Donor-substituted CpCo-stabilized cyclobutadienes and superphanes

Article abstract of DOI:10.1016/j.jorganchem.2004.06.048

RCpCoL₂ complexes (L₂ = (CO)₂ or COD, R = H, CO₂Me, TMS) were reacted with various alkynes substituted with chalcogen atoms adjacent to the triple bonds. These reactions yielded hetero-substituted CpCo-capped cyclobutadienes and superphanes dependent on the ring size of the corresponding cyclic diene used as starting material. Reactions in decaline afforded not only CpCo-capped cyclobutadieno superphanes, but also mixed cyclobutadieno cyclopentadienono superphanes. X-ray analyses do not indicate a significant amount of conjugation between the π systems and the lone pairs of the heteroatoms whereas cyclic voltammetry reveals an easier oxidation when increasing the number of electron-donating heteroatoms.

Full text of DOI:10.1016/j.jorganchem.2004.06.048

Journal of Organometallic Chemistry 689 (2004) 3132–3142
www.elsevier.com/locate/jorganchem
Donor-substituted CpCo-stabilized cyclobutadienes and superphanes
*
Daniel B. Werz, J. Hilko Schulte, Rolf Gleiter , Frank Rominger
Organisch-Chemisches Institut der Universit a¨ t Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany
Received 16 February 2004; accepted 15 June 2004
Available online 12 August 2004
Abstract
RCpCoL complexes (L = (CO) or COD, R = H, CO Me, TMS) were reacted with various alkynes substituted with chalcogen
2
2
2
2
atoms adjacent to the triple bonds. These reactions yielded hetero-substituted CpCo-capped cyclobutadienes and superphanes
dependent on the ring size of the corresponding cyclic diene used as starting material. Reactions in decaline afforded not only
CpCo-capped cyclobutadieno superphanes, but also mixed cyclobutadieno cyclopentadienono superphanes. X-ray analyses do
not indicate a significant amount of conjugation between the p systems and the lone pairs of the heteroatoms whereas cyclic vol-
tammetry reveals an easier oxidation when increasing the number of electron-donating heteroatoms.
ꢀ
2004 Elsevier B.V. All rights reserved.
Keywords: Cyclobutadiene complexes; Alkynes; Cobalt; Superphanes
1
. Introduction
complex F. This mechanism was first suggested by
Rausch et al. [8] and is shown in Scheme 1. To get a dee-
per insight into the mechanism several intermediates
were isolated and characterized crystallographically.
Mono(alkyne)cobalt complexes could be obtained as
stable compounds by using either a highly strained [9]
or a very electron-deficient alkyne such as bis(tert-but-
ylsulfonyl)acetylene (BTSA) [10]. Cobaltols of type D
with a further ligand L could also be characterized by
means of X-ray analyses [11].
5
Dicarbonyl(g -cyclopentadienyl)cobalt [CpCo(CO) ]
2
has played a major role in organometallic chemistry
for the last 50 years [1,2]. Especially, its reactions with
alkynes [3] yielded several useful and theoretically
attractive molecules such as CpCo-stabilized cyclobuta-
dienes [4], cyclopentadienones [5,6] as well as benzene
derivatives [7]. As one possible mechanism for the gener-
ation of these species a sequential replacement of the CO
units by acetylene fragments was proposed, yielding first
a monoacetylene complex A, then a diacetylene complex
B, which is thereafter converted by an oxidative cou-
pling into a 16-electron metallacycle C (Scheme 1)
In the course of our in-depth study of electron-rich
alkynes [12–14] and their reactions with electrophilic
complex fragments [15] we elucidated the reaction of
RCpCo(COD) (1, R = CO Me) and RCpCo(CO) (2a–
2
2
[
7,8]. The latter species, the so-called cobaltol C, has
2c, R = H, CO Me, TMS) with several electron-rich
2
the ability to react either with a further acetylene frag-
ment to afford the benzene derivative G, or to form
the cyclobutadiene complex E by a reductive elimination
process, or to insert CO to afford a cyclopentadienone
alkynes [12,16]. In continuation of this work we thought
it of general interest to test the reactivity of sulfur-, sele-
nium-, and tellurium-substituted alkynes towards elec-
trophilic cobalt reagents. Several questions were in the
focus of these investigations: Which heteroelements are
tolerated by this reaction? In which way do cyclic dienes
react (formation of tricyclic cyclobutadiene complexes
versus formation of CpCo-capped superphanes [17])?
*
Corresponding author. Tel.: +49-6221-548400; fax: +49-6221-
544205.
E-mail address: rolf.gleiter@urz.uni-heidelberg.de (R. Gleiter).
0
022-328X/$ - see front matter ꢀ 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2004.06.048

D.B. Werz et al. / Journal of Organometallic Chemistry 689 (2004) 3132–3142
3133
R
R
R
R
R
R
R
Co
Co
Co
-
L
- L
L
L
L
R
R R
A
B
L
Co
Co
R
R
R
R
-
L
L
+
R
R
R
R
D
C
CO
R
R
R
R
R
R
Co
R Co
R
R
R
Chart 1.
R
R
O
R
R
R
R
E
F
G
size the hitherto unknown p systems totally surrounded
by tellurium atoms were in vain. In all other cases
mostly [2 + 2] cycloadducts were formed in moderate
yields. When using the acyclic dithiaacetylene 3, besides
the CpCo-complexed [2 + 2] cycloadduct 13 we also ob-
served the [2 + 2 + 2] cycloadduct 14 as the main
product (Scheme 2). This hexa(methylthio)-substituted
benzene 14 was previously synthesized by nucleophilic
aromatic substitution of hexachlorobenzene [19].
Scheme 1.
0
Furthermore, a,a -heterosubstituted alkynes would lead
to p systems that are completely surrounded by hetero-
atoms [18]. How do these heteroatoms influence elec-
tronic and structural properties?
In the case of the cyclic dienes 5–12 we found for 5, 8,
9, and 10 tricyclic cyclobutadiene (Cbd) complexes
2
. Results
(
Scheme 3).
For larger cycles (e.g., 6, 7, 11 and 12) at higher tem-
We used a variety of recently prepared acyclic and
cyclic, symmetrical and asymmetrical alkynes, substi-
tuted by chalcogen atoms in the a- and a,a -positions
peratures the CpCo-capped cyclobutadieno as well as
the CpCo-capped mixed cyclobutadieno cyclopentadi-
enono superphanes 19–24 resulted (Schemes 4 and 5).
At lower temperature these larger cycles did not react.
When the unsymmetrical cycles 11 and 12 were reacted
0
[
12,16] (Chart 1).
The reactions were carried out in cyclooctane or
decaline, mostly under reflux. In the case of the seleni-
um-containing compound 8, the reaction was carried
out at 90 ꢁC, because at higher temperatures decompo-
sition was observed. All these temperatures proved to
with RCpCo(CO) two different cyclobutadieno super-
2
phanes were possible, either the 1,2-isomer with adjacent
hetero-substituents or the 1,3-isomer with nonadjacent
hetero-substituents (Scheme 5). In all cases we found
only the 1,2-isomers of the cyclobutadieno superphanes
0
be too high for the a,a -tellurium-substituted alkyne 4.
The Te–C bond is so weak that all attempts to synthe-
S
E
E
S
S
S
S
a
Co
Co
+
2
S
S
+
S
S
S
S
S
1
3
13
14
a) cyclooctane; 120 ˚C
2
E = CO Me
Scheme 2.

3134
D.B. Werz et al. / Journal of Organometallic Chemistry 689 (2004) 3132–3142
X
X
X
X
E
E
b
Co
+
2
(H C)
2 n
(CH )
Co
n
X
X
(
H2C)n-2
(CH2)n-2
X
X
1
5 (n = 3; X = S)
(n = 4; X = Se)
15 (n = 3; X = S)
16 (n = 4; X = Se)
8
b) 5: cyclooctane, 130 ˚C; 8: cyclooctane, 90 ˚C
E = CO2Me
S
R
R
c
Co
+
(H2C)n
(CH2)m
Co
S
OC
CO
(
H2C)n-2
S
(CH2)m-4
S
2
2
2
a (R = H)
b (R = CO Me)
c (R = TMS)
9 (n = 3; m = 5)
10 (n = 5; m = 5)
17a (n = 3; m = 5; R = H)
17b (n = 3; m = 5; R = CO Me)
17c (n = 3; m = 5; R = TMS)
2
2
1
8 (n = 5; m = 5; R = CO Me)
2
c) decaline, 200 ˚C
Scheme 3.
22 and 23. Note, that in Scheme 5 the 1,3-isomers are
also shown for the sake of clarity.
iochemistry is the formation of the cobaltol C from the
diacetylene complex B.
To explain the preference of the 1,2-isomers (1,2)-22
and (1,2)-23 we use a qualitative model. Assuming that
the reaction sequence follows the path illustrated in
Scheme 1, the most important step that decides the reg-
Taking into account H u¨ ckel-type calculations on sim-
ple a-thiosubstituted alkynes, a strong polarization of
the alkyne unit results giving rise to large coefficients
of the HOMO at the sulfur center and the carbon center
in b-position of the sulfur. One may assume that such a
polarization still exists in the diacetylene complex B
where two regioisomers are equilibrating with each
E
S
S
S
S
other. Of three possible regioisomeric cobaltols C
0
d
Co
+
(H2C)n
(CH2)n
(
R
6
OC
CO
in which the large AO coefficients at the b-carbon atoms
form the new bond [20]. This effect leads to the (1,2)-reg-
ioisomer. A similar argument has been put forward to
explain the formation of the C2v symmetric superphanes,
when cyclic dienes, substituted at one a-position with
SiMe groups, were reacted with CpCoL [21].
2b
6
7
(n = 5)
(n = 6)
E
E
Co
Co
All the obtained p complexes 13 and 15–24 are
remarkably stable. They are inert towards moisture
S
S
S
S
S
S
S
S
1
3
(
CH2)n
(CH2)n
and air. Investigations of the C NMR spectra reveal
chemical shifts of the carbon signals of the cyclobutad-
iene ring totally surrounded by sulfur in the range be-
tween d = 80–82. In the case of selenium, this value is
(
CH2)n
(CH2)n
O
+
(
H2C)n
(H2C)n
2 n
(CH )
b2
(CH2)n
S
S
S
S
S
a1
a2
S
S
b1
S
Co
Co
E
E
1
shifted to higher field (d = 74). By means of H NMR
experiments it is possible to differentiate the regioiso-
mers of the tetrathia-superphanes 22 and 23. In the case
of the (1,2)-regioisomers the CH groups adjacent to the
1
2
9 (n = 5)
1 (n = 6)
20 (n = 5)
2
cyclobutadiene rings provide diastereotopic protons
whereas in the case of the (1,3)-regioisomers homotopic
1
protons result. The observed splitting in the H NMR
spectra of 22 and 23 clearly shows that only the (1,2)-
d) decaline, 170 ˚C
2
E = CO Me
Scheme 4.

D.B. Werz et al. / Journal of Organometallic Chemistry 689 (2004) 3132–3142
3135
E
S
S
planes (of the Cbd and the Cp units). In Table 1 we
have compared the most relevant distances and inter-
planar angles. The C–C bond lengths in the Cbd rings
are slightly longer than those in the unsubstituted
CpCo cyclobutadiene complex (144 pm) [22]. We as-
cribe this behavior to a combination of steric and elec-
tronic effects due to the donor substitution of the Cbd
units. There is no significant indication of bond alter-
nation in the four-membered rings, neither in the sym-
metrically nor in the asymmetrically substituted ones.
Nevertheless, the values of the asymmetrically substi-
tuted complexes have to be taken with care because S
e
Co
+
(H2C)n
(CH2)m
OC
CO
2b
11 (n = 5, m = 7)
2 (n = 6, m = 8)
1
E
E
Co
Co
S
S
S
S
(
(
CH2)m-2
(
CH2)m-2
(
CH2)n
CH2)m-2
+
+
(
H2C)n
and CH moieties are too similar in their spatial de-
2
b2
(CH2)n
(
H2C)n
(
CH2)m-2
a1
a2
b1
S
S
mand and therefore in most cases disorder between
these two groups was observed.
S
S
Co
Co
E
E
In the cyclobutadiene complex 13 we encountered
two independent molecules differing from each other
in the conformation of the SMe groups. In Fig. 1, we
show as an example the tricyclic cyclobutadiene com-
plex with two seven-membered rings which are fused
to the cyclobutadiene complex.
(
(
1,2)-22 (n = 5, m = 7)
1,2)-23 (n = 6, m = 8)
(1,3)-22 (n = 5, m = 7)
(1,3)-23 (n = 6, m = 8)
E
E
The molecular structure of hexa(methylthio)-ben-
zene (14) shows a center of inversion. Three adjacent
SMe groups point up, three point down. Another con-
formation of this compound was reported previously
[23]. Due to the donor-substitution the p* orbitals of
the benzene skeleton are populated. Thus, as a result
the bond distances in the six-membered ring are
slightly enlarged (1.5–2.0 pm compared with unsubsti-
tuted benzene).
Co
Co
S
S
S
S
(CH2)
O
(CH2)m-2
O
(CH )
(
CH2)m-2
2 n
m-2
and/
or
(
H2C)n
(CH2)n
2
(H C)
n
(
CH2)m-2
S
S
S
S
Co
Co
E
E
In Fig. 2 we compare the two octathia-superphanes
9 and 21. Both of them crystallize in the triclinic space
(
2,5)-24 (n = 6, m = 8)
(2,4)-24 (n = 6, m = 8)
1
ꢀ
group P1 showing a center of inversion. As a result, the
Cbd planes are parallel to each other. 19 contains two
independent half molecules and three molecules of
e) decaline, 200 ˚C
E = CO Me
2
Scheme 5.
partly disordered CHCl in the asymmetric unit. The
3
bridging alkane chains reveal a strain-free zig-zag con-
formation. Thus, the distance between the two p sys-
tems becomes as large as possible. In the case of 19
this distance is 818 pm (and 820 pm, respectively),
regioisomers were found. Due to the rather complicated
spectrum of 24 such a clear-cut decision in favour of the
whereas in 21 due to one further CH unit the distance
2
(
case of 24 three isomers are conceivable (2,4-, 2,5-,
1,2)-regioisomer was not possible. In principle, in the
amounts to 960 pm. To the best of our knowledge,
these are the largest CpCo-stabilized superphanes re-
ported so far [24]. In the case of 19 the two Cbd moi-
eties are situated on top of each other. In contrast, in
the structure of 21 they are shifted by 256 pm against
each other. As a result, the Co–Co axis in 21 is inclined
by 11.6ꢁ. This observation is shown in Fig. 3. A similar
shifting is observed for the tetrathia-superphane
and 3,4-), none of which has homotopic protons in the
CH groups. Thus our earlier criterion of homotopicity
is no longer applicable.
2
3
. Structural investigations and cyclic voltammetry
(1,2)-23 compared to the smaller tetrathia-superphane
Of the 14 products obtained from the aforemen-
tioned reactions, the products 13–15, 17b, 19, 21,
1,2)-22 and (1,2)-23 yielded single crystals which could
be investigated by means of X-ray diffraction to study
their molecular structures in more detail. The X-ray
structures of all p complexes reveal two nearly parallel
(1,2)-22. In the superphane resulting from cycloocta-
deca-1,10-diene and CpCo(COD) with heptamethylene
chains between the cyclobutadiene units two conforma-
tions were also reported in the solid state: in the first
the centers of the parallel cyclobutadiene rings are
situated on top of each other, in the second the centers
(

3136
D.B. Werz et al. / Journal of Organometallic Chemistry 689 (2004) 3132–3142
Table 1
Relevant geometric parameters of the compounds 13, 15, 17b, 19, 21, (1,2)-22 and (1,2)-23
f
2
f
Compound
d(Co–Cp)
d(Co–Cbd)
/(Cp–Cbd)
d(Cbd–Cbd)
a
1
, a
146.2(3)
46.6(3)
146.6(3)
46.8(3)
145.5(6)
47.1(6)
144.8(3)
44.5(3)
145.3(9)
47.3(9)
144.9(9)
46.9(9)
146.4(3)
47.5(3)
146.2(3)
47.1(3)
146.5(3)
47.1(3)
1 2
b , b
a
1
3
168.3(2)
168.4(2)
4.1(1)
–
146.1(3)
146.7(3)
145.9(3)
146.1(3)
145.4(6)
146.0(6)
145.8(3)
145.0(3)
146.2(9)
146.3(9)
144.8(9)
148.0(9)
147.1(3)
147.5(3)
146.7(3)
147.2(3)
145.8(4)
146.4(4)
1
1
67.9(2)
167.8(2)
169.4(4)
169.3(2)
167.0(7)
166.6(7)
167.0(2)
167.4(2)
168.0(2)
2.9(1)
2.6(3)
2.9(2)
0.6(6)
2.2(6)
3.2(2)
3.0(2)
0.7(2)
–
1
1
1
1
5
169.5(4)
168.6(2)
166.6(7)
–
1
b
7b
–
1
a,d
9
818.1(7)
820.1(7)
925.2(2)
1
1
67.8(7)
1
2
1
166.7(2)
167.3(2)
167.5(3)
1
e
c
(
1,2)-22
1,2)-23
a
797.9(2)
1
b,d
(
834.4(2)
1
Two independent molecules exist in the asymmetric unit.
b
c
d
e
f
Disorder between the S and the CH
2
moieties, the values have to be taken with a grain of salt.
Mean value.
Special position with inversion symmetry.
Special position on mirror plane.
1 2 1 2
A definition of a , a , b and b is given in Schemes 4 and 5.
plex 17a. The effect of the sulfur substituents at the Cbd
ring can be seen by comparing 15 with 17b: The complex
with four donors (15) is easier to oxidize than the one
with only two donors (17b). Furthermore, selenium (16)
seems to be a worse donor than sulfur which can be
rationalized by its smaller overlap with the Cbd unit. A
potential splitting of the CV of superphanes was not ob-
served. The distance between the p systems is too large for
any significant interaction. The latter result is in line with
studies on superphanes where the distance between the p
systems was varied between 300 and 700 pm [17a].
4
. Conclusion
Fig. 1. ORTEP plot (50% ellipsoid probability) of the molecular
structure of 15. Hydrogen atoms are omitted for the sake of clarity.
In this paper, we have shown that sulfur- and seleni-
um-substituted alkynes are able to react with RCpCoL2
to afford donor-substituted p complexes or benzene
derivatives. Dependent on the ring size of cyclic dienes
which served as starting materials tricyclic cyclobutadi-
ene complexes and CpCo-capped superphanes, respec-
tively, are formed. Asymmetrically substituted alkynes
yield only one regioisomer with the heteroatoms adja-
cent to each other. All donor-substituted complexes
are stable at room temperature and resistant to water
and oxygen. The X-ray analyses indicate that conjuga-
tion between the p system and the adjacent lone pairs
of the sulfur substituents does not play a major role.
CV reveals an easier oxidation when the number of sul-
fur substituents is increased.
of the parallel cyclobutadiene units are displaced by
1
02 pm [24].
To probe further effects of the donor-substitution, we
have carried out studies by means of cyclic voltammetry
CV). In general, an oxidation potential measured by CV
(
can be correlated with the HOMO energy of the corre-
sponding complex [25]. Donors should raise the orbital
energy, whereas acceptors should lower it. All recorded
oxidation potentials are listed in Table 2. A comparison
of 17a–17c differing only by the substituent at the Cp ring
reveals a slightly electron-donating effect of the TMS
group (17c) and a slightly electron-withdrawing effect
of the ester moiety (17b) versus the unsubstituted com-

D.B. Werz et al. / Journal of Organometallic Chemistry 689 (2004) 3132–3142
3137
Fig. 2. ORTEP plots (50% ellipsoid probability) of the molecular structures of 19 (left) and 21 (right). Hydrogen atoms are omitted for the sake of
clarity.
Fig. 3. Top view of the Cbd planes of 19 (left) and 21 (right). The CpCo fragments and the hydrogen atoms are omitted for the sake of clarity.
5
. Experimental
phy: neutral alumina (Merck), silica gel 60 (Machery-
1
Nagel), Celite (Fluka). H NMR and C NMR: Bruker
13
1
13
Avance 300 ( H at 300 MHz and C at 75 MHz), Bru-
5
.1. General remarks
1
13
ker Avance 500 ( H at 500 MHz and C at 125 MHz)
using the solvent as internal standard. IR: Bruker Vec-
tor 22 FT-IR. UV/Vis: Hewlett–Packard 8452 A spec-
Moisture- and oxygen-sensitive reactions were con-
ducted in oven-dried glassware under argon using dried
solvents. Cyclooctane and decaline were dried with sodi-
um-benzophenone and distilled before use; m.p. are
uncorrected. Materials used for column chromatogra-
+
trometer. MS (FAB ): High resolution: Jeol JMS-700.
Elemental analyses were carried out by the Mikroanaly-
tisches Laboratorium der Universit a¨ t Heidelberg. The

3138
D.B. Werz et al. / Journal of Organometallic Chemistry 689 (2004) 3132–3142
Table 2
Comparison of oxidation potentials E of several donor-substituted
cyclobutadiene complexes
CH CHHCH ), 2.61 (m, 8H, SCHH), 3.72 (s, 3H,
2 2
13
OCH ), 4.96 (m, 2H, CpH), 5.78 (m, 2H, CpH).
3
C
NMR (75 MHz, CDCl ): d 34.1 (CH ), 37.0 (CH ),
3
2
2
Compound
E (mV)
51.1 (OCH ), 81.8 (C(Cbd)), 84.2 (C(Cp)H), 85.1
3
(C(Cp)H), 88.0 (C(Cp)), 166.8 (CO). IR (KBr): 2945,
1
1
1
1
1
1
1
1
3
410
190
410
200
330
160
420
5
2
916, 2054, 1708, 1637, 1466, 1400, 1282. UV–vis
ꢀ1
+
76 (4.12), 320 (3.44), 372 (3.33). HRMS (FAB )
6
(CH Cl , 0.062 mg ml ) k [nm] (log e): 238 (4.28),
2
2
7a
7b
7c
8
2
C H O S Co: Calc.: 441.9600. Found: 441.9587. Ele-
1
7
19
2 4
mental Anal. Calc.: C, 46.14; H, 4.33; S, 28.98. Found:
C, 46.21; H, 4.39; S, 28.76%.
a
9
450
530
(1,2)-22
a
Irreversible.
5
.2.3. Cyclobutadiene complex 16
Starting materials: 140 mg (0.48 mmol) of CpECo-
(COD) (1) and 230 mg (0.48 mmol) of 1,4,9,12-tetra-
selenacyclohexadeca-2,10-diene (8) in 50 ml of
starting materials were prepared according to literature
methods [12,16,26].
cyclooctane. The mixture is stirred for 12 d at 90 ꢁC.
Yield: 95 mg (30%). Yellow-orange solid; m.p. 65 ꢁC.
5.2. General procedure for the formation of heterosubsti-
tuted cyclobutadiene complexes and superphanes
1
H NMR (300 MHz, CDCl ): d 1.93 (m, 4H,
3
CH CHHCHHCH ), 2.08 (m, 4H, CH CHHCH-
HCH ), 2.88 (m, 4H, SeCHH), 2.96 (m, 4H, SeCHH),
2
2
2
2
The appropriate cobalt complex (ECpCo(COD) or
RCpCo(CO) ) is dissolved in cyclooctane or decaline
3
.84 (s, 3H, OCH ), 4.95 (m, 2H, CpH), 5.36 (m, 2H,
3
2
13
CpH). C NMR (75 MHz, CDCl ): d 26.0 (CH ),
3
2
and the heterosubstituted alkyne is added in one por-
tion. The reaction mixture is stirred for several days un-
der heating. After completion of the reaction, the crude
mixture is purified twice by column chromatography
2
8.4 (CH2), 51.6 (OCH3), 74.4 (C(Cbd)), 84.4
C(Cp)H), 86.2 (C(Cp)H), 87.7 (C(Cp)), 166.6 (CO).
(
IR (KBr): 2945, 2850, 1715, 1671, 1466, 1433, 1364,
1
ꢀ1
280, 1212, 1141. UV–vis (CH Cl , 0.052 mg ml ) k
2
2
(
SiO or alumina and a gradient of n-hexane/diethyl-
2
[
(
6
nm] (log e): 234 (4.54), 318 (4.16), 356 (3.54). HRMS
ether 1:0 ! 1:1 or a gradient of n-hexane/dichlorometh-
+ 78 80
FAB ) C H O Se Se Co: Calc.: 659.7699. Found:
59.7666.
19 23 2 3
ane/methanol as eluent).
5
.2.1. Cyclobutadiene complex 13
Starting materials: 177 mg (0.61 mmol) of CpECo
COD) (1) and 132 mg (1.12 mmol) of 2,5-dithiahex-3-
5
.2.4. Cyclobutadiene complex 17a
Starting materials: 180 mg (1.0 mmol) of CpCo(CO)2
(
(
6
2a) and 224 mg (1.0 mmol) of 1,5-dithiacyclotetradeca-
,13-diene (9) in 60 ml of decaline. The mixture is stirred
yne (3) in 80 ml of cyclooctane. The mixture is stirred
for 5 d at 120 ꢁC. Yield: 87 mg (34%) of 13 and 46 mg
for 2 d at 200 ꢁC. Yield: 205 mg (59%). Orange solid;
1
(
35%) of 14. Analytical data of 13: Yellow solid.; m.p.
1
m.p. 83 ꢁC. H NMR (300 MHz, CDCl ): d 1.29–2.22
3
5
SCH ), 2.82 (s, 3H, OCH ), 5.04 (ps, 2H, CpH), 5.49
8 ꢁC. H NMR (500 MHz, CDCl ): d 2.35 (s, 12H,
3
(m, 10H, CH ), 2.60–3.11 (m, 6H, CH ), 4.81 (m, 5H,
1
2
2
3
3
3
CpH). C NMR (75 MHz, CDCl ): d 27.6 (CH ),
3 2
1
3
(
m, 2H, CpH). C NMR (125 MHz, CDCl ): d 18.1
3
30.1 (CH ), 30.4 (CH ), 35.2 (CH ), 38.4 (CH ), 79.2
2 2 2 2
(
SCH ), 51.6 (OCH ), 82.1 (C(Cbd)), 83.4 (C(Cp)H),
3
3
(C(Cp)H), 80.2 (C(Cbd)), 81.5 (C(Cbd)). IR (KBr):
8
2
5.1 (C(Cp)H), 87.6 (C(Cp)), 166.9 (CO). IR (KBr):
921, 2054, 1715, 1639, 1510, 1467, 1282. UV–vis
2
0
922, 2845, 2820, 1627, 1418, 806. UV–vis (CH Cl ,
2 2
ꢀ
1
.137 mg ml ) k [nm] (log e): 378 (3.24), 326 (3.37),
ꢀ1
+
(
CH Cl , 0.099 mg ml ) k [nm] (log e): 234 (4.38),
2
2
294 (4.40). HRMS (FAB ) C H S Co: Calc.:
17 21 2
+
3
18 (4.22), 358 (3.51). HRMS (FAB ) C H O S Co:
15 19 2 4
348.0417. Found: 348.0388.
Calc.: 417.9600. Found: 417.9542. Elemental Anal.
Calc.: C, 43.05; H, 4.58; S, 30.65. Found: C, 43.31; H,
5
.2.5. Cyclobutadiene complex 17b
Starting materials: 239 mg (1.0 mmol) of CpECo-
CO) (2b) and 224 mg (1.0 mmol) of 1,5-dithiacyclo-
4
.64; S, 30.58%.
(
2
5
.2.2. Cyclobutadiene complex 15
Starting materials: 56 mg (0.19 mmol) of CpECo
COD) (1) and 50 mg (0.19 mmol) of 1,4,8,11-tetrathia-
tetradeca-6,13-diene (9) in 60 ml of decaline. The
mixture is stirred for 2 d at 200 ꢁC. Yield: 330 mg
(80%). Yellow solid; m.p. 130 ꢁC (recrystallized from
(
1
cyclotetradeca-2,9-diene (5) in 50 ml of cyclooctane. The
mixture is stirred for 8 d at 130 ꢁC. Yield: 44 mg (52%).
Yellow-orange solid; m.p. 165 ꢁC. H NMR (300 MHz,
C D ): d 1.55 (m, 2H, CH CHHCH ), 1.90 (m, 2H,
CH Cl ). H NMR (300 MHz, CDCl ): d 0.90 (m, 2H,
2
2
3
CH ), 1.61 (m, 4H, CH ), 1.93 (m, 2H, CH ), 2.61 (m,
4H, CH ), 2.90 (m, 4H, CH ), 2.91 (s, 3H, CH ), 4.93
2 2 3
2
2
2
1
1
(s, 2H, CpH), 5.59 (s, 2H, CpH). C NMR (75 MHz,
3
6
6
2
2

D.B. Werz et al. / Journal of Organometallic Chemistry 689 (2004) 3132–3142
3139
CDCl ): d 26.9 (CH ), 29.5 (CH ), 29.8 (CH ), 34.1
16H, SCH CH ), 2.67 (m, 16H, SCH ), 3.77 (s, 6H,
2 2 2
3
2
2
2
1
3
(
CH ), 37.4 (CH ), 51.0 (OCH ), 80.1 (C(Cbd)), 81.9
3
OCH ), 4.81 (m, 4H, CpH), 5.15 (m, 4H, CpH).
3
C
2
2
(
1
1
C(Cp)H), 82.4 (C(Cbd)), 83.5 (C(Cp)H), 88.9 (C(Cp)),
56.1 (CO). IR (KBr): 2920, 2857, 1710, 1637, 1466,
NMR (75 MHz, CD Cl ): d 29.7 (CH ), 32.5 (CH ),
2 2 2 2
33.5 (CH2), 51.8 (OCH3), 80.1 (C(Cbd)), 85.4
(C(Cp)H), 87.4 (C(Cp)H), 87.9 (C(Cp)), 166.8 (CO).
IR (KBr): 2947, 2925, 2854, 1718, 1627, 1466, 1282,
365, 1282, 1142, 773. UV–vis (CH Cl , 0.043 mg
2
2
ꢀ1
ml ) k [nm] (log e): 370 (2.94), 332 (3.25), 300 (4.32).
+
HRMS (FAB ) C H S O Co: Calc.: 406.0472. Found:
ꢀ1
1144. UV–vis (CH Cl , 0.073 mg ml ) k [nm] (log e):
1
9
23
2
2
2
2
+
4
06.0466. Elemental Anal. Calc. C H S O
2-
242 (4.64), 318 (4.58), 352 (3.63). HRMS (FAB )
C H O S Co : Calc.: 996.0452. Found: 996.0400. Ele-
mental Anal. Calc.: C, 50.58; H, 5.46; S, 25.72. Found:
1
9
23
2
Co Æ 0.1CH Cl : C, 55.29; H, 5.64. Found: C, 55.31; H,
5
2
2
42 54
4
8
2
.60%.
C, 50.80; H, 5.58; S, 25.25%. Analytical data of 20:
1
5
.2.6. Cyclobutadiene complex 17c
Starting materials: 252 mg (1.0 mmol) of CpT-
Red solid; m.p. > 250 ꢁC. H NMR (300 MHz, CD Cl ):
2
2
d 1.10–1.54 (m, 18H, CH ), 2.23 (m, 2H, CHH), 2.40 (pt,
2
MSCo(CO) (2c) and 224 mg (1.0 mmol) of 1,5-dithiacy-
2
4H, SCHH), 2.54 (pt, 4H, SCHH), 2.56–2.83 (m, 8H,
CH ), 3.12 (m, 4H, SCHH), 3.71 (s, 3H, OCH ), 3.79
clotetradeca-6,13-diene (9) in 60 ml of decaline. The
mixture is stirred for 2 d at 200 ꢁC. Yield: 196 mg
2
3
(s, 3H, OCH ), 4.18 (m, 2H, SCH H), 4.75 (m, 2H,
3
1
(
47%). Orange oil. H NMR (300 MHz, CDCl ): d
CpH), 4.79 (m, 2H, CpH), 5.00 (m, 2H, CpH), 5.09
1
3
3
0
CH ), 1.95 (m, 4H, CH ), 2.51 (m, 2H, CH ), 2.89 (m,
.12 (s, 9H, CH ), 1.01 (m, 2H, CH ), 1.52 (m, 4H,
(m, 2H, CpH). C NMR (75 MHz, CD Cl ): d = 28.9
2 2
3
2
(CH ), 29.0 (CH ), 29.6 (CH ), 31.8 (CH ), 31.8
2 2 2 2
2
2
2
1
3
4
H, CH ), 4.81 (s, 2H, CpH), 5.08 (s, 2H, CpH).
2
C
(CH ), 31.9 (CH ), 31.9 (CH ), 32.2 (CH ), 34.0
2 2 2 2
NMR (75 MHz, CDCl ): d 0.1 (CH ), 26.7 (CH ),
(CH ), 36.0 (CH ), 51.7 (OCH ), 52.3 (OCH ), 81.9
2 2 3 3
3
3
2
3
0.0 (CH ), 30.4 (CH ), 34.2 (CH ), 38.2 (CH ), 79.2
2
(C), 82.2 (C), 85.0 (C(Cp)H), 85.0 (C), 86.9 (C(Cp)H),
88.0 (C(Cp)H), 88.1 (C), 88.2 (C), 89.3 (C), 90.2
(C(Cp)H), 155.8 (CO), 163.8 (COO), 166.0 (COO). IR
(KBr): 2927, 2854, 1720, 1600, 1469, 1366, 1282, 1145.
2
2
2
(
C(Cbd)), 81.2 (C(Cbd)), 84.48 (C(Cp)), 84.53 (C(Cp)),
8
7
3
5.8 (C(Cp)). IR (KBr): 2961, 1414, 1261, 1034, 801,
ꢀ1
40. UV–vis (CH Cl , 0.252 mg ml ) k [nm] (log e):
2
2
+
88 (3.14), 334 (3.28), 298 (4.29). HRMS (FAB )
ꢀ1
UV–vis (CH Cl , 0.026 mg ml ) k [nm] (log e): 240
2
2
+
C H S SiCo: Calc.: 420.0812. Found: 420.0784.
2
(4.58), 314 (4.30), 366 (4.23). HRMS (FAB )
C H O S Co : Calc.: 1025.0480. Found: 1025.0490.
0
29 2
4
3
54
5
8
2
5
.2.7. Cyclobutadiene complex 18
Starting materials: 239 mg (1.0 mmol) of CpECo
5.2.9. Cyclobutadieno superphane 21
Starting materials: 287 mg (1.20 mmol) of CpECo
(
hexadeca-8,15-diene (10) in 60 ml of decaline. The mix-
CO) (2b) and 252 mg (1.0 mmol) of 1,7-dithiacyclo-
2
(CO) (2b) and 414 mg (1.20 mmol) of 1,4,11,14-tetrathi-
2
ture is stirred for 2 d at 200 ꢁC. Yield: 93 mg (21%).
acycloeicosa-2,12-diene (7) in 50 ml of decaline. The
mixture is stirred for 2 d at 160–170 ꢁC. Yield: 74 mg
1
Yellow oil. H NMR (300 MHz, CDCl ): d 0.80–1.03
3
1
(
m, 2H, CH ), 1.12–1.73 (m, 10H, CH ), 1.88–2.19 (m,
(12%). Yellow solid; m.p. 221 ꢁC. H NMR (500
2
2
4
OCH ), 4.02 (s, 2H, CpH), 5.40 (s, 2H, CpH).
H, CH ), 2.39–2.87 (m, 4H, CH ), 3.75 (s, 3H,
1
MHz, CDCl ): d 1.36 (b, 16H, SCH CH CH ), 1.62
2
2
3
2
2
2
3
C
(b, 16H, SCH CH ), 2.71 (b, 16H, SCH ), 3.80 (b, 6H,
2 2 2
3
1
3
NMR (75 MHz, CDCl ): d 19.5 (CH ), 24.5 (CH ),
OCH ), 4.92 (b, 4H, CpH), 5.34 (b, 4H, CpH).
3
C
3
2
2
2
6.0 (CH ), 29.4 (CH ), 29.9 (CH ), 34.4 (CH ), 51.2
2
NMR (125 MHz, CDCl ): d 28.1 (SCH CH CH ),
3 2 2 2
2
2
2
(
OCH ), 74.1 (C(Cbd)), 82.4 (C(Cp)H), 83.7 (C(Cp)H),
3
30.1 (SCH CH ), 35.8 (SCH ), 51.7 (OCH ), 82.4
2 2 2 3
8
2
4.9 (C(Cbd)), 91.3 (C(Cp)), 167.5 (CO). IR (KBr):
920, 2858, 1716, 1466, 1281, 1141, 821, 736. UV–vis
(C(Cbd)), 84.0 (C(Cp)H), 85.9 (d, C(Cp)H), 87.6 (s,
C(Cp)), 166.6 (s, CO). IR (KBr): 2926, 1718, 1628,
ꢀ
1
ꢀ1
(
CH Cl , 0.159 mg ml ) k [nm] (log e): 370 (2.95),
1469, 1366, 1284. UV–vis (CH Cl , 0.035 mg ml ) k
2
2
2
2
3
(
38 (3.21), 320 (3.34), 284 (4.20), 262 (4.09). HRMS
[nm] (log e): 238 (4.64), 342 (4.62), 314 (3.34), 356
+
FAB ) C H S O Co: Calc.: 434.0784. Found:
+
(3.61). HRMS (FAB ) C H O S Co : Calc.:
1052.1078. Found: 1052.1099.
2
1
27
2
2
46 62
4
8
2
4
34.0816.
5.2.8. Cyclobutadieno superphane 19 and cyclobutadieno
cyclopentadienono superphane 20
5.2.10. Cyclobutadieno superphane (1,2)-22
Starting materials: 239 mg (1.0 mmol) of CpECo
Starting materials: 287 mg (1.20 mmol) of CpECo
CO) (2b) and 382 mg (1.20 mmol) of 1,4,10,13-tetrathi-
(CO) (2b) and 281 mg (1.0 mmol) of 1,7-dithiacyclooc-
2
(
tadeca-8,17-diene (11) in 60 ml of decaline. The mixture
is stirred for 2 d at 200 ꢁC. Yield: 231 mg (25%). Yellow
2
acyclooctadeca-2,11-diene (6) in 50 ml of decaline. The
mixture is stirred for 2 d at 160–170 ꢁC. Yield: 140 mg
1
solid; m.p. 203 ꢁC (recrystallized from toluene).
H
(
23%) of 19 and 71 mg (12%) of 20. Analytical data of
1
NMR (300 MHz, CDCl ): d 0.80–1.81 (m, 32H, CH ),
3 2
1
9: Yellow solid; m.p. > 250 ꢁC. H NMR (500 MHz,
2.14–2.18 (m, 4H, CH ), 2.22–2.25 (m, 4H, CH ),
2 2
CD Cl ): d 1.18 (m, 8H, SCH CH CH ), 1.52 (m,
2.34–2.44 (m, 4H, CH ), 2.45–2.54 (m, 4H, CH ), 3.79
2
2
2
2
2
2
2

3140
D.B. Werz et al. / Journal of Organometallic Chemistry 689 (2004) 3132–3142
(
1
s, 6H, OCH ), 4.78 (s, 4H, CpH), 5.15 (s, 4H, CpH).
3
21.5 (CH ), 25.8 (CH ), 28.6 (CH ), 28.8 (CH ), 29.3
2 2 2 2
3
C NMR (75 MHz, CDCl ): d 26.1 (CH ), 29.5
(CH ), 29.6 (CH ), 30.7 (CH ), 36.4 (CH ), 51.4
2 2 2 2
3
2
(
(
(
1
1
CH ), 29.6 (CH ), 30.5 (CH ), 30.9 (CH ), 31.2
2
(OCH ), 77.8 (C(Cbd)), 82.9 (C(Cp)H), 84.9 (C(Cp)H),
3
2
2
2
CH ), 34.8 (CH ), 51.4 (OCH ), 75.4 (C(Cbd)), 83.6
2
85.6 (C(Cbd)), 87.7 (C(Cp)), 167.5 (CO). IR (KBr):
2
3
C(Cp)H), 85.9 (C(Cbd)), 86.3 (C(Cp)H), 87.6 (C(Cp)),
67.3 (CO). IR (KBr): 2927, 2854, 1712, 1637, 1466,
2927 (s), 2853 (m), 1716 (s), 1637 (m), 1466 (s), 1281
ꢀ
(s), 1142 (s), 773 (w). UV–vis (CH Cl , 0.098 mg ml )
2 2
1
ꢀ
1
284, 1143, 775. UV–vis (CH Cl , 0.038 mg ml ) k
k [nm] (log e): 376 (3.40), 332 (3.72), 290 (4.56), 266
(4.44). HRMS (FAB ) C H S O Co : Calc.:
2
2
+
[
(
nm] (log e): 380 (3.16), 328 (3.61), 296 (4.42), 260
5
0
70
4
4
2
+
4.29). HRMS (FAB ) C H S O Co : Calc.:
980.2821. Found: 980.2756. Elemental Anal. Calc.: C,
61.20; H, 7.19; S, 13.07. Found: C, 61.03; H, 7.14; S,
1
13.00%. Analytical data of 24: Orange oil. H NMR
4
6
62
4
4
2
9
24.2195. Found: 924.2172. Elemental Anal. Calc.
C H S O Co Æ 0.5C H : C, 61.22; H, 6.85; S, 13.21.
4
6
62
4
4
2
7
8
Found: C, 61.26; H, 6.91; S, 13.13%.
(500 MHz, CDCl ): d 1.20–1.65 (m, 40H, CH ), 1.85
3
2
(
m, 4H, CH ), 1.92 (m, 4H, CH ), 2.29 (m, 4H, CH ),
2 2 2
5.2.11. Cyclobutadieno superphane (1,2)-23 and cyclo-
butadieno cyclopentadienono superphane 24
2.45 (m, 4H, CH ), 3.79 (s, 3H, CH ), 3.87 (s, 3H,
2 3
OCH ), 4.81 (s, 2H, CpH), 5.08 (m, 4H, CpH), 5.21 (s,
3
1
3
Starting materials: 175 mg (0.73 mmol) of CpECo-
CO) (2b) and 225 mg (1.20 mmol) of 1,8-dithiacycloe-
2H, CpH). C NMR (125 MHz, CDCl ): d 25.4
3
(
(CH ), 27.1 (CH ), 27.5 (CH ), 27.6 (CH ), 28.2
2
2
2
2
2
icosa-9,19-diene (12) in 60 ml of decaline. The mixture is
stirred for 2 d at 200 ꢁC. Yield: 40 mg (6%) of (1,2)-23
and 23 mg (3%) of 24. Analytical data of (1,2)-23: Yel-
(CH ), 28.4 (CH ), 28.6 (CH ), 29.1 (CH ), 29.2
2 2 2 2
(CH ), 29.4 (CH ), 29.5 (CH ), 35.8 (CH ), 51.1
2
2
2
2
(OCH ), 51.7 (OCH ), 66.2 (C), 66.4 (C), 75.9 (C),
3 3
1
low solid; m.p. 162 ꢁC. H NMR (500 MHz, CDCl ):
76.2 (C), 76.4 (C), 82.5 (C(Cp)H), 84.5 (C(Cp)H), 85.3
(C), 86.9 (C(Cp)H), 89.2 (C), 130.0 (C), 165.0 (CO),
167.3 (CO). IR (KBr): 2935, 2867, 1685, 1617, 1460,
3
d 1.29 (m, 24H, C H ), 1.45 (m, 8H, CH ), 1.52 (m,
2
2
8
H, CH ), 1.93 (m, 4H, CH ), 2.03 (m, 4H, CH ), 2.52
2 2 2
ꢀ1
(
5
m, 8H, CH ), 3.78 (s, 6H, OCH ), 4.83 (s, 4H, CpH),
2
1290, 753. UV–vis (CH Cl , 0.172 mg ml ) k [nm]
2 2
3
1
3
.20 (s, 4H, CpH). C NMR (125 MHz, CDCl ): d
(log e): 418 (3.46), 382 (3.63), 338 (4.15), 288 (4.37),
3
Table 3
Crystallographic data and details of the refinement procedure for 13–15 and 17b
1
3
14
15
17b
Empirical formula
Formula mass (g/mol)
Crystal size (mm)
Crystal colour
C
418.50
15
H
19
O
2
S
4
Co
C
354.66
12
H
18
S
6
C
442.53
17
H
19
O
2
S
4
Co
C
406.42
19
H
23CoO
2 2
S
0.29 · 0.26 · 0.12
Yellow
0.20 · 0.20 · 0.12
Yellow
0.30 · 0.06 · 0.02
Yellow
Needle
Monoclinic
C2/c
0.40 · 0.19 · 0.18
Yellow
Polyhedron
Monoclinic
C2/c
Crystal shape
Crystal system
Polyhedron
Monoclinic
Polyhedron
Triclinic
ꢀ
Space group
˚
1
P2 /c
P1
a (A)
˚
29.7408(2)
8.2700(1)
14.7878(2)
90
6.0451(2)
8.3623(3)
9.3457(2)
114.959(1)
103.484(1)
91.557(1)
418.42(2)
1.407
29.4947(13)
9.8251(5)
13.1586(6)
90
29.3702(4)
9.6702(2)
13.3178(2)
90
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
94.715(1)
90
104.758(1)
90
105.353(1)
90
˚
3
V (A )
calc (g/cm )
3624.85(7)
1.534
3687.4(3)
1.594
3647.48(11)
1.480
3
d
Z
8
1
8
8
h
min/hmax
ꢀ38/38
ꢀ10/10
ꢀ19/19
1.410
ꢀ7/7
ꢀ33/33
ꢀ11/11
ꢀ15/15
1.391
ꢀ38/38
ꢀ12/12
ꢀ17/17
1.178
k
min/kmax
ꢀ10/10
ꢀ12/12
0.799
l
min/lmax
ꢀ1
l (mm
)
T
max/Tmin
0.85/0.69
36,385
8270
0.91/0.86
4332
1896
0.98/0.72
14,151
2925
0.82/0.65
18,531
4193
Refl. collected
Refl. unique
Refl. observed
Parameter
6723
407
1611
85
1833
218
3328
231
R(F)
0.029
0.037
0.043
0.033
2
(F )
R
w
0.067
0.098
0.068
0.079
2
S (Gof) on F
1.06
0.28
1.05
0.41
0.96
0.37
1.05
0.57
˚
ꢀ3
ꢀ3
)
(
(
Dq)max (e A
Dq)min (e A
)
˚
ꢀ0.44
ꢀ0.38
ꢀ0.31
ꢀ0.31

D.B. Werz et al. / Journal of Organometallic Chemistry 689 (2004) 3132–3142
3141
Table 4
Crystallographic data and details of the refinement procedure for 19, 21, (1,2)-22 and (1,2)-23
1
9
21
(1,2)-22
70Co
1017.19
(1,2)-23
70Co
981.16
Empirical formula
Formula mass (g/mol)
Crystal size (mm)
Crystal colour
C
1355.30
45
H
57
O
4
S
8
Cl
9
Co
2
C
1053.37
46
H
62
O
4
S
8
Co
2
C
53
H
O
2 4
S
4
C
50
H
2 4 4
O S
0.16 · 0.12 · 0.06
Yellow
0.40 · 0.26 · 0.02
Yellow
Plate
0.40 · 0.28 · 0.24
Yellow
Polyhedron
Orthorhombic
Pnma
0.30 · 0.18 · 0.13
Yellow
Crystal shape
Crystal system
Polyhedron
Triclinic
Polyhedron
Triclinic
Triclinic
ꢀ
ꢀ
ꢀ
Space group
˚
P1
P1
P1
a (A)
˚
14.3662(3)
14.9954(1)
16.7845(3)
115.819(1)
111.504(1)
92.278(1)
2941.23(8)
1.530
9.8456(2)
10.3022(1)
12.2588(2)
105.498(1)
94.444(1)
95.393(1)
1186.07(3)
1.475
14.1328(2)
24.4816(1)
14.8173(2)
90
9.9815(1)
10.0150(2)
13.2283(2)
75.588(1)
86.656(1)
70.014(1)
1203.10(3)
1.354
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
90
90
˚
3
V (A )
calc (g/cm )
5126.69(10)
1.318
3
d
Z
2
1
4
1
h
min/hmax
ꢀ15/15
ꢀ17/17
ꢀ17/17
1.296
ꢀ12/12
ꢀ13/13
ꢀ15/15
1.094
ꢀ18/18
ꢀ31/31
ꢀ19/19
0.853
ꢀ12/12
ꢀ12/12
ꢀ16/16
0.906
k
min/kmax
l
min/lmax
ꢀ1
l (mm
)
T
max./Tmin.
0.93/0.92
19,353
7189
0.98/0.67
12,285
5391
0.82/0.73
51,340
6014
0.89/0.77
11,415
4886
Refl. collected
Refl. unique
Refl. observed
Parameter
4043
642
4176
272
4696
314
3841
308
R(F)
0.057
0.034
0.035
0.041
2
(F )
R
w
0.107
0.074
0.091
0.098
2
S (Gof) on F
1.01
0.52
1.01
0.41
1.16
0.67
1.02
0.70
˚
ꢀ3
ꢀ3
)
(
(
Dq)max (e A
Dq)min (e A
)
˚
ꢀ0.46
ꢀ0.27
ꢀ0.38
ꢀ0.41
+
64 (4.28). HRMS (FAB ) C H S O Co : Calc.:
2
dichloromethane separated from the test solution by a
Haber–Luggin capillary. The E values reported for
chemically reversible systems were an average of the ob-
served anodic and cathodic peak potentials. A support-
ing electrolyte concentration of 0.1 M of [n-Bu N][PF ]
5
1
70
4
5
2
1
009.2848. Found: 1009.2828.
5
.3. X-ray crystallography and structure solution
4
6
The crystallographic data were recorded with a Bru-
ker Smart CCD diffractometer at 200(2) K at a wave-
was employed. The working electrode for cyclic voltam-
metry was a GC disk of 3 mm diameter. All measure-
ments were recorded with a scan rate of 100 and 200
˚
length k of 0.71073 A. Relevant crystal and data
ꢀ
1
collection parameters are given in Tables 3 and 4. Struc-
ture solution and refinement were carried out using
SHELXTL [27]. An empirical absorption correction was
carried out using SADABS [27] based on the Laue sym-
metry of the reciprocal space. Hydrogen atoms were in-
cluded at calculated positions. ORTEP drawings were
obtained by using ORTEP-3 for Windows program by
Farrugia [28]. In 17b and (1,2)-23 we found disorder be-
mV s . Samples were measured at a concentration of
ꢀ
1
1 mmol l in dichloromethane at room temperature.
Oxygen was removed by purging argon through the cell.
All potentials refer to the ferrocene/ferrocenium couple
as internal standard (0.0 mV), as recommended by IU-
PAC [29]. Referred to a saturated calomel electrode
(SCE) 460 mV have to be added for a solution of dichlo-
romethane [30].
tween S and CH moieties (4:1 and 3:1, respectively).
2
5
.4. Cyclic voltammetry
6. Supplementary material
The electrochemical measurements were performed
Crystallographic data for the structural analyses have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC Nos. 231117–231124 for com-
pound 13–15, 17b, 19, 21, (1,2)-22 and (1,2)-23. Copies
of this information may be obtained free of charge from:
with the potentiostat system PGSTAT20 (METR-
OHM). A traditional three-electrode, three-compart-
ment cell geometry was employed for voltammetry
experiments with a Ag/AgCl reference electrode in

3142
D.B. Werz et al. / Journal of Organometallic Chemistry 689 (2004) 3132–3142
The Director, CCDC, 12 Union Road, Cambridge CB2
EZ, UK, fax.(int code) +44(1223)336-033 or e-mail:
[12] (a) C. Benisch, S. Bethke, R. Gleiter, T. Oeser, H. Pritzkow, F.
Rominger, Eur. J. Org. Chem. (2000) 2479–2488;
1
(
b) D.B. Werz, R. Gleiter, F. Rominger, J. Org. Chem. 67 (2002)
290–4297;
c) J.H. Schulte, D.B. Werz, Frank Rominger, R. Gleiter, Org.
data_request@ccdc.cam.ac.uk or
cam.ac.uk.
http://www.ccdc.
4
(
Biomol. Chem. (2003) 2788–2794.
13] (a) R. Gleiter, D.B. Werz, B.J. Rausch, Chem. Eur. J. 9 (2003)
[
2
676–2683;
Acknowledgement
(
(
b) D.B. Werz, R. Gleiter, F. Rominger, J. Am. Chem. Soc. 124
2002) 10638–10639.
We are grateful to the Deutsche Forschungsge-
meinschaft, the Fonds der Chemischen Industrie and
BASF Aktiengesellschaft, Ludwigshafen, for financial
support. D.B. Werz is grateful to the Studienstiftung
des deutschen Volkes for a graduate fellowship. The
authors wish to thank T. Klippel, F.C. Liu, S. Korn-
mayer and Jens N a¨ gele for preparative assistance.
[
[
14] (a) D.B. Werz, R. Gleiter, F. Rominger, Organometallics 22
(2003) 843–849;
(
b) D.B. Werz, R. Gleiter, J. Org. Chem. 68 (2003) 9400–9405.
15] (a) C. Benisch, R. Gleiter, T.H. Staeb, B. Nuber, T. Oeser, H.
Pritzkow, F. Rominger, J. Organomet. Chem. 641 (2002) 102–
1
12;
b) C. Benisch, D.B. Werz, R. Gleiter, F. Rominger, T. Oeser,
(
Eur. J. Inorg. Chem. (2003) 1099–1112.
[
[
16] (a) H.D. Verkruijsse, L. Brandsma, Synthesis (1991) 818;
(
b) R.W. Gedridge Jr., L. Brandsma, R.A. Nissan, H.D.
Verkruijsse, S. Harder, R.L.P. de Jong, C.J. OꢀConnor, Organ-
ometallics 11 (1992) 418–422.
References
17] (a) R. Gleiter, D. Kratz, Acc. Chem. Res. 26 (1993) 311–318;
(b) R. Gleiter, M. Karcher, M.L. Ziegler, B. Nuber, Tetrahedron
Lett. 28 (1987) 195–198;
[
1] T.S. Piper, F.A. Cotton, G. Wilkinson, Inorg. Nucl. Chem. 1
1955) 165–174.
(
[
[
2] E.O. Fischer, R. Jira, Z. Naturforsch. Sect. B 10 (1955) 355.
3] (a) R.D.W. Kemmit, D.R. Russell, in: F.G.A. Stone, E.W. Abel
(c) R. Gleiter, M. Merger, Angew. Chem. 109 (1997) 2532–2546;
Angew. Chem. Int. Ed. Engl. 36 (1997) 2426–2439;
(d) R. Roers, F. Rominger, C. Braunweiler, R. Gleiter, Tetrahe-
dron Lett. 39 (1998) 7831–7834;
(
Eds.), Comprehensive Organometallic Chemistry, vol. 5, Perga-
mon Press, New York, 1982;
b) J.P. Collman, L.S. Hegedus, J.R. Norton, R.G. Finke,
(
(e) R. Roers, F. Rominger, R. Gleiter, Tetrahedron Lett. 40
(1999) 3141–3144;
Principles and Applications of Organotransition Metal Chemistry,
University Science Books, Mill Valley, CA, 1987.
4] (a) Reviews: A. Efraty, Chem. Rev. 77 (1977) 691–744;
(f) R.J. Schaller, G. Haberhauer, R. Gleiter, F. Rominger, Eur. J.
Inorg. Chem. (2002) 2296–2304.
[
[
(b) R. Gleiter, Angew. Chem. 104 (1992) 29–46;
Angew. Chem. Int. Ed. Engl. 31 (1992) 27–44.
[18] Recently, a CpCo-capped tetra-phosphorylcyclobutadiene com-
plex was synthesized: S. Sasaki, Y. Tanabe, M. Yoshifuji, Chem.
Commun. (2002) 1876–1877.
5] (a) Reviews: W.I. H u¨ bel, in: I. Wender, P. Pino (Eds.), Organic
Synthesis via Metal Carbonyls, vol. 1, Wiley, New York, 1968, p.
[19] J.R. Beck, J.A. Yahner, J. Org. Chem. 43 (1978) 2048–2052.
[20] I. Fleming, Frontier Orbitals and Organic Reactions, Wiley,
London, 1976 p. 122.
273;
(b) P. Pino, G. Braca, in: I. Wender, P. Pino (Eds.), Organic
Synthesis via Metal Carbonyls, vol. 2, 1977, p. 419.
6] N.E. Schore, Chem. Rev. 88 (1988) 1081–1119.
[21] R. Gleiter, H. Stahr, B. Nuber, Tetrahedron Lett. 36 (1995) 4607–
4610.
[
[
7] (a) Reviews: K.P.C. Vollhardt, Angew. Chem. 96 (1984) 525–541;
Angew. Chem. Int. Ed. Engl. 23 (1984) 539–555;
[22] P.E. Riley, R.E. Davis, J. Organomet. Chem. 113 (1976) 157–166.
[23] M.E. Peach, C. Burschka, Can. J. Chem. 60 (1982) 2029–2037.
[24] R. Gleiter, G. Pfl a¨ sterer, B. Nuber, J. Chem. Soc., Chem.
Commun. (1993) 454–456.
(
b) H. B o¨ nnemann, W. Brijoux, R. Brinkmann, W. Meurers, R.
Mynott, W. von Philipsborn, T. Egolf, J. Organomet. Chem. 272
1984) 231–249.
(
[25] J. Heinze, Angew. Chem. 96 (1984) 823–840;
Angew. Chem. Int. Ed. Engl. 23 (1984) 831–847.
[26] (a) W.P. Hart, D. Shihua, M.D. Rausch, J. Organomet. Chem.
282 (1985) 111–121;
[
[
8] (a) M.D. Rausch, G.F. Westover, E. Mintz, G.M. Reisner, I.
Bernal, A. Clearfield, J.M. Troup, Inorg. Chem. 18 (1979) 2605–
2615;
(b) J.H. Hardesty, J.B. Koerner, T.A. Albright, G.-Y. Lee, J.
Am. Chem. Soc. 121 (1999) 6055–6067.
9] (a) B. Jessel, Dissertation, Universit a¨ t Hamburg, 1984;
(b) M.D. Rausch, R.A. Genetti, J. Org. Chem. 35 (1970) 3888–
3897;
(c) E.W. Abel, S. Moorhouse, J. Organomet. Chem. 28 (1971)
211–215.
(b) A. Krebs, J. Wilke, Top. Curr. Chem. 109 (1983) 189–233.
[
[
10] C. Benisch, J. Ch a˜ vez, R. Gleiter, B. Nuber, H. Irngartinger, T.
Oeser, H. Pritzkow, F. Rominger, Eur. J. Inorg. Chem. (1998)
[27] G.M. Sheldrick, Bruker Analytical X-ray Division, Madison, WI,
1997.
[28] ORTEP-3 for Windows: A Version of ORTEP-III with a
629–632.
11] (a) R.G. Gastinger, M.D. Rausch, D.A. Sullivan, G.J. Palenik, J.
Am. Chem. Soc. 98 (1976) 719–723;
Graphical User Interface (GUI): L.J. Farrugia, J. Appl. Crystal-
logr. 30 (1997) 565.
(b) P.I. Dosa, G.L. Whitener, K.P.C. Vollhardt, A.D. Bond, S.J.
Teat, Org. Lett. 4 (2002) 2075–2078.
[29] G. Gritzner, J. K u˚ ta, Pure Appl. Chem. 56 (1984) 461–466.
[30] N.G. Connelly, W.E. Geiger, Chem. Rev. 96 (1996) 877–910.