Molecular-Enhanced Raman Spectroscopy Driven by Phosphoester Electron-Transfer Bridge

Althoughboth electromagnetic and charge transfer (CT) mechanismsplay a role in surface-enhanced Raman scattering (SERS), the contributionof the latter is limited by poor CT efficiency. Herein, we proposemolecular-enhanced Raman spectroscopy (MERS) for the first time anddevelop a simple strategy to induce strong CT-enhanced Raman signalsusing a phosphoester (POE) electron-transfer bridge. Consequently,an excellent POE-enhanced Raman effect was found when various mono-,bis-, and trisaminobenzene compounds were used as probe analytes.Quantification analysis of this MERS effect revealed that the enhancementratio and factor of the POE molecules can be up to 87% and & SIM;10(9), respectively. Spectroscopic analysis and density functionaltheory calculation confirmed that this effect was because of the formationof intermolecular hydrogen bonds, which promotes CT via electronicreorganization and enhances the Raman signals of target analytes.These results demonstrate the feasibility of MERS for highly CT-enhancedRaman signals.

Automated summary

Although both electromagnetic and charge transfer mechanisms play a role in surface-enhanced Raman scattering (SERS), the contribution of charge transfer is limited by poor efficiency. This study introduces molecular-enhanced Raman spectroscopy (MERS) and demonstrates a simple strategy to achieve strong charge transfer-enhanced Raman signals using a phosphoester electron-transfer bridge. The results show that MERS can significantly enhance Raman signals and offer a potential solution for highly charge transfer-enhanced Raman signals.