“Extra stabilisation” of a pyrene based molecular couple by γ-cyclodextrin in the excited electronic state

Abstract

Two thiosemicarbazide and semicarbazide functionalized pyrene labeled Schiff base compounds have been synthesized. The pyrene moieties in the compounds result in formation of π-π coupled complexes in aqueous medium in the excited electronic state. Added γ-cyclodextrin allows incorporation of the pyrene head inside its less polar core and promotes hydrogen bonding of the thio and oxo groups of the compounds with its rim hydroxyl groups to "stabilise" the monomers. This is confirmed by FT-IR and absorption spectroscopy. The stabilised monomers lead to formation of stabilised excimers as monitored by steady state and time-resolved fluorescence spectroscopy through varying the experimental conditions. The proposed model for the stabilisation of the Schiff base monomers has been evidenced by comparing with the fluorescence spectroscopic changes of two control compounds. The present work reports a step ahead toward proposing a simple host-guest method to extra stabilise the pyrene based excimers that can be biologically utilised.

The Synthesis of Thiosemicarbazone-Based Aza-Ylides as Inhibitors of Rat Erythrocyte Glucose 6-Phosphate Dehydrogenase Enzyme

“…All spectroscopic data for 3c is compatible with the literature (Lee et al, 2010 2, 131.8, 130.8, 130.1, 128.7, 128.6, 128.2, 127.4, 126.9, 126.5, 126.0, 125.7, 125.1, 124.2, 124.0, 123.8, 121.6. All spectroscopic data for 3d is compatible with the literature (Wang et al, 2010;Ghosh et al, 2012;Bayindir et al, 2019). 163.3, 143.1, 132.4, 131.6, 122.8, 121.1, 120.7, 111.5.…”

Morphology directing synthesis of 1-pyrene carboxaldehyde microstructures and their photo physical properties

“…When the dielectric constant (3) of the solvent exceeds 10, the emission is broad (400-500 nm) and moderately intense and it is coming exclusively from the (p, p*) excited state. 30 The emission spectra of 1-PyCHO (1 mM) in ethanol (3 ¼ 24.5) shows a maximum at 440 nm typical from a solvent of high polarity (Fig. 6d) and that of concentrated solution (5 mM) has an emission maxima at 470 nm.…”

Regulation of photodynamic interactions in 1,8-naphthalimide–linker–phenothiazine dyads by cyclodextrins

“…[1][2][3][4] Thus CDs are able to form complexes with various compounds through host-guest interactions that affect the photophysical and photochemical properties of guest molecules. [5][6][7][8][9] The CDs have various cavity diameters, which provide a diversity of encapsulation patterns with guest molecules inside their cavities. This inclusion ability of the CDs has been widely used for pharmaceutical and various other analytical purposes.…”