hybrid-dft study and nbo interpretations of the conformational behavior of 1,2-dihalodisilanes

نویسندگان

davood nori-shargh

department of chemistry, arak branch, islamic azad university, arak, iran seiedeh negar mousavi

department of chemistry, arak branch, islamic azad university, arak, iran hooriye yahyaei

department of chemistry, zanjan branch, islamic azad university, zanjan, iran somayye yazdani

department of chemistry, arak branch, islamic azad university, arak, iran bahareh ahmadi

چکیده

hybrid-density functional theory (b3lyp/def2-tzvpp) based method and nbointerpretation were used to investigate the conformational behavior of 1,2-dihalodisilanes[halo=f (1), cl (2), br (3), i (4)]. the b3lyp/def2-tzvpp results showed that the anticonformations of compounds 1-4 are more stable than their corresponding gaucheconformations. the stability of the anti conformation compared to the gauche conformationincreases from compound 1 to compound 4. the nbo analysis of donor-acceptor interactionsshowed that the generalized anomeric effect (gae) is in favor of the gauche conformations ofcompounds 1 and 2. contrary to compounds 1 and 2, gae is in favor of the anti conformationsof compounds 3 and 4. the gae values calculated (i.e. gaeanti-gaegauche) increase fromcompound 1 to compound 4. on the other hand, the calculated dipole moment values for thegauche conformations increase from compound 1 to compound 3 but decreases from compound3 to compound 4. based on the results obtained, there is no conflict between the gae and theelectrostatic model impacts on the conformational preferences in compounds 1-3 but theelectrostatic model can not rationalize the increase of the instability of the gauche conformationof compound 4 compared to its anti conformation on going from compound 3 to compound 4.consequently, in the conflict between the gae and the electrostatic model, the former succeededin accounting for the increase of the anti conformation stability from compound 1 to compound4. there is a direct correlation between the calculated gae, δ[rsi-si(g)-rsi-si(a)] parameters. thecorrelations between the gae, bond orders, δganti-gauche, δg‡(gauche→gauche′, c2v),δg‡(anti→gauche, c2), dipole-dipole interactions, structural parameters and conformationalbehaviors of compounds 1-4 have been investigated.

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Hybrid-DFT study and NBO interpretations of the conformational behavior of 1,2-dihalodisilanes

Hybrid-density functional theory (B3LYP/Def2-TZVPP) based method and NBOinterpretation were used to investigate the conformational behavior of 1,2-dihalodisilanes[halo=F (1), Cl (2), Br (3), I (4)]. The B3LYP/Def2-TZVPP results showed that the anticonformations of compounds 1-4 are more stable than their corresponding gaucheconformations. The stability of the anti conformation compared to the g...

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عنوان ژورنال:
journal of the iranian chemical research

جلد ۴، شماره ۴، صفحات ۲۰۷-۲۱۷

کلمات کلیدی
[ ' g e n e r a l i z e d a n o m e r i c e f f e c t s ' , ' s t e r e o e l e c t r o n i c i n t e r a c t i o n s ' , ' a b i n i t i o ' , ' n b o ' , 1 , 2 , ' d i h a l o d i s i l a n e s ' ]

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