C–S bond cleavage by cobalt: synthesis, characterization and crystal structure determination of 1,2-di-(o-salicylaldiminophenylthio)ethane and its Co(III) product with C–S bond cleaved fragments

Nucleation of mercury sulfide by dealkylation

Metal sulfide minerals are assumed to form naturally at ambient conditions via reaction of a metallic element with (poly)sulfide ions, usually produced by microbes in oxygen-depleted environments. Recently, the formation of mercury sulfide (β-HgS) directly from linear Hg(II)-thiolate complexes (Hg(SR)₂) in natural organic matter and in cysteine solutions was demonstrated under aerated conditions. Here, a detailed description of this non-sulfidic reaction is provided by computations at a high level of molecular-orbital theory. The HgS stoichiometry is obtained through the cleavage of the S-C bond in one thiolate, transfer of the resulting alkyl group (R') to another thiolate, and subsequent elimination of a sulfur atom from the second thiolate as a thioether (RSR'). Repetition of this mechanism leads to the formation of RS-(HgS)_n-R chains which may self-assemble in parallel arrays to form cinnabar (α-HgS), or more commonly, quickly condense to four-coordinate metacinnabar (β-HgS). The mechanistic pathway is thermodynamically favorable and its predicted kinetics agrees with experiment. The results provide robust theoretical support for the abiotic natural formation of nanoparticulate HgS under oxic conditions and in the absence of a catalyst, and suggest a new route for the (bio)synthesis of HgS nanoparticles with improved technological properties.

Active versus passive substituent participation in the auxiliary-mediated asymmetric synthesis of an octahedral metal complex

Ambiguous chirality transfer: A surprising reversal of chirality transfer from carbon to metal is reported in the asymmetric synthesis of a chiral ruthenium complex, affording the metal-centered configuration Λ or Δ depending only on the chemical composition of the side chain of a chiral salicyloxazoline auxiliary.

N-(2-Thienylmethyl-ene)-2-(2-{[2-(2-thienylmethyl-eneamino)phen-yl]sulfan-yl}ethyl-sulfan-yl)aniline

The asymmetric unit of the title compound, C(24)H(20)N(2)S(4), contains one half-mol-ecule: a crystallographic centre of inversion is located at the mid-point of the two central C atoms. The thio-phene ring is oriented at a dihedral angle of 60.64 (3)° with respect to the benzene ring. In the crystal structure, π-π contacts between thio-phene rings [centroid-centroid distance = 3.581 (1) Å] may stabilize the structure. A weak C-H⋯π inter-action is also present.