Thiocyanate electronic spectra

A -bis [2-(dimethylamino)ethyl] W -dimethyl-1 -ethanediamine] (thiocya-nato-AOpalladium(II) thiocyanate is a diamagnetic, yellow solid. It is veiy hygroscopic and ould be stored in a moisture-free atmosphere. The palladium atom is four-coordinate in the solid state. The H nmr spectmm in DjO exhibits 2 singlet resonances at 2.56 and 2.63 ppm for the methyl protons (DSS as reference). The electronic spectrum in H2O is characterized by 2 absorption maxima at 263 run (e = 7200 L mole cm ) and 325 nm (e = 1800 L mole cm ). The infrared spectrum (Nujol) exhibits i CN) bands at 2105 and 2060 cm. ... 

The lowest energy MLCT transition of Ru polypyridyl complexes of the type tris-[Ru(4,4/-dicarboxy-2,2/-bipyridine)3] (1), can be lowered so that it absorbs more in the red region of the visible spectrum by replacing one 4,4/-dicarboxy-2,2/-bipyridine (dcbpy) with two thiocyanate donor ligands [Ru(dcbpy)2(NCS)2] (2). In complex 2, the two 4,4/-dicarboxylic acid 2,2 -bipyridine ligands pull while the two thiocyanate donor ligands push electrons. The oxidation potential of the complex 2 is 0.85 V vs. SCE, which is cathodically shifted significantly (0.65 V vs. SCE) compared to the homoleptic type of complex 1, which shows Ru(III/II) couple at 1.5 V vs. SCE. Thus, the... 

Since the intensity of the electron adduct band decreases rapidly below 4000 A. the first two spectra approximate to those of the H atom and OH radical adducts, while the third represents the difference between them. The qualitative conclusions drawn from visual examination of the gross spectra are confirmed the H atom adduct spectrum reaches a peak at —3900 A. compared with —3600-3800 A. for the much broader, less intense OH radical adduct spectrum, while the negative values of ge(e0H-ee) above 3900 A. suggest that the electron adduct spectrum extends a little below 4000 A., although its intensity is much less than that of the H atom adduct. From the measured dose in the pulse, calibrated against thiocyanate, and assuming the primary yields to be g(OH) = 2.9, g(H) = 0.6, g(e aq) = 2.3, we calculate the following approximate values for the extinction coefficients of the transients ... 

Reaction of K2[OsCl6] and KSCN with precipitation of the products by (Bu"4N)+ yields (Bu"4N)3[Os(NCS)j] IR, electronic absorption and Mossbauer spectra were measured, and the magnetic susceptibility was measured from 90 to 295 K (ji,g = 1.78 BM at 295 K). On the basis of the IR spectrum in particular no clear conclusion could be drawn as to whether the thiocyanate ligand was N or S bonded. Subsequent investigation showed that a mixture of isomers (Bu"4N)j[Os(NCS) (SCN)6 ] is formed in the reaction, " and these may be separated by high-voltage electrophoresis or ion exchange. ... 

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