Synthesis, spectroscopic and X-ray structural characterization of two novel mixed-ligand lead(II) complexes

Abstract

Two novel mixed-ligand complexes of lead(II), [Pb(Cup)2(Phen)]2](DPE) (1) and [Pb(Cup)(ONO2)(Phen)] (2) (Cup = cupferronato, Phen = 1,10-phenanthroline, and DPE = 1,2-di(4-pyridyl)ethylene), were synthesized in the presence of common bridging ligands which are usually used in synthesis of lead(II) coordination polymers as well as utilization of Cup and Phen as O,O′- and N,N′- chelates, respectively. Structural features of 1 and 2 in solution were investigated by 1H and 13C NMR experiments. The accurate assignment of these signals was inferred from a series of 1H–1H COSY, 1H–13C HSQC, and 1H–13C HMBC spectra. The solid-state structures of 1 and 2 were also investigated via single crystal XRD. By considering the obtained structural parameters, the coordination of 1 is hemidirected while 2 is suggested to be holodirectional. Additionally, complex 1 consist of dimers which are further associated via π-π stacking to a one-dimensional coordination polymer while complex 2 forming a step-like one-dimensional chain by an intermolecular interaction between each molecule and two nitrato groups of the two adjacent molecules. Both complexes showed significant antibacterial and antifungal characteristics in disc diffusion tests and they could be considered as new potent antimicrobial material.