W. E. Smith

The vibrational properties of some gold(III)-halide complexes

Raman and i.r. spectra of a range of gold complexes of the form LAuX3 (L = C6H5)3P, (C2H5)3P, pyridine, lutidene and α-picoline; X = Cl− or Br−) are reported and interpreted on the basis of a C2ν symmetry for the molecules. The effects of changes in the electronic structure appear to have a larger influence on the vibrational spectrum than steric or mass effects. The splitting of ν6(D4h) resulting from substitution by L is much larger in the bromide series than in the chloride series and is probably due to π bonding in the complexes. ν1 and ν2 energy changes reflect both a change in bonding and in a smaller mass and steric influence. The compounds Py2AuX3 appear to be trans isomers.

Resonance Raman spectroscopy of hemoglobin in intact cells: A probe of oxygen uptake by erythrocytes in rheumatoid arthritis

Resonance Raman spectra from intact viable erythrocytes can be used to study oxygen uptake in solution. In addition to changes in the oxidation state marker (nu 4), other bands due to the porphyrin ring (nu 3) and vinyl modes indicate subtle changes at oxygen pressures close to where the T/R change occurs. A comparison of whole cell and lysate spectra indicates a partial denaturation of hemoglobin on lysis. A simple smear technique is used to measure spectra from rheumatoid and normal blood. Results indicate a faster but less complete uptake of oxygen in cells from patients with rheumatoid arthritis than is the case in normal cell populations.

The vibrational properties of gold(III) chloride complexes of bipyridyl and 1,10-phenanthroline

Abstract Raman and i.r. spectra of complexes of gold(III) with chloride and bipyridyl or 1,10-phenanthroline ligands are reported. The spectra in both the aromatic-ring stretching region and the metal—halide stretching region are assigned. The compounds are four-coordinate. It is concluded that the nitrogen ligands bridge two AuCl 3 moieties in (L 2 )Au 2 Cl 6 compounds and that bipyridyl AuCl 3 is a polymer containing planar bipyridyl AuCl 2 units bridged by chloride ions.

Particle–metal interactions. A raman and electrochemical study of a compacted electrode of copper phthalocyanine and silver metal

Electrodes consisting of a compacted mixture of powders of silver metal and α copper phthalocyanine (CuPc) have been used to study the interaction between small pigment particles and a metal surface using resonance Raman spectroscopy as a probe of in situ changes. The purpose of this present paper is to explore the condition required to produce optimum enhancement.Cycling in acid sulphate or nitrate electrolytes with a sufficiently positive voltage to release silver(I) ions resulted in the formation of a thin layer of CuPc particles spread out on the metal surface. The layer formed produced an improvement in Raman scattering from CuPc. From the resonance profile it was clear that there was a significant charge transfer interaction with the metal surface. The relative intensities of the peaks in the Raman spectra are dependent on potential. As well as the possible use of such electrodes in chemistry, particle metal layers of this type provide a different starting point for studies of the surface enhanced resonance Raman effect emphasising the electromagnetic contribution rather than the chemical one.

Resonance enhancement of the Raman spectrum of bipyridyl gold(III) chloro complexes

Using exciting wavelengths in the visible region, both bipyridyl Au2Cl6 and bipyridyl AuCl3 are shown to exhibit resonance-enhanced Raman scattering. The enhancement in bipyridyl Au2Cl6 is largest with 488.0 and 514.5 nm excitation, both bipyridyl ring and metal-ligand stretching vibrations are affected to about the same extent. The electronic transitions which give rise to the enhancement are assigned as transitions involving σ molecular orbitals delocalized over the complete molecule. In the resonance profile of bipyridyl AuCl3, there were three peaks at 568.2, 514.4 and below 476 nm and, in addition, there is a probable B term enhancement. In this molecule the resonance arises from transition between more localized molecular orbitals assigned as due to a transition on the gold-nitrogen bond, to π→π* transitions on the bipyridyl ring and the B term to a transition located mainly on the gold-chloride bonds. Some of these enhancements can be correlated with weak structure observed in the 10 K absorption spectrum of the complex.

Resonance raman-spectra produced by the reaction of 5,5'-dithiobis(2-nitrobenzoic acid) with glutathione and with sulfhydryl-groups of biological-fluids

This paper discusses resonance raman-spectra produced by the reaction of 5,5-dithiobis(2-nitrobenzoic acid) with glutathione and with sulfhydryl-groups of biological-fluids.