A synthetic model of Hg(ii) sequestration

Abstract

Tridentate ligand N-(2-pyridylmethyl)-N-(2-(ethylthiolato)amine (L) forms the novel complex [Hg(5)(L)(6)](ClO(4))(4).toluene () with a bicyclo[3.3.3] Hg(5)S(6) core and 4-, 5- and 6-coordinate metal centers; characterization of a solution of by ESI-MS revealed elaborate speciation involving [Hg(n)L(n+1)(ClO(4))(n-2)](+), [Hg(n)L(n)(ClO(4))(n-1)](+) and [Hg(n)L(n-1)(ClO(4))(n)](+) ion families.

Synthesis, Solid State, Solution and ESI‐MS Studies of Zinc(II) Cluster Complexes with a Branched Mixed Donor Thiolate Ligand

“…The correlated intensities and vicinal coupling resolution of these peaks as a function of temperature suggested they are associated with a single molecular entity undergoing rapid intramolecular reorganization under non‐cryogenic conditions. Since very similar proton NMR behavior was observed for [Hg 5 L′ 6 ] 4+ , these peaks have been assigned to [Zn 5 L 6 ] 4+ ( 5 ) (Scheme ). To the best of our knowledge, the only zinc‐containing structurally characterized complexes with a bicyclic [3.3.3] M 5 S 6 are two Ni 3 Zn 2 S 6 complexes with the zinc atoms located at the bridgehead positions , .…”

“…Self‐assembly reactions between metal ions and thiolate ligands involve the interplay of metal coordination preferences, ligand architecture and reaction conditions. The d 10 divalent group 12 metal ions readily adopt coordination numbers of 4, 5 or 6, which facilitates formation of a variety of thiolate bridged complexes in solution . However, recrystallization from the associated milieu rarely permits isolation of more than a single complex and ligand exchange rates with mono‐ and bidentate thiolates are prohibitively fast for detailed analysis of solution equilibria.…”

“…Significantly, while ligands favoring formation of mononuclear complexes commonly produce group 12 metal ion complexes with comparable composition under similar conditions, the small clusters isolated from bridging thiolate ligands can vary considerably in composition , . Efforts to prepare a Zn(II) complex of LH with trimethylamine as base consistently led to the isolation of the unusual spirobicylic complex [Zn((Zn L ) 2 (µ‐OH)) 2 ](ClO 4 ) 4 · CH 3 CN · 7H 2 O ( 1 ) rather than a carbonate complex.…”

Metal Substitution and Solvomorphism in Alkylthiolate-Bridged Zn3 and HgZn2 Metal Clusters

“…Because the H a protons of related multidentate pyridyl ligands have typically demonstrated much greater sensitivity to subtle differences in the environment when bound to group 12 metal ions, coincidental stereoisomer chemical shifts for the remaining protons are reasonable (Figure 17c). 30,43−45 Significantly, at −40 °C, the two chemical shift environments for H a were better resolved, and a second chemical shift environment was partially resolved for H h with roughly one-third the intensity of the main H h resonance (Figure S7). At an elevated temperature, the resonances for H a and all aliphatic protons collapsed to broad singlets, consistent with a thermally-induced bond cleavage process permitting interconversion of the stereoisomers.…”

“…In a recent work, we used tridentate ligand N -(2-pyridylmethyl)- N -(2-(ethylthiolato)amine) ( LH ; Figure 1) to prepare a novel complex with a bicyclo[3.3.3]Hg 5 S 6 core. 30 On the basis of the electrospray ion-mass spectrometry (ESI-MS) evidence, this complex crystallized from a solution containing complexes with a variety of Hg/ L stoichiometries, a process analogous to the physiological sequestration of Hg(II) in the kidneys by metallothionein.…”