scholarly journals Effects of the Electronegativity of Second Row Elements on Their Bonding to Boron

2016 ◽  
Vol 13 (3) ◽  
Author(s):  
Xavier Shiu ◽  
J Conceicao
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Bond Formation ◽  
Nbo Analysis ◽  
Functional Theory ◽  
Donor And Acceptor ◽  
Natural Bonding Orbital ◽  
Bonding Properties ◽  
Moller Plesset ◽  
Octet Rule

The effects of electronegativity on the bonding between boron and second row elements are studied in this paper. Calculations using Density Functional Theory (DFT), Moller-Plesset Theory (MP2) and Natural Bonding Orbital (NBO) analysis were performed on BF3, B(OH)3 and B(NH2)3 and the localized bonding properties of these molecules were elucidated. All of these molecules showed the absence of pi-bonding and did not obey the octet rule. With decreasing electronegativity of the terminal atoms, F, O and N in BF3, B(OH)3, B(NH2)3 there is increasing the propensity of electron donation from these terminal atoms to the empty p-orbital of the central boron. Within the BH2−F, BH2−OH and BH2−NH2 series, the amino-borane showed the largest change in relative bond length and angle across this set. Furthermore, the borate anion, −O−B(OH) 2 was subjected to identical analysis and pi-bond formation was observed. Our results show that a good match orbital energies between the donor and acceptor orbitals are important for pi-bond formation. KEYWORDS: Electronegativity; Boron Trifluoride; Boric Acid; Triaminoborane; Borate Anion; Octet Rule; Density Functional Theory; Natural Bonding Orbital; Pi-Bond; Double Bond

scholarly journals Electron Donor and Acceptor Influence on the Nonlinear Optical Response of Diacetylene-Functionalized Organic Materials (DFOMs): Density Functional Theory Calculations

Molecules ◽  
2019 ◽  
Vol 24 (11) ◽  
pp. 2096 ◽  
Author(s):  
Muhammad Khalid ◽  
Riaz Hussain ◽  
Ajaz Hussain ◽  
Bakhat Ali ◽  
Farrukh Jaleel ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Gas Phase ◽  
Electron Donor ◽  
Density Functional ◽  
Nbo Analysis ◽  
Basis Set ◽  
First Hyperpolarizability ◽  
Functional Theory ◽  
Parent Molecule ◽  
Donor And Acceptor

Herein, we report the quantum chemical results based on density functional theory for the polarizability (α) and first hyperpolarizability (β) values of diacetylene-functionalized organic molecules (DFOM) containing an electron acceptor (A) unit in the form of nitro group and electron donor (D) unit in the form of amino group. Six DFOM 1–6 have been designed by structural tailoring of the synthesized chromophore 4,4′-(buta-1,3-diyne-1,4-diyl) dianiline (R) and the influence of the D and A moieties on α and β was explored. Ground state geometries, HOMO-LUMO energies, and natural bond orbital (NBO) analysis of all DFOM (R and 1–6) were explored through B3LYP level of DFT and 6-31G(d,p) basis set. The polarizability (α), first hyperpolarizability (β) values were computed using B3LYP (gas phase), CAM-B3LYP (gas phase), CAM-B3LYP (solvent DMSO) methods and 6-31G(d,p) basis set combination. UV-Visible analysis was performed at CAM-B3LYP/6-31G(d,p) level of theory. Results illustrated that much reduced energy gap in the range of 2.212–2.809 eV was observed in designed DFOM 1–6 as compared to parent molecule R (4.405 eV). Designed DFOM (except for 2 and 4) were found red shifted compared to parent molecule R. An absorption at longer wavelength was observed for 6 with 371.46 nm. NBO analysis confirmed the involvement of extended conjugation and as well as charge transfer character towards the promising NLO response and red shift of molecules under study. Overall, compound 6 displayed large <α> and βtot, computed to be 333.40 (a.u.) (B3LYP gas), 302.38 (a.u.) (CAM-B3LYP gas), 380.46 (a.u.) (CAM-B3LYP solvent) and 24708.79 (a.u.), 11841.93 (a.u.), 25053.32 (a.u.) measured from B3LYP (gas), CAM-B3LYP (gas) and CAM-B3LYP (DMSO) methods respectively. This investigation provides a theoretical framework for conversion of centrosymmetric molecules into non-centrosymmetric architectures to discover NLO candidates for modern hi-tech applications.

scholarly journals Tipping the balance: theoretical interrogation of divergent extended heterolytic fragmentations

2020 ◽  
Vol 11 (8) ◽  
pp. 2231-2242 ◽  
Author(s):  
Croix J. Laconsay ◽  
Ka Yi Tsui ◽  
Dean J. Tantillo
Keyword(s):  
Molecular Dynamics ◽  
Density Functional Theory ◽  
Electric Field ◽  
Ab Initio ◽  
External Electric Field ◽  
Density Functional ◽  
Natural Bond Orbital ◽  
Nbo Analysis ◽  
Functional Theory

We interrogate a type of heterolytic fragmentation called a ‘divergent fragmentation’ using density functional theory (DFT), natural bond orbital (NBO) analysis, ab initio molecular dynamics (AIMD), and external electric field (EEF) calculations.

Density functional theory and Møller-Plesset studies of hindered rotations of acetone

2008 ◽  
Vol 14 (12) ◽  
pp. 1173-1181
Author(s):  
M. Heidari ◽  
H. Rahemi ◽  
A. Tarashi ◽  
S. F. Tayarri
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Functional Theory ◽  
Moller Plesset
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