Ab-initio and DFT calculations on molecular structure, NBO, HOMO–LUMO study and a new vibrational analysis of 4-(Dimethylamino) Benzaldehyde

Rocha, Mariana; Santo, Alfredo Alejandro Di; Arias, Juan Marcelo; Gil, Diego M.; Altabef, A. Ben

doi:10.1016/j.saa.2014.09.077

Cited by 81 publications

(37 citation statements)

References 36 publications

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“…The HOMO represents the ability to donate an electron, whereas the LUMO, as an electron acceptor, represents the ability to gain an electron. The energy gap between the HOMO and LUMO determines the energy that is very important to calculate the activation parameters, and it can be used to describe further the chemical reactivity of the title compound and its precursor starting tautomer, as it is already known that the HOMO–LUMO energy gap (Δ E ) is an important stability index . As given in Table S4, the calculated electronic parameters, namely, ionization potential (IP), electron affinity (EA), hardness ( η ), and softness ( σ ), were calculated for the thione and thiol forms of the starting material and target product 2 in chloroform, ethanol, and acetonitrile.…”

Section: Resultsmentioning

confidence: 99%

“…The energy gap between theH OMO and LUMO determines the energy that is very important to calculate the activation parameters, [33,34] and it can be used to describe furthert he chemicalr eactivity of the title compound and its precursors tartingt automer,a si ti s already known that the HOMO-LUMO energy gap (DE)i sa n important stabilityindex. [35][36][37] As given in Ta ble S4, the calculated electronic parameters,namely,i onization potential(IP), electron affinity (EA), hardness (h), and softness (s), were calculated for the thione and thiol forms of the startingm ateriala nd targetp roduct 2 in chloroform, ethanol, and acetonitrile. The IP and EA values were calculated as the negative energy eigen valueso ft he HOMO and LUMO, respectively.C hemical hardness [38,39] was calculated according to Equation ( The calculated values of thesee lectronic parameters (Table S4)t ogetherw ith the resultso ft he dipole moment values previously obtained (Table S1) confirmed that the polarity of the solvents played an important role in the reactivity and stabilityo ft he molecules (dipolem oment of the thione form in the gas phase was found to be greater than that of the thiol form and increased upon increasing the dielectric constanto ft he solvent used).…”

Section: Frontier Molecularorbitals and Reactivityp Arametersmentioning

confidence: 99%

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Synthesis, Spectroscopic Characterization, and Time‐Dependent DFT Calculations of 1‐Methyl‐5‐phenyl‐5H‐pyrido[1,2‐a]quinazoline‐3,6‐dione and Its Starting Precursor in Different Solvents

Hamada

2018

ChemistryOpen

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In this study, 2‐mercapto‐3‐phenyl‐2,3‐dihydro‐1H‐quinazolin‐4‐one (1), which exists as a thiol and thione tautomer, was treated with acetylacetone to give the target compound, namely, 1‐methyl‐5‐phenyl‐5H‐pyrido[1,2‐a]quinazoline‐3,6‐dione (2). The spectroscopic data, including UV/Vis, IR, 1H NMR, 13C NMR, and mass data, of this compound were recorded. The molecular structures of the starting material (1) and the product (2) were optimized by using density functional theory (DFT) by employing the B3LYP exchange correlation with the 6‐311G (d, p) and 6‐31G++ (d, p) basis sets. The electronic spectra were determined based on time‐dependent DFT calculations in three different solvents (i.e., chloroform, ethanol, and acetonitrile) starting from the same solvated run of the optimized geometry with the same two basis sets. The solvent effects were considered based on the polarizable continuum model (PCM), and the energetic behavior of the compounds and the total static dipole moment (μ) in different solvents were examined in the two basis sets; the results showed that the total energy of the compounds decreased upon increasing the polarity of the solvent. Time‐dependent DFT calculations were performed to analyze the electronic transitions for various excited states that reproduced the experimental band observed in the UV/Vis spectrum. A study on the electronic properties, such as the HOMO and LUMO energies, was performed by the time‐independent DFT approach. Using the gauge‐independent atomic orbital method (GIAO), the 1H NMR chemical shifts were calculated and correlated with the experimental ones. The computed results showed that the introduction of different dielectric media had a slight effect on the stability and reactivity of the title compound as well as on the Milliken atomic charges and the molecular geometry. Besides, the molecular electrostatic potential of target product 2 was evaluated in different solvents.

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Section: Resultsmentioning

confidence: 99%

Section: Frontier Molecularorbitals and Reactivityp Arametersmentioning

confidence: 99%

Synthesis, Spectroscopic Characterization, and Time‐Dependent DFT Calculations of 1‐Methyl‐5‐phenyl‐5H‐pyrido[1,2‐a]quinazoline‐3,6‐dione and Its Starting Precursor in Different Solvents

Hamada

2018

ChemistryOpen

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“…Recently, Koopman's theory has been used to calculate ionization potential for different compounds by Chong et al(Chong et al, 2002) using orbital energies which is equal to a negative value of HOMO energy (IP =-E HOMO ). A negative value of LUMO energy is equal to electron affinity (EA = -E LUMO ) (Shankar et al, 2009, Rocha et al, 2015. The chemical hardness η of the molecule based on the molecular orbital can be calculated by the following equation (equation 1) (Galván et al, 2015) η ( ) Equation 1…”

Section: Frontier Molecular Orbital (Fmo) Analysismentioning

confidence: 99%

“…Therefore, Other chemical properties can be calculated by using LUMO and HOMO energy values for instance; hardness η = IP-EA/2, electrophilicity index ω = μ 2 /2η, electronegativity χ = IP+EA/2, chemical potential μ=-χ, , softness s = 1/2η and. (Rocha et al, 2015) (Table 2) Table 2 shows small values of E LUMO-HOMO gap indicating a soft molecule, more reactive, and higher polarizable compound than high values of ELUMO-HOMO . Values also show that the compound can easily decompose spontaneously to its elements.…”

Section: Equationmentioning

confidence: 99%

Computational study of optical properties, and enantioselective synthesis of di-substituted esters of hydantoic and thiohydantoic acids

2020

ZJPAS

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The title compounds with different optically active substituted ester of hydantoic and thiohydantoic were synthesized by the reaction of corresponding enantio-pure amino acids methyl ester hydrochloride with phenylisocyanate/thiocyanate in the presence of triethylamine. The duration of reaction was limited to avoid racemisation and produce high enantio-enriched compounds. Low values of ELUMO-HOMO gap 0.14, 0.16, 0.15, 0.15, and 0.10 eV were observed for compounds 1, 2, 3, 4, and 5, respectively indicate soft, and high reactivity compounds. Values of ELUMO-HOMO gap also show that the compounds can easily decompose spontaneously to their elements. The order of synthesized compounds based on increasing reactivity depends on LUMO-HOMO energy gap represent as follows; 5>1>3, 4>2. Thermodynamic energies have been calculated for synthesized compounds including Enthalpy and Gibbs free energy.

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“…Zinc and copper-containing phthalic acid derivatives may also be used as sensors or catalyst support (Detsri and Seeharaj, 2017). The theoretical chemical calculations of DFT B3LYP have been studied well and consistently (Cabir et al, 2020;Prabhaharan et al, 2015;Priya et al, 2019;Rocha et al, 2015). Theoretical studies have been used in many studies on organo metal compounds (El Bourakadi et al, 2019;Kumar et al, 2019;Pandey et al, 2017;Solğun et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Preparation of Metal Complexes of 4,5-Dichlorphthalic Acid as Nanoscale and Electronic Properties

Keskin

Yıldıko

Solğun

et al. 2020

Iğdır Üniversitesi Fen Bilimleri Enstitüsü Dergisi

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Here phthalic acid metal complexes with acid function were synthesized. Fourie transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), Scanning electron microscopy-Energy Dispersive Spectrometry (SEM+EDS) devices were used for structure analysis. The structural parameters of the copper and zinc complexes of 4,5-dichlorphthalic acid were determined by the LanL2DZ basis base set of B3LYP method. Electronic properties such as HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energies and molecular electrostatic potential (MEP) were obtained. Stability, charge delocalization of molecules resulting from hyperconjugative interactions were analyzed using natural bond orbital (NBO) analysis. The comparison of the theoretical and experimental FT-IR spectra of Zn and Cu-4,5-dichlorphthalic acid (DCPA) were made and R = 0.97204 for Cu and R = 0.97929 for Zn complex were found in linear fit studies. Two characterization results were found to be consistent.

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Ab-initio and DFT calculations on molecular structure, NBO, HOMO–LUMO study and a new vibrational analysis of 4-(Dimethylamino) Benzaldehyde

Cited by 81 publications

References 36 publications

Synthesis, Spectroscopic Characterization, and Time‐Dependent DFT Calculations of 1‐Methyl‐5‐phenyl‐5H‐pyrido[1,2‐a]quinazoline‐3,6‐dione and Its Starting Precursor in Different Solvents

Synthesis, Spectroscopic Characterization, and Time‐Dependent DFT Calculations of 1‐Methyl‐5‐phenyl‐5H‐pyrido[1,2‐a]quinazoline‐3,6‐dione and Its Starting Precursor in Different Solvents

Computational study of optical properties, and enantioselective synthesis of di-substituted esters of hydantoic and thiohydantoic acids

Preparation of Metal Complexes of 4,5-Dichlorphthalic Acid as Nanoscale and Electronic Properties

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