Carborane complexes of ruthenium: Synthesis and structural studies of Di- and triruthenium carbonyl species

Article abstract of DOI:10.1021/om9603629

The compounds [Ru₃(CO)¹²] and nido-7,8-Me₂-7,8-C₂B₉H₁₁ react in CH₂Cl₂ to yield a mixture of [Ru(CO)₃(η⁵-7,8-Me₂-7,8-C₂B ₉H₉)] (1b) and [Ru₃(CO)₈(η⁵-7,8-Me₂-7,8-C ₂B₉H₉)] (2) in a ratio of ca. 1:2. The tri- and dinuclear ruthenium complexes [Ru₃(μ-H)(μ-σ:η⁵-7,8-Me ₂-7,8-C₂B₉H₈)(CO) ₇(PR₃)] (PR₃ = PPh₃ (3), PCy₃ (6)), [Ru₃-(μ-H)(μ-σ:η⁵-7,8-Me ₂-7,8-C₂B₉H₈)(CO) ₆(PR₃)₂] (PR₃ = PPh₃ (4), PMe₂Ph (5)), [Ru₂(CO)₄(PMe₃)₂(η ⁵-7,8-Me₂-7,8-C₂B₉H₉)] (7), and [Ru₃(μ-dppm)(CO)₆(η⁵-7,8-Me ₂-7,8-C₂B₉H₉)] (8) have been prepared by treating 2 with tertiary phosphines. A single-crystal X-ray diffraction study on 5 revealed the structure as one in which a triangular array of ruthenium atoms is bridged by a nido-7,8-Me₂-7,8-C₂B₉H₈ group. The latter is pentahapto coordinated to one Ru atom, which carries two CO ligands, and is linked to the other metal atoms by a Ru-B and a B-H-Ru bond, respectively. These two ruthenium atoms are each coordinated by two CO groups and one PMe₂Ph group. Treatment of 2 with Me₂NCH₂NMe₂ in CH₂Cl₂ affords a mixture of the complexes [Ru₂ (μ-η⁵-7,8-Me₂10-CH₂NMe ₂-7,8-C₂B₉H₈)(CO)₅] (9) and [Ru₂(CO)₅(NHMe₂)(η⁵-7,8-Me ₂-7,8-C₂B₉H₉)] (10). The structures of both diruthenium compounds were established by X-ray diffraction. In 9 the Ru-Ru bond is bridged by the 7,8-Me₂-10-CH₂NMe₂-7,8-C₂B ₉H₈ cage system. The open pentagonal CCBBB face is coordinated to one Ru atom, which also carries two CO molecules, while the exopolyhedral CH₂NMe₂ group is coordinated to the other Ru atom which is also ligated by three CO molecules. In 10 a Ru(CO)₂(η⁵-7,8-Me₂-7,8-C₂B ₉H₉) moiety with a closo3,1,2-RuC₂B₉ framework is linked by exopolyhedral Ru-Ru and B-H-?Ru bonds to a Ru(CO)₃(NHMe₂) group. The reaction between 2 and pyridine affords a mixture of [Ru₂(CO)₅(NC₅H₅)(η ⁵-7,8-Me₂-7,8-C₂B₉H₉)] (11) and [Ru₂(CO)₄(NC₅H₅) ₂(η⁵-7,8-Me₂-7,8-C₂B ₉H₉)] (12). An X-ray diffraction study on 11 revealed a molecular structure similar to that of 10. The new compounds have been characterized by NMR spectroscopy in addition to the X-ray diffraction studies.

Full text of DOI:10.1021/om9603629

5102
Organometallics 1996, 15, 5102-5111
Ca r bor a n e Com p lexes of Ru th en iu m : Syn th esis a n d
Str u ctu r a l Stu d ies of Di- a n d Tr ir u th en iu m Ca r bon yl
Sp ecies†
Yi-Hsien Liao, Donald F. Mullica, Eric L. Sappenfield, and F. Gordon A. Stone*
Department of Chemistry, Baylor University, Waco, Texas 76798-7348
Received May 14, 1996X
The compounds [Ru3(CO)12] and nido-7,8-Me2-7,8-C2B9H11 react in CH2Cl2 to yield a mixture
of [Ru(CO)3(η5-7,8-Me2-7,8-C2B9H9)] (1b) and [Ru3(CO)8(η5-7,8-Me2-7,8-C2B9H9)] (2) in a ratio
of ca. 1:2. The tri- and dinuclear ruthenium complexes [Ru3(µ-H)(µ-σ:η5-7,8-Me2-7,8-C2B9H8)-
(CO)7(PR3)] (PR3 ) PPh3 (3), PCy3 (6)), [Ru3(µ-H)(µ-σ:η5-7,8-Me2-7,8-C2B9H8)(CO)6(PR3)2] (PR3
) PPh3 (4), PMe2Ph (5)), [Ru2(CO)4(PMe3)2(η5-7,8-Me2-7,8-C2B9H9)] (7), and [Ru3(µ-dppm)-
(CO)6(η5-7,8-Me2-7,8-C2B9H9)] (8) have been prepared by treating 2 with tertiary phosphines.
A single-crystal X-ray diffraction study on 5 revealed the structure as one in which a
triangular array of ruthenium atoms is bridged by a nido-7,8-Me2-7,8-C2B9H8 group. The
latter is pentahapto coordinated to one Ru atom, which carries two CO ligands, and is linked
to the other metal atoms by a Ru-B and a B-HFRu bond, respectively. These two
ruthenium atoms are each coordinated by two CO groups and one PMe2Ph group. Treatment
of 2 with Me2NCH2NMe2 in CH2Cl2 affords a mixture of the complexes [Ru2(µ-η5-7,8-Me2-
10-CH2NMe2-7,8-C2B9H8)(CO)5] (9) and [Ru2(CO)5(NHMe2)(η5-7,8-Me2-7,8-C2B9H9)] (10). The
structures of both diruthenium compounds were established by X-ray diffraction. In 9 the
Ru-Ru bond is bridged by the 7,8-Me2-10-CH2NMe2-7,8-C2B9H8 cage system. The open
pentagonal CCBBB face is coordinated to one Ru atom, which also carries two CO molecules,
while the exopolyhedral CH2NMe2 group is coordinated to the other Ru atom which is also
ligated by three CO molecules. In 10 a Ru(CO)2(η5-7,8-Me2-7,8-C2B9H9) moiety with a closo-
3,1,2-RuC2B9 framework is linked by exopolyhedral Ru-Ru and B-HFRu bonds to a Ru-
(CO)3(NHMe2) group. The reaction between 2 and pyridine affords a mixture of [Ru2(CO)5-
(NC5H5)(η5-7,8-Me2-7,8-C2B9H9)] (11) and [Ru2(CO)4(NC5H5)2(η5-7,8-Me2-7,8-C2B9H9)] (12).
An X-ray diffraction study on 11 revealed a molecular structure similar to that of 10. The
new compounds have been characterized by NMR spectroscopy in addition to the X-ray
diffraction studies.
In tr od u ction
methyl substituents rather than hydrogen is intriguing
although the reason for this remains unresolved. How-
ever, the nature of metallacarborane complexes pro-
duced in syntheses is known to be much influenced by
the presence or absence of substituents on the carbon
vertices of the precursor.2 Evidently the formation of
2 and the nonformation of [Ru3(CO)8(η5-7,8-C2B9H11)]
in the previous work1 is a further manifestation of this
behavior.
We reported recently that the mononuclear ruthe-
nium complex [Ru(CO)3(η5-7,8-C2B9H11)] (1a ) (Chart 1)
can be readily prepared by heating [Ru3(CO)12] with
nido-7,8-C2B9H13 in heptane at reflux temperatures.1 No
polynuclear ruthenium species were isolated from this
reaction. In contrast, as described in this paper, the
corresponding reaction between [Ru3(CO)12] and nido-
7,8-Me2-7,8-C2B9H11 affords a mixture of the mono- and
trinuclear ruthenium complexes [Ru(CO)3(η5-7,8-Me2-
7,8-C2B9H9)] (1b) and [Ru3(CO)8(η5-7,8-Me2-7,8-C2B9H9)]
(2), with the latter as the predominant product. The
favored formation of the triruthenium species when the
carbon vertices in the nido-carborane precursor carry
As far as we are aware, the cluster compound 2 and
the compounds [NEt4][Mo3(µ3-CC6H4Me-4)(µ-CO)(CO)8-
(η5-7,8-C2B9H11)]3 and [Ru3(CO)8(η5-7-NR3-7-CB10H10)]4
are the only known homonuclear trimetal species of the
transition elements having a carborane ligand attached
to the metal triangle, although several heteronuclear
trimetal compounds with these ligands have been
characterized.2 Compound 2 has a potentially interest-
ing derivative chemistry, hence in addition to its
synthesis we describe herein reactions with several
donor molecules.
* To whom correspondence should be addressed.
† In the compounds described in this paper ruthenium atoms and
nido-C2B9 cages form closo-1,2-dicarba-3-ruthenadodecaborane struc-
tures. However, use of this numbering scheme leads to a complicated
nomenclature for the polynuclear metal complexes reported. Following
precedent (Mullica, D. F.; Sappenfield, E. L.; Stone, F. G. A.; Woollam,
S. F. Organometallics 1994, 13, 157) therefore we treat the cage as a
nido 11-vertex ligand with numbering as for an icosahedron from which
the twelfth vertex has been removed. This has the added convenience
of relating the metallacarborane complexes to isolobal species with η5-
C5H5 ligands.
(2) (a) Stone, F. G. A. Adv. Organomet. Chem. 1990, 31, 135. (b)
Brew, S. A.; Stone, F. G. A. Adv. Organomet. Chem. 1993, 35, 135. (c)
J elliss, P. A.; Stone, F. G. A. J . Organomet. Chem. 1995, 500, 307.
(3) Dossett, S. J .; Hart, I. J .; Stone, F. G. A. J . Chem. Soc., Dalton
Trans. 1990, 3489.
(4) Lebedev, V. N.; Mullica, D. F.; Sappenfield, E. L.; Stone, F. G.
A. Organometallics 1996, 15, 1669.
X Abstract published in Advance ACS Abstracts, November 1, 1996.
(1) Anderson, S.; Mullica, D. F.; Sappenfield, E. L.; Stone, F. G. A.
Organometallics 1995, 14, 3516.
S0276-7333(96)00362-7 CCC: $12.00 © 1996 American Chemical Society

Carborane Complexes of Ruthenium
Organometallics, Vol. 15, No. 24, 1996 5103
Ta ble 1. An a lytica l a n d P h ysica l Da ta
anal./%b
compd
color
yield/%
ν
max(CO)a/cm-1
C
H
[Ru(CO)3(η5-7,8-Me2-7,8-C2B9H9)] (1b)
pale yellow
orange-red
red
20
40
54
76
74
55
66
29
4
2110 s, 2054 s
24.4 (24.3)
4.4 (4.4)
[Ru3(CO)8(η5-7,8-Me2-7,8-C2B9H9)] (2)
2096 s, 2060 s, 2026 s, 2000 m, 1960 w
2074 s, 2050 s, 2014 s, 1994 s, 1932 w
23.8 (24.1)c 2.8 (2.9)
[Ru3(µ-H)(µ-σ:η5-7,8-Me2-7,8-C2B9H8)(CO)7(PPh3)] (3)
[Ru3(µ-H)(µ-σ:η5-7,8-Me2-7,8-C2B9H8)(CO)6(PPh3)2] (4)
38.1 (37.8)
3.5 (3.3)
red
2054 s, 2014 s, 1996 w, 1974 m, 1948 m 45.8 (45.5)d 3.6 (3.8)
[Ru3(µ-H)(µ-σ:η5-7,8-Me2-7,8-C2B9H8)(CO)6(PMe2Ph)2] (5) red
2048 s, 2010 s, 1988 w, 1968 m, 1944 m 33.8 (34.4)
4.1 (4.1)
[Ru3(µ-H)(µ-σ:η5-7,8-Me2-7,8-C2B9H8)(CO)7(PCy3)] (6)
[Ru2(CO)4(PMe3)2(η5-7,8-Me2-7,8-C2B9H9)] (7)
[Ru3(µ-dppm)(CO)6(η5-7,8-Me2-7,8-C2B9H9)] (8)
[Ru2(µ-η5-7,8-Me2-10-CH2NMe2-7,8-C2B9H8)(CO)5] (9)
[Ru2(CO)5(NHMe2)(η5-7,8-Me2-7,8-C2B9H9)] (10)
[Ru2(CO)5(NC5H5)(η5-7,8-Me2-7,8-C2B9H9)] (11)
[Ru2(CO)4(NC5H5)2(η5-7,8-Me2-7,8-C2B9H9)] (12)
red
orange-red
red
orange-red
orange-red
orange-red
orange-red
2070 m, 2040 s, 2008 sh, 1990 s, 1932 w 38.7 (39.1)c 6.0 (5.6)
1988 s, 1954 s, 1898 m
26.9 (26.8)
5.5 (5.3)
2032 s, 1994 s, 1976 sh, 1938 w
2084 s, 2018 s, 1984 m, 1942 m
2096 s, 2028 s, 1976 s, 1928 s
2094 s, 2030 s, 1972 m, 1926 m
2038 s, 1976 s, 1970 sh, 1906 s
45.1 (44.2)e 4.4 (4.5)
25.5 (25.8)f 3.9 (4.0)
23.6 (24.1)g 3.9 (4.1)
28.0 (28.9)h 3.4 (3.5)
32.5 (31.8)d,i 3.7 (3.8)
22
8
26
a
Measured in CH2Cl2. A medium-intensity broad band observed at ca. 2550 cm-1 in the spectra of all the compounds is due to B-H
absorptions. Calculated values are given in parentheses. c Crystallizes with 0.5 molecule of n-pentane. Crystallizes with 1 molecule of
b
d
CH2Cl2. e Crystallizes with 1 molecule of n-pentane. f N 2.4 (2.5). N 2.4 (2.6). N 2.4 (2.4). N 4.2 (3.9).
g
h
i
Ch a r t 1
and the other employs the unique boron atom in the
CCBBB ring which has no connectivity with the car-
bons. In accord with this asymmetry, the nonequivalent
CMe groups give rise to two signals (δ 2.22 and 2.47) in
the 1H NMR spectrum and four resonances (δ 62.5, 74.3
(CMe); δ 30.2, 32.5 (CMe)) in the 13C{1H} spectrum
(Table 2).
In the 1H NMR spectrum the nonequivalent B-HFRu
groups give rise to only one quartet (δ -10.23) in the
chemical shift range diagnostic for a B-HFRu three-
center two-electron bond.2b This quartet is very broad,
however, and since its relative intensity corresponds to
two protons it must result from overlapping of two sets
of peaks. In contrast, the 11B{1H} spectrum shows two
resonances (δ 15.8 and 24.4) attributable to the non-
equivalent B-HFRu groups (Table 3). Diagnostically
for these groups, in the fully coupled 11B NMR spectrum
these signals became doublets with 1H-11B couplings
of 76 and 62 Hz, respectively, as compared with values
of ca. 120-140 Hz observed for the doublet resonances
for the terminal B-H groups.2b The 13C{1H} NMR
spectrum of 2 shows seven resonances for the eight CO
groups, but one peak has an intensity corresponding to
two carbonyl ligands (Table 2). This pattern is in
agreement with the overall asymmetry. The mode of
bonding of the nido-7,8-Me2-7,8-C2B9H9 group to the
metal triangle in 2 with pentahapto coordination to one
metal atom producing a closo-3,1,2-RuC2B9 framework
and concomitant formation of two exopolyhedral
B-HFRu bonds to the other metal centers is very
common and has been established by X-ray diffraction
in several heteronuclear trimetal complexes.2 Moreover,
the monocarbon-carborane triruthenium zwitterionic
complex [Ru3(CO)8(η5-7-NMe3-7-CB10H10)] similarly has
two B-HFRu bridge bonds.4
Reactions of 2 with various donor ligands were
investigated. Treatment of 2 with PPh3 in THF at room
temperature gave [Ru3(µ-H)(µ-σ:η5-7,8-Me2-7,8-C2B9H8)-
(CO)7(PPh3)] (3), whereas when the reaction was carried
out in the same solvent at reflux temperature the bis-
(phosphine) complex [Ru3(µ-H)(µ-σ:η5-7,8-Me2-7,8-C2-
B9H8)(CO)6(PPh3)2] (4) was formed. A similar bis(pho-
sphine) complex [Ru3(µ-H)(µ-σ:η5-7,8-Me2-7,8-C2B9H8)-
(CO)6(PMe2Ph)2] (5) was obtained by treating 2 with
excess of PMe2Ph in CH2Cl2 at room temperature. Data
characterizing complexes 3-5 are given in Tables 1-3.
All three molecules have a similar framework structure
which was established for 5 by an X-ray diffraction
Resu lts a n d Discu ssion
The mono- and trinuclear ruthenium complexes 1b
and 2 are readily formed in a ratio of ca. 1:2 by heating
[Ru3(CO)12] with nido-7,8-Me2-7,8-C2B9H11 in CH2Cl2.
The compounds are separable by column chromatogra-
phy on silica gel and were characterized by the data
listed in Tables 1-3. The microanalytical and spectro-
scopic data for 1b are in accord with its formulation as
an analog of 1a with the cage carbons carrying Me
substituents. For 2 the 1H, 11B{1H}, and 11B NMR data
are in agreement with it being a triruthenium complex.
One ruthenium center is pentahapto coordinated by the
nido-7,8-Me2-7,8-C2B9H9 fragment which forms two
exopolyhedral B-HFRu bonds to the other two ruthe-
nium atoms. The structure is asymmetric since one
B-HFRu linkage employs a boron atom adjacent to
carbon in the open CCBBB ring ligating the Ru atom,

5104 Organometallics, Vol. 15, No. 24, 1996
Ta ble 2. Hyd r ogen -1 a n d Ca r bon -13 NMR Da ta a
Liao et al.
compd
δ(1H)b
δ(13C)c
1b 2.30 (s, 6H, Me)
189.6 (CO), 78.7 (CMe), 32.9 (CMe)
2
3
4
5
-10.23 (q vbr, 2 H, B-HFRu), 2.22, 2.47 (s × 2, 6 H, CMe)
200.1, 199.8, 198.3, 195.5, 190.2, 189.8 (CO), 185.4 (CO × 2), 74.3, 62.5
(CMe), 32.5, 30.2 (CMe)
201.7, 198.8, 198.5, 196.2, 195.2, 194.0, 192.1 (CO),
134.1-128.8 (Ph), 73.2, 62.1 (CMe), 33.3, 32.5 (CMe)
203.5, 202.1, 201.9, 200.2 (CO), 199.9 (CO × 2), 136.1-128.1 (Ph), 65.9,
62.8 (CMe), 33.3, 32.7 (CMe)
203.6, 201.3 (CO), 200.4 (CO × 2), 198.1, 193.1 (CO), 142.1-128.1 (Ph),
74.1, 62.6 (CMe), 33.6, 32.7 (CMe), 22.6 (d, MeP × 2, J (PC) ) 34),
22.5, 22.1 (d × 2, MeP, J (PC) ) 34, 35)
-17.51 (s br, 1 H, Ru(µ-H)Ru), -9.30 (m vbr, 1 H, B-HFRu),
2.36, 2.48 (s × 2, 6 H, CMe), 7.40-7.60 (m, 15 H, Ph)
-16.22 (s br, 1 H, Ru(µ-H)Ru), -9.40 (m vbr, 1 H, B-HFRu),
2.35, 2.51 (s × 2, 6 H, CMe), 7.00-7.40 (m, 30 H, Ph)
-16.99 (s br, 1 H, Ru(µ-H)Ru), -10.08 (q br, 1 H, B-HFRu,
J (BH) ) 70), 1.57 (d, 3 H, MeP, J (PH) ) 10), 1.88 (d, 6 H, MeP,
J (PH) ) 10), 1.94 (d, 3 H, MeP, J (PH) ) 10), 2.39, 2.49 (s × 2, 6
H, CMe), 7.20-7.70 (m, 10 H, Ph)
-18.37 (s br, 1 H, Ru(µ-H)Ru), -10.10 (q br, 1 H, B-HFRu,
J (BH) ) 73), 1.29-1.88 (m, 33 H, C6H11), 2.38, 2.49 (s × 2, 6 H,
CMe)
-11.02 (d of q, 1 H, B-HFRu, J (BH) ) 78, J (PH) ) 31), 1.67,
1.73 (d × 2, 18 H, MeP, J (PH) ) 10, 10), 2.37 (s, 6 H, CMe)
-9.11 (q br, 2 H, B-HFRu, J (BH) ) 80), 2.17, 2.47 (s × 2, 6 H,
CMe), 4.62, 4.86 (d of d of d × 2, 2 H, CH2, J (HH) ) 14, J (PH) )
11, 11), 7.10-7.50 (m, 20 H, Ph)
6
202.0, 201.4, 200.2, 199.6, 198.9, 197.2, 195.4 (CO), 73.2, 61.7 (CMe),
39.1 (d, C6H11, J (PC) ) 22), 33.4, 32.6 (CMe), 29.7 (d, C6H11, J (PC)
) 24), 27.6 (d, C6H11, J (PC) ) 11), 26.2 (C6H11
)
7
8
206.2 (CO × 2), 204.3 (d of d, CO × 2, J (PC) ) 16, 9), 63.2 (CMe),
32.0 (CMe), 23.0 (d, MeP, J (PC) ) 34)
200.8, 198.4 (CO), 196.4, 192.4 (CO × 2), 138.9-128.5 (Ph), 73.2, 60.0
(CMe), 58.8 (d of d, CH2, J (PC) ) 26), 32.8, 29.8 (CMe)
9
-6.91 (q br, 1 H, B-HFRu, J (BH) ) 77), 2.22, 2.30 (s × 2, 6 H,
CMe), 2.31, 2.42 (s br × 2, 2 H, BCH2N), 2.73, 2.83 (s × 2, 6 H,
Me2N)
204.0 (br, CO × 3), 200.5, 197.8 (CO), 66.9 (vbr, CMe), 65.2 (CH2N),
63.6, 62.9 (Me2N), 33.0, 30.2 (CMe)
10
-8.19 (q br, 1 H, B-HFRu, J (BH) ) 76), 2.35, 2.37 (s × 2, 6 H,
CMe), 2.43, 2.78 (d × 2, 6 H, Me2N, J (HH) ) 6), 3.68 (s br, 1 H,
NH)
200.7, 200.2 (CO), 65.1 (vbr, CMe), 50.2, 48.7 (Me2N), 31.9, 31.8 (CMe)
11
12
-7.82 (q br, 1 H, B-HFRu, J (BH) ) 80), 2.13, 2.33 (s × 2, 6 H,
201.7, 200.6 (CO), 154.9, 138.9, 126.3 (py), 65.2, 64.7 (CMe), 31.8
CMe), 7.30-8.30 (m, 5 H, py)
(br, CMe)
-5.28 (q br, 1 H, B-HFRu, J (BH) ) 67), 2.15, 2.35 (s × 2, 6 H,
CMe), 7.20-8.50 (m, 10 H, py)
203.6, 202.5, 201.1, 200.5 (CO), 155.0-125.8 (py), 63.9 (br, CMe), 31.8
(br, CMe)
a
b
Chemical shifts (δ) in ppm, coupling constants (J ) in Hz, measurements at ambient temperatures in CD2Cl2. Resonances for terminal
BH protons occur as broad unresolved signals in the range δ ca. -2 to 3. c Hydrogen-1 decoupled; chemical shifts are positive to high
frequency of SiMe4.
Ta ble 3. Bor on -11 a n d P h osp h or u s-31 NMR Da ta a
compd
δ(11B)b,c
δ(31P)d
1b
2
9.1 (1 B), -3.6 (2 B), -4.9 (3 B), -8.0 (1 B), -11.1 (2 B)
24.4 (1 B, B-HFRu, J (HB) ) 62), 15.8 (1 B, B-HFRu, J (HB) ) 76), -3.4 (1 B), -5.1 (3 B), -8.6 (2 B),
-10.9 (1 B)
3
4
5
6
7
8
43.0 (1 B, Ru-B), 32.1 (1 B, B-HFRu, J (HB) ) 72), -4.6 (3 B), -5.5 (1 B), -7.4 (1 B), -9.3 (2 B)
44.5 (vbr, 1 B, Ru-B), 32.4 (1 B, B-HFRu, J (HB) ) 57), -5.0 (4 B), -9.3 (3 B)
42.1 (1 B, Ru-B), 32.3 (1 B, B-HFRu, J (HB) ) 70), -5.7 (2 B), -6.5 (2 B), -9.5 (3 B)
43.1 (1 B, Ru-B), 32.4 (1 B, B-HFRu, J (HB) ) 73), -4.8 (3 B), -7.7 (1 B), -9.8 (2 B), -13.1 (1 B)
18.3 (1 B, B-HFRu, J (HB) ) 78), -8.5 (2 B), -9.9 (2 B), -11.7 (3 B), -18.0 (1 B)
23.0 (1 B, B-HFRu, J (HB) ) 80), 15.6 (1 B, B-HFRu, J (HB) ) 70), -5.0 (2 B), -6.5 (2 B), -10.2 (2 B),
-12.4 (1 B)
24.9 (1 B B-HFRu, J (HB) ) 77), -1.6 (1 B), -4.3 (1 B), -5.6 (3 B), -8.2 (1 B), -16.6 (1 B), -19.7 (1 B)
26.6 (1 B, B-HFRu, J (HB) ) 76), -6.5 (1 B), -7.5 (1 B), -9.3 (1 B), -10.1 (1 B), -11.1 (2 B), -12.2 (1 B),
-17.4 (1 B)
42.0 (s)
43.3 (s), 53.9 (br s)
9.2 (s), 18.2 (s)
67.6 (s)
-11.4 (s), -0.1 (s)
24.7, 21.1 (d × 2, J (PP) ) 25)
9
10
11
12
27.7 (1 B, B-HFRu, J (HB) ) 80), -6.8 (1 B), -7.7 (1 B), -9.7 (2 B), -11.3 (3 B), -17.7 (1 B)
20.4 (1 B, B-HFRu, J (HB) ) 67), -9.1 (2 B), -11.4 (5 B), -17.4 (1 B)
a
b
Measurements at ambient temperatures in CD2Cl2. Hydrogen-1 decoupled; chemical shifts (δ) in ppm are positive to high frequency
of BF3‚Et2O (external). Signals ascribed to more than one boron nucleus may result from overlapping peaks and do not necessarily
indicate symmetry equivalence. c The 1H-11B coupling constants (Hz) were measured from fully coupled 11B spectra. Hydrogen-1
decoupled; chemical shifts (δ) in ppm are positive to high frequency of H3PO4 (external).
d
study. The molecule is shown in Figure 1, and selected
bond distances and angles are listed in Table 4.
The Ru atoms form a triangular array [Ru(1)-Ru(2)
) 2.750(1), Ru(1)-Ru(3) ) 2.812(1), Ru(2)-Ru(3) )
2.972(1) Å], with Ru(1) ligated by the nido-7,8-C2B9 cage
in the usual pentahapto mode. The cage bridges the
metal triangle via a boron-ruthenium σ-bond and an
agostic B-HFRu interaction. The exopolyhedral B-Ru
σ-bond distance [B(5)-Ru(3) ) 2.15(1) Å] is the same
as that found in [Ru3(µ-H)(µ-σ:η5-7-NMe3-7-CB10H9)-
(CO)7(PPh3)] which has a very similar structure.4 The
B-HFRu bond in 5 involves the B(4)H(4) group and
Ru(2). Although H(4) was not directly located from the
difference Fourier mapping, its presence was clearly
revealed by the NMR data, discussed below. The
separations B(4)-Ru(2) [2.34(1) Å], B(4)-H(4) (ca. 1.12
Å), and Ru(2)-H(4) (ca. 1.77 Å) compare well with the
corresponding parameters for the B-HFRu group in
[Ru3(µ-H)(µ-σ:η5-7-NMe3-7-CB10H9)(CO)7(PPh3)] of 2.37(1),
1.08, and 1.76 Å, respectively.
F igu r e 1. Molecular structure of [Ru3(µ-H)(µ-σ:η5-7,8-Me2-
7,8-C2B9H8)(CO)6(PMe2Ph)2] (5), showing the crystallo-
graphic labeling scheme. Except for H(1) and H(4), hydro-
gen atoms have been omitted for clarity, and thermal
ellipsoids are shown at 50% probability level.

Carborane Complexes of Ruthenium
Organometallics, Vol. 15, No. 24, 1996 5105
Ta ble 4. Selected In ter n u clea r Dista n ces (Å) a n d An gles (d eg) for
[Ru 3(µ-σ:η5-7,8-Me2-7,8-C2B9H8)(CO)6(P Me2P h )2] (5), w ith Estim a ted Sta n d a r d Devia tion s in P a r en th eses
Ru(1)-C(1)
Ru(1)-B(5)
Ru(1)-Ru(3)
C(1)-B(5)
2.26(1)
2.22(1)
2.812(1)
1.82(2)
1.71(2)
1.76(2)
1.82(2)
1.77
1.73(3)
1.82(2)
1.80(3)
2.972(1)
1.17(1)
1.81(1)
1.17(2)
1.79(1)
Ru(1)-C(2)
Ru(1)-C(5)
H(1)-Ru(2)
C(1)-B(6)
C(2)-B(6)
B(3)-B(7)
B(4)-B(8)
B(5)-B(9)
B(6)-B(10)
B(8)-B(9)
B(10)-B(11)
Ru(2)-C(7)
C(8)-O(8)
Ru(3)-C(17)
C(18)-O(18)
2.31(1)
1.88(1)
1.78
Ru(1)-B(3)
Ru(1)-C(6)
H(1)-Ru(3)
C(1)-B(10)
C(2)-B(7)
B(3)-B(8)
B(4)-B(9)
B(5)-B(10)
B(6)-B(11)
B(8)-B(11)
C(5)-O(5)
Ru(2)-C(8)
P(1)-C(9)
2.24(2)
1.82(1)
1.78
Ru(1)-B(4)
Ru(1)-Ru(2)
C(1)-C(2)
C(1)-C(3)
C(2)-C(4)
B(4)-H(4)
B(4)-Ru(2)
B(5)-Ru(3)
B(7)-B(*)
B(9)-B(10)
C(6)-O(6)
Ru(2)-P(1)
P(1)-C(10)
Ru(3)-P(2)
P(2)-C(20)
2.22(1)
2.750(1)
1.65(2)
1.57(2)
1.46(2)
1.12
2.34(1)
2.15(1)
1.80(2)
1.77(2)
1.19(2)
2.331(3)
1.79(1)
2.285(3)
1.77(1)
1.75(3)
1.75(3)
1.76(2)
1.76(2)
1.76(2)
1.76(3)
1.82(2)
1.77(3)
1.83(1)
1.17(2)
1.82(1)
1.17(2)
1.76(2)
1.70(2)
1.77(2)
1.79(2)
1.83(2)
1.73(3)
1.83(2)
1.20(2)
1.87(1)
1.82(1)
1.90(1)
1.79(1)
C(2)-B(3)
B(3)-B(4)
B(4)-B(5)
H(4)-Ru(2)
B(6)-B(7)
B(7)-B(11)
B(9)-B(11)
Ru(2)-Ru(3)
C(7)-O(7)
P(1)-C(11)
C(17)-O(17)
P(2)-C(21)
Ru(3)-C(18)
P(2)-C(19)
C(5)-Ru(1)-C(6)
C(6)-Ru(1)-Ru(3)
Ru(2)-H(1)-Ru(3)
Ru(1)-C(5)-O(5)
Ru(1)-Ru(2)-H(4)
H(4)-Ru(2)-C(7)
Ru(1)-Ru(2)-P(1)
C(8)-Ru(2)-P(1)
C(7)-Ru(2)-Ru(3)
Ru(2)-C(8)-O(8)
Ru(1)-Ru(3)-Ru(2)
83.6(6)
132.5(5)
113.2(1)
C(5)-Ru(1)-Ru(2)
B(4)-Ru(1)-Ru(2)
Ru(1)-B(4)-H(4)
106.1(4)
54.8(3)
120.8(9)
C(5)-Ru(1)-Ru(3)
B(5)-Ru(1)-Ru(3)
B(4)-H(4)-Ru(2)
69.4(4) C(6)-Ru(1)-Ru(2)
48.8(4) Ru(2)-Ru(1)-Ru(3)
105.7(7) Ru(1)-B(5)-Ru(3)
92.0(5) Ru(1)-Ru(2)-H(1)
94.7(4) H(1)-Ru(2)-C(7)
174.3(4) H(4)-Ru(2)-C(8)
93.7(1) C(7)-Ru(2)-P(1)
33.4(1) H(4)-Ru(2)-Ru(3)
118.1(1) Ru(2)-C(7)-O(7)
114.7(5) Ru(2)-P(1)-C(11)
88.1(5)
64.6(1)
80.2(5)
90.4(1)
92.4(4)
90.6(4)
92.9(4)
89.6(1)
177.4(11)
118.5(4)
174.2 (12) Ru(1)-C(6)-O(6)
176.3(14) C(7)-Ru(2)-C(8)
78.5(1)
172.8(4)
171.4(1)
90.9(4)
84.9(4)
178.5(11)
56.7(1)
H(1)-Ru(2)-H(4)
Ru(1)-Ru(2)-C(8)
H(1)-Ru(2)-P(1)
Ru(1)-Ru(2)-Ru(3)
C(8)-Ru(2)-Ru(3)
Ru(2)-P(1)-C(9)
Ru(1)-Ru(3)-H(1)
Ru(1)-Ru(3)-P(2)
Ru(2)-Ru(3)-P(2)
H(1)-Ru(3)-C(18)
B(5)-Ru(3)-P(2)
85.5(1)
92.8(4)
85.3(1)
58.7(1)
150.8(4)
112.7(5)
88.3(1)
143.5(1)
113.6(1)
88.7(4)
93.3(4)
Ru(1)-Ru(2)-C(7)
H(1)-Ru(2)-C(8)
H(4)-Ru(2)-P(1)
H(1)-Ru(2)-Ru(3)
P(1)-Ru(2)-Ru(3)
Ru(2)-P(1)-C(10)
Ru(1)-Ru(3)-B(5)
Ru(2)-Ru(3)-B(5)
C(17)-Ru(3)-C(18)
H(1)-Ru(3)-P(2)
C(17)-Ru(3)-P(2)
51.0(4) Ru(1)-Ru(3)-C(17) 104.7(4)
76.1(4) Ru(2)-Ru(3)-C(17) 160.8(4)
Ru(1)-Ru(3)-C(18) 116.5(4)
Ru(2)-Ru(3)-C(18)
H(1)-Ru(3)-C(17)
B(5)-Ru(3)-C(18)
Ru(3)-C(17)-O(17) 176.7(11)
Ru(3)-P(2)-C(21)
94.0(4)
165.8(4)
167.0(5)
90.4(6) H(1)-Ru(3)-B(5)
81.9(1) B(5)-Ru(3)-C(17)
84.1(4) C(18)-Ru(3)-P(2)
115.5(5) Ru(3)-P(2)-C(20)
87.5(4)
96.3(6)
98.5(4)
116.0(4)
Ru(3)-C(18)-O(18) 179.1(10) Ru(3)-P(2)-C(19)
113.4(4)
distances (Ph)
angles (Ph)
ring
mean
range
mean
range
116.7-112.5
115.0-126.1
C(11)-C(16)
C(21)-C(26)
1.38(1)
1.38(1)
1.363-1.394
1.363-1.391
120(2)
120(4)
An important feature of the structure of 5 is the
presence of the hydrido ligand H(1) bridging Ru(2)-
Ru(3) which, as expected, is the longest of the three
metal-metal distances. The location of H(1) was based
on potential-energy minimization calculations,5 but the
µ-H-Ru distances (1.78 Å) are in the normal range6 and
compare with 1.72 Å for the hydrido bridge in [Ru3(µ-
H)(µ-σ:η5-7-NMe3-7-CB10H9)(CO)7(PPh3)].4 Each Ru atom
in 5 carries two terminally bound CO groups, but Ru(2)
and Ru(3) are also ligated by PMe2Ph molecules. The
distances Ru(2)-P(1) [2.331(3) Å] and Ru(3)-P(2)
[2.285(3) Å] are in excellent agreement with the data
for such bonds in related structures.7 Atom P(1) is
transoid to Ru(1) [Ru(1)-Ru(2)-P(1) ) 171.4(1)°] while
P(2) is cisoid to B(5) [P(2)-Ru(3)-B(5) ) 93.3(4)°].
The NMR data for 5 (Tables 2 and 3) are in agreement
with the results of the X-ray diffraction study, and the
data for 3 and 4 with similar structures are also in
at δ 32.3 is in the chemical shift region for a B-HFRu
system, and in accord with this assignment the 1H-
11B coupling was 70 Hz. The asymmetry in 5 would lead
to nonequivalence of the cage CMe groups. Thus as
expected there are two signals (δ 2.39 and 2.49) for these
1
groups in the H NMR spectrum and four (δ 62.6, 74.1
(CMe); δ 32.7, 33.6 (CMe)) in the 13C{1H} NMR spec-
trum. Although five rather than six CO resonances are
observed in the latter spectrum, one signal corresponded
in intensity to an overlap of two peaks (Table 2).
The 1H NMR data for the monosubstituted phosphine
complex 3 revealed signals for the Ru(µ-H)Ru and
B-HFRu groups at δ -17.51 and -9.30, respectively,
and for the cage CMe groups at δ 2.36 and 2.48. The
13C{1H} NMR spectrum displayed seven peaks for the
nonequivalent CO ligands, and there were the expected
resonances for the cage CMe groups at δ 62.1 and 73.2
(CMe) and at δ 32.5 and 33.3 (CMe). In a fully coupled
11B NMR spectrum a singlet at δ 43.0 could be assigned
to the B-Ru group and a doublet [J (HB) ) 72 Hz] at δ
32.1 to the B-HFRu moiety. The 31P{1H} NMR
spectrum showed a singlet at δ 42.0. Complex 3 is
assigned a structure in which the PPh3 group is at-
tached to the Ru atom involved in the B-HFRu bridge
system. The three-center two-electron bond corresponds
to an incipient oxidative addition at the metal center.
The structural assignment is made by analogy with a
recent X-ray diffraction study of [Ru3(µ-H)(µ-σ:η5-7-
NMe3-7-CB10H9)(CO)7(PPh3)] which established that the
phosphine group in this molecule is similarly placed on
1
accord with the formulations for these species. The H
NMR spectrum of 5 shows diagnostic resonances for the
Ru(µ-H)Ru8 and B-HFRu1,2b groups at δ -16.99 and
-10.08, respectively, with the latter signal seen as a
quartet [J (BH) ) 70 Hz] as expected. In the fully
coupled 11B NMR spectrum there is a diagnostic singlet
peak at δ 42.1 for the B-Ru group and doublet reso-
nances for the other signals. However, the resonance
(5) Orpen, A. G. J . Chem. Soc., Dalton Trans. 1980, 2509.
(6) Teller, R. G.; Bau, R. Struct. Bonding 1981, 44, 1.
(7) Orpen, A. G.; Brammer, L.; Allen, F. H.; Kennard, O.; Watson,
D. G.; Taylor, R. J . Chem. Soc., Dalton Trans. 1989, S1.
(8) Kaesz, H. D.; Saillant, R. B. Chem. Rev. 1972, 72, 231.

5106 Organometallics, Vol. 15, No. 24, 1996
Liao et al.
latter is revealed in the fully coupled 11B NMR spectrum
by a doublet resonance at δ 18.3 [J (HB) ) 78 Hz]. There
are two resonances (δ -11.4 and -0.1) for the non-
equivalent PMe3 ligands in the 31P{1H} NMR spectrum.
In a dimetal complex with a B-HFRu bridging unit it
is usual for the latter to involve the B atom in the â
Ch a r t 2
site with respect to the carbons in the open CCBBB face
coordinated to the Ru.2 For 7 this configuration would
lead to a plane of symmetry through the Ru and P
atoms, the B atom in the â site, and the midpoint of
the cage C-C connectivity. This symmetrical structure
1
is supported by the H NMR spectrum which displays
only one resonance (δ 2.37) for the cage CMe protons.
Correspondingly, in the 13C{1H} NMR spectrum the
equivalence of the cage CMe fragments results in only
two signals (δ 63.2 (CMe) and 32.0 (CMe)) for these
groups. The observed pattern of only two peaks for the
CO resonances is also in agreement with the symmetry.
The resonance at δ 206.2 can be assigned to the
carbonyl-carbon nuclei in the cisoid Ru(CO)2 group
coordinated by the open face of the nido-C2B9 cage, the
two carbonyls lying on either side of the symmetry
plane, while the doublet-of-doublets at δ 204.3 is at-
tributable to the equivalent carbonyls of the transoid
Ru(CO)2 fragment, with 31P-13C coupling to the non-
equivalent PMe3 groups.
Reaction of 2 with Ph2PCH2PPh2 (dppm) afforded
[Ru3(µ-dppm)(CO)6(η5-7,8-Me2-7,8-C2B9H9)] (8) charac-
terized by the data given in Tables 1-3. NMR spec-
troscopy indicated that the molecular structure is
similar to that of 2, with the dppm ligand bridging the
Ru-Ru bond formed by the two metal atoms not
pentahapto coordinated by the cage. The absence of
B-Ru and Ru(µ-H)Ru groups in the molecule, akin to
those present in 3-5, may be due to the µ-dppm group
occupying the bridging site thus impeding the fully
oxidative step from a B-HFRu linkage into B-Ru and
Ru(µ-H)Ru. The two B-HFRu groups in 8 are non-
equivalent since one employs a BH group â to the
carbons in the C2B3 ring while the other uses a BH bond
R to the ring carbons. Nevertheless, in the 1H NMR
spectrum only one very broad quartet signal is seen at
δ -9.11. However, its relative intensity indicated that
it was due to two protons. Evidently the resonances for
the two B-HFRu groups are essentially coincident in
the 1H NMR spectrum as was observed for 2. However,
two doublet resonances for the B-HFRu groups were
seen at δ 23.0 and 15.6 in a fully coupled 11B NMR
an Ru atom involved in a B-HFRu bridge.4 An
alternative structure for 3 with the PPh3 group linked
to the ruthenium atom which forms the Ru-B σ-bond
might be thought more likely because substitution of a
CO molecule by the superior donor PPh3 would increase
the nucleophilicity of the ruthenium center to which it
is attached. This would promote oxidative addition at
that center so as to yield the B-Ru and Ru(µ-H)Ru
units. However, as discussed previously,4 a structure
with the PPh3 ligand attached to the ruthenium which
is also σ-bonded to a cage boron might be kinetically
unstable and undergo rearrangement of its B-Ru and
B-HFRu groups between adjacent boron atoms in the
CCBBB ring. This could be facilitated by migration of
hydrogen from the Ru(µ-H)Ru bridge to a B-HFRu site.
The tricyclohexylphosphine complex [Ru3(µ-H)(µ-σ:η5-
7,8-Me2-7,8-C2B9H8)(CO)7(PCy3)] (6) was prepared by
treating 2 with 1 mol equiv of PCy3 in CH2Cl2 at room
temperature. The NMR data (Tables 2 and 3) for 6 are
in accord with a formulation akin to 3. Resonances in
the 1H NMR spectrum due to the Ru(µ-H)Ru and
B-HFRu groups are clearly seen at δ -18.37 and
-10.10, respectively. In a fully coupled 11B NMR
spectrum peaks for the B-Ru and B-HFRu groups
occur as a singlet and a doublet [J (HB) ) 73 Hz],
respectively, at δ 43.1 and 32.4. The NMR data for 3
(Tables 1 and 2) are very similar.
1
spectrum, with H-11B couplings of ca. 70-80 Hz. As
expected due to the asymmetry, there are two reso-
nances in the 31P{1H} NMR spectrum (Table 3), each a
doublet [J (PP) ) 25 Hz]. The nonequivalence of the
1
CMe cage vertices is indicated in the H NMR spectrum
by the appearance of peaks at δ 2.17 and 2.47 and in
the 13C{1H} NMR spectrum by resonances at δ 60.0 and
73.2 (CMe) and δ 29.8 and 32.8 (CMe). The nonequiva-
In contrast, with the reactions with PPh3, PMe2Ph,
and PCy3, that between 2 and PMe3 afforded [Ru2(CO)4-
(PMe3)2(η5-7,8-Me2-7,8-C2B9H9)] (7) (Chart 2), a di-
rather than a triruthenium complex. This product was
characterized by microanalytical and NMR data (Tables
1
lent PCH2P hydrogens were revealed in the H NMR
spectrum by doublets-of-doublets-of-doublets at δ 4.62
and 4.86 [J (HH) ) 14; J (PH) ) 11 and 11 Hz].
Reactions between compound 2 and some nitrogen
bases were next investigated. Reaction with Me2NCH2-
NMe2 afforded a mixture of the two diruthenium species
[Ru2(µ-η5-7,8-Me2-10-CH2NMe2-7,8-C2B9H8)(CO)5] (9) and
[Ru2(CO)5(NHMe2)(η5-7,8-Me2-7,8-C2B9H9)] (10). Evi-
dently the reaction is complex proceeding with fission
1
1-3). In the H NMR spectrum there is a diagnostic
signal for the B-HFRu group at δ -11.02, appearing
as a doublet of quartets [J (BH) ) 78, J (PH) ) 31 Hz].
The 31P-1H coupling may be attributed to the PMe3
group which is transoid to the B-HFRu bridge. The

Carborane Complexes of Ruthenium
Organometallics, Vol. 15, No. 24, 1996 5107
Ta ble 5. Selected In ter n u clea r Dista n ces (Å) a n d An gles (d eg) for
[Ru 2(µ-η5-7,8-Me2-10-CH2NMe2-7,8-C2B9H8)(CO)5] (9), w ith Estim a ted Sta n d a r d Devia tion s in P a r en th eses
Ru(1)-C(1)
Ru(1)-B(5)
C(1)-C(2)
C(1)-C(3)
C(2)-C(4)
B(3)-B(8)
B(4)-B(8)
B(5)-B(10)
B(7)-B(8)
B(9)-B(10)
N(1)-C(6)
C(9)-O(9)
C(10)-O(10)
2.244(4)
2.240(5)
1.700(8)
1.523(6)
1.521(6)
1.771(6)
1.787(8)
1.782(7)
1.748(7)
1.782(7)
1.485(6)
1.163(6)
1.157(6)
Ru(1)-C(2)
Ru(1)-C(8)
C(1)-B(5)
C(2)-B(3)
B(3)-H(3)
B(3)-Ru(2)
B(4)-B(9)
B(6)-B(7)
B(7)-B(11)
B(9)-B(11)
N(1)-C(7)
Ru(2)-C(10)
C(11)-O(11)
2.242(5)
1.857(5)
1.738(7)
1.735(6)
1.104
2.410(5)
1.793(7)
1.727(9)
1.756(8)
1.774(9)
1.522(7)
1.865(5)
1.153(6)
Ru(1)-B(3)
Ru(1)-C(9)
C(1)-B(6)
2.199(6)
1.887(4)
1.737(8)
1.720(7)
1.775(9)
1.796
1.599(6)
1.768(10)
1.776(9)
1.784(9)
2.233(3)
1.866(5)
1.161(7)
Ru(1)-B(4)
Ru(1)-Ru(2)
C(1)-B(10)
C(2)-B(7)
B(3)-B(7)
B(4)-B(5)
B(5)-B(9)
B(6)-B(11)
B(8)-B(11)
C(5)-N(1)
C(8)-O(8)
Ru(2)-C(12)
2.274(4)
2.727(1)
1.707(6)
1.707(7)
1.777(7)
1.834(8)
1.796(7)
1.749(7)
1.748(7)
1.527(6)
1.150(7)
1.923(6)
C(2)-B(6)
B(3)-B(4)
H(3)-Ru(2)
B(4)-C(5)
B(6)-B(10)
B(8)-B(9)
B(10)-B(11)
N(1)-Ru(2)
Ru(2)-C(11)
C(12)-O(12)
C(8)-Ru(1)-C(9)
B(4)-Ru(1)-Ru(2)
Ru(1)-B(3)-H(3)
C(5)-N(1)-C(6)
C(6)-N(1)-Ru(2)
Ru(1)-Ru(2)-B(3)
H(3)-Ru(2)-N(1)
N(1)-Ru(2)-C(10)
N(1)-Ru(2)-C(11)
H(3)-Ru(2)-C(12)
Ru(2)-C(10)-O(10)
87.6(2)
C(1)-Ru(1)-Ru(2)
B(5)-Ru(1)-Ru(2)
B(3)-H(3)-Ru(2)
C(5)-N(1)-C(7)
C(7)-N(1)-Ru(2)
Ru(1)-Ru(2)-H(3)
Ru(1)-Ru(2)-C(10)
Ru(1)-Ru(2)-C(11)
C(10)-Ru(2)-C(11)
N(1)-Ru(2)-C(12)
Ru(2)-C(11)-O(11)
134.1(1)
C(2)-Ru(1)-Ru(2)
C(8)-Ru(1)-Ru(2)
Ru(1)-B(4)-C(5)
C(6)-N(1)-C(7)
Ru(1)-C(8)-O(8)
Ru(1)-Ru(2)-N(1)
B(3)-Ru(2)-C(10)
B(3)-Ru(2)-C(11)
Ru(1)-Ru(2)-C(12)
C(10)-Ru(2)-C(12)
Ru(2)-C(12)-O(12)
92.8(1)
98.8(1)
111.5(3)
106.9(4)
177.0(4)
92.6(1)
133.8(2)
95.7(2)
176.3(2)
97.0(2)
B(3)-Ru(1)-Ru(2)
C(9)-Ru(1)-Ru(2)
B(4)-C(5)-N(1)
C(5)-N(1)-Ru(2)
Ru(1)-C(9)-O(9)
B(3)-Ru(2)-N(1)
H(3)-Ru(2)-C(10)
H(3)-Ru(2)-C(11)
B(3)-Ru(2)-C(12)
C(11)-Ru(2)-C(12)
57.4(1)
101.6(2)
110.6(4)
112.0(2)
176.7(4)
82.2(1)
159.0(3)
91.5(2)
128.8(2)
91.2(2)
76.3(2)
114.4(1)
108.0(4)
112.8(2)
50.2(1)
87.0(2)
93.0(2)
177.8(2)
104.0(2)
177.0(5)
124.2(1)
110.1(2)
108.3(3)
108.7(3)
74.6(2)
84.4(2)
85.5(2)
87.9(2)
90.7(2)
176.6(5)
172.1(3)
F igu r e 3. Molecular structure of [Ru2(CO)5(NHMe2)(η5-
7,8-Me2-7,8-C2B9H9)] (10), showing the crystallographic
labeling scheme. Except for H(4), hydrogen atoms have
been omitted for clarity, and thermal ellipsoids are shown
at 50% probability level.
F igu r e 2. Molecular structure of [Ru2(µ-η5-7,8-Me2-10-
CH2NMe2-7,8-C2B9H8)(CO)5] (9), showing the crystallo-
graphic labeling scheme. Except for H(3), hydrogen atoms
have been omitted for clarity, and thermal ellipsoids are
shown at 50% probability level.
be different. There are five terminally bonded CO
ligands, two coordinated to Ru(1) and three to Ru(2).
Overall the molecule is electronically saturated for a
dimetal compound with 34 valence electrons, with the
cage contributing 8 and the CO groups 10 electrons.
The structure of 10 is shown in Figure 3, and the
important bond distances and angles are listed in Table
6. The Ru(1)-Ru(2) bond distance [2.732(1) Å] is
essentially the same as that in 9. The nido-C2B9 cage
ligates Ru(1) and forms an agostic bridge from the
B(4)H(4) vertex to Ru(2). The latter carries an NHMe2
ligand which lies in a cisoid position to the Bâ-HFRu(2)
group. Two of the CO molecules are coordinated to
Ru(1) and three to Ru(2). The molecule is electronically
saturated with 34 valence electrons. At the present
time the pathway for the formation of 9 and 10 from 2
and Me2NCH2NMe2, which occurs under mild condi-
tions, is unresolved, but interestingly it would seem that
the donor reagent is fragmented into C(H)NMe2 and
NHMe2 groups and that 2 must decompose to form Ru2-
(CO)5(η5-7,8-Me2-7,8-C2B9H9) fragments. The overall
of metal-metal bonds in 2 and a N-CH2 bond in
N,N,N′,N′-tetramethyldiaminomethane. This unex-
pected result prompted establishment of the structures
of these molecules by single-crystal X-ray diffraction
studies.
The molecular structure of 9 is shown in Figure 2,
and selected parameters are listed in Table 5. The
Ru(1)-Ru(2) bond [2.727(1) Å] is spanned by the nido-
7,8-Me2-10-CH2NMe2-7,8-C2B9H8 group. The cage sys-
tem is coordinated to Ru(1) by its open CCBBB face in
the customary pentahapto manner while simulta-
neously forming exopolyhedral B(3)-H(3)FRu(2) and
B(4)-C(5)-N(1) bridges to Ru(2). The B-HFRu unit
involves B(3), the boron atom R to the carbons in the
CCBBB ring, while the CH2NMe2 fragment is attached
to B(4) which is in the â site with respect to the carbons
in the CCBBB ring. Formally the CH2NMe2 cage
substituent results from insertion of a C(H)NMe2 group
into a BH bond, although the actual pathway may well

5108 Organometallics, Vol. 15, No. 24, 1996
Liao et al.
Ta ble 6. Selected In ter n u clea r Dista n ces (Å) a n d An gles (d eg) for [Ru 2(CO)5(NHMe2)(η5-7,8-Me2-7,8-C2B9H9)]
(10), w ith Estim a ted Sta n d a r d Devia tion s in P a r en th eses
Ru(1)-C(1)
Ru(1)-B(5)
C(1)-C(2)
C(1)-C(3)
C(2)-C(4)
B(4)-H(4)
B(4)-Ru(2)
B(6)-B(7)
B(7)-B(11)
B(9)-B(11)
Ru(2)-C(11)
C(11)-O(11)
N-C(15)
2.314(6)
2.277(7)
1.617(9)
1.533(10)
1.526(10)
1.101
2.419(7)
1.739(12)
1.767(11)
1.781(11)
1.881(7)
1.164(9)
1.496(8)
Ru(1)-C(2)
Ru(1)-C(5)
C(1)-B(5)
2.316(6)
1.844(7)
1.731(10)
1.712(10)
1.800(11)
1.816(11)
1.441
1.720(12)
1.786(11)
1.759(12)
1.873(7)
1.161(9)
Ru(1)-B(3)
Ru(1)-C(6)
C(1)-B(6)
C(2)-B(6)
B(3)-B(7)
B(4)-B(8)
B(5)-B(9)
B(6)-B(11)
B(8)-B(11)
C(5)-O(5)
Ru(2)-C(13)
C(13)-O(13)
2.271(7)
1.867(7)
1.732(10)
1.724(10)
1.738(10)
1.768(10)
1.790(11)
1.756(12)
1.760(11)
1.170(9)
1.904(8)
1.159(11)
Ru(1)-B(4)
Ru(1)-Ru(2)
C(1)-B(10)
C(2)-B(7)
B(3)-B(8)
B(4)-B(9)
B(5)-B(10)
B(7)-B(8)
B(9)-B(10)
C(6)-O(6)
Ru(2)-N
2.203(7)
2.732(1)
1.720(10)
1.706(10)
1.780(10)
1.765(10)
1.774(10)
1.762(11)
1.782(12)
1.158(9)
2.183(5)
1.477(8)
C(2)-B(3)
B(3)-B(4)
B(4)-B(5)
H(4)-Ru(2)
B(6)-B(10)
B(8)-B(9)
B(10)-B(11)
Ru(2)-C(12)
C(12)-O(12)
N-C(14)
C(5)-Ru(1)-C(6)
Ru(1)-B(4)-Ru(2)
Ru(1)-Ru(2)-B(4)
H(4)-Ru(2)-C(11)
C(11)-Ru(2)-C(12)
C(11)-Ru(2)-C(13)
H(4)-Ru(2)-N
89.9(3)
72.3(2)
50.2(2)
150.5(4)
89.1(3)
100.1(3)
86.0(3)
C(5)-Ru(1)-Ru(2)
B(4)-H(4)-Ru(2)
Ru(1)-Ru(2)-H(4)
Ru(1)-Ru(2)-C(12)
Ru(1)-Ru(2)-C(13)
C(12)-Ru(2)-C(13)
C(11)-Ru(2)-N
96.0(2)
C(6)-Ru(1)-Ru(2)
Ru(1)-C(5)-O(5)
Ru(1)-Ru(2)-C(11)
B(4)-Ru(2)-C(12)
B(4)-Ru(2)-C(13)
Ru(1)-Ru(2)-N
96.2(2)
175.5(6)
85.0(2)
89.3(3)
124.7(3)
91.0(1)
Ru(1)-B(4)-H(4)
Ru(1)-C(6)-O(6)
B(4)-Ru(2)-C(11)
H(4)-Ru(2)-C(12)
H(4)-Ru(2)-C(13)
B(4)-Ru(2)-N
92.6(2)
176.4(6)
135.2(3)
92.4(3)
109.3(4)
89.0(2)
143.9(3)
65.6(3)
87.9(2)
174.9(2)
92.3(3)
92.0(2)
176.7(6)
109.8(5)
C(12)-Ru(2)-N
178.4(2)
177.4(7)
C(13)-Ru(2)-N
Ru(2)-N-C(14)
88.7(3)
115.8(4)
Ru(2)-C(11)-O(11)
Ru(2)-N-C(15)
176.6(7)
113.6(4)
Ru(2)-C(12)-O(12)
C(14)-N-C(15)
Ru(2)-C(13)-O(13)
low yield of 9 and 10 of ca. 25% is therefore not
surprising.
The NMR data (Tables 2 and 3) for 9 and 10 are as
expected from the crystal structure determinations.
Both species show characteristic quartet resonances in
1
the H NMR spectra for the B-HFRu bridges, that for
9 at δ -6.91 [J (BH) ) 77 Hz] and that for 10 at δ -8.19
[J (BH) ) 76 Hz]. Correspondingly, in the 11B fully
coupled NMR spectra there are doublets for these
groups at δ 24.9 [J (HB) ) 77] (9) and δ 26.6 [J (HB) )
1
76] (10). In the H NMR spectrum of 9 the signals for
the diastereotopic pair of BCH2N protons are at δ 2.31
and 2.42. In both molecules the cage CMe groups are
nonequivalent, and this is reflected in the 1H NMR
spectra with resonances for these groups at δ 2.22 and
2.30 (9) and δ 2.35 and 2.37 (10). However, in the 13C-
{1H} NMR spectra, although the two resonances (9, δ
30.2 and 33.0; 10, δ 31.8 and 31.9) anticipated for the
CMe nuclei are observed, only one very broad peak is
seen in the region for the CMe nuclei (9, δ 66.9; 10, δ
65.1). This feature is not uncommon in 13C{1H} NMR
spectra of metallacarboranes being evidently due to an
overlap of signals whereas peaks in the 1H NMR spectra
are better resolved.
F igu r e 4. Molecular structure of [Ru2(CO)5(NC5H5)(η5-7,8-
Me2-7,8-C2B9H9)] (11), showing the crystallographic label-
ing scheme. Except for H(4), hydrogen atoms have been
omitted for clarity, and thermal ellipsoids are shown at 50%
probability level.
resonances for the B-HFRu groups at δ -7.82 [J (BH)
) 80 Hz] and δ -5.28 [J (BH) ) 67 Hz], respectively.
Treatment of 2 with pyridine in CH2Cl2 at room
temperature gave a chromatographically separable
mixture of the mono- and bis(pyridine)diruthenium
complexes [Ru2(CO)5(NC5H5)(η5-7,8-Me2-7,8-C2B9H9)] (11)
and [Ru2(CO)4(NC5H5)2(η5-7,8-Me2-7,8-C2B9H9)] (12),
data for which are given in Tables 1-3. The structure
of 11 was determined by X-ray diffraction and is shown
in Figure 4. Selected bond distances and angles are
listed in Table 7. The molecule is structurally very
similar to 10 but with a pyridine ligand replacing the
NHMe2 group. Again there is a Bâ-HFRu bridge
Con clu sion s
There are several interesting aspects to the results
described herein. Previous studies1 showed that the
reaction between nido-7,8-C2B9H13 and [Ru3(CO)12]
yielded exclusively the monoruthenium complex 1a
whereas the present study reveals that the correspond-
ing reaction with nido-7,8-Me2-7,8-C2B9H11 gives a
mixture of 1b and 2 in which the latter predominates.
Interestingly, 1b is not formed via the intermediacy of
2 since heating the latter at reflux temperatures in CH2-
Cl2 does not produce the former. The new triruthenium
species 2 is likely to become a useful synthon providing
a link between ruthenacarborane chemistry, where our
present knowledge is very limited, and di- and tri-
nuclear ruthenium carbonyl chemistry which has been
extensively studied.9 In this context it is noteworthy
that several of the structures established are without
precedent. The reactions of 2 with the various donor
involving B(4) the boron in the â site in the CCBBB ring.
Not surprisingly the Ru(1)-Ru(2) distance in 11 [2.747(1)
Å] is essentially the same as that in 10. An X ray
diffraction study on 12 was incomplete due to the poor
quality of the crystal, but nevertheless it was apparent
that it had a similar structure to 11 with the second
pyridine molecule transoid to the metal-metal bond.
1
In their H NMR spectra both 11 and 12 show quartet

Carborane Complexes of Ruthenium
Organometallics, Vol. 15, No. 24, 1996 5109
Ta ble 7. Selected In ter n u clea r Dista n ces (Å) a n d An gles (d eg) for [Ru 2(CO)5(NC5H5)(η5-7,8-Me2-7,8-C2B9H9)]
(11), w ith Estim a ted Sta n d a r d Devia tion s in P a r en th eses
Ru(1)-C(1)
Ru(1)-B(5)
C(1)-C(2)
2.315(5)
2.270(6)
1.629(7)
1.525(7)
1.532(7)
1.102
2.416(6)
1.738(9)
1.744(9)
1.779(9)
1.880(6)
1.147(8)
1.351(7)
1.359(8)
Ru(1)-C(2)
Ru(1)-C(11)
C(1)-B(5)
2.315(5)
1.868(6)
1.719(7)
1.722(8)
1.782(9)
1.804(8)
1.762
1.749(9)
1.778(9)
1.777(9)
1.917(6)
1.152(7)
1.375(8)
Ru(1)-B(3)
Ru(1)-C(12)
C(1)-B(6)
2.262(6)
1.853(6)
1.731(8)
1.721(8)
1.775(9)
1.776(9)
1.772(8)
1.760(9)
1.754(9)
1.167(7)
1.886(6)
1.161(8)
1.354(9)
Ru(1)-B(4)
Ru(1)-Ru(2)
C(1)-B(10)
C(2)-B(7)
2.191(6)
2.747(1)
1.716(8)
1.727(8)
1.782(9)
1.760(9)
1.772(8)
1.757(9)
1.769(9)
1.157(8)
2.168(4)
1.328(7)
1.368(8)
C(1)-C(3)
C(2)-B(3)
C(2)-B(6)
C(2)-C(4)
B(3)-B(4)
B(4)-B(5)
H(4)-Ru(2)
B(6)-B(10)
B(8)-B(9)
B(10)-B(11)
Ru(2)-C(14)
C(14)-O(14)
C(21)-C(22)
B(3)-B(7)
B(3)-B(8)
B(4)-H(4)
B(4)-Ru(2)
B(6)-B(7)
B(4)-B(8)
B(4)-B(9)
B(5)-B(10)
B(7)-B(8)
B(9)-B(10)
C(12)-O(12)
Ru(2)-N(1)
N(1)-C(21)
C(23)-C(24
B(5)-B(9)
B(6)-B(11)
B(8)-B(11)
C(11)-O(11)
Ru(2)-C(15)
C(15)-O(15)
C(22)-C(23)
B(7)-B(11)
B(9)-B(11)
Ru(2)-C(13)
C(13)-O(13)
N(1)-C(25)
C(24)-C(25)
C(11)-Ru(1)-C(12)
B(4)-Ru(1)-Ru(2)
Ru(1)-B(4)-H(4)
Ru(1)-Ru(2)-B(4)
H(4)-Ru(2)-C(13)
C(13)-Ru(2)-C(14)
C(13)-Ru(2)-C(15)
H(4)-Ru(2)-N(1)
Ru(2)-C(13)-O(13)
Ru(2)-N(1)-C(25)
88.4(2)
C(1)-Ru(1)-Ru(2)
B(5)-Ru(1)-Ru(2)
B(4)-H(4)-Ru(2)
Ru(1)-Ru(2)-H(4)
Ru(1)-Ru(2)-C(14)
Ru(1)-Ru(2)-C(15)
C(14)-Ru(2)-C(15)
C(13)-Ru(2)-N(1)
Ru(2)-C(14)-O(14)
127.8(1)
85.2(1)
113.0(2)
74.3(2)
174.6(2)
85.4(2)
99.1(2)
177.0(2)
176.9(6)
C(2)-Ru(1)-Ru(2)
C(11)-Ru(1)-Ru(2)
Ru(1)-C(11)-O(11)
Ru(1)-Ru(2)-C(13)
B(4)-Ru(2)-C(14)
B(4)-Ru(2)-C(15)
Ru(1)-Ru(2)-N(1)
C(14)-Ru(2)-N(1)
Ru(2)-C(15)-O(15)
129.6(1)
95.5(2)
178.9(5)
84.3(2)
125.9(2)
134.9(2)
94.2(1)
88.4(2)
177.4(5)
B(3)-Ru(1)-Ru(2)
C(12)-Ru(1)-Ru(2)
Ru(1)-C(12)-O(12)
B(4)-Ru(2)-C(13)
H(4)-Ru(2)-C(14)
H(4)-Ru(2)-C(15)
B(4)-Ru(2)-N(1)
C(15)-Ru(2)-N(1)
Ru(2)-N(1)-C(21)
87.4(2)
57.2(2)
114.7(2)
49.7(1)
88.9(3)
92.9(2)
89.7(3)
88.1(2)
178.1(6)
119.7(3)
96.7(2)
176.6(5)
89.6(2)
101.1(3)
159.7(3)
87.4(2)
92.8(2)
123.6(3)
molecules afforded di- or triruthenium complexes de-
pending on the donor reagent. Apparently nitrogen
bases in particular favor formation of diruthenium
complexes. However, further studies are merited to
delineate which classes of donor molecule promote
removal of a ruthenium fragment from the triruthenium
precursor and which preserve the trinuclear framework.
a red band. Removal of solvent in vacuo from the
eluate, followed by crystallization from CH2Cl2 layered
with petroleum ether, gave crystals of [Ru(CO)3(η5-7,8-
Me2-7,8-C2B9H9)] (1b) (0.05 g).
Rea ction s of [Ru 3(CO)8(η5-7,8-Me2-7,8-C2B9H9)]
(2) w ith P h osp h in es. (i) A mixture of 2 (0.12 g, 0.17
mmol) and PPh3 (0.045 g, 0.17 mmol) in THF (30 mL)
was stirred at room temperature for ca. 15 h. Solvent
was removed in vacuo and the dark red residue was
dissolved in a minimum volume (ca. 5 mL) of CH2Cl2-
petroleum ether (1:1) and chromatographed. Elution
with CH2Cl2-petroleum ether (2:3) gave a dark yellow
fraction, which after removal of solvent in vacuo yielded
a red solid. The latter was crystallized from a CH2Cl2
solution on which a layer of petroleum ether was placed
giving red crystals of [Ru3(µ-H)(µ-σ:η5-7,8-Me2-7,8-
C2B9H8)(CO)7(PPh3)] (3) (0.085 g).
Exp er im en ta l Section
Gen er a l Con sid er a tion s. Solvents were distilled
from appropriate drying agents under nitrogen prior to
use. Petroleum ether refers to that fraction of boiling
point 40-60 °C. All reactions were carried out under
an atmosphere of dry nitrogen using Schlenk line
techniques. Chromatography columns (ca. 15 cm in
length and ca. 2 cm in diameter) were packed with silica
gel (Aldrich, 70-230 mesh). TLC was performed on
preparative UNIPLATES (silica gel G; Analtech). The
compound nido-7,8-Me2-7,8-C2B9H11 was prepared from
(ii) Similarly, a mixture of 2 (0.34 g, 0.50 mmol) and
PPh3 (0.26 g, 1.0 mmol) was refluxed in THF (30 mL)
for 2 h. After removal of solvent in vacuo the dark red
residue dissolved in the minimum volume (ca. 5 mL) of
CH2Cl2-petroleum ether (1:1) was chromatographed.
Elution with CH2Cl2-petroleum ether (1:1) removed an
orange-red fraction from which red crystals of [Ru3(µ-
H)(µ-σ:η5-7,8-Me2-7,8-C2B9H8)(CO)6(PPh3)2] (4) (0.22 g)
were obtained after crystallization from CH2Cl2-
petroleum ether, as described above.
closo-1,2-Me2-1,2-C2B10H10 using a procedure similar to
10
that for nido-7,8-C2B9H13
.
The NMR spectra were
recorded at the following frequencies: 1H 360.1, 13C
90.6, 31P 145.7, and 11B 115.5 MHz.
Rea ction of n id o-7,8-Me2-7,8-C2B9H11 w ith [Ru 3-
(CO)12]. The compounds [Ru3(CO)12] (0.34 g, 0.50
mmol) and nido-7,8-Me2-7,8-C2B9H11 (0.25 g, 1.50 mmol)
were heated to reflux in CH2Cl2 (40 mL) for 24 h. The
mixture was then cooled to room temperature and ca. 2
g of silica gel added. Solvent was removed in vacuo
affording a reddish powder which was transferred to the
top of a chromatography column. Elution with CH2Cl2-
petroleum ether (1:4) gave an orange-red fraction.
Removal of solvent in vacuo followed by crystallization
from petroleum ether yielded orange-red microcrystals
of [Ru3(CO)8(η5-7,8-Me2-7,8-C2B9H9)] (2) (0.14 g). Fur-
ther elution with CH2Cl2-petroleum ether (1:1) afforded
(iii) Compound 2 (0.13 g, 0.19 mmol) in CH2Cl2 (5 mL)
was treated with an excess of PMe2Ph (1 mL, 0.5 M THF
solution, 0.50 mmol) and the solution stirred for 30 min.
Use of TLC showed that no starting material remained.
Petroleum ether (40 mL) was layered over the solution
and the mixture placed in a freezer overnight. This
procedure gave red crystals of [Ru3(µ-H)(µ-σ:η5-7,8-Me2-
7,8-C2B9H8)(CO)6(PMe2Ph)2] (5) (0.13 g).
(iv) A mixture of 2 (0.17 g, 0.24 mmol) and PCy3 (0.068
g, 0.24 mmol) was stirred at room temperature in CH2-
Cl2 (30 mL) for 3 h. Solvent was removed in vacuo, and
the dark red residue was dissolved in a minimum
volume (5 mL) of CH2Cl2-petroleum ether (1:1) and
chromatographed. Elution with CH2Cl2-petroleum
ether (2:3) removed a red band. Evaporation of solvent
(9) Deeming, A. J . In Comprehensive Organometallic Chemistry II;
Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds.; Pergamon Press;
Oxford, U.K., 1995; Vol. 7 (Shriver, D. F., Bruce, M. I., Eds.), Chapter
12.
(10) Hlatky, G. G.; Crowther, D. J . Inorg. Synth., in press. Young,
D. A. T.; Wiersma, R. J .; Hawthorne, M. F. J . Am. Chem. Soc., 1971,
93, 5687.

5110 Organometallics, Vol. 15, No. 24, 1996
Ta ble 8. Da ta for X-r a y Cr ysta l Str u ctu r e An a lysesa
Liao et al.
5
9
10
11
cryst dimens/mm
formula
Mr
0.21 × 0.28 × 0.33
C26H37B9O6P2Ru3
908.0
0.18 × 0.33 × 0.36
C12H22B9NO5Ru2
559.7
0.05 × 0.12 × 0.39
C11H22B9NO5Ru2
547.7
0.20 × 0.34 × 0.53
C14H20B9NO5Ru2
581.7
cryst color, shape
cryst system
space group (No.)
orange irregular crystal
monoclinic
P21/c (No. 14)
19.313(2)
15.448(2)
14.516(3)
95.67(1)
4323(1)
4
red parallelepiped
monoclinic
P21/c (No. 14)
15.511(2)
10.205(2)
14.818(2)
114.78(1)
2129.6(6)
4
orange thin plate
monoclinic
P21/c (No. 14)
7.892(2)
14.303(2)
19.039(3)
96.91(2)
2233.4(6)
4
red irregular crystal
orthorhombic
Pbca (No. 61)
11.842(1)
14.240(1)
26.405(1)
a/Å
b/Å
c/Å
â/deg
V/Å3
Z
4452.7(5)
8
1.736
13.56
2272
d
calcd/g cm-3
1.395
11.19
1792
1.746
14.14
1096
1.705
14.09
1072
µ(Mo KR)/cm-1
F(000)/e
2θ range/deg
T/K
3-40
292
3-40
292
3-40
292
3-40
292
no. of reflns measd
4439
2233
2302
2604
no. of unique reflns
4016
1974
1995
2065
no. of obsd reflns
3216
1838
1596
1850
Rint
0.021
n ) 4
0.0031
0.027
n ) 4
0.0001
0.023
n ) 4
0.0001
0.017
n ) 4
0.000 03
criterion for obsd n [Fo g nσ(Fo)]
weighting factor/g
reflcn limits
h
k
l
-18 to 18
0 to 14
0 to 13
0.0545 (0.0608)
1.57/-0.54
-14 to 13
0 to 9
0 to 14
0.0238 (0.0313)
0.43/-0.28
0 to 7
0 to 13
-18 to 18
0.0252 (0.0272)
0.36/-0.43
-2 to 11
-3 to 13
-6 to 25
0.0252 (0.0311)
0.36/-0.38
R (R′)b
final electron density diff features
(max/min)/e Å-3
S (goodness-of-fit)
1.50
1.72
1.17
1.71
a
Data collected on an Enraf Nonius CAD4-F automated diffractometer operating in the ω-2θ scan mode; graphite-monochromated
Mo KR X-radiation, λh ) 0.710 73. Refinement was by block full-matrix least-squares on F with a weighting scheme of the form w-1
)
[σ2(Fo) + g|Fo| ], where σ2(Fo) is the variance in Fo due to counting statistics. R ) ∑||Fo| - |Fc||/∑|Fo|, R′ ) ∑w1/2||Fo| - |Fc||/∑w1/2|Fo|.
2
b
in vacuo gave red microcrystals of [Ru3(µ-H)(µ-σ:η5-7,8-
Me2-7,8-C2B9H8)(CO)7(PCy3)] (6) (0.125 g).
(CO)5(NHMe2)(η5-7,8-Me2-7,8-C2B9H9)] (10) (35 mg),
respectively, as orange-red solids. Analytically pure
crystals of 9 and 10 were obtained by crystallization
from CH2Cl2 solutions layered with petroleum ether.
Rea ction of [Ru 3(CO)8(η5-7,8-Me2-7,8-C2B9H9)] (2)
w ith P yr id in e. Compound 2 (0.21 g, 0.30 mmol) and
an excess of pyridine (72 µL, 0.89 mmol) in CH2Cl2 (30
mL) were stirred at room temperature for 2 h. Solvent
was removed in vacuo, and the residue was dissolved
in a minimum volume (ca. 5 mL) of CH2Cl2-petroleum
ether (1:1) and chromatographed. The polarity of the
eluting solvent CH2Cl2-petroleum ether was slowly
increased from 1:4 to 1:1. Two orange colored bands
developed. Elution of these fractions gave, after re-
moval of solvent in vacuo, the complexes [Ru2(CO)5-
(NC5H5)(η5-7,8-Me2-7,8-C2B9H9)] (11) (14 mg) and [Ru2-
(CO)4(NC5H5)2(η5-7,8-Me2-7,8-C2B9H9)] (12) (49 mg),
respectively, both isolated as orange-red microcrystals.
Analytically pure crystals of 11 and 12 were obtained
by crystallization from CH2Cl2 solutions layered with
petroleum ether.
(v) Compound 2 (0.22 g, 0.32 mmol) in CH2Cl2 (20 mL)
was treated with an excess of PMe3 (1 mL, 1.0 M THF
solution, 1 mmol) and the mixture stirred for 10 min at
room temperature. The volume of CH2Cl2 was reduced
to ca. 2 mL, and CH2Cl2-petroleum ether (20 mL, 1:4)
was added to give orange-red microcrystals of [Ru2(CO)4-
(PMe3)2(η5-7,8-Me2-7,8-C2B9H9)] (7) (0.13 g). Analytical
pure 7 was obtained by crystallization from CH2Cl2
solutions layered with petroleum ether.
(vi) A mixture of 2 (0.21 g, 0.31 mmol) and dppm (0.12
g, 0.31 mmol) was stirred at room temperature in THF
(30 mL) for 2 h. Solvent was removed in vacuo, and
the residue extracted with CH2Cl2-petroleum ether (50
mL, 1:4). A white precipitate was filtered off, and the
red filtrate was concentrated to ca. 20 mL. Red crystal-
line [Ru3(µ-dppm)(CO)6(η5-7,8-Me2-7,8-C2B9H9)] (8) (0.09
g) was obtained after storing the solution in a freezer
overnight.
Rea ction of [Ru 3(CO)8(η5-7,8-Me2-7,8-C2B9H9)] (2)
w it h N,N,N′,N′-t et r a m et h yld ia m in om et h a n e.
A
Cr ysta l Str u ctu r e Deter m in a tion s a n d Refin e-
m en ts. Crystal data and other experimental details for
5 and 9-11 are given in Table 8. Conoscopic examina-
tions (Zeiss Photomicroscope II) of the crystals studied
verified their biaxial nature and optical homogeneity,
prior to their being mounted on glass fibers and
transferred to the goniometer head on the diffractome-
ter. Final lattice parameters were determined by least-
squares refinement of 25 carefully centered high-angle
reflections. No significant variations were observed in
the periodic intensity measurements (2 h intervals) of
compounds 5 and 9. Hence, crystal stability and
electronic hardware reliability were established. How-
CH2Cl2 (30 mL) solution of 2 (0.20 g, 0.29 mmol) and
Me2NCH2NMe2 (40 µL, 0.29 mmol) was stirred at room
temperature overnight. Solvent was removed in vacuo
and the dark red residue dissolved in the minimum
volume of CH2Cl2-petroleum ether (2:3) and chromato-
graphed. Elution with CH2Cl2-petroleum ether (2:3)
removed a broad orange fraction, which was concen-
trated and applied to a TLC plate. On eluting with CH2-
Cl2-petroleum ether (3:7), two yellow bands developed
and were collected. After filtration and removal of
solvent in vacuo the yellow solutions gave [Ru2(µ-η5-7,8-
Me2-10-CH2NMe2-7,8-C2B9H8)(CO)5] (9) (7 mg) and [Ru2-

Carborane Complexes of Ruthenium
Organometallics, Vol. 15, No. 24, 1996 5111
ever, for complexes 10 and 11 decays of -0.10 and
-0.06% h-1, respectively, were corrected by employing
the SDP program Decay,11 which applied a linear decay
correction to the data sets (maximum corrections,
1.05356 and 1.02582, respectively). The monitored
check reflections of 5 and 9-11 were removed and the
averaging of duplicate and equivalent data in each data
set was carried out [Rint ) 0.210 (5), 0.027 (9), 0.023
(10), and 0.016 (11)]. The remaining data in each data
set were corrected for Lorentz, polarization, and X-ray
absorption effects. For compounds 5, 9, and 11 empiri-
cal absorption corrections were applied12 based on high-
angle ψ scans (transmission factors: minimum, 0.9395,
0.8715, 0.8618; maximum, 0.9995, 0.9985, 0.9971, re-
spectively). For compound 10 a numerical absorption
correction11 based on crystal face measurements was
used (transmission factor: minimum, 0.8490; maxi-
mum, 0.9377). A zero moment test (NZ-test)13 on the
observed data sets indicated that all were centrosym-
metric. Space group determinations were based on
systematic absences, and the presence of any additional
symmetry was ruled out by employing the MISSYM
program.14 Phase problems for the compounds studied
were solved by utilizing the heavy-atom Patterson
technique15 which located all Ru atoms. Standard
difference Fourier mapping yielded all other non-
hydrogen atoms. Boron hydrogen atoms and bridging
H atoms in 5 and 9-11 were located using the programs
BHGEN16 and XHYDEX,5 respectively. The boron H
atoms were fixed at a B-H distance of 1.10 Å (Uiso
)
60 × 10-3 Å2), and all carbon H atoms were idealized
and held constant (C-H, 0.96 Å; Uiso ) 80 × 10-3 Å2).
The models were refined using SHELXTL-PC pro-
grams,15 and after application of secondary extinction
corrections to each data set, anisotropic refinements of
all non-hydrogen atoms yielded respectable residual
indices. Final electron density maps revealed only
random fluctuating backgrounds. Atomic scattering
factors with related anomalous dispersion correction
factors were obtained from the usual source.17
Ack n ow led gm en t. We thank the Robert A. Welch
Foundation for support (Grants AA-1201 and -0668) and
Dr. Paul J elliss for helpful discussions.
Su p p or tin g In for m a tion Ava ila ble: Complete tables of
atomic coordinates, bond lengths and angles, anisotropic
thermal parameters, and hydrogen atom parameters and
ORTEP plots for 5 and 9-11 (34 pages). Ordering information
is given on any current masthead page.
(11) Enraf-Nonius VAX Structure Determination Package, Delft,
Holland, 1989.
(12) North, A. C. T.; Phillips, D. C.; Mathews, F. S. Acta Crystallogr.
1968, A24, 351.
(13) Howells, E. R.; Phillips, D. C.; Rogers, D. Acta Crystallogr. 1950,
3, 210.
OM9603629
(15) SHELXTL-PC, Siemens X-ray Instruments, Madison, WI, 1989.
(16) Sherwood, P. A program BHGEN for the calculation of idealized
hydrogen atom positions for a nido-icosahedral carbaborane fragment,
Bristol University, 1986.
(14) Gabe, E. J .; LePage, Y.; Charland, J .-P.; Lee, F. L. J . Appl.
Crystallogr. 1989, 22, 384.
(17) International Tables for X-ray Crystallography; Kynoch Press:
Birmingham, U.K., 1974; Vol. 4.