Surface Enhanced Resonance Raman Spectra of a Model Molecule for Boron Dipyrromethene Dyes

Boron dipyrromethene dyes attract steadily growing interest as therapeutic and diagnostic tools. Therefore, their ground-state vibrational spectra deserve special attention. Resonance Raman spectroscopy can be advantageously exploited to rationally understand the vibrational properties of molecular chromophores. Interference from fluorescence should be avoided if detailed measurements are to be performed. We have obtained resonance Raman spectra of a model molecule for boron dipyrromethene dyes through a judicious choice of the sample and the measurement conditions. These included spectra at the solid state and surface-enhanced spectra on dispersed silver nanoparticles. The results can form the basis for the interpretation of the spectral features of related dyes bearing complex chemical substituents.