European Journal of Inorganic Chemistry
10.1002/ejic.201700361
COMMUNICATION
Conclusions
equipped with an Astec CHIRALDEX G-TA column and a FID detector.
[
21]
Quantification was achieved from calibration curves.
The catalytic activity of manganese and cobalt compounds
containing all the carboranylcarboxylate ligand, 1-CH
3
-2-CO
2
-
Catalytic water oxidation: the water oxidation measurements were
carried out by GC-MS. To a flask containing 112 mg (0.204 mmols) of
Ce(NH ) (NO ) under stirring and inert atmosphere, were added 2 mL of
1
,2-closo-C 10 LH, have been tested in the epoxidation of
2 10
B H
aliphatic and aromatic alkenes using peracetic acid as oxidant.
Manganese complexes have proven to be active in the
epoxidation of alkenes after 4 minutes of reaction, showing total
conversion and high selectivity values, in most of the cases,
whereas the cobalt complex displays less activity. The catalytic
results highlight the role of the carboranylcarboxylate ligand in
the selectivity of the processes, where the carborane cluster
seems to have a distinctive electronic and/or structural influence
in the stabilization of the intermediate species formed with
respect to acetate. It is found that the coordination of the
carboranylcarboxylate ligand LH to the metal ion is crucial in the
performance of the compounds as catalysts.
4
2
3 6
IV
an aqueous solution of CF SO H (pH 1.0). Once the Ce was dissolved,
3
3
0.51 mL of a solution 2mM of catalyst 1 in water was injected to the
above solution under stirring and under nitrogen atmosphere.
Immediately, measurements of the evolution of O vs time were recorded.
2
Acknowledgements
This research has been financed by the Spanish Ministerio de
Economía
y Competitividad (CTQ2015-66143-P; CTQ2016-
75150-R) and Generalitat de Catalunya through project 2014-
SGR-149. MF thanks Generalitat de Catalunya for
predoctoral grant. CV thanks COST CM 1302 project.
a FI
Experimental Section.
Keywords: carboranes • manganese • cobalt • oxidation •
Materials and preparations: all reagents used in the present work were
obtained from Aldrich Chemical Co and were used without further
purification. Reagent grade organic solvents were obtained from SDS
and high purity de-ionized water was obtained by passing distilled water
carboxylate
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through a nano-pure Mili-Q water purification system. 1-CH
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-1,2-closo-
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C B H11 was purchased from Katchem. 1-CH -2-CO H-1,2-closo-
[
24]
[16a]
16b]
[17]
C B H
2 10 10
carboranylcarboxylate complexes tested 1
2-4
6
[
[
3]
and [Mn
3
(OAc)
6
(2,2’-bpy)
2
]
complex were prepared according to
1
literature procedures. All the oxidation manipulations were performed
under inert atmosphere.
[
6
Instrumentation and Measurements: GC measurements were taken in
a Shimadzu GC-2010 gas chromatography apparatus equipped with an
Astec CHIRALDEX G-TA column and a FID detector. FT-IR spectra were
taken in a Mattson-Galaxy Satellite FT-IR spectrophotometer containing
a MKII Golden Gate Single Reflection ATR System. NMR spectra were
recorded with a Bruker ARX 300 or a DPX 400 instrument equipped with
rd
[
5
[
2
1
1
11
the appropriate decoupling accessories.
H
and H{ B} NMR
[
13
1
11
(
300.13/400.13 MHz), C{ H} NMR (75.47/100.62 MHz) and B and
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11
1
B{ H} NMR (96.29/128.37 MHz) spectra were recorded in d
6
-acetone,
1
1
CD
referenced to external BF
3 4
NMR spectra were referenced to Si(CH )
2
Cl
2
and D O . Chemical shift values for B NMR spectra were
2
1
1
11
13
1
3
OEt
2
and those for H, H{ B} and C{ H}
. Chemical shifts are reported
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2 2
Catalytic epoxidation: a CH Cl (2.5 mL) solution of alkene (260 μmol),
catalyst (2.6 μmol) and biphenyl (250 μmol, internal standard) was
prepared in a 5 mL flask and cooled in an ice bath. Afterwards, 32 %
peracetic acid (520 μmol) was slowly added via syringe under stirring at
0
ºC. The reaction vessel was then taken out of the ice bath and allowed
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to progressively warm to room temperature. Each aliquot of the reaction
taken for analysis was filtered through a basic alumina plug and was
4
Mola, E. Mas-Marza, X. Sala, I. Romero, M. Rodriguez, C. Viñas, T. Parella,
analysed in
a Shimadzu GC-2010 gas chromatography apparatus
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