Versatile coordination environment and interplay of metal assisted secondary interactions in the organization of supramolecular motifs in new Hg(II)/PhHg(II) dithiolates

Abstract

New mercury(II) complexes of the form [PhHg(L)] (L=L1 (1), L2 (2), L3′ (3), L4=(4)); [Hg(L)2] (L=L5 (5), L4 (7) and [Hg2(L6)4] (6) have been synthesized and characterized by micro analysis and X-ray crystallography. Both 1 and 2 are linear; complex 2 revealed intramolecular Hg⋯O bonding interactions. Complex 3 possesses T-shaped geometry in a linear polymeric chain motif. Although serendipitously formed, 3 is the first example of a metal trithioxanthate complex. 4 is a typical dimer and in 5, a helical chain motif is generated via Hg⋯S contacts. 6 is a dinuclear complex with distorted square pyramidal geometry. 7 is mononuclear with a tetrahedrally coordinated mercury(II) ion. All complexes are luminescent in solution and solid state. In 2 the nature of Hg⋯O interactions have been assessed by DFT calculations and the electronic transitions in 3 have been corroborated by TDDFT calculations.