Dual emission from 2-(4′-N,N-dimethylaminophenyl)pyridoimidazole–nanoparticle composite: Effect of β-cyclodextrin

Nanoparticle and surfactant controlled switching between proton transfer and charge transfer reaction coordinates

“…The SPR band of silver nanoparticles is usually observed at B430 nm and the size and shape of the particles influence the band position. 32 The SPR band of the silver nanoparticle in the presence of DHP is observed at 450 nm. The DLS studies reveal that the average size of the nanoparticles is smaller in the presence of DHP than in the absence of DHP (Fig.…”

“…This shows that DHP is attached to the nanoparticle through the pyridyl nitrogen. It was reported that the ICT emission was quenched and the normal emission was enhanced when trans-2-[4-(dimethylamino)styryl]benzothiazole attached to the nanoparticle through its electron donating 32 The tautomer emission of DHP is due to the transfer of an intramolecular proton of the 'OH' group to imidazole nitrogen in the excited state. On the other hand, the TICT emissions of DHP and dimethylamino derivative imidazopyridines are induced by excited state intermolecular proton transfer from the imidazole nitrogen (N3) to pyridyl nitrogen (N1) (Scheme S1, ESI ‡).…”

“…24,25 A few reports are present showing the interaction of ESIPT active or TICT active fluorophores with silver nanoparticles. [26][27][28][29][30][31][32][33][34][35] The interaction of silver nanoparticles with a set of ESIPT active imidazole derivative fluorophores has been studied and it was reported that the fluorophores stabilize the nanoparticles whereas the nanoparticles hamper the ESIPT process of the fluorophores. 26 Bojarski et al reported that on the silver nanoparticle surface the ESIPT fluorescence of flavonol was enhanced, which enables it to determine the low-activity hydrolase enzymes.…”

“…28 The interaction of dimethylamino derivative imidazopyridine with silver nanoparticle induces the TICT emission of the fluorophore. 32 However, the interaction of silver nanoparticles with trans-2-[4-(dimethylamino)styryl]benzothiazole quenches its TICT emission. 35 Similarly the interaction of trans-3-(4monomethylaminophenyl)acrylonitrile with silver nanoparticles quenches it's ICT emission.…”