Twisted Molecular Structure on Tuning Ultralong Organic Phosphorescence

Area of Science:

• Organic Chemistry
• Materials Science
• Photophysics

Background:

• Planar carbazole derivatives are common in phosphorescent materials.
• Understanding structure-property relationships is key for developing advanced organic phosphors.

Purpose of the Study:

• To investigate the photophysical properties of iminodibenzyl (Id) compared to planar carbazole.
• To explore the impact of molecular configuration on ultralong phosphorescence.
• To expand the library of ultralong organic phosphorescent (UOP) materials.

Main Methods:

• X-ray single-crystal analysis to determine molecular configurations.
• Photoluminescence spectroscopy at ambient and cryogenic (77 K) conditions.
• Theoretical calculations to correlate structure with photophysical properties.

Main Results:

• Iminodibenzyl (Id) exhibits blue-shifted ultralong phosphorescence (402 ms lifetime) in crystals due to a twisted structure.
• Multiple molecular configurations were identified in the crystal structure of Id.
• Phosphorescence color in solution shifted from blue to green with varying excitation wavelength at 77 K.
• Theoretical calculations confirmed the influence of molecular configurations on phosphorescent properties.

Conclusions:

• The twisted molecular structure and oscillating C-C bond in Id are crucial for its ultralong phosphorescence.
• Molecular configuration significantly impacts the photophysical properties of UOP materials.
• This study provides a bridge between molecular structure and UOP properties, paving the way for new material design.