~(11)B NMR AND QUANTUM CHEMISTRY STUDIES OF BORATRANE COMPOUNDS

• 作 者: 孙贤育 朱晋昌 伍华菊 蒋丽金 吴观丽 吴冶新 鲁开娟
• 机 构: Institute of Photographic Chemistry, Academia Sinica, Beijing,Institute of Photographic Chemistry, A
• 出 处: Science in China,Ser.B
• 发表日期: 1986年12期
• 关键词: dative covalent analogous steric bonds purely rings stronger boron orbital

The ~(11)B chemical shifts of boratrane compounds were measured. Quantum chemistry calculations of some of the compounds wore carried out using the CNDO/2 method. Both experimental and calculated results confirmed the existence of the B←N dative bonds in boratranes. The exporimental results indicate that the ~(11)B chemical shifts are influenced by the size of the rings, the characteristics of substituents and steric factors. The calculated results indicate that the strengths of the B←N dative bonds in boratranes are about half of that of a purely “covalent two-electron bond” and therefore, the dative bonds B←N are stronger than those of Si←N in the analogous silatranes, and the boratranes are more stable than silatranes.

Quantum chemistry calculations of some of the compounds wore carried out using the CNDO / 2 method. Both experimental and calculated results confirmed the existence of the B ← N dative bonds in boratranes. The exporimental results indicate that the ~ (11) B chemical shifts are influenced by the size of the rings, the characteristics of substituents and steric factors. The calculated results indicate that the strengths of the B ← N dative bonds in boratranes are about half of that of a purely “covalent two-electron bond” and therefore, the dative bonds B ← N are stronger than those of Si ← N in the analogous silatranes, and the boratranes are more stable than silatranes.