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Updated: Aug 4, 2025

Raman and IR Spectroelectrochemical Methods as Tools to Analyze Conjugated Organic Compounds
Published on: October 12, 2018
Stretching the Bisalkyne Raman Spectral Palette Reveals a New Electrophilic Covalent Motif
Manasa Punaha Ravindra1, Martin Lee2, Silviya Dimova2
1School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, UK.
Abstract:
Small heteroaryl-diyne (Het-DY) tags with distinct vibrational frequencies, and physiologically relevant cLog P were designed for multiplexed bioorthogonal Raman imaging. Pd-Cu catalyzed coupling, combined with the use of Lei ligand, was shown to improve overall yields of the desired heterocoupled Het-DY tags, minimizing the production of homocoupled side-products. Spectral data were in agreement with the trends predicted by DFT calculations and systematic introduction of electron- rich/poor rings stretched the frequency limit of aryl-capped diynes (2209-2243 cm-1 ). The improved Log P of these Het-DY tags was evident from their diffuse distribution in cellular uptake studies and functionalizing tags with organelle markers allowed the acquisition of location-specific biological images. LC-MS- and NMR-based assays showed that some heteroaryl-capped internal alkynes are potential nucleophile traps with structure-dependent reactivity. These biocompatible Het-DY tags, equipped with covalent reactivity, open up new avenues for Raman bioorthogonal imaging.
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