Stereoelectronic effects of porphyrin ligand on the oxygen transfer efficiency of high valent manganese-oxo porphyrin species: A DFT study

2015 ◽  
Vol 19 (10) ◽  
pp. 1130-1139 ◽  
Author(s):  
Hossein Kavousi ◽  
Heidar Raissi ◽  
Abdolreza Rezaeifard ◽  
Maasoumeh Jafarpour
Keyword(s):  
Density Functional ◽  
Chemical Potential ◽  
Water Solution ◽  
Dft Method ◽  
Nbo Analysis ◽  
Basis Set ◽  
Chemical Hardness ◽  
Third Generation ◽  
Oxygen Transfer Efficiency ◽  
High Valent

The structure and properties of the N[Formula: see text]–Mn–O bonds of high valent manganese-oxo of the second and third generation porphyrins in the presence of imidazole have been studied by means of density functional (DFT) method with 6-31G* basis set in the gas phase as well as water solution. The geometric structures, frontier molecular orbitals, thermodynamic parameters, aromaticity indices and physical properties such as chemical potential and chemical hardness of [(TPP)(ImH)MnO][Formula: see text] and its derivatives were calculated. The obtained results showed that [(TPP)(ImH)MnO][Formula: see text] bearing halogen atoms at the [Formula: see text]-pyrrole positions had a saddle conformation with low Mn–O strength. The electron density ([Formula: see text] and Laplacian ([Formula: see text] properties at critical points of the N[Formula: see text]–Mn–O bonds, estimated by AIM calculations, indicate that Mn–O bonds in third generation porphyrins have lower [Formula: see text] and Mn–N[Formula: see text] distances have higher [Formula: see text] than the second generation ones. The calculations of aromaticity indices for chelated rings at the porphyrin center show that HOMA and NICS in third generation porphyrins are generally lower than that of second ones which is in agreement with their saddle conformation. These results are supported by natural bond orbital (NBO) analysis.

A DFT investigation of axial N-donor ligands effects on the high valent manganese-oxo meso-tetraphenyl porphyrin

2015 ◽  
Vol 19 (05) ◽  
pp. 651-662 ◽  
Author(s):  
Hossein Kavousi ◽  
Abdolreza Rezaeifard ◽  
Heidar Raissi ◽  
Maasoumeh Jafarpour
Keyword(s):  
Density Functional ◽  
Chemical Potential ◽  
Water Solution ◽  
Nbo Analysis ◽  
Basis Set ◽  
Donor Ligands ◽  
Chemical Hardness ◽  
B3lyp Method ◽  
Nitrogen Donors ◽  
High Valent

The effect of different electronic and structural nitrogen donors (L) on the N ( ax )- Mn - O properties in the high valent manganese-oxo meso-tetraphenylporphyrin intermediate is investigated by the density functional B3LYP method with 6-31g* basis set. The geometric structures, frontier molecular orbitals, thermodynamic parameters and physical properties such as chemical potential and chemical hardness of [( TPP )( L ) MnO ]+ complexes in the gas phase as well as water solution are calculated. Our theoretical results confirm that the Mn - O distances in [( TPP )( L ) MnO ]+ species decrease by replacing imidazoles with pyridines, amins as well as electron-poor and hindered nitrogen donors resulting from extending the Mn – N ( ax ) bonds. These results are supported by vibrational frequencies, atoms in molecules (AIM) and natural bond orbital (NBO) analysis. It is worth mentioning that the co-catalytic activity trend of different nitrogen donors observed experimentally in the presence of title Mn porphyrin is consistent with the calculated Mn – N ( ax ) and Mn – O bond lengths in this work.

Spectroscopic and DFT studies of 2,4-dichloro-N-phenethylbenzenesulfonamide

2020 ◽  
Vol 5 (6) ◽  
Author(s):  
R. Kavipriya ◽  
Helen P. Kavitha ◽  
Jasmine P. Vennila ◽  
Lydia Rhyman ◽  
Ponnadurai Ramasami
Keyword(s):  
Density Functional ◽  
Chemical Potential ◽  
Dft Method ◽  
Electronic Energy ◽  
Basis Set ◽  
Chemical Hardness ◽  
Charge Delocalization ◽  
Hartree Fock ◽  
Nlo Property ◽  
The Fourier Transform

AbstractThe Fourier-transform infrared spectroscopy (FT-IR) spectrum of 2,4-dichloro-N-phenethylbenzenesulfonamide (DPBS) was obtained and the compound was studied theoretically. The optimized geometry, total electronic energy and vibrational wavenumbers of DPBS were examined using Hartree–Fock (HF) and density functional theory (DFT) method such as B3LYP, BP86 and M06 functionals with the basis set of 6-311++G(d,p) for all atoms. A complete vibrational assignment was studied for DPBS. The molecular orbital energies, polarizability and thermodynamic properties of DPBS were also computed. Analysis of molecular orbitals reveals the parameters such as chemical potential, chemical hardness and electrophilicity index. The molecular properties such as electric dipole moment µ, polarizability α, and hyperpolarizability β reveal the non-linear optical (NLO) property of DPBS. Natural bond analysis study reveals charge delocalization of the molecule. The experimental and computational results are found to have good agreement among themselves. The results of this work will pave the way for further insight in the study of the applications of DPBS.Graphical Abstract:

2,4-Dimorpholino-4-yl-6-(4-nitrophenoxy)-[1,3,5]-triazine: Structural and spectroscopic study using experimental and DFT method

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
R. Kavipriya ◽  
Helen P. Kavitha ◽  
B. Karthikeyan ◽  
Jasmine P. Vennila ◽  
Lydia Rhyman ◽  
...  
Keyword(s):  
Density Functional ◽  
Chemical Potential ◽  
Structural Parameters ◽  
Dft Method ◽  
Vibrational Frequencies ◽  
Basis Set ◽  
Chemical Hardness ◽  
Charge Delocalization ◽  
The Fourier Transform ◽  
Molecular Orbital Analysis

Abstract2,4-Dimorpholino-4-yl-6-(4-nitrophenoxy)-[1,3,5]-triazine (DMNT) was synthesized and the molecular structure and vibrational frequencies were studied by density functional theory (DFT) method. The functional used was Becke’s three parameter exchange functional combined with the Lee-Yang-Parr correlation (B3LYP) and the standard basis set was 6-31G(d) for all atoms. The Fourier Transform-Infra Red (FT-IR) and FT-Raman spectra of DMNT were recorded and complete assignments of the observed vibrational frequencies are done. The assignments were confirmed by isotopic labelling. The structural parameters, harmonic vibrational frequencies, IR intensities and Raman intensities of DMNT in the ground-state were also computed. Non-linear optical behaviour of DMNT was analysed by examining the properties like electric dipole moment, polarizability and hyperpolarizability. Molecular properties such as ionization potential, electro-negativity, chemical potential and chemical hardness were obtained from molecular orbital analysis. Hyper conjugative interaction and charge delocalization taking place in DMNT was confirmed by Natural bond analysis studies. UV-Vis spectrum of DMNT was also recorded to understand the electronic properties.Graphical Abstract:

scholarly journals Catalytic effect of TMCmHm  compounds on the reaction rate of  " Hydrazin - Oxygen "fuel cell  "TM = Cr, Sc, Ti, V and m= 4 or 5" A DFT Study ​

2021 ◽  
Author(s):  
Zohreh Mohammadi Ahmad Mahmodi ◽  
Mehran Aghaie ◽  
Maziar Noei ◽  
Hossein Aghaie
Keyword(s):  
Fuel Cell ◽  
Molecular Orbital ◽  
Density Functional ◽  
Reaction Rate ◽  
Chemical Potential ◽  
Organometallic Compounds ◽  
Basis Set ◽  
Optimal Structure ◽  
Chemical Hardness ◽  
Oxygen Fuel

Abstract Platinum and similar metals are suitable catalysts in response to fuel cells, however, because of being costly, their use is limited. So in this study, the catalytic efficiency of some organometallic compounds with the general formula TMCmHm on the reaction rate of "Hydrazine- Oxygen "fuel cell was studied via density Functional Theory (DFT). To perform the respect calculations, the PW91 method and 6-31 G(d) basis set were used. Bonds’ length of O=O and N-N increased in response to their adsorption onto TMCmHm and theoretical study of N2H4-O2 fuel cell the partial transfer of negative charge from organometallic compounds to their π * orbitals. Bond length of O=O increased by 24% due to its adsorption on ScC5H5 and N-N on ScC5H5 increased by 11%. The optimal structure of each studied organometallic compound was plotted by performing natural bond orbital calculations (NBO). The energy of the highest occupied molecular orbital (EHOMO) and the lowest unoccupied molecular orbital (ELUMO) were calculated. Besides, , the gap energies (Eg), chemical hardness (ɳ), chemical potential (µ), and electrophilicity (ω) were calculated in each case. Then, the optimal structure of O2/TMCmHm and N2H4/ TMCmHm pairs was plotted; the adsorption energy of O2 and N2H4 on each of TMCmHm was evaluated. The kinetic adsorption of O2 and N2H4 on the Sc C5H5 compound was investigated by the 6-31 G * method. The potential energy of O2/TMCmHm and N2H4/ TMCmHm pairs in the initial and final position and the transient state were estimated, and the respect kinetic parameters were calculated.

Studies of intramolecular H-bond interactions and solvent effects in the conformers of glycolic acid — A quantum chemical study

2018 ◽  
Vol 17 (01) ◽  
pp. 1850009 ◽  
Author(s):  
Mahendiraprabu Ganesan ◽  
Nirmala Vedamanickam ◽  
Selvarengan Paranthaman
Keyword(s):  
Solvent Effects ◽  
Density Functional ◽  
Glycolic Acid ◽  
Chemical Potential ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
Basis Set ◽  
Chemical Hardness ◽  
Geometrical Parameters ◽  
Water Media

In this work, density functional theory is applied to understand the conformational stability and solvent effects on glycolic acid conformers in different solvents. In addition, the role of intramolecular hydrogen bond (H-bond) interactions in the stability of conformers are investigated. The molecular geometries of selected conformers are optimized using B3LYP and PBE0 functionals with 6-311[Formula: see text]G(d,p) basis set. The effects of solvent on the geometrical parameters, relative stability, dipole moment, chemical hardness, chemical potential, etc. are studied for the conformers of glycolic acid. Our calculations show that the order of stability of the SSC and AAT conformers does not change in liquid phase. However, the energy of SSC and AAT conformers is very close to each other in water media. In water media, strong intramolecular H-bond interaction is present in AAT conformer which causes the energy of AAT conformer to be very close to that of SSC conformer. This may be due to the influence of water media.

scholarly journals Therortical Studies and Investagting of Selected Potnet CDK2 Inhibitors as Anticancer Agents

2021 ◽  
Author(s):  
Mohammad J Abunuwar ◽  
Adnan A Dahadha
Keyword(s):  
Anticancer Agents ◽  
Density Functional ◽  
Chemical Potential ◽  
Chemical Reactivity ◽  
Three Dimensional ◽  
Data Bank ◽  
Basis Set ◽  
Chemical Hardness ◽  
Cyclin Dependent Kinase ◽  
Reactivity Descriptors

Abstract In this study eight selected of the most potent cyclin dependent kinase 2 inhibitors in which targeting adenosine triphosphate -pocket site theoretically investigated to support literature information of frontier molecular orbitals, molecular electrostatic maps, and global chemical reactivity descriptors such as chemical hardness, chemical softness, chemical potential, electronegativity and electrophilicity of cyclin dependent kinase 2 inhibitors. Calculation and three-dimensional plotting were achieved through Gaussian 09W and Gausview 6 software’s utilizing density functional theory quantum modeling applying both hybrids extended and not extended basis set. Crystal structure of CDK2 with inhibitors was obtained from protein data bank and visualized through PyMol Schrödinger software to assign polar and non-polar interactions of inhibitors with enzyme. A promising conclusion trend obtained in this research regarding to molecules that could have an inhibition activity toward the cyclin dependent kinase 2 enzymes. Our theoretical investigation emphasizes that, the anti-cancer activity has directly relationship with value of chemical hardness and chemical softness, where the most potent compounds was the pyrazolopyrimidine and imidazole pyrimidine and they have higher chemical hardness value and at the same time lower value of chemical softness compared with the rest of compounds.

Combined experimental and theoretical studies on 4-(2-hydroxy-3-morpholin-4-yl-propoxy)-chromen-2-one

2016 ◽  
Vol 15 (02) ◽  
pp. 1650017
Author(s):  
Priyanka ◽  
Sanjay Kumar Srivastava ◽  
Diksha Katiyar
Keyword(s):  
Density Functional ◽  
Chemical Potential ◽  
Chemical Shifts ◽  
Basis Set ◽  
Chemical Hardness ◽  
Functional Theory ◽  
Reactivity Descriptors ◽  
Hartree Fock ◽  
Homo And Lumo ◽  
Experimental And Theoretical Studies

The FTIR, UV–Vis and NMR spectra of 4-(2-hydroxy-3-morpholin-4-yl-propoxy)-chromen-2-one (4-HMPC) have been recorded and analyzed. The optimized geometry and harmonic vibrational frequencies of 4-HMPC were obtained by the Hartree–Fock (HF) and density functional theory (DFT) using B3LYP functional with 6-311[Formula: see text]G basis set. The 1H and [Formula: see text]C NMR chemical shifts were calculated by the GIAO method in chloroform. The absorption spectra of 4-HMPC were computed in ethanol and water solutions using TD-B3LYP/6-311[Formula: see text]G(d,p) approach. The correlation of theoretical and experimental results provides a detailed description of the structural and physicochemical properties of the molecule. The results obtained from the studies of HOMO and LUMO were used to calculate the conceptual-DFT-based global reactivity descriptors such as electronic chemical potential, electronegativity, chemical hardness, global softness and electrophilicity index of the compound.

scholarly journals Synthesis, Spectroscopic Studies, Antimicrobial Activity and Computational Calculations on 3-Nitroanilinium Dihydrogen Phosphate

2021 ◽  
Vol 33 (5) ◽  
pp. 1099-1106
Author(s):  
Subramanian Thangarasu ◽  
Vadivel Siva ◽  
Shunmuganarayanan Athimoolam ◽  
Sultan Asath Bahadur
Keyword(s):  
Antimicrobial Activity ◽  
Density Functional ◽  
Chemical Potential ◽  
Basis Set ◽  
Experimental Result ◽  
Frontier Molecular Orbital ◽  
Chemical Hardness ◽  
Geometrical Parameters ◽  
Dihydrogen Phosphate ◽  
Computational Calculations

3-Nitroanilinium dihydrogen phosphate (3NADP) has been synthesized and crystallized successfully using the method of solvent evaporation solution growth. The molecular structure has been optimized and geometrical parameters of 3NADP also have been analyzed using B3LYP function with density functional theory (DFT) and Hartree-Fock (HF) methods with a 6-311++G(d,p) basis set. The comparison between computed vibrational spectra and experimental result shows an appreciable agreement. The thermal stability of 3NADP crystal was analyzed using TG/DTA and the melting point was identified at 209 ºC. The properties like electronegativity, chemical hardness, electrophilicity index and chemical potential of the crystal were determined through HOMO-LUMO study. Lower band gap value obtained in frontier molecular orbital analysis and favours the possible biological activity of 3NADP. The grown crystals was also screened for the antimicrobial activity against some specific potentially threatening microbes.

Structural, QTAIM, thermodynamic properties, bonding, aromaticity and NMR analyses of cation–π interactions of mono and divalent metal cations (Li+, Na+, K+, Be2+, Mg2+, and Ca2+) with substituted pyrazine derivatives

2015 ◽  
Vol 14 (06) ◽  
pp. 1550044 ◽  
Author(s):  
Maryam Zaboli ◽  
Heidar Raissi
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Chemical Potential ◽  
Basis Set ◽  
Chemical Hardness ◽  
Aromatic Rings ◽  
Functional Theory ◽  
Highest Occupied Molecular Orbital ◽  
Polarized Continuum Model ◽  
Lowest Unoccupied Molecular Orbital

Theoretical investigation of 42 cation-π complexes formed by the alkali metal ( Li +, Na +, K +), alkaline-earth cations ( Be 2+, Mg 2+, Ca 2+) and π-system of the pyrazine and its derivatives have been performed at density functional theory (DFT) (B3LYP functional) and MP2 methods with 6-311++G** basis set in the gas phase and the polarized continuum model (PCM)-water solvation. The following substituents have been taken into consideration: Br , Cl , CH 3, OH , OCH 3 and SH . The interactions present in these complexes have been investigated by means of the natural bond orbital (NBO) and the Bader's quantum theory of atoms in molecules (QTAIMs) approaches. The effects of the interactions on NMR data have been probed using the GIAO-based method to extend investigation of the studied compounds. The calculated highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies show that charge transfer occurs within each complex. Vibrational frequencies and physical properties such as dipole moment, chemical potential, chemical hardness and chemical electrophilicity of these compounds have been systematically explored. The aromaticity of aromatic rings has been measured using several well-established indices of aromaticity such as nucleus-independent chemical shift, harmonic oscillator models of the aromaticity, para-delocalization index, average two-center indices, aromatic fluctuation index and π-fluctuation aromatic index.

INFLUENCE OF CATION-HETEROATOM (Li+, Na+, AND K+) INTERACTION ON THE STRUCTURAL AND THERMOCHEMICAL PROPERTIES OF 2′-DEOXYTHYMIDINE NUCLEOSIDE: QTAIM AND NBO ANALYZES

2013 ◽  
Vol 12 (02) ◽  
pp. 1250113 ◽  
Author(s):  
MEHDI SHAKOURIAN-FARD ◽  
ALIREZA FATTAHI
Keyword(s):  
Metal Ion ◽  
Density Functional ◽  
Natural Bond Orbital ◽  
Population Analysis ◽  
Dft Method ◽  
Closed Shell ◽  
Nbo Analysis ◽  
Basis Set ◽  
Functional Theory ◽  
Sugar Ring

Density functional theory (DFT) method and B3LYP/6-311++G(d,p) basis set were used to determine coordination geometries, binding strength, and metal ion affinity (MIA) for interaction of 2′-deoxythymidine (dT) with alkali metal cations including Li+, Na+ , and K+ . Calculations demonstrated that the interaction of dT with these cations is tri-coordinated η (O2, O4′, O5′). Among these cations, Li+ cation exhibited the most tendency for interaction with dT. Cations via their interaction with dT can affect the N-glycosidic bond length, the values of pseudorotation of the sugar ring, the orientation of base unit with respect to sugar ring and the acidity of O5′H, O3′H, and N3H groups in 2′-dT nucleoside. Natural bond orbital (NBO) analysis was performed to calculate the charge transfer and natural population analysis of the complexes. Quantum theory of atoms in molecules (QTAIM) was also applied to determine the nature of interactions. It was shown that in these complexes, (dT- Li+ , dT- Na+ , and dT- K+ ), the bonds are an electrostatic (closed-shell) interaction in the nature.

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