Photophysical properties of tris-methoxycoumarin derivative of a cryptand

Time resolved studies of dual emission and photoinduced energy transfer in a Tris methoxy coumarin derivative of a cryptand and its complex with Tb(NO3)3

“…Bharadwaj) was synthesized following literature procedure [12]. All the solvents used were of spectral grade and further dried by standard procedures.…”

“…1A and B) where three methoxy-coumarin moieties are attached to cryptand unit by a CH 2 spacer [12]. This system exhibits intramolecular PET from the receptor nitrogen atoms of the cryptand moiety to the coumarin units reducing the fluorescence quantum yield of coumarin in the ligand [12]. Another unique feature for the above system was the observation of a red shifted second luminescence band at room temperature in various solvents, the assignment of which was somewhat tentative [12].…”

“…Photophysical studies with an emphasis on photoinduced electron transfer (PET) in supramolecular systems having 'fluorophore-spacer-receptor' configuration have been carried out in various laboratories in view of their potential use as molecular sensors, molecular switching devices and to understand the mechanism of PET [4][5][6]. The effect of varying the spacer and the dimension and nature of the receptor moiety on the photophysical properties of different fluorophores have been studied earlier in our laboratory [7][8][9][10][11][12].…”

“…1A and B) where three methoxy-coumarin moieties are attached to cryptand unit by a CH 2 spacer [12]. This system exhibits intramolecular PET from the receptor nitrogen atoms of the cryptand moiety to the coumarin units reducing the fluorescence quantum yield of coumarin in the ligand [12].…”

“…This system exhibits intramolecular PET from the receptor nitrogen atoms of the cryptand moiety to the coumarin units reducing the fluorescence quantum yield of coumarin in the ligand [12]. Another unique feature for the above system was the observation of a red shifted second luminescence band at room temperature in various solvents, the assignment of which was somewhat tentative [12]. This paper deals with (i) detailed time resolved studies of the dual emissions observed at room temperature in various solvents of the above system (ii) study of photoinduced intramolecular energy transfer (ET) at room temperature and at 77 K in terbium (III) complex of the above system where NO À 3 ion used as counter anion.…”