scholarly journals Energetic and Geometric Characteristics of Substituents, Part 3: The Case of NO2 and NH2 Groups in Their Mono-Substituted Derivatives of Six-Membered Heterocycles

Symmetry ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 145
Author(s):  
Paweł A. Wieczorkiewicz ◽  
Halina Szatylowicz ◽  
Tadeusz M. Krygowski

Substituted heterocyclic arenes play important roles in biochemistry, catalysis, and in the design of functional materials. Exemplary six-membered heteroaromatic molecules, that differ from benzene by inclusion of one heteroatom, are pyridine, phosphorine, arsabenzene, and borabenzene. This theoretical study concerns the influence of the heteroatom present in these molecules on the properties of substituents of two types: electron-donating (ED) NH2 group and electron-accepting (EA) NO2 group, attached at the 2-, 3-, or 4-position. The effect is evaluated by the energy of interaction (Erel) between the substituent and the substituted system and electronic properties of the substituents described by the charge of the substituent active region (cSAR) index. In addition, several geometric descriptors of the substituent and heteroaromatic ring, as well as changes in the aromaticity, are considered. The latter are assessed using the Electron Density of Delocalized Bonds (EDDBs) property of delocalized π electrons. The obtained results show that the electronegativity (EN) of the heteroatom has a profound effect on the EA/ED properties of the substituents. This effect is also reflected in the geometry of studied molecules. The Erel parameter indicates that the relative stability of the molecules is highly related to the electronic interactions between the substituent and the heteroarene. This especially applies to the enhancement or weakening of π-resonance due to the EN of the heteroatom. Additionally, in the 2-heteroarene derivatives, specific through-space ortho interactions contribute to the heteroatom effects.

2017 ◽  
Vol 41 (18) ◽  
pp. 10251-10258 ◽  
Author(s):  
Yating Shi ◽  
Yarui Shi ◽  
Huiling Wei ◽  
Hongsheng Zhai ◽  
Yufang Liu

Two new contorted polycyclic aromatic hydrocarbons (PAHs) 1 and 2 have been synthesized by Perepichka and coworkers (Org. Lett., 2015, 17, 4224).


Author(s):  
Chao-Jiang Zhang ◽  
Peng Wang ◽  
Xi-Ling Xu ◽  
Hong-Guang Xu ◽  
Weijun Zheng

The AlnC5- (n = 1-5) clusters were detected in the gas-phase and were investigated by mass-selected anion photoelectron spectroscopy. The structures of AlnC5-/0 (n = 1-5) were explored by theoretical...


2021 ◽  
Author(s):  
Anurag Mukherjee ◽  
Suhrit Ghosh

Naphthalene-diimide (NDI) derived building blocks have been explored extensively for supramolecular assembly as they exhibit attractive photophysical properties, suitable for applications in organic optoelectronics. Core-substituted derivatives of the NDI chromophore (cNDI) differ significantly from the parent NDI dye in terms of optical and redox properties. Adequate molecular engineering opportunities and substitution-dependent tunable optoelectronic properties make cNDI derivatives highly promising candidates for supramolecular assembly and functional material. This short review discusses recent development in the area of functional supramolecular assemblies based on cNDIs and related molecules.


Author(s):  
S. Gallego-Parra ◽  
R. Vilaplana ◽  
O. Gomis ◽  
E. Lora da Silva ◽  
A. Otero-de-la-Roza ◽  
...  

We report a joint experimental and theoretical study of the low-pressure phase of α′-Ga2S3 under compression. The structural, vibrational, topological and electronic properties have been evaluated to reveal the relevance of the vacancy channels and the single and double lone electron pairs in the pressure behaviour of this system.


Biopolymers ◽  
2014 ◽  
Vol 101 (10) ◽  
pp. 1038-1050 ◽  
Author(s):  
Sheh-Yi Sheu ◽  
Chao-Hsien Huang ◽  
Jia-Kai Zhou ◽  
Dah-Yen Yang

1993 ◽  
Vol 07 (26) ◽  
pp. 4305-4329 ◽  
Author(s):  
C.Z. WANG ◽  
B.L. ZHANG ◽  
K.M. HO ◽  
X.Q. WANG

The recent development in understanding the structures, relative stability, and electronic properties of large fullerenes is reviewed. We describe an efficient scheme to generate the ground-state networks for fullerene clusters. Combining this scheme with quantum-mechanical total-energy calculations, the ground-state structures of fullerenes ranging from C 20 to C 100 have been studied. Fullerenes of sizes 60, 70, and 84 are found to be energetically more stable than their neighbors. In addition to the energies, the fragmentation stability and the chemical reactivity of the clusters are shown to be important in determining the abundance of fullerene isomers.


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