The photophysical properties of the fluoroquinolone antibiotic moxifloxacin (MOX) were investigated in aqueous media. MOX in water, at pH 7.4, shows two intense absorption bands at 287 and 338 nm (epsilon = 44,000 and 17,000 dm(3) mol(-1) cm(-1), respectively). The absorption and emission properties of MOX are pH-dependent, pK(a) values for the protonation equilibria of both the ground (6.1 and 9.6) and excited singlet states (6.8 and 9.1) of MOX were determined spectroscopically. MOX fluoresces weakly, the quantum yield for fluorescence emission being maximum (0.07) at pH 8. Phosphorescence from the excited triplet state in frozen ethanol solution has a quantum yield of 0.046. Laser flash photolysis and pulse radiolysis studies have been carried out to characterize the transient species of MOX in aqueous solution. On laser excitation, MOX undergoes monophotonic photoionization with a quantum yield of 0.14. This leads to the formation of a long-lived cation radical whose absorption is maximum at 470 nm (epsilon(470) = 3400 dm(3) mol(-1) cm(-1)). The photoionization process releases hydrated electron which rapidly reacts (k = 2.8 x 10(10) dm(3) mol(-1) s(-1)) with ground state MOX, yielding a long-lived anion radical with maximum absorption at 390 nm (epsilon(390) = 2400 dm(3) mol(-1) cm(-1)). The cation radical of MOX is able to oxidize protein components tryptophan and tyrosine. The bimolecular rate constants for these reactions are 2.3 x 10(8) dm(3) mol(-1) s(-1) and 1.3 x 10(8) dm(3) mol(-1) s(-1), respectively. Singlet oxygen sensitized by the MOX triplet state was also detected only in oxygen-saturated D(2)O solutions, with a quantum yield of 0.075.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1111/j.1751-1097.2007.00269.x | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Investigation of mono-nuclear cobalt(II) complexes with a tri-dentate quinoxalyl-hydrazone ligand for their potential in biological research and interaction with ct-DNA.
Int J Biol Macromol
December 2024
Department of Chemistry, Faculty of Science, Sohag University, Sohag, -82534, Egypt; Department of Chemistry, College of Science, King Faisal University, P.O. Box 400, Al-Ahsa 31982, Saudi Arabia. Electronic address:
The condensing reaction of 2-hydroxy-1-naphthaldehyde with quinoxalyl-2-carbohydrazide resulted in synthesizing of a novel derivative of hydrazone quinoxalyl ligand (Hdpq). The bonding behavior between Hdpq and Co(II) ion was investigated in molar ratios of 1: 1 and 2: 1 to produce two different complexes, Codpq and Co(dpq), respectively. Their chemical structure was verified using several spectroscopic approaches.
View Article and Find Full Text PDFA novel chromogenic system for the liquid-liquid extraction and determination of trace amounts of tungsten(VI) was investigated. The system comprises 4-nitrocatechol (4NC) as a chromogenic reagent, sulfuric acid as a complexing medium, and benzalkonium chloride (BAC) as a source of bulky cations (BA+), which readily form chloroform-extractable ion-association complexes. The impact of foreign ions and reagents was studied, and the optimal conditions for the sensitive, selective, and inexpensive determination of tungsten(VI) were identified.
View Article and Find Full Text PDFMononuclear high-spin iron(III) phthalocyanines.
J Inorg Biochem
January 2025
Faculty of Textile Science and Technology, Shinshu University, Ueda 386-8567, Japan. Electronic address:
Article Synopsis
- Two iron-based compounds, FeTDPc and FeODPc, were synthesized and found to remain in a high-spin state when dissolved in various organic solvents, including chloroform and benzene.
- These compounds react with strong bases to form mono- and di-base complexes, which shift their spin states: mono-adducts become low-spin trivalent iron, while di-adducts are low-spin bivalent iron.
- When combined with specific electrolytes like tetrabutylammonium chloride, the compounds change from high-spin to low-spin states, but in solid form, a mixture of high-spin and intermediate-spin states is observed; interestingly, the iron(II) signals vanish when the compounds are isolated in pol
Substituent effect on the chemical and biological properties of diisatin dihydrazone Schiff bases: DFT and docking studies.
Comput Biol Chem
December 2024
Department of Chemistry, College of Science, King Faisal University, P.O. Box 400, Al-Ahsa 31982, Saudi Arabia; Chemistry Department, Faculty of Science, Zagazig University, Zagazig 44519, Egypt. Electronic address:
According to the considered role of lipophilicity-hydrophobicity on organic Schiff base hydrazones, different substituents of phenyl, ethyl, and methyl groups were inserted in the synthetic strategy of diisatin dihydrazones (L1-4). The biochemical enhancement was evaluated depending on their inhibitive potential of the growth power of three human tumor cells, fungi, and bacteria. The biochemical assays assigned the effected role of different substituents of phenyl, ethyl, and methyl groups on the effectiveness of their diisatin dihydrazone reagents.
View Article and Find Full Text PDFRapid spectrophotometric determination and extraction of platinum(IV) from pharmaceuticals assisted by 2-(2-(1-(thiophene-2-yl) ethylidene) hydrazinyl) benzoic acid (TEHBA).
Anal Sci
September 2024
Pravara Medical Trust's Arts, Commerce and Science College, Shevgaon, Ahmednagar, MS, 414502, India.
It has been suggested that the chelating agent 2-(2-(1-thiophene-2-yl) ethylidene) hydrazinyl) benzoic acid (TEHBA) be utilized to extract, separate and measure platinum(IV) by UV-visible spectrophotometry at the microgram level. Following 5 min of heating the reaction mixture in a water bath, Pt(IV)-TEHBA complex formed. This complex was formed in the presence of potassium iodide solution with a molar absorption coefficient 1.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!