Syntheses and Characterization of Two New M(II)-5,5′-dimethyl-2,2′-bipyridine (M = Cd and Pb) Coordination Polymers and Study of Their Thermal and Electrochemical Properties

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

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.

Structural and spectral study of coordination of 4,4′-dimethoxy-2,2′-bipyridine toward Zn(II) and Cd(II) containing thiocyanato or azido ligands

Three new compounds of zinc(II) and cadmium(II) with the ligand 4,4′-dimethoxy-2,2′-bipyridine (4,4′-dmo-2,2′-bpy), including cis-[Zn(4,4′-dmo-2,2′-bpy)2(SCN)2] (1), cis-[Cd(4,4′-dmo-2,2′-bpy)2(SCN)2] (2), and [Cd3(4,4′-dmo-2,2′-bpy)3(N3)5(OAc)] n (3), have been obtained as white single crystals by the branched tube method and characterized by elemental analysis, FT-IR and 1H, 13C NMR spectroscopy, and X-ray crystallography. Single-crystal structure analyses of the isostructural complexes 1 and 2 showed distorted octahedral geometry for zinc(II) and cadmium(II) with ZnN6 and CdN6 environments. Complex 3 reveals a rare coordination polymer containing octahedrally coordinated cadmium(II) expanding to chains by two different bridging modes, including Cd‒O‒C‒O‒Cd and Cd‒N‒Cd.