Multifunctional, Defect‐Engineered Metal–Organic Frameworks with Ruthenium Centers: Sorption and Catalytic Properties

Origin of highly active metal–organic framework catalysts: defects? Defects!

“…31 Defect engineering by PyDC doping was also recently applied to the Ru 2+ /Ru 3+ analogue of HKUST-1. 84 The substitution by PyDC yields materials with more strongly reduced Ru x+ species (x ≤ 2) as a result of partial reduction of the metal node upon increasing the carboxylate vacancies. Here also, MOFs with reduced metals demonstrated up to four times higher activity in the hydrogenation of 1-octene.…”

Defects and Disorder in MOFs

“…On the other hand, one of the most common strategies in the creation of defects is direct copolymerization of the so-called defect linker (DL) along with the basic linker L of a given MOF or a combination of distinct metal ions -a solid solution (or linker-fragmentation) approach [13,15,[55][56][57][58]61] (Figures 26.1 and 26.2). From a broader perspective, an oligotopic molecule of similar or almost identical topology and coordination chemistry as the parent linker L but lacking some of the connector sites or having one or more of these exchanged by weaker interacting connectors could act as DL.…”

“…Creation of linker vacancies is realized via removal of the entire linker molecule or introduction of DL (or modulator) where no "compensation" by -O, -Hal, or -OH ligation takes place. Considering the situations of the loss of negative charge, discrepancies between DL and L charges, and the fact that many of MOFs are constructed from the redox-active metals (in rare cases also from the redox-active linkers), charge compensation could be also realized via partial reduction/oxidation of the framework's component(s) [54,56,57]. Such situation would prevent full metal coordination, leading to mCUSs generation.…”

“…Such defect clustering might be of crucial importance to affect mass transport, reduce framework's density, and trigger extraordinary electronic, magnetic, optical, and mechanical properties (e.g., negative thermal expansion, crystalline ↔ amorphous switching). Moreover, controlled introduction and correlation of defects would enable a design of complex active sites (e.g., cooperatively arranged mCUSs) [57,59] required for specific catalytical reactions, for example.…”

The Effects of Alkaline‐Earth Counterions on the Architectures, Band‐Gap Energies, and Proton Transfer of Triazole‐Based Coordination Polymers

“…[32] This field of research has gained attention owing to the potential tuning of the optical properties of these hybrid structures through modification of the SBU or the organic linker. [33][34][35][36][37][38][39][40] These structures offer opportunities for variation of the architecture as well as control over the dimensionality through the judicious choice of the SBU and organic linker, which may in turn effect the band-gap energy. [33,36,[41][42][43][44] Recently, Lin et al showed that the size of the metal cluster and linker have a pronounced effect on the band-gap energy, [41] and Hendon et al have shown that ligand functionalization can be used to engineer and control the optical response of MOFs.…”