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Table 1. High resolution ESI-TOF MS data in the positive ion mode for the products of carbohydrazide exchange
reactions, products appeared as (M+H + , path a) and (M+Na + , path b) ions
Entry Measured m/z Molecular Formula Theoretical m/z Error
[ppm]
5 a,b 761.2334 a [M+H] + C 38 H 32 N 8 O 10 761.2314 a ˗2.6
783.2159 b [M+Na] + 783.2134 b ˗3.2
6 a,b 911.3277 a [M+H] + C 50 H 42 N 10 O 8 911.3260 a ˗1.9
933.3104 b [M+Na] + 933.3079 b ˗2.6
7 a,b 897.3522 a [M+H] + C 48 H 48 N 8 O 10 897.3566 a 4.9
919.3364 b [M+Na] + 919.3386 b 2.3
8 a,b 829.2949 a [M+H] + C 43 H 40 N 8 O 10 829.2940 a ˗1.1
851.2767 b [M+Na] + 851.2760 b ˗0.9
9 a,b 836.2812 a [M+H] + C 44 H 37 N 9 O 9 836.2787 a ˗3.0
858.2633 b [M+Na] + 858.2606 b ˗3.1
10 a,b 904.3423 a [M+H] + C 49 H 45 N 9 O 9 904.3413 a ˗1.1
926.3198 b [M+Na] + 926.3232 b 3.7
11 a,b 972.4040 a [M+H] + C 54 H 53 N 9 O 9 972.4039 a ˗0.1
994.3830 b [M+Na] + 994.3858 b 2.8
12 a,b 979.3886 a [M+H] + C 55 H 50 N 10 O 8 979.3886 a 0.0
1001.3740 b [M+Na] + 1001.3705 b ˗3.5
a Refluxing macrocycles 5-7, spectrum recorded after 8 days in the positive ion mode. b Refluxing building block
precursors 1-4, spectrum recorded after 8 days in the positive ion mode.
After 144 h of refluxing tetra-carbohydrazide cyclophanes 5-7 in a mixture of DMF/MeOH and
in the presence of 5 µL of AcOH, the reaction did not reach the equilibrium point. Addition of an
excess of AcOH (45 µL) was vital to facilitate the exchange process and to drive the reaction to
equilibration. In the final equilibrium composition, the molecular ions of macrocycles 5 and 8-10
possess high peak intensities in comparison with those corresponding to macrocycles 6, 7, 11 and
12. The peak intensities for all macrocycles obtained via path (a) remain steady over the course
of the reaction and did not change by prolonged refluxing. This suggested that equilibration point
can be easily reached only after 48 h of refluxing via path (a). Interestingly, a total of 11
different reaction intermediates were detected after 2 h of refluxing tetra-carbohydrazide
cyclophane macrocycles 5-7 and their precursors 1-4.
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