In-situ synthesis of mercury(II)-N-heterocyclic carbene complexes by using “oxide route”, structural characterization and their photo-catalytic degradation activity for dyes

Abstract

N-alkylated imidazole derivatives (1a-1b), mono-azolium salts (SL2-SL3) and their symmetrically (SC2) and non-symmetrically (SC3) substituted mercury(II)-N-heterocyclic carbene (Hg(II)-NHC) complexes were synthesized by using “oxide route”. The characterization was done by using physical (i.e., solubility, melting point determination, compound microscopic analysis) and spectral (i.e., UV-Visible spectroscopy, FT-IR spectroscopy, 1H and 13C NMR spectroscopy) methods. Chemical equilibrium between monomeric and dimeric structures of bromide-bridging Hg(II)-NHC complexes was also observed in the presence of solvent. Photo-catalytic degradation rate of two environmentally polluting dyes i.e., methylene blue (MR) and congo red (CR), was investigated by using compound 1 (SC2) and compound 2 (SC3) which demonstrated that the compound 2 had maximum degradation rate in the range of 70–80% as compared to the compound 1 (60–70% ).