The syntheses of new tetraaza macrocyclic compounds of variable ring sizes by non-template methods and their characterization with the help of elemental analysis and spectroscopic techniques (FT-IR, 1 H-NMR, and 13 C-NMR) have been reported in detail. The vibrational frequencies determined experimentally are compared with those obtained theoretically from density functional theory (DFT) and Har...

Density functional theory calculations with the B3LYP functional were performed for the title ring-opening reaction to understand the intrinsic activating and directing effects of the N-substituents, as well as the electron donating effect of the para-substituted (Y = Cl, H, Me) phenyl group at the more hindered benzylic C2 atom. The N-tosyl group (i.e., N-Tos) or the N-(2-pyridyl)sulfonyl grou...

Furylpyridines are composite molecules having two subsystems as pyridine and furan molecules connected together by a single bond. The constituting subsystems pyridine and furan molecules can rotate along the single bond linking them together. Firstly, the equilibrium geometries of furylpyridines have been obtained through geometry optimization using density functional theory at the B3LYP/ 6-311...

We carried out a molecular modeling study of an important reaction in the combustion of nitrogen-containing chars, the evolution of nitric oxide, (CNO)!NO+(C*). Density functional theory at the B3LYP level was used to provide potential energy surface information and transition state theory was used to provide temperature dependant rate constants. Desorption of NO from nitrogen-containing carbon...

The infrared (IR) and Raman spectra of triphenylene with intensities were calculated using both density functional theory (DFT, B3LYP method) and Moller-Plesset perturbation method of second order (MP2) with ccpVDZ basis set. Spectra were compared with experimentally measured; the agreement between the observed and calculated spectra is good in case of IR spectroscopy, MP2 simulated spectra wer...

Quantum mechanical calculations of energies, geometries and vibrational wavenumbers of 2-fluoro-5-methylbenzonitrile (2F5MBN) have been carried out by using density functional theory (DFT/B3LYP) method with 6-311++G(d,p), cc-pvdz, Aug-cc-pvdz as basis sets. The optimized geometrical parameters obtained by DFT calculations are found to be in good agreement with experimental X-ray data. The best ...

3d-Metal mononitrides are studied using the density functional theory method. The lowest spin state for these dimers is obtained using the B3LYP hybrid functional with the 6-311 G* basis set. The equilibrium geometries, vibrational frequencies, binding energies, Mulliken, and natural orbital population analysis charges, natural orbital electronic configuration, electron affinity, and ionization...

Karplus relationships for all 26 NMR spin-spin coupling constants (SSCCs) J of the pseudorotating tetrahydrofuran (THF) molecule were derived by expanding J as a function J(q,φ) of the puckering amplitude q and the pseudorotational phase angle φ. For this purpose, the conformational potential V(q,φ) of THF was determined at the MBPT(2)/ccpVTZ and B3LYP/6-31G(d,p) levels of theory. THF is a slig...

Multi-reference effects can be covered by density functional theory (DFT) either implicitly via the exchange-correlation functional or explicitly via the form of the Kohn-Sham wave function. With the help of the exchange hole it is shown that the self-interaction error of the exchange functional will mimic long-range electron correlation effects if restricted Kohn-Sham theory is used. Functiona...

We report an implementation for the computation of optical rotations within the Amsterdam Density Functional program package. The code is based on time-dependent density functional response theory. Optical rotations have been calculated for a test set of 36 organic molecules with various density functionals, and employing basis sets of different quality. The results obtained in this work with n...