No abstract

New porphyrin/4-oxoquinoline conjugates were synthesized and shown to be excellent photosensitizing agents in the inactivation of S. aureus by the antimicrobial photodynamic therapy protocol.

No abstract

No abstract

4-quinolones derivatives can present fluorescent properties, depending on their substituents and on the chemical environment (e.g., acidic medium), allowing their application as ion sensors. We theoretically evaluated the photophysical properties of previously synthesized 3-acyl-4-quinolones to verify how different substituents (R1=H, NH2 and R2 = OEt, OH, NHPh) affect their absorption profiles and the emission profile of a reference compound, PB3. All DFT and TD-DFT calculations were performed at B3LYP-D3/6-311++G(d,p) level and continuum polarization model for simulated acetonitrile as solvent. For PB2 (R1 = H, R2 = OEt), we observed hypsochromic shift compared to PB3 due to the increase of the gap between HOMO/LUMO (absence of electron-donating group), in accordance with experimental data. For R1=NH2 and R2=OH, NHPh (PB6 and PB10, respectively), the gap between HOMO/LUMO increases, resulting in a soft bathochromic shift for the simulated absorption spectra. In addition, we evaluated the effect of acid addition on the absorption and emission profile of PB3 and the results were compared with experimental data. Our thermodynamic results suggest that protonation occurs on the endocyclic carbonyl of the quinolone moiety, probably due to an increased aromatic character, as suggested by our NICS calculations. Finally, we associate the increase of the fluorescence in the acidic medium to the establishment of an intramolecular hydrogen bond and, thus, increased rigidity.