Mercury(II) acetate/thiocyanate coordination polymers with n-donor ligands, spectroscopic, thermal and structural studies

Three new mercury(II) coordination polymers, [Hg2(μ-bpa)(μ-SCN)2(μ-CH3COO)2]n (1), [Hg2(μ-4-bpdb)1.5(μ-CH3COO)(μ1,1- SCN)(μ1,3-SCN)(SCN)]n · CH3CN (2) and [Hg(μ-3-bpdb)(CH3COO)2]n (3) {(bpa = 1,2-bis(4-pyridyl)ethane, 4-bpdb) = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene and 3-bpdb = 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene, have been synthesized and characterized by CHN elemental analysis and IR spectroscopy. The single crystal X-ray data show the compound 1 is two-dimensional coordination polymer as a result of simultaneously bridging 1,2-bis(4-pyridyl)ethane, acetate and thiocyanate ligands. The single-crystal X-ray data of the compound 2 show that the complex to be a two-dimensional polymer, one of Hg atoms has four-coordinate and one of them has seven-coordinate. Three SCN− anions show three different coordination modes with terminal, μ1,1-bridge and μ1,3-bridge fashions. The structural studies of compound 3 show the structure may be considered a one-dimensional coordination polymer of mercury(II) consisting of linear chains formed by a bridging 3-bpdb ligand. The thermal stabilities of these compounds were studied by thermal gravimetric (TG) and differential thermal analyses (DTA).