Liguo Yang

Synergistic coupling of fluorescent "turn-off" with spectral overlap modulated FRET for ratiometric Ag+ sensor.

A useful strategy for ratiometric fluorescent detecting of Ag(+) is demonstrated. Upon selective binding of Ag(+) to a BODIPY-porphyrin dyad (1), the synergistic coupling of two functions, namely the suppressing of FRET from BODIPY donor to porphyrin acceptor and the fluorescence quenching of porphyrin acceptor, leads to exceptionally large changes in the intensity ratio of two distinct emissions (F513/F654) which allow for the ratiometric detecting of Ag(+) with excellent sensitivity in solution and living cells.

Stereochemistry and Solid-State Structure of an Intrinsically Chiral Meso-Patterned Porphyrin: Case Study by NMR and Single-Crystal X-ray Diffraction Analysis

A C1-symmerical meso-substituted ABCD-type porphyrin, [5-phenyl-10-(2-hydroxynaphthyl)-15-(4-hydroxyphenyl)porphyrinato]zinc(II) (1), has been synthesized and characterized. The molecular structure of 1 has been determined by single-crystal X-ray diffraction analysis. The complex 1 crystallizes in a triclinic system with one pair of enantiomeric molecules per unit cell. Resolution of the racemic mixture has been achieved by chiral HPLC techniques. In particular, the absolute configurations of the enantiomers have been assigned from NMR spectroscopic analysis with L-Phe-OMe as the chiral solvating agent (CSA). The assignments have also been unambiguously confirmed by single-crystal X-ray diffraction analysis. The present results suggest that the CSA-NMR anisotropy strategy is applicable for the stereochemistry determination of chiral host-guest complexes with multiple intermolecular interactions. In addition, the multiple intermolecular interactions between the enantiomerically pure porphyrin S-1 and L-Phe-OMe are proved in the solid state by single-crystal X-ray diffraction analysis.

Effects of Mn dopant on tuning carrier concentration in Mn doped ZnO nanoparticles synthesized by co-precipitation technique

Zn1 − xMnxO (x = 0.002–0.01) nanoparticles were synthesized by co-precipitation method. The detailed crystal structure and compositional characterizations were characterized by the XRD patterns, Raman spectra, XPS, HRTEM and SEM. the XRD and XPS results show the Mn2+ ions are substitute for Zn2+ ions in the ZnO matrix. In the Raman spectra, the E2(high) peak shifts to lower frequency and the higher intensity of A1(LO) peak appears in the sample with increasing doping concentrations of Mn, indicating a higher concentration of donor defects are introduced in ZnO nanoparticles. Then, the carrier concentration induced by oxygen vacancies are analyzed from the optical absorption spectra. By analyzing the O1s XPS spectrum by Lorentz fitting and PL spectra by Gaussian fitting, the oxygen vacancy concentration increases with Mn doping concentration. The present results suggest that the doped Mn2+ ions play a significant role on enhancing the carrier concentration of ZnO materials.