Density functional theory investigations on binding and spectral features of complexes of ferrocenyl derivatives with cucurbit [7]uril

Harnessing desktop computers for ab initio calculation of vibrational IR/Raman spectra of large molecules

“…For this purpose, the initial geometry is taken from Ref. 28 which is further optimized at ωB97X/6-31++G** level of theory. Single point energy and spectral calculations are done at the level of theory and basis set specified in Table 1.…”

Molecular Recognition, Conformational Behavior, and Spectral Characteristics of Oxatub[4]arene Macrocycle

“…The ωB97X-D hybrid exchange correlation functional proposed by Head-Gordon and co-workers was employed in conjunction with the internally stored 6-311+G­(d,p) basis set. This level of theory is adequate for a faithful representation of underlying supramolecular interactions and describe well the electron distribution in host–guest chemistry. − The stationary point structures of the host, guest, and their complexes were confirmed to be the local minima on the multivariate potential energy surfaces from vibrational frequency calculations. The complexation of TA4 cavitands can be understood from the charge distribution within its cavity, which can be characterized in terms of the molecular electrostatic potential (MESP) topography. − To elucidate the nature and strength of underlying molecular interactions accompanying the guest encapsulation, QTAIM analyses were carried out with the help of AIMAll-2000 software. , Furthermore, the nonlocalized dispersion and repulsive nonbonded interactions can be assured employing the NCI-RDG method as a tool .…”

Cooperative Hydrogen Bonding, Molecular Electrostatic Potentials, and Spectral Characteristics of Partial Thia-Substituted Calix[4]arene Macrocycles

“…The present ab initio theoretical attempt systematically analyze the energetics accompanying the conformational changes in 2,14-dithiacalix[4]­arenes and their homooxa derivatives, which are compared with calix[4]­arene and thia derivatives. Recent works demonstrating the use of hybrid-exchange correlation functionals incorporating the long-range damped dispersion interactions proposed by Head-Gordon and co-workers have successfully been applied to describe a variety of chemical phenomena. − Taking a cue from these studies, we employ the hybrid ωB97X-D exchange correlation functional in conjunction with the 6-311++G­(d,p) basis set incorporating polarized as well as diffuse functions on all the atom centers, which are known to simulate hydrogen-bonding effects to adequately typify the noncovalent interactions . Geometry optimizations of stationary point structures exhibiting different hydrogen-bonded patterns were carried out within the framework of DFT with the use of Gaussian 09 suite of programs .…”