Metal-induced B-H activation. Addition of phenylacetylene to Cp*Rh-, Cp*Ir-, (p-cymene)Ru- and (p-cymene)Os halfsandwich complexes containing a chelating 1,2-dicarba-closo-dodecaborane-1,2-dichalcogenolate ligand

Article abstract of DOI:10.1016/S0022-328X(00)00221-7

The addition reactions of the 16e halfsandwich complexes Cp*M[S₂C₂(B₁₀H₁₀)] (IS M = Rh, 2S M = Ir) and η⁶-(4-isopropyltoluene)M[S₂C₂(B ₁₀H₁₀)] (3S M = Ru and 4S M = Os) with phenylacetylene lead selectively to the 18e complexes 5S-8S, in which a metal-boron bond is present and the phenylacetylene is regio- and stereoselectively inserted into one of the M-S bonds, with one hydrogen atom transferred from the carborane cage to the terminal carbon of the alkyne, corresponding to ortho-metalation of the carborane cage. In all cases, the S-η²-(Ph)CC and the C(1)B units are linked to the metal in cisoid positions. The analogous reaction of Cp*Ir[Se₂C₂(B₁₀H₁₀)] 2Se with phenylacetylene gives 6Se. Complex 5S undergoes an intramolecular rearrangement in solution to the isomer 9S, where the Rh-B bond is cleaved, the B-atom now bearing the organic substituent, and a metal-carbon σ bond being formed together with a coordinative S → Rh bond. In contrast, the p-cymene complexes 7S and 8S rearrange into isomers 10S and 11S, in which the S-η²-(Ph)C-C and the C(1)-B(M) moieties occupy transoid positions, preventing further intramolecular rearrangements. The proposed structures in solution were deduced from NMR data (¹H-, ¹¹B-, ¹³C-, ⁷⁷Se-, and ¹⁰³Rh-NMR) and X-ray structural analyses were carried out for 5S, 6Se, 9S and 10S.

Full text of DOI:10.1016/S0022-328X(00)00221-7

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 604 (2000) 170–177
Metal-induced BꢀH activation. Addition of phenylacetylene to
Cp*Rh-, Cp*Ir-, (p-cymene)Ru- and (p-cymene)Os halfsandwich
complexes containing a chelating
1,2-dicarba-closo-dodecaborane-1,2-dichalcogenolate ligand
Max Herberhold * 1, Hong Yan, Wolfgang Milius, Bernd Wrackmeyer * 2
Laboratorium fu¨r Anorganische Chemie, Uni6ersita¨t Bayreuth, Postfach 10 12 51, D-95440 Bayreuth, Germany
Received 10 December 1999; accepted 31 March 2000
Dedicated to Professor Herbert W. Roesky on the occasion of his 65th birthday.
Abstract
The addition reactions of the 16e halfsandwich complexes Cp*M[S2C2(B10H10)] (1S M=Rh, 2S M=Ir) and h6-(4-isopropyl-
toluene)M[S2C2(B10H10)] (3S M=Ru and 4S M=Os) with phenylacetylene lead selectively to the 18e complexes 5S–8S, in which
a metalꢀboron bond is present and the phenylacetylene is regio- and stereoselectively inserted into one of the MꢀS bonds, with
one hydrogen atom transferred from the carborane cage to the terminal carbon of the alkyne, corresponding to ortho-metalation
of the carborane cage. In all cases, the S-h2-(Ph)CC and the C(1)B units are linked to the metal in cisoid positions. The analogous
reaction of Cp*Ir[Se2C2(B10H10)] 2Se with phenylacetylene gives 6Se. Complex 5S undergoes an intramolecular rearrangement in
solution to the isomer 9S, where the RhꢀB bond is cleaved, the B-atom now bearing the organic substituent, and a metalꢀcarbon
s bond being formed together with a coordinative S“Rh bond. In contrast, the p-cymene complexes 7S and 8S rearrange into
isomers 10S and 11S, in which the S-h2-(Ph)CꢀC and the C(1)ꢀB(M) moieties occupy transoid positions, preventing further
intramolecular rearrangements. The proposed structures in solution were deduced from NMR data (1H-, 11B-, 13C-, 77Se-, and
103Rh-NMR) and X-ray structural analyses were carried out for 5S, 6Se, 9S and 10S. © 2000 Elsevier Science S.A. All rights
reserved.
Keywords: Carboranes; Iridium; Osmium; Rhodium; Ruthenium, Selenium; Sulfur; X-ray; NMR
1. Introduction
(2Se) [3] which contain both the pentamethylcyclopen-
tadienyl (Cp*) and the ortho-carborane diselenolato
ligand [Se2C2(B10H10)]2−. In the present contribution
we compare the sulphur analogues 1S and 2S with the
corresponding p-cymene-ruthenium- and -osmium com-
plexes (3S and 4S [4]) in their reactivity towards pheny-
lacetylene. We have already started to study the
reactivity of 1S towards acetylene carboxylic acid
methyl esters and have found a remarkable activity not
only for the RhꢀS bonds but also for the carborane
cage [5]. From the preliminary studies [5] it had become
clear that in all these 16e complexes the metal itself, the
metalꢀchalcogen bonds and also the carborane cage at
the site of B(3) or B(6), being close to the metal, have
to be considered as potentially reactive centres.
The conversion of 16e complexes into their 18e con-
geners by oxidative addition at the metal is a well-
known systematic route to new products [1]. However,
if additional reactive centres are available in the 16e
complexes, the preferred mode of addition becomes less
predictable. We have recently reported on the 16e half-
sandwich complexes of rhodium (1Se) [2] and iridium
1 *Corresponding author. Tel.: +49-921-552540; fax: +49-921-
552157; e-mail: max.herberhold@uni-bayreuth.de
2 *Corresponding author. Tel.: +49-921-552542; fax: +49-921-
552157.
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(00)00221-7

M. Herberhold et al. / Journal of Organometallic Chemistry 604 (2000) 170–177
171
2. Results and discussion
1S with terminal acetylenes [6]. If it is assumed that the
coordinative E“M bond can be opened, the 18e com-
plex B is in equilibrium with a 16e complex B%. The
structure of B% is less rigid than that of B, thus the
metal atom becomes able to approach the B(3,6) sites
of the carborane cage and to induce BꢀH activation [7].
By this route the MꢀB and MꢀH bonds in C are formed
and the final step is the transfer of hydrogen from the
metal to the carbon atom to give 5–8. In all complexes
5–8 the E-h2-(Ph)CꢀC and the C(1)ꢀB(M) bonds point
into the same direction with respect to the metal centre
(cisoid arrangement). A typical 13C-NMR spectrum is
shown for 7S in Fig. 1. The presence of the MꢀB bond
in 5–8 suggests that these complexes will be ready for
further transformations.
2.1. Synthesis of the 16e complexes 1–4
The starting complexes 1–4 were prepared following
the published procedures [3,4] as shown in Scheme 1.
2.2. Reaction of the 16e complexes 1–4 with
phenylacetylene
All complexes 1–4 react with phenylacetylene in 1:1
stoichiometry to give the 18e complexes 5–8 (Scheme
2). The intermediates A, B and C were not detected
when the reactions were monitored by NMR. However,
complexes analogous to B have been isolated from the
reaction of 1S with dimethyl acetylene dicarboxylate
[5], and also from the reaction of the CpCo analogue of
2.3. Rearrangement reactions of the complexes 5–8
The iridium complexes 6S and 6Se appeared to be
stable under the conditions which induced rearrange-
ments in the other complexes 5S, 7S and 8S.
2.3.1. Rearrangement of 5S to its isomer 9S
In boiling chloroform the Cp*Rh complex 5S rear-
ranges slowly as shown in Scheme 3. All NMR data
(Table 1; see Fig. 2 for the 13C-NMR spectrum) were in
support of the structure 9S in which the RhꢀB bond
has been cleaved, while new BꢀC and RhꢀC s bonds
have been formed, together with a coordinative S“Rh
interaction. The latter is proposed to be present in
solution, since l103Rh= +32991 is more typical [3,8]
of an 18e complex. This structure was then confirmed
for the solid state by an X-ray structural analysis of 9S
(see below).
Scheme 1.
2.3.2. Rearrangement of 7S and 8S to their isomers
10S and 11S
Heating of 7S or 8S in CDCl3 or carrying out the
reaction of 3S or 4S with phenylacetylene in boiling
chloroform affords products which contain the same
structural units as 7S or 8S but possess apparently a
different structure (Scheme 4). The NMR data (Table
1) suggest striking structural differences between these
isomers and this was confirmed by the X-ray structural
analysis of 10S (Fig. 6) which shows that the S-h2-
(Ph)CꢀC and the C(1)ꢀB(M) bonds now point into
opposite directions (transoid arrangement) in the coor-
dination sphere of the ruthenium atom. The analogous
NMR data sets of 10S and 11S suggest that the os-
mium derivative 11S possesses the same structural fea-
tures as 10S. In contrast to the situation for 5S (Fig. 3)
and 9S (Fig. 5), the transoid structure of 10S and 11S
prevents further intramolecular rearrangements involv-
ing the MꢀB bond.
Scheme 2.

172
M. Herberhold et al. / Journal of Organometallic Chemistry 604 (2000) 170–177
Fig. 1. 62.9 MHz 13C{1H}-NMR spectrum of 7S in CD2Cl2, measured at 22°C. All 18 13C resonances are visible. The 13C(1,2) carborane signals,
marked (a) and (b), are somewhat broader and less intense than the other signals.
2.4. NMR spectroscopic results
selected bond lengths and bond angles. The cisoid ar-
rangement of the E-h2-(Ph)CꢀC and the C(1)ꢀB(M)
units in 5S (Fig. 3) is also present in 6Se (Fig. 4), in
contrast to the situation in 10S (Fig. 6). There are two
independent molecules of 5S in the unit cell and this
was also found in the case of the rearranged product 9S
(Fig. 5). Most bond lengths and bond angles are in the
usual ranges. However, the bond length C(1)ꢀC(2)=
178.4(5) pm in 10S is exceptionally long (as compared
with the typical range of o-carborane derivatives of
162–170 pm [10]) whereas some of the bond lengths
BꢀC are shorter than expected (cf. the typical range of
170–175 pm [10]). This indicates a considerable distor-
tion of the carborane cage in 10S, in agreement with
changes of the l13C(1,2) values when compared with
those of 7S (see Table 1). The five-membered rings
containing the metal centre are non-planar, as expected
for 18e compounds (in contrast to the 16e starting
complexes [2]). All four-membered metallacycles
MS(2)CB are planar within experimental error.
The 13C-NMR data (Table 1) and all other NMR
data (see Section 4) of the complexes 5–11 are in
agreement with the proposed structures and confirm
that the relevant features of the solid state structures of
5S, 6Se, 9S and 10S are retained in solution. The Figs.
1 and 2 show typical 13C-NMR spectra. Straightfor-
ward assignments were made by using both 2D H/1H
1
COSY experiments and 2D 13C/1H HETCOR spectra,
1
based on coupling constants J(13C,1H) and long range
coupling constants nJ(13C,1H) (n=2, 3). The small
values (B3 Hz) of the geminal coupling constants
2
ꢀ J(1H,1H)ꢀ in 5–8, 10 and 11 are typical of terminal
alkenes coordinated to metal centres. In contrast, in 9S
2
the magnitude of ꢀ J(1H,1H)ꢀ for the BCH2 group is
1
large (14.7 Hz) and characteristic of diastereotopic H
nuclei in geminal positions of an alkyl group. The 103Rh
chemical shifts were determined by selective heteronu-
clear 1H{103Rh} double resonance experiments which
also served to distinguish between coupling constants
J(1H,1H) and J(103Rh,1H). 11B-NMR spectra of 5–11
showed the pattern of overlapping signals (see Section
4) expected for unsymmetrically substituted ortho-car-
borane derivatives [9]; the 11B-NMR signal of the
boron atom linked to the respective metal centre (5–8,
10 and 11) or to the CH2 group in 9S is readily assigned
in each case by comparison of 1H coupled and 1H
decoupled 11B-NMR spectra.
2.5. X-ray structural analyses of the complexes 5S,
6Se, 9S and 10S
The molecular structures of the complexes 5S, 6Se,
9S and 10S are shown in the Figs. 3–6 together with
Scheme 3.

M. Herberhold et al. / Journal of Organometallic Chemistry 604 (2000) 170–177
173
Table 1
13C-NMR data a of the complexes 5–11
(E2C2B10H10
)
Cp* or p-cymene
EꢀCꢀ(Ph)
94.9 (9.1)
73.9
CH2
Ph
5S
6S
95.5, 103.0 (3.6)
97.5, 101.9
78.8, 91.6
9.1, 105.5 (3.5)
46.2 (9.7)
28.6
128.1, 129.3, 129.4,
139.8
128.2, 128.7, 129.4,
141.0
128.4, 128.6, 129.9,
142.2
8.5, 101.6
6Se
7S
8.9, 101.5
66.3
30.8
94.7, 103.9
96.1, 103.0
92.7, 96.5
18.5, 22.5, 23.1, 31.3, 96.4, 99.2, 101.1, 104.8, 110.0, 121.6
17.5, 21.8, 23.6, 30.2, 88.8, 91.2, 93.1, 95.9, 107.4, 116.0
9.1, 99.4 (6.2)
85.4
35.2
125.4, 128.0, 128.9,
144.5
125.7, 127.2, 128.5,
145.3
124.2, 125.5, 128.9,
150.6
8S
69.4
22.6
9S
94.7 (21.8)
35.1 (br)
10S
11S
110.8, 111.0
109.1, 109.6
17.0, 21.1, 24.9, 31.4, 97.4, 98.8, 100.8, 105.0, 105.8, 118.4
17.1, 21.1, 24.8, 31.1, 90.5, 90.8, 94.9, 98.7, 100.6, 112.2
81.3
67.0
50.5
37.1
126.9, 128.3, 145.2
126.7, 127.4, 128.3,
147.1
a All complexes were measured in CD2Cl2 (except 8S in CDCl3) at 22°C; J(103Rh,13C) (90.5 Hz) in parentheses; (br) denotes the signal of a
13C nucleus linked to boron by a 2c/2e bond.
Fig. 2. 62.9 MHz 13C{1H}-NMR spectrum of 9S in CD2Cl2 at 22°C. The broad signal of a CH2 group at high field, marked (d), indicates the
presence of a carbon atom linked to boron by a 2c/2e bond. The signal marked (c) is a doublet with 1J(103Rh,13C)=21.8 Hz, typical of a 2c/2e
RhꢀC bond.
3. Conclusions
[11]) and [(p-cymene)MCl2]2 (M=Ru [12], Os [13])
were prepared according to established procedures; n-
butyllithium (1.6 M in hexane), ortho-carborane, 1,2-
C2B10H12, and phenylacetylene were used as com-
mercial products. The 16e complexes Cp*M[E2C2-
The 16e complexes 1–4 proved to be versatile
reagents in their reactions with phenylacetylene and this
is promising for future studies using other alkynes and
comparable unsaturated substrates. The activation of
BꢀH bonds and the formation of MꢀB bonds (ortho-
metalation), followed by selective substitution of the
carborane cage in the case of 9(S), is an interesting
aspect in carborane chemistry.
4. Experimental
4.1. General and starting materials
The starting complexes [Cp*MCl2]2 (M=Rh [11], Ir
Scheme 4.

174
M. Herberhold et al. / Journal of Organometallic Chemistry 604 (2000) 170–177
Fig. 3. Molecular geometry of 5S. Selected bond lengths (pm) and
angles (°): Rh(1)ꢀB(6) 209.8(8), Rh(1)ꢀC(3) 214.8(7), Rh(1)ꢀC(4)
218.1(7), Rh(1)ꢀS(2) 240.94(16), Rh(1)ꢀring centre 190.9, C(1)ꢀS(1)
176.7(7), C(4)ꢀS(1) 181.5(7), C(2)ꢀS(2) 178.0(7), C(1)ꢀC(2) 171.0(10),
C(3)ꢀC(4) 139.5(11); C(3)Rh(1)C(4) 37.6(3), C(3)Rh(1)S(2) 87.6(2),
B(6)Rh(1)S(2) 72.4(2), B(6)Rh(1)C(3) 84.5(3), C(1)S(1)C(4) 102.5(3),
C(2)C(1)S(1) 116.1(5), C(1)C(2)S(2) 112.1(4), C(2)S(2)Rh(1) 87.6(2);
C(4)Rh(1)B(6)/C(4)S(1)C(1)B(6) 157.8; plane Rh(1)B(6)C(2)S(2), av-
erage deviation 1.5 pm.
Fig. 5. Molecular geometry of 9S. Selected bond lengths (pm) and
angles (°): Rh(1)ꢀC(4) 212.8(3), Rh(1)ꢀS(1) 231.16(10), Rh(1)S(2)
235.38(10), Rh(1)ꢀring centre 185.8, C(1)ꢀS(1) 178.2(3), C(2)ꢀS(2)
176.6(3), C(4)ꢀS(1) 182.4(4), C(1)ꢀC(2) 168.8(5), C(3)ꢀC(4) 153.5(4),
B(3)ꢀC(3) 157.2(5); C(4)Rh(1)S(1) 48.3(1), C(4)Rh(1)S(2) 91.22(9),
S(1)Rh(1)S(1) 91.85(3), C(1)S(1)C(4) 97.20(16), C(2)C(1)S(1) 116.2(2);
C(1)C(2)S(2) 119.6(2), C(1)S(1)Rh(1) 107.15(12), C(2)S(2)Rh(1)
104.81(12),
B(3)C(3)C(4)
111.4(3),
C(3)C(4)Rh(1)S(2)/
C(3)B(3)C(2)S(2) 122.3; plane Rh(1)S(1)C(1)C(2)S(2), average devia-
tion 2.9 pm.
Fig. 4. Molecular geometry of 6Se. Selected bond lengths (pm) and
angles (°): IrꢀB(6) 210.4(10), IrꢀC(3) 214.7(9), IrꢀC(4) 212.1(9),
IrꢀSe(2) 251.34(9), Irꢀring centre 192.4, C(1)ꢀSe(1) 190.4(10),
C(3)ꢀSe(1) 197.8(9), C(2)ꢀSe(2) 193.4(9), C(1)ꢀC(2) 170.1(13),
C(3)ꢀC(4) 142.4(13); C(3)IrC(4) 39.0(4), C(3)IrSe(2) 87.8(3),
B(6)IrC(3) 89.7(4), B(6)IrC(4) 85.5(4), C(1)Se(1)C(3) 99.1(4),
C(2)C(1)Se(1) 117.9(6), C(1)C(2)Se(2) 111.7(6), C(2)Se(2)Ir 85.8,
C(3)IrB(6)/C(3)Se(1)C(1)B(6) 155.0; plane IrB(6)C(2)Se(2), average
deviation 1.6 pm.
(B10H10)] (M=Rh [3], Ir [2]; the syntheses for E=S is
described below [14]) and (p-cymene)M[S2C2(B10H10)]
(M=Ru, Os [4]) were obtained as described. NMR
measurements: Bruker ARX 250 and DRX 500 spec-
trometers (see also Table 1); chemical shifts are given
with respect to CHCl3/CDCl3 (l1H=7.24; l13C=77.0)
or CDHCl2 (l1H=5.33, l13C=53.8), external Et2O–
BF3 (l11B=0 for J(11B)=32.083971 MHz), external
Me2Se (l77Se=0 for J(77Se)=19.071523 MHz) and
Fig. 6. Molecular geometry of 10S. Selected bond lengths (pm) and
angles (°): RuꢀB(3) 214.3(4), RuꢀC(3) 218.5(4), RuꢀC(4) 213.4(4),
RuꢀS(2) 241.28(10), Ruꢀring centre 179.8, C(1)S(1) 175.8(4), C(2)S(2)
176.2(4), C(3)S(1) 182.1(4), C(1)ꢀC(2) 178.4(5), C(3)ꢀC(4) 141.7(5);
C(3)RuB(3) 84.34(17), C(4)RuC(3) 38.29(14), C(4)RuS(2) 81.26(11),
B(3)RuS(2) 70.19(12), C(1)S(1)C(3) 102.52(18), C(2)C(1)S(1) 115.6(2),
C(1)C(2)S(2)
112.5(2),
C(2)S(2)Ru
90.30(12),
C(3)RuB(3)/
C(3)S(1)C(1)B(3) 149.1; plane RuS(2)C(2)B(3), average deviation 1.2
pm.

M. Herberhold et al. / Journal of Organometallic Chemistry 604 (2000) 170–177
175
l103Rh=0 for J(103Rh)=3.16 MHz. Mass spectra:
Finnigan MAT 8500 for EI-MS (70 eV), direct inlet;
Varian MAT 311A for FD-MS. IR spectra: Perkin–
Elmer 985.
125.4 mg) and phenylacetylene (0.2 ml, 2 mmol) in
CHCl3 (30 ml) was stirred for 10 days at r.t. or 2 days
at 62°C. The colours of the reaction mixtures changed
gradually from blue–purple (2S) to light yellow for 6S
or from green (2Se) to yellow for 6Se. The solvent was
removed in vacuo and the respective residue was
washed with hexane. Recrystallisation from CH2Cl2
solutions at −18°C gave light-yellow crystals of 6S or
yellow crystals of 6Se.
4.2. Dilithio 1,2-dicarba-closo-dodecaborane-1,2-
dithiolate and -diselenolate
A solution of 1,2-C2B10H12 (0.29 g; 2 mmol) in Et2O
(40 ml) was treated with 2.75 ml of a solution of
n-butyllithium (1.6 M in hexane; 4.4 mmol) at room
temperature (r.t.). Addition of sulphur (0.14 g; 4 mmol)
or selenium (0.35 g; 4 mmol) and stirring of the reac-
tion mixture for 1–3 h at r.t. gave a yellow solution of
Li2E2C2(B10H10) in quantitative yield.
1
6S: Yield, 101.8 mg, 80%, m.p.=205°C (dec.). H-
NMR (CD2Cl2): l=1.55 (s, 15H, Cp*), 2.67 (d,
J
HꢀH=2.5 Hz, 1H, PhCꢀCH2), 3.22 (d, JHꢀH=2.5 Hz,
1H, PhCꢀCH2), 7.20 (m, 3H, Ph) and 7.69 (m, 2H, Ph).
11B-NMR (CD2Cl2): l= −5.4, −6.5, −10.6, −12.4,
−13.4, −14.5, −25.0 (IrꢀB) (5:1:1:1:1:1). IR (KBr):
2560, 2588(wBꢀH). EI-MS (70 ev): 636 [M+, 30%], 534
[M+−(PhCꢁCH), 100%].
4.3. Pentamethylcyclopentadienyl-(1,2-dicarba-
closo-dodecaborane-1,2-dithiolato)-iridium,
Cp*Ir[S2C2(B10H10)] (2S)
1
6Se: Yield, 122.6 mg, 84%, m.p.=192°C (dec.). H-
NMR (CD2Cl2): l=1.60 (s, 15H, Cp*), 2.70 (d,
J
HꢀH=2.8 Hz, 1H, PhCꢀCH2), 3.21 (d, JHꢀH=2.8 Hz,
A solution of dilithium 1,2-dicarba-closo-dodecabo-
rane-1,2-dithiolate (1 mmol) in Et2O (60 ml) was added
to a solution of [Cp*IrCl2]2 (0.5 mmol) in THF (60 ml).
The colour of the Et2O/THF solution changed immedi-
ately from yellow to purple. The solvents were evapo-
rated under reduced pressure and the residue
chromatographed on silica (Merck, Kieselgel 60). Elu-
tion with CH2Cl2/hexane (5/1) gave a purple zone
which contained 0.49 g (92%) of 2S. IR (CsI):
1H, PhCꢀCH2), 7.19 (m, 3H, Ph) and 7.68 (m, 2H, Ph).
11B-NMR (CD2Cl2): l= −4.2, −5.2, −6.7, −10.0,
−10.9, −12.3, −13.9, −23.2 (IrꢀB) (2:2:1:1:1:1:1:1).
77Se-NMR (CD2Cl2): l=315.4 (IrꢀSe), 630.0
(C(Ph)ꢀSe). IR (KBr): 2562, 2584(wBꢀH). FD-MS: 730
[M+, 100%].
4.6. Preparation of 7S and 8S
w(BꢀH)=2566, 2590 cm−1 1H-NMR (CDCl3): l=
.
The solution of either (p-cymene)Ru[S2C2(B10H10)]
3S (88.4 mg, 0.2 mmol) or (p-cymene)Os[S2C2(B10H10)]
4S (106 mg, 0.2 mmol) and phenylacetylene (0.2 ml, 2
mmol) in CH2Cl2 (30 ml) was stirred at r.t. for 1 day
(7S) or 3 days (8S). The colour changed from blue (3S)
or from purple (4S) to brown–red. Evaporation of the
solvent and removal of the excess of phenylacetylene by
washing with hexane gave 7S as a deep-yellow powder;
8S was isolated by chromatography on silica gel
(Merck, Kieselgel 60) with a 1:1 mixture of hexane–
CH2Cl2 (v/v) for elution. Recrystallisation of 8S from
CH2Cl2 at −18°C afforded yellow crystals.
1.87 (s, Cp*). 13C-NMR (CDCl3): l=10.1, 91.8 (Cp*),
92.8 (S2C2). 11B-NMR: l= −6.3, −7.8, −8.7, −
10.1. EI-MS (70 eV): m/z (%)=534 (100) [M+].
4.4. Preparation of 5S
A mixture of Cp*Rh[S2C2(B10H10)] 1S (0.3 mmol;
133.5 mg) and phenylacetylene (3 mmol; 0.3 ml) in
CH2Cl2 (30 ml) was stirred at r.t. for 3 days; the colour
gradually turned red. The solvent was then removed
under reduced pressure, the residue was washed with
hexane and finally recrystallised from a CH2Cl2 solu-
tion at −18°C. Yield, 140 mg, 85%, red crystals,
m.p.=145°C (dec.). 1H-NMR (CD2Cl2): l=1.49 (s,
15H, Cp*), 3.11 (dd, JHꢀH=JRhꢀH=2.3 Hz, 1H,
1
7S: yield, 87 mg, 80%; m.p.=124°C (dec.). H-NMR
(CD2Cl2): l=0.95 (d, J=6.9 Hz, 3H, CH(CH3)2), 1.09
(d, J=6.9 Hz, 3H, CH(CH3)2), 2.05 (s, 3H, CH3), 2.46
(sp, J=6.9 Hz, 1H, CH(CH3)2), 2.55 (d, J=2.9 Hz,
1H, PhCꢀCH2), 3.96 (d, J=2.9 Hz, 1H, PhCꢀCH2),
5.38 (d, J=6.0 Hz, 1H, C6H4), 5.40 (d, J=6.0 Hz, 1H,
C6H4), 5.48 (d, J=6.0 Hz, 1H, C6H4), 5.58 (d, J=6.0
Hz, 1H, C6H4), 7.22 (m, 3H, Ph) and 7.90 (m, 2H, Ph).
11B-NMR (CD2Cl2): l= −4.5, −5.2, −6.7, −11.0
(RuꢀB), −13.5 (2:2:1:3:2). IR (KBr): wBꢀH=2581
PhCꢀCH2), 3.18 (dd,
JHꢀH=JRhꢀH=2.3 Hz, 1H,
PhCꢀCH2), 7.24 (m, 3H, Ph) and 7.80 (m, 2H, Ph).
11B-NMR (CD2Cl2): l= −4.2, −5.0, −6.6, −9.8,
−12.3, −13.4, −14.8 (RhꢀB) (1:3:1:1:1:2:1). 103Rh-
NMR (CD2Cl2): l= −17491. IR (KBr): 2567,
2583(wBꢀH). EI-MS (70 eV): 547 [M+, 86%], 445 [M+−
(PhCꢁCH), 74%].
cm−1
.
FD-MS: 544 [M+, 100%], 442 [M+−
4.5. Preparation of 6S and 6Se
(PhCꢁCH), 90%].
1
8S: yield, 95 mg, 75%; m.p.=155°C (dec.). H-NMR
(CDCl3): l=1.02 (d, J=6.9 Hz, 3H, CH(CH3)2), 1.03
(d, J=6.9 Hz, 3H, CH(CH3)2), 2.03 (s, 3H, CH3), 2.27
A solution of Cp*Ir[S2C2(B10H10)] 2S (0.2 mmol;
106.8 mg) or Cp*Ir[Se2C2(B10H10)] 2Se (0.2 mmol;

176
M. Herberhold et al. / Journal of Organometallic Chemistry 604 (2000) 170–177
(sp, J=6.9 Hz, 1H, CH(CH3)2), 2.37 (d, J=3.5 Hz,
1H, PhCꢀCH2), 4.25 (d, J=3.5 Hz, 1H, PhCꢀCH2),
5.29 (d, J=6.3 Hz, 2H, C6H4), 5.37 (d, J=6.3 Hz, 2H,
C6H4), 7.20 (m, 3H, Ph) and 7.80 (m, 2H, Ph). 11B-
NMR (CDCl3): l= −5.3, −10.9, −13.0, −14.3, −
CH(CH3)2), 1.21 (d, J=6.8 Hz, 3H, CH(CH3)2), 1.62
(s, 3H, CH3), 2.42 (sept, J=6.8 Hz, 1H, CH(CH3)2),
3.60 (d, J=1.65 Hz, 1H, PhCꢀCH2), 4.44 (dd, J1=1.2,
J2=6.3 Hz, 1H, C6H4), 4.98 (d, J=1.65 Hz, 1H,
PhCꢀCH2), 5.51 (dd, J1=1.5, J2=6.3 Hz, 1H, C6H4),
6.37 (dd, J1=1.5, J2=6.3 Hz, 1H, C6H4), 6.45 (dd,
J1=1.2, J2=6.3 Hz, 1H, C6H4), 7.14 (m, 1H, Ph), 7.24
(m, 2H, Ph) and 7.59 (m, 2H, Ph). 11B-NMR (CD2Cl2):
l= −2.8, −4.9, −6.2, −8.7 (RuꢀB), −9.6, −11.6
(1:1:3:2:1:2). IR (KBr): 2547, 2568, 2584, 2603(wBꢀH).
EI-MS (70 ev): 544 [M+, 20%], 442 [M+−(PhCꢁCH),
100%].
19.0 (OsꢀB) (5:2:1:1:1). IR (KBr): wBꢀH=2580 cm−1
.
EI-MS (70 eV): 633 [M+, 8%], 531 [M+−(PhCꢁCH),
100%].
4.7. Preparation of 9S
Phenylacetylene (4 mmol; 0.4 ml) was added to the
green solution of Cp*Rh[S2C2(B10H10)] 1S (0.4 mmol;
178 mg) in CHCl3 (40 ml) and the mixture was heated
under reflux for 2 days. The colour changed to red
within the first two hours and then gradually to
brown–red. Evaporation of the solvent in vacuo and
chromatography on silica gel (Merck, Kieselgel 60) with
2:1 hexane–CH2Cl2 as eluent gave a red zone of 5S
(yield, 76.6 mg, 35%) and a green zone of 9S (1:3
hexane–CH2Cl2, yield, 65%). Alternatively, the red so-
lution of 5S (0.2 mmol; 109.4 mg) in CHCl3 (20 ml) was
heated under reflux for 7 h, during which time the
colour changed gradually to green. The same work-up
procedure as described above gave 5S (yield, 35 mg,
32%) and 9S (yield, 43.8 mg, 40%). Recrystallisation
from CH2Cl2/hexane afforded violet crystals of 9S
1
11S: yield, 44.3 mg, 35%; m.p.=196°C (dec.). H-
NMR (CD2Cl2): l=1.12 (d, J=6.9 Hz, 3H,
CH(CH3)2), 1.21 (d, J=6.9 Hz, 3H, CH(CH3)2), 1.80
(s, 3H, CH3), 2.32 (sp, J=6.9 Hz, 1H, CH(CH3)2), 3.15
(d, J=2.5 Hz, 1H, PhCꢀCH2), 4.72 (dd, J1=1.1 Hz,
J2=6.0 Hz, 1H, C6H4), 4.75 (d, J=2.5 Hz, 1H,
PhCꢀCH2), 5.66 (dd, J1=1.4, J2=6.0 Hz, 1H, C6H4),
6.14 (dd, J1=1.36, J2=6.0 Hz, 1H, C6H4), 6.23 (dd,
J1=1.1, J2=6.0 Hz, 1H, C6H4), 7.11 (m, 1H, Ph), 7.25
(m, 2H, Ph) and 7.56 (m, 2H, Ph). 11B-NMR (CD2Cl2):
l= −2.6, −5.0, −6.0, −6.5, −8.2, −10.3, −11.5,
−20.0 (OsꢀB) (2:1:2:1:1:2:1). IR (KBr): 2546, 2568,
2585, 2602(wBꢀH). EI-MS (70 eV): 633 [M+, 30%], 531
[M+−(PhCꢁCH), 100%].
4.9. Crystal structures of 5S, 6Se, 9S and 10S
1
(m.p.=167°C). H-NMR (CD2Cl2): l=1.38 (s, 15H,
Cp*), 2.41 (d, J=14.7 Hz, 1H, PhCꢀCH2), 2.56 (d,
J=14.7 Hz, 1H, PhCꢀCH2), 7.00 (m, 2H, Ph), 7.12 (m,
1H, Ph) and 7.30 (m, 2H, Ph). 11B-NMR (CD2Cl2):
l=1.6 (BꢀCH2), −7.1, −8.0, −9.5, −10.9, −14.2
(1:1:1:5:1:1). 103Rh-NMR (CD2Cl2): l=32991. IR
(KBr): 2571, 2580, 2602(wBꢀH). EI-MS (70 eV): 547
[M+, 100%].
The reflection intensities were collected on a Siemens
P4 diffractometer (Mo–Ka radiation, u=71.073 pm,
graphite monochromated). Structure solution and refin-
ement was carried out with the program package
SHELXTL-PLUS V.5.1. Measuring temperature for all
structure determinations was 296 K. All non-hydrogen
atoms were refined with anisotropic temperature fac-
tors. The hydrogen atoms at the boron atoms have
been located from difference Fourier syntheses. The
remaining hydrogen atoms are on calculated positions.
All hydrogen atoms were refined applying the riding
model with fixed isotropic temperature factors.
4.8. Preparation of 10S and 11S
The solution of either 3S (88.4 mg, 0.2 mmol) or 4S
(106 mg, 0.2 mmol) and phenylacetylene (0.2 ml, 2
mmol) in CHCl3 (30 ml) was stirred under reflux for 22
h (10S) or 36 h (11S). The colour changed gradually to
brown–red. In the case of ruthenium, the NMR spectra
showed the presence of ca. 90% of 10S and 10% of 7S
in the reaction mixture. The more soluble 7S was
removed from 10S by washing the solid carefully with
CH2Cl2. In the case of osmium, a first separation of
comparable amounts of 8S and 11S was carried out by
chromatography on silica gel (Merck, Kieselgel 60). By
elution with 1:1 hexane–CH2Cl2, an extended zone of
8S was obtained first, followed by a mixture of 8S
(minor) and 11S (major). A complete removal of 8S
from 11S was then achieved in the same way as de-
scribed above.
4.9.1. Crystal structure of 5S
C20H31B10S2Rh·0.3CHCl3, red platelet with dimen-
sions 0.30×0.18×0.06 mm crystallises in the triclinic
(
space group P1 with the lattice parameters a=
1112.35(12), b=1509.78(11), c=1746.62(12) pm, h=
90.910(6), i=102.405(7), k=90.522(7)°, V=2864.2(4)
106 pm3, Z=4, v=0.845 mm−1; 11 712 reflections
collected in the range 3°52q550°, 10 038 reflections
independent, 8109 assigned to be observed [I\2|(I)],
full-matrix least-squares refinement against F2 with 621
parameters converged at R1/wR2 values of 0.077/0.207,
empirical absorption correction (C-scans) resulted in
min./max. transmission factors of 0.3087/0.3747, the
max./min. residual electron density was 4.680/−1.822
1
10S: Yield, 65.3 mg, 60%; m.p.=168°C (dec.). H-
NMR (CD2Cl2): l=1.19 (d, J=6.8 Hz, 3H,
10−6 e pm−3
.

M. Herberhold et al. / Journal of Organometallic Chemistry 604 (2000) 170–177
177
5. Supplementary material
4.9.2. Crystal structure of 6Se
C20H31B10Se2Ir·0.5CH2Cl2, irregularly shaped, orange
crystal with dimensions 0.25×0.18×0.12 mm crys-
tallises in the monoclinic space group P21/n with the
lattice parameters a=1510.18(11), b=1009.66(7), c=
1952.18(19) pm, i=95.023(7)°, V=2965.2(4) 106 pm3,
Z=4, v=7.058 mm−1; 6501 reflections collected in
the range 3°52q550°, 5176 reflections independent,
4029 assigned to be observed [I\2|(I)], full-matrix
least-squares refinement against F2 with 325 parameters
converged at R1/wR2 values of 0.043/0.114; empirical
absorption correction (C-scans) resulted in min./max.
transmission factors of 0.4095/0.9473, the max./min.
Crystallographic data (excluding structure factors)
for the structures reported in this paper have been
deposited with the Cambridge Crystallographic Data
Centre as supplementary publications no. CCDC-
138360 (5S), -138359 (6Se), -138362 (9S) and -138361
(10S). Copies of the data can be obtained free of charge
on application to CCDC, 12 Union Road, Cambridge
CB2 1EZ, UK [fax: +44-(0)1223-336033; e-mail:
deposit@ccdc.cam.ac.uk].
Acknowledgements
residual electron density was 0.204/−1.01 10−6
pm−3
e
.
Support of this work by the Deutsche Forschungsge-
meinschaft and the Fonds der Chemischen Industrie is
gratefully acknowledged.
4.9.3. Crystal structure of 9S
C20H31B10S2Rh, dark red prism of dimensions 0.30×
0.18×0.15 mm crystallises in the triclinic space group
(
P1 with the lattice parameters a=1182.0(3), b=
References
1344.6(2), c=1733.5(3) pm, h=93.154(8), i=
105.267(9), k=103.760(8)°, V=2561.2(8) 106 pm3,
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the range 3°52q555°, 11 781 reflections independent,
8986 assigned to be observed [I\2|(I)], full-matrix
least-squares refinement against F2 with 596 parameters
converged at R1/wR2 values of 0.043/0.105, empirical
absorption correction (C-scans) yielded min./max.
transmission factors of 0.3534/0.4000, the max./min.
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pm−3
.
.