Ruthenium Metal-Organic Frameworks with Different Defect Types: Influence on Porosity, Sorption, and Catalytic Properties.

By employing the mixed-component, solid-solution approach, various functionalized ditopic isophthalate (ip) defect-generating linkers denoted 5-X-ipH2 , where X=OH (1), H (2), NH2 (3), Br (4), were introduced into the mixed-valent ruthenium analogue of [Cu3 (btc)2 ]n (HKUST-1, btc=benzene-1,3,5-tricarboxylate) to yield Ru-DEMOFs (defect-engineered metal-organic frameworks) of the general empirical formula [Ru3 (btc)2-x (5-X-ip)x Yy ]n . Framework incorporation of 5-X-ip was confirmed by powder XRD, FTIR spectroscopy, ultrahigh-vacuum IR spectroscopy, thermogravimetric analysis, (1) H NMR spectroscopy, N2 sorption, and X-ray absorption near edge structure. Interestingly, Ru-DEMOF 1 c with 32 % framework incorporation of 5-OH-ip shows the highest BET surface area (≈1300 m(2) g(-1) , N2 adsorption, 77 K) among all materials (including the parent framework [Ru3 (btc)2 Yy ]n ). The characterization data are consistent with two kinds of structural defects induced by framework incorporation of 5-X-ip: modified paddlewheel nodes featuring reduced ruthenium sites (Ru(δ+) , 0<δ<2, type A) and missing nodes leading to enhanced porosity (type B). Their relative abundances depend on the choice of the functional group X in the defect linkers. Defects A and B also appeared to play a key role in sorption of small molecules (i.e., CO2 , CO, H2 ) and the catalytic properties of the materials (i.e., ethylene dimerization and the Paal-Knorr reaction).

Simultaneous introduction of various palladium active sites into MOF via one-pot synthesis: Pd@[Cu3-xPdx(BTC)2]n.

Simultaneous incorporation of palladium within Pd-Pd and/or Pd-Cu paddlewheels as framework-nodes and Pd nanoparticle (NP) dispersion into MOF have been achieved for the first time via one-pot synthesis. In particular, the framework substitution of Cu(2+) by Pd(2+) as well as the pore loading with PdNPs have been confirmed and characterized by XPS. The obtained solids featuring such multiple Pd-sites show enhanced catalytic activity in the aqueous-phase hydrogenation of p-nitrophenol (PNP) with NaBH4 to p-aminophenol (PAP).