Synthesis, structure and luminescence behaviour of bis(tridentate) Schiff base bridged dinuclear lead(II) pseudohalides

Two pentacoordinated dinuclear lead(II) compounds [Pb2(pbap)(N3)4] (1) and [Pb2(pbap)(NCS)4] (2) [pbap = N-((1-pyridin-2-yl)benzylidene)-N′-[2-(4-{2-[((1-pyridin-2-yl)benylidene)amino]ethyl}piperazin-1-yl)ethyl]amine] are prepared and characterized using microanalytical, spectroscopic, thermal and other physicochemical results. Single crystal X-ray diffraction measurements have been made to define the metal coordination spheres. Structural analyses reveal dinucleating bis(tridentate) behaviour of the hexadentate Schiff base (pbap) binding two metal ions. In the centrosymmetric dimers 1 and 2, each lead(II) center adopts a distorted square pyramidal geometry with PbN5 chromophore ligated by each (Np, Ni, Na) donor set of pbap and two N atoms of terminal pseudohalides. In DMF solutions at room temperature the complexes display high-energy intraligand 1(π–π∗) fluorescence.