Syntheses and structures of two- and one-dimensional organic–inorganic hybrid compounds assembled from PbI2 and 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene

The reaction of the elongated Schiff base 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene and PbI2 in DMF gave rise to two- and one-dimensional organic–inorganic hybrid compounds [PbI2(C12H10N4)]2n·0.5n(C12H10N4) (1) and [PbI2(C12H10N4)]n (2), respectively, at different M/L ratios 2:1 and 1:1,and their structures were determined by single-crystal X-ray crystallography. Compound 1 exhibits 2D-layered structure formed from PbI2 chains bridged by the Schiff base with the free ligand regularly lying between two layers, while compound 2 possesses a 1D-zig-zag chain where lead atom is in the rarely observed four-coordinate holodirected configuration. 2 is the first example of PbI2-based polymer with terminal coordinated iodine atoms.