cyclohexane-1-carboxylic acid is a synthetic derivative of the amino acid lysine that exerts its antifibrinolytic effect through the reversible blockade of the lysine binding sites on plasminogen molecules (Thoresen et al., 1981). TA is useful in a wide range of haemorrhagic conditions. The drug reduces postoperative blood losses and transfusion requirements in a number types of surgery (Brown et al., 1997 and Ido 2004), with potential cost and tolerability advantages aprotinin, and appears to reduce rates of mortality and urgent surgery in patients with upper gastrointestinal haemorrhage. TA reduces menstrual blood loss and is a possible alternative to surgery in menorrhagia and has been used successfully to control bleeding in pregnancy. In the present study, FT FT-Raman spectral investigation of TA has been performed using density functional theory (DFT). The redistribution of electron density (ED) in various bonding and antibonding orbital and E(2) energies have been calculated by natural bond orbital (NBO) analysis by DFTmethod to give clear evidence of stabilization originating from the hyper conjugation of various intra-molecular interactions. The HOMO and LUMO analysis have been used to elucidate information regarding charge transfer within the molecule.
DFTmethod is more advance and gave better results than Hartree-Fock calculations. Quantum mechanical frame work of HSAB principle was given by Klopmann. The values of Em# for the two nitrogen’s were calculated, by applying DFT, which gave important results about the activity.
same range. So it gives confirmation of COOH group. Herbicides Bromoxynil and its four derivatives are discussed. With the calculation of dipole moment bromoxynil has found with minimum retention time in soil and minimum contamination in soil and food materials. With Entropy and Total thermal energy calculation it is found that D-1 has maximum value of entropy and total thermal energy. Hence Derivative-1(3, 5-Dibromo-4-methoxy benzoic acid) is the most effective herbicide. Moreover chemical D-3(2, 6-Dibromo phenol) has minimum value of entropy and total thermal energy, so it is the least effective herbicide among all the chemicals taken. The values for vibrational frequency of all the functional groups in IR spectra of all the chemicals taken by Gaussian are compared with the experimental values of functional group gives the same result. So the IR spectra taken by Gaussian give the valid results. We can study the path of action of herbicide by taking IR spectra using DFTmethod.
Because all the calculations are theoretically physical chemistry is the best way to get to the key points and detailed empirical search of porphyrins in the laboratory of molecular ion with gaussian03 method. The structure of each species in this research include; porphyrin, metal ions attached to porphyrin and Metal ions bonded dimer of them were optimized fully by restricted B3LYP with 3-21G ‚ 6-31G and 6-311++G** levels and gaussian03 package. Energy parameters, IR spectrum of each species were calculated through using method and basis set described beforehand. In the search of quantum mechanical study of the interaction of metal ions with porphyrin by DFTmethod in the field of software where not detail checked.
scattering (INS) experiment has been reported under such high pressure. Marqués et al. conducted a first-principles study of phonon frequencies . Their density functional theory (DFT) calculations illustrate that ice X is not molecular in character and is linked by soft phonon transitions to ice VIII (or disordered ice VII) at low pressure and to a putative Pn3m structure at high pressure . In addition, the calculated phonon frequencies in their work indicate that ice X is a stable phase, but with the pressure decreasing below 110 GPa, the dispersion curve changes significantly. Putrino and Parrinello theoretically reported a Raman peak at 840 cm -1 . Alexander  and Men  observed
The chitosan constituents considered in this study are denoted as A for the monomer, AA for the dimer and AAA for the trimer glucosamine molecules. The structural parameters of the A, AA, and AAA have been obtained using electron density functional theory (DFT) with the Becke–Lee–Yang–Parr functional (B3LYP) and polarized split-valence basis set 6-31G(d, p). Firefly Quantum Chemical package, version 8.0.0  which is partially based on the GAMESS (US) source code  has been used. Firefly as a versatile computation package allowed us to determine the equilibrium structure, i.e. a structure that represents a minimum on a potential energy surface. With this calculation, the internal coordinates such as the internuclear distances, valence angles and the torsion angles, were obtained. This process was followed by a hessian calculation to calculate the vibrational spectra. In this step, the vibrational frequencies and IR intensities were computed.
Among the various possibilities constrained DFT (CDFT) represents a conceptually different approach to the problem. The idea behind CDFT is that one can always define an appropriate density functional, implementing a given desired constraint on the charge density 32 (e.g., one can demand that an electron is localized on a particular group in a molecule). This is obtained by introducing an appropriate external potential in the Kohn-Sham equations. The crucial point is that the approach is fully variational, meaning that the energy minimum of the constrained functional represents the ground state of the system under that particular constraint. 33–35 The method allows, for example, to access energies and electron density distributions of charge-transfer states of a given system, and has been successfully applied to the study of long- range charge-transfer excitations between molecules. 33,36,37
In 2006, by a kinetic study, identified the hydroxyl (OH) group of trolox as the site of its antioxidant properties. The complexity of the exercise of evaluating the antiradical strength of plant extracts was clearly highlighted which demonstrated in 2011 that the manifestation of the antioxidant activity of molecule also depends on the other molecules present in the reaction medium, even if the latter do not possess any anti-radical activity. From the theoretical point of view, results have also been published in the literature on trolox, ascorbic acid and BHT. Using the DFTmethod, Dvood Farmanzadeh et al. showed in 2016, that the substitution of methyl group for ortho or meta of trolox by the NH2, OH and NHMe groups lowers the antioxidant power of the trolox derivatives. By calculations made at the approximation level B3LYP / 6-31 + G (d, p), a linear correlation was found between the HOMO energy, the length of the C-O bond and the spin density of trolox oxygen atom and the BHT when these molecules trap the DPPH radical. The work of these authors also revealed that the hydroxyl groups are the sites of manifestation of the antioxidant properties of each of these molecules. The objective of this work is to carry out a comparative study of the antioxidant properties of trolox, ascorbic acid and BHT, by the methods of quantum chemistry. For this, different electronic and energy parameters have been calculated and the results will make it possible to deduce the best reference molecule that can be used to evaluate the antioxidant properties of natural bioactive or synthetic molecules.
The recent wide importance of 2 ‐ propenoylamides [1,2], 2 propenoates [3 ‐ 6], besides, the interesting biological and pharmacological activities of many heterocyclic systems, like, benzoxazoles , pyrimidines , pyridopyrimidines  and pyrazoles encourage the authors to gather these moieties hoping to produce a valuable new compounds of expected antibacterial and antifungal activity. We report here the physical properties of the hetrocyclic acrylic derivatives by using DFTmethod. Also this modified method is fast, more accuracy for this field .
The DFTmethod is used to study the cis and trans conformers of cysteine, serine, threonine, and valine amino acids. The selection of DFT functional for the studies on H-bonded systems is a difficult task. One must be careful for the selection of DFT functional for the studies on H-bonded systems. Because, many number of DFT functionals available recently, which ranges from local density approximation (LDA) to hybrid meta generalized gradient approximation (hybrid meta-GGA) methods. In order to study H-bonded systems by DFT functional, the functional must contain dispersion term. In H-bond dispersion forces play important role. There is a significant difference in energy values, calculated by the functional with and without dispersion term. In our study we have selected Becke’s three parameter exact exchange functional (B3)  combined with gradient corrected correlation functional of Lee-Yang-Parr (LYP) . Our earlier study  has shown that, this functional produces reasonable result for the studies on H-bonded systems. In order to avoid the basis set to affect the relative energy, the calculations have been performed using higher 6-311++G** basis set. To study the cis–trans isomerization of the amino acids, the potential energy surface scan have been employed for the cis conformer of the amino acids in B3LYP/6-311++G** level of theory. The torsional angle ω(OCOH) is varied in steps of 30 o between ω=0 o (cis)
Simulation1: We compare the spectra of the proposed method, DFTmethod with the nested array as shown in Figure 2, where SNR 0 dB , L 500 . Note that the searching step is 0.01.The figure above in the Figure. 2 shows the spectra of DFT,and the following one is the spectra of the proposed method.
 . However, in recent years a number of works appeared   in which it was shown that the hypo- thesis of existence of universal density functional was incorrect, and that first of all it concerned the functional of kinetic energy (FKE). Nevertheless, the problem of development of the efficient approach for the OF-modeling of polyatomic systems remains tempting and actual. In our recent papers  , we have showed how it is possible, using single-atoms calculations by the Kohn-Sham DFTmethod (KS-DFT) , to find numerically the kinetic energy functionals for atoms, and then to use them for orbital-free modeling of atomic interactions. We calculated equilibrium distances, and binding energies for dimers contained Al, Si, and P atoms. Now we present an expansion of our method for other sp-species.
result is in full agreement with experimental . The fi rst conclusion, which must drawn is that DDT and heptachlor pesticides cannot be dehalogenated in one reducing electrochemistry step. This confi rms the experimental data of the stepwise removal of the halogen atoms from polyhalogenated organic molecules [11,14]. A second conclusion regarding the geometry optimization of these four ions is that after the fi rst dehalogenation step they form radicals at the carbon atoms of the former C-Cl bonds. These radicals would participate in various recombination and coupling reactions with the neighbouring molecules and ions. In conclusion, the next several steps of the dehalogenation of DDT and heptachlor pesticides must be studied only by using DFTmethod in straight connection with the results of the experimental electrochemical and analytical methods regarding the behavior of the formed ions after the fi rst electrochemical dehalogenation.
The binding free energy of the optimized molecules is calculated by performing molecular simulation by DFTmethod. The molecule with minimum binding energy will have the maximum binding affinity and higher biological active. According to this more negative value, we can consider a more effective drug. In this case CBV is less biological active than CBL.
In this research study, the DFTmethod was used to characterize and optimize the palladium (II) complex ions with binuclear amine ligands and the thermophysical and chemical and biological properties were recorded. The vibration, degeneracy, symmetry, and splitting of d orbitals provided information in the analytical method. In the case of HOMO, LUMO, and HOMO–LUMO gap can be informed that palladium (II) complex ions with binuclear amine ligands are chemically reactive for further uses. As the value of LogP was negative, palladium (II) complex ions with binuclear amine ligands are hydrophilic nature. This is why the toxicity was very low, supporting the safe uses in all areas
(Received 28 December 2018, revised 6 September, accepted 16 September 2019) Abstract: Recently, substituted 1,8-dioxodecahydroacridine derivatives have been investigated and found to possess a wide variety of biological and phar- macological activities. Two of these biologically relevant N-heterocyclic scaf- folds, 2-(9-(4-methoxyphenyl)-3,3,6,6-tetramethyl-1,8-dioxo-1,2,3,4,5,6,7,8- -octahydroacridin-10(9H)-yl)succinic acid (MTDOSA) and 2-(3,3,6,6-tetra- methyl-9-(4-nitrophenyl)-1,8-dioxo-1,2,3,4,5,6,7,8-octahydroacridin-10(9H)-yl)- succinic acid (NTDOSA), have been studied in ground and first excited state using DFTmethod employing B3LYP/6-311++G(d,p) level of theory. Quan- tum chemical calculations of geometrical structure and vibrational wave- numbers of MTDOSA and NTDOSA were carried out using DFTmethod. The experimental FT-IR spectra of the compounds were recorded in the range 4000–400 cm -1 and comprehensively interpreted on the basis of potential
Dirac-particles with a linear dispersion, simply absorption coefficient of lights and transport energy gap [7, 8]. Investigations of the structural and electric properties of some graphene/metal interfaces, still not completely understood. Such studies required a careful review of the growth protocols reported in the literature to reproduce them and thereby fully control the features of the interfaces. The attention was devoted in particular to the electronic (filled and empty) states of graphene. However, the density functional theories (DFT) investigate the reaction barrier reduction for the adsorption of atomic hydrogen at linear bends in graphene.
cessfully synthesized by the ligand exchange method using oxorhenuim citrate and an imida- zole /Hydanton mixed ligand system. Geometry optimization of complex has been carried out using DFT at the B3LYP/LANL2DZ functional in singlet state. B3LYP predicated infrared spec- trum of the geometrically optimized structure using the same level of the theory and the same base set showed good agreement with experi- mentally observed values. The spin allowed singlet-singlet electronic transition of the [ReO(Imz)(Hyd) (H 2 O) 2 OH] complex was calcu-
In DCT, the generation of an even symmetric periodic sequence removes the discontinuity as the symmetric signal moves from one period to the next period smoothly. As a result, like the DFT, the DCT does not suffer from leakage effects or Gibbs ripple.