Studies with the ruthenacarborane complex [Ru(CO)(PPh3)(THF)(η5-7,8-C2B9H 11)]: Reactions with terminal alkynes

Article abstract of DOI:10.1021/om000018i

The syntheses of the complexes [Y][RuX(L)(PPh₃)(η⁵-7,8-C₂B ₂H₁₁)] (X = Cl, Y = K(18-crown-6), L = CO (1), PPh₃ (2); X = I, Y = NEt₄, L = CO (3)) are reported, and the structure of 3 has been established by an X-ray diffraction study. The anion adopts the piano stool structure with the ruthenium atom η⁵-coordinated on one side by a nido-7,8-C₂B₉H₁₁ group and on the other by the CO, PPh₃, and I ligands. Treatment of 1 with TlPF₆ in THF (tetrahydrofuran) affords solutions of the labile species [Ru(THF)(CO)(PPh₃)(η⁵-7,8-C₂B ₉H₁₁)] (5), which readily react with a 3-fold excess of the monosubstituted alkynes RC≡CH (R = Ph, Bu^t, SiMe₃). The product from PhC≡CH is [Ru(CO)(PPh₃)(η²: η⁵-9-(E)-C(H)=C(H)Ph-7,8-C₂B₉H ₁₀)] (8), the structure of which was determined by X-ray crystallography. The metal atom is η⁵-coordinated by the open face of the nido-7,8-C₂B₉ cage and also η²-coordinated by the C=C bond of the E-C(H)=C(H)Ph group, the latter being attached to a boron atom in an α-site with respect to the carbons of the CCBBB ring ligating the ruthenium. Reaction between 5 and Bu^tC≡CH gives [Ru(CO)(PPh₃)(η²: η⁵-9-(E)-C(H)=C(H)Bu^t-10-(E)-C(H)=C(H)-Bu ^t-7,8-C₂B₉H₉)] (9). The η² bonding mode of the 9-(E)-C(H)=C(H)Bu^t group to the metal is displaced in reactions with PMe₃, CNBu^t, and CO, yielding the species [Ru(CO)(PPh₃)(L)-(η⁵-9,10-{(E)-C(H)=C(H)Bu ^t}₂-7,8-C₂B₉H₉)] (L = PMe₃ (10), CNBu^t (11), CO (12)). The alkyne Me₃SiC=CH reacts with 5 in the presence of traces of moisture to give [Ru(CO)(PPh₃)(η²: η⁵-9-C(H)=CH₂-7,8-C₂B₉H ₁₀)] (13), having a molecular structure closely related to that of 8, as confirmed by an X-ray diffraction study. Compound 13 reacts with CNBu^t to afford [Ru(CO)(PPh₃)(CNBu^t)(η⁵-9-C(H)=CH ₂-7,8-C₂B₉H₁₀)] (14), studied by X-ray diffraction, and with PMe₃ to give the ylide complex [Ru(CO)(PPh₃)(σ: η⁵-9-C(H)(PMe₃)CH₂-7,8-C₂B ₉H₁₀)] (15). The NMR data (¹H, ¹³C{¹H}, ¹¹B{¹H}) are reported and discussed.

Full text of DOI:10.1021/om000018i

Organometallics 2000, 19, 1983-1992
1983
Stu d ies w ith th e Ru th en a ca r bor a n e Com p lex
[Ru (CO)(P P h 3)(THF )(η5-7,8-C2B9H11)]: Rea ction s w ith
Ter m in a l Alk yn es†
Shaowu Du, Dianne D. Ellis, Paul A. J elliss, J ason A. Kautz,
J ohn M. Malget, and F. Gordon A. Stone*
Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798-7348
Received J anuary 10, 2000
The syntheses of the complexes [Y][RuX(L)(PPh3)(η5-7,8-C2B9H11)] (X ) Cl, Y ) K(18-
crown-6), L ) CO (1), PPh3 (2); X ) I, Y ) NEt4, L ) CO (3)) are reported, and the structure
of 3 has been established by an X-ray diffraction study. The anion adopts the “piano stool”
structure with the ruthenium atom η5-coordinated on one side by a nido-7,8-C2B9H11 group
and on the other by the CO, PPh3, and I ligands. Treatment of 1 with TlPF6 in THF
(tetrahydrofuran) affords solutions of the labile species [Ru(THF)(CO)(PPh3)(η5-7,8-C2B9H11)]
(5), which readily react with a 3-fold excess of the monosubstituted alkynes RCtCH (R )
Ph, But, SiMe3). The product from PhCtCH is [Ru(CO)(PPh3)(η2: η5-9-(E)-C(H)dC(H)Ph-
7,8-C2B9H10)] (8), the structure of which was determined by X-ray crystallography. The metal
atom is η5-coordinated by the open face of the nido-7,8-C2B9 cage and also η2-coordinated by
the CdC bond of the E-C(H)dC(H)Ph group, the latter being attached to a boron atom in an
R-site with respect to the carbons of the CCBBB ring ligating the ruthenium. Reaction
between 5 and ButCtCH gives [Ru(CO)(PPh3)(η2: η5-9-(E)-C(H)dC(H)But-10-(E)-C(H)dC(H)-
But-7,8-C2B9H9)] (9). The η2 bonding mode of the 9-(E)-C(H)dC(H)But group to the metal is
displaced in reactions with PMe3, CNBut, and CO, yielding the species [Ru(CO)(PPh3)(L)-
(η5-9,10-{(E)-C(H)dC(H)But}2-7,8-C2B9H9)] (L ) PMe3 (10), CNBut (11), CO (12)). The alkyne
Me3SiCtCH reacts with 5 in the presence of traces of moisture to give [Ru(CO)(PPh3)(η2:
η5-9-C(H)dCH2-7,8-C2B9H10)] (13), having a molecular structure closely related to that of
8, as confirmed by an X-ray diffraction study. Compound 13 reacts with CNBut to afford
[Ru(CO)(PPh3)(CNBut)(η5-9-C(H)dCH2-7,8-C2B9H10)] (14), studied by X-ray diffraction, and
with PMe3 to give the ylide complex [Ru(CO)(PPh3)(σ: η5-9-C(H)(PMe3)CH2-7,8-C2B9H10)] (15).
The NMR data (1H, 13C{1H}, 11B{1H}) are reported and discussed.
In tr od u ction
alkynes RCtCH, leading to replacement of BH cage
vertexes with BC(H)dC(H)R groups,2b and reactions
with metal-ligand fragments, affording bimetal com-
plexes with exopolyhedral B-HFM bonds.2a,c,e Replace-
ment of CO groups by phosphine ligands on the ruthe-
nium in molecules with a closo-3,1,2-RuC2B9 core
structure would be expected to influence the nature of
products obtained by increasing electron density at the
metal center. For this reason we have undertaken the
examination of the chemistry of species containing Ru-
(PPh3)(η5-7,8-C2B9H11) fragments.
We recently described a high-yield synthesis of the
salt [K(18-crown-6)][RuH(PPh3)2(η5-7,8-C2B9H11)] and
showed it to be a useful precursor to several new
ruthenacarborane complexes.1 In this paper we describe
further studies on ruthenacarboranes having Ru(PPh3)-
(η5-7,8-C2B9H11) fragments. Molecules in which a ru-
thenium atom is part of a closo-3,1,2-RuC2B9 cage
framework and where the metal also carries exopoly-
hedral ligands are of interest, because not only do they
have counterparts in cyclopentadienide chemistry but
they also undergo a variety of reactions involving both
the associated ligands and the cage system.2 Thus, the
complex [Ru(CO)3(η5-7,8-C2B9H11)],2a isolobal with [Ru-
(CO)3(η5-C5H5)]+ or [Mn(CO)3(η5-C5H5)], provides a route
to many other species. These include reactions with
Resu lts a n d Discu ssion
Treatment of Et2O solutions of the salts [K(18-crown-
6)][RuH(L)(PPh3)(η5-7,8-C2B9H11)] (L ) CO, PPh3)1 with
HCl affords the complexes [K(18-crown-6)][RuCl(L)-
† The compounds described in this paper have a ruthenium atom
incorporated into a closo-1,2-dicarba-3-ruthenadodecaborane frame-
work. However, to avoid a complicated nomenclature for the complexes
reported, and to relate them to the many known ruthenium species
with η5-coordinated cyclopentadienyl ligands, we treat the cages as
nido 11-vertex ligands with numbering as for an icosahedron from
which the 12th vertex has been removed.
(2) (a) Anderson, S.; Mullica, D. F.; Sappenfield, E. L.; Stone, F. G.
A. Organometallics 1995, 14, 3516. (b) Anderson, S.; Mullica, D. F.;
Sappenfield, E. L.; Stone, F. G. A. Organometallics 1996, 15, 1676. (c)
Anderson, S.; J effery, J . C.; Liao, Y.-H.; Mullica, D. F.; Sappenfield,
E. L.; Stone, F. G. A. Organometallics 1997, 16, 958. (d) J effery, J . C.;
J elliss, P. A.; Psillakis, E.; Rudd, G. E. A.; Stone, F. G. A. J . Organomet.
Chem. 1998, 562, 17. (e) J effery, J . C.; J elliss, P. A.; Rudd, G. E. A.;
Sakanishi, S.; Stone, F. G. A.; Whitehead, J . J . Organomet. Chem.
1999, 582, 90.
(1) Ellis, D. D.; Couchman, S. M.; J effery, J . C.; Malget, J . M.; Stone,
F. G. A. Inorg. Chem. 1999, 38, 2981.
10.1021/om000018i CCC: $19.00 © 2000 American Chemical Society
Publication on Web 04/19/2000

1984 Organometallics, Vol. 19, No. 10, 2000
Ta ble 1. An a lytica l a n d P h ysica l Da ta
Du et al.
anal. (%)b
yield
(%)
ν
max(CO)/
compd
color
ν
max(NC)*a (cm-1
)
C
H
[K(18-crown-6)][RuCl(CO)(PPh3)(η5-7,8-C2B9H11)] (1)
[K(18-crown-6)][RuCl(PPh3)2(η5-7,8-C2B9H11)] (2)
[NEt4][RuI(CO)(PPh3)(η5-7,8-C2B9H11)] (3)
orange 90 1942 s
45.8 (46.0) 5.8 (5.8)
53.7 (54.8) 6.0 (6.0)
43.1 (43.0) 5.8 (5.8)c,d
49.3 (49.0) 5.7 (5.6)c,e
54.7 (55.6) 5.2 (5.1)f
57.3 (57.6) 6.7 (6.7)
56.3 (56.6) 7.3 (7.2)
59.3 (59.2) 7.3 (7.1)g
57.5 (57.0) 6.6 (6.4)
50.3 (50.2) 5.1 (5.1)
49.0 (48.5) 5.5 (5.4)h,i
49.7 (49.9) 6.0 (5.9)
red
76
red
yellow
92 1940 s
95 2166 s*, 1987 s
[Ru(CNBut)(CO)(PPh3)(η5-7,8-C2B9H11)] (4)
[Ru(CO)(PPh3){η2:η5-9-(E)-C(H)dC(H)Ph-7,8-C2B9H10}] (8)
orange 77 1972 s
[Ru(CO)(PPh3){η2:η5-9-(E)-C(H)dC(H)But-10-(E)-C(H)dC(H)But-7,8-C2B9H9}] (9) red
64 1963 s
[Ru(CO)(PMe3)(PPh3)(η5-9,10-{(E)-C(H)dC(H)But}2-7,8-C2B9H9)] (10)
[Ru(CNBut)(CO)(PPh3)(η5-9,10-{(E)-C(H)dC(H)But}2-7,8-C2B9H9)] (11)
[Ru(CO)2((PPh3)(η5-9,10-{(E)-C(H)dC(H)But}2-7,8-C2B9H9)] (12)
[Ru(CO)(PPh3){η2:η5-9-C(H)dCH2-7,8-C2B9H10}] (13)
yellow
86 1959 s
yellow
yellow
yellow
yellow
yellow
84 2155 s*, 1987 s
83 2002 s, 2049 s
90 1973 s
[Ru(CO)(PPh3)(CNBut){η5-9-C(H)dCH2-7,8-C2B9H10}] (14)
[Ru(CO)(PPh3){σ:η5-9-C(H)(PMe3)CH2-7,8-C2B9H10}] (15)
81 2160 s*, 1988 s
88 1906 sj
a
Measured in CH2Cl2. A medium-intensity band observed at ca. 2550 cm-1 in the spectra of all compounds is due to B-H absorptions.
Calculated values are given in parentheses. c Crystallizes with half a molecule of CH2Cl2. N 1.7 (1.7). e N 2.2 (2.2). f EI mass spectrum:
b
d
m/z 625.96 ([8]+) (calcd 625.26); 597.98 ([8]+ - CO). N 1.9 (1.8). Crystallizes with a molecule of CH2Cl2. N 2.0 (2.0). Measured in
g
h
i
j
Me2CO.
Ch a r t 1
(PPh3)(η5-7,8-C2B9H11)] (L ) CO (1), PPh3 (2); Chart 1)
in yields which are essentially quantitative. The related
iodo compound [NEt4][RuI(CO)(PPh3)(η5-7,8-C2B9H11)]
(3) was prepared from the reaction between [Ru(CO)-
F igu r e 1. Structure of the anion of [NEt4][RuI(CO)(PPh3)-
(PPh3)2(η5-7,8-C2B9H11)] and [NEt4]I in THF (tetrahy-
(η5-7,8-C2B9H11)] (3), showing the crystallographic labeling
drofuran). The three compounds were characterized by
the data given in Tables 1-3, but to place the structures
of these species on a firm basis, that of 3 was established
scheme. Hydrogen atoms are omitted for clarity, and
thermal ellipsoids are shown at the 40% probability level.
by a single-crystal X-ray diffraction study. The anion is
shown in Figure 1 and is structurally akin to [RuCl-
(CO)2(η5-7,8-C2B9H11)]-.2a Selected structural param-
eters are listed in Table 4. The anion adopts the “piano
stool” structure with the ruthenium atom η5-coordinated
on one side by a nido-7,8-C2B9H11 group and on the
other by the CO, PPh3, and I ligands (C-Ru-P ) 91.1-
(2)°, P-Ru-I ) 89.92(3)°, C-Ru-I ) 92.4(2)°).
During the course of our studies it was observed that
heating [Ru(CO)(PPh3)2(η5-7,8-C2B9H11)] with CNBut in
CH2Cl2 gave the complex [Ru(CNBut)(CO)(PPh3)(η5-7,8-
C2B9H11)] (4) by displacement of a PPh3 group rather
than a CO molecule from the ruthenium reactant.1 This
might be expected on both steric and electronic grounds.
Data for 4 are reported in Tables 1-3. This is an early
example of a molecule containing the target Ru(CO)-
(PPh3)(η5-7,8-C2B9H11) fragment. However, the synthe-
sis of the starting material, [Ru(CO)(PPh3)2(η5-7,8-
C2B9H11)], necessitated an awkward synthetic procedure.
Moreover our work established that the salt 1 was a
more convenient precursor to new complexes.
The presence of the labile THF molecule in the
complex [Ru(CO)2(THF)(η5-7,8-C2B9H11)]2a makes it a
very versatile synthon. Hence, it was of interest to
establish whether the corresponding THF adduct could
be derived from the species 1 when dissolved in THF,
using TlPF6 to remove halide. Although the desired
species [Ru(CO)(PPh3)(THF)(η5-7,8-C2B9H11)] (5) could
not be isolated, spectroscopic studies on the yellow
solutions formed in situ provided evidence for its forma-
tion. Thus, the solutions displayed in the IR a single
CO absorption at νmax 1964 cm-1. The 11B{1H} NMR
spectrum of 5 displays the expected nine signals, and
the 31P{1H} NMR spectrum, measured in CD2Cl2 with
a small amount of added THF, revealed a singlet at δ
48.0. The 31P{1H} NMR resonance for 1 is at δ 49.4, and
that for 4 is at δ 46.5. When THF-d8 was added to
solutions of 5, a second resonance slowly appeared at δ

Ruthenacarborane-Terminal Alkyne Reactions
Organometallics, Vol. 19, No. 10, 2000 1985
Ta ble 2. Hyd r ogen -1 a n d Ca r bon -13 NMR Da ta a
1H/δb
13C/δc
1
2
3
1.89, 3.58 (br s × 2, 2 H, cage CH), 3.61 (m, 24 H, OCH2),
203.5 (d, CO, J (PC) ) 21), 134.7-128.0 (Ph),
7.26-7.74 (m, 15 H, Ph)
70.6 (OCH2), 59.7, 41.3 (cage CH)
2.92 (br s, 2 H, cage CH), 3.58 (m, 24 H, OCH2), 6.90-7.80
(m, 30 H, Ph)
139.1-126.8 (Ph), 70.5 (OCH2), 45.7 (cage CH)
1.31 (t, 12 H, CH2Me, J (HH) ) 9), 1.65 (br s, 1 H, cage CH),
3.19 (q, 8 H, CH2Me, J (HH) ) 9), 4.11 (br s, 1 H, cage CH),
7.33-7.71 (m, 15 H, Ph)
204.8 (d, CO, J (PC) ) 20), 134.6-127.8 (Ph),
53.2 (CH2Me), 53.1, 38.7 (cage CH), 7.9 (CH2Me)
4
8
1.26 (s, 9 H, But), 2.05, 2.15 (br s × 2, 2 H, cage CH),
200.1 (d, CO, J (PC) ) 15), 144.2 (br, CNBut), 133.6-129.3 (Ph),
58.8 (CMe3), 46.0, 43.4 (cage CH), 30.3 (CMe3)
198.6 (d, CO, J (PC) ) 20), 139.2-126.3 (Ph), 82.0 (br, dCHB),
81.0 (dCHPh), 61.3, 37.8 (cage CH)
7.46-7.49 (m, 15 H, Ph)
0.70, 3.09 (br s × 2, 2 H, cage CH), 3.89 (d of d, 1 H, dCHPh,
J (HH) ) 13, J (PH) ) 5), 5.16 (d, 1 H, dCHB,
J (HH) ) 13), 6.92-7.42 (m, 20 H, Ph)
9
-0.25 (br s, 1 H, cage CH), 0.83, 1.02 (s × 2, 18 H, But), 2.95
(br s, 1 H, cage CH),d 4.06 (br s, 1 H, dCHB),d 4.76 (d, 1 H,
dCHBut, J (HH) ) 14), 5.67, 5.95 (d × 2, 2 H, dCHB and
dCHBut, J (HH) ) 18, 18], 7.42-7.63 (m, 15 H, Ph)
201.1 (d, CO, J (PC) ) 18), 147.3,d 133.3 (dCHBut),
131.1-129.2 (Ph), 105.2,d 87.3 (br, dCHB), 58.1, 35.3 (br,
cage CH), 34.7, 34.2 (CMe3), 31.5, 29.7 (CMe3)
10 0.98, 1.10 (s × 2, 18 H, But), 1.22 (d, 9 H, PMe3, J (PH) ) 9), 3.35, 204.6 (d of d, CO, J (PC) ) 16, 19), 149.4, 147.6 (dCHBut),
3.33 (br s × 2, 2 H, cage CH), 5.65, 5.77, 5.85, 6.32 (d × 4,
4 H, dCHBut × 2 and dCHB × 2, J (HH) ) 17, 17, 17, 17),
7.39-7.59 (m, 15 H, Ph)
135.1, 134.6 (br, dCHB), 134.1-128.6 (Ph),
51.3 (cage CH), 36.5, 34.3 (CMe3), 30.8 (cage CH), 30.0,
29.6 (CMe3), 19.2 (d, MeP, J (PC) ) 30)
11 1.03, 1.07, 1.20 (s × 3, 27 H, But), 1.42, 3.32 (br s × 2, 2 H,
cage CH), 5.66, 5.72, 5.73, 6.09 (d × 4, 4 H, dCHBut × 2 and
dCHB × 2, J (HH) ) 18, 18, 18, 18), 7.43-7.59 (m, 15 H, Ph)
202.5 (d, CO, J (PC) ) 16), 146.3, 146.0 (dCHBut), 145.0
(br, CNBut), 133.7-128.9 (Ph), 131.8 (br, dCHB),
127.6 (br, dCHB), 58.5, 51.3 (cage CH), 51.2 (NCMe3),
39.6, 34.1 (CMe3), 30.2, 30.1, 29.8 (CMe3)
12 0.97, 1.02 (s × 2, 18 H, But), 1.93, 2.37 (br s × 2, 2 H, cage
CH), 5.56, 5.74, 5.76, 5.83 (d × 4, 4 H, dCHBut × 2, and
dCHB × 2, J (HH) ) 18, 18, 18, 18), 7.49-7.56 (m, 15 H, Ph)
13 0.18 (br s, 1 H, cage CH), 2.05 (d of d, 1 H, dCHbHc,
J (HaHc) ) 13, J (PH) ) 6), 3.05 (br s, 1 H, cage CH), 3.70
(d, 1 H, dCHbHc, J (HaHb) ) 9), 4.71 (d of d, 1 H, dCHaB,
J (HcHa) ) 13, J (HbHa) ) 9), 7.46-7.56 (m, 15 H, Ph)
198.4, 196.0 (d × 2, CO, J (PC) ) 15, 15), 147.7, 146.4
(dCHBut), 133.3-128.7 (Ph),e 128.8 (vbr, dCHB), 47.1,
45.8 (cage CH), 34.1, 29.3 (CMe3), 29.9, 29.2 (CMe3)
198.4 (d, CO, J (PC) ) 20), 133.4-129.2 (Ph), 81.9 (br, dCHB),
60.7 (d, dCH2, J (PC) ) 3), 60.2, 39.7 (cage CH)
14 1.19 (s, 9 H, But), 1.61, 3.42 (br s × 2, 2 H, cage CH), 5.10 (d of d, 201.9 (d, CO, J (PC) ) 16), 145.7 (br, dCHB), 143.8
1 H, dCHbHc, J (HaHb) ) 13, J (HcHb) ) 4), 5.16 (d of d, 1 H,
dCHbHc, J (HaHc) ) 19, J (HbHc) ) 4), 6.17 (d of d, 1 H, dCHaB,
J (HcHa) ) 19, J (HbHa) ) 13), 7.45-7.56 (m, 15 H, Ph)
15f 0.40 (br s, 1 H, cage CH), 1.18 (d of d, 1 H, CHbHc,
J (HaHb) ) 9, J (PH) ) 9), 1.33 (d, 9 H, Me, J (PH) ) 14),
1.53 (d, 1 H, CHbHc, J (HaHc) ) 15), 2.18 (d of d of d,
1 H, CHaBP, J (HcHa) ) 15, J (HbHa) ) 9, J (PH) ) 9),
2.39 (br s, 1 H, cage CH), 7.45-7.53 (m, 15 H, Ph)
a
(CNBut), 133.7-128.9 (Ph), 118.4 (dCH2), 58.5 (CMe3),
51.5 (d, cage CH, J (PC) ) 9), 41.5 (cage CH), 30.1 (CMe3)
206.5 (d, CO, J (PC) ) 20), 134.7-128.4 (Ph), 47.2, 30.4
(cage CH), 22.7 (br, CHB), 18.1 (CH2), 5.9 (d, PMe3,
J (PC) ) 53)
Units and conditions: chemical shifts (δ) in ppm; coupling constants (J ) in Hz; measurements in CD2Cl2 as solvent, unless otherwise
stated. b Resonances for terminal B-H protons occur as broad unresolved signals in the range ca. -2 to 3. c Hydrogen-1 decoupled; chemical
d
shifts are positive to high frequency of SiMe4. Signals assigned to η2-C(H)dC(H)But group ligating the Ru atom. e Two separate signals
expected; peaks not resolved due to proximity and broadness. f Recorded in (CD3)2SO due to insolubility of the complex.
47.4 which increased in intensity upon further addition
of deuterated solvent. This suggests a facile exchange
between THF and THF-d8 at the ruthenium center.
We have previously reported reactions between [Ru-
(CO)2(THF)(η5-7,8-C2B9H11)] and alkenes and alkynes
(RCtCH and RCtCR′, R, R′ ) alkyl, aryl).2b,d Alkenes,
as well as internal alkynes of the type RCtCR′, afford
stable η2 complexes of formulation [Ru(CO)2(alkene or
alkyne)(η5-7,8-C2B9H11)]. However, terminal alkynes,
RCtCH, give ruthenium-cage substitution products
with η2-(E)-BC(H)dC(H)R groups; e.g., in a reaction
between [Ru(CO)2(THF)(η5-7,8-C2B9H11)] and an excess
of ButCtCH the compound [Ru(CO)2(η2:η5-9-(E)-C(H)d
C(H)But-10,11-{(E)-C(H)dC(H)But}2-7,8-C2B9H8)] (6;
Chart 2) was formed. We were prompted by these
results to investigate reactions of 5 with both alkenes
and alkynes. For these experiments 5 was generated
from 1 as described above and used in situ because of
its lability.
complex [Ru(CO)2(Me3SiCHdCH2)(η5-7,8-C2B9H11)],2b
the alkene did not react with THF solutions of 5.
However, bubbling C2H4 through THF solutions yielded,
after separation by column chromatography, an un-
stable yellow solid identified spectroscopically as [Ru-
(CO)(PPh3)(C2H4)(η5-7,8-C2B9H11)] (7). The IR spectrum
showed a single CO stretch at 1991 cm-1, to be com-
pared with that observed at 1964 cm-1 in the solutions
of 5. The coordinated C2H4 molecule was revealed in the
1H NMR spectrum by a multiplet at δ ca. 3.22 and in
the 13C{1H} NMR spectrum by a doublet at δ 61.0 (J (PC)
) 13 Hz). The corresponding signals in the spectra of
[Ru(CO)2(C2H4)(η5-7,8-C2B9H11)] are seen at δ 3.80 (1H)
and 64.6 (13C).2b The 31P{1H} NMR spectrum of 7 shows
a singlet peak at δ 54.4. It is evident from these studies
that the fragment Ru(CO)(PPh3)(η5-7,8-C2B9H11) bonds
alkenes less tightly than does Ru(CO)2(η5-7,8-C2B9H11),
perhaps due to reduced electrophilicity at the Ru center
when CO is replaced by PPh3. Similar behavior was
observed in reactions with alkynes RCtCR. Thus,
whereas it was possible to isolate the stable compound
In contrast with [Ru(CO)2(THF)(η5-7,8-C2B9H11)], which
upon treatment with Me3SiCHdCH2 afforded the stable

1986 Organometallics, Vol. 19, No. 10, 2000
Ta ble 3. Bor on -11 a n d P h osp h or u s-31 NMR Da ta a
Du et al.
11B/δb
31P/δc
1
2
3
4
8
9
-2.2 (1 B), -6.6 (2 B), -9.6 (1 B), -12.6 (1 B), -16.0 (1 B), -19.5 (1 B), -21.9 (1 B), -25.7 (1 B)
-2.2 (1 B), -6.3 (2 B), -10.5 (1 B), -13.4 (3 B), -26.1 (2 B)
49.4
38.5
51.1
46.5
40.0
41.3
-1.4 (1 B), -6.5 (3 B), -13.8 (1 B), -15.9 (1 B), -18.4 (1 B), -22.4 (1 B), -24.5 (1 B)
0.5 (1 B), -5.5 (1 B), -7.7 (1 B), -8.6 (1 B), -9.8 (2 B), -21.1 (3 B)
7.9 (1 B), 6.6 (1 B), 1.6 (2 B), -14.0 (1 B), -15.6 (1 B), -18.6 (1 B), -21.6 (2 B)
16.0 (1 B, B-C), 8.3 (1 B, B-C), 3.6 (1 B), 1.3 (1 B), -13.5 (1 B), -15.8 (1 B),
-19.6 (1 B), -23.4 (2 B)
9.3 (1 B, B-C), 0.0 (1 B), -1.8 (1 B), -4.8 (1 B, B-C), -9.0 (1 B), -11.9 (1 B),
-18.5 (2 B), -26.2 (1 B)
10
46.6 (d, PPh3, J (PP) ) 31),
-9.7 (d, PMe3, J (PP) ) 31)
11
12
13
14
8.7 (1 B, B-C), -1.3 (1 B), -2.7 (2 B), -10.2 (2 B), -17.5 (1 B), -19.6 (1 B), -25.0 (1 B)
7.6 (1 B, B-C), 2.5 (2 B), -4.5 (2 B), -9.1 (1 B), -16.1 (1 B), -20.3 (1 B), -24.0 (1 B)
9.2 (1 B, B-C), 6.3 (1 B), 1.2 (2 B), -13.1 (1 B), -15.2 (1 B), -19.2 (1 B), -21.4 (2 B)
0.1 (1 B), -2.1 (1 B),d-4.5 (2 B, B-C), -9.4 (1 B), -11.7 (1 B), -17.6 (1 B),
-19.1 (1 B), -22.7 (1 B)
47.3
41.4
46.3
50.9
15e
-6.5 (3 B), -9.5 (2 B), -12.4 (2 B), -21.0 (1 B), -25.1 (1 B)
50.9 (PPh3), 24.2 (PMe3)
a
b
Units and conditions: chemical shifts (δ) in ppm; coupling constants (J ) in Hz; measurements in CD2Cl2 as solvent. Hydrogen-1
decoupled; chemical shifts are positive to high frequency of BF3‚Et2O (external). Peaks due to B-C boron nuclei were identified as singlets
in the fully coupled 11B NMR spectrum. Those in complexes 8 and 15, and one each in 11 and 12, could not be unambiguously assigned.
c Hydrogen-1 decoupled; chemical shifts are positive to high frequency of H3PO4 (external). Single B-C boron resonance overlaps with
d
a B-H boron signal. e Recorded in (CD3)2SO.
Ta ble 4. Selected In ter n u clea r Dista n ces (Å) a n d An gles (d eg) for
[NEt4][Ru I(CO)(P P h 3)(η5-7,8-C2B9H11)]‚CH2Cl2 (3)
Ru-P
Ru-C(1)
P-C(41)
2.3243(12)
2.246(5)
1.842(5)
Ru-I
Ru-C(2)
P-C(21)
2.7574(6)
2.246(5)
1.836(4)
Ru-B(4)
Ru-B(5)
P-C(31)
2.267(5)
2.290(6)
1.843(5)
Ru-C
Ru-B(3)
C-O
1.842(6)
2.219(6)
1.142(6)
C-Ru-P
91.1(2)
C-Ru-I
92.4(2)
O-C-Ru
174.1(5)
P-Ru-I
89.92(3)
Ch a r t 2
dence rests on the appearance of a CO band in the IR
spectrum at 1989 cm-1 and a resonance in the 31P{1H}
NMR spectrum at δ 42.6. Removal of MeCtCMe from
the solutions or chromatography of the mixture resulted
in decomposition.
Although 5 displayed little propensity to react with
disubstituted alkynes RCtCR, monosubstituted alkynes
RCtCH readily reacted. Thus, [Ru(CO)(PPh3)(η2: η5-9-
(E)-C(H)dC(H)Ph-7,8-C2B9H10)] (8) was obtained when
a 3-fold excess of PhCtCH was employed in reactions
with 1 in THF to which TlPF6 had been added. Data
for 8 are summarized in Tables 1-3. An X-ray crystal-
lographic analysis was carried out to establish the
structure fully, since NMR data alone (vide infra) could
not conclusively determine to which boron atom in the
CCBBB ring the η2-(E)-C(H)dC(H)Ph fragment was
attached. The results are summarized in Table 5, and
the molecule is shown in Figure 2. The ruthenium atom
is η5-coordinated by the open face of the nido-7,8-C2B9
cage, as expected. However, the metal atom is also η2-
coordinated by a CdC bond of the trans-BC(H)dC(H)-
Ph group which is attached to a boron atom lying in an
R-site with respect to the carbons of the CCBBB ring
ligating the ruthenium. The structure has a strong
resemblance to that of [Ru(CO)2(η2:η5-9-(E)-C(H)dC(H)-
But-7,8-C2B9H10)] obtained from [Ru(CO)2(THF)(η5-7,8-
C2B9H11)] and ButCtCH when 1 equiv of the alkyne is
used for reaction.2b However, as mentioned above and
further discussed below, when 3 equiv of ButCtCH is
employed in the reaction with [Ru(CO)2(THF)(η5-7,8-
C2B9H11)], the product is exclusively 6. In the molecule
8 the C(4)-C(5) (1.404(5) Å), Ru-C(4) (2.221(4) Å), Ru-
C(5) (2.397(4) Å), and Ru-B(3) (2.144(4) Å) distances
are essentially the same as those of the corresponding
connectivities in [Ru(CO)2(η2:η5-9-(E)-C(H)dC(H)But-
7,8-C2B9H10)] (1.398(7), 2.249(6), 2.401(5), and 2.152(6)
[Ru(CO)2(MeCtCMe)(η5-7,8-C2B9H11)],2b the related spe-
cies [Ru(CO)(PPh3)(MeCtCMe)(η5-7,8-C2B9H11)] ap-
pears to have only a fleeting existence. Only when 5 was
treated with a 10-fold excess of MeCtCMe, and when
CH2Cl2 was used as solvent instead of THF, was there
any evidence for the formation of the but-2-yne complex
[Ru(CO)(PPh3)(MeCtCMe)(η5-7,8-C2B9H11)]. This evi-

Ruthenacarborane-Terminal Alkyne Reactions
Organometallics, Vol. 19, No. 10, 2000 1987
Ta ble 5. Selected In ter n u clea r Dista n ces (Å) a n d An gles (d eg) for
[Ru (CO)(P P h 3){η2:η5-9-(E)-C(H)dC(H)P h -7,8-C2B9H10}] (8)
Ru-C(3)
Ru-C(1)
Ru-C(5)
C(5)-C(41)
1.844(4)
2.277(4)
2.397(4)
1.467(5)
Ru-B(3)
Ru-B(4)
B(3)-C(4)
2.144(4)
2.296(4)
1.510(6)
Ru-C(4)
Ru-B(5)
C(3)-O(3)
2.221(4)
2.319(4)
1.143(4)
Ru-C(2)
Ru-P
C(4)-C(5)
2.227(3)
2.3746(10)
1.404(5)
C(3)-Ru-B(3)
C(3)-Ru-C(2)
C(4)-Ru-C(1)
C(3)-Ru-B(5)
C(4)-Ru-P
123.5(2)
166.50(14)
114.6(2)
94.4(2)
125.28(10)
O(3)-C(3)-Ru
C(4)-C(5)-Ru
C(3)-Ru-C(4)
C(4)-Ru-C(2)
C(3)-Ru-B(4)
175.4(3)
C(4)-Ru-B(5)
C(3)-Ru-C(5)
C(5)-C(4)-B(3)
C(41)-C(5)-Ru
B(3)-Ru-C(4)
116.6(2)
C(3)-Ru-C(1)
C(4)-Ru-B(4)
C(3)-Ru-P
132.9(2)
73.7(2)
89.03(12)
90.14(9)
79.3(2)
65.6(2)
102.2(2)
76.24(14)
87.7(2)
104.5(2)
123.9(4)
126.6(2)
40.4(2)
P-Ru-C(5)
C(5)-C(4)-Ru
B-C boron nucleus, due to apparent overlap with
another signal. However this R-boron is likely to reso-
nate at δ 1.6, because the remaining signals (Table 3)
all appear as doublets in the fully coupled 11B NMR
spectrum and because these resonances usually appear
toward the low-field end of the spectrum.3
The reaction between 1 and a 3-fold excess of ButCt
CH in THF at room temperature, in the presence of
TlPF6, was next investigated. Column chromatography
of the mixture afforded the complex [Ru(CO)(PPh3)-
(η2: η5-9-(E)-C(H)dC(H)But-10-(E)-C(H)dC(H)But-7,8-
C2B9H9)] (9), identified by the data listed in Tables 1-3.
To establish the site of attachment of the C(H)dC(H)-
But groups to the cage borons, a single-crystal X-ray
diffraction study was undertaken. The crystals were
small and poorly diffracting, precluding a satisfactory
analysis; hence, the results are provided in the Sup-
porting Information. Nevertheless, the data could be
analyzed sufficiently to establish firmly that one C(H)d
C(H)But group is linked to a boron lying in an R-site in
the CCBBB ring with this alkenyl group η2-bonded to
the ruthenium atom, while a second C(H)dC(H)But
group is bonded to a cage boron which is at a â-site and
is pendant.
F igu r e 2. Structure of [Ru(CO)(PPh3)(η2: η5-9-(E)-C(H)d
C(H)Ph-7,8-C2B9H10)] (8), showing the crystallographic
labeling scheme. Except for H(4a) and H(5a), hydrogen
atoms are omitted for clarity, and thermal ellipsoids are
shown at the 40% probability level.
The presence of the two trans-C(H)dC(H)But protons
1
in 9 is evident from the H NMR spectrum (Table 2),
with the display of two pairs of signals at δ 4.06 and
4.76 and at δ 5.67 and 5.95. Since the former pair are
at higher field, they are assigned to the C(H)dC(H)But
moiety coordinated to the ruthenium atom.2b The signal
at δ 4.06 actually appears as a very broad signal, likely
due to the nearby quadrupolar boron nucleus. To
confirm that this was indeed due to the dCHB proton,
Å). Interestingly, the formation of [Ru(CO)2(η2:η5-9-(E)-
C(H)dC(H)But-7,8-C2B9H10)] is accompanied by that of
its isomer [Ru(CO)2(η2:η5-10-(E)-C(H)dC(H)But-7,8-
C2B9H10)], as revealed by NMR spectroscopy.2b In
contrast with the reaction of 5 with PhCtCH, we found
no evidence for an isomer of 8 with the η2-(E)-C(H)d
C(H)Ph group attached to the â-boron (or 10-position)
a
1H-1H COSY NMR spectrum (Figure 3) was mea-
sured. An off-diagonal correlation with the resonance
at δ 4.76 satisfies this assignment, and a correlation
between the doublets at δ 5.67 and 5.95 is also clearly
evident. Diagnostic peaks for the carbons of the C(H)d
C(H)But groups are seen in the 13C{1H} NMR spectrum
at δ 147.3 and 133.3 and at δ 105.2 and 87.3. The last
two resonances are characteristically broad, as is usual
for carbon nuclei attached to boron atoms.3 Resonances
in the CCBBB coordinating face.
The NMR data for 8 are in agreement with the results
of the X-ray diffraction study. Because of the high
degree of asymmetry of the nido-7,8-C2B9 framework
there are two widely separated resonances in the 1H and
in the 13C{1H} NMR spectra (Table 2) for the cage CH
groups (1H, δ 0.70 and 3.09; 13C{1H}, δ 37.8 and 61.3).
The signals for the protons of the η2-9-(E)-C(H)dC(H)-
1
for the cage CH groups are observed in both the H (δ
-0.25 and 2.95) and 13C{1H} (δ 58.1 and 35.3) NMR
spectra, the widely disparate chemical shifts being
indicative of the degree of asymmetry of the nido-9,10-
{C(H)dC(H)But}2-7,8-C2B9H9 framework in addition to
the chirality at ruthenium. The 11B{1H} NMR spectrum
(Table 3) shows eight signals, one peak being broad and
corresponding in intensity to two boron nuclei. The
1
Ph group display a H-1H coupling of 13 Hz, this value
being in accord with their transoid arrangement. The
signal at δ 3.89 shows a small doublet coupling of 5 Hz.
This was shown to be due to the 31P nucleus of the
1
coordinated phosphine ligand, as it disappeared in a H-
{31P} spectrum. In the 11B{1H} and 11B NMR spectra,
(3) Brew, S. A.; Stone, F. G. A. Adv. Organomet. Chem. 1993, 35,
a peak could not be unambiguously accredited to the
135,

1988 Organometallics, Vol. 19, No. 10, 2000
Du et al.
{1H} NMR spectra (Table 2) show the expected reso-
nances for the two trans-BC(H)dC(H)But groups in
different environments, except in the case of the 13C-
{1H} spectrum of 12 only one very broad dCHB peak
is seen, due to the proximity of two signals and nearness
of 11B nuclei. For 10 the 11B{1H} NMR spectrum was
well-resolved, leading to an unambiguous assignment
of the two resonances for the dCHB nuclei from a fully
coupled 11B spectrum. However, for 11 and 12 only one
of each pair of these 11B signals could be identified
(Table 3).
Earlier we reported that the reaction between Me3-
SiCtCH and [Ru(CO)2(THF)(η5-7,8-C2B9H11)] yielded a
mixture of isomers of the complexes [Ru(CO)2(η2:η5-n-
(E)-C(H)dC(H)SiMe3-7,8-C2B9H10] and [Ru(CO)2(η2:η5-
n-C(H)dCH2-7,8-C2B9H10] (n ) 9, 10). In this mixture
the isomers resulting from cleavage of SiMe3 groups
largely predominated.2b It was therefore of interest to
investigate the corresponding reaction between 5 and
Me3SiCtCH. The product isolated was [Ru(CO)(PPh3)-
(η2: η5-9-C(H)dCH2-7,8-C2B9H10)] (13), formed as a single
isomer. Evidently facile cleavage of the Me3Si group
occurred as in the reaction of the alkyne with [Ru(CO)2-
(THF)(η5-7,8-C2B9H11)], though the reaction of 5 is more
regioselective with respect to substitution by the organic
F igu r e 3. 360.13 MHz 1H-1H COSY NMR spectrum of
compound 9.
fragment on the CCBBB face.
resonances at δ 8.3 and 16.0 may be ascribed to the BC-
(H)dC(H)But nuclei, on the basis of their chemical shift
and their appearance as singlets in a fully coupled 11B
spectrum.3
Although it was apparent from the limited number
of peaks in the NMR spectra of complex 13 that it was
formed as a single isomer, an X-ray diffraction study
was carried out to establish the precise position of
attachment of the vinyl group to the cage. The results
confirmed that the isomer formed was indeed the
9-C(H)dCH2-7,8-C2B9H10 species. However, the X-ray
data were so similar to those of 8 that they are included
in the Supplementary Information. Peaks in the NMR
In the reaction between 5 and ButCtCH there was
no evidence for formation of a product with three BC-
(H)dC(H)But groups linked to the cage as occurs in 6.
Evidently for electronic or steric reasons the replace-
ment of a CO molecule in the fragment Ru(CO)2(η5-7,8-
C2B9H11) by a PPh3 group inhibits the pathway by which
the trisubstituted cage would be formed. It seems
probable that displacement of the η2-9-(E)-BC(H)dC(H)-
But group in 9 by a third molecule of ButCtCH to afford
the intermediate [Ru(CO)(PPh3)(η2-ButCtCH)(η5-9,10-
{C(H)dC(H)But}2-7,8-C2B9H9)] would be a necessary
step toward introducing a third BC(H)dC(H)But group.
Conversion of this intermediate into a product akin to
6 but with an Ru(CO)(PPh3) group would then follow.
Although complexes [Ru(CO)(PPh3)(η2-RCtCH)(η5-7,8-
C2B9H11)] (R ) Ph, But) were not isolated in the
reactions which afford 8 and 9, it is reasonable to
assume that they are involved along the reaction
pathway. With a large excess of RCtCH the η2-alkyne
complex could be present in minor amounts in equilib-
rium with 5, and this equilibrium is carried forward on
formation of a BC(H)dC(H)R group, allowing the reac-
tion to proceed to the end products.
1
spectra of 13 are as expected (Tables 2 and 3). The H
and 13C{1H} NMR spectra show resonances for the cage
CH groups at δ 0.18 and 3.05 and at δ 60.2 and 39.7,
respectively. In each pair of signals the chemical shifts
are disparate, as expected because of the highly asym-
metric cage structure. Resonances for the BC(H)dCH2
group are also readily apparent in the H and 13C{1H}
1
spectra, while in the 11B{1H} spectrum one peak (δ 9.2)
remained a singlet in a fully coupled 11B spectrum and
can thus be assigned to the dCHB group.
It is likely that traces of water either in the glassware
or present in the solvents, although the latter were
vigorously dried, are responsible for cleavage of the silyl
group observed in the formation of 13. This feature has
been observed previously by others4-6 and by us.7 In our
system traces of water would convert the initially
formed alkyne η2-complex [Ru(CO)(PPh3)(Me3SiCtCH)-
(η5-7,8-C2B9H11)] into [Ru(CO)(PPh3)(HCtCH)(η5-7,8-
C2B9H11)]. Rearrangement of the latter to the vinylidene
complex [Ru(dCdCH2)(CO)(PPh3)(η5-7,8-C2B9H11)] would
It was of interest to determine whether the η2 bonding
mode of the ruthenium-coordinated C(H)dC(H)But group
in 9 could be lifted by treatment of the complex with
donor molecules. It has been previously shown that 6
reacts with PMe3 to give [Ru(CO)2(PMe3)(η5-9,10,11-{C-
(H)dC(H)But}3-7,8-C2B9H8)].2b Solutions of 9 reacted
with PMe3, CNBut, and CO to afford the compounds
[Ru(L)(CO)(PPh3)(η5-9,10-{(E)-C(H)dC(H)But}2-7,8-
C2B9H9)] (L ) PMe3 (10), CNBut (11), CO (12)), char-
acterized by the information given in Tables 1-3. The
NMR data for these structurally similar molecules are
(4) Knaup, W.; Werner, H. J . Organomet. Chem. 1991, 411, 471.
Ho¨hn, A.; Otto, H.; Dziallis, M.; Werner, H. J . Chem. Soc., Chem.
Commun. 1987, 852. Ho¨hn, A.; Werner, H. J . Organomet. Chem. 1990,
382, 255.
(5) Espuelas, J .; Esteruelas, M. A.; Lahoz, F. J .; Oro, L. A.; Ruiz, N.
J . Am. Chem. Soc. 1993, 115, 4683.
(6) Buil, M. L.; Eisenstein, O.; Esteruelas, M. A.; Garc´ıa-Yebra, C.;
Gutie´rrez-Puebla, E.; Oliva´n, M.; On˜ate, E.; Ruiz, N. Tajada, M. A.
Organometallics 1999, 18, 4949.
(7) Dossett, S. J .; Li, S.; Mullica, D. F.; Sappenfield, E. L.; Stone, F.
G. A. J . Chem. Soc., Dalton Trans. 1993, 3551.
1
in accord with their formulations. Thus, the H and 13C-

Ruthenacarborane-Terminal Alkyne Reactions
Organometallics, Vol. 19, No. 10, 2000 1989
Sch em e 1. F or m a tion of th e Deu ter a ted
Com p lexes 13a a n d 13ba
then take place, and this would be followed by insertion
into a BH vertex in the R-site in the CCBBB ring
ligating the ruthenium to give 13. A similar pathway
proceeding through the well-established8,9 process of an
initially formed η2-alkyne-metal complex transforming
into a vinylidene-metal species would also account for
the formation of 8 and 9. It has been noted6 that the
π-alkyne-vinylidene isomerization is more favored for
ButCtCH and Me3SiCtCH than it is for PhCtCH. This
may account for the reaction between 5 and PhCtCH
giving 8 having one C(H)dC(H)Ph group, whereas
ButCtCH gives 9 with two C(H)dC(H)But groups.
However, only one C(H)dCH2 group is present in 13 so
that other factors beside the π-alkyne-vinylidene rear-
rangement must be important; no doubt the steric and
electronic requirements of the PPh3 ligand play a part.
To demonstrate the importance of water in the
formation of 13, a small quantity of D2O was added to
the mixture containing 1 in THF with TlPF6 before
treatment with Me3SiCtCH. Workup of the product, as
in the synthesis of 13, led to the isolation of a 1:1
mixture of the two isomers [Ru(CO)(PPh3)(η2:η5-9-(Z)-
C(H)dC(H)D-7,8-C2B9H10)] (13a ) and [Ru(CO)(PPh3)(η2:
η5-9-(E)-C(H)dC(H)D-7,8-C2B9H10)] (13b) (Scheme 1).
Structural assignments for the isomers were made from
1
2
the 13C{1H}, H, and H NMR spectra of the mixture.
Comparison of the 13C{1H} NMR spectrum of 13a ,b with
that of the nondeuterated compound 13 showed that the
peak at δ 60.7 becomes a somewhat broad triplet with
J (2HC) ) 25 Hz, confirming that only one D atom is
2
bound to this carbon. The H NMR spectrum (Support-
ing Information) displays two signals at δ 3.69 and 2.04
in a ratio of 1:1, as a result of the two alternative
deuterium environments. The presence of the C(H)D
group in 13a and 13b clearly implicates the dCdC(H)D
vinylidene intermediate in the reaction.
When it is heated to reflux temperatures in THF,
compound 13 reacts with CNBut to give [Ru(CO)(PPh3)-
(CNBut)(η5-9-C(H)dCH2-7,8-C2B9H10)] (14), data for
which are given in Tables 1-3. However, to establish
the structure unambiguousy, an X-ray crystallographic
study was carried out. Selected structural parameters
are listed in Table 6, and the molecule is shown in
Figure 4. The ruthenium is coordinated on one side by
the CO, PPh3, and CNBut groups and on the other by
the nido-9-C(H)dCH2-7,8-C2B9H10 framework. Hence,
14 is derived from 13 by displacement of the η2-C(H)d
CH2 moiety in the latter by the CNBut molecule in a
process similar to the formation of 11 from 9. The
reaction of 13 with PMe3 follows a different pathway,
yielding the ylide complex [Ru(CO)(PPh3){σ: η5-9-C(H)-
(PMe3)CH2-7,8-C2B9H9}] (15) (Tables 1-3). The NMR
data are in agreement with the formulation. The 1H and
13C{1H} NMR spectra show resonances for the cage CH
groups at δ 0.40 and 2.39 and at δ 30.4 and 47.2,
respectively. Peaks for the BC(H)P-CH2 group occur
a
The basic mechanism is taken from ref 8.
nuclei. In the 31P{1H} NMR spectrum the PMe3 and
PPh3 groups give rise to two resonances at δ 24.2 and
50.9, respectively, as expected. The ylide complex [Ru-
(CO)2{σ:η5-10-C(H)(PMe2Ph)CH2-7,8-C2B9H10}], related
to 15, was obtained earlier as the product of the reac-
tion of PMe2Ph with [Ru(CO)2{η2:η5-10-C(H)dCH2-7,8-
C2B9H10}].2b
Con clu sion s
The results described in this paper together with
those reported earlier2b show that the two fragments
Ru(CO)(L)(η5-7,8-C2B9H11) (L ) CO, PPh3) display dif-
ferent reactivity patterns toward alkenes and alkynes.
Several stable compounds of the formulation [Ru(CO)2-
(alkene)(η5-7,8-C2B9H11)] exist, as do alkyne complexes
of the type [Ru(CO)2(RCtCR′)(η5-7,8-C2B9H11)], while
the presence of the phosphine PPh3 in place of a CO
prevents stable alkene or internal alkyne coordination.
Whereas in reactions with monosubstituted alkynes
RCtCH compounds with up to three cage B-(E)-C(H)d
C(H)R groups can be isolated from reactions involving
the Ru(CO)2(η5-7,8-C2B9H11) fragment, only species with
1
in the H spectrum at δ 1.18, 1.53, and 2.18 with the
expected 1H and 31P couplings and in the 13C{1H}
spectrum at δ 22.7 and 18.1 (Table 2), reflecting the
saturated nature of the carbon atoms. The former sig-
nal is broad, as expected due to the nearby boron 11B
(8) Silvestre, J .; Hoffmann, R. Helv. Chim. Acta 1985, 68, 1461.
(9) (a) Bruce, M. I.; Swincer, A. G. Adv. Organomet. Chem. 1983,
22, 59. (b) Bruce, M. I. Chem. Rev. 1991, 91, 197.

1990 Organometallics, Vol. 19, No. 10, 2000
Du 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 (CNBu t)(CO)(P P h 3){η5-9-C(H)dCH2-7,8-C2B9H10}]‚CH2Cl2 (14)
Ru-C(3)
Ru-C(2)
B(3)-C(4)
N(6)-C(7)
1.846(4)
2.262(3)
1.571(7)
1.453(4)
Ru-C(6)
Ru-B(4)
C(3)-O(3)
1.989(4)
2.287(4)
1.145(4)
Ru-B(5)
Ru-B(3)
C(4)-C(5)
2.251(4)
2.305(4)
1.347(13)
Ru-C(1)
Ru-P
C(6)-N(6)
2.256(3)
2.3366(9)
1.152(4)
C(3)-Ru-C(6)
C(3)-Ru-C(1)
C(6)-Ru-C(2)
C(3)-Ru-B(3)
C(6)-Ru-P
92.1(2)
159.15(14)
87.65(14)
90.9(2)
88.04(10)
138.74(11)
121.6(4)
130.0(4)
C(5)-C(4)-B(3)
N(6)-C(7)-C(9)
N(6)-C(7)-C(8)
C(3)-Ru-B(5)
C(6)-Ru-C(1)
C(3)-Ru-B(4)
C(6)-Ru-B(3)
B(5)-Ru-P
124.2(8)
B(4)-Ru-P
119.75(11)
122.7(4)
111.2(3)
175.2(3)
107.1(3)
112.0(4)
149.9(2)
132.4(2)
C(6)-Ru-B(4)
C(3)-Ru-P
151.6(2)
107.2(3)
107.8(3)
117.8(2)
106.40(14)
83.2(2)
C(4)-B(3)-B(8)
C(4)-B(3)-Ru
N(6)-C(6)-Ru
N(6)-C(7)-C(10)
C(9)-C(7)-C(8)
C(6)-Ru-B(5)
C(3)-Ru-C(2)
88.78(11)
101.22(10)
166.57(11)
115.1(3)
175.4(3)
178.0(4)
C(1)-Ru-P
B(3)-Ru-P
C(4)-B(3)-B(7)
O(3)-C(3)-Ru
C(6)-N(6)-C(7)
C(9)-C(7)-C(10)
C(2)-Ru-P
C(4)-B(3)-C(2)
C(4)-B(3)-B(4)
105.4(2)
88.99(11)
111.5(4)
diameter. The NMR measurements were recorded at the
following frequencies: 1H at 360.13 MHz, 13C at 90.56 MHz,
11B at 115.55 MHz, and 31P at 145.78 MHz. The 1H-1H
COSY45 NMR spectrum of 9 in CD2Cl2 required a 512 × 1024
point spectral matrix, with 8 transients per 1024 time-domain
points, giving an accumulation time of ca. 9 min in total. For
the transformation, sine-bell window functions were used for
both the f1 and f2 dimensions. The reagents [K(18-crown-6)]-
[RuH(L)(PPh3)(η5-7,8-C2B9H11)] (L ) CO, PPh3) and [Ru(CO)-
(PPh3)2(η5-7,8-C2B9H11)] were prepared as described previ-
ously.1
Syn th esis of [K(18-cr ow n -6)][Ru Cl(CO)(P P h 3)(η5-7,8-
C2B9H11)]. An Et2O (ca. 10 mL) suspension of [K(18-crown-
6)][RuH(CO)(PPh3)(η5-7,8-C2B9H11)] (0.05 g, 0.06 mmol) was
treated with an excess of HCl‚Et2O and the mixture stirred
overnight, affording a red-orange solid. After removal of
solvent in vacuo the residue was crystallized twice from CH2-
Cl2-Et2O to afford analytically pure deep orange or red
crystals of [K(18-crown-6)][RuCl(CO)(PPh3)(η5-7,8-C2B9H11)] (1;
0.05 g).
Syn th esis of [K(18-cr ow n -6)][Ru Cl(P P h 3)2(η5-7,8-C2B9-
11)]. A rapidly stirred Et2O (ca. 10 mL) suspension of [K(18-
H
crown-6)][RuH(PPh3)2(η5-7,8-C2B9H11)] (0.05 g, 0.05 mmol),
cooled to ca. -78 °C, was treated dropwise with 1 mol equiv
of HCl‚Et2O and the mixture stirred for 1-2 h, giving a red-
orange solid. Overly rapid addition of HCl or insufficient
cooling results in the formation of significant amounts of [Ru-
(H)2(PPh3)2(η5-7,8-C2B9H11)]. After removal of solvent in vacuo,
crystallization and recrystallization of the solid from CH2Cl2-
Et2O afforded analytically pure deep red crystals of [K(18-
crown-6)][RuCl(PPh3)2(η5-7,8-C2B9H11)] (2; 0.04 g).
Syn t h esis of [NE t4][R u I(CO)(P P h 3)(η5-7,8-C2B9H 11)].
The compounds [Ru(CO)(PPh3)2(η5-7,8-C2B9H11)] (0.50 g, 0.60
mmol) and NEt4I (0.16 g, 0.60 mmol) were placed in a Schlenk
tube, which was evacuated. After addition of THF (30 mL) the
resulting suspension was brought gradually to a brisk reflux.
Heating was continued for 1-2 days, affording a red solution.
Completion of the reaction was determined by disappearance
of the IR band at 1963 cm-1 due to [Ru(CO)(PPh3)2(η5-7,8-
C2B9H11)] and the growth of the band at 1940 cm-1 due to the
product. Solvent was removed in vacuo, the residue taken up
in CH2Cl2 (10 mL), and the mixture cooled to 0 °C overnight.
After removal of a white precipitate by filtration through
Celite, solvent was evaporated to give a deep red oil, which
was washed with benzene (3 × 10 mL), dissolved in the
minimum of CH2Cl2 (ca. 5 mL), and layered with Et2O. After
interdiffusion of the two solvents deep red crystals formed,
which were washed successively with EtOH (10 mL) and Et2O
(10 mL) and dried in vacuo to afford [NEt4][RuI(CO)(PPh3)-
(η5-7,8-C2B9H11)] (3; 0.48 g).
F igu r e 4. Structure of [Ru(CNBut)(CO)(PPh3){η5-9-C(H)d
CH2-7,8-C2B9H10}] (14), showing the crystallographic label-
ing scheme. Except for H(4a), H(5a), and H(5b), hydrogen
atoms are omitted for clarity, and thermal ellipsoids are
shown at the 40% probability level.
up to two such groups are formed when the Ru(CO)-
(PPh3)(η5-7,8-C2B9H11) fragment is the precursor. An-
other difference in the behavior of the two fragments
toward the alkynes RCtCH is that the phosphine-
containing precursor directs cage substitution to an
R-boron site in the CCBBB ring ligating the ruthenium,
whereas mixtures of R- and â-isomers are formed in
reactions involving Ru(CO)2(η5-7,8-C2B9H11). The syn-
thesis of 13 from Me3SiCtCH adds to the growing
number of known reactions where the silyl group is
cleaved following coordination of the alkyne to the
metal.
Exp er im en ta l Section
Gen er a l Con sid er a tion s. All experiments were conducted
under an atmosphere of dry nitrogen using Schlenk tube
techniques. Solvents were freshly distilled under nitrogen from
appropriate drying agents before use. Light petroleum refers
to that petroleum ether fraction of boiling point 40-60 °C.
Chromatography columns (ca. 20 cm in length and 2 cm in
diameter, unless otherwise stated) were packed with silica gel
(Acros, 60-200 mesh). TLC was performed on preparative
UNIPLATES (silica gel G, Analtech). Celite pads, used where
necessary for filtration, were ca. 3 cm in length and 2 cm in
Syn th esis of [Ru (CNBu t)(CO)(P P h 3)(η5-7,8-C2B9H11)]. A
mixture of [Ru(CO)(PPh3)2(η5-7,8-C2B9H11)] (0.05 g, 0.06 mmol)
and CNBut (0.01 mL, 0.06 mmol) in CH2Cl2 (30 mL) was
refluxed for ca. 12 h, affording a pale yellow solution. Solvent
was removed in vacuo and the residue triturated with Et2O
(10 mL) to afford a crude off-white solid. The residue was

Ruthenacarborane-Terminal Alkyne Reactions
Organometallics, Vol. 19, No. 10, 2000 1991
Ta ble 7. Da ta for X-r a y Cr ysta l Str u ctu r e An a lyses
3
8
14
cryst dimens (mm)
formula
Mr
0.40 × 0.30 × 0.30
0.71 × 0.17 × 0.13
C29H32B9OPRu
625.88
0.74 × 0.32 × 0.22
C28H37B9NOPRu‚CH2Cl2
717.84
C
29H46B9INOPRu‚0.5CH2Cl2
823.36
cryst color, shape
cryst syst
space group
a (Å)
b (Å)
c (Å)
red-orange blocks
monoclinic
P21/c
10.1874(23)
29.2144(16)
13.2192(12)
orange needles
triclinic
P1h
yellow needles
monoclinic
P21/n
10.5524(14)
21.874(3)
16.1080(11)
9.477(2)
10.7559(12)
16.343(2)
109.085(10)
94.810(13)
107.214(12)
1481.6(3)
2
1.403
6.07
636
293
R (deg)
â (deg)
104.392(11)
102.821(8)
γ (deg)
V (Å3)
3810.8(10)
4
1.435
13.6
1652
293
3625.4(7)
4
1.316
6.48
1464
293
Z
d
calcd (g cm-3
)
µ(Mo KR) (cm-1
F(000) (e)
)
T (K)
2θ range (deg)
3.5-50.0
4.0-45.0
3.2-50.0
6715
6361
5070
no. of rflns coll (excld stds)
no. of unique rflns
no. of obsd rflns
6944
4131
6554
5114
3852
3432
rfln limits: h, k, l
-12 to 0, 0 to +34, -15 to +15 -10 to 0, -11 to +11, -17 to +17 0 to +12, 0 to +25, -19 to +18
no. of params refined
452
376
438
final residuals wR2 (R1), all data 0.0891 (0.0388)a
0.0799 (0.0300)a
a ) 0.0447, b ) 0.8938
1.092
0.0890 (0.0353)a
a ) 0.0208, b ) 4.5979
1.090
weighting factorsa
a ) 0.0278, b ) 7.4759
1.068
goodness of fit on F2
final electron density diff
0.513, -0.434
0.351, -0.444
0.421, -0.663
features (max/min) (e Å-3
)
Refinement was block full-matrix least squares on all F2 data: wR2 ) [∑{w(Fo - Fc2)2}/∑w(Fo2)2]1/2, where w-1 ) [σ2(Fo2) + (aP)2
+bP] and P ) [max(Fo2,0) + 2Fc2]/3. The value in parentheses is given for comparison with refinements based on Fo with a typical threshold
of Fo > 4σ(Fo) and R1 ) ∑||Fo| - |Fc||/∑|Fo| and w-1 ) [σ2(Fo) + g(Fo2)].
a
2
dissolved in CH2Cl2 (2 mL), whereupon diffusion into an Et2O
layer at 25 °C gave a colorless powder which was washed
successively with ethanol (2 × 10 mL) and petroleum ether
(10 mL) and dried in vacuo to give [Ru(CNBut)(CO)(PPh3)(η5-
7,8-C2B9H11)] (4; 0.04 g).
Rea ction s of [K(18-cr ow n -6)][Ru Cl(CO)(P P h 3)(η5-7,8-
C2B9H11)] w ith Alk yn es. (i) Compound 1 (0.10 g, 0.12 mmol)
and TlPF6 (0.04 g, 0.12 mmol) were placed in a Schlenk tube,
which was evacuated, and THF (20 mL) was added. The
mixture was stirred for 1 h, and the resultant orange suspen-
sion was treated with PhCtCH (0.04 mL, 0.36 mmol) and
further stirred for 20 min. Separation by TLC using CH2Cl2-
petroleum ether (1:3) as eluant gave a major yellow band (Rf
) 0.62) from which [Ru(CO)(PPh3)(η2: η5-9-(E)-C(H)dC(H)Ph-
7,8-C2B9H10)] (8) was isolated (0.04 g).
(ii) Similarly 1 (0.10 g, 0.12 mmol) and TlPF6 (0.04 g, 0.12
mmol) were stirred in THF (20 mL) for 1 h and ButCtCH (0.04
mL, 0.36 mmol) was added. The suspension was further stirred
overnight. Solvent was removed in vacuo, the residue dissolved
in the minimum of CH2Cl2 (ca. 5 mL), and the mixture
chromatographed. Elution with CH2Cl2-petroleum ether (1:
4) gave an orange fraction, which on removing the solvent in
vacuo and washing the residue with petroleum ether yielded
orange microcrystals of [Ru(CO)(PPh3){η2: η5-9-(E)-C(H)dC(H)-
But-10-C(H)dC(H)But-7,8-C2B9H9}] (9; 0.05 g).
(iii) Compounds 1 (0.10 g, 0.12 mmol) and TlPF6 (0.04 g,
0.12 mmol) were placed in a Schlenk tube, which had been
evacuated, and THF (20 mL) was added. After it was stirred
for 1 h, the orange suspension was treated with Me3SiCtCH
(0.05 mL, 0.35 mmol), with stirring continued overnight. The
mixture was then chromatographed, and elution with CH2-
Cl2-petroleum ether (1:3) removed a broad yellow band.
Evaporating the solvent in vacuo from the eluate and washing
the residue with petroleum ether gave yellow microcrystals
of [Ru(CO)(PPh3)(η2: η5-9-C(H)dCH2-7,8-C2B9H10)] (13; 0.06 g).
Syn th esis of [Ru (CO)(P Me3)(P P h 3)(η5-9,10-{(E)-C(H)d
C(H)Bu t}2-7,8-C2B9H9)]. Compound 9 (0.05 g, 0.07 mmol),
dissolved in petroleum ether (40 mL), was treated with PMe3
(0.07 mL, 1 M in THF). Instantaneous formation of a yellow
precipitate was observed. After the mixture was stirred for 3
h, the solvent was decanted and the residue was washed with
petroleum ether (3 × 10 mL) to yield a yellow powder of [Ru-
(CO)(PMe3)(PPh3)(η5-9,10-{(E)-C(H)dC(H)But}2-7,8-C2B9H9)]
(10; 0.05 g).
Syn th esis of [Ru (CNBu t)(CO)(P P h 3)(η5-9,10-{(E)-C(H)d
C(H)Bu t}2-7,8-C2B9H9)]. Compound 9 (0.05 g, 0.07 mmol), in
THF (20 mL), was treated with CNBut (0.03 mL, 0.27 mmol).
The color of the solution immediately changed from orange to
yellow. After the mixture had been stirred for 1 h, the solvent
was removed in vacuo and the residue dissolved in CH2Cl2 (ca.
2 mL) and chromatographed. Elution with CH 2Cl2-petroleum
ether (1:1) removed a yellow fraction, which after evaporating
the solvent in vacuo and washing the oily residue with
petroleum ether (2 × 5 mL) yielded [Ru(CNBut)(CO)(PPh3)-
(η5-9,10-{(E)-C(H)dC(H)But}2-7,8-C2B9H9)] (11; 0.05 g) as a
yellow solid.
Syn th esis of [Ru (CO)2(P P h 3)(η5-9,10-{(E)-C(H)dC(H)-
Bu t}2-7,8-C2B9H9)]. Compound 9 (0.05 g, 0.07 mmol) was
dissolved in THF (20 mL), and CO was bubbled through the
solution for 3 h, during which time the color changed from
orange to yellow. Solvent was removed in vacuo and the
residue dissolved in CH2Cl2 (ca. 2 mL) and chromatographed.
Elution with CH2Cl2-petroleum ether (2:3) removed a yellow
fraction, which on evaporating the solvent and washing the
oily residue with petroleum ether (2 × 5 mL) afforded [Ru-
(CO)2(PPh3)(η5-9,10-{(E)-C(H)dC(H)But}2-7,8-C2B9H9)] (12; 0.04
g) as yellow microcrystals.
Syn th esis of [Ru (CNBu t)(CO)(P P h 3)(η5-9-C(H)dCH2-
7,8-C2B9H10)]. Compound 13 (0.05 g, 0.09 mmol) was dissolved
in THF (20 mL) with CNBut (0.04 mL, 0.36 mmol) and the
mixture heated to reflux overnight. After the mixture was
cooled to room temperature, solvent was removed in vacuo and
the residue dissolved in CH2Cl2 (2 mL) and chromatographed.
Elution with CH2Cl2-petroleum ether (1:1) removed a yellow

1992 Organometallics, Vol. 19, No. 10, 2000
Du et al.
fraction, which on evaporation of solvent in vacuo yielded pale
yellow microcrystals of [Ru(CNBut)(CO)(PPh3)(η5-9-C(H)dCH2-
7,8-C2B9H10)] (14; 0.05 g).
or carbon atoms with fixed isotropic thermal parameters (Uiso
) 1.2Uiso of the parent atom except for Me protons, where Uiso
) 1.5Uiso). Hydrogens H(4a) and H(5a) for 8, H(4a), H(5a),
H(10a), and H(11a) for 9, H(4a), H(5a), and H(5b) for 13, and
H(5a), H(5b), H(5a1), and H(5b1) for 14 were located in
difference Fourier maps, and their positional parameters were
refined while their isotropic thermal parameters were con-
strained to 1.2 times the Uiso value of the parent carbon atoms.
The ethyl groups of the [NEt4] cation in 3 were disordered,
with each methylene carbon atom (C(51), C(53), C(55), and
C(57); C(51A), C(53A), C(55A), and C(57A)) occupying two
distinct sites. The methyl carbon atoms (C(52), C(54), C(56),
and C(58); C(52A), C(54A), C(56A), and C(58A)) were con-
strained with the same positional and thermal parameters.
The site occupancy factors were fixed at 0.5. Compound 3 also
crystallized with a molecule of CH2Cl2, which was found to
reside near a center of inversion and was refined with a site
occupancy factor of 0.5. This molecule was disordered, as is
evident from the high thermal parameters and the residual
electron density in the difference Fourier syntheses located
in this region, but no attempt was made to resolve the disorder.
The bond lengths and angles of the CH2Cl2 group were
restrained. The methyl groups of one of the CHdCHBut
ligands in 9 are disordered over two sites such that the two
sets of methyl substituents are rotated 30° about the C(11)-
C(12) bond. The pendant CHdCH2 group in 14 was disordered
over two sites in a 60:40 ratio. The chlorine atoms of the
solvent molecule of 14 are disordered over two sites (70:30).
In 3, residual electron density was located in the vicinity of
the disordered CH2Cl2 molecule. In 8, 9, 13, and 14 insignifi-
cant residual electron density in the difference Fourier syn-
theses was found near the Ru atoms.
Syn th esis of [Ru (CO)(P P h 3)(σ:η5-9-C(H)(P Me3)CH2-7,8-
C2B9H10)]. Compound 13 (0.05 g, 0.09 mmol) was dissolved
in petroleum ether (30 mL), and PMe3 (0.11 mL,1 M in THF)
was added. The suspension was stirred for 3 h, and the solvent
was decanted to give pale yellow microcrystals of [Ru(CO)-
(PPh3)(σ: η5-9-C(H)(PMe3)CH2-7,8-C2B9H9)] (15; 0.05 g).
Cr ysta l Str u ctu r e Deter m in a tion s a n d Refin em en ts.
Experimental data for 3, 8, and 14 are shown in Table 7. Those
for 9 and 13 are provided in the Supporting Information.
Diffracted intensities were collected on an Enraf-Nonius
CAD-4 operating in the ω-2θ scan mode, using graphite-
monochromated Mo KR X-radiation. Final unit cell dimensions
were determined from the setting angles of 25 accurately
centered reflections. Crystal stability during the data collection
was monitored by measuring the intensities of three standard
reflections every 2 h. Data were collected at a varied rate of
4.13-5.17° min-1 in ω with a scan range of 1.15 + 0.34 tan θ
for 3, a constant scan speed of 5.17° min-1 in ω with a scan
range of 0.95 + 0.34 tan θ for 13, a constant scan speed of
5.17° min-1 in ω with a scan range of 1.15 + 0.34 tan θ for 8
and 14, and a varied rate of 4.13-5.17° min-1 in ω with a scan
range of 1.00 + 0.34 tan θ for 9. The data were corrected for
Lorentz, polarization, and X-ray absorption effects, the last
using either a face-indexed method based on the measure-
ments of 6 crystal faces for 8, 13, and 14 or a semiempirical
method based on azimuthal scans of ψ-data for 3 and 9.
The structures were solved by direct methods, and succes-
sive difference Fourier syntheses were used to locate all non-
hydrogen atoms using SHELXTL version 5.03.10 Refinements
were made by full-matrix least squares on all F2 data using
SHELXL-97.11 Anisotropic thermal parameters were included
for all non-hydrogen atoms. Cage carbon atoms were assigned
by comparison of the bond lengths to adjacent boron atoms in
conjunction with the magnitudes of their equivalent isotropic
thermal parameters. All hydrogen atoms, except the transoid
hydrogens of the various pendant groups, were included in
calculated positions and allowed to ride on their parent boron
Ack n ow led gm en t. We thank the Robert A. Welch
foundation for support (Grant AA-1201).
Su p p or tin g In for m a tion Ava ila ble: Tables of atomic
coordinates and U values, bond lengths and angles, and
anisotropic thermal parameters for 3, 8, 9, 13, and 14 in CIF
format and a 2H NMR spectrum of the mixture of complexes
13a and 13b. This material is available free of charge via the
Internet at http://pubs.acs.org.
(10) SHELXTL version 5.03; Bruker AXS, Madison, WI, 1995.
(11) Sheldrick, G. M. University of Go¨ttingen, Go¨ttingen, Germany,
1997.
OM000018I