Theoretical Studies On Modulation Of Main Group Element For Transition Metal Complexes

In recent years, transition metal complexes have become a fascinating field for their diverse potential applications in memory, flat-panel displays, and sensors, because of excellent photophysical properties and various electronic properties. Especially in the field of optoelectronic materials, Platinum, iridium and rhenium complexes have attracted increasing attention, because they can utilize the decay of triplet exciton to increase phosphorescent efficiency. With the development of research, it is more and more important to study molecule design, electronic structures, excited state properties, photophysical properties and charge transfer properties through quantum chemical methods.In this paper, we have systematically studied the electronic structure, excited state properties, spectroscopic properties and charge transfer propeties of several kinds of platinum complexes, rhenium and iridium complexes. The following is the main results:1. A series of diarylethene-containing cyclometalated platinum(Ⅱ) complexes with different element groups have been investigated theoretically using DFT methods to study their electronic structures, spectroscopic properties and excited state properties. It is found that the introduction of different element groups can modulate absorption,1-B has the largest red-shift in accordance with the smallest band gap. In addition, their charge transfer propeties can be modulate by different element groups,1-B has better charge transfer property. It can be realized to tune their electronic and optical properties through introducing different element groups.2. We have studied the substituent ligand and their complex on the optical and electronic properties of both closed-ring and open-ring isomers by DFT/TDDFT calculation. It is found that the coordination of Re(Ⅰ) can efficiently increase the planarization of pyridyl and imidazoyl ring, leading to extend π-conjugation. Thus by the coordination and photocyclization, the near-infrared photochromic behavior is realized. Additionally, after coordinating to Re(Ⅰ), the hole-injection and hole-transportion ability decrease while electron-injection ability increase. Photocyclization leads to better balance between hole and electron transporting abilities. The substituent of dimesitylboryl group exhibits great influence on the photophysical, properties, its complex can also be used as a NIR F-probe.3. A series of Cyclometalated iridium (III) complexes have been designed with the introduction of different element groups on the N"N ligands. From the DFT calculation results, different element groups hardly affect the molecule structure at ground state, but make influences on energy level and band gap, the absorption of1-B,1-N and1-P shift red, the largest is1-N. Additionally,1-N has the best hole-injection property,1-P can change from hole to electron which masters charge transfer property.