Synthesis, structure and characterization of a new noncentrosymmetric Zn(II) complex with the 2-amino-5-chloropyridine ligand (AClPy)

Abstract

A new noncentrosymmetric Zn(II) complex with the monodentate ligand 2-amino-5-chloropyridine (AClPy), ZnCl₂(C₅H₅ClN₂)₂, has been prepared at room temperature and characterized by single crystal X-ray diffraction, ¹³C CP-MAS-NMR and IR spectroscopies. The basic coordination pattern of the AClPy coordinated metal cations is slighly distorted tetrahedral. The crystal structure is characterized by ZnCl₂N₂ tetrahedra interconnected via N-H···Cl hydrogen bonds generated by the NH₂ amino group to form chains extending along the (a-c) direction. The exocyclic N atom is an electron receiving center, which is consistent with features of imino resonance as evidenced by bond lengths and angles. The crystal structure is stabilized by sets of intra and intermolecular hydrogen bonds. The ¹³C CP-MAS NMR spectrum is discussed and the vibrational absorption bands are identified by infrared spectroscopy and theoretical calculations.