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148 Chapter 6
coordinating anion), facilitates to decrease the amount of coordinated counter-ions in the
framework of Ru II,III -BTC. Additionally, solvent exchange procedure is another way to
remove residual AcO(H), which is occluded within the framework’s pores or strongly
coordinated to the Ru-sites. Furthermore, the usage of the mono-valence Ru II,II -SBU
([Ru2 II,II (OOCCH3)4]) without any counter-ions has turned to be an optimized way to
prepare highly porous Ru II,II -BTC MOF featuring more accessible Ru-CUSs in comparison
with its mixed-valence Ru II,III -BTC variant.
Secondly, modification of the metal PWs in [M3(BTC)2Yy]n has been accomplished by inframework
incorporation of a scope of di-topic isophthalate (ip) defect generating linkers
DLs (5-X-ip, X = OH, H, NH2 or Br). Remarkably, two kinds of structural defects have been
found in the obtained crystalline and isostructural DEMOFs. One type (A) represents
modified PW nodes featuring reduced metal sites, while the other one (type B) is
associated with the missing PW nodes. In fact, the abundances of these two defect types
depend on the choice of the functional group X in the DLs, doping level of DL as well as the
chosen MOF matrix (i.e., Cu-BTC or Ru-BTC). Moreover, the defects of type A and B in Ru-
DEMOFs seem to play a key role in sorption of small molecules (i.e., CO2, CO, H2) and
catalytic activity (i.e., in ethylene dimerization and Paal-Knorr reaction). Thus,
investigations performed on the Ru-DEMOF and Cu-DEMOF solid solutions have shown
rather a complex picture. Still, the studies on the defects characterization have pave up
the way to more deep understanding of the nature of created defects and defects
engineering in MOFs in general.
Apart from the mixed-linker solid solution approach, mixing of distinct metal-ions via onepot
synthesis has also been utilized to successfully obtain Pd-doped solids Pd@[Cu3-
xPdx(BTC)2]n. To note, simultaneously structural incorporation of palladium within Pd-Pd
and/or Pd-Cu PWs as framework-nodes and Pd nanoparticles (NPs) dispersion has been
achieved for the first time. Interestingly, employing prepared Pd-doped Cu/Pd-BTC as
catalysts revealed their enhanced activity (in comparison with the intact Cu-BTC), namely
in aqueous-phase hydrogenation of p-nitrophenol (PNP) to p-aminophenol (PAP) using
NaBH4 as a hydrogen source. Furthermore, the stability and heterogeneous nature of the
catalysts have been confirmed.
All in all, the studies presented in this dissertation provide a deep insight into the
formation and structure of the complex Ru-BTC. Moreover, creation of various types of
structural defects has been gained and analyzed in its defects-engineered variants (Ru-