Metal Complexes of Nicotine: A Group of Negligible Compounds

Nicotine (NIC) is an oxygenic alkaloid compound exists in two forms R and S, and consists of a pyridine ring, substituted at the 3-position with an N-methyl-pyrrolidine ring. Nicotine is extracted mostly from the Nicotiana tabacum plant, and although it was made in the roots and accumulates in smaller amounts in leaves of edible plants of the nightshade family called “Solanaceae’’ such as tomatoes, potatoes, green peppers, and coca plants. Biochemically, it’s parasympathomimetic, stimulant drug, and is a nicotinic acetylcholine receptor agonist. It functions as an antiherbivore, insecticide, imidacloprid, and recently chromatin-modifying enzymes inhibitor. Nicotine was considered to be one of the most biologically important compounds, for which information about their metal ions complexation properties are very rare in the literature. However, recently it gains much attention from many bioinorganic chemists over the world. In the present mini review article, I described the research done during the last few decades about the solid chemistry of nicotine and studies concerning a number of crystal structures of nicotine complexes. Also, I reported about the rare research work done previously about the protonation and complexation equilibria studies of nicotine in which the data of the different equilibrium constants and stability constants of nicotine would be valued in metal based drug research. Graphical Abstract: Molecular Structure of Nicotine ((S)/(R)-3-(1-Methylpyrrolidine-2-yl) pyridine, NIC).