Absolute Electronegativity Research Articles

Quantum chemical investigation on structures and energetics of Tungsten Fluoride (WF $_{\boldsymbol {n}}^{~\boldsymbol {q}}$ ) species (q = 0, ±1; n < 6)

The present work deals with a systematic study on WF n species using ab initio density functional method. The geometrical features related to the equilibrium structures of WF n species up to n = 5 are highlighted and the effect of addition as well as removal of an electron is discussed. The chemical stability of these species is discussed by calculating their HOMO-LUMO energy gap and binding energy per atom. The frontier molecular orbital surfaces are also analyzed. The energy based electronic properties such as ionization potential, electron affinity, absolute electronegativity and chemical hardness are also evaluated which provide insights into chemical reactivity of these species. Density functional theory calculations show that the ionization potential (IP) and electron affinity (EA) of tungsten fluorides (WF n ) change remarakably with the increase in F atoms which explains the variation in their chemical reactivity.

Exploring the role of quantum chemical descriptors in modeling acute toxicity of diverse chemicals to Daphnia magna

Various quantum-mechanically computed molecular and thermodynamic descriptors along with physico-chemical, electrostatic and topological descriptors are compared while developing quantitative structure–activity relationships (QSARs) for the acute toxicity of 252 diverse organic chemicals towards Daphnia magna. QSAR models based on the quantum-chemical descriptors, computed with routinely employed advanced semi-empirical and ab-initio methods, along with the electron-correlation contribution (CORR) of the descriptors, are analyzed for the external predictivity of the acute toxicity. The models with reliable internal stability and external predictivity are found to be based on the HOMO energy along with the physico-chemical, electrostatic and topological descriptors. Besides this, the total energy and electron-correlation energy are also observed as highly reliable descriptors, suggesting that the intra-molecular interactions between the electrons play an important role in the origin of the acute toxicity, which is in fact an unexplored phenomenon. The models based on quantum-chemical descriptors such as chemical hardness, absolute electronegativity, standard Gibbs free energy and enthalpy are also observed to be reliable. A comparison of the robust models based on the quantum-chemical descriptors computed with various quantum-mechanical methods suggests that the advanced semi-empirical methods such as PM7 can be more reliable than the ab-initio methods which are computationally more expensive.

SELECTION OF SULFHYDRIL COLLECTORS FOR FLOTATION OF SULFIDES OF NONFERROUS METALS FROM REFRACTORY ORES OF NONFERROUS METALS

Methods of selection of selective collectors are analyzed. The procedure of calculation of characteristics of absolute rigidity, absolute electronegativity, and reaction ability of compounds is presented. The correspondence between the results of theoretical calculations of the reaction ability of sulfhydril collectors and experimental results of adsorption and flotation of monomineral fractions of chalcopyrite, galenite, and pyrite by sulfhydril collectors is revealed. The prediction of the collecting activity based on calculations is complicated by the features of the chemical composition of natural sulfides and defectiveness of the surface associated with the genesis of ore minerals in the deposit is revealed. Dithiophosphates and thionocarbamates are isolated as main components of selective compositions of collectors for flotation of pyrite ores of nonferrous metals based on theoretical and experimental investigations. It is shown by the complex of adsorption investigations in conditions of nonfrothing flotation and analysis of the IR frustrated total internal reflection (FTIR) spectra of concentrates of nonfrothing flotation that the nonoptimal ratio of components weakly active relative to pyrite leads to a considerable increase in pyrite floatability. Sorption of components of the sulfhydril collector and pyrite floatability increase with the fraction of a nonionogenic collector in the composition lower than 40–60%. The action mechanism, which determines the action selectivity of sulfhydril collectors during the flotation of sulfides, is determined.

Externally predictive single-descriptor based QSPRs for physico-chemical properties of polychlorinated-naphthalenes: Exploring relationships of log SW, log KOA, and log KOW with electron-correlation

Quantitative structure–property relationships (QSPRs), based only on a single-parameter, are proposed for the prediction of physico-chemical properties, namely, aqueous solubility (logSW), octanol–water partition coefficient (logKOW) and octanol–air partition coefficient (logKOA) of polychloronaphthalenes (PCNs) including all the 75 chloronaphthalene congeners. The QSPR models are developed using molecular descriptors computed through quantum mechanical methods including ab-initio as well as advanced semi-empirical methods. The predictivity of the developed models is tested through state-of-the-art external validation procedures employing an external prediction set of compounds. To analyse the role of instantaneous interactions between electrons (the electron-correlation), the models are also compared with those developed using only the electron-correlation contribution of the quantum chemical descriptor. The electron-correlation contribution towards the chemical hardness and the LUMO energy are observed to be the best predictors for octanol–water partition coefficient, whereas for the octanol–air partition coefficient, the total electronic energy and electron-correlation energy are found to be reliable descriptors, in fact, even better than the polarisability. For aqueous solubility of PCNs, the absolute electronegativity is observed to be the best predictor. This work suggests that the electron-correlation contribution of a quantum-chemical descriptor can be used as a reliable indicator for physico-chemical properties, particularly the partition coefficients.

Selection of sulfhydryl collectors for flotation of sulfides of nonferrous metals from refractory ores of nonferrous metals

Methods of selection of selective collectors are analyzed. The procedure for calculating characteristics of absolute rigidity, absolute electronegativity, and reaction ability of compounds is presented. The correspondence between the results of theoretical calculations of the reaction ability of sulfhydryl collectors and experimental results of adsorption and flotation of monomineral fractions of chalcopyrite, galenite, and pyrite by sulfhydryl collectors is revealed. The prediction of the collecting activity based on calculations is complicated by the features of the chemical composition of natural sulfides, and the defectiveness of the surface associated with the genesis of ore minerals in the deposit is revealed. Dithiophosphates and thionocarbamates are isolated as main components of the selective compositions of collectors for the flotation of pyrite ores of nonferrous metals based on theoretical and experimental investigations. It is shown by a complex of adsorption investigations in conditions of nonfrothing flotation and analysis of the IR frustrated total internal reflection (ATR) spectra of concentrates of nonfrothing flotation that the nonoptimal ratio of components weakly active relative to pyrite leads to a considerable increase in pyrite floatability. The sorption of components of the sulfhydryl collector and pyrite floatability increase when the fraction of a nonionogenic collector in the composition is lower than 40–60%. The action mechanism, which determines the action selectivity of sulfhydryl collectors during the flotation of sulfides, is determined.

Thermal, dielectric characteristics and conduction mechanism of azodyes derived from quinoline and their copper complexes

A novel series of (5-(4′-derivatives phenyl azo)-8-hydroxy-7-quinolinecarboxaldehyde) (AQLn) (n=1, p-OCH3; n=2, R=H; and n=3; p-NO2) and their complexes [Cu(AQLn)2]·5H2O are synthesized and investigated. The optimized bond lengths, bond angles and the calculated quantum chemical parameters for AQLn are investigated. HOMO–LUMO energy gap, absolute electronegativities, chemical potentials, and absolute hardness are also calculated. The thermal properties, dielectric properties, alternating current conductivity (σac) and conduction mechanism are investigated in the frequency range 0.1–100kHz and temperature range 293–568K for AQL1–3 and 318–693K for [Cu(AQL1–3)2]·5H2O complexes. The thermal properties are of ligands (AQLn) and their Cu(II) complexes investigated by thermogravimetric analysis (TGA). The temperature and frequency dependence of the real and the imaginary part of the dielectric constant are studied. The values of the thermal activation energy of conduction mechanism for AQLn and their complexes [Cu(AQLn)2]·5H2O under investigation are calculated at different test frequencies. The values of thermal activation energies ΔE1 and ΔE2 for AQLn and [Cu(AQLn)2]·5H2O decrease with increasing the values of frequency. The ac conductivity is found to be depending on the chemical structure of the compounds. Different conduction mechanisms have been proposed to explain the obtained experimental data. The small polaron tunneling (SPT) is the dominant conduction mechanism for AQL1 and its complex [Cu(AQL1)2]·5H2O. The quantum mechanical tunneling (QMT) is the dominant conduction mechanism for AQL2 and its complex [Cu(AQL2)2]·5H2O. The correlated barrier hopping (CBH) is the dominant conduction mechanism for AQL3 and its complex [Cu(AQL3)2]·5H2O, and the values of the maximum barrier height (Wm) are calculated.

Density functional theory studies on the corrosion inhibition of benzoin, benzil, benzoin-(4-phenylthiosemicarbazone) and benzil-(4-phenylthiosemicarbazone) of mild steel in hydrochloric acid

The density functional theory (DFT) calculations were performed on benzoin (BN), benzil (BL), benzoin-(4-phenylthiosemicarbazone) (BN4PTSC) and benzil-(4-phenylthiosemicarbazone) (BL4PTSC) used as corrosion inhibitors for mild steel in acidic medium. The quantum chemical parameters/descriptors, namely, E HOMO (highest occupied molecular orbital energy), E LUMO (lowest unoccupied molecular orbital energy), the energy difference (ΔE) between E HOMO and E LUMO, dipole moment (μD), electron affinity (A), ionization potential (I), the absolute electronegativity (χ), absolute hardness (η), softness (σ), polarizability (α), the Mulliken charges, and the fraction of electrons (ΔN) transfer from inhibitors to iron, were calculated and correlated with the experimental IE%. Condensed Fukui functions have been used to determine the sites for electrophilic and nucleophilic attacks on each of the inhibitors.

Quantum Chemical Study on the Corrosion Inhibition of Some Oxadiazoles

Quantum chemical calculations based on DFT method were performed on three nitrogen-bearing heterocyclic compounds used as corrosion inhibitors for the mild steel in acid media to determine the relationship between the molecular structure of inhibitors and inhibition efficiency. The structural parameters, such as energy and distribution of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), the charge distribution of the studied inhibitors, the absolute electronegativity (χ) values, and the fraction of electrons (ΔN) transfer from inhibitors to mild steel were also calculated and correlated with inhibition efficiencies. The results showed that the inhibition efficiency of inhibitors increased with the increase in energy of HOMO and decrease in energy gap of frontier molecular orbital, and the areas containing N and O atoms are most possible sites for bonding the steel surface by donating electrons to the mild steel.

Study on structures and electronic properties of NaxV (x=1-12) atomic clusters

Superatoms, novel entities being studied extensively in recent years, can be stabilized by mixing with transition metal atoms. The aim of this paper is to present some recent theoretical results on the application of quantum calculations for examining the atomic clusters NaxV (x=1-12) made from the mixing of Nax superatoms with vanadium transition metal atom. Optimized structures of NaxV, NaxV+ and NaxV- are determined by using the TPSSTPSS / DZVP DFT calculations. Characteristics of optimized structures, as point group symmetry, chemical hardness (η), absolute electronegativity (χ), electrophilicity index (ω), fragmentation energy (Ef), secondary energy (∆2E), are calculated. The obtained results point out that among different structures of an atomic cluster, the more negative total energy the more stable structure and the Na8V cluster is the most stable in NaxV (x=1-12) clusters.

Single-descriptor based quantum-chemical QSPRs for physico-chemical properties of polychlorinated-dibenzo-p-dioxins and -dibenzo-furans (PCDD/Fs): Exploring the role of electron-correlation

In this work, we propose and analyze single-descriptor based quantitative structure–property relationships (QSPRs) developed using quantum-chemical descriptors and their electron-correlation contribution, for various physico-chemical properties, namely, aqueous solubility, subcooled liquid vapour pressure, n-octanol/water and n-octanol/air partition coefficients of polychlorinated-dibenzo-p-dioxins (PCDDs) and -dibenzo-furans (PCDFs). The predictivity of the developed QSPRs is examined through external validation procedures employing an external prediction set of chemicals not used in the QSPR model development. From the comparison of different models, it is observed that the total energy and the mean polarizability of a molecule are highly significant in determining the predictivity of a QSPR, whereas dipole moment is found to be a poor descriptor in the models developed for all the properties analyzed. Besides these, the electron density based descriptors, namely, absolute electronegativity and electrophilicity index, were also observed to be highly influential in determining the external prediction for partition coefficients.

Relationship of mineralization of amino naphthalene sulfonic acids by Fenton oxidation and frontier molecular orbital energies

Six amino naphthalene sulfonic acids including mono-, di- and tri-sulfonic acid compounds were studied to find the relationship between the reactivity of this kind of compounds in Fenton oxidation process and energies of the frontier molecular orbital. It was found that the initial rates of TOC reduction and oxalic acid production correlated strongly to the frontier molecular orbital energies and can be estimated by EHOMO and the absolute electronegativity (χ). The cleavage of –SO3H and –NH2 groups to produce SO42− and NH4+ species was dependent on the electron density distribution on the –SO3H moiety and the α-carbon atom connecting the –NH2 moiety. The electron withdrawing effect of the –SO3H groups influenced the mineralization of naphthalene sulfonic acids significantly. The naphthalene sulfonic acid with more –SO3H groups was more recalcitrant to the Fenton oxidation.

Electron-correlation based externally predictive QSARs for mutagenicity of nitrated-PAHs in Salmonella typhimurium TA100

In quantitative modeling, there are two major aspects that decide reliability and real external predictivity of a structure–activity relationship (SAR) based on quantum chemical descriptors. First, the information encoded in employed molecular descriptors, computed through a quantum-mechanical method, should be precisely estimated. The accuracy of the quantum-mechanical method, however, is dependent upon the amount of electron-correlation it incorporates. Second, the real external predictivity of a developed quantitative SAR (QSAR) should be validated employing an external prediction set. In this work, to analyze the role of electron-correlation, QSAR models are developed for a set of 51 ubiquitous pollutants, namely, nitrated monocyclic and polycyclic aromatic hydrocarbons (nitrated-AHs and PAHs) having mutagenic activity in TA100 strain of Salmonella typhimurium. The quality of the models, through state-of-the-art external validation procedures employing an external prediction set, is compared to the best models known in the literature for mutagenicity. The molecular descriptors whose electron-correlation contribution is analyzed include total energy, energy of HOMO and LUMO, and commonly employed electron-density based descriptors such as chemical hardness, chemical softness, absolute electronegativity and electrophilicity index. The electron-correlation based QSARs are also compared with those developed using quantum-mechanical descriptors computed with advanced semi-empirical (SE) methods such as PM6, PM7, RM1, and ab initio methods, namely, the Hartree-Fock (HF) and the density functional theory (DFT). The models, developed using electron-correlation contribution of the quantum-mechanical descriptors, are found to be not only reliable but also satisfactorily predictive when compared to the existing robust models. The robustness of the models based on descriptors computed through advanced SE methods, is also observed to be comparable to those developed with the electron-correlation based descriptors. The work emphasizes that the correlation-energy can serve as a reliable descriptor to explore the origin of biological activities at the level of electron-dynamics.

Quantum Chemical Studies on the Corrosion Inhibition of Mild Steel by Piperidin-4-One Derivatives in 1 M H<sub>3</sub>PO<sub>4</sub>

The corrosion inhibition properties of 2,6-diphenylpiperidin-4-one (DPP) (1A) and 2,6-diphenyldihydro-2H-thiopyran-4(3H)-one (DPDT) (1B) for mild steel in 1 M phosphoric acid were studied using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopic techniques. The effect of temperature on the corrosion behavior of mild steel has been examined in the temperature range 303 - 328 K. The inhibition efficiency increases with increasing inhibitor concentration but decreases with increasing temperature. Potentiodynamic polarization studies indicated the mixed nature of inhibitors. The adsorption of the inhibitors on mild steel surface obeyed the Langmuir adsorption isotherms. The density functional theory (DFT) at the B3LYP/6- 31G (d) basis set level was performed on 1A and 1B to investigate the correlation between molecular structure and the corresponding inhibition efficiency (%). The quantum chemical parameters such as EHOMO, ELUMO, the energy gap (E), hardness (η), softness (S), dipole moment (μ), electron affinity (A), ionization potential (I), the absolute electronegativity (χ), the fraction of electron transferred (N), electrophilicity index (ω), the back-donation (EBack-donation) and Mulliken population analysis have been calculated.

DFT Calculations for Corrosion Inhibition of Ferrous Alloys by Pyrazolopyrimidine Derivatives

The inhibition performance of 5-tolyl-2-phenylpyrazolo[1,5-c] pyrimidine-7(6H)thione (Tolyl), 5-tolyl-2-pheenylpyrazolo [1,5-c]pyrimidine-7(6H)one (Inon) was investigated as corrosion inhibitors using density functional theory (DFT) at the B3LYP/6-31 + G(d,p) level of theory. The calculated quantum chemical parameters correlated to the inhibition efficiency are: the highest occupied molecular orbital energy(EHOMO), the lowest unoccupied molecular orbital energy (ELUMO), the energy gap (ΔEL-H), dipole moment (μ), ionization energy (Ι), electron affinity (Α), absolute electronegativity (χ), absolute hardness (η), absolute softness (σ), the fraction of electron transferred (ΔN), and the total energy (Etot) which were calculated. The local reactivity has been analyzed through the Fukui function and local softness indices in order to compare the possible sites for nucleophilic and electrophilic attacks. The success of DFT calculations in predicting the inhibition efficiency was assessed.

Using experimental data of Escherichia coli to develop a QSAR model for predicting the photo-induced cytotoxicity of metal oxide nanoparticles

A quantitative structure–activity relationship (QSAR) study of seventeen metal oxide nanoparticles (MNPs), in regard to their photo-induced toxicity to bacteria Escherichia coli, was developed by using quantum chemical methods. A simple and statistically significant QSAR model (F=33.83, R2=0.87) was successfully developed for the dark group based on two descriptors, absolute electronegativity of the metal and the metal oxide. Similarly, a best correlation (F=20.51, R2=0.804) was obtained to predict the photo-induced toxicity of MNPs by using two descriptors, molar heat capacity and average of the alpha and beta LUMO (lowest unoccupied molecular orbital) energies of the metal oxide. Revelation of these influential molecular descriptors may be useful in elucidating the mechanisms of nanotoxicity and for predicting the environmental risk associated with release of the MNPs. In addition, the developed model may have a role in the future design and manufacture of safe nanomaterials.

Externally predictive quantitative modeling of supercooled liquid vapor pressure of polychlorinated-naphthalenes through electron-correlation based quantum–mechanical descriptors

For predicting physico-chemical properties related to environmental fate of molecules, quantitative structure–property relationships (QSPRs) are valuable tools in environmental chemistry. For developing a QSPR, molecular descriptors computed through quantum–mechanical methods are generally employed. The accuracy of a quantum–mechanical method, however, rests on the amount of electron-correlation estimated by the method. In this work, single-descriptor QSPRs for supercooled liquid vapor pressure of chloronaphthalenes and polychlorinated-naphthalenes are developed using molecular descriptors based on the electron-correlation contribution of the quantum–mechanical descriptor. The quantum–mechanical descriptors for which the electron-correlation contribution is analyzed include total-energy, mean polarizability, dipole moment, frontier orbital (HOMO/LUMO) energy, and density-functional theory (DFT) based descriptors, namely, absolute electronegativity, chemical hardness, and electrophilicity index. A total of 40 single-descriptor QSPRs were developed using molecular descriptors computed with advanced semi-empirical (SE) methods, namely, RM1, PM7, and ab intio methods, namely, Hartree–Fock and DFT. The developed QSPRs are validated using state-of-the-art external validation procedures employing an external prediction set. From the comparison of external predictivity of the models, it is observed that the single-descriptor QSPRs developed using total energy and correlation energy are found to be far more robust and predictive than those developed using commonly employed descriptors such as HOMO/LUMO energy and dipole moment. The work proposes that if real external predictivity of a QSPR model is desired to be explored, particularly, in terms of intra-molecular interactions, correlation-energy serves as a more appropriate descriptor than the polarizability. However, for developing QSPRs, computationally inexpensive advanced SE methods such as PM7 can be more reliable than the expensive ab inito methods.

Quantum mechanical study of the structure and spectroscopic (FT-IR, FT-Raman, 13C, and 1H) and HOMO–LUMO analysis of 2,4-dimethoxy benzaldehyde (DMBA) and 4-methoxy-3-methyl benzaldehyde (MMBA)

The present communication is aimed at comparing the molecular structural properties, vibrational and energetic data of 2,4-dimethoxy benzaldehyde and for 4-methoxy-3-methyl benzaldehyde, due to their commercial importance. The ground state properties of the title molecules have been calculated employing DFT/B3LYP level of theory using the 6-31G (d) basis set. In order to obtain a complete description of molecular dynamics, vibrational wavenumber calculation along with the normal mode analysis, have been carried out at the DFT level. The calculated spectra of both the molecules agree well with the experimental data. The 1H and 13C NMR spectra have been simulated using the gauge independent atomic orbital (GIAO) method. The electronic properties, such as HOMO, LUMO energies, absolute electronegativity X and absolute hardness η were performed by DFT approach. The first order hyperpolarizability (βo) of these novel molecular system and related properties (β, αo and Δα) of DMBA and MMBA are calculated using DFT/6-31G (d) method on the finite-field approach.

Lewis and Brönsted acidic sites in M4+-doped zeolites (M = Ti, Zr, Ge, Sn, Pb) as well as interactions with probe molecules: A DFT study

Tetravalent-ion (M4+)-doped zeolites show excellent performances for a variety of catalytic processes, including the focusing biomass conversions. In this work, density functional calculations were performed to probe the Lewis and Brönsted acidities of various M4+-doped zeolites as well as to study interactions with probe molecules. The Lewis and Brönsted acidities increase in the orders of Silicalite-1≪Ge<Ti<Pb<Sn<Zr and Silicalite-1≪Ti<Ge<Zr≈B<Pb<Sn<Al, respectively. The Lewis acidities should be defined as the local sites around the M4+ ions, explaining why the adsorption energies give a more consistent order with LUMO energies and absolute electronegativity rather than fukui functions. The formation of Brönsted acidic sites is facilitated by doping with M4+ ions. Albeit the Brönsted acidities of these M4+-doped zeolites change greatly with Sn being the strongest, their strengths are far below that of Al3+. The interactions of five probe molecules of changing basicities with the Brönsted acidic sites indicate that the formations of covalent and/or ionic structures are the proton-competing results: the covalent and ionic structures co-exist only for trimethyphosphine and pyridine of comparable basicity; otherwise, proton transfer will take place and result in only the ionic or covalent structures. The proton affinity fails to predict the Brönsted acidity of Zr and is evidenced, especially by formation of the covalent structure during pyridine adsorption. Thus, this work presents a dynamic image of acid–base interactions and aids our understanding toward the catalysis of solid-state acids.

Quantum chemical studies on some thiadiazolines as corrosion inhibitors for mild steel in acidic medium

Density functional theory at the B3LYP/6-31G(d,p) basis set level was performed on three thiadiazolines, namely 4-chloro-N-(5-phenyl-1,3,4-thiadiazol-2(3H)-ylidene)aniline (TD01), 4-chloro-N-(5-(4-methoxyphenyl)-1,3,4-thiadiazol-2(3H)-ylidene)aniline (TD02), and 2-(5-(4-chlorophenylimino)-4,5-dihydro-1,3,4-thiadiazol-2-yl) phenol (TD03), and the inhibitive effect of these thiadiazolines against the corrosion of mild steel in acidic medium is elucidated. The calculated quantum chemical parameters correlated to the inhibition efficiency are EHOMO (highest occupied molecular orbital energy), ELUMO (lowest unoccupied molecular orbital energy), the energy gap (ΔE) hardness (η), softness (S), dipole moment (μ), electron affinity (EA) ionization potential (IE), the absolute electro negativity (χ), and the fraction of electron transferred (ΔN). The decreasing order of %IE of the thiadiazolines studied was found to be in agreement with experimental corrosion inhibition efficiencies. The local reactivity has been analyzed through the condensed Fukui function and local softness indices using population analysis.

PENGGUNAAN FRONTIER ORBITAL MOLEKUL SEBAGAI DESKRIPTOR PADA ANALISIS HUBUNGAN KUANTITATIF STRUKTUR AKTIVITAS (HKSA) TOKSIK SENYAWA KHLOROFENOL

Quantitative structure-activity relationship (QSAR) methods have been applied to prediction of the toxicity of certain chemical compound. In this research a QSAR descriptor used frontier molecular orbital (LUMO energy (EL), HOMO energy (EH), and band gap (ΔE) and its derivatives were obtained from density functional theory (DFT) (chemical hardness (η) chemical potential (μ) or absolute electronegativity (χ) and global electrophicility indeks (ω)). Frontier molecular orbital (EL and EH) was calculated by ab initio quantum methods. This research found the correlation between the experimental ecotoxicological data of chlorophenols and toxicity prediction were calculated based on the best QSAR equation model of all equation model which have been studied. The best QSAR equation model using parameter LUMO energy (EL), and global electrophilicity index (ω) as descriptor on QSAR toxic of chlorophenol compounds against Bacilus sp TL81 is - log IC50 = 11,022 - 1,767 EL - 5,687 ω, and it has the coefficient of determination (R2) = 0,581 and standard deviation (SD) = 0,6111.