Photoinduced reaction of sulfur with cyclopentadienyliron dicarbonyl dimer and crystal structure of bis(cyclopentadienyliron)monocarbonyl tetrasulfide

Stability, Structure and Reconstruction of 1H-Edges in MoS2

Density functional studies of the edges of single-layer 1H-MoS₂ are presented. This phase presents a rich variability of edges that can influence the morphology and properties of MoS₂ nano-objects, play an important role in industrial chemical processes, and find future applications in energy storage, electronics and spintronics. The so-called Mo-100 %S edges vertical S-dimers were confirmed to be stable, however the authors also identified a family of metastable edges combining Mo atoms linked by two-electron donor symmetrical disulfide ligands and four-electron donor unsymmetrical disulfide ligands. These may be entropically favored, potentially stabilizing them at high temperatures as a "liquid edge" phase. For Mo-50 %S edges, S-bridge structures with 3× periodicity along the edge are the most stable, compatible with a Peierls' distortion arising from the d-bands of the edge Mo atoms. An additional explanation for this periodicity is proposed through the formation of 3-center bonds.

Low temperature activation of S8, Se(red) and α-Te with [Cp(BIG)Fe(CO)2] radicals

The bulky dimeric iron complex, [Cp(BIG)Fe(CO)2]2, readily activates elemental chalcogens (S8, Se(red) and α-Te) under mild conditions at room temperature. Six compounds containing Q2(2-) ligands (Q = S, Se) and a Te(2-) ligand, respectively, were isolated and completely characterized, including by X-ray diffraction techniques.

Kinetic and Mechanistic Aspects of Sulfur Recovery from Pd(2)I(2)(&mgr;-S)(&mgr;-dpm)(2) Using I(2) and Structures of Pd(II) Complexes with the Chelated Monosulfide of dpm

The Pd(2)X(2)(&mgr;-S)(dpm)(2) complexes (2) (X = I, Br) react with halogens to yield PdX(2)(dpm) (3) and elemental sulfur. Kinetic and mechanistic studies on the X = I system in CHCl(3) reveal that the reaction proceeds via addition of I(2) to give Pd(2)I(4)(dpm)(2) (4c), which then undergoes unimolecular decomposition to generate PdI(2)(dpm) (3c); the liberated sulfur concatenates to form elemental S(8). The addition reaction is in the stopped-flow time regime and is first-order in both 2c and I(2), with DeltaH() = 32 +/- 1 kJ mol(-)(1) and DeltaS() = -91 +/- 3 J K(-)(1) mol(-)(1). The slower decomposition reaction of 4c is first order in 4c, with DeltaH() = 80 +/-1 kJ mol(-)(1) and DeltaS() = -26 +/- 3 J K(-)(1) mol(-)(1). Byproduct PdX(2)(dpm(S)) (5) [dpm(S) = Ph(2)PCH(2)P(S)Ph(2)] also forms under some conditions via reaction of 3 with an S(n)() species (n < 8). Complexes 5 (X = Cl (a), Br (b), I (c)) were also synthesized directly, and the structure of the 5c species, as well as of [Pd(dpm(S))(2)]Cl(2), were determined by X-ray analyses that reveal the envelope configuration of the five-membered chelate ring.