Crystal, molecular and electronic structure of N,N'-diphenyl-N,N'-bis(2,4-dimethylphenyl)-(1,1'-biphenyl)-4,4'-diamine and the corresponding radical cation.

Oxidation of N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD, 1 a) and N,N'-diphenyl-N,N'-bis(2,4-dimethylphenyl)-(1,1'-biphenyl)-4,4'-diamine (1 b) with SbCl(5) affords the corresponding radical cations quantitatively. The crystal and molecular structure of 1 b and [1 b]SbCl(6), the first tetraphenyl benzidene derivatives to be characterised crystallographically in both the neutral and radical cation states, reveal molecular parameters in agreement with the predictions made on the basis of DFT studies. Analysis of the NIR transition in the radical cations [1](+) (.

SERRS dyes. Part I. Synthesis of benzotriazole monoazo dyes as model analytes for surface enhanced resonance Raman scattering.

The synthesis of seven monoazo benzotriazole dyes for use in surface enhanced resonance Raman scattering, SERRS, is reported. The dyes are all capable of complexing to the silver surface used to provide the surface enhancement found in SERRS and hence act as 'model' analytes. One dye was examined in detail and showed a quantitative relationship between concentration and signal intensity.