The properties of naphthalene-containing molecular motors (L₁), pyrene-containing molecular motor (L₂), and two complexes (Zn (CN)₂(L₁) and Zn (CN)₂(L₂)) based on 4,5-diazafluorenyl coordination motifs are compared and analyzed. The influence of structural modification on the thermal helix inversion step is studied through density functional theory (DFT). The analysis of the rotation energy barrier shows that the expansion of the rotor structure of motor increases the energy barrier of the rotation process, but the motors L₁ and L₂ act as ligands to coordinate with the metal, which is an effective method to reduce the rotation energy barrier value. Through frontier molecular orbital (FMO), it is found that expanding the π-conjugation system in the rotor part of the motor can increase the chemical reactivity of the motor. Then the ultraviolet-visible (UV/Vis) absorption spectra of the motors is calculated, indicating the expansion of the π-conjugation system in the upper half of the molecular motor is a feasible method to move the excitation wavelength to the visible light region. Finally, hole-electron analysis is carried out. The expansion of the π-electron system of the motor rotor and the coordination of the rotor and metal can improve the efficiency of hole-electron separation and facilitate electron transfer.

中文翻译：

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基于4,5-二氮杂芴配位基序的分子马达的理论研究

基于4的含萘分子马达( L ₁ )、含芘分子马达( L ₂ )和两种配合物( Zn (CN) ₂ (L ₁ )和Zn (CN) ₂ (L ₂ ) )的性质,5-二氮杂芴基配位基序进行了比较和分析。通过密度泛函理论 (DFT) 研究了结构修饰对热螺旋反转步骤的影响。旋转能垒分析表明，电机转子结构的扩大增加了旋转过程的能垒，但电机L ₁和L ₂作为配体与金属配位，是降低旋转能垒值的有效方法。通过前沿分子轨道（FMO）发现，扩大电机转子部分的π共轭体系可以提高电机的化学反应性。然后计算电机的紫外-可见（UV/Vis）吸收光谱，表明分子电机上半部分的π共轭系统的扩展是将激发波长移动到可见光区域的可行方法。最后，进行空穴电子分析。电机转子π电子系统的扩展以及转子与金属的配合，可以提高空穴电子分离效率，促进电子转移。