Vanadium K-edge X-ray-absorption spectra were collected for samples of thionine-oxidized, super-reduced (during enzyme turnover) and dithionite-reduced VFe-protein of the vanadium nitrogenase of Azotobacter chroococcum (Acl*). Both the e.x.a.f.s and the x.a.n.e.s. (X-ray-absorption near-edge structure) are consistent with the vanadium being present as part of a VFeS cluster; the environment of ...

Photocatalytic properties of Ag@TiO2 composite clusters have been investigated using steady state and laser pulse excitations. Photoexcitation of TiO2 shell results in accumulation of the electrons in the Ag core as evidenced from the shift in the surface plasmon band from 460 to 420 nm. The stored electrons are discharged when an electron acceptor such as O2, thionine, or C60 is introduced int...

The radical yield in the electron t ransfer reactions between thionine tr iplet and various halogenanilines, as measured by kinetic flash spectroscopy in the microsecond time region, decreases by application of magnetic fields up to 4 kGauss . The relative magnetic field effect parallels the influence of the heavy atom substi tuents on the intersystem crossing ra te constant in the triplet exci...

A direct electrochemical biosensing platform has been fabricated by covalent incorporation of carbon nanotubes (CNT) and gold nanoparticles (GNP) onto the poly(thionine) (PTH) film deposited by electropolymerization. With the synergic effects of the composite nanomaterials together with the excellent mediating redox polymer, the proposed platform could allow for faster electron transfer and hig...

Polarization modulation-Fourier transform infrared (PM-FTir) spectra were. obtained in situ for polymer films of neutral red and thionine, and for a lilm of leucomethylene blue generated on a gold electrode as a function of potential. The spectra of the polymer films revealed that the aromatic rings lie mostly parallel to the electrode surface in both the reduced and oxidized forms. In contrast...

We report the simple synthesis and full investigation of a novel heparin binding dye, mallard blue, an arginine-functionalized thionine. This dye binds heparin in highly competitive media, including water with high levels of competitive electrolyte, buffered aqueous solution and human serum. The dye reports on heparin levels by a significant change in its UV-vis spectroscopic profile. Molecular...