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采用量子化学ONIOM(B3LYP/6-31++G(d,p):UFF)方法研究限域在扶手椅型单壁硼氮纳米管[(SWBNNT(5,5)、SWBNNT(6,6)和SWBNNT(7,7)]内,α-Ala的结构和手性转变机制.分子结构分析表明:与单体α-Ala相比,受限于SWBNNT(5,5)内的α-Ala分子沿纳米管轴向被拉伸,骨架C-C-C键角和C-C-N-C二面角明显增大,其他结构参数略有变化;受限于SWBNNT((6,6)、(7,7))内的α-Ala结构变化愈来愈不明显.手性转变反应势能面计算结果表明:与单体α-Ala相比较,α-Ala在SWBNNT((5,5)、(6,6)、(7,7))内时,羧基内氢转移和氢从手性碳转移至羰基的能垒,随纳米管管径的降低而降低.手性转变反应路径研究发现:α-Ala在不同直径的SWBNNT((5,5)、(6,6)、(7,7))内时,完成手性转变所经历的反应路径条数以及过渡态和中间体的个数不同,体现了扶手椅型SWBNNT尺寸的变化对α-Ala手性转变反应通道的影响.
Quantum chemical ONIOM (B3LYP / 6-31 ++ G (d, p): UFF) method was used to investigate the effects of single-walled boron nitride nanotubes [(SWBNNT And SWBNNT (7,7)], the structure and the chiral transformation mechanism of α-Ala.Molecular structural analysis shows that α-Ala molecules restricted by SWBNNT (5,5) The CCC bond angle and the CCNC dihedral angle increased obviously along with the axial direction of the nanotube, while the other structural parameters changed slightly; Ala structure changes more and more obvious.Calculated transition potential energy surface results show that: Compared with the monomer α-Ala, α-Ala in SWBNNT ((5,5), (6,6), (7,7 )), The energy transfer of hydrogen transfer from the carboxyl group and the transfer of hydrogen from the chiral carbon to the carbonyl group decreased with the decrease of the tube diameter of the nanotubes.Research on the chiral transition route showed that: 5,5), (6,6), (7,7)), the number of reaction pathways and the number of transition states and intermediates that undergo chiral transition are different, which shows that armchair type SWBNNT Effect of changes on α - Ala chiral transformation channel.