Synthesis, Structures, and Properties of Four Novel HgII Complexes Based on Pyridine Acylamide Ligands

Abstract

In this work we synthesised four new pyridine acylamide complexes [HgI2(L1)] (1) and (2), [HgI2(L2)2] (3), and [HgI2(L3)]n (4) (L1 = N,N′-bis(3-pyridylmethyl)benzene-1,4-dicarboxamide, L2 = N4,N4′-bis(pyridin-3-yl)-[1,1′-biphenyl]-4,4′-dicarboxamide, L3 = N1,N3-bis(pyridin-3-ylmethyl)isophthalamide) by solvo(hydro)thermal reaction. Compounds 1 and 2 are supramolecular isomers prepared via variation of the reaction solvent, in which the HgII centres are bridged by L1 ligands to form one-dimensional (1D) helical chain or 1D meso-helical chain, respectively. Careful inspection of the structures reveal that formation of the isomers are mainly induced by the distinct configuration of L1 ligand and slight differences in coordination geometry of the HgII ions. Complex 3 shows a novel Z-shaped zero-dimensional structure with a L2–HgI2–L2–HgI2–L2 arrangement. In complex 4, flexible L3 ligands link HgI2 units to construct a 1D helical chain with an overall chiral structure, derived from spontaneous resolution. Luminescence properties of these four novel complexes were also explored.