16 research outputs found
Stability and Hydrolyzation of Metal Organic Frameworks with Paddle-Wheel SBUs upon Hydration
Instability of most prototypical metal organic frameworks (MOFs) in the
presence of moisture is always a limita- tion for industrial scale development.
In this work, we examine the dissociation mechanism of microporous paddle wheel
frameworks M(bdc)(ted)0.5 [M=Cu, Zn, Ni, Co; bdc= 1,4-benzenedicarboxylate;
ted= triethylenediamine] in controlled humidity environments. Combined in-situ
IR spectroscopy, Raman, and Powder x-ray diffraction measurements show that the
stability and modification of isostructual M(bdc)(ted)0.5 compounds upon
exposure to water vapor critically depend on the central metal ion. A
hydrolysis reaction of water molecules with Cu-O-C is observed in the case of
Cu(bdc)(ted)0.5. Displacement reactions of ted linkers by water molecules are
identified with Zn(bdc)(ted)0.5 and Co(bdc)(ted)0.5. In contrast,.
Ni(bdc)(ted)0.5 is less suscept- ible to reaction with water vapors than the
other three compounds. In addition, the condensation of water vapors into the
framework is necessary to initiate the dissociation reaction. These findings,
supported by supported by first principles theoretical van der Waals density
functional (vdW-DF) calculations of overall reaction enthalpies, provide the
necessary information for de- termining operation conditions of this class of
MOFs with paddle wheel secondary building units and guidance for developing
more robust units
Crystallographic Evidence of Nitrate-p Interactions Involving the Electron-Deficient 1,3,5-Triazine Ring.
The reaction of Zn(NO3)2·6H2O or Cu(NO3)2·3H2O with the star-shaped ligand 2,4,6-tris(di-2-picolylamino)[1,3,5]triazine (dipicatriz) in acetonitrile results in the formation of the mono- or trinuclear coordination compounds [Zn(dipicatriz)(NO3)2] (1), [Zn3(dipicatriz)(NO3)6](CH3CN)3 (2), and [Cu3(dipicatriz)(NO3)2(H2O)6](NO3)4 (3), depending on the metal-to-ligand ratios used during the crystallization process. Their crystal structures exhibit unique supramolecular interactions. Compounds 1 and 2 show anion−π interactions between coordinated nitrate ions and the s-triazine ring. Compound 3 exhibits remarkable interactions between two noncoordinated nitrate anions and the two faces of the electron-deficient heteroaromatic ring, corroborating earlier theoretical investigations in this area. New theoretical investigations have been carried out on nitrate−π interactions, taking into account the particular position of the anion toward the aromatic ring observed in the crystal structures
The square-planar cytotoxic [cUii(PYRIMOL)cL] complex acts as an efficient DNA cleaver without reductant
Metals in Catalysis, Biomimetics & Inorganic Material