Quantum chemical and thermodynamic calculations of fulvic and humic copper complexes in reactions of malachite and azurite formation

Towards Computational Screening for New Energetic Molecules: Calculation of Heat of Formation and Determination of Bond Strengths by Local Mode Analysis

“…While the outcome showed that PM7 was the least accurate of the three ( R 2 line of best fit against experimental data = 0.986, compared to 0.999 and 0.995 for the isodesmic and atom equivalence methods, respectively), it still performs relatively well, and has the advantage of being an easily deployed method that can be used for any molecule containing atoms from H−La and Lu−Bi. Fomin et al (2017) tested the PM7 method alongside other semi-empirical methods, namely PM6, PM5, PM3, AM/1, and MNDO, for calculating ∆H f(g) for copper and alkaline Earth metal complexes. They concluded that PM6 and PM7 both perform well, reporting R 2 values of 0.961 and 0.960, respectively.…”

Enantiopurification of Mandelic Acid by Crystallization-Induced Diastereomer Transformation: An Experimental and Computational Study

“…We used the BFGS algorithm for the full relaxation (both lattice and atomic position optimizations) of the crystal structure. Using the DFT-optimized structures, we calculated the lattice energies via the semiempirical PM7 method as implemented in MOPAC v2016 which has been shown to have good performance in predicting thermodynamic properties particularly for organic systems. , To validate the calculated lattice energies, we compared the experimental melting point against the melting point computed from the lattice energy using the simple model of Salahinejad et al This model assumes a linear relationship between the ratio of enthalpy of sublimation to the melting point (Δ H sub / T m ) against the number of rotatable bonds …”

Separation of Etiracetam Enantiomers Using Enantiospecific Cocrystallization with 2-Chloromandelic Acid

“…The generated unit cells were then optimized using the semiempirical PM7 Hamiltonian with periodic boundary conditions as implemented in MOPAC v2016, 29 , 30 which has been shown to have good performance in predicting thermodynamic properties particularly for organic systems. 31 , 32 The structures of the five most stable candidates were further refined using periodic density functional theory (DFT) calculations as implemented in the CP2K package, 33 which uses a mixed Gaussian/plane-wave (GPW) basis set. The exchange and correlation energies were evaluated using the semilocal Perdew–Burke–Ernzerhof (PBE) form of the generalized gradient approximation (GGA) functional together with Grimme’s D3 van der Waals correction.…”

“…To reduce the computational cost, we constrained the search space to the most common space groups for chiral cocrystals, i.e., P 1, P -1, P2, P 21, P 21/ c , and P 212121. The generated unit cells were then optimized using the semiempirical PM7 Hamiltonian with periodic boundary conditions as implemented in MOPAC v2016, , which has been shown to have good performance in predicting thermodynamic properties particularly for organic systems. , The structures of the five most stable candidates were further refined using periodic density functional theory (DFT) calculations as implemented in the CP2K package, which uses a mixed Gaussian/plane-wave (GPW) basis set. The exchange and correlation energies were evaluated using the semilocal Perdew–Burke–Ernzerhof (PBE) form of the generalized gradient approximation (GGA) functional together with Grimme’s D3 van der Waals correction. , DZVP-MOLOPT basis sets and Goedecker–Teter–Hutter (GTH) pseudopotentials were selected in the calculations. , An energy cutoff of 500 Ry and relative energy cutoff of 80 Ry were found to be sufficient for energy convergence.…”