Synthesis and characterization of diphenyl-2-thienylphosphine derivatives of di- and tricobalt carbonyl complexes1

Article abstract of DOI:10.1016/S0022-328X(98)00833-X

The reaction of [Co₂{μ-C₂(CO₂Me)₂}(CO) ₆] with the ligand diphenyl-2-thienylphosphine, PPh₂(C₄H₃S), yields the complexes [Co₂{μ-C₂(CO₂Me)₂}(CO) ₅{PPh₂(C₄H₃S)}] (1) and [Co₂{μ-C₂(CO₂Me)₂}(CO) ₄{PPh₂(C₄H₃S)}₂] (2). The related complex [Co₃(μ₃CMe)(CO)₉] reacts with the same ligand to give [Co₃(μ₃-CMe)(CO)₈{PPh₂(C ₄H₃S)}] (3) and [Co₃(μ₃-CMe)(CO)₇{PPh₂(C ₄H₃S))₂] (4). Thermolysis of 1 at 80°C leads to partial conversion of 1 into 2, which is isolated in low yield. Similarly, thermolysis of 3 at 70°C results in partial conversion of 3 to 4. Coordination of the thienyl unit of the diphenyl-2-thienylphosphine ligand to cobalt could not be detected in these thermolyses. Complexes 1-4 have been completely characterized and the crystal structure of complex 4 has been determined.

Full text of DOI:10.1016/S0022-328X(98)00833-X

Journal of Organometallic Chemistry 573 (1999) 272–278
Synthesis and characterization of diphenyl-2-thienylphosphine
derivatives of di- and tricobalt carbonyl complexes1
Jason D. King a, Magda Monari b, Ebbe Nordlander a,*
a Inorganic Chemistry 1, Chemical Center, Lund Uni6ersity, Box 124, S-221 00, Lund, Sweden
b Uni6ersita` di Bologna, Dipartimento di Chimica G. Ciamician, Via Selmi 2, I-40126 Bologna, Italy
Received 27 April 1998
Abstract
The reaction of [Co2{v-C2(CO2Me)2}(CO)6] with the ligand diphenyl-2-thienylphosphine, PPh2(C4H3S), yields the complexes
[Co2{v-C2(CO2Me)2}(CO)5{PPh2(C4H3S)}] (1) and [Co2{v-C2(CO2Me)2}(CO)4{PPh2(C4H3S)}2] (2). The related complex
[Co3(v3CMe)(CO)9] reacts with the same ligand to give [Co3(v3-CMe)(CO)8{PPh2(C4H3S)}] (3) and [Co3(v3-CMe)(CO)7
{PPh2(C4H3S))2] (4). Thermolysis of 1 at 80°C leads to partial conversion of 1 into 2, which is isolated in low yield. Similarly,
thermolysis of 3 at 70°C results in partial conversion of 3 to 4. Coordination of the thienyl unit of the diphenyl-2-thienylphosphine
ligand to cobalt could not be detected in these thermolyses. Complexes 1–4 have been completely characterized and the crystal
structure of complex 4 has been determined. © 1999 Elsevier Science S.A. All rights reserved.
Keywords: Cobalt; Carbonyl; Polyfunctional phosphine; Crystal structure
phorus and sulfur atoms in the complex [Re2(CO)8{v-
PPh2(C4H3S)}] [8]. Furthermore, reaction with
[Ru3(CO)12] results in C–H bond cleavage and bimetal-
lic products are isolated in which the thiophene moiety
of the ligand forms a |, p2-vinyl type bridge between
two metal atoms with phosphorus coordinating to the
third center [8]. Thermolysis of these complexes can
effect P–C bond scission, leaving the C4H2S residue
coordinated as a v4-thiophyne ligand [8].
We are interested in the preparation of new polynu-
clear molybdenum, ruthenium, osmium, cobalt,
rhodium, iridium and mixed-metal complexes contain-
ing thiophene ligands. Our aim is to establish possible
coordination modes of thiophene and its derivatives in
complexes containing several metal atoms, and to cor-
relate the structures and reactivities of such complexes
to intermediates and mechanisms of hydrodesulfuriza-
tion processes. Here we report the preparation of new
cobalt clusters into which thiophene has been intro-
duced via the agency of the diphenyl-2-thienylphos-
phine ligand. Thiophene-containing cobalt complexes
1. Introduction
There is sustained interest in the investigation of the
organometallic chemistry of thiophenes [1–3] with the
aim of elucidating the mechanisms of commercial cata-
lytic hydrodesulfurization reactions [1–4]. Thiophenes
themselves are relatively poor ligands for transition
metals and, in an attempt to circumvent this limitation,
the ligand diphenyl-2-thienylphosphine [5] has been em-
ployed as a means of introducing the thiophene group
into a transition metal complex. Some complexes have
been synthesized in which this ligand acts as a simple
tertiary phosphine [6,7], donating via the phosphorus
atom only, but it has recently been demonstrated that
diphenyl-2-thienylphosphine can also act as a bidentate
ligand, coordinating to rhenium through both the phos-
* Corresponding author. Fax: +46 46 2224439; e-mail:
ebbe.nordlander@inorg.lu.se
1 Dedicated to Brian F.G. Johnson on the occasion of his 60th
birthday, in recognition of his outstanding contributions to organ-
metallic and inorganic chemistry.
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII S0022-328X(98)00833-X

J.D. King et al. / Journal of Organometallic Chemistry 573 (1999) 272–278
273
are of particular interest since cobalt is currently em-
ployed as a promoter [4,9] in the molybdenum-cata-
lyzed hydrodesulfurization of petroleum feedstocks.
on the NMR timescale. Mechanisms involving localized
site exchange [11] or metal fragment reorientation [12]
have been discussed previously for such complexes and
the findings here are consistent with either proposal. As
may be expected, only one resonance was detected for
the CO ligands in the 13C-NMR spectrum of 2.
2. Results and discussion
2.2. Reaction of [Co3(v3-CMe)(CO)9] with
PPh2(C4H3S)
2.1. Reaction of [Co2{v-C2(CO2Me)2}(CO)6] with
PPh2(C4H3S)
Mild heating of [Co3(v3-CMe)(CO)9] in the presence
of an excess of PPh2(C4H3S) gave [Co3(v3-CMe)(CO)8-
{PPh2(C4H3S)}] (3) and [Co3(v3-CMe)(CO)7{PPh2(C4-
H3S)}2] (4) in a 23 and 32% yield, respectively. The
FAB mass spectrometric and microanalytical data are
consistent with the suggested formulae and the IR
spectra of 3 and 4 are typical of alkylidyne tricobalt
carbonyl complexes with one and two phosphine (or
phosphite) ligands, respectively [13]. The carbon atoms
of the CO groups in 3 give rise to a single, broad peak
in the 13C-NMR spectrum at l 204.1, which remains
even when the spectrum is recorded at 183 K. A
low-energy fluxional process clearly operates to render
all the carbonyl ligands equivalent. Such a process
requires exchange of carbonyls between axial and equa-
torial positions and between cobalt atoms.
The static structure of 4 (Fig. 1b) indicates that all
carbonyl ligands are inequivalent but only two signals
are observed in the 13C-NMR spectrum of this com-
plex. The two resonances appear at l 210.2 and l 204.0
with intensities in the approximate ratio 4:3. This result
is consistent with a fluxional process featuring localized
exchange of axial and equatorial carbonyls but not
delocalized exchange of carbonyls between cobalt
atoms. On the basis of the integration of the signals, the
upfield resonance is assigned to the carbonyl ligands at
the unsubstituted cobalt atom and the resonance that
occurs at lower field is thus attributed to the carbonyls
of the substituted cobalt centres.
The thermal reaction of [Co2{v-C2(CO2Me)2}(CO)6]
with an excess of PPh2(C4H3S) in toluene led to the
formation of [Co2{v-C2(Co2Me)2}(CO)5{PPh2(C4H3
S)}] (1) and [Co2{v-C2(CO2Me)2}(CO)4{PPh2(C4H3
S)}2] (2) in a 24 and 40% yield, respectively. Both
complexes have been characterized by IR, 1H-, 13C- and
31P-NMR spectroscopy, mass spectrometry and micro-
analysis. The FAB mass spectra and microanalytical
data are in agreement with the proposed formulae, as
are the IR data which are in accord with those collected
for other mono- and bis-substituted alkyne dicobalt
carbonyl complexes [10]. In the 13C-NMR spectrum of
1, resonances at l 203.9 and l 199.3 with intensities in
the approximate ratio 2:3 are assigned to the carbon
atoms of the CO groups on the substituted and unsub-
stituted cobalt atoms, respectively. (Fig. 1a) indicates
that the Co(CO)3 group of 1 should give rise to sepa-
rate resonances for axial and equatorial carbonyl lig-
ands if the static structure is maintained in solution.
The 13C-NMR data suggest, however, that in solution
at 293 K a fluxional process occurs which renders all
the carbonyl ligands at a given metal center equivalent
2.3. The molecular structure of [Co3(v3-CMe)(CO)7
{PPh2(C4H3S)}2] (4)
It was possible to grow crystals of 4 suitable for
X-ray diffraction experiments and the crystal structure
was determined in order to confirm the proposed struc-
ture. The molecular structure of [Co3(v3-CMe)-
(CO)7{PPh2(C4H3S)}2] (4) is shown in Fig. 2; it corre-
sponds to the expected static structure depicted in (Fig.
1b). Relevant bond lengths and angles are reported in
Table 1 and fractional coordinates for all non-hydrogen
atoms are listed in Table 2. The cluster core consists of
an almost equilateral Co3 triangle capped by the
v3-ethylidyne moiety. The two diphenyl-2-thienyl-
phosphine ligands are coordinated in equatorial
positions on Co(1) and Co(2), trans to metal–metal
Fig. 1. (a) Proposed static molecular structures of [Co2{v-
C2(CO2Me)2}(CO)5{PPh2(C4H3S)}] (1) and [Co2{v-C2(CO2Me)2}
(CO)4{PPh2(C4H3S)}2] (2). In 1, a fluxional process involving lo-
calised site exchange [11] or non-dissociative reorientation about
Co(1) [12] will render carbonyls a and b equivalent. (b) Proposed
static molecular structures of [Co3(v3-CMe)(CO)8{PPh2(C4H3S)}] (3)
and [Co3(v3-CMe)(CO)7{PPh2(C4H3S)}2] (4). In 3, carbonyls a and b
may be rendered equivalent by dissociative localised site exchange or
non-dissociative reorientation about Co(1). In 4, the same carbonyls
can be rendered equivalent by dissociative localised site exchange but
not by non-dissociative reorientation about Co(1).

274
J.D. King et al. / Journal of Organometallic Chemistry 573 (1999) 272–278
Table 2
Fractional
atomic
coordinates
(×104)
for
[Co3(v3-
CMe)(CO)7{PPh2(C4H3S)}2] · 0.5C6H14 · H2O (4)
x
y
z
Co (1)
Co (2)
Co (3)
P (1)
P (2)
C (8)
C (9)
C (1)
O (1)
C (2)
O (2)
C (3)
O (3)
C (4)
O (4)
C (5)
O (5)
C (6)
1607 (1)
2629 (1)
2530 (1)
578 (1)
7420 (1)
6935 (1)
6924 (1)
7857 (1)
7103 (1)
6425 (4)
5612 (4)
7052 (4)
6802 (3)
8383 (4)
9002 (3)
6060 (4)
5484 (3)
7727 (4)
8218 (3)
6529 (4)
6240 (3)
6387 (5)
6030 (4)
7903 (4)
8512 (3)
8833 (2)
8448 (4)
8655 (4)
9109 (5)
9259 (5)
7140 (2)
7339 (3)
6798 (4)
6057 (3)
5858 (2)
6400 (2)
8513 (2)
9284 (2)
9778 (2)
9501 (3)
8730 (3)
8236 (2)
8104 (2)
8328 (3)
9104 (3)
9655 (2)
9431 (3)
8655 (3)
6936 (6)
6884 (7)
6850 (8)
−441 (1)
−254 (1)
3007 (2)
112 (2)
2079 (2)
4550 (2)
1881 (6)
1754 (7)
3844 (7)
4579 (5)
3123 (6)
3415 (5)
2054 (6)
1726 (5)
2350 (6)
2189 (5)
−376 (6)
−989 (5)
−336 (7)
−918 (6)
359 (6)
685 (6)
1058 (7)
2761 (7)
3507 (5)
1214 (6)
985 (5)
−1402 (7)
−2009 (5)
−1438 (6)
−2054 (5)
518 (7)
Fig. 2. A SCHAKAL [16] drawing of the molecular structure of
[Co3(v3-CMe)(CO)7{PPh2(C4H3S)}2] (4) in the solid state, showing
the atom numbering scheme. The hydrogens of the phenyl and thienyl
rings have been omitted for clarity.
975 (5)
−1766 (8)
−2714 (6)
−598 (7)
−801 (6)
5624 (3)
4356 (6)
4500 (7)
5620 (9)
6404 (9)
3822 (4)
4484 (5)
5168 (5)
5190 (5)
4528 (5)
3844 (5)
2415 (4)
2334 (5)
1776 (5)
1299 (5)
1380 (5)
1938 (5)
787 (4)
O (6)
C (7)
O (7)
S (1)
bonds, as has previously been found in the related
complex [Co3(v3-CMe)(CO)7{P(OPh)3}2] [14]. The
cobalt atoms complete their pseudo-octahedral coordi-
nation spheres with three [Co(3)] or two terminal car-
bonyl ligands. The Co–Co bond lengths fall in a
narrow range (Co(1)–Co(2)=2.484, Co(1)–Co(3)=
248 (6)
3317 (3)
3405 (6)
4632 (6)
5456 (8)
4918 (12)
1393 (4)
763 (5)
C (10)
C (11)
C (12)
C (13)
C (14)
C (15)
C (16)
C (17)
C (18)
C (19)
C (20)
C (21)
C (22)
C (23)
C (24)
C (25)
C (36)
C (37)
C (38)
C (39)
C (40)
C (41)
C (26)
C (27)
C (28)
C (29)
S (2)
C (30)
C (31)
C (32)
C (33)
C (34)
C (35)
C (411)
C (421)
C (431)
C (441)
C (451)
C (461)
˚
2.488 and Co(2)–Co(3)=2.480(1) A, Co–Coave=2.484
˚
345 (5)
557 (5)
A) and are comparable to those found in [Co3(v3-
˚
CMe)(CO)7{P(OPh)3}2] (Co–Coave=2.488 A) [14] and
1186 (5)
1604 (4)
1030 (3)
1534 (3)
755 (4)
Table 1
˚
Selected bond lengths (A) and angles (°) for [Co3(v3-
CMe)(CO)7{PPh2(C4H3S)}2] · 0.5C6H14 · H2O (4)
−529 (4)
˚
−1033 (3)
−254 (4)
5477 (4)
6004 (5)
6581 (5)
6631 (5)
6104 (5)
5527 (4)
4855 (9)
4025 (12)
4720 (13)
5915 (19)
6303 (6)
5304 (8)
4626 (6)
5218 (7)
6487 (7)
7165 (6)
6573 (8)
5096 (11)
4191 (8)
4516 (10)
5745 (11)
6650 (8)
6326 (10)
Bond length (A)
Co(1)–Co(2)
Co(1)–Co(3)
Co(2)–Co(3)
Co(l)–P(1)
Co(2)–P(2)
P(1)–C(14)
C(10)–S(1)
S(1)–C(13)
C(10)–C(11)
P(2)–C(36)
C(26)–S(2)
C(29)–C(28)
C(26)–C(27)
C(1)–O(1)
C(2)–O(2)
C(3)–O(3)
C(4)–O(4)
C(5)–O(5)
C(6)–O(6)
C(7)–O(7)
2.484(2)
2.488(2)
2.480(1)
2.207(2)
2.217(2)
1.846(4)
1.682(7)
1.75(1)
1.397(9)
1.850(4)
1.69(1)
1.34(2)
1.49(2)
1.125(8)
1.142(7)
1.135(8)
1.122(8)
1.127(8)
1.126(9)
1.128(8)
Co(1)–C(8)
Co(2)–C(8)
Co(3)–C(8)
C(8)–C(9)
1.891(7)
1.927(6)
1.910(7)
1.495(9)
1.835(4)
1.816(7)
1.38(1)
2088 (4)
2546 (5)
1704 (7)
403 (6)
P(1)–C(20)
P(l)–C(10)
C(12)–C(13)
C(12)–C(11)
P(2)–C(30)
P(2)–C(26)
S(2)–C(29)
C(27)–C(28)
Co(l)–C(1)
Co(l)–C(2)
Co(2)–C(3)
Co(2)–C(4)
Co(3)–C(5)
Co(3)–C(6)
Co(3)–C(7)
−56 (4)
−1238 (9)
−2628 (13)
−3326 (14)
−2636 (19)
−1018 (6)
1138 (9)
1110 (9)
1876 (9)
2670 (9)
2698 (9)
1932 (10)
−1179 (10)
−2430 (11)
−3434 (8)
−3185 (9)
−1934 (11)
−930 (8)
1.38(1)
1.833(7)
1.800(9)
1.73(2)
6838 (11)
6906 (4)
6404 (5)
5657 (5)
5130 (4)
5350 (5)
6097 (5)
6624 (4)
7111 (8)
7032 (7)
6987 (8)
7022 (8)
7102 (7)
7146 (8)
1.41(2)
1.778(8)
1.804(7)
1.750(7)
1.808(7)
1.780(7)
1.770(8)
1.830(8)
Bond angle (°)
Co(3)–Co(l)–P(1) 101.90(8)
P(l)–Co(l)–C(1) 94.5(2)
Co(l)–Co(2)–P(2)
P(2)–Co(2)–C(3)
99.43(6)
96.1(2)

J.D. King et al. / Journal of Organometallic Chemistry 573 (1999) 272–278
275
Table 2 (Continued)
2.4. Thermolysis of [Co2{v-C2(CO2Me)2}(CO)5{PPh2-
(C4H3S)}] (1) and [Co3(v3-CMe)(CO)8{PPh2(C4H3S)}]
(3)
x
y
z
C (452)
C (462)
C (472)
C (482)
S (3)
C (42)
C (43)
C (44)
O (8)
1203 (9)
5385 (7)
4914 (7)
5808 (10)
6886 (9)
6905 (6)
71 (21)
558 (19)
1577 (24)
3727 (8)
6471 (5)
5680 (5)
5319 (4)
5813 (4)
6741 (4)
386 (11)
1114 (13)
1790 (15)
4899 (8)
Thermolyses of 1 and 3 were undertaken in attempts
to coordinate the thienyl moieties of the diphenyl-2-
thienylphosphine ligands. Thermolysis of [Co2{v-
C2(CO2Me)2}(CO)5{PPh2(C4H3S)}] (1) at 80°C leads to
partial conversion of the starting material to the corre-
sponding bis-substituted complex, [Co2{v-C2(CO2-
Me)2}(CO)4{PPh2(C4H3S)}2] (2), which is isolated in a
9% yield. A similar conversion is observed when
[Co3(v3-CMe)(CO)8{PPh2(C4H3S)}] (3) is heated at
70°C; 70% of the starting complex is recovered along
with a 13% yield of the bis-substituted derivative
[Co3(v3-CMe)(CO)7{PPh2(C4H3S)}2] (4). Higher tem-
peratures result in substantial decomposition of the
complexes in both reactions. Products containing a
bridging bidentate PPh2(C4H3S) ligand were not ob-
tained. Compounds 1 and 3 have a fairly low thermal
stability and under prolonged thermolysis, gradual de-
composition of the sample is likely, releasing phosphine
into the reaction mixture. Recombination of liberated
phosphine with the starting complex (1 or 3) may then
generate the bis-substituted complex. This process is
expected to be facile under the conditions employed.
1150 (10)
2021 (12)
2717 (10)
2359 (6)
4899 (22)
4338 (19)
4251 (26)
4360 (11)
the parent cluster [Co3(v3-CMe)(CO)9] (Co–Coave
=
˚
2.468(5) A) [15]. The triply bridging ethylidyne car-
bon is virtually equidistant from the three cobalt
atoms (Co(1)–C(8)=1.891(7), Co(2)–C(8)=1.927(6),
Co(3)–C(8)=1.910(7), Co–C(8)ave 1.909 A), which is
analogous to what is found in the aforementioned
˚
[Co3(v3-CMe)(CO)7{P(OPh)3}2] (Co–C(Me)ave 1.907
˚
A). The methyl hydrogen atoms are staggered with
respect to the Co3 plane. The Co–P interactions
(Co(1)–P(1)=2.207(2), Co(2)–P(2)=2.217(2) A) are
normal and slightly longer than those reported for
[Co3(v3-CMe)(CO)7{P(OPh)3}2] (2.137 and 2.141(2) A)
˚
˚
[14].
2.5. Reaction of 1 and 3 with BuLi and PPh2Cl
The arrangement of the phosphine substituents in
the diphenyl-2-thienylphosphine ligands deserves some
attention in view of the potential of the S atoms
belonging to the thienyl rings to coordinate to metal
centres. Both the thienyl rings are almost coplanar
with the Co3 plane; the dihedral angles between the
Co(1)–Co(2)–Co(3) and the C4H3S rings are 12.2(3)
and 20.2(3)° for the rings containing S(1) and S(2),
respectively. The sulfur atoms S(1) and S(2) are di-
rected away from the Co atoms. Using the program
SCHAKAL [16], various conformations of the
diphenyl-2-thienylphosphine ligand were modelled.
In order to investigate the reactivity of the thienyl
moiety of the coordinated ligand, [Co2{v-C2(CO2Me)2}-
(CO)5{PPh2(C4H3S)}] (1) and [Co3(v3-CMe)(CO)8{PPh2-
n
(C4H3S)}] (3) were each reacted with BuLi followed by
addition of PPh2Cl in an attempt to lithiate the thienyl
group and add PPh2 to create a diphosphine. In both
cases, this reaction causes substantial conversion of the
starting material to the corresponding bis-substituted
complex. It is likely that, even at low temperatures, the
butyl anion attacks a carbonyl ligand of the cluster(s).
Initially, this leads to decomposition of the cluster,
liberating PPh2(C4H3S). Subsequently, facile BuLi as-
sisted CO substitution can occur on the starting mate-
rial by the freed phosphine, leading to the bis-
substituted complex. Products containing a (PPh2)2
(C4H2S) ligand were not observed.
Even after
a rotation of 180° around the P–
C(thienyl) axes, the distances of the sulfur atoms
from the closest Co atoms are 3.54 [Co(2)–S(2)] and
˚
3.65 A [Co(1)–S(1)]. Furthermore, there is orienta-
tional disorder between one phenyl group and the
thienyl ring attached to P(2). The modelling indicated
that rotation of the PPh2(C4H3S) cone by 180°
around the Co–P axis and subsequent rotation of the
thienyl group by 180° around the P–C(thienyl) axis
will bring the S atom within bonding distance of the
vicinal cobalt atom. The diphenyl-2-thienyl phosphine
might act as a bidentate ligand through the two het-
eroatoms but the preferred orientation of the thienyl
sulfur inside the phosphine cone prevents its coordi-
nation to a metal centre, as has also been found in
[Ru3(v-H){v-PPh2(C4H2S)}(CO)8{PPh2(C7H3S)}] [8].
3. Summary and conclusion
Mono- and bis-substituted diphenyl-2-thienylphos-
phine derivatives of [Co2{v-C2(CO2Me)2}(CO)6] and
[Co3(v3-CMe)(CO)9] may be prepared in reasonable
yields and under mild conditions. However, attempts at
coordination of the thienyl moieties of the PPh2(C4H3S)
ligands by thermal or chemical activation of the lig-
ands/clusters do not yield any tractable products, ex-

276
J.D. King et al. / Journal of Organometallic Chemistry 573 (1999) 272–278
cept in the case of thermolysis of the mono-substituted
complexes [Co2{v-C2(CO2Me)2}(CO)5{PPh2(C4H3S)}]
(1) or [Co3(v3-CMe)(CO)8{PPh2(C4H3S)}] (3) which re-
sults in some diproportionation to yield the correspond-
ing bis-substituted complexes 3 and 4 in low yield. The
above-mentioned modelling based on the solid state
structure of 4 indicates that the PPh2(C4H3S) ligands
may not be predisposed to coordinate in a bridging
mode. Furthermore, the relatively low thermal stability
of the cobalt complexes used here appears to prevent
thermal activation of the diphenyl-2-thienylphosphine.
We are presently investigating the reactions of
diphenyl-2-thienylphosphine and related ligands with
second and third row transition metal complexes/clus-
ters. The resultant complexes are expected to have
greater thermal stability than the above-mentioned
cobalt species, and thermal activation of the
thienylphosphine ligands may thus be feasible.
top of a silica chromatography column. Elution with
hexane/acetone (7:3) gave [Co2{v-C2(CO2Me)2}-
(CO)5{PPh2(C4H3S)}] (1) (213 mg, 24%) and [Co2{v-
C2(CO2Me)2}(CO)4{PPh2(C4H3S)}2] (2) (480 mg, 40%).
Complex 1: Anal. Found: C, 48.9%; H, 2.9%; P, 4.8%;
S, 4.9%. Co2C27H19O9PS Calc.: C, 48.5%; H, 2.9%; P,
4.6%; S, 4.8%. MS (m/z): 668 (M+) and M+ −nCO
(n=1–5). IR (CH2Cl2, cm−l): w(CO) 2083 s, 2036 vs,
2024 sh, 1991 w. NMR (CDCl3), 1H, l 7.7–7.1 (m,
13H, Ph and C4H3S), l 3.38 (s, 6H, Me); 13C{1H}, l
203.9 (s, 2CO), l 199.3 (s, 3CO) l 169.4 (s, CO2Me), l
137.4–128.2 (Ph, C4H3S), l 72.2 (s, C–CO2Me), l 52.2
(s, CO2Me); 31P{1H}, l 40.0 (s). Complex 2: Anal.
Found: C, 55.6%; H, 3.6%; P, 7.0%; S, 7.0%.
Co2C42H32O8P2S2 Calc.: C, 55.5%; H, 3.6%; P, 6.8%; S,
7.1%. MS (m/z): 880 (M+ –CO) and M+
−nCO (n=2–4). IR (CH2Cl2, cm−1): w(CO) 2042s,
2003 m, 1984 m. NMR (CDCl3), 1H, l 7.6–7.1 (m,
26H, Ph and C4H3S), l 2.80 (s, 6H, Me); 13C{1H}, l
205.0 (s, CO), l 169.4 (s, CO2Me), l 137.3–128.0 (Ph,
C4H3S), l 68.1 (s, C–CO2Me), l 51.1 (s, CO2Me);
31P(1H}, l 39.0 (s).
4. Experimental
All reactions were carried out under an atmosphere
of dry, oxygen free nitrogen, using solvents which were
freshly distilled from appropriate drying agents. IR
spectra were recorded in n-hexane or dichloromethane
solution in 0.5 mm NaCl cells, using a Bio-Rad FTS
6000 spectrometer. Fast atom bombardment (FAB+)
mass spectra were obtained on a JEOL SX-102 instru-
ment; 3-nitrobenzyl alcohol was used as a matrix and
CsI as the calibrant. NMR spectra were recorded on a
Varian Unity 300 MHz spectrometer using the solvent
resonance as an internal standard for the 1H- and
13C-NMR spectra, while H3PO4 was used as an external
standard for the 31P spectra. Microanalyses were per-
formed by Mikrokemi AB, Uppsala, Sweden. Column
chromatography was performed on Merck Kieselgel 60
(70–230 mesh ASTM); products are given in order of
decreasing Rf values. The starting materials Co2(CO)8
(Strem Chemical), C2(CO2Me)2 (Acros Organics),
CH3CCl3 (Aldrich), PPh2Cl (Acros) and C4H4S (Syn-
thetic Chemicals) were used without further purifica-
tion. The compounds PPh2(C4H3S), [Co2{v-C2(CO2
Me)2}(CO)6], and [Co3(v3-CMe)(CO)9] were prepared
by literature methods [8,17,18].
4.2. Reaction of [Co3(v3-CMe)(CO)9] with
PPh2(C4H3S)
The cluster [Co3(v3-CMe)(CO)9] (470 mg, 1.03 mmol)
and PPh2(C4H3S) (414 mg, 1.54 mmol) were dissolved
in toluene (60 cm3) and heated at 35°C with stirring for
24 h. After removal of the reaction solvent under
vacuum, the residue was dissolved in the minimum
quantity of dichloromethane and adsorbed onto silica.
The silica was pumped dry and transferred to the top of
a silica chromatography column. Elution with hexane/
dichloromethane (4:1) gave [Co3(v3-CMe)(CO)8{PPh2-
(C4H3S)}] (3) (165 mg, 23%) and [Co3(v3-CMe)(CO)7-
{PPh2(C4H3S)}2] (4) (309 mg, 32%). Crystals of 4 were
grown by evaporation of a hexane/dichloromethane
solution of the complex at −18°C. Complex 3: Found:
C, 45.0%; H, 2.4%; P, 4.5%; S, 4.6%. Co3C26H16O8PS
Calc.: C, 44.9%; H, 2.3%; P, 4.5%; S, 4.6%. MS (m/z):
640(M+ –2CO) and M+ –nCO (n=3–8). IR (n-hex-
ane, cm−1): w(CO) 2078 m, 2052 w, 2034 s, 2022 s, 2014
s, 1994 w, 1989 w, 1970 w. NMR (CD2Cl2), 1H, l
7.7–7.2 (m, 13H, Ph and C4H3S), l 3.28 (s, 3H, Me);
13C{1H}, l 275.6 (s, C–Me), l 204.1 (s, CO), l 137.7–
128.4 (Ph, C4H3S), l 44.4 (s, Me); 31P{1H}, l 39.1 (s).
Complex 4: Anal. Found: C, 52.3%; H, 3.3%; P, 6.6%;
S, 6.8%. Co3C41H29O7P2S2 Calc.: C, 52.6%; H, 3.1%; P,
4.1. Reaction of [Co2{v-C2(CO2Me)2}(CO)6] with
PPh2(C4H3S)
A sample of [Co2{v-C2(CO2Me)2}(CO)6] (570 mg,
1.33 mmol) and PPh2(C4H3S) (535 mg, 2.00 mmol) were
dissolved in toluene (60 cm3) and heated at 35°C with
stirring for 29 h. After removal of the reaction solvent
under vacuum, the residue was dissolved in the mini-
mum quantity of dichloromethane and adsorbed onto
silica. The silica was pumped dry and transferred to the
6.6%; S, 6.9%. MS (m/z): 852 (M+ –3CO) and M+
–
nCO (n=4–7). IR (n-hexane, cm−1): w(CO) 2052 s,
1
2005 vs, 1997 vs, 1985 s, 1960 w. NMR (CD2Cl2), H,
l 7.7–7.1 (m, 26H, Ph and C4H3S), l 2.92 (s, 3H, Me).
NMR (CDCl3), 13C{1H}, l 277.1 (s, C–Me), l 210.2 (s,
4CO), l 204.0 (s, 3CO), l 137.1–128.1 (Ph, C4H3S), l
42.6 (s, Me); 31P{1H}, l 38.1 (s).

J.D. King et al. / Journal of Organometallic Chemistry 573 (1999) 272–278
277
4.3. Thermolysis of [Co2{v-C2(CO2Me)2}(CO)5{PPh2-
(C4H3S)}] (1)
PPh2Cl (86 ml, 106 mg, 0.48 mmol) was added. The
mixture was allowed to warm to r.t. and was stirred at
r.t. for 30 min. Thin layer chromatography of a with-
drawn aliquot indicated the presence of [Co3(v3-
CMe)(CO)8{PPh2(C4H3S)}] (3), [Co3(v3-CMe)(CO)7-
{PPh2(C4H3S)}2] (4) and immobile decomposition prod-
ucts only.
A
total
of
250
mg
of
[Co2{v-C2(CO2
Me)2}(CO)5{PPh2(C4H3S)}] (0.38 mmol) was dissolved
in toluene (60 cm3) and heated at 80°C with stirring for
20 h. After removal of the solvent under vacuum, the
residue was dissolved in the minimum quantity of
dichloromethane and adsorbed onto silica. The silica
was pumped dry and transferred to the top of a silica
chromatography column. Elution with hexane/acetone
(7:3) gave [Co2{v-C2(CO2Me)2}(CO)5{PPh2(C4H3S)}]
(1) (204 mg, 82%) and [Co2{v-C2(CO2Me)2}-
(CO)4{PPh2(C4H3S)}2] (2) (32 mg, 9%).
4.7. X-ray structure determination of [Co3(v3-CMe)-
(CO)7{PPh2(C4H3S)}2] · 0.5C6H14 · H2O
Crystal data and details of the data collection for
4 · 0.5C6H14 · H2O are given in Table 3. The diffrac-
tion experiments were carried out at 193 K on a fully
automated Enraf-Nonius CAD-4 diffractometer using
graphite-monochromated Mo–Kh radiation. The unit
cell parameters were determined by a least-squares
fitting procedure using 25 reflections. Data were cor-
rected for Lorentz and polarization effects. No decay
correction was necessary. An empirical absorption cor-
rection was applied using the azimuthal scan method
[19]. The positions of the metal atoms were found by
direct methods using the SHELXS 86 program [20] and
all the non-hydrogen atoms located from Fourier-dif-
ference maps. The methyl H atoms were located in the
4.4. Thermolysis of [Co3(v3-CMe)(CO)8{PPh2-
(C4H3S)}] (3)
A total of 233 mg of [Co3(v3-CMe)(CO)8{PPh2-
(C4H3S)}] (0.33 mmol) was dissolved in toluene (60
cm3) and heated at 70°C with stirring for 20 h. After
removal of the reaction solvent under vacuum, the
residue was dissolved in the minimum quantity of
dichloromethane and adsorbed onto silica. The silica
was pumped dry and transferred to the top of a silica
chromatography column. Elution with hexane/
dichloromethane (4:1) gave [Co3(v3-CMe)(CO)8{PPh2-
(C4H3S)}] (3) (163 mg, 70%) and [Co3(v3CMe)(CO)7-
{PPh2(C4H3S)}2] (4) (40 mg, 13%).
Table 3
Crystal
data
and
experimental
details
for
[Co3(v3-
CMe)(CO)7{PPh2(C4H3S)}2] · 0.5C6H14 · H2O (4)
Empirical formula
C41H29Co3O7P2S2 · 0.5C6H
4.5. Reaction of [Co2{v-C2(CO2Me)2}(CO)5{PPh2-
(C4H3S)}] (1) with BuLi and PPh2Cl
· H2O
988.52
193(2)
0.71073
Triclinic
14
M
Temperature (K)
Wavelength (A)
Crystal symmetry
Space group
Unit cell dimensions
˚
The mono-substituted dicobalt complex [Co2{v-
C2(CO2Me)2}(CO)5{PPh2(C4H3S)}] (1) (655 mg, 0.98
mmol) was dissolved in THF and cooled to −78°C.
Butyl lithium (613 ml 1.6 M in hexane, 0.98 mmol) was
added via a syringe. The reaction mixture was allowed
to warm to room temperature (r.t.). After cooling once
more to −78°C, PPh2Cl (176 ml, 216 mg, 0.98 mmol)
was added. The mixture was allowed to warm to r.t.
and was stirred at r.t. for 30 min. Thin layer chro-
matography of a withdrawn aliquot indicated the pres-
ence of [Co2{v-C2(CO2Me)2}(CO)5{PPh2(C4H3S)}] (1),
[Co2{v-C2(CO2Me)2}(CO)4{PPh2(C4H3S)}2] (2) and im-
mobile decomposition products only.
P1( (no. 2)
˚
a (A)
00.634(9)
12.209(4)
17.718(8)
102.75(3)
89.69(4)
115.04(3)
2213(2)
˚
b (A)
˚
c (A)
h (°)
i (°)
k (°)
3
˚
V (A )
Z
2
Dcalc. (mg m−3
)
1.484
1.328
1000
0.175×0.20×0.27
v(Mo–Ka) (mm−1
F(000)
)
Crystal size (mm)
q limits (°)
2–30
Scan mode
ꢀ
4.6. Reaction of [Co3(v3-CMe)(CO)8{PPh2(C4H3S)}]
(3) with BuLi and PPh2Cl
Reflections collected
Unique observed reflections
(Fo\4|(Fo)]
11138 (9h, 9k, +l)
4201
The mono-substituted tricobalt methylidyne complex
[Co3(v3-CMe)(CO)8{PPh2(C4H3S)}] (3) (332 mg, 0.48
mmol) was dissolved in THF and cooled to −78°C.
BuLi (300 ml 1.6 M in hexane, 0.48 mmol) was added
via a syringe. The reaction mixture was allowed to
warm to r.t. After cooling once more to −78°C,
Goodness of fit on F2
R1 (F)a, wR2 (F2)b
Weighting scheme
0.936
0.0601, 0.1648
a=0.1072, b=0.0000b
1.053 and −0.894
−3
˚
Largest diff. peak and hole (e A
)
a R1=ꢀꢁFoꢂ–ꢂFcꢂ/ꢀꢂFoꢂ. b wR2=[ꢀw(F2o–Fc2)2/ꢀw(Fo2)2]0.5 where w=
1/[|2(F2o)+(aP)2+bP] where P=(Fo2+2F2c)/3.

278
J.D. King et al. / Journal of Organometallic Chemistry 573 (1999) 272–278
Fourier maps but were placed in calculated positions.
One hexane molecule sitting around an inversion centre
and one water molecule in a general position were also
found in the asymmetric unit. The phenyl rings of the
phosphine ligands were refined as rigid hexagons (C–C
Nordlander from the Swedish Natural Science Research
Council (NFR) and the European Union (TMR Net-
work Metal Clusters in Catalysis and Organic Synthesis-
MECATSYN) and by grants to M. Monari from the
Ministero della Ricerca Scientifica e Tecnologica, the
Consiglio Nazionale delle Ricerche (CNR) and the
University of Bologna (project ‘Molecole e Aggregati
Molecolari Intelligenti’). A postdoctoral fellowship to
J.D. King was funded by the MECATSYN network. We
are indebted to Dr Fabio Prestopino for assistance in the
preparation of Fig. 2.
˚
1.39, C–H 0.93 A, C–C–C 120°) and the hydrogen
atoms were added in calculated positions. During refin-
ement, some atoms of one phenyl ring [C(30)–C(35)] and
the thienyl group bonded to P(2) exhibited unrealistic
thermal ellipsoids and bond distances. As there was
confidence in the quality of the data set, some orienta-
tional disorder in the phosphine cone was proposed and
a model was constructed incorporating two orientations
of the phosphine ligand related by a 120° rotation around
the Co–P axis. This model yielded superimposed images
of the thienyl and phenyl rings involved; the remaining
phenyl group [C(36)–C(41)] was not affected. The suc-
cessful refinement of the disordered model showed a
slightly unbalanced distribution of the phenyl and thienyl
groups; the most populated conformation (0.56) is shown
in Fig. 2. The final refinement on F2 proceeded by full
matrix least-squares calculations (SHELXL93) [21] using
anisotropic thermal parameters for all non-hydrogen
atoms with the exception of the disordered thienyl and
phenyl rings and hexane molecule. The methylene and
the phenyl H atoms were assigned an isotropic thermal
parameter 1.2 times Ueq of the carbon atoms to which
they were attached.
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5. Supplementary material
A complete list of bond lengths and angles as well as
tables of hydrogen coordinates and anisotropic displace-
ment parameters for all atoms have been deposited with
the Cambridge Crystallographic Data Centre, 12 Union
Road, Cambridge CB2 1EZ, UK. Structure factors are
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Acknowledgements
[21] G.M. Sheldrick, SHELXL 93, Program for crystal structure
refinement, University of Go¨ttingen, 1993.
This research has been supported by grants to E.
.