Electron paramagnetic resonance study of transition-metal-ion impregnated brookite titanium dioxide powders

1989 ◽  
Vol 85 (12) ◽  
pp. 4031 ◽  
Author(s):  
Angelo Amorelli ◽  
Jeffrey C. Evans ◽  
Christopher C. Rowlands
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Titanium Dioxide ◽  
Transition Metal ◽  
Metal Ion ◽  
Electron Paramagnetic Resonance Study ◽  
Paramagnetic Resonance ◽  
Transition Metal Ion ◽  
Electron Paramagnetic

Dense-shell glycodendrimers: UV/Vis and electron paramagnetic resonance study of metal ion complexation

2009 ◽  
Vol 466 (2117) ◽  
pp. 1489-1513 ◽  
Author(s):  
Dietmar Appelhans ◽  
Ulrich Oertel ◽  
Roberto Mazzeo ◽  
Hartmut Komber ◽  
Jan Hoffmann ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Metal Ion ◽  
Electron Paramagnetic Resonance Study ◽  
Copper Metabolism ◽  
Paramagnetic Resonance ◽  
Fifth Generation ◽  
Vis Spectroscopy ◽  
Dense Shell ◽  
Biological Environment ◽  
Electron Paramagnetic

The development of dendritic metal ion carrier systems for use in a biological environment is a challenging task as the carrier system must possess multiple features (e.g. a protective shell for metal decomplexation, targeting functions, metal–intradendrimer complexes, etc.) to substitute for the function of metal proteins in processes such as copper metabolism. Thus, Cu(II) complexation by a series of poly(propyleneimine) glycodendrimers ranging up to the fifth generation that have either a dense maltose or maltotriose shell was investigated by UV/Vis spectroscopy and electron paramagnetic resonance (EPR). As a necessary step towards potential biological application, we elucidated the complexation capacity, location of the Cu(II)–dendrimer complexes and the Cu(II) coordination sphere in the dendritic environment. A generation-dependent Cu(II) complexation was found. Furthermore, analysis of the EPR spectra revealed that internal and external Cu(II) coordination and the symmetry (axial and rhombic) of the generated complexes depend on the oligosaccharide shell, dendrimer generation and the relative concentrations of Cu(II) and the dendrimers. Both axial and rhombic symmetries are generation dependent, but also distort with increasing generation number. External coordination of Cu(II) is supported by sugar groups and water molecules. Finally, a third-generation dendrimer with a maltose shell was used to explore the general complexation behaviour of the dendritic poly(propyleneimine) scaffold towards different metal ions [Cu(II), Ag(I), VO(IV), Ni(II), Eu(III) and UO 2 (VI)].

Sign in / Sign up

Export Citation Format

Share Document