Carborane complexes of ruthenium: Studies on the chemistry of the Ru(CO)2(η5-7,8-Me2-7,8-C2B 9H9) fragment and the X-ray crystal structure of [NEt4][Ru2(μ-Tl)(CO)4(η 5-7,8-Me2-7,8-C2B9H 9)2]

Article abstract of DOI:10.1016/S0022-328X(97)00427-0

Reactions between Tl[closo-1,2-Me₂-3,1,2-TlC₂B₉H₉] and [RuBr(CO)₃(η³-C₃H₅)] in tetrahydrofuran (THF) affords mixtures of the compounds [Ru(CO)₃(η⁵-7,8-Me₂-7,8-C₂B ₉H₉)] (1b) and Tl[Ru₂(μ-Tl)(CO)₄(η⁵-7,8-Me ₂-7,8-C₂B₉H₉)₂] (2a) in a ratio 2:3. Treatment of the mixtures with [NEt₄]I followed by I₂ produces [NEt₄][RuI(CO)₂(η⁵-7,8-Me ₂-7,8-C₂B₉H₉)] (3b) as the only product. Complex 2a, isolated as the [NEt₄]⁺ salt 2b, was the subject of a single-crystal X-ray diffraction analysis. The compound crystallises in the orthorhombic space group Pbcn [a=23.164(2), b=13.780(2), c=11.560(6) A]. The structure of the anion consists of two Ru(CO)₂(η⁵-7,8-Me₂-7,8-C₂B ₉H₉) fragments linked together via a thallium atom, with the complex carrying an overall uninegative charge. The synthon [Ru(THF)(CO)₂(η⁵-7,8-Me₂-7,8-C ₂B₉H₉)] (4b) is readily generated from 3b by the addition of AgBF₄ in THF. The same procedure in MeCN produces the complex [Ru(NCMe)(CO)₂(η⁵-7,8-Me₂-7,8-C ₂B₉H₉)] (4c). The removal of THF from 4b in vacuo gave the 16-electron complex [Ru(CO)₂(η⁵-7,8-Me₂-7,8-C₂B ₉H₉)] and a polymeric material postulated to be [Ru(CO)₂(η⁵-7,8-Me₂-7,8-C₂B ₉H₉)]_n. Reaction of solutions of 4b in CH₂Cl₂ with 2-electron donor ligands yields the complexes [Ru(L)(CO)₂(η⁵-7,8-Me₂-7,8-C ₂B₉H₉)] (4d, L=PPh₃; 4e, L=CNBu^t; 4f, L=NC₅H₅). Addition of alkenes and alkynes to CH₂Cl₂ solutions of 4b did not give stable η²-adducts, but the species [Ru(CO)₂(η⁵-7,8-Me₂-7,8-C₂B ₉H₉)] was observed in these reactions. The complex [Ru(CO)₂(η²,η⁵-7,8-Me ₂-10-C(H)=C(H)SiMe₃-7,8-C₂B₉H ₉)] (5a) was isolated from the reaction between 4b and Me₃SiCCH. The IR and NMR spectra of the new compounds are reported.

Full text of DOI:10.1016/S0022-328X(97)00427-0

Ž
.
Journal of Organometallic Chemistry 551 1998 27–36
Carborane complexes of ruthenium: studies on the chemistry of the
5
ž
/ ž
/
Ru CO h -7,8-Me2-7,8-C2 B9H9 fragment and the X-ray crystal
2
5
1,2
w
xw / x
ž
/ ž
b
/ ž
structure of NEt4 Ru2 m-Tl CO h -7,8-Me2-7,8-C2 B9H9 2
4
a
b
b,)
John C. Jeffery , Paul A. Jelliss , Yi-Hsien Liao , F. Gordon A. Stone
a
School of Chemistry, UniÕersity of Bristol, Bristol BS8 1TS, UK
Department of Chemistry, Baylor UniÕersity, Waco, TX 76798-7348, USA
b
Received 22 April 1997; revised 8 June 1997; accepted 8 June 1997
Abstract
3
w
x
w
Ž
. Ž
.x
Ž
.
Reactions between Tl closo-1,2-Me2-3,1,2-TlC2B9H9 and RuBr CO h -C3H5 in tetrahydrofuran THF affords mixtures of the
3
5
5
w
Ž
. Ž
compounds Ru CO h -7,8-Me2-7,8-C2B9H9 1b and Tl Ru2 m-Tl CO h -7,8-Me2-7,8-C2B9H9
2
.x Ž
.
w
w
Ž
.Ž . Ž
. x Ž
.
2a in a ratio 2:3. Treatment
3
w
4
5
x
xw
xq
salt 2b, was the subject of a single-crystal X-ray diffraction analysis. The compound crystallises in the
Ž
. Ž
.x Ž
.
of the mixtures with NEt4 I followed by I2 produces NEt4 RuI CO h -7,8-Me2-7,8-C2B9H9 3b as the only product. Complex 2a,
2
w
isolated as the NEt4
orthorhombic space group Pbcn as23.164 2 , bs13.780 2 , cs11.560 6 A . The structure of the anion consists of two
˚
x
w
Ž .
Ž .
Ž .
5
Ž
. Ž
.
Ru CO h -7,8-Me2-7,8-C2B9H9 fragments linked together via a thallium atom, with the complex carrying an overall uninegative
2
5
w
Ž
.Ž . Ž
.x Ž
.Ž . Ž
.
charge. The synthon Ru THF CO h -7,8-Me2-7,8-C2B9H9 4b is readily generated from 3b by the addition of AgBF4 in THF. The
same procedure in MeCN produces the complex Ru NCMe CO h -7,8-Me2-7,8-C2B9H9 4c . The removal of THF from 4b in
vacuo gave the 16-electron complex Ru CO h -7,8-Me2-7,8-C2B9H9 and a polymeric material postulated to be Ru CO h -7,8-
Me2-7,8-C2B9H9 n. Reaction of solutions of 4b in CH2Cl2 with 2-electron donor ligands yields the complexes Ru L CO h -7,8-
2
5
w
Ž
.x Ž
.
2
5
5
w
Ž
. Ž
.x
w
Ž
. Ž
2
.x
w
Ž .Ž .2Ž
5
2
t
.x Ž
.
Me2-7,8-C2B9H9 4d, LsPPh3; 4e, LsCNBu ; 4f, LsNC5H5 . Addition of alkenes and alkynes to CH2Cl2 solutions of 4b did not
give stable h2-adducts, but the species Ru CO h -7,8-Me2-7,8-C2B9H9 was observed in these reactions. The complex
5
w
Ž
. Ž
.x
2
2
5
w
Ž
. Ž
Ž . Ž .
.x Ž .
Ru CO h ,h -7,8-Me2-10-C H 5C H SiMe3-7,8-C2B9H9 5a was isolated from the reaction between 4b and Me3SiC[CH. The IR
and NMR spectra of the new compounds are reported. q 1998 Elsevier Science S.A.
2
Keywords: Metallacarborane; Ruthenium; Carbonyl
1. Introduction
provides an interesting variant in such reactions of
metallacarborane compounds. Therefore, the next logi-
cal step in our investigation of the reactivity of
We have thoroughly investigated the chemistry of the
5
Ž
. Ž
.
fragment Ru CO h -7,8-C2 B9 H11 and found it yields
ruthenacarborane complexes was to examine the be-
2
5
a plethora of novel compounds upon reaction with both
Ž
. Ž
.
haviour of the Ru CO h -7,8-Me2-7,8-C2 B9 H9 moi-
2
w
x
organic and organometallic reagents 1–3 . Previous
work has often led us to observe that the replacement of
the CH groups on the carborane ligand by CMe groups
ety . In d eed, reaction s o f th e sp ecies
5
w
Ž
.Ž . Ž
.x
Ru THF CO h -7,8-Me2-7,8-C2 B9 H9 with tung-
3
sten– and molybdenum–alkylidynes have produced
w x
some remarkable results 3 . We also wished to study
reactions with simple 2-electron donor molecules, for
)
Corresponding author.
the purpose of comparison with results obtained in the
1 This paper is dedicated to Professor P.M. Maitlis FRS on the
occasion of his 65th birthday.
5
Ž
. Ž
.
Ru CO h -7,8-C2 B9 H11 work.
2
2 The compounds described in this paper have a ruthenium atom
incorporated into a closo-1,2-carba-3-ruthenadodecaborane structure.
However, to avoid a complicated nomenclature for the complexes
reported, and to relate them to the many known ruthenium species
with h5-coordinated cyclopentadienyl ligands, we treat the cages as
nido-11-vertex ligands with numbering as for an icosahedron from
which the twelfth vertex has been removed.
2. Results and discussion
The synthetic route to the reactive synthon
5
w
Ž
.Ž . Ž
.
x
Ž
.
Ru THF CO h -7,8-C2 B9 H11 4a is displayed in
2
Scheme 1.The first step involves the reaction of
0022-328Xr98r$19.00 q 1998 Elsevier Science S.A. All rights reserved.

(
)
28
J.C. Jeffery et al.rJournal of Organometallic Chemistry 551 1998 27–36

(
)
J.C. Jeffery et al.rJournal of Organometallic Chemistry 551 1998 27–36
29
w
Ž
.12 x
with nido-7,8-C2 B9 H13 in refluxing hep-
Ru3 CO
tane to give Ru CO h -7,8-C2 B9 H11 1a , formed
5
w
Ž
. Ž
.
x
Ž
.
3
w x
as the only product and in good yield 1 . When repeat-
ing this methodology using nido-7,8-Me2-7,8-C2 B9 H11,
a
mixture of the trinuclear metal complex
5
w
Ž
. Ž
.x
3
Ru3 CO h -7,8-Me2-7,8-C2 B9 H9 and the desired
mononuclear complex Ru CO h -7,8-Me2-7,8-
8
5
w
Ž
. Ž
.
x
Ž
.
Ž
. w x
C2 B9 H9 1b was formed in ratio 9:1 Scheme 1 4 .
Thus, this method is rendered impractical for the pur-
pose of producing 1b as a precursor to other complexes,
even though the two reaction products are readily sepa-
rated by column chromatography. Our initial studies of
reactions of 1b with alkylidyne–molybdenum and
–tungsten complexes did, however, rely on obtaining
5
w
xw
Ž
.Ž . Ž
4
Fig. 1. Structure of the anion of NEt4 Ru2 m-Tl CO h -7,8-
. x Ž
.
Me2-7,8-C2 B9 H9
2b , showing the crystallographic labeling
scheme. Hydrogen atoms are omitted for clarity and thermal ellip-
2
w x
the mononuclear species by this route 3 .
soids are shown at the 40% probability level.
w
w
xw
Ä
Ž
.
1642
Ž
.
x w
Ž . Ž .
m4-Tl 2.780 3 and 2.864 2
AsPh4 Ru6C CO
˚
x w x
A
5 . If bonding in complex 2b were considered to
Ž .1y
involve purely ionic interactions between two Ru II
fragments and a Tl I
previously synthesised thallium I -transition metal com-
plexes, longer Tl–Ru interactions in 2b might have
been expected. It has been proposed that in the complex
Ž .1q
ion, as has been postulated for
Ž .
w
Ž
.
Ä
Ž
.
4
Ž
. Ž x
.
xw
salt Ir2 m-Tl m- PPh2CH2 2 AsPh Cl CO NO3
2
2
2
w x
6 , a significant covalent interaction between the filled
5dz2 orbitals and empty 6pz on the iridium atoms with
the filled 6s and empty 6py and 6pz orbitals on the
thallium atom leads to enhanced stability of the system
and thus to short Tl–Ir bonds. A similar situation can be
envisaged in 2b, possibly utilizing filled 4d and empty
5p orbitals of suitable symmetry on the ruthenium atoms
with the filled 6s and empty 6p orbitals on the thallium
atom. It should be noted that the Ir–Tl–Ir bond angle in
w
Ž
.
Ä
Ž
.
4
Ž
. Ž
.
xw
x
Ir2 m-Tl m- PPh2CH2 2 AsPh Cl CO NO3 is
2
2
2
Table 1
˚
Ž .
Ž
.
Selected internuclear distances A and angles deg for 2b with estimated standard deviations in parentheses
Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž .
Ru 1 –C 1 2.270 3 Ru 1 –C 2 2.276 4 Ru 1 –B 3 2.284 4
Ž . Ž .
Ru 1 –B 4
Ž .
2.244 4
Tl 1 –Ru 1 2.5994 4 Ru 1 –C 4 1.857 4 Ru 1 –C 3 1.911 4
Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž .
Ru 1 –B 5
Ž . Ž .
Ž .
2.294 4
Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž .
Ž
.
Ž . Ž .
Ž .
1.723 5
C 1 –C 10 1.532 5 C 1 –C 2 1.682 5 C 1 –B 6 1.715 6
C 1 –B 5
Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž .
Ž
.
Ž . Ž .
Ž .
1.713 5
C 1 –B 7 1.733 6 C 2 –C 20 1.528 5 C 2 –B 8 1.708 6
C 2 –B 3
Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž .
Ž . Ž .
B 5 –B 10
Ž .
1.829 6
C 2 –B 7 1.730 6 B 3 –B 8 1.765 6 B 3 –B 9 1.769 6
B 3 –B 4
Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž .
Ž
.
Ž .
Ž
.
.
.
Ž .
1.789 6
B 4 –B 9 1.784 6 B 4 –B 10 1.790 6 B 4 –B 5 1.829 6
Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž .
Ž
.
Ž .
B 8 –B 11
Ž . Ž .
C 3 –O 3
Ž
Ž .
1.765 6
B 5 –B 6 1.793 6 B 6 –B 7 1.750 7 B 6 –B 11 1.769 7
B 6 –B 10
Ž . Ž . Ž . Ž . Ž . Ž . Ž . Ž .
Ž
Ž
.
.
Ž .
Ž
Ž .
1.762 7
B 7 –B 8 1.751 7 B 7 –B 11 1.757 7 B 8 –B 9 1.760 7
Ž . Ž . Ž . Ž . Ž .
Ž
.
Ž . Ž .
B 10 –B 11
Ž .
1.136 6
B 9 –B 11 1.766 6 B 9 –B 10 1.782 7 1.777 7
Ž . Ž .
Ž .
C 4 –O 4 1.154 5
Ž . Ž . Ž .
Ž
.
Ž .
Ž . Ž .
Ž .
89.5 2
115.5 2
Ž .
Ž . Ž .
Ž .
86.5 2
Ru 1 –Tl 1 –Ru 1A 165.67 2
C 4 –Ru 1 –C 3
C 4 –Ru 1 –B 5
Ž . Ž . Ž . Ž .
Ž .
Ž . Ž .
Ž .
Ž .
Ž . Ž .
Ž .
104.0 2
C 3 –Ru 1 –B 5 140.5 2
C 4 –Ru 1 –C 1
C 3 –Ru 1 –C 1
Ž .
Ž . Ž .
Ž
.
.
Ž . Ž . Ž .
Ž .
Ž . Ž . Ž .
Ž .
96.2 2
B 5 –Ru 1 –C 1
44.88 14
C 4 –Ru 1 –C 2
159.0 2
C 3 –Ru 1 –C 2
Ž . Ž . Ž .
Ž
Ž . Ž . Ž .
Ž
.
Ž . Ž . Ž .
Ž .
144.3 2
B 5 –Ru 1 –C 2
76.23 14
C 1 –Ru 1 –C 2
Ž . Ž . Ž .
43.44 13
C 4 –Ru 1 –B 3
Ž . Ž . Ž .
Ž . Ž . Ž .
Ž .
Ž .
Ž
.
C 3 –Ru 1 –B 3
Ž . Ž . Ž .
121.8 2
B 5 –Ru 1 –B 3
Ž . Ž . Ž .
79.4 2
C 1 –Ru 1 –B 3
Ž . Ž . Ž .
75.93 14
Ž .
168.5 2
Ž
.
.
Ž .
C 2 –Ru 1 –B 3
Ž . Ž . Ž .
44.12 13
Ž .
C 4 –Ru 1 –B 4
100.1 2
C 3 –Ru 1 –B 4
Ž . Ž . Ž .
Ž
.
.
Ž . Ž . Ž .
Ž
77.07 14
.
.
B 5 –Ru 1 –B 4
47.5 2
C 1 –Ru 1 –B 4
77.63 14
C 2 –Ru 1 –B 4
Ž . Ž . Ž .
Ž
Ž . Ž . Ž .
Ž
Ž . Ž . Ž .
Ž
90.95 12
B 3 –Ru 1 –B 4
47.10 14
C 4 –Ru 1 –Tl 1
Ž . Ž . Ž .
88.37 13
C 3 –Ru 1 –Tl 1
Ž . Ž . Ž .
Ž . Ž . Ž .
Ž
.
Ž
.
Ž .
111.68 9
B 5 –Ru 1 –Tl 1
Ž . Ž . Ž .
128.17 11
C 1 –Ru 1 –Tl 1
Ž . Ž . Ž .
151.41 10 C 2 –Ru 1 –Tl 1
Ž
.
Ž
.
Ž . Ž . Ž .
O 3 –C 3 –Ru 1
Ž .
178.3 4
B 3 –Ru 1 –Tl 1
Ž . Ž . Ž .
75.48 10
Ž .
176.5 4
B 4 –Ru 1 –Tl 1
83.09 10
O 4 –C 4 –Ru 1

(
)
30
J.C. Jeffery et al.rJournal of Organometallic Chemistry 551 1998 27–36
11
Ž .
Ä1
4
distinctly bent at 139.4 1 8, but in this complex the
ture B H NMR spectrum showed a pattern of broad
Ž
.
iridiums are constrained within two near-parallel
square-planar systems. In complex 2b, the Ru 1 –
signals 1:2:3:1:2 consistent with two equivalent nido-
C2 B9 cages with a mirror plane of symmetry.
Returning to the synthesis of 2a, it will be recalled
that this salt is formed with complex 1b in ratio ca. 3:2.
If this mixture is treated with NEt4 I in refluxing
tetrahydrofuran THF , 1b is converted to
Ž .
Ž .
Ž
.
Tl 1 –Ru 1A angle is less deviated from linearity at
Ž .
165.67 2 8.
The analytical and NMR data for complex 2b are
given in Tables 2 and 3. The IR spectrum showed three
w
x
Ž
.
5
Ž
.
w
xw
Ž
. Ž
.
x
Ž
.
terminal nmax CO absorption bands at 2014, 1992, and
NEt4 RuI CO h -7,8-Me2-7,8-C2 B9 H9 3b , while
2
1
1954 cmy1. In the H NMR spectrum, one signal is
2a is converted to 2b, as assessed by IR spectroscopy.
At this point, the mixture is cooled to 08C and treated
very carefully with I2 to convert 2b to 3b which, in this
manner, is formed as the sole product and in high yield.
Hence, a one-pot synthesis of the useful reagent 3b
observed for the cage methyl protons at d 2.21, while
13
Ä1
4
in the C H NMR spectrum, two signals are noted at
d 68.8 and 32.8 for the cage CMe and C Me carbon
nuclei, respectively, the former being characteristically
broad. A single very broad peak due to the carbonyl
w
x
from Tl closo-1,2-Me2-3,1,2-TlC 2 B 9 H 9
and
3
w
Ž
. Ž
.
x
Ž
ligands was observed in the range d 195–200. A vari-
RuBr CO h -C3H5 has become available Scheme
3
13
Ä1
4
.
able temperature C H NMR experiment revealed
that this peak sharpened up somewhat in spectra mea-
sured down to y558C. It is suggested that the broad-
ness of the peak at ambient temperature may be due to
2 . The mechanism of the reaction of 2b with I2 is
unclear, but may involve the intermediacy of the disso-
ciation fragments RuTl CO h -7,8-Me2-7,8-
C2 B9 H9
mentioned above.
5
w
Ž
. Ž
2
5
.
xy
w
Ž
. Ž .x
and Ru CO h -7,8-Me2-7,8-C2 B9 H9
2
partial dissociation of the anion of 2b in solution into
RuTl CO h -7,8-Me2-7,8-C2 B9 H9
5
w
Ž
. Ž
.
xy
and a neutral
Complex 3b is a new compound and was charac-
terised by standard spectroscopic and analytical tech-
niques; data are listed in Tables 2 and 3. The IR
spectrum revealed two terminal CO bands at 2034 and
2
5
w
Ž
. Ž
16-electron species Ru CO h -7,8-Me2-7,8-
2
.
x
C2 B9 H9 , the existence of the latter having basis in
chemistry discussed shortly. It was noted that the signal
due to the cage carbon CMe nuclei at y558C was also
considerably sharper than in the corresponding room-
temperature spectrum. The C Me carbon and proton
nuclei showed less enhanced signal sharpening in the
low-temperature spectra. To account for the broadness
in the spectra at ambient temperatures, the
dissociation–reassociation process must be occurring at
or near the NMR time scale. Unfortunately it was not
possible to study this phenomenon at elevated tempera-
tures because of the absence of suitable NMR solvents
in which the compound is soluble. The room-tempera-
1
1984 cmy1
, as expected. In the H NMR spectrum, a
singlet resonance was observed for the cage methyl
13
Ä1
4
groups at d 2.34, while signals in the C H NMR
spectrum at d 198.4, 71.2, and 33.6 confirmed the
presence of the equivalent carbonyl ligands, and the
cage carbon and cage methyl nuclei, respectively.
The treatment of the salt 3b with AgBF in THF
produces the solvent adduct Ru THF CO h -7,8-
Me2-7,8-C2 B9 H9
studied complex 4a 1 . The IR spectrum of 4b in THF
shows strong nmax CO absorptions at 2044 and 1994
4
5
w
Ž
.Ž . Ž
2
.
x
Ž
.
4b , an analog of the previously
w x
Ž
.
Table 2
Analytical and physical data
y1
c
Compounda
nmax CO cm
Yield % Analysis %
C
Ž
.b Ž
.
Ž
.
Ž .
H
N
5
w
w
w
w
w
w
w
w
xw
Ž
.Ž . Ž
. x Ž
.
2b
Ž . Ž . Ž
24.4 24.8 5.2 5.2 1.4 1.4
.
.
NEt4 Ru2 m-Tl CO h -7,8-Me2-7,8-C2 B9 H9
2014 m, 1992 s, 1995 m 33
4
2
5
xw
Ž
. Ž
.x Ž
.
Ž . Ž . Ž
28.8 29.3 5.8 6.1 2.0 2.4
NEt4 RuI CO h -7,8-Me2-7,8-C2 B9 H9 3b
Ru THF CO h -7,8-Me2-7,8-C2 B9 H9 4b
Ru NCMe CO h -7,8-Me2-7,8-C2 B9 H9 4c
Ru PPh3 CO h -7,8-Me2-7,8-C2 B9 H9 4d
Ru CNBu CO h -7,8-Me2-7,8-C2 B9 H9 4e
Ru NC5H5 CO h -7,8-Me2-7,8-C2 B9 H9 4f
Ru CO h ,h -7,8-Me2-10-C H 5C H SiMe3-7,8-C2 B9 H8 5a 2042 s, 1994 s
2034 s, 1984 s
2044 s, 1994 se
2060 s, 2014 s
2040 s, 1990 s
2066 s, 2022 sf
2050 s, 1998 s
97
62
78
51
85
87
21
2
5
d
Ž
.Ž . Ž
.x Ž
.
5
Ž
.Ž 2 . Ž
.x Ž
.
Ž . Ž . Ž
26.9 26.8 5.1 5.0 3.9 3.9
.
2
5
Ž
.Ž . Ž
.x Ž
.
Ž . Ž
49.3 49.7 5.2 5.2
32.7 33.0 6.2 6.0 3.4 3.5
.
.
5
Ž
t.Ž 2. Ž
.x Ž
.
.
Ž
.
Ž
Ž
Ž
.
.
2
5
Ž
.Ž . Ž
.x Ž
Ž
.
Ž
.
33.2 33.3 5.1 5.1 3.5 3.5
2
2
5
Ž
. Ä
Ž . Ž .
4xŽ
.
Ž
.
Ž
.
31.9 31.8 6.1 6.1
2
aAll complexes are yellow in colour except 3b, which is red.
b Measured in CH2Cl2 unless otherwise stated. A medium-intensity broad band observed at ca. 2550 cmy1 in the spectra of all the compounds is
due to B–H absorptions.
cCalculated values are given in parentheses.
d When samples are dried in vacuo, THF is lost with some decomposition: microanalysis not available. While it was not possible to obtain the
5
w
Ž
. Ž
.x
16-electron complex Ru CO h -7,8-Me2-7,8-C2 B9 H9 in sufficient purity for microanalysis, an EI mass spectrum was measured: 318.10
2
Ž
.
Ž
.
Ž
33% relative peak height, parent molecular ion, calc. 318.02 , 290.03 71% relative peak height, –CO=1 , 262.04 100% relative peak height,
.
–CO=2 .
e Measured in THF solution.
f
y1
Ž
.
nmax NC 2186 cm
.

Table 3
Hydrogen-1, carbon-13 and boron-11 NMR dataa
1
b
13
c
11
d
Ž
.
Ž
.
Ž .
B d
Compound
H d
C d
2be
1.39 t of t, 12 H, Me, J HH s7, J NH s2 ,
197.8 v br, CO , 68.8 br, cage C ,
w
Ž
.
Ž
.
x
Ž
.
Ž
.
Ž . Ž . Ž .
y1.2 1 B , y5.8 2 B , y9.4 3 B ,
Ž
.
w
Ž
.
x
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
2.21 s, 12 H, cage Me , 3.47 q, 8 H, CH2 , J HH s7
53.0 CH2 , 32.8 cage Me , 7.7 Me
y11.7 1 B , y15.1 2 B
w
Ž
.
w
Ž
.
x
Ž
.
Ž
.
Ž
.
Ž . Ž . Ž .
1.1 1 B , y5.1 2 B , y9.9 4 B ,
3b
1.34 t of t, 12 H, Me, J HH s7, J NH s2 ,
198.4 CO , 71.2 br, cage C , 53.1 CH2
,
Ž
.
Ž
.
x
Ž
.
Ž
.
Ž
.
2.34 s, 6 H, cage Me , 3.21 q, 8 H, CH2 , J HH s7
33.6 cage Me , 7.8 Me
y16.4 2 B
4bf
4c
1.79 m, 4 H, CH2 , 1.83 s, 6 H, cage Me ,
196.9 CO , 79.1 cage C , 68.0 CH2O ,
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž . Ž . Ž . Ž .
5.1 1 B , y4.7 2 B , y8.6 2 B , y9.8 1 B ,
Ž
.
Ž
.
Ž
.
Ž
.
3.63 m, 4 H, CH2O
26.1 cage Me and CH2
y13.3 1 B , y15.4 2 B
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž . Ž . Ž .
5.6 1 B , y4.5 2 B , y8.2 2 B ,
1.95 s, 6 H, cage Me , 2.39 s, 3 H, Me
194.8 CO , 121.3 CN , 76.8 cage C ,
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
28.5 cage Me , 4.2 Me
y9.9 1 B , y10.9 1 B , y14.8 2 B
4dg
2.07 s, 6 H, cage Me , 7.40 – 7.68 m, 15 H, Ph
197.0 d, CO, J PC s16 ,
Ž
.
Ž
.
w
Ž
.
.
x
Ž . Ž . Ž .
3.4 1 B , y2.4 1 B , y4.0 2 B ,
w
2Ž
Ž
.
x
w
1Ž
.
Ž
.
Ž
.
133.9 d, C Ph , J PC s10 , 132.6 d, C Ph ,
y6.5 3 B , y12.0 2 B
Ž
.
x
w
4Ž
.
Ž
.
x
J PC s53 , 131.5 d, C Ph , J PC s3 ,
w
3Ž
.
Ž
.
x
128.9 d, C Ph , J PC s11 ,
Ž
.
Ž
.
Ž . Ž . Ž . Ž . Ž
3.4 1 B , y2.4 1 B , y4.0 2 B , y6.5 3 B , y12.0 2
71.8 cage C , 31.3 cage Me
Ž
.
Ž
.
Ž
.
w
Ž
.
x
Ž . Ž . Ž .
5.1 1 B , y4.5 2 B , y6.3 1 B ,
4e
1.57 s, 9 H, Me , 2.16 s, 6 H, cage Me
193.7 CO , 137.2 t, NC, J NC s20 ,
Ž
Ž
.
.
Ž
.
Ž
.
Ž
.
Ž
.
Ž
.
74.3 cage C , 59.9 CMe3 , 31.9 cage Me ,
y7.0 2 B , y9.2 1 B , y13.2 2 B
30.1 C Me3
4f e
5a
1.75 s, 6 H, cage Me , 7.74 m, 2 H, NC5H5
,
197.2 CO , 156.9, 140.8, 128.1 2C:1C:2C,
Ž
.
Ž
.
Ž
.
Ž
Ž . Ž . Ž .
7.1 1 B , y2.8 2B , y5.2 2 B ,
Ž
.
.
Ž
.
Ž
.
Ž
.
Ž
.
8.21 m, 1 H, NC5H5
,
NC5H5 , 73.4 cage C , 27.7 cage Me
y6.7 2 B , y10.9 2 B
Ž
.
9.06 m, 2 H, NC5H5
h
Ž
.
Ž
.
w
Ž . x
x
w
Ž .
x
Ž
.
Ž
.
0.27 s, 9 H, SiMe3
,
196.7, 193.7 CO , 98.5 vbr,5C H B ,
82.7 cage C , 75.8 5C H SiMe3
67.5 cage C , 32.3, 31.4 cage Me ,
19.2 1 B, BC H 5C , 2.4 1 B , y2.2 1 B ,
w
Ž
.
Ž
Ž
.
w
Ž .
Ž . Ž . Ž .
y3.5 1 B , y7.4 1 B , y9.6 2 B ,
3.76 d, 1 H,5C H SiMe3,
,
.
Ž
.
x
w
Ž
.
Ž
.
x
.
Ž
Ž
.
Ž
.
J HH s15 , 4.94 d, 1 H,5C H B, J HH s15
y11.3 1 B , y12.7 1 B
Ž
.
y0.7 SiMe3
a
Ž
.
Ž .
in ppm, coupling constants J in Hz, measurements at ambient temperature in CD2Cl2 unless otherwise stated.
Chemical shifts
d
bResonances for terminal BH protons occur as broad unresolved signals in the range of d ca. y2 to 3.
c Hydrogen-1 decoupled, chemical shifts are positive to high frequency of SiMe4.
d Hydrogen-1 decoupled, chemical shifts are positive to high frequency of BF3 ØOEt2 external .
Ž
.
e Measurements in d6-acetone.
f
Ž
.
Measurement in CD2Cl2 –THF 10:1 .
g31
Ä1
4
P
H NMR: d 45.7.
h Identified in a fully coupled 11 B NMR spectrum.

(
)
32
J.C. Jeffery et al.rJournal of Organometallic Chemistry 551 1998 27–36
w x
determined by an X-ray powder diffraction study 8 .
Polymeric transition metal carbonyl complexes are few
in number, but clearly there is some capacity for ruthe-
nium carbonyl units to undergo this kind of chain
aggregation. The nature of the polymeric species
5
w
Ž
. Ž
.
xn
Ru CO h -7,8-Me2-7,8-C2 B9 H9
is unknown. An
2
EI mass spectrum of this orange material clearly shows
a parent molecular ion peak for the 16-electron moiety
5
w
Ž
. Ž
.x
Ru CO h -7,8-Me2-7,8-C2 B9 H9 at 318.10, with
2
two further peaks at 290.03 and 262.04 due to molecu-
lar ions resulting from loss of one and two CO ligands,
respectively, from the parent. There was no mass spec-
1
tral evidence for any molecular ions with n)1. A H
NMR spectrum of the weak solution formed upon addi-
tion of CD2Cl2 indicated that no THF was present in
11
Ä1
4
the sample. An B H NMR spectrum of the same
solution was complex, and contained additional peaks in
the range d y30 to y40, which are almost certainly
due to a nido-cage species, indicating that some decom-
position has occurred. When THF is added to the
orange residue, most of the solid is taken up to form a
yellow solution, with some unidentified insoluble black
material remaining. An IR spectrum of the THF solu-
tion, shows it to contain only the adduct 4b. Hence, to
some extent THF dissociation is reversible.
If solutions of complex 4b generated in THF undergo
solvent removal in vacuo, the resulting residue can
subsequently be redissolved in CH2Cl2 , provided the
sample has not been evacuated for an extended period
of time. Dissolving 4b in CH2Cl2 also has the effect of
activating the complex towards reaction with other donor
molecules. NMR measurements were made on a sample
of complex 4b dissolved in CD2Cl2 with a very small
Scheme 2. New one-pot synthesis of the complex 4b.
1
cmy1. If THF is removed in vacuo, an orange residue
results, which, after drying for at least 24 h in vacuo,
shows only limited solubility in CH2Cl2. An IR spec-
trum of the weak solution produced reveals two princi-
pal peaks at 2060 and 2014 cmy1. The difference
between these frequencies and those for freshly pre-
pared THF solutions of 4b are too great to be attributed
to a ‘solvent change’ effect. Thus as was observed with
amount of added THF to stabilise the complex. The H
NMR spectrum revealed two sets of multiplets at d
1.79 and 3.63 due to the CH2 protons of the ligating
THF, which may be compared with the corresponding
1
Ž
.
signals in complex 4a d 1.99 and 3.90 . Also in the H
NMR spectrum of 4b, a single resonance for the cage
13
Ä1
4
CMe groups was observed at d 1.83. The C H
NMR spectrum showed two resonances for the ligated
THF at d 68.0 and 26.1, with singlet signals observed
for the CO, cage CMe and C Me carbon nuclei at d
196.9, 79.1, and 26.1, respectively, confirming the pres-
ence of a mirror plane containing the Ru atom, the THF
oxygen atom and the mid-point of the cage C–C con-
w x
4a 1 , loss of coordinated THF to give a 16-electron
5
w
Ž
. Ž
.x
complex Ru CO h -7,8-Me2-7,8-C2 B9 H9 is be-
2
lieved to occur. Two further weak peaks are also ob-
served in the IR spectrum of CH2Cl2 solutions of the
orange residue at 2070 and 2026 cmy1 and we believe
that these may be due to a polymeric species
nectivity.
5
5
w
Ž
. Ž
.
xn
w
Ž
.Ž . Ž
2
Ru CO h -7,8-Me2-7,8-C2 B9 H9
. Indeed this
The compound Ru NCMe CO h -7,8-Me2-7,8-
2
.
x
Ž
.
polymeric compound constitutes the bulk of the insolu-
ble material. A nujol mull IR spectrum of the solid
displays bands at 2066 and 2034 cmy1, which are
similar to the weaker set of peaks in the spectrum
measured on a CH2Cl2 solution. A polymeric form of
C2 B9 H9 4c , an analog of complex 4b, was readily
prepared by treating the salt 3b with AgBF in MeCN.
4
Ž
.
The IR spectrum showed nmax CO stretching bands at
2060 and 2014 cmy1. The NMR spectra revealed reso-
nances for the ligated MeCN molecule at d 2.39 in the
1
w
Ž
.4 x
Ž
.
Ž
.
ruthenium carbonyl, Ru CO n, has been isolated by
treatment of Ru3 CO
H spectrum and at 121.3 NCMe and 4.2 NC Me in
13
Ä1
4
Ž
.
solutions under CO with UV
the C H spectrum. The equivalent cage methyl
1w2
x
Ž1
.
irradiation or sunlight 7,8 , and its structure has been
groups also give rise to signals at d 1.95 H spectrum

(
)
J.C. Jeffery et al.rJournal of Organometallic Chemistry 551 1998 27–36
33
Ž13 Ä1
4 .
C H spectrum , with the cage carbon
Ž
.
and 28.5
nuclei showing the usual broad resonance at d 76.8 in
TLC , material in one of the yellow fractions was
2
5
w
Ž
. Ž
characterised as Ru CO h ,h -7,8-Me2-10-
C H 5C H SiMe3-7,8-C2 B9 H8 5a .
2
11
Ä1
4
Ž .
Ž .
.
x
Ž
.
the latter NMR spectrum. The B H NMR spectrum
1
Ž
.
was as expected Table 3 .
The H NMR spectrum of compound 5a showed two
The addition of PPh3, But NC, and pyridine to
w
Ž
.
sets of doublet signals at d 3.76 and 4.94 J HH s15
x
Ž .
Ž .
CH2Cl2 solutions of reagent 4b generates the stable
Hz corresponding to the trans C H 5C H protons.
As a result of the asymmetry of the system, two singlets
are observed in the 1H NMR spectrum for the cage
5
w
Ž .Ž . Ž
.x Ž
complexes Ru L CO h -7,8-Me2-7,8-C2 B9 H9 4d,
2
t
.
LsPPh3; 4e, LsCNBu ; 4f, LsNC5H5 , respec-
Ž
.
tively, all isolated in good yield after column chro-
methyl groups d 2.37 and 2.43 and four signals are
observed in the C H NMR spectrum at d 67.5
and 82.7 CMe and at 31.4 and 32.3 C Me . Also
in this spectrum, a broad resonance was observed at
d 98.5, and this may be assigned to the vinyl carbon
bound to one of the boron atoms in the metal-coordina-
13
Ä1
4
matography. All molecules possess Cs symmetry as
evidenced by their B H NMR spectra Table 3 .
Furthermore, the H and C H NMR spectra of the
complexes revealed single resonances for the cage car-
bon and cage methyl nuclei in addition to single peaks
for the CO carbon nuclei Table 3 . The P H NMR
spectrum of 4d showed the expected singlet for the
ligated phosphine at d 45.7. The spectra of compound
11
Ä1
4
Ž
.
Ž
.
Ž
.
1
13
Ä1
4
31
Ž
.
Ä1
4
ting
face of the cage. The other vinyl carbon,
to which the SiMe3 group is bound, displayed a signal
at d 75.8. The B H NMR spectrum showed a
resonance at d 19.2, which is attributable to the cage
11
Ä1
4
Ž
.
4e were as expected with a nmax NC band in the IR
spectrum at 2186 cmy1 and the CNBut nucleus giving
2
Ž .
Ž .
b-boron carrying the h -C H 5C H SiMe3 group, with
rise to a triplet resonance in the 13C H NMR spectrum
1
Ä1
4
this signal showing as expected no H–11 B coupling in
the fully coupled 11 B NMR spectrum. The chemical
shift is similar in magnitude to that for the correspond-
ing b-B nucleus in the related complex
w
Ž
.
x
at d 137.2 J NC s20 Hz .
The treatment of compound 4a with alkenes, alkynes
and transition metal alkylidynes has proven extremely
2
5
w
x
w
Ž
. Ž .x
Ž .
Ž .
fruitful 2,3 . Some reactions of complex 4b with transi-
Ru CO h ,h -10-C H 5C H SiMe3-7,8-C2 B9 H10
2
5b d 20.0 2 . The 11 B NMR spectra allow us to
w x
Ž
. Ž
. w x
tion metal alkylidynes have also been documented 3 ,
but to date we have not reported reactions of 4b with
simple alkenes and alkynes. A CH2Cl2 solution of
complex 4b, when treated with C7 H12 norbornene , did
not yield a stable ruthenium–alkene adduct. IR and
distinguish which boron atom in the coordinating face
of the cage may be involved in the non-innocent be-
haviour. Thus the corresponding signal for the com-
pound Ru CO h ,h -9-C H 5C H SiMe3-7,8-
C 2 B 9 H 1 0
Ž
.
2
5
w
Ž
x
. Ž
Ž
.
Ž .
2
.
Ž
.
mass spectral analysis revealed that the fragment
5c , w here an a-boron is
5
w
Ž
. Ž
.x
Ru CO h -7,8-Me2-7,8-C2 B9 H9 had been formed,
utilised in the
coordinating ring, occurs at d
2
w x
along with unidentified dark solid, which may be the
10.2 2 . Compound 5c is formed in the same reaction
as 5b, and is readily separated by column chromatogra-
phy. The employment of the b-boron in compound 5a
is further supported by previous observations that the
presence of methyl groups on the cage carbons in-
creases the propensity of the b-B–H bonds to become
5
w
Ž
. Ž
.x
polymeric Ru CO h -7,8-Me2-7,8-C2 B9 H9 n. To
2
our surprise, a similar result was obtained when CH2Cl2
solutions of 4b were treated with one or two equivalents
of MeC[CMe, PhC[CPh, or ButC[CH, respectively.
This is in stark contrast with the reactivity of complex
4a, which forms stable adducts with alkenes and alkynes.
w x
activated over the a-B–H bonds 9 . However, we
In the corresponding reactions of 4b, some
cannot rule out the formation of an a-isomer of com-
pound 5a, which may be present in the remainder of the
intractable mixture.
5
w
Ž
. Ž
.x
Ru CO h -7,8-Me2-7,8-C2 B9 H9 was detected in all
2
11
Ä1
4
cases. The B H NMR spectra of the residues from
the reactions were complex and indicated that nido-cage
systems were also present with peaks appearing at -d
y30, and other resonances in these spectra did not
3. Conclusion
show H–11 B coupling in fully coupled 11 B NMR
1
w
The formation of the salt 2a from Tl closo-1,2-Me2-
3
x
w
Ž
. Ž
.x
spectra. The treatment of complex 4b with a very large
excess of the alkenes or alkynes still produced in-
tractable mixtures and we have not been able to harness
these reactions. Thus, uncontrolled multiple hydrobora-
tions of the unsaturated hydrocarbon molecules may
have occurred, leading eventually to partial decomposi-
tion of the closo-3,1,2-RuC2 B9 cluster. It is, however,
possible to report a positive result with one particular
alkyne: reaction of a CH2Cl2 solution of 4b with
Me3SiC[CH gave a very complicated mixture. Never-
theless, after preparative thin layer chromatography
3,1,2-TlC2 B9 H9 and RuBr CO h -C3H5 was en-
3
tirely unexpected, and provides a novel example of a
bridging thallium centre. Despite the formation of 1b
and 2a as a mixture, this preparation was optimised to
produce a useful one-pot synthesis of complex 4b. The
Ž
reactions of 4b with simple donor molecules L Ls
PPh3, But NC, NC5H5 gave the expected products, but
.
the inability of compound 4b to react with alkynes and
alkenes to yield stable adducts is curious, particularly in
the light of successful reactions with tungsten– and
w x
molybdenum–alkylidyne complexes 3 . The latter reac-

(
)
34
J.C. Jeffery et al.rJournal of Organometallic Chemistry 551 1998 27–36
5
.
x
Ž
.
w
Ž
.Ž . Ž
4
tions may be driven to isolable complexes by virtue of
metal–metal bond formation. It seems, however, that 4b
is a reactive species and will yield further interesting
chemistry.
C2 B9 H9
1b and Tl Ru2 m-Tl CO h -7,8-Me2-
.
x
Ž
.
7,8-C B9 H
2a in a ratio of 2:3 respectively. The
salt NEt4 I 0.69 g, 2.68 mmol was then added, and
the reaction mixture was heated to reflux for a further 2
w 2
x 9 Ž2
.
h. The IR spectrum showed that 1b had reacted com-
5
w
xw
Ž
. Ž
pletely to give NEt4 RuI CO h -7,8-Me2-7,8-
2
.
x
Ž
.
4. Experimental section
C2 B9 H9 3b . The mixture was then cooled to 08C,
Ž
.
and I2 added in portions 0.27 g, 1.06 mmol until the
IR spectrum showed no more compound 2a was pre-
sent. The mixture was gradually warmed to room tem-
perature and the suspension was then filtered through
Solvents were distilled from appropriate drying agents
under nitrogen prior to use. Petroleum ether refers to
that fraction of boiling point 40–608C. All reactions
were carried out under an atmosphere of dry nitrogen
using Schlenk line techniques. Chromatography columns
Celite. Solvent was removed in vacuo, and the residue
3
Ž
.
was washed with diethyl ether 30 cm =3 and
3
Ž
.
Ž
.
ca. 15 cm in length and 2 cm in diameter were packed
petroleum ether 20 cm =3 to give 3b as a red solid
Ž
.
Ž
.
with silica gel Aldrich, 70–230 mesh or alumina
1.47 g . The product is sufficiently pure for subsequent
Ž
.
Aldrich, ca. 150 mesh . TLC was performed on prepar-
reactions. However, analytically pure 3b can be ob-
tained from a CH2Cl2 solution layered with petroleum
ether to give red crystals.
Ž
.
ative UNIPLATES silica gel G; Analtech . Celite pads
for filtration were ca. 3 cm thick. Chemicals were
purchased commercially from Aldrich Chemical or
5
[
(
)( ) (
2
4.3. Synthesis of Ru THF CO h -7,8-Me2-7,8-
w
x w x
Acros, except Tl closo-1,2-Me2-3,1,2-TlC2 B9 H9 10
3
)] (
)
C2 B9 H9
4b
w
Ž
. Ž
.x w x
and RuBr CO h -C3H5 11 , which were prepared
3
by the literature methods. The NMR spectra reported in
3
1
Ž
.
Ž
.
Compound 3b 0.08 g, 0.14 mmol in THF 10 cm
Table 3 were recorded at the following frequencies: H
at 360.13, 13C at 90.56, 31 P at 145.78 and 11 B at 115.5
MHz.
Ž
.
was treated with AgBF 0.03 g, 0.14 mmol . After 5
4
min, solvent was removed in vacuo. The residue was
3
Ž
.
treated with CH2Cl2 20 cm and the suspension fil-
5
tered through Celite. The resulting yellow solution of
[
][
(
)( ) (
4.1. Synthesis of NEt4 Ru2 m-Tl CO 4 h -7,8-Me2-
5
w
Ž
.Ž . Ž
.
x
Ž
.
Ru THF CO h -7,8-Me2-7,8-C2 B9 H9 4b can be
) ] (
)
2b
2
7,8-C2 B9 H9
2
used in situ. Because THF is lost when samples are
subjected to extended drying in vacuo, it was not possi-
ble to obtain suitable samples of 4b for microanalysis.
3
w
Ž
. Ž
.x Ž
A mixture of RuBr CO h -C3H5 1.00 g, 3.26
3
.
w
x Ž
mmol and Tl closo-1,2-Me2-3,1,2-TlC2 B9 H9 2.00 g,
3.51 mmol in THF 50 cm was heated to reflux for 4
h. The mixture was cooled to room temperature fol-
3
.
Ž
.
5
[
(
)( ) (
4.4. Synthesis of Ru NCMe CO 2 h -7,8-Me2-7,8-
)] (
)
C2 B9 H9
4c
w
x
Ž
.
lowed by the addition of NEt4 Cl 0.80 g, 4.8 mmol .
After stirring for another 1 h, the precipitate was filtered
off and the solvent of the red filtrate was removed in
Ž
.
A similar procedure using 3b 0.31 g, 0.54 mmol
3
Ž
.
Ž
.
and AgBF4 0.11 g, 0.55 mmol and MeCN 20 cm in
Ž
vacuo. The residue was dissolved in CH2Cl2 ca. 5
place of THF gave yellow microcrystals of
cm3 and chromatographed on alumina. The complex
5
.
Ž
w
Ž
.Ž . Ž
.
x
Ž
. Ž
Ru NCMe CO h -7,8-Me2-7,8-C2 B9 H9 4c 0.15
g
2
5
w
. Ž
.
x
Ž
.
Ru CO h -7,8-Me2-7,8-C2 B9 H9 1b was removed
first by eluting with CH2Cl2–petroleum ether 1:1 .
Further elution with neat CH2Cl2 removed a very broad
yellow fraction. Yellow microcrystals of NEt4 Ru2 m-
.Ž . Ž
Tl CO h -7,8-Me2-7,8-C2 B9 H9
3
.
after crystallisation from MeCN–petroleum ether
1:2, 10 cm at y208C.
Ž
.
3
Ž
.
5
w
xw
Ž
[
(
)( ) (
4.5. Synthesis of Ru PPh3 CO 2 h -7,8-Me2-7,8-
5
.
2 x
Ž
. Ž
.
2b 0.53 g were
)] (
)
C2 B9 H9
4d
4
obtained after the removal of the solvent in vacuo and
crystallisation from CH2Cl2-petroleum ether 1:2, 15
3
Ž
Ž
.
A yellow solution of 4b in CH2Cl2 20 cm was
3
.
Ž
.
cm .
generated from 3b 0.35 g, 0.61 mmol and AgBF
0.12 g, 0.62 mmol , as described above. To this, PPh3
0.17 g, 0.65 mmol was added and the mixture stirred
4
Ž
Ž
.
.
5
[
][
(
) (
4.2. One-pot synthesis of NEt4 RuI CO 2 h -7,8-Me2-
)] (
)
7,8-C2 B9 H9
3b
for 10 m. Solvent was reduced in volume in vacuo to
ca. 5 cm3 and the solution chromatographed on silica
3
w
Ž
. Ž
.x Ž
Ž
.
A mixture of RuBr CO h -C3H5 0.76 g, 2.48
gel. Elution with CH2Cl2–petroleum ether 1:1 re-
moved a yellow fraction. Solvent was then removed in
3
.
w
x Ž
mmol and Tl closo-1,2-Me2-3,1,2-TlC2 B9 H9 1.51 g,
2.65 mmol in THF 40 cm was heated to reflux for 4
h. The reaction was monitored by IR spectroscopy. At
3
.
Ž
.
vacuo to leave a yellow oil. Yellow microcrystals of
5
w
Ž
.Ž . Ž
.
x
Ž
. Ž
Ru PPh3 CO h -7,8-Me2-7,8-C2 B9 H9
4d 0.18
2
.
this stage, the IR spectrum showed that the reaction
g were formed upon crystallisation from CH2Cl2–pet-
roleum ether 3:7, 15 cm .
5
3
w
Ž
. Ž
Ž
.
mixture consisted mainly of Ru CO h -7,8-Me2-7,8-
3

(
)
J.C. Jeffery et al.rJournal of Organometallic Chemistry 551 1998 27–36
35
5
[
(
t)( ) (
4.6. Synthesis of Ru CNBu CO 2 h -7,8-Me2-7,8-
by preparative TLC with elution by CH2Cl2–petroleum
)] (
)
Ž
.
C2 B9 H9
4e
ether 1:4 . The top yellow band was collected, and
3
Ž
.
extracted with CH2Cl2 30 cm . Filtration and removal
of solvent in vacuo gave yellow microcrystals of
A similar procedure used a solution of 4b in CH2Cl2
3. Ž
2
5
Ž
Ž
.
20 cm generated from 3b 0.31 g, 0.54 mmol and
w
Ž
.
Ä
Ž .
Ž .
Ru CO h ,h -7,8-Me2-10-C H 5C H SiMe3-7,8-C2-
4
x
Ž2 . Ž
.
Ž
.
Ž
.
.
AgBF 0.11 g, 0.55 mmol , as described above which
was treated with Bu NC 67 mL, 0.64 mmol . Chro-
matography on silica gel, followed by crystallisation
B9 H8 5a 0.05 g .
4
t
4.9. X-ray structural analysis of 2b
3
Ž
.
from CH2Cl2–petroleum ether 1:4, 10 cm yielded
A suitable single-crystal of 2b for X-ray diffraction
was obtained from a THF solution layered with
petroleum ether. A low temperature data set for 2b was
collected with the crystal mounted on a glass fiber. Data
were collected on a Siemens SMART CCD area-detec-
tor 3-circle diffractometer using Mo K a X-radiation,
5
w
Ž
t.Ž . Ž
yellow microcrystals of Ru CNBu CO h -7,8-Me2-
2
.
x
Ž
. Ž
.
7,8-C2 B9 H9 4e 0.19 g .
5
[
(
)( ) (
4.7. Synthesis of Ru NC5 H5 CO 2 h -7,8-Me2-7,8-
)] ( )
4f
C2 B9 H9
˚
ls0.71073 A. Crystallographic parameters are listed
Using a similar procedure, a solution of 4b in CH2Cl2
3. Ž
in Table 4. For the three settings of f, narrow data
‘frames’ were collected for 0.38 increments in v. In all
cases, 1321 frames of data were collected affording
rather more than a hemisphere of data. The substantial
redundancy in data allows empirical absorption correc-
tions to be applied using multiple measurements of
equivalent reflections. Data frames were collected for
20 s per frame giving an overall data collection time of
ca. 10 h. The data frames were integrated using SAINT
Ž
Ž
.
20 cm generated from 3b 0.26 g, 0.45 mmol and
Ž
.
.
AgBF 0.09 g, 0.46 mmol , as described above when
4
3
Ž
.
treated with pyridine 1 cm , 12.4 mmol gave yellow
5
w
Ž
.Ž . Ž
microcrystals of Ru NC5H5 CO h -7,8-Me2-7,8-
2
.x Ž .
C2 B9 H9 4f .
2
5
[
(
) {
2
4.8. Synthesis of Ru CO h ,h -7,8-Me2-10-
( )
( )
}
] ( )
C H 5C H SiMe3-7,8-C2 B9 H8
5a
3
Ž
.
w
x
A yellow solution of 4b in THF 20 cm was
12 and the structure was solved by conventional direct
methods. The structure was refined by full-matrix
Ž
.
generated from 3b 0.33 g, 0.57 mmol and AgBF
4
least-squares on all F2 data using Siemens SHELXTL
Ž
.
0.12 g, 0.58 mmol . The solvent was removed in
vacuo, then CH2Cl2 15 cm added and the suspension
filtered through Celite. To the filtrate was added a
solution of Me3SiC[CH 82 mL, 0.58 mmol in
CH2Cl2 5 cm . The solution was stirred at room
temperature for 2 h. The solvent was removed in vacuo
and the yellow residue was extracted with CH2Cl2–pet-
roleum ether 1:1, 10 cm . The extract was then chro-
matographed on silica gel, eluting with CH2Cl2–petro-
leum ether 1:1 . A very broad yellow fraction was
collected, which IR and NMR spectroscopy showed to
be a complex mixture. Further purification was achieved
3
Ž
.
w
x
5.03 12 , and with anisotropic thermal parameters for
all non-hydrogen atoms. All hydrogen atoms were in-
cluded in calculated positions and allowed to ride on the
parent boron or carbon atoms with isotropic thermal
Ž
.
3
Ž
.
Ž
parameters Uiso s1.2=Uiso equivalent of the parent atom
.
except for Me protons where Uiso s1.3=Uiso equivalent
.
3
Ž
.
Ž .
The thallium atom Tl 1 lies on a two-fold axis of
w
xq
symmetry. The nitrogen atom N of the NEt4 cation
also sits on a two-fold axis of symmetry, with two ethyl
groups located and the remaining two generated by
symmetry. Both the ethyl groups located revealed de-
Ž
.
Table 4
Crystallographic data for 2b
Ž
.
Formula
Mol wt
C20 H50 B18 NO4Ru2Tl F 000
969.70
173
Orthorhombic
Pbcn
1872
Ž
.
Crystal dimensions mm
Crystal colour, shape
Reflections measured
Independent reflections
0.20=0.20=0.50
Yellow prism
16092
Ž .
T K
Crystal system
Space group
3246
˚
Ž .
a A
Ž .
23.164 2
Ž .
13.780 2
Ž .
11.560 6
Ž .
3690 2
Ž
.
2u range deg
4.9 to 50.0
Refinement method
Final residuals
Full-matrix least-squares on all F2 data
˚
Ž .
b A
wR2 s0.060a R1 s0.023
b
˚
Ž .
c A
Ž
.
3
V A
Weighting factors
as0.0292; bs8.2229a
˚
Ž
.
Z
4
Goodness-of-fit on F2
1.126
y3
y3
˚
Ž
.
Ž
. Ž
.
0.95, y0.75
Dcalc g cm
. Ž
1.746
.
5.194
Final electron density diff features maxrmin e A
y1
Ž
m Mo K a mm
aStructure was refined on Fo2 using all data: wR2 s Ý w Fo yFc
w w
rÝw Fo
2
1r2
2
2
Ž
2 .2 x
Ž
2 .2 x
w
2Ž
where wy1 s s Fo q aP qbP and Ps
.
Ž
.
x
2
2
w
Ž
.
x
max Fo ,0 q2Fc r3.
b The value in parentheses is given for comparison with refinements based on Fo with a typical threshold of Fo )4s Fo and R1 sÝ Fo y
<<
Ž
.
<
y1
2
<
<
<
<
<
w
2Ž
.
x
Fc rÝ Fo and w s s Fo qgFo .

(
)
36
J.C. Jeffery et al.rJournal of Organometallic Chemistry 551 1998 27–36
Table 5
4
2
3
˚
Ž
.
Ž
.
Atomic positional parameters fractional coordinates=10 and equivalent isotropic displacement parameters A =10 for the atoms of 2b
Atom
Ž .
x
y
z
Ua
eq
Ž .
Ž .
20 1
Tl 1
Ž .
5000
6017 1
6903 2
6673 1
6008 2
5799 2
6391 2
7027 2
7204 2
6643 2
6112 2
6350 2
6851 2
7341 2
6903 2
6177 2
6282 2
5690 2
5488 2
5000
4473 3
3818 5
4854 4
4760 5
3966 5
9213 1
8978 1
8275 3
8469 3
7960 3
7364 3
7630 3
7059 3
7610 4
7398 4
6697 3
6483 3
6482 4
8951 3
9324 3
10332 3
11135 2
9216 3
9314 3
6401 4
5829 4
6118 9
7444 6
7479 8
2500
1590 1
1562 3
2923 3
3149 3
1799 3
800 4
1365 4
2682 4
3664 4
2964 4
1520 4
2686 4
981 4
3627 4
1745 4
Ž .
Ž .
Ž .
Ž .
20 1
Ru 1
Ž .
Ž .
Ž .
Ž .
Ž .
26 1
C 1
Ž .
Ž .
Ž .
Ž .
Ž .
25 1
C 2
Ž .
Ž .
Ž .
Ž .
Ž .
24 1
B 3
Ž .
Ž .
Ž .
Ž .
Ž .
24 1
B 4
Ž .
Ž .
Ž .
Ž .
Ž .
26 1
B 5
Ž .
Ž .
Ž .
Ž .
Ž .
34 1
B 6
Ž .
Ž .
Ž .
Ž .
Ž .
35 1
B 7
Ž .
Ž .
Ž .
Ž .
Ž .
33 1
B 8
Ž .
B 10
Ž .
Ž .
Ž .
Ž .
31 1
B 9
Ž
.
.
.
.
Ž .
Ž .
Ž .
Ž .
32 1
Ž
Ž .
Ž .
Ž .
Ž .
38 1
B 11
Ž
Ž .
Ž .
Ž .
Ž .
37 1
C 10
Ž
Ž .
Ž .
Ž .
Ž .
39 1
C 20
Ž .
Ž .
Ž .
Ž .
Ž .
Ž .
40 1
C 3
Ž .
Ž .
Ž .
Ž .
73 1
O 3
1815 4
150 4
Ž .
Ž .
Ž .
Ž .
Ž .
34 1
C 4
Ž .
Ž .
Ž .
Ž .
Ž .
57 1
O 4
y755 3
Ž .
Ž .
88 3
N
y2500
Ž
.
.
.
Ž .
Ž .
Ž .
Ž .
63 2
C 31
y2536 5
Ž
Ž .
Ž .
Ž
.
.
Ž .
44 3
C 32
y2797 13
Ž
Ž .
Ž .
Ž .
Ž .
34 2
C 33
y2305 8
Ž .
y987 8
Ž
.
Ž .
Ž .
Ž .
52 3
C 34
X
Ž
.
.
.
Ž .
Ž
.
Ž
Ž .
Ž .
55 4
C 32
6434 10
6489 7
5497 8
y2388 14
X
Ž
Ž .
Ž .
Ž .
35 2
C 33
5061 3
5009 4
y937 7
Ž .
y295 9
X
Ž
Ž .
Ž .
Ž .
47 2
C 34
a Equivalent isotropic U defined as one-third of the trace of the orthogonalised Uij tensor.
grees of disorder. One ethyl group pivots about the
methylene carbon atom C 31 to give methyl positions
References
Ž
.
X
w x
1
S. Anderson, D.F. Mullica, E.L. Sappenfield, F.G.A. Stone,
Organometallics 14 1995 3516.
Ž
.
Ž
.
C 32 and C 32 , whose site occupations were each
fixed at 0.5 during refinement. The remaining ethyl
Ž
.
w x
2
S. Anderson, D.F. Mullica, E.L. Sappenfield, F.G.A. Stone,
Organometallics 15 1995 1676.
w
Ž
.
group showed disorder of its methylene C 33 and
Ž
.
X
X
Ž
.
x
w
Ž
.
Ž
.x
C 33 and its methyl C 34 and C 34 carbon atoms.
All four of these positions were refined with fixed site
occupancy factors of 0.5. Because of this severe disor-
der, protons were not assigned to these carbon atoms.
All calculations were carried out on Silicon Graphics
Iris, Indigo, or Indy computers. Final atomic positional
w x
3
S. Anderson, J.C. Jeffery, Y.-H. Liao, D.F. Mullica, E.L. Sap-
penfield, F.G.A. Stone, Organometallics 16 1997 958.
Ž
.
w x
4
Y.-H. Liao, D.F. Mullica, E.L. Sappenfield, F.G.A. Stone,
Organometallics 15 1996 5102.
Ž
.
w x
5
G.B. Ansell, M.A. Modrick, J.S. Bradley, Acta Crystallogr. C40
Ž
.
1984 1315.
w x
6
A.L. Balch, J.K. Nagle, M.M. Olmstead, P.E. Reedy Jr., J. Am.
Ž
.
Ž .
parameters x, y, z, U for non-hydrogen atoms are
Chem. Soc. 109 1987 4123.
eq
w x
Ž
.
7
w x
8
W.R. Hastings, M.C. Baird, Inorg. Chem. 25 1986 2913.
N. Masciocchi, M. Moret, P. Cairati, F. Ragaini, A. Sironi, J.
Chem. Soc., Dalton Trans., 1993 471.
listed in Table 5. Atomic coordinates, bond lengths and
angles, and thermal parameters have been deposited at
the Cambridge Crystallographic Data Centre.
Ž
.
w x
9
Ž
.
P.A. Jelliss, F.G.A. Stone, J. Organomet. Chem. 500 1995
307.
w
w
w
x
10 J.L. Spencer, M. Green, F.G.A. Stone, J. Chem. Soc., Chem.
Ž
.
Commun., 1972 1178.
Acknowledgements
x
11 G. Sbrana, G. Braca, F. Piacenti, P. Pino, J. Organomet. Chem.
Ž
.
13 1968 240.
We thank the Robert A. Welch Foundation for sup-
x
Ž
.
12 Siemens X-ray Instruments, Madison, WI, 1995 .
Ž
.
port Grant AA-1201 and Dr. Sihai Li for his initial
studies on the formation of 1b in our laboratory.