Three new HgII metal–organic polymers generated from 1,4-bis(n-pyridyl)-3,4-diaza-2,4-hexadiene ligands

Three new polymeric mercury(II) thiocyanate coordination polymers, {[Hg2(L4)(SCN)4]n (1), [Hg2(μ-L5)(μ-SCN)4]n[Hg2(μ-L5)(μ-SCN)4]2n (2) and [Hg(L6)(SCN)2]n (3); L4 = 2,5-bis(2-pyridyl)-3,4-diaza-2,4-hexadiene, L5 = 2,5-bis(3-pyridyl)-3,4-diaza-2,4-hexadiene and L6 = 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene) were prepared from reactions of mercury(II) thiocyanate with three organic nitrogen donor-based ligands under thermal gradient conditions using the branched tube method and fully characterized by infrared spectroscopy, elemental analysis, thermo gravimetric analysis, and single crystal X-ray diffraction. The compounds are structurally diverse and show very interesting structural motifs: the compound 1 is one-dimensional heterochiral double-chains. In compound 2, the bridging ligand L5 adopts a transoid conformation and the network contains two interpenetrating coordination polymers, a 2D net and a 1D double-chain. The crystal structure of 3 consists of one-dimensional zigzag chains. Solid-state luminescent spectra of the compounds 1 and 3 indicate intense fluorescent emissions at ca. 393 nm and 363 nm, respectively.