A selective fluorescent 'turn-on' sensor for recognition of Zn(2+) in aqueous media.

A new rhodamine-based fluorescent probe 'RhAP' was synthesized and successfully characterized using FT-IR, (13)C NMR and (1)H NMR spectroscopies, LC-MS/MS spectrometry and elemental analysis. The RhAP, a colorless and non-fluorescent compound, showed a selective fluorescent response and colorimetric change for Zn(2+) in HEPES buffer (10mM, EtOH:water, 2:1, v/v, pH7.2). Upon the addition of two equivalents of Zn(2+) to a solution of RhAP, a nearly 35-fold enhancement of the fluorescence intensity, with an emission maximum at 578 nm, was observed in comparison to the sensor alone under the same experimental conditions. The complex formation between RhAP and Zn(2+) was found to have a 1:1 ratio based on calculations obtained from Job's plot and the mole ratio plot methods. The results showed that RhAP can be used as an effective fluorescent probe for selective detecting of Zn(2+) in an aqueous medium.

A novel one-pot synthesis of heterocyclic compound (4-benzoyl-5-phenyl-2-(pyridin-2-yl)-3,3a-dihydropyrazolo[1,5-c]pyrimidin-7(6H)-one): structural (X-ray and DFT) and spectroscopic (FT-IR, NMR, UV-Vis and Mass) characterization studies.

In this study, the title compound named as 4-benzoyl-5-phenyl-2-(pyridin-2-yl)-3,3a-dihydropyrazolo[1,5-c]pyrimidin-7(6H)-one (C24H18N4O2) was both experimentally and theoretically investigated. The compound was synthesized and characterized by FT-IR, NMR ((1)H NMR, (13)C NMR and HETCOR-NMR), Mass spectroscopies and single-crystal X-ray diffraction methods. The compound crystallizes in the monoclinic space group P2(1)/n with a=6.1402 (3) Å, b=21.4470 (15) Å, c=15.0049 (8) Å and ß=97.407 (4)°. The molecular geometry was obtained from the X-ray structure determination optimized using density functional theory (DFT/B3LYP) method with the 6-31+G(d, p) basis set in ground state. From the optimized structure, geometric parameters, vibrational wavenumbers and chemical shifts of molecule were obtained. Experimental measurements were compared with its corresponding the calculated data. An excellent harmony between the two data was ascertained. Besides, molecular electrostatic potential (MEP), frontier molecular orbitals (FMOs) and non-linear optical (NLO) properties of the title molecule were investigated by theoretical calculations at the B3LYP/6-31+G(d, p) level.