Mercurophilic interaction in novel polynuclear Hg(ii)–2-aminoethanethiolates

Abstract

The reaction of 2-aminoethanethiol hydrochloride with Hg(2)Cl(2) in water yielded elemental mercury and one-dimensional polynuclear compounds [{Hg(3)Cl(5)(SCH(2)CH(2)NH(3))(3)}Cl](n) and [HgCl(SCH(2)CH(2)NH(2))(H(2)O)(2)](n) (2). The coordination environment around Hg in 1 and 2 is quite variable despite similar reaction conditions. The formation of a five-membered S/N chelate in 2 can be attributed to the use of base to produce a neutral ligand. Three independent types of Hg atoms, both three- and four-coordinate are observed in 1, whereas in 2, the Hg atom is tetracoordinate with S, N and Cl atoms in the primary coordination sphere. Despite distinct structural chemistry, the coordination environments in 1 and 2 are fairly similar with repeating units connected with bridged thiolate S atoms in addition to a terminal Cl attached to Hg. Intermolecular hydrogen-bonding involving amine protons, Cl and water molecules are responsible for a three-dimensional network in both 1 and 2. A short Hg...Hg distance of 3.564 A, indicates the presence of a mercurophilic interaction in 1. The compounds have been characterized by (1)H and (13)C NMR, UV-Vis, FT-IR, Raman, mass spectrometry, TGA and single X-ray crystallography.

Synthesis, spectroscopic characterization and antimicrobial studies of mercury(II) complexes of thiolates

“…The interaction of mercury(II) with sulfur-containing molecules is an important area in bioinorganic chemistry because such studies provide models for naturally occurring sulfur-containing compounds [1][2][3][4][5][6][7][8][9][10]. The biological chemistry of mercury is dominated by coordination to cysteine thiolate groups in agreement with the preference of this metal ion for the soft sulfur ligands and a great deal of research has been conducted to understand how the amino acid interacts with metals [11][12][13][14][15].…”

“…Although mercury(II) being a soft Lewis acid forms quit stable complexes with thiol groups [20][21][22][23], many thiolates remain labile and undergo ligand exchange, which is more pronounced in low (two and three)-coordinate compounds [24,25]. Mercurythiolates provide representative examples of the structural diversity shown by the extensive family of metal thiolates [5][6][7][8]13,[26][27][28]. They are well known for their unusual coordination environment and exhibit structural variability both in the solution form and solid states.…”

Role of Hg...Hg Interactions in Structure Stability of [HgX]- (X = Cl, Br, I) Based Inorganic-Organic Hybrid Compounds

“…The Hg…Hg distance in compound HgCl1 is calculated as 3.831(1) Å which shows that the structure is stabilized by metallophilic interactions apart from X-H…A and Cl…Cl secondary interactions 10,12 . Similar pattern of mercurophilic interactions is observed in HgCl2 derivative with Hg…Hg distance of 3.920(2) Å.…”

“…Hg…Hg interactions are designated as mercurophilic interactions and depicts an interesting phenomenon of d 10 …d 10 metal contacts [9][10][11][12] . As part of our research on secondary interactions in organic-inorganic hybrid materials 11 , three series of compounds whose crystal structures have already been reported have been selected based on [HgX] -, (X = Cl, Br, I) anion for study of mercurophilic interactions through crystallography data.…”

“…The Hg…Hg distance in compound HgBr1 is calculated as 3.970(1)Å which shows that the structure is stabilized by metallophilic interactions apart from X-H…A and Br…Br [minimum distance = 3.610(2)Å] secondary interactions 10,19 . Mercury atom at symmetry position 1+x, 0.5-y and 0.5+z establish a close contact with Hg located at 1-x, 0.5+y and 0.5-z as shown in Figure 3.…”