1,2,4-triazine derived binuclear lead(ii) complexes: synthesis, spectroscopic and structural investigations and application in organic light-emitting diodes (OLEDs)

Abstract

Two novel binuclear complexes of Pb(II) were synthesized by reacting a 3-(2-pyridyl)-5-(4-methoxyphenyl)-1,2,4-triazine (PMPT) ligand with different anionic co-ligands (1: bromide, 2: acetate and isothiocyanate) in a 1 : 1 molar ratio of PMPT ligands to lead(II) salts. The complexes, [Pb₂(μ-PMPT)₂Br₄] (1) and [Pb₂(μ-PMPT)₂((μ-CH₃COO)₂(NCS)₂] (2), were characterized using various physicochemical techniques such as CHN analysis, FT-IR spectroscopy, and ¹H NMR spectroscopy. Additionally, their structures were determined using single-crystal X-ray diffraction. Based on the obtained structural parameters, complex 1 exhibited a PbN₃Br₂ environment, while complex 2 displayed a PbN₄O₃ environment, with holodirected and hemidirected coordination spheres, respectively. Within the crystal network of the complexes, there were interactions involving C–H⋯X (X: O, S, N) as well as π–π stacking. The Pb(II) complexes were further investigated for their potential use as the emitting layer in organic light-emitting devices (OLEDs). The current–voltage and luminescence-voltage characteristics, as well as the electroluminescence (EL) properties of the complexes, were studied.