Theoretical Studies on Phosphorescent Materials: The Conjugation-Extended PtII Complexes

2014 ◽  
Vol 67 (10) ◽  
pp. 1522 ◽  
Author(s):  
Ai-Hua Liang ◽  
Fu-Quan Bai ◽  
Jian Wang ◽  
Jian-Bo Ma ◽  
Hong-Xing Zhang
Keyword(s):  
Charge Transfer ◽  
Decay Rate ◽  
Excited States ◽  
Rate Constants ◽  
Radiative Decay ◽  
Theoretical Study ◽  
Radiative Decay Rate ◽  
Ligand Charge Transfer ◽  
Emission Transition ◽  
Transfer Properties

A theoretical study on the PtII complex A based on a dimesitylboron (BMes2)-functionalized [Pt(C^N)(acac)] (C^N = 2-phenyl-pyridyl, acac = acetylaceton) complex, as well as three conjugation-extended analogues of the methylimidazole (C*) ligand BMes2-[Pt(C^C*)(acac)] complexes B–D is performed. Their theoretical geometries, electronic structures, emission properties, and the radiative decay rate constants (kr) were also investigated. The energy differences between the two highest occupied orbitals with dominant Pt d-orbital components (Δddocc) of D both at the ground and excited states are the smallest of all. Compared with B, the charge transfer in D possesses a marked trend towards the extended conjugated group, while C changed inconspicuously. The lowest-lying absorptions and the phosphorescence of them can be described as a mixed metal-to-ligand charge transfer (MLCT)/intra-ligand π→π* charge transfer (ILCT) and 3MLCT/3ILCT, respectively. The variation of charge transfer properties induced by extended conjugation and the radiative decay rate constants (kr) calculated revealed that D is a more efficient blue phosphorescence material with a 497 nm emission transition.

Synthesis and Photochemical Properties of Re(I) Tricarbonyl Complexes Bound to Thione and Thiazole-2-ylidene Ligands

2020 ◽  
Author(s):  
Matthew Stout ◽  
Brian Skelton ◽  
Alexandre N. Sobolev ◽  
Paolo Raiteri ◽  
Massimiliano Massi ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Ligand Exchange ◽  
Ligand Substitution ◽  
Bidentate Ligand ◽  
The Other ◽  
Ligand Exchange Reaction ◽  
Multiple Products ◽  
Ligand Charge Transfer ◽  
Photochemical Properties

<p>Three Re(I) tricarbonyl complexes, with general formulation Re(N^L)(CO)<sub>3</sub>X (where N^L is a bidentate ligand containing a pyridine functionalized in the position 2 with a thione or a thiazol-2-ylidene group and X is either chloro or bromo) were synthesized and their reactivity explored in terms of solvent-dependent ligand substitution, both in the ground and excited states. When dissolved in acetonitrile, the complexes bound to the thione ligand underwent ligand exchange with the solvent resulting in the formation of Re(NCMe)<sub>2</sub>(CO)<sub>3</sub>X. The exchange was found to be reversible, and the starting complex was reformed upon removal of the solvent. On the other hand, the complexes appeared inert in dichloromethane or acetone. Conversely, the complex bound to the thiazole-2-ylidene ligand did not display any ligand exchange reaction in the dark, but underwent photoactivated ligand substitution when excited to its lowest metal-to-ligand charge transfer manifold. Photolysis of this complex in acetonitrile generated multiple products, including Re(I) tricarbonyl and dicarbonyl solvato-complexes as well as free thiazole-2-ylidene ligand.</p>

Sign in / Sign up

Export Citation Format

Share Document