Abstract
We investigated the luminescence properties and color tuning of [Pt(dpb)Cl] (dpbH=1,3-di(2-pyridyl)benzene) and its analogues. An almost blue emission was obtained for the complex [Pt(Fmdpb)CN] (FmdpbH=4-fluoro-1,3-di(4-methyl-2-pyridyl)benzene), modified by the introduction of F and CH3 groups to the dpb ligand and the substitution of Cl by CN. As the concentration of the solution was increased, the color of the emission varied from blue to white to orange. The color change resulted from a monomer-excimer equilibrium in the excited state. A broad emission spectrum around 620 nm was clearly detected along with a structured monomer emission around 500 nm. Upon further increases in concentration, another broad peak appeared in the longer wavelength region of the spectrum. We assigned the near-infrared band to the emission from an excited trimer generated by the reaction of the excimer with the ground-state monomer. The emission lifetimes of the monomer, dimer, and trimer were evaluated as τM =12.8 μs, τD =2.13 μs, and τT =0.68 μs, respectively, which were sufficiently long to allow association with another Pt(II) complex and dissociation into a lower order aggregate. Based on equilibrium constants determined from a kinetic study, the formation of the excimer and the excited trimer were concluded to be exothermic processes, with ΔG*D =-24.5 kJ mol(-1) and ΔG*T =-20.4 kJ mol(-1) respectively, at 300 K.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.