Ab initio calculation of the dipole moment function of hydrogen iodide

SCEP/CEPA and MC SCF potential energy and dipole moment functions for hydrogen iodide have been calculated. Spectroscopic constants and vibrational dipole matrix elements obtained from the CEPA functions are in good agreement with experimental data. In contrast to previous results for hydrogen fluoride, the MC SCF dipole moment function is less accurate than the CEPA function.     

Performance of G-Oil Well cement exposed to elevated hydrothermal curing conditions

G-Oil Well cement was modified by blending it with blast furnace slag and silica fume at various ratios. The hydration was carried out under the hydrothermal conditions (200 °C and 1.2 MPa) up to 7 days. TG and DTG were performed on cured pastes to identify the hydrated products, their quantity and their stability under given hydrothermal curing conditions. The microstructure of samples was observed by a scanning electron microscope. The mechanical compressive strength was determined and the pore structure was analyzed using mercury intrusion porosimeter. It was found out that the compressive strength values of blend G-Oil Well cements markedly increased with increasing blast furnace/silica ratio. The pore structure was consolidated, as demonstrated by the displacement of pore size distribution to the region of micro and nano pores.     

A Nexus between Theory and Experiment: Non‐Empirical Quantum Mechanical Computational Methodology Applied to Cucurbit[n]uril⋅Guest Binding Interactions

A training set of eleven X‐ray structures determined for biomimetic complexes between cucurbit[n]uril (CB[7 or 8]) hosts and adamantane‐/diamantane ammonium/aminium guests were studied with DFT‐D3 quantum mechanical computational methods to afford ΔG_calcd binding energies. A novel feature of this work is that the fidelity of the BLYP‐D3/def2‐TZVPP choice of DFT functional was proven by comparison with more accurate methods. For the first time, the CB[n] ? guest complex binding energy subcomponents [for example, ΔE_dispersion, ΔE_{electrostatic}, ΔG_solvation, binding entropy (?TΔS), and induced fit E_{deformation(host)}, E_{deformation(guest)}] were calculated. Only a few weeks of computation time per complex were required by using this protocol. The deformation (stiffness) and solvation properties (with emphasis on cavity desolvation) of cucurbit[n]uril (n=5, 6, 7, 8) isolated host molecules were also explored by means of the DFT‐D3 method. A high ρ²=0.84 correlation coefficient between ΔG_exptl and ΔG_calcd was achieved without any scaling of the calculated terms (at 298 K). This linear dependence was utilized for ΔG_calcd predictions of new complexes. The nature of binding, including the role of high energy water molecules, was also studied. The utility of introduction of tethered [‐(CH₂)_nNH₃]⁺ amino loops attached to N,N‐dimethyl‐adamantane‐1‐amine and N,N,N′,N′‐tetramethyl diamantane‐4,9‐diamine skeletons (both from an experimental and a theoretical perspective) is presented here as a promising tool for the achievement of new ultra‐high binding guests to CB[7] hosts. Predictions of not yet measured equilibrium constants are presented herein.     

Diradical Organic One-Dimensional Polymers Synthesized on a Metallic Surface

We report on the synthesis and characterization of atomically precise one-dimensional diradical peripentacene polymers on a Au(111) surface. By means of high-resolution scanning probe microscopy complemented by theoretical simulations, we provide evidence of their magnetic properties, which arise from the presence of two unpaired spins at their termini. Additionally, we probe a transition of their magnetic properties related to the length of the polymer. Peripentacene dimers exhibit an antiferromagnetic (S=0) singlet ground state. They are characterized by singlet–triplet spin-flip inelastic excitations with an effective exchange coupling (J_eff) of 2.5 meV, whereas trimers and longer peripentacene polymers reveal a paramagnetic nature and feature Kondo fingerprints at each terminus due to the unpaired spin. Our work provides access to the precise fabrication of polymers featuring diradical character which are potentially useful in carbon-based optoelectronics and spintronics.     

Preparation,physicochemical characterization and biological activity evaluation of some inclusion complexes containing artesunate

Journal of Thermal Analysis and Calorimetry - The use of cyclodextrins as carrier molecules is currently highly researched since they can improve not only the apparent water solubility and...