Synthesis and characterization of new mercury(II) complexes derived from α-keto stabilized new pyridinium ylide

Metal carbene complexes are of much interest in synthetic chemistry [1]. One of the most abundant carbene complexes are Cα coordinated Hg(II) complexes. Pyridineylides R2N=C(R′)(R″) (R, R′, R″=alkyl or aryl groups) are very reactive species with interesting applications in organic synthesis [2]. These compounds can behave as ambidentate ligands, because the carbanion located at the Cα of the ylide or the enolate oxygen is able to donate electron density to a transition metal [3]. Considering the importance of metal carbenes, and particularly pyridinium ylide, synthetically simple and general routes for their preparation are highly desirable. Herein, we report the synthesis and characterization of new binuclear and polymeric complexes of Hg(II) derived from α-keto stabilized pyridinium ylide. Reaction of α- keto stabilized pyridinium ylides C6H5NCHC(O)C6H4R (R=m-CN) with HgX2 (X= Cl, Br, I) in 1:1 ratio leads to binuclear products of the type [HgX2(ylide)]2. Also, polymeric products of the type [(ylide)Hg(NO3)2]n obtained by the reaction of mentioned ylide and Hg(NO3)2 in 1:1 ratio. The reaction yielded the desired Hg(II) complexes in excellent yields. Characterization of the complexes by IR, 1H and 13C NMR spectroscopy confirmed coordination of the ylide to the metal through the carbon atom (Fig. 1).