Click reaction in the synthesis of novel thiophosphorylated ligands for electrochemical hydrogen evolution

Article abstract of DOI:10.1016/j.mencom.2019.07.009

O-Propargylation of free hydroxyl groups in calix[4]resorcinols bearing thiophosphoryloxyphenyl substituents at the lower rim and possessing cone or chair conformations afforded new derivatives containing eight terminal alkyne groups. Their subsequent click reaction with azidomethylarenes led to the corresponding multifunctional triazole calix[4]resorcinols. Nickel complexes with such ligands show catalytic activity in hydrogen evolution reaction providing the decrease in potential of the direct acid reduction on glassy carbon electrode of 0.98 V.

Full text of DOI:10.1016/j.mencom.2019.07.009

Mendeleev
Communications
Mendeleev Commun., 2019, 29, 388–390
Click reaction in the synthesis of novel thiophosphorylated
ligands for electrochemical hydrogen evolution
Irina R. Knyazeva,*a Victoria I. Matveeva,a Vera V. Khrizanforova,a Victor V. Syakaev,a
Yulia H. Budnikova,a Wolf D. Habicherb and Alexander R. Burilova
a A. E. Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center of the Russian
Academy of Sciences, 420088 Kazan, Russian Federation. Fax: +7 843 273 4872; e-mail: ihazieva@mail.ru
b Institute of Organic Chemistry, Dresden University of Technology, D-01062 Dresden, Germany
DOI: 10.1016/j.mencom.2019.07.009
R2
R2
O-Propargylation of free hydroxyl groups in calix[4]resorcinols
bearing thiophosphoryloxyphenyl substituents at the lower
rim and possessing cone or chair conformations afforded new
derivatives containing eight terminal alkyne groups. Their
subsequent click reaction with azidomethylarenes led to the
corresponding multifunctional triazole calix[4]resorcinols.
Nickel complexes with such ligands show catalytic activity in
hydrogen evolution reaction providing the decrease in potential
of the direct acid reduction on glassy carbon electrode of
0.98 V.
N
N
N
N
R1
R1
N
N
N
N
R2
N
R2
HO
OH
O
O
N
N
N
R1
N
X
X
X
X
X
X
HO
R1
HO
OH
OH
O
O
2 steps
R1
R1
O
O
X
X
N
R2
N
N
R2
HO
OH
O
O
N
N
R1
R1
N
N
R1 = H, Me
R2 = PhCH2,
N
N
S
Me
Me
O
O
N
R2
N
R2
X =
P O
(anthracen-9-yl)methyl
Calix[4]resorcinols are relatively accessible macrocyclic com-
pounds suitable for functionalization at ortho-positions of
aromatic rings, hydroxyl groups on the upper rim of molecule,
and functional substituents on a calixarene framework. Structural
modification of calix[4]resorcinols by various functional groups
alters selectivity and/or enhances the binding efficiency of different
substrates along with an increase in their solubility, which extends
potential applications of these macrocyclic ligands.1–3
Hydrolytically stable macrocycles with P–C bonds are most
promising for further use. We previously synthesized new calix[4]-
resorcinols bearing hydrolytically stable thiophosphoryl group
as a substituent through the condensation of resorcinol and its
derivatives with properly functionalized hydroxybenzaldehydes.4–7
Nickel complexes of such compounds turned to be effective
catalysts of electrochemical molecular hydrogen evolution from
acid solutions.8–10 We recently discovered that the modification of
thiophosphorylated calix[4]resorcinols by aminomethyl groups
via Mannich reaction improves the characteristics of such catalytic
process and makes it possible to create even more effective
catalytic systems with the maximum gain in energy.11 To extend
these studies, we suggested that functionalization of thiophos-
phorylated calix[4]resorcinols using popular click reaction12–14
would provide derivatives with improved catalytic performance
in question.
was monitored by MALDI mass spectrometry and was stopped
as soon as the mass spectrum showed only one peak for the
corresponding target macrocycle (~24 h). Subsequent click
reaction of compounds 2a–c withbenzyl azideor 9-(azidomethyl)
anthracene in THF/H2O (1:1) in the presence of CuSO4 /sodium
ascorbate catalytic system at heating (60–65°C, 24 h) gave
novel calix- [4]resorcinols 3a–d in yields up to 94% (see Scheme
1). The structures of synthesized compounds were proved by
NMRspectroscopy(1H,13C,and31P),MALDImassspectrometry
and elemental analysis. The IR spectra of target products do not
exhibit intrinsic absorption bands of CºC and CºC–H groups,
which confirms the completion of the reaction.†
Note that NMR spectra of products 2a,b, 3a,b,d, which arise
from the upper-rim modification of calixarenes 1a,b in cone
conformation as starting compounds, indicate the boat conforma-
tion. This is a general feature when bulky substituents are present
in calixarene, and it is well documented.4–6,15–18 In our case,
there is a strong broadening of the signals for the protons and
carbon atoms of resorcinol residues of a calixarene scaffold.
In addition, in the case of bulky substituents, the situation is
complicated by different opening angles of phenolic groups of
the calixarene platform, which depend on the spatial arrangement
of substituents. All these factors result in the variable chemical
shifts of the signals in NMR spectra as observed in case of
compound 3d.
In this work, novel triazole-containing derivatives of thio-
phosphorylated calix[4]resorcinols were obtained employing the
click reaction and catalytic activity of nickel complexes of the
synthesized ligands in electrochemical hydrogen evolution from
acid solutions was tested. O-Alkylation of calix[4]resorcinols
1a,b and 1c in cone and chair conformations, respectively, with
propargyl bromide in the presence of freshly calcined K2CO3
afforded new calix[4]resorcinols 2a–c bearing eight alkyne
terminal groups in up to 99% yields (Scheme 1). The reaction
During analogous transformations of macrocycle 1c, its chair
conformation remains in all the products. Doubling of the signals
for the protons of aromatic rings of resorcinol residues in calix-
[4]resorcinols possessing both boat and chair conformations
1
can be observed in H and 13C NMR spectra, which indicates
†
For the synthesis and characteristics of compounds obtained, see
Online Supplementary Materials.
© 2019 Mendeleev Communications. Published by ELSEVIER B.V.
on behalf of the N. D. Zelinsky Institute of Organic Chemistry of the
Russian Academy of Sciences.
– 388 –

Mendeleev Commun., 2019, 29, 388–390
R2
R2
N
N
N
N
R1
R1
R1
N
N
N
N
R2
HO
OH
R2
O
O
O
O
N
N
N
N
R1
N
X
X
X
X
X
X
X
X
X
X
HO
R1
HO
OH
OH
O
O
O
O
O
O
i
ii
R1
R1
R1
R1
O
O
X
X
O
O
R2
N
N
N
R2
HO
OH
O
O
N
N
R1
R1
R1
N
N
N
N
77–99%
N
N
1a R1 = H, rccc-isomer, cone
1b R1 = Me, rccc-isomer, cone
1c R1 = Me, rctt-isomer, chair
2a R1 = H, rccc-isomer, boat
2b R1 = Me, rccc-isomer, boat
2c R1 = Me, rctt-isomer, chair
R2
R2
71–94%
3a R1 = H, R2 = PhCH2, rccc-isomer, boat
3b R1 = Me, R2 = PhCH2, rccc-isomer, boat
3c R1 = Me, R2 = PhCH2, rctt-isomer, chair
S
Me
X =
Me
O
O
P O
3d R1 = Me, R2 =
, rccc-isomer, boat
CH2
Scheme 1 Reagents and conditions: i, BrCH2CºCH, K2CO3, MeCN, reflux; ii, ArCH2N3, CuSO4·5H2O, sodium ascorbate, THF/H2O, reflux.
different, horizontal (h) and vertical (v), arrangement of opposite
aromatic fragments relative to the macrocycle plane as for thio-
phosphorylated calix[4]resorcinols in our previous publications.4–7
Extensive studies in recent decades were aimed at the search
for new high-performance catalytic systems for electrochemical
hydrogen evolution in order to develop accessible and inexpensive
catalysts for hydrogen energetics.19–33 We recently showed that
nickel complexes of thiophosphorylated calix[4]resorcinols including
starting compounds 1a–c, as well as their aminomethyl derivatives,
were effective catalysts of electrochemical hydrogen evolution
from acids.8–11 The herein obtained new triazole-containing ligands
3a,b,d were converted to the appropriate nickel complexes by
analogy with the previously described8 in situ reaction between
equimolar amounts of a ligand and Ni(BF4)2. Using cyclic volt-
ammetry, their catalytic activity in electrochemical hydrogen
evolution from trifluoroacetic acid was studied.‡ It was determined
that in the case of complexes with ligands 3a,b, the reduction
potentials of Niii to Ni0 approached –1.15 V vs. Ag/AgCl (Figure 1).
Addition of proton donor (trifluoroacetic acid) to the solution of
these complexes results in a catalytic current at the potential of
nearly –1.12 V, which leads to the shift of the potential to anodic
region by 60 mV (in the ligand 3b) and 120 mV (3a) as compared
to the catalytic potential of their precursors 1b and 1a, respec-
tively. However, in this case, the catalytic efficiency is 0.04,18
what allows one to consider the complex as the effective catalyst
of this reaction. In addition, hydrogen is evolved on the surface
of working electrode. The difference of the potentials between
catalytic peak and the peak of heterogeneous reduction of
trifluoroacetic acid on electrode amounts to 0.98 V in this case.
In the nickel complex of ligand 3d, a reduction peak locates
at more cathodic potential of –1.5 V (vs. Ag/AgCl). A current
increasing is detected at the potential of –1.5 V in the presence of
10 mm (10 equiv.) of proton donor, and a further shift of the
potential to cathodic range with an increase in the concentration
of acid is observed, which renders this catalytic system the least
attractive in this study.
1:12
1:9
In conclusion, this work demonstrates that thiophosphorylated
calix[4]resorcinols can be easily and effectively modified via click
reaction to afford new highly functionalized triazole-containing
derivatives in high yields. Incorporation of triazole-containing
functional groups to thiophosphorylated calix[4]resorcinol can
cause the shift of the potential of catalytic hydrogen reduction
to more anodic range (as compared to unsubstituted precursors)
and lead to an increase in the difference between the potentials of
catalytic peak and heterogeneous reduction of acid on electrode
up to 0.98 V thus facilitating reduction on a nickel center. Triazole-
containing calixarene ligands reveal higher catalytic activity vs.
unmodified precursors, which seems promising for development
of new high-performance catalytic systems for electrochemical
hydrogen evolution processes.
1:6
1:3
[acid]
100 µA
1:0
0
–0.2
–0.4
–0.6
–0.8
–1.0
–1.2
–1.4
Potential/V (vs. Ag/AgCl)
Figure 1 CVs of 1 mm Ni(BF4)2 with 3b (1:1) in DMF in the presence of
increasing amounts of TFA. Conditions: working electrode is glassy carbon,
auxiliary electrode is Pt, supporting electrolyte is Bu4NBF4.
This work was supported by the Russian Foundation for Basic
Research (grant no. 16-03-00201 a). The authors are grateful to
the Spectral-Analytical Center of FRC Kazan Scientific Center
of the Russian Academy of Sciences.
‡
For the details of electrochemical studies, see Online Supplementary
Materials.
– 389 –

Mendeleev Commun., 2019, 29, 388–390
15 L. M. Tunstad, J. A. Tucker, E. Dalcanale, J. Weiser, J. A. Bryant,
Online Supplementary Materials
J. C. Sherman, R. C. Helgeson, C. B. Knobler and D. J. Cram, J. Org.
Chem., 1989, 54, 1305.
Supplementary data associated with this article can be found
in the online version at doi: 10.1016/j.mencom.2019.07.009.
16 A. G. S. Högberg, J. Org. Chem., 1980, 45, 4498.
17 J. Kaminský, H. Dvorˇáková, J. Štursa and J. Moravcová, Collect. Czech.
References
Chem. Commun., 2011, 76, 1199.
1 I. R. Knyazeva, A. R. Burilov, M. A. Pudovik and W. D. Habicher, Russ.
Chem. Rev., 2013, 82, 150.
2 V. K. Jain and P. H. Kanaiya, Russ. Chem. Rev., 2011, 80, 75 (Usp.
Khim., 2011, 80, 77).
18 S. N. Podyachev, B. M. Gabidullin, V. V. Syakaev, S. N. Sudakova,
A. T. Gubaidullin, W. D. Habicher and A. I. Konovalov, J. Mol. Struct.,
2011, 1001, 125.
19 C. J. Curtis, A. Miedaner, R. Ciancanelli, W. W. Ellis, B. C. Noll,
M. Rakowski DuBois and D. L. DuBois, Inorg. Chem., 2003, 42, 216.
20 A. D.Wilson, R. H. Newell, M. J. McNevin, J.T. Muckerman, M. Rakowski
DuBois and D. L. DuBois, J. Am. Chem. Soc., 2006, 128, 358.
21 M. Rakowski DuBois and D. L. DuBois, Chem. Soc. Rev., 2009, 38, 62.
22 M. Rakowski Dubois and D. L. Dubois, Acc. Chem. Res., 2009, 42,
1974.
3 I. S. Antipin, E. Kh. Kazakova, W. D. Habicher and A. I. Konovalov,
Russ. Chem. Rev., 1998, 67, 905 (Usp. Khim., 1998, 67, 995).
4 I. R. Knyazeva,V. I. Sokolova, M. Gruner, W. D. Habicher, J. K.Voronina,
A. R. Burilov and M. A. Pudovik, J. Incl. Phenom. Macrocycl. Chem.,
2013, 76, 231.
5 I. R. Knyazeva, V. I. Sokolova, M. Gruner, W. D. Habicher, V. V. Syakaev,
V.V. Khrizanforova, B. M. Gabidullin,A. T. Gubaidullin,Yu. H. Budnikova,
A. R. Burilov and M. A. Pudovik, Tetrahedron Lett., 2013, 54, 3538.
6 I. R. Knyazeva, V. I. Matveeva, V. V. Syakaev, B. M. Gabidullin, A. T.
Gubaidullin, M. Gruner, W. D. Habicher, A. R. Burilov and M. A. Pudovik,
Tetrahedron Lett., 2014, 55, 7209.
7 I. R. Knyazeva, V. I. Matveeva, W. D. Habicher, V. V. Syakaev, B. M.
Gabidullin,A. T. Gubaidullin,A. R. Burilov and M.A. Pudovik, Mendeleev
Commun., 2017, 27, 287.
8 V. V. Khrizanforova, I. R. Knyazeva, V. I. Matveeva Sokolova, I. R.
Nizameev, T.V. Gryaznova, M. K. Kadirov,A. R. Burilov, O. G. Sinyashin
and Yu. H. Budnikova, Electrocatalysis, 2015, 6, 357.
9 M. K. Kadirov, I. R. Knyazeva, I. R. Nizameev, R. A. Safiullin, V. I.
Matveeva, K. V. Kholin, V. V. Khrizanforova, T. I. Ismaev, A. R. Burilov,
Yu. H. Budnikova and O. G. Sinyashin, Dalton Trans., 2016, 45, 16157.
10 V. V. Khrizanforova, I. R. Knyazeva, I. R. Nizamiev, T. V. Gryaznova,
V. I. Sokolova, S. A. Krasnov, M. K. Kadirov, A. R. Burilov, Yu. G.
Budnikova and O. G. Sinyashin, Russ. J. Gen. Chem., 2013, 83, 663
(Zh. Obshch. Khim., 2013, 83, 575).
23 S. Chen, M.-H. Ho, R. M. Bullock, D. L. DuBois, M. Dupuis, R. Rousseau
and S. Raugei, ACS Catal., 2014, 4, 229.
24 M. L. Helm, M. P. Stewart, R. M. Bullock, M. Rakowski DuBois and
D. L. DuBois, Science, 2011, 333, 863.
25 J. Hou, M. Fang,A. J. P. Cardenas, W. J. Shaw, M. L. Helm, R. M. Bullock,
J. A. S. Roberts and M. O’Hagan, Energy Environ. Sci., 2014, 7, 4013.
26 A. M.Appel, D. H. Pool, M. O’Hagan, W. J. Shaw, J.Y.Yang, M. Rakowski
DuBois, D. L. DuBois and R. M. Bullock, ACS Catal., 2011, 1, 777.
27 S. E. Smith, J.Y.Yang, D. L. DuBois and R. M. Bullock, Angew. Chem.,
Int. Ed., 2012, 51, 3152.
28 U. J. Kilgore, J. A. S. Roberts, D. H. Pool, A. M. Appel, M. P. Stewart,
M. Rakowski DuBois, W. G. Dougherty, W. S. Kassel, R. M. Bullock
and D. L. DuBois, J. Am. Chem. Soc., 2011, 133, 5861.
29 A. Dutta, S. Lense, J. Hou, M. H. Engelhard, J. A. S. Roberts and
W. J. Shaw, J. Am. Chem. Soc., 2013, 135, 18490.
30 A. Dutta, J. A. S. Roberts and W. J. Shaw, Angew. Chem., Int. Ed., 2014,
53, 6487.
31 C. Costentin and J.-M. Savéant, ChemElectroChem, 2014, 1, 1226.
32 S. Wiese, U. J. Kligore, M.-H. Ho, S. Raugei, D. L. DuBois, R. M. Bullock
and M. L. Helm, ACS Catal., 2013, 3, 2527.
11 I. R. Knyazeva, V. I. Matveeva, V. V. Khrizanforova, Yu. H. Budnikova
and A. R. Burilov, Mendeleev Commun., 2018, 28, 515.
12 I. R. Knyazeva, D. K.Abdrafikova, K. M. Mukhamedyanova,V.V. Syakaev,
B. M. Gabidullin, A. T. Gubaidullin, W. D. Habicher, A. R. Burilov and
M. A. Pudovik, Mendeleev Commun., 2017, 27, 556.
33 E. S. Rountree and J. L. Dempsey, J. Am. Chem. Soc., 2015, 137, 13371.
13 V. A. Burilov, R. I. Nugmanov, R. R. Ibragimova, S. E. Solovieva and
I. S. Antipin, Mendeleev Commun., 2015, 25, 177.
14 S. Bernardi, P. Fezzardi, G. Rispoli, S. E. Sestito, F. Peri, F. Sansone and
A. Casnati, Beilstein J. Org. Chem., 2014, 10, 1672.
Received: 18th December 2018; Com. 18/5780
– 390 –