Synthesis, structural characterization, solid-state structures, and DNA binding studies of pseudo octahedral mercury(II)-N-heterocyclic carbene (NHC) complex

This work describes the easy synthetic approaches, structural features, and Hirshfeld surface studies of mercury (II)-N-heterocyclic carbene (NHC) complexes. The proligands 2-(pyridylmethyl)imidazo[1,5-a]pyridin-4-yliumtetrafluoroborate(1.HBF4) and 1-methyl-2-(pyridylmethyl)imidazo[1,5-a]pyridin-4-ylium tetrafluoroborate (2. HBF4) were synthesized by formylative cyclization of corresponding Schiff bases. Hg(II)-NHC complexes [Hg (1)2][BF4]2(1a) and [Hg(2)2][BF4]2(2a) were synthesized using Hg(OAc)2 under refluxing condition in acetonitrile. The compounds were characterized using various spectroscopic techniques. The UV-Vis spectra show the red shift in comparison to proligands in the case of high energy region support the formation of Hg(II)-NHC complexes. Finally, the geometry of 1a and 2a were elucidated by single crystal X-ray diffraction analyses, at least in one case (2a) leading to pseudo-octahedral geometry. Both complex 1a and 2a bind with the genomic DNA of the MCF-7 cell. The molecules possess several M-N, F-pi, C-H-F, C-H-B, etc non-covalent interactions that are also supported by Hirshfeld surface analysis.