Molecular photochemistry. XXXIX. External heavy-atom-induced spin-obital coupling. Spectroscopic study of naphthonorbornanes

Abstract

Scientific Research for its generous support of this research.(2) (a) M. Kasha, J. Chem. Phys., 20, 71 (1952); (b) M. Kasha,

Controlling Organic Room Temperature Phosphorescence through External Heavy‐Atom Effect for White Light Emission and Luminescence Printing

“…Currently, one of the most popular ways to achieve organic phosphorescence is to introduce the heavy atoms (Br or I) into the luminescent skeletons to promote the intersystem crossing (ISC) rate . The phosphorescence efficiency of the luminophore can be significantly improved by using this approach because of the notable increase in spin–orbit coupling (SOC) induced by the heavy‐atom effect (HAE) . Even though the HAE approach has routinely been used as an effective strategy to achieve RTP, the heavy atoms are generally covalently linked to the luminophores, which makes achieving a tunable RTP difficult and inconvenient.…”

Conjugated Oligomers with Stable Radical Substituents: Synthesis, Single Crystal Structures, Electronic Structure, and Excited State Dynamics

“…Strategies to promote generation of triplet excitons predominately rely either on incorporation of heavy atoms into chromophores , or singlet fission . Design of heavy-atom free organic compounds that result in enhanced ISC (EISC) is of great interest but remains a significant challenge.…”

External Heavy-Atom Effect via Orbital Interactions Revealed by Single-Crystal X-ray Diffraction

“…It is considered that the EHE is executed through the orbital interactions between the heavy-atom perturber and the luminophore. 3 Although the EHE has been routinely used to boost molecular phosphorescence 4,5,6,7,8,9,10,11,12 for various applications, 13,14,15 very few reports are focused on the mechanistic perspective. 16 Here, we synthesized two types of organic aromatic molecules, carbazole and quinolinium derivatives (Chart 1), based on the relative energy-level of the HOMO (or basicity) / LUMO (or acidity) and combine them with heavy-atom perturbers to generate room-temperature phosphorescence (RTP) 17,18 in the solid state.…”

“…It is considered that the EHE is executed through the orbital interactions between the heavy-atom perturber and the luminophore . Although the EHE has been routinely used to boost molecular phosphorescence − for various applications, − very few reports are focused on the mechanistic perspective …”