(η5-Cyclopentadienyl)[η2-bis(tert-butylsulfonyl)acetylene](carbonyl)cobalt. An electrophilic reagent to yield CpCo-stabilized cyclobutadiene derivatives

Article abstract of DOI:10.1016/S0022-328X(01)01364-X

Various substituted (R=H, CH₃, SiMe₃, CO₂Me, COCH₃, EtMe₄) (R-η⁵-cyclopentadienyl)[η²-bis(tert-butylsulfonyl)acetylene](carbonyl)cobalt complexes (8-13) proved to be very reactiv

Full text of DOI:10.1016/S0022-328X(01)01364-X

Journal of Organometallic Chemistry 641 (2002) 102–112
www.elsevier.com/locate/jorganchem
(h5-Cyclopentadienyl)[h2-bis(tert-butylsulfonyl)acetylene]-
(carbonyl)cobalt
An electrophilic reagent to yield CpCo-stabilized cyclobutadiene
derivatives
Christoph Benisch a, Rolf Gleiter a,*, Tobias H. Staeb a, Bernhard Nuber b,
Thomas Oeser a, Hans Pritzkow b, Frank Rominger a
a Organisch-Chemisches Institut der Uni6ersita¨t Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany
b Anorganisch-Chemisches Institut der Uni6ersita¨t Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany
Received 15 June 2001
Dedicated to Professor Adolf Krebs on the occasion of his 70th birthday
Abstract
Various substituted (R=H, CH3, SiMe3, CO2Me, COCH3, EtMe4) (R-h5-cyclopentadienyl)[h2-bis(tert-butylsul-
fonyl)acetylene](carbonyl)cobalt complexes (8–13) proved to be very reactive towards alkynes under rather mild conditions.
Dithiaacetylenes reacted at room temperature, dialkyl- and diarylalkynes had to be heated to 80–90 °C to yield the corresponding
R-CpCo-stabilized cyclobutadiene complexes 18–37 and 39–42. X-ray investigations on 24–26, 30, 36 and 39–41 showed almost
equal CꢀC bond lengths in the cyclobutadiene rings. © 2002 Published by Elsevier Science B.V.
Keywords: Cyclobutadiene complexes; Alkynes; Cobalt complexes; Cyclization
1. Introduction
The first evidence for a stepwise mechanism was
reported by Lee and Brintzinger [7], who were able to
demonstrate by means of IR spectroscopy that on
irradiation of CpCo(CO)2 in presence of dipheny-
lacetylene, a complex with only one CO group must be
present.
Complex 1 was the first CpCo-complex with one CO
and one alkyne unit to be isolated. It was prepared by
Jessel and Krebs by reacting the highly strained alkyne
3,3,6,6-tetramethyl-1-thiacycloheptyne with CpCo(CO)2
[8]. Reactions of 1 with various alkynes (Scheme 1)
demonstrated that the remaining CO unit in 1 could be
replaced thermally or photochemically. With few excep-
tions the product of these reactions was always the
corresponding cyclobutadiene complex as indicated in
Scheme 1.
Since the first synthesis of dicarbonyl(h5-cyclopenta-
dienyl)cobalt [CpCo(CO)2] in 1955 [1,2], this compound
has played a major role in organocobalt chemistry [3].
Among others, the reactions of CpCo(CO)2 with alky-
nes have been investigated intensively [3], because a
number of useful molecules can be prepared in a
straight forward fashion. By this way CpCo-complexes
of cyclobutadienes [4], cyclopentadienones [5] and ben-
zoquinones have been prepared; the trimerization of
alkynes [6] has also been achieved. The disadvantage of
the metal supported oligomerization of alkynes is that,
for unsymmetrical substituted alkynes always isomers
are produced. This obstacle might overcome if
oligomerization could be carried out in stepwise
fashion.
In our studies, on the reactivity of electron poor
alkynes, we were able to isolate stable monoalkyne
complexes by reaction of CpCo(CO)2 and bis(tert-
butylsulfonyl)acetylene (BTSA) [9] in methylene chlo-
* Corresponding author. Tel.: +49-6221-548400; fax: +49-6221-
544205.
E-mail address: rolf.gleiter@urz.uni-heidelberg.de (R. Gleiter).
0022-328X/02/$ - see front matter © 2002 Published by Elsevier Science B.V.
PII: S0022-328X(01)01364-X

C. Benisch et al. / Journal of Organometallic Chemistry 641 (2002) 102–112
103
Table 2
Yields (% in italics) of the push-pull-cyclobutadiene complexes 18–37
ride at room temperature (Scheme 2) [10]. This reaction
could also be extended to substituted RꢀCpCo(CO)2
complexes as shown in Scheme 2. A comparison of the
results obtained by spectroscopic studies of 1 and 8
(Table 1) [8,10] indicates a stronger bonding of the
R2
R1
H
Me
SiMe3
CO2Me
Ac
EtMe4
n-Bu
Ph
18
73
19
69
20
78
21
49
22
53
23
37
24
25
26
27
28
29
56
65
62
42
46
26
Mes
t-Bu
30
65
–
–
31
13
–
–
32
41
–
0
33
34
35
36
37
–
10
31
13
15
17
0
Obtained from the reactions of 8–13 with the dithiaalkynes 14–17.
(For the meaning of R1 and R2, see Schemes 2 and 3).
alkyne unit and a weaker bonding of the CO group in
8 as compared to 1. This suggested a higher reactivity
towards alkynes, especially electron rich ones, in the
case of 8 as compared to 1. Because 8–13 are easily
available and the tert-butylsulfonyl groups of resulting
1,2-bis(tert-butylsulfonyl)cyclobutadiene derivatives are
prone to further replacement reactions, we undertook
studies with various alkynes to explore the scope and
limitations of a replacement of CO in 8–13 by triple
bonds.
Scheme 1.
2. Results
2.1. Acetylenedithioethers
As starting materials for electron rich alkynes we
used acetylene dithioethers because these substances are
stable, and readily available [11–13]. The reactions of
8–13 with an excess of the acetylene dithioethers 14–17
were carried out in toluene, mostly at room tempera-
ture (Scheme 3). In the case of 17, the reaction was
carried out at 90 °C. The yields of the resulting donor–
acceptor cyclobutadiene complexes are summarized in
Table 2. The yellow colored substances are remarkably
stable. They are inert towards moisture and air. The
tolerance towards steric repulsion in the CpCo-stabi-
lized cyclobutadiene complexes is relatively high, only
in the cases in which reaction was attempted between
13 and 16 or 17, no reaction products could be
detected.
Scheme 2.
Table 1
Comparison of the spectroscopic data of 1 and 8
1
8
13C l (CꢁC)
77.92
93.72
w(CꢁC) (cm−1
)
1880
1975
1772
2017
w(CO) (cm−1
)
The investigations of the 13C-NMR spectra reveal
chemical shifts of the carbon signals of the cyclobutadi-
ene ring adjacent to the SO2-groups between l=76.1
and 82.3. For the corresponding carbon atoms adjacent
to the sulfur atoms we encounter signals between l=
78.1 and 87.0.
Scheme 3.

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C. Benisch et al. / Journal of Organometallic Chemistry 641 (2002) 102–112
2.2. Further alkynes
To probe which kind of alkynes can replace the CO
groups, further we studied reactions of 8–10 with
tolane (38) and in part with cyclooctyne (43) (Scheme
4) to afford the corresponding cyclobutadiene products
39–42 in yields between 36 (41) and 60–75% as orange
colored solids. The reaction had to be carried out at
80 °C in toluene, indicating less reactivity for 38 and 43
as compared to 14–16.
3. Structural investigations
Of the 24 products (18–37 and 39–42) obtained from
the reactions of 8–13, 38 and 43 with the dithialkynes
14–17, the products 24–26, 30, 36 and 39–41 yielded
single crystals which could be investigated by X-ray
diffraction. As examples, we show in Fig. 1, the molec-
ular structures of 24, 26, 36 and 39. The conformations
of 24 and 25 in the solid state are similar. In both
structures one phenyl group directs away from the
metal, whereas the other phenyl–thio substituent is
situated approximately in the plane of the cyclobutadi-
ene ring. Both tert-butyl groups point away from the
metal. In 26 both phenyl groups are directed away from
the metal probably due to the bulky SiMe3 group. Since
in 26 both tert-butyl groups also point in the same
direction as the phenyl groups, we expect considerable
steric interactions in the space below the cyclobutadiene
ring (see below). In the case of 36 (Fig. 1) two diago-
nally situated tert-butyl groups point below the plane
of the cyclobutadiene ring, one above the plane,
whereas the fourth is situated approximately in the
plane of the cyclobutadiene ring. In 30 one mesityl
group is directed towards the Cp ring, whereas the
other three bulky groups point away from the metal. In
39–41 the tert-butylsulfonyl groups are pointing away
from the metal, and the phenyl rings are twisted around
Fig. 1. ORTEP drawing of 24, 26, 36 and 39. The heteroatoms are
labeled, the H atoms have been omitted for the sake of clarity.
Ellipsoids are at the 50% probability level.
Scheme 4.

C. Benisch et al. / Journal of Organometallic Chemistry 641 (2002) 102–112
105
Table 3
Selected distances (pm) and interplanar angles (°) of 24–26, 30, 36 and 39–41
a
Compound
d(CoꢀCp)
d(CoꢀCbd) a
†(CpꢀCbd)
a b
b b
c b
24
25
26
30
36
39
40
41
166
166
166
166
168
166
166
167
166
167
167
167
168
167
168
168
1.2
2.9
5.5
2.9
8.4
1.3
3.5
2.1
146
144
146
147
148
146
146
145
148
147
148
148
147
149
149
149
146
146
147
148
148
147
147
147
147
147
147
147
146
147
147
148
a Distances from the metal to the center of the corresponding rings.
b For the definition of a, b, c see Scheme 3.
4. Conclusion
the connecting CꢀC bonds. The relatively small methyl
group of the methyl-cyclopentadienyl ligand is found to
point in 40 towards the SO2-groups, whereas in 41 the
bulky Si(CH3)3 substituent points towards the phenyl
groups. In comparison to 40 this reduces the strain
energy within 41, which allows both planes of the Cp-
and Cbd-rings to be almost parallel in 41 as shown in
Table 3. In Table 3 we have compared the most rele-
vant bond lengths and angles of 24–26, 30, 36 and
39–41. An examination of the cyclobutadiene rings in
the molecules 24–26, 30 and 36 shows very similar
bond lengths on all four sides. There is no indication of
bond alternation in the four-membered ring due to a
donor–acceptor interaction. We notice that the bond
lengths b between the tert-butylsulfonyl groups are
slightly longer (147–148 pm) than a and c (Scheme 3).
This lengthening we ascribe to repulsions between the
adjacent bulky tert-butylsulfonyl groups. An indication
of steric repulsion is also encountered if we consider the
angle between the planes of the cyclopentadienyl and
the cyclobutadiene rings. Both planes are almost paral-
lel in 24, whereas in all other structures there is a
deviation by 3–8°. The most pronounced deviation
occurs in 26 and 36, for which relatively large sub-
stituents on the Cp ring interfere with bulky groups on
the cyclobutadiene moiety of the molecule. A compari-
son with the structural data of other CpCo–cyclobuta-
diene complexes, such as 44–47 [14–17] reveals very
similar bond lengths for the CpꢀCo and CbdꢀCo dis-
tance and for the distances within the cyclobutadiene
rings (Table 4) as found in our cases. This supports our
statement that there is no indication of a donor–accep-
tor influence in our samples.
We have shown that the CO group in complexes
8–13 can be replaced by electron rich as well as alkyl
and phenyl substituted alkynes to yield the correspond-
ing CpCo-stabilized cyclobutadiene complexes. This re-
action opens a convenient and simple route to a new
class of formally donor–acceptor substituted cyclobuta-
diene complexes, which are stable at room temperature
and resistant to water and oxygen. The X-ray studies
reveal almost equal CꢀC-distances within the cyclobu-
tadiene rings.
5. Experimental
5.1. General methods
Moisture- and oxygen-sensitive reactions were con-
ducted in oven-dried glassware under Argon. Toluene
was dried with sodium-benzophenone and distilled un-
der Ar before use; petroleum ether and Et2O were
distilled before use. M.p. are uncorrected. Materials
Table 4
Selected distances (pm) of 44–47
a
Compound d(CoꢀCp)
d(CoꢀCbd) a
d(CꢀC)(Cbd) b
(pm)
(pm)
(pm)
44 [14]
45 [15]
46 [16]
166
167
167
168
169
169
144
145
147
146
147
147
47 [17]
169
170
146
147
146
146
a Distances from the metal to the center of the corresponding rings.
Formula 1
b Average CꢀC bond lengths of the cyclobutadiene rings.

106
C. Benisch et al. / Journal of Organometallic Chemistry 641 (2002) 102–112
used for column chromatography: silica gel 60 (Mach-
3H, CpꢀCH3), 2.98 (m, 4H, SCH2), 5.16/5.29 (pt, 4H,
CpꢀH). — 13C-NMR (50 MHz, CDCl3): l=12.77
(CpꢀCH3), 14.4 (CH2CH3), 22.7 (CH2CH3), 25.2
(C(CH3)3), 32.0 (SCH2CH2), 37.0 (SCH2), 62.0
(C(CH3)3), 76.9 (C(CBD)ꢀSO2tBu), 84.5 (C(CBD)ꢀ
SnBu), 84.9/86.5 (CpCꢀH), 100.6 (CpCꢀCH3). — IR
1
ery–Nagel). H- and 13C-NMR: Bruker AS 200 (1H at
200 MHz and 13C at 50.33 MHz), Bruker Avance 300
(1H at 300 MHz and 13C at 75.47 MHz), Bruker
Avance 500 (1H at 500 MHz and 13C at 125.77 MHz)
using the solvent as internal standard. IR: Bruker Vec-
tor 22 FT–IR. MS: low resolution: ZAB-2F; high
resolution: JEOL JMS-700. Elemental analyses were
carried out by the Mikroanalytisches Laboratorium der
Universita¨t Heidelberg. The complexes 8–13 and the
bis(arylthio)-–bis(alkylthio)acetylenes 14–17 were pre-
pared according to literature methods. Tolane (38) was
purchased from Acros and recrystallized from EtOH
before use. Cyclooctyne was prepared according to
literature procedure [18].
(film):
w˜ =2961, 2872, 1461, 1352, 1310 cm−1. —
UV–vis (CH2Cl2): umax (log m)=252 (4.26), 316 (4.11),
354 nm (3.45). — MS (EI+): 606 [M+], 485, 352,
259. — HRMS (FAB+) C26H43CoO4S4: Calc.:
606.1376; Found: 606.1384%.
5.2.3. (p5-Trimethylsilylcyclopentadienyl)[p4-1,2-
bis(tert-butylsulfonyl)-3,4-bis(n-butylthio)cyclo-
butadiene]cobalt(I) (20)
5.2. General procedure for the preparation of the
cyclobutadiene complexes 18–37 and 39–42
Starting material: 245 mg (0.50 mmol) of
Me3SiCpCo(CO)(BTSA) (10) and 121 mg (0.60 mmol)
of bis(n-butylthio)acetylene (14). Yield: 259 mg (78%)
of 20 as a orange oil. — 1H-NMR (300 MHz, CDCl3):
The appropriate monoalkynecobalt complex is dis-
solved in 60 ml of C6H5CH3 and the alkyne is added in
one portion. The reaction mixture is stirred at room
temperature (18–32), at 90 °C (33–37) or at 80 °C
(39–42). After completion of the reaction, the solvent is
removed by rotary evaporation and the crude product
is purified by column chromatography (SiO2, petroleum
ether–Et2O 1:1).
3
l=0.33 (s, 9H, Si(CH3)3), 0.91 (t, 6H, CH2CH3, J=
7.3 Hz), 1.45 (m, 4H, CH2CH3), 1.46 (s, 18H C(CH3)3),
1.60 (m, 4H, SCH2CH2), 2.95 (m, 4H, SCH2), 5.24/5.73
(pt, 4H, CpꢀH). — 13C-NMR (50 MHz, CDCl3): l=
0.3 (Si(CH3)3), 14.4 (CH2CH3), 22.7 (CH2CH3), 25.3
(C(CH3)3), 32.0 (SCH2CH2), 37.5 (SCH2), 62.2
(C(CH3)3), 76.6 (C(CBD)ꢀSO2tBu), 85.6 (C(CBD)ꢀ
SnBu), 88.8/90.0 (CpCꢀH), 94.2 (CpCꢀSiMe3). — IR
(film): w˜ =2959, 2931, 2873, 1463, 1314, 1121, 841,
704, 544 cm−1. — UV–vis (CH2Cl2): umax (log m)=
258 (4.17), 320 (4.08), 366 nm (3.42). — HRMS
(FAB+) [M+] C28H49CoO4S4Si: Calc.: 664.1615;
Found: 664.1588%.
5.2.1. (p5-Cyclopentadienyl)-[p4-1,2-bis(tert-butyl-
sulfonyl)-3,4-bis(n-butylthio)cyclobutadiene]cobalt(I)
(18)
Starting material: 252 mg (0.60 mmol) of Cp-
Co(CO)(BTSA) (8) and 121 mg (0.60 mmol) of bis(n-
butylthio)acetylene (14). Yield: 261 mg (73%) of 18 as a
yellow solid, m.p. 70 °C. — 1H-NMR (300 MHz,
3
CDCl3): l=0.94 (t, 6H, CH2CH3, J=7.3 Hz), 1.44
5.2.4. (p5-Methoxycarbonylcyclopentadienyl)[p4-1,2-
bis(tert-butylsulfonyl)-3,4-bis(n-butylthio)cyclo-
butadiene]cobalt(I) (21)
(m, 4H, CH2CH3), 1.45 (s, 18H, C(CH3)3), 1.62 (m, 4H,
SCH2CH2), 3.02 (m, 4H, SCH2), 5.37 (s, 5H,
CpꢀH). — 13C-NMR (50 MHz, CDCl3): l=14.4
(CH2CH3), 22.7 (CH2CH3), 25.1 (C(CH3)3), 31.9
(SCH2CH2), 37.5 (SCH2), 62.0 (C(CH3)3), 77.5
Starting material: 238 mg (0.50 mmol) of
CpCO2MeCo(CO)(BTSA) (11) and 101 mg (0.50 mmol)
of bis(n-butylthio)acetylene (14). Yield: 160 mg (49%)
of 21 as a orange oil. — 1H-NMR (300 MHz, CDCl3):
(C(CBD)ꢀSO2tBu),
85.7
(C(CBD)ꢀSnBu),
85.9
3
(CpꢀC). — IR (KBr): w˜ =2959, 2929, 2868, 1420,
1309 cm−1. — UV–vis (CH2Cl2): umax (log m)=246
(4.24), 314 (4.02), 356 nm (3.53). — HRMS (FAB+)
C25H41CoO4S4: Calc.: 592.1220; Found: 592.1232%.
l=0.95 (t, 6H, CH2CH3, J=7.3 Hz), 1.44 (m, 4H,
CH2CH3), 1.45 (s, 18H, C(CH3)3), 1.60 (m, 4H,
SCH2CH2), 3.06 (m, 4H, SCH2), 3.87 (s, 3H, CO2CH3),
5.63/5.78 (pt, 4H, CpꢀH). — 13C-NMR (50 MHz,
CDCl3): l=14.4 (CH2CH3), 22.7 (CH2CH3), 25.1
(C(CH3)3), 32.0 (SCH2CH2), 36.0 (SCH2), 52.7
(CO2CH3), 62.4 (C(CH3)3), 77.8 (C(CBD)ꢀSO2tBu),
87.0 (C(CBD)ꢀSnBu), 86.9/88.7 (CpCꢀH), 90.7
(CpCꢀCO2Me), 166.1 (CO2CH3). — IR (film): w˜ =
5.2.2. (p5-Methylcyclopentadienyl)-[p4-1,2-bis(tert-
butylsulfonyl)-3,4-bis(n-butylthio)cyclobutadiene]-
cobalt(I) (19)
Starting material: 260 mg (0.60 mmol) of MeCp-
Co(CO)(BTSA) (9) and 121 mg (0.06 mmol) of bis(n-
butylthio)acetylene (14). Yield: 251 mg (69%) of 19 as a
orange oil. — 1H-NMR (500 MHz, CDCl3): l=0.94
2960, 1725, 1470, 1312, 1194 cm−1
. — UV–vis
(CH2Cl2): umax (log m)=240 (4.45), 322 (4.15), 366 nm
(3.69). — MS (FAB+): 650 [M+], 577. — HRMS
(FAB+) [M+] C27H43CoO6S4: Calc.: 650.1275; Found:
650.1280%.
3
(t, 6H, CH2CH3, J=7.3 Hz), 1.42 (m, 4H, CH2CH3),
1.44 (s, 18H, C(CH3)3), 163 (m, 4H, SCH2CH2), 2.09 (s,

C. Benisch et al. / Journal of Organometallic Chemistry 641 (2002) 102–112
107
5.2.5. (p5-Acetylcyclopentadienyl)-[p4-1,2-bis(tert-
butylsulfonyl)-3,4-bis(n-butylthio)cyclobutadiene]-
cobalt(I) (22)
Cl2): umax (log m)=248 (4.44), 296 nm (4.04). —
HRMS (EI+) C29H33CoO4S4: Calc.: 632.0594;
Found: 632.0589%. — C29H33CoO4S4 (632.1): Calc.:
C, 55.05; H, 5.26; S, 20.27. Found: C, 54.98; H, 5.35; S,
20.00%.
Starting material: 240 mg (0.52 mmol) of AcCp-
Co(CO)(BTSA) (12) and 105 mg (0.52 mmol) of bis(n-
butylthio)acetylene (14). Yield: 174 mg (53%) of 22 as a
orange oil. — 1H-NMR (300 MHz, CDCl3): l=0.94
5.2.8. (p5-Methylcyclobutadienyl)-(p4-1,2-bis(tert-butyl-
sulfonyl)-3,4-bis(phenylthio)cyclobutadiene]cobalt(I) (25)
Starting material: 238 mg (0.55 mmol) of CpMe-
Co(CO)(BTSA) (9) and 160 mg (0.66 mmol) of
bis(phenylthio)acetylene (15). Yield: 231 mg (65%) of
25 as a orange solid, m.p. 180 °C. — 1H-NMR (300
MHz, CDCl3): l=1.41 (s, 18H, C(CH3)3), 2.14 (s, 3H,
CpꢀCH3), 5.02/5.25 (pt, 4H, CpꢀH), 7.21 (m, 10H,
PhꢀH). — 13C-NMR (75 MHz, CDCl3): l=12.9
(CpꢀCH3), 25.2 (C(CH3)3), 62.1 (C(CH3)3), 80.4
(C(CBD)ꢀSO2tBu), 81.0 (C(CBD)ꢀSPh), 86.2/87.3
(CpꢀCꢀH), 101.8 (CpꢀCꢀCH3), 127.9 (PhꢀCpara), 129.3/
130.9 (PhꢀCortho/meta), 135.4 (PhꢀCꢀS). — IR (KBr):
3
(t, 6H, CH2CH3, J=7.3 Hz), 1.43 (s, 18H, C(CH3)3),
1.44 (m, 4H, CH2CH3), 1.60 (m, 4H, SCH2CH2), 2.50
(s, 3H, C(O)CH3), 3.03 (m, 4H, SCH2), 5.64/5.85 (pt,
4H, CpꢀH). — 13C-NMR (50 MHz, CDCl3): l=14.4
(CH2CH3) 22.7 (CH2CH3), 25.1 (C(CH3)3), 29.4
(C(O)CH3), 32.0 (SCH2CH2), 36.1 (SCH2), 62.4
(C(CH3)3), 78.1 (C(CBD)ꢀSO2tBu), 86.9 (C(CBD)ꢀ
SnBu), 86.3/88.7 (CpCꢀH), 97.0 (CpCꢀCO2Me), 197.7
(C(O)CH3). — IR (film): w˜ =2962, 2932, 1682, 1460,
1312 cm−1. — UV–vis (CH2Cl2): umax (log m)=246
(4.38), 326 (4.12), 366 nm (3.60). — MS (FAB+): 635
[M+H+],
561. — HRMS
(FAB+)
[M+]
C27H43CoO5S4: Calc.: 634.1325; Found: 634.2152%.
w˜ =3050, 2988, 2929, 1579, 1477, 1355, 1304 cm−1
.
— UV–vis (CH2Cl2): umax (log m)=250 (4.37), 300 nm
(4.01). — HRMS (EI+): [M+] C30H35CoO4S4: Calc.:
646.0750; Found: 646.0766%. C30H35CoO4S4 (646.1):
Calc.: C, 55.71; H, 5.45; S, 19.83. Found: C, 55.67; H,
5.52; S, 19.63%.
5.2.6. (p5-1-Ethyl-2,3,4,5-tetramethylcyclopentadienyl)-
[p4-1,2-bis(tert-butylsulfonyl)-3,4-bis(n-butylthio)-
cyclobutadiene]cobalt(I) (23)
Starting material: 251 mg (0.50 mmol) of
EtMe4CpCo(CO)(BTSA) (13) and 121 mg (0.60 mmol)
of bis(n-butylthio)acetylene (14). Yield: 125 mg (37%)
of 23 as a yellow solid, m.p. 84 °C. — 1H-NMR (300
5.2.9. (p5-Trimethylsilylcyclopentadienyl)-
[p4-1,2-bis(tert-butylsulfonyl)-3,4-bis(phenylthio)-
cyclobutadiene]cobalt(I) (26)
3
MHz, CDCl3): l=0.92 (t, 6H, CH2CH3, J=7.3 Hz),
1.40 (s, 18H, C(CH3)3), 1.40 (m, 4H, CH2CH2CH3),
1.60 (m, 4H, SCH2CH2), 1.91/1.93 (s, 12H, CpꢀCH3),
2.50 (q, 2H, CpꢀCH2CH3), 2.78 (m, 4H, SCH2). —
13C-NMR (75 MHz, CDCl3): l=10.0/10.2 (CpꢀCH3),
14.4 (CH2CH3), 18.4 (CpꢀCH2CH3), 22.9 (CH2CH3),
25.7 (C(CH3)3), 32.1 (SCH2CH2), 36.8 (SCH2), 62.3
(C(CH3)3), 76.1 (C(CBD)ꢀSO2tBu), 79.4 (C(CBD)ꢀ
SnBu), 95.4/96.4 (CpCꢀCH3), 100.7 (CpCꢀCH2-
Starting material: 245 mg (0.50 mmol) of
CpSiMe3Co(CO)(BTSA) (10) and 145 mg (0.60 mmol)
of bis(phenylthio)acetylene (15). Yield. 217 mg (62%) of
26 as a orange solid, m.p. 137 °C. — 1H-NMR (500
MHz, CDCl3): l=0.35 (s, 9H, Si(CH3)3), 1.38 (s, 18H,
C8CH3)3), 4.96/5.77 (pt, 4H, CpꢀH), 7.15 (m, 10H,
PhꢀH). — 13C-NMR (125 MHz, CDCl3): l=0.4
(Si(CH3)3), 25.2 (C(CH3)3), 62.3 (C(CH3)3), 80.5
(C(CBD)ꢀSO2tBu), 82.1 (C(CBD)ꢀSPh), 89.7/91.5
(CpꢀCꢀH), 95.2 (CpꢀCꢀSiMe3), 127.9 (PhꢀCpara), 129/
130.9 (PhꢀCortho/meta), 135.9 (PhꢀCꢀS). — IR (KBr):
w˜ =2955, 1581, 1477, 1310 cm−1. — UV–vis (CH2-
Cl2): umax (log m)=248 (4.30), 300 nm (4.01). —
HRMS (FAB+) C32H41CoO4S4Si: Calc.: 704.0989;
Found: 704.0982%. C32H41CoO4S4Si (704.1): Calc.: C,
54.52; H, 5.86; S, 18.19. Found: C, 54.51; H, 6.02; S,
18.04%.
CH3). — IR
(film):
w˜ =2960, 2929, 1458,
1360 cm−1. — UV–vis (CH2Cl2) umax (log m)=266
(4.01), 322 (4.04), 360 nm (3.20). — HRMS (EI+):
[M+] C31H53CoO4S4: Calc.: 676.2159; Found:
676.2152%.
5.2.7. (p5-Cyclopentadienyl)-[p4-1,2-bis(tert-butyl-
sulfonyl)-3,4-bis(phenylthio)cyclobutadiene]cobalt(I) (24)
Starting material: 230 mg (0.55 mmol) of Cp-
Co(CO)(BTSA) (8) and 160 mg (0.66 mmol) of
bis(phenylthio)acetylene (15). Yield: 196 mg (56%) of
24 as a orange solid, m.p. 186 °C. — 1H-NMR (300
MHz, CDCl3): l=1.47 (s, 18H, C(CH3)3), 5.28 (s, 5H,
CpꢀH), 7.30 (m, 10H, PhꢀH). — 13C-NMR (75 MHz,
CDCl3): l=25.1 (C(CH3)3), 62.1 (C(CH3)3), 80.9
(C(CBD)ꢀSO2tBu), 82.5 (C(CBD)ꢀSPh), 87.0 (CpꢀC),
128.2 (PhꢀCpara), 129.4/131.1 (PhꢀCortho/meta), 135.7
5.2.10. (p5-Methoxycarbonylcyclopentadienyl)-
[p4-1,2-bis(tert-butylsulfonyl)-3,4-bis(phenylthio)cyclo-
butadiene]cobalt(I) (27)
Starting material: 238 mg (0.50 mmol) of
CpCO2MeCo(CO)(BTSA) (11) and 145 mg (0.60 mmol)
of bis(phenylthio)acetylene (15). Yield: 161 mg (42%) of
27 as a yellow solid, m.p. 125 °C. — 1H-NMR (500
MHz, CDCl3): l=1.41 (s, 18H, C(CH3)3), 3.93 (s, 3H,
CO2CH3), 5.63/5.72 (pt, 4H, CpꢀH), 7.10 (m, 10H,
(PhꢀCꢀS). — IR
(KBr):
w˜ =2982, 1478, 1308,
(CH2-
1121, 827, 718, 692, 554 cm−1. — UV–vis

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C. Benisch et al. / Journal of Organometallic Chemistry 641 (2002) 102–112
5.2.13. (p5-Cyclopentadienyl)-[p4-1,2-bis(tert-butyl-
sulfonyl)-3,4-bis(mesitylthio)cyclobutadiene]cobalt(I)
(30)
PhꢀH). — 13C-NMR (125 MHz, CDCl3): l=25.0
(C(CH3)3), 52.9 (CO2CH3), 62.5 (C(CH3)3), 80.7
(C(CBD)ꢀSO2tBu), 83.3 (C(CBD)ꢀSPh), 88.4/89.4
(CpꢀCꢀH), 91.1 (CpꢀCꢀCO2Me), 128.2 (PhꢀCpara),
129.3/131.1 (PhꢀCortho/meta), 133.4 (PhꢀCꢀS), 165.5
Starting material: 230 mg (0.55 mmol) of Cp-
Co(CO)(BTSA) (8) and 180 mg (0.55 mmol) of bis(me-
sitylthio)acetylene (16). Yield: 258 mg (65%) of 30 as a
yellow solid, m.p. 218 °C. — 1H-NMR (300 MHz,
CDCl3): l=1.28 (s, 18H, C(CH3)3), 2.28 (s, 6H,
PhꢀCH3), 2.64 (12H, PhꢀCH3), 4.99 (s, 5H, CpꢀH),
6.91 (s, 4H, PhꢀH). — 13C-NMR (125 MHz, CDCl3):
l=21.4 (PhꢀCH3(para)), 23.4 PhꢀCH3(ortho)), 25.0
(C(CH3)3), 62.3 (C(CH3)3), 81.1 (C(CBD)ꢀSO2tBu),
85.3 (C(CBD)ꢀSMes), 86.5 (CpꢀC), 129.5 (PhꢀCmeta),
131.5 (PhCꢀS), 139.5 (PhꢀCpara), 143.4 (PhꢀCortho). —
IR (KBr): w˜ =3124, 2967, 2922, 1460 cm−1. —
UV–vis (CH2Cl2): umax (log m)=252 (4.29), 300 (3.93),
324 nm (3.82). — HRMS (FAB+): C35H45CoO4S4:
Calc.: 716.1533; Found: 716.1531%.
(CO2Me). — IR
(KBr):
w˜ =2949, 1726, 1474,
(CH2Cl2): umax
1308, 1285 cm−1. — UV–vis
(log m)=246 (4.45), 306 nm (4.03). — HRMS
(FAB+) C31H35CoO6S4: Calc.: 690.0649; Found:
690.0690%. — C31H35CoO6S4 (690.0): Calc.: C, 53.90;
H, 5.11; S, 18.57. Found: C, 53.98; H, 5.20; S, 18.56%.
5.2.11. (p5-Acetylcyclopentadienyl)-[p4-1,2-bis(tert-
butylsulfonyl)-3,4-bis(phenylthio)cyclobutadiene]cobalt(I)
(28)
Starting material: 230 mg (0.50 mmol) of AcCp-
Co(CO)(BTSA) (12) and 145 mg (0.60 mmol) of
bis(phenylthio)acetylene (15). Yield: 157 mg (46%) of
28 as a orange solid, m.p. 138 °C. — 1H-NMR (300
MHz, CDCl3): l=1.39 (s, 18H, C(CH3)3), 2.57 (s, 3H,
C(O)CH3), 5.62/5.71 (pt, 4H, CpꢀH), 7.11 (m, 10H,
PhꢀH). — 13C-NMR (75 MHz, CDCl3): l=25.1
(C(CH3)3), 29.5 (C(O)CH3), 62.5 (C(CH3)3), 80.9
(C(CBD)ꢀSO2tBu), 83.1 (C(CBD)ꢀSPh), 87.5/89.6
(CpꢀCꢀH), 97.2 (CpꢀCꢀAc), 128.3 (PhꢀCpara), 129.3/
5.2.14. (p5-Trimethylsilylcyclopentadienyl)-[p4-1,2-bis-
(tert-butylsulfonyl)-3,4-bis(mesitylthio)cyclobutadiene]-
cobalt(I) (31)
Starting material: 245 mg (0.50 mmol) of
CpSiMe3Co(CO)(BTSA) (10) and 163 mg (0.50 mmol)
of bis(mesitylthio)acetylene (16). Yield: 50 mg (13%) of
31 as a yellow solid, m.p. 195 °C. — 1H-NMR (500
MHz, CDCl3): l=0.23 (s, 9H, Si(CH3)3), 1.22 (s, 18H,
C(CH3)3), 2.27 (s, 6H, PhꢀCH3), 2.67 12H, PhꢀCH3),
4.59/5.45 (pt, 4H, CpꢀH), 6.91 (s, 4H, PhꢀH). — 13C-
NMR (50 MHz, CDCl3): l= −0.03 (Si(CH3)3), 21.6
(PhꢀCH3(para)), 24.3 (PhꢀCH3(ortho)), 25.4 (C(CH3)3),
62.8 (C(CH3)3), 81.8 (C(CBD)ꢀSO2tBu), 85.2
131.3
(C(O)Me). — IR
(PhꢀCortho/meta),
133.1
(KBr):
(PhꢀCꢀS),
197.0
w˜ =2971, 1681,
1309 cm−1. — UV–vis (CH2Cl2): umax (log m)=246
(4.42), 308 nm (4.04). — HRMS (FAB+) [M+]
C31H35CoO5S4: Calc.: 674.0699; Found: 674.0711%. —
C31H35CoO5S4 (674.8): Calc.: C, 55.18; H, 5.23; S,
19.01. Found: C, 55.04; H, 5.20; S, 18.95%.
(C(CBD)ꢀSMes),
88.6/91.3
(CpCꢀH),
95.7
(CpCꢀSiMe3), 129.9 (PhCmeta), 132.7 (PhCꢀS), 139.8
(PhCpara), 144.0 (PhCortho). — IR (KBr): w˜ =
2955, 1462, 1309 cm−1. — UV–vis (CH2Cl2): umax
(log m)=264 (4.20), 314 (3.81), 366 nm (3.27). —
HRMS (FAB+) [M+H+] C38H54CoO4S4Si: Calc.:
789.2006; Found: 789.2021%.
5.2.12. (p5-1-Ethyl-2,3,4,5-tetramethylcyclopenta-
dienyl)[p4-1,2-bis(tert-butylsulfonyl)-3,4-bis(phenylthio)-
cyclobutadiene]cobalt(I) (29)
Starting material: 231 mg (0.46 mmol) of
EtMe4CpCo(CO)(BTSA) (13) and 134 mg (0.55 mmol)
of bis(phenylthio)acetylene (15). Yield: 85 mg (26%) of
29 as a yellow solid, m.p. 161 °C. — 1H-NMR (300
5.2.15. (p5-Acetylcyclopentadienyl)-[p4-1,2-bis-
(tert-butylsulfonyl)-3,4-bis(mesitylthio)cyclobutadiene]-
cobalt(I) (32)
3
MHz, CDCl3): l=1.04 (t, 3H, CH2CH3, J=7.6 Hz),
1.29 (s, 18H, C(CH3)3), 2.03/2.04 (s, 12H, CpꢀCH3),
2.63 (q, 2H, CH2CH3, 3J=7.6 Hz), 6.95 (m, 10H,
PhꢀH). — 13C-NMR (75 MHz, CDCl3): l=10.0/10.3
(CpꢀCH3), 14.3 (CH2CH3), 18.3 (CH2CH3), 25.5
(C(CH3)3), 62.4 (C(CH3)3), 76.1 (C(CBD)ꢀSO2tBu),
78.1 (C(CBD)ꢀSPh), 96.1/97.2 (CpCꢀCH3), 101.2
Starting material: 85 mg (0.18 mmol) of AcCp-
Co(CO)(BTSA) (12) and 60 mg (0.18 mmol) of bis(me-
sitylthio)acetylene (16). Yield: 56 mg (41%) of 32 as a
yellow solid, m.p. 219 °C. — 1H-NMR (300 MHz,
CDCl3): l=1.26 (s, 18H, C(CH3)3), 2.26 (s, 6H,
PhꢀCH3), 2.55 (s, 3H, C(O)CH3), 2.58 (12H, PhꢀCH3),
5.17/5.35 (pt, 4H, CpꢀH), 6.92 (s, 4H, PhꢀH). — 13C-
NMR (75 MHz, CDCl3): l=21.6 (PhꢀCH3(para)), 23.7
(PhꢀCH3(ortho)), 25.3 (C(CH3)3), 29.6 (C(O)CH3), 62.9
(CpCꢀCH2CH3),
127.5
(PhꢀCpara),
128.9/131.1
(PhꢀCortho/meta), 134.6 (PhꢀCꢀS). — IR (KBr): w˜ =
2966, 2928, 1476, 1307 cm−1. — UV–vis (CH2Cl2):
umax (log m)=256 (4.47), 316 (4.36), 362 nm (3.70). —
HRMS (FAB+) [M+H+] C35H46CoO4S4: Calc.:
717.1611; Found: 717.1580%. C35H45CoO4S4 (717.2):
Calc.: C, 58.64; H, 6.33. Found: C, 58.42; H, 6.25%.
(C(CH3)3),
82.5
(C(CBD)ꢀSO2tBu),
86.9
(C(CBD)ꢀSMes), 87.9/88.6 (CpCꢀH), 96.6 (CpCꢀAc),
129.9 (PhCmeta), 131.0 (PhCꢀS), 140.1 (PhCpara), 144.1
(PhCortho), 197.1 (C(O)CH3). — IR (KBr): w˜ =

C. Benisch et al. / Journal of Organometallic Chemistry 641 (2002) 102–112
109
2926, 1685, 1461, 1309 cm−1. — UV–vis (CH2Cl2):
umax (log m)=258 (4.42), 318 (3.95), 378 nm (3.51). —
HRMS (FAB+) [M+H+] C37H48CoO5S4: Calc.:
759.1716; Found: 759.1755%. C37H47CoO5S4 (759.2):
Calc.: C, 58.55; H, 6.24; S, 16.90. Found: C, 58.67; H,
6.30; S, 15.80%.
(Si(CH3)3), 25.8 (SO2C(CH3)3), 32.9 (SC(CH3)3), 50.9
(SC(CH3)3), 62.8 (SO2C(CH3)3), 81.1
(C(CBD)ꢀSO2tBu), 88.9 (C(CBD)ꢀStBu), 93.7/94.6
(CpCꢀH), 95.1 (CpCꢀSiMe3). — IR (KBr): w˜ =
2961, 1314 cm−1. — UV–vis
(CH2Cl2):
umax
(log m)=264 (4.21), 320 nm (3.89). — HRMS (El+)
C28H49CoO4S4Si: Calc.: 664.1615; Found: 664.1617%.
5.2.16. (p5-Cyclopentadienyl)-[p4-1,2-bis(tert-
butylsulfonyl)-3,4-bis(tert-butylthio)cyclobutadiene]-
cobalt(I) (33)
5.2.19. (p5-Methoxycarbonylcyclopentadienyl)-
[p4-1,2-bis(tert-butylsulfonyl)-3,4-bis(tert-butylthio)-
cyclobutadiene]cobalt(I) (36)
Starting material: 230 mg (0.55 mmol) of Cp-
Co(CO)(BTSA) (8) and 222 mg (1.10 mmol) of bis(tert-
butylthio)acetylene (17). Yield: 99 mg (30%) of 33 as a
yellow solid, m.p. 204 °C (dec.). — 1H-NMR (300
MHz, CDCl3): l=1.48/1.50 (s, 36H, C(CH3)3), 5.38 (s,
5H, CpꢀH). — 13C-NMR (50 MHz, CDCl3): l=25.7
(SO2C(CH3)3), 32.8 (SC(CH3)3), 50.8 (SC(CH3)3), 62.5
(SO2C(CH3)3), 82.3 (C(CBD)ꢀSO2tBu), 84.0 (C(CBD)ꢀ
StBu), 87.8 (CpC). — IR (KBr): w˜ =2965, 1632,
Starting material: 238 mg (0.50 mmol) of
CpCo2MeCo(CO)(BTSA) (11) and 202 mg (1.00 mmol)
of bis(tert-butylthio)acetylene (17). Yield: 50 mg (15%)
of 36 as a yellow solid, m.p. 150 °C (dec.). — 1H-
NMR (500 MHz, CDCl3): l=1.50/1.52 (s, 36H,
C(CH3)3), 3.87 (s, 3H, CO2CH3), 5.65/5.81 (pt, 4H,
CpꢀH). — 13C-NMR (50 MHz, CDCl3): l=24.9
(SO2C(CH3)3), 32.2 (SC(CH3)3), 50.6 (SC(CH3)3), 52.0
(CO2CH3), 62.4 (SO2C(CH3)3), 82.0 (C(CBD)ꢀ
SO2tBu), 84.4 (C(CBD)ꢀStBu), 88.3/89.4 (CpCꢀH),
90.5 (CpCꢀCO2Me), 165.2 (CO2CH3). — IR (KBr):
1460, 1307 cm−1. — UV–vis
(CH2Cl2):
umax
(log m)=260 (4.44), 314 (4.07), 352 (3.57), 366 nm
(3.47). — HRMS (FAB+) [M+H+] C25H42CoO4S4:
Calc.: 593.1298; Found: 593.1332%. C25H41CoO4S4
(592.1): Calc.: C, 50.65; H, 6.97. Found: C, 50.61; H,
7.04%.
w˜ =2960, 1724, 1473 cm−1. — UV–vis
(CH2Cl2):
umax (log m)=248 (4.75), 310 nm (4.40). — HRMS
(FAB+): [M+H+] C27H44CoO6S4: Calc.: 651.1353;
Found: 651.1385%. C27H43CoO6S4 (651.1): Calc.: C,
49.83; H, 6.66; S, 19.71. Found: C, 49.62; H, 6.66; S,
19.68%.
5.2.17. (p5-Methylcyclopentadienyl)-[p4-1,2-bis(tert-
butylsulfonyl)-3,4-bis(tert-butylthio)cyclobutadiene]-
cobalt(I) (34)
Starting material: 239 mg (0.53 mmol) of CpMe-
Co(CO)(BTSA) (9) and 215 mg (1.06 mmol) of bis(tert-
butylthio)acetylene (17). Yield: 101 mg (31%) of 34 as a
orange solid, m.p. 138 °C (dec.). — 1H-NMR (500
MHz, CDCl3): l=1.48/1.50 (s, 36H, C(CH3)3), 2.07 (s,
3H, CpꢀCH3), 5.15/5.34 (pt, 4H, CpꢀH). — 13C-NMR
(125 MHz, CDCl3): l=12.7 (CpꢀCH3), 25.7
(SO2C(CH3)3), 32.9 (SC(CH3)3), 50.4 (SC(CH3)3), 62.6
(SO2C(CH3)3), 81.6 (C(CBD)ꢀSO2tBu), 82.6 (C(CBD)ꢀ
StBu), 86.4/88.9 (CpCꢀH), 101.4 (CpCꢀMe). — IR
(KBr): w˜ =2966, 2922, 1472, 1305 cm−1. — UV–vis
(CH2Cl2): umax (log m)=262 (4.31), 316 nm (3.98). —
HRMS (FAB+) [M+H+] C26H44CoO4S4: Calc.:
607.1454; Found: 607.1413%. C26H43CoO4S4 (606.1):
Calc.: C, 51.46; H, 7.14; S, 21.14. Found: C, 51.22; H,
7.14; S, 20.91%.
5.2.20. (p5-Acetylcyclopentadienyl)-
[p4-1,2-bis(tert-butylsulfonyl)-3,4-bis(tert-butylthio)-
cyclobutadiene]cobalt(I) (37)
Starting material: 230 mg (0.50 mmol) of AcCp-
Co(CO)(BTSA) (12) and 202 mg (1.00 mmol) of bis(-
tert-butylthio)acetylene (17). Yield: 54 mg (17%) of 37
as a yellow solid, m.p. 177 °C (dec.). — 1H-NMR
(500 MHz, CDCl3): l=1.48/1.50 (s, 36H, C(CH3)3),
2.49 (s, 3H, C(O)CH3), 5.71/5.86 (pt, 4H, CpꢀH). —
13C-NMR (50 MHz, CDCl3): l=25.7 (SO2C(CH3)3),
29.3 (C(O)CH3), 32.8 (SC(CH3)3), 51.5 (SC(CH3)3),
62.9 (SO2C(CH3)3), 83.0 (C(CBD)ꢀSO2tBu), 85.1
(C(CBD)ꢀStBu), 89.5/89.7 (CpCꢀH), 97.0 (CpCꢀAc),
196.7 (C(O)CH3). — IR (KBr): w˜ =2964, 1683,
1461, 1368 cm−1. — UV–vis
(CH2Cl2):
umax
(log m)=260 (4.56), 310 nm (4.20). — HRMS
(FAB+) [M+H+] C27H44CoO5S4: Calc.: 635.1404;
Found: 635.1431%. C27H43CoO5S4 (634.1): Calc.: C,
51.08; H, 6.83; S, 20.20. Found: C, 50.86; H, 6.83; S,
20.21%.
5.2.18. (p5-Trimethylsilylcyclopentadienyl)-[p4-
1,2-bis(tert-butylsulfonyl)-3,4-bis(tert-butylthio)-
cyclobutadiene]cobalt(I) (35)
Starting material: 245 mg (0.50 mmol) of
CpSiMe3Co(CO)(BTSA) (10) and 202 mg (1.00 mmol)
of bis(tert-butylthio)acetylene (17). Yield: 42 mg (13%)
of 35 as a orange solid, m.p. 84 °C (dec.). — 1H-
NMR (500 MHz, CDCl3): l=0.31 (s, 9H, Si(CH3)3),
1.48/1.49 (s, 36H, C(CH3)3), 5.30/5.76 (pt, 4H,
CpꢀH). — 13C-NMR (125 MHz, CDCl3): l=0.3
5.2.21. (p5-Cyclopentadienyl)-[p4-1,2-bis-
(tert-butylsulfonyl)-3,4-diphenylcyclobutadiene]cobalt(I)
(39)
Starting material: 209 mg (0.50 mmol) of Cp-
Co(CO)(BTSA) (8) and 89 mg (3.34 mmol) of tolane
(38). Yield: 209 mg (62%) of 39 as a orange solid. —

110
C. Benisch et al. / Journal of Organometallic Chemistry 641 (2002) 102–112
1H-NMR (500 MHz, CDCl3): l=1.33 (s, 18H,
1.75 (m, 12H, CH2), 4.94 (pt, 2H, CpꢀH), 5.12 (pt, 2H,
CpꢀH). — 13C-NMR (75 MHz, CDCl3): l= −0.2
(Si(CH3)3), 24.0 (C(CH3)3), 24.7/24.9/26.3 (CH2), 60.1
(C(CH3)3), 72.4 (C(CBD)ꢀCH2), 86.2 (C(CBD)ꢀ
SO2tBu), 88.1/89.1 (CpꢀC), 93.7 (CpCꢀSiMe3). — IR
(KBr): w˜ =2929, 2860, 1631, 1290 cm−1. — UV–vis
(CH2Cl2): umax (log m)=290 (4.15), 340 nm (3.14). —
HRMS (FAB+) C26H43CoO4S2Si: Calc.: 570.1704;
Found: 570.1721%.
C(CH3)3), 5.27 (s, 5H, CpꢀH), 7.26 (m, 6H, PhꢀH), 7.60
(m, 4H, PhꢀH). — 13C-NMR (125 MHz, CDCl3): l=
24.9 (C(CH3)3), 61.8 (C(CH3)3), 76.5 (C(CBD)ꢀPh),
82.5 (C(CBD)ꢀSO2tBu), 86.0 (CpꢀC), 128.2/130.6
(PhꢀCortho/meta), 128.3 (PhꢀCpara), 131.7 (PhCꢀ
CBD). — IR (KBr): w˜ =2971, 2931, 1631, 1443,
1307, 1117 cm−1. — UV–vis
(CH2Cl2):
umax
(log m)=240 (4.30), 264 (4.22), 302 (3.98), 350 (3.27),
396 nm (2.92). — HRMS (FAB+) C29H33CoO4S2:
Calc.: 568.1152; Found: 568.1169%.
6. X-ray crystallography and structure solutions
5.2.22. (p5-Methylcyclopentadienyl)-
[p4-1,2-bis(tert-butylsulfonyl)-3,4-diphenylcyclo-
butadiene]cobalt(I) (40)
Data were collected on a Syntex-R3-diffractometer
(24, 25 at 293 K), a Siemens-Stoe AED2 diffractometer
(36 at 295 K), a Nonius-CAD4 diffractometer (26 at
293 K) and a Bruker-Smart CCD-diffractometer (30
and 39–41 at 200 K) using graphite-monochromated
Starting material: 50 mg (0.12 mmol) of MeCp-
Co(CO)(BTSA) (9) and 21 mg (0.12 mmol) of tolane
(38). Yield: 44 mg (66%) of 40 as a orange solid. —
1H-NMR (300 MHz, CDCl3): l=1.31 (s, 18H,
C(CH3)3), 1.57(s, 3H, CpꢀCH3), 5.07 (pt, 2H, CpꢀH),
5.26 (pt, 2H, CpꢀH), 7.26 (m, 6H, PhꢀH), 7.60 (m, 4H,
PhꢀH). — 13C-NMR (75 MHz, CDCl3): l=11.4
(CpꢀCH3), 25.0 (C(CH3)3), 61.9 (C(CH3)3), 77.2
(C(CBD)ꢀPh), 81.7 (C(CBD)ꢀSO2tBu), 85.0/86.6
(CpꢀC), 99.7 (CpCꢀMe), 128.1 (PhꢀCpara), 128.2/130.4
(PhꢀCortho/meta), 131.8 (PhCꢀCBD). — IR (KBr): w˜ =
2973, 2930, 1475, 1443, 1308, 1116 cm−1. — UV–
vis (CH2Cl2): umax (log m)=248 (4.42), 274 (4.38), 310
,
Mo–Ka radiation (u=0.71073 A). Intensities of all
data-sets were corrected for Lorentz and polarization
effects. An empirical absorption correction was per-
formed for 24–26, 30 and 39–41. The structures were
solved by direct methods (SHELXS-97 [19]). The struc-
tural parameters of the non-hydrogen atoms were
refined anisotropically according to a full-matrix least-
squares technique (F2). The hydrogen atoms were con-
sidered at calculated positions using an appropriate
riding model. In some cases disorder of parts of the
structure was found: the tert-butyl groups of 26 are
disordered, each at two positions with 50% multiplicity,
one tert-butyl group of 40 (at S2) is disordered at two
positions with ca. 50% multiplicity, the SiMe3-group in
41 is disordered at two positions (63/37% occupation).
The refinement was carried out with SHELXL-97 [20]
(Table 5).
(4.15),
358
nm
(3.61). — HRMS
(FAB+)
C30H35CoO4S2: Calc.: 582.1309; Found: 582.1356%.
5.2.23. (p5-Trimethylsilylcyclopentadienyl)-
[p4-1,2-bis(tert-butylsulfonyl)-3,4-diphenylcyclo-
butadiene]cobalt(I) (41)
Starting material: 172 mg (0.35 mmol) of
Me3SiCpCo(CO)(BTSA) (10) and 62 mg (0.35 mmol) of
tolane (38). Yield: 80 mg (36%) of 41 as a orange
solid. — 1H-NMR (300 MHz, CDCl3): l= −0.22 (s,
9H, Si(CH3)3), 1.28 (s, 18H, C(CH3)3), 5.23 (pt, 2H,
CpꢀH), 5.91 (pt, 2H, CpꢀH), 7.29 (m, 6H, PhꢀH), 7.72
(m, 4H, PhꢀH). — 13C-NMR (75 MHz, CDCl3): l=
−0.7 (Si(CH3)3), 24.3 (C(CH3)3), 61.3 (C(CH3)3), 76.7
(C(CBD)ꢀPh), 81.8 (C(CBD)ꢀSO2tBu), 87.5/89.6
(CpꢀC), 92.4 (CpCꢀSiMe3), 127.4/130.3 (PhꢀCortho/meta),
127.7 (PhꢀCpara), 131.3 (PhCꢀCBD). — HRMS
(FAB+) C32H41CoO4S2Si: Calc.: 640.1548; Found:
640.1552%.
7. Supplementary material
Crystallographic data (excluding structure factors)
for the structures reported in this paper have been
deposited with the Cambridge Crystallographic Data
Centre as supplementary publication nos. CCDC —
162686 (24), — 162687 (25), — 162688 (26), —
162689
(30), — 162690
(36), — 162691
(39),
— 162692 (40), — 162693 (41). Copies of the data
can be obtained free of charge on application to The
Director, CCDC, 12 Union Road, Cambridge CB2
1EZ, UK (Fax: +44-1223-336033; e-mail: deposit@
ccdc.cam.ac.uk or www: http://www.ccdc.cam.ac.uk).
5.2.24. (p5-Trimethylsilylcyclopentadienyl)-
{1,8,9,10-p4-9,10-bis(tert-butylsulfonyl)-bicyclo-
[6.2.0]-deca-1,9-diene}cobalt(I) (42)
Starting material: 172 mg (0.35 mmol) of
Me3SiCpCo(CO)(BTSA) (10) and 38 mg (0.35 mmol) of
cyclooctyne (43). Yield: 151 mg (75%) of 42 as a
orange–red oil. — 1H-NMR (300 MHz, CDCl3): l=
0.24 (s, 9H, Si(CH3)3), 1.38 (s, 18H, C(CH3)3), 1.48–
Acknowledgements
We are grateful to the Deutsche Forschungsgemein-
schaft (SFB 247), the Fonds der Chemischen Industrie

C. Benisch et al. / Journal of Organometallic Chemistry 641 (2002) 102–112
111
Table 5
Crystallographic data of 24–26, 30, 36, 39–41
Compound
24
25
26
30
36
39
40
41
Empirical
formula
Molecular
mass
C29H33CoO4S4 C30H35CoO4S4 C32H41CoO4S4Si C35H45CoO4S4 C27H43CoO6S4 C29H33CoO4S2 C30H35CoO4S2 C32H41CoO4S2Si
632.8
646.8
293
705.0
293
716.935
200(2)
650.830
295(2)
568.60
200(2)
582.63
200(2)
640.79
200(2)
(g mol−1
)
Temperature 293
(K)
Crystal color Red
Crystal shape Polyhedron
Orange
Polyhedron
Orange
Needle
Yellow
Polyhedron
Monoclinic
Orange
Polyhedron
Monoclinic
Yellow
Polyhedron
Orthorhombic Orthorhombic Monoclinic
Orange
Polyhedron
Orange
Polyhedron
Crystal
system
Space group Pbca
Orthorhombic Orthorhombic Monoclinic
Pbca
17.704(5)
18.372(6)
18.604(5)
90
90
90
6051(3)
8
P21/n
11.744(4)
12.511(9)
24.58(2)
90
102.15(3)
90
3530(4)
4
P21/n
P21/c
Pbca
Pbca
P21/n
,
a (A)
17.865(5)
18.126(5)
18.297(5)
90
90
90
9.6829(2)
28.2080(5)
13.1599(3)
90
103.6930(10) 91.90(5)
90
18.455(2)
9.221(7)
18.49(1)
90
10.5333(1)
17.8048(2)
28.8910(3)
90
90
90
14.0195(1)
14.5048(2)
27.1778(4)
90
90
90
10.3384(2)
18.3567(3)
16.9720(3)
90
94.518(1)
90
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
90
3145(4)
4
3
,
V (A )
5925(3)
8
3492.27(12)
4
5418.3(1)
8
5526.6(1)
8
3210.9(1)
4
Z
Dcalc
1.42
1.42
1.33
1.36
1.37
1.39
1.40
1.33
(mg m−3
)
v (mm−1
F(000)
)
0.89
2640
0.88
2704
0.79
1480
0.767
1512
0.848
1376
0.821
2384
0.806
2448
0.736
1352
Crystal size 0.40×0.60
0.50×0.80
0.50×0.30×0.30 0.22×0.22
0.45×0.30
0.50×0.16
0.22×0.20
0.23×0.18×0.18
(mm)
×0.75
×0.95
0/23
0/23
0/24
6714
×0.12
×0.25
−21/20
0/10
0/21
4928
×0.11
−13/13
−23/23
−37/37
53 053
×0.18
−18/18
−18/18
−35/35
54 281
H
K
l
min/hmax
min/kmax
min/lmax
Reflections
collected
Reflections
unique
0/23
0/23
0/23
6588
0/15
0/16
−32/31
8892
−11/11
−34/32
−16/15
26 045
−13/12
−23/23
−21/22
21 165
5977
3937
6093
4085
8493
6212
6087
4590
4928
3000
6209
4745
6317
4418
7349
4853
Reflections
observed
Variables
R(F)
344
352
436
409
358
331
366
404
0.058
0.109
1.06
0.064
0.131
2.61
0.032
0.080
1.04
0.037
0.074
1.04
0.0534
0.1198
1.011
0.034
0.073
1.05
0.040
0.092
1.00
0.043
0.089
1.01
Rw(F2)
S
(Goodness-o
f-fit) and
F2
(Dz)max
0.57
0.46
0.25
0.30
0.404
0.34
0.46
0.35
(e A−3
)
(Dz)min
−0.28
−0.48
−0.34
−0.32
−0.35
−0.32
−0.37
−0.32
(e A−3
)
mon Press, New York, 1982, p. 248;
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financial support. T.H.S. thanks the Studienstiftung des
Deutschen Volkes for a scholarship.
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