett. 7
(2005) 1991;
(k) D.S. McGuinness, K.J. Cavell, B.W. Skekton, A.H. White,
Organometallics 18 (1999) 1596.
Organomet. Chem. 692 (2007) 1672;
m) Q.X. Liu, L.N. Yin, J.C. Feng, J. Organomet. Chem. 692 (2007)
655;
n) O. Guerret, S. Sole, H. Gornitzka, M.L. Teichert, G. Teingnier, G.
Berte, J. Am. Chem. Soc. 119 (1997) 6668;
o) R.Z. Ku, J.C. Huang, J.Y. Cho, F.M. Kiang, K.R. Reddy, Y.C.
(
3
(
[8] (a) M. Hasan, I.V. Kozhevnikov, M.R.H. Siddiqui, C. Femoni, A.
Steiner, N. Winterton, Inorg. Chem. 40 (2001) 795;
(b) J.A. Loch, M. Albrecht, E. Peris, J. Mata, J.W. Faller, R.H.
Crabtree, Organometallics 21 (2002) 700;
(
Chen, K.J. Lee, J.H. Lee, G.H. Lee, S.M. Peng, S.T. Liu, Organome-
tallics 18 (1999) 2145;
(c) S. Grundemann, M. Albrecht, A. Kovacevic, J.W. Faller, R.H.
Crabtree, J. Chem. Soc., Dalton Trans. (2002) 2163;
(d) W.A. Herrmann, L.J. Goossen, M. Spiegler, Organometallics 17
(1998) 2162;
(
p) Q.X. Liu, F.B. Xu, Q.S. Li, X.S. Zeng, X.B. Leng, Y.L. Chou, Z.Z.
Zhang, Organometallics 22 (2003) 309;
q) A.M. Magill, D.S. Mcguinness, K.J. Cavell, G.J.P. Britovsek, V.C.
(
Gibson, A.J.P. White, D.J. Williams, A.H. White, B.W. Skekton, J.
Organomet. Chem. 617–618 (2001) 546;
(e) K.E. Krahulic, G.D. Enright, M. Parvez, R. Roesler, J. Am.
Chem. Soc. 127 (1991) 4142;
(
1
r) C.K. Lee, K.M. Lee, K.M. Lin, J.B. Ivan, Organometallics 21 (2002)
0.
(f) L. Xu, W. Chen, J. Xiao, Organometallics 19 (2000) 1123.
[9] (a) P.J. Barnard, M.V. Baker, S.J. Berners-Price, B.W. Sketlon, A.H.
White, J. Chem. Soc., Dalton Trans. (2004) 1038;
(b) F. Mohr, R.J. Puddephatt, J. Organomet. Chem. 689 (2004) 374;
(c) J.M. Butler, M.J. Jablonsky, G.M. Gray, Organometallics 22
(2003) 1081;
[
[
5] (a) A.K. Nebioglu, M.J. Panzner, C.A. Tessier, C.L. Cannon, W.J.
Youngs, Coord. Chem. Rev. 251 (2007) 884;
(
b) A. Melaiye, Z. Sun, K. Hindi, A. Milsted, D. Ely, D.H. Reneker,
C.A. Tessier, W.J. Youngs, J. Am. Chem. Soc. 127 (2005) 2285;
c) A. Melaiye, R.S. Simons, A. Milsted, F. Pingitore, C. Wesdemi-
(
(d) G.M. Gray, C.H. Duffey, Organometallics 13 (1994) 1542;
(e) G.M. Gray, C.H. Duffey, Organometallics 14 (1995) 245;
(f) G.M. Gray, A. Varshney, C.H. Duffey, Organometallics 14 (1995)
238;
otis, C.A. Tessier, W.J. Youngs, J. Med. Chem. 47 (2004) 973.
6] (a) H.M. Lee, P.L. Chiu, C.H. Hu, C.L. Lai, Y.C. Chou, J.
Organomet. Chem. 690 (2005) 403;
(
b) K.S. Coleman, H.T. Chamberlayne, S. Turberville, M.L.H.
Green, A.R. Cowley, Dalton Trans. (2003) 2917;
c) P.L. Arnold, A.C. Scarisbrick, A.J. Blake, C. Wilson, Chem.
Commun. (2002) 2340;
(g) P.J. Stang, D.H. Cao, K. Chen, G.M. Gray, D.C. Muddiman,
R.D. Smith, J. Am. Chem. Soc. 119 (1997) 5163;
(h) C.H. Duffey, C.H. Lake, G.M. Gray, Organometallics 17 (1998)
3550;
(
(
(
(
d) H.M.F. Wang, I.J.B. Lin, Organometallics 17 (1998) 972;
e) S. Liu, T. Hsieh, G. Lee, S. Peng, Organometallics 17 (1998) 993;
(i) M.J. Green, K.J. Cavell, P.G. Edwards, R.P. Tooze, B.W. Sketon,
A.H. White, J. Chem. Soc., Dalton Trans. (2004) 3251.
[10] (a) J.C. Garrison, W.J. Youngs, Chem. Rev. 105 (2005) 3978;
(b) X. Hu, I. Castro-Rodriguez, K. Olsen, K. Meyer, Organometallics
23 (2004) 755.
[11] (a) A.J. Black, G. Baum, N.R. Champness, S.S.M. Chung, P.A.
Cooke, D. Fenske, A.N. Khlobystov, D.A. Lemenovskki, W.S. Li,
M. Schroder, Dalton Trans. (2000) 4285;
¨
f) W.A. Herrmann, S.K. Schneider, K. Ofele, M. Sakamoto, E.
Herdtweck, J. Organomet. Chem. 689 (2004) 2441;
g) D.J. Nielsen, K.J. Cavell, B.W. Skelton, A.H. White, Inorg.
Chim. Acta 352 (2003) 143;
h) H.M. Lee, J.Y. Zeng, C.H. Hu, M.T. Lee, Inorg. Chem. 43 (2004)
822;
i) S. Winston, N. Stylianides, A.A.D. Tulloch, J.A. Wright, A.A.
Danopoulos, Polyhedron 23 (2004) 2813;
j) J.J. Van Veldhuizen, J.E. Campbell, R.E. Giudici, A.H. Hoveyda,
J. Am. Chem. Soc. 127 (2005) 6877;
k) P.L. Arnold, M. Rodden, K.M. Davis, A.C. Scarisbrick, A.J.
(
(
6
(
(b) C.A. Hunter, J.K.M. Sanders, J. Am. Chem. Soc. 112 (1990)
5525;
(c) C.A. Janiak, Dalton Trans. (2000) 3885;
(d) A.N. Khlobystov, A.J. Blake, N.R. Champness, D.A. Leme-
novskki, A.C. Majouga, N.V. Zyk, M. Schroder, Coord. Chem. Rev.
222 (2001) 155.
(
(
Blake, C. Wilson, Chem. Commun. (2004) 1612.
[
7] (a) J. Huang, S.P. Nolan, J. Am. Chem. Soc. 121 (1999) 9889;
[12] R.D. Rogers, A.H. Bond, J.L. Wolff, J. Coord. Chem. 29 (1993) 187.
[13] S. Kulstad, L.A. Malmsten, Tetrahedron Lett. 21 (1980) 643.
[14] SMART 5.0 and SAINT 4.0 for Windows NT, Area Detector Control and
Integration Software, Bruker Analytical X-Ray Systems, Inc., Mad-
ison, WI, USA, 1998.
(
b) M.G. Gardiner, W.A. Herrmann, C.-P. Reisinger, J. Schwarz,
M. Spiegler, J. Organomet. Chem. 572 (1999) 239;
c) L.H. Gade, S.B. Laponnaz, Coord. Chem. Rev. 251 (2007)
18;
(
7
(
(
d) W.J. Sommer, M. Weck, Coord. Chem. Rev. 251 (2007) 860;
e) S.K. Schneider, C.F. Rentzsch, A. Kr u¨ ger, H.G. Raubenheimer,
[15] G.M. Sheldrick, SADABS, Program for Empirical Absorption Correc-
tion of Area Detector Data, Univ. of G o¨ ttingen, Germany, 1996.
[16] G.M. Sheldrick, SHELXTL 5.10 for Windows NT, Structure Determi-
nation Software, Brucker Analytical X-Ray Systems, Inc., Madison,
WI, USA, 1997.
W.A. Herrmann, J. Mol. Cat. A: Chem. 265 (2007) 50;
f) M.A. Taige, A. Zeller, S. Ahrens, S. Goutal, E. Herdtweck, T.
Strassner, J. Organomet. Chem. 692 (2007) 1519;
(