Tris(2-mercaptoimidazolyl)hydroborato Cadmium Thiolate Complexes, [Tm^But]CdSAr: Thiolate Exchange at Cadmium in a Sulfur-Rich Coordination Environment

Abstract

A series of cadmium thiolate compounds that feature a sulfur-rich coordination environment, namely [TmBut]CdSAr, have been synthesized by the reactions of [TmBut]CdMe with ArSH (Ar = C6H4-4-F, C6H4-4-But, C6H4-4-OMe, and C6H4-3-OMe). In addition, the pyridine-2-thiolate and pyridine-2-selenolate derivatives, [TmBut]CdSPy and [TmBut]CdSePy have been obtained via the respective reactions of [TmBut]CdMe with pyridine-2-thione and pyridine-2-selone. The molecular structures of [TmBut]CdSAr and [TmBut]CdEPy (E = S or Se) have been determined by X-ray diffraction and demonstrate that, in each case, the [CdS4] motif is distorted tetrahedral and approaches a trigonal monopyramidal geometry in which the thiolate ligand adopts an equatorial position; [TmBut]CdSPy and [TmBut]CdSePy, however, exhibit an additional long-range interaction with the pyridyl nitrogen atoms. The ability of the thiolate ligands to participate in exchange was probed by 1H and 19F nuclear magnetic resonance (NMR) spectroscopic studies of the reactions of [TmBut]CdSC6H4-4-F with ArSH (Ar = C6H4-4-But or C6H4-4-OMe), which demonstrate that (i) exchange is facile and (ii) coordination of thiolate to cadmium is most favored for the p-fluorophenyl derivative. Furthermore, a two-dimensional EXSY experiment involving [TmBut]CdSC6H4-4-F and 4-fluorothiophenol demonstrates that degenerate thiolate ligand exchange is also facile on the NMR time scale.

N-Heterocyclic Carbene Adducts of Main Group Elements and Their Use as Ligands in Transition Metal Chemistry

“…While the coordination chemistry of borate ligands such as 634 is still receiving considerable interest, , another important facet was added to this field in 1999 by Hill and co-workers, who observed that the B–H bond in complexes of 634 and 635 can be activated to establish boron–metal interactions. Thus, the first metallaboratrane 638 was prepared by reaction of K­( 634 ) with the vinyl complex [Ru­(CHCHCPh 2 OH)­Cl­(CO)­(PPh 3 ) 2 ], which afforded 638 with elimination of the alkene CH 2 CHCPh 2 OH (Scheme ).…”

“…While the coordination chemistry of borate ligands such as 634 is still receiving considerable interest, 811,812 The molecular structure of this complex revealed octahedral and tetrahedral coordination geometries around the ruthenium and boron atoms, respectively, with a short Ru−B bond length of 2.161( 5) Å (Figure 78). 813 This interaction was described as a metal-to-boron dative bond, making this boron-bridged tris(imidazolin-2-thione) ligand a prominent member of the extensively studied class of ambiphilic σ-acceptor (Z-type) 33 ligands.…”

Heterogeneous Fenton-like activity of novel metallosalophen magnetic nanocomposites: significant anchoring group effect

“…To investigate the effect of anchoring group, 4-aminopyridine was replaced by 2-aminoethanthiol to react with (3-oxopropyl) trimethoxysilan, 17 producing a new imine compound containing a thiolate group denoted as SAET (Scheme 1). Thiolate ligands are of extreme interest in coordination chemistry, 25 because of key function of thiolate groups of cysteine residues in iron and zinc enzymes. 26 They have also found important applications in the elds of nanoscience.…”