S
1
Supporting
I
nformation for the paper entitled,
A
S
uper
-
O
xidized
R
adical
C
ationic
I
cosahedral
B
oron
C
luster
Julia M. Stauber,
1
Josef Schwan,
2
Xinglong Zhang,
2
Jonathan C. Axtell,
1,3
Dahee Jung,
1
Brendon J. McNicholas,
2
Paul H. Oyala,
2
Andrew J. Martinolich
,
2
Jay R. Winkler,
2
Kimberly A. See,
2
Thomas F. Miller III,
2
*
Harry B. Gray,
2
*
Alexander M. Spokoyny
1
,
4
*
1
Department of Chemistry and Biochemistry, University of California, Los Angeles,
607 Charles
E. Young Dr E.,
Los Angeles, California, 90095, United States
2
Division of Chemis
try and Chemical Engineering
, California Institute of Technology,
1200 East
California Boulevard,
Pasadena, C
alifornia,
91125, Unite
d
States
3
The Dow Chemical Company
,
633 Washington St
.
,
Midland
,
Michigan
,
48674
, United States
4
California NanoSystems Institute, University of
Californ
ia, Los Angeles,
570 Westwood Plaza
,
Los Angeles, California, 90095, United States
*Correspondence to: spokoyny@chem.ucla.edu
(A.
M.
S.)
,
hbgray@caltech.edu (H. B. G.)
,
tfm@caltech.edu (T. F. M.)
S
2
Contents
S1.
General considerations
................................
................................
................................
.
3
S1.1.
Materials
................................
................................
................................
...................
3
S1.2.
Methods
................................
................................
................................
...................
3
S2.
Synthetic procedures and characterization data for all compounds
.........................
4
S2.1.
B
12
(O
-
3
-
methylbutyl)
12
(
1
)
................................
................................
.........................
4
S2.2.
[Na(Et
2
O)]
2
[B
12
(O
-
3
-
methylbutyl)
12
] ([Na(Et
2
O)]
2
[
1
])
................................
..................
8
S2.3.
[B
12
(O
-
3
-
methylbutyl)][SbCl
6
] ([
1
][S
bCl
6
])
................................
................................
.
10
S3.
Electrochemical measurements of 1
................................
................................
...........
12
S3.1.
Cyclic voltammetry of
1
................................
................................
...........................
12
S3.2.
Randles
-
Sevcik analysis of the [
1
]
0/
•
+
redox couple
................................
..................
13
S4.
X
-
ray photoelectron
spectroscopy data of [1][SbCl
6
], 1, and [Na(Et
2
O)]
2
[1]
.............
14
S5.
EPR data of [1][SbCl
6
]
................................
................................
................................
..
15
S6.
On
e
-
electron reduction of [1][SbCl
6
] to 1 with ferrocene
................................
...........
16
S7.
NMR stability study of [1][SbCl
6
]
................................
................................
.................
18
S8.
Attempted preparation of [1]
•
–
: treatment of 1 with hydrazine
................................
..
21
S9.
Computational details
................................
................................
................................
..
24
S9.1.
Me
thods
................................
................................
................................
..................
24
S9.2.
Geometry optimization and structural comparison of
1
and [
1
]
•
+
..............................
25
S9.3.
Calculated UV
-
vis spectra of
1
and [
1
]
•
+
................................
................................
...
26
S9.3.1.
1
................................
................................
................................
.......................
26
S9.3.2.
[
1
]
•
+
................................
................................
................................
...................
30
S9.4.
Electrostatic potential (ESP) of
1
and spin density plot of [
1
]
•
+
................................
.
38
S9.5.
[
1
]
0/
•
+
redox potential calculation
................................
................................
...............
39
S9.6.
11
B NMR chemical shift calculation of
1
................................
................................
...
39
S9.7.
Absolute energies from the optimized structures
................................
.....................
40
S9.8.
Coordinates of the optimized structures
................................
................................
..
41
S9.8.1.
1
................................
................................
................................
.......................
41
S9.8.2.
[
1
]
•
+
................................
................................
................................
...................
46
S10.
References
................................
................................
................................
....................
51
S
3
S1.
General considerations
S1.1.
Materials
All manipulations were performed under
an inert atmosphere of purified N
2
in a Vacuum
Atmospheres NexGen glovebox
unless otherwise indicated. All reagents were purchased from
Sigma Aldrich, Oakwood Chemicals, TCI, Fisher Scientific, or Alfa Aesar, and used as received
unless otherwise noted.
Dichloromethane
(DCM)
, tetrahydrofuran
(THF)
,
toluene,
and diethyl
ether
(Et
2
O)
were purified on a
JC Meyer
Glass Contour Solvent Purification System
and stored
under argon prior to use. A
ll other solvents were used as received
without further purification
unless otherwise specified (
acetone, acetonitrile (MeCN), ethyl acetate (Et
OAc), hexanes).
[TBA][PF
6
] was purchased from Sigma Aldrich and recrystallized three times from hot EtOH and
dried under
dynamic
vacuum at 80
°
C for 12 h prior to use.
[TBA]
2
[B
12
(OH)
12
]
was
prepared
following previously reported procedures
,
1
and
w
as
stored under an atmosphere of purified N
2
in
a Vacuum Atmospheres NexGen glovebox prior to use.
[N(2,4
-
Br
2
C
6
H
3
)
3
][SbCl
6
] was prepared
according to
a
repo
rted procedure,
2
and was stored under an inert atmosphere of N
2
at
-
30
°
C.
Deuterated solvents (C
6
D
6
,
CDCl
3
,
THF
-
d
8
) were obtained from Cambridge Isotope Laboratories
and degas
s
ed and stored over molecular sieves (4 Å beads) for at least
two
days prior to use
.
Celite
was
dried
by
heating
above
200
°
C
under
dynamic
vacuum
for at
least
24
h
prior
to
use
.
Molecular sieves
(4 Å beads
,
8
-
12 mesh
)
were activated by
heating
above
2
50
°
C
under
dynamic
vacuum
for at
least
24
h
prior
to
use
.
S1.2.
Methods
All NMR spectra were obtained on Bruker Avance 400 or 300 MHz broad band FT NMR
spectrometers.
1
H NMR and
13
C{
1
H
} NMR spectra were referenced to residual protio
-
solvent
signals, and
11
B{
1
H} chemical shifts were referenced to BF
3
•Et
2
O (15% in CDCl
3
, δ 0.0 ppm). ESI
-
MS data were collected on a Thermo Instruments Q
-
Exactive Plus Hybrid
Quadrupole
-
Orbitrap
instrument operating in ESI
-
positive
mode. Full mass
scan (
500
to
4000
m/z
) was used at 70,000
resolution, with automatic gain control (AGC) target of 1 x 10
6
ions, electrospray ionization
operating at a 1.5 kV spray voltage, and a capi
llary temperature of 250 °C
.
X
-
band continuous
wave
EPR measurements were carried out using
a Bruker EMX spectrometer
at
77K
with a
microwave frequency of
9.3468
GHz, and the data were
acquired
using
Bruker Win
-
EPR software
(ver. 3.0)
.
UV
-
vis measurements
were conducted using an Ocean Optics Flame
-
S
-
UV
-
VIS
-
ES
miniature spectrometer equipped with a DH
-
2000 UV
-
vis NIR light source. All measurements
were carried out using quartz cuvettes (1 cm path length) and conducted at 25 °C with solution
samples
at
the in
dicated
concentration
s
. Cyclic voltammetry measurements were performed with
a
Gamry
Instruments Interface 1010E potentiostat using a glassy carbon disc working electrode,
platinum wire counter electrode and a Ag
wire
pseudo
-
reference electrode.
Measurements were
conducted
with [TBA][PF
6
] (0.1 M, DCM) supporting electrolyte
in dry DCM
und
er an inert
atmosphere of
purified
N
2
and referenced
vs.
Fc/Fc
+
.
Microwave reactions were performed using a CEM
®
Discover SP microwave synthesis reactor.
All reactions were performed in
35
mL
Pyrex
microwave
pressure
vessels
purchased from CEM
with silic
one/PTFE caps. Teflon coated stir bars were used in the
vessels
with magnetic stirring
set to high with 15 s of premixing prior to temperature ramping. All microwave reactions were
carried out at 140 °C with the pressure release limit set to 250 psi and th
e maximum wattage set
to 250 W. The power applied was dynamically controlled by the microwave instrument and did
not exceed this limit for any reactions.