241 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
Geometry analysis and systematic synthesis of highly porous isoreticular frameworks with a unique topology
Porous coordination polymers are well known for their easily tailored framework structures and corresponding properties. Although systematic modulations of pore sizes of binary prototypes have gained great success, simultaneous adjustment of both pore size and shape of ternary prototypes remains unexplored, owing to the difficulty in controlling the self-assembly of multiple molecular building blocks. Here we show that simple geometry analysis can be used to estimate the influence of the linker lengths and length ratios on the synthesis/construction difficulties and framework stabilities of a highly symmetric, ternary prototype composed of a typical trinuclear metal cluster and two types of bridging carboxylate ligands. As predicted, systematic syntheses with 5×5 ligand combinations produced 13 highly porous isoreticular frameworks, which show not only systematic adjustment of pore volumes (0.49–2.04 cm3 g−1) and sizes (7.8–13.0 Å; 5.2–12.0 Å; 7.4–17.4 Å), but also anisotropic modulation of the pore shapes
CCDC 1423720: Experimental Crystal Structure Determination
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures
Dilithium cyclohexanediacetate:A layered coordination polymer with non-valent hydrophobic contacts
CCDC 1423719: Experimental Crystal Structure Determination
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures
Synthesis and characterization of chiral copper(II) coordination polymers with 4,4A '-bipyridine and lactic acid derivatives
Selective gas adsorption in microporous metal-organic frameworks incorporating urotropine basic sites: An experimental and theoretical study
Urotropine-based porous coordination polymers with free N-donors demonstrate selective adsorption towards acidic gas substrates (C2H2 or CO2) as confirmed by isotherm measurements and ab initio DFT calculations.</p
CCDC 1059061: Experimental Crystal Structure Determination
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures
- …