Premium
Design of Green‐Emitting Salts from Substituted Pyridines: Understanding the Solid‐State Photodimerization of trans ‐1,2‐bis(4‐pyridyl)ethylene
Author(s) -
Peedikakkal Abdul Malik Puthan,
AlMohsin Hasan,
Jalilov Almaz,
Sølling Theis I.,
Skov Anders B.
Publication year - 2021
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.202100143
Subject(s) - chemistry , stereospecificity , ethylene , solid state , photochemistry , yield (engineering) , crystal structure , solvent , ion , crystallography , organic chemistry , materials science , catalysis , metallurgy
Abstract Polymorphic salts of trans ‐1,2‐bis(4‐pyridyl)ethylene ( bpe ), 2 [bpeH 2 ] ⋅ (SO 4 )(2HSO 4 ) ( 1 ) and [bpeH 2 ] ⋅ 2HSO 4 ( 2 ) have been synthesized and their structures determined by X‐ray crystallography. The Schmidt postulate predicts that neither of the salts will give rise to photodimerization so they can both potentially be applied as green light emitters. Despite the predictions, 1 undergoes a stereospecific solid‐state photodimerization reaction with 100 % yield. This is due to UV induced combination of sliding and pedal‐like movement of the pyridyl ring system that influences the alignment of C=C bonds. The sliding motion is restricted in 2 . Consequently, the green emission from 1 is completely quenched after photodimerization. It is evident that counter ions play a dominant role in dis‐ and enabling photodimerization; their degree of protonization and lattice placement are important solvent controlled design parameters towards crystal structures that can act as future light emitters.