Acta Phys. -Chim. Sin. ›› 2018, Vol. 34 ›› Issue (2): 201-207.doi: 10.3866/PKU.WHXB201707131

Special Issue: 密度泛函理论中的化学概念特刊

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Bonding and Reactivity in RB-AsR Systems (R=H, F, OH, CH3, CMe3, CF3, SiF3, BO):Substituent Effects

Manas GHARA,Pratim K. CHATTARAJ*()   

  • Received:2017-06-22 Published:2017-11-13
  • Contact: Pratim K. CHATTARAJ E-mail:pkc@chem.iitkgp.ernet.in

Abstract:

Density functional theory-based calculations have been carried out to study the bonding and reactivity in RB-AsR (R=H, F, OH, CH3, CMe3, CF3, SiF3, BO) systems. Our calculations demonstrated that all the studied systems adopted bent geometry (∠R-B-As ≈ 180° and ∠B-As-R ≈ 90° or less). The reason for this bending was explained with the help of a valence-orbital model. The potential energy surfaces for three possible isomers of RB-AsR systems were also generated, indicating that the RB-AsR isomer was more stable than R2B-AsR when R=SiF3, CMe3, and H. The B-As bond character was analyzed using natural bond orbital (NBO) and Wiberg bond index (WBI) calculations. The WBI values for B-As bonds in F3SiB-AsSiF3 and HB-AsH were 2.254 and 2.209, respectively, indicating that this bond has some triple-bond character in these systems. While the B centers prefer nucleophilic attack, the As centers prefer electrophilic attack.

Key words: Density-functional theory, Bent geometry, Wiberg bond index, Reactivity, Multiphilic descriptor