10.1002/chem.201704948
Chemistry - A European Journal
COMMUNICATION
substantial influence on its binding affinity. Stability of the
BU3∙S2O8 complex is higher by more than one order of
demand in water represents the first example of such a system,
which could be used in many applications, including radical
polymerization or chemical footprinting of proteins.[19,41,42] In
addition, the complex between the BU3 macrocycle and
peroxodisulfate with submicromolar stability in water is the most
stable assembly ever reported for inorganic dianionic guests and
artificial receptors in this medium.
2−
magnitude when compared with that of the parent carboxyalkyl
derivative. Such differences in the complex stabilities can be one
2−
of the reasons why the oxidation ability of S2O8 is suppressed
in the presence of BU3 and not BU1.
Table 1. Yields of iodide released and Fe2+ oxidized upon irradiation of
argon-saturated solutions of pHP1 and pHP2.
Conflict of interest
conversion [%][a]
I− released [%][a]
Fe2+ oxidized [%][b]
The authors declare no conflict of interest.
pHP1
pHP2
100
100
>91
>91
79[c]
82[d]
Acknowledgements
[a] Solutions of BU3 (5.1 × 10−4 M) and pHP1 or pHP2 (5.6 × 10−4 M, 1.1
equiv.) in a D2O/CD3CN (1 : 1) mixture irradiated for 10 minutes using a
1000-W Xe lamp. The reaction conversion (the consumption of pHP
derivatives) and the yields of iodide released as a complex with BU3 were
estimated using 1H-NMR. [b] The concentrations of Fe2+ ions was
determined in the presence of 1,10-phenanthroline using absorption
spectroscopy. Solutions of either [c] pHP1 or [d] pHP2 in a H2O/CH3CN (99 :
1) mixture irradiated in the presence of BU3, Na2S2O8 and FeSO4 (the molar
ratios: 1.1 : 1 : 1 : 2).
This work was supported by the Czech Science Foundation
(V.S.: 13-15576S, P.K.: GA13-25775S) and the Ministry of
Education, Youth and Sports of the Czech Republic (LQ1601,
LO1214, and LM2015051). We acknowledge the CF X-ray
diffraction and Bio-SAXS supported by the CIISB research
infrastructure (LM2015043 funded by MEYS CR). The authors
thank to Peter Štacko for fruitful discussions and help with the
photochemical experiments.
Keywords: bambusurils • anion recognition • macrocycles •
supramolecular chemistry • self-assembly
Table 2. Yields of iodide released and Fe2+ oxidized upon irradiation of argon-
saturated solutions of pHP1 and pHP2.
Notes
−1
host
guest
Ka/M
ΔH°/kJ mol−1
TΔS°/kJ mol−1
(CCDC 1566757).
BU1
K2S2O8
TMAI
(3.1 ± 0.1) × 105
(1.8 ± 0.1) × 106
(8.3 ± 0.1) × 106
(1.3 ± 0.1) × 107
(1.3 ± 0.1) × 107
−96.4 ± 5.5
−80.5 ± 1.8
−95.5 ± 2.8
−69.0 ± 1.6
−66.1 ± 2.1
−64.6
−44.2
−55.3
−27.8
−24.9
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