Synthesis of Monocarbollide Complexes of Rhodium

Article abstract of DOI:10.1021/ic951550e

The compounds [RhX(PPh₃)₃] react with nido-7-NH₂Bu^t-7-CB₁₀H₁₂ in toluene to give the 16-electron complexes [RhX(PPh₃)(η⁵-7-NH₂Bu^t-7-CB ₁₀H₁₀)] (1a, X = Br; 1b, X = Cl). The structure of the zwitterionic molecule 1a was determined by X-ray crystallography. Crystals are monoclinic, space group P2₁/c, with a = 12.937(3) A?, b = 18.101(4) A?, c = 14.695(4) A?, β = 104.21(2)°, and Z = 4. The metal atom is coordinated on one side by Br and PPh₃ groups and on the other in the pentahapto manner by the open CBBBB face of the cage system. Reactions of the complexes with several donor molecules have been investigated. With CNBu¹, by changing the stoichiometry or work-up procedures either the 18-electron complexes [RhX(CNBu^t)(PPh₃)(η⁵-7-NH ₂Bu^t-7-CB₁₀H₁₀)] (2a, X = Br; 2b, X = Cl) or [Rh(CNBu^t)₂(PPh₃)(η⁵-7-NHBu ^t-7-CB₁₀H₁₀)] (3) are obtained, or the 16-electron complex [Rh(CNBu^t)(PPh₃)(η⁵-7-NHBu ^t-7-CB₁₀H₁₀)] (4) is formed. Formation of 3 and 4, in which the rhodium atoms are ligated by a nido-7-NHBu^t-7-CB₁₀H₁₀ cage, formally a 3 π-electron donor, is unusual and results from loss of HX from the precursors 1. To establish firmly the nature of these species, their molecular structures were determined by X-ray crystallography. Crystals of 3 are monoclinic, space group P2₁/c, with a = 10.533(2) A?, b = 19.110(4) A? c = 19.707(4) A?, β=105.413(9)°, and Z = 4, while those of 4 are triclinic, space group P1?, with a = 9.840(3) A?, b = 10.809(3) A?, c = 17.287(3) A?, α = 88.49(2)°, β= 84.57(2)°, γ = 69.809(14)°, and Z = 2. The two molecular structures are very similar: the rhodium atom is attached on one side via an η⁵-bonding mode to the open face of the 7-NHBu^t-7-CB₁₀H₁₀ cage and on the other by the PPh3 ligand and one or two CNBu^t molecules, respectively. The reactions between the compounds 1 and PEt₃, PMe₃, NC₅H₄Me-4, and tetrahydrofuran (thf) give the complexes [RhBr(PEt₃)(η⁵-7-NH₂Bu ^t-7-CB₁₀H₁₀)] (5), [RhCl(PMe₃)₂(η⁵-7-NH₂-Bu ^t-7-CB₁₀H₁₀)] (6), and [RhBr(L)(η⁵-7-NH₂Bu^t-7-CB ₁₀H₁₀)] (7a, L = NC₅H₄Me-4; 7b, L = thf), respectively. Prolonged refluxing of mixtures of [CoCl(PPh₃)₃] and nido-7-NH₂Bu^t-7-CB₁₀H₁₂ in toluene gives the arene-(carborane)-cobalt complex [Co(η⁶-C₆H₅Me)(η ⁵-7-NHBu^t-7-CB₁₀H₁₀)] (8), the structure of which was determined by X-ray diffraction. Crystals are monoclinic, space group P2₁/c, with a = 16.332(5) A?,b= 10.397(2) A?, c = 22.186(6) A?, β=102.94(2)°, and Z = 8. NMR data for the new compounds are reported and discussed in relation to their structures.

Full text of DOI:10.1021/ic951550e

Inorg. Chem. 1996, 35, 2967-2976
2967
Synthesis of Monocarbollide Complexes of Rhodium†
John C. Jeffery,‡ Vyacheslav N. Lebedev,§,| and F. Gordon A. Stone*,§
Department of Chemistry, Baylor University, Waco, Texas 76798-7348, and
School of Chemistry, The University, Bristol BS8 1TS, U.K.
ReceiVed December 6, 1995X
The compounds [RhX(PPh3)3] react with nido-7-NH2But-7-CB10H12 in toluene to give the 16-electron complexes
[RhX(PPh3)(η5-7-NH2But-7-CB10H10)] (1a, X ) Br; 1b, X ) Cl). The structure of the zwitterionic molecule 1a
was determined by X-ray crystallography. Crystals are monoclinic, space group P21/c, with a ) 12.937(3) Å, b
) 18.101(4) Å, c ) 14.695(4) Å, â )104.21(2)°, and Z ) 4. The metal atom is coordinated on one side by Br
and PPh3 groups and on the other in the pentahapto manner by the open CBBBB face of the cage system. Reactions
of the complexes with several donor molecules have been investigated. With CNBut, by changing the stoichiometry
or work-up procedures either the 18-electron complexes [RhX(CNBut)(PPh3)(η5-7-NH2But-7-CB10H10)] (2a, X
) Br; 2b, X ) Cl) or [Rh(CNBut)2(PPh3)(η5-7-NHBut-7-CB10H10)] (3) are obtained, or the 16-electron complex
[Rh(CNBut)(PPh3)(η5-7-NHBut-7-CB10H10)] (4) is formed. Formation of 3 and 4, in which the rhodium atoms
are ligated by a nido-7-NHBut-7-CB10H10 cage, formally a 3 π-electron donor, is unusual and results from loss
of HX from the precursors 1. To establish firmly the nature of these species, their molecular structures were
determined by X-ray crystallography. Crystals of 3 are monoclinic, space group P21/c, with a ) 10.533(2) Å, b
) 19.110(4) Å, c ) 19.707(4) Å, â )105.413(9)°, and Z ) 4, while those of 4 are triclinic, space group P1h, with
a ) 9.840(3) Å, b ) 10.809(3) Å, c ) 17.287(3) Å, R ) 88.49(2)°, â ) 84.57(2)°, γ ) 69.809(14)°, and Z )
2. The two molecular structures are very similar: the rhodium atom is attached on one side via an η5-bonding
mode to the open face of the 7-NHBut-7-CB10H10 cage and on the other by the PPh3 ligand and one or two
CNBut molecules, respectively. The reactions between the compounds 1 and PEt3, PMe3, NC5H4Me-4, and
tetrahydrofuran (thf) give the complexes [RhBr(PEt3)(η5-7-NH2But-7-CB10H10)] (5), [RhCl(PMe3)2(η5-7-NH2-
But-7-CB10H10)] (6), and [RhBr(L)(η5-7-NH2But-7-CB10H10)] (7a, L ) NC5H4Me-4; 7b, L ) thf), respectively.
Prolonged refluxing of mixtures of [CoCl(PPh3)3] and nido-7-NH2But-7-CB10H12 in toluene gives the arene-
(carborane)-cobalt complex [Co(η6-C6H5Me)(η5-7-NHBut-7-CB10H10)] (8), the structure of which was determined
by X-ray diffraction. Crystals are monoclinic, space group P21/c, with a ) 16.332(5) Å, b ) 10.397(2) Å, c )
22.186(6) Å, â )102.94(2)°, and Z ) 8. NMR data for the new compounds are reported and discussed in relation
to their structures.
Introduction
few icosahedral monocarbon metallacarboranes are known, in
contrast with the numerous dicarbon 12-vertex MC2B9 polyhedra
We have recently shown that the nido-carboranes 7,8-C2B9H13
and 7-NR3-7-CB10H12 (NR3 ) NMe3, NH2But, NMe2But) react
with [Ru3(CO)12] to afford, respectively, the mononuclear
ruthenium complex [Ru(CO)3(η5-7,8-C2B9H11)] and the triru-
thenium complexes [Ru3(CO)8(η5-7-NR3-7-CB10H10)].1 Forma-
tion of closo-metallacarboranes from reactions between 11-ver-
tex nido-carboranes and low-valent metal complexes would
appear to be a promising preparative route to species having
either MC2B9 or MCB10 12-vertex cage frameworks. In order
to extend the scope of this methodology we have investigated
the reaction between the nido-carborane 7-NH2But-7-CB10H12
and the compounds [RhX(PPh3)3] (X ) Cl or Br) as a possible
direct route to species with closo-RhCB10 structures, and report
herein the results of this study. At the present time relatively
which have been characterized.2 A few mono- and binuclear
rhodium monocarbon carborane complexes, however, are well
established in the literature,3,4 and some of these species are
discussed further below since they are relevant to the present
work.
Results and Discussion
In toluene at reflux temperature the compounds [RhX(PPh3)3]
(X ) Cl or Br) and nido-7-NH2But-7-CB10H12 afford the
mononuclear closo-rhodacarboranes [RhX(PPh3)(η5-7-NH2But-
7-CB10H10)] (1a, X ) Br; 1b, X ) Cl), isolated by column
chromatography and characterized by the data summarized in
Tables 1-3. These species are zwitterionic 16-electron RhIII
complexes in which the metal is ligated by an η5-7-NH2But-7-
CB10H10 group. They are closely related to the previously
reported compounds [RhBr(PPh3)(η5-7-NH2(CH2CHdCHMe)-
7-CB10H10)] and [RhBr(PPh3)(η5-7-NH(CH2CHdCHMe)2-7-
CB10H10)], which were obtained by N-quaternization of the
† The compounds described in this paper have a rhodium atom
incorporated into a closo-1-carba-2-rhodadodecaborane structure. However,
to avoid a complicated nomenclature for the complexes reported, and to
relate them to the many known rhodium species with η5-coordinated
cyclopentadienyl ligands, we treat the cages as nido-11-vertex ligands with
numbering as for an icosahedron from which the twelfth vertex has been
removed.
‡ University of Bristol.
(2) Grimes, R. N. In ComprehensiVe Organometallic Chemistry II; Abel,
E. W., Stone, F. G. A., Wilkinson, G., Eds.-in-chief; Pergamon
Press: Oxford, UK, 1995; Vol. 1 (Housecroft, C. E., Ed.), Chapter 9.
(3) (a) Walker. J. A.; O’Con, C. A.; Zheng, L.; Knobler, C. B.; Hawthorne,
M. F. J. Chem. Soc., Chem. Commun. 1983, 803. (b) Chizhevsky, I.
T.; Pisareva, I. V.; Petrovskii, P. V.; Bregadze, V. I.; Yanovsky, A.
I.; Struchkov, Yu. T.; Knobler, C. B.; Hawthorne, M. F. Inorg. Chem.
1993, 32, 3393.
§ Baylor University.
| Permanent address: A. N. Nesmeyanov Institute of Organoelement
Compounds, Russian Academy of Sciences, Vavilov St. 28, Moscow
117813, Russia.
X Abstract published in AdVance ACS Abstracts, April 15, 1996.
(1) (a) Anderson, S.; Mullica, D. F.; Sappenfield, E. L.; Stone, F. G. A.
Organometallics 1995, 14, 3516. (b) Lebedev, V. N.; Mullica, D. F.;
Sappenfield, E. L.; Stone, F. G. A. Organometallics 1996, 15, 1669.
(4) Zakharkin, L. I.; Zhigareva, G. G. Zh. Obshch. Khim. 1982, 52, 2802.
S0020-1669(95)01550-3 CCC: $12.00 © 1996 American Chemical Society

2968 Inorganic Chemistry, Vol. 35, No. 10, 1996
Jeffery et al.
Chart 1
Table 1. Analytical and Physical Data
anal.b/%
H
compda
color
red
red
orange
orange
yellow
red
red
red-orange
red
red
red
yield/%
C
N
1a
1b
2a
2b
3
4
5
[RhBr(PPh3)(η5-7-NH2But-7-CB10H10)]
56
62
86
85
61d
80e
90
82
90
82
15
42.2 (42.6)
42.5 (41.8)
42.7 (42.6)
45.2 (45.1)
53.9 (53.4)
51.8 (51.6)
31.1 (31.1)
26.4 (25.8)
48.5 (49.9)
44.3 (45.0)
40.3 (40.6)
5.5 (5.6)
5.6 (5.5)
5.7 (5.8)
6.4 (6.1)
7.9 (7.4)
6.8 (6.9)
8.3 (8.5)
8.1 (7.4)
5.8 (5.9)
6.1 (6.1)
8.1 (8.2)
2.1 (2.2)
2.2 (2.0)c
3.9 (3.4)c
3.6 (3.6)c
5.6 (5.7)
4.3 (4.3)
3.1 (3.3)
2.8 (2.5)
3.8 (3.6)f
1.8 (1.9)
3.9 (3.9)
[RhCl(PPh3)(η5-7-NH2But-7-CB10H10)]
[RhBr(CNBut)(PPh3)(η5-7-NH2But-7-CB10H10)
[RhCl(CNBut)(PPh3)(η5-7-NH2But-7-CB10H10)]
[Rh(CNBut)2(PPh3)(η5-7-NHBut-7-CB10H10)]
[Rh(CNBut)(PPh3)(η5-7-NHBut-7-CB10H10)]
[RhBr(PEt3)(η5-7-NH2But-7-CB10H10)]
6
[RhCl(PMe3)2(η5-7-NH2But-7-CB10H10)]
[RhBr(NC5H5Me-4)(PPh3)(η5-7-NH2But-7-CB10H10)]
[RhBr(thf)(PPh3)(η5-7-NH2But-7-CB10H10)]
[Co(η6-C6H5Me)(η5-7-NHBut-7-CB10H10)]
7a
7b
8
a All compounds show broad medium-intensity bands in their infra-red spectra, measured in CH2Cl2, at ca. 2550 cm-1 due to B-H absorptions.
There are also medium-intensity νmax(NC) bands observed for compounds 2a (2190 cm-1), 2b (2190 cm-1), 3 (2192, 2174 cm-1), and 4 (2180
cm-1). b Calculated values are given in parentheses. c Crystallizes with 1 molecule of CH2Cl2. d Also synthesized from compound 1b and from
compound 4 (see Experimental Section). e Also prepared from compound 1b (see Experimental Section). f Crystallizes with 0.5 molecule of C6H6.
dimeric anion present in [N(PPh3)2][Rh2(µ-H)(PPh3)2(η5-7-NH2-
7-CB10H10)2] with crotyl bromide.3b In order to establish firmly
the molecular structures of the compounds 1, a single-crystal
X-ray diffraction study was carried out on 1a. Selected
interatomic distances and angles are listed in Table 4, and the
molecule is shown in Figure 1.
On one side the rhodium atom is coordinated by PPh3 [Rh-
P 2.334(2) Å] and by Br [Rh-Br 2.5165(9) Å] groups. On the
other it is bonded to the nido-7-NH2But-7-CB10H10 cage in the
pentahapto manner [Rh-C(1) 2.240(5), Rh-B(2) 2.129(6), Rh-
B(3) 2.182(6), Rh-B(4) 2.179(6), Rh-B(5) 2.131(6) Å]. In
these respects the structure is very similar to that determined
for [RhBr(PPh3)(η5-7-NH(CH2CHdCHMe)2-7-CB10H10)]. In
the latter the Rh-P distance is 2.354(1) Å, the Rh-C(1)
connectivity is 2.243(5) Å, and the Rh-B separations are 2.127-
(5)-2.174(5) Å.3b However, this study revealed a somewhat
shorter than expected Rh-Br distance [2.488(1) Å], attributable
to some Br sites in the crystal being occupied by Cl atoms due
to halide exchange. In contrast, in 1a the Rh-Br bond length
is similar to that found (average 2.530 Å) in several other
mononuclear rhodium complexes containing this group,5 and
may be compared with the similar distances in the salt [PHPh3]-
[RhBr2(PPh3)(η5-7,8-C2B9H11)] [2.520(2) and 2.598(1) Å].6
An intramolecular N-H‚‚‚Br hydrogen bond is present in
[RhBr(PPh3)(η5-7-NH(CH2CHdCHMe)2-7-CB10H10)], a struc-
tural feature revealed by N‚‚‚Br and Br‚‚‚H distances of 3.074-
(6) and 1.92(7) Å, respectively.3b In our study of 1a the NH2
protons were not located, but their inclusion in sensible
calculated positions gives the shortest distance between the NH2
hydrogens and the Br atom as 2.31 Å, from which we infer the
absence of any N-H‚‚‚Br bonding.
The NMR data for the species 1 are given in Tables 2 and 3.
The 1H NMR spectra show broad signals for the NH2 groups at
δ 9.80 (1a) and δ 8.30 (1b), corresponding in intensity to two
(5) Orpen, A. G.; Brammer, L.; Allen, F. H.; Kennard, O.; Watson, D.
G.; Taylor, R. J. Chem. Soc., Dalton Trans. 1989, S1.
(6) Zheng, L.; Baker, R. T.; Knobler, C. B.; Walker, J. A.; Hawthorne,
M. F. Inorg. Chem. 1983, 22, 3350.

Synthesis of Monocarbollide Complexes of Rhodium
Inorganic Chemistry, Vol. 35, No. 10, 1996 2969
13C/δc,d
Table 2. Hydrogen-1 and Carbon-13 NMR Dataa
compd
1H/δb
1a
1b
2a
1.65 (s, 9 H, CMe3), 7.46-7.57 (m, 15 H, Ph), 9.80 (br s, 2 H, NH2) e135.6-129.1 (Ph), 76.5 (CB10H10), 66.0 (NCMe3), 27.0 (CMe3)
1.61 (s, 9 H, CMe3), 7.43-7.54 (m, 15 H, Ph), 8.30 (br s, 2 H, NH2) 134.9-128.6 (Ph), 75.8 (CB10H10), 66.3 (NCMe3), 27.2 (CMe3)
1.28, 1.51 (s × 2, 18 H, CMe3), 6.75 [d, 1 H, NH2, J(HH) ) 13],
7.36-7.77 (m, 15 H, Ph), 7.95 [d, 1 H, NH2, J(HH) ) 13]
1.27, 1.50 (s × 2, 18 H, CMe3), 6.85 [d, 1 H, NH2, J(HH) ) 13],
7.40-7.80 (m, 15 H, Ph), 8.32 [d, 1 H, NH2, J(HH) ) 13]
1.26 (s, 18 H, CNCMe3), 1.17 (s, 9 H, NHCMe3),
3.50 (br s, 1 H, NH), 7.43-7.50 (m, 15 H, Ph)
135.5-127.8 (Ph), 82.3 [d of d, CB10H10, J(PC) ) 39, J(RhC) ) 10],
66.6 (NCMe3), 58.3 (CMe3), 29.7, 27.6 (CMe3)
135.2-127.9 (Ph), 83.7 [d of d, CB10H10, J(PC) ) 40, J(RhC) ) 10],
65.9 (NCMe3), 58.1 (CMe3), 29.7, 27.6 (CMe3)
134.7-128.1 (Ph), 106.5 (br, CB10H10), 58.1, 54.4 (CMe3),
30.8, 29.6 (CMe3)
134.7-128.6 (Ph), 118.7 (br, CB10H10), 58.1, 57.7 (CMe3),
31.3, 29.7 (CMe3)
73.1 (CB10H10), 54.0 (CMe3), 27.1 (CMe3), 17.5 [d, PCH2,
J(PC) ) 30], 8.2 (CH2Me)
2b
3
4
1.14, 1.20 (s × 2, 18 H, CMe3), 3.15 (br s, 1 H, NH),
7.43-7.51 (m, 15 H, Ph)
1.13 (m, 9 H, CH2Me), 1.63 (s, 9 H, CMe3), 2.15 (m, 6 H, PCH2),
8.20 (br s, 2 H, NH2)
5
6
7a
1.38 (s, 9 H, CMe3), 1.69 (m, 18 H, PMe), 7.25 (br s, 2 H, NH2)
1.57 (s, 9 H, CMe3), 2.35 (s, 3 H, NC5H4Me-4), 7.06-7.51
(m, 19 H, Ph and NC5H4Me-4), 8.55 (br s, 2 H, NH2)
1.63 (s, 9 H, CMe3), 1.84 (m, 4 H, CH2), 3.69 (m, 4 H, CH2O),
7.39-7.55 (m, 15 H, Ph), 8.51 (br s, 2 H, NH2)
1.52 (s, 9 H, CMe3), 2.58 (br s, 1 H, NH), 2.67 (s, 3 H, Me),
6.28-6.92 (m, 5 H, Ph)
65.5 (CMe3), 27.1 (CMe3), 19.2 [d, PMe, J(PC) ) 33]
150.2-125.4 (Ph and NC5H4Me-4), 78.2 (CB10H10), 65.3 (CMe3),
27.3 (CMe3), 20.2 (NC5H4Me-4)
7bf
8
121.6 (vbr, CB10H10), 119.7 (C1, C6H5Me), 109.5, 108.8
(C2, C3, C6H5Me), 107.7 (C4, C6H5Me), 56.5 (CMe3),
30.4 (CMe3), 20.7 (C6H5Me)
a Chemical shifts (δ) in ppm, coupling constants (J) in Hz, measurements at room temperature in CD2Cl2 unless otherwise stated. b Resonances
for terminal BH protons occur as broad unresolved signals in the range δ ca. -1 to 2.5. c Hydrogen-1 decoupled; chemical shifts are positive to
high frequency of SiMe4. d Signals for CNBut nuclei not observed in spectra of compounds 2, 3, and 4. e Measured in (CD3)2CO. f 13C{1H} not
measured due to dissociation of thf ligand.
Table 3. Boron-11 and Phosphorus-31 NMR Dataa
compd
11B/δb
31P/δc
1a
1b
2a
9.9 (3 B), 5.4 (2 B), -6.9 (1 B), -14.8 (4 B)
34.1 [d, J(RhP) ) 160]
33.8 [d, J(RhP) ) 160]
36.4 [d, J(RhP) ) 123]
9.1 (3 B), 5.9 (2 B), -6.5 (1 B), -15.1 (4 B)
10.9 (1 B), 4.9 (1 B), 0.2 (3 B), -7.7 (1 B), -10.9 (2 B),
-14.4 (1 B), -18.6 (1 B)
10.2 (1 B), 5.2 (1 B), 1.1 (1 B), -1.1 (2 B), -7.7 (1 B),
-11.0 (2 B), -14.8 (1 B), -19.2 (1 B)
13.4 (1 B), 1.6 (4 B), -9.2 (3 B), -13.6 (2 B)
17.5 (1 B), 6.1 (2 B), -0.6 (2 B), -6.9 (1 B), -13.4 (4 B)
7.9 (3 B), 3.8 (2 B), -7.4 (1 B), -15.5 (4 B)
7.3 (1 B), 0.3 (2 B), -5.2 (2 B), -10.7 (3 B), -17.4 (2 B)
9.6 (1 B), 4.9 (4 B), -7.7 (1 B), -13.7 (3 B), -15.1 (1 B)
14.8 (1 B), 11.3 (2 B), 4.2 (2 B), -5.0 (1 B), -6.5 (2 B), -9.7 (2 B)
2b
36.8 [d, J(RhP) ) 125]
3
4
5
6
7a
8
39.2 [d, J(RhP) ) 108]
33.7 [d, J(RhP) ) 133]
38.1 [d, J(RhP) ) 150]
-6.3 [d, J(RhP) ) 124]
34.0 [d, J(RhP) ) 137]
a Chemical shifts (δ) in ppm, coupling constants (J) in Hz, measurements in CD2Cl2, and at room temperature. b Hydrogen-1 decoupled; chemical
shifts are positive to high frequency of BF3‚Et2O (external). c Hydrogen-1 decoupled; chemical shifts are positive to high frequency of 85% H3PO4
(external).
Table 4. Selected Internuclear Distances (Å) and Angles (deg) for [RhBr(PPh3)(η5-7-NH2But-7-CB10H10)]‚CH2Cl2 (1a) with Estimated
Standard Deviations in Parentheses
Rh-B(2)
2.129(6)
2.240(5)
1.687(8)
1.771(9)
1.778(9)
1.869(9)
1.786(10)
1.761(10)
1.767(10)
1.570(11)
Rh-B(5)
2.131(6)
2.334(2)
1.695(8)
1.805(9)
1.800(9)
1.760(9)
1.790(10)
1.788(10)
1.545(8)
Rh-B(4)
2.179(6)
2.5165(9)
1.727(8)
1.845(9)
1.788(9)
1.801(10)
1.773(10)
1.770(10)
1.521(10)
Rh-B(3)
2.182(6)
1.488(7)
1.740(8)
1.770(9)
1.789(10)
1.776(10)
1.794(10)
1.771(10)
1.537(10)
Rh-C(1)
Rh-P
Rh-Br
C(1)-N(1)
C(1)-B(5)
B(3)-B(6)
B(4)-B(8)
B(6)-B(10)
B(7)-B(8)
B(9)-B(10)
C(2)-C(5)
C(1)-B(10)
B(2)-B(6)
B(3)-B(7)
B(4)-B(5)
B(6)-B(7)
B(8)-B(9)
B(10)-B(11)
C(2)-C(4)
C(1)-B(9)
B(2)-B(10)
B(3)-B(4)
B(5)-B(8)
B(6)-B(11)
B(8)-B(11)
N(1)-C(2)
C(1)-B(2)
B(2)-B(3)
B(4)-B(7)
B(5)-B(9)
B(7)-B(11)
B(9)-B(11)
C(2)-C(3)
B(2)-Rh-B(5)
B(2)-Rh-B(3)
B(2)-Rh-C(1)
B(3)-Rh-C(1)
B(4)-Rh-P
B(2)-Rh-Br
B(3)-Rh-Br
C(1)-N(1)-C(2)
83.0(3)
B(2)-Rh-B(4)
B(5)-Rh-B(3)
B(5)-Rh-C(1)
B(2)-Rh-P
85.3(3)
85.2(3)
46.8(2)
129.2(2)
91.7(2)
106.4(2)
B(5)-Rh-B(4)
51.4(3)
48.8(2)
83.3(2)
132.7(2)
174.2(2)
149.2(2)
90.50(4)
50.7(2)
46.5(2)
82.5(2)
92.7(2)
115.7(2)
161.7(2)
128.8(5)
B(4)-Rh-B(3)
B(4)-Rh-C(1)
B(5)-Rh-P
C(1)-Rh-P
B(4)-Rh-Br
P-Rh-Br
B(3)-Rh-P
B(5)-Rh-Br
C(1)-Rh-Br
95.10(14)
protons. In the 13C{1H} NMR spectrum resonances at δ 76.5
(1a) and δ 75.8 (1b) are tentatively assigned to the carbon nuclei
of the CB10H10 cages present in these molecules. At the present
time there is a paucity of information on 13C chemical shifts
for carbon atoms in monocarboranes,1b the chemical shifts of
which are likely to vary with the metal in the MCB10 framework
and the character of any exo-polyhedral groups. The 31P{1H}
NMR spectra for 1 have diagnostic doublet signals for the PPh3
ligands at δ 34.1 (1a) and δ 33.8 (1b), both with J(RhP) ) 160
Hz.
The compounds 1 are 16-electron coordinatively unsaturated
rhodium complexes, and as such relate in an isolobal manner

2970 Inorganic Chemistry, Vol. 35, No. 10, 1996
Jeffery et al.
NHBut-7-CB10H10)] (3) which was isolated by crystallization.
In this product the nido-cage system 7-NHBut-7-CB10H10 is
present. The latter formally donates three electrons to the
rhodium atom rather than the four electrons donated to the metal
by the charge compensated 7-NH2But-7-CB10H10 ligand in the
species 1. Evidently the reactions proceed with overall loss of
HX via deprotonation of the CNH2But group in the precursors
1
1. Careful integration of the peaks in the H NMR spectrum
of 3 (Table 2) revealed that the resonance at δ 3.50 was due to
an NH rather than an NH2 group. The other NMR data for 3
(Tables 2 and 3) were in accord with the formulation. However,
to place the molecular structure of 3 on a firm basis, a single-
crystal X-ray diffraction study was undertaken at 173 K.
Selected bond distances and angles are given in Table 5, and
the molecule is shown in Figure 2.
The nido-cage fragment adopts the customary η5-bonding
mode for attachment to the rhodium, but the significant result
of the study was confirmation that N(1) carries a single H(1)
atom, its position being both located and refined. The C(1)-
N(1) distance [1.438(3) Å] and the C(1)-N(1)-C(2) angle
[128.4(2)°] in 3 are essentially the same as those in 1a [C(1)-
N(1) 1.488(7) Å, C(1)-N(1)-C(2) 128.8(5)°]. It is noteworthy
that in the nido-carborane 7-NH2But-7-CB10H12 the cage C-N
distance is 1.508(2) Å.11 The Rh-P distance [2.3568(7) Å] is
also similar to that in 1a. The two CNBut groups are linearly
bound to the rhodium (N-C-Rh average 176°). The various
groups ligating the metal contribute 9 electrons, thus giving the
metal atom an 18-electron configuration.
In further experiments with CNBut the compounds 1 were
treated with 2 mol equiv of the isocyanide at room temperature
but the product was isolated by column chromatography rather
than by crystallization. This procedure yielded the 16-electron
rhodium complex [Rh(CNBut)(PPh3)(η5-7-NHBut-7-CB10H10)]
(4), characterized by microanalysis (Table 1) and by the NMR
data summarized in Tables 2 and 3. Not surprisingly, once
isolated, compound 4 afforded 3 on treatment with CNBut in
CH2Cl2.
Since the formation of 4 again involved an unexpected ligand
transformation from the charge-compensated moiety 7-NH2But-
7-CB10H10 to the neutral 7-NHBut-7-CB10H10, an X-ray dif-
fraction study was made on this product. Selected bond
distances and angles are given in Table 6, and the structure is
shown in Figure 3. Atom H(1) atom attached to N(1) was
located and its position refined. The C(1)-N(1) distance [1.413-
(4) Å] and C(1)-N(1)-C(2) angle [129.9(3)°] are very similar
to these same parameters for 3. The CNBut ligand is essentially
linearly bound to the metal [Rh-C(6)-N(7) 176.4(3)°], as found
for isocyanide groups in 3, and the Rh-P bond length [2.354-
(1) Å] also shows little variation from that in 3 [2.3568(7) Å].
With the possible exception of the Rh-C(1) distances [3, 2.337-
(2); 4, 2.103(3) Å] the connectivities between the rhodium and
Figure 1. Molecular structure of [RhBr(PPh3)(η5-7-NH2But-7-
CB10H10)] (1a), showing the crystallographic labeling scheme. Thermal
ellipsoids are at the 40% probability level, and hydrogen atoms are
omitted for clarity.
with the previously reported dicarbon-rhodacarborane species
[RhCl(PPh3)(η5-7,9-C2B9H11)].7 In the complexes 1, as in
[RhCl(PPh3)(η5-7,9-C2B9H11)], the electron deficiency is evi-
dently metal centered since the cages are not distorted from a
triangulated closo-icosahedral framework. The electronic and
coordinate unsaturation of the species 1 prompted a study of
their reactions with several simple electron pair donor groups.
Studies commenced using the rodlike CNBut ligand in the
expectation that this would minimize any steric effects.
Treatment of the compounds 1 in CH2Cl2 at -20 °C with 1
mol equiv of CNBut gave the complexes [RhX(CNBut)(PPh3)(η5-
7-NH2But-7-CB10H10)] (2a, X ) Br; 2b, X ) Cl). Data
characterizing these products are summarized in Tables 1-3.
The 1H and 13C{1H} NMR spectra (Table 2) of these 18-electron
complexes were informative. The chirality of the rhodium
atoms in the complexes 2 results in the 1H NMR spectra
displaying two resonances for the diastereotopic protons of the
NH2 groups, and these occur as doublets [J(HH) ) 13 Hz] at δ
6.75 and 7.95 for 2a and at δ 6.85 and 8.32 for 2b. The 13C-
{1H} NMR spectra revealed resonances at δ 82.3 (2a) and δ
83.7 (2b) which we assign to the cage-carbon nuclei. These
appear as a doublet-of-doublets due to 31P-13C and 103Rh-13C
coupling of ca. 40 and 10 Hz, respectively. No peaks were
seen in either spectrum which could be attributed to the ligating
carbon atoms of the CNBut ligand. These nuclei would be
expected to resonate in the range δ ca. 130-180.8-10 In the
13C{1H} NMR spectrum of the ruthenium cluster [Ru3(CO)7-
(CNBut)(η5-7-NMe3-7-CB10H10)] the CNBut resonance is at δ
189.4.1b Failure to observe peaks due to the CNBut nuclei in
the 13C{1H} NMR spectra of 2 and other molecules containing
this ligand, discussed below, is not surprising. Such signals
are often weak and difficult to discern,10 and for 2 these peaks
would be split by 103Rh and 31P coupling. Other resonances in
the respective spectra were as expected.
the pentagonal CBBBB ring are also closely similar in the two
compounds. Thus overall the structural parameters in common
are not influenced by 3 being an 18-electron and 4 being a 16-
electron species.
Some reactions between the compounds 1 and other donor
ligands were next investigated. Treatment of 1a in CH2Cl2 with
1 mol equiv of PEt3 gave the 16-electron complex [Rh-
Br(PEt3)(η5-7-NH2But-7-CB10H10)] (5), there being no evidence
of a stable 18-electron species [RhBr(PEt3)(PPh3)(η5-7-NH2-
But-7-CB10H10)]. Existence of the latter is perhaps inhibited
by steric effects, cone angles for PEt3 and PPh3 being 132° and
145°, respectively.12 The reaction between 1b and an excess
In contrast with these results, the reaction between either of
the complexes 1 with 2 mol equiv of CNBut in CH2Cl2 gave
the bis(isocyanide)rhodium complex [Rh(CNBut)2(PPh3)(η5-7-
(7) Baker, R. T.; Delaney, M. S.; King, R. E.; Knobler, C. B.; Long, J.
A.; Marder, T. B.; Paxson, T. E.; Teller, R. G.; Hawthorne, M. F. J.
Am. Chem. Soc. 1984, 106, 2965.
(8) Muetterties, E. L. Inorg. Chem. 1974, 13, 795.
(9) Johnston, G. G.; Baird, M. C. Organometallics 1989, 8, 1894.
(10) Jones, W. D.; Duttweiller, R. P.; Feher, F. J. Inorg. Chem. 1990, 29,
1505. Jones, W. D.; Hessell, E. T. Organometallics 1990, 9, 718.
(11) Jeffery, J. C.; Lebedev, V. N.; Stone, F. G. A. Unpublished results.

Synthesis of Monocarbollide Complexes of Rhodium
Inorganic Chemistry, Vol. 35, No. 10, 1996 2971
Table 5. Selected Internuclear Distances (Å) and Angles (deg) for [Rh(CNBut)2(PPh3)(η5-7-NHBut-7-CB10H10)] (3) with Estimated Standard
Deviations in Parentheses
Rh(1)-C(21)
Rh(1)-B(4)
B(2)-C(1)
2.010(2)
2.220(2)
1.727(3)
1.777(3)
1.775(3)
1.792(4)
1.767(4)
1.777(4)
1.772(4)
1.152(3)
Rh(1)-C(11)
Rh(1)-B(2)
B(2)-B(8)
B(3)-B(8)
B(4)-B(5)
B(6)-C(1)
B(7)-C(1)
B(8)-B(9)
C(1)-N(1)
N(11)-C(12)
2.022(2)
2.250(3)
1.780(3)
1.779(4)
1.836(3)
1.729(3)
1.723(3)
1.783(4)
1.438(3)
1.470(3)
Rh(1)-B(3)
Rh(1)-C(1)
B(2)-B(7)
B(3)-B(4)
B(5)-C(1)
B(6)-B(10)
B(7)-B(8)
B(9)-B(11)
N(1)-C(2)
C(21)-N(21)
2.211(2)
2.337(2)
1.792(4)
1.851(3)
1.773(3)
1.755(4)
1.758(4)
1.766(4)
1.485(3)
1.154(3)
Rh(1)-B(5)
Rh(1)-P
2.212(2)
2.3568(7)
1.851(4)
1.773(4)
1.781(3)
1.763(4)
1.778(4)
1.794(4)
0.74 (0.03)
1.461(3)
B(2)-B(3)
B(4)-B(10)
B(5)-B(10)
B(6)-B(7)
B(7)-B(11)
B(9)-B(10)
N(1)-H(1)
N(21)-C(22)
B(3)-B(9)
B(4)-B(9)
B(5)-B(6)
B(6)-B(11)
B(8)-B(11)
B(10)-B(11)
C(11)-N(11)
C(21)-Rh(1)-C(11)
C(21)-Rh(1)-B(5)
C(21)-Rh(1)-B(4)
B(5)-Rh(1)-B(4)
B(3)-Rh(1)-B(2)
C(21)-Rh(1)-C(1)
B(5)-Rh(1)-C(1)
C(21)-Rh(1)-P
B(5)-Rh(1)-P
90.53(9)
C(21)-Rh(1)-B(3)
C(11)-Rh(1)-B(5)
C(11)-Rh(1)-B(4)
C(21)-Rh(1)-B(2)
B(5)-Rh(1)-B(2)
C(11)-Rh(1)-C(1)
B(4)-Rh(1)-C(1)
C(11)-Rh(1)-P
99.78(9)
C(11)-Rh(1)-B(3)
168.81(9)s
82.88(9)
49.37(9)
128.96(9)
83.09(9)
79.78(8)
44.20(8)
95.43(7)
141.16(7)
128.2(2)
61.41(14)
111.1(2)
128.4(2)
176.0(2)
173.7(2)
155.06(9)
146.40(9)
48.94(9)
49.01(9)
109.91(8)
45.80(8)
89.01(6)
115.56(7)
160.96(5)
62.57(14)
111.5(2)
109.2(2)
112. (2)
85.93(9)
121.53(9)
83.64(9)
79.54(9)
92.68(8)
80.61(9)
89.04(7)
82.35(7)
116.0(2)
110.0(2)
117.2(2)
61.51(14)
112 (2)
B(3)-Rh(1)-B(5)
B(3)-Rh(1)-B(4)
C(11)-Rh(1)-B(2)
B(4)-Rh(1)-B(2)
B(3)-Rh(1)-C(1)
B(2)-Rh(1)-C(1)
B(3)-Rh(1)-P
B(4)-Rh(1)-P
B(2)-Rh(1)-P
C(1)-Rh(1)-P
N(1)-C(1)-B(7)
N(1)-C(1)-B(6)
N(1)-C(1)-B(5)
B(6)-C(1)-B(5)
C(2)-N(1)-H(1)
N(21)-C(21)-Rh(1)
N(1)-C(1)-B(2)
B(7)-C(1)-B(6)
B(7)-C(1)-B(5)
C(1)-N(1)-C(2)
N(11)-C(11)-Rh(1)
C(21)-N(21)-C(22)
B(7)-C(1)-B(2)
B(2)-C(1)-B(6)
B(2)-C(1)-B(5)
C(1)-N(1)-H(1)
C(11)-N(11)-C(12)
177.7(2)
176.4(2)
yellow upon passage of a stream of CO gas, and formation of
7c was suggested by the appearance of a strong CO band at
2076 cm-1 in the IR spectrum. Removal of solvent, however,
regenerated 1a. A similar reversible formation of a CO adduct
has been observed on treatment of solutions of the 16-electron
complex [RhCl(PPh3)(η5-7,9-C2B9H11)] with CO.7
Preparation of the rhodium compounds 1 directly from [RhX-
(PPh3)3] and nido-7-NH2But-7-CB10H12 raised the possibility
of synthesizing cobalt analogs. For a reaction to occur be-
tween nido-7-NH2But-7-CB10H12 and [CoCl(PPh3)3] it was
necessary to heat these reagents for several hours in toluene at
reflux. Even under these forcing conditions the yield of
product, a deep red crystalline complex, was low. It became
apparent immediately from NMR spectra that although this
product was diamagnetic it was not an analog of 1b. Its true
nature was only established by an X-ray diffraction study. There
were two independent molecules in the asymmetric unit, and
results for one are given in Table 7, with the molecule shown
in Figure 4.
Figure 2. Molecular structure of [Rh(CNBut)2(PPh3)(η5-7-NHBut-7-
CB10H10)] (3), showing the crystallographic labeling scheme. Thermal
ellipsoids are at the 40% probability level, and hydrogen atoms are
omitted for clarity.
It is evident that the molecule is an arene(carborane)cobalt
complex [Co(η6-C6H5Me)(η5-7-NHBut-7-CB10H10)] (8) in which
of the less sterically demanding PMe3 (cone angle 118°), with
the phosphine in excess, gave the 18-electron complex [RhCl-
(PMe3)2(η5-7-NH2But-7-CB10H10)] (6). It is interesting that the
reaction with PMe3 did not afford a product containing the η5-
7-NHBut-7-CB10H10 ligand as occurs in the formation of 3. Data
fully characterizing complexes 5 and 6 are given in Tables 1-3.
The reaction between 1a and NC5H4Me-4 afforded the 18-
electron complex [RhBr(NC5H4Me-4)(PPh3)(η5-7-NH2But-7-
CB10H10)] (7a), data for which are given in Tables 1-3.
Treatment of 1a with thf (tetrahydrofuran) gave [RhBr(thf)-
(PPh3)(η5-7-NH2But-7-CB10H10)] (7b). However, although mi-
croanalytical data were obtained for this complex (Table 1), it
readily dissociates in solution and satisfactory 13C{1H}, 31P-
{1H}, and 11B{1H} NMR spectra were not measured.
the cobalt atom attains an 18-electron valence shell, formally
receiving 6 electrons from the toluene ligand and 3 from the
nido-7-NHBut-7-CB10H10 cage. Although the H atom bonded
to N(1) was not located in the X-ray diffraction pattern, its
It was not possible to isolate an 18-electron complex [RhBr-
(CO)(PPh3)(η5-7-NH2But-7-CB10H10)] (7c) as a solid by treating
1a with CO. However, red CH2Cl2 solutions of 1a turned
1
presence was revealed in the H NMR spectrum as a broad
resonance at δ 2.58 corresponding in intensity to a single proton.
The C(11)-N(1) bond length [1.415(5) Å] may be compared
(12) Tolman, C. A. Chem. ReV. 1977, 77, 313.

2972 Inorganic Chemistry, Vol. 35, No. 10, 1996
Jeffery et al.
Table 6. Selected Internuclear Distances (Å) and Angles (deg) for [Rh(CNBut)(PPh3)(η5-7-NHBut-7-CB10H10)] (4) with Estimated Standard
Deviations in Parentheses
Rh-C(6)
1.998(3)
2.204(4)
1.710(4)
1.750(5)
1.806(5)
1.812(5)
1.784(5)
1.778(5)
1.778(5)
1.453(5)
1.380(11)
Rh-C(1)
2.103(3)
2.218(3)
1.716(4)
1.782(5)
1.845(5)
1.757(5)
1.785(5)
1.791(5)
1.503(4)
1.47(2)
Rh-B(5)
2.171(3)
2.3542(10)
1.747(4)
1.850(5)
1.781(5)
1.783(5)
1.771(5)
1.780(5)
0.83(4)
Rh-B(2)
2.200(3)
1.413(4)
1.786(4)
1.790(5)
1.798(5)
1.781(5)
1.783(5)
1.781(5)
1.152(4)
1.673(13)
Rh-B(3)
Rh-B(4)
Rh-P
C(1)-N(1)
C(1)-B(5)
B(3)-B(9)
B(4)-B(10)
B(6)-B(11)
B(7)-B(11)
B(9)-B(11)
C(6)-N(7)
C(7)-C(10)
C(1)-B(6)
B(2)-B(8)
B(3)-B(8)
B(4)-B(5)
B(6)-B(7)
B(8)-B(11)
B(10)-B(11)
N(7)-C(7)
C(7)-C(8A)a
C(1)-B(7)
B(2)-B(7)
B(3)-B(4)
B(5)-B(10)
B(6)-B(10)
B(8)-B(9)
N(1)-C(2)
C(7)-C(8)
C(7)-C(9A)
C(1)-B(2)
B(2)-B(3)
B(4)-B(9)
B(5)-B(6)
B(7)-B(8)
B(9)-B(10)
N(1)-H(1)
C(7)-C(9)
C(7)-C(10A)
1.371(11)
1.460(14)
1.675(14)
C(6)-Rh-C(1)
C(6)-Rh-B(2)
C(6)-Rh-B(3)
B(2)-Rh-B(3)
B(5)-Rh-B(4)
C(6)-Rh-P
123.96(12)
C(6)-Rh-B(5)
C(1)-Rh-B(2)
C(1)-Rh-B(3)
C(6)-Rh-B(4)
B(2)-Rh-B(4)
C(1)-Rh-P
172.89(12)
C(1)-Rh-B(5)
49.37(12)
85.71(13)
84.78(14)
82.85(12)
49.31(13)
98.55(9)
89.69(9)
112(2)
87.38(13)
92.01(14)
49.68(14)
48.76(13)
88.54(9)
168.84(10)
129.9(3)
47.85(12)
82.46(13)
132.24(14)
85.38(13)
141.34(8)
120.16(10)
109(2)
176.5(4)
122.8(12)
100.3(5)
B(5)-Rh-B(2)
B(5)-Rh-B(3)
C(1)-Rh-B(4)
B(3)-Rh-B(4)
B(5)-Rh-P
B(2)-Rh-P
B(3)-Rh-P
B(4)-Rh-P
C(1)-N(1)-C(2)
N(7)-C(6)-Rh
H(1)-N(1)-C(1)
C(6)-N(7)-C(7)
C(9)-C(7)-C(8)
N(7)-C(7)-C(10)
C(10A)-C(7)-C(9A)
C(2)-N(1)-H(1)
C(9)-C(7)-N(7)
N(7)-C(7)-C(8)
C(8)-C(7)-C(10)
176.4(3)
114.8(8)
109.4(9)
102.5(11)
C(8A)-C(7)-C(10A)
C(9)-C(7)-C(10)
125.7(11)
103.2(11)
107.1(9)
C(8A)-C(7)-C(9A)
102.6(11)
a Disordered component of the CNBut ligand (see Experimental Section).
Figure 4. Molecular structure of [Co(η6-C6H5Me)(η5-7-NHBut-7-
CB10H10)] (8), showing the crystallographic labeling scheme. Thermal
ellipsoids are at the 40% probability level, and hydrogen atoms are
omitted for clarity.
Figure 3. Molecular structure of [Rh(CNBut)(PPh3)(η5-7-NHBut-7-
CB10H10)] (4), showing the crystallographic labeling scheme. Thermal
ellipsoids are at the 40% probability level, and hydrogen atoms are
omitted for clarity.
treating Na[Co(η5-C5H5)(η5-CB10H11)] with sodium naphthalide
in tetrahydrofuran, followed by addition of NaC5H5 and NiBr2
with air oxidation of the mixture. The latter was prepared in
ca. 6% yield by reacting nido-7-CH(SiMe3)2-9-SMe2-7-CB10H11
in toluene with cobalt vapor. Its structure was determined by
X-ray diffraction. The connectivities between the cobalt atom
with the corresponding C-N distances in 3 [1.438(3) Å] and 4
[1.413(4) Å], all three being perceptibly shorter than that [1.508-
(2) Å] in nido-7-NH2But-7-CB10H12.11
In addition to resonances due to the C6H5Me and But groups,
the 13C{1H} NMR spectrum of 8 displayed a broad weak peak
at δ 121.6, the band profile being typical of that for a cage-
carbon nucleus. The chemical shift may be compared with the
corresponding cage-carbon signals in the 13C{1H} NMR spectra
of 3 (δ 106.5) and 4 (δ 118.7), which also contain the η5-7-
NHBut-CB10H10 ligand. Noteworthy, the resonances for the
cage-carbons in the species having the charge-compensated η5-
7-NH2But-7-CB10H10 ligand are appreciably more shielded
(Table 2).1b
and the atoms of the CBBBB pentagonal ring ranged from 2.07-
(1) to 2.143(9) Å with the longest distance being to the carbon
atom.14 These data compare well with those for 8 in which the
connectivities between the metal atom and the CB4 atoms of
the cage are 2.069(5)-2.138(4) Å, with again the longest being
to the ring carbon. The cobalt-carbon distances involved in
attachment of the η6-C6H5Me ligand in the two molecules are
also very similar being in the range 2.126(4)-2.175(4) Å for 8
and 2.10(1)-2.17(1) Å for [Co(η6-C6H5Me)(η5-7-CH(SiMe3)2-
7-CB10H10)].
As far as we are aware, only two species structurally related
to 8 have been reported: [Co(η6-C10H10)(CB10H11)]13 and
[Co(η6-C6H5Me)(η5-7-CH(SiMe3)2-7-CB10H10)].14 The former
was obtained in ca. 9% yield as an unexpected product of
Conclusions
It has been shown that the complexes 1 can be conveniently
obtained directly from nido-7-NH2But-7-CB10H12 and [RhX-
(PPh3)3], and that these species provide a convenient entry route
to several other monocarbon rhodacarborane complexes in which
(13) Salentine, C. G.; Hawthorne, M. F. J. Am. Chem. Soc. 1975, 97,
6382.
(14) Quintana, W.; Ernest, R. L.; Carroll, P. J.; Sneddon, L. G. Organo-
metallics 1988, 7, 166.

Synthesis of Monocarbollide Complexes of Rhodium
Inorganic Chemistry, Vol. 35, No. 10, 1996 2973
Table 7. Selected Internuclear Distances (Å) and Angles (deg) for One of the Crystallographically Independent Molecules of
[Co(η6-C6H5Me)(η5-7-NHBut-7-CB10H10)] (8) with Estimated Standard Deviations in Parentheses
Co(1)-C(11)
Co(1)-B(15)
Co(1)-C(124)
C(11)-B(17)
B(12)-B(18)
B(13)-B(19)
B(14)-B(15)
B(16)-B(111)
B(18)-B(111)
B(110)-B(111)
C(130)-C(132)
C(122)-C(123)
2.138(4)
2.086(5)
2.168(5)
1.716(6)
1.766(6)
1.773(6)
1.809(6)
1.765(7)
1.782(7)
1.770(7)
1.535(5)
1.385(7)
Co(1)-B(12)
Co(1)-C(121)
Co(1)-C(125)
C(11)-B(15)
B(12)-B(17)
B(13)-B(14)
B(15)-B(110)
B(16)-B(110)
B(18)-B(19)
N(1)-C(130)
C(121)-C(122)
C(123)-C(124)
2.069(5)
2.175(4)
2.143(4)
1.719(5)
1.798(6)
1.801(7)
1.769(7)
1.770(7)
1.783(7)
1.480(5)
1.387(6)
1.365(8)
Co(1)-B(13)
Co(1)-C(122)
Co(1)-C(126)
C(11)-B(16)
B(12)-B(13)
B(14)-B(110)
B(15)-B(16)
B(17)-B(18)
B(19)-B(111)
C(130)-C(133)
C(121)-C(126)
C(124)-C(125)
2.100(4)
2.143(4)
2.126(4)
1.723(5)
1.813(6)
1.772(7)
1.775(6)
1.775(7)
1.759(7)
1.524(5)
1.395(6)
1.386(7)
Co(1)-B(14)
Co(1)-C(123)
C(11)-N(1)
2.104(5)
2.158(5)
1.415(5)
1.748(5)
1.771(7)
1.774(7)
1.757(7)
1.784(7)
1.777(7)
1.525(5)
1.510(6)
1.393(7)
C(11)-B(12)
B(13)-B(18)
B(14)-B(19)
B(16)-B(17)
B(17)-B(111)
B(19)-B(110)
C(130)-C(131)
C(121)-C(127)
C(125)-C(126)
B(12)-Co(1)-B(15)
B(12)-Co(1)-B(14)
85.7(2)
87.8(2)
100.8(2)
126.4(2)
86.0(2)
96.5(2)
164.4(2)
165.4(2)
92.0(2)
80.1(2)
155.5(2)
113.6(2)
118.2(2)
149.1(2)
37.5(2)
128.1(2)
97.2(2)
68.4(2)
80.1(2)
B(12)-Co(1)-B(13)
B(15)-Co(1)-B(14)
B(15)-Co(1)-C(126)
B(12)-Co(1)-C(11)
B(14)-Co(1)-C(11)
B(15)-Co(1)-C(125)
C(126)-Co(1)-C(125)
B(15)-Co(1)-C(122)
C(126)-Co(1)-C(122)
B(12)-Co(1)-C(123)
B(14)-Co(1)-C(123)
C(125)-Co(1)-C(123)
B(15)-Co(1)-C(124)
C(126)-Co(1)-C(124)
C(122)-Co(1)-C(124)
B(15)-Co(1)-C(121)
C(126)-Co(1)-C(121)
C(122)-Co(1)-C(121)
C(11)-N(1)-C(130)
51.6(2)
51.2(2)
173.2(2)
49.1(2)
85.5(2)
143.9(2)
38.1(2)
105.5(2)
67.8(2)
152.8(2)
113.7(2)
67.3(2)
110.9(2)
68.0(2)
67.1(2)
135.8(2)
37.8(2)
37.5(2)
130.5(3)
B(15)-Co(1)-B(13)
87.4(2)
50.7(2)
95.0(2)
48.0(2)
138.4(2)
122.0(2)
108.7(2)
118.5(2)
145.4(2)
95.0(2)
80.2(2)
37.6(2)
159.4(2)
99.0(2)
36.8(2)
93.6(2)
176.2(2)
67.8(2)
B(13)-Co(1)-B(14)
B(13)-Co(1)-C(126)
B(15)-Co(1)-C(11)
C(126)-Co(1)-C(11)
B(13)-Co(1)-C(125)
C(11)-Co(1)-C(125)
B(13)-Co(1)-C(122)
C(11)-Co(1)-C(122)
B(15)-Co(1)-C(123)
C(126)-Co(1)-C(123)
C(122)-Co(1)-C(123)
B(13)-Co(1)-C(124)
C(11)-Co(1)-C(124)
C(123)-Co(1)-C(124)
B(13)-Co(1)-C(121)
C(11)-Co(1)-C(121)
C(123)-Co(1)-C(121)
B(12)-Co(1)-C(126)
B(14)-Co(1)-C(126)
B(13)-Co(1)-C(11)
B(12)-Co(1)-C(125)
B(14)-Co(1)-C(125)
B(12)-Co(1)-C(122)
B(14)-Co(1)-C(122)
C(125)-Co(1)-C(122)
B(13)-Co(1)-C(123)
C(11)-Co(1)-C(123)
B(12)-Co(1)-C(124)
B(14)-Co(1)-C(124)
C(125)-Co(1)-C(124)
B(12)-Co(1)-C(121)
B(14)-Co(1)-C(121)
C(125)-Co(1)-C(121)
C(124)-Co(1)-C(121)
Table 8. Crystallographic Data
1a‚CH2Cl2
3
4
8
formula
Mr
T/K
C24H38B10BrCl2NPRh
733.34
293
C33H53B10N3PRh
733.76
173
C28H44B10N2PRh
650.63
173
C12H28B10NCo
353.38
293
crystal system
space group
a (Å)
b (Å)
c (Å)
monoclinic
P21/c
12.937(3)
18.101(4)
14.695(4)
monoclinic
P21/c
10.533(2)
19.110(4)
19.707(4)
triclinic
P1h
9.840(3)
10.809(3)
17.287(3)
88.49(2)
monoclinic
P21/c
16.332(5)
10.397(2)
22.186(6)
R (deg)
â (deg)
γ (deg)
V (Å3)
Z
104.21(2)
105.413(9)
84.57(2)
102.94(2)
69.809(14)
1717.8(8)
2
1.258
0.565
3335.8(14)
4
1.460
1.936
1472
3824.0(14)
4
1.275
0.516
1528
3671(2)
8
1.279
0.926
d
calcd/g cm-3
µ(Mo KR) / mm-1
F(000)/e
672
1472
crystal dimensions (mm)
crystal color, shape
reflcns measured
independent reflcns
2θ range (deg)
0.25 × 0.30 × 0.30
0.45 × 0.1 × 0.1
yellow needle
17402
6720
4.0-50.0
full-matrix least squares
on all F2 data
wR2 ) 0.104a
(R1 ) 0.039)b
a ) 0.0602; b ) 2.0925a
1.079
0.60 × 0.40 × 0.40
red prism
7830
0.15 × 0.20 × 0.25
red prism
red prism
14659
5849
5.0-50.0
full-matrix least squares
on all F2 data
wR2 ) 0.131a
(R1 ) 0.051)b
a ) 0.0394; b ) 11.54a
1.120
13397
5221
3.0-46.5
full-matrix least squares
on all F2 data
wR2 ) 0.115a
(R1 ) 0.052)b
a ) 0.0265; b ) 3.6239a
1.198
5836
5.0-50.0
full-matrix least squares
on all F2 data
wR2 ) 0.067a
(R1 ) 0.027)b
a ) 0.0205; b ) 3.3801a
1.101
refinement method
final residuals
weighting factors
goodness of fit on F2
final electron density diff
features (max/min)/e Å-3
0.65, -1.02
0.70, -1.14
0.29, -0.41
0.21, -0.23
2
2
2
a Structure was refined on Fo2 using all data: wR2 ) [∑[w(Fo2 - Fc2)2]/∑w(Fo )2]1/2, where w-1 ) [σ2(Fo ) + (aP)2 + bP] and P ) [max(Fo , 0)
+ 2Fc2]/3. b The value in parentheses is given for comparison with refinements based on Fo with a typical threshold of F g 4σ(F) and Rl ) ∑||Fo|
2
- |Fc||/∑|Fo| and w-1 ) [σ2(Fo) + gFo ].
the metal adopts either 16- or 18-electron configurations in the
valence shell. Reactions with CNBut in which neutral charge-
compensated carbon-substituted closo-1-NH2But-2,1-RhCB10H10
frameworks are transformed into polyhedra with closo-1-NHBut-
2,1-RhCB10H10 cage structures are without precedent. The
synthesis of the cobalt complex 8 is novel and must at some
stage in the reaction involve deprotonation of an η5-7-NH2But-
7-CB10H10 four-electron donor ligand into a three-electron donor
η5-7-NHBut-7-CB10H10 group. Together the three compounds
[Co(η6-C10H10)(CB10H11)],13 [Co(η6-C6H5Me)(η5-7-CH(SiMe3)2-

2974 Inorganic Chemistry, Vol. 35, No. 10, 1996
Jeffery et al.
Table 9. Atomic Positional Parameters (Fractional Coordinates ×
104) and Equivalent Isotropic Displacement Parameters (Å2 × 103)
for the Atoms of 1a
Table 10. Atomic Positional Parameters (Fractional Coordinates ×
104) and Equivalent Isotropic Displacement Parameters (Å2 × 103)
for the Atoms of 3
atom
x
y
z
U(eq)a
atom
x
y
z
U(eq)a
Rh
Br
P
2809(1)
2711(1)
3492(1)
2577(5)
1570(5)
879(6)
319(1)
1666(1)
39(1)
217(3)
486(3)
621(4)
486(5)
217(5)
66(4)
-885(3)
-1446(4)
-2171(4)
-2332(4)
-1787(4)
-1058(4)
654(3)
2824(1)
2387(1)
1534(1)
400(4)
35(1)
65(1)
38(1)
45(1)
55(2)
72(2)
80(3)
79(2)
61(2)
41(1)
54(2)
65(2)
65(2)
63(2)
55(2)
39(1)
46(1)
56(2)
63(2)
61(2)
49(1)
40(1)
42(2)
41(1)
43(2)
44(2)
45(2)
46(2)
50(2)
49(2)
45(2)
52(2)
51(1)
71(2)
96(3)
86(2)
88(3)
168(8)
163(2)
203(3)
Rh(1)
B(2)
B(3)
B(4)
B(5)
B(6)
B(7)
B(8)
B(9)
B(10)
B(11)
C(1)
N(1)
C(2)
C(3)
C(4)
C(5)
C(11)
N(11)
C(12)
C(13)
C(14)
C(15)
C(21)
N(21)
C(22)
C(23)
C(24)
C(25)
P
C(31)
C(32)
C(33)
C(34)
C(35)
C(36)
C(41)
C(42)
C(43)
C(44)
C(45)
C(46)
C(51)
C(52)
C(53)
C(54)
C(55)
C(56)
7691(1)
5734(2)
6008(2)
7584(2)
8180(3)
7037(3)
5521(3)
4928(3)
6049(2)
7384(3)
5741(3)
6986(2)
7416(2)
6862(2)
7710(3)
6926(3)
5437(3)
9332(2)
10254(2)
11447(2)
12475(3)
11077(3)
11905(3)
6928(2)
6510(2)
6087(2)
7193(3)
5847(3)
4833(2)
8687(1)
8015(2)
6730(2)
6238(3)
7003(3)
8265(3)
8779(3)
8790(2)
8259(3)
8448(3)
9182(3)
9699(3)
9505(2)
10431(2)
11289(2)
12588(2)
13038(3)
12204(2)
10902(2)
8429(1)
7877(1)
8463(1)
8189(1)
7466(1)
6759(1)
7010(1)
7732(1)
7916(1)
7307(1)
7041(1)
7266(1)
6862(1)
6852(1)
6328(1)
7561(1)
6592(1)
8229(1)
8075(1)
7907(1)
7635(2)
7369(2)
8587(2)
8977(1)
9264(1)
9584(1)
9472(2)
10353(1)
9214(1)
9463(1)
9916(1)
10170(1)
10535(1)
10644(1)
10393(2)
10028(1)
10171(1)
10833(1)
11361(2)
11237(2)
10579(2)
10048(2)
9351(1)
9923(1)
9851(2)
9221(2)
8650(2)
8712(1)
2324(1)
2069(1)
1374(1)
1208(1)
1824(1)
1564(1)
1710(1)
1165(1)
651(1)
17(1)
21(1)
20(1)
20(1)
21(1)
23(1)
23(1)
23(1)
22(1)
23(1)
24(1)
20(1)
25(1)
27(1)
37(1)
33(1)
34(1)
23(1)
28(1)
35(1)
65(1)
67(1)
46(1)
21(1)
23(1)
25(1)
38(1)
39(1)
36(1)
20(1)
22(1)
26(1)
32(1)
38(1)
41(1)
32(1)
23(1)
34(1)
44(1)
43(1)
43(1)
34(1)
23(1)
29(1)
36(1)
37(1)
36(1)
30(1)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
C(31)
C(32)
C(33)
C(34)
C(35)
C(36)
C(1)
B(2)
B(3)
B(4)
B(5)
B(6)
B(7)
B(8)
B(9)
340(5)
-531(5)
-1337(5)
-1280(5)
-428(4)
1398(4)
1045(4)
1000(5)
1292(5)
1622(5)
1671(4)
1651(4)
2490(4)
2641(4)
1950(5)
1125(5)
959(4)
4118(4)
4270(4)
3496(4)
2777(5)
3163(5)
4683(5)
3789(5)
3556(5)
4358(5)
5055(4)
4731(5)
4239(3)
5140(5)
5807(6)
5550(6)
4770(6)
-2066(14)
-3084(3)
-1147(4)
1213(7)
2212(7)
2900(6)
3984(5)
3268(5)
3610(7)
4678(7)
5395(6)
5058(5)
4630(4)
5399(5)
6254(5)
6335(6)
5570(6)
4720(5)
2212(4)
3459(5)
3370(5)
2026(5)
1342(5)
3318(6)
2410(6)
1166(6)
1282(6)
2609(6)
1959(6)
2017(4)
2320(7)
1643(8)
3558(7)
2023(8)
291(11)
641(3)
921(1)
847(1)
2283(1)
2918(1)
3537(1)
4049(1)
3901(1)
3340(1)
3106(1)
3542(1)
4101(1)
3751(2)
4582(2)
4497(2)
2992(1)
3401(1)
3978(1)
4646(1)
3803(2)
4025(1)
2065(1)
1229(1)
1054(1)
431(1)
652(3)
1127(4)
1629(4)
1647(4)
1159(3)
473(3)
81(4)
-731(3)
-751(4)
57(4)
-823(4)
-1330(4)
-841(4)
-105(4)
-89(4)
-943(4)
1273(3)
1746(4)
1522(5)
1690(5)
2531(4)
-2144(7)
-1816(3)
-1598(4)
B(10)
B(11)
N(1)
C(2)
C(3)
C(4)
-26(1)
137(1)
761(1)
C(5)
2712(1)
2541(1)
3042(2)
3719(2)
3901(1)
3407(1)
2094(1)
2252(1)
2229(1)
2048(1)
1899(1)
1923(1)
C(60)
Cl(1)
Cl(2)
771(5)
a Equivalent isotropic U defined as one-third of the trace of the
orthogonalized Uij tensor.
7-CB10H10)],14 and 8 form a family of complexes where
monocarbon ligands, formally [RCB10H10]3-, are bound to Co3+
.
Experimental Section
a Equivalent isotropic U defined as one-third of the trace of the
orthogonalized Uij tensor.
General Considerations. 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 fraction of boiling point
40-60 °C. Chromatography columns (ca. 60 cm long and 1 cm in
diameter) were packed with silica gel (Aldrich, 70-230 mesh). The
NMR measurements were recorded at the following frequencies: 1H
at 360.13, 13C at 90.56, 11B at 115.55, and 31P at 145.78 MHz. The
reagents [7-NH2But-nido-7-CB10H12],1b,15 [RhX(PPh3)3] (X ) Br, Cl),16
and [CoCl(PPh3)3]17 were made by procedures previously described.
Syntheses of the Compounds [RhX(PPh3)(η5-7-NH2But-7-CB10H10)]
(1, X ) Br, Cl). (i) A mixture of the compounds [RhBr(PPh3)3] (0.97
g, 1.0 mmol) and nido-7-NH2But-7-CB10H12 (0.20 g, 1.0 mmol) was
refluxed in toluene (20 mL) for 3 h. Solvent was removed in Vacuo,
and the residue was dissolved in CH2Cl2 (5 mL) and then chromato-
graphed. Elution with CH2Cl2-light petroleum (3:1) removed a deep
red fraction. The solvent was removed in Vacuo and the residue
crystallized from toluene (10 mL) to give red microcrystals of [RhBr-
(PPh3)(η5-7-NH2But-7-CB10H10)] (1a) (0.36 g).
(ii) By use of a similar procedure [RhCl(PPh3)3] (0.93 g, 1.0 mmol)
and nido-7-NH2But-7-CB10H12 (0.20 g, 1.0 mmol) gave red microc-
rystals of [RhCl(PPh3)(η5-7-NH2But-7-CB10H10)] (1b) (0.35 g).
Reactions of the Complexes [RhX(PPh3)(η5-7-NH2But-7-CB10H10)]
(X ) Br or Cl) with CNBut. (i) Compound 1a (0.20 g, 0.30 mmol)
was dissolved in CH2Cl2 (15 mL) and the solution maintained at -20
°C. A solution of CNBut (0.025 g, 0.30 mmol) in CH2Cl2 (5 mL) was
added dropwise and then the mixture allowed to warm gradually to
room temperature. Solvent was removed in Vacuo, and crystallization
from CH2Cl2-light petroleum (1:8, 10 mL) afforded orange micro-
crystals of [RhBr(CNBut)(PPh3)(η5-7-NH2But-7-CB10H10)] (2a) (0.19 g).
(ii) Similarly 1b (0.13 g, 0.21 mmol) and CNBut (0.017 g, 0.21
mmol) gave orange microcrystals of [RhCl(CNBut)(PPh3)(η5-7-NH2-
But-7-CB10H10)] (2b) (0.12 g).
(iii) Compound 1a (0.16 g, 0.26 mmol) was dissolved in CH2Cl2 (5
mL). To this solution was added CNBut (0.04 g, 0.52 mmol) in CH2-
Cl2 (5 mL), causing a color change from red to yellow. Removal of
solvent in Vacuo followed by crystallization from CH2Cl2-light
petroleum (1:6, 15 mL) afforded yellow microcrystals of [Rh(CNBut)2-
(PPh3)(η5-7-NHBut-7-CB10H10)] (3) (0.11 g).
(15) Hyath, D. E.; Owen, D. A.; Todd, L. Inorg. Chem. 1966, 5, 1749.
(16) Osborn, J. A.; Wilkinson, G. Inorg. Synth. 1967, 10, 67.
(17) Wakatsuki, Y.; Yamazaki, H. Inorg. Synth. 1989, 26, 189.

Synthesis of Monocarbollide Complexes of Rhodium
Inorganic Chemistry, Vol. 35, No. 10, 1996 2975
Table 11. Atomic Positional Parameters (Fractional Coordinates ×
104) and Equivalent Isotropic Displacement Parameters (Å2 × 103)
for the Atoms of 4
Table 12. Atomic Positional Parameters (Fractional Coordinates ×
104) and Equivalent Isotropic Displacement Parameters (Å2 × 103)
for the Atoms of 8
atom
Rh
P
C(1)
B(2)
B(3)
B(4)
B(5)
B(6)
B(7)
B(8)
B(9)
B(10)
B(11)
N(1)
C(2)
C(3)
C(4)
C(5)
C(6)
N(7)
C(7)
C(8)
C(9)
C(10)
C(8A)
C(9A)
C(10A)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
C(31)
C(32)
C(33)
C(34)
C(35)
C(36)
x
y
z
U(eq)a
atom
x
y
z
U(eq)a
9498(1)
8983(1)
9880(3)
9685(4)
7948(4)
7192(4)
8458(4)
8607(4)
9322(4)
8088(4)
6587(4)
6905(4)
7413(4)
11203(3)
12728(3)
12813(5)
13234(5)
13661(4)
10533(4)
11085(4)
11737(7)
12337(33)
11007(18)
13232(17)
12977(14)
10421(15)
11583(33)
10584(3)
11933(4)
13184(4)
13112(4)
11785(4)
10506(4)
8451(3)
9188(4)
8702(5)
7496(5)
6769(5)
7233(4)
7556(3)
6750(4)
5718(4)
5507(5)
6359(5)
7353(4)
6817(1)
9109(1)
5154(3)
4770(3)
6027(4)
7122(3)
6567(3)
4925(3)
3843(3)
4386(4)
5785(4)
6108(4)
4454(4)
5250(2)
4286(3)
3000(5)
4103(8)
4890(4)
6804(3)
6763(3)
6799(5)
5460(17)
7871(19)
7103(29)
5725(16)
6616(24)
8176(16)
9510(3)
8669(3)
8922(4)
9996(4)
10827(4)
10589(3)
9985(3)
10768(3)
11482(4)
11416(4)
10629(4)
9913(4)
10062(3)
11378(3)
12090(4)
11496(4)
10198(4)
9474(4)
7355(1)
7278(1)
6650(2)
7633(2)
8010(2)
7203(2)
6347(2)
6117(2)
6892(2)
7730(2)
7476(2)
6472(2)
6806(2)
6309(2)
6309(2)
5921(4)
7111(3)
5792(2)
8297(2)
8861(2)
9576(3)
9878(14)
10045(10)
9221(8)
9661(9)
10208(6)
9692(14)
7479(2)
7157(2)
7268(3)
7708(3)
8032(2)
7917(2)
6372(2)
6019(2)
5356(2)
5043(2)
5384(2)
6045(2)
8011(2)
7900(2)
8477(2)
9175(3)
9303(3)
8713(2)
23(1)
24(1)
23(1)
28(1)
32(1)
30(1)
27(1)
29(1)
28(1)
33(1)
34(1)
32(1)
33(1)
26(1)
37(1)
88(2)
101(3)
47(1)
33(1)
42(1)
81(2)
203(19)
131(11)
168(11)
95(7)
135(7)
199(18)
28(1)
38(1)
52(1)
53(1)
45(1)
35(1)
29(1)
37(1)
47(1)
51(1)
50(1)
42(1)
29(1)
36(1)
44(1)
55(1)
57(1)
48(1)
Co(1)
C(11)
B(12)
B(13)
B(14)
B(15)
B(16)
B(17)
B(18)
B(19)
B(110)
B(111)
N(1)
C(130)
C(131)
C(132)
C(133)
C(121)
C(122)
C(123)
C(124)
C(125)
C(126)
C(127)
Co(2)
4725(1)
5799(2)
5786(3)
5577(3)
5403(3)
5523(3)
6583(3)
6749(3)
6617(3)
6388(3)
6343(3)
7104(3)
5522(2)
5846(2)
5915(3)
6693(3)
5193(3)
3631(3)
3554(3)
3614(3)
3760(3)
3868(3)
3809(3)
3546(3)
281(1)
-795(2)
-590(3)
-458(3)
-543(3)
-714(3)
-1630(3)
-1431(3)
-1411(3)
-1565(3)
-1712(3)
-2127(3)
-514(2)
-813(3)
-1682(3)
-821(3)
-171(3)
1385(2)
1258(2)
1202(3)
1256(3)
1347(3)
1408(2)
1472(3)
870(1)
2091(3)
1037(4)
-572(4)
-422(4)
1266(4)
1707(5)
1583(5)
-54(5)
3560(1)
3656(2)
4267(2)
3955(2)
3127(2)
2969(2)
3281(2)
4089(2)
4274(2)
3570(2)
2954(2)
3655(2)
3648(2)
4062(2)
4740(2)
3963(2)
3881(2)
3526(2)
2969(2)
2948(3)
3482(4)
4049(3)
4068(2)
3544(3)
1487(1)
1324(2)
2019(2)
1871(2)
1050(2)
730(2)
45(1)
42(1)
46(1)
49(1)
53(1)
48(1)
51(1)
51(1)
54(1)
56(1)
56(1)
61(1)
47(1)
49(1)
61(1)
69(1)
67(1)
60(1)
70(1)
82(2)
87(2)
83(2)
68(1)
98(2)
42(1)
41(1)
44(1)
50(1)
49(1)
45(1)
47(1)
52(1)
54(1)
49(1)
48(1)
54(1)
46(1)
50(1)
66(1)
65(1)
70(1)
54(1)
60(1)
76(2)
80(2)
73(1)
61(1)
78(2)
-947(5)
162(5)
340(5)
3382(3)
4471(4)
4127(4)
4956(4)
5532(4)
-344(4)
305(5)
1632(6)
2332(5)
1717(6)
381(5)
-1789(5)
9523(1)
8301(3)
9113(4)
10812(4)
10965(4)
9362(4)
8673(4)
10219(5)
11339(5)
10442(4)
8813(5)
10040(5)
7011(3)
5924(4)
5447(4)
6257(4)
4858(4)
10748(4)
10010(5)
8669(6)
8052(5)
8779(5)
10109(5)
12187(4)
C(21)
B(22)
B(23)
B(24)
B(25)
B(26)
B(27)
B(28)
1653(2)
1991(2)
1384(2)
680(2)
B(29)
B(210)
B(211)
N(2)
852(2)
1253(2)
1345(1)
923(2)
978(2)
249(2)
1134(2)
1568(2)
1032(2)
1054(3)
1612(3)
2149(2)
2127(2)
1557(2)
C(230)
C(231)
C(232)
C(233)
C(221)
C(222)
C(223)
C(224)
C(225)
C(226)
C(227)
a Equivalent isotropic U defined as one-third of the trace of the
orthogonalized Uij tensor.
a Equivalent isotropic U defined as one-third of the trace of the
orthogonalized Uij tensor.
(iv) Similarly 1b (0.10 g, 0.16 mmol) and CNBut (0.026 g, 0.32
mmol) gave 3 (0.08 g, yield 66%).
(v) A solution of 1a (0.17 g, 0.26 mmol) in CH2Cl2 (20 mL) was
treated with CNBut (0.021 g, 0.26 mmol) and the mixture stirred for 1
h. Solvent was then reduced in Vacuo to a volume of 3 mL and the
solution chromatographed. Elution with CH2Cl2-light petroleum (4:
1) removed a red fraction. Solvent was removed in Vacuo, and
crystallization of the residue from CH2Cl2-light petroleum (1:7, 15
mL) gave red microcrystals of [Rh(CNBut)(PPh3)(η5-7-NHBut-7-
CB10H10)] (4) (0.14 g).
(vi) Similarly, a mixture of 1b (0.20 g, 0.33 mmol) and CNBut (0.027
g, 0.33 mmol) in CH2Cl2 (25 mL) gave 4 (0.13 g, yield 54%).
(vii) By use of the same procedure, compound 4 (0.05 g, 0.08 mmol)
and CNBut (0.006 g, 0.08 mmol) in CH2Cl2 (5 mL) afforded
microcrystals of 3 (0.04 g, yield 71%).
Reactions of the Compounds [RhX(PPh3)(η5-7-NH2But-7-CB10H10)]
with PR3 (R ) Me or Et). (i) A solution of compound 1a (0.08 g,
0.12 mmol) in CH2Cl2 (15 mL) was treated with PEt3 (0.02 g, 0.12
mmol) and the mixture stirred for 2 h. Solvent was then removed in
Vacuo and crystallization of the residue from CH2Cl2-light petroleum
(1:6, 10 mL) yielded red microcrystals of [RhBr(PEt3)(η5-7-NH2But-
7-CB10H10)] (5) (0.05 g).
(ii) Using a similar procedure, a mixture of compound 1b (0.06 g,
0.1 mmol) and PMe3 (0.4 mL of a 1.0 M solution in thf, 0.4 mmol)
gave orange-red microcrystals of [RhCl(PMe3)2(η5-7-NH2But-7-
CB10H10)] (6) (0.04 g).
Reactions of the Compound [RhBr(PPh3)(η5-7-NH2But-7-CB10H10)]
with 4-Picoline and thf. (i) A mixture of compound 1a (0.09 g, 0.14
mmol) and NC5H4Me-4 (0.01 g, 0.14 mmol) was stirred in CH2Cl2 (10
mL) for 6 h. Solvent was then removed in Vacuo and the residue
crystallized from benzene-light petroleum (1:5, 15 mL) to give red
microcrystals of [RhBr(PPh3)(NC5H4Me-4)(η5-7-NH2But-7-CB10H10)]
(7a) (0.09 g).
(ii) Similarly compound 1a (0.10 g, 0.14 mmol) was stirred in thf
(5 mL) for 7 h to give red microcrystals of [RhBr(thf)(PPh3)(η5-7-
NH2But-7-CB10H10)] (7b) (0.09 g).
Synthesis of the Cobalt Compound [Co(η6-C6H5Me)(η5-7-NHBut-
7-CB10H10)]. A mixture of [CoCl(PPh3)3] (0.88 g, 1.0 mmol) and nido-
7-NH2But-7-CB10H12 (0.20 g, 1.0 mmol) was refluxed in toluene (20
mL) for 6 h. Solvent was removed in Vacuo and the residue taken up
in CH2Cl2 (15 mL) and chromatographed. Elution with CH2Cl2-light

2976 Inorganic Chemistry, Vol. 35, No. 10, 1996
Jeffery et al.
petroleum (1:10) removed a deep red fraction. Evaporation of solvent
and crystallization from CH2Cl2-light petroleum (1:8, 15 mL) gave
deep red microcrystals of [Co(η6-C6H5Me)(η5-7-NHBut-7-CB10H10)] (8)
(0.15 g).
procedures. The structures were refined by full-matrix least-
squares on all F2 data using Siemens SHELXTL 5.03,18 and
with anisotropic thermal parameters for all non-hydrogen atoms.
The NH protons in 3 and 8 were located from final electron
density difference syntheses, and their positions were refined.
All other hydrogen atoms were included in calculated positions
and allowed to ride on the parent boron or carbon atoms with
isotropic thermal parameters (Uiso ) 1.2Uiso equiv of the parent
atom except for Me protons where Uiso ) 1.3Uiso equiv). For 4
the methyl groups of the CNBut ligand are disordered (1:1) over
two sites such that the two sets of methyl substituents are
staggered about the Rh-C(7) bond. For clarity only one of
the disordered components is shown in Figure 3. For 8 there
are two essentially similar crystallographically independent
molecules in the asymmetric unit. Only one of these molecules
is shown in Figure 4 and discussed in the text. Atomic
positional parameters for complexes 1a, 3, 4, and 8 are listed
in Tables 9-12. All calculations were carried out on Silicon
Graphics Iris Indigo or Indy computers.
Crystal Structure Determinations and Refinements
Crystals were grown by diffusion of light petroleum into CH2-
Cl2 solutions of the complexes.
Low-temperature data sets for 3 and 4 were collected with
the crystals mounted on glass fibers. The ambient temperature
data sets for 1a and 8 were collected with the crystals sealed in
capillary tubes. Complex 1a crystallized with a molecule of
CH2Cl2 per molecule of the complex.
Data (Table 8) were collected on a Siemens SMART CCD
area-detector three-circle diffractometer using Mo KR X-
radiation λh ) 0.71073. For three settings of φ, narrow data
“frames” were collected for 0.3° increments in ω. In all cases
1271 frames of data were collected, affording rather more than
a hemisphere of data for each complex. The substantial
redundancy in data allows empirical absorption corrections to
be applied using multiple measurements of equivalent reflec-
tions. Data frames were collected for 10-60 s per frame giving
overall data collection times of between ca. 6 and 25 h. The
data frames were integrated using SAINT,18 and the structures
were solved by conventional direct methods or heavy atom
Acknowledgment. We thank the Robert A. Welch Founda-
tion for support (Grant AA-1201).
Supporting Information Available: Complete tables of bond
lengths and angles, anisotropic thermal parameters, and hydrogen atom
parameters for 1a, 3, 4, and 8 (36 pages). Ordering information is
given on any current masthead page.
(18) Siemens X-ray Instruments, Madison, WI.
IC951550E