Imidazoline-2-ylidene metal complexes with pendant ferrocenyl substituents

Article abstract of DOI:10.1016/S0022-328X(97)00464-6

Imidazolium and benzimidazolium salts with ferrocenylated alkyl side chains are prepared as progenitors of N-[(ferrocenyl)alkyl](benz)imidazoline-2-ylidene carbenes, which form metal complexes of W(0), Pd(II), and Hg(II). X-ray structures and other spectr

Full text of DOI:10.1016/S0022-328X(97)00464-6

Ž
.
Journal of Organometallic Chemistry 552 1998 45–61
Imidazoline-2-ylidene metal complexes with pendant ferrocenyl
substituents
a
a
b
Benno Bildstein a,1,), Michael Malaun , Holger Kopacka , Karl-Hans Ongania ,
a
Klaus Wurst
a
Institut fur Allgemeine, Anorganische, und Theoretische Chemie, UniÕersitat Innsbruck, Innrain 52a, Innsbruck A-6020, Austria
¨
¨
b
Institut fur Organische Chemie, UniÕersitat Innsbruck, Innrain 52a, Innsbruck A-6020, Austria
¨
¨
Received 4 June 1997
Abstract
Imidazolium and benzimidazolium salts with ferrocenylated alkyl side chains are prepared as progenitors of N-
xŽ Ž . Ž . Ž .
wŽ
.
.
ferrocenyl alkyl benz imidazoline-2-ylidene carbenes, which form metal complexes of W 0 , Pd II , and Hg II . X-ray structures and
other spectroscopic properties show that these carbene precursors and complexes are analogous to published non-ferrocenylated
complexes with regard to the coordination sphere at the metal, but different in terms of steric protection of the central metal by the bulky
ferrocenyl substituents and in terms of distinguishable redox potentials of the ferrocenerferrocenium couple. q 1998 Elsevier Science
S.A.
Keywords: Carbene; Ferrocene; Iron; Tungsten; Palladium; Mercury; X-ray structure
1. Introduction
The nucleophilicity of these imidazoline-2-ylidenes
w
is now well documented 10,8,9,11,14,12,13,15–
x
It is now well established that carbenes exist not only
as unstable reactive intermediates, but can also be iso-
lated in pure form, if the carbene carbon is part of a
heterocyclic ring andror substituted by two electron-
23,27,24–26,28–34,37,35,36,38–44 , resulting in stable
Lewis acid–base complexes with electrophiles from
almost all groups of the periodic table. From an applica-
tion-oriented point of view, the high stability of such
metal carbene complexes and their compatibility with
various oxidation states of the metal is of practical
interest in the design of new transition metal catalysts
w
x
donating moieties 1–6 . Since the first report on a
stable and crystalline imidazoline-2-ylidene by Ar-
w x
duengo et al. 7 , based on chemistry developed earlier
w
x
w
x
w
by Wanzlick 8,9 , Wanzlick and Schikora 10 , Wan-
for Heck coupling reactions and hydrosilylations 20–
w
x
x
zlick and Schonherr 11–13 and, Schonherr and Wan-
23,27,24–26,34 . Furthermore, the free carbenes them-
¨
¨
w
x
zlick 14 , the chemical properties of these nucleophilic
carbenes have been investigated within the recent years
selves are very active catalysts for benzoin-type C–C-
w
x
coupling reactions 9,11,33,37 .
Recent work by Herrmann et al. 20–26 , Ofele et al.
¨
x
w
x
w
x
w
by Arduengo et al. 15–19 , Herrmann et al. 20–26 ,
¨
w
x
w
x
w
x w x
27 , Enders et al. 33–36 and Teles et al. 37 shows
w x
Ofele et al. 27 , Kuhn et al. 28–32 , Enders et al.
w
x
w
x
w
x
33–36 , Teles et al. 37 and others 38–44 . In addi-
tion, a number of theoretical studies concerning the
the significance of steric and electronic effects of the
1,3-substituents of the imidazoline-2-ylidenes with re-
spect to their catalytic activity and selectivity. Whereas
up to now only organic substituents have been varied,
either to optimize the catalyst’s performance, or to
introduce remote functional groups to immobilize the
catalyst on a solid support, we were interested in the
steric and electronic influences exhibited by ferrocenyl
substituents. Sterically, the ferrocenyl moiety represents
a quite bulky group with unique spatial requirements
w
x
stability and electronic structure 45–48 have been
published.
)
Corresponding author. E-mail: benno.bildstein@uibk.ac.at.
1 In part reported at the 213th National Meeting of the American
Chemical Society, San Francisco, CA, American Chemical Society,
Washington, DC, 1997, INOR 0188.
0022-328Xr98r$19.00 q 1998 Elsevier Science S.A. All rights reserved.

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)
46
B. Bildstein et al.rJournal of Organometallic Chemistry 552 1998 45–61
due to its cylindrical shape, and electronically, the
cenylbenzimidazoles 4 and 5 were prepared starting
from 2-bromoethyl ferrocene, which was synthesized
w
x
Ž .
powerful donor capacity of ferrocene 49 might in
principle be of advantage for an additional stabilization
of the electron-deficient carbene moiety.
Ž
.
w
x
from 2-hydroxyethyl ferrocene 57–62 , obtained by an
improved route from monolithioferrocene and ethylene
w
x
Here we report on the synthesis, spectroscopic prop-
erties, and X-ray structures of 1,3-ferrocenyl-alkyl sub-
stituted imidazoline-2-ylidene metal complexes. In this
work, the ferrocenyl groups are attached to the hetero-
oxide 63 . For electrochemical investigations of the
ferrocenylbenzimidazolium salts where iodide and bro-
Ž
mide oxidations overlap with the ferrocenerferro-
.
cenium couple in comparison to carbene complexes
Ž
cyclic carbene by means of an alkyl -CH2- and -CH2-
derived therefrom the corresponding tetraphenylborates
were obtained by anion exchange with sodium te-
traphenylborate in methanol solution.
.
CH2- spacer. This rules out any major electronic inter-
action with the imidazoline-2-ylidene, but the flexibility
of the alkyl spacer will minimize any disadvantageous
steric congestion in the carbene–metal complexes. The
electronic influence of the metallocenyl groups, directly
connected to the imidazoline without spacer, will be
Azolium salts 2a,b, 3a, 3b, 5 were subjected to some
Ž
.
typical carbene derivatizations Scheme 2 . Deprotona-
tion of 2a with n-BuLi and subsequent thionation with
elemental sulfur affords thiourea 6, in analogy to pub-
w x
lished work on other carbenes 22,35,36,64–67 . The
carbenes derived from 3a or 5 form with W CO THF
w
x
addressed in a forthcoming paper 50 .
Ž
.
5
the corresponding complexes 7 and 9, similar to the
reaction of other nucleophilic carbenes with metal car-
2. Results and discussion
w
x
bonyls 20–23,27,24–26 . In the case of 3a the reaction
does not only yield complex 7, but also nucleophilic
2.1. Synthesis
Ž
substitution products 8 which is simply the tungsten-
.
pentacarbonyl-complexed 1a and 2,3-dihydro-2-butyl-
Ž
.
The ferrocenylmethylation of imidazole or benzimi-
1,3-bis ferrocenylmethyl benzimidazole in low yield.
The formation of 8 is explainable by the electrophilic
property of 3a in analogy to trimethylammonium meth-
Ž
.
dazole Scheme 1 is most easily accomplished by
Ž
reaction of the corresponding heterocycle with tri-
.
w
x
methylammonium methylferrocene iodide, which has
ylferrocene iodide 51–56 with neutral 1a as leaving
Ž
.
long been known to be an excellent electrophile due to
the good leaving group property of trimethylamine 51–
group, which is complexed by W CO THF in a simple
5
w
ligand exchange reaction. The 2,3-dihydro-2-butyl benz-
imidazole side product arises from nucleophilic addition
x
56 . In this manner, mono- or di-substitution can be
Ž
.
achieved, affording 1a,b, 3a,b and the unsymmetrical
2a,b after quaternization with methyl iodide. In general,
imidazole derivatives 1b, 2b, 3b are obtained in inferior
yield in comparison to benzimidazole compounds 1a,
2a, 3a. Therefore most of the following chemistry
versus deprotonation , similar to the behavior of
azolium salts with sterically unhindered alcoholates
w
x
10,8,9,11,14,12,13,33,34,37,35,36 . As expected, reac-
Ž
.
tion of ethylene-spacered 5 with W CO THF yielded
5
complex 9 with no such unwanted nucleophilic addition
product analogous to 8, because no a-ferrocenyl-a-
azolium system is present.
Ž
.
metal complexes, see below was performed with the
benzimidazolium salts. The ethylene-spacered ferro-
Ž
.
Scheme 1. Synthesis of compounds 1a,b–5 Fcsferrocenyl; asbenzimidazole, bsimidazole, respectively .

(
)
B. Bildstein et al.rJournal of Organometallic Chemistry 552 1998 45–61
47
Ž
.
Ž .
Ž .
Scheme 2. Synthesis of compounds 6–15 Fcsferrocenyl; asbenzimidazole, bsimidazole, respectively . Reagents: i n-BuLi, Sel; ii BuLi,
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
W CO 5 PTHF; iii Pd OAc 2; iv Hg OAc .
2
Starting from carbene progenitors 2a,b, 3a,b, 5 and
features. For comparative purposes with the following
Ž .
Ž .
Pd II or Hg II acetates the corresponding metal car-
bene complexes 10–15 were synthesized by in situ
deprotonation with acetate as base and subsequent com-
carbene complexes, crystal structure analyses of 2a
Ž
.
Ž
.
Fig. 1, Table 1 and 3b Fig. 2, Table 1 were per-
formed. Besides the steric requirements of the ferro-
cenyl substituents, the interest in these and the follow-
ing structures focuses on the bonding situation at the
carbene carbon in terms of bond lengths and angles. As
Ž
.
Ž
plex formation Scheme 2 . This one pot reaction direct
metal complex synthesis without prior carbene forma-
.
w x
tion is based on work by Schonnher and Wanzlick 14
and, Wanzlick and Schonnher 12,13 , who isolated and
structurally characterized the first Hg II complex of a
¨
w
x
w
has been amply demonstrated by other workers 15–
¨
Ž .
x
23,27,24–26,28–34,37,35,36 , the C–N bond lengths of
w
x
nucleophilic carbene 14 as early as 1968. For four-co-
the carbene carbon are almost identical for imidazolium
salts, imidazoline and imidazolidine carbenes, and the
various metal complexes derived therefrom. Not surpris-
ingly, the carbene carbon in compounds 2a, 3b, 6, 7,
11, 13 has very similar bond lengths in comparison to
Ž .
ordinated Pd II complexes this method works only in
the presence of iodide as stabilizing additional ligand.
Ž
.
The iodide is usually and most conveniently supplied
‘internally’ as the counter ion of the azolium salt, but it
can also be added from an ‘external’ source of an
Ž
.
these published results for relevant data see Figs. 1–6 .
w
x
Ž
Ž . .
excess of NaI in the reaction mixture 34 . As expected,
Hg II complexes 12a,b, 14a,b and 15 with two carbene
The N–C–N angles in azolium salts 2a 109.9 8 8 and
Ž . .
Ž .
Ž
3b 109.0 3 8 compare well with those of reported
Ž Ž .
imidazolium carbene precursors e.g., 108.7 4 8 for
ligands per metal are ionic and hence very polar and
only slightly soluble compounds, but complex 13 with
stochiometrically one carbene moiety per metal unit
w
x.
1,3-dimesitylimidazolium 15 and, as will be seen in
the following, this angle decreases in the corresponding
carbene complexes in accord with published work on
Ž
which is the precursor complex of 12a and which could
.
w
therefore be isolated in only low yield is a dimer with
covalently bonded halogeno ligands and therefore much
other imidazoline-2-ylidene metal complexes 15–
x
23,27,24–26,28–34,37,35,36 .
Ž
.
more soluble see Section 2.2 for structural details .
Products 6–9 are simple carbene derivatives, which
were mainly synthesized to prove that these
Ž
.
2.2. Spectroscopic and structural properties
ferrocenyl benz imidazoline-2-ylidenes can be prepared
from the corresponding azolium salts 2a, 3a and 5 by
sequential deprotonation and reaction with the respec-
tive electrophiles. Thiourea 6 shows spectroscopic prop-
The spectroscopic properties of the carbene precur-
sors 2a,b, 3a,b, 5 are as expected and show no unusual

(
)
48
B. Bildstein et al.rJournal of Organometallic Chemistry 552 1998 45–61
Ž
.
Fig. 1. Molecular structure of 2a. Solvent molecules H2O, CH3OH and hydrogens are omitted for clarity. Selected bond lengths pm and angles
Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž .
N 2 s109.9 8 , C 12 –N 1 –C 19 s108.4 6 , C 12 –N 2 –C 14 s108.5 7 , N 1 –C 11 –C 10 s110.3 6 .
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž .
8 : C 12 –N 1 s133.9 9 , C 12 –N 2 s133.5 9 , N 1 –C 19 s139.8 9 , N 2 –C 14 s137.8 10 , C 14 –C 19 s139.4 10 ; N 1 –C 12 –
Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž .
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž .
erties in solution which are in line with the expectations
and the solid state structure Fig. 3 is very similar—
with regard to the thioimidazoline backbone–to a re-
Suitable single crystals for X-ray analysis could be
Ž
.
obtained for compounds 11 and 13. The palladium
Ž
.
complex 11 Fig. 6 shows the expected square-planar
coordination sphere at the Pd atom with trans-carbene
ligands. Due to the steric bulk of the ferrocenyl groups
they are arranged in an alternating up–down fashion,
thereby minimizing steric congestion. These sub-
w
x
cently published example 22 . Similarly, tungsten pen-
tacarbonyl complex 7 has unexceptional NMR spectro-
Ž
.
scopic properties and the X-ray structure Fig. 4 com-
pares well with analogous complexes reported by Her-
w
x
w x
Ž
.
rmann et al. 20–22 and Kuhn et al. 32 .
stituents and the iodo and benzimidazole ligands are
symmetrically related to each other by an inversion
center located on the central Pd atom. The benzimida-
zole rings are twisted against the square-planar coordi-
Whereas the NMR spectroscopic parameters of com-
pounds 6–9 can be interpreted in a straightforward
manner, this is not the case for palladium and mercury
complexes 10–15. Problems arise because these com-
pounds show only very limited solubility in common
organic solvents and the mercury complexes 12–15 tend
Ž
.
nation sphere by 85.17 23 8, similar as in other imidazo-
line-2-ylidene complexes 15–23,27,24–26,33,34,
w
x
Ž .
.
37,35,36 . The bond length Pd–Ccarbene of 202.4 7 pm
Ž
.
Ž
x
to decompose in solution compare experimental part .
In addition, for palladium compounds different di-
is in the usually observed range 195–207 pm for
w
palladium carbene complexes 25,34 .
Ž
astereoisomers are possible cis–trans, trans–syn,
trans–anti , depending on the substitution pattern of the
carbene ligand unsymmtric or symmetric and the steric
bulk of the N-substituents of the benz imidazole 25,34 .
Due to these difficulties the most useful information
can be obtained from mass spectroscopy and from
X-ray structures. The identities of palladium complexes
10 and 11 are clearly established by observation of the
As mentioned earlier, the first bis-imidazolin-2-
.
Ž .
ylidene Hg II complex was isolated by Schonherr and
¨
Ž
.
w x w x
Wanzlick 14 and, Wanzlick and Schonherr 12,13 and
¨
Ž
.
w
x
w
x
structurally characterized 14,68 , showing the expected
linear coordination with a Ccarbene–Hg distance of 206 1
Ž .
pm. Most likely all of the analogous bis-carbene com-
plexes 12a,b, 14a,b, and 15 in this work will have a
similar structure with regard to the coordination at
mercury. All attempts to obtain suitable single crystals
for these complexes failed, except for the dimeric
Ž
Ž
.
molecular ions mrzs1020 and 1388, respectively as
.
the base peaks 100% in the FAB-mass spectra. The
more polar and less soluble ionic mercury complexes
12–15 require electrospray ionization to obtain useful
data. In general, the highest signal observed is the
monocation corresponding to the formula mass of the
Ž
.
mono-carbene complex 13 Fig. 7 . The molecule exists
as a dimer with trans-carbene ligands and with bridging
Ž
Ž . Ž .
Ž .
.
Ž
Ž .
Hg 1 –I 2 s289.42 7 pm and non-bridging Hg 1 –
Ž .
Ž .
.
I 1 s270.91 8 pm iodine ligands. An inversion cen-
Ž
.
complexes minus one halogenide Fig. 5 .
ter located in the center of the central Hg2 I2-rhombus

(
)
B. Bildstein et al.rJournal of Organometallic Chemistry 552 1998 45–61
49
c
c
c
c
c
c
s
s
a
b
g
u

(
)
50
B. Bildstein et al.rJournal of Organometallic Chemistry 552 1998 45–61
Ž .
Ž .
Fig. 2. Molecular structure of 3b. Hydrogen atoms are omitted for clarity. Cyclopentadienyl carbons of ferrocene 1 are C 1 –C 10 and for
Ž
.
Ž
.
Ž
.
Ž .
Ž
.
Ž .
Ž
Ž .
Ž
.
Ž .
Ž . Ž .
.
Ž
Ž
.
.
ferrocene 2 C 16 –C 25 , respectively. Selected bond lengths pm and angles 8 : C 12 –N 1 s131.7 5 , C 12 –N 2 s132.9 5 , N 1 –C 13
Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž .
Ž
.
Ž
.
Ž
.
Ž
.
.
Ž
.
Ž
s137.7 5 , N 2 –C 14 s137.5 5 , C 13 –C 14 s133.8 6 ; N 1 –C 12 –N 2 s109.0 3 , C 12 –N 1 –C 13 s108.1 3 , C 12 –N 2 –C 14
Ž . Ž . Ž . Ž . Ž .
Ž
.
Ž
.
Ž
.
Ž .
s108.5 3 , N 1 –C 11 –C 10 s112.7 3 , N 2 –C 15 –C 16 s110.8 3 .
Ž
Ž . Ž .
Ž
.
Ž . .
Hg 1 –I 2 –Hg 1a s86.18 2 8 interconverts the io-
The presence of ferrocenyl substituents in com-
dine and carbene ligands. The coordination sphere of
mercury is more or less tetrahedral, with some distor-
pounds 1–15 allows in principle electrochemical mea-
q
Ž
.
surements of the ferrocenerferrocenium FcrFc cou-
ple. Unfortunately, if iodine or bromine ligands are
present, no clean cyclovoltammograms were obtained
due to signal overlapping; therefore only the non-halo-
gen containing azolium salts and metal complexes could
be investigated electrochemically. Because in this series
of compounds the ferrocenyl electrophor is separated by
a non-conjugated saturated alkyl spacer, we did not
Ž Ž .
.
Ž . Ž .
Ž . Ž .
Ž .
Ž
Ž .
tions C 12 –Hg 1 –I 1 s131.4 2 8, I 2 –Hg 1 –I 2a
Ž . .
s93.82 2 8 . The metal–carbene bond length Hg 1 –
Ž
.
Ž .
C 12 of 214.7 7 pm is elongated in comparison to
Ž .
Ž
Wanzlick’s bis-carbene complex Ccarbene–Hgs206 1
w
x.
pm 14,68 , but shorter than in the comparable mercury
x2 Ž .
w
Ž
.
Ž
.
dimer
C6 H5 3 P Cp HgI2
,
C–Hg s 229 2 pm
w
x
69,70 , due to partial double bonding in 13.
Ž . .
Ž
.
Ž
Fig. 3. Molecular structure of 6. Hydrogen atoms are omitted for clarity. Cp carbons of ferrocene 1 are C 1 –C 10 . Selected bond lengths pm
Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž .
Ž
.
Ž
.
Ž
.
Ž
Ž
.
.
Ž
.
Ž .
and angles 8 : C 12 –S 1 s165.9 3 , C 12 –N 1 s136.5 3 , C 12 –N 2 s136.5 3 , N 1 –C 19 s139.1 3 , N 2 –C 14 s137.8 4 , C 14 –
Ž
.
Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž .
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž .
C 19 s139.9 3 ; N 1 –C 12 –N 2 s106.6 2 , C 12 –N 1 –C 19 s109.9 2 , C 12 –N 2 –C 14 s110.3 2 , N 1 –C 11 –C 10 s111.4 2 .

(
)
B. Bildstein et al.rJournal of Organometallic Chemistry 552 1998 45–61
51
Ž .
Ž .
Fig. 4. Molecular structure of 7. Hydrogen atoms are omitted for clarity. Cyclopentadienyl carbons of ferrocene 1 are C 6 –C 15 and for
Ž
.
Ž
Ž
.
.
Ž
.
.
Ž
.
Ž
Ž
.
Ž .
ferrocene 2 C 19 –C 28 , respectively. Phenylene carbons of benzimidazoline are C 29 –C 34 . Selected bond lengths pm and angles 8 :
Ž
.
Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž .
Ž
.
Ž
.
Ž
.
.
Ž
.
Ž
Ž
.
.
.
Ž .
C 17 –W 1 s226.4 14 , C 17 –N 1 s135.0 2 , C 17 –N 2 s135.7 14 , N 1 –C 30 s138 2 , N 2 –C 29 s139 2 , C 29 –C 30 s139 2 ;
Ž . Ž . Ž . Ž . Ž . Ž . Ž .
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž
Ž
Ž
.
Ž
.
Ž .
N 1 –C 17 –N 2 s103.3 11 , C 17 –N 1 –C 30 s112.4 10 , C 17 –N 2 –C 29 s113.4 11 , N 1 –C 16 –C 15 s113.4 9 , N 2 –C 18 –
Ž
.
Ž .
C 19 s116.3 11 .
q
Ž
.
Ž
.
Ž
.
Fig. 5. q ESI mass spectrum of 12a C38 H36 N4 Fe2 HgI2; Mr s1114.82 grmole ; mrzs987 75% corresponds to M minus one iodine.

(
)
52
B. Bildstein et al.rJournal of Organometallic Chemistry 552 1998 45–61
Fig. 6. Molecular structure of 11. Hydrogen atoms and dichloromethane molecules are omitted for clarity. Cyclopentadienyl carbons of ferrocene
Ž . Ž . Ž . Ž .
Ž
.
Ž
.
Ž
.
Ž
.
Ž .
1 are C 1 –C 10 and for ferrocene 2 C 20 –C 29 , respectively. Selected bond lengths pm and angles 8 : C 12 –Pd 1 s202.4 7 ,
Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž .
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž .
Pd 1 –I 1 s259.05 7 , C 12 –N 1 s135.5 9 , C 12 –N 2 s135.4 9 , N 1 –C 15 s140.1 9 , N 2 –C 14 s139.5 9 , C 14 –C 15 s
Ž
.
Ž
.
Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž .
Ž
.
Ž
Ž
.
Ž
.
Ž .
Ž
.
Ž
.
Ž .
137.4 10 ; C 12 –Pd 1 –C 12a s180.0, C 12 –Pd 1 –I 1 s88.6 2 , N 1 –C 12 –N 2 s106.0 6 , C 12 –N 1 –C 15 s110.3 5 , C 12 –
Ž .
Ž
.
Ž . Ž .
.
Ž
.
Ž . Ž .
Ž
.
Ž
.
N 2 –C 14 s110.9 6 , N 1 –C 11 –C 10 s113.0 5 , N 2 –C 13 –C 20 s112.9 6 .
Fig. 7. Molecular structure of 13. Hydrogen atoms and DMF molecules are omitted for clarity. Cyclopentadienyl carbons of ferrocene 1 are
Ž
.
Ž
.
Ž
.
Ž .
Ž
.
Ž .
Ž .
Ž . Ž .
Ž .
Ž . Ž .
Ž .
Ž
.
Ž
.
C 1 –C 10 . Selected bond lengths pm and angles 8 : C 12 –Hg 1 s214.7 7 , Hg 1 –I 1 s270.91 8 , Hg 1 –I 2 s289.42 7 , C 12 –N 1
Ž
.
Ž
.
Ž . Ž . Ž . Ž . Ž . Ž . Ž .
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
s 134.8 10 , C 12 –N 2 s 133.8 10 , N 1 –C 15 s 139.5 10 , N 2 –C 14 s 140.3 9 , C 14 –C 15 s 138.5 10 ; I 2 –Hg 1 –I 2a s
Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž .
Ž
.
Ž
.
.
Ž
.
Ž
.
Ž
.
Ž .
93.82 2 , C 12 –Hg 1 –I 1 s131.4 2 , C 12 –Hg 1 –I 2 s111.4 2 , C 12 –Hg 1 –I 2a s104.1 2 , N 1 –C 12 –N 2 s106.4 6 , C 12 –
Ž . Ž . Ž . Ž . Ž . Ž .
Ž
.
Ž
.
Ž
Ž
.
Ž .
N 1 –C 15 s110.5 6 , C 12 –N 2 –C 14 s111.3 6 , N 1 –C 11 –C 10 s112.6 6 .

(
)
B. Bildstein et al.rJournal of Organometallic Chemistry 552 1998 45–61
53
Ž
.
Ž
.
CH-7 EI-MS , Finnigan MAT 95 FAB-, ESI-MS .
Melting points were determined on a Leica–Reichert
VM-TG hot plate apparatus. Microanalyses were ob-
tained from the Analytical Department of Lenzing AG,
Lenzing, Austria.
Cyclic voltammetric measurements were performed
Ž
at room temperature with a POS 88 Potentiostat Bank
.
Elektronik , using a standard three electrode apparatus,
an atmosphere of purified argon, acetonitrile as solvent,
a scan rate of 100 mVrsec, and 0.1 M tetrabutylammo-
Ž
w
x
.
nium hexafluorophosphate TBA PF6 as the conduct-
ing salt. The signals were referenced to the saturated
Ž
.
calomel electrode SCE by calculating the correspond-
ing half wave potentials from cobaltoceniumrcobalto-
Fig. 8. Cyclic voltammetry of 3a and 7.
Ž
cene as an internal standard versus SCE SCE; E1r2
s
.
y0.93 V .
expect any major changes in comparison to the parent
FcHrFcHq couple. Surprisingly, significant relative
shifts in the half-wave potential from y120 mV to
q130 mV were observed. Tetraphenylborates 2a, 3a, 5
show values of 0.57, 0.58, 0.45 V, and carbene deriva-
tives 6, 7, 9 values of 0.47, 0.53, 0.43 V, respectively.
In each case only one reversible FcrFcq wave is
observed, irrespective of the number of ferrocenyl sub-
stituents Fig. 8 . Although no simple interpretation of
these data in terms of some linear correlation can be
envisaged at this point, the different electrochemical
response might serve as an additional distinguishing
property in this series of compounds.
4.2. X-ray structure determinations of 2a, 3b, 6, 7, 11,
13
A Siemens P4 diffractometer with graphite-mono-
Ž
.
chromatized Mo–K a radiation ls71.073 pm was
used for data collection. Crystal data, data collection,
and refinement parameters of 2a, 3b, 6, 7, 11, 13 are
summarized in Table 1. The unit cells were determined
by the automatic indexing of 25 centered reflections and
confirmed by examination of the axial photographs.
Data were measured via v-scan and corrected for
Lorentz and polarization effects. Scattering factors for
neutral atoms and anomalous dispersion corrections were
taken from the International Tables for X-ray Crystal-
Ž
.
w
x
3. Conclusions
lography 71 and an empirical absorption correction
w
x
72,73 was made. The structures were solved by direct
w
x
A number of imidazolium and benzimidazolium salts
methods, SHELXS86 74 , and refined by a full matrix
least-squares procedure using SHELXL-93 75 . All
non-hydrogen atoms were refined with anisotropic dis-
X
Ž
.
Ž .
w
x
with N,N -alkyl ferrocenyl substituents has been pre-
Ž .
Ž .
pared and converted to W 0 , Pd II , and Hg II metal
carbene complexes. X-ray structures show that the bulky
ferrocenyl groups effectively shield the central metal
core and cyclovoltammetric measurements of the fer-
roceniumrferrocene couple reveal distinguishable half-
wave potentials. These carbene derivatives are the first
examples of such imidazoline-2-ylenes incorporating an
organometallic moiety and they might prove useful in
potential applications in homogenous catalysis.
Ž
.
placement parameters Tables 2–7 , except for 7 due to
Ž
insufficient datarparameter ratio compare note in Table
.
5 . Hydrogen atoms were placed in calculated positions.
The authors have deposited atomic coordinates for
structures 2a, 3b, 6, 7, 11, 13 at the Cambridge Crystal-
lographic Data Centre. The coordinates can be obtained,
on request, from the Director, Cambridge Crystallo-
graphic Data Centre, Lensfield Road, Cambridge, CB2
1EW, UK.
(
)
(
4. Experimental section
4.3. N- ferrocenylmethyl benzimidazole 1a and n- fer-
)
rocenylmethyl imidazole 1b
4.1. General techniques and instrumentation
Ž
.
N- ferroenylmethyl benzimidazole is a known com-
w
x
Reactions of air-sensitive materials were carried out
using standard Schlenk techniques and vacuum-line ma-
nipulations. Solvents were deoxygenated, purified and
pound 76,77 , but no physical or spectroscopic data
have been published, therefore we describe its prepara-
tion and properties in detail. A mixture of 2 g 5.2
Ž
dried prior to use. Instrumentation: Bruker AC 200 1H,
Ž
.
w
Ž
.
x
m m ol
1
g
2.6 m m ol , respectively
13C; 1H and 13C signals were referenced to internal
Ž
.
w
x
ferrocenylmethyl trimethyl ammonium iodide 51–56
and 0.766 g 6.5 mmol benzimidazole 0.22 g 3.2
.
Ž
.
Ž
.
w
Ž
residual solvent peaks ; Nicolet 510 FT-IR IR ; Varian

(
)
54
B. Bildstein et al.rJournal of Organometallic Chemistry 552 1998 45–61
FcCH2 , 188.5 44 M –Cp , 121 83 FeCp . 1H
q
Table 2
Ž
.
Ž
. Ž
.
Ž
. Ž
.
4
Ž
.
Atomic coordinates 10 and equivalent isotropic displacement pa-
rameters pm =10
Ž
.
Ž
.
NMR CDCl3 : d 4.13 m, 7H, Cpsubst and Cpunsubst ,
4.16 m, 2H, Cpsubst , 4.82 s, 2H, CH2 , 6.87 s, 1H,
2
y1
Ž
.
for 2a
Ž
.
Ž
.
Ž
Ž
Ž
x
y
z
U
eq
.
Ž
.
imidazole , 6.99 s, 1H, imidazole , 7.44 s, 1H, imida-
zole . 13C NMR DMSO-d6 : d 44.7 CH2 , 68.5
Ž Ž .
Ž .
Fe 1
Ž .
3999 1
3452 1
3467 4
3914 4
Ž .
Ž .
y147 1
Ž .
28 1
1331 1
4425 1
2550 4
3212 4
.
Ž
.
.
Ž .
Ž .
Ž .
Ž .
Ž .
67 1
I 1
1842 1
Ž
.
Ž
.
Ž
.
.
Cpsubst , 68.7 Cpsubst , 68.73 Cpunsubst , 80.0 C 1 of
Ž .
Ž .
Ž .
Ž .
Ž .
30 2
N 1
y3214 5
y4573 5
.
Ž
Cpsubst ; 118.8, 129.1, 136.6 imidazole .
Ž .
Ž .
Ž .
Ž .
Ž .
37 2
N 2
Ž .
Ž .
Ž
.
.
Ž .
842 8
Ž .
77 4
C 1
3150 7
1157 12
Ž .
Ž .
Ž
.
Ž .
Ž .
76 4
(
)
C 2
3769 11
Ž .
740 6
1230 9
4.4. 1- Ferrocenylmethyl -3-methyl-benzimidazolium io-
dide and tetraphenylborate 2a and 1-
Ž .
Ž
Ž .
Ž .
Ž .
68 3
C 3
4296 6
1310 11
2055 7
Ž .
1984 8
843 5
Ž .
510 5
1131 6
Ž .
1871 5
1705 5
Ž .
2317 5
3218 5
Ž .
3841 5
2518 5
Ž .
2228 6
1503 6
Ž .
1080 5
1410 6
Ž .
Ž .
Ž .
Ž .
56 3
C 4
4025 7
3343 8
1161 8
(
)
ferrocenylmethyl -3-methyl-imidazolium iodide 2b
Ž .
Ž .
Ž .
Ž .
60 3
C 5
804 7
Ž .
Ž .
Ž .
Ž .
Ž .
28 2
C 6
3752 4
Ž .
y1612 5
Ž
.
Ž
0.2 g 0.6 mmol of 1a was dissolved in 1 ml 16
Ž .
Ž .
y1200 6
Ž .
37 2
C 7
4401 5
Ž .
Ž .
Ž .
Ž .
Ž .
37 2
.
C 8
4911 4
4575 4
y1022 6
mmol methyl iodide and refluxed for 2 h. The resulting
precipitate of crude 2a-iodide was filtered off and
washed with small portions of ether until the ether
fractions were colorless. Yield: 0.285 g 0.6 mmol,
98% . Conversion of the 2a-iodide into 2a-tetraphenyl-
borate: a solution of the iodide 0.108 g, 0.24 mmol in
methanol was added to a solution of NaB C6 H5 0.12
g, 0.35 mmol in methanol, the resulting 2a-tetraphenyl-
borate was filtered off, washed with three portions of
Ž .
C 10
Ž .
Ž .
y1318 6
Ž .
31 2
C 9
Ž
.
.
.
.
.
.
.
.
.
.
Ž .
Ž .
Ž .
Ž .
26 2
3854 4
Ž .
y1691 5
Ž
Ž .
y2079 6
Ž .
30 2
C 11
3316 4
Ž
Ž
Ž .
Ž .
Ž .
Ž .
36 2
C 12
3825 5
4292 5
y3513 7
.
Ž
Ž .
Ž .
y5172 7
Ž .
58 3
C 13
Ž
Ž .
Ž .
Ž .
Ž .
30 2
Ž
.
C 14
3599 4
Ž .
y4985 6
Ž
Ž .
y6042 6
Ž .
40 2
C 15
3542 5
Ž
. Ž
4
Ž
Ž .
Ž .
Ž .
Ž .
50 3
C 16
3168 5
2870 5
y6156 6
.
Ž
Ž .
Ž .
y5306 7
Ž .
49 3
C 17
Ž
Ž .
Ž .
Ž .
Ž .
34 2
C 18
2939 4
Ž .
1375 5
2093 5
4020 5
4602 13
y4270 6
Ž
Ž .
Ž .
y4131 6
Ž .
25 2
C 19
3303 4
Ž .
Ž .
Ž .
Ž .
y958 7
Ž .
132 3
O 1
3931 5
4822 10
4822 10
Ž
.
.
Ž
Ž
.
.
Ž
Ž
.
.
Ž
.
.
Ž .
116 8
C 20
y2030 15
Table 3
Ž
Ž
y2030 15
Ž .
116 8
O 20
4602 13
4
Ž
.
Atomic coordinates 10 and equivalent isotropic displacement pa-
2
y1
Ž
.
U
is defined as one third of the trace of the orthogonalized Uij
rameters pm =10
for 3b
eq
tensor.
x
y
z
U
eq
Ž .
Fe 1
Fe 2
Ž .
y3812 1
Ž .
3758 1
3800 1
Ž .
3382 1
1555 1
Ž .
48 1
Ž .
Ž .
2549 1
Ž .
Ž .
Ž .
40 1
.
x
mmol imidazole respectively in 10 ml DMF was re-
fluxed for 2 h. The brown solution was hydrolized with
100 ml H2O and extracted with five portions of ether.
The combined organic layers were washed with three
portions of H2O, dried with Na2 SO4, and evaporated to
Ž .
Ž .
Ž .
Ž .
Ž .
66 1
I 1
722 1
7244 1
218 1
Ž .
Ž .
Ž .
Ž .
Ž .
42 1
N 1
y1101 2
4857 2
3493 3
Ž .
Ž .
12 2
Ž .
Ž .
Ž .
39 1
N 2
4989 2
2333 3
Ž .
Ž .
Ž .
Ž .
Ž .
84 2
C 1
y3526 4
2573 4
4205 7
Ž .
Ž .
Ž .
Ž .
Ž .
80 2
C 2
y4356 4
2535 4
3445 6
Ž .
Ž .
Ž .
Ž .
Ž .
74 2
C 3
y4928 3
3148 4
3935 6
Ž
dryness on a rotary evaporator, yielding 1.321 g 4.2
mmol, 77.3% 1a and 0.39 g 1.5 mmol, 54% 1b,
respectively.
Ž .
Ž .
Ž .
Ž .
Ž .
80 2
C 4
y4458 4
3562 4
5003 5
.
Ž
.
Ž .
Ž .
Ž .
Ž .
Ž .
87 2
C 5
y3599 4
3204 5
5160 6
Ž .
Ž .
Ž .
Ž .
Ž .
54 1
C 6
y2913 3
3943 3
2046 4
Ž .
Ž .
Ž .
Ž .
Ž .
64 1
C 7
y3795 3
4139 4
1493 4
Data for 1a: yellow crystals, m.p. 119–1228C. Anal.
Found: C, 68.42; H, 5.13 C18 H16 FeN2. Calcd.: C,
Ž .
Ž .
y4141 3
Ž .
Ž .
Ž .
62 1
C 8
4816 3
2216 5
Ž .
C 10
Ž .
Ž .
Ž .
Ž .
50 1
C 9
Ž
y3483 3
5054 3
3237 4
y1
Ž
.
68.38; H, 5.10%. IR KBr : cm 3077w, 2927w, 1489s,
1456m, 1443s, 1348w, 1283m, 1263s, 1157w, 1101s,
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Ž .
y2720 2
Ž .
Ž .
Ž .
44 1
4502 3
3134 4
Ž
Ž .
Ž .
Ž .
Ž .
48 1
C 11
y1891 3
4478 3
4055 4
Ž
Ž .
y648 3
Ž .
Ž .
Ž .
44 1
C 12
4462 3
2630 4
Ž
1038m, 1026s, 1003w, 739s, 509s, 488s. MS EI, 70
, 199 61 FcCH2 . 1H
Ž
Ž .
Ž .
Ž .
Ž .
q
C 13
y707 3
5662 3
Ž .
3775 4
Ž .
50 1
.
Ž
.
Ž
. Ž
.
Ž
. Ž
.
eV : mrz % 316 100
M
Ž
Ž .
y17 3
Ž .
C 14
5748 3
3050 4
51 1
Ž
.
Ž
.
Ž
NMR DMSO-d6 : d 4.15 m, 2H, Cpsubst , 4.16 s, 5H,
Cpunsubst , 4.23 m, 2H, Cpsubst , 5.05 s, 2H, CH2 ,
7.25–7.88 m, 5H, benzimidazole . C NMR DMSO-
d6 : d 44.7 CH2 , 68.77 Cpunsubst and Cpsubst , 82.04
Ž
Ž .
Ž .
Ž .
Ž .
C 15
689 2
4758 3
1438 4
44 1
.
Ž
.
Ž
.
Ž
Ž .
Ž .
Ž .
Ž .
38 1
C 16
1581 2
4589 2
2172 4
13
Ž
.
Ž
Ž
Ž .
Ž .
Ž .
Ž .
57 1
C 17
2375 3
5077 3
2089 5
Ž
Ž .
Ž .
Ž .
Ž .
59 1
C 18
3073 3
4664 3
2929 5
.
Ž
.
Ž
.
Ž
Ž .
Ž .
Ž .
Ž .
58 1
C 19
2697 3
3947 3
3505 4
Ž Ž .
.
Ž
C 1 of Cpsubst ; 109.7, 120.34, 122.0, 122.8 be-
Ž
Ž .
Ž .
Ž .
3062 4
Ž .
49 1
C 20
1780 3
3894 3
.
nzimidazole .
Ž
Ž .
Ž .
Ž .
Ž .
C 21
2059 4
3231 7
y124 7
96 2
Ž .
113 3
Data for 1b: yellow crystals, m.p. 79–818C. Anal.
Ž
Ž .
Ž .
Ž .
532 10
C 22
2821 8
3682 5
y319 6
Ž
Ž .
Ž .
Ž
.
Ž .
117 3
Found: C, 63.24; H, 5.32 C14 H14 FeN2. Calcd.: C,
C 23
3507 4
3313 8
y1
Ž
Ž .
Ž .
Ž .
Ž .
123 3
C 24
3148 8
2669 6
1161 8
Ž
.
63.19; H, 5.30%. IR KBr : cm
3106w, 2963w,
Ž
Ž .
2272 7
Ž .
2622 6
Ž .
Ž .
121 3
C 25
778 10
1510m, 1283m, 1261s, 1236m, 1225m, 1103s, 1080s,
1040s, 1028s, 804s, 744m, 667w, 617w, 503s, 482s.
U
tensor.
is defined as one third of the trace of the orthogonalized Uij
eq
q
Ž
.
Ž
.
Ž
. Ž
.
Ž
.
MS EI, 70 eV : mrz % 266 100
M
, 199 96

(
)
B. Bildstein et al.rJournal of Organometallic Chemistry 552 1998 45–61
55
Table 4
Atomic coordinates 10 and equivalent isotropic displacement pa-
.
of Cpsubst ; 114.8, 114.9, 118.9, 123.4, 127.1, 127.2,
4
Ž
.
Ž
127.2, 127.3, 128.4, 128.5, 137.3, 142.0 benzimidazole
2
y1
Ž
.
rameters pm =10
for 6
.
Ž
. w x
and tetraphenylborate . CV CH3CN; 208C V : 0.57.
Data for 2b-iodide: yellow crystals, m.p. 145–1488C.
Anal. Found: C, 44.20; H, 4.18. C1y5 H1 17 FeIN2. Calcd.:
x
y
z
U
eq
Ž .
Fe 1
S 1
Ž .
9856 1
4384 1
Ž .
292 1
2728 1
Ž .
1569 1
Ž .
24 1
2921 1
Ž .
Ž .
Ž .
Ž .
Ž .
41 1
Ž
.
C,44.15; H, 4.20%. IR KBr : cm
1570s, 1238m,
Ž .
Ž .
Ž .
Ž .
Ž .
26 1
N 1
4837 2
396 2
1599 1
1157s, 1105s, 1040s, 1028m, 1001s, 828s, 773m, 621s,
Ž .
Ž .
Ž .
Ž .
Ž .
30 1
N 2
3252 2
1029 2
593 1
q
Ž
.
Ž
.
.
Ž
. Ž
503s, 484s. MS FAB : mrz % 281 100 M
of
.
Ž .
Ž .
Ž .
Ž .
Ž .
38 1
C 1
10165 3
y778 2
3846 2
1
Ž .
Ž .
Ž .
Ž .
Ž .
.
Ž
Ž
C 2
11721 3
y330 3
3699 2
42 1
cation . H NMR DMSO-d6 : d 3.80 s, 3H, CH3 ,
Ž .
Ž .
Ž .
891 3
Ž .
Ž .
C 3
11638 3
3746 2
44 1
Ž .
Ž .
Ž .
Ž .
Ž .
42 1
C 4
10039 4
1198 3
3917 2
Ž .
Ž .
Ž .
Ž .
Ž .
39 1
C 5
9131 3
172 3
3979 2
Ž .
Ž .
Ž .
Ž .
Ž .
32 1
C 6
8740 3
y650 2
2030 1
Table 5
4
Ž .
Ž .
Ž .
y262 3
Ž .
Ž .
42 1
Ž
.
C 7
10333 3
1884 2
Atomic coordinates 10 and equivalent isotropic displacement pa-
rameters pm =10
2
y1
Ž .
Ž .
Ž .
Ž .
Ž .
41 1
Ž
.
C 8
10354 3
963 3
1912 2
for 7
Ž .
C 10
Ž .
Ž .
Ž .
Ž .
33 1
C 9
Ž
8775 3
1347 2
2075 1
x
y
z
U
eq
.
.
.
.
.
.
.
.
.
.
Ž .
Ž .
Ž .
Ž .
25 1
7766 3
351 2
2155 1
Ž .
W 1
Fe 1
Ž .
10128 1
5439 2
12228 1
11757 8
9019 8
11629 9
11749 8
8704 8
7887 8
Ž .
9267 8
11140 11
9355 12
11078 12
11100 12
9208 10
6120 11
5182 12
4293 10
4636 11
5764 11
6537 11
5511 14
4709 12
5219 11
6351 10
7179 10
8987 12
10390 12
10680 9
10944 13
11179 13
11144 12
Ž .
7082 1
9156 2
Ž .
3117 1
3284 1
Ž .
32 1
Ž
Ž .
Ž .
Ž .
2310 1
Ž .
26 1
C 11
5994 3
372 2
Ž .
Ž .
Ž .
Ž .
Ž .
33 1
Ž
Ž .
Ž .
Ž .
1251 1
Ž .
28 1
C 12
4174 3
1376 2
Ž .
Ž .
Ž .
Ž .
Ž .
37 1
Fe 2
2654 2
4601 1
Ž
Ž .
Ž .
Ž .
69 2
Ž .
44 1
C 13
2237 3
1791 3
Ž .
Ž .
Ž .
Ž .
Ž .
Ž .
Ž .
Ž
.
Ž .
Ž .
71 3
O 1
8654 11
2427 4
Ž
Ž .
Ž .
Ž .
517 1
Ž .
29 1
C 14
3335 3
y157 2
Ž .
Ž
.
Ž .
Ž .
58 3
O 2
10003 12
3361 4
Ž
Ž .
Ž .
y907 3
Ž .
y46 2
Ž .
40 1
C 15
2623 3
Ž .
Ž
.
.
.
.
.
.
.
.
.
.
Ž .
Ž .
92 4
O 3
7790 14
4100 4
Ž
Ž .
Ž .
Ž .
Ž .
49 1
C 16
2964 4
y2071 3
60 2
Ž .
Ž
Ž .
Ž .
60 3
O 4
4638 11
2837 4
Ž
Ž .
Ž .
y2484 3
Ž .
Ž .
45 1
C 17
3954 4
706 2
Ž .
Ž
Ž .
Ž .
60 3
O 5
6551 10
2081 4
Ž
Ž .
Ž .
Ž .
Ž .
34 1
C 18
4650 3
y1741 2
1270 2
Ž .
Ž
Ž .
Ž .
23 3
N 1
5738 11
3567 4
Ž
Ž .
Ž .
y570 2
Ž .
Ž .
26 1
C 19
4345 3
1158 1
Ž .
Ž
Ž .
Ž .
N 2
4587 12
3860 4
Ž .
35 3
Ž .
Ž
.
Ž
Ž .
C 1
8143 17
2707 5
50 4
U
is defined as one third of the trace of the orthogonalized Uij
eq
Ž .
Ž
.
Ž
Ž .
Ž .
C 2
8910 17
3270 5
51 4
Ž .
tensor.
Ž .
Ž
Ž
.
.
Ž
Ž .
C 3
Ž .
7479 16
3740 6
58 5
Ž
Ž .
Ž .
C 4
5456 16
2945 5
Ž .
46 4
Ž .
39 4
Ž
.
Ž .
Ž
.
.
.
.
.
.
.
.
.
.
.
.
.
Ž
methanol, and dried in vacuo, yielding 92 mg 60%
C 5
6709 14
2458 5
Ž .
Ž
Ž
.
.
.
Ž .
Ž .
C 6
10669 15
11194 14
10408 15
2847 5
43 4
Ž .
44 4
2a-tetraphenylborate. Analogously, 2b-iodide was pre-
pared from 1b with methyl iodide in 87% yield.
Data for 2a-iodide: yellow crystals, m.p. 116–1188C.
Anal. Found: C, 49.75; H, 4.21 C1y9 H1 19 FeIN2. Calcd.:
Ž .
Ž
Ž
Ž .
C 7
3080 5
Ž .
Ž
Ž
Ž .
Ž .
C 8
2923 5
Ž .
39 4
Ž .
42 4
Ž .
C 10
Ž
Ž
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
C 9
Ž
9358 15
2585 5
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Ž
Ž
Ž .
Ž .
9523 15
2534 5
38 4
Ž .
33 4
Ž
.
Ž
Ž
Ž
Ž .
C, 49.81; H, 4.18%. IR KBr : cm
3015w, 2969w,
C 11
8672 15
3866 5
Ž
Ž
Ž
Ž .
Ž .
C 12
9087 17
4061 5
Ž .
47 4
Ž .
49 4
1609w, 1565s, 1463s, 1432m, 1347w, 1329s, 1238m,
1105s, 1013s, 1003w, 828s, 812m, 783w, 764s, 501s,
Ž
Ž
Ž
C 13
8183 19
3857 6
Ž
Ž
Ž
Ž .
Ž .
C 14
7224 15
3546 5
35 4
Ž .
30 4
1
q
Ž
.
Ž
.
Ž
. Ž
.
482m. MS FAB : mrz % 331 100
M
of cation . H
Ž
Ž
Ž
Ž .
C 15
7472 14
3544 5
Ž
.
Ž
.
Ž
NMR CDCl3 : d 4.19 s, 3H, CH3 , 4.21 m, 2H,
Cpsubst , 4.29 s, 5H, Cpunsubst , 4.58 m, 2H, Cpsubst ,
5.61 s, 2H, CH2 , 7.63–10.9 m, 5H, benzimidazole .
Ž
Ž
Ž
Ž .
Ž .
C 16
6686 13
3244 4
Ž .
28 4
Ž .
28 4
.
Ž
.
Ž
.
Ž
Ž
Ž
C 17
5719 14
3562 4
Ž
Ž
.
Ž
Ž .
Ž .
64 5
C 18
4014 18
3904 6
Ž
.
Ž
.
13
Ž
Ž .
Ž
Ž .
Ž .
28 4
C 19
3183 15
4372 5
Ž
.
Ž
.
Ž
.
C NMR DMSO-d6 : d 33.4 CH3 , 46.4 CH2 , 68.9
Ž Ž .
Ž
Ž
.
.
.
.
.
.
.
.
.
Ž
Ž .
Ž .
61 5
C 20
3725 19
4858 7
Ž
.
Ž
.
Ž
.
Cpunsubst , 69.0 Cpsubst , 69.6 Cpsubst , 80.0 C 1 of
Ž
Ž
Ž
Ž .
Ž .
62 6
C 21
2650 25
5190 6
.
Ž
Cpsubst ; 113.6, 113.8, 126.6, 130.5, 131.8, 141.9 be-
Ž
Ž
Ž
Ž .
Ž .
61 6
C 22
1351 20
4933 8
.
Ž
.
Ž
Ž
Ž
Ž .
Ž .
54 5
nzimidazole . X-ray structure Tables 1 and 2; Fig. 1 :
single crystals were obtained from dichloromethane.
Data for 2a-tetraphenylborate: yellow crystals, m.p.
165–1678C. Anal. Found: C, 79.37; H, 6.07.
C43 H39 FeBN2. Calcd.: C, 79.40; H, 6.04%. IR KBr :
cmy1 3069m, 3056m, 2983w, 1564s, 1479s, 1427m,
1109w, 1030m, 1009w, 852m, 825m, 816m, 744s, 733s,
708s, 615m, 603s, 497m, 492m, 482m. MS FAB :
of cation . H NMR CD3CN :
d 3.80 s, 3H, CH3 , 4.26 m, 2H, Cpsubst , 4.27 s, 5H,
C 23
10831 12
13235 11
13457 12
13750 11
13717 10
13386 10
8382 11
7483 11
6447 12
6315 10
7196 12
8246 11
1666 18
4400 6
Ž
Ž
Ž
Ž .
Ž .
52 4
C 24
3336 15
4060 5
Ž
Ž
Ž
Ž .
Ž .
60 5
C 25
4082 17
4506 6
Ž
Ž
Ž
Ž .
Ž .
51 4
C 26
3072 17
4900 5
Ž
Ž
Ž
Ž .
Ž .
35 4
C 27
1751 14
4684 5
Ž
.
Ž
Ž
Ž
Ž .
Ž .
44 4
C 28
1871 16
4152 5
Ž
Ž
.
.
.
.
.
.
Ž
Ž .
Ž .
34 4
C 29
3903 16
4058 5
Ž
Ž
Ž
Ž .
Ž .
C 30
4652 15
3859 4
22 3
Ž .
38 4
Ž
Ž
Ž
Ž .
C 31
4272 16
3967 5
Ž
.
Ž
Ž
Ž
Ž .
Ž .
43 4
C 32
3143 17
4280 6
1
q
Ž
.
Ž
. Ž
.
Ž
.
mrz % 331 100
M
Ž
Ž
Ž
Ž .
Ž .
50 5
C 33
2409 15
4494 6
Ž
.
Ž
.
Ž
Ž
Ž
Ž
2745 16
Ž .
4388 5
Ž .
49 4
C 34
.
Ž
.
Ž
.
Cpunsubst , 4.43 m, 2H, Cpsubst , 5.28 s, 2H, CH2 ,
U
is defined as one third of the trace of the orthogonalized Uij
tensor. Due to the poor quality of the available single crystal only the
eq
Ž
6.79y8.32 m, 25H, benzimidazole and tetraphenylbo-
13
.
Ž
.
Ž
.
Ž
.
,
rate . C NMR CD3CN : d 34.7 CH3 , 48.6 CH2
Ž Ž .
Ž .
Ž .
Ž .
Ž .
Ž .
Ž
.
Ž .
atoms Fe 1 , Fe 2 , W 1 , N 1 , N 2 , and carbons C 11 –C 23
could be refined anisotropically.
Ž
.
Ž
.
Ž
.
70.6 Cpunsubst , 71.1 Cpsubst , 71.3 Cpsubst , 80.1 C 1

(
)
56
B. Bildstein et al.rJournal of Organometallic Chemistry 552 1998 45–61
Table 6
w
x
Ž
.
iodide 51–56 and 0.2 g 1.7 mmol benzimidazole
4
Ž
.
Atomic coordinates 10 and equivalent isotropic displacement pa-
rameters pm =10
w
Ž
.
x
0.16 g 2.4 mmol imidazole, respectively in 10 ml
2
y1
Ž
.
for 11
DMF was refluxed for 4 h. The brown solutions were
hydrolized with 100 ml H2O and extracted with five
portions of ether. The combined organic layers were
washed with three portions of H2O, dried with Na2 SO4,
and evaporated to dryness on a rotary evaporator, yield-
ing 0.582 g 0.9 mmol, 53.6% 3a-iodide and 0.654 g
47% 3b-iodide, respectively. Conversion of the 3a-
iodide into 3a-tetraphenylborate: a solution of the iodide
0.371 g, 0.57 mmol in methanol was added to a
solution of NaB C6 H5
methanol, the resulting 3a-tetraphenylborate was fil-
tered off, washed with three portions of methanol, and
dried in vacuo, yielding 412 mg 85% 3a-tetraphenyl-
borate.
Data for 3a-iodide: yellow crystals, m.p. 1248C, dec.
Anal. Found: C, 54.18; H, 4.23. C29 H27 Fe2 IN2. Calcd.:
C, 54.24; H, 4.24%. IR KBr : cm
1559s, 1495s, 1458w, 1329w, 1265w, 1238s, 1171m,
1106s, 1040m, 1028m, 1001s, 820s, 750s, 501s, 482s.
MS FAB : mrz % 516 48
x
y
z
U
eq
Ž .
Pd 1
Ž .
22 1
0
0
5000
5673 1
6947 1
1086 1
5217 4
3790 4
6323 6
6895 7
7841 6
7856 6
6914 7
5862 5
6405 6
7355 6
7415 5
6488 5
6221 5
4638 5
2955 5
3829 5
4736 5
5035 5
4379 6
Ž .
Ž .
1707 1
Ž .
Ž .
Ž .
37 1
I 1
y2367 1
Ž .
Ž .
Ž .
Ž .
3507 1
2271 1
1015 5
798 5
4211 8
5018 8
4241 9
2915 9
2913 8
3498 7
4366 8
3599 8
2256 8
2194 7
933 7
676 6
538 7
1198 6
1329 6
1705 7
1924 8
1792 8
1419 7
1718 7
3033 8
3813 8
3001 10
1684 8
Ž .
Ž .
29 1
Fe 1
y490 1
483 1
Ž .
Ž .
Ž .
Ž .
Ž .
31 1
Fe 2
Ž
.
Ž .
Ž .
Ž .
Ž .
22 1
N 1
1994 5
Ž .
Ž .
Ž .
Ž .
Ž .
25 1
Ž
.
N 2
2213 6
Ž .
Ž .
Ž .
Ž .
Ž .
44 2
C 1
y2197 8
Ž .
Ž .
Ž .
Ž .
Ž .
48 2
C 2
y2301 8
Ž
.
Ž .
Ž .
y2111 8
Ž .
Ž .
Ž .
48 2
C 3
Ž
.
Ž
.
0.39 g, 0.87 mmol in
4
Ž .
Ž .
Ž .
Ž .
Ž .
46 2
C 4
y1879 9
Ž .
Ž .
y1940 8
Ž .
Ž .
Ž .
44 2
C 5
Ž .
Ž .
Ž .
Ž .
Ž .
Ž .
36 2
C 6
965 8
856 9
Ž .
Ž .
Ž .
Ž .
42 2
C 7
Ž
.
Ž .
Ž .
Ž .
Ž .
Ž .
42 2
C 8
1083 8
Ž .
C 10
Ž .
Ž .
Ž .
Ž .
36 2
C 9
Ž
1338 8
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Ž .
Ž .
Ž .
Ž .
26 2
1259 7
Ž
Ž .
Ž .
Ž .
Ž .
26 2
C 11
1538 7
y1
Ž
Ž .
Ž .
Ž .
Ž .
23 2
Ž
.
C 12
1479 7
3064m, 1615m,
Ž
Ž .
Ž .
Ž .
Ž .
32 2
C 13
1966 8
Ž
Ž .
Ž .
Ž .
Ž .
25 2
C 14
3210 7
Ž
Ž .
Ž .
Ž .
Ž .
24 2
C 15
3077 7
q
Ž
.
Ž
.
Ž
. Ž
.
of cationq2H ,
M
Ž
Ž .
Ž .
Ž .
Ž .
30 2
C 16
3921 7
Ž
Ž .
Ž .
Ž .
Ž .
41 2
C 17
4926 8
Ž
Ž .
Ž .
Ž .
Ž .
41 2
C 18
5062 8
Ž .
3452 6
Ž .
Table 7
Ž
Ž .
Ž .
C 19
4205 8
3156 5
34 2
Ž .
32 2
39 2
Ž .
46 2
52 2
Ž .
41 2
45 2
45 2
53 2
Ž .
45 2
49 2
125 6
108 1
Ž .
154 2
Ž .
312 25
107 3
121 4
4
Ž
.
Atomic coordinates 10 and equivalent isotropic displacement pa-
Ž
Ž .
1752 8
Ž .
Ž .
C 20
2080 5
2028 5
2
y1
Ž
.
rameters pm =10
for 13
Ž
Ž .
Ž .
Ž .
Ž .
C 21
829 9
Ž
Ž
.
Ž .
Ž .
C 22
939 10
1084 6
Ž .
x
y
z
U
eq
Ž
Ž
.
Ž
.
.
Ž .
C 23
1942 10
Ž .
2458 8
553 6
Ž .
Hg 1
I 1
Ž .
Ž .
3827 1
Ž .
4239 1
2770 1
5764 1
1146 1
4096 4
5417 4
606 7
Ž .
35 1
y170 1
Ž
Ž .
Ž .
C 24
1167 6
1431 6
Ž .
Ž .
y1757 1
Ž .
Ž .
Ž .
46 1
4946 1
Ž
Ž .
Ž .
Ž .
Ž .
C 25
y311 9
871 9
Ž .
Ž .
Ž .
Ž .
Ž .
31 1
I 2
y2730 1
4920 1
Ž
Ž .
Ž .
Ž .
Ž .
C 26
y1283 8
2110 9
Ž .
1515 6
Ž .
Ž .
Ž .
3365 2
Ž .
Ž .
Ž .
28 1
Fe 1
1884 1
Ž
Ž .
Ž .
C 27
y1334 9
3045 9
608 7
Ž .
Ž .
Ž .
Ž .
Ž .
22 2
N 1
1620 8
1091 5
Ž
Ž .
Ž .
Ž .
C 28
y371 9
2358 9
1027 9
2638 20
3539 4
920 5
6185 22
6218 11
5213 12
y24 6
Ž .
Ž .
Ž .
Ž .
Ž .
26 2
N 2
1705 9
1459 5
Ž
Ž
.
Ž .
Ž .
482 6
Ž .
Ž .
Ž .
C 29
241 10
Ž .
Ž
.
Ž .
Ž .
Ž .
51 3
C 1
1186 15
3114 9
Ž
Ž
.
Ž
Ž .
139 11
C 30
Ž .
y4160 18
Ž .
Ž
.
.
.
Ž
.
.
Ž .
Ž .
57 3
C 2
2838 17
2855 11
y59 7
Ž .
Ž .
Ž .
Cl 1
y5139 4
901 3
Ž .
Ž
Ž
Ž .
y158 6
Ž .
54 3
C 3
3402 15
1678 10
Ž .
Ž .
Ž .
Ž .
Cl 2
y3768 4
612 4
Ž .
Ž
Ž .
Ž .
Ž .
Ž .
54 3
C 4
2133 17
1122 9
456 7
Ž
.
Ž
.
.
.
Ž
.
.
.
Ž
.
.
C 31
y4488 20
3144 35
Ž .
Ž .
Ž
.
Ž
.
Ž .
59 3
C 5
751 14
2014 13
924 6
2234 5
1603 6
1472 6
2031 5
2505 5
3134 5
4623 6
6193 6
5424 5
4569 5
4333 5
4986 6
5859 6
6089 5
7723 5
Ž
.
.
.
.
Ž
Ž
Ž .
Ž .
Ž .
Cl 3A
y4747 10
3857 4
Ž .
Ž
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Ž .
Ž .
Ž .
29 2
C 6
3684 11
2551 7
Ž
Ž
Ž
Ž
Cl 4A
y4270 11
2298 10
2034 5
2128 7
Ž .
Ž
Ž .
Ž .
Ž .
35 2
C 7
5423 12
2334 8
Ž
Ž .
Ž .
Ž .
Cl 3B
y4633 5
7914 5
5187 10
82 2
Ž .
Ž .
Ž
Ž .
Ž .
Ž .
38 2
C 8
5995 12
1112 9
Ž
Ž .
Ž
.
Ž .
Cl 4B
y3504 8
85 2
Ž .
C 10
Ž
Ž .
Ž .
Ž .
30 2
C 9
Ž
4653 12
539 7
.
.
.
.
.
.
.
.
.
.
Ž
Ž .
Ž .
Ž .
23 2
3194 10
1426 7
U
is defined as one third of the trace of the orthogonalized Uij
eq
Ž
Ž
Ž .
Ž .
Ž .
27 2
C 11
1440 11
1253 7
tensor. Symmetry transformations used to generate equivalent atoms:
yx, yy, yzq1.
Ž
Ž
Ž .
Ž .
Ž .
25 2
C 12
1177 11
1975 7
Ž
Ž
Ž .
Ž .
Ž .
35 2
C 13
1524 13
2103 8
Ž
Ž
Ž .
Ž .
Ž .
19 2
C 14
2455 10
216 6
Ž
.
Ž
.
4.22 m, 7H, Cpsubst and Cpunsubst , 4.43 m, 2H, Cpsubst ,
Ž
Ž
Ž .
Ž .
Ž .
23 2
C 15
2408 10
y10 7
Ž
.
Ž
.
Ž
5.15 s, 2H, CH2 , 7.62 s, 1H, imidazole , 7.71 s, 1H,
Ž
Ž
Ž .
Ž .
Ž .
27 2
C 16
3045 11
y1172 7
13
.
Ž
.
Ž
Ž
Ž
Ž .
Ž .
Ž .
imidazole , 9.05 s, 1H, imidazole . C NMR DMSO-
C 17
3740 12
y2059 7
32 2
Ž .
35 2
Ž
Ž
Ž .
y1813 7
Ž .
C 18
3786 12
.
Ž
.
Ž
.
Ž
.
d6 : d 35.9 CH3 , 48.4 CH2 , 68.8 Cpunsubst , 68.9
Ž Ž .
Ž
Ž
Ž .
Ž .
Ž .
27 2
C 19
3134 11
y670 7
Ž
.
Ž
.
.
Cpsubst , 69.0 Cpsubst , 80.9 C 1 of Cpsubst ; 122.0,
Ž .
Ž
Ž .
1543 7
Ž .
Ž .
57 2
O 1
y2501 10
Ž
.
123.6, 135.8 imidazole .
Ž .
Ž
Ž .
Ž .
Ž .
41 2
N 3
y2473 11
3055 7
8447 5
7908 6
8624 8
Ž .
8885 9
Ž
.
.
.
Ž
Ž .
Ž .
Ž .
43 2
C 20
y3112 14
2592 9
(
)
4.5. 1,3-Bis ferrocenylmethyl benzimidazolium iodide
Ž
Ž
y3288 18
Ž .
Ž .
Ž .
77 4
C 21
4293 9
a n d te tr a p h e n y lb o r a te 3 a a n d 1 ,3 -
Ž
Ž .
y898 21
Ž
.
Ž .
87 4
C 22
2342 11
(
)
bis ferrocenylmethyl imidazolium iodide 3b
U
is defined as one third of the trace of the orthogonalized Uij
tensor. Symmetry transformations used to generate equivalent atoms:
yx, yy q1, yzq1.
eq
Ž
.
w
Ž
.
A mixture of 1.43 g 3.7 mmol 2.9 g 5.2 mmol ,
respectively ferrocenylmethyl trimethyl ammonium
x
Ž
.

(
)
B. Bildstein et al.rJournal of Organometallic Chemistry 552 1998 45–61
57
1
q
Ž
. Ž
.
Ž
.
316 100
M
of cation-FcCH2 . H NMR CDCl3 : d
with three portions of methanol, and dried in vacuo,
yielding 310 mg 90% 5-tetraphenylborate.
Ž
.
Ž
.
Ž
Ž
.
4.19 m, 4H, Cpsubst , 4.25 s, 10H, Cpunsubst , 4.54 m,
4H, Cpsubst , 5.56 s, 4H, CH2 , 7.55–10.98 m, 5H,
.
Ž
.
Ž
Data for 4: yellow crystals, m.p. 1318C. Anal. Found:
13
.
.
Ž
.
Ž
.
benzimidazole . C NMR DMSO-d6 : d 46.4 CH2 ,
Ž Ž .
C, 69.13; H, 5.51. C19 H18 FeN2. Calcd.: C, 69.11; H,
y1
Ž
Ž
.
Ž
.
Ž
.
68.9 Cpunsubst , 69.0 Cpsubst , 69.5 Cpsubst , 80.2 C 1
5.49%. IR KBr : cm
3091w, 2930w, 1501s, 1458s,
.
Ž
.
of Cpsubst ; 114.0, 126.8, 130.7, 140.9 benzimidazole .
Data for 3a-tetraphenylborate: yellow crystals, m.p.
120–1228C. Anal. Found: C, 76.15; H, 5.65.
C53 H47 Fe2 BN2. Calcd.: C, 76.29; H, 5.68%. IR KBr :
cmy1 3056m, 2984w, 1580w, 1560s, 1479s, 1425m,
1238w, 1167m, 1107m, 1041w, 1030m, 1001s, 823s,
1358m, 1283m, 1254m, 1223s, 1105m, 1040m, 1001w,
Ž
818m, 802m, 766w, 746s, 499m, 488m, 428w. MS EI,
q
q
.
Ž
.
Ž
. Ž
.
Ž
. Ž
.
70 eV : mrz % 330 100
M
Ž
, 265 38 M –Cp ,
199 39 FcCH2 . H NMR CDCl3 : d 2.85 t, 2H,
CH2 , 3.89 m, 2H, Cpsubst , 4.05 m, 2H, Cpsubst , 4.06
s, 5H, Cpunsubst , 4.21 t, 2H, CH2 , 7.23–7.80 m, 5H,
benzimidazole . C NMR CDCl3 : d 30.5 CH2 ,
46.5 CH2 , 68.0 Cpsubst , 68.3 Cpunsubst , 68.5
Cpsubst , 83.8 C 1 of Cpsubst ; 109.5, 120.4, 122.0
1
Ž
.
Ž
. Ž
.
.
Ž
.
Ž
.
Ž
.
.
Ž
.
Ž
Ž
13
Ž
.
Ž
Ž
.
.
Ž
.
.
Ž
.
.
735s, 706s, 611s, 499s, 482s. MS FAB : mrz %
1
q
Ž
. Ž
.
Ž
.
.
Ž
.
Ž
Ž
516 100
M
of cation . H NMR CDCl3 : d 4.38 m,
.
Ž
Ž
Ž
.
Ž Ž .
.
18H, Cpsubst and Cpunsubst , 4.80 s, 4H, CH2 , 7.07–7.74
m, 25H, benzimidazole and tetraphenylborate . 13C
Ž
.
.
.
benzimidazole .
Ž
.
Ž
.
Ž
NMR CDCl3 : d 47.7 CH2 , 69.2 Cpunsubst , 69.4
Data for 5-bromide: yellow crystals, m.p. 2108C.
Ž
.
Ž
.
Ž Ž .
.
Cpsubst , 69.5 Cpsubst , 78.4 C 1 of Cpsubst ; 113.3,
Anal. Found: C, 59.79; H, 4.89. C31H30 BrFe2 N2.
y1
Ž
Ž
.
122.1, 126.0, 126.9, 130.7, 134.5, 136.1, 139.3 be-
Calcd.: C, 59.84; H, 4.86%. IR KBr : cm
3089w,
.
Ž
.
nzimidazole and tetraphenylborate . CV CH3CN; 208C
2927w, 1616m, 1489s, 1456m, 1435m, 1352w, 1175w,
1105s, 1043m, 1024m, 1001w, 821s, 810s, 762s, 484s.
w x
V : 0.58.
1
q
Ž
.
Ž
.
Ž
. Ž
.
Data for 3b-iodide: yellow crystals, m.p. 1998C, dec.
Anal. Found: C, 50.76; H, 4.25. C25 H25Fe2 IN2. Calcd.:
C, 50.71; H, 4.26%. IR KBr : cm
MS FAB : mrz % 543 100
M
of cation . H NMR
Ž
.
Ž
.
Ž
.
CDCl3 : d 2.90 t, 4H, CH2 , 4.04 br s, 8H, Cpsubst
,
y1
Ž
.
Ž
.
Ž
.
3075w, 1626m,
4.13 s, 10H, Cpunsubst , 4.55 t, 4H, CH2 , 7.63–9.60
13
Ž
Ž
Ž
.
Ž
.
1557s, 1443w, 1410w, 1337w, 1238m, 1142s, 1105s,
1041s, 1028m, 1001m, 820s, 773w, 625w, 503s, 482s.
m, 5H, benzimidazole . C NMR CDCl3 : d 29.2
.
Ž
.
Ž
.
Ž
.
CH2 , 47.6 CH2 , 67.7 Cpsubst , 68.3 Cpsubst , 68.6
Ž Ž .
1
q
Ž
.
Ž
.
Ž
. Ž
.
.
.
MS FAB : mrz % 465 100
M
of cation . H NMR
Cpunsubst , 83.2 C 1 of Cpsubst ; 113.8, 126.6, 130.9,
Ž
.
Ž
.
Ž
Ž
.
CDCl3 : d 4.29 m, 4H, Cpsubst , 4.30 s, 10H,
142.0 benzimidazole .
.
Ž
.
Ž
.
Ž
.
Cpunsubst , 4.51 m, 4H, Cpsubst , 5.39 s, 4H, CH2 ,
Data for 5-tetraphenylborate: yellow crystals, m.p.
7.24 s, 2H, imidazole , 10.00 s, 1H, imidazole . 13C
Ž
.
.
1928C. Anal. Found: C, 76.71; H, 5.82. C55 H50 Fe2 BN2.
y1
Ž
.
Ž
Ž
.
Ž
.
NMR CDCl3 : d 49.9 CH2 , 69.1 Cpunsubst , 69.6
Ž Ž .
Calcd.: C, 76.68; H, 5.85%. IR KBr : cm
3056m,
Ž
.
Ž
.
.
Cpsubst , 69.7 Cpsubst , 78.4 C 1 of Cpsubst ; 121.0,
2984w, 1557w, 1478s, 1456s, 1425m, 1107m, 1040w,
1032w, 1001m, 831m, 820s, 808m, 752s, 737s, 717s,
Ž
.
Ž
134.7 imidazole . X-ray structure Tables 1 and 3; Fig.
q
.
Ž
.
Ž
.
Ž
. Ž
2 : single crystals were obtained by slow diffusion of
hexane into a dichloromethane solution of 3b-iodide.
613s, 499s, 482s. MS FAB : mrz % 543 100
M
.
of
1
.
Ž
.
Ž
cation . H NMR CD3CN : d 2.88 t, 4H, CH2 , 3.93
m, 4H, Cpsubst , 4.06 m, 4H, Cpsubst , 4.11 s, 10H,
Ž
.
Ž
Ž
.
Ž
(
)
.
.
Ž
4.6. N- ferrocenylethyl benzimidazole 4 and 1,3-
bis ferrocenylethyl benzimidazolium bromide and te-
traphenylborate 5
Cpunsubst , 4.39 t, 4H, CH2 , 6.78–8.28 m, 25H, benz-
13
(
)
.
Ž
.
imidazole and tetraphenylborate . C NMR CDCl3 : d
Ž
Ž
.
Ž
.
Ž
.
Ž
.
31.0 CH2 , 50.0 CH2 , 69.6 Cpsubst , 70.0 Cpsubst ,
.
Ž Ž .
.
70.2 Cpunsubst , not observed: C 1 of Cpsubst ; 115.1,
Ž
.
Ž
A THF solution of 0.887 g 7.5 mmol benzimida-
118.9, 123.4, 127.16, 127.22, 128.4, 137.3, 142.0 be-
.
Ž
.
zole was cooled to y808C and lithiated with 3.75 ml
nzimidazole and tetraphenylborate . CV CH3CN; 208C
Ž
.
Ž
w x
V : 0.45.
7.5 mmol n-butyl lithium 2.0 molar solution in hex-
.
ane . After the mixture was allowed to warm to room
. Ž
Ž
.
(
)
temperature, 2 g 6.8 mmol 2-bromoethyl ferrocene
4.7. 1- Ferrocenylmethyl -3-methyl-benzimidazoline-2-
w
x
57–63 was added in one portion and the mixture was
refluxed overnight. Aqueous work-up and chromatogra-
phy Al2O3, ethyl acetate as eluent yielded 1.286 g
3.9 mmol, 57% 4. Conversion to 5-bromide: a mixture
of 0.794 g 2.4 mmol 4, 0.8 g 2.7 mmol 2-
bromoethyl ferrocene, and 10 ml acetonitrile was re-
fluxed for 4 days. Aqueous work-up yielded 1.33 g 2.1
mmol, 89% 5-bromide. Conversion of 5-bromide to
5-tetraphenylborate: a solution of the bromide 0.250 g,
thione 6
Ž
.
Ž
A Schlenk vessel was charged with 0.19 g 0.4
Ž
.
.
mmol 2a and 20 ml THF. The mixture was cooled to
Ž
.
Ž
. Ž
Ž
y808C and lithiated with n-butyl lithium 0.2 ml of a
.
.
2.0 molar hexane solution, 0.4 mmol . After addition of
Ž
Ž
.
0.3 g 1.2 mmol sulfur and stirring at room temperature
for 3 h. the mixture was filtered through a short plug of
Al2O3 and worked-up in the usual manner, yielding 80
.
Ž
.
Ž
.
0.40 mmol in methanol was added to a solution of
0.21 g, 0.60 mmol in methanol, the
resulting 5-tetraphenylborate was filtered off, washed
mg 0.2 mmol, 53% 6.
Ž
.
Ž
.
NaB C6 H5
Yellow crystals, m.p. 1158C, dec. Anal. Found: C,
58.88; H, 5.60. C16 H18 FeN2 S. Calcd.: C, 58.91; H,
4

(
)
58
B. Bildstein et al.rJournal of Organometallic Chemistry 552 1998 45–61
y1
Ž
.
Ž
.
5.56%. IR KBr : cm
3073w, 2936w, 1692s, 1672s,
structure Tables 1 and 5; Fig. 4 : single crystals were
obtained from dichloromethanerhexane.
1491m, 1439m, 1406s, 1387m, 1350s, 1337m, 1317w,
1169s, 1105w, 1020s, 823s, 806s, 742s, 503s, 484s.
Data for 8: yellow crystals, m.p. 1978C. Anal. Found:
C, 43.10; H, 2.50. C23 H16 FeN2O5W. Calcd.: C, 43.16;
H, 2.52%. IR KBr : cm 2068s nC 5O , 1966s nC 5O ,
q
q
Ž
.
Ž
.
.
Ž
. Ž
.
Ž
. Ž
MS EI, 70 eV : mrz % 362 46
M
, 348 63 M –
q
q
y1
.
Ž
. Ž
.
Ž
. Ž
.
Ž .
Ž
.
.
Ž
.
Ž
Ž
.
CH3 , 330 11 M –S , 297 35 M –Cp , 282 8
q
q
Ž
Ž
Ž
.
Ž
.
Ž
.
Ž
Ž
.
.
M –CH 3 –Cp , 265 23
M –Cp–S , 199 100
1917s nC 5O , 1896s nC 5O , 1883s nC 5O , 1516s,
1460s, 1385w, 1263w, 1240w, 1167w, 1040m, 1028m,
1005m, 823m, 744s, 603s, 580s, 505w, 482w.
1
.
Ž
.
Ž
.
FcCH2 . H NMR DMSO-d6 : d 3.75 s, 3H, CH3 ,
4.10 m, 2H, Cpsubst , 4.22 s, 5H, Cpunsubst , 4.47 m,
Ž
.
Ž
.
Ž
q
q
.
Ž
.
Ž
Ž
Ž
.
Ž
.
Ž
. Ž
.
Ž
. Ž
.
2H, Cpsubst , 5.31 s, 2H, CH2 , 7.00–7.22 m, 4H,
MS FAB : mrz % 640 100
M
, 613 10 M –CO ,
13
584 40 M –2 CO , 553 8 M –3 CO . 1H NMR
q
q
.
Ž
.
Ž
.
.
. Ž
.
Ž . Ž
.
benzimidazole . C NMR DMSO-d6 : d 31.2 CH3 ,
Ž
.
Ž
.
Ž
Ž
.
Ž
.
Ž
.
.
44.2 CH2 , 68.5 Cpsubst , 68.8 Cpunsubst , 69.7
Ž Ž .
CDCl3 : d 4.20 s, 5H, Cpunsubst , 4.25 m, 2H, Cpsubst ,
4.28 m, 2H, Cpsubst , 5.12 s, 2H, CH2 , 7.44–8.06 m,
5H, benzimidazole . C NMR CDCl3 : d 45.8 CH2 ,
69.0 Cpunsubst , 69.4 Cpsubst ; 110.6, 120.8, 124.3,
124.5, 147.3 benzimidazole ; 198.3 C5O .
Data for 2,3-dihydro-2-butyl-1,3-bis ferro-
cenylmethyl benzimidazole: yellow crystals, m.p. 147–
1518C. Anal. Found: C, 69.23; H, 6.33. C33 H36 Fe2 N2.
Calcd.: C, 69.25; H, 6.34%. IR KBr : cm
2921m, 1601w, 1493s, 1387m, 1373w, 1333w, 1302w,
Ž
.
.
Ž
.
Ž
Ž
Cpsubst , 82.1 C 1 of Cpsubst ; 108.8, 109.3, 121.1,
13
Ž
.
Ž
.
Ž
.
Ž
.
.
Ž
.
122.7 benzimidazole ; 198.0 C5S . CV CH3CN;
.
w x
Ž
Ž
.
Ž
208C V : 0.47. X-ray structure Tables 1 and 4; Fig.
3 : single crystals w ere obtained from
dichloromethanerhexane.
.
Ž
.
Ž
.
Ž
.
[
(
))
4.8. 1,3-Di ferrocenylmethyl benzimidazoline-2-
y1
]
)
( )
[ (
Ž
.
ylidene pentacarbonyl tungsten 0 7, 1- ferrocenyl-
( )
3093w,
]
methyl benzimidazole pentacarbonyl tungsten 0 8, and
[
(
))
]
1,3-di ferrocenylethyl benzimidazoline-2-ylidene pen-
1265m, 1246m, 1105s, 1026m, 999w, 820s, 764m, 723s,
q
( )
Ž
.
Ž
.
Ž
. Ž
.
Ž
.
tacarbonyl tungsten 0 9
493s. MS EI, 70 eV : mrz % 573 18
M
, 516 24
q
q
Ž
Ž
.
Ž
.
Ž
.
Ž
.
M –C 41H 9
,
373 20
M –FcCH 3
,
199 100
Ž
.
.
Ž
.
Ž
A Schlenk vessel was charged with 0.2 g 0.3 mmol
3a-iodide and 70 ml THF. The mixture was cooled to
FcCH2 . H NMR CDCl3 : d 0.80–1.24 m, 9H, H3C-
.
Ž
.
Ž
CH2-CH2-CH2 , 4.08 m, 4H, Cpsubst , 4.10 br s, 14H,
Cpunsubst and Cpsubst , 4.70 s, 4H, CH2 , 6.33–6.53 m,
4H, benzimidazole . C NMR CDCl3 : d 14.2 CH3 ,
Ž
.
Ž
.
Ž
y808C and lithiated with n-butyl lithium 0.16 ml of a
13
.
.
Ž
Ž
.
Ž
.
2.0 molar hexane solution, 0.3 mmol . While this solu-
Ž
Ž
.
.
.
Ž
.
Ž
.
tion was allowed to warm to room temperature, a
second Schlenk vessel was charged with 0.5 g 1.4
mmol W CO and 30 ml THF, and photolyzed with a
150W high pressure mercury lamp. The resulting solu-
tion of W CO PTHF was added to the benzimidazo-
line-2-ylidene derived from 3a. After stirring at room
temperature for 30 min the mixture was worked-up and
chromatographed, yielding 18 mg 0.02 mmol, 6.9% 7,
17 mg 0.02 mmol, 8.5% 8, and 11 mg 0.02 mmol,
6.2% 2,3-dihydro-2-butyl-1,3-bis ferrocenylmethyl be-
nzimidazole. Analogously, metal carbonyl complex 9
was prepared from 0.2 g 0.3 mmol 5-iodide by depro-
tonation with butyl lithium and subsequent reaction with
22.9 CH2 , 24.2 CH2 , 31.3 CH2 , 46.8 CH2
Ž Ž .
,
Ž
Ž
.
Ž
.
67.7 Cpsubst , 68.1 Cpsubst , 68.5 Cpunsubst , 83.4 C 1
.
Ž
.
.
Ž
.
of Cpsubst ; 105.4, 118.0, 141.5 benzimidazole .
6
Data for 9: yellow crystals, m.p. 1288C, dec. Anal.
Found: C, 49.87; H, 3.46. C36 H30 Fe2 N2O5W. Calcd.:
C, 49.92; H, 3.49%. IR KBr : cm
2062s nC 5O , 1977s nC 5O , 1950s nC 5O , 1925s
Ž
.
5
y1
Ž
.
.
2963w, 2929w,
Ž
.
.
Ž
Ž
.
Ž
.
Ž
nC 5O , 1261s, 1134m, 1107s, 1030s, 1001s, 802s,
Ž
.
Ž
750m, 740m, 603s, 594s, 578m, 499m, 482m.
1
q
.
Ž
.
Ž
.
Ž
.
MS FAB : M not observed. H NMR CDCl3 : d
Ž
.
Ž
.
Ž
2.95 m, 4H, CH2 , 4.14 s, 10H, Cpunsubst , 4.16 m,
4H, Cpsubst , 4.22 m, 4H, Cpsubst , 4.65 m, 4H, CH2 ,
7.37 br s, 4H, benzimidazole . C NMR CDCl3 : d
Ž
.
.
Ž
.
Ž
.
13
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
photochemically generated W CO PTHF, affording 57
31.6 CH2 , 51.7 CH2 , 68.3 Cpsubst , 68.4 Cpsubst
Ž Ž .
,
5
Ž
.
Ž
.
.
mg 0.07 mmol, 20.5% 9.
68.7 Cpunsubst , 83.5 C 1 of Cpsubst ; 110.9, 123.4,
Ž
.
Ž
.
Ž
Data for 7: yellow crystals, m.p. 163–1658C. Anal.
Found: C, 48.69; H, 3.14. C34 H26 Fe2 N2O5W. Calcd.:
C, 48.72; H, 3.13%. IR KBr : cm
2060s nC 5O , 1971s nC 5O , 1935s nC 5O , 1479s,
1337s, 1306s, 1161m, 1105s, 1041s, 1028m, 1001s,
825s, 740s, 607s, 592m, 578s, 501s, 486m. MS FAB :
134.4 benzimidazole ; 196.4 C5O , 197.7 carbene-
C , 198.9 C5O , 200.1 C5O . CV CH3CN; 208C
V : 0.43.
.
Ž
.
Ž
.
Ž
.
y1
Ž
.
.
w x
3106w, 2929w,
Ž
.
Ž
Ž
.
( )
4.9. Palladium II complexes 10 and 11
Ž
.
q
q
Ž
.
Ž
. Ž
.
Ž
. Ž .
.
Ž
Ž
.
x
w
mrz % 838 100
M
, 755 12 M –3 CO , 696 34
A mixture of 0.24 g 0.5 mmol 2a-iodide 0.3 g
1
q
Ž
.
Ž
.
Ž
.
Ž
.
Ž
M –5 CO ,. H NMR CDCl3 : d 4.14 m, 4H, Cpsubst
,
0.47 mmol 3a-iodide, respectively and 59 mg 0.25
Ž
.
Ž
.
Ž
.
Ž .
4.23 s, 10H, Cpunsubst , 4.36 m, 4H, Cpsubst , 5.64 s,
mmol Pd II acetate was refluxed in THF for 30 min.
Solvent was removed in vacuo and the solid residue was
washed with three portions of ether. The crude product
was dissolved in dichloromethane and crystallized by
4H, CH2 , 7.03–7.36 m, 4H, benzimidazole . 13C NMR
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
CDCl3 : d 52.0 CH2 , 68.4 Cpsubst , 69.2 Cpunsubst
Ž Ž .
,
Ž
.
.
70.1 Cpsubst , 81.6 C 1 of Cpsubst ; 111.9, 122.7,
Ž
.
Ž
.
Ž
Ž
.
134.7 benzimidazole ; 191.6 C5O , 197.8 carbene-
w x
addition of hexane, yielding 178 mg 0.17 mmol, 67%
10 or 63 mg 0.05 mmol, 19.4% 11, respectively.
.
Ž
.
Ž
.
Ž
.
C , 200.4 C5O . CV CH3CN; 208C V : 0.53. X-ray

(
)
B. Bildstein et al.rJournal of Organometallic Chemistry 552 1998 45–61
59
1
w
Ž
Ž
.
Data for trans-bis 1-ferrocenylmethyl-3-methyl-be-
1-ferrocenylmethyl-3-methyl-benzimidazole . H NMR
x
Ž .
.
Ž
.
Ž
.
nzimidazoline-2-ylidene -diiodopalladium II 10: yellow
crystals, m.p. not observed up to 3308C. Anal. Found:
DMF-d7 : d 4.25 6H, s, CH3 , 4.29 10H, s, Cpunsubst ,
4.33–4.80 8H, m, Cpsubst , 5.89 4H, s, CH2 , 7.51–8.0
8H, m, benzimidazole . C NMR DMF-d7 : d 30.04
CH3 ; 47.37, 48.03 CH2 ; 69.06, 69.43, 69.63, 70.42,
70.83 Cpsubst and Cpunsubst ; 112.62, 113.09, 113.44,
113.83, 114.11, 114.33, 125.41, 125.85, 127.28, 142.94
Ž
.
Ž
.
13
Ž
Ž
.
Ž
.
C, 44.67; H, 3.59. C38 H36 Fe2 I2 N4 Pd. Calcd.: C, 44.72;
H, 3.56%. IR KBr : cm
1460m, 1443s, 1404m, 1391s, 1177w, 1107m, 1043m,
y1
Ž
.
.
Ž
.
3081w, 2929w, 1479s,
Ž
.
Ž
.
1024s, 1001s, 818s, 802s, 750s, 501s, 482s. MS FAB :
q
Ž
.
Ž
. Ž
.
Ž
.
mrz % 1020 100
M . Due to insufficient solubility
benzimidazole .
w
andror decomposition in solution no NMR data could
Data for bis 1-ferrocenylmethyl-3-methyl-benzimi-
X
x
Ž .
be obtained.
dazoline-2-ylidene diiodo-mm -diiodo-dimercury II 13:
yellow crystals, m.p. 2008C, dec. Anal. Found: C, 29.02;
H, 2.35. C38 H36 Fe2yH1g2 I4 N4. Calcd.: C, 29.09; H,
w
Ž
.
Data for bis 1,3-di ferrocenylmethyl benzimidazo-
line-2-ylidene -diiodopalladium II 11: yellow crystals,
m.p. not observed up to 3308C. Anal. Found: C, 50.10;
H, 3.80. C58 H52 Fe4 I2 N4 Pd. Calcd.: C, 50.16; H, 3.77%.
IR KBr : cm 3093w, 2925w, 1616m, 1514w, 1478s,
1443m, 1410s, 1393s, 1366m, 1339m, 1171w, 1150s,
x
Ž .
Ž
.
2.31%. IR KBr : cm
3075w, 2944w, 1481s, 1456s,
1410s, 1395s, 1346m, 1335s, 1261m, 1103m, 1016m,
816m, 798s, 789m, 766w, 754s, 737s, 499s, 482m.
y1
Ž
.
q
q
Ž
.
Ž
.
Ž . Ž
.
Ž
. Ž
MS ESI : mrz % 1446 4 M qH , 988 100 M –
1
q
Ž
.
.
Ž
. Ž
.
Ž
1041m, 1024m, 1001m, 820s, 742s, 499s. MS FAB :
HgI2 , 658 20 M –HgI4–FcCH2 . H NMR DMF-
mrz % 1388 30
M
, 1189 10 M –FcCH2 . 1H
q
q
Ž
.
Ž
. Ž
.
Ž
. Ž
.
Ž
.
Ž
.
d7 : d 3.49 6H, s, CH3 ; 5.71, 5.75, 5.81, 5.87, 5.95
22H, m, Cpunsubst, Cpsubst, CH2 ; 7.54–8.07 8H, m,
benzimidazole . C NMR DMF-d7 due to decompo-
sition during accumulation of the FID only a few of the
expected signals were observed : d 69.25, 69.58, 69.67,
70.67, 70.81 Cpsubst and Cpunsubst ; 113.62, 125.76
benzimidazole . X-ray structure Tables 1 and 7; Fig.
6 : single crystals were obtained from a saturated DMF
Ž
.
Ž
.
Ž
NMR CDCl3 : d 4.16, 4.21, 4.31, 4.73, 4.76 16H,
each signal: m, CH2 , 4.26 20H, s, Cpunsubst , 5.92 s,
4H, CH2 , 5.98 s, 4H, CH2 , 6.98–7.45 m, 8H,
benzimidazole . C NMR CDCl3 : d 45.7, 49.6, 50.8
13
.
Ž
.
Ž
.
Ž
. Ž
.
Ž
.
Ž
13
.
Ž
.
.
Ž
.
Ž
Ž
.
.
CH2 ; 68.3, 68.4, 69.0, 69.2, 70.7, 70.8 Cpsubst and
.
Ž Ž .
.
Ž
Ž
Cpunsubst ; 80.9, 82.3 C 1 of Cpsubst ; 110.5, 111.2,
111.8, 121.7, 122.2, 122.3, 123.2, 124.1, 134.6, 134.7,
.
Ž
.
Ž
.
144.2 benzimidazole ; 179.4 carbene-C . X-ray struc-
ture of trans–anti isomer Tables 1 and 6; Fig. 5 :
single crystals were obtained from dichloromethane.
solution at y258C.
Ž
.
w
Data for bis 1-ferrocenylmethyl-3-methyl-imidazo-
line-2-ylidene mercury II diiodide 12b: yellow crystals,
m.p. 2008C, dec. Anal. Found: C, 35.47; H, 3.21.
C30 H32 Fe2 HgI2 N4. Calcd.: C, 35.51; H, 3.18%.
IR KBr : cm 3143w, 3093m, 1634m, 1564m, 1464s,
1439m, 1412s, 1215s, 1105s, 1040m, 1026m, 1001s,
x
Ž .
( )
4.10. Mercury II complexes 12a,b, 13, 14a,b, 15
y1
Ž
Ž
.
Mixtures of azolium halogenides 2a,b, 3a,b, 5 XsI
.
or Br were refluxed for 40 min in THF with 0.5 mole
Ž .
Ž
.
Ž
.
Ž
.
equivalents of mercury II acetate: 0.2 g 0.4 mmol
818s, 754s, 733s, 505s, 484s. MS ESI : mrz %
1
q
Ž
.
Ž
.
Ž
Ž
. Ž
.
Ž
Ž
.
2a-iodider70 mg 0.2 mmol Hg OAc ; 212 mg 0.5
889 100 M q1H–I . H NMR DMF-d7 : d 3.45
.
Ž
.
2 Ž
.
Ž
.
Ž
.
Ž
Ž
mmol 2b-iodider83 mg 0.25 mmol Hg OAc ; 0.2 g
6H, s, CH3 , 4.04 2H, m, Cpsubst , 4.12 2H, m,
2
Ž
Ž
.
Ž
.
Ž
.
.
.
.
0.3 mmol 3a-iodider50 mg 0.15 mmol Hg OAc ;
Cpsubst , 4.27 10H, s, Cpunsubst , 4.49 2H, m, Cpsubst ,
4.60 2H, m, Cpsubst ; 5.60, 5.79 4H, s, CH2 ; 7.61,
7.72, 7.74, 7.85 4H, imidazole . C NMR DMF-d7 :
d 43.81 CH3 ; 55.31, 55.99 CH2 ; 74.50, 74.72, 75.27
2
Ž
.
.
Ž
.
Ž
.
228 mg 0.4 mmol 3b-iodider60 mg 0.19 mmol
13
Ž
.
Ž
.
Ž
Ž
.
Ž
.
Hg OAc ; 92 mg 0.14 mmol 5-bromider24 mg 0.07
.
2 Ž
.
Ž
.
Ž
.
mmol Hg OAc ; respectively. During this reflux pe-
2
Ž
Ž
.
riod a color change yellow-brown-tan took place. For
work-up THF was removed on a rotary evaporator, the
residues were washed with three portions of ether, and
the crude products were dissolved in dichloromethane
and crystallized by addition of a small layer of hexane,
Cpsubst and Cpunsubst ; 127.59, 128.61, 130.06, 130.50
.
imidazole .
w
Ž
.
Data for bis 1,3-di ferrocenylmethyl benzimidazo-
line-2-ylidene mercury II diiodide 14a: yellow crystals,
m.p. 1808C, dec. Anal. Found: C, 46.95; H, 3.50.
C58 H52 Fe4 HgI2 N4. Calcd.: C, 46.98; H, 3.53%.
IR KBr : cm 3094w, 2938w, 1634m, 1559s, 1476w,
1447s, 1412s, 1395w, 1319w, 1105s, 1041m, 1028m,
x
Ž .
Ž
.
Ž
resulting in: 90 mg 0.08 mmol, 37% 12a; 60 mg 0.04
y1
.
Ž
.
Ž
.
mmol, 20.7% 13; 133 mg 0.13 mmol, 56.6% 12b; 50
Ž
.
Ž
.
mg 0.03 mmol, 21.6% 14a; 72 mg 0.05 mmol, 27%
Ž
.
Ž
.
14b; 55 mg 0.04 mmol, 49% 15; respectively.
1013w, 1001s, 820s, 794s, 756m, 501s, 482s. MS ESI :
q
q
w
Ž
.
.
Ž
. Ž
.
Ž
. Ž
.
Data for bis 1-ferrocenylmethyl-3-methyl-benzimi-
mrz % 1356 15 M –I , 1287 53 M –FcCH2 ,
1
x
Ž .
Ž
Ž
.
Ž
.
dazoline-2-ylidene mercury II diiodide 12a: yellow
crystals, m.p. 2008C, dec. Anal. Found: C, 40.88; H,
3.28. C38 H36yF1e2 HgI2 N4. Calcd.: C, 40.94; H, 3.25%.
515 100 . H NMR DMF-d7 : d 4.16 4H, m, Cpsubst ,
Ž
.
Ž
.
Ž
4.23 4H, m, Cpsubst , 4.31 20H, s, Cpunsubst , 4.72 4H,
m, Cpsubst , 4.76 4H, m, Cpsubst , 5.84 8H, s, CH2 ,
7.53–8.27 8H, m, benzimidazole . C NMR DMF-
d7 : d 48.49 CH2 ; 69.36, 69.66, 70.69, 82.56 Cpsubst
.
Ž
.
Ž
.
13
Ž
.
Ž
.
Ž
Ž
IR KBr : cm 3077w, 1568w, 1481m, 1458s, 1408m,
1393m, 1377w, 1337w, 1105m, 1041w, 1016m, 1001m,
.
Ž
.
.
Ž
.
Ž
.
.
Ž
820s, 798s, 787s, 748s, 501s, 482s. MS ESI : mrz %
and Cpunsubst ; 113.9, 114.38, 125.88, 126.37 be-
q
q
Ž
. Ž
.
Ž
. Ž
.
Ž
.
987 75 M –I , 659 30 M –2I–FcCH2 , 331 100
nzimidazole .

(
)
60
B. Bildstein et al.rJournal of Organometallic Chemistry 552 1998 45–61
w
w
w
w
w
w
w
w
x
20 W.A. Herrmann, L.J. Gooßen, C. Kocher, G.R.J. Artus, Angew.
¨
w
Ž
.
Data for bis 1,3-di ferrocenylmethyl imidazoline-2-
Ž
.
Chem. 108 1996 2980.
x
Ž .
ylidene mercury II diiodide 14b: yellow crystals, m.p.
1808C, dec. Anal. Found: C, 43.39; H, 3.52.
x
21 W.A. Herrmann, L.J. Gooßen, C. Kocher, G.R.J. Artus, Angew.
¨
Ž
.
Chem. Int. Ed. Engl. 35 1996 2805.
C50 H48 Fe4 HgI2 N4. Calcd.: C, 43.43; H, 3.50%.
IR KBr : cm 3087w, 1636m, 1559s, 1464w, 1423m,
1410s, 1385w, 1238m, 1209w, 1105s, 1040s, 1026s,
x
22 W.A. Herrmann, C. Kocher, L.J. Gooßen, G.R.J. Artus, Chem.
¨
y1
Ž
.
Ž
.
Eur. J. 2 1996 1627.
x
23 W.A. Herrmann, G.M. Lobmaier, M. Elison, J. Organomet.
Ž
.
Chem. 520 1996 231.
Ž
.
1001m, 820s, 733m, 515s, 499s, 484s. MS ESI :
x
24 W.A. Herrmann, F.C. Munck, G.R.J. Artus, O. Runte, R. An-
q
q
Ž
Ž
.
.
Ž
Ž
. Ž
.
Ž . Ž
.
Ž
.
mrz % 1383 40
M
, 1254 8 M –I , 1189 23 ,
Ž
.
wander, Organometallics 16 1997 682.
¨
1
.
Ž
.
Ž
1055 41 , 465 100 . H NMR DMF-d7 : d 4.14 4H,
x
25 W.A. Herrmann, J. Fischer, K. Ofele, G.R.J. Artus, J.
.
.
Ž
.
Ž
m, Cpsubst , 4.21 24H, Cpunsubst and Cpsubst , 4.44 4H,
Ž
.
Organomet. Chem. 530 1997 259.
x
Ž
.
Ž
Ž
.
26 W.A. Herrmann, G. Gerstberger, M. Spiegler, Organometallics
m, Cpsubst , 4.53 4H, m, Cpsubst , 5.23 4H, s, CH2 ,
5.31 4H, s, CH2 , 7.51, 7.61 4H, imidazole . 13C
NMR was not possible due to decomposition during
accumulation of the FID.
Ž
.
16 1997 2209.
¨
Ž
.
.
x
27 K. Ofele, W.A. Herrmann, D. Mihalios, M. Elison, E.
Herdtweck, T. Priermeier, P. Kiprof, J. Organomet. Chem. 498
Ž
.
1995 1.
w
Ž
.
Data for bis 1,3-di ferrocenylethyl benzimidazoline-
w
w
w
w
w
w
w
w
w
x
28 N. Kuhn, H. Bohnen, J. Fahl, D. Blaser, R. Boese, Chem. Ber.
¨
Ž .
x
Ž .
129 1996 1579.
2-ylidene mercury II dibromide 15: yellow crystals,
m.p. 1808C, dec. Anal. Found: C, 51.52; H, 4.21.
x
29 N. Kuhn, H. Bohnen, G. Henkel, J. Kreutzberg, Z. Naturforsch.
Ž
.
B 51 1996 1267.
C62 H60 Br2 Fe4 HgN4. Calcd.: C, 51.54; H, 4.19%.
IR KBr : cm 3091w, 1632m, 1560m, 1479m, 1462s,
1418s, 1346w, 1261w, 1204w, 1175m, 1103s, 1043m,
x
30 N. Kuhn, T. Kratz, D. Blaser, R. Boese, Inorg. Chim. Acta 238
¨
y1
Ž
.
Ž
.
1995 179.
x
Ž
.
31 N. Kuhn, T. Kratz, D. Blaser, R. Boese, Chem. Ber. 128 1995
¨
Ž
.
245.
1024m, 1003m, 820s, 760s, 499s, 482s. MS ESI :
mrz % 1365 0.02 M –Br , 543 100 . 1H and 13C
q
x
32 N. Kuhn, T. Kratz, R. Boese, D. Blaser, J. Organomet. Chem.
¨
Ž
.
Ž
. Ž
.
Ž
.
Ž
.
470 1994 C8.
NMR analysis was precluded by insufficient solubility.
x
33 D. Enders, K. Breueer, J. Runsink, J.H. Teles, Helv. Chim. Acta
Ž
.
79 1996 1899.
x
34 D. Enders, H. Gielen, G. Raabe, J. Runsink, J.H. Teles, Chem.
Ž
.
Acknowledgements
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35 D. Enders, K. Breuer, G. Raabe, J. Runsink, J.H. Teles, J.-P.
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.
Melder, K. Ebel, S. Brode, Angew. Chem. 107 1995 1119.
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36 D. Enders, K. Breuer, G. Raabe, J. Runsink, J.H. Teles, J.-P.
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.
Melder, K. Ebel, S. Brode, Angew. Chem. Int. Ed. Engl. 34
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.
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w
x
37 J.H. Teles, J.-P. Melder, K. Ebel, R. Schneider, E. Gehrer, W.
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