Novel Polypyridyl Ruthenium(II) Complexes Containing Oxalamidines as Ligands.

The complexes [Ru(bpy)2(H2TPOA)](PF6)2 ⋅ 4H2O, (1); [Ru(Me-bpy)2(H2TPOA)](PF6)2 ⋅ 2H2O, (2); [Ru(bpy)2(H2TTOA)](PF6)2 ⋅ 2H2O, (3); [Ru(Me-bpy)2(H2TTOA)](PF6)2 ⋅ 2H2O, (4) and {[Ru(bpy)2]2(TPOA)}(PF6)2 ⋅ 2H2O, (5) (where bpy is 2,2´bipyridine; Me-bpy is 4,4´- dimethyl-2,2´-bipyridine; H2TPOA is N, N´, N´´, N´´´- tetraphenyloxalamidine; H2TTOA is N, N´, N´´, N´´´- tetratolyloxalamidine) have been synthesized and characterized by 1H-NMR, FAB-MS, infrared spectroscopy and elemental analysis. The X-ray investigation shows the coordination of the still protonated oxalamidine moiety via the 1,2−diimine unit. The dimeric compound (5) could be separated in its diastereoisomers (5´) and (5´´) by repeated recrystallisation. The diastereomeric forms exhibit different 1H-NMR spectra and slightly shifted electronic spectra. Compared with the model compound [Ru(bpy)3]2+, the absorption maxima of (1)–(5) are shifted to lower energies. The mononuclear complexes show Ru(III/II)- couples at about 0.9 V vs SCE, while for the dinuclear complex two well defined metal based redox couples are observed at 0.45 and 0.65 V indicating substantial interaction between the two metal centres

Apollinaire and Cubism?

1996-01-01

FPGA applications in signal and image processing

The increasing demand for real-time and smart digital signal processing (DSP) systems, calls for a better platform for their implementation. Most of these systems (e.g. digital image processing) are highly parallelisable, memory and processor hungry; such that the increasing performance of today�s general-purpose microprocessors are no longer able to handle them. A highly parallel hardware architecture, which offers enough memory resources, offers an alternative for such DSP implementations

Reduction of a-tocopherylquinone Model Compound With Various Reductant

In order to study the possibility of tranformation of a-tocopherylquinone (TQ) into a more oxidiseable compound and also to find out the recycling effect in the cells, an experiment was conducted by reducing the model compound 2-(3- hydroxy-3-methylbutyl)-3,5,6-trimethyl-1,4-benzoquinone (PQ) with various reductants. In the experiment it was shown that glutathione did not reduce PQ,nor NADH by itself, so the effective reductant in the NADH/FAD combination must have been FADH2. Thus there is a probability that in a biological system, the most probable reductant for TQ would be a flavin enzyme rather that ascorbic acid or glutathione. The non-physiological dithiothreitol was as effective as NADH/ FAD which is interesting because of its similarity to the physiologically important reduced lipoic acid. The reactivity of the various reductants used in this experiment decrease in the order of dithiothreitol ~ NADH/FAD (8/10) > sodium dithionite > NADH/FAD (2:10) > sodium ascorbate > ascorbic acid (Fig.8)