Absorption and fluorescence spectra of 7-aminocoumarin derivatives

Reddy, A. Ramachandra; Prasad, D.Vijay; Darbarwar, M.

doi:10.1016/0047-2670(86)85008-0

Cited by 20 publications

(8 citation statements)

References 10 publications

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“…The general consensus from theoretical studies of 7-aminocoumarins is that the first three (longest wavelength) excitation peaks result from p-p* transitions 38-40 while a fourth, smaller peak at higher energy can be attributed to an n-p* transition. 38, 41 The p-p* transitions will primarily be considered and various studies have suggested that the excited p* energy levels arise from tautomerisation of the coumarin. 42, 43 From studying the energy changes that resulted from changing the substituents of 7-aminocoumarins, it was concluded that the longest wavelength singlet-singlet transition (S 0 -S 1 ) results from an intramolecular charge transfer from a p orbital associated with the benzene ring and nitrogen atom to a p orbital of the pyrone ring and carbonyl group.…”

Section: Fluorescence Propertiesmentioning

confidence: 99%

Investigations using fluorescent ligands to monitor platinum(iv) reduction and platinum(ii) reactions in cancer cells

et al. 2009

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Coordination of the aniline containing fluorophores, coumarin 120 (C120) and coumarin 151 (C151) at the non-leaving group positions of cisplatin analogues (giving cis-[PtCl(2)(C120)(NH(3))] and cis-[PtCl(2)(C151)(NH(3))]) resulted in partial and complete quenching of the fluorescence, respectively. Oxidation of the coumarin 120 complex to the Pt(iv) form (cis,trans,cis-[PtCl(2)(OH)(2)(C120)(NH(3))]) resulted in further quenching compared to that seen for the Pt(ii) complex. The fluorescence profiles of these coumarin complexes were collected to evaluate their suitability for studying the metabolism of cisplatin-based anticancer drugs. C151 has the more suitable profile with a lower energy excitation peak and a better separation between the excitation and emission spectra. The complete damping of fluorescence on coordination to Pt(ii) makes it unsuitable for monitoring the reduction process, but does allow it to be used to monitor loss of the aniline type ligand. All of the coumarin complexes revealed moderate cyotoxcities in the range 10-22 microM indicating that they are suitable models of anticancer agents. DNA dampens the fluorescence of both Pt(ii) complexes and that of C120 has a much higher DNA binding affinity (10 000 M(-1)) than does the complex of C151 (300 M(-1)). Treatment of A2780 human ovarian carcinoma cells with the Pt-coumarin complexes resulted in fluorescence visible by confocal microscopy, and co-localisation studies with organelle specific dyes suggest they are concentrated in the late endosomes or lysosomes. Cells treated with the Pt(iv) complex of C120 revealed strong fluorescence and a somewhat different distribution to cells treated with the Pt(ii) complex indicating reduction following uptake.

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Section: Fluorescence Propertiesmentioning

confidence: 99%

Investigations using fluorescent ligands to monitor platinum(iv) reduction and platinum(ii) reactions in cancer cells

et al. 2009

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“…The most investigated and commercially important groups are coumarins based dyes [1, 2, 3, 4]. Coumarin dyes exhibit intense fluorescence on substitution of various functional groups at different positions [5, 6, 7]. The fluorescence properties of coumarin derivatives can be altered by substituting different functional groups like amino, hydroxy and methoxy at the 7 th position.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and spectral properties of new fluorescent hydrazone disperse dyes and their dyeing application on polyester fabrics

Aysha

Zain

Arief

et al. 2019

Heliyon

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A new series of solid state fluorescent disperse dyes based on hybrid structure of pyrrolinone ester (PES)/coumarin moiety was prepared and fully characterized using spectroscopic analysis such as 1 HNMR, MS and IR spectra. The coumarin derivative (7- amino-4- methyl coumarin) was initially prepared from amino phenol via multi steps condensation reactions and its diazonium salt coupled with the pyrrolinone ester to form the hydrazone dyes. 1 HNMR data of the prepared dyes exhibited a pure hydrazone form as a mixture of E , Z isomers. These dyes showing a significant emission in solid state as well as on the dyed fabric. The dyeing application on polyester fabrics was investigated which showing that these dyes show high affinity to polyester fabric, and minor change in the dye affinity by changing pH even under alkaline conditions was observed.

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“…This phenomenon is known as a hypsochromic shift and can arise due to a number of factors, including aggregation of molecules in solution containing the complex or changes in solvent polarity. 28 However, no shifts in the spectrum were observed on the addition of the detergent Triton-X to the solution to disintegrate any aggregates present. The spectrum was also collected in different solvents including methanol, DMF, and DMSO and the hypsochromic shift remained.…”

Section: Fluorescence Studies Of the Synthesised Coumarin Complexesmentioning

confidence: 98%

Iron(iii) complexes of fluorescent hydroxamate ligands: preparation, properties, and cellular processing

et al. 2009

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Iron(III) complexes containing hydroxamic acid fluorophores were investigated as models of hypoxia selective prodrugs in vitro. Two complexes were synthesised, [Fe(c343haH)(3)] and [Fe(salen)(c343haH)]. The fluorescence of the hydroxamate coumarin fluorophore was almost completely quenched on coordination to the iron(III) centre in [Fe(c343haH)(3)]. However, quenching was minimal for [Fe(c343haH)(salen)] in aqueous media and we propose that the fluorescence results from structural rearrangements that occur because of the inherent strain in the iron-salen structure. Fluorescence was also measured in the presence of the cellular reductants ascorbic acid and cysteine. Fluorescence intensity increased over time, with the most rapid return of fluorescence occurring over a two hr period. The rapid fluorescence return indicates that the complexes undergo ligand release, either via reduction followed by aquation, or via direct ligand exchange with the reductants. Electrochemical studies demonstrated that both complexes have very negative reduction potentials. Furthermore, [Fe(c343haH)(salen)] was shown to exhibit quasi-reversibility of reduction. The distribution of the free hydroxamate ligand and the complexes were monitored in A2780 cells. The free ligand displayed non-specific distribution, which differed from the nucleolar distribution of [Fe(c343haH)(3)] and the lysosomal accumulation of [Fe(c343haH)(salen)] over time. Thus the results of the present study show that iron(III) complexes present a viable model for monitoring hydroxamate fluorophore displacement in vitro to determine the fate of prodrugs.

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Absorption and fluorescence spectra of 7-aminocoumarin derivatives

Cited by 20 publications

References 10 publications

Investigations using fluorescent ligands to monitor platinum(iv) reduction and platinum(ii) reactions in cancer cells

Investigations using fluorescent ligands to monitor platinum(iv) reduction and platinum(ii) reactions in cancer cells

Synthesis and spectral properties of new fluorescent hydrazone disperse dyes and their dyeing application on polyester fabrics

Iron(iii) complexes of fluorescent hydroxamate ligands: preparation, properties, and cellular processing

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