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72 Chapter 4
Figure 4.11. IR spectra of the prepared Ru-DEMOFs 1a-1d (with 5-OH-ip DL), 2a-2d (with ip DL),
3a-3d (with 5-NH 2 -ip DL), 4a-4c (with 5-Br-ip DL) in comparison with the parent Ru-MOF and
the corresponding DL used in the synthesis, respectively. The vertical dash lines in Figure 4.11.3
indicate position of the vibrations of N-H and C-N bonds.
Here it should be pointed out that in all 1 H-NMR spectra of the digested Ru-DEMOF
samples the resonance at ca. 1.91 ppm, originated from the –CH3 groups of acetate, has
been detected. This is in line with our previous investigations on the parent single-linker
Ru-MOFs obtained from various Ru-precursors and the Ru-DEMOFs with pydc DL, where
the same resonance due to acetate in the digested samples with the molar ratio of
n(AcO):n(BTC) in the range from 0.7 to1.8 was always observed as well. [138, 208] . We
anticipate three main origins of the presence of acetate in the discussed Ru-MOFs:
i) it may act as a counter-ion to compensate the overall charge of the framework (Figure
4.12a);