Xu Yizhuang

Hofmeister Ion Series and Its Mechanism of Action on Affecting the Behavior of Macromolecular Solutes in Aqueous Solution

Hofmeister ion series is ubiquitous and turns up frequently in many chemical and biological processes. The explanations for its mechanism of action on target macromolecules in aqueous solutions fall into two categories. The first one states that ions affect the behavior of macromolecular solutes in the aqueous solution by interacting with water, while the other one claims that direct interactions between ions and macromolecules are the key point for comprehending the Hofmeister ion series. In this paper, research works on the two mechanisms of action are elaborately reviewed. In fact, actual solution systems are inevitably complicated by rather delicate balance of all the interactions (e. g., water-water, water-ion, water-solute, ion-solute, cation-anion) and the above mentioned two viewpoints explain the Hofmeister ion series just from one side. More work is still needed to dig into the secret behind the Hofmeister ion series.

On the Tributylphosphate-Based Super-Concentrated HCl System

We reported a new super-concentrated hydrochloric acid system prepared by using tri-n-butyl phosphate (TBP)-constructed reversed micelles at ambient temperature and pressure. According to the titration result, the molar ratio of H+ to H2O (denoted as n(H)+/nH(2)O) in the super-concentrated HCl range from 0. 50 to 1. 50 which are higher than that in saturated aqueous HCl bulk solution (0. 28). Significant a moment of hydrochloric acid is confined in W/O reversed micelles. Therefore, the behavior and status of HCl are different from those of conventional bluk solution. FTIR spectroscopic results demonstrate that a significant amount of HCl remains in the molecular form rather than being ionized into H+ and Cl-. Thus, super-concentrated HCl provides an extraordinary chemical environment which may have significant influence on certain substances. We found that the color of the solution is reddish brown when copper ion is dissolved in super-concentrated HCl, while the color of the saturated HCl aqueous solution (37 Wt%) containing copper ion is green. That is to say, the copper ions exist in a special state under the unique chemical environment of super-concentrated HCl. UV-Vis-NIR spectra indicate that both d-d transition band and charge transfer transition band of copper ions in super-concentrated HCl solution underwent significant variations. In addition, copper ions also have obvious influence on the hydrogen bond network among HCl in the super-concentrated HCl solution. Remarkable variation is introduced in the H-Cl stretching band in FTIR spectra.

Enhanced brightness of Eu3+ complex in organic electroluminescent devices by using another rare-earth ion

Rare-earth ions Tb3+ and La3+ were used as a bridge to improve the energy transfer from the polymer to an Eu complex. The material Tb(La)0.5Eu0.5(BSA)3phen was synthesized and used as the emission layer in the device: ITO/PVK:Tb(La)0.5Eu0.5(BSA)3phen/Alq/Al. The two device were compared in detail and it was found that the device using La0.5Eu0.5(BSA)3phen as the emission material had better monochromatic characteristics with the maximal brightness of 102 cd/m2 and the colour coordinates x = 0.55 and y = 0.36.