In this study, the optimized geometries, frequencies of the stationary point and the minimum-energy paths of C13H12F7ClN2O are calculated by using the DFT (B3LYP) methods with LANL2DZ basis sets. B3LYP/LANL2DZ calculation results indicated some selected bond length and bond angles values for the fluorous compound C13H12F7ClN2O.
How to cite this article:
Shahriar Ghammamy, Masomeh Shahsavary and Amir Lashgari, 2014. Structural Properties, Natural Bond Orbital, Density Functional Theory (DFT) and Energy Calculations for Fluorous Compound: C13H12F7ClN2O. Current Research in Chemistry, 6: 16-21.
Fluorous molecules comprise an organic domain and a highly fluorinated domain. Ideally, the organic domain controls reactivity and the fluorinated domain controls separation. Generally, >60% fluorine by weight is called a heavy fluorous compound. These materials have limited solubility in non-fluorous media, typically require perfluorinated solvents and are expensive, all of which limits practical adoption. Light fluorous compounds (<40% by weight) are miscible in organic solvents and cost less. Since, they typically will not form a separate fluorous liquid phase, light fluorous compounds are separated using a companion fluorous stationary phase.
Whereas, compounds bearing light fluorous tags are miscible in organic solvents, heavy fluorous compounds are soluble in perfluorinated solvents and form a distinct liquid phase. Fluorous stationary phases exhibit high selectivity for retention of fluorous versus non-fluorous molecules. In addition, fluorous sorbents are able to resolve fluorous molecules of differing fluorine content (Zhang, 2004a, b; Curran and Matsugi, 2005; Dandapani et al., 2005; Gladysz and Curran, 2002).
During this study, we report the optimized geometries, assignments and electronic structure calculations for the compound. The structure of the compound has been optimized by using the DFT (B3LYP) method with the LANL2DZ basis sets, using the Gaussian 98 program Frisch and Trucks (1998). The comparison between theory and experiment is made. Density functional theory methods were employed to determine the optimized structures of C13H12F7ClN2O and initial calculations were performed at the DFT level and split valence plus polarization LANL2DZ basis sets were used. Local minima were obtained by full geometrical optimization have all positive frequencies (Vrajmasu et al., 2004; Smith et al., 2005).
All computationals are carried out using Gaussian 98 program. Energy minimum molecular geometries were located by minimizing energy with respect to all geometrical coordinates without imposing any symmetrical constraints (Ghammamy et al., 2011).
RESULTS AND DISCUSSION
Molecular properties: The structures of compounds are shown in Fig. 1. All calculations were carried out using the computer program Gaussian 98. Theoretical calculation of bond length and angle for the compound was determined by optimizing the geometry (Table 1).
The NBO calculated hybridizations are presensted in Table 2. We could not compare the calculation results given in bond lengths and bond angle values with the experimental data because the crystal structure of the title compound is not available till now.
NBO study on structures: Natural charges have been computed using Natural Bond Orbital (NBO) module implemented in Gaussian 98. The NBO calculated hybridizations are significant parameters for our investigation. These quantities are derived from the NBO population analysis. The former provides an orbital picture that is closer to the classical Lewis structure. The NBO analysis involving hybridizations of selected bonds are calculated at B3LYP methods and LANL2DZ level of theory (Table 2).
These data shows the hyperconjugation of electrons between ligand atoms with central metal atom. The NBO calculated hybridization for C13H12F7ClN2O shows that all of complexes have Spx hybridization and non-planar configurations. The total hybridization of these molecules are Spx that was confirmed by structure.
|Fig. 1:||Schematic structure of the C13H12F7ClN2O|
|Table 1:||Geometrical parameters optimized for C13H12F7ClN2O, some selected bond lengths (Å) and angles (°)|
The amount of bond hybridization showed the inequality between central atoms angles, Table 2 shows distortion from octahedral and VSEPR structural and confirmed deviation from VSEPR structures. Second order perturbation theory analysis of Fock matrix in NBO basis for C13H12F7ClN2O means energy of hyperconjugative interaction (stabilization energy) Table 3.
|Table 2:||NBO calculated hybridizations for C13H12F7ClN2O acalculated at B3LYP/LANL2DZ|
|Table 3:||Second order perturbation theory analysis of Fock matrix in NBO basis for C13H12F7ClN2O|
|aEnergy difference between donor and acceptor i and j NBO orbital's, bF(i, j) is the fock matrix element between i and j NBO|
|Fig. 2:||Atomic orbital of the frontier molecular orbital for C13H12F7ClN2O B3LYP/LANL2DZ level of theory|
Frontier molecular orbital: Energy difference between HOMO and LUMO orbital is called as energy gap that is an important stability for structures. In addition, 3D plots of Highest Occupied Molecular Orbitals (HOMOs) and Lowest Unoccupied Molecular Orbitals (LUMOs) are shown in Fig. 2. The HOMO-LUMO energies were also calculated at the LANL2DZ and the values are listed in Fig. 2, respectively.
In this study, we are interested in study on fluorous compound. Organic compound was chosen for theoretical studies. In this study, the optimized geometries and frequencies of the stationary point and the minimum-energy paths are calculated by using the DFT (B3LYP) methods with LANL2DZ basis sets. B3LYP/ LANL2DZ calculation results indicated some selected bond length and bond angles values for the C13H12F7ClN2O.
The authors wish to express their warm thanks to Dr. Ghammamy for his valuable discussions and Imam Khomeini international University, for their assistance.
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