Authors:Sahra C. Lemos, Silmar J. S. Franchi, Adelino V. G. Netto, Antonio E. Mauro, Oswaldo Treu-Filho, Regina C. G. Frem, Eduardo Tonon de Almeida, and Cláudia Torres
synthesis, characterization, DFT calculations, and thermal studies on compounds 1 – 4 (Scheme 1 ) by means of thermogravimetry (TG) and differential thermal analysis (DTA).
Structural representation of the
Authors:Abolfazl Shiroudi, Ehsan Zahedi, and Reza Zabihi
with nucleus independent chemical shift (NICS). Density functional theory (DFT) has been found to be successful for determining activation barriers, molecular energies, molecular geometries, electronic and magnetic properties [ 5 – 11 ]. Also, NBO
Authors:Hermi F. Brito, Jukka Hassinen, Jorma Hölsä, Högne Jungner, Taneli Laamanen, Mika Lastusaari, Marja Malkamäki, Janne Niittykoski, Pavel Novák, and Lucas C. V. Rodrigues
combination of experimental TL data and theoretical DFT (Density Fuctional Theory) calculations. The aim was to gain more information on which kind species act as the energy reservoirs in these materials.
Authors:Takayoshi Kimura, Takashi Yukiyama, and Masao Fujisawa
interaction energies of non-polar group effect on inclusion for α-CD and aliphatic nitriles in the gas phase and aqueous solution, DFT calculations were performed.
Aliphatic nitriles (H
taking place in the two-phase water-nitrobenzene system (A− = picrate, 1 = dibenzo-21-crown-7; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log Kex (1·Cs+, A−) = 4.4 ± 0.1. Further, the stability constant of the 1·Cs+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log βnb (1·Cs+) = 6.3 ± 0.1. Finally, by using quantum mechanical DFT calculations, the most probable structure of the resulting cationic
complex species 1·Cs+ was solved.
Authors:E. Makrlík, P. Toman, P. Vaňura, P. Selucký, and R. Rathore
From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Cs+(aq) + A−(aq) + 1(nb) ⇆ 1·Cs+(nb) + A− (nb) taking part in the two-phase water–nitrobenzene system (A− = picrate, 1 = hexaarylbenzene-based receptor; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log Kex (1·Cs+, A−) = 2.8 ± 0.1. Further, the stability constant of the hexaarylbenzene-based receptor·Cs+ complex (abbrev. 1·Cs+) in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log βnb (1·Cs+) = 4.7 ± 0.1. By using quantum mechanical DFT calculations, the most probable structure of the 1·Cs+ complex species was solved. In this complex having C3 symmetry, the cation Cs+ synergistically interacts with the polar ethereal oxygen fence and with the central hydrophobic benzene bottom via cation–π
interaction. Finally, the calculated binding energy of the resulting complex 1·Cs+ is −220.0 kJ/mol, confirming relatively high stability of the considered cationic complex species.
Authors:L. Cavallo, J. Ducéré, Rosalisa Fedele, A. Melchior, Maria Mimmi, G. Morini, F. Piemontesi, and Marilena Tolazzi
A calorimetric investigation on the reactions of TiCl4 with phthalates in 1,1,2,2-tetrachloroethane (TCE) is presented in order to better understand the complex interactions present
in Ziegler-Natta catalytic systems. The Lewis bases diethyl isophthalate (L1), diethyl terephthalate (L2) and the ortho-isomer diethylphthalate (L3), have been chosen to study how the substituent positions could influence the energy and the stoichiometry of the complexation
FTIR spectroscopy was used to obtain information on the coordination mode of the ligands and diffusion measurements by NMR
was carried out to verify the presence of oligo-or polymeric species. Experimental results were compared with theoretical
calculations based on Density Functional Theory (DFT).
Authors:Johannes J. C. Erasmus, Marrigje M. Conradie, and Jeanet Conradie
Density functional theory (DFT) calculations were carried out using the Amsterdam density functional (ADF) 2009 programme [ 27 – 29 ] with the generalized gradient approximation functional PW91 (Perdew–Wang, 1991) [ 30 ]. The
calculations indicate a strong negative effect of Pb atoms on the strength of the C 2 H 2 adsorption on the alloy. Very recently, a periodic slab density functional theory (DFT) study has been reported by García-Mota et al. [ 42 ] and it has provided the
isolated and deposited on a carbon support. The interaction between H 2 and the dimers is investigated by means of a simple theoretical approach based on density functional theory (DFT) combined with relatively modest basis sets. Our work addresses the