نتایج جستجو برای: nucleus independent chemical nics

تعداد نتایج: 917632  

One main group of organic chemistry is related to the aromatic compounds. In the present work, we replaced the CH group of benzene by silicon and nitrogen analogues. Then, Density functional theory (DFT) calculations were carried out for six-membered heterocyclic Si-N aromatic rings. Full geometry optimizations were performed in gas-phase, and at B3LYP level using 6-311++G(d,p) and CBSB7 basis ...

Journal: :Physical chemistry chemical physics : PCCP 2016
Sofie Van Damme Guillaume Acke Remco W A Havenith Patrick Bultinck

Aromatic compounds are characterised by the presence of a ring current when in a magnetic field. As a consequence, current density maps are used to assess (the degree of) aromaticity of a compound. However, often a more discrete set of so-called Nucleus Independent Chemical Shift (NICS) values is used that is derived from the current density. It is shown here that there is no simple one-to-one ...

Amir Hossein Hakimiounb Reza Ghiasi,

Equilibrium geometry, electronic structures, and vibrational modes of CoB8- were investigated in the PBEPBE/6-311+G(d,p) level of theory. The nucleus independent chemical shift (NICS) analysis and magnetizability values were used for studying of aromaticity in CoB8-. The effects of different solvents on the structure and frontier orbital energies were calculated using the polarizable continuum ...

Journal: :Journal of Chemical Physics 2021

We report on the construction and application of a new bond-current additivity scheme for polybenzenoid hydrocarbons. The method is based identification smaller substructures contained in system, up to tricyclic subunits. Thus, it enables prediction any cata-condensed unbranched hydrocarbon, using library consisting only four building blocks. predicted bond-currents can then be used generate Nu...

Journal: :Symmetry 2010
Miquel Solà Ferran Feixas J. Oscar C. Jiménez-Halla Eduard Matito Jordi Poater

The lack of reference aromatic systems in the realm of inorganic aromatic compounds makes the evaluation of aromaticity in all-metal and semimetal clusters a difficult task. To date, calculation of nucleus-independent chemical shifts (NICS) has been the most widely used method to discuss aromaticity in these systems. In the first part of this work, we briefly review our previous studies, showin...

Journal: :Chemical communications 2010
Sakya S Sen Herbert W Roesky Kathrin Meindl Daniel Stern Julian Henn A Claudia Stückl Dietmar Stalke

Reaction of LSi-SiL (1) (L = PhC(NtBu)(2)) with diphenyl alkyne gave the first example of a room temperature stable 1,4-disilabenzene. The compound was characterized by means of single crystal X-ray diffraction studies. NICS (nucleus independent chemical shift) calculations showed that the compound has some aromatic character.

Journal: :journal of physical & theoretical chemistry 2012
m. anafche f. naderi

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...

Journal: :iranian chemical communication 0
reza ghiasi 1department of chemistry, faculty of science, east tehran branch, islamic azad university, qiam dasht, tehran, iran amir hossein hakimiounb young researchers and elites club, north tehran branch, islamic azad university, tehran, iran

equilibrium geometry, electronic structures, and vibrational modes of cob8- were investigated in the pbepbe/6-311+g(d,p) level of theory. the nucleus independent chemical shift (nics) analysis and magnetizability values were used for studying of aromaticity in cob8-. the effects of different solvents on the structure and frontier orbital energies were calculated using the polarizable continuum ...

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