Coordination behaviour of 2-(Methylthio)Pyrazine with Ag(I) in the presence of different counter anions and emission properties

Abstract

Three new coordination polymers (CPs), [Ag(MTP)2(PF6)]n 1, [Ag(MTP)(NO3)]n 2 and [Ag(MTP)(OTf)]n 3 (where MTP = 2-(Methylthio)Pyrazine and OTf = CF3SO3−) have been synthesized and characterized by different spectroscopic techniques. The single crystal X-ray study reveals that CPs 1 and 2 are two dimensional, whereas 3 is three dimensional. In the case of CP 1, MTP has two types of bonding behaviour. In one it is coordinated through the nitrogen of pyrazine only, leaving sulfur of –SMe free, whereas, in the other, it bonded through both sulfur and nitrogen of MTP. The sulfur of –SMe is coordinated to the neighbouring [Ag(MTP)]n chain in 2 whereas, in case of 3, sulfur of –SMe remain uncoordinated. Absorption and emission spectra of MTP and CPs have been studied in solution state. The spectral behaviour was supported by time dependent density functional theory. The emission behaviour of CPs in the presence of different metal ions confirms that only CP 1 has some affinity towards Hg(II) and Cu(II) ions. © 2019 Elsevier Ltd