Angewandte Chemie International Edition
10.1002/anie.201907015
COMMUNICATION
Table 1 Comparison of catalytic efficiency for the formylation of amine.
quadrupole interaction between the polarizable CO
and the F-Phos-POP-1 framework (Figure S11B).
2
molecules
Cat.
Herein, F-Phos-POP-1 supported by Ru species (denoted as
Ru/F-Phos-POP-1) was used as an example to verify the
+ CO + H
2
2
1
a
2a
catalytic efficiency of the obtained material in CO
Ru/F-Phos-POP-1 was obtained by simply treating F-Phos-POP-
polymer with RuCl in ethanol (for details, see Supporting
Information). The Ru content was determined to be 0.46 wt%
2
transformation.
-
1
Catalyst
TOF of 2a (h )
Ref.
Ru/F-Phos-POP-1
Ru/Phos-POP
Ru/F-Phos-POP-2
Car-CMP-1@Ru
Imine-POP@Pd
101
43
204
8
18
44
18
8
This work
This work
1
3
-
1
-1
(
0.045 mmol Ru g ) and 0.41 wt% (0.041 mmol Ru g ) in
Ru/Phos-POP and Ru/F-Phos-POP-1, respectively, as detected
by ICP-OES. The Ru3d XPS spectrum shows that Ru species
with both +2 (Ru3d5/2: 281.1 eV, R3d3/2: 285.4 eV) and +3
Au/TiO
2
Pd/Al O -NR-RD
2
3
Pd/C(OH)
Pd-Au/PANI-CNT
Ru3d5/2: 282.4 eV, R3d3/2: 286.7 eV) state are present (Figure
2
S12).[ In addition, the TEM images support a homogeneous
ruthenium loading without detectable Ru clusters or
nanoparticles in the materials (Figure S13, SI).
In summary,
a novel two-step synthetic pathway was
developed for the preparation of phosphabenzene-functionalized
porous polymers. The synthesis was conducted under metal-
free conditions and without the need for the synthesis of
phosphine-based monomers. Importantly, our method allows a
straightforward way to achieve the multi-functionalization of
Subsequently, the catalytic performances of Ru/Phos-POP
and Ru/F-Phos-POP-1 were examined in the formylation
reaction of amines with a CO /H mixture. As shown in Table 1,
2 2
although heterogeneous catalytic systems composed of metal
species and polymer have been reported previously, primarily
with carbon or metal oxide supports, the catalytic efficiencies of
these systems are generally unsatisfactory. The highest TOF is
organic
phosphorine-based
polymers.
Fluorinated
phosphabenzene-containing POPs were synthesized by simply
adopting fluoro-containing aromatic aldehyde monomers as
starting materials. After the introduction of fluorine atoms into the
framework, the resultant polymer F-Phos-POPs showed a much
only 44 h-1 using Au/TiO
model substrate, after a survey of the reaction parameters
Table S2, SI), N-formyl morpholine (2a) was obtained at a 97%
2
. Employing morpholine (1a) as a
(
2
higher CO uptake capacity compared with their nonfluorinated
yield using Ru/F-Phos-POP-1 with a catalyst loading of only 0.04
mol% based on Ru species and 1,3-dimethyl-2-imidazolidinone
as a solvent in the presence of t-BuOK at 100 oC (entry 10).
Notably, this result is in stark contrast to the performance of the
nonfluorinated Ru/Phos-POP catalyst (2a yield: 47%) under
otherwise identical conditions (entry 14). A TOF value of 101 h-1
was obtained in the catalytic system consisting of Ru/F-Phos-
POP-1. To the best of our knowledge, this represents the
highest TOF value among the heterogeneous catalytic systems
reported in the literature to date (Table 1). We hypothesized that
a structurally similar F-Phos-POP-2 based system would show
even higher catalytic activity as heterogeneous catalyst because
of the presence of a larger number of fluorine substituents and a
larger proportion of mesopores. Ru/F-Phos-POP-2 was
prepared using a similar procedure with a Ru content of 0.40
analogue. After coordination with Ru species, Ru/F-Phos-POP
exhibited high efficiency for the formylation of amines with a
CO /H mixture, as well as exhibiting excellent stability, easy
2 2
recyclability and maintaining high catalytic activity. This work
provides new insight into designing and fabricating organic
phosphine-based porous polymers, extending their application in
transition metal-based heterogeneous catalysis.
Acknowledgments
The research was supported financially by the Division of
Chemical Sciences, Geosciences, and Biosciences, Office of
Basic Energy Sciences, US Department of Energy.
-
1
wt % (0.040 mmol g ) as determined by ICP-OES. Notably,
reducing the reaction time to only 12 h decreased the yield of 2a
to 73% using Ru/F-Phos-POP-1 as a catalyst (entry 13), whears
a nearly quantitative yield (97%) was achieved in the case of the
Ru/F-Phos-POP-2 system, showing a TOF of 204 h-1 (entry 16).
Keywords: porous organic polymers • pyrylium ion •
phosphabenzene • fluorine • carbon dioxide
[
[
[
1] L.-W. Ye, J. Zhou, Y. Tang, Chem. Soc. Rev. 2008, 37, 1140-1152.
2] Z. Wang, X. Xu, O. Kwon, Chem. Soc. Rev. 2014, 43, 2927-2940.
3] M. P. Duffy, W. Delaunay, P. A. Bouit, M. Hissler, Chem. Soc. Rev. 2016,
We propose that the synergistic effect of abundant CO
2
-philic F
45, 5296-5310.
sites and high phosphabenzene content in the polymer
[
4] S. Rothemund, I. Teasdale, Chem. Soc. Rev. 2016, 45, 5200-5215.
backbone played crucial role in achieving the superior CO
2
[5] Y. Qin, L. Zhu, S. Luo, Chem. Rev. 2017.
[6] Y. Park, Y. Kim, S. Chang, Chem. Rev. 2017, 117, 9247-9301.
[
[
7] Q.-L. Zhou, Angew. Chem. Int. Ed. 2016, 55, 5352-5353.
8] A. N. Desnoyer, J. A. Love, Chem. Soc. Rev. 2017, 46, 197-238.
Additionally, Ru/F-Phos-POP-2 showed good reusability,
confirmed by the fact that a 94% yield of 2a was still achieved
even after the catalyst was reused five times (Figure S14). No
Ru species were detected in the filtrate of the reaction mixture
according to ICP-OES analysis (<10 ppb), indicating the strong
coordination ability of phosphabenzene functionalities within the
polymer backbone with Ru species. In the presence of Ru/F-
Phos-POP-2, the N-formylation reactions proceeded smoothly
using other primary and secondary aliphatic amines as
substrates, selectively affording the corresponding formamides
[9] R.-H. Li, X.-M. An, Y. Yang, D.-C. Li, Z.-L. Hu, Z.-P. Zhan, Org. Lett. 2018,
0, 5023-5026.
2
[
[
[
[
10] Z.-C. Ding, C.-Y. Li, J.-J. Chen, J.-H. Zeng, H.-T. Tang, Y.-J. Ding, Z.-P.
Zhan, Adv. Synth. Catal. 2017, 359, 2280-2287.
11] C. Li, W. Wang, L. Yan, Y. Wang, M. Jiang, Y. Ding, J. Mater. Chem. A
2016, 4, 16017-16027.
12] Q. Sun, Z. Dai, X. Liu, N. Sheng, F. Deng, X. Meng, F.-S. Xiao, J. Am.
Chem. Soc. 2015, 137, 5204-5209.
13] Z. Yang, B. Yu, H. Zhang, Y. Zhao, Y. Chen, Z. Ma, G. Ji, X. Gao, B. Han,
Z. Liu, ACS Catal. 2016, 6, 1268-1273.
[14] K. Wang, L. G. Meng, L. Wang, Org. Lett. 2017, 19, 1958-1961.
[
[
[
15] J. Wu, L. He, A. Noble, V. K. Aggarwal, J. Am. Chem. Soc. 2018, 140,
0700-10704.
16] D. Moser, Y. Duan, F. Wang, Y. Ma, M. J. O'Neill, J. Cornella, Angew.
Chem. Int. Ed. 2018, 57, 11035-11039.
1
2
a~2n at an excellent yield (87~97%) (Scheme S1, SI).
17] M. Oschatz, M. Antonietti, Energy Environ. Sci. 2018, 11, 57-70.
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