The reference electrophilicity and nucleophilicity scales established at the B3LYP/6-31G(d) level are herein extended by least squares regressions to most common DFT computational methods used in theoretical organic chemistry studies, including B3LYP, MPWB1K, M062-X, ωB97x-D, combination with basis sets of type 6-31G 6-311G different degrees polarization diffuse functions. Excellent linear corr...

The structures, interaction energies, vibrational analysis, and electronic properties for different urea-hydrogen peroxide (UHP) 1:1 complexes have been studied. Density functional theory (DFT) using the B3LYP hybrid exchange-correlation functional was employed to characterize five new cyclic structures in addition to the experimental one. The basis sets used were Dunning’s correlation consiste...

The MM3 force field has been extended to deal with the lithium amide molecules that are widely used as efficient catalysts for stereoselective asymmetric synthesis. The MM3 force field parameters have been determined on the basis of the ab initio MP2/6-31G* and/or DFT (B3LYP/6-31G*, B3-PW91/6-31G*) geometry optimization calculations. To evaluate the electronic interactions specific to the lithi...

O perfil de excitação Raman do anion esquarato, C 4 O 4 -2 , foi calculado por métodos ab initio no nível de teoria Hartree-Fock utilizando a Teoria de Resposta Linear (TRL) para seis frequências de excitação: 632,5, 514,5, 488,0, 457,9, 363,8 e 337,1 nm. Um total de cinco conjuntos de funções de base (6-31G*, 6-31+G*, cc-pVDZ, aug-cc-pVDZ e bases de Sadlej) foi investigado visando comparar o d...

The cyclizations of two structurally similar 2-oxo-5-hexenyl-type radicals have been investigated by ab initio and density functional (UB3LYP/6-31+G**//UHF/6-31G* and UB3LYP/6-31G*//UB3LYP/6-31G*) calculations. The origin of apparently contradictory reports of 6-endo and 5-exo cyclizations is determined. Kinetic control favors 6-endo cyclization, while thermodynamic control gives 5-exo cyclizat...

A rosane type diterpenoid has been isolated from the ethyl acetate soluble fraction of Stachys parviflora. The structure elucidation was based primarily on 1Dand 2D-NMR techniques including correlation spectroscopy (COSY), heteronuclear multiple quantum coherence (HMQC), heteronuclear multiple bond correlation (HMBC), and nuclear Overhauser effect spectroscopy (NOESY). Density functional theory...

using different DFT methods including B3LYP/6-31G(d), VWN/6-31G(d), PBE/TZP and PBE/6-31G(d) shows that, contrary to C60 , which prefers D5d symmetry, the ground state of B80 + adopts S6 point group symmetry. A D3d structure is identified as a saddle point among the S6 minima of B80 . The distortion of D3d to S6 in B80 + is attributed to a superposition of Jahn–Teller and pseudo-Jahn–Teller eff...

In this study, four different levels, B3LYP/6-31G(d,p), RM062X/6-31G(d,p), B3LYP/6-311++G(d,p) and HSEH1PBE/6-31G(d,p) of the DFT quantum chemical calculation method have been applied to molecular structure Cs-C60Cl6 molecule as a halogenated fullerene. Additionally, pure C60 fullerene was presented complementary supportive work. Furthermore, simulated FT-IR, Raman UV-Vis (in cyclohexane solven...

Objective: To evaluate the efficacy of pre-cooling and use higher gauged needles in reducing pain during local anesthetic infiltration. Material Methods: We conducted a split-mouth randomized controlled trial among 70 patients who require bilateral maxillary (LA) injections for dental treatment. After applying topical anesthetic, each participant received four injections, two on buccal palatal ...