Plasmon induced and pH controlled semiconductive conformation of 1H-2(phenylazo) imidazole on silver nanoparticles

A pH controlled SERS study of 1H-2(phenylazo) imidazole (PaiH) is reported. A combination of different conformations is evident; majority preferring a particular conformation at a given pH. PaiH is in cis-form at concentrations 10−6–10−5 M at pH = 7 which undergoes azo to hydrozone conformation in alkaline pH whereas the azo-Ns participate in the electronic interaction at acidic pH. Significant reduction of HOMO–LUMO gap indicates the possibility of PaiH of being an organic semiconductor.