Novel optical/electrochemical selective 1,2,3-triazole ring-appended chemosensor for the Al3+ ion.

Developments in the field of fluorescent chemosensors for trace level determination of Al3+ have been described. Design, synthesis and applications of Al3+ selective fluorescent sensors have attracted a great deal of attention due to their versatile and emerging biological implications. A systematic description of different fluorescent probes based on their fluorophore skeleton has been made. The sensing mechanism of each fluorescent probe has been briefly discussed. Special emphasis has been given to consideration of the greenness of the methods, particularly, the use of greener solvents like water. The review covers published work on fluorescence sensing of Al3+ worldwide together with our own contribution in this field.

Fluorescent probes for selective determination of trace level Al3+: recent developments and future prospects

Highly palatable diet consumption increases protein oxidation in rat frontal cortex and anxiety-like behavior.

Deactivation pathways of electronically excited states have been investigated in three protonated aromatic amino acids: tryptophan (Trp), tyrosine (Tyr) and phenylalanine (Phe). The protonated amino acids were generated by electrospray and excited with a 266 nm femtosecond laser, the subsequent decay of the excited states being monitored through fragmentation of the ions induced and/or enhanced by another femtosecond pulse at 800 nm. The excited state of TrpH+ decays in 380 fs and gives rise to two channels: hydrogen atom dissociation or internal conversion (IC). In TyrH+, the decay is slowed down to 22.3 ps and the fragmentation efficiency of PheH+ is so low that the decay cannot be measured with the available laser. The variation of the excited state lifetime between TrpH+ and TyrH+ can be ascribed to energy differences between the dissociative πσ* state and the initially excited ππ* state.

Ultrafast deactivation mechanisms of protonated aromatic amino acids following UV excitation

Effects of protein malnutrition on oxidative status in rat brain

Photophysical properties of tyrosine at low pH range

Three newly synthesized polyanthraquinone derivatives: 7,13-bis(9,10-dioxo-1-anthryl)-1,4,10-trioxa-7,13-diazacyclopentadecane, (AQ)A215C5, 7,16-bis(9,10-dioxo-1-anthryl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane, (AQ)A218C6, and tris[(9,10-diokso-1-antryl)-aminoethyl]amine, (AQNet)3N, were examined by cyclic and normal pulse voltammetry All anthraquinone groups in these compounds were electroactive and formed the radicals and dianions similarly to simple anthraquinone The differences between the voltammograms obtained in the absence and presence of supporting electrolyte are discussed, and the diffusion coefficients of the compounds and the rates of the chemical reactions following the first reduction step were evaluated (AQNet)3N appears to be a good model compound for multi electron transfers in aprotic solvents It offers two consecutive nearly reversible 3-electron redox systems: 0/−3 and −3/−6 The interactions of the radicals and dianions of the above compounds with alkali metal cations were examined

Supramolecular Derivatives of 9,10‐Anthraquinone. Electrochemistry at Regular‐ and Low Ionic Strength and Complexing Properties

The influence of Li+, Na+, K+, Cs+, Mg2+, Ca2+, Sr2+, Ba2+, Co2+, Ni2+, Cu2+, Zn2+, Pb2+ and Al3+ ions on the spectroscopic properties of the dansyl group covalently linked to crown ether or diazacrown ethers was investigated by means of absorption and emission spectrophotometry. Interaction of the alkali metal ions with all fluoroionophores studied is weak, while alkaline earth metal ions interact strongly causing about 50% quenching of dansyl fluorescence of A21C5-Dns and A218C6-Dns. The Cu2+, Pb2+ and Al3+ cations interact very strongly with dansyl chromophore regardless the crown ether type, causing a major change in absorption spectrum of the chromophore and forming non-fluorescent complexes. The Co2+, Ni2+, Zn2, Mg2+ and Ag+ cations interact moderately with all fluoroionophores studied causing about 20% of fluorescence quenching of dansyl, except for a strong dansyl fluorescence quenching of 15C5-Dns by Co2+ ion. The quenching efficiency of didansylated fluoroionophores by the alkali metal ions and alkaline earth metal ions is weaker than monodansylated ones.

Synthesis and fluorescence behaviour of crown and azacrown ethers carrying the dansyl fluorophore as a pendant in acetonitrile solution

Formation of complexes of A18C6-Dns and metal cations (Ca2+, Sr2+, Ba2+ and Mg2+) in acetonitrile has been studied by NMR, absorption and fluorescence spectroscopy and PM5 semi-empirical methods. A18C6-Dns forms stable complexes with Ca2+, Sr2+ and Ba2+ cations. The stability constants of various complexes are determined by different methods and their structures are visualised by the PM5 semi-empirical calculations.

1H NMR and spectrophotometric study of alkaline metal ion complexes with N-dansyl aza-18-crown-6

The inﬂuence of Li + ,Na,K + ,Cs,Mg 2 ,Ca 2+ ,Sr 2+ ,Ba 2 ,Co,Ni,Cu,Zn,Pb 2 + and Al 3 ions on the spectroscopicproperties of the dansyl group covalently linked to crown ether or diazacrown ethers was investigated by means of absorption and emissionspectrophotometry. Interaction of the alkali metal ions with all ﬂuoroionophores studied is weak, while alkaline earth metal ions interactstrongly causing about 50% quenching of dansyl ﬂuorescence of A21C5-Dns and A 2 18C6-Dns. The Cu 2+ ,Pb 2+ and Al 3+ cations interactvery strongly with dansyl chromophore regardless the crown ether type, causing a major change in absorption spectrum of the chromophoreandformingnon-ﬂuorescentcomplexes.TheCo 2+ ,Ni ,Zn 2 ,Mg andAg + cationsinteractmoderatelywithallﬂuoroionophoresstudiedcausing about 20% of ﬂuorescence quenching of dansyl, except for a strong dansyl ﬂuorescence quenching of 15C5-Dns by Co 2+ ion. Thequenchingefﬁciencyofdidansylatedﬂuoroionophoresbythealkalimetalionsandalkalineearthmetalionsisweakerthanmonodansylatedones. © 2002 Elsevier Science B.V. All rights reserved.

Short communication Synthesis and fluorescence behaviour of crown and azacrown ethers carrying the dansyl fluorophore as a pendant in acetonitrile solution

Hanna Sulowska

Papers

Photophysical properties of tyrosine at low pH range

Supramolecular Derivatives of 9,10‐Anthraquinone. Electrochemistry at Regular‐ and Low Ionic Strength and Complexing Properties

Synthesis and fluorescence behaviour of crown and azacrown ethers carrying the dansyl fluorophore as a pendant in acetonitrile solution

1H NMR and spectrophotometric study of alkaline metal ion complexes with N-dansyl aza-18-crown-6

Short communication Synthesis and fluorescence behaviour of crown and azacrown ethers carrying the dansyl fluorophore as a pendant in acetonitrile solution