The Schiff-base (PNOAAP) derived from picolinaldehyde N-oxide and 4-aminoantipyrine, and its copper(Ⅱ) complex: [Cu(PNOAAP)2(EtOH)2]2(ClO4)4 (1) has been prepared and characterized by elemental analysis, i.r., 1H n.m.r, spectrum, and single crystal X-ray crystallographic determination. The PNOAAP ligand isomerizes from trans to cis after chelating to copper(Ⅱ).

The interaction between Ag+ and human serum albumin (HSA) has been intensively studied by means of equilibrium dialysis, ligand-to-metal charge transition (LMCT) bands, circular dichroism (CD) and Raman spectroscopy. Scatchard analysis of the results of 1 equilibrium dialysis indicates the presence of two types of binding sites for Ag+ on HSA, and the orders of magnitude of binding stability 54 constants are found to be 10 5 and 10 4, respectively. During the binding process, a gradual increase in absorbance values of LMCT bands is observed with time-scanning UV absorption spectra, implying the Ag(Ⅰ) centers are continually formed in HSA. The time-scanning CD1 spectra provide evidence that the binding of Ag+ induces HSA to undergo a slow rearrangement of tertiary structure, and to change from 11 the original conformation in the absence of Ag (B-state) to conformation binding with Ag (A-state). The rate constants and activation free energy of A-B transition are calculated. The Raman spectrum of Ag(Ⅰ)-HSA system shows distinct vibration bands at 224 and 246 21cm in the low-frequency region, which significantly reveal the formation of Ag-S and Ag-N bonds. In addition, the electrostatic 1 interaction between Ag+ and negatively charged oxygen is also detected with Raman spectroscopy.

The binding equilibrium between phosphotungstic acid (H7[P(W2OT)6]

The binding equilibrium between I- and human serum albumin (HSA) or bovine serum albumin (BSA) has been studied by means of the resonance Rayleigh scattering (RRS) and equi librium dialysis. It has been found for the first time that RRS and multiple frequency scattering (MFS) are enhanced as the I- binding to the HSA and BSA, but fluorescence quenches. The equilibrium dialysis results suggest that the binding of I

The mechanisms and effects about the interaction between serum albumins and silver nanoparticles have been intensively studied by means of transmission electron microscopy (TEM), circular dichroism (CD) and ultraviolet-visible (UV-Vis) spectroscopy. The adsorption of serum albumins on the surface of silver nanoparticles is observed by TEM. The studies with the surface plasmon bands indicate that the electrostatic and hydrophilic interactions are the major forces between serum albumins and silver nanoparticles; the number of adsorbed monolayer serum albumin molecules to a silver nanoparticle with the size of 60nm is about 6.7