A set of new coordination compounds of cadmium(II)/mercury(II) halides/pseudohalides containing polyamines: Syntheses involving in situ metal–ligand reactions, crystal structures and molecular properties

Coordination compounds of the types [Hg(atta)][HgCl4] (1), [Cd5(apda)2Cl10]n (2), [Cd3(apda)2(N3)4]n(ClO4)2n (3) and [Cd2(bpda)(NCS)4]n (4) [atta = 4-(2-aminoethyl)-triethylenetetramine; apda = N-(2-aminoethyl)piperazine-1,4-diethylamine; bpda = N,N′-bis(2-aminoethyl)piperazine-1,4-diethylamine] are isolated using tetraethylenepentamine (tepa; for 1–3)/pentaethylenehexamine (peha; for 4) in presence of cadmium(II)/mercury(II) halides/pseudohalides. Structural studies reveal that polyamines tepa and peha undergo interesting in situ rearrangement to afford atta/apda and bpda ligands, respectively. Asymmetric unit in 1 comprises of discrete [Hg(atta)]2+ cation and [HgCl4]2− anion. Compound 2 consists of neutral pentanuclear core [Cd5Cl10] formed by three different types of chloride bridges propagating through binucleating bitridentate character of apda to afford a 1D ladder structure. 2D coordination polymer 3 with (4162)(4262) topology is formed through double μ1,1- and single μ1,3-azide bridges and binucleating behavior of apda. Alternating double μ1,3-thiocyanate and binucleating bis(tridentate) bridges in 4 result in a 1D zig-zag chain. Different kinds of non-covalent interactions promote dimensionalities in 1–4. Thermal behaviors of 1–4 are examined.