Inorganic Chemistry
Article
3
1
1
α-[8-{8′-2′-(p-cymene)-closo-2′,1′,8′-RuC B H }-2-H-2,2-(PPh ) -
δ: −1.4 (1B), −6.5 (2B), −9.2 (2B), −19.7 (4B). P{ H} NMR δ:
103 1
2
9
10
3 2
closo-2,1,8-RhC B H ] (2α). R 0.28. Yield 0.021 g, 0.019 mmol, 21%.
36.12 (d, 2P, J = 111.0 Hz). Rh{ H} NMR δ: −922.48 (t, J
111.0 Hz). For Rh chemical shift referencing, see a later description
=
RhP
2
9
10
f
RhP
03
1
C H B P RhRu requires: C 53.3, H 5.82. Found: C 54.5, H 6.08%.
5
0
65 18 2
1
103
H NMR δ 7.43−7.09 (m, 30H, C H ), 5.74−5.63 [m, 4H,
6
5
CH C H CH(CH ) ], 2.70 [app sept, 1H, CH C H CH(CH ) ],
3
6
4
3
2
3
6
4
3 2
2
1
.45 (br s, 1H, C1′H), 2.17 [s, 3H, CH C H CH(CH ) ], 1.31 (br s,
General Procedure for Alkene Isomerization. A J. Young NMR
tube was flushed with N and charged with 1-hexene (188 μL, 1.503
mmol) and mesitylene (internal standard, 104 μL, 0.748 mmol). A
CDCl (1 mL) solution of the catalyst precursor (0.003 mmol) was
added, and the progress of the reaction monitored by H NMR
spectroscopy. Further details are available in the SI.
General Procedure for Ketone Hydrosilylation. Acetophenone (37
μL, 0.317 mmol), diphenylsilane (74 μL, 0.399 mmol), and
mesitylene (internal standard, 22 μL, 0.158 mmol) were combined
in a J. Young NMR tube previously flushed with N . A CDCl (1 mL)
3
6
4
3 2
H, C1H), 1.23 [d, 3H, CH C H CH(CH ) ], 1.21 [d, 3H,
3
6
4
3
2
2
CH C H CH(CH ) ], −8.56 (ddd, 1H, RhH, J
= 29.8 Hz, JPH
=
3
6
4
3
2
RhH
1
1
1
2
3.7, 15.4 Hz). B{ H} NMR δ 0.2 to −8.6 multiple overlapping
3
1
resonances with maxima at 0.2, −1.7, −5.2, −8.6 (total integral 12B),
−
−
15.7 to −21.0 multiple overlapping resonances with maxima at
3
1
1
15.7, −16.5, −21.0 (total integral 6B). P{ H} NMR δ 36.95 (dd,
1
P, J = 114.9 Hz, J = 26.8 Hz), 32.65 (dd, 1P, JRhP = 109.0 Hz,
RhP PP
+
JPP = 26.8 Hz). EIMS: envelope centered on m/z 603 (M -2 × PPh ).
3
β-[8-{8′-2′-(p-cymene)-closo-2′,1′,8′-RuC B H }-2-H-2,2-(PPh ) -
2
9
10
3 2
2
3
closo-2,1,8-RhC B H ] (2β). R 0.35. Yield 0.033 g, 0.029 mmol, 33%.
2
9
10
f
solution of the catalyst precursor (0.0016 mmol) was added, and the
reagents were heated to 55 °C; the progress of the reaction was
monitored by H NMR spectroscopy. Further details are available in
C H B P RhRu requires: C 53.3, H 5.82. Found: C 53.4, H 5.86%.
5
0
65 18
2
1
H NMR δ 7.42−7.09 (m, 30H, C H ), 5.79−5.66 [m, 4H,
1
6
5
CH C H CH(CH ) ], 2.71 [app sept, 1H, CH C H CH(CH ) ],
3
6
4
3
2
3
6
4
3
2
2
1
.45 (br s, 1H, C1′H), 2.20 [s, 3H, CH C H CH(CH ) ], 1.33 (br s,
3
6
4
3
2
Crystallography. Single crystals of 1·0.5CH Cl , 2α·2CH Cl ,
3α·2.5CH Cl , and V were grown by diffusion of a DCM solution of
the appropriate compound and petrol at −20 °C. Crystals of 2β·
.5CH Cl were obtained by vapor diffusion of a DCM solution and
2
2
2
2
H, C1H), 1.24 [d, 3H, CH C H CH(CH ) ], 1.22 [d, 3H,
3
6
4
3
2
2 2
CH C H CH(CH ) ], −8.57 (ddd, 1H, RhH, J
= 30.1 Hz, JPH
=
3
6
4
3
2
RhH
1
1
1
2
3.7, 14.7 Hz). B{ H} NMR δ 0.0 to −8.5 multiple overlapping
1
2
2
resonances with maxima at 0.0, −5.1, −8.5 (total integral 12B), −15.8
petrol at −20 °C, while single crystals of 3β·2.5CH Cl were afforded
2
2
to −21.1 multiple overlapping resonances with maxima at −15.8,
by slow evaporation of a DCM solution at room temperature.
3
1
1
−
16.6, −21.1 (total integral 6B). P{ H} NMR δ 36.99 (dd, 1P, J
RhP
Diffraction data were obtained from 3α·2.5CH Cl and 3β·2.5CH Cl
on a Bruker X8 APEXII diffractometer operating with Mo Kα
radiation. Data from 1·0.5CH Cl were obtained on a Rigaku AFC12
diffractometer using Mo Kα radiation. Data from 2α·2CH Cl and 2β·
1.5CH Cl were obtained on a Rigaku 007HF diffractometer using Cu
2 2
Kα radiation. Data from V were obtained on a Bruker D8 Venture
diffractometer equipped with Mo Kα radiation. All diffraction data
were collected at 100 K except for that of V (150 K). Structures were
solved using OLEX2 by direct methods using the SHELXS or
SHELXT program and were refined by full-matrix least-squares
using SHELXL. All crystals except V contain DCM of solvation, all
of which was impossible to model satisfactorily. Crystals of 1 contain
.5DCM per molecule of 1, but this could not be modeled. In 2α
there are 2DCM per molecule of 2α, only one of which could be
modeled. Crystals of 2β have 1.5DCM per molecule, but this was not
possible to model. 3α and 3β are isomorphous, with both having
.5DCM per molecule of 3, but two of these could not be modeled
while the remaining 0.5DCM could be. In all cases the intensity
contribution of the badly disordered solvent was removed using the
BYPASS procedure implemented in OLEX2. In 1·0.5CH Cl , 2α·
2 2
2
2
2
2
=
113.0 Hz, J = 25.8 Hz), 32.62 (dd, 1P, JRhP = 109.0 Hz, J = 25.8
P
P
P
P
+
Hz). EIMS: envelope centered on m/z 603 (M -2 × PPh ).
3
2
2
α-[8-(8′-2′-Cp*-closo-2′,1′,8′-CoC B H )-2-H-2,2-(PPh ) -closo-
2
9
10
3 2
2 2
2
,1,8-RhC B H ] (3α) and β-[8-(8′-2′-Cp*-closo-2′,1′,8′-
2
9
10
n
CoC B H )-2-H-2,2-(PPh ) -closo-2,1,8-RhC B H ] (3β). BuLi
2
9
10
3 2
2
9
10
(
0.13 mL of a 1.6 M solution in hexanes, 0.208 mmol) was added
dropwise to a cooled (0 °C) solution of [HNMe ]IX (0.050 g, 0.097
3
mmol) in THF (15 mL). Following warming to room temperature,
15
16
the dark yellow solution was frozen at −196 °C and [Rh(PPh ) Cl]
3
3
17
(
0.090 g, 0.097 mmol) was added and the reaction mixture allowed to
18
thaw to room temperature and stir overnight. Following filtration
through silica, solvents were removed in vacuo and the residue purified
by preparative TLC using a DCM/petrol eluent in a 1:1 ratio to afford
two major pale yellow bands.
0
α-[8-(8′-2′-Cp*-closo-2′,1′,8′-CoC B H )-2-H-2,2-(PPh ) -closo-
2
9
10
3 2
2
,1,8-RhC B H ] (3α). R 0.36. Yield 0.017 g, 0.016 mmol, 16%.
2 9 10 f
2
C H B CoP Rh requires: C 55.3, H 6.13. Found: C 55.8, H 6.08%.
5
0
66 18
2
1
H NMR δ 7.42−7.09 (m, 30H, C H ), 1.74 [s, 15H, C (CH ) ],
6
5
5
3 5
1
J
.65 (br s, 1H, C1′H), 1.40 (br s, 1H, C1H), −8.57 (ddd, 1H, RhH,
19
11 1
= 30.3 Hz, J = 24.2, 15.6 Hz). B{ H} NMR δ 0.9 to −8.5
RhH
PH
2
CH Cl , 2β·1.5CH Cl , and V application of the vertex-centroid
2 2 2 2
20
multiple overlapping resonances with maxima at 0.9, −6.0, −8.5 (total
integral 12B), −14.7 to −22.0 multiple overlapping resonances with
distance (VCD) and boron−hydrogen distance (BHD) methods
allowed cage C atoms bearing only H substituents to be clearly
distinguished from B atoms. Compounds 3α·2.5CH Cl and 3β·
3
1
1
maxima at −14.7, −15.5, −19.6, −22.0 (total integral 6B). P{ H}
NMR δ 37.35 (dd, 1P, J = 113.0 Hz, J = 22.8 Hz), 32.51 (dd, 1P,
2
2
RhP
PP
2
.5CH Cl have two crystallographically independent molecules
JRhP = 109.0 Hz, J = 22.8 Hz). ESIMS: envelope centered on m/z
2 2
PP
+
present in the asymmetric fraction of the unit cell, thus eight
metallacarborane cages in total. In these cages refinement of only
some of the cage H atoms was possible, and so the BHD method had
limited applicability. Nevertheless, in all eight cages C atoms were
identified unambiguously by the VCD approach. In all the
compounds studied the electron density corresponding to the Rh-
8
22 (M -PPh ).
3
β-[8-(8′-2′-Cp*-closo-2′,1′,8′-CoC B H )-2-H-2,2-(PPh ) -closo-
2
9
10
3 2
2
,1,8-RhC B H ] (3β). R 0.41. Yield: 0.019 g, 0.018 mmol, 18%.
2 9 10 f
C H B CoP Rh requires: C 55.3, H 6.13. Found: C 56.2, H 6.11%.
5
0
66 18
2
1
H NMR δ: 7.42−7.09 (m, 30H, C H ), 1.75 [s, 15H, C (CH ) ],
6
5
5
3 5
1
J
.66 (br s, 1H, C1′H), 1.38 (br s, 1H, C1H), −8.58 (ddd, 1H, RhH,
11 1
bound hydride ligand was located, but only in the case of 1·0.5CH Cl
= 28.9 Hz, J = 23.0, 14.2 Hz). B{ H} NMR δ: 0.8 to −8.4
2
2
RhH
PH
multiple overlapping resonances with maxima at 0.8, −6.7, −8.4 (total
integral 12B) and −14.9 to −21.9 multiple overlapping resonances
with maxima at −14.9, −15.5, −19.0, −21.9 (total integral 6B).
and V did positional refinement of the hydride lead to a chemically
sensible model. For 2α·2CH Cl , 2β·1.5CH Cl , 3α·2.5CH Cl , and
3β·2.5CH Cl , the hydride ligands were therefore restrained to Rh−H
= 1.58(2) Å and P···H = 2.55(2) Å, these distances being taken from
the successful hydride refinement in 1·0.5CH Cl . For 1·0.5CH Cl ,
α·2CH Cl , and 2β·1.5CH Cl , cage H atoms were allowed
positional refinement, while for 3α·2.5CH Cl and 3β·2.5CH Cl ,
they were set in idealized positions riding on their B or C atom with
2
2
2
2
2
2
2
2
31
1
P{ H} NMR δ: 37.18 (dd, 1P, J
= 113.0 Hz, J = 26.8 Hz),
RhP
PP
3
2.54 (dd, 1P, JRhP = 109.0 Hz, J = 26.8 Hz). ESIMS: envelope
2
2
2
2
PP
+
2
centered on m/z 822 (M −PPh ).
2 2 2 2
3
Further Spectroscopic Characterization of I and V. [3-H-3,3-
2
2
2
2
1
03
1
(
PPh ) -closo-3,1,2-RhC B H ] (I). Rh{ H} NMR δ: −972.93 (t,
3
2
2 9 10
JRhP = 125.7 Hz).
B−H = 1.12 Å and Ccage−H = 1.00 Å. All other H atoms were also
1
[
2-H-2,2-(PPh ) -closo-2,1,12-RhC B H ] (V). H NMR δ: 7.68−
treated as riding, with C
−H = 0.95 Å, C
phenyl
−H = 0.98 Å,
3
2
2
9
10
primary
6
.94 (m, 30H, C H ), 2.34 (br s, 1H, C12H), 1.49 (br s, 1H, C1H),
Ctertiary−H = 1.00 Å, and C −H = 1.00 Å. H atom displacement
parameters were constrained to 1.2 × U (bound B or C) except for
6
5
arene
1
1
1
−
8.79 (dt, 1H, RhH, JRhH = 27.4 Hz, JPH = 14.9 Hz). B{ H} NMR
eq
C
Inorg. Chem. XXXX, XXX, XXX−XXX