A theoretical study on the stereochemistry and protonation of −:CH2—NO2

1976 ◽  
Vol 54 (16) ◽  
pp. 2526-2533 ◽  
Author(s):  
P. G. Mezey ◽  
A. J. Kresge ◽  
I. G. Csizmadia
Keyword(s):  
Molecular Conformation ◽  
Theoretical Study ◽  
Negative Charge ◽  
Potential Surface ◽  
Population Analysis ◽  
Substantial Portion ◽  
Mulliken Population ◽  
Pyramidal Inversion ◽  
Pyramidal Configuration ◽  
A Charge

The molecular conformation of −:CH2NO2 is found to be planar with an extremely shallow potential curve to pyramidal inversion. This suggests that suitable substituents could conceivably perturb the System into a pyramidal configuration corresponding to double minimum on the potential surface and that a chiral carbanion might therefore exist. Rotating the NO2 group out of planarity by 90° raises the barrier to inversion at carbon by an appreciable amount.A Mulliken population analysis gives a charge distribution in which a substantial portion of the negative charge has shifted from carbon to oxygen; this is consistent with the well-known tendency of nitronate ions to undergo simultaneous competitive protonation on carbon and oxygen.

Molecular Calculations of Interplanar Electronic Interactions in a Ybacu2O6+δ Cluster as a Function of the Oxygen Concentration.

1990 ◽  
Vol 209 ◽  
Author(s):  
J. A. Cogordan ◽  
L. E. Sansores ◽  
A. A. Valladares
Keyword(s):  
Charge Transfer ◽  
Ab Initio ◽  
Population Analysis ◽  
Oxygen Stoichiometry ◽  
Mulliken Population Analysis ◽  
Mulliken Population ◽  
Electronic Interactions ◽  
A Charge ◽  
Molecular Calculations ◽  
Scf Calculations

ABSTRACTMolecular ab initio SCF calculations on a cluster formed by Y, Cu(2)-O(2)-O(3) plane, Ba-O(1) plane and Cu(1)-O(4) chains are reported. The computations were performed for five different sets of lattice parameters of YBACu2O6+δ Each of these sets correspond to a values of the oxygen stoichiometry. Mulliken population analysis results show a charge transfer to the Cu(2)-O(2)-O(3) plane when the oxygen stoichiometry is increased from six to seven.

TiO2/GRAPHENE OXIDE HETEROSTRUCTURES FOR GAS-SENSING: INTERACTION OF NITROGEN DIOXIDE WITH THE PRISTINE AND NITROGEN MODIFIED NANOSTRUCTURES INVESTIGATED BY DFT

2019 ◽  
Vol 26 (04) ◽  
pp. 1850170 ◽  
Author(s):  
AMIRALI ABBASI ◽  
JABER JAHANBIN SARDROODI
Keyword(s):  
Graphene Oxide ◽  
Charge Transfer ◽  
Density Of States ◽  
Density Functional ◽  
Gas Sensing ◽  
Population Analysis ◽  
Molecular Orbitals ◽  
Molecular Orbital Calculations ◽  
Mulliken Population ◽  
A Charge

The gas response of metal oxide-based sensors depends strongly on its adsorption properties. To explore the potential sensing capability of pristine and nitrogen modified TiO2/graphene oxide (GO) heterostructures, the adsorption of NO2 molecule on the N-doped nanocomposites was investigated using density functional theory (DFT) calculations. Six possible configurations were simulated based on the estimated adsorption energies. The binding sites were located over the oxygen, doped nitrogen and five-fold coordinated titanium atoms of TiO2. The electronic properties including atomic Mulliken population, projected density of states and molecular orbitals were investigated in detail. The N–O bonds of the NO2 molecule were significantly increased after the adsorption process. The adsorption of NO2 molecule on the N-doped nanocomposite is more energetically favorable than the adsorption on the undoped one. The results suggest that NO2 chemisorbs on the considered nanocomposites. Mulliken population analysis reveals a noticeable charge transfer from the nanocomposite to the molecule, which indicate that NO2 acts as a charge acceptor. Molecular orbital calculations show that the highest occupied molecular orbitals (HOMOs) of the studied systems were mainly localized on the adsorbed NO2 molecule. The significant overlaps in the projected density of states (PDOS) spectra of the interacting atoms confirm the formation of chemical bonds between them. There is a direct relationship between the results of charge transfer and sensing responses. N-doped nanocomposites have better sensing response than the undoped ones. The results highlight the possibility to develop innovative highly efficient NO2 sensors based on novel TiO2/GO nanocomposites.

scholarly journals A Theoretical Study of the Conformational Changes in Hydrazine

1974 ◽  
Vol 52 (15) ◽  
pp. 2785-2791 ◽  
Author(s):  
John O. Jarvie ◽  
Arvi Rauk
Keyword(s):  
Dihedral Angle ◽  
Conformational Changes ◽  
Theoretical Study ◽  
Potential Surface ◽  
Experimental Results ◽  
Hartree Fock ◽  
Pyramidal Inversion ◽  
Bond Functions ◽  
Torsional Component ◽  
Substituted Hydrazines

Abinitio restricted Hartree–Fock–Roothaan l.c.a.o.–m.o.–s.c.f. calculations using a Gaussian lobe basis with bond functions have been performed to determine the characteristics of the potential surface for nuclear motions in hydrazine. It was found that in its equilibrium conformation the molecule has a dihedral angle of 95°. The barrier to pyramidal inversion at one nitrogen is 6.1 kcal/mol and the syn and anti rotational barriers are calculated to be 12.0 and 1.6 kcal/mol, respectively. There is a very slight torsional component in the inversion pathway. During rotation over the anti barrier the bond angles contract from their average equilibrium value of 109.5° to 105.3°. This contraction appears to be an important feature of the rotational potential curve. Features of the surface are used to rationalize experimental results in cyclic and acyclic substituted hydrazines.

scholarly journals Ni Oxidation State and Ligand Saturation Impact on the Capability of Octaazamacrocyclic Complexes to Bind and Reduce CO2

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4139
Author(s):  
Barbora Vénosová ◽  
Ingrid Jelemenská ◽  
Jozef Kožíšek ◽  
Peter Rapta ◽  
Michal Zalibera ◽  
...  
Keyword(s):  
Quantum Theory ◽  
Oxidation State ◽  
Central Atom ◽  
Population Analysis ◽  
Mulliken Population Analysis ◽  
Mulliken Population ◽  
Theoretical Methods ◽  
Ni Oxidation ◽  
Shed Light

Two 15-membered octaazamacrocyclic nickel(II) complexes are investigated by theoretical methods to shed light on their affinity forwards binding and reducing CO2. In the first complex 1[NiIIL]0, the octaazamacrocyclic ligand is grossly unsaturated (π-conjugated), while in the second 1[NiIILH]2+ one, the macrocycle is saturated with hydrogens. One and two-electron reductions are described using Mulliken population analysis, quantum theory of atoms in molecules, localized orbitals, and domain averaged fermi holes, including the characterization of the Ni-CCO2 bond and the oxidation state of the central Ni atom. It was found that in the [NiLH] complex, the central atom is reduced to Ni0 and/or NiI and is thus able to bind CO2 via a single σ bond. In addition, the two-electron reduced 3[NiL]2− species also shows an affinity forwards CO2.

A gel-membrane model of glomerular charge and size selectivity in series

2001 ◽  
Vol 280 (3) ◽  
pp. F396-F405 ◽  
Author(s):  
Maria Ohlson ◽  
Jenny Sörensson ◽  
Börje Haraldsson
Keyword(s):  
Negative Charge ◽  
Careful Analysis ◽  
Size Selectivity ◽  
Gel Structure ◽  
Experimental Conditions ◽  
Ion Interactions ◽  
In Series ◽  
A Charge ◽  
Glomerular Barrier

We have analyzed glomerular sieving data from humans, rats in vivo, and from isolated perfused rat kidneys (IPK) and present a unifying hypothesis that seems to resolve most of the conflicting results that exist in the literature. Particularly important are the data obtained in the cooled IPK, because they allow a variety of experimental conditions for careful analysis of the glomerular barrier; conditions that never can be obtained in vivo. The data strongly support the classic concept of a negative charge barrier, but separate components seem to be responsible for charge and size selectivity. The new model is composed of a dynamic gel and a more static membrane layer. First, the charged gel structure close to the blood compartment has a charge density of 35–45 meq/l, reducing the concentration of albumin to 5–10% of that in plasma, due to ion-ion interactions. Second, the size-selective structure has numerous functional small pores (radius 45–50 Å) and far less frequent large pores (radius 75–115 Å), the latter accounting for 1% of the total hydraulic conductance. Both structures are required for the maintenance of an intact glomerular barrier.

scholarly journals Effect of Doping on the Photoelectric Properties of Borophene

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Chunhong Zhang ◽  
Zhongzheng Zhang ◽  
Wanjun Yan ◽  
Xinmao Qin
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Population Analysis ◽  
Covalent Bond ◽  
Infrared Light ◽  
Chemical Bonds ◽  
Mulliken Population Analysis ◽  
Mulliken Population ◽  
Photoelectric Properties ◽  
Effect Of Doping

Borophene is a new type of two-dimensional material with a series of unique and diversified properties. However, most of the research is still in its infancy and has not been studied in depth. Especially in the field of semiconductor optoelectronics, there is no related research on the modulation of photoelectric properties of borophene. In this work, we focus on the effect of doping on the photoelectric properties of borophene by using the first-principles pseudopotential plane wave method. We calculate the geometric structure, electronic structure, Mulliken population analysis, and optical properties of impurity (X = Al, Ga) doped α-sheet borophene. The results show that α-sheet borophene is an indirect band gap semiconductor with 1.396 eV. The band gap becomes wider after Al and Ga doping, and the band gap values are 1.437 eV and 1.422 eV, respectively. Due to the orbital hybridization between a small number of Al-3p electrons and Ga-4p state electrons and a large number of B 2p state electrons near the Fermi level, the band gap of borophene changes and the peak value of the electron density of states reduces after doping. Mulliken population analysis shows that the B0-B bond is mainly covalent bond, but there is also a small amount of ionic bond. However, when the impurity X is doped, the charge transfer between X and B atoms increases significantly, and the population of the corresponding X-B bonds decreases, indicating that the covalent bond strength of the chemical bonds in the doped system is weakened, and the chemical bonds have significant directionality. The calculation of optical properties shows that the static dielectric constant of the borophene material increases, and the appearance of a new dielectric peak indicates that the doping of Al and Ga can enhance the ability of borophene to store electromagnetic energy. After doping, the peak reflectivity decreases and the static refractive index n0 increases, which also fills the gap in the absorption of red light and infrared light by borophene materials. The research results provide a basis for the development of borophene materials in the field of infrared detection devices. The above results indicate that doping can modulate the photoelectric properties of α-sheet borophene.

scholarly journals Novel Insights into the Hydroxylation Behaviors of α-Quartz (101) Surface and its Effects on the Adsorption of Sodium Oleate

Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 450 ◽  
Author(s):  
Zhang ◽  
Xu ◽  
Hu ◽  
He ◽  
Tian ◽  
...  
Keyword(s):  
Sodium Oleate ◽  
Density Functional ◽  
Population Analysis ◽  
Water Molecules ◽  
Mulliken Population ◽  
Flotation Reagents ◽  
Functional Theory ◽  
Rigorous Study ◽  
Adsorption Energies ◽  
Hydroxylated Surface

A scientific and rigorous study on the adsorption behavior and molecular mechanism of collector sodium oleate (NaOL) on a Ca2+-activated hydroxylated α-quartz surface was performed through experiments and density functional theory (DFT) simulations. The rarely reported hydroxylation behaviors of water molecules on the α-quartz (101) surface were first innovatively and systematically studied by DFT calculations. Both experimental and computational results consistently demonstrated that the adsorbed calcium species onto the hydroxylated structure can significantly enhance the adsorption of oleate ions, resulting in a higher quartz recovery. The calculated adsorption energies confirmed that the adsorbed hydrated Ca2+ in the form of Ca(H2O)3(OH)+ can greatly promote the adsorption of OL− on hydroxylated quartz (101). In addition, Mulliken population analysis together with electron density difference analysis intuitively illustrated the process of electron transfer and the Ca-bridge phenomenon between the hydroxylated surface and OL− ions. This work may offer new insights into the interaction mechanisms existing among oxidized minerals, aqueous medium, and flotation reagents.

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