Efficient CO2 capture by ionic liquids needs a thorough understanding of underlying mechanisms of the CO2 interaction with ionic liquids, especially when it involves chemisorption. In this work we have systematically investigated the mechanism of CO2 capture by 1,3 di-substituted imidazolium acetate ionic liquids using density functional theory. Solvent effects are analyzed using QM/MM and QM/Q...

We extend the Effective Fragment Molecular Orbital (EFMO) method to the frozen domain approach where only the geometry of an active part is optimized, while the many-body polarization effects are considered for the whole system. The new approach efficiently mapped out the entire reaction path of chorismate mutase in less than four days using 80 cores on 20 nodes, where the whole system containi...

Choosing the optimal catalyst for a new transformation is challenging because the ideal molecular requirements of the catalyst for one reaction do not always simply translate to another. Large groups at the 3,3' positions of the binaphthol rings are important for efficient stereoinduction but if they are too large this can lead to unusual or poor results. By applying a quantitative steric asses...

Invariom partitioning and notation are used to estimate anisotropic hydrogen displacements for incorporation in crystallographic refinement models. Optimized structures of the generalized invariom database and their frequency computations provide the information required: frequencies are converted to internal atomic displacements and combined with the results of a TLS (translation-libration-scr...

The frozen domain effective fragment molecular orbital method is extended to allow for the treatment of a single fragment at the MP2 level of theory. The approach is applied to the conversion of chorismate to prephenate by Chorismate Mutase, where the substrate is treated at the MP2 level of theory while the rest of the system is treated at the RHF level. MP2 geometry optimization is found to l...

New enantiopure, C(2)-symmetric biphenyl-2,2'-diols based on (-)-menthone (BIMOL), (-)-verbenone (BIVOL) and (-)-carvone (BICOL and hydrogenated BIMEOL), are accessible via short, synthetic routes. All diols form intramolecular hydrogen bonds and hence can be employed as chelating ligands for catalyst design, as it demonstrated for the (-)-fenchone based BIFOL. The sense of asymmetry of the bip...

in this study, the effect of the secondary structure of the protein on the acid strength of three structures of random (r), alpha helix (α) and beta sheet (b) were investigated theoretically. these structures are related to the cationic amino acids of histidine and lysine in the polypeptide chain of eight-glycine residue. computational methods at the hf, b3lyp, x3lyp and m05-2x levels in the ga...

The temperature dependence of H-U(iso) in N-acetyl-L-4-hydroxyproline monohydrate is investigated. Imposing a constant temperature-independent multiplier of 1.2 or 1.5 for the riding hydrogen model is found to be inaccurate, and severely underestimates H-U(iso) below 100 K. Neutron diffraction data at temperatures of 9, 150, 200 and 250 K provide benchmark results for this study. X-ray diffract...