Subphthalocyanine encapsulated within MIL-101(Cr)-NH2 as a solar light photoredox catalyst for dehalogenation of α-haloacetophenones

Article abstract of DOI:10.1039/c9dt04004h

Subphthalocyanine has been incorporated into a robust metal-organic framework having amino groups as binding sites. The resulting SubPc?MIL-101(Cr)-NH₂ composite has a loading of 2 wt%. Adsorption of subphthalocyanine does not deteriorate host crystallinity, but decreases the surface area and porosity of MIL-101(Cr)-NH₂. The resulting SubPc?MIL-101(Cr)-NH₂ composite exhibits a 575 nm absorption band responsible for the observed photoredox catalytic activity under simulated sunlight irradiation for hydrogenative dehalogenation of α-haloacetophenones and for the coupling of α-bromoacetophenone and styrene. The material undergoes a slight deactivation upon reuse. In comparison to the case of phthalocyanines the present study is one of the few cases showing the use of subphthalocyanine as a photoredox catalyst, with its activity derived from site isolation within the MOF cavities.

Full text of DOI:10.1039/c9dt04004h

Showcasing research from Professor Garcia's laboratory,
Institute of Chemical Technology, Technical University of
Valencia, Spain.
As featured in:
Volume 48 Number 48 28 December 2019 Pages 17693–17954
Dalton
Subphthalocyanine encapsulated within MIL-101(Cr)-NH2
as a solar light photoredox catalyst for dehalogenation of
-haloacetophenones
Transactions
An international journal of inorganic chemistry
rsc.li/dalton
The figure illustrates a molecule of subphathlocyanine attached
to the MIL-101 structure and how light can activate it to promote
dehalogenation and coupling.
ISSN 1477-9226
PAPER
Masaki Matsuda et al.
Intermolecular interactions of tetrabenzoporphyrin- and
phthalocyanine-based charge-transfer complexes
See Hermenegildo García et al.,
Dalton Trans., 2019, 48, 17735.
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Subphthalocyanine encapsulated within
MIL-101(Cr)-NH2 as a solar light
photoredox catalyst for dehalogenation
of α-haloacetophenones†
Cite this: Dalton Trans., 2019, 48,
17735
Andrea Santiago-Portillo,a Sonia Remiro-Buenamañana,b Sergio Navalóna and
a,b,c
Hermenegildo García
*
Subphthalocyanine has been incorporated into a robust metal–organic framework having amino groups
as binding sites. The resulting SubPc@MIL-101(Cr)-NH2 composite has a loading of 2 wt%. Adsorption of
subphthalocyanine does not deteriorate host crystallinity, but decreases the surface area and porosity of
MIL-101(Cr)-NH2. The resulting SubPc@MIL-101(Cr)-NH2 composite exhibits a 575 nm absorption band
responsible for the observed photoredox catalytic activity under simulated sunlight irradiation for hydro-
genative dehalogenation of α-haloacetophenones and for the coupling of α-bromoacetophenone and
styrene. The material undergoes a slight deactivation upon reuse. In comparison to the case of phthalo-
cyanines the present study is one of the few cases showing the use of subphthalocyanine as a photoredox
catalyst, with its activity derived from site isolation within the MOF cavities.
Received 11th October 2019,
Accepted 11th November 2019
DOI: 10.1039/c9dt04004h
rsc.li/dalton
well-established as photocatalysts,10 the use of subphthalo-
cyanines has so far not been reported in spite of the intense
Introduction
Metal–organic frameworks (MOFs) are currently among the absorption band that these macrocyclic dyes exhibit in the
most intensely studied photocatalysts due to the efficient visible region.11–13
photoinduced electron transfer from the excited linker to the
In the present study, the preparation of MIL-101(Cr)-NH2
metal nodes.1–9 However, very frequently organic linkers do containing subphthalocyanine (SubPc@MIL-101(Cr)-NH2) as a
not show photoresponse under visible light irradiation and visible light harvester unit has been described. This composite
different strategies have been developed to expand MOF photo- exhibits activity for the sunlight photoredox catalytic hydroge-
response to the visible region. Among them, the strategy that native debromination of bromoacetophenone in the presence
has been widely used is the substitution of an aromatic linker of electron donors (photoredox reaction).14
with amino groups that introduce a new n → π* electronic
transition with an onset at about 450 nm.2 However, in most
of the cases, amino group substitution does not expand the
photoresponse towards the red beyond 450 nm. For this
reason, alternative strategies consisting of the anchoring of the
Results and discussion
Photocatalyst preparation and characterization
peripheral framework positions of additional chromophores or
metallic complexes such as ruthenium(II) polypyridyl com-
plexes have also been applied.1,2,5 In this context, although
MOFs with phthalocyanine units as organic linkers have been
MIL-101(Cr)-NH2 was selected in the present study as a host
for SubPc-Cl for various reasons, including framework robust-
ness, the presence of –NH2 groups as apical binding sites for
SubPc-Cl, large porosity, high surface area and reliable
synthesis.15–17 The amino groups present in the terephthalate
linkers are expected to act as binding sites for the apical posi-
tion of SubPc-Cl, replacing Cl−.18,19 It is expected that the
substitution of Cl− in SubPc-Cl by the amino groups located
in the MOF cavities would result in the formation of a
strongly bound composite that could exhibit visible light photo-
response due to the optical properties of SubPc.20–23 Therefore,
MIL-101(Cr)-NH2 appears to be a preferred porous host
to incorporate SubPc-Cl in comparison to the parent
aDepartamento de Química, Universitat Politècnica de València, C/Camino de Vera,
s/n, 46022 Valencia, Spain. E-mail: hgarcia@qim.upv.es
bInstituto Universitario de Tecnología Química, CSIC-UPV,
Universitat Politécnica de Valencia, Av. de los Naranjos, Valencia 46022, Spain
cCenter of Excellence for Advanced Materials Research, King Abdulaziz University,
Jeddah, Saudi Arabia
†Electronic supplementary information (ESI) available: Additional character-
ization and catalytic data. See DOI: 10.1039/C9DT04004H
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Scheme 1 (a) The structure of SubPc-Cl and its covalent linkage (red
bond) with the –NH2 groups present in the terephthalate organic ligand
Fig. 1 The XRD patterns of (a) MIL-101(Cr)-NH2, (b) SubPc@MIL-101(Cr)-
of MIL-101(Cr)-NH2; (b)
a cartoon illustrating the structure of
NH2 and (c) SubPc-Cl.
SubPc@MIL-101(Cr)-NH2 (red sphere: pore; blue spheres: Cr clusters;
and black sphere: MIL101(Cr)-NH2). Note that the NH2 groups in tere-
phthalate linkers play the role of apical coordination sites for SubPc.
The presence of SubPc as the guest incorporated into
MIL-101(Cr)-NH2 can be assessed by using diffuse reflectance
UV-vis absorption spectra, in which the presence of a new
band with a λmax of about 570 nm, attributable to the presence
of SubPc, can be observed. Fig. 2 shows a comparison of the
diffuse reflectance UV-vis spectra of MIL-101(Cr)-NH2 and
those of the composite SubPc@MIL-101(Cr)-NH2. Fig. S2†
shows the diffuse reflectance UV-visible spectra of SubPc-Cl.
Comparison of the visible band corresponding to the occluded
SubPc with that of the parent SubPc-Cl shows a clear red shift
of the adsorption band from 495 to 575 nm. This notable shift
can be attributed to the exchange of chloride as an apical
ligand with the aromatic amino group, in agreement with the
success of SubPc-Cl adsorption by strong interaction with the
amino groups.
MIL-101(Cr), in which such binding groups in the MOF linkers
are not present. Scheme 1 illustrates the incorporation procedure
and the anchoring of SubPc-Cl through the –NH2 substituents.
After incorporation of SubPc-Cl into MIL-101(Cr)-NH2, iso-
thermal gas adsorption measurements reveal a large decrease
in the surface area value and a diminution of the porosity
(Table 1).
The amount of SubPc adsorbed on MIL-101(Cr)-NH2 was
estimated by the combustion elemental analysis of carbon and
nitrogen and from the comparison of the thermogravimetric
profiles of MIL-101(Cr)-NH2 and SubPc@MIL-101(Cr)-NH2.
The data are also given in Table 1, while Fig. S1 in the ESI†
shows the thermogravimetric profiles of these two solids,
where it can be seen that the percentage of residual weight
after decomposition of the organic components is larger for
SubPc@MIL-101(Cr)-NH2 as compared to MIL-101(Cr)-NH2.
Analytical data indicate that the percentage of the subphthalo-
cyanine guest in the composite material corresponds to about
2 wt%.
Coincident conclusions can be achieved by the analysis of
the peaks corresponding to the different elements in XPS.
Fig. 3 summarizes the most characteristic data obtained by
XPS, while Fig. S3–S5 in the ESI† provide additional infor-
The XRD pattern of SubPc@MIL-101(Cr)-NH2 is coincident
with that of MIL-101(Cr)-NH2, indicating that the crystal struc-
ture of the MOF is preserved upon adsorption of SubPc-Cl. The
absence of characteristic peaks corresponding to SubPc-Cl in
the XRD pattern of the SubPc@MIL-101(Cr)-NH2 composite
indicates that no crystals of the boron macrocycle are detect-
able in the guest, this being compatible with site isolation of
individual SubPc macrocycles inside the host cavities (Fig. 1).
Table 1 Isothermal N2 adsorption and relevant elemental analysis of
MIL-101(Cr)-NH2 and SubPc@MIL-101(Cr)-NH2
MIL-101(Cr)-NH2 SubPc@MIL-101(Cr)-NH2
BET surface area (m2 g−1
)
1950
2
490
0.6
Pore volume (cm3 g−1
)
Fig. 2 The diffuse reflectance UV-vis spectra of MIL-101(Cr)-NH2 (red
line) and SubPc@MIL-101(Cr)-NH2 (blue line).
N (%)
C (%)
3.2
22.2
4.9
32.1
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Fig. 4 The time-conversion plot of the hydrogenative debromination
■
of α-bromoacetophenone to acetophenone using ( ) MIL-101(Cr)-NH2,
□
●
(
) SubPc@MIL-101(Cr)-NH2 and ( ) without any catalyst. Reaction con-
ditions: α-bromoacetophenone (1 mmol), TEOA (10 µL), CH3CN (3 mL)
and MOF (10 mg, 5.1 × 10−4 mmol SubPc).
Fig. 3 XPS spectra of MIL-101(Cr)-NH2 (black line), SubPc@MIL-101(Cr)-
NH2 (red line) and SubPc-Cl (blue line).
α-bromoacetophenone into acetophenone was achieved this
time. It should be noted that the reaction does not take place
in the dark, without visible light irradiation.
The photocatalytic stability of the composite was studied by
performing consecutive runs. Fig. 5 shows the temporal pro-
files of the photoredox debromination activity upon reuse of
the same SubPc@MIL-101(Cr)-NH2 sample. The results show
that the photoredox activity is maintained with only a slight
decay from 90 to 83% after 4 uses.
mation on the XPS peaks for each element. The most salient
feature detected by XPS analysis is the observation of
additional signals for
B 1s and Cl 2p present in the
SubPc@MIL-101(Cr)-NH2 composite with respect to the pris-
tine MIL-101(Cr)-NH2 host, indicating the presence of SubPc
in the material. Interestingly, the B 1s peak is split into two
individual components that can be attributed to B atoms inter-
acting with the amino groups of the linker and with the Cl−
anions. This interpretation agrees with the presence of Cl in
the SubPc@MIL-101(Cr)-NH2 composite, indicating that no
complete replacement of the apical Cl ligand by NH2 has
occurred during the adsorption.
Photoredox catalysis
As commented in the introduction, the purpose of this study
was to show that the adsorption of SubPc-Cl onto MIL-101(Cr)-
NH2 as a light harvesting centre affords photoredox activity
with enhanced visible light photoresponse for hydrogenative
debromination of α-bromoacetophenone (Fig. 4a).
Initial experiments were carried out with simulated sun-
light in acetonitrile using triethanolamine (TEOA) as the elec-
tron donor. The results of the photoredox test are presented in
Fig. 4. As can be seen in this figure, while negligible conver-
sion is observed in the absence of any photocatalyst, the use
of MIL-101(Cr)-NH2 results only in 15% debromination at 8 h
of irradiation. In contrast, using SubPc@MIL-101(Cr)-NH2
Fig. 5 The time-conversion plot of the hydrogenative debromination of
α-bromoacetophenone to acetophenone upon consecutive reuses
using SubPc@MIL-101(Cr)-NH2 as a photoredox catalyst. Legend: ( ) 1st
■
□
●
○
use ( ) 2nd use, ( ) 3rd use and ( ) 4th use. Reaction conditions:
α-Bromoacetophenone (1 mmol), TEOA (10 µL), CH3CN (3 mL) and MOF
as the photoredox catalyst,
a
complete conversion of (10 mg, 5.1 × 10−4 mmol SubPc).
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The SubPc@MIL-101(Cr)-NH2 composite was also efficient
at promoting α-dechlorination of chloroacetophenone,
although comparison of the temporal profiles of the bromo-
Experimental
Materials
and chloro-derivatives shows that the reaction is slower in the All the reagents and solvents used in the present paper were of
case of α-chloroacetophenone, in accordance with the higher analytical or HPLC grade and supplied by Sigma-Aldrich.
bond strength of C–Cl with respect to C–Br. Fig. S6 in the ESI†
Catalyst preparation
shows a comparison of the photocatalytic activity for dechlori-
nation with respect to debromination.
MIL-101(Cr)-NH2 preparation: MIL-101(Cr)-NO2 was prepared
The fact that the reaction mechanism involves the gene- following already reported procedures.16,17 Briefly, nitro-
ration of the α-ketyl radicals was confirmed by quenching of terephthalic acid (1.5 mmol) and CrCl3 (1 mmol) were introduced
these radicals by 2,2,4,4-tetramethylpiperidinyloxy (TEMPO). into a Teflon autoclave containing demineralized water (8 mL).
Thus, if the photoredox debromination under simulated sun- Then, the autoclave was heated at 180 °C for 120 h. Once the
light irradiation using the SubPc@MIL-101(Cr)-NH2 composite autoclave was cooled to room temperature, the precipitate
is started under conventional reaction conditions and then formed in the process was washed several times with dimethyl-
after 2 h of reaction, TEMPO is added to the reaction mixture formamide (DMF) at 120 °C and then with ethanol at 80 °C.
no further progress in the formation of acetophenone is Then, MIL-101(Cr)-NO2 was subjected to post-synthetic modifi-
observed. Fig. S7† compares the temporal profiles of the cation using SnCl2·H2O as the reducing agent leading to
photocatalytic debromination in the absence and in the pres- the formation of MIL-101(Cr)-NH2 according to reported
ence of TEMPO.
procedures.16,17
Finally, the solar light photoresponse of SubPc@MIL-101
SubPc@MIL101(Cr)-NH2 preparation: boron chloride sub-
(Cr)-NH2 was also applied for the photocatalytic coupling phthalocyanine (SubPc-Cl) was synthesized following reported
of α-bromoacetophenone and styrene to
form literature procedures.18,24 Then, MIL101(Cr)-NH2 (60 mg) was
α-phenylbutyrophenone, by irradiating with simulated sun- thermally activated by heating at 150 °C under vacuum in a 3
light. In this photoredox reaction, the α-ketyl radical should necked round bottomed flask connected to a reflux condenser
add to the CvC double bond of styrene, since this vinylic sub- for 22 h. SubPc-Cl (6 mg) was dissolved in dry toluene (6 mL)
strate can easily undergo attack by radicals as previously and the solution was added to the flask containing the active
reported.25 It is interesting to note that although the conver- MOF. The suspension was then refluxed under an inert atmo-
sion was not high, the selectivity for α-phenylbutyrophenone sphere for 48 h. The dispersion was filtered under vacuum and
was almost complete. It should be mentioned that also in this washed with toluene, and the resulting solid was subsequently
case the reaction does not occur in the dark without visible subjected to Soxhlet extraction using chloroform (150 mL) as
light irradiation. Fig. 6 shows the temporal profile of butyro- solvent for 12 h.
phenone formation.
Catalyst characterization
Powder X-ray diffraction (PXRD) of the materials was per-
formed on a Philips XPert diffractometer equipped with a
graphite monochromator (40 kV and 45 mA) employing Ni fil-
tered CuKα radiation. N2 adsorption isotherms at 77 K were
recorded using
a
Micromeritics ASAP 2010 device.
Thermogravimetric analyses were performed on
a
TGA/
SDTA851e METTLER TOLEDO station. The X-ray photoelectron
spectra (XPS) of different solids were collected on a SPECS
spectrometer equipped with a MCD-9 detector using a mono-
chromatic Al (Kα = 1486.6 eV) X-ray source for calibrating the
binding energy based on the C 1s peak set at 284.4 eV as refer-
ence. CASA software has been employed for spectral deconvo-
lution. Diffuse reflectance UV-visible spectra were recorded
using a Cary 5000 Varian spectrophotometer having an inte-
grating sphere; the sample as compressed powder was placed
in a sample holder.
Catalytic experiments
The required amount of catalyst (10 mg) was introduced into a
quartz tube containing acetonitrile (3 mL) dissolved in
α-bromoacetophenone (1 mmol) and TEOA (10 µL) and the
system was purged with Ar. Then, the tube was irradiated with
a solar simulator. The reactions were magnetically stirred and
Fig. 6 The
time-conversion
plot
of
the
coupling
of
α-bromoacetophenone and styrene using SubPc@MIL-101(Cr)-NH2 as a
photoredox catalyst. Reaction conditions: α-Bromoacetophenone
(1 mmol), styrene (1 mmol), CH3CN (3 mL) and MOF (10 mg, 5.1 × 10−4
mmol SubPc).
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reaction aliquots were sampled at the corresponding reaction and Generalitat Valenciana (Prometeo 2017-083) is gratefully
times. acknowledged. S. N. is thankful for the financial support from
In the reusability experiments, the SubPc@MIL-101(Cr)- the Fundación Ramón Areces (XVIII Concurso Nacional para
NH2 solid was recovered at the end of the reaction by filtration la Adjudicación de Ayudas a la Investigación en Ciencias de
(nylon filter, 0.2 µm). Then, the catalyst was transferred to a la Vida y de la Materia, 2016), the Ministerio de Ciencia,
round-bottom flask (50 mL) and subjected to ethanol washing Innovación y Universidades RTI 2018-099482-A-I00 project and
(20 mL) under magnetic stirring for 30 min. This procedure the Generalitat Valenciana grupos de investigación consolid-
was repeated two more times. The final solid was recovered by ables 2019 (ref: AICO/2019/214) project. S. R.-B. also thanks
filtration (nylon filter, 0.2 µm) and dried in an oven.
the Research Executive Agency (REA) and the European
The coupling of α-bromoacetophenone and styrene was per- Commission for the funding received under the Marie
formed by dissolving 10 mg of the catalyst in 3 mL of aceto- Skłodowska Curie actions (H2020-MSCA-IF-2015/Grant agree-
nitrile containing 1 mmol of α-bromoacetophenone and ment number 709023/ZESMO).
1 mmol of styrene. The solution was placed in a quartz test
tube sealed with a septum cap. Then, the system was purged
with argon. Subsequently, the reaction tube was irradiated
with a solar simulator. The reaction was magnetically stirred
Notes and references
and reaction aliquots were sampled at the corresponding reac-
tion times.
1 X. Deng, Z. Li and H. García, Chem. – Eur. J., 2017, 23,
11189–11209.
2 A. Dhakshinamoorthy, A. M. Asiri and H. García, Angew.
Chem., Int. Ed., 2016, 55, 5414–5445.
Product analysis
Previously filtered reaction aliquots were diluted in an aceto-
nitrile solution containing a known amount of nitrobenzene
as the external standard. The aliquots were immediately ana-
lyzed by gas chromatography (GC) using a flame ionization
detector. Quantification was carried out based on calibration
plots obtained with authentic samples against nitrobenzene.
Reaction products were identified using a GC (Hewlett Packard
HP6890 Chromatograph) coupled to a mass spectrometer (MS,
Agilent 5973). In addition, acetophenone formation was con-
firmed by co-injection in the gas chromatograph with a com-
mercial sample.
3 D. Jiang, P. Xu, H. Wang, G. Zeng, D. Huang, M. Chen,
C. Lai, C. Zhang, J. Wan and W. Xue, Coord. Chem. Rev.,
2018, 376, 449–466.
4 R. Li, W. Zhang and K. Zhou, Adv. Mater., 2018, 30, 1705512.
5 J. Qiu, X. Zhang, Y. Feng, X. Zhang, H. Wang and J. Yao,
Appl. Catal., B, 2018, 231, 317–342.
6 L. Shen, R. Liang and L. Wu, Chin. J. Catal., 2015, 36, 2071–
2088.
7 Y. Shi, A.-F. Yang, C.-S. Cao and B. Zhao, Coord. Chem. Rev.,
2019, 390, 50–75.
8 S. Wang and X. Wang, Small, 2015, 11, 3097–3112.
9 M. Wen, K. Mori, Y. Kuwahara, T. An and H. Yamashita,
Chem. – Asian J., 2018, 13, 1767–1779.
Conclusions
10 S. Das and W. M. A. Wan Daud, Renewable Sustainable
Energy Rev., 2014, 39, 765–805.
The present study shows that adsorption of subphthalocyanine
at a loading of about 2 wt% inside a robust MOF having amino
groups in the terephthalate linker as binding sites renders
a composite with solar light photoresponse that is able to
promote hydrogenative dehalogenation of α-haloacetophenones.
The reaction involves ketyl radicals and the catalyst can be
reused with only minor decay in its photocatalytic activity.
Since compared to related phthalocyanines, subphthalocya-
nines have been much less used as light harvesters and photo-
sensitizers, the present study illustrates the potential that this
boron macrocycle can have in photoredox catalysis.
11 B. del Rey, U. Keller, T. Torres, G. Rojo, F. Agulló-López,
S. Nonell, C. Martí, S. Brasselet, I. Ledoux and J. Zyss,
J. Am. Chem. Soc., 1998, 120, 12808–12817.
12 C. G. Claessens, D. González-Rodríguez and T. Torres,
Chem. Rev., 2002, 102, 835–853.
13 N. Kobayashi, in The Porphyrin Handbook, ed. K. M. Kadish,
K. M. Smith and R. Guilard, Academic Press, Amsterdam,
2003, pp. 161–262.
14 A. Santiago-Portillo, H. G. Baldoví, E. Carbonell,
S. Navalón, M. Alvaro, H. García and B. Ferrer, J. Phys.
Chem. C, 2018, 122, 29190–29199.
15 G. Ferey, C. Mellot-Draznieks, C. Serre, F. Millange,
J. Dutour, S. Surble and I. Margiolaki, Science, 2005, 309,
2040–2042.
Conflicts of interest
16 A. Santiago-Portillo, J. F. Blandez, S. Navalón, M. Álvaro
and H. García, Catal. Sci. Technol., 2017, 7, 1351–1362.
17 A. Santiago-Portillo, S. Navalón, P. Concepción, M. Álvaro
and H. García, ChemCatChem, 2017, 9, 2506–2511.
18 C. G. Claessens, D. Gonzalez-Rodriguez, M. S. Rodriguez-
Morgade, A. Medina and T. Torres, Chem. Rev., 2014, 114,
2192–2277.
There are no conflicts to declare.
Acknowledgements
Financial support from the Spanish Ministry of Economy and
Competitiveness (Severo Ochoa and RTI2018-098237-B-C21)
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19 J. Guilleme, L. Martínez-Fernández, D. González- 22 G. E. Morse and T. P. Bender, ACS Appl. Mater. Interfaces,
Rodríguez, I. Corral, M. Yáñez and T. Torres, J. Am. Chem.
Soc., 2014, 136, 14289–14298.
20 M. Managa, J. Mack, D. Gonzalez-Lucas, S. Remiro-
Buenamañana, C. Tshangana, A. N. Cammidge and
2012, 4, 5055–5068.
23 K. L. Sampson, X. Jiang, E. Bukuroshi, A. Dovijarski,
H. Raboui, T. P. Bender and K. M. Kadish, J. Phys. Chem. A,
2018, 122, 4414–4424.
T. Nyokong, J. Porphyrins Phthalocyanines, 2015, 20, 1– 24 C. G. Claessens, D. Gonzalez-Rodriguez, B. del Ray, T. Torres,
20.
G. Mark, H.-P. Schuchmann, C. von Sonntag, J. G. MacDonald
21 G. Bressan, A. N. Cammidge, G. A. Jones, I. A. Heisler,
and R. S. Nohr, Eur. J. Org. Chem., 2003, 2547–2551.
D. Gonzalez-Lucas, S. Remiro-Buenamañana and 25 E. Speckmeier, P. J. W. Fuchs and K. Zeitler, Chem. Sci.,
S. R. Meech, J. Phys. Chem. A, 2019, 123, 5724–5733. 2018, 9(35), 7096–7103.
17740 | Dalton Trans., 2019, 48, 17735–17740
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