The first coordination polymers with an [O]2[N]P(S)-Hg segment: a combined experimental, theoretical and database study†
Abstract
The study of one-dimensional coordination polymers {Hg2Cl4L1}n (1), {HgBr2L1}n (2) and {Hg2Cl4L2}n (3) (L1 = (S)P(OC2H5)2NHC6H4NHP(S)(OC2H5)2 and L2 = (S)P(OC2H5)2NC4H8NP(S)(OC2H5)2) is the first such structural study of Hg(II) coordination polymers with (O)2(N)PS-based ligands. The mercury atoms adopt a distorted trigonal pyramidal environment, Hg(Cl)3(S) for 1 and 3 and Hg(Br)2(S)2 for 2, and the difference observed in the stoichiometry of mercury halide to the thiophosphoramide ligand in 1 and 3 with respect to the one in 2 is a result of the formation of the Hg2Cl2 ring, however, the molar ratio 2 : 1 of HgX2 (X = Cl and Br) to ligand was used for the preparation of all three complexes. The strengths of mercury-sulfur and mercury-halide covalent bonds are evaluated by theoretical calculations (QTAIM and NBO) which show their principally electrostatic nature with a partial covalent contribution. The energies of interactions building supramolecular assemblies and intramolecular interactions, i.e. NH⋯Cl, NH⋯Br, CH⋯Cl, CH⋯Br, CH⋯O, CH⋯S and CH⋯π, are theoretically evaluated. The characteristic structural features arising from the aromatic/aliphatic linkers in the ligands and chloride/bromide attached to mercury are investigated by Hirshfeld surface analysis and fingerprint plots.