نتایج جستجو برای: nucleus independent chemical nics

تعداد نتایج: 917632  

F. Naderi M. Anafche

The structural stabilities, geometry and electronic properties of C24 and some its heterofullerenederivatives are compared at the B3LYP/6-311-EFG**//B3LYP/6-31+G* level of theory. Vibrationalfrequency calculations show that all the systems are true minima. The calculated binding energies ofheterofullerenes show C24 as the, most stable fullerenes by 9.03eV/atom. While decreasing bindingenergy in...

2015
J. Oscar C. Jimenez-Halla Eduard Matito Miquel Solà Holger Braunschweig Christian Hörl Ivo Krummenacher Johannes Wahler

In this contribution, we have evaluated the (anti)aromatic character of thirty-four different borole compounds in their neutral and reduced states based on two aromaticity indices, namely nucleus-independent chemical shift (NICS) and multicenter indices (MCI), calculated at the PBE0/6-31+G(d,p) level of theory. Both indices corroborate the notion that neutral borole compounds are antiaromatic a...

Journal: :The Journal of organic chemistry 2004
Jordi Poater Miquel Solà Rosario G Viglione Riccardo Zanasi

In this work, we have analyzed the local aromaticity of the six-membered rings (6-MRs) of planar and pyramidalized pyracylene species through the structurally based harmonic oscillator model of aromaticity (HOMA), the electronically based para-delocalization index (PDI), and the magnetic-based nucleus independent chemical shift (NICS) measurements, as well as with maps of ring current density. ...

Journal: :Physical chemistry chemical physics : PCCP 2011
Santanab Giri Sateesh Bandaru Arindam Chakraborty Pratim K Chattaraj

Hydrogen storage capacity of some Li(+)/F(-) doped neutral and charged aromatic/antiaromatic systems is studied at the B3LYP, M05-2X, MPW1K and MP2 levels of theory. Various conceptual density functional theory based global and local reactivity descriptors, nucleus independent chemical shift (NICS), NICS-rate, interaction energy per H(2) molecule, reaction enthalpy and reaction electrophilicity...

Journal: :Dalton transactions 2015
J Oscar C Jimenez-Halla Eduard Matito Miquel Solà Holger Braunschweig Christian Hörl Ivo Krummenacher Johannes Wahler

In this contribution, we have evaluated the (anti)aromatic character of thirty-four different borole compounds in their neutral and reduced states based on two aromaticity indices, namely nucleus-independent chemical shift (NICS) and multicenter indices (MCI), calculated at the PBE0/6-31+G(d,p) level of theory. Both indices corroborate the notion that neutral borole compounds are antiaromatic a...

Journal: :Physical chemistry chemical physics : PCCP 2012
Zahra Badri Cina Foroutan-Nejad Parviz Rashidi-Ranjbar

The influence of various all-electron basis sets and effective core potentials employed along with several DFT functionals (B3LYP, B3PW91, BLYP, BP86 and M06) on the magnitude of nucleus independent chemical shift (NICS) values in different metallic nano-clusters and hydrocarbons is studied. In general, it is demonstrated that the NICS values are very sensitive to the applied method/basis set; ...

Journal: :Organic letters 2010
Yan Wang Judy I-Chia Wu Qianshu Li Paul von Ragué Schleyer

The most refined nucleus-independent chemical shift index (NICS(0)(πzz)) and the extra cyclic resonance energies (ECREs), based on the block localized wave function (BLW) method, show that the aromaticity of all azines is like that of benzene. The same is true for aza-naphthalenes relative to naphthalene. The lower relative energies of isomers with vicinal N's are due to the weakness of NN bond...

Journal: :Chemistry 2023

Here, five bonds to carbon through tri-coordination are theoretically established in the global minimum energy isomers of Al3C3− anion (1a) and Al3C3 neutral (1n) for first time. Various Al3C3−/0 identified using density functional theory at PBE0-D3/def2-TZVP level. Chemical bonding features thoroughly analyzed these two (1a 1n) with different topological quantum chemical tools, such as adaptiv...

Hossein Ghiasi Reza Ghiasi

The structures and properties of [n]sila-acenes (n=2-4) were investigated by density functional theory method. The results of calculations were obtained at B3LYP/6-311G (d,p) level on model species. Energetic criteria suggest that 2-1b (n=2), 3-1b (n=3), and 4-1b (n=4) isomers enjoy stabilization. By frontier orbital analysis, these systems are among the most stable of the family. Also, calcula...

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