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

Density functional theory-based calculations have been carried out to study the bonding and reactivity in RB-As R(R=H,F,OH,CH3,CMe_3,CF_3,SiF_3,BO)systems.Our calculations demonstrated that all the studied systems adopted bent geometry(DR-B-As≈180°andDB-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-As R systems were also generated,indicating that the RB-As R isomer was more stable than R_2B-As R when R=SiF_3,CMe_3,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 F3Si B-As SiF_3 and HB-As H 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.

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 RzB-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.