Theoretical research on molecular motors based on 4,5‐diazafluorenyl coordination motifs

Abstract

AbstractThe 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.