Self-consistent Reaction Field Method Research Articles

Applicability of self-consistent reaction field (SCRF) method to DFT estimation of hydrogen isotope separation factors in reversible processes

ABSTRACT In earlier quantum chemical calculations of isotope effects, chemical species in the liquid phase were generally treated as existing in the gas phase. In recent years, however, advances in computational programs have made it easier for the self-consistent reaction field (SCRF) method to handle chemical species in the liquid phase, and as a result, it has become easier to apply the SCRF method to isotope effect calculations. This paper concerns the scope of application of the DFT-SCRF method to reversible processes for hydrogen isotope enrichment. It is found that the applicability of the method depends on the type of the intermolecular interaction in the liquid phase and the degree of hydrogen isotope effect (separation factor) on which the process is based. When the magnitude of the isotope effect of the separation system is greater than 10–1, the simple SCRF method is fully applicable; when the magnitude is around 10–2, SCRF with a dimer model, in which the monomer is replaced by a dimer, is applicable for the analysis of the liquid phase with relatively strong intermolecular interactions. Anharmonic correction to the separation factor calculated based on harmonic frequencies may be effective to systems with the liquid phase with weak intermolecular interactions.

Interaction of Isonicotinic Acid Hydrazide with Carboxylic Acid Anhydrides

There has been presented data on the synthesis of monoamides and cyclic imides which are derivatives of isonicotinic acid hydrazide. Cyclic anhydrides of carboxylic acids (succinic, maleic and phthalic) easily react with the hydrazide of isonicotinic acid with cycle opening, forming isonicotinoylhydrazide of dicarboxylic acids, and under more severe conditions the latter are transformed into cyclic acid imides. The structures of the synthesized compounds were studied using 1H- and 13C-NMR spectroscopy, as well as data from twodimensional COSY (1H-1H) and HMQC (1H-13C) spectra. The values of chemical shifts, multiplicity and integral intensity of 1H and 13C signals in one-dimensional NMR spectra were determined. Homo- and heteronuclear interactions confirming the structure of the studied compounds were established using spectra in the COSY (1H-1H) and HMQC (1H-13C) formats. In the approximation of the density functional B3LYP with a base set of 6-31G(d), the enthalpy of the reactions ΔHr in the absence and in the presence of a solvent — isopropanol (self-consistent reaction field method) were calculated quantum-chemically

(Trifluorosilyl)methyl 2-methylacrylate: Synthesis, experimental and theoretical studies

The novel stable organosilicon compound containing pentacoordinated silicon atom, named as (trifluorosilyl)methyl 2-methylacrylate, was synthesized and fully characterized including single-crystal X-ray diffraction. The asymmetric unit of the title compound contains two independent molecules, one of which adopting the s-cis configuration and the other has the s-trans configuration with respect to the CO and CC bonds. In the crystal, conformers form cis- and trans-dimeric pairs due to tetrel-bonding interaction and hydrogen bonds CH··· F. Energetic and geometric characteristics for these dimers were calculated by DFT methods at M06-2X/6-311G(d,p) level of theory using QTAIM analysis. The calculations in the polar medium (DMSO) for two dimeric fragments of crystal packing were performed with Onsager self-consistent reaction field method.

A comprehensive theoretical analysis of Curtius rearrangement of syn-syn and syn-anti conformers of oxalyl diazide

The complete theoretical study of thermal Curtius rearrangement of syn-syn and syn-anti conformers of oxalyl diazide, in the gas phase and in solution has been established for the first time. The inexplicit solvent effect was taken into account via the self-consistent reaction field (SCRF) method. The gas and solution phases of all optimized geometries of the mentioned conformers associated with the Curtius rearrangement along the concerted and stepwise pathways were reported using the polarized continuum model and non-electrostatic terms from the SMD universal solvation model. The Curtius rearrangement of syn-syn and syn-anti conformers was taken place via concerted and stepwise pathways, respectively. The syn-syn conformer of oxalyl diazide is more stable than the syn-anti conformer in the gas phase and solution, and rearranged to syn-carbonyl azide isocyanate via an exergonic concerted mechanism with a single transition state. Nevertheless, the rearrangement of syn-anti conformer occurred through the two transition states and an intermediate, which the first and second steps are endergonic and exergonic, respectively. Theoretical results point out that the concerted pathway is predominant with 102-106 and 104-105 times faster than the stepwise mechanism in gas phase and solution, respectively. Topological analysis of the electron localization function at the B3LYP/6–311++G (2d,d,p) level of theory indicate that the catastrophe sequence 1-6-C†TSC†F C†C-0 begins with the N4–N5 bond breaking, elimination of nitrogen molecule and increasing of non-bonding monosynaptic attractor on N4 atom, and then changing of topological signature of C2–N4 bond, breaking of C1–C2 bond, and formation of pseudo-radical centers on C1 and C2 atoms. Subsequently, annihilation of pseudo-radical centers on the C1 atom, change of topological signature of C2–N4 and formation of C1–N4 bond were executed. The obtained results of ELF calculations show that the reaction takes place via a concerted mechanism but highly asynchronous process.

Biophysical study of selenocysteine and selenomethionine in the gas and solution phases

Proteins containing selenium play a variety of important roles in cellular activity. The structural and vibrational studies of d-selenocysteine and d-selenomethionine in the gas phase and in the aqueous phase are investigated. Møller-Plesset second-order (MP2) and density functional theories (DFT) were used to find the optimised structure. The basis set used is 6–311++G (d, p) for all atoms. All the structures are fully optimised, and the optimised geometries, frequencies, and energies are reported. The amino acid zwitterion forms in water were also investigated to predict the most stable form of the amino acids in solution. The effect of the solvent is simulated by using the polarizable continuum models within the self-consistent reaction field method (SCRF) at the B3LYP/6–311++G(d,p) level. It is predicted that, zwitterion is the most stable form in solution. In terms of total energy, the selenium analogue has the lowest energy, followed by the sulfur analogue.

Theoretical DFT Studies on Free Base, Cationic and Hydrochloride Species of Narcotic Tramadol Agent in Gas Phase and Aqueous Solution

Theoretical studies based on the density functional theory (DFT) have been performed to study structural and vibrational properties of the free base, cationic, and hydrochloride species of narcotic tramadol agent in the gas phase and aqueous solution. In both media, B3LYP/6-31G* calculations were used while in solution, the self-consistent reaction field (SCRF) method together with the integral equation formalism variant polarised continuum (IEFPCM) and universal solvation model density (SMD) models have been employed because these models consider the solvent effects. The vibrational studies have revealed that the species cationic is present in the solid phase because the most intense band predicted for the hydrochloride in infrared and Raman spectra is not observed in the experimental spectra. The harmonic force fields, together with the normal internal coordinates and scaling factors, have allowed the complete vibrational assignments of 126, 129, and 132 vibration modes expected for the free base, cationic, and hydrochloride species, respectively, by using the SQMFF methodology. The cationic species evidence the most negative solvation energy and higher hydration in solution in agreement with its lower stability, while the hydrochloride species is the most reactive in solution. MK charges and NBO and AIM studies support cationic species' instability due to the positive charge on N atom. Comparisons of the experimental UV spectrum of hydrochloride tramadol with the predicted for the three species suggest that the free base, cationic, and hydrochloride species can be present in solution. Comparisons of predicted infrared, Raman, 1H, and 13C NMR and electronic spectra for the free base, cationic, and hydrochloride species of tramadol with the corresponding experimental ones have evidenced reasonable correlations for the cationic species showing that this species present in the solid phase and in solution.

Study of antimicrobial and antioxidant activities of pyrrole-chalcones

The resistance of pathogenic microorganisms to accessible antibiotics, anxiolytics, sedatives, hypnotics and anti-convulsants are rapidly forming a foremost problem worldwide. The detailed spectroscopic, DFT, antimicrobial, and antioxidant analysis of synthesized pyrrole chalcone derivatives (3a, 3c, 3h, 3i, and 5a) have been performed and interpreted. Occurring of doublet in 1H NMR spectra of (3a, 3c, 3h, 3i, and 5a) compounds in the range of δ 7.656-6.960 confirms the presence of β-vinyl (=C-H) proton and another doublet at δ 7.206-6.707 confirms the presence of α-vinyl (=C-H) proton, respectively, confirming the formation of reported products. The global electrophilicity index (ω = 5.26 eV) shows that the (3g) molecule is a strong electrophile among all the studied compound. All compounds tends to the formation of pyrazoline, oxazoline heterocyclic compounds which may have considerable pharmacological activities and material applications. The solvent-induced effects on the non-linear optical properties (NLO) were studied by using self-consistent reaction field (SCRF) method. As the solvent polarity increases, the β value have been found to increases monotonically. The compound (3a, 3c, 3g, 3h, 3i, and 5a) displayed better non-linear optical (NLO) responses than the standard p-Nitro aniline (pNA) in solvent and as well as in gas phase. 3g and 3i have high NLO values even in gas phase which can be attributed to their unsymmetrical and high non-planar structure. All studied compounds (3a, 3c, 3g, 3h, 3i, and 5a) show good antifungal and antibacterial activity against A. Niger and gram-positive bacteria B. subtilis but 3g, 3h, and 3i showed more prominent activity which can be attributed to their either substituents. Compounds 3h, 3c, 3a, and 3g showed better free radical scavenging than standard BHT, whereas 3h, 3c, 3a showed better Fe2+ ion chelating activity than standard EDTA, and better Total reductive capability than standard BHA. Thus they are suitable for both material and biological applications.

Nitrogen Isotopic Reduced Partition Function Ratios of Glycine and Serine in Water.

The nitrogen isotopic reduced partition function ratio (RPFR) of glycine (Gly) and serine (Ser) in water has been evaluated by a couple of methods. The experimental fact that those amino acids are present in the zwitterionic form in water has been best reproduced when trihydrated Gly and Ser molecules were treated by the discrete microsolvation method coupled with the self-consistent reaction field (SCRF) approach. The RPFR values of Gly and Ser in water at 25 °C are evaluated as 1.11152 and 1.11070, respectively, and the equilibrium constant of the nitrogen isotope exchange reaction between the two amino acids is calculated as 1.0007 ± 0.0008 at 25 °C. Equivalent results may be obtained by the SCRF method for non- and monohydrated molecules in the zwitterionic form.

Solvent Influence on Structure and Electronic Properties of Si2Me4: A Computational Investigation Using PCM-SCRF Method

The stability of Si2Me4 molecules in C2h and D2h symmetries were studied at M062X/Def2-TZVPP level of theory. Our calculations were performed for gas and solution phases. A self-consistent reaction field (SCRF) method, utilizing the polarizable continuum model (PCM) was used, and the solvation model utilized the radii and non-electrostatic terms of the solvent model density (SMD). The solvent effect on the structural parameters and reactivity parameters (hardness, chemical potential and electrophilicity) was explored. Stability of the SiMe2 fragments were investigated in the singlet and triplet states for illustration of the Si=Si bond character. Also, energy decomposition analysis (EDA) was used for calculations of the contribution of polarized and steric energy values in the interaction energy values between SiMe2 fragments in the two studied phase.

Structural and SQMFF study of potent insecticide 4′,4′-DDT combining the FT-IR and FT-Raman spectra with DFT calculations

The experimental FT-IR and FT-Raman spectra in the solid state have been employed to vibrationally characterize the potent insecticide dichlorodiphenyltrichloroethane (4′,4′-DDT). The complete vibrational assignments of 4′,4′-DDT in gas phase and in acetone and diethyl-ether were performed combining hybrid B3LYP/6-31G* and B3LYP/6–311++G** calculations with the internal coordinates, the scaled quantum mechanical force field (SQMFF) methodology and the experimental spectra. Here, the molecular structures of 4′,4′-DDT were theoretically determined in gas phase and in acetone and diethyl-ether solutions by using those two methods. The self-consistent reaction field (SCRF) method and the integral equation formalism variant polarised continuum model (IEFPCM) model were employed to study the properties in solution while the solvation energies were predicted by using the solvation model. The B3LYP/6–311++G** calculations show higher solvation energy in the solvent with lower permittivity, diethyl-ether. A clear and direct correlation was found with both basis sets between solvation energy and dipole moment for those two solvents. NBO studies clearly show that dichlorodiphenyl groups confer to 4,4′-DDT higher stability than the trichloroethyl group due to the fact that the lone pairs of Cl21 and Cl22 atoms present the n→π* transitions while the AIM study shows the participation of trichloroethyl group in halogen bonds clearly justifying the stability of 4′,4′-DDT in the three media and with both basis sets. The MK and NPA charges evidence different behaviors in both media and with both basis sets. The frontier orbitals show that the reactivity of 4,4′-DDT strongly depends on the basis set while it is more reactive than dieldrin, hexachlorobenzene and saxitoxin but 3,3′,4,4′-tetrachloroazobenzene, 3,3′,4,4′ tetrachloroazoxybenzene, CN− and CO species present higher reactivity than 4,4′-DDT. The number of Cl atoms could justify the differences observed in the nucleophilicity indexes of 4,4′-DDT, dieldrin, hexachlorobenzene, 3,3′,4,4′-tetrachloroazobenzene and 3,3′,4,4′ tetrachloroazoxybenzene.

Structural, FT-IR, FT-Raman and ECD studies on the free base, cationic and hydrobromide species of scopolamine alkaloid

The complete vibrational assignments for the alkaloid scopolamine as free base, quaternary scopolammonium cationic and hydrobromide species were reported for first time by using the internal coordinates, the scaled quantum mechanical force field (SQMFF) procedure and the experimental FT-IR, FT-Raman spectra of hydrobromide tri-hydrate. Hybrid B3LYP/6-31G* calculations were employed to study two pairs of R and S enantiomers of free base, cationic and hydrobromide forms in gas and aqueous solution phases. The properties in solution were studied with the self-consistent reaction field (SCRF) method and the integral equation formalism variant polarised continuum model (IEFPCM) model while the solvation energies were computed by using the solvation model. The structural, electronic, topological and vibrational properties were studied only for the most stable structure of each form by using natural bond orbital (NBO) and atoms in molecules (AIM) analyses. Also, the Mulliken and Merz-Kollman (MK) charges were evaluated in both media together with the molecular electrostatic potential (MEP) in order to predict the potential nucleophilic and electrophilic reaction sites for each species. The frontier orbitals and some descriptors were investigated for those three species in order to compare with those reported for heroin, morphine, cocaine and tropane alkaloids. Here, the force fields and the complete assignments of the 123, 126 and 129 vibration normal modes expected for the free, cationic and hydrobromine anhydrate form of scopolamine alkaloid are reported. The predicted infrared, Raman and Electronic Circular Dichroism (ECD) support the presence of cationic S2 form of scopolamine in the solid state, in concordance with the corresponding experimental structure determined by X-ray diffraction. In addition, the force constants are reported for the three species of scopolamine.

The conformation of chloramphenicol in the ordered and disordered phases.

The conformational behavior of chloramphenicol (CHL) in the solid, liquid and vapor phases is revisited here by means of FTIR spectroscopy and QM methods. In the crystalline phase, both the IR analysis and QM computations discard the conformer proposed by Acharya et al. (Acta Cryst., 1979, B35:1360-1363) and support the one proposed by Chatterjee et al. (J. Cryst. Mol. Struct., 1979, 9:295-304), characterized by an intramolecular OH⋯O hydrogen bond in which the primary hydroxyl group acts as hydrogen bond donor. The conformational behavior of CHL in the liquid and gas phases has been analyzed using QM calculations. The Self-Consistent Reaction Field (SCRF) method with the Onsager solvation model has been used for the initial optimizations in solution, and the lowest energy conformers have been refined using the Solvation Model based on Density (SMD). In solution environment the intramolecular OH⋯O hydrogen bond in CHL is reversed so that the secondary hydroxyl group acts as hydrogen bond donor. In addition, the dichloroacetamide group folds back further over the phenyl ring to form an intramolecular CCl⋯π halogen bond. Two different halogen bonds are actually observed (each one with a different chlorine atom) resulting in two different stable conformers, that can be detected by FTIR spectroscopy due to the conformational sensitivity of the CO group to the conformation of the dichloroacetyl group. Finally, the stability of the conformers with the polarity of the medium is also discussed.

Theoretical Study of Solvent Effect on the Kinetics and Thermochemistry of the Reaction of a (NHC)Cu(boryl) Complex with Ethylene

In this investigation, we describe solvent effect on the ethylene insertion into Cu–B bond in a (NHC)Cu(boryl) complex using MPW1PW91 quantum chemical methods. Solvent effects were explored by using the self-consistent reaction field (SCRF) method based on polarizable continuum model (PCM) in cyclopentanol, acetone, methanol, nitromethane, and dimethylsulfoxide. The progress of the reaction was quantitatively studied using the bond orders of the C–C bond of ethylene, and the percentages of bond cleavage (BCCC) of C–C bond at the transition state were described. The linear correlations between barrier energy, bond distances variations and thermodynamic parameters with dielectric constants of solvents were investigated. Rate constant of the title reaction over the temperature range of 200–1200 K was calculated in gas phase.

Ab Initio Studies of Complexation of Gallic Acid in Aqueous Solutions

By an ab initio Hartree-Fock method at the (6-311+G*) level of theory the structural and energy characteristics of gallic acid (GA) complexes are calculated with and without taking into account the first hydration shell: GA–GA, GA–H2O, GA–H2O–GA and GA–H2O–GA (+6 water molecules), GA–GA (+8 water molecules). The calculations are carried out in the vacuum and aqueous solutions by the selfconsistent reaction field method (SCRF calculations). The solvent effect is studied using the Onsager model. The effect of the medium on the geometry, dipole moment, and stability of the considered complexes is estimated. The most stable structures of the complexes, their geometric parameters and atomic charges are determined and the vibrational spectra are calculated. In the aqueous medium, the GA–GA complex (ΔEint =–12.9758 kcal/mol) is found to be the most stable as compared to GA–H2O and GA–H2O–GA. It is shown that the involvement of solvent molecules as the first hydration shell significantly affects the structure and stability of GA complexes.

HEAT OF HYDRATION OF DIETHYLSULFONE BY QUANTUM CHEMICAL CALCULATION

The quantum chemical study of the hydration of diethyl sulfone was performed by using Gaussian 09 software package. The conformational analysis of the isolated molecule of diethyl sulfone is performed by the restricted Hartree-Fock (RHF) and the density functional theory (DFT/B3PW91) methods with 6-311++G(d,p) extended basis set. The analysis of the potential energy surface revealed the existence of four stable conformers of diethyl sulfone with different degrees of degeneracy. The nature of stationary points on the potential energy surface is verified by the complete gas phase optimization and the vibrational analysis. The global minimum is the conformer with two (CCSC) dihedral angles equal 180°. The fractional population distribution of different conformers is determined by Boltzmann distribution. The average energy of the diethyl sulfone molecule in vacuum is calculated. To account the effect of solvent the self-consistent reaction field (SCRF) method, particularly, solvent model based on electron density (SMD), was employed. It is shown, that solvent affects on the relative population of conformers. The thermodynamic parameters, in particular enthalpy, for the conformers of diethyl sulfone are determined both in the gas phase and in the aqueous solution. The average energy of diethyl sulfone in water is calculated. It is shown, that although the dissolution of crystalline diethyl sulfone in water is an endothermic process, the hydration of diethyl sulfone molecules occurs with the release of heat. The heat of dissolution of diethyl sulfone calculated by the density functional theory is consistent with the experimental data.

Theoretical Study of Tautomerization in 1,5-Dimethyl-6-Thioxo-1,3,5-Triazinane-2,4-Dione

In this work, the tautomeric transformations of a 1,5-dimethyl-6-thioxo-1,3,5-triazinane-2,4-dione molecule are explored at the M062X/6-311G(d,p) level of theory in gas and solution phases. These calculations show that the 1,5-dimethyl-6-thioxo-1,3,5-triazinane-2,4-dione isomer is more stable than its tautomer (4-hydroxy-1,5-dimethyl-6-thioxo-5,6-dihydro-1,3,5-triazin-2(1H)-one) in gas and solution phases. The frontier molecular orbitals and band gap energy calculations are performed at the M062X/6-311G(d,p) level in gas and various solvents. Solvent effects are analyzed using the self-consistent reaction field method based on the polarizable continuum model in chloroform, chlorobenzene, tetrahydrofurane, dichloromethane, and quinoline. The solvent effect on the N–H and C=O vibrations is explored. Also, natural bond orbital (NBO) analysis was used to understand the structure and bonding of the molecule.

Influence of inert matrixes on the conformational switching of trimethyl phosphate at low temperatures through thermal effects

The conformational switching of trimethyl phosphate (TMP) in Ne, Ar, Kr and Xe matrixes was studied using infrared spectroscopy under isolated conditions at low temperatures. In all the inert matrixes, the vapor phase population of ground state C3(G±G±G±) and the higher energy C1(TG±G±) conformers of TMP is preserved during the initial deposition. However, on annealing the inert Ar/Kr/Xe matrixes, the conformational composition of TMP was irreversibly altered. In Ar and Kr matrixes, an interconversion from ground state C3(G±G±G±) to higher energy C1(TG±G±) conformer was observed whereas Xe presents an interesting variation. In Xe matrix, the higher energy C1(TG±G±) conformer completely depopulated with a concomitant increase in the population of the ground state C3(G±G±G±) conformer. In Ne matrix notably, no conformational interconversion was observed. Computations on the conformers of TMP were performed using B3LYP and M06-2X levels of theory with 6-311++G(d,p) and aug-cc-pVDZ basis sets. The effect of inert matrixes was modeled using Self-Consistent Reaction Field (SCRF) methods.

Theoretical Study of Small Iron-Oxyhydroxide Clusters and Formation of Ferrihydrite.

Hydrolysis of iron compounds in water leads to the formation of Fe(III) oyxhydroxide-based minerals like ferrihydrite, which act as natural scavengers of inorganic contaminants in the environment. Though studied widely, experimental identification of these oxyhydroxides remains very difficult due to their extreme reactivity. The present study theoretically investigates the formation of Fe(III) oxyhydroxides starting from a single hydrated Fe(III) ion, modeling the formation of larger clusters gradually. The structures, formation enthalpies, and free energies of dimers, trimers, tetramers, and even larger Fe(III) oxyhydroxide clusters comprising of Fe5, Fe7, and Fe13-Keggin ions in gaseous phase and in aqueous medium (using self-consistent reaction field method) are systematically studied using density functional theory. Spontaneous formation of certain multinuclear Fe(III) oxyhydroxide clusters with clear structural signatures of ferrihydrite highlights their potential as prenucleation clusters in the course of mineralization.

Combining Explicit Quantum Solvent with a Polarizable Continuum Model.

A promising approach for accurately modeling both short-range and long-range solvation effects is to combine explicit quantum mechanical (QM) solvent with a classical polarizable continuum model (PCM), but the best PCM for these combined QM/classical calculations is relatively unexplored. We find that the choice of the solvation cavity is very important for obtaining physically correct results since unphysical double counting of solvation effects from both the QM solvent and the classical dielectric can occur with a poor choice of cavity. We investigate the dependence of electronic excitation energies on the definition of the PCM cavity and the self-consistent reaction field method, comparing results to large-scale explicit QM solvent calculations. For excitation energies, we identify the difference between the ground and excited state dipole moments as the key property determining the sensitivity to the PCM cavity. Using a linear response PCM approach combined with QM solvent, we show that excitation energies are best modeled by a solvent excluded surface or a scaled van der Waals surface. For the aqueous solutes studied here, we find that a scaled van der Waals surface defined by universal force field radii scaled by a factor of 1.5 gives reasonable excitation energies. When using an external iteration state-specific PCM approach, however, the excitation energies are most accurate with a larger PCM cavity, such as a solvent accessible surface.

Molecular structure, vibrational spectroscopic analysis (IR & Raman), HOMO-LUMO and NBO analysis of anti-cancer drug sunitinib using DFT method

Oxindole and its derivatives have wide applications in different industries such as in synthetic & natural fibers, dyes for hair and plastic materials in addition to their biological importance. In the present study, one of the oxindole derivatives, N-(2-diethylaminoethyl)-5-[(Z)-(5-fluoro-2-oxo-1H-indol-3-ylidene)methyl]-2,4-dimethyl-1H-pyrrole-3-carboxamide (Sunitinib), which is used as an anti-cancer drug, was investigated in terms of structural, vibrational spectroscopic and theoretical analysis. The calculations have been performed for gaseous, aqueous and DMSO phases, respectively. Potential Energy Surface (PES) scan has been carrried out to obtain the most stable structures of all the phases of the title molecule using B3LYP/6-31G(d,p) level and the geometrical variations among them are discussed. The solvent effect for Sunitinib in aqueous and DMSO phases have been performed by means of the self-consistent recognition reaction field (SCRF) method as implemented in the integral equation formalism polarized continuum model (IEFPCM). On the other hand, NBO analysis has been carried out to understand probable hydrogen bonding sites and charge transfers. Additionally, the HOMO and the LUMO energies are calculated using B3LYP/6-31G(d,p) to determine the intra molecular charge transfers (ICT) within the molecule and the kinetic stabilities for each phases. The molecular electrostatic potential surface (MESP) has been plotted over the optimized structure to estimate the reactive sites of electrophilic and nucleophilic attacks regarding Sunitinib molecule. The potential energy distribution (PED) has been calculated using VEDA4 program and vibrational assignments of the experimental spectra (IR & Raman) have been elucidated by means of the calculated vibrational spectra. The observed vibrational spectra of Sunitinib is compared with the calculated spectra obtained by using B3LYP functional both with 6-31G(d,p) and 6-311++G(d,p) basis sets. Theoretical results indicate that the best correlation with experimental data is obtained with B3LYP/6-311++G(d,p) method.