Urea-functionalized 4-ethynylbenzenes undergo facile formal [2 + 2] cycloaddition followed by retroelectrocyclization upon reaction with tetracyanoethylene, yielding 1,1,4,4-tetracyanobuta-1,3-dienes-based push–pull chromophores. Unlike the N,N′-dialkylamino group, urea functionalization provides easy access to further functionalization on these chromophores. The resulting chromophores exhibit unexpected white light emissions apart from various inherent properties like intramolecular charge-transfer band and redox behavior.

A simple color change detection by the naked-eye using untreated paper for a biologically relevant fluoride (F -) anion in water is a challenge. New non-planar push-pull chromophore involving intramolecular charge-transfer (ICT) from urea donor in 2,3disubstituted-1,1,4,4-tetracyanobuta-1,3-diene (TCBD) turns out to be an efficient system for detecting Fion giving various output signals. But, replacing phenyl (Ph) at C3-position with 4-(dimethylamino)phenyl (DMA) led to the absence of colorimetric and fluorometric detections due to the masking and quenching, nature of strong ICT by the DMA. NMR and electrochemical studies revealed that the sensing mechanism is governed by H-bonding as well as the deprotonation of N-H attached with TCBD moiety which reduces the HOMO-LUMO gap and causes the dramatic color change. Coupled with excellent sensitivity (3 ppm) and specificity towards F -, a successful demonstration of cheap tissue paper-based visual stripdetection in aqueous is presented.

Rechargeable metal-air batteries are an emerging electrochemical energy storage technology wherein the invention of bifunctional electrocatalysts for oxygen reduction (ORR) and evolution reactions (OER) play a critical role in the...

Organic solvents limit [2+2] cycloaddition-retroelectrocyclization (CA–RE) in biological fields. We examined the formation of 1,1,4,4-tetracyanobuta-1,3-dienes (TCBDs) through CA–RE reactions and their unusual reactivity to produce N-heterocyclic compounds when surfactant nature...

A simple color change detection by the naked-eye using untreated paper for a biologically relevant fluoride (F^–) anion in water is a challenge. New non-planar push-pull chromophore involving intramolecular charge-transfer (ICT) from urea donor in 2,3-disubstituted-1,1,4,4-tetracyanobuta-1,3-diene (TCBD) turns out to be an efficient system for detecting F^–ion giving various output signals. But, replacing phenyl (Ph) at <i>C</i>₃-position with 4-(dimethylamino)phenyl (DMA) led to the absence of colorimetric and fluorometric detections due to the masking and quenching, nature of strong ICT by the DMA. NMR and electrochemical studies revealed that the sensing mechanism is governed by H-bonding as well as the deprotonation of N–H attached with TCBD moiety which reduces the HOMO–LUMO gap and causes the dramatic color change. Coupled with excellent sensitivity (3 ppm) and specificity towards F^–, a successful demonstration of cheap tissue paper-based visual strip-detection in aqueous is presented.