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دسترسی آزاد مقاله
1 - A conceptual framework chemistry of Hydrated Cations: Part I. Preliminary Ab Initio and QTAIM calculations on [Li(H20)nr (n=1,2,3).
Jamshid Najafpour Gholam Hossein Shafiee Abdolreza Sadjadi Shant ShahbazianIon molecules with general chemical formula as [Li(H2O)] (n=1,2,3), have been chosen as model species toinvestigate the chemical properties of hydrated lithium cations. The RHF(SCVS)/UGBS level of calculationhas been used for obtaining equilibrium geometries and Rho(r) چکیده کاملIon molecules with general chemical formula as [Li(H2O)] (n=1,2,3), have been chosen as model species toinvestigate the chemical properties of hydrated lithium cations. The RHF(SCVS)/UGBS level of calculationhas been used for obtaining equilibrium geometries and Rho(r) functions (electron density distributions). By theaid of fundamental physical theorems implemented in Quantum Theory of Atoms in Molecules (QTAIM), thestructures, the physical nature of chemical bonds and all atomic properties have been determined for citedspecies at the mentioned theoretical level. Then these atomic properties have been compared with theircorresponding values in isolated Li+ and H20 ingredients. Fragments of a molecule, Interaction andCoordination are the three fundamental concepts in this field, which have been fully discussed and redefinedunequivocally in a new context. پرونده مقاله -
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2 - Topological Analysis of Theoretical Charge Density of Alkali Metal Cations (LC, Na+, le)ICrown Ether (18e6) Complexes
J. Narafpour A. SadjadiThe DO1(18c6)fi (MwLi. Na. K and I 8c6=18-crown-6) complexes have been chosen as the model systems toinvestigate the nature of chemical bonds between alkali metal cations and large mffitidentaie orgmnic ligands.The B3LYP/6-3I+G(d,p) level of calculation has been used fo چکیده کاملThe DO1(18c6)fi (MwLi. Na. K and I 8c6=18-crown-6) complexes have been chosen as the model systems toinvestigate the nature of chemical bonds between alkali metal cations and large mffitidentaie orgmnic ligands.The B3LYP/6-3I+G(d,p) level of calculation has been used for obtaining equilibrium geernetnes and p(r)functions (electron density distributions). By the aid of fundamental physical theorems implemented inQuantum Theory of Atoms in Molecules (QTAINA), the structures and the physical nature of chemical bondshose been determined for cited species at the mentioned theoretical level. These results establish the metaloxygenin all complexes in this work as ionic. The Li+ shows the coordination number of 3 with Igen crownether and Na and rexhibits the coordination number of 6. پرونده مقاله -
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3 - Topological Analysis and Quantum Mechanical Structure of C4 and C5 Pure Carbon Clusters
Gholam Hossein Shafiee Jamshid Najafpour Seyed Abdolreza SadjadiTwo bonding models i.e cumullenic and acetylenic models have been proposed to account for thebonding patterns in linear carbon clusters while the bonding patterns in cyclic and 3D geometrieS of theseclusters have remained ambiguous.This work presents the bonding pattern چکیده کاملTwo bonding models i.e cumullenic and acetylenic models have been proposed to account for thebonding patterns in linear carbon clusters while the bonding patterns in cyclic and 3D geometrieS of theseclusters have remained ambiguous.This work presents the bonding patterns in various C4 and C5 pure clusters at MP2/aug-cc-pVTZ level oftheory. This subject is studied in the light of modern bonding theory known as Quantum Theory ofAtoms in Molecules, QTAIM.In linear clusters the ethylene like chemical bonds are reported, while in cyclic and 3D geometries thesingle and triple C-C bonds are found. پرونده مقاله -
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4 - QTAIM study of Bonding and Structure of Pure Atomic Clusters,Part III : Nn Clusters (n= 4,6)
Seyed Abdolreza Sadjadi Gholam Hossein Shafiee Amin EbadiDFT and QTAIM computations have been performed on numbers of pure nitrogen cluster speciesi.e. Nn (n = 4, 6) for investigating the structure and bonding. This study is critical since thesemolecules have been nominated as the good synthetic targets of High Energy Materia چکیده کاملDFT and QTAIM computations have been performed on numbers of pure nitrogen cluster speciesi.e. Nn (n = 4, 6) for investigating the structure and bonding. This study is critical since thesemolecules have been nominated as the good synthetic targets of High Energy Materials (HEM).0nthe other hand the decomposition mechanism is closely depends on the bonding pattern. Thislatter concept was searched via modem theory of Atoms in molecules (QTAIM) since theconventional methods were found to be incapable for describing the structure and bond in theseatomic clusters. پرونده مقاله -
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5 - X-ray Charge-Dens Study of 5-Chloro-8-hydroxy-6-methyloaphthalene-l.4-dione: A Hydroxynaphthoquinone Derivative
Zahra SharafiThe X-ray charge density analysis of a hydroxynaphthoquinnne derivative was obtained by multipolar Hansen-Coppens formalism refinement through high resolution X-ray diffraction data at 100(1) K. The molecularproperties of the title compound resulted from the combined ex چکیده کاملThe X-ray charge density analysis of a hydroxynaphthoquinnne derivative was obtained by multipolar Hansen-Coppens formalism refinement through high resolution X-ray diffraction data at 100(1) K. The molecularproperties of the title compound resulted from the combined experimental and the quantum theory of atoms inmolecules (QTAIM) studies. The topological properties of the covalent bonds and of the hydrogen bonds havebeen investigated. پرونده مقاله -
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6 - Electronic Properties of Hydrogen Adsorption on the Silicon- Substituted C20 Fullerenes: A Density Functional Theory Calculations
F. R. Nikmaram Jamshid NajafpourThe B3LYP/6-31++G** density functional calculations were used to obtain minimum geometries and interaction energies between the molecular hydrogen and nanostructures of fullerenes, C20 (cage), C20 (bowl), C19Si (bowl, penta), C19Si (bowl, hexa). The H2 molecule is set a چکیده کاملThe B3LYP/6-31++G** density functional calculations were used to obtain minimum geometries and interaction energies between the molecular hydrogen and nanostructures of fullerenes, C20 (cage), C20 (bowl), C19Si (bowl, penta), C19Si (bowl, hexa). The H2 molecule is set as adsorbed in the distance of 3Å at vertical position from surface above the pentagonal and hexagonal sites of nanostructures. By comparing of gap energies, electronic chemical potential, hardness and results of QTAIM (Quantum Theory of Atom in Molecules) analysis, the Si atom substitution in hexa two- fold position of C20 (bowl)may be suitable for the adsorption of hydrogen molecule. پرونده مقاله -
دسترسی آزاد مقاله
7 - Inductive Effect of Bioactive Intermolecular Hydrogen Bonding Complex of 1,2,4,5 –Tetrazine and Inorganic Acid by NMR and QTAIM
Mohammad Hossein Ghorbani Arash GhoorchianIn this paper, NMR and QTAIM analysis for three substituted of T2SA complex was investigated in the gas and four solvents at DFT level. Intermolecular O–H…N hydrogen bonds between 1,2,4,5-Tetrazine and Sulphurous acids enhance the stability of complex.1,2,4 چکیده کاملIn this paper, NMR and QTAIM analysis for three substituted of T2SA complex was investigated in the gas and four solvents at DFT level. Intermolecular O–H…N hydrogen bonds between 1,2,4,5-Tetrazine and Sulphurous acids enhance the stability of complex.1,2,4,5-Tetrazine is a highly reactive diene for [4+2] inverse-Diels–Alder cycloaddition processes and an excellent precursor to attain the pyridazine ring. 1,2,4,5-Tetrazines have been very widely utilized for the highly effective synthesis of natural products, bioactive compounds and ligands. The comparison between the donor and attractive group on hydrogen bonding intermolecular systems is discussed. The deshielding effects on hydrogen nucleus of this compound in solvents are referred to intermolecular hydrogen bonds which are controlled by dielectric constants. Dielectric constant increased the hydrogen atoms are deshielded, in the DMSO and water, the changes is small, because in theses polarity of solvent is very high. When donor group is substituted in this complex electron density is increased. The QTAIM results show that in the DMSO and water, the changes is small, because in theses polarity of solvent is very high. The NMR and QTAIM results are harmonious together in all cases. All calculations were performed using B3LYP method and 6-311++G** basis set in GAUSSIAN09W and AIM2000 programs. پرونده مقاله -
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8 - بررسی نظری ساختارهای چرخشی β دی پپتید محافظت شده سرین-آلانین با استفاده از محاسبات کوانتومی
بهزاد چهکندیدر این تحقیق با استفاده از محاسبات کوانتومی در فاز گازی در دو سطح محاسباتی B3LYP/6-311+G(d,p) و M06-2X/6-311+G(d,p)، ساختارهای چرخشی β فرم L دی پپتید محافظت شده سرین-آلانین بر روی نقشه راماچاندران مورد بررسی قرار گرفته اند. از بین 243 کنفورمر محتمل دی پپتید محافظت چکیده کاملدر این تحقیق با استفاده از محاسبات کوانتومی در فاز گازی در دو سطح محاسباتی B3LYP/6-311+G(d,p) و M06-2X/6-311+G(d,p)، ساختارهای چرخشی β فرم L دی پپتید محافظت شده سرین-آلانین بر روی نقشه راماچاندران مورد بررسی قرار گرفته اند. از بین 243 کنفورمر محتمل دی پپتید محافظت شده N-For-ser-ala-NH2، 26 کنفورمرساختار چرخشیβ را دارند. نظریه کوانتومی اتم ها در مولکول ها برای بررسی طبیعت پیوندهای هیدروژنی بین مولکولی ساختارهای چرخشی βمورد استفاده قرار گرفته است. نتایج بدست آمده مشخص می کنند که کنفورمر متعلق به نوع V ساختارهای βبه دلیل تشکیل سه پیوند هیدروژنی، پایدارترین ساختار چرخشیβ در بین همه ساختارها است. در حالی که ناپایدارترین ساختار چرخشیβ ( )، متعلق به نوع I، به ترتیب دو و یک پیوند هیدروژنی در دو سطح محاسباتی B3LYP/6-311+G(d,p) و M06-2X/6-311+G(d,p) را تشکیل می دهد. پرونده مقاله -
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9 - The electron density analysis of Cr(CO)3L complexes (L=benzene and graphyne)
Reza Ghiasi E Ardestanij J Motameni TabatabaiIn the present research, the electronic structure and bonding properties of the Cr(CO)3L complexes (L= 6-benzne, 6-garphyne) was studied with MPW1PW91 quantum chemical computations. Quantum theory of atoms in molecules (QTAIM) was applied to elucidate these complexes چکیده کاملIn the present research, the electronic structure and bonding properties of the Cr(CO)3L complexes (L= 6-benzne, 6-garphyne) was studied with MPW1PW91 quantum chemical computations. Quantum theory of atoms in molecules (QTAIM) was applied to elucidate these complexes Cr-CO bonds. The ellipticity () and values of the Cr-CO bonds were calculated. The amount of p-d back-donation of Cr-CO bonds were illustrated by calculation of the magnitude of the quadrupole polarization of carbon atom. Delocalization index values of C-C bonds of the six-member rings was calculated. Percentage composition in terms of the specified groups of frontier orbitals was found for these complexes to investigation of the feature in metal-ligand bonds. The nature of chemical bond between the -ring and Cr(CO)3 fragments was demonstrated through energy decomposition analysis (EDA). Frontier orbital analysis reveals that maximum contributions for HOMO and LUMO are the largest contribution of HOMO and LUMO arises from graphyne ligand in Cr(CO)3(6-graphyne) complex. EDA analysis reveals that interaction of benzene and Cr(CO)3 is stronger than graphyne with Cr(CO)3. Based on the results of the QTAIM analysis, there is a mixture of two parameters of the closed-shell and shared for Cr-CO bonds. The increase in quadrupole polarization values in the complexes compared to free CO values show the p-d back-donation in Cr-CO bonds. پرونده مقاله -
دسترسی آزاد مقاله
10 - Solvent influence on the interaction of cis-PtCl2(NH3)2 complex and graphene: A theoretical study
Elham Ebrahimi Mokarram Reza Fazaeli Hossein Aghaei Mohammad Yousefi Karim ZareIn this study the interaction of cis-PtCl2(NH3)2 complex and graphene were investigated with MPW1PW91method in gas and solvent phases. The solvent effect was examined by the self-consistent reaction fieldtheory (SCRF) based on Polarizable Continuum Model (PCM). The sele چکیده کاملIn this study the interaction of cis-PtCl2(NH3)2 complex and graphene were investigated with MPW1PW91method in gas and solvent phases. The solvent effect was examined by the self-consistent reaction fieldtheory (SCRF) based on Polarizable Continuum Model (PCM). The selected solvents were chloroform,chlorobenzene, bromoethane, dimethyldisulfide, and dichloroethane. The solvent effect on thefrontier orbital energy and HOMO-LUMO gap were studied. The characterization of the interactionbetween two fragments was clarified with energy decomposition analysis (EDA). Pt-C(Graphene) andH(NH3)...C(Garaphen) interactions in the graphene … cis-PtCl2(NH3)2 complex were analyzed usingquantum theory of atoms in molecules analysis (QTAIM). پرونده مقاله -
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11 - The electron density analysis of Cr(CO)3L complexes (L=benzene and graphyne)
Elham Ardestani Reza Ghiasi Javad Motameni Tabatabaih6-benzne, h6-garphyne) was studied with MPW1PW91 quantum chemical computations. Quantumtheory of atoms in molecules (QTAIM) was applied to elucidate these complexes Cr-CO bonds. Theellipticity (e) and h values of the Cr-CO bonds were calculated. The amount of pp-dp bac چکیده کاملh6-benzne, h6-garphyne) was studied with MPW1PW91 quantum chemical computations. Quantumtheory of atoms in molecules (QTAIM) was applied to elucidate these complexes Cr-CO bonds. Theellipticity (e) and h values of the Cr-CO bonds were calculated. The amount of pp-dp back-donation ofCr-CO bonds were illustrated by calculation of the magnitude of the quadrupole polarization of carbonatoms. Delocalization index values of C-C bonds of the six-member rings was calculated. Percentagecomposition in terms of the specified groups of frontier orbitals was found in these complexes to theinvestigation of the feature in metal-ligand bonds. The nature of chemical bond between the p-ring andCr(CO)3 fragments was demonstrated through energy decomposition analysis (EDA). پرونده مقاله -
دسترسی آزاد مقاله
12 - Dynamical distance as a semi-metric on nuclear configuration space
M. RahimiIn this paper, we introduce the concept of dynamical distance on a nuclear configuration space. We partition the nuclear conguration space into disjoint classes. This classification coincides with the classical partitioning of molecular systems via the concept ofconjuga چکیده کاملIn this paper, we introduce the concept of dynamical distance on a nuclear configuration space. We partition the nuclear conguration space into disjoint classes. This classification coincides with the classical partitioning of molecular systems via the concept ofconjugacy of dynamical systems. It gives a quantitative criterion to distinguish differentmolecular structures. پرونده مقاله
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