Characteristic Features of CO₂ and CO Adsorptions to Paddle-Wheel-type Porous Coordination Polymer

Abstract

Adsorptions of CO, N2, NO, and CO2 in a paddle-wheel-type porous coordination polymer (PCP) [Cu­(aip)] n (aip = 5-azidoisophthalate) were investigated with ONIOM­[MP4­(SDQ):ωB97XD] method using a model system consisting of two [Cu2(O2CC6H4-R)4] units (R = H and Me) and one [Cu2(O2CC6H4–R)4] unit, namely, dimer and monomer models. The experimental CO adsorption position was reproduced well by the present calculation with the dimer model. For adsorptions of CO, N2, NO, and CO2 in the dimer model, the position of gas molecule deviates from the normal one that is found in the monomer model and becomes more distant from the surrounding phenyl group(s) of the neighbor [Cu­(aip)] unit. For all of these gas molecules, the calculated binding energy (BE) at the deviating adsorption position is larger than that at the normal one against our expectation that the normal position is the best for the gas adsorption. The deviation of gas adsorption position arises from the interaction between the organic linker (O2CC6H4–R moiety) and gas molecule. For all cases, the exchange repulsion with the organic linker decreases to a larger extent than the attractive electrostatic and dispersion interactions decrease when going from the normal position to the deviating one. To enhance the binding energy of gas molecule, the introduction of electron-donating substituent on phenyl moiety is computationally recommended for this PCP.

Dependence of Absorption and Emission Spectra on Polymorphs of Gold(I) Isocyanide Complexes: Theoretical Study with QM/MM Approach

“…This term corresponds to the CCSD­(T) correction; the concept of this correction is the same as that employed in the ONIOM method. , The second term was evaluated at the MP2 level under the condition that the target monomer i and the surrounding molecule j were taken as QM molecule and the remaining molecules k were taken as the MM molecules. This term corresponds to the post HF correction of the two-body QM–MM interaction energy, which is similar to the pairwise correction of dispersion interaction; actually, the corrections at the MP2, MP4­(SDQ), and CCSD­(T) levels successfully improved the description of van der Waals interactions in solid systems and metal-organic frameworks, as reported recently; − considering many successful results, this type of correction is believed to be useful for correct evaluation of weak noncovalent interaction energy. The last term was evaluated at the density functional theory (DFT) level with the B3LYP functional and D3 version of Grimme dispersion correction (called “B3LYP-D3”) − under the condition that the target monomer i and the surrounding molecules j and j ′ were taken as QM molecule and the remaining molecules k were taken as the MM molecules.…”

Phase Transitions in Metal–Organic Frameworks Directly Monitored through In Situ Variable Temperature Liquid-Cell Transmission Electron Microscopy and In Situ X-ray Diffraction

“…Metal–organic frameworks (MOFs), synthesized from metal ions/clusters and multitopic organic linkers, have attracted significant attention due to their exceptional internal surface area, crystallinity, and tunability. − These advantageous properties have been utilized for the design of functional materials including, but not limited to, adsorbents, − sensors, , catalysts and catalyst supports, − and drug carriers. , Among previously reported MOF families, Zr 6 -based MOFs, constructed from [Zr 6 (μ-O) 4 (μ-OH) 4 ] 12+ clusters and multitopic carboxylate-based organic linkers, exhibit remarkable structural versatility and superior stability under harsh conditions. − In particular, the coordination between tetratopic linkages and Zr 6 clusters has led to MOFs with various topologies and pore structures. Isolating pure phase MOFs over mixed products within this aforementioned family is highly dependent on the empirical manipulation of synthetic factors such as linker/node ratios, temperatures, concentrations, and modulator identity. ,− Indeed, 10 different topologies have been reported from tetratopic organic linkers coordinated with Zr 6 clusters including ftw, ,− csq, ,,, she, shp, scu, , flu, − ith, sqc, lvt, and stp …”

Generalized Kohn‐Sham energy decomposition analysis and its applications

“…Metal‐ligand interactions play important roles in nanocrystals, molecular recognition, drug design, metalloprotein chemistry, and so on. Both GKS‐EDA and LMO‐EDA have been employed in the interpretations of various metal‐ligand interactions, which are not trivial tasks due to the inherent complexity of the arrangement of electrons in d‐ and f‐metal‐atom orbitals coupled with the various ligands.…”

“…In order to gain insights into the adsorption of small molecules by paddle‐wheel‐type porous coordination polymers (PCP), Zheng et al explored the adsorption of CO, N 2 , NO, and CO 2 with a model molecule containing a copper cation . There are several adsorption positions in the copper complexes.…”