Weiqing Xu

Spectroscopy study on the photochromism of Schiff bases N,N'-bis(salicylidene)-1,2-diaminoethane and N,N'-bis(salicylidene)-1,6-hexanediamine.

The photochromism of Schiff bases N,N-bis(salicylidene)-1,2-diaminoethane (BSE) and N,N-bis(salicylidene)-1,6-cyclohexanediamine (BSH) was studied by steady-state and time-dependent fluorescence, UV Vis absorption spectroscopy and theoretical chemistry calculations. The experimental results show that BSH can perform the photochromism easier than BSE, may be due to the molecular topology difference.

Interaction of La3+ and cholesterol with dipalmitoylphosphatidylglycerol bilayers by FT-Raman spectroscopy

The interaction of La3+ and cholesterol with the negatively charged phospholipid dipalmitoylphosphatidylglycerol bilayers was studied by Fourier transform-Raman spectroscopy. La3+ was shown to increase interchain order and intermolecular ordering of the lipid lattice, cholesterol exhibited less of an effect, the La3+-DPPG-cholesterol complex was more ordered than cholesterol=DPPG nd less ordered than La3+-DPPG complexes, cholesterol modulates the order/disorder parameters of DPPG bilayers.

Study on the molecular orientation of an anti-ferroelectric liquid crystal by two-dimensional correlation polarized infrared spectroscopy

Polarization-dependent infrared spectra of an antiferroelectric liquid crystal in the phase were measured at 60°C, for investigation of the relative orientation of the terminal alkyl chain and mesogen. The polarization angle-dependent infrared spectra obtained were analysed by two-dimensional (2D) correlation spectroscopy. The orientation of the mesogen segment and the alkyl chains in the phase is similar to that in the SmC* phase. Four new CH3 and CH2 stretching modes were observed from the 2D correlation spectra. From these we can clearly separate the vibrational mode for two hydrocarbon chains and conclude that the orientations of the two chains are different. The C=O group adjacent to the chiral segment is also separated by 2D correlation spectra into two bands, which may arise from either the C=O group hydrogen-bonded with the phenyl ring, or from another rotational conformation of the molecule.

Spectroscopic study on the photochromism of Schiff base N -salicylidene-α-methylbenzylamine

The photochromism of Schiff base N-salicylidene-α-methylbenzylamine has been studied by time-dependent UV–Vis absorption and fluorescence spectroscopy.

Direct measurement of the photochromism kinetics of salicylideneamines in solid state

A method for the study of photochromism kinetics of salicylideneamines in the solid state with fluorescence changes as the probe was described. This can be used to quantitatively evaluate the photochromism of some solid photochromic materials.

Aggregation Behavior of Azoanthracene Compounds in Solution

Abstract Aggregation of azoanthracene compounds 10-(4-carboxylphenylazo)-9-anthranol and 10-(2-carboxylphenylazo)-9-anthranol in solution was investigated by UV-vis spectroscopy. It was determined that the forming of a hydrogen bond, either intermolecular or intramolecular, can affect the wavelength of π-π* transition absorption. Using this principle the aggregation state of azoanthracene compounds was characterized.