of 47
S
1
Supplementary Information for
Partial Synthetic Models of FeMoco with Sulfide and Carbyne Ligands:
Effect of Interstitial Atom in Nitrogen
a
se Active Site
Linh N. V. Le
1
, Gwendolyn A. Bailey
1
, Anna G. Scott
1
, Theodor Agapie
1
*
1
Division of Chemistry
and Chemical Engineering, California Institute of Technology, Pasadena, California
91125, United States
*To whom correspondence may be addressed.
Email:
agapie@caltech.edu
This PDF file includes:
Supplementary
text
Figures S1 to S
3
4
Tables S1 to S
4
SI References
Other supplementary materials for this manuscript include the following:
Combined Crystallographic Information File (CIF)
S
2
A)
Synthetic
detail
s
:
1.
General considerations
:
All reactions
were performed at room temperature in a N
2
-
filled MBraun glovebox or using standard
Schlenk techniques unless otherwise specified. Glassware was oven
-
dried at 140 °C for at least 2 h prior
to use and allowed to cool under vacuum.
BAC
(1, 2)
,
[NEt
4
][Tp*MoS
5
]
(3)
and KC
8
(4)
were prepared
according
to literature procedures, while
1
-
W
was prepared as reported
(5)
with minor modifications.
Diethyl ether, benzene, tetrahydrofuran (THF), acetonitrile (CH
3
CN), hexanes, and pentane were dried by
sparging
with N
2
for at least 15 min and then passing through a column of activated A2 alumina under
positive N
2
pressure, and stored over 3 Å molecular sieves prior to use. Dimethylformamide (DMF) was
purchased in anhydrous form from MilliporeSigma
®
, cannula
-
trans
ferred to an oven
-
dried Schlenk tube,
degassed via several consecutive cycles of active vacuum and agitation on the Schlenk line, brought into
the glove box and stored over 3 Å molecular sieves prior to use.
1
H spectra were recorded on a Varian
300 MHz or
400 MHz spectrometer.
13
C NMR spectra were recorded on a Varian 400 MHz spectrometer.
Deuterated acetonitrile (CD
3
CN) and deuterated benzene (C
6
D
6
) were purchased from Cambridge
Isotope Laboratories, dried over calcium hydride (for CD
3
CN) or sodium/benzoph
enone ketyl (for C
6
D
6
),
degassed by three freeze
pump
thaw cycles, and vacuum
-
transferred prior to use.
2.
Procedures:
Synthesis of
1
-
W
. In a glovebox,
[NEt
4
][Tp*WS
3
]
(prepared as reported
(6)
, with an additio
nal round of
precipitation of the crude material from DMF/Et
2
O before recrystallization in MeCN/Et
2
O
)
(1.500 g,
2
.
12
mmol, 1 eq),
FeCl
2
(0.
807
g,
6
.
36
mmol, 3 eq) and
NEt
4
Cl
(0.
351
g, 2.
12
mmol,
1 eq) were dissolved in
90 mL DMF. To this solution, sodium benzophenone ketyl monoanion (63.63 mL, 0.1 M in THF, 6.36
mmol, 3 eq
) (freshly prepared by stirring 1 eq Na
0
in a THF solution of 1 eq benzophenone for several
hours until all the Na
0
is consumed) was added slowly with stirring. The reaction mixture was stirred at
room temperature for 18 h, after which the crude product wa
s collected as a dark purple precipitate on a
frit and washed with THF. This solid was purified by dissolving in ~200 mL
MeCN, filtering
and removing
the solvent
in vacuo
.
Additional material could be collected by vapor diffusion of Et
2
O into the mother
li
quor from the first filtration.
Total yield: 1.98 g (81%). NMR data for
1
-
W
prepared by this method are
identical to previous reports
(5)
.
Synthesis of
[NEt
4
][Tp*MoS
3
]
. To a solution of
[NEt
4
][Tp*MoS
5
]
(10.0 g, 14.6 mmol, 1 eq) in acetonitrile
(400 mL) was added solid triphenylphosphine (8.62 g, 32.9 mmol, 2.25 eq
). The reaction was stirred for
30 min, and then concentrated to 50 mL and then precipitated with diethyl ether (300
-
400 mL) and
filtered. Repeating this protocol twice, followed by washing with diethyl ether (250 mL) afforded
[NEt
4
][Tp*MoS
3
]
as a brown
-
gr
een solid (7.1 g, 78%).
1
H NMR (400 MHz, CD
3
CN):
δ
5.78 (s, 3H,
pyrazole
-
H
), 3.14 (q,
3
J
HH
= Hz, 8H, NC
H
2
), 3.09 (s, 9H, pyrazole
-
C
H
3
), 2.35 (s, 9H, pyrazole
-
C
H
3
), 1.19
(m, 12H, NCH
2
C
H
3
) ppm.
13
C{
1
H} NMR (101 MHz, CD
3
CN):
δ
153.00 (s, pyrazole
-
C), 143.18 (s, pyrazole
-
C), 107.41 (s, pyrazole
-
C
H), 53.05 (s, N
C
H
2
), 16.77 (s, pyrazole
-
C
H
3
), 12.89 (s, pyrazole
-
C
H
3
), 7.64 (s,
NCH
2
C
H
3
) ppm
. Elemental analysis data for samples of
[NEt
4
][Tp*MoS
3
]
prepared in this fashion
reproducibly shows the anticipated content for H and N, but low content for C,
even following subsequent
recrystallizations, possibly due to incomplete carbon combustion
(7)
.
Representative data are as follows.
Anal.
calcd
(%) for C
23
H
42
BMoN
7
S
3
(M
r
= 619.58): C, 44.59; H, 6.83; N, 15.83. Found: C, 43.50; H, 6.65;
N, 15.39.
Synthesis of
1
-
Mo
. In the glovebox, a solution of
[NEt
4
][Tp*MoS
3
]
(1.00 g, 1.61 mmol, 1 eq), FeCl
2
(0.614
g, 4.84 mmol, 3 eq), and NEt
4
Cl (0.268 g, 1.61 mmol, 1 eq) was prepared
in DMF (6.0 mL). Separately, a
solution of benzophenone (0.882 g, 4.84 mmol, 3 eq) in THF (50 mL) was reduced over Na
0
(0.111 g,
4.84 mmol, 3 eq) by vigorous stirring over 3 h with a magnetic stir bar. The resulting blue solution of
benzophenone ketyl radi
cal was added dropwise to the brown reaction solution. After 16 h, the resulting
suspension was filtered, and the blue filter cake was washed with THF (25 mL). This solid was
recrystallized by vapor diffusion of diethyl ether into acetonitrile to yield
9
a
s an analytically pure, blue
crystalline solid (1.37 g, 80%).
1
H NMR (400 MHz, CD
3
CN):
δ
3.10 (
br
s), 1.40 (
br
s),
-
21.87 (
br
s)
ppm.
Anal. calcd (%) for C
31
H
62
BCl
4
Fe
3
MoN
8
S
3
(M
r
= 1059.17): C, 35.15; H, 5.90; N, 10.58. Found: C, 34.96; H,
S
3
5.81; N, 10.29. X
-
ray quality needles were grown via repeated crystallizations by vapor diffusion,
identically as above.
Synthesis of
2
-
W
. In a glovebox,
1
-
W
(0.867 g, 0.76 mmol, 1 eq),
BAC
(0.536 g, 2.27 mmol, 3 eq) and
NaBPh
4
(0.776 g, 2.27 mmol, 3 eq)
were placed in a flask with a stir bar. To this mixture was added 35
mL THF with stirring. The solids dissolved to form a dark red solution, along with the formation of a white
precipitate. After 16 h, the mixture was filtered through Celite inside the bo
x and the filtrate was
evaporated to give a dark red solid. The solid was washed in C
6
H
6
to remove a dark brown impurity and
recrystallized by vapor diffusion with THF/pentane to yield X
-
ray quality brown needles. Yield: 1.22 g
(89%).
1
H NMR (300 MHz, CD
3
CN) δ 18.16, 7.39, 7.25, 6.98, 6.85, 1.30, 1.18, 1.13,
-
0.15,
-
10.03. Anal.
calcd (%) for C
84
H
126
N
12
B
2
ClWS
3
Fe
3
(M
r
= 1808.61): C, 55.78; H, 7.02; N, 9.29. Found: C, 55.65; H, 7.12;
N, 9.13.
Synthesis of
2
-
Mo
. In a glovebox,
1
-
Mo
(0.375 g, 0.354 mmol, 1 eq
) and
BAC
(0.251 g, 1.06 mmol, 3 eq)
were combined in THF, forming a blue suspension. Then, NaBPh
4
(0.364 g, 1.06 mmol, 3 eq) was added
dropwise as a solution in THF. A darkening of the reaction color to black was observed, concomitant with
formation of a
white precipitate. After 16 h, the mixture was filtered through Celite, and the filtrate was
evaporated to yield a black solid. This solid was washed with diethyl ether (3 × 5 mL) and C
6
H
6
(2 × 1 mL)
to remove a brown impurity. The solid was then recrystal
lized by vapor diffusion of diethyl ether into THF
to yield
10
as a black crystalline solid (0.450 g, 74%). On a 40 mg scale, the crystal quality was sufficient
for structural identification by XRD.
1
H NMR (400 MHz, CD
3
CN)
δ
7.25 (s), 6.97 (s), 6.84 (s),
0.32 (
br
s),
-
10.89 (
br
s). Analytically pure samples of
2
-
Mo
were prepared via a second recrystallization by identical
means. Anal.
calcd
(%) for C
84
H
126
B
2
ClFe
3
MoN
12
S
3
(M
r
= 1720.75): C, 58.63; H, 7.38; N, 9.77. Found: C,
58.50; H, 7.27; N, 9.57.
Synthesis of
3
. In a glovebox,
2
-
W
(
364
.0 mg, 0.
201 mmol, 1 eq) was dissolved in 30 mL THF, making
sure that all the solid goes into solution. Potassium naphthalenide (2.214 mL
,
0.1 M in THF, 0.221 mmol,
1.1 eq) was added to the reaction dropwise while sti
rring using a syringe at room temperature.
After 1 h,
the reaction mixture was filtered through Celite and evaporated to dryness. The dark brown residue was
washed with Et
2
O and the crude product was
recrystallized by vapor diffusion of pentane
into a
conc
entrated THF solution
to give X
-
ray quality dark hexagons. Yield:
274.0 mg (77
%).
1
H NMR (300
MHz, CD
3
CN) δ 41.79, 10.81, 8.44, 7.30, 7.02, 6.87,
-
0.08,
-
23.02.
Anal. calcd (%) for
C
84
H
126
N
12
B
2
WS
3
Fe
3
(M
r
= 1773.18): C, 56.90; H, 7.16; N, 9.48. Found: C, 57.
3
0; H, 7.32; N, 8.99
.
Synthesis of
4
-
W
.
From
2
-
W
: In a glovebox,
2
-
W
(1.53 g, 0.85 mmol, 1 eq) and excess KC
8
(0.400 g, 2.96
mmol, 3.5 eq
) were placed in a flask with a stir bar along with 35 mL THF. The dark brown solution was
stirred at room temperature for 24 h or until no more
2
is seen by NMR spectroscopy. The mixture was
then filtered through Celite inside the box and the filtrate was
evaporated to give a dark brown solid. The
product was extracted into Et
2
O, filtered and the solvent removed to yield a dark brown solid. Yield: 1.08 g
(88%).
From
3
: In a glovebox,
3
(0.376 g, 0.21 mmol, 1 eq) and
excess
KC
8
(0.043 g, 3.18 mmol, 1.5 eq)
were
placed in a flask with a stir bar along with 20 mL THF. The dark brown solution was stirred at room
temperature for 24 h or until no more
3
is seen by NMR spectroscopy. The mixture was then filtered
through Celite inside the box and the filtrate was
evaporated to give a dark brown solid. The product was
extracted into Et
2
O, filtered and the solvent removed to yield a dark brown solid. Yield: 0.259 g (84%).
X
-
ray quality crystals of
4
-
W
were grown by
placing
a concentrated pentane
solution at
-
35
°
C for several
days
. Pure crystalline material for cyclic voltammetry can also be prepared by vapor diffusion of pentane
into a concentrated solution of
4
-
W
in Et
2
O
at
-
35°C
over
several days.
1
H NMR (300 MHz, C
6
D
6
)
δ
19.24,
10.20, 9.12, 5.15, 5.06, 3.94, 3.27, 2.78, 2.44, 1.24,
-
1.60,
-
4.84,
-
7.23,
-
11.00.
Elemental analysis data
for samples of
4
-
W
prepared in this fashion reproducibly shows the anticipated content for H and N, but
low content for C, even following sub
sequent recrystallizations. This could be due to incomplete carbon
combustion, a known problem for the analysis of metal complexes by combustion analysis
(7)
.
Representative data are as follows.
Anal. calcd (%) for C
60
H
106
N
12
BWS
3
Fe
3
(M
r
= 1453.95): C, 49.56; H,
7.35; N, 11.56. Found: C, 48.50; H, 7.18; N, 11.34.
S
4
Synthesis of
4
-
Mo
. In a glovebox, KC
8
(0.046 g, 0.34 mmol, 3.5 eq) was added to a solution of
2
-
Mo
(0.167 g, 0.097 mmol, 1 eq
) in THF (5 mL) with stirring. A color change to brown was immediately
apparent. After stirring overnight (16 h), the reaction was filtered through Celite and the filtrate was
concentrated to dryness
in vacuo
. Extraction into diethyl ether, filtration, and
removal of the solvent from
the filtrate provided
4
-
Mo
as a brown solid (0.130 g, 99%)
.
X
-
ray quality crystals of
4
-
Mo
were grown by
vapor diffusion of pentane into
a con
centrated THF solution at room temperature over several days
.
1
H
NMR (400 MHz, C
6
D
6
)
δ
16.14, 11.70, 8.30, 5.88, 5.46, 4.14, 1.73, 1.12, 0.42,
-
2.55,
-
4.74,
-
5.87,
-
13.31
ppm. Elemental analysis data for samples of
4
-
Mo
prepared in this fashion reproducibly shows the
anticipated content for H and N, but low content for C, possibly due to i
ncomplete carbon combustion
(7)
.
Representative data are as follows. Anal.
calcd
(%) for C
60
H
106
B
F
e
3
MoN
12
S
3
(M
r
= 1366.07): C, 52.75; H,
7.82; N, 12.30. Found: C, 51.80; H, 7.73; N, 12.38.
Synthesis of
5
. In a glovebox,
4
-
W
(prepared from
3
)
(0.0200 g, 0.14 mmol, 1 eq) was dissolved in
2 mL
C
6
H
6
. To this solution, MeOTf (0.138 mL, 0.1 M solution in toluene, 0.14 mmol, 1 eq) was added dropwise
with stirring using a syringe. A dark brown precipitate appeared immediately. The reaction was stirred for
3 h, after which the mother liquor beca
me very light brown and the
crude
5
precipitate was collected by
filtration.
This solid was the further purified by vapor diffusion of pentane into a concentrated solution in
THF to deposit a dark microcrystalline powder.
Yield:
0
.0
205 g (92
%).
When conduc
ted on larger scales,
the product becomes less pure even after crystallization and the yield drops to 50
60%.
Despite the
scale, however, samples of
5
still contain small amounts of unidentified impurities, which are observed in
the cyclic voltammogram.
X
-
ray quality crystals can be grown by slow evaporation of a concentrated
MeCN solution of
5
at room temperature.
1
H NMR (300 MHz, CD
3
CN) δ 15.64, 14.28, 10.87, 8.64, 8.32,
7.01, 6.45, 6.31, 5.57, 5.17, 3.55, 1.39, 0.99,
-
0.03,
-
0.18,
-
2.58,
-
5.38,
-
90.01.
Anal. calcd (%) for
C
62
H
109
N
12
O
3
F
3
BWS
4
Fe
3
(M
r
= 1618.05): C, 46.02; H, 6.79; N, 10.39. Found: C, 43.60; H, 6.95; N, 9.78.
Synthesis of
6
. In a glovebox,
3
(40.0 mg, 0.023 mmol, 1 eq) and N
B
u
4
N
3
(6.4 mg, 0.023 mmol, 1 eq
)
were dissolved in 2 mL THF in a vial with a stir bar. The dark brown solution was stirred at room
temperature for 3 h, after which the solvent was removed
in vacuo
. The product was extracted into Et
2
O,
which was left to evaporate at room temperature over
the course of the day to yield dark X
-
ray quality
crystal.
When almost all the solvent has evaporated, the remaining supernatant was discarded and the
crystals were washed with pentane.
Yield: 18.2 mg (55%). Samples of
6
typically contain small amounts
of
impurities including
4
-
W
, which could not be removed due to similar solubilities.
1
H NMR (300 MHz,
C
6
D
6
) δ
5.82, 2.03, 1.54, 1.13.
Anal. calcd (%) for C
60
H
106
N
13
BWS
3
Fe
3
(M
r
= 1467.96): C, 49.09; H, 7.28;
N, 12.40. Found: C, 48.91; H, 7.57; N, 11.41.
Synthesis of
7
. In a glovebox,
3
(89.3 mg, 0.050 mmol, 1 eq)
was dissolved in 5 mL TH
F. To this solution
was added
Me
3
SiN
3
(
0.504 mL
,
0.1 M in THF, 0.050
mmol, 1 eq)
using a syringe
. The dark brown
solution was stirred at room temperature for
2
h, after which the solvent was removed
in vacuo
. The
product was
washed with
Et
2
O,
then recrystallized by vapor diffusion of Et
2
O into a concentrated THF
solution to yield X
-
ray quality dark diamonds
. Yield:
76.1
mg (
81
%).
1
H NMR (300 MHz, CD
3
CN) δ
10.39,
7.27, 6.98, 6.85, 5.83, 0.52,
-
1.39.
Anal. calcd (%) for C
87
H
135
N
13
B
2
SiWS
3
Fe
3
(M
r
= 1860.37): C, 56.17; H,
7
.
31; N, 9.79. Found: C, 56
.
12; H, 7.33; N, 9.85
.
Synthesis of
8
.
In a glovebox,
3
(150 mg, 0.085 mmol, 1 eq) was dissolved in 10 mL THF. To this
solution
was added SPPh
3
(25 mg, 0.085 mmol, 1 eq) in portions. The dark brown solution was stirred at room
temperature for 6 h, after which the reaction mixture was filtered and the solvent was then removed
in
vacuo
. The product was washed with Et
2
O, then
recrystallized by vapor diffusion of Et
2
O into a
concentrated THF solution to yield X
-
ray quality dark rods. Yield: 84.0 mg (55%).
1
H NMR (300 MHz,
CD
3
CN) δ 14.35, 7.07, 6.79, 6.64, 5.23, 2.01, 1.90, 1.85,
1.58,
-
1.94
. Anal. calcd (%) for
C
84
H
126
N
12
B
2
WS
4
F
e
3
(M
r
= 1805.25
): C, 55.89; H, 7.04; N, 9.31. Found: C, 55.82; H, 6.86; N, 10.17
.
S
5
3.
NMR spectra
:
Figure S
1
:
1
H NMR spectrum (400 MHz, CD
3
CN) of
[NEt
4
][
Tp*MoS
3
]
. Solvent peak is
indicated by
asterisk (*).
S
6
Figure S
2
:
13
C{
1
H} NMR spectrum (101 MHz, CD
3
CN) of
[NEt
4
][Tp*MoS
3
]
. Solvent peaks are indicated
by asterisks (*).
S
7
Figure S
3
:
1
H NMR spectrum (400 MHz, CD
3
CN) of
1
-
Mo
. Solvent peak
is
indicated by asterisk (*).
S
8
Figure S
4
:
1
H NMR (300 MHz, CD
3
CN) spectrum of
2
-
W
. Solvent peaks are indicated by asterisks (*).
*
*
S
9
Figure S
5
:
1
H NMR
spectrum (400 MHz, CD
3
CN) of
2
-
Mo
. Solvent peaks are indicated by asterisks (*).
S
10
Figure S
6
:
1
H NMR
(300 MHz, CD
3
CN)
spectrum of
3
. Solvent peaks are indicated by asterisks (*).
*
*
S
11
Figure S
7
:
1
H NMR
(300 MHz, C
6
D
6
)
spectrum of
4
-
W
. Solvent peak
is
indicated by asterisk (*).
*
S
12
Figure S
8
:
1
H NMR spectrum (400 MHz, C
6
D
6
)
of
4
-
Mo
. Solvent peak is
indicated by asterisk (*).
S
13
Figure S
9
:
1
H NMR
(300 MHz, CD
3
CN)
spectrum of
5
. Solvent peak
is
indicated by asterisk (*).
*
S
14
Figure S
10
:
1
H NMR
(300 MHz, C
6
D
6
)
spectrum of
6
. Solvent peak is indicated by asterisk
(*).
*
S
15
Figure S
11
:
1
H NMR
(300 MHz, CD
3
CN)
spectrum of
7
. Solvent peaks
are indicated by asterisks (*).
*
*
*
S
16
Figure S
12:
1
H NMR (400 MHz, C
D
3
CN) spectrum of
8
. Solvent peaks are indicated by asterisks (*).
*
S
17
B)
Electrochemical information
:
1.
Electrochemical measurements
:
Cyclic voltammetry
experiments
w
ere
performed with a Pine Instrument Company AFCBP1
biopotentiostat with the
AfterMath
software package. All measurements were performed in a three
-
electrode cell, which consisted of glassy carbon (working;
= 3.0 mm), Ag wire (
reference
),
and bare Pt
wire (
counter
), in a N
2
-
filled M
Braun glovebox at room temperature. Dry CH
3
CN that contained
0.2 M
[Bu
4
N][PF
6
] was used as the electrolyte solution.
Redox potentials are reported relative to
the
ferrocene/ferrocenium
redox wave
(Fc/Fc
+
;
ferroc
ene added as an internal standard
).
The open circuit
potential was measured prior to each voltammogram being collected. Voltammograms were scanned
reductively in order to minimize the oxidative damage that was frequently observed on scanning more
oxidative
ly.
2.
Additional electrochemical plots
:
S
18
Figure
S
13
: CV of
4
-
W
at different scan rates
, showing the two most negative
redox events
S
19
Figure
S
14
: Peak current vs. square root of scan rate for the
two most negative
redox features in
4
-
W
S
20
Figure S
15
: CV of
4
-
W
at different scan rates for the
most positive redox event
S
21
Figure
S
16
: Peak current vs. square root of scan rate for the most positive redox feature in
4
-
W
S
22
Figure
S
17
: CV of
4
-
W
including all 3 redox events
at 200 mV s
-
1
.
Note the appearance of decomposition
products
marked by asterisks (*), compared to CVs with only the two most negative redox events
.
*
*
S
23
Figure
S
18
: CV of
4
-
Mo
at different scan rates, showing the two most negative
redox events
S
24
Figure
S
19
: Peak current vs. square root of scan rate for the two most negative redox features in
4
-
Mo
S
25
Figure
S
20
: CV of
4
-
Mo
at different scan
rates for the most positive redox event
S
26
Figure
S
21
: Peak current vs. square root of scan rate for the most positive redox feature in
4
-
Mo
S
27
Figure
S
22
: CV of
5
at different scan rates
S
28
Figure
S
23
: Peak current vs. square root of scan rate for the redox features in
5
S
29
Figure
S
24
: CV of
6
at different scan rates
S
30
Figure
S
25
: Peak current vs. square root of scan rate for the redox features in
6
S
31
Figure
S
26
: CV of
7
at different scan rates
S
32
Figure
S
27
: Peak current vs. square root of scan rate for the redox features in
7
S
33
Figure
S
28
: CV of
8
at different scan rates
S
34
Figure
S
29
: Peak current vs. square root of scan rate for the redox features in
8
S
35
C)
Crystallographic information
:
1.
X
-
ray crystallography
:
XRD data were collected at 100 K on a Bruker AXS D8 KAPPA or Bruker AXS D8 VENTURE
diffractometer [microfocus sealed X
-
ray tube, λ(Mo Kα) = 0.71073 Å or λ(Cu Kα) = 1.54178 Å]. All
manipulations, including data collection, integration, and scaling, were car
ried out using the Bruker
APEX3
software
(8)
.
Absorption corrections were applied using
SADABS
(9)
.
Structures were solved by
direct methods using
XS
(incorporated into
SHELXTL
)
(10)
,
Sir92
(11)
or
SUPERFLIP
(12)
and refined
using full
-
matrix least
-
squares on
CRYSTALS
(13)
or
Olex2
(14)
to convergence. All non
-
H atoms were
refined using anisotropic displacement parameters. H atoms were placed in idealized positions and
refined using a riding model. Because of the size of the compounds most crystals included solvent
-
accessible
voids that contained a disordered solvent. The solvent could be either modeled satisfactorily,
or accounted for using
either
the
SQUEEZE
procedure in the
PLATON
software package
(15)
,
or a
solv
ent mask in
Olex2
(14)
.
2.
Additional information:
Special refinement details for
1
-
Mo
. The asymmetric unit
contain
s
3 co
-
crystallized acetonitrile molecules,
whose disorder across the infinite rotation axis could not be modelled satisfactorily. Therefore, a solvent
mask was calculated in
Olex2
(14)
whereby 60 electrons were found in a volume of 67 Å
3
, consistent with
the presence of 3[C
2
H
3
N] per asymmetric un
it.
Special refinement details for
2
-
W
. The asymmetric unit of the structure contains 5 co
-
crystallized THF
solvent molecules. Bond lengths restraints and similarity restraints for anisotropic displacement
parameters (ADPs) were applied to one THF molecule to obtain a stable model. When refine
d freely,
atom C31 on one
i
Pr moiety becomes unstable and physically unreasonable in terms of ADPs, so
similarity restraints were applied for the ADPs of atoms C30
C32 on that
i
Pr group.
Special refinement details for
2
-
Mo
. The asymmetric unit
of the st
ructure
contain
s
diffuse solvent peaks,
which could not be modelled satisfactorily.
Therefore, the electron density for co
-
crystallized solvent
molecules were accounted for using the
SQUEEZE
procedure in
PLATON
(15)
, whereby
1
000
electrons
were found in a volume of
4699
Å
3
, consistent with the presence of
3
[C
4
H
10
O] in the asymmetric unit.
Special refinement details for
3
. The asymmetric unit of the structure contains one co
-
crystallized THF
solvent molecule, which is
disordered over 2 positions with occupancies of 60% and 40%. The BPh
4
counteranion is also disordered over 2 positions, with occupancies of 45% and 55%.
Special refinement details for
4
-
W
. The asymmetric unit of the structure contains diffuse solvent peaks,
which could not be modeled satisfactorily. Therefore, the electron density for co
-
crystallized solvent
molecules were accounted for using the
SQUEEZE
procedure in
PLATON
(15)
, whereby
2312
electrons
were found in a volume of
14
735
Å
3
, consistent with the presence of
3
[C
5
H
12
] in the asymmetric unit.
Special refinement details for
4
-
Mo
.
The asymmetric unit of the structure contains
2
co
-
crystallized THF
solvent
molecules.
One THF
molecule is disordered over 2 positions
,
with occupancies of 69% and 31%.
One BAC ligand is also disordered over 2 positions, with occupancies of 64% and 36%.
Special refinement details for
6
. The asymmetric unit of the structure contains
one co
-
crystalli
zed Et
2
O
solvent molecule, which could be modeled
with
geometric and ADP restraints. T
he remaining solvent
molecules are heavily disordered and
could not be modeled satisfactorily. Therefore, the electron density
for co
-
crystallized solvent molecules were accounted for using the
SQUEEZE
procedure in
PLATON
(15)
,
whereby
50
electrons were found in a volume of
540
Å
3
, c
onsistent with the presence of
0.5
[C
4
H
10
O] in
the asymmetric unit.
S
36
Special refinement details for
7
. The asymmetric unit of the structure contains 3 co
-
crystallized THF and 1
Et
2
O solvent molecules. Bond lengths restraints and similarity restraints
for
ADPs were applied to the
Et
2
O
molecule to obtain a stable model.
Special refinement details for
8
. The asymmetric unit of the structure contains
highly disordered solvent
molecules, which could not be modeled satisfactorily. Therefore, the electron density for co
-
crystallized
solvent
molecules were accounted for using the
SQUEEZE
procedure in
PLATON
(15)
, whereby
662
electrons were found in a volume of
2495
Å
3
, consistent with the presence of
4
[C
4
H
10
O] in the asymmetric
unit.
One
N
i
Pr
2
group
is
disordered
over 2 positions, with occupancy
of 50% each.